2024/10/06 更新

写真a

ゴウコン ノブユキ
郷右近 展之
GOKON Nobuyuki
所属
教育研究院 自然科学系 生産デザイン工学系列 准教授
工学部 工学科 准教授
職名
准教授
外部リンク

学位

  • 博士(工学) ( 2000年3月   東京工業大学 )

  • 修士(工学) ( 1997年3月   東京工業大学 )

  • 学士(工学) ( 1995年3月   茨城大学 )

研究キーワード

  • Medical Organism Engineering and Material Science of Organism. Inorganic compounds. Metallic materials in general

  • Metal oxide for use in solar thermochemical heat storage

  • Metallic alloy for use in solar latent heat storage

  • Thermochemical two-step CO2 splitting

  • 水素エネルギー生産

  • エネルギー変換

  • 高温太陽集光熱

  • バイオマスのソーラーガス化

  • 高温化学蓄熱

  • 高温潜熱蓄熱

  • 触媒材料

  • ナノ粒子

  • 金属物性学

  • 無機材料化学

研究分野

  • ナノテク・材料 / 無機材料、物性

  • ナノテク・材料 / 金属材料物性

  • ライフサイエンス / 生体材料学

  • ものづくり技術(機械・電気電子・化学工学) / 触媒プロセス、資源化学プロセス

  • ナノテク・材料 / エネルギー化学

  • エネルギー / 地球資源工学、エネルギー学

  • ナノテク・材料 / 金属生産、資源生産

  • ライフサイエンス / 生体医工学

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経歴

  • 新潟大学   工学部 工学科   准教授

    2019年2月 - 現在

  • 新潟大学   研究推進機構   准教授

    2017年4月 - 2019年1月

  • 新潟大学   研究推進機構 超域学術院   准教授

    2011年4月 - 2017年3月

  • 新潟大学   超域研究機構   准教授

    2009年4月 - 2011年3月

  • 新潟大学   自然科学研究科 材料生産システム専攻   助教

    2007年4月 - 2009年3月

  • 新潟大学   自然科学研究科   助手

    2005年4月 - 2007年3月

  • 東京工業大学   理工学研究科/生命理工学研究科

    2003年4月 - 2005年3月

  • 東京工業大学   炭素循環素材(エネルギー)研究センター

    2000年4月 - 2003年3月

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学歴

  • 東京工業大学   総合理工学研究科   材料物理科学専攻

    1997年4月 - 2000年3月

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    国名: 日本国

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  • 東京工業大学   総合理工学研究科   材料科学専攻

    1995年4月 - 1997年3月

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    国名: 日本国

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  • 茨城大学   工学部   物質工学科

    1991年4月 - 1995年3月

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    国名: 日本国

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所属学協会

  • 日本化学会

    2000年4月 - 現在

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  • 日本エネルギー学会 新エネルギー・水素部会

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  • アメリカ機械学会 太陽エネルギー部会

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  • 日本太陽エネルギー学会 太陽熱部会

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  • 粉体粉末冶金協会

    2000年4月 - 2003年3月

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  • 日本金属学会

    1996年4月 - 2010年3月

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委員歴

  • 日本エネルギー学会 新エネルギー・水素部会   部会長  

    2023年4月 - 現在   

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    団体区分:学協会

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  • 欧州科学財団   研究プロポーザル審査官  

    2021年4月 - 現在   

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    団体区分:その他

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  • 日本エネルギー学会   新エネルギー・水素部会 副部会長  

    2019年4月 - 2023年3月   

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    団体区分:学協会

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  • 文部科学省 科学技術・学術政策研究所 科学技術予測センター   NISTEP専門調査員  

    2017年 - 現在   

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    団体区分:政府

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  • 日本太陽エネルギー学会   太陽エネルギー部会  

    2017年 - 現在   

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    団体区分:学協会

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  • 日本エネルギー学会   新エネルギー・水素部会 庶務幹事委員  

    2017年 - 2019年3月   

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    団体区分:学協会

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  • IEA SolarPACES国際会議   Scientific Committee  

    2014年 - 現在   

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    団体区分:学協会

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  • 日本エネルギー学会   新エネルギー部会 編集委員  

    2011年 - 2017年   

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    団体区分:学協会

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  • 新潟大学化学教育協議会   幹事委員  

    2010年 - 2011年   

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    団体区分:その他

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  • 日本エネルギー学会   新エネルギー部会 幹事委員  

    2009年 - 2017年   

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    団体区分:学協会

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  • 日本エネルギー学会   学会大会実行委員  

    2009年 - 2011年   

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    団体区分:学協会

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  • 日本化学会関東支部   新潟地方大会 大会実行委員  

    2009年   

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    団体区分:学協会

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論文

  • Effects of heating rate and drying condition on thermochemical pyrolysis of spent coffee grounds in a windowed internally-circulating fluidized bed reactor 査読

    Nobuyuki Gokon, Yusuke Sasada, Hiroshi Seto, Tadaaki Shimizu, Selvan Bellan

    AIP Conf. Proc., SolarPACES: SOLAR POWER & CHEMICAL ENERGY SYSTEMS: 27th International Conference on Concentrating Solar Power and Chemical Energy Systems   2815   130003 - 130003   2023年10月

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    担当区分:筆頭著者, 最終著者, 責任著者   記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:AIP Publishing  

    DOI: 10.1063/5.0148539

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  • Temperature impacts on reactivity of La0.7A0.3Mn0.9Cr0.1O3-δ of perovskite oxides in a thermochemical two-step H2O/CO2 splitting 査読

    Hiroki Sawaguri, Yoshikazu Iwamura, Selvan Bellan, Nobuyuki Gokon

    AIP Conf. Proc., SolarPACES: SOLAR POWER & CHEMICAL ENERGY SYSTEMS: 27th International Conference on Concentrating Solar Power and Chemical Energy Systems   2815   130007 - 130007   2023年10月

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    担当区分:最終著者, 責任著者   記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:AIP Publishing  

    DOI: 10.1063/5.0149712

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  • Redox performance and optimization of the chemical composition of lanthanum-strontium-manganese-based perovskite oxide for two-step thermochemical CO2 splitting 招待 査読

    Hiroki Sawaguri, Daichi Yasuhara, Nobuyuki Gokon

    Processes   11   2717   2023年9月

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    担当区分:最終著者, 責任著者   記述言語:英語   掲載種別:研究論文(学術雑誌)  

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  • Progress in concentrated solar power, photovoltaics, and integrated power plants towards expanding the introduction of renewable energy in the Asia/Pacific region 招待 査読

    Nobuyuki Gokon

    Current Sustainable Renewable Energy Reports   10   250 - 263   2023年8月

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    担当区分:筆頭著者, 最終著者, 責任著者   記述言語:英語   掲載種別:研究論文(学術雑誌)  

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  • Comparative Study of Heat-Discharging Kinetics of Fe-Substituted Mn2O3/Mn3O4 Being Subjected to Long-Term Cycling for Thermochemical Energy Storage 招待 査読

    Nobuyuki Gokon, Fumiya Ohashi, Hiroki Sawaguri, Kosuke Hayashi

    Energies   16 ( 8 )   3367   2023年4月

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    担当区分:筆頭著者, 責任著者   記述言語:英語   掲載種別:研究論文(学術雑誌)  

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  • Long-Term Thermal Cycling Test and Heat-Charging Kinetics of Fe-Substituted Mn2O3 for Next-Generation Concentrated Solar Power Using Thermochemical Energy Storage at High Temperatures 招待 査読

    Nobuyuki Gokon, Kosuke Hayashi, Hiroki Sawaguri, Fumiya Ohashi

    Energies   15 ( 13 )   4812-1 - 4812-24   2022年6月

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    担当区分:筆頭著者, 責任著者   記述言語:英語   掲載種別:研究論文(学術雑誌)  

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  • A review on high‐temperature thermochemical heat storage: Particle reactors and materials based on solid–gas reactions

    Selvan Bellan, Tatsuya Kodama, Nobuyuki Gokon, Koji Matsubara

    WIREs Energy and Environment   11 ( 5 )   2022年5月

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    掲載種別:研究論文(学術雑誌)   出版者・発行元:Wiley  

    Abstract

    In order to produce electricity beyond insolation hours and supply to the electrical grid, thermal energy storage (TES) system plays a major role in CSP (concentrated solar power) plants. Current CSP plants use molten salts as both sensible heat storage media and heat transfer fluid, to operate up to 560°C. To meet the future high operating temperature and efficiency, thermochemical storage (TCS) emerged as an attractive alternatives for next generation CSP plants. In these systems, the solar thermal energy is stored by endothermic reaction and subsequently released when the energy is needed by exothermic reversible reaction. This review compares and summarizes different thermochemical storage systems that are currently being investigated, especially TCS based on metal oxides. Various experimental, numerical, and technological studies on the development of particle reactors and materials for high‐temperature TCS applications are presented. Advantages and disadvantages of different types heat storage systems (sensible, latent, and thermochemical), and particle receivers (stacked, fluidized, and entrained), have been discussed and reported.

    This article is categorized under:Sustainable Energy > Solar Energy

    Emerging Technologies > Energy Storage

    Emerging Technologies > Materials

    DOI: 10.1002/wene.440

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    その他リンク: https://onlinelibrary.wiley.com/doi/full-xml/10.1002/wene.440

  • Two-step thermochemical CO2 splitting using partially-substituted perovskite oxides of La0.7Sr0.3Mn0.9X0.1O3 for solar fuel production 招待 査読

    Hiroki Sawaguri, Nobuyuki Gokon, Kosuke Hayashi, Yoshikazu Iwamura, Daichi Yasuhara

    Frontiers in Energy Research, section Solar Energy   10   872959-1 - 872959-21   2022年5月

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    担当区分:責任著者   記述言語:英語   掲載種別:研究論文(学術雑誌)  

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  • Fluidization behavior of redox metal oxide and spinel particles to develop high-energy-density thermal energy storage system for concentrated solar power applications

    Genta TSURUMAKI, Selvan BELLAN, Koji MATSUBARA, Tatsuya KODAMA, Mitsuho NAKAKURA, Nobuyuki GOKON, Hyun SEOK CHO, Karthik MANI, Sakthivel SHANMUGASUNDARAM

    Journal of Thermal Science and Technology   17 ( 2 )   22 - 00061   2022年

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    掲載種別:研究論文(学術雑誌)   出版者・発行元:Japan Society of Mechanical Engineers  

    DOI: 10.1299/jtst.22-00061

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  • Development of Synthesis and Fabrication Process for Mn-CeO2 Foam via Two-Step Water-Splitting Cycle Hydrogen Production

    Hyun-Seok Cho, Tatsuya Kodama, Nobuyuki Gokon, Selvan Bellan, Jong-Kyu Kim

    Energies   14 ( 21 )   6919 - 6919   2021年10月

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    掲載種別:研究論文(学術雑誌)   出版者・発行元:MDPI AG  

    The effects of doping manganese ions into a cerium oxide lattice for a thermochemical two-step water-splitting cycle to produce oxygen and hydrogen and new synthesis methods were experimentally investigated. In order to comparison of oxygen/hydrogen producing performance, pristine CeO2, a coprecipitation method for Mn-CeO2, and a direct depositing method for Mn-CeO2 with different particle sizes (50~75, 100–212, over 212 μm) and doping extents (0, 5, 15 mol%) were tested in the context of synthesis and fabrication processes of reactive metal oxide coated ceramic foam devices. Sample powders were coated onto zirconia (magnesium partially stabilized zirconia oxide, MPSZ) porous foam at 30 weight percent using spin coating or a direct depositing method, tested using a solar reactor at 1400 °C as a thermal reduction step and at 1200 °C as a water decomposition step for five repeated cycles. The sample foam devices were irradiated using a 3-kWth sun-simulator, and all reactive foam devices recorded successful oxygen/hydrogen production using the two-step water-splitting cycles. Among the seven sample devices, the 5 mol% Mn-CeO2 foam device, that synthesized using the coprecipitation method, showed the greatest hydrogen production. The newly suggested direct depositing method, with its contemporaneous synthesis and coating of the Mn-CeO2 foam device, showed successful oxygen/hydrogen production with a reduction in the manufacturing time and reactants, which was lossless compared to conventional spin coating processes. However, proposed direct depositing method still needs further investigation to improve its stability and long-term device durability.

    DOI: 10.3390/en14216919

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  • Phase change material of copper-germanium alloy as solar latent heat storage at high temperatures 招待 査読

    Nobuyuki Gokon, Chew Shun Jie, Yuya Nakano, Shogo Okazaki, Tatsuya Kodama, Tsuyoshi Hatamachi, Selvan Bellan

    Frontiers in Energy Research, section Solar Energy   9   696213-1 - 696213-19   2021年6月

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    担当区分:筆頭著者, 責任著者   記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Frontiers Media SA  

    A copper–germanium alloy (Cu–Ge alloy) was examined as a phase change material, at temperatures exceeding 600°C, for latent heat storage in solar thermal applications. First, the thermo-physical properties of the Cu–Ge alloy were examined using differential scanning calorimetry, thermomechanical analysis, and laser flash analysis. Second, to evaluate the thermal response and reliability of the Cu–Ge alloy, the cyclic properties of thermal charge/discharge were examined under various thermal conditions. The alloys obtained after the tests were examined for their chemical compatibility with the stainless steel container using an electron probe micro analyzer. The elemental distribution of each Cu–Ge alloy was evaluated using cyclic performance tests. Finally, the chemical compatibility of the Cu–Ge alloy was evaluated using a high-temperature test with candidate materials of a phase change material container vessel [stainless steel (SUS310S), Inconel625, silicon carbide (SiC), and alumina (Al2O3)]. The Cu–Ge alloy exhibited significant potential as a latent heat storage material in next-generation solar thermal power plants because it demonstrates various advantages, including a superior storage capacity at a temperature of 644°C, temperature coherence to the phase diagram, a quick thermal response, satisfactory cyclic behavior of charge/discharge modes, a thermodynamically stable metallographic structure, and non-reactivity with container ceramic materials (SiC and Al2O3).

    DOI: 10.3389/fenrg.2021.696213

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  • Chemical compatibility of Cu-Ge alloy with container materials for latent heat storage system 査読

    Nobuyuki Gokon, Chew Shun Jie, Selvan Bellan, Tatsuya Kodama, Tsuyoshi Hatamachi, Hyunseok Cho

    AIP Conference Proceedings   2303   2020年12月

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    担当区分:筆頭著者, 責任著者   掲載種別:研究論文(国際会議プロシーディングス)  

    Latent heat storage technology in CSP plant has been studied to enhance the dispatchability of solar energy in order to meet fluctuating electricity needs. A novel concept using metal alloys as latent heat storage material gives way to achieve this technology. In this paper, we analyzed the structural and thermal properties of Cu-Ge alloy to evaluate the potential of metallic PCM for high temperature TES application. Containment options for metallic PCM were explored and the materials are selected for long term operation. Compatibility tests of stainless steel, alumina and SiC ceramics under inert atmosphere were performed at high temperatures (800°C) for a duration of 1 month (720 h) in order to develop a suitable container material for thermal energy storage system.

    DOI: 10.1063/5.0028722

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  • Numerical analysis on solidification process of PCM in triplex-tube thermal energy storage system

    Koya Hirai, Selvan Bellan, Koji Matsubara, Tatsuya Kodama, Nobuyuki Gokon, Hyun Seok Cho

    AIP Conference Proceedings   2303   2020年12月

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    掲載種別:研究論文(国際会議プロシーディングス)  

    Considerable attention is being paid in recent years to develop and improve alternative technologies to replace fossil fuels due to pollution problems and limited conventional energy sources. Solar thermal energy has been considering as one of the most attractive renewable sources to provide solution to the aforementioned problems. In recent years, latent thermal energy storage systems using phase change materials (PCMs) have been developed to aid energy supply and demand of solar thermal power plants. As one of the obstacles of these systems is the low thermal conductivity of PCMs, ceramic fin has been used in this study to enhance heat transfer rate between the PCM and heat transfer fluid. To assess the heat transfer characteristics of the triplex-tube thermal energy storage system with ceramic fin, a numerical model has been developed and the effect of fin for various Stefan numbers has been studied numerically. The heat transfer and solidification rates are significantly enhanced when connecting the fins between the inner and outer tubes.

    DOI: 10.1063/5.0028873

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  • Thermochemical two-step CO<inf>2</inf> splitting using La<inf>0.7</inf>Sr<inf>0.3</inf>Mn<inf>0.9</inf>Cr<inf>0.1</inf>O<inf>3</inf> of perovskite oxide for solar fuel production 査読

    Hiroki Sawaguri, Nobuyuki Gokon, Naoki Ito, Selvan Bellan, Tatsuya Kodama, Hyun Seok Cho

    AIP Conference Proceedings   2303   2020年12月

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    担当区分:責任著者   掲載種別:研究論文(国際会議プロシーディングス)  

    A thermochemical two-step water-splitting cycle using perovskite oxide of La0.7Sr0.3Mn0.9Cr0.1O3 was examined for carbon monoxide production from CO2 using concentrated solar radiation. Previously, the authors proved the perovskite oxide can thermochmically split H2O via two-step process into oxygen and hydrogen in an individual step. In this study, a thermochemical two-step CO2 splitting cycle using the perovskite oxide was examined for the reactivity and repeatability of redox reaction at CO2 spitting temperatures of 1000-1200 °C. The reactivity and repeatability for two-step CO2 splitting was compared to those for H2O splitting operating at the same temperature level.

    DOI: 10.1063/5.0028681

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  • Experimental Study of Mn-CeO<inf>2</inf> Coated Ceramic Foam Device for Two-step Water Splitting Cycle Hydrogen Production with 3kW Sun-simulator

    Hyun Seok Cho, Tatsuya Kodama, Nobuyuki Gokon, Selvan Bellan, Naoyoshi Nishigata

    AIP Conference Proceedings   2303   2020年12月

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    掲載種別:研究論文(国際会議プロシーディングス)  

    In this paper, the effect of doping of Manganese on to Cerium oxide for thermochemical two-step water splitting cycle for produce the hydrogen was experimentally studied. In order to compare the oxygen/hydrogen productivity, pure CeO2, coprecipitation method applied Mn-CeO2, and direct doping calcination method adopted Mn-CeO2 were used to thermo-chemical two-step water splitting cycle tests. The synthesized sample powders were coated on the reticulated porous foam device and tested in the fixed bed type reactor for the temperature of 1400 C for thermal reduction step, and 1200 C for water decomposition step through 5 cyclic tests. The redox reactive foam devices were irradiated by 3kW sun-simulator, and all samples recorded successful oxygen/hydrogen production. Among the 3 sample devices, the 15 mol% Mn-CeO2 foam device which synthesized by direct doping calcination method shows highest hydrogen production amount and H2/O2 conversion ratio. o o

    DOI: 10.1063/5.0029890

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  • Thermochemical H<inf>2</inf>O splitting using LaSrMnCrO<inf>3</inf> of perovskite oxides for solar hydrogen production 査読

    Nobuyuki Gokon, Kazuki Hara, Naoki Ito, Hiroki Sawaguri, Selvan Bellan, Tatsuya Kodama, Hyun Seok Cho

    AIP Conference Proceedings   2303   2020年12月

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    担当区分:筆頭著者, 責任著者   掲載種別:研究論文(国際会議プロシーディングス)  

    A thermochemical two-step water-splitting cycle using perovskite oxide of La0.7Sr0.3Mn0.9Cr0.1O3 was examined for hydrogen production from water using concentrated solar radiation. The impact of the thermal reduction temperatures of 1000–1350 °C on oxygen/hydrogen productivity and repeatability was examined for hydrogen production at a water decomposition temperature of 1200 °C. The sample displayed relatively high evolution rates of oxygen at TR temperatures of 1350-1300°C, and showed similar rate at TR temperatures of 1000-1200 °C. After the sample was subjected to the TR step at temperatures of 1350-1300 °C, the obtained samples were superior hydrogen production rate to the others. On the other hand, the sample provided relatively good reactivities and repeatabilities for oxygen release and hydrogen production with a small production level without coagulation or sintering during the TR temperatures of 1000-1200 °C.

    DOI: 10.1063/5.0028720

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  • Thermal charge/discharge performance of iron–germanium alloys as phase change materials for solar latent heat storage at high temperatures 査読

    Nobuyuki Gokon, Chew Shun Jie, Yuya Nakano, Tatsuya Kodama, Selvan Bellan, Hyun seok Cho

    Journal of Energy Storage   30   101420-1 - 101420-18   2020年3月

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    担当区分:筆頭著者, 責任著者   記述言語:英語   掲載種別:研究論文(学術雑誌)  

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  • Thermochemical two-step water splitting cycle using perovskite oxides based on LaSrMnO3 redox system for solar H2 production 査読

    Nobuyuki Gokon, Kazuki Hara, Yuta Sugiyama, Selvan Bellan, Tatsuya Kodama, Cho Hyun-seok

    Thermochimica Acta   680   178374-1 - 178374-13   2019年10月

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    担当区分:筆頭著者, 責任著者   記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.tca.2019.178374

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  • Heat transfer and particulate flow analysis of a 30 kW directly irradiated solar fluidized bed reactor for thermochemical cycling 査読

    Selvan Bellan, Tatsuya Kodama, Koji Matsubara, Nobuyuki Gokon, Hyun Seok Cho, Kousuke Inoue

    Chemical Engineering Science   203   511 - 525   2019年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.ces.2018.09.012

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  • Fe-doped manganese oxide redox material for thermochemical energy storage at high-temperatures 査読

    Nobuyuki Gokon, Aoi Nishizawa, Takehiro Yawata, Selvan Bellan, Tatsuya Kodama, Hyun Seok Cho

    AIP Conference Proceedings   2126   2019年7月

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    担当区分:筆頭著者, 責任著者   掲載種別:研究論文(国際会議プロシーディングス)  

    Fe-doped manganese oxides for solar thermochemical storage are studied using thermogravimetric reactor in a laboratory scale. The operation process of Fe-doped Mn O /Mn O redox pair for two-step thermochemical cycle are optimized from the viewpoint of redox temperatures and thermochemical storage capacity, and the impact of operation temperatures on redox performances were experimentally evaluated. In addition, the thermochemical storage potentials of some Fe-X-doped manganese oxides are examined with regards to reaction rate, short-term cycling stability, storage capacity and redox temperatures. 2 3 3 4

    DOI: 10.1063/1.5117752

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  • Thermal performance of a 30 kW fluidized bed reactor for solar gasification: A CFD-DEM study 査読

    Selvan Bellan, Tatsuya Kodama, Koji Matsubara, Nobuyuki Gokon, Hyun Seok Cho, Kousuke Inoue

    Chemical Engineering Journal   1287 - 1300   2019年3月

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    掲載種別:研究論文(学術雑誌)  

    Gasification of carbonaceous materials using concentrated solar thermal radiation has been considered as one of the promising renewable pathways to produce syngas. In this study, thermal performance of a recently developed solar thermochemical reactor is presented. To analyze the gas–solid flow and heat transfer characteristics of the reactor, a transient three dimensional numerical model has been developed using discrete element method and computational fluid dynamics. Particle collision dynamics has been solved by the spring-dashpot model based on the soft-sphere method. To perform model verification, experiments have been performed using 30kW fluidized bed reactor prototype under high flux solar simulator. The particulate and thermal characteristics of spout, annulus and fountain of the fluidized bed are analyzed for different irradiation power, loaded powder and gas flow rates. The results indicate that large and small size particles govern the bottom and fountain part of the bed respectively due to gravitational force, and the peak temperature is moved from fountain core to the fountain periphery of the bed when increasing the gas flow rate. th

    DOI: 10.1016/j.cej.2018.10.111

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  • Thermochemical behavior of perovskite oxides based on LaxSr1-x(Mn, Fe, Co)O3-δ and BaySr1-yCoO3-δ redox system for thermochemical energy storage at high temperatures 査読

    Nobuyuki Gokon, Takehiro Yawata, Selvan Bellan, Tatsuya Kodama, Hyun-Seok Cho

    Energy   171   971 - 980   2019年3月

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    担当区分:筆頭著者, 責任著者   記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.energy.2019.01.081

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  • Development of a 5kWth internally circulating fluidized bed reactor containing quartz sand for continuously-fed coal-coke gasification and a beam-down solar concentrating system 査読

    Nobuyuki Gokon, Satoshi Kumaki, Yosuke Miyaguchi, Selvan Bellan, Tatsuya Kodam, Hyunseok Cho

    Energy   166   1 - 16   2019年

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    担当区分:筆頭著者, 責任著者   記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.energy.2018.10.036

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  • Particle fluidized bed receiver/reactor with a beam-down solar concentrating optics: Performance test of two-step water splitting with ceria particles using 30-kW<inf>th</inf> sun-simulator

    Tatsuya Kodama, Nobuyuki Gokon, Hyun Seok Cho, Selvan Bellan, Koji Matsubara, Kousuke Inoue

    AIP Conference Proceedings   2033   2018年11月

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    掲載種別:研究論文(国際会議プロシーディングス)  

    The first performance test of a novel windowed solar fluidized bed reactor was carried out for a two-step water splitting cycle with ceria particles by using a 30-kW sun-simulator. O and H were successfully produced by the reactor system. During the thermal reduction step of the two-step water splitting, a fluidized bed of ceria particles was created by passing N gas through the perforated bottom plate of the reactor, and about 30 kW of high flux visible light from 19 xenon-arc lamps of the sun-simulator was directed inside the reactor through a quartz window to directly irradiate the top of the fluidized bed. The central bed temperature reached the temperature of 1400 to 1500°C in the thermal reduction step. The subsequent water decomposition or hydrolysis step was performed at the central bed temperature of 800 - 900°C. About 6 - 12 Ndm of hydrogen was produced by one cycle. th 2 2 2 th 3

    DOI: 10.1063/1.5067143

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  • Numerical and experimental study on granular flow and heat transfer characteristics of directly-irradiated fluidized bed reactor for solar gasification 査読

    Selvan Bellan, Nobuyuki Gokon, Koji Matsubara, Hyun Seok Cho, Tatsuya Kodama

    International journal of hydrogen energy   43 ( 34 )   1 - 15   2018年8月

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    掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.ijhydene.2018.06.033

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  • A CFD-DEM study of hydrodynamics with heat transfer in a gas-solid fluidized bed reactor for solar thermal applications 査読

    Selvan Bellan, Koji Matsubara, Hyun Seok Cho, Nobuyuki Gokon, Tatsuya Kodama

    INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER   116   377 - 392   2018年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The particles flow and heat transfer characteristics of a high temperature solar thermochemical fluidized bed reactor have been studied for solar beam-down concentrating systems. A numerical model has been developed by the combined approach of computational fluid dynamics (CFD) and discrete element method (DEM) collisional model since it is an effective approach for studying the gas-solid flow. The discrete ordinate model has been used to solve the radiation heat transfer. An experimental visualization of particles circulation pattern and mixing of two-tower fluidized bed system has been presented. A good agreement has been found between the experimental measurements and numerical predictions. The effect of gas superficial velocity, bed mass and inlet gas temperature on the flow pattern and temperature characteristics of the bed have been investigated. The results showed that the maximum and average temperature of the bed, depends on the top layer position and focal point of the concentrated radiation, decreased when increasing the total mass of the bed. (C) 2017 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.ijheatmasstransfer.2017.09.015

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  • Heat transfer analysis of 5kWth circulating fluidized bed reactor for solar gasification using concentrated Xe light radiation 査読

    Selvan Bellan, Nobuyuki Gokon, Koji Matsubara, Hyun Seok Cho, Tatsuya Kodama

    Energy   160   245 - 256   2018年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.energy.2018.06.212

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  • Reactivity of Mn-Doped Ceria for a Thermochemical Two-Step Water-splitting cycle at low temperature 査読

    Enzo Shida, Kiko Naito, Tsuyoshi Hatamachi, Selvan Bellan, Cho Hyun-Seok, Nobuyuki Gokon, Tatsuya Kodama

    The 6th International Symposium on Fusion Technology, Niigata University, Niigata, Japan, January 26-28, 2018.   2018年

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    担当区分:責任著者   記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • Thermochemical test of quartz window type fluidized bed solar reactor by 30 kW sun simulator 査読

    Kosuke Inoue, Kazuya Senuma, Tsuyoshi Hatamachi, Hyun Seok Cho, Selvan Bellen, Nobuyuki Gokon, Tatsuya Kodama

    The 6th International Symposium on Fusion Technology, Niigata University, Niigata, Japan, January 26-28, 2018.   2018年

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    担当区分:責任著者   記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • Research on thermal charge / discharge cyclic performance of new thermal storage materials for solar thermal power generation 査読

    Asato Shirai, Mami Kaneko, Selvan Bellan, Hyun Seok Cho, Tsuyoshi Hatamachi, Nobuyuki Gokon, Tatsuya Kodama

    The 6th International Symposium on Fusion Technology, Niigata University, Niigata, Japan, January 26-28, 2018.   2018年

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    担当区分:責任著者   記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • Solar gasification of coals by a windowed fluidized bed reactor with beam-down optics 査読

    Shimpei Takagi, T. Hatamachi, S.Vellan, C. Hyunseok, N. Gokon, T. Kodama

    The 6th International Symposium on Fusion Technology, Niigata University, Niigata, Japan, January 26-28, 2018.   2018年

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    担当区分:責任著者   記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • Thermochemical tewo-step water-splitting cyclew of the CeO2/MPSZ ractive foam device by the high temperature solar furnace 査読

    Issei Tsuruma, Manami Ymada, Hun-Seok Cho, Nobuyuki Gokon, Tatsuya Kodama

    The 6th International Symposium on Fusion Technology, Niigata University, Niigata, Japan, January 26-28, 2018.   2018年

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    担当区分:責任著者   記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • Study on the reactivity of perovskite oxides in thermochemical storage cycle 査読

    Takehiro Yawata, Tsuyoshi Hatamachi, Vellan Selvan, Hunseok Cho, Tatsuya Kodama, Nobuyuki Gokon

    The 6th International Symposium on Fusion Technology, Niigata University, Niigata, Japan, January 26-28, 2018.   2018年

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    担当区分:責任著者   記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • Development of Thermochemical Two-Step Water Splitting Cycle of the CeO2/M-CeO2 Foam Device by the 3 kW Sun-simulator 査読

    Hyun-Seok Cho, Issei Tsuruma, Manami Yamada, Tatsuya Kodama, Nobuyuki Gokon

    The 6th International Symposium on Fusion Technology, Niigata University, Niigata, Japan, January 26-28, 2018.   2018年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • Particles Fluidized Bed Receiver/Reactor with a Beam-Down Solar Concentrating Optics: First Performance Test on Two-Step Water Splitting with Ceria Using a Miyazaki Solar Concentrating System 査読

    Tatsuya Kodama, Nobuyuki Gokon, Hunseok Cho, Selvan Bellan

    SolarPACES 2018, Casabranca, Morocco, October 2-5, 2018   2018年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • Fe-doped Mn2O3/Mn3O4 redox material for thermochemical energy storage at high-temperatures 査読

    Nobuyuki Gokon, Aoi Nishizawa, Takehiro Yawata, Hyun-seok Cho, Selvan Bellan, Tatsuya Kodama

    SolarPACES 2018, Casabranca, Morocco, October 2-5, 2018   2018年

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    担当区分:筆頭著者, 責任著者   記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • Heat transfer and fluid flow analysis of a fluidized bed reactor for beam-down optics 査読

    Selvan Bellan, Tatsuya Kodama, Koji Matsubara, Nobuyuki Gokon, Hyun Seok Cho

    SolarPACES 2018, Casabranca, Morocco, October 2-5, 2018   2018年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • Conjugated radiation-convection-conduction heat transfer analysis of volumetric receiver with highly concentrated radiation

    Mitsuho Nakakura, Selvan Bellan, Hyun-Seok Cho, Koji Matsubara, Nobuyuki Gokon, Tatsuya Kodama

    International Heat Transfer Conference   2018-   7866 - 7873   2018年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:Begell House Inc.  

    This study focuses on the conjugate radiation-convection-conduction heat-transfer problem for a square channel of volumetric solar receiver with concentrated irradiation for Concentrated Solar Power (CSP). A single channel of a honeycomb receiver is directly irradiated from the outside, via a transparent wall. Atmospheric air flows through the channel and absorbs the sensible heat. Governing equations are continuity, Navier-Stokes and energy equations for solid/fluid region, and radiative transfer equation. Radiation was solved by the Discrete Ordinates (DO) model. The effects of the number of mesh grids and direction vectors on the DO model were confirmed to be negligible. This study analyzed the heat-transfer performance of stainless-steel receivers with different channel geometry. Three different types and sizes of channels were treated
    L-shaped cuts were made at the channel top. The heat transfer performance of these channels, i.e. bulk air temperature and pressure drop at the outlet were improved by the L-shape cutting. The wall heat flux difference between simple and cut channel was clarified by the contour plots of inner walls. Across the entire inner wall, the conduction heat flux contributed to the heating of the flowing air, while the radiation heat-flux dominated near the inlet due to high incident radiation. As a result, the wall heat-flux had characteristic profile along the channel depth (-z) direction. This study elucidates conjugate heat transfer mechanism in the honeycomb-like channel receivers with highly concentrated radiation.

    DOI: 10.1615/ihtc16.nee.023436

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  • Gas-solid flow and heat transfer characteristics of a fluidized bed reactor for solar thermal applications

    Selvan Bellan, Koji Matsubara, Nobuyuki Gokon, Tatsuya Kodama, Hyun Seok Cho, Issei Tsuchida

    International Heat Transfer Conference   2018-   6519 - 6527   2018年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:Begell House Inc.  

    In concentrated solar thermal industry, fluidized-bed technology has been used to produce hydrogen and synthetic gas by two-step water splitting cycles and gasification of coal cokes respectively. A two tower fluidized bed reactor has been developed in this study for solar thermochemical conversions. To study the granular flow and heat transfer characteristics of the two tower fluidized bed reactor, a numerical model has been developed by combined approach of discrete element method and computational fluid dynamics. Particle collision dynamics has been solved by the spring-dashpot model based on the soft-sphere method. Discrete ordinate radiation model has been used to solve the radiative transfer equation. To validate the model, the predicted heat transfer characteristics of the bed have been compared with the reported experimental data. A reasonable agreement has been found between the predicted and experimental results. Particulate flow dynamics of the bed filled with ceria powder is presented with temperature distributions. Using this model, the key operating parameters can be optimized.

    DOI: 10.1615/ihtc16.mpf.023665

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  • Buoyancy-opposed volumetric solar receiver with beam-down optics irradiation 査読

    Mitsuho Nakakura, Koji Matsubara, Hyun-Seok Cho, Tatsuya Kodama, Nobuyuki Gokon, Selvan Bellan, Kazuo Yoshida

    Energy   141   2337 - 2350   2017年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Elsevier Ltd  

    This paper describes a volumetric solar receiver that is vertically integrated with beam-down optics for condensed light irradiation. The heat-transfer performance of a silicon carbide honeycomb receiver was investigated using a 30-kWth solar simulator and numerical simulation. The experiments achieved an air temperature of 840 K at the receiver outlet by varying the operational parameters. Numerical simulations were performed for a vertical honeycomb block with beam-down irradiation and a horizontal honeycomb block with tower-type irradiation to elucidate the effects of buoyancy. Three blocks with different sizes were simulated for a variety of operational parameters. When the block was oriented vertically, the flow and temperature fields remained nearly symmetric in and near the receiver. In contrast, when it was oriented horizontally, the flow and temperature became asymmetric, with the hot spot moving toward the receiver's side wall and the stream in the receiver being reversed. The vertical orientation's robustness to buoyancy effects prevented any reduction in the receiver efficiency or outlet temperature and suppressed the thermal leakage.

    DOI: 10.1016/j.energy.2017.11.147

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  • Particle reactors for solar thermochemical processes 査読

    Tatsuya Kodama, Selvan Bellan, Nobuyuki Gokon, Hyun Seok Cho

    SOLAR ENERGY   156   113 - 132   2017年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Utilization of solar thermal power for high temperature fuel production has the potential to significantly reduce the fossil fuel dependence of our current economy. Over the past two decades, remarkable progress has been made in the development of solar driven thermochemical reactors for the production of hydrogen and syngas as they are promising energy carriers for transportation, domestic and industrial applications. However, there are solar peculiarities in comparison to conventional thermochemical processes high thermal flux density and frequent thermal transients because of the fluctuating insolation-, and conventional industrial thermochemical reactors are generally not suitable for solar driven reactors. Therefore, solar-specific modifications of reactor design are necessary to realize efficient solar driven thermochemical processes. In solar thermochemical reactors, the methods for solar-heating particulate solid feedstock to high temperatures can be broadly classified as solar "directly" and "indirectly" absorbing reactors. On solar thermochemical processes involving reacting solid particles at high temperatures, such as "solar two-step water splitting with metal oxides" and "solar gasification", various types of solar directly and indirectly absorbing particle reactors have been developed. In this review, recent development of solar particle reactors for the above solar thermochemical processes is described. (C) 2017 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.solener.2017.05.084

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  • CFD-DEM investigation of particles circulation pattern of two-tower fluidized bed reactor for beam-down solar concentrating system 査読

    Selvan Bellan, Koji Matsubara, Cho Hyun Cheok, Nobuyuki Gokon, Tatsuya Kodama

    POWDER TECHNOLOGY   319   228 - 237   2017年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE BV  

    In this study, a numerical model has been developed by the combined approach of computational fluid dynamics (CFD) and discrete element method (DEM) collisional model to study the particle-fluid flow of the fluidized bed reactor for solar beam-down concentrating system. The contact forces between the particles have been calculated by the spring-dashpot model, based on the soft-sphere method. An experimental visualization of particles circulation pattern and mixing of two-tower fluidized bed system has been presented. A good agreement has been found between the experimental measurements and numerical predictions. To investigate the influence of fluid flow rate and particle size on the flow pattern of the reactor, simulations have been performed for various conditions. The results indicate that the large size particles induce three-dimensional effects as they are accumulated at the central axis region. The average bed height of the left tower increased by 23.4% when increasing the flow rate about 70%. (C) 2017 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.powtec.2017.06.060

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  • CFD-DEM Investigation on Flow and Temperature Distribution of Ceria Particles in a Beam-Down Fluidized Bed Reactor 査読

    Selvan Bellan, Koji Matsubara, Hyun Seok Cho, Nobuyuki Gokon, Tatsuya Kodama

    SolarPACES 2017, Santiago, Chili, September 26-29, 2017   2017年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • THERMOCHEMICAL TWO-STEP WATER-SPLITTING USING PEROVSKITE OXIDE FOR SOLAR HYDROGEN PRODUCTION 査読

    Yuta Sugiyama, Nobuyuki Gokon, Hyun-Seok Cho, Selvan Bellan, Tsuyoshi Hatamachi, Tatsuya Kodama

    Asian Conference on thermal sciences 2017, ICC JEJU, JEJU ISLAND, KOREA, March 26-30, 2017.   2017年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • HYDROGEN PRODUCTIVITY AND REPEATABILITY FOR THERMOCHEMICAL TWO-STEP WATER-SPLITTING CYCLE USING MN-DOPED CERIUM OXIDES 査読

    Kiko Naito, Nobuyuki Gokon, Hyun-Seok Cho, Selvan Bellan, Tsuyoshi Hatamachi, Tatsuya Kodama

    Asian Conference on thermal sciences 2017, ICC JEJU, JEJU ISLAND, KOREA, March 26-30, 2017.   2017年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • SOLAR RECEIVER/REACTOR OF FLUIDIZED BED WITH MIYAZAKI BEAM-DOWN SOLAR CONCENTRATING SYSTEM 査読

    Kazuya Senuma, Nobuyuki Gokon, Hyun-Seok Cho, Selvan Bellan, Tsuyoshi Hatamachi, Tatsuya Kodama

    Asian Conference on thermal sciences 2017, ICC JEJU, JEJU ISLAND, KOREA, March 26-30, 2017.   2017年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • Investigation of reaction temperature of cerium oxide in two-step carbon dioxide splitting cycles 査読

    Kazuya Senuma, Nobuyuki Gokon, Hyun-Seok Cho, Selvan Bellan, Tsuyoshi Hatamachi, Tatsuya Kodama

    Asian Conference on thermal sciences 2017, ICC JEJU, JEJU ISLAND, KOREA, March 26-30, 2017.   2017年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • HEAT TRANSFER ANALYSIS OF AN OVAL CERAMIC CONTAINER ENCAPSULATED BY PHASE CHANGE MATERIAL FOR THERMAL ENERGY STORAGE SYSTEM 査読

    Selvan Bellan, Shunichi Tazawa, Tomohiro Nakamata, Cho Hyun Cheok, Nobuyuki Gokon, Koji Matsubara, Tatsuya Kodama

    Asian Conference on thermal sciences 2017, ICC JEJU, JEJU ISLAND, KOREA, March 26-30, 2017.   2017年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • NUMERICAL SIMULATION OF VOLUMETRIC AIR RECEIVER FOR BEAM DOWN REFLECTOR 査読

    M. Nakakura, K. Matsubara, S. Kawagoe, S. Bellan, H. S. Cho, N. Gokon, T. Kodama

    Asian Conference on thermal sciences 2017, ICC JEJU, JEJU ISLAND, KOREA, March 26-30, 2017.   2017年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • Melting process of PCM in ceramic capsule for solar thermal storage 査読

    Selvan Bellan, Shunichi Tazawa, Koji Matsubara, Cho Hyun Seok, Nobuyuki Gokon, Tatsuya Kodama

    SOLARIS Conference 27 - 28 Jul 2017, London, UK.   2017年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • Heat Transfer Analysis of Fluidized Bed Particle Receiver for High-Temperature Solar Concentration 査読

    Koji Matsubara, Atsushi Sakurai, Takahiro Suzuki, Selvan Bellan, Nobuyuki Gokon, Cho Hyun-Seok, Tatsuya Kodama

    SOLARIS Conference 27 - 28 Jul 2017, London, UK   2017年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • Discrete ordinates simulation of volumetric solar receiver with beam-down irradiation and its verification using big sun simulator 査読

    Mitsuho Nakakura, Koji Matsubara, Yuki Aoki, Selvan Bellan, Cho Hyun-Seok, Nobuyuki Gokon, Tatsuya Kodama

    SOLARIS Conference 27 - 28 Jul 2017, London, UK   2017年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • Preliminary Tests of Batch Type Fluidized Bed Reactor for Development of Continuously-Feeding Fluidized Bed Reactor - an Elevated Temperature and Gasification Processes ? 査読

    Nobuyuki Gokon, Shinpei Takagi, Hyun-seok Cho, Selvan Bellan, Tatsuya Kodama

    SolarPACES 2017, Santiago, Chili, September 26-29, 2017   2017年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • Thermal Storage/Discharge Performances of Cu-Si Alloy for Solar Thermochemical Process 査読

    Nobuyuki Gokon, Tomoya Yamaguchi, Hyun-seok Cho, Selvan Bellan, Tsuyoshi Hatamachi, Tatsuya Kodama

    INTERNATIONAL CONFERENCE ON CONCENTRATING SOLAR POWER AND CHEMICAL ENERGY SYSTEMS (SOLARPACES 2016)   1850   2017年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:AMER INST PHYSICS  

    The present authors (Niigata University, Japan) have developed a tubular reactor system using novel "double-walled" reactor/receiver tubes with carbonate molten-salt thermal storage as a phase change material (PCM) for solar reforming of natural gas and with Al-Si alloy thermal storage as a PCM for solar air receiver to produce high-temperature air. For both of the cases, the high heat capacity and large latent heat (heat of solidification) of the PCM phase circumvents the rapid temperature change of the reactor/receiver tubes at high temperatures under variable and uncontinuous characteristics of solar radiation. In this study, we examined cyclic properties of thermal storage/discharge for Cu-Si alloy in air stream in order to evaluate a potentiality of Cu-Si alloy as a PCM thermal storage material. Temperature-increasing performances of Cu-Si alloy are measured during thermal storage (or heat-charge) mode and during cooling (or heat-discharge) mode. A oxidation state of the Cu-Si alloy after the cyclic reaction was evaluated by using electron probe micro analyzer (EPMA).

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  • Numerical Analysis of Fluid Flow and Heat Transfer During Melting Inside a Cylindrical Container for Thermal Energy Storage System 査読

    Selvan Bellan, Cho Hyun Cheok, Nobuyuki Gokon, Koji Matsubara, Tatsuya Kodama

    INTERNATIONAL CONFERENCE ON CONCENTRATING SOLAR POWER AND CHEMICAL ENERGY SYSTEMS (SOLARPACES 2016)   1850   2017年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:AMER INST PHYSICS  

    This paper presents a numerical analysis of unconstrained melting of high temperature(&gt;1000K) phase change material (PCM) inside a cylindrical container. Sodium chloride and Silicon carbide have been used as phase change material and shell of the capsule respectively. The control volume discretization approach has been used to solve the conservation equations of mass, momentum and energy. The enthalpy-porosity method has been used to track the solidliquid interface of the PCM during melting process. Transient numerical simulations have been performed in order to study the influence of radius of the capsule and the Stefan number on the heat transfer rate. The simulation results show that the counter-clockwise Buoyancy driven convection over the top part of the solid PCM enhances the melting rate quite faster than the bottom part.

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  • Particles Fluidized Bed Receiver/Reactor Tests with Quartz Sand Particles Using a 100-kW(th) Beam-Down Solar Concentrating System at Miyazaki 査読

    Tatsuya Kodama, Nobuyuki Gokon, Hyun Seok Cho, Koji Matsubara, Hiroshi Kaneko, Kazuya Senuma, Sumie Itoh, Shin-nosuke Yokota

    INTERNATIONAL CONFERENCE ON CONCENTRATING SOLAR POWER AND CHEMICAL ENERGY SYSTEMS (SOLARPACES 2016)   1850   2017年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:AMER INST PHYSICS  

    A window-type, solar fluidized bed receiver with quartz sand particles was tested by a 100-kWth novel beam-down solar concentrating system at Miyazaki, Japan. A compound parabolic concentrator (CPC) was placed above the quartz window of the receiver to increase the concentration of the solar fluxes from the beam-down solar concentrating system. The solar tests were performed in the middle of December, 2015. The central bed temperature of the receiver was reached around 960-1100 degrees C. It was found that only 20 Ndm(3)/min of air flow rate was enough to create the uniform fluidization of the particles at the given temperature range. It was predicted that if the central bed temperature could have been higher than 1100 degrees C if solar receiver test had conducted in other seasons than winter. The next solar campaign of the receiver test will be carried out in October, 2016.

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  • Development and Experimental Study for Hydrogen Production from the Thermochemical Two-step Water Splitting Cycles with a CeO2 Coated New Foam Device Design Using Solar Furnace System 査読

    Hyun Seok Cho, Tatsuya Kodama, Nobuyuki Gokon, Jong Kyu Kim, Sang Nam Lee, Yong Heack Kang

    INTERNATIONAL CONFERENCE ON CONCENTRATING SOLAR POWER AND CHEMICAL ENERGY SYSTEMS (SOLARPACES 2016)   1850   2017年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:AMER INST PHYSICS  

    A solar reactor containing a CeO2-coated reactive foam device for producing hydrogen via a thermochemical two-step water splitting cycle was proposed and experimentally tested. Modeling of the optical properties of the 40 kW(th) KIER (Korea Institute of Energy Research) solar furnace was performed to design and prepare the optimized foam matrix shape and the new solar reactor. Solar demonstration of the solar reactor was accomplished in the KIER 40 kW(th) solar furnace and hydrogen was produced successfully during the water decomposition step. The conical shape foam device was suggested and tested the temperature gradients and hydrogen productivity. Finally, five cyclic test was conducted with the conical shape CeO2-coated foam device, the total hydrogen production was 1394.32 Ncm(3) during the five cycles and the average hydrogen production per cycle was 278.86 Ncm(3).

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  • 4-5-4 化学蓄熱サイクルにおけるペロブスカイト系酸化物の反応性に関する研究

    中村 彰兵, 江田 俊介, 籏町 剛, 郷右近 展之, 児玉 竜也, 児玉 竜也

    日本エネルギー学会大会講演要旨集   26   176 - 177   2017年

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    記述言語:日本語   出版者・発行元:一般社団法人日本エネルギー学会  

    <p>Perovskite-type metal oxides were synthesized by Pechini method. Then, they were examined its reduction/oxidation reactivity by thermogravimetric analysis. After TGA testing, high redox-capacity materials were selected, and its reaction enthalpy was measured by DSC analysis. These results showed that the redox reactivity was improved by decreasing Lanthanum ion activity and increasing Barium ion concentration of samples. It was revealed that Ba-containing samples are potential thermochemical energy storage application.</p>

    DOI: 10.20550/jietaikaiyoushi.26.0_176

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  • 4-5-2 30kWサンシミュレータによる石英窓型流動層式ソーラー反応器の水熱分解試験

    井上 紘輔, 瀬沼 和也, 籏町 剛, 曺 賢石, BELLEN Selvan, 郷右近 展之, 児玉 竜也, 金子 宏

    日本エネルギー学会大会講演要旨集   26   172 - 173   2017年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本エネルギー学会  

    <p>Mitaka Koki Co., LTd., Miyazaki prefecture, Miyazaki University and Niigata University build a beam-down (BD) solar concentrating system in August 2012 at Miyazaki University for solar demonstration of the receiver/reactor. Both universities started an R&D joint project since 2011 to demonstrate the up-scaled receiver/reactor under a concentrated solar radiation. Niigata University has a 30 kW sun-simulator for testing of solar reactor. In this study, the first results of the receiver/reactor using 30 kW sun-simulator are reported. Quartz sand is used as a fluidization particle to examine performances of the receiver/reactor, while air is used as a passing gas. The temperatures of air and quartz sand are shown in the paper. In addition, cerium oxide powder is used as a fluidization/reaction particle to perform thermochemical two-step water-splitting cycle. The oxygen and hydrogen production are reported in this paper.</p>

    DOI: 10.20550/jietaikaiyoushi.26.0_172

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  • Cyclic thermal storage/discharge performances of a hypereutectic Cu-Si alloy under vacuum for solar thermochemical process 査読

    Nobuyuki Gokon, Tomoya Yamaguchi, Tatsuya Kodama

    ENERGY   113   1099 - 1108   2016年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    A copper-silicon alloy (Cu-Si alloy) was examined and evaluated as a phase-change material (PCM) for thermal energy storage applications such as load shaving and peak load shifting when coupled to a solar thermochemical reactor, reformer, or gasifier for the production of solar fuel. The Cu-Si alloy was selected as a high-temperature PCM thermal storage medium alternative to molten carbonate salts, and the compatibility of this alloy with a graphite-carbon encapsulation material was experimentally examined. The cyclic thermal storage/discharge properties of the Cu-Si alloy as a latent-heat energy storage material were studied with respect to thermal cycles. A thermal stability test was performed on Cu-20 wt% Si, Cu-25 wt% Si, and Cu-30 wt% Si alloys placed in a graphite container under vacuum. The performances of the Cu-Si alloys with increasing and decreasing temperature were measured during the thermal storage (heat-charge) and cooling (heat-discharge) modes, respectively. The elemental distribution of each Cu-Si alloy after the cyclic reaction was evaluated using an electron probe microanalyzer (EPMA). The heat storage capacities before and after the cyclic reaction were evaluated using differential scanning calorimetry (DSC) and were compared to the thermal storage properties of the molten carbonate salt. (C) 2016 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.energy.2016.07.005

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  • Cyclic thermal storage/discharge performances of hypereutectic alloy for solar latent heat storage 査読

    Tomoya Yamaguchi, Nobuyuki Takahashi, Tsuyoshi Hatamachi, Hyun-Seok Cho, Nobuyuki Gokon, Tatsuya Kodama

    International Symposium on Fusion Tech 2016, Harbin Institute of Technology, Harbin, China, January 19-21, 2016.   2016年

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  • Particles Fluidized Bed Receiver/Reactor with a Beam-Down Solar Concentrating Optics: 30-kW(th) Performance Test Using a Big Sun-Simulator 査読

    Tatsuya Kodama, Nobuyuki Gokon, Hyun Seok Cho, Koji Matsubara, Tetsuro Etori, Akane Takeuchi, Shin-nosuke Yokota, Sumie Ito

    SOLARPACES 2015: INTERNATIONAL CONFERENCE ON CONCENTRATING SOLAR POWER AND CHEMICAL ENERGY SYSTEMS   1734   2016年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:AMER INST PHYSICS  

    A novel concept of particles fluidized bed receiver/reactor with a beam-down solar concentrating optics was performed using a 30-kW(th) window type receiver by a big sun-simulator. A fluidized bed of quartz sand particles was created by passing air from the bottom distributor of the receiver, and about 30 kW(th) of high flux visible light from 19 xenon-arc lamps of the sun-simulator was directly irradiated on the top of the fluidized bed in the receiver through a quartz window. The particle bed temperature at the center position of the fluidized bed went up to a temperature range from 1050 to 1200 degrees C by the visible light irradiation with the average heat flux of about 950 kW/m(2), depending on the air flow rate. The output air temperature from the receiver reached 1000 - 1060 degrees C.

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  • Particles Fluidized Bed Receiver/Reactor with a Beam-Down Solar Concentrating Optics: 30-kW(th) Performance Test Using a Big Sun-Simulator 査読

    Tatsuya Kodama, Nobuyuki Gokon, Hyun Seok Cho, Koji Matsubara, Tetsuro Etori, Akane Takeuchi, Shin-nosuke Yokota, Sumie Ito

    SOLARPACES 2015: INTERNATIONAL CONFERENCE ON CONCENTRATING SOLAR POWER AND CHEMICAL ENERGY SYSTEMS   1734   2016年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:AMER INST PHYSICS  

    A novel concept of particles fluidized bed receiver/reactor with a beam-down solar concentrating optics was performed using a 30-kW(th) window type receiver by a big sun-simulator. A fluidized bed of quartz sand particles was created by passing air from the bottom distributor of the receiver, and about 30 kW(th) of high flux visible light from 19 xenon-arc lamps of the sun-simulator was directly irradiated on the top of the fluidized bed in the receiver through a quartz window. The particle bed temperature at the center position of the fluidized bed went up to a temperature range from 1050 to 1200 degrees C by the visible light irradiation with the average heat flux of about 950 kW/m(2), depending on the air flow rate. The output air temperature from the receiver reached 1000 - 1060 degrees C.

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  • Experimental Demonstration and Numerical Model of a Point Concentration Solar Receiver Evaluation System Using a 30 kWth Sun Simulator 査読

    M. Nakakura, M. Ohtake, K. Matsubara, K. Yoshida, H. S. Cho, T. Kodama, N. Gokon

    SOLARPACES 2015: INTERNATIONAL CONFERENCE ON CONCENTRATING SOLAR POWER AND CHEMICAL ENERGY SYSTEMS   1734   2016年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:AMER INST PHYSICS  

    In 2014, Niigata University and the Institute of Applied Energy developed a point-concentration receiver-evaluation system using a silicon carbide (SiC) honeycomb and a three-dimensional simulation method. The system includes several improvements over its forerunner, including the ability to increase/decrease the power-on aperture (POA), air-mass flow-rate (AMF) and the height of the focal surface. This paper will focus on the results of tests using an improved receiver evaluation system, at a focal height of 1600 mm. Maximum outlet air temperature reached as high as 800 K, but exerted no untoward effects on the system. Also, receiver efficiency rated between 45 % and 70 %, according to POA. A numerical, 3D method of analysis was created at the same time, in order to analyze temperature and flow-distribution, in detail. This simulation, based on the dual-cell approach, reproduced the thermal non-equilibrium between the solid and fluid domain of the receiver material. The most interesting feature of this simulation, is that, because it includes upper and lower computational domains, it can be used to analyze the influence of both inward-and outward-flowing receiver materials.

    DOI: 10.1063/1.4949078

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  • Synthesis of CeO2 particles by spray dryer method for solar hydrogen production 査読

    Sumie Ito, Shiori Abe, Tsuyoshi Hatamachi, Cho Hyunseok, Nobuyuki Gokon, Tatsuya Kodama

    International Symposium on Fusion Tech 2016, Harbin Institute of Technology, Harbin, China, January 19-21, 2016.   2016年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • Cold Test with a Benchtop Set-up for Fluidized Bed Reactor Using Quartz Sand to Simulate Gasification of Coal Cokes by Concentrated Solar Radiation 査読

    Nobuyuki Gokon, Tomoaki Tanabe, Tadaaki Shimizu, Tatsuya Kodama

    SOLARPACES 2015: INTERNATIONAL CONFERENCE ON CONCENTRATING SOLAR POWER AND CHEMICAL ENERGY SYSTEMS   1734   2016年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:AMER INST PHYSICS  

    The impacts of internal circulation of a mixture of coal-coke particles and quartz sand on the fluidization state in a fluidized bed reactor are investigated by a cold test with a benchtop set-up in order to design 10-30 kWth scale prototype windowed fluidized-bed reactor. Firstly, a basic relationship between pressure loss of inlet gas and gas velocity was experimentally examined using quartz sand with different particle sizes by a small-scale quartz tube with a distributor at ambient pressure and temperature. Based on the results, an appropriate particle range of quartz sand and layer height/layer diameter ratio (L/D ratio) was determined for a design of the fluidized bed reactor. Secondly, a windowed reactor mock-up was designed and fabricated for solar coke gasification using quartz sand as a bed material. The pressure loss between the inlet and outlet gases was examined, and descending cokes and sand particles on the sidewall of the reactor was observed in the reactor mock-up. The moving velocity and distance of descending particles/sands from the top to bottom of fluidized bed were measured by the visual observation of the colored tracer particles on outside wall of the reactor.

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  • 4-3-3 宮崎ビームダウン太陽集光システムによる石英窓型粒子流動層式ソーラーレシーバー/反応器の開発

    瀬沼 和也, 横田 伸乃資, 伊藤 澄江, 曺 賢石, 籏町 剛, 郷右近 展之, 児玉 竜也, 金子 宏

    日本エネルギー学会大会講演要旨集   25   136 - 137   2016年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本エネルギー学会  

    <p>Mitaka Koki Co., LTd., Miyazaki prefecture, Miyazaki University and Niigata University build a beam-down (BD) solar concentrating system in August 2012 at Miyazaki University for solar demonstration of the receiver/reactor. Both universities started an R&D joint project since 2011 to demonstrate the up-scaled receiver/reactor under a concentrated solar radiation. In this study, the first demonstration results of the receiver/reactor using BD solar concentrating system are reported. Quartz sand is used as a fluidization particle to examine performances of the receiver/reactor, while air is used as a passing gas. The temperatures of air and quartz sand are shown in the paper.</p>

    DOI: 10.20550/jietaikaiyoushi.25.0_136

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  • 4-3-1 他金属ドープセリアの二段階水熱分解サイクルの高活性化に関する研究

    内藤 喜子, 籏町 剛, 郷右近 展之, 児玉 竜也

    日本エネルギー学会大会講演要旨集   25   132 - 133   2016年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本エネルギー学会  

    <p>Solar hydrogen production via thermochemical water-splitting cycle by concentrated high-temperature heat has extensively investigated in a world. In this study, a thermochemical two-step water-splitting using redox material of Mn doped-ceria powder was examined in consecutive thermal reduction-decomposition steps by switching a passing gas from high purity Nitrogen in the TR step into the gas mixture of N2 and steam in the WD step. The reactivity of Mn doped-ceria powder with 5-30 mol% Mn doping was evaluated in this study.</p>

    DOI: 10.20550/jietaikaiyoushi.25.0_132

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  • 4-3-2 LaSrAlMnO<sub>3-δ</sub>の二段階水熱分解サイクルにおける反応性に関する研究

    杉山 雄太, 籏町 剛, 郷右近 展之, 児玉 竜也

    日本エネルギー学会大会講演要旨集   25   134 - 135   2016年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本エネルギー学会  

    <p>Perovskite oxide powder was examined as a redox material on reactivity of thermochemical two-step water-splitting for converting high-temperature heat into chemical fuels. In this study, in order to examine reactivity of the redox material at lower temperature in the thermochemical two-step water-splitting cycle, the amount of oxygen and hydrogen, its stoichiometry were investigared using LaSrAlMnO<sub>3-δ</sub> powder at thermal reduction temperature of 1350 °C and water-decomposition temperture of 1000 °C.</p>

    DOI: 10.20550/jietaikaiyoushi.25.0_134

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  • Oxygen and hydrogen productivities and repeatable reactivity of 30-mol%-Fe-, Co-, Ni-, Mn-doped CeO2?δ for thermochemical two-step water-splitting cycle 査読

    Nobuyuki Gokon, Toshinori Suda, Tatsuya Kodama

    Energy   90   1280 - 1289   2015年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.energy.2015.06.085

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  • Thermochemical reactivity of 5-15 mol% Fe, Co, Ni, Mn-doped cerium oxides in two-step water-splitting cycle for solar hydrogen production 査読

    Nobuyuki Gokon, Toshinori Suda, Tatsuya Kodama

    THERMOCHIMICA ACTA   617 ( 10 )   179 - 190   2015年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE BV  

    The thermochemical two-step water-splitting cycle using transition element-doped cerium oxide (M CeO2-delta; M=Fe, Co, Ni, Mn) powders was studied for hydrogen production from water. The oxygen/hydrogen productivity and repeatability of M CeO2-delta materials with M doping contents in the 5-15 mol% range were examined using a thermal reduction (TR) temperature of 1500 degrees C and water decomposition (WD) temperatures in the 800-1150 degrees C range. The temperature, steam partial pressure, and steam flow rate in the WD step had an impact on the hydrogen productivity and production rate. 5 mol% Fe- and Co-doped CeO2-delta enhances hydrogen productivity by up to 25% on average compared to undoped CeO2, and shows stable repeatability of stoichiometric oxygen and hydrogen production for the cyclic thermochemical two-step water-splitting reaction. In addition, 5 mol% Mn-doped CeO2-delta, 10 and 15 mol% Fe- and Mn-doped CeO2-delta show near stoichiometric reactivities. (C) 2015 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.tca.2015.08.036

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  • Improved operation of solar reactor for two-step water-splitting H-2 production by ceria-coated ceramic foam device 査読

    H. S. Cho, N. Gokon, T. Kodama, Y. H. Kang, H. J. Lee

    INTERNATIONAL JOURNAL OF HYDROGEN ENERGY   40 ( 1 )   114 - 124   2015年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The joint international project between Niigata University (Japan) and the Korea Institute of Energy Research, KIER (Korea) on "Solar Demonstration of Water-Splitting Reactor using Ceramic Foam Device" has two goals. (1) Develop a solar reactor using reactive cerium oxide foam devices for high-temperature two-step thermochemical water-splitting cycle. (2) Test its performance under various operational methods using a 40 kW(th) solar furnace driven by natural solar energy. The reactive CeO2/MPSZ (MgO partially stabilized zirconia) foam device for two-step water-splitting was developed and prepared by Niigata University/Japan; it involves coating an inert zirconia foam matrix with reactive CeO2. In this paper, highly reactive CeO2 particles were used the redox material in CeO2/MPSZ foam devices to investigate the use of solar energy for hydrogen production. The solar-driven thermochemical two-step water-splitting cycle was demonstrated using the 40 kWth KIER solar furnace in Korea combined with the CeO2/MPSZ foam device. At the center of the foam device, temperatures were 1500 degrees C-1600 degrees C during the thermal reduction step and 600 degrees C-1100 degrees C during the subsequent water decomposition step. Hydrogen was successfully produced from the CeO2/MPSZ foam device, and profiles for hydrogen production and CeO2 conversion indicated definitely improved operations compared to earlier studies. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.ijhydene.2014.10.084

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  • Steam gasification of coal cokes by internally circulating fluidized-bed reactor by concentrated Xe-light radiation for solar syngas production 査読

    Nobuyuki Gokon, Takuya Izawa, Tatsuya Kodama

    ENERGY   79   264 - 272   2015年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    A laboratory-scale prototype windowed reactor using a fluidized bed of coal coke particles was tested for thermochemical gasification using concentrated Xe light radiation as an energy source. The fluidized-bed reactor, designed to be combined with a solar reflective tower or beam-down optics, is evaluated for steam gasification of coal coke according to gasification performance: CO, H-2, and CO2 production rates; carbon conversion; light-to-chemical efficiency. Internal circulation of coal coke particles inside the reactor increases gasification performance, which is further enhanced by higher steam partial pressure of the inlet gas. (C) 2014 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.energy.2014.11.012

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  • Development of a receiver evaluation system using 30 kWth point concentration solar simulator 査読

    M. Nakakura, M. Ohtake, K. Matsubara, K. Yoshida, H. S. Cho, T. Kodama, N. Gokon

    INTERNATIONAL CONFERENCE ON CONCENTRATING SOLAR POWER AND CHEMICAL ENERGY SYSTEMS, SOLARPACES 2014   69   497 - 505   2015年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:ELSEVIER SCIENCE BV  

    The point-concentration receiver evaluation system was developed using the world class 30 kWth light source of 19 arc xenon lamps. The system comprises of a receiver unit, heat exchanger, blower, chiller and light source. Precise measurement of the thermal power absorbed by air was performed by the enthalpy rise of the coolant water and that of the exhausted air. The experimental test was performed using silicon carbide honeycomb in order to achieve a high air temperature of 560 degrees C. The efficiency of the receiver, based on the power of the aperture, was 40% to 80%. A three-dimensional simulation based on the dual cell approach was made to reveal detailed information of the flow and temperature fields. This successfully reproduced the thermal nonequilibrium between the solid and fluid parts of the receiver. The air exit temperature and efficiency of the numerical simulation were consistent with that determined experimentally. Air was suctioned from the broad space above the receiver top surface. The adopted simulation model with the free stream was confirmed to be essential for evaluating an open loop receiver. (C) 2015 Published by Elsevier Ltd.

    DOI: 10.1016/j.egypro.2015.03.058

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  • Numerical modeling of a two-tower type fluidized receiver for high temperature solar concentration by a beam-down reflector system 査読

    K. Matsubara, H. Sakai, Y. Kazuma, A. Sakurai, T. Kodama, N. Gokon, H. S. Cho, K. Yoshida

    INTERNATIONAL CONFERENCE ON CONCENTRATING SOLAR POWER AND CHEMICAL ENERGY SYSTEMS, SOLARPACES 2014   69   487 - 496   2015年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:ELSEVIER SCIENCE BV  

    This study describes the flow and thermal field of a two-tower fluidized receiver, aimed to be incorporated into a beam-down reflector system. An experimental visualization and numerical simulation were made to accumulate phenomenological knowledge, in order to complete the design of a demonstration model. Visualization of the cold particle bed with no irradiation revealed that global circulation occurs between the two towers by the aeration with different line velocities. The numerical simulation revealed that this global circulation enhances the transport of sensible heat from the irradiated layer in the high pressure tower to the low pressure tower. The global circulation in the two-tower fluidized receiver has the potential to be extended for use in a thermal receiver and direct storage system. Unexpectedly, local circulations occur on the high and low pressure sides, and are stronger than the global circulation. These local circulations contribute to the thermal mixing in each tower. The bottom distributor on the low pressure side can cause an uprising flow which leads to the local circulation. The design of the distributor is suggested to be elaborated based on these findings. (C) 2015 The Authors. Published by Elsevier Ltd.

    DOI: 10.1016/j.egypro.2015.03.057

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  • Cold model experiments on fluidization behavior of mixture of quartz sand and coal cokes for solar gasification 査読

    Nobuyuki Gokon, Tomoaki Tanabe, Tadaaki Shimizu, Tatsuya Kodama

    SolarPACES 2015, Cape Town, South Africa, October 13-16, 2015.   2015年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • Numerical modeling of a two-tower type fluidized receiver for high temperature solar concentration by a beam-down reflector system 査読

    K. Matsubara, H. Sakai, Y. Kazuma, A. Sakurai, T. Kodama, N. Gokon, H. S. Cho, K. Yoshida

    INTERNATIONAL CONFERENCE ON CONCENTRATING SOLAR POWER AND CHEMICAL ENERGY SYSTEMS, SOLARPACES 2014   69   487 - 496   2015年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:ELSEVIER SCIENCE BV  

    This study describes the flow and thermal field of a two-tower fluidized receiver, aimed to be incorporated into a beam-down reflector system. An experimental visualization and numerical simulation were made to accumulate phenomenological knowledge, in order to complete the design of a demonstration model. Visualization of the cold particle bed with no irradiation revealed that global circulation occurs between the two towers by the aeration with different line velocities. The numerical simulation revealed that this global circulation enhances the transport of sensible heat from the irradiated layer in the high pressure tower to the low pressure tower. The global circulation in the two-tower fluidized receiver has the potential to be extended for use in a thermal receiver and direct storage system. Unexpectedly, local circulations occur on the high and low pressure sides, and are stronger than the global circulation. These local circulations contribute to the thermal mixing in each tower. The bottom distributor on the low pressure side can cause an uprising flow which leads to the local circulation. The design of the distributor is suggested to be elaborated based on these findings. (C) 2015 The Authors. Published by Elsevier Ltd.

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  • Cold testings of a windowed fluidized bed reactor using quartz sand for solar gasification of coke 査読

    N. Gokon, T. Tanabe, H. S. Cho, T. Hatamachi, T. Kodama

    ISES Solar World Congress 2015, Conference Proceedings   799 - 805   2015年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:International Solar Energy Society  

    A windowed fluidized bed reactor prototype was studied and developed for solar thermochemical gasification of coal cokes with steam and CO2. The windowed fluidized bed reactor is assumed to be combined with a newly developed beam-down optics. Recently, quartz sand was employed as a chemically-inert bed material for the fluidized bed and worked as a thermal transfer/storage medium inside the reactor for coke gasification under direct light irradiation. In order to design a laboratory-scale prototype windowed fluidized-bed containing of quartz sand and coke particles, the reactor model of fluidized bed was made from a transparent acrylic resin to allow us to observe a fluidizing particle through the sidewall of the reactor body
    a branching tube is equipped with the sidewall of the reactor to continuously supply coal-coke particles from a screw feeder. In the present study, in order to evaluate fluidization performance of coal-cokes, the pressure loss between the inlet and outlet gases was examined, and descending coal-coke particles on the sidewall of the reactor was observed in the reactor model. The moving velocity and distance of descending particles from the top to bottom of fluidized bed were measured by the visual observation of the tracer particles on outside wall of reactor model.

    DOI: 10.18086/swc.2015.04.24

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  • Redox and fluidization performances of Co3O4/CoO for solar Thermochemical energy storage 査読

    N. Gokon, S. Yokota, H. S. Cho, T. Hatamachi, T. Kodama

    ISES Solar World Congress 2015, Conference Proceedings   806 - 815   2015年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:International Solar Energy Society  

    Thermochemical energy storage using redox pair of Co3O4/CoO powders was studied for thermal energy storage (TES) using concentrated solar radiation as the energy source. Reversible chemical reactions (reduction - oxidation redox cycles) of oxides under air atmosphere are used to storage significant thermal energy via the enthalpies of the chemical reactions at high-temperature. A promising concept for solar TES is proposed using fluidized bed with Co3O4/CoO redox pair. In the present study, the effects of particles size of Co3O4/CoO powders on thermochemical storage performances are investigated in order to explore the potential of the material for fluidized-particle bed reactor. The Co3O4 powders with particle sizes of 100-200, 200-300, 300-500 and 500-700 μm were used to test redox performances by thermo-gravimetric analysis. A flowability (fluidization state) of Co3O4 powders in a fluidized bed reactor for thermochemical energy storage is also examined in this study. A basic relationship between pressure drop of inlet gas and gas flow rate was experimentally examined using bed materials with different particle sizes by a small-scale quartz reactor at ambient pressure and temperature.

    DOI: 10.18086/swc.2015.04.25

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  • Laboratory experiment and simulation of higherature fluidized bed air receiver for concentrated solar power generation 査読

    Koji Matsubara, Yuki Kazuma, Atsushi Sakurai, Tatsuya Kodama, Nobuyuki Gokon, Hyun-Seok Cho, Kazuo Yoshida, Yoshinori Nagase

    Nihon Enerugi Gakkaishi/Journal of the Japan Institute of Energy   94 ( 11 )   1323 - 1329   2015年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Japan Institute of Energy  

    This study proposes a t wo-tower t ype fluidized receiver for receiving concentrated s olar light at high temperatures is proposed. This fluidized receiver is coupled with the Miyazaki beam-down reflector system. The visualization and the numerical simulation was made for the laboratory model to show the fluid-dynamics and the heat transport as well as to elaborate the existing demonstration model. The experimental visualization of the cold model demonstrated that in each tower, the particles are moved by the aerated organized flow. The numerical simulation was made using the thermal input cited from the 5.0kWth sun simulator. The numerical simulation demonstrated that the inner particles are heated above 950 °C after 3.0 minutes of the aeration start time. The increase in temperature is caused by the intrusion of the heated particles from the high-pressure side tower to the low-pressure side tower. It is thus suggested that collective circulation occurs between high- and low-pressure side towers and this can be utilized for a direct thermal storage system.

    DOI: 10.3775/jie.94.1323

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  • Development of a receiver evaluation system using 30 kWth point concentration solar simulator 査読

    M. Nakakura, M. Ohtake, K. Matsubara, K. Yoshida, H. S. Cho, T. Kodama, N. Gokon

    INTERNATIONAL CONFERENCE ON CONCENTRATING SOLAR POWER AND CHEMICAL ENERGY SYSTEMS, SOLARPACES 2014   69   497 - 505   2015年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:ELSEVIER SCIENCE BV  

    The point-concentration receiver evaluation system was developed using the world class 30 kWth light source of 19 arc xenon lamps. The system comprises of a receiver unit, heat exchanger, blower, chiller and light source. Precise measurement of the thermal power absorbed by air was performed by the enthalpy rise of the coolant water and that of the exhausted air. The experimental test was performed using silicon carbide honeycomb in order to achieve a high air temperature of 560 degrees C. The efficiency of the receiver, based on the power of the aperture, was 40% to 80%. A three-dimensional simulation based on the dual cell approach was made to reveal detailed information of the flow and temperature fields. This successfully reproduced the thermal nonequilibrium between the solid and fluid parts of the receiver. The air exit temperature and efficiency of the numerical simulation were consistent with that determined experimentally. Air was suctioned from the broad space above the receiver top surface. The adopted simulation model with the free stream was confirmed to be essential for evaluating an open loop receiver. (C) 2015 Published by Elsevier Ltd.

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  • Cyclic properties of thermal storage/discharge for Al-Si alloy in vacuum for solar thermochemical fuel production 査読

    N. Gokon, S. Nakamura, T. Yamaguchi, T. Kodama

    INTERNATIONAL CONFERENCE ON CONCENTRATING SOLAR POWER AND CHEMICAL ENERGY SYSTEMS, SOLARPACES 2014   69   1759 - 1769   2015年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:ELSEVIER SCIENCE BV  

    Thermal energy storage using phase-change materials (PCM) can be utilized for load shaving or peak load shifting when coupled to a solar thermochemical reactor, reformer, or gasifier for the production of solar fuel. The PCM is embedded in packages or used in bulk in these storage systems, and therefore the compatibility of the encapsulation materials and the selection of the PCM are key factors for ensuring the long operational life of the system. Various kinds of molten fluoride, chloride and carbonate salts, and mixed molten salt, which function at high temperatures of over 500 degrees C, are known to cause corrosion or thermal degradation. It is therefore worth studying new high-temperature PCM thermal storage alternatives to these molten salts for use in solar thermochemical processes. In this study, the focus was on aluminum-silicon alloy (Al-Si alloy) as a high-temperature PCM thermal storage medium, and the compatibility of this alloy with graphite-carbon encapsulation material was experimentally examined. The cyclic properties of thermal storage/discharge for Al-Si alloy as a latent-heat energy storage material was studied with respect to various thermal cycles. A thermal stability test was performed for the Al-20wt% Si, Al-25wt% Si, Al-30wt% Si, and Al-35wt% Si alloys placed in the graphite container in vacuum. The temperature increasing and cooling performances of the Al-Si alloy were measured during the thermal storage (heat-charge) mode and during the cooling (heat-discharge) mode. The oxidation level of the Al-Si alloy after the cyclic reaction (20 cycles) was evaluated using an electron probe microanalyzer (EPMA). (C) 2015 The Authors. Published by Elsevier Ltd.

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  • Cyclic properties of thermal storage/discharge for Al-Si alloy in vacuum for solar thermochemical fuel production 査読

    N. Gokon, S. Nakamura, T. Yamaguchi, T. Kodama

    INTERNATIONAL CONFERENCE ON CONCENTRATING SOLAR POWER AND CHEMICAL ENERGY SYSTEMS, SOLARPACES 2014   69   1759 - 1769   2015年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:ELSEVIER SCIENCE BV  

    Thermal energy storage using phase-change materials (PCM) can be utilized for load shaving or peak load shifting when coupled to a solar thermochemical reactor, reformer, or gasifier for the production of solar fuel. The PCM is embedded in packages or used in bulk in these storage systems, and therefore the compatibility of the encapsulation materials and the selection of the PCM are key factors for ensuring the long operational life of the system. Various kinds of molten fluoride, chloride and carbonate salts, and mixed molten salt, which function at high temperatures of over 500 degrees C, are known to cause corrosion or thermal degradation. It is therefore worth studying new high-temperature PCM thermal storage alternatives to these molten salts for use in solar thermochemical processes. In this study, the focus was on aluminum-silicon alloy (Al-Si alloy) as a high-temperature PCM thermal storage medium, and the compatibility of this alloy with graphite-carbon encapsulation material was experimentally examined. The cyclic properties of thermal storage/discharge for Al-Si alloy as a latent-heat energy storage material was studied with respect to various thermal cycles. A thermal stability test was performed for the Al-20wt% Si, Al-25wt% Si, Al-30wt% Si, and Al-35wt% Si alloys placed in the graphite container in vacuum. The temperature increasing and cooling performances of the Al-Si alloy were measured during the thermal storage (heat-charge) mode and during the cooling (heat-discharge) mode. The oxidation level of the Al-Si alloy after the cyclic reaction (20 cycles) was evaluated using an electron probe microanalyzer (EPMA). (C) 2015 The Authors. Published by Elsevier Ltd.

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  • Flowability control of bed materials in a fluidized bed reactor for solar thermochemical process 査読

    T. Etori, N. Gokon, A. Takeuchi, T. Miki, M. Yokota, T. Kodama

    INTERNATIONAL CONFERENCE ON CONCENTRATING SOLAR POWER AND CHEMICAL ENERGY SYSTEMS, SOLARPACES 2014   69   1741 - 1749   2015年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:ELSEVIER SCIENCE BV  

    Hydrogen production by solar thermochemical process uses concentrated solar radiation as its energy source. Various thermochemical processes operating at technically manageable temperatures which are a solar thermochemical two-step water splitting and solar gasification of carbonaceous material have been extensively studied and demonstrated by researchers around the world. These processes are capable of converting high-temperature heat from concentrated solar radiation into clean hydrogen from water. In this study, in order to control a flowability (fluidization state) of bed materials in a fluidized bed reactor for thermochemical processes (two-step water splitting cycle and gasification of coal coke), firstly, a basic relationship between pressure drop of inlet gas and gas flow rate was experimentally examined using bed materials with different particle sizes by a small-scale quartz reactor at ambient pressure and temperature. Secondly, the CeO2 particles having the size determined by above-described flowability test were tested using a windowed fluidized bed reactor prototype. The fluidized bed of CeO2 particles was exposed to a concentrated Xe light by sun-simulator with an input power of about 5 kWth for the T-R step in order to release oxygen. The production rate and productivity of oxygen and the reactivity of CeO2 particles were examined in this paper. (C) 2015 The Authors. Published by Elsevier Ltd.

    DOI: 10.1016/j.egypro.2015.03.143

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  • Flowability control of bed materials in a fluidized bed reactor for solar thermochemical process 査読

    T. Etori, N. Gokon, A. Takeuchi, T. Miki, M. Yokota, T. Kodama

    INTERNATIONAL CONFERENCE ON CONCENTRATING SOLAR POWER AND CHEMICAL ENERGY SYSTEMS, SOLARPACES 2014   69   1741 - 1749   2015年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:ELSEVIER SCIENCE BV  

    Hydrogen production by solar thermochemical process uses concentrated solar radiation as its energy source. Various thermochemical processes operating at technically manageable temperatures which are a solar thermochemical two-step water splitting and solar gasification of carbonaceous material have been extensively studied and demonstrated by researchers around the world. These processes are capable of converting high-temperature heat from concentrated solar radiation into clean hydrogen from water. In this study, in order to control a flowability (fluidization state) of bed materials in a fluidized bed reactor for thermochemical processes (two-step water splitting cycle and gasification of coal coke), firstly, a basic relationship between pressure drop of inlet gas and gas flow rate was experimentally examined using bed materials with different particle sizes by a small-scale quartz reactor at ambient pressure and temperature. Secondly, the CeO2 particles having the size determined by above-described flowability test were tested using a windowed fluidized bed reactor prototype. The fluidized bed of CeO2 particles was exposed to a concentrated Xe light by sun-simulator with an input power of about 5 kWth for the T-R step in order to release oxygen. The production rate and productivity of oxygen and the reactivity of CeO2 particles were examined in this paper. (C) 2015 The Authors. Published by Elsevier Ltd.

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  • Internally-circulating fluidized bed reactor using thermal storage material for solar coal coke gasification 査読

    T. Abe, N. Gokon, T. Izawa, T. Kodama

    INTERNATIONAL CONFERENCE ON CONCENTRATING SOLAR POWER AND CHEMICAL ENERGY SYSTEMS, SOLARPACES 2014   69   1722 - 1730   2015年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:ELSEVIER SCIENCE BV  

    A windowed reactor prototype of internally-circulating fluidized bed is tested and demonstrated at laboratory scale for steam gasification of coal coke irradiated directly by concentrated Xe light from a 3-kWth sun simulator. The bed material is composed of particle mixture of coal coke and quartz sand. A coal coke of the bed material works as a carbonous feedstock, while quartz sand functions as a thermal storage/transfer medium inside the reactor. The fluidized bed reactor, having a transparent window due to incoming radiation of concentrated solar beam on the ceiling of the reactor, is designed to be combined with a solar reflective tower or beam-down optics. A potential of quartz sand in the internally-circulating fluidized bed reactor is evaluated for steam gasification of coal coke by gasification performance (CO, H-2 and CO2 production rates, carbon conversion, and lightto- chemical efficiency). The gasification performances for use of the particle mixture in the reactor are compared with that for use of coal coke particle. The fluidized bed of a particle mixture including coal coke and quartz sand was gasified at lower temperature with a higher rate in comparison to that of a coal coke. Furthermore, a use of smaller and lighter coal coke particles were easily converted to gaseous species due to larger surface area as well as the gasification rates. (C) 2015 The Authors. Published by Elsevier Ltd.

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  • Internally-circulating fluidized bed reactor using thermal storage material for solar coal coke gasification 査読

    T. Abe, N. Gokon, T. Izawa, T. Kodama

    INTERNATIONAL CONFERENCE ON CONCENTRATING SOLAR POWER AND CHEMICAL ENERGY SYSTEMS, SOLARPACES 2014   69   1722 - 1730   2015年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:ELSEVIER SCIENCE BV  

    A windowed reactor prototype of internally-circulating fluidized bed is tested and demonstrated at laboratory scale for steam gasification of coal coke irradiated directly by concentrated Xe light from a 3-kWth sun simulator. The bed material is composed of particle mixture of coal coke and quartz sand. A coal coke of the bed material works as a carbonous feedstock, while quartz sand functions as a thermal storage/transfer medium inside the reactor. The fluidized bed reactor, having a transparent window due to incoming radiation of concentrated solar beam on the ceiling of the reactor, is designed to be combined with a solar reflective tower or beam-down optics. A potential of quartz sand in the internally-circulating fluidized bed reactor is evaluated for steam gasification of coal coke by gasification performance (CO, H-2 and CO2 production rates, carbon conversion, and lightto- chemical efficiency). The gasification performances for use of the particle mixture in the reactor are compared with that for use of coal coke particle. The fluidized bed of a particle mixture including coal coke and quartz sand was gasified at lower temperature with a higher rate in comparison to that of a coal coke. Furthermore, a use of smaller and lighter coal coke particles were easily converted to gaseous species due to larger surface area as well as the gasification rates. (C) 2015 The Authors. Published by Elsevier Ltd.

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  • Simulation of flux distributions on the foam absorber with solar reactor for thermo-chemical two-step water splitting H-2 production cycle by the 45 kW(th) KIER solar furnace 査読

    H. S. Cho, N. Gokon, T. Kodama, Y. H. Kang, J. K. Kim

    INTERNATIONAL CONFERENCE ON CONCENTRATING SOLAR POWER AND CHEMICAL ENERGY SYSTEMS, SOLARPACES 2014   69   790 - 801   2015年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:ELSEVIER SCIENCE BV  

    The flux distributions on the device in the solar reactor with the solar furnace were studied. This study aims to understand of characters of concentrated sun rays through KIER solar furnace and design of device shape for uniform heat distribution on the device surface. For the calculation of heat flux on the device with the KIER solar furnace, the optical modeling program Soltrace was used. At first, the KIER 45 kW(th) solar furnace and flat disk type device shape was simulated for understand of past experimental results. And then 3 cylinder shape device model and 1 conical shape device model was suggested and the heat flux intensity on the device was calculated. Finally, 5 models which is including flat disk type device shape, 3 cylinder shape, and 1 conical shape device models was calculated and compared. The results show that the concentrated sun rays from dish and heat flux intensity are has a directional characteristic concentrated to normal direction than perpendicular direction. The results will be applied to next solar demonstrations which are design of new solar reactor and new device shape. (C) 2015 The Authors. Published by Elsevier Ltd.

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  • Simulation of flux distributions on the foam absorber with solar reactor for thermo-chemical two-step water splitting H-2 production cycle by the 45 kW(th) KIER solar furnace 査読

    H. S. Cho, N. Gokon, T. Kodama, Y. H. Kang, J. K. Kim

    INTERNATIONAL CONFERENCE ON CONCENTRATING SOLAR POWER AND CHEMICAL ENERGY SYSTEMS, SOLARPACES 2014   69   790 - 801   2015年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:ELSEVIER SCIENCE BV  

    The flux distributions on the device in the solar reactor with the solar furnace were studied. This study aims to understand of characters of concentrated sun rays through KIER solar furnace and design of device shape for uniform heat distribution on the device surface. For the calculation of heat flux on the device with the KIER solar furnace, the optical modeling program Soltrace was used. At first, the KIER 45 kW(th) solar furnace and flat disk type device shape was simulated for understand of past experimental results. And then 3 cylinder shape device model and 1 conical shape device model was suggested and the heat flux intensity on the device was calculated. Finally, 5 models which is including flat disk type device shape, 3 cylinder shape, and 1 conical shape device models was calculated and compared. The results show that the concentrated sun rays from dish and heat flux intensity are has a directional characteristic concentrated to normal direction than perpendicular direction. The results will be applied to next solar demonstrations which are design of new solar reactor and new device shape. (C) 2015 The Authors. Published by Elsevier Ltd.

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  • 4-2-3 45kW_<th>KIER太陽炉による水熱分解サイクル(2)円錐型CeO_2/MPSZ反応デバイスの太陽試験(Session 4-2 太陽熱・熱分解)

    土田 里志, CHO Hyun-Seok, 郷右近 展之, 児玉 竜也, KANG Yong-Heack

    日本エネルギー学会大会講演要旨集   24   176 - 177   2015年

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    記述言語:日本語   出版者・発行元:一般社団法人日本エネルギー学会  

    We have developed reactive foam devices in Niigata University for solar thermochemical two-step water-splitting to produce hydrogen from water. The hydrogen productivity of the reactive foam devices was cyclically examined as an international collaboration research by using 45kW_<th> dish type solar concentrator in Korea Institute of Energy Research at Korea. Different shape of foam devices and radiation method of solar furnace were tested for solar demonstration.

    DOI: 10.20550/jietaikaiyoushi.24.0_176

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  • 4-2-2 二段階水熱分解サイクルにおける金属酸化物の高活性化(Session 4-2 太陽熱・熱分解)

    須田 俊紀, 籏町 剛, 郷右近 展之, 児玉 竜也

    日本エネルギー学会大会講演要旨集   24   174 - 175   2015年

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    記述言語:日本語   出版者・発行元:一般社団法人日本エネルギー学会  

    Cerium oxide was examined as a redox material on cyclic reactivity for converting high-temperature heat into chemical fuels via solar two-step thermochemical water-splitting. In this study, in order to increase hydrogen and oxygen production in comparison to pure CeO_2, we synthesized a doping of 30mol% metal ion to the CeO_2 (30mol%M-CeO_<2-δ>), and tested the 30mol%M-CeO_<2-δ> powder for thermochemical two-step water-splitting to produce hydrogen and oxygen during cyclic reaction. The reactivity of the M-CeO_<2-δ> powder was evaluated for several cycles.

    DOI: 10.20550/jietaikaiyoushi.24.0_174

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  • Steam gasification of coal cokes in an internally circulating fluidized bed of thermal storage material for solar thermochemical processes 査読

    Nobuyuki Gokon, Takuya Izawa, Takehiko Abe, Tatsuya Kodama

    INTERNATIONAL JOURNAL OF HYDROGEN ENERGY   39 ( 21 )   11082 - 11093   2014年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    A laboratory-scale prototype windowed internally circulating fluidized-bed reactor made of quartz sand and coal coke particles was investigated for steam gasification using concentrated Xe-light radiation as the energy source. The quartz sand was used as a chemically inert bed material for the fluidized bed, while the coal coke particles functioned as the reacting particles for the endothermic gasification reaction. The advantages of using quartz sand as the bed material for the directly irradiated gasification reactor are as follows: (1) The bed height is maintained at a constant level during the gasification. (2) The quartz sand functions as a thermal transfer/storage medium inside the reactor. The gasification performances such as the production rates of CO, H-2, and CO2; carbon conversion; and light-to-chemical energy conversion were evaluated for the fluidized-bed reactor with a thermal transfer/storage medium (quartz sand). The effects of using the bed material (quartz sand) on the gasification performance are described in this paper. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

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  • Steam reforming of methane using double-walled reformer tubes containing high-temperature thermal storage Na2CO3/MgO composites for solar fuel production 査読

    Nobuyuki Gokon, Shohei Nakamura, Tsuyoshi Hatamachi, Tatsuya Kodama

    ENERGY   68   773 - 782   2014年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Double-walled reactor tubes containing thermal storage materials based on the molten carbonate salts-100 wt% Na2CO3 molten salt, 90 wt% Na2CO3/10 wt% MgO and 80 wt% Na2CO3/20 wt% MgO composite materials were studied for the performances of the reactor during the heat charging mode, while those of methane reforming with steam during heat discharging mode for solar steam reforming. The variations in the temperatures of the catalyst and storage material, methane conversion, duration of reforming for obtaining high levels of methane conversion (&gt; 90%), higher heating value (HHV) power of reformed gas and efficiency of the reactor tubes were evaluated for the double-walled reactor tubes and a single-wall reactor tube without the thermal storage. The results for the heat charging mode indicated that the composite thermal storage could successfully store the heat transferred from the exterior wall of the reactor in comparison to the pure molten-salt. The double-walled reactor tubes with the 90 wt% Na2CO3/10 wt% MgO composite material was the most desirable for steam reforming of methane to realize large HHV amounts of reformed gas and higher efficiencies during heat-discharging mode. (C) 2014 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.energy.2014.01.107

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  • Kinetics of thermal reduction step of thermochemical two-step water splitting using CeO2 particles: Master-plot method for analyzing non-isothermal experiments 査読

    T. Ishida, N. Gokon, T. Hatamachi, T. Kodama

    PROCEEDINGS OF THE SOLARPACES 2013 INTERNATIONAL CONFERENCE   49   1970 - 1979   2014年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:ELSEVIER SCIENCE BV  

    Thermochemical two-step water splitting cycle by concentrated solar heat has been studied as an energy conversion of solar energy into hydrogen energy. The thermochemical two-step water splitting cycle using metal oxide redox pair was composed of thermal reduction (T-R) step of metal oxide at higher temperature to release oxygen and, subsequent water decomposition (W-D) step of the reduced metal oxide with steam at lower temperature to produce hydrogen. Recently, cerium oxide (CeO2) is concerned as a redox pair of the thermochemical cycle for highly reactivity and cyclicity at high temperature. In this study, we focused a kinetic analysis of thermochemical two-step water splitting using cerium oxide. Various theoretical reaction models for thermal reduction (T-R) step of CeO2 particles are examined, and the appropriate reaction model for experimental results of thermogravimetric analysis was found by Master plot method. Finally, the reaction rate equation of thermal reduction is estimated. (C) 2013 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).

    DOI: 10.1016/j.egypro.2014.03.209

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  • Solar flux distribution of new beam-down solar concentrating system at Miyazaki for solar thermochemical processes 査読

    Shunta Tokunaga, Naoya Watanabe, Kei Omori, Tatsuya Kodama, Nobuyuki Gokon, Shoji Koikari, KazuoYoshida, Yoshinori Nagase, Katsushige Nakamura

    International Symposium on Fusion Tech 2013 at Korea, Seoul, Korea, January 15-17, 2014.   2014年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • Solar Hydrogen Production Via Thermochemical Two-Step Water Splitting Cycle Using CeO?/MPSZ Ceramic Foam device by KIER Solar Furnace 査読

    Takuya Myojin, Shintaro Kawakami, Hyun Seok Cho, Nobuyuki Gokon, Tatsuya Kodama, Yong Heack Kang, Sang Nam Lee, Khwan Kyo Chai, Hwan Ki Yoon, Hyun Jim Lee

    International Symposium on Fusion Tech 2013 at Korea, Seoul, Korea, January 15-17, 2014.   2014年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • Development of Solar Fluidized Bed Reactor For Hydrogen Production Via Thermochemical Two‐Step Water Splitting 査読

    Naoya Watanabe, Shunta Tokunaga, Kei Omori, Tsuyoshi Hatamachi, Nobuyuki Gokon, Tatsuya Kodama

    Grand Renewable Energy 2014 International Conference and Exhibition together with international solar energy society asia pacific conference 2014 and the 2nd asia wave and tidal energy conference, Tokyo Big Sight, Tokyo, Japan, July 27-August 1, 2014.   2014年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • Thermochemical Gasification of Coal Cokes Using Fluidized Bed Reactor for Solar−Hybrid Fuel Production 査読

    Nobuyuki Gokon, Takehiko Abe, Takuya Izawa, Chiaki Kogure, Tatsuya Kodama

    Grand Renewable Energy 2014 International Conference and Exhibition together with international solar energy society asia pacific conference 2014 and the 2nd asia wave and tidal energy conference, Tokyo Big Sight, Tokyo, Japan, July 27-August 1, 2014.   2014年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • CPC performances with a novel 100-kW beam-down solar concentrating system at Miyazaki for demonstration of thermochemical water-splitting reactors 査読

    Tatsuya Kodama, Nobuyuki Gokon, Koji Matsubara, Kazuo Yoshida, Souji Koikari, Hiroshi Kaneko, Katsusige Nakamura

    SolarPACES 2014, Beijing, China, September 16-19, 2014.   2014年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • DEVELOPMENT OF METAL-DOPED CERIA AIMED AT LOWER TEMPERATURE OF THERMAL REDUCTION STEP OF THERMOCHEMICAL TWO-STEP WATER-SPLITTING CYCLE FOR SOLAR HYDROGEN PRODUCTION 査読

    Toshinori Suda, Nobuyuki Gokon, Tatsuya Kodama

    AFORE 2014, Yeosu, Korea, November 17-20, 2014.   2014年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • FLUIDIZED BED REACTOR FOR SOLAR THERMOCHEMICAL TWO-STEP WATER-SPLITTING CYCLE 査読

    Akane Takeuchi, Tetsuro Etori, Shinosuke Yokota, Sumie Ito, Nobuyuki Gokon, Tatsuya Kodama

    AFORE 2014, Yeosu, Korea, November 17-20, 2014.   2014年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • SOLAR THERMOCHEMICAL TWO-STEP WATER-SPLITTING USING CEO2 COATED FOAM DEVICE FOR HYDROGEN PRODUCTION 査読

    Satoshi Tsuchida, Hyun Seok Cho, Shintaro Kawakami, Takuya Myojin, Nobuyuki Gokon, Tatsuya Kodama

    AFORE 2014, Yeosu, Korea, November 17-20, 2014.   2014年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • Thermochemical two-step water splitting cycle using Ni-ferrite and CeO2 coated ceramic foam devices by concentrated Xe-light radiation 査読

    S. Kawakami, T. Myojin, H. -S. Cho, T. Hatamachi, N. Gokon, T. Kodama

    PROCEEDINGS OF THE SOLARPACES 2013 INTERNATIONAL CONFERENCE   49   1980 - 1989   2014年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:ELSEVIER SCIENCE BV  

    Nickel ferrite (NiFe2O4) and pure cerium oxide (CeO2) supported on monoclinic zirconia (NiFe2O4/m-ZrO2) are proposed as promising redox materials for the production of hydrogen from water via a thermochemical two-step water splitting cycle. Ceramic foam devices coated with NiFe2O4/m-ZrO2 or pure CeO2 particles are prepared as a receiver/reactor operating a thermochemical water splitting cycle to produce hydrogen. The foam devices are examined in a directly irradiated receiver/reactor by a sun simulator on a laboratory scale. The purpose of this study is to examine the evolution of oxygen and hydrogen during the cyclization reaction different thermal-reduction (T-R) temperatures of 1450 and 1550 degrees C, and to compare the reproducible and stoichiometric oxygen/hydrogen production for both foam devices through a repeatable two-step reaction. In this study, a zirconia ceramic foam was used as a matrix for the reacting materials of NiFe2O4/m-ZrO2 or CeO2 particles. The zirconia ceramic foam has a diameter of 60 mm, a thickness of 15 mm, and a porosity of 10 cpi (cell number per linear inch). The loading amounts of reacting materials are 5 wt% for NiFe2O4/m-ZrO2 and 40 wt% for CeO2 particles. A concentrated Xe-beam is radiated to the foam device in a N-2 stream for the T-R step and in a N-2/steam gas mixture for the subsequent water-decomposition (W-D) step. (C) 2013 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).

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  • Thermochemical two-step water splitting cycle using Ni-ferrite and CeO2 coated ceramic foam devices by concentrated Xe-light radiation 査読

    S. Kawakami, T. Myojin, H. -S. Cho, T. Hatamachi, N. Gokon, T. Kodama

    PROCEEDINGS OF THE SOLARPACES 2013 INTERNATIONAL CONFERENCE   49   1980 - 1989   2014年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:ELSEVIER SCIENCE BV  

    Nickel ferrite (NiFe2O4) and pure cerium oxide (CeO2) supported on monoclinic zirconia (NiFe2O4/m-ZrO2) are proposed as promising redox materials for the production of hydrogen from water via a thermochemical two-step water splitting cycle. Ceramic foam devices coated with NiFe2O4/m-ZrO2 or pure CeO2 particles are prepared as a receiver/reactor operating a thermochemical water splitting cycle to produce hydrogen. The foam devices are examined in a directly irradiated receiver/reactor by a sun simulator on a laboratory scale. The purpose of this study is to examine the evolution of oxygen and hydrogen during the cyclization reaction different thermal-reduction (T-R) temperatures of 1450 and 1550 degrees C, and to compare the reproducible and stoichiometric oxygen/hydrogen production for both foam devices through a repeatable two-step reaction. In this study, a zirconia ceramic foam was used as a matrix for the reacting materials of NiFe2O4/m-ZrO2 or CeO2 particles. The zirconia ceramic foam has a diameter of 60 mm, a thickness of 15 mm, and a porosity of 10 cpi (cell number per linear inch). The loading amounts of reacting materials are 5 wt% for NiFe2O4/m-ZrO2 and 40 wt% for CeO2 particles. A concentrated Xe-beam is radiated to the foam device in a N-2 stream for the T-R step and in a N-2/steam gas mixture for the subsequent water-decomposition (W-D) step. (C) 2013 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).

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  • Flux measurement of a new beam-down solar concentrating system in Miyazaki for demonstration of thermochemical water splitting reactors 査読

    T. Kodama, N. Gokon, K. Matsubara, K. Yoshida, S. Koikari, Y. Nagase, K. Nakamura

    PROCEEDINGS OF THE SOLARPACES 2013 INTERNATIONAL CONFERENCE   49   1990 - 1998   2014年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:ELSEVIER SCIENCE BV  

    A two-step thermochemical water splitting cycle using nonstoichiometric cerium oxide is a promising solar thermochemical hydrogen production process. One of the present authors has developed new solar reactors using "internally circulating fluidized beds" with cerium oxide particles for the high-temperature cycle. These solar reactors need to be combined with a beam-down solar concentrating system. Niigata University, University of Miyazaki, and Mitaka Kohki Co. Ltd. recently started an R&D joint project to demonstrate the up-scaled fluidized bed reactors with solar. A new type of 100 kW(th) beam-down solar concentrating system was built in August, 2012 at the campus of University of Miyazaki. This paper describes the first results of solar flux measurements on the new Miyazaki beam-down system for demonstration of thermochemical water splitting reactors. The fluxes of concentrated solar radiation at the focus point were measured by moving an array of thirteen Gardon gauges. The solar power in an area of 130 x 130 cm in the focal spot was larger than 90 kWth during three hours of daytime radiation, exceeding 110 kW(th) around noon on October 12, 2012. A new CPC specific to this new beam-down system was designed and fabricated to concentrate the solar fluxes into a 44 cm diameter circle of the solar reactor aperture. The solar demonstration of the reactors will start at the Miyazaki beam-down system from October 2013. (C) 2013 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).

    DOI: 10.1016/j.egypro.2014.03.211

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  • Flux measurement of a new beam-down solar concentrating system in Miyazaki for demonstration of thermochemical water splitting reactors 査読

    T. Kodama, N. Gokon, K. Matsubara, K. Yoshida, S. Koikari, Y. Nagase, K. Nakamura

    PROCEEDINGS OF THE SOLARPACES 2013 INTERNATIONAL CONFERENCE   49   1990 - 1998   2014年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:ELSEVIER SCIENCE BV  

    A two-step thermochemical water splitting cycle using nonstoichiometric cerium oxide is a promising solar thermochemical hydrogen production process. One of the present authors has developed new solar reactors using "internally circulating fluidized beds" with cerium oxide particles for the high-temperature cycle. These solar reactors need to be combined with a beam-down solar concentrating system. Niigata University, University of Miyazaki, and Mitaka Kohki Co. Ltd. recently started an R&D joint project to demonstrate the up-scaled fluidized bed reactors with solar. A new type of 100 kW(th) beam-down solar concentrating system was built in August, 2012 at the campus of University of Miyazaki. This paper describes the first results of solar flux measurements on the new Miyazaki beam-down system for demonstration of thermochemical water splitting reactors. The fluxes of concentrated solar radiation at the focus point were measured by moving an array of thirteen Gardon gauges. The solar power in an area of 130 x 130 cm in the focal spot was larger than 90 kWth during three hours of daytime radiation, exceeding 110 kW(th) around noon on October 12, 2012. A new CPC specific to this new beam-down system was designed and fabricated to concentrate the solar fluxes into a 44 cm diameter circle of the solar reactor aperture. The solar demonstration of the reactors will start at the Miyazaki beam-down system from October 2013. (C) 2013 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).

    DOI: 10.1016/j.egypro.2014.03.211

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  • Solar demonstration of thermochemical two-step water splitting cycle using CeO2/MPSZ ceramic foam device by 45kW(th) KIER solar furnace 査読

    H. S. Cho, T. Myojin, S. Kawakami, N. Gokon, T. Kodama, Y. H. Kang, S. N. Lee, K. K. Chai, H. K. Yoon, H. J. Lee

    PROCEEDINGS OF THE SOLARPACES 2013 INTERNATIONAL CONFERENCE   49   1922 - 1931   2014年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:ELSEVIER SCIENCE BV  

    The joint international project of Niigata University (Japan) - Korea Institute of Energy Research, KIER (Korea) on the "Solar demonstration of Water-Splitting Reactor using Ceramic Foam Device" aims to develop a novel-type of solar reactor with reactive cerium oxide foam devices for high-temperature two-step thermochemical water splitting cycle, and to demonstrate its performances on sun with a 45-kW(th) solar furnace. The reactive CeO2 foam device for the two-step water splitting is proposed and prepared by Niigata University, Japan, and involves coating inert zirconia foam with reactive CeO2. The project includes the development of reactive foam devices, the new design and the fabrication of solar reactor with the reactive foam devices, and finally the solar demonstration on the KIER's 45-kW(th) solar furnace in Korea. In this paper, highly-active CeO2 particles were used as a redox material for preparing CeO2 foam devices. A ceramic foam disk made of MgO partially-stabilized Zirconia (MPSZ) was used as a ceramic matrix that was coated with the CeO2 particles. Solar thermochemical two-step water splitting was demonstrated with solar furnace in Korea system using the prepared CeO2-coated MPSZ (CeO2/MPSZ) foam devices. The prepared CeO2/MPSZ foam device has a diameter of 15 and 20cm and thickness of 2.5 cm, the loading of CeO2 was set to approximately 20 wt%.
    Then, the temperatures of the foam device at a center position were 1400-1600 degrees C for the T-R step, and 900-1100 degrees C for the subsequent W-D step. Hydrogen was successfully produced from the CeO2-MPSZ foam by a solar thermochemical two-step water-splitting, and the rate of hydrogen production and CeO2 conversion using 15 cm CeO2/MPSZ foam device were 215.6 mL/min and 3.67%, at 1st cycle. We also performed continuous testing for 20 cm diameter of the CeO2-MPSZ device, the rate of hydrogen production and CeO2 conversion were 443 ml/min and 3.27%, 1st cycle. (C) 2013 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).

    DOI: 10.1016/j.egypro.2014.03.204

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  • Solar demonstration of thermochemical two-step water splitting cycle using CeO2/MPSZ ceramic foam device by 45kW(th) KIER solar furnace 査読

    H. S. Cho, T. Myojin, S. Kawakami, N. Gokon, T. Kodama, Y. H. Kang, S. N. Lee, K. K. Chai, H. K. Yoon, H. J. Lee

    PROCEEDINGS OF THE SOLARPACES 2013 INTERNATIONAL CONFERENCE   49   1922 - 1931   2014年

     詳細を見る

    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:ELSEVIER SCIENCE BV  

    The joint international project of Niigata University (Japan) - Korea Institute of Energy Research, KIER (Korea) on the "Solar demonstration of Water-Splitting Reactor using Ceramic Foam Device" aims to develop a novel-type of solar reactor with reactive cerium oxide foam devices for high-temperature two-step thermochemical water splitting cycle, and to demonstrate its performances on sun with a 45-kW(th) solar furnace. The reactive CeO2 foam device for the two-step water splitting is proposed and prepared by Niigata University, Japan, and involves coating inert zirconia foam with reactive CeO2. The project includes the development of reactive foam devices, the new design and the fabrication of solar reactor with the reactive foam devices, and finally the solar demonstration on the KIER's 45-kW(th) solar furnace in Korea. In this paper, highly-active CeO2 particles were used as a redox material for preparing CeO2 foam devices. A ceramic foam disk made of MgO partially-stabilized Zirconia (MPSZ) was used as a ceramic matrix that was coated with the CeO2 particles. Solar thermochemical two-step water splitting was demonstrated with solar furnace in Korea system using the prepared CeO2-coated MPSZ (CeO2/MPSZ) foam devices. The prepared CeO2/MPSZ foam device has a diameter of 15 and 20cm and thickness of 2.5 cm, the loading of CeO2 was set to approximately 20 wt%.
    Then, the temperatures of the foam device at a center position were 1400-1600 degrees C for the T-R step, and 900-1100 degrees C for the subsequent W-D step. Hydrogen was successfully produced from the CeO2-MPSZ foam by a solar thermochemical two-step water-splitting, and the rate of hydrogen production and CeO2 conversion using 15 cm CeO2/MPSZ foam device were 215.6 mL/min and 3.67%, at 1st cycle. We also performed continuous testing for 20 cm diameter of the CeO2-MPSZ device, the rate of hydrogen production and CeO2 conversion were 443 ml/min and 3.27%, 1st cycle. (C) 2013 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).

    DOI: 10.1016/j.egypro.2014.03.204

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  • Solar demonstration of thermochemical two-step water splitting cycle using CeO2/MPSZ ceramic foam device by 45kW(th) KIER solar furnace 査読

    H. S. Cho, T. Myojin, S. Kawakami, N. Gokon, T. Kodama, Y. H. Kang, S. N. Lee, K. K. Chai, H. K. Yoon, H. J. Lee

    PROCEEDINGS OF THE SOLARPACES 2013 INTERNATIONAL CONFERENCE   49   1922 - 1931   2014年

     詳細を見る

    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:ELSEVIER SCIENCE BV  

    The joint international project of Niigata University (Japan) - Korea Institute of Energy Research, KIER (Korea) on the "Solar demonstration of Water-Splitting Reactor using Ceramic Foam Device" aims to develop a novel-type of solar reactor with reactive cerium oxide foam devices for high-temperature two-step thermochemical water splitting cycle, and to demonstrate its performances on sun with a 45-kW(th) solar furnace. The reactive CeO2 foam device for the two-step water splitting is proposed and prepared by Niigata University, Japan, and involves coating inert zirconia foam with reactive CeO2. The project includes the development of reactive foam devices, the new design and the fabrication of solar reactor with the reactive foam devices, and finally the solar demonstration on the KIER's 45-kW(th) solar furnace in Korea. In this paper, highly-active CeO2 particles were used as a redox material for preparing CeO2 foam devices. A ceramic foam disk made of MgO partially-stabilized Zirconia (MPSZ) was used as a ceramic matrix that was coated with the CeO2 particles. Solar thermochemical two-step water splitting was demonstrated with solar furnace in Korea system using the prepared CeO2-coated MPSZ (CeO2/MPSZ) foam devices. The prepared CeO2/MPSZ foam device has a diameter of 15 and 20cm and thickness of 2.5 cm, the loading of CeO2 was set to approximately 20 wt%.
    Then, the temperatures of the foam device at a center position were 1400-1600 degrees C for the T-R step, and 900-1100 degrees C for the subsequent W-D step. Hydrogen was successfully produced from the CeO2-MPSZ foam by a solar thermochemical two-step water-splitting, and the rate of hydrogen production and CeO2 conversion using 15 cm CeO2/MPSZ foam device were 215.6 mL/min and 3.67%, at 1st cycle. We also performed continuous testing for 20 cm diameter of the CeO2-MPSZ device, the rate of hydrogen production and CeO2 conversion were 443 ml/min and 3.27%, 1st cycle. (C) 2013 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).

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  • High-temperature fluidized receiver for concentrated solar radiation by a beam-down reflector system 査読

    K. Matsubara, Y. Kazuma, A. Sakurai, S. Suzuki, L. Soon-Jae, T. Kodama, N. Gokon, C. Hyun Seok, K. Yoshida

    PROCEEDINGS OF THE SOLARPACES 2013 INTERNATIONAL CONFERENCE   49   447 - 456   2014年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:ELSEVIER SCIENCE BV  

    This study proposes a novel fluidized receiver for absorbing concentrated solar light at high temperatures. Previously, a tubular receiver and a volumetric receiver were developed to make high-temperature air for a solar gas turbine system. The aim was to combine these elements with a tower reflector; however, it was challenging to install these heavy receivers on the top of the tower. Currently, a fluidized receiver prototype is tested by a 3 kWh solar simulator in preparation for a field test at the Miyazaki beam-down reflector system. The fluid dynamics of the prototype receiver is numerically investigated. The currently treated receiver is an inner-circulating fluidized bed spouted by concentric gas streams with high and low velocities in the center and outer annulus, respectively. The draft tube is submerged in the particles to organize particle circulation. Concentrated light irradiates the particles through a quartz window at the top of the receiver container. Such a fluidized bed was first adopted by Kodama et al. for thermochemical reactions; however, it is currently pursued for its potential as a high-temperature receiver aimed at concentrated solar power generation. Experiments of the prototype receiver (inner diameter = 45 mm) demonstrated that the inner particles are heated to a temperature greater than 900 degrees C and that an increase of the central gas velocity removes the excess temperature near the particle bed surface. A numerical computation suggests that the large-scale circulation of particles leads to the activation of thermal mixing. The currently proposed receiver is thus expected to attenuate re-radiation losses likely to occur in a conventional volumetric porous receiver. The scale-up of the receiver is being considered by the numerical computation for a field test in the Miyazaki 100 kWh beam-down reflector system. (C) 2013 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license

    DOI: 10.1016/j.egypro.2014.03.048

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  • High-temperature fluidized receiver for concentrated solar radiation by a beam-down reflector system 査読

    K. Matsubara, Y. Kazuma, A. Sakurai, S. Suzuki, L. Soon-Jae, T. Kodama, N. Gokon, C. Hyun Seok, K. Yoshida

    PROCEEDINGS OF THE SOLARPACES 2013 INTERNATIONAL CONFERENCE   49   447 - 456   2014年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:ELSEVIER SCIENCE BV  

    This study proposes a novel fluidized receiver for absorbing concentrated solar light at high temperatures. Previously, a tubular receiver and a volumetric receiver were developed to make high-temperature air for a solar gas turbine system. The aim was to combine these elements with a tower reflector; however, it was challenging to install these heavy receivers on the top of the tower. Currently, a fluidized receiver prototype is tested by a 3 kWh solar simulator in preparation for a field test at the Miyazaki beam-down reflector system. The fluid dynamics of the prototype receiver is numerically investigated. The currently treated receiver is an inner-circulating fluidized bed spouted by concentric gas streams with high and low velocities in the center and outer annulus, respectively. The draft tube is submerged in the particles to organize particle circulation. Concentrated light irradiates the particles through a quartz window at the top of the receiver container. Such a fluidized bed was first adopted by Kodama et al. for thermochemical reactions; however, it is currently pursued for its potential as a high-temperature receiver aimed at concentrated solar power generation. Experiments of the prototype receiver (inner diameter = 45 mm) demonstrated that the inner particles are heated to a temperature greater than 900 degrees C and that an increase of the central gas velocity removes the excess temperature near the particle bed surface. A numerical computation suggests that the large-scale circulation of particles leads to the activation of thermal mixing. The currently proposed receiver is thus expected to attenuate re-radiation losses likely to occur in a conventional volumetric porous receiver. The scale-up of the receiver is being considered by the numerical computation for a field test in the Miyazaki 100 kWh beam-down reflector system. (C) 2013 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license

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  • Carbonate molten-salt absorber/reformer: heating and steam reforming performance of reactor tubes 査読

    N. Gokon, S. Nakamura, K. Matsubara, T. Kodama

    PROCEEDINGS OF THE SOLARPACES 2013 INTERNATIONAL CONFERENCE   49   1940 - 1949   2014年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:ELSEVIER SCIENCE BV  

    Steam reforming of methane is a candidate process for converting concentrated high-temperature solar heat to chemical fuels because it is a high-temperature, highly endothermic process. We developed a tubular reformer system using novel double-walled reactor tubes with molten-salt thermal storage for solar reforming to produce hydrogen or synthetic gas (CO + H-2) from a gas mixture of methane and steam using concentrated solar radiation as an energy source. The high heat capacity and large latent heat (heat of solidification) of the molten salt circumvents rapid temperature changes in the reactor tubes at high temperatures under fluctuating insolation. In this paper, we focused on under intermittent heating-cooling mode, the steam reforming performance of double-walled reactor tubes with Na2CO3/MgO composite thermal storage in comparison to pure Na2CO3 thermal storage. A heating mode using an electric furnace simulates reactor startup in the morning and reheating of the reactor by concentrated solar radiation after brief periods of cloud passage. The intermittent heating-cooling mode simulates fluctuating incident solar radiation during cyclic short-term cloud passage. The temperature variations of the catalyst and storage material, methane conversion, and higher heating value power of the reformed gas were examined for the double-walled reactor tubes and a single-wall (C) 2013 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).

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  • Carbonate molten-salt absorber/reformer: heating and steam reforming performance of reactor tubes 査読

    N. Gokon, S. Nakamura, K. Matsubara, T. Kodama

    PROCEEDINGS OF THE SOLARPACES 2013 INTERNATIONAL CONFERENCE   49   1940 - 1949   2014年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:ELSEVIER SCIENCE BV  

    Steam reforming of methane is a candidate process for converting concentrated high-temperature solar heat to chemical fuels because it is a high-temperature, highly endothermic process. We developed a tubular reformer system using novel double-walled reactor tubes with molten-salt thermal storage for solar reforming to produce hydrogen or synthetic gas (CO + H-2) from a gas mixture of methane and steam using concentrated solar radiation as an energy source. The high heat capacity and large latent heat (heat of solidification) of the molten salt circumvents rapid temperature changes in the reactor tubes at high temperatures under fluctuating insolation. In this paper, we focused on under intermittent heating-cooling mode, the steam reforming performance of double-walled reactor tubes with Na2CO3/MgO composite thermal storage in comparison to pure Na2CO3 thermal storage. A heating mode using an electric furnace simulates reactor startup in the morning and reheating of the reactor by concentrated solar radiation after brief periods of cloud passage. The intermittent heating-cooling mode simulates fluctuating incident solar radiation during cyclic short-term cloud passage. The temperature variations of the catalyst and storage material, methane conversion, and higher heating value power of the reformed gas were examined for the double-walled reactor tubes and a single-wall (C) 2013 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).

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  • Kinetics of thermal reduction step of thermochemical two-step water splitting using CeO2 particles: Master-plot method for analyzing non-isothermal experiments 査読

    T. Ishida, N. Gokon, T. Hatamachi, T. Kodama

    PROCEEDINGS OF THE SOLARPACES 2013 INTERNATIONAL CONFERENCE   49   1970 - 1979   2014年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:ELSEVIER SCIENCE BV  

    Thermochemical two-step water splitting cycle by concentrated solar heat has been studied as an energy conversion of solar energy into hydrogen energy. The thermochemical two-step water splitting cycle using metal oxide redox pair was composed of thermal reduction (T-R) step of metal oxide at higher temperature to release oxygen and, subsequent water decomposition (W-D) step of the reduced metal oxide with steam at lower temperature to produce hydrogen. Recently, cerium oxide (CeO2) is concerned as a redox pair of the thermochemical cycle for highly reactivity and cyclicity at high temperature. In this study, we focused a kinetic analysis of thermochemical two-step water splitting using cerium oxide. Various theoretical reaction models for thermal reduction (T-R) step of CeO2 particles are examined, and the appropriate reaction model for experimental results of thermogravimetric analysis was found by Master plot method. Finally, the reaction rate equation of thermal reduction is estimated. (C) 2013 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).

    DOI: 10.1016/j.egypro.2014.03.209

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  • Comparative study of activity of cerium oxide at thermal reduction temperatures of 1300-1550 degrees C for solar thermochemical two-step water-splitting cycle 査読

    Nobuyuki Gokon, Sachi Sagawa, Tatsuya Kodama

    INTERNATIONAL JOURNAL OF HYDROGEN ENERGY   38 ( 34 )   14402 - 14414   2013年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Thermochemical two-step water-splitting using CeO2 (cerium oxide) particles was studied to examine oxygen and hydrogen productivity and repeatability at thermal reduction (T-R) temperatures of 1300-1550 degrees C and water decomposition (W-D) temperatures of 400-1000 degrees C for the production of hydrogen from water using concentrated solar radiation as the energy source. The temperature dependency of oxygen and hydrogen productivity and the cyclic repeatability of CeO2 are reported in this paper. The characteristic features of CeO2 particles in the thermochemical two-step water-splitting cycle are compared with the well-known highly active reactive mediums of zirconia-supported Ni-ferrites (NiFe2O4/m-ZrO2 and NiFe2O4/c-YSZ) and unsupported NiFe2O4. Copyright (C) 2013, Hydrogen En ergy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

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  • Oxygen-releasing step of nickel ferrite based on Rietveld analysis for thermochemical two-step water-splitting 査読

    Nobuyuki Gokon, Ken Kondo, Tsuyoshi Hatamachi, Mineo Sato, Tatsuya Kodama

    INTERNATIONAL JOURNAL OF HYDROGEN ENERGY   38 ( 12 )   4935 - 4944   2013年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    We investigated the thermal reduction (T-R) of NiFe2O4, either supported by m-ZrO2 or unsupported, as the oxygen-releasing step of a solar thermochemical water splitting cycle based on a ferrite/wustite redox system, by performing the Rietveld analysis using powder X-ray diffraction. The solid materials obtained after the T-R step at 1300-1400 degrees C were subjected to Rietveld analysis. The amounts and chemical compositions of the wustite phase produced by the T-R step and the remaining ferrite phase were identified quantitatively. Chemical reaction formulas for the different T-R temperatures were determined from the results. Consistency for the chemical reactions of the thermal reduction was discussed and evaluated comparing the O2 amounts predicted by the chemical reaction formulas and measured experimentally by mass spectrometry. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

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  • 4-4-2 二段階水熱分解サイクルにおけるセリウム酸化物の高活性化に関する研究(4-4 太陽熱・水素製造,Session 4 新エネルギー)

    佐川 幸, 小野 顕広, 籏町 剛, 郷右近 展之, 児玉 竜也

    日本エネルギー学会大会講演要旨集   22   178 - 179   2013年

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    記述言語:日本語   出版者・発行元:一般社団法人日本エネルギー学会  

    Cerium oxide was examined as a redox material on cyclic reactivity for converting high-temperature heat into chemical fuels via solar two-step thermochemical water-splitting. In this study, the thermal reduction of metal-doped cerium particles was examined at 1500℃, and the subsequent water-decomposition step was performed at 800-1150℃. The oxygen and hydrogen productivity were measured at each step, and the stoichiometry was evaluated.

    DOI: 10.20550/jietaikaiyoushi.22.0_178

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  • 4-4-3 二段階水熱分解サイクルにおけるCeO_2の熱還元反応の速度解析(4-4 太陽熱・水素製造,Session 4 新エネルギー)

    佐藤 祐輔, 石田 知也, 籏町 剛, 郷右近 展之, 児玉 竜也

    日本エネルギー学会大会講演要旨集   22   180 - 181   2013年

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    記述言語:日本語   出版者・発行元:一般社団法人日本エネルギー学会  

    Cerium oxide was examined as a redox material on cyclic reactivity for converting high-temperature heat into chemical fuels via solar two-step thermochemical water-splitting. The thermal reduction of the cerium particles was conducted at 1000-1500℃, and oxygen production rate were measured. The kinetics of oxygen production for thermal reduction step was analyzed, then Arrhenius parameter and reaction model equation were evaluated.

    DOI: 10.20550/jietaikaiyoushi.22.0_180

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  • 4-4-5 45kW_<th>KIER太陽炉によるCeO_2/MPSZ反応デバイスを用いた水分解サイクルの太陽試験(4-4 太陽熱・水素製造,Session 4 新エネルギー)

    CHO Hyun Seok, 川上 慎太郎, 明神 卓弥, 籏町 剛, 郷右近 展之, 児玉 竜也, KANG Yong Heack

    日本エネルギー学会大会講演要旨集   22   184 - 185   2013年

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    記述言語:日本語   出版者・発行元:一般社団法人日本エネルギー学会  

    Joint international project of Niigata University (Japan) -Korean Institute of Energy Research, KIER (Kora) on the "Solar demonstration of Water-Splitting Reactor using Ceramic Foam Device" aims to develop a novel-type of solar reactor with reactive cerium- or iron oxides-coated foam devices for high-temperature two-step thermochemical water splitting cycle, and to demonstrate its performances on sun with a 40-kW_<th> solar furnace. The reactive CeO_2 foam device for the two-step water splitting is proposed and prepared by Niigata University, Japan, and involves coating an inert zirconia foam with reactive CeO_2 or ferrite-zirconia redox materials. The project includes the development of reactive foam devices, the new design and the fabrication of solar reactor with the reactive foam devices, and finally the solar demonstration on the KIER's 45-kW_<th> solar furnace in Korea. In this paper, highly-active CeO_2 particles were used as a redox material for preparing CeO_2 foam devices. A ceramic foam disk made of MgO partially-stabilized Zirconia (MPSZ) was used as a ceramic matrix that was coated with the CeO_2 particles. Solar thermochemical two-step water splitting was demonstrated using the prepared CeO_2-coated MPSZ (CeO_2/MPSZ) foam devices in Korea.

    DOI: 10.20550/jietaikaiyoushi.22.0_184

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  • 4-4-4 内循環流動層ソーラー反応器によるCeO_2の二段階水熱分解反応(4-4 太陽熱・水素製造,Session 4 新エネルギー)

    大森 圭, 徳永 駿太, 渡部 尚哉, 籏町 剛, 郷右近 展之, 児玉 竜也

    日本エネルギー学会大会講演要旨集   22   182 - 183   2013年

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    記述言語:日本語   出版者・発行元:一般社団法人日本エネルギー学会  

    Thermochemical two-step water-splitting cycle, which utilizes concentrated solar radiation as a energy source and uses steam as a chemical source, is a one of the most promising hydrogen productions from water, We are developing 2 types of windowed solar chemical reactors with internally-circulating fluidized bed of cerium oxide particles for hydrogen production via thermochemical two-step water-splitting. In the present work, the performance of each solar reactor with the internally circulating fluidized beds was examined for two-step water splitting of thermal reduction and water-decomposition using their particles under 5kW_<th> sun-simulator.

    DOI: 10.20550/jietaikaiyoushi.22.0_182

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  • CO2 gasification of coal cokes using internally circulating fluidized bed reactor by concentrated Xe-light irradiation for solar gasification 査読

    Nobuyuki Gokon, Ryuta Ono, Tsuyoshi Hatamachi, Li Liuyun, Hee-Joon Kim, Tatsuya Kodama

    INTERNATIONAL JOURNAL OF HYDROGEN ENERGY   37 ( 17 )   12128 - 12137   2012年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    For the solar thermochemical gasification of coal coke to produce CO + H-2 synthetic gas using concentrated solar radiation, a windowed reactor prototype is tested and demonstrated at laboratory scale for CO2 gasification of coal coke using concentrated Xe light from a 3-kW(th) sun simulator. The reactor was designed to be combined with a solar reflective tower or beam-down optics. The results for gasification performance (CO production rate, carbon conversion, and light-to-chemical efficiency) are shown for various CO2 flow rates and ratios. A kinetics analysis based on homogeneous and shrinking core models and the temperature distributions of the prototype particle bed are compared with those for a conventional fluidized bed reactor tested under the same Xe light irradiation and CO2 flow-rate conditions. The effectiveness and potential impacts of internally circulating fluidized bed reactors for enhancing gasification performance levels and inducing consistently higher bed temperatures are discussed in this paper. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

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  • Heat Transfer characteristics of internally circulating fluidized bed solar reactor 査読

    Atsushi Sakurai, So Sakuma, Gokon Nobuyuki, Koji Matsubara, Kodama Tatsuya

    SolarPACES 2012, Marrakech, Morocco, September 11-14, 2012.   2012年

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  • Steam gasification of coal cokes using fluidized bed reactor for solar thermochemical conversion 査読

    Nobuyuki Gokon, Ryuta Ono, Kei Omori, Tsuyoshi Hatamachi, Li Liuyun, Hee Joon Kim, Tatsuya Kodama

    SolarPACES 2012, Marrakech, Morocco, September 11-14, 2012.   2012年

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  • Two-step switching test of water-splitting process using internally-circulating fluidized bed reactor 査読

    Kei Omori, Nobuyuki Gokon, Tsuyoshi Hatamachi, Tatsuya Kodama

    SolarPACES 2012, Marrakech, Morocco, September 11-14, 2012.   2012年

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  • Solar Demonstration Project on a Novel Fluidized Bed Reactor for “Single-processed” Thermochemical Water-splitting Cycle with a Beam-Down Concentrating System at Miyazaki 査読

    Tatsuya Kodama, Nobuyuki Gokon, Kei Omori, Yoshinori Nagase, Katsushige Nakamura

    SolarPACES 2012, Marrakech, Morocco, September 11-14, 2012.   2012年

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  • COMPARISON STUDIES OF REACTIVITY ON NICKEL-FERRITE AND CERIUM-OXIDE REDOX MATERIALS FOR TWO-STEP THERMOCHEMICAL WATER SPLITTING BELOW 1400 degrees C 査読

    Tatsuya Kodama, Nobuki Imaizumi, Nobuyuki Gokon, Tsuyoshi Hatamachi, Daiki Aoyagi, Ken Kondo

    PROCEEDINGS OF THE ASME 5TH INTERNATIONAL CONFERENCE ON ENERGY SUSTAINABILITY 2011, PTS A-C   1617 - 1623   2012年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:AMER SOC MECHANICAL ENGINEERS  

    A two-step thermochemical water splitting cycle using a redox system of non-volatile metal oxide is one of the promising processes for converting concentrated solar high-temperature heat into clean hydrogen in sun-belt regions. In the 1st step of the cycle or the thermal reduction step, metal oxide is thermally reduced to release oxygen molecules in an inert gas atmosphere at a higher temperature above 1400 degrees C. In the second step or the water-decomposition step at a lower temperature, the thermally-reduced metal oxide reacts with steam to produce hydrogen. As the reactive redox metal oxide materials to be capable of working below 1400 degrees C, nickel-doped iron oxides or Ni-ferrites supported on zirconia, and non-stoichiometric cerium oxides are the promising working materials. In the present work, a series of the nickel-ferrite redox materials of monoclinic-zirconia-supported, cubicYSZ(yttrium-stabilized zirconia)-supported, and non-supported Ni-ferries and non-stoichiometric cerium oxide were compared on reactivity for two-step thermochemical water splitting cycle. The monoclinic-zirconia-supported Ni-ferrite produced the most quantity of hydrogen in the repeated cycles when the thermal reduction step was performed for 30 mm at 1400 degrees C and the water decomposition step for 60 min at 1000 degrees C.

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  • The basic study about reforming biomass-tar using catalysts for solar energy biomass gasfication 査読

    Liuyun Li, Gokon Nobuyuki, Kodama Tatsuya, Tadaaki Shimizu, Hee Joon Kim

    SolarPACES 2012, Marrakech, Morocco, September 11-14, 2012.   2012年

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  • 4-4-3 発泡体反応デバイスによる水熱分解サイクル試験(4-4 太陽熱発電・水素製造2,Session 4 新エネルギー)

    佐藤 直樹, 川上 慎太郎, 明神 卓弥, 籏町 剛, 郷右近 展之, 児玉 竜也, SEO Taebeom

    日本エネルギー学会大会講演要旨集   21   226 - 227   2012年

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    記述言語:日本語   出版者・発行元:一般社団法人日本エネルギー学会  

    We have developed reactive foam devices for solar thermochemical two-step water-splitting to produce hydrogen from water. We have researched the hydrogen production activity of the reactive foam devices by 3kW sun-simulator in Niigata University and by 5kW dish type solar concentrator in Inha University in Korea. Solar hydrogen productions were cyclically demonstrated for nine cycles at solar irradiation test at Korea.

    DOI: 10.20550/jietaikaiyoushi.21.0_226

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  • 4-5-1 ソーラー改質用Ni/MgO-Al_2O_3触媒デバイスの開発(4-5 太陽熱発電・水素製造3,Session 4 新エネルギー)

    嶋脇 一賢, 中村 彰兵, 籏町 剛, 郷右近 展之, 児玉 竜也

    日本エネルギー学会大会講演要旨集   21   230 - 231   2012年

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    記述言語:日本語   出版者・発行元:一般社団法人日本エネルギー学会  

    Catalytically-activated ceramic foam device has been developed as a solar receiver/absorber for use in methane reforming under concentrated solar radiation as an energy source. Ni/MgO-Al_2O_3 catalysts were loaded on the SiC ceramic foam. Catalytic activity and kinetics for methane reforming were studied using Ni/MgO-Al_2O_3/SiC foam device under Xe-light irradiation and electric furnace, respectively.

    DOI: 10.20550/jietaikaiyoushi.21.0_230

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  • 4-5-2 Na_2CO_3/MgO溶融塩ソーラーレシーバー反応管に関する研究(4-5 太陽熱発電・水素製造3,Session 4 新エネルギー)

    高橋 将吾, 栗田 慎二, 籏町 剛, 櫻井 篤, 郷右近 展之, 児玉 竜也

    日本エネルギー学会大会講演要旨集   21   232 - 233   2012年

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    記述言語:日本語   出版者・発行元:一般社団法人日本エネルギー学会  

    Double-walled reactor tubes with molten-salt thermal storage were developed for solar air receiver to generate electricity and for solar reforming to produce solar fuel. A mixture of Na_2CO_3 and MgO was loaded as a thermal storage medium into the outer annulus of that. Performances of the reactor tubes were studied as an air receiver and as a reformer tube in the present study.

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  • A Study of Themal Design for the Development of High-efficiency Fluidized Bed Solar Reactor

    So Sakuma, Atsushi Sakurai, Kyohei Ogino, Seung-Jae Lee, Koji Matsubara, Nobuyuki Gokon, Tatsuya Kodama

    Proceedings of the 8th international conference on flow dynamics   562 - 563   2011年11月

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  • Numerical Visualization of Radiative Heat Flux of Dispersed Particles Irradiated by Solar Light

    S. Sakuma, A. Sakurai, K. Matsubara, N. Gokon, T. Kodama

    Proceedings of the 11th Asian Symposium on Visualization (ASV11)   ASV11-po-33   2011年6月

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  • Thermochemical two-step water splitting by internally circulating fluidized bed of NiFe2O4 particles: Successive reaction of thermal-reduction and water-decomposition steps 査読

    Nobuyuki Gokon, Tetsuro Mataga, Nobuyuki Kondo, Tatsuya Kodama

    INTERNATIONAL JOURNAL OF HYDROGEN ENERGY   36 ( 8 )   4757 - 4767   2011年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Thermochemical two-step water splitting using a redox system of iron-based oxides or ferrites is a promising process for producing hydrogen without CO2 emission by the use of high-temperature solar heat as an energy source and water as a chemical source. In this study, thermochemical hydrogen production by two-step water splitting was demonstrated on a laboratory scale by using a single reactor of an internally circulating fluidized bed. This involved the successive reactions of thermal-reduction (T-R) and water-decomposition (W-D). The internally circulating fluidized bed was exposed to simulated solar light from Xe lamps with an input power of 2.4-2.6 kW(th) for the T-R step and 1.6-1.7 kW(th) for the subsequent W-D step. The feed gas was switched from an inert gas (N-2) in the T-R step to a gas mixture of N-2 and steam in the W-D step. NiFe2O4/m-ZrO2 and unsupported NiFe2O4 particles were tested as a fluidized bed of reacting particles, and the production rate and productivity of hydrogen and the reactivity of reacting particles were examined. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

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  • Ferrite/zirconia-coated foam device prepared by spin coating for solar demonstration of thermochemical water-splitting 査読

    Nobuyuki Gokon, Tatsuya Kodama, Nobuki Imaizumi, Jun Umeda, Taebeom Seo

    INTERNATIONAL JOURNAL OF HYDROGEN ENERGY   36 ( 3 )   2014 - 2028   2011年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    A Ferrite/zirconia foam device in which reticulated ceramic foam was coated with zirconia-supported Fe(3)O(4) or NiFe(2)O(4) as a reactive material was prepared by a spin-coating method. The spin-coating method can shorten the preparation period and reduce the coating process as compared to the previous wash-coating method. The foam devices were examined for hydrogen productivity and cyclic reactivity in thermochemical two-step water-splitting. The reactivity of these foam devices were studied for the thermal reduction of ferrite on a laboratory scale using a sun simulator to simulate concentrated solar radiation, while the thermally reduced foam devices were reacted with steam in another quartz reactor under homogeneous heating in an infrared furnace. The most reactive foam device, NiFe(2)O(4)/m-ZrO(2)/MPSZ, was tested for successive two-step water-splitting in a windowed single reactor using solar-simulated Xe-beam irradiation with a power input of 0.4-0.7 kW(th). The production of hydrogen continued successfully in the 20 cycles that were demonstrated using the NiFe(2)O(4)/m-ZrO(2)/MPSZ foam device. The NiFe(2)O(4)/m-ZrO(2)/MPSZ foam device produced hydrogen at a rate of 1.1-4.6 cm(3) per gram of device through 20 cycles and reached a maximum ferrite conversion of 60%. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.

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  • Kinetics of methane reforming over Ru/gamma-Al2O3-catalyzed metallic foam at 650-900 degrees C for solar receiver-absorbers 査読

    Nobuyuki Gokon, Yuhei Yamawaki, Daisuke Nakazawa, Tatsuya Kodama

    INTERNATIONAL JOURNAL OF HYDROGEN ENERGY   36 ( 1 )   203 - 215   2011年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The kinetics of methane reforming over Ru/gamma-Al2O3-catalyzed high porosity Ni-Cr-Al foam were examined at temperatures of 650-900 degrees C in a quartz tubular reactor using an electric furnace. The kinetic data were analyzed by four different types of kinetic models based on the basic, Eley-Rideal, Langmuir-Hinshelwood, and stepwise mechanisms. Validation of the kinetic models was carried out by calculating the determination coefficient r(2) between the predicted and the experimental results for each model. The absolute average deviation percentage (AAD%) between the predicted and the experimental results was also estimated for each model. The kinetic model based on the reversible stepwise mechanism provided the best prediction of the experimental reforming rates with an AAD value of 6% in the range 650-850 degrees C. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.ijhydene.2010.09.042

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  • Water-Splitting Foam Device Reactor for Solar Thermochemical Hydrogen Production 査読

    Naoki Sato, Nobuki Imaizumi, Masanori Sugisaki, Tsuyoshi Hatamachi, Seo Taebeom, Nobuyuki Gokon, Tatsuya Kodama

    International Symposium on Fusion Tech 2011 at Dalian, Dalian, China, December 15-17, 2011.   2011年

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  • HIGH-TEMPERATURE SOLAR THERMOCHEMICAL HYDROGEN PRODUCTION 査読

    Tatsuya Kodama, Tetsuro Mataga, Kei Oomori, Tsuyoshi Hatamachi, Nobuyuki Gokon

    International Symposium on Fusion Tech 2011 at Dalian, Dalian, China, December 15-17, 2011.   2011年

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  • 3kWth Internally circulating fluidized bed reactor for solar gasification of coal cokes 査読

    Nobuyuki Gokon, Ryuta Ono, Tsuyoshi Hatamachi, Li Liuyun, Hee Joon Kim, Atsushi Sakurai, Koji Matsubara, Tatsuya Kodama

    SolarPACES 2011, Granada, Spain, 20-23 September, 2011.   2011年

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  • Continuous hydrogen production by an internally-curcurating fluidized particle bed reactor for thermochemical water splitting 査読

    Tatsuya Kodama, Tetsuro Mataga, Nobuki Imaizumi, Tsuyoshi Hatamachi, Nobuyuki Gokon

    SolarPACES 2011, Granada, Spain, 20-23 September, 2011.   2011年

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  • Activity test of a ferrite foam device reactor for solar thermochemical two-step water-splitting 査読

    Nobuki Imaizumi, Naoki Sato, Tsuyoshi Hatamachi, Taebeom Seo, Nobuyuki Gokon, Tatsuya Kodama

    SolarPACES 2011, Granada, Spain, 20-23 September, 2011.   2011年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • FUNDAMENTAL STUDY OF RADIATIVE TRANSFER ANALYSIS OF INTERNALLY CIRCULATING FLUIDIZED BED SOLAR REACTOR 査読

    Atsushi Sakurai, So Sakuma, Nobuyuki Gokon, Koji Matsubara, Tatsuya Kodama

    SolarPACES 2011, Granada, Spain, 20-23 September, 2011.   2011年

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  • Solar Thermochemical Two Step Water-Splitting by Beam Down Solar Concentrating System 査読

    Kei Omori, Tetsuro Mataga, Megumi Saito, Tsuyoshi Hatamachi, Nobuyuki Gokon, Tatsuya Kodama

    International Symposium on Fusion Tech 2011 at Dalian, Dalian, China, December 15-17, 2011.   2011年

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  • 4-2-2 セリウム酸化物による二段階水熱分解サイクル(4-2 太陽熱発電・水素製造2,Session4 新エネルギー,研究発表)

    青柳 大樹, 掛布 綾香, 今泉 伸樹, 籏町 剛, 郷右近 展之, 児玉 竜也

    日本エネルギー学会大会講演要旨集   20   216 - 217   2011年

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    記述言語:日本語   出版者・発行元:一般社団法人日本エネルギー学会  

    Cerium oxide was examined as a redox material on cyclic reactivity for converting high-temperature heat into chemical fuels via solar two-step thermochemical water-splitting. The thermal reduction of the cerium particles was conducted at 1300-1550℃, and the subsequent water-decomposition step was performed at 1000℃. The oxygen and hydrogen productivity were measured at each step, and the stoichiometry was evaluated.

    DOI: 10.20550/jietaikaiyoushi.20.0_216

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  • 4-2-3 内循環流動層反応器による二段階水熱分解反応の一段階システム化に関する研究(4-2 太陽熱発電・水素製造2,Session4 新エネルギー,研究発表)

    又賀 哲郎, 伊藤 博人, 星野 愛実, 今泉 伸樹, 籏町 剛, 郷右近 展之, 児玉 竜也

    日本エネルギー学会大会講演要旨集   20   218 - 219   2011年

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    記述言語:日本語   出版者・発行元:一般社団法人日本エネルギー学会  

    A windowed solar chemical reactor with an internally-circulating fluidized bed of metal oxides particles has been developed for realizing hydrogen production from water via the thermochemical two-step water-splitting cycle. In this research, the authors tried to systemize the two-step water-splitting processes into single-step in an internally-circulating fluidized bed reactor. The single-step systemized reactor using the internally-circulating fluidized bed of reacting particles was tested by solar-simulated Xe light irradiation and evaluated on hydrogen productivity.

    DOI: 10.20550/jietaikaiyoushi.20.0_218

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  • 4-2-1 リートベルト解析による二段階水熱分解セラミックの反応性向上に関する研究(4-2 太陽熱発電・水素製造2,Session4 新エネルギー,研究発表)

    近藤 建, 田中 良樹, 佐藤 祐輔, 籏町 剛, 郷右近 展之, 児玉 竜也

    日本エネルギー学会大会講演要旨集   20   214 - 215   2011年

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    記述言語:日本語   出版者・発行元:一般社団法人日本エネルギー学会  

    Reactive ceramics of m-ZrO_2-supported NiFe_2O_4 and unsupported NiFe_2O_4 were analyzed by Rietveld method for enhancing hydrogen productivity for solar thermochemical two-step water-splitting. In this paper, the reduced phase (wustite phase) and the remaining ferrite phase obtained after that their reactive ceramics were thermally reduced at 1300-1400℃ was examined, and the composition and the existence ratio of them were determined. The relation between the reduction temperature and the reaction activity was discussed.

    DOI: 10.20550/jietaikaiyoushi.20.0_214

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  • 球面調和関数法による分散粒子群の2次元軸対称ふく射輸送シミュレーション

    櫻井 篤, 佐久間 壮, 松原 幸治, 郷右近 展之, 児玉 竜也

    日本伝熱シンポジウム講演論文集   2011   343 - 343   2011年

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    記述言語:日本語   出版者・発行元:社団法人 日本伝熱学会  

    次世代のCO2フリー水素製造法として高温太陽集熱による二段階水熱分解サイクルが注目されている.近年,反応性セラミック(金属酸化物)粒子による内循環流動層式ソーラー熱分解器が児玉らによって開発され,水素製造の実証実験が行われている.本研究の目的は,反応器内の分散粒子群による太陽光の吸収・散乱を高速かつ正確に予測できるふく射輸送モデルを開発することである.本研究では,多重散乱を伴うふく射輸送問題に適した解析モデルとして,球面調和関数法を採用し,数値解析コードの開発を行う.

    DOI: 10.11368/nhts.2011.0.343.0

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  • Coal Coke Gasification in a Windowed Solar Chemical Reactor for Beam-Down Optics 査読

    Tatsuya Kodama, Nobuyuki Gokon, Shu-ich Enomoto, Shouta Itoh, Tsuyoshi Hatamachi

    JOURNAL OF SOLAR ENERGY ENGINEERING-TRANSACTIONS OF THE ASME   132 ( 4 )   041004-6 - 041004-6   2010年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ASME-AMER SOC MECHANICAL ENG  

    Solar thermochemical processes, such as solar gasification of coal, require the development of a high temperature solar reactor operating at temperatures above 1000 degrees C. Direct solar energy absorption by reacting coal particles provides efficient heat transfer directly to the reaction site. In this work, a windowed reactor prototype designed for the beam-down optics was constructed at a laboratory scale and demonstrated for CO(2) gasification of coal coke using concentrated visible light from a sun-simulator as the source of energy. Peak conversion of light energy to chemical fuel ( CO) of 14% was obtained by irradiating a fluidized bed of 500-710 mu m coal coke size fraction with a power input of about 1 kW and a CO(2) flow-rate of 6.5 dm(3) min(-1) at normal conditions. [DOI: 10.1115/1.4002081]

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  • Comparative study of the activity of nickel ferrites for solar hydrogen production by two-step thermochemical cycles 査読

    Fernando Fresno, Tomoaki Yoshida, Nobuyuki Gokon, Rocio Fernandez-Saavedra, Tatsuya Kodama

    INTERNATIONAL JOURNAL OF HYDROGEN ENERGY   35 ( 16 )   8503 - 8510   2010年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    In this work, we compare the activity of unsupported and monoclinic zirconia supported nickel ferrites, calcined at two different temperatures, for solar hydrogen production by two-step water-splitting thermochemical cycles at low thermal reduction temperature. Commercial nickel ferrite, both as-received and calcined in the laboratory, as well as laboratory made supported NiFe(2)O(4), are employed for this purpose. The samples leading to higher hydrogen yields, averaged over three cycles, are those calcined at 700 degrees C in each group (supported and unsupported) of materials. The comparison of the two groups shows that higher chemical yields are obtained with the supported ferrites due to better utilisation of the active material. Therefore, the highest activity is obtained with ZrO(2)-supported NiFe(2)O(4) calcined at 700 degrees C. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.ijhydene.2010.05.032

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  • Ni/MgO-Al2O3 and Ni-Mg-O catalyzed SiC foam absorbers for high temperature solar reforming of methane 査読

    Nobuyuki Gokon, Yuhei Yamawaki, Daisuke Nakazawa, Tatsuya Kodama

    INTERNATIONAL JOURNAL OF HYDROGEN ENERGY   35 ( 14 )   7441 - 7453   2010年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Ni catalyst supported on MgO-Al2O3 (Ni/MgO-Al2O3) prepared from hydrotalcite, and Ni-Mg-O catalyst are studied in regard to their activity in the CO2 reforming of methane at high temperatures in order to develop a catalytically activated foam receiver absorber for use in solar reforming. First, the activity of their powder catalysts is examined. Ni/MgO-Al2O3 powder catalyst exhibits a remarkable degree of high activity and thermal stability as compared with Ni-Mg-O powder catalyst. Secondly, a new type of catalytically activated ceramic foam absorber - Ni/MgO-Al2O3/SiC - and Ni-Mg-O catalyzed SiC foam absorber are prepared and their activity is evaluated using a laboratory-scale receiver reactor with a transparent quartz window and a sun-simulator. The present Ni-based catalytic absorbers are more cost effective than conventional Rh/gamma-Al2O3 catalyzed alumina and SiC foam absorbers and the alternative Ru/gamma-Al2O3 catalyzed SiC foam absorbers. Ni/MgO-Al2O3 catalyzed SiC foam absorber, in particular, exhibits superior reforming performance that provides results comparable to that of Rh/gamma-Al2O3 catalyzed alumina foam absorber under a high flux condition or at high temperatures above 1000 degrees C. Ni/MgO-Al2O3 catalyzed SiC foam absorber will be desirable for use in solar receiver reactor systems to convert concentrated high solar fluxes to chemical fuels via endothermic natural-gas reforming at high temperatures. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.ijhydene.2010.04.040

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  • Internally Circulating Fluidized Bed Reactor Using m-ZrO2 Supported NiFe2O4 Particles for Thermochemical Two-Step Water Splitting 査読

    Nobuyuki Gokon, Hiroki Yamamoto, Nobuyuki Kondo, Tatsuya Kodama

    JOURNAL OF SOLAR ENERGY ENGINEERING-TRANSACTIONS OF THE ASME   132 ( 2 )   021102-1 - 021102-10   2010年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ASME  

    A windowed internally circulating fluidized bed reactor was tested using m-ZrO2-supported NiFe2O4 (NiFe2O4/m-ZrO2) particles as redox material for thermochemical two-step water splitting to produce hydrogen from water. The internally circulating fluidized bed of NiFe2O4/m-ZrO2 particles is directly heated by solar-simulated Xe light irradiation through a transparent quartz window mounted on top of the reactor. A sun simulator with three Xe lamps at laboratory scale has been newly installed in our laboratory for testing the fluidized bed reactor. The input power of incident Xe light can be scaled up to 2.6 kW(th). Temperature distributions within the fluidized bed are measured under concentrated Xe light irradiation with an input power of 2.6 kW(th). Hydrogen productivity and reactivity for the fluidized bed of NiFe2O4/m-ZrO2 particles are examined using two different reactors under the N-2 flow rate and flow ratio, which yield a higher bed temperature. The feasibility of successive two-step water splitting using the fluidized bed reactor is examined by switching from N-2 gas flow in the thermal reduction step to a steam/N-2 gas mixture in the water decomposition step. It is confirmed that hydrogen production takes place in the single fluidized bed reactor by successive two-step water splitting. [DOI: 10.1115/1.4001154]

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  • Two-Step Thermochemical Cycles for High-Temperature Solar Hydrogen Production 査読

    Tatsuya Kodama, Nobuyuki Gokon

    Advances in Science and Technology   72   119 - 128   2010年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

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  • MOLTEN-SALT TUBULAR ABSORBER/REFORMER (MoSTAR) PROJECT: REFORMING PERFORMANCE OF REACTOR TUBES DURING INTERMITTENT HEATING 査読

    Nobuyuki Gokon, Tatsuya Kodama, Shingo Yamashita, Tsuyoshi Hatamachi, Taebeom Seo

    ES2010: PROCEEDINGS OF ASME 4TH INTERNATIONAL CONFERENCE ON ENERGY SUSTAINABILITY, VOL 2   105 - 113   2010年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:AMER SOC MECHANICAL ENGINEERS  

    Reforming performances for the double-walled reactor tubes with Na2CO3/MgO composite thermal storage was examined by an intermittent heating The intermittent heating of the reactor tubes is composed of the heat-discharge (or cooling) mode and the subsequent heating mode. The heat-discharging mode simulates a fluctuating Insolation for cloud passages The heating mode simulates a heating of reactor due to concentrated solar radiation by using an electric furnace. The internal tube of the reactor was packed with the 2wt%Ru/Al2O3 catalyst balls while the thermal storage materials were filled in the annular region of the reactor tubes The reactor was heated up to 920 degrees C in the cylindrical electric furnace and the CH4/CO2 mixture was fed into the internal catalyst tube at gas hourly space velocity (GHSV) of 12500 h(-1).
    Through the cooling mode and the subsequent heating mode, temperature variations of reactor tubes, catalyst and composite material, H-2/CO ratio variations of effluent gas from the reactor, higher heating value (HHV) power of reformed gas were respectively examined for the double-walled reactor tubes and a single-wall reactor tube without the thermal storage.

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  • Molten-salt tubular absorber/reformer (MoSTAR) project: NaCl/MgO composite thermal storage for double-walled reactor tubes 査読

    Nobuyuki Gokon, Shingo Yamashita, Shogo Takahashi, Tatsuya Kodama, Taebeom Seo

    SolarPACES2010, Perpinan, France, September 21-25 2010.   2010年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • 5kWth-solar demonstration of a ferrite foam device reactor for thermochemical two-step water-splitting 査読

    Tatsuya Kodama, Taebeom Seo, Nobuyuki Gokon, Ju Han Lee, Sang Joon Oh, Koichi Sakai, Nobuki Imaizumi

    SolarPACES2010, Perpinan, France, September 21-25 2010.   2010年

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  • 4-2-3 5kW太陽集光器によるフェライト担持発泡体デバイスの水熱分解試験(4-2 太陽熱発電・水素製造2,Session 4 新エネルギー,研究発表)

    今泉 伸樹, 佐藤 直樹, 籏町 剛, 郷右近 展之, 児玉 竜也, SEO Taebeom

    日本エネルギー学会大会講演要旨集   19   232 - 233   2010年

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    記述言語:日本語   出版者・発行元:一般社団法人日本エネルギー学会  

    We have developed ferrite-coated foam devices for solar thermochemical two-step water-splitting to produce hydrogen from water. The reactivity of the foam device was firstly tested by 1 kW solar simulator at a laboratory scale experiment. Hydrogen was continuously produced for 20 cycles. Then, the foam device was tested by 5 kW dish type solar concentrator in Inha University in Korea. As a result, solar hydrogen production was demonstrated for several cycles.

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  • 4-2-2 二段階水熱分解セラミックの高活性化に関する研究(4-2 太陽熱発電・水素製造2,Session 4 新エネルギー,研究発表)

    青柳 大樹, 掛布 綾香, 郷右近 展之, 児玉 竜也

    日本エネルギー学会大会講演要旨集   19   230 - 231   2010年

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    記述言語:日本語   出版者・発行元:一般社団法人日本エネルギー学会  

    Reactive ceramic was studied as a redox material for converting high-temperature heat into chemical fuels via solar two-step thermochemical water-splitting. In the present study, cyclic reactivity of reactive ceramic such as, Fe-containing YSZ particles was examined using thermal reduction temperatures of 1400-1500°C.

    DOI: 10.20550/jietaikaiyoushi.19.0_230

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  • 4-2-4 石英窓型ソーラー改質器のためのNi系触媒デバイスの開発(4-2 太陽熱発電・水素製造2,Session 4 新エネルギー,研究発表)

    山脇 悠平, 嶋脇 一賢, 郷右近 展之, 児玉 竜也

    日本エネルギー学会大会講演要旨集   19   234 - 235   2010年

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    記述言語:日本語   出版者・発行元:一般社団法人日本エネルギー学会  

    Catalytically-activated ceramic foam device has been developed as a solar receiver/absorber for use in methane reforming under concentrated solar radiation as an energy source. Ni-Mg-O and Ni/MgO-Al_2O_3 catalysts were loaded on the SiC ceramic foam. They were examined on activity in CO_2 reforming of methane under solar -simulated Xe light radiation by a windowed reformer.

    DOI: 10.20550/jietaikaiyoushi.19.0_234

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  • Molten-Salt Tubular Absorber/Reformer (MoSTAR) Project: The Thermal Storage Media of Na2CO3-MgO Composite Materials 査読

    Tatsuya Kodama, Nobuyuki Gokon, Shin-ichi Inuta, Shingo Yamashita, Taebeom Seo

    JOURNAL OF SOLAR ENERGY ENGINEERING-TRANSACTIONS OF THE ASME   131 ( 4 )   041013-1 - 041013-8   2009年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ASME  

    The molten-salt tubular absorber/reformer (MoSTAR) project aims to develop a novel type of "double-walled" tubular absorber/reformer with molten-salt thermal storage at high temperature for use in solar natural-gas reforming and solar air receiver, and to demonstrate its performances on the sun with a 5 kW(t) dish-type solar concentrator. The new concept of double-walled reactor tubes is proposed for use in a solar reformer by Niigata University, Japan, and involves packing a molten/ceramic composite material in the annular region between the internal catalyst tube and the exterior solar absorber wall. This solar tubular absorber concept may be also applied to solar air receiver for solar thermal power generation. The MoSTAR project includes the development of molten-salt thermal storage media, the new design and the fabrication of absorber/reformer with the double-walled absorber tubes, and finally the solar demonstration on the 5 kW(t) dish concentrator of Inha University in Korea. In this paper, thermal storage media of the series of Na2CO3-MgO composite materials were tested in a double-walled reformer tube with a thermal storage capacity of about 0.3 kWh. The chemical reaction performances for dry reforming of methane during cooling or heat-discharge mode of the reactor tube were investigated using an electric furnace. The experimental results obtained under feed gas mixture of CH4/CO2=1:3 at a residence time of 0.3 s and at 1 atm showed that the single reactor tube with 90 wt % Na2CO3/10 wt % MgO composite material successfully maintained a high methane conversion above 90% with about 0.9 kW reforming scale based on high heating value during 45 min of the heat-discharge mode. The chemical reaction performances of the reactor tube were investigated also for the solar-simulating operation mode. The application of the new reactor tubes to solar tubular reformers is expected to help realize stable operation of the solar reforming process under fluctuating insolation during a cloud passage.

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  • Double-walled reformer tubes using high-temperature thermal storage of molten-salt/MgO composite for solar cavity-type reformer 査読

    Nobuyuki Gokon, Shin-ichi Inuta, Shingo Yamashita, Tsuyoshi Hatamachi, Tatsuya Kodama

    INTERNATIONAL JOURNAL OF HYDROGEN ENERGY   34 ( 17 )   7143 - 7154   2009年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Composite materials with alkali carbonate and magnesia have been examined for high-temperature thermal storage in solar tubular reformers. The concept of a double-walled reactor tube involves packing a molten-salt/ceramic composite material into the annular region between internal catalyst tube and exterior solar-absorber wall. In this paper, the shape and interior structure of the reactor tube are newly designed for use in solar cavity-type reformers using straight reactor tubes. Na2CO3, K2CO3, and Li2CO3 composite materials with magnesia were tested as thermal storage media for CO2 reforming of methane during cooling mode of the reactor tube at a laboratory scale. The efficiency of Na2CO3/MgO composite with various MgO contents was also estimated. Composite materials of Na2CO3 80-90 wt% and MgO 20-10 wt% were successfully delayed the cooling of the catalyst bed and sustained methane conversion at &gt;90%. A solar cavity-type reformer consisting of multiple straight reactor tubes is expected to enable stable operation of the solar reforming process under fluctuating solar insolation during cloud passage. (C) 2009 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.ijhydene.2009.06.047

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  • Thermochemical two-step water splitting cycles by monoclinic ZrO2-supported NiFe2O4 and Fe3O4 powders and ceramic foam devices 査読

    Nobuyuki Gokon, Hiroko Murayama, Ayumi Nagasaki, Tatsuya Kodama

    SOLAR ENERGY   83 ( 4 )   527 - 537   2009年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    A thermochemical two-step water splitting cycle is examined for NiFe2O4 and Fe3O4 supported on monoclinic ZrO2 (NiFe2O4/m-ZrO2 and Fe3O4/m-ZrO2) in order to produce hydrogen from water at a high-temperature. The evolution of oxygen and hydrogen by m-ZrO2-supported ferrite powders was studied, and reproducible and stoichiometric oxygen/hydrogen productions were demonstrated through a repeatable two-step reaction. Subsequently, a ceramic foam device coated with NiFe2O4/m-ZrO2 powder was made and examined as a water splitting device by the direct irradiation of concentrated Xe-light in order to simulate solar radiation. The reaction mechanism of the two-step water splitting cycle is associated with the redox transition of ferrite/wustite on the surface of m-ZrO2. A hydrogen/oxygen ratio for these redox powder systems exhibited good reproducibility of approximately two throughout the repeated cycles. The foam device loaded NiFe2O4/m-ZrO2 powder was also successful with respect to hydrogen production through 10 repeated cycles. A ferrite conversion of 24-76% was obtained over an irradiation period of 30 min. (C) 2008 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.solener.2008.10.003

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  • New Solar Water-Splitting Reactor With Ferrite Particles in an Internally Circulating Fluidized Bed 査読

    Nobuyuki Gokon, Shingo Takahashi, Hiroki Yamamoto, Tatsuya Kodama

    JOURNAL OF SOLAR ENERGY ENGINEERING-TRANSACTIONS OF THE ASME   131 ( 1 )   2009年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ASME-AMER SOC MECHANICAL ENG  

    The thermal reduction of metal oxides as part of a thermochemical two-step water-splitting cycle requires the development of a high-temperature solar reactor operating at 1000-1500 degrees C. Direct solar energy absorption by metal-oxide particles provides direct efficient heat transfer to the reaction site. This paper describes the experimental results of a windowed small reactor using an internally circulating fluidized bed of reacting metal-oxide particles under direct solar-simulated Xe-beam irradiation. Concentrated Xe-beam irradiation directly heats the internally circulating fluidized bed of metal-oxide particles. NiFe(2)O(4)/m-ZrO(2) (Ni-ferrite on zirconia support) particles are loaded as the working redox material and are thermally reduced by concentrated Xe-beam irradiation. In a separate step, the thermally reduced sample is oxidized back to Ni-ferrite with steam at 1000 degrees C. The conversion efficiency of ferrite reached 44% (+/- 1.0%), which was achieved using the reactor at 1 kW of incident Xe lamp power. The effects of preheating temperature and NiFe(2)O(4)/m-ZrO(2) particle size on the performance of the reactor for thermal reduction using an internally circulating fluidized bed were evaluated.

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  • Monoclinic zirconia-supported Fe3O4 for the two-step water-splitting thermochemical cycle at high thermal reduction temperatures of 1400-1600 degrees C 査読

    Nobuyuki Gokon, Hiroko Murayama, Jun Umeda, Tsuyoshi Hatamachi, Tatsuya Kodama

    INTERNATIONAL JOURNAL OF HYDROGEN ENERGY   34 ( 3 )   1208 - 1217   2009年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Two-step thermochemical water-splitting using monoclinic ZrO2-supported Fe3O4 (Fe3O4/m-ZrO2) for hydrogen production was examined at high thermal reduction temperatures of 1400-1600 degrees C. After thermal reduction of Fe3O4/m-ZrO2, the reduced sample was quenched in liquid nitrogen, and was subsequently subjected to the water-decomposition step at 1000 degrees C. Quenching of the solid sample was conducted for analysis of the chemical reactions, such as phase transitions, occurring at high-temperature. The hydrogen productivity of Fe3O4 on a m-ZrO2 support and the conversion of Fe3O4 to FeO were significantly enhanced with higher thermal reduction temperatures. The Fe3O4-to-FeO conversion reached 60% when the Fe3O4/m-ZrO2 was thermally reduced at 1600 degrees C. The phase transition of m-ZrO2 support to tetragonal ZrO2 (t-ZrO2) did not occur during the thermal reduction at 1400-1500 degrees C, but it did proceed slightly at 1600 degrees C. Fe ions from Fe3O4 did not enter the ZrO2 lattice during high-temperature thermal reduction. Thus, the Fe3O4 loaded on a m-ZrO2 support can continuously contribute as a Fe3O4-FeO redox reactant for thermochemical water-splitting at high-temperatures of 1400-1600 degrees C. (C) 2008 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.ijhydene.2008.12.007

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  • Kinetics of CO2 reforming of methane by catalytically activated metallic foam absorber for solar receiver-reactors 査読

    Nobuyuki Gokon, Yusuke Osawa, Daisuke Nakazawa, Tatsuya Kodma

    INTERNATIONAL JOURNAL OF HYDROGEN ENERGY   34 ( 4 )   1787 - 1800   2009年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Ni-Cr-Al metallic foam absorber with high porosity was catalytically activated using a Ru/gamma-Al2O3 catalyst, and was subsequently tested with respect to CO2 reforming of methane in a small-scale volumetric receiver-reactor by using a sun-simulator. A chemical storage efficiency of 37% was obtained for a mean light flux of 325 kW m(-2). Furthermore, the activity and the stability of the metallic foam absorber were compared with those of a SiC foam absorber activated with the same Ru/gamma-Al2O3 catalyst for 50 h of light irradiation, and it was found that the metallic foam absorber has superior catalytic stability in comparison to the SiC form absorber. In addition, unlike ceramic foams such as SiC, metallic foams feature superior plasticity, which prevents the emergence of cracks caused by mechanical or thermal shock.
    The kinetics of CO2 reforming of methane over Ru/gamma-Al2O3/metallic foams was also examined for temperatures of 600-750 degrees C using a quartz tube reactor and an electric furnace. The experiments were performed by varying the methane/CO2 ratios of 0.3-3.0. Moreover, the kinetic data were fitted to four different types of kinetic models, namely the Langmuir-Hinshelwood, Basic, Eley-Rideal, and Stepwise mechanisms. The kinetic model which provided the best prediction of the experimental reforming rates was the Langmuir-Hinshelwood mechanism for temperatures of 600-700 degrees C. (C) 2008 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.ijhydene.2008.12.018

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  • CO2 reforming of CH4 using molten salt/MgO composite thermal storages for solar hydrogen production 査読

    Nobuyuki Gokon, Shin-ichi Inuta, Shingo Yamashita, Tsuyoshi Hatamachi, Tatsuya Kodama

    International Symposium on Fusion Tech 2009 at Incheon, Incheon, Korea, January 13-15, 2009   2009年

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  • KINETICS OF CO(2) REFORMING OF METHANE BY CATALYTICALLY ACTIVATED METALLIC FOAM ABSORBER FOR SOLAR RECEIVER-REACTORS 査読

    Nobuyuki Gokon, Yusuke Osawa, Daisuke Nakazawa, Tsuyoshi Hatarnachi, Tatsuya Kodama

    ES2008: PROCEEDINGS OF THE 2ND INTERNATIONAL CONFERENCE ON ENERGY SUSTAINABILITY, VOL 2   34 ( 4 )   371 - 383   2009年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:AMER SOC MECHANICAL ENGINEERS  

    Ni-Cr-Al alloy foam absorber with high porosity was catalytically activated using a Ru/gamma-Al(2)O(3) catalyst, and was subsequently tested with respect to CO(2) reforming of methane in a small-scale volumetric receiver-reactor by using a sun simulator. A chemical storage efficiency of about 40% was obtained for a mean light flux of 325 kW m(-2). Furthermore, the activity and the stability of the metallic foam absorber were compared with those of a SiC foam absorber activated with the same Ru/gamma-Al(2)O(3) catalyst for 50 h of light irradiation, and it was found that the metallic foam absorber has superior catalytic stability in comparison to the SiC form absorber. In addition, unlike ceramic foams such as SiC, metallic foams feature superior plasticity, which prevents the emergence of cracks caused by mechanical or thermal shock.
    The kinetics of CO(2) reforming of methane over metallic foam absorbers were also examined for temperatures of 600-750 degrees C using a quartz tube reactor and an electric furnace. The experiments were performed by varying the methane/CO(2) ratios of 0.5-2.3. Moreover, the kinetic data were fitted to four different types of kinetic models, namely the Langmuir-Hinshelwood, Basic, Eley-Rideal, and Stepwise mechanisms. The kinetic model which provided the best prediction of the experimental reforming rates was the Langmuir-Hinshelwood mechanism.

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  • Thermochemical Two-Step Water Splitting by Zirconia-Supported Ferrites and Its foam Device for Solar Demonstration 査読

    Tatsuya Kodama, Nobuyuki Gokon, Juyn Umeda, Kouchi Sakai, Taebeom Seo

    SolarPACES2009, Berlin, Germany, September 15-18 2009.   2009年

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  • Reactive ferrite-coated ceramic foam device for a solar thermochemical hydrogen production 査読

    Ayumi Nagasaki, Tsuyoshi Hatamachi, Nobuyuki Gokon, Tatsuya Kodama

    International Symposium on Fusion Tech 2009 at Incheon, Incheon, Korea, January 13-15, 2009   2009年

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  • Solar thermochemical hydrogen production research in Inha and Niigata Universities collaboration 査読

    Tatsuya Kodama, Nobuyuki Gokon, Ayumi Nagasaki, Taebeom Seo

    International Symposium on Fusion Tech 2009 at Incheon, Incheon, Korea, January 13-15, 2009   2009年

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  • Ferrite-loaded ceramic foam devices prepared by spin-coating method for a Solar Two-Step thermochemical cycle 査読

    Nobuyuki Gokon, Tatsuya Kodama, Ayumi Nagasaki, Ko-ichi Sakai, Tsuyoshi Hatamachi

    ASME 2009 3rd International Conference of Energy Sustainability (ES2009), San Francisco, California, USA, July 19-23, 2009   439 - 449   2009年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

    DOI: 10.1115/ES2009-90172

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  • MOLTEN-SALT TUBULAR ABSORBER/REFORMER (MoSTAR) PROJECT: METAL-PLATE-BRIDGED DOUBLE TUBE REACTOR 査読

    Tatsuya Kodama, Nobuyuki Gokon, Shin-ichi Inuta, Shin-go Yamashita, Tsuyoshi Hatamachi, Taebeom Seo

    ES2009: PROCEEDINGS OF THE ASME 3RD INTERNATIONAL CONFERENCE ON ENERGY SUSTAINABILITY, VOL 2   451 - 457   2009年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:AMER SOC MECHANICAL ENGINEERS  

    The Molten-Salt Tubular Absorber/Reformer (MoSTAR) Project, which is jointly conducted by Niigata University, Japan, and Inha University, Korea, aims to develop a novel-type of "double-walled" tubular absorbers/reformers with molten-salt thermal storage at high temperature for use in solar natural-gas reforming and solar air receiver, and to demonstrate their performances on sun with a 5-kW, dish-type solar concentrator. The new concept of "double-walled" reactor tubes was proposed for use in a solar reformer by Niigata University, Japan, and involves packing a molten salt in the annular region between the internal catalyst tube and the exterior solar absorber tube of the double reactor tube. In this work, "metal-plate-bridged" double reactor tubes are newly proposed for use in a solar reformer. Two different sized reactor tubes are constructed, and tested on chemical reaction performance for dry reforming of methane during cooling or heat-discharge mode of the reactor tube using an electric furnace. The experimental results obtained under feed gas mixture of CH(4)/CO(2) = 1:3 at a residence time of 0.36 s and at 1 atm showed that the double reactor tube with the heat storage medium Na(2)CO(3) in the annular region successfully sustained a high methane conversion above 90% with about 0.7-kW output power of the reformed gas based on HHV for 40 min of the heat-discharge mode. The application of the new reactor tubes to solar tubular reformers is expected to help realize stable operation of the solar reforming process under fluctuating insolation during a cloud passage.

    DOI: 10.1115/ES2009-90230

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  • Internally circulating fluidized bed reactor with NiFe2O4 particles for thermochemical water-splitting 査読

    Nobuyuki Gokon, Nobuyuki Kondo, Tetsuro Mataga, Tatsuya Kodama

    SolarPACES2009, Berlin, Germany, September 15-18 2009.   2009年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • KINETICS OF CO(2) REFORMING OF METHANE BY CATALYTICALLY ACTIVATED METALLIC FOAM ABSORBER FOR SOLAR RECEIVER-REACTORS 査読

    Nobuyuki Gokon, Yusuke Osawa, Daisuke Nakazawa, Tsuyoshi Hatarnachi, Tatsuya Kodama

    ES2008: PROCEEDINGS OF THE 2ND INTERNATIONAL CONFERENCE ON ENERGY SUSTAINABILITY, VOL 2   371 - 383   2009年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:AMER SOC MECHANICAL ENGINEERS  

    Ni-Cr-Al alloy foam absorber with high porosity was catalytically activated using a Ru/gamma-Al(2)O(3) catalyst, and was subsequently tested with respect to CO(2) reforming of methane in a small-scale volumetric receiver-reactor by using a sun simulator. A chemical storage efficiency of about 40% was obtained for a mean light flux of 325 kW m(-2). Furthermore, the activity and the stability of the metallic foam absorber were compared with those of a SiC foam absorber activated with the same Ru/gamma-Al(2)O(3) catalyst for 50 h of light irradiation, and it was found that the metallic foam absorber has superior catalytic stability in comparison to the SiC form absorber. In addition, unlike ceramic foams such as SiC, metallic foams feature superior plasticity, which prevents the emergence of cracks caused by mechanical or thermal shock.
    The kinetics of CO(2) reforming of methane over metallic foam absorbers were also examined for temperatures of 600-750 degrees C using a quartz tube reactor and an electric furnace. The experiments were performed by varying the methane/CO(2) ratios of 0.5-2.3. Moreover, the kinetic data were fitted to four different types of kinetic models, namely the Langmuir-Hinshelwood, Basic, Eley-Rideal, and Stepwise mechanisms. The kinetic model which provided the best prediction of the experimental reforming rates was the Langmuir-Hinshelwood mechanism.

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  • REACTIVITY OF IRON-CONTAINING YSZ FOR A TWO-STEP THERMOCHEMICAL WATER SPLITTING USING THERMAL REDUCTION TEMPERATURES OF 1400-1500 degrees C 査読

    Tatsuya Kodama, Eiji Hiraiwa, Nobuyuki Gokon

    ES2008: PROCEEDINGS OF THE 2ND INTERNATIONAL CONFERENCE ON ENERGY SUSTAINABILITY, VOL 2   361 - 369   2009年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:AMER SOC MECHANICAL ENGINEERS  

    A thermochemical two-step water splitting cycle using a redox system of iron-based oxides or ferrites is one of the promising processes for converting solar energy into clean hydrogen in sunbelt regions. Fe3O4 supported on YSZ (Yttrium-Stabilized Zirconia) or Fe3O4/YSZ is a promising working material for the two-step water splitting cycle. In the water splitting cycle, an iron-containing YSZ or Fe2+-YSZ is formed by a high-temperature reaction between Fe3O4 and YSZ support at 1400 degrees C in an inert atmosphere. The Fe2+-YSZ reacts with steam and generate hydrogen at 1000 degrees C, to form Fe3+-YSZ that is re-activated by a thermal reduction ill a;separate step at 1400 degrees C under an inert atmosphere. In the present work, the thermal reduction was performed in a higher temperature range of 1400-1500 degrees C while the hydrolysis reaction was carried Out at 1000 degrees C. It was confirmed by XRD analysis that the cyclic redox reactions Occurred based on the same reaction mechanism when using a thermal reduction temperature between 1400 and 1500 degrees C. The conversions of Fe3O4 to Fe2+-YSZ were 20, 26 and 47% when the thermal reduction temperature were 1400, 1450, and 1500 degrees C respectively, indicating that the x values in the formed Fe2+-YSZ or Fex2+YyZr1-yO2-y/2+x, were 0.08, 0.11, and 0.19 respectively, where y = 0.15. The conversions of Fe2+-YSZ to Fe3+-YSZ ill the hydrolysis reaction (at 1000 degrees C), however, decreased from 90% to 60% when the thermal reduction temperature increased from 1400 to 1500 degrees C. As the results, the hydrogen production reactivity of Fe3O4 supported on YSZ increased from 5.6 x 10(-4) to 7.5 x 10(-4) g per gram of Fe3O4/YSZ for one cycle on the cycle average by elevated thermal reduction temperature from 1400 to 1500 degrees C.

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  • 4-10-4 フェライト内循環流動層反応器の光照射による二段階水熱分解(4-10 太陽熱発電・水素製造2,Session 4 新エネルギー,研究発表)

    近藤 伸之, 又賀 哲郎, 郷右近 展之, 児玉 竜也

    日本エネルギー学会大会講演要旨集   18   312 - 313   2009年

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    記述言語:日本語   出版者・発行元:一般社団法人日本エネルギー学会  

    A windowed solar chemical reactor with internally-circulating fluidized bed of ferrite particles has been developed for realizing hydrogen production from water via the thermochemical cycle. In this research, unsupported NiFe_2O_4 and m-ZrO_2 supported NiFe_2O_4 were tested for successive two-step water-splitting using the internally-circulating fluidized bed reactor by solar-simulated Xe light irradiation.

    DOI: 10.20550/jietaikaiyoushi.18.0_312

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  • 4-10-1 金属発泡体ソーラー改質触媒に関する研究(4-10 太陽熱発電・水素製造2,Session 4 新エネルギー,研究発表)

    中沢 大輔, 山脇 悠平, 郷右近 展之, 児玉 竜也

    日本エネルギー学会大会講演要旨集   18   306 - 307   2009年

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    記述言語:日本語   出版者・発行元:一般社団法人日本エネルギー学会  

    Catalytically-activated metallic foam device has been developed for methane reforming under direct solar radiation. Ru/γ-Al_2O_3 catalyst was loaded on the metallic foam, and was tested on activity in CO_2 reforming of methane under solar-simulated Xe light irradiation by volumetric reactor. Kinetics of methane reforming with CO_2 was also examined using the foam devices in the temperature range of 750-850℃ by uniform heating using electric furnace.

    DOI: 10.20550/jietaikaiyoushi.18.0_306

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  • 4-9-4 ジルコニア担持フェライトによる二段階水熱分解サイクル機構(4-9 太陽熱発電・水素製造1,Session 4 新エネルギー,研究発表)

    梅田 準, 近藤 建, 郷右近 展之, 児玉 竜也

    日本エネルギー学会大会講演要旨集   18   304 - 305   2009年

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    記述言語:日本語   出版者・発行元:一般社団法人日本エネルギー学会  

    Two-step thermochemical water-splitting cycle were examined on activity and reactivity for NiFe_2O_4/m-ZrO_2 and NiFe_2O_4/c-YSZ using thermal reduction temperatures of 1400-1500℃ for the purpose of converting solar-high temperature heat into hydrogen. In addition, reaction mechanism of two-step water splitting was evaluated for NiFe_2O_4/m-ZrO_2 and NiFe_2O_4/c-YSZ using XRD analysis and chemical analysis.

    DOI: 10.20550/jietaikaiyoushi.18.0_304

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  • 4-10-2 Na_2CO_3/MgOコンポジット蓄熱体を用いたソーラー改質管に関する研究(4-10 太陽熱発電・水素製造2,Session 4 新エネルギー,研究発表)

    山下 真吾, 森 周作, 籏町 剛, 郷右近 展之, 児玉 竜也

    日本エネルギー学会大会講演要旨集   18   308 - 309   2009年

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    記述言語:日本語   出版者・発行元:一般社団法人日本エネルギー学会  

    A solar reformer of the "double-walled" reactor tubes with molten-salt has been developed for carbon dioxide reforming of methane using high-temperature solar heat. Ru/Al_2O_3 catalyst particles were loaded in the inner tube of the double-walled tubular reactor while a mixture of Na_2CO_3 and MgO was loaded as a thermal storage medium into the outer annulus of that. In the present work, variation of insolation due to cloud passage was simulated by intermittent heating, and reforming performances of the reformer tubes were examined.

    DOI: 10.20550/jietaikaiyoushi.18.0_308

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  • Occurrence of Faceting for [110] Symmetric Tilt Boundaries in Cu Doped with Bi 査読

    Nobuyuki Gokon, Masanori Kajihara

    MATERIALS TRANSACTIONS   49 ( 11 )   2584 - 2590   2008年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:JAPAN INST METALS  

    The faceting of the grain boundary in the binary Cu-Bi system was experimentally observed by transmission electron microscopy (TEM). For the observation, Cu bicrystals with Sigma 33, Sigma 9 and Sigma 11[110] symmetric tilt boundaries were doped with Bi at 1173 K for 120 h, and then homogenized at 1173 K for 48 h. followed by furnace cooling or water quenching. The misorientation angle between the [001] directions of the two single-crystals is 20.1 degrees, 39.9 degrees and 50.5 degrees for the Sigma 33, Sigma 9 and Sigma 11 boundaries, respectively. According to the TEM observation, the grain boundary is faceted markedly in the bicrystal with furnace cooling but barely in that with water quenching. Thus, the faceting takes place during furnace cooling but not during homogenization. The faceting was analyzed quantitatively on the basis of the inclination angle dependence of the boundary energy in Cu. The analysis yields that the contribution of the torque term to the faceting is important. Comparing the boundary diffusivities of Bi and Cu in Cu, we may expect that the mobility is much greater for the grain boundary with Bi than for that without Bi. As a result, the faceting during furnace cooling takes place considerably for the grain boundary with Bi but scarcely for that without Bi. [doi: 10.2320/matertrans.MRA2008062]

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  • Thermochemical two-step water-splitting for hydrogen production using Fe-YSZ particles and a ceramic foam device 査読

    Nobuyuki Gokon, Tomoki Hasegawa, Shingo Takahashi, Tatsuya Kodama

    ENERGY   33 ( 9 )   1407 - 1416   2008年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Fe3O4 supported on cubic yttria-stabilized zirconia (Fe3O4/C-YSZ) is proposed as a promising redox material for the production of hydrogen from water via a thermochemical two-step water-splitting cycle. In this study, the evolution of oxygen and hydrogen during the cyclic reaction was examined using Fe3O4/C-YSZ particles in order to demonstrate reproducible and stoichometric oxygen/hydrogen production through a repeatable two-step reaction. Subsequently, a ceramic foam device coated with Fe3O4 and c-YSZ particles was prepared and examined as a thermochemical water-splitting device in a directly irradiated receiver/reactor hydrogen production system. The Fe3O4/C-YSZ system formed a Fe-containing YSZ (Fe-YSZ) by high-temperature reaction between Fe3O4 and the c-YSZ support at 1400 degrees C in an inert atmosphere. The reaction mechanism of the two-step water-splitting cycle is associated with the redox transition of Fe2+-Fe3+ ions in the c-YSZ lattice. The Fe-YSZ particles exhibit good reproducibility for reaction with a hydrogen/oxygen ratio of approximately 2.0 throughout repeated cycles. The foam device coated with Fe-YSZ particles was also successful for continual hydrogen production through 32 repeated cycles. A 20-27% ferrite conversion was obtained using 10.5 wt% Fe3O4 loading over an irradiation period of 60 min. (C) 2008 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.energy.2008.04.011

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  • Fracture behavior of Σ9 [110] asymmetric tilt boundaries in Cu doped with Bi 査読

    N. Gokon, S. Ohyama, M. Kajihara

    Material Science and Engineering A   488 ( 1-2 )   252 - 259   2008年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.msea.2007.11.015

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  • Development of novel magnetic nano-carriers for high-performance affinity purification 査読

    Kosuke Nishio, Yuka Masaike, Morihito Ikeda, Hiroki Narimatsu, Nobuyuki Gokon, Shingo Tsubouchi, Mamoru Hatakeyama, Satoshi Sakamoto, Naohiro Hanyu, Adarsh Sandhu, Haruma Kawaguchi, Masanori Abe, Hiroshi Handa

    COLLOIDS AND SURFACES B-BIOINTERFACES   64 ( 2 )   162 - 169   2008年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE BV  

    We developed novel magnetic nano-carriers around 180 mn in diameter for affinity purification. Prepared magnetic nano-carriers possessed uniform core/shell/shell nano-structure composed of 40 nm magnetite particles/poly(styrene-co-glycidyl methacrylate (GMA))/polyGMA, which was constructed by admicellar polymerization. By utilizing relatively large 40 nm magnetite particles with large magnetization, the magnetic nanocarriers could show good response to permanent magnet. Thanks to uniform polymer shell with high physical/chemical stability, the magnetic nano-carriers could disperse in a wide range of organic solvent without disruption of core/shell structure and could immobilize various kinds of drugs. We examined affinity purification using our prepared magnetic nano-carriers with anti-cancer agent methotrexate (MTX) as ligand. Our magnetic nano-carriers showed higher performance compared to commercially available magnetic beads in terms of purification efficiency of target including extent of non-specific binding protein. (c) 2008 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.colsurfb.2008.01.013

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  • Thermochemical two-step water-splitting reactor with internally circulating fluidized bed for thermal reduction of ferrite particles 査読

    N. Gokon, S. Takahashi, H. Yamamoto, T. Kodama

    INTERNATIONAL JOURNAL OF HYDROGEN ENERGY   33 ( 9 )   2189 - 2199   2008年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    A thermochemical two-step water-splitting cycle using a redox system of iron-based oxides or ferrites was examined on hydrogen productivity and reactivity of ferrite in order to convert solar energy into hydrogen in sunbelt regions. In the present paper, a new concept is proposed for a windowed thermochemical water-splitting reactor, using an internally circulating fluidized bed of NiFe2O4/m-ZrO2 particles, and thermal reduction of the bed is demonstrated on a laboratory scale by using a solar-simulating Xe-beam irradiation. The concept is that concentrated solar radiation passes through the transparent window and directly heats the internally circulating fluidized bed. The fluidized bed reactor enabled the NiFe2O4/M-ZrO2 sample to remain in powder form without sintering and agglomerating during direct Xe-beam irradiation over 30 min. Approximately 45% of the NiFe2O4 was converted to the reduced phase by the solar-simulated high-flux beam, and was then completely reoxidized with steam at 1000 degrees C to generate hydrogen. (c) 2008 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.ijhydene.2008.02.044

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  • Experimental determination of boundary energies of Sigma 9 [110] asymmetric tilt boundaries in Cu 査読

    N. Gokon, A. Kajihara

    MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING   477 ( 1-2 )   121 - 128   2008年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE SA  

    A silica particle observation (SPO) method was used in order to determine experimentally the boundary energies of Sigma 9 [110] asymmetric tilt boundaries with a misorientation angle of theta = 38.9 degrees in Cu for various inclination angles between phi = 0 degrees and 90 degrees. The SPO method has no drawbacks which are inevitable in boundary grooving and tri-junction methods. The boundary energy takes the maximum value at phi = 0 degrees but the minimum value at phi = 65 degrees. The minimum value is 65% of the maximum value. The inclination angle dependence of the boundary energy was utilized to evaluate quantitatively the possibility of faceting and dissociation for the boundary. According to the evaluation, the faceting into the {112} {552} and {552} {112} boundaries is possible for the {778} {110}, {554} {17, 17, 4} and {221} {221} boundaries. Furthermore, the dissociation into the Sigma 3 {111} {111} and {112} {112} twin boundaries is feasible for the {111} {115}, {447} {001} and {778} {110} boundaries. (c) 2007 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.msea.2007.05.029

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  • Application of an internally circulating fluidized bed for windowed solar chemical reactor with direct irradiation of reacting particles 査読

    Tatsuya Kodama, Syu-ichi Enomoto, Tsuyoshi Hatamachi, Nobuyuki Gokon

    JOURNAL OF SOLAR ENERGY ENGINEERING-TRANSACTIONS OF THE ASME   130 ( 1 )   014504-1 - 014504-4   2008年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ASME  

    Solar thermochemical processes require the development of a high-temperature solar reactor operating at 1000-1500 degrees C, such as solar gasification of coal and the thermal reduction of metal oxides as part of a two-step water splitting cycle. Here, we propose to apply "an internally circulating fluidized bed" for a windowed solar chemical reactor in which reacting particles are directly illuminated. The prototype reactor was constructed in a laboratory scale and demonstrated on CO2 gasification of coal coke using solar-simulated, concentrated visible light from a sun simulator as the energy source. About 12% of the maximum chemical storage efficiency was obtained by the solar-simulated gasification of the coke.

    DOI: 10.1115/1.2807213

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  • Iron-containing yttria-stabilized zirconia system for two-step thermochemical water splitting 査読

    Nobuyuki Gokon, Takayuki Minno, Yumiko Nakamuro, Tatsuya Kodama

    JOURNAL OF SOLAR ENERGY ENGINEERING-TRANSACTIONS OF THE ASME   130 ( 1 )   011018-1 - 011018-6   2008年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ASME  

    An iron-containing yttria-stabilized zirconia (YSZ) or Fe-YSZ was found to be a promising working redox material for the thermochemical two-step water-splitting cycle. The Fe-YSZ was formed by a high-temperature reaction between YSZ doped with more than 8 mol % Y2O3 and Fe3O4 supported on the YSZ at 1400 degrees C in an inert atmosphere. The formed Fe-YSZ reacted with steam to generate hydrogen at 1000 degrees C. The oxidized Fe-YSZ was reactivated by a thermal reduction at 1400 degrees C in an inert atmosphere. The alternative O-2 and H-2 generations in the repeated two-step reactions and the X-ray diffraction and chemical analysis studies on the solid materials indicated that the two-step water splitting was associated with a redox transition between Fe2+-Fe3+ ions in the cubic YSZ lattice.

    DOI: 10.1115/1.2807197

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  • Coal Coke gasification in a windowed solar chemical reactor for beam-down optics 査読

    Tatsuya Kodama, Shu-ich Enomoto, Shouta Itoh, Tsuyoshi Hatamachi, Nobuyuki Gokon

    14th Biennial CSP SolarPACES Symposium, LasVegas, Nevada, USA, March 4-7, 2008   2008年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • Thermochemical two-step water splitting by ZrO2-supported NixFe3-xO4 for solar hydrogen production 査読

    T. Kodama, N. Gokon, R. Yamamoto

    SOLAR ENERGY   82 ( 1 )   73 - 79   2008年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    A thermochemical two-step water-splitting cycle using a redox metal oxide was examined for Ni(II) ferrites or NixFe3-xO4 (0 &lt;= x &lt;= 1) for the purpose of converting solar high-temperature heat to hydrogen. The Ni(II) ferrite was decomposed to Ni-doped wustite (NiyFe1-yO) at 1400 degrees C under an inert atmosphere in the first thermal-reduction step of the cycle; it was then reoxidized with steam to generate hydrogen at 1000 degrees C in the second water-decomposition step. Although nondoped Fe3O4 powders formed a nonporous, dense mass of iron oxide by the fusion of FeO and its subsequent solidification after the thermal-reduction step, Ni(II)-ferrite powders were converted into a porous, soft mass after the step. This was probably because Ni doping in the FeO phase raised the melting point of wustite above 1400 degrees C. Supporting the Ni(II) ferrites on m-ZrO2 (monoclinic zirconia) alleviated the high-temperature sintering of iron oxide; as a result, the supported ferrites exhibited greater reactivity and assisted the repeatability of the cyclic water splitting process as compared to the unsupported ferrites. The reactivity increased with the doping value x, and was maximum at x = 1.0 in the NixFe3-xO4/m-ZrO2 system. (C) 2007 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.solener.2007.03.005

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  • High-temperature carbonate/MgO composite materials as thermal storage media for double-walled solar reformer tubes 査読

    N. Gokon, D. Nakano, S. Inuta, T. Kodama

    SOLAR ENERGY   82 ( 12 )   1145 - 1153   2008年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The composite materials of molten alkali-carbonate/MgO-ceramics are examined as thermal storage media in a tubular reformer using a double-walled reactor tube of a laboratory scale. The concept of a double-walled reformer tube is proposed as a solar tubular reformer and involves packing a molten salt/ceramic composite material in the annular region between the internal catalyst tube and the exterior solar absorber wall. The composite materials of Na(2)CO(3), K(2)CO(3), and Li(2)CO(3) with magnesia are tested as thermal storage media. The reforming performances of the composite materials are tested in the cooling mode of the double-walled reactor tube. The experimental result obtained under feed gas mixture of CH(4)/CO(2) = 1:3 at 1 atm shows that the use of 80 wt%Na(2)CO(3)/20 wt%MgO composite material successfully delayed the cooling time of the catalyst bed by 5-19 min in comparison to the case without a composite material. In addition, the Li(2)CO(3)/MgO and Na(2)CO(3)/MgO composite materials relatively revealed good performances: they prolonged the cooling time by over 10 min in the gas hourly space velocity (GHSV) range of 5000-12,500 h(-1). The application of the reactor tubes to solar tubular reformers is expected to realize stable operation of the solar reforming process under fluctuating insolation during cloud passage. (C) 2008 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.solener.2008.05.011

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  • Two-Step Water Splitting By Fe3O4 on Monoclinic Zirconia Support Using Thermal Reduction Temperatures of 1400-1600?C 査読

    Nobuyuki Gokon, Hiroko Murayama, Eiji Hiraiwa, Jun Umeda, Tsuyoshi Hatamachi, Tatsuya Kodama

    14th Biennial CSP SolarPACES Symposium, LasVegas, Nevada, USA, March 4-7, 2008   2008年

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  • 4-7 フェライト/m-ZrO_2粒子の内循環流動層によるソーラー水熱分解((2)太陽熱発電・水素製造2,Session 4 新エネルギー)

    山本 洋樹, 近藤 伸之, 郷右近 展之, 児玉 竜也

    日本エネルギー学会大会講演要旨集   17   208 - 209   2008年

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    記述言語:日本語   出版者・発行元:一般社団法人日本エネルギー学会  

    DOI: 10.20550/jietaikaiyoushi.17.0_208

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  • 4-9 溶融塩蓄熱型ソーラー改質管に関する研究((2)太陽熱発電・水素製造2,Session 4 新エネルギー)

    犬田 進一, 山下 真吾, 原 義則, 籏町 剛, 郷右近 展之, 児玉 竜也

    日本エネルギー学会大会講演要旨集   17   212 - 213   2008年

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    記述言語:日本語   出版者・発行元:一般社団法人日本エネルギー学会  

    DOI: 10.20550/jietaikaiyoushi.17.0_212

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  • 4-4 YSZ担持Fe_3O_4による二段階水分解サイクル((1)太陽熱発電・水素製造1,Session 4 新エネルギー)

    平岩 英治, 梅田 準, 郷右近 展之, 児玉 竜也

    日本エネルギー学会大会講演要旨集   17   202 - 203   2008年

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    記述言語:日本語   出版者・発行元:一般社団法人日本エネルギー学会  

    DOI: 10.20550/jietaikaiyoushi.17.0_202

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  • 4-5 m-ZrO_2担持フェライトによる二段階水分解サイクル((2)太陽熱発電・水素製造2,Session 4 新エネルギー)

    村山 博子, 平岩 英治, 梅田 準, 郷右近 展之, 児玉 竜也

    日本エネルギー学会大会講演要旨集   17   204 - 205   2008年

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    記述言語:日本語   出版者・発行元:一般社団法人日本エネルギー学会  

    DOI: 10.20550/jietaikaiyoushi.17.0_204

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  • Thermochernical cycles for high-temperature solar hydrogen production 査読

    Tatsuya Kodama, Nobuyuki Gokon

    CHEMICAL REVIEWS   107 ( 10 )   4048 - 4077   2007年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER CHEMICAL SOC  

    DOI: 10.1021/cr050188a

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  • Preparation of size-controlled (30-100 nm) magnetite nanoparticles for biomedical applications 査読

    K. Nishio, M. Ikeda, N. Gokon, S. Tsubouchi, H. Narimatsu, Y. Mochizuki, S. Sakamoto, A. Sandhu, M. Abe, H. Handa

    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS   310 ( 2 )   2408 - 2410   2007年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE BV  

    Size-controlled magnetite nanoparticles (MNPs) with several dozen nanometers ( nm) were synthesized for biomedical applications. Nanoparticles of single-phase magnetite, as revealed by X-ray analyses and magnetic measurements, were prepared by oxidizing ferrous hydroxide (Fe(OH)(2)) with a weak oxidant NaNO3 in an N-2-deaerated aqueous NaOH solution ( pH = 12-13) at various temperatures below 37 degrees C. As the synthesis temperature increases from 4 to 37 degrees C, the MNPs are decreased in size (d) from 102 +/- 5.6 to 31.7 +/- 4.9 nm and widened in size distribution, Delta d/d increases from 5.5% to 15%. Prepared without using any surfactant, the MNPs are advantageous for immobilizing functional molecules stably on the surfaces for biomedical applications. (c) 2006 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.jmmm.2006.10.795

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  • Identification of a chemical substructure that is immobilized to ferrite nanoparticles (FP) 査読

    Kosuke Nishio, Nobuyuki Gokon, Makoto Hasegawa, Yuji Ogura, Morihito Ikeda, Hiroki Narimatsu, Masaru Tada, Yuki Yamaguchi, Satoshi Sakamoto, Masanori Abe, Hiroshi Handa

    COLLOIDS AND SURFACES B-BIOINTERFACES   54 ( 2 )   249 - 253   2007年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE BV  

    Despite the wide utility of ferrite nanoparticles (FP), a methodology to conjugate heterologous molecules to FP is still limited and characterization of small molecule-conjugated FP is not well known. Here, we describe what kinds of proteins and amino acids are selectively immobilized onto FP when FP is synthesized in the presence of these molecules. Two-dimentional gel electrophoresis (2D SDS-PAGE) showed that proteins with low pl value were selectively bound to FP. Quantitative analyses using HPLC suggested that L-aspartic acid (Asp) and L-cysteine (Cys) were bound to FP selectively among natural amino acids examined. Additional analysis of compounds-conjugated FP revealed that selective binding of Asp to FP was attributed with its molecular structure. It was found that the substructure of amino acid-bound to FP specifically was composed of a defined chelation of two carboxyl groups separated by two carbon atoms as deduced from FT-IR measurement. Thus, we concluded that molecules possessing two carboxyl groups separated by two carbons were bound to FP spontaneously and selectively, which might enable the attachment of free functional groups onto the FP surface if their molecules have functional groups other than carboxyl groups. The resulting complex might be applicable as a chemical tag to immobilize various molecules onto FP. (C) 2006 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.colsurfb.2006.10.039

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  • Thermochemical Two-Step Water-Splitting Cycle by ZrO2-supported Fe3O4 for Solar Hydrogen Production 査読

    Hiroko Murayama, Shingo Takahashi, Nobuyuki Gokon, Tatsuya Kodama

    The 4th International Symposium on Advanced Materials in Asia-Pacific Rim, Niigata, Niigata, Japan, July 13-15 2007   2007年

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  • A two-step water splitting with ferrite particles and its new reactor concept using an internally circulating fludized-bed 査読

    Nobuyuki Gokon, Takayuki Mizuno, Shingo Takahashi, Tatsuya Kodama

    Proceedings of the ASME International Solar Energy Conference   205 - 214   2007年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:AMER SOC MECHANICAL ENGINEERS  

    A thermochemical two-step water splitting cycle using a redox system of iron-based oxides or ferrites is one of the promising processes for converting and storing solar energy into a fuel in sunbelt regions. The ZrO2-supported ferrite (or the ferrite/ZrO2) powders exhibit superior performances on activity and repeatability of the cyclic reactions when compared to conventional unsupported ferrites. In the first step at 1400 degrees C under an inert atmosphere, ferrite on ZrO2 support is thermally decomposed to the reduced phase of wustite that is oxidized back to ferrite on ZrO2 with steam in a separate second step at 1000 degrees C. In this paper, a number of ZrO2-supporetd ferrites, Mn-, Mg-, Co-, Ni- and Co-Mn-ferrites, are examined on activity. The NiFe2O4/ZrO2 powder was found to have a greatest activity between them. This paper also describes a new concept of a windowed solar chemical reactor using an internally circulating fluidized bed of ferrite/ZrO2 particles. In this concept, concentrated solar radiation passes downwards through the transparent window and directly heats the internally circulating fluidized bed. The exploratory experimental studies on this reactor concept are carried out in a laboratory scale for the thermal decomposition of NiFe2O4/ZrO2 particle bed as part of two-step water splitting cycle.

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  • Solar tubular reformer with molten-salt thermal storage - Design modification of the reactor tube and testing 査読

    Tatsuya Kodama, Tsuyoshi Hatamachi, Daisuke Nakano, Youhei Igarashi, Nobuyuki Gokon

    Proceedings of the ASME International Solar Energy Conference   197 - 204   2007年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:AMER SOC MECHANICAL ENGINEERS  

    For thermal storage in solar tubular reformers, high-temperature composite materials with alkali carbonate and magnesia have been examined. The new concept of "double-walled reactor tube" was previously proposed to use in solar tubular reformers, which involves storing the molten-salt/ceramic composite material in the annular regions between an internal catalyst tube and the exterior solar absorber wall. The shape and structure of the reactor tube can be modified to match with design of a solar tubular reformer. In this paper, the interior structure of the reactor tube has been modified for use in cavity-type reformers using straight reactor tubes. The Na2CO3, K2CO3 and Li2CO3 composite materials with magnesia were prepared, and tested on heat-discharge mode performances for CO2 reforming of methane in the modified reactor tube of a laboratory scale.

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  • Solar Thermochemical Water-Splitting Reactor Using Internally-Fluidized Beds of Ferrite Particles, 査読

    Nobuyuki Gokon, Shingo Takahashi, Hiroki Yamamoto, Tatsuya Kodama

    International Symposium on Fusion Tech 2006-2007 at Niigata, Niigata, Japan, 17-19 January, 2007.   2007年

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  • Reactive Ferrite Devices for Solar Thermochemical Water Splitting 査読

    Tatsuya Kodama, Nobuyuki Gokon

    International Symposium on Fusion Tech 2006-2007 at Niigata, Niigata, Japan, 17-19 January, 2007.   2007年

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  • New solar water-splitting reactor with ferrite particles in an internally circulating fluidized bed 査読

    Nobuyuki Gokon, Shingo Takahashi, Hiroki Yamamoto, Tatsuya Kodama

    PROCEEDINGS OF THE ENERGY SUSTAINABILITY CONFERENCE 2007   131   831 - 839   2007年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:AMER SOC MECHANICAL ENGINEERS  

    The thermal reduction of metal oxides as part of a thermochemical two-step water splitting cycle requires the development of a high temperature solar reactor operating at 1000-15000 degrees C. Direct solar energy absorption by metal-oxide particles provides efficient heat transfer directly to the reaction site. This paper describes experimental results of a windowed thermochemical water-splitting reactor using an internally circulating fluidized bed of the reacting metal-oxide particles under direct solar irradiation. The reactor has a transparent quartz window on the top as aperture. The concentrated solar radiation passes downward through the window and directly heats the internally circulating fluidized bed of metal-oxide particles. Therefore, this reactor needs to be combined with a solar tower or beam down optics.
    NiFe2O4/M-ZrO2 (Ni-ferrite supported on zirconia) particles is loaded as the working redox material in the laboratory scale reactors, and thermally reduced by concentrated Xe-beam irradiation. In a separate step, the thermally-reduced sample is oxidized back to Ni-ferrite with steam at 1000 degrees C. As the results, the conversion of ferrite reached about 44% of maximum value in the reactor by 1 kW of incident solar power. The effects of preheating temperature and particle size of NiFe2O4/m-ZrO2 were tested for thermal reduction of internally circulating fluidized bed in this paper.

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  • Iron-containing YSZ for the Thermochemical Water-Splitting and its Water-Splitting Device 査読

    Tomoki Hasegawa, Yumiko Nakamuro, Nobuyuki Gokon, Tatsuya Kodama

    International Symposium on Fusion Tech 2006-2007 at Niigata, Niigata, Japan, 17-19 January, 2007.   2007年

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  • Catalyst Properties and its Thermal Resistance of Foam Matrix for Methane Reforming under Concentrated Solar Radiation 査読

    Takehiro Shimoyama, Yuusuke Oosawa, Nobuyuki Gokon, Tatsuya Kodama

    International Symposium on Fusion Tech 2006-2007 at Niigata, Niigata, Japan, 17-19 January, 2007.   2007年

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  • Carbonate/Magnesia Composites for Thermal Storage in Solar Tubular Reformers 査読

    Daisuke Nakano, Shinichi Inuta, Youhei Igarashi, Tsuyoshi Hatamachi, Nobuyuki Gokon, Tatsuya Kodama

    International Symposium on Fusion Tech 2006-2007 at Niigata, Niigata, Japan, 17-19 January, 2007.   2007年

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  • Double-Walled Tubular Reactor with Molten Salt Thermal Storage for Solar Reforming of Methane 査読

    Shin-ichi Inuta, Daisuke Nakano, Yoshinori Hara, Nobuyuki Gokon, Tatsuya Kodama

    The 4th International Symposium on Advanced Materials in Asia-Pacific Rim, Niigata, Niigata, Japan, July 13-15 2007   2007年

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  • Reactive Fe-YSZ coated foam devices for solar two-step water splitting 査読

    Tatsuya Kodama, Tomoki Hasegawa, Ayumi Nagasaki, Nobuyuki Gokon

    PROCEEDINGS OF THE ENERGY SUSTAINABILITY CONFERENCE 2007   131 ( 2 )   821 - 829   2007年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:AMER SOC MECHANICAL ENGINEERS  

    A thermochemical two-step water splitting cycle using a redox system of iron-based oxides or ferrites is one of the promising processes for converting solar energy into clean hydrogen in sunbelt regions. An iron-containing YSZ (Yttrium-Stabilized Zirconia) or Fe-YSZ is a promising working redox material for the two-step water splitting cycle. The Fe2+-YSZ is formed by a high-temperature reaction between YSZ, and Fe3O4 supported on the YSZ at 1400 degrees C in an inert atmosphere. The Fe2+-YSZ reacts with steam and generate hydrogen at 1000-1100 degrees C, to form Fe3+-YSZ that is re-activated by a thermal reduction in a separate step at temperatures above 1400 degrees C under an inert atmosphere. In the present work, a ceramic foam coated with the Fe-YSZ particles is examined as the thermochemical water splitting device for use in a solar-directly-irradiated receiver/reactor system. The Fe-YSZ particles were coated on an Mg-partially-stabilized zirconia foam disk and the foam device was tested on the two-step water splitting cycle being performed alternately at temperatures between 1100 and 1400 degrees C. The foam device was irradiated by concentrated visible light from a sun-simulator at the peak flux density of 1000 kW/m(2) and the average flux density of 470 kW/m(2) in a N-2 gas stream, and then, was reacted with steam at 1100 degrees C while heating by an infrared furnace. Hydrogen successfully continued to be produced in the repeated cycles.

    DOI: 10.1115/1.3090819

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  • Reactive Fe-YSZ coated foam devices for solar two-step water splitting 査読

    Tatsuya Kodama, Tomoki Hasegawa, Ayumi Nagasaki, Nobuyuki Gokon

    PROCEEDINGS OF THE ENERGY SUSTAINABILITY CONFERENCE 2007   821 - 829   2007年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:AMER SOC MECHANICAL ENGINEERS  

    A thermochemical two-step water splitting cycle using a redox system of iron-based oxides or ferrites is one of the promising processes for converting solar energy into clean hydrogen in sunbelt regions. An iron-containing YSZ (Yttrium-Stabilized Zirconia) or Fe-YSZ is a promising working redox material for the two-step water splitting cycle. The Fe2+-YSZ is formed by a high-temperature reaction between YSZ, and Fe3O4 supported on the YSZ at 1400 degrees C in an inert atmosphere. The Fe2+-YSZ reacts with steam and generate hydrogen at 1000-1100 degrees C, to form Fe3+-YSZ that is re-activated by a thermal reduction in a separate step at temperatures above 1400 degrees C under an inert atmosphere. In the present work, a ceramic foam coated with the Fe-YSZ particles is examined as the thermochemical water splitting device for use in a solar-directly-irradiated receiver/reactor system. The Fe-YSZ particles were coated on an Mg-partially-stabilized zirconia foam disk and the foam device was tested on the two-step water splitting cycle being performed alternately at temperatures between 1100 and 1400 degrees C. The foam device was irradiated by concentrated visible light from a sun-simulator at the peak flux density of 1000 kW/m(2) and the average flux density of 470 kW/m(2) in a N-2 gas stream, and then, was reacted with steam at 1100 degrees C while heating by an infrared furnace. Hydrogen successfully continued to be produced in the repeated cycles.

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  • New solar water-splitting reactor with ferrite particles in an internally circulating fluidized bed 査読

    Nobuyuki Gokon, Shingo Takahashi, Hiroki Yamamoto, Tatsuya Kodama

    PROCEEDINGS OF THE ENERGY SUSTAINABILITY CONFERENCE 2007   831 - 839   2007年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:AMER SOC MECHANICAL ENGINEERS  

    The thermal reduction of metal oxides as part of a thermochemical two-step water splitting cycle requires the development of a high temperature solar reactor operating at 1000-15000 degrees C. Direct solar energy absorption by metal-oxide particles provides efficient heat transfer directly to the reaction site. This paper describes experimental results of a windowed thermochemical water-splitting reactor using an internally circulating fluidized bed of the reacting metal-oxide particles under direct solar irradiation. The reactor has a transparent quartz window on the top as aperture. The concentrated solar radiation passes downward through the window and directly heats the internally circulating fluidized bed of metal-oxide particles. Therefore, this reactor needs to be combined with a solar tower or beam down optics.
    NiFe2O4/M-ZrO2 (Ni-ferrite supported on zirconia) particles is loaded as the working redox material in the laboratory scale reactors, and thermally reduced by concentrated Xe-beam irradiation. In a separate step, the thermally-reduced sample is oxidized back to Ni-ferrite with steam at 1000 degrees C. As the results, the conversion of ferrite reached about 44% of maximum value in the reactor by 1 kW of incident solar power. The effects of preheating temperature and particle size of NiFe2O4/m-ZrO2 were tested for thermal reduction of internally circulating fluidized bed in this paper.

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  • A Thermochemical Two-Step Water-Splitting Cycle with Magnetite-coated Ceramic Foam Device 査読

    Ayumi Nagasaki, Koichi Sakai, Nobuyuki Gokon, Tatsuya Kodama

    The 4th International Symposium on Advanced Materials in Asia-Pacific Rim, Niigata, Niigata, Japan, July 13-15 2007   2007年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • 4-5 Niフェライト/m-ZrO_2による水熱分解サイクルと内循環流動層反応器の研究((2)太陽熱・未利用熱,Session 4 新エネルギー,研究発表(口頭発表))

    高橋 真悟, 山本 洋樹, 郷右近 展之, 児玉 竜也

    日本エネルギー学会大会講演要旨集   16   256 - 257   2007年

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    記述言語:日本語   出版者・発行元:一般社団法人日本エネルギー学会  

    DOI: 10.20550/jietaikaiyoushi.16.0_256

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  • Ru/Ni-Mg-O catalyzed SiC-foam absorber for solar reforming receiver-reactor 査読

    Tatsuya Kodama, Takuya Moriyama, Takehiro Shimoyama, Nobuyuki Gokon, Hidemasa Andou, Nobuhiro Satou

    JOURNAL OF SOLAR ENERGY ENGINEERING-TRANSACTIONS OF THE ASME   128 ( 3 )   318 - 325   2006年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ASME  

    High-temperature solar reforming of methane with CO2 is investigated using a directly solar-irradiated absorber subjected to a solar mean flux level above 400 kW m(-2) (the peak flux of about 700 kW m(-2)). The new type of catalytically activated ceramic foam absorber-a Ru/Ni-Mg-O catalyzed SiC-foam absorber-was prepared, and its activity was tested in a laboratory-scale volumetric receiver-reactor with a transparent (quartz) window by using a sun-simulator Compared to conventional Rh/Al2O3 catalyzed SiC-foam absorber, this new catalytic absorber is more cost effective and is found to exhibit a superior reaction performance at the high solar flux or at high temperatures, especially above 950 degrees C. This new absorber will be applied in solar receiver-reactor systems for converting concentrated high solar fluxes to chemical fuels via endothermic natural-gas reforming at high temperatures.

    DOI: 10.1115/1.2210497

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  • Direct detection of redox reactions of sulfur-containing compounds on ferrite nanoparticle (FP) surface 査読

    Kosuke Nishio, Nobuyuki Gokon, Shingo Tsubouchi, Morihito Ikeda, Hiroki Narimatsu, Satoshi Sakamoto, Yasuo Izumi, Masanori Abe, Hiroshi Handa

    CHEMISTRY LETTERS   35 ( 8 )   974 - 975   2006年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:CHEMICAL SOC JAPAN  

    Direct observation of sulfur sites for sulfur-containing compounds (cysteine and its oxidative derivatives) on ferrite nanoparticles (FP) was performed by X-ray adsorption near edge structure (XANES) measurements. XANES spectra of cysteine derivatives conjugated with FP indicated that redox reactions occurred on the FP surface. Cysteine was completely oxidized to cystine and cysteinesulfinic acid and cysteic acid were partially reduced. These studies revealed that the FP surface should possess both an oxidation and reduction reactive center for sulfur-containing functional groups.

    DOI: 10.1246/cl.2006.974

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  • Double-walled reactor tube with molten salt thermal storage for solar tubular reformers 査読

    T Hatamachi, T Kodama, Y Isobe, D Nakano, N Gokon

    JOURNAL OF SOLAR ENERGY ENGINEERING-TRANSACTIONS OF THE ASME   128 ( 2 )   134 - 138   2006年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ASME-AMER SOC MECHANICAL ENG  

    This paper proposes a novel-type of "double-walled" reactor tube with molten-salt thermal storage at high temperatures for use in solar tubular reformers. The prototype reactor tube is demonstrated on the heat-discharge and chemical reaction performances during cooling mode of the reactor tube at laboratory scale. The Na2CO3 composite material with MgO ceramics was filled into the outer annulus of the double-walled reactor tube while the Ru-based catalyst particles were filled into the inner tube. The heat discharge form the molten Na2CO3 circumvented the rapid temperature change of the catalyst bed, which resulted in the alleviation of decrease in chemical conversion during cooling mode of the reactor tube. The application of the new reactor tribes to solar tubular reformers is expected to help realize stable operation of the solar reforming process under fluctuating insolation during a cloud passage.

    DOI: 10.1115/1.2183803

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  • Novel Synthetic Clays for Cation Exchange 査読

    T. Kodama, N. Gokon, S. Komarneni

    Advance in Science and Technology   45   209 - 217   2006年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

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  • Ru/Ni-Mg-O catalyzed SiC-foam absorber for solar reforming receiver-reactor 査読

    Tatsuya Kodama, Takuya Moriyama, Takehiro Shimoyama, Nobuyuki Gokon

    Solar Engineering 2005   697 - 705   2006年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:AMER SOC MECHANICAL ENGINEERS  

    High-temperature solar reforming of methane with CO2 is investigated using a directly solar-irradiated 2 absorber subjected to a solar mean flux level above 400 kWm(-2) (the peak flux of about 700 kWm(-2)). The new type of catalytically-activated ceramic foam absorber - an Ru/Ni-Mg-O catalyzed SiC foam absorber - was prepared and its activity was tested in a laboratory-scale volumetric receiver-reactor with a transparent (quartz) window by using a sun-simulator. Compared to conventional Rh/Al2O3 catalyzed SiC foam absorber, this new catalytic absorber is more cost-effective and is found to exhibit a superior reaction performance at the high solar flux or at high temperatures, especially above 950 degrees C. This new absorber will be applied in solar receiver-reactor systems for converting concentrated high solar fluxes to chemical fuels via endothermic natural-gas reforming at the high temperatures.

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  • Iron-containing YSZ (Yttrium-Stabilized Zirconia) system for a two-step thermochemical water splitting 査読

    N. Gokon, T. Mizuno, Y. Nakamuro, T. Kodama

    13th International Symposium on Concentrated Solar Power and Chemical Energy Technologies, Seville Spain, June 20-23, 2006.   2006年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • A new solar chemical reactor with an internally circulating fluidized bed for direct irradiation of reacting particles 査読

    T. Kodama, S. Enomoto, T. Hatamachi, N. Gokon

    13th International Symposium on Concentrated Solar Power and Chemical Energy Technologies, Seville Spain, June 20-23, 2006.   2006年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • Double-walled reactor tube with molten salt thermal storage for solar tubular reformers 査読

    T. Hatamachi, T. Kodama, Y. Isobe, D. Nakano, N. Goukon

    Solar Engineering 2005   691 - 695   2006年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:AMER SOC MECHANICAL ENGINEERS  

    This paper proposes a novel type of "double-walled" reactor tube with molten-salt thermal storage at high temperatures for use in solar tubular reformers. The prototype reactor tube is demonstrated on the heat-discharge and chemical reaction performances during cooling mode of the reactor tube at laboratory scale. The Na2CO3 composite material with MgO ceramics was filled into the outer annulus of the double-walled reactor tube while the Ru-based catalyst particles were filled into the inner tube. The heat discharge form the molten Na2CO3 circumvented the rapid temperature change of the catalyst bed, which resulted in the alleviation of decrease in chemical conversion during cooling mode of the reactor tube. The application of the new reactor tubes to solar tubular reformers is expected to help realize stable operation of the solar reforming process under fluctuating insolation during a cloud passage.

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  • 4-5.フェライト/m-ZrO2の内循環流動方式による太陽熱水分解((2)太陽熱,Session 4 新エネルギー)

    郷右近 展之, 高橋 真悟, 水野 隆之, 児玉 竜也

    日本エネルギー学会大会講演要旨集   15   279 - 280   2006年

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    記述言語:日本語   出版者・発行元:一般社団法人日本エネルギー学会  

    DOI: 10.20550/jietaikaiyoushi.15.0_279

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  • Solar thermochemical process for hydrogen production using ferrites 査読

    H Kaneko, N Gokon, N Hasegawa, Y Tamaura

    ENERGY   30 ( 11-12 )   2171 - 2178   2005年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    A two-step water splitting process using the ZnFe2O4/Zn/Fe3O4 reaction system was proposed for H-2 generation utilizing concentrated solar heat. The mixture of Zn and Fe3O4 was heated to 873 K in flowing steam with an Ar carrier gas, and the H2 gas was generated at 93.4% of the theoretical yield for the reaction of 3Zn+2Fe(3)O(4)+ 4H(2)O=3ZnFe(2)O(4)+4H(2) (H-2 generation step). The XRD and Mossbauer spectroscopy showed that the Zn-submitted ferrite (ZnxFe3-xO4; 0.2 &lt;= x &lt;= 1) (main solid product) and ZnO (minor) were formed in the solid products after the H-2 generation reaction. The ZnFe2O4 product, which was formed after the H-2 generation step during the two-step water splitting process with the ZnFe2O4/Zn/Fe3O4 system, could be decomposed into Zn (and ZnO) and Fe3O4 by the Xe beam irradiation at 1900 K after 3 min with a 67.8% yield for the reaction of 3ZnFe(2)O(4) = 3Zn + 2Fe(3)O(4) + 2O(2) (O-2 releasing step = solar thermal step). (c) 2004 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.energy.2004.08.020

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  • Novel Medical Ferrite Nanobeads with Bioactive Molecules Immobilized Strongly onto the Surfaces 査読

    Masanori Abe, Nobuhiro Matsushita, Masaru Tada, Nobuyuki Gokon, Kosuke Nishio, Hiroshi Handa

    Material Research Society Symposium, San francisco, U.S.A., March 28-April 1, 2005.   2005年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • Polymer coating of ferrite nanoparticles by using “connecter” chemical compounds” 査読

    Shingo Tsubouchi, Kosuke Nishio, Morihito Ikeda, Hiroki Narimatsu, Mamoru Hatakeyama, Nobuyuki Gokon, Hiroshi Handa

    International Conference on Ferrite, San francisco, U.S.A. August 23-27, 2004.   449 - 454   2005年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • 4-5.二段階水熱分解性フェライトへのNiドープ効果と反応デバイス化((2)太陽熱と太陽電池1,Session 4 新エネルギー)

    水野 隆之, 長谷川 知貴, 郷右近 展之, 児玉 竜也

    日本エネルギー学会大会講演要旨集   14   234 - 235   2005年

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    記述言語:日本語   出版者・発行元:一般社団法人日本エネルギー学会  

    DOI: 10.20550/jietaikaiyoushi.14.0_234

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  • Solar hydrogen generation with H2O/ZnO/MnFe2O4 system 査読

    M Inoue, N Hasegawa, R Uehara, N Gokon, H Kaneko, Y Tamaura

    SOLAR ENERGY   76 ( 1-3 )   309 - 315   2004年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The hydrogen generation reaction in the H2O/ZnO/MnFe2O4 system was studied to clarify the possibility of whether this reaction system can be used for the two-step water splitting to convert concentrated solar heat to chemical energy of H-2. At 1273 K, the mixture of ZnO and MnFe2O4 reacted with water to generate H-2 gas in 60% yield. X-ray diffractometry and chemical analysis showed that 48 mol% of Mn-II (divalent manganese ion) in the A-site of MnFe2O4 was substituted with Zn-II (divalent zinc ion) and that chemical formula of the solid product was estimated to be (Zn0.58Mn0.42Mn0.39Fe1.61O4)-Mn-II-Fe-III (Mn-III : trivalent manganese ion). Its lattice constant was smaller than that of the MnFe2O4 (one of the two starting materials). From the chemical composition, the reaction mechanism of the H-2 generation with this system was discussed. Since the Mn ions in the product solid after the H-2 generation reaction are oxidized to Mn3+, which can readily release the O2- ions as O-2 gas around 1300 K, the two-step of H-2 generation and O-2 releasing seem to be cyclic. (C) 2003 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.solener.2003.08.033

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  • Synthesis of monodisperse ferrite nanoparticles coated with polyacrilic acid (PAA) 査読

    K. Nishio, M. Hasegawa, M. Ikeda, H. Narimatsu, Y. Hase, Y. Ogura, N. Gokon, S. Tsubouchi, M. Hatakeyama, M. Abe, H. Handa

    Transactions of the Materials Research Society of Japan   29 ( 4 )   1659 - 1662   2004年

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  • Decomposition of Zn-ferrite for O-2 generation by concentrated solar radiation 査読

    H Kaneko, T Kodama, N Gokon, Y Tamaura, K Lovegrove, A Luzzi

    SOLAR ENERGY   76 ( 1-3 )   317 - 322   2004年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The O-2 generation step in two-step water splitting with Zn-ferrite/Zn, Fe3O4 system was studied with a stainless steel reactor having a window of quartz glass plate (Sandwich Reactor) using the 15 kW solar dish concentrator in Australian National University. The reactant flat layer with a small thickness in the Sandwich Reactor was assumed to simulate the flow section of the particle cloud reactor. The temperature of the sample attained 1750 K in a few minutes by concentrated solar radiation, and 40% molar of the Zn-ferrite was decomposed into Fe3O4 to produce Zn0.4Fe2.6O4, which is the solid solution between ZnFe2O4 and Fe3O4. The laboratory experiment with the Xe beam irradiation showed that the Zn-ferrite decomposition reaction proceeds according to (3)/2ZnFe2O4 = (3)/Zn-2 + Fe3O4 + O-2. In the solar furnace experiment, the metal Zn vapor produced according to this equation seems to be deposited on the surface of the inner wall of the reactor, or it seems to recombine with the released O-2, converting to ZnO under the condition without quenching system in the present experimental setup. (C) 2003 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.solener.2003.08.034

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  • Decomposition of Zn-ferrite for O-2 generation by concentrated solar radiation 査読

    H Kaneko, T Kodama, N Gokon, Y Tamaura, K Lovegrove, A Luzzi

    SOLAR ENERGY   76 ( 1-3 )   317 - 322   2004年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The O-2 generation step in two-step water splitting with Zn-ferrite/Zn, Fe3O4 system was studied with a stainless steel reactor having a window of quartz glass plate (Sandwich Reactor) using the 15 kW solar dish concentrator in Australian National University. The reactant flat layer with a small thickness in the Sandwich Reactor was assumed to simulate the flow section of the particle cloud reactor. The temperature of the sample attained 1750 K in a few minutes by concentrated solar radiation, and 40% molar of the Zn-ferrite was decomposed into Fe3O4 to produce Zn0.4Fe2.6O4, which is the solid solution between ZnFe2O4 and Fe3O4. The laboratory experiment with the Xe beam irradiation showed that the Zn-ferrite decomposition reaction proceeds according to (3)/2ZnFe2O4 = (3)/Zn-2 + Fe3O4 + O-2. In the solar furnace experiment, the metal Zn vapor produced according to this equation seems to be deposited on the surface of the inner wall of the reactor, or it seems to recombine with the released O-2, converting to ZnO under the condition without quenching system in the present experimental setup. (C) 2003 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.solener.2003.08.034

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  • Photocatalytic effect of ZnO on carbon gasification with CO2 for high temperature solar thermochemistry 査読

    N Gokon, N Hasegawa, H Kaneko, H Aoki, Y Tamaura, M Kitamura

    SOLAR ENERGY MATERIALS AND SOLAR CELLS   80 ( 3 )   335 - 341   2003年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE BV  

    A photocatalytic effect of ZnO on carbon gasification with CO2 was studied using a concentrated Xe beam to enhance the gasification rate in solar/chemical energy conversion process. The sample, activated carbon impregnated with ZnO (5 wt%), was heated at 873 K by a Xe beam irradiation with UV (&lt; 400 nm). The gasification rate at 873 K increased 2 folds in comparison with the Xe irradiation without UV, but, the difference of the rate of CO evolution decreased with the increasing temperature from 873 to 1073 K. The carbothermal reduction of ZnO (ZnO + C --&gt; Zn + CO) proceeded at above 950 K, which was demonstrated by XRD analysis and thermodynamic calculation. These results indicate that the photocatalytic effect of ZnO with the UV irradiation enhance the gasification rate of carbon at low temperature (873 K). (C) 2003 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.solmat.2003.08.016

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  • A high magnetic field effect on the M(II)-substituted magnetite formation (M = Ni, Mn, Co) in the wet process 査読

    N Gokon, N Hasegawa, H Kaneko, T Ohara, Y Tamaura

    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS   256 ( 1-3 )   293 - 300   2003年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE BV  

    The M(II)-substituted magnetite (M = Ni, Co and Mn) formation in the wet process in a high magnetic field from 0 to 8 T generated by a superconducting magnet has been studied at the iron ion concentration of 1500 mg/l and the Fe(II)/ Fe(III) mole ratios (R-f) of 1/2 and 2/1. The particle size of the M(II)-substituted magnetite was about 12 nm at R-f and T about 7 nm at R-f The Ni(II) content of the Ni(II)-substituted magnetite at R-f = 2 was lower than that at R-f=1/2 . In 2 T 2 the Ni(II)-substituted magnetite, the lattice parameter increases with an increase in the magnetic field from 0 to 8 T, indicating that high magnetic fields enhance the formation of the Ni(II)-substituted magnetite (solubility enhancement of Ni(II) to magnetite). Also, the lattice parameter of the Co (II)- substituted magnetite decreased with the increasing magnetic field, however, an increase in the lattice parameter was not found in the Mn(II)-substituted magnetite. The presence of large amounts of vacancies was found in the Ni(II)-substituted magnetite formed in high magnetic fields by XRD and atomic absorption analysis. This result is supported by the experimental result in which the magnetite formed in a high magnetic field tends to adsorb Ni(II) in a high magnetic field, and results in the higher incorporation of Ni(II) into the spinel structure. (C) 2002 Elsevier Science B.V. All rights reserved.

    DOI: 10.1016/S0304-8853(02)00582-6

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  • Synthesis of monodisperse ferrite nanoparticles coated with polyacrilic acid (PAA) 査読

    K. Nishio, M. Hasegawa, M. Ikeda, H. Narimatsu, Y. Hase, Y. Ogura, N. Gokon, M. Abe, H. Handa

    Material Research Society Japan, Yokohama, Japan, 11?13 October 2003.   2003年

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  • Reaction mechanism of H-2 generation for H2O/Zn/Fe3O4 system 査読

    H Kaneko, N Kojima, N Hasegawa, M Inoue, R Uehara, N Gokon, Y Tamaura, T Sano

    INTERNATIONAL JOURNAL OF HYDROGEN ENERGY   27 ( 10 )   1023 - 1028   2002年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Several ideas on the reaction mechanism of H2O/Zn/Fe3O4 water splitting system were considered from the aspect of Zn mobility. The vapor deposition of Zn onto the Fe3O4 surface was confirmed by H-2 generation reaction with Zn and Fe3O4 set separately. XPS measurements suggested that the surface of Fe3O4 is covered by Zn before the reaction with steam. The rapid reaction process has been supported by this Zn deposition, which greatly enlarges the number of sites of Zn/Fe3O4 pair that is ready to react with steam. In order to keep the Zn from vaporizing off the system, the Zn/Fe3O4 mixture was covered with additional Fe3O4 to capture the Zn vapor. This resulted in improved H2 yield of 99.5%. (C) 2002 Published by Elsevier Science Ltd on behalf of the International Association for Hydrogen Energy.

    DOI: 10.1016/S0360-3199(02)00012-5

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  • The magnetic coagulation reaction between paramagnetic particles and iron ions coprecipitates 査読

    N Gokon, A Shimada, N Hasegawa, H Kaneko, Y Tamaura, K Ito, T Ohara

    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS   246 ( 1-2 )   275 - 282   2002年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE BV  

    The relationship between the particle size of iron ion coprecipitates and magnetic coagulation reaction has been studied for application to water purification using magnetic separation system. The Fe(III) phosphate complex (IP) precipitate was used as a paramagnetic substance. At a high magnetic field of 8 T, the IP amount recovered by magnetic separation gradually increased with increasing Fe(III) ion concentration in the solution (by increasing the Fe/P mole ratio). However, at a low magnetic field of 0.8 T, it remained constant at about 30%. The magnetic coagulation reaction of the paramagnetic particles of the IP (Fe/P = 1.68) was enhanced by the addition of ferrimagnetic Fe3O4 particles, and that the recovery efficiency became higher with a smaller particle size of Fe3O4. (C) 2002 Elsevier Science B.V. All rights reserved.

    DOI: 10.1016/S0304-8853(02)00074-4

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  • Magnetic coagulation and reaction rate for the aqueous ferrite formation reaction 査読

    N Gokon, A Shimada, H Kaneko, Y Tamaura, K Ito, T Ohara

    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS   238 ( 1 )   47 - 55   2002年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE BV  

    The aqueous ferrite formation reaction with addition of Fe(II) and Fe(111) ions in an alkaline solution in a high magnetic field has been investigated at iron ion concentrations of 150, 750 and 1500 ppm and at Fe(II)/Fe(III) mole ratio of 1 (chemical composition of the stoichiometric Fe3O4) and 2/1 (chemical composition of GR-I In the case of 2 Fe(II)/Fe(III) = 1/2, the magnetic coagulation reaction occurring in the magnetic field range of 0-1 T is different from that in the range of 2-10 T. The higher magnetic field enhanced the reaction rate of the aqueous ferrite formation due to the increase in the intermediate concentration at Fe(II)/Fe(III) = 2/1. The increase in the initial reaction rate can be explained in terms of the increase in the nucleus numbers in the nuclei formation period. (C) 2002 Elsevier Science B.V. All rights reserved.

    DOI: 10.1016/S0304-8853(01)00703-X

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  • Water Splitting by Using a Metal Oxide for Solar Thermal/Chemical Energy Conversion 査読

    Hiroshi Kaneko, Nobuyuki Gokon, Noriko Hasegawa, Masafumi Inoue, Reiko Uehara, Yutaka Tamaura

    Eco-Engineering   14 ( 4 )   3 - 9   2002年

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    記述言語:英語   出版者・発行元:生態工学会  

    Two-step water splitting with Zn/Fe<SUB>3</SUB>O<SUB>4</SUB> - ZnFe<SUB>2</SUB>O<SUB>4</SUB> reaction system is suggested for H<SUB>2</SUB> generation to utilize concentrated solar heat. When mixture of Zn and Fe<SUB>3</SUB>O<SUB>4</SUB> was heated to 873 K and steam was passed through, the H<SUB>2</SUB> was obtained in 93.4% of the theoretical yield. Formation of ZnFe<SUB>2</SUB>O<SUB>4</SUB> with several zinc content (Zn<SUB>x</SUB>Fe<SUB>3-x</SUB>O<SUB>4</SUB>; 0.2&le;x&le;l) and ZnO was determined by XRD and M&ouml;ssbauer spectroscopy. The yield of ZnO was 26-29%, which shows the ratio of the competition-reaction (H<SUB>2</SUB>O Zn system) effects less in the total H<SUB>2</SUB> yield. O<SUB>2</SUB> generation (also energy storage) step can be proceeded at the temperature of ca. 1800 K. The reaction took place very fast, and it can be seen that a large amount of O<SUB>2</SUB> was released from irradiated ZnFe<SUB>2</SUB>O<SUB>4</SUB>. The stoichiometry and the reaction mechanism of the system are discussed upon the analyses for the solid product.

    DOI: 10.11450/seitaikogaku.14.4_3

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  • フェリ磁性体を用いた環境水中のリン及び重金属イオンの磁気分離 査読

    郷右近 展之, 島田 綾乃, 長谷川 紀子, 金子 宏, 小原 健司, 玉浦 裕

    水環境学会誌   25 ( 1 )   33 - 38   2002年

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Japan Society on Water Environment  

    To develop a practical environmental protection technology for purification of lakes, ponds and arm of the sea, an efficient magnetic separation system for phosphate and heavy metal ions removal was studied using ferrimagnetic fine particles (FMFP), which can be prepared from Fe<sup>2+</sup> and Fe<sup>3+</sup> ions in the alkali aqueous solution. With the Fe<sup>3+</sup> ions of 15 mg·<i>l</i><sup>-1</sup> (without addition of FMFP), the phosphate ion recovery decreased from 80% to 20% with decreasing the magnetic field from H=8T to 0.8T. By addition of the FMFP of 5 mg·<i>l</i><sup>-1</sup> along with the Fe<sup>3+</sup> ions of 15 mg·<i>l</i><sup>-1</sup>, above 95% recovery was achieved in a wide range of the magnitude of magnetic field (H=0.8-8T). In case of using cadmium ion instead of the phosphate ion, addition of the FMFP of 5 mg·<i>l</i><sup>-1</sup> together with the Fe<sup>3+</sup> ions of 20 mg·<i>l</i><sup>-1</sup> enhanced recovery of the Cd<sup>2+</sup> ion. We demonstrated that in the presence of the FMFP all of the heavy metal ions were recovered 80% yields or more. These would come from a high magnetic gradient characteristically generated on the surface of FMFP, which results in the enhancement of the magnetic coagulation of the complex with the phosphate or the heavy metal ions and the Fe<sup>3+</sup> ions.

    DOI: 10.2965/jswe.25.33

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    その他リンク: https://jlc.jst.go.jp/DN/JALC/00155190656?from=CiNii

  • Methane reforming with CO2 in molten salt using FeO catalyst 査読

    N Gokon, Y Oku, H Kaneko, Y Tamaura

    SOLAR ENERGY   72 ( 3 )   243 - 250   2002年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Methane dry reforming with CO2 using FeO powder in molten salt has been investigated at various flow rates of CH4/CO3 mixed gases (CH4/CO2 = 1) between 50 and 400 ml/min at 1223 K in an infrared furnace. This work is carried out to determine the usefulness of this method for the chemical storage of solar energy. The CH4/CO2 mixed gases passing through the molten salt (Na2CO3/K2CO3 = 1) containing the FeO powder were catalytically decomposed into CO, H-2 and H2O. The product gas mole ratios, CO/H-2/H2O, were shown to be 3:1:1 for a high flow rate of 200 ml/min and to be CO/H-2 = 2:1 for a low flow rate of 50 ml/min. The results were explained in terms of the kinetics of the CH4-reforming reaction and the thermodynamics of the redox process of FeO powder mixed in the molten salt;
    CH4 + 2FeO double right arrow 2Fe + H-2 + CO + H2O
    Fe + CO2 double right arrow FeO + CO
    for a high How rate, and
    FeO + CH4 double right arrow Fe + 2H(2) + CO
    Fe + CO4 double right arrow FeO + CO
    for a low flow rate. (C) 2002 Elsevier Science Ltd. All rights reserved.

    DOI: 10.1016/S0038-092X(01)00097-4

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  • Thermodynamic study based on the phase diagram of the Na2O-MnO-Fe2O3 system for H-2 production in three-step water splitting with Na2CO3/MnFe2O4/Fe2O3 査読

    H Kaneko, Y Ochiai, K Shimizu, Y Hosokawa, N Gokon, Y Tamaura

    SOLAR ENERGY   72 ( 4 )   377 - 383   2002年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The phase diagram of the Na2O-MnO-Fe2O3 system forms the basis for thermodynamic consideration of H-2 production in water splitting with the Na2CO3/MnFe2O4/Fe2O3 system. Sodium iron manganese oxides Na0.7-1 (Mn1-x, Fe-x)O2+delta. were observed in the phase diagram at T = 1273 K under P-O2 = 1.23 X 10(-5) atm. Confirmation of this phase, especially for x &gt; 0.5, suggests the possibility of H-2 generation under this oxygen partial pressure and results in a value of 1:37 for the ratio of P-H2:P-H2O in the H-2 generation step of water splitting. This oxygen partial pressure is realized by the decomposition of carbon dioxide (CO2 = CO + 0.5O(2)) and it is concluded that the H-2 generation step can proceed under CO2 atmosphere. (C) 2002 Elsevier Science Ltd. All rights reserved.

    DOI: 10.1016/S0038-092X(02)00012-9

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  • 強磁場におけるFe2+ / Fe3+懸濁溶液を用いた湿式フェライト生成反応 査読

    郷右近 展之, 長谷川 紀子, 金子 宏, 玉浦 裕, 小原 健司

    粉体および粉末冶金   49 ( 8 )   710 - 716   2002年

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.2497/jjspm.49.710

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  • Ferrimagnetic coagulation process for phosphate ion removal using high-gradient magnetic separation 査読

    N Gokon, A Shimada, N Hasegawa, H Kaneko, M Kitamura, Y Tamaura

    SEPARATION SCIENCE AND TECHNOLOGY   37 ( 16 )   3781 - 3791   2002年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:MARCEL DEKKER INC  

    An efficient magnetic separation system for phosphate ion removal has been studied for developing a practical environmental protection technology for water purification in rivers, lakes, etc. using ferrimagnetic fine particles (FMFPs), which can be prepared from FeCl2 and FeCl3,aqueous solutions. With 15 mg/L of FeCl3 solution, without the addition of FMFP, phosphate ion recovery increased from 20 to 80% with increasing magnetic field from 0.8 to 8 T. By the addition of 5 mg/L of FMFP with 15 mg/L of FeCl3 solution, above 95% recovery was achieved in a wide range of magnetic field (H = 0.8-8 T). A high magnetic field gradient generated in the vicinity of steel wool caused the enhancement of the magnetic coagulation of the complex with phosphate ion and Fe(III) ion, and the paramagnetic iron-phosphate complexes were attracted to FMFP in the reactor, which resulted in high (95%) recovery in a wide range of magnetic fields.

    DOI: 10.1081/SS-120014831

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  • Studies on metal oxides suitable for enhancement of the O-2-releasing step in water splitting by the MnFe2O4-Na2CO3 system 査読

    H Kaneko, Y Hosokawa, N Kojima, N Gokon, N Hasegawa, M Kitamura, Y Tamaura

    ENERGY   26 ( 10 )   919 - 929   2001年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Reactivities of three metal oxides (Fe2O3, TiO2 and MnO2) with Na2CO3, and of their reaction products with CO2, have been studied to enhance the O-2-releasing step in the two-step water splitting by the MnFe2O4-Na2CO3 system. X-ray diffraction analysis and thermogravimetric measurements showed that the reaction of alpha -Fe2O3 with Na2CO3 (mole ratio=1:1) completed within 10 min at 1073 K to produce NaFeO2 (Fe2O3+Na2CO3--&gt; NaFeO2+CO2). Also, the regeneration of Fe2O3 and Na2CO3 proceeded readily by passing CO2 gas through NaFeO2 (71% yield). TiO2 reacted with Na2CO3 (mole ratio=1:1) at 1073 K for 1 h to form Na8Ti5O14 and Na2TiO3 (93% yield). However, in the reaction of the products with CO2, the starting material (TiO2) was not reproduced at the temperature range from 673 K to 1073 K, but Na4Ti5O12 (having a lower Na content than the form Na8Ti5O14) was formed. In the case of MnO2 with Na2CO3 (mole ratio=2:1), Na0.7MnO2-2.05 and NaMnO2 were produced at 1073 K for 1 h (80% yield), but the reaction between these products and CO2 hardly proceeded. (C) 2001 Elsevier Science Ltd. All rights reserved.

    DOI: 10.1016/S0360-5442(01)00041-X

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  • Stoichiometric studies of H-2 generation reaction for H2O/Zn/Fe3O4 system 査読

    Y Tamaura, N Kojima, N Hasegawa, M Inoue, R Uehara, N Gokon, H Kaneko

    INTERNATIONAL JOURNAL OF HYDROGEN ENERGY   26 ( 9 )   917 - 922   2001年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Water splitting with H2O/Zn/Fe3O4 reaction system is suggested for H-2 generation in order to utilize concentrated solar heat. This system has the possibility of generating more H-2 per 1 mol of Zn than Zn/H2O reaction system at the same temperature, which is noted recently. When a mixture of Zn and FC3O4 was heated to 873 K and steam was passed through, H-2 was obtained in 93.4% of the theoretical yield. The formation of Zn-ferrites with high content of zinc (ZnxFe3-xO4; 0.2 less than or equal to x less than or equal to 1) and ZnO was determined by XRD and Mossbauer spectroscopy. The yield of ZnO was 26-29%, which shows that the ratio of the competition-reaction (Zn/H2O system) has less effects on the total H-2 yield. The stoichiometry and the reaction mechanism of the system are discussed upon the analyses for the solid product. (C) 2001 International Association for Hydrogen Energy. Published by Elsevier Science Ltd. All rights reserved.

    DOI: 10.1016/S0360-3199(01)00039-8

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  • Enhancement of Op-releasing step with Fe2O3 in the water splitting by MnFe2O4-Na2CO3 system 査読

    H Kaneko, Y Hosokawa, N Gokon, N Kojima, N Hasegawa, M Kitamura, Y Tamaura

    JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS   62 ( 7 )   1341 - 1347   2001年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    In the O-2-releasing step of water splitting system, MnFe2O4 was completely regenerated from Na(Mn1/3Fe2/3)O2+delta by enhancement of O-2-releasing step with Fe2O3 at 1273 K. Thermodynamic data for the enhancement of the O-2-releasing step with alpha -Fe2O3 in the water splitting with the MnFe2O3-Na2CO3 system are experimentally confirmed. The amount of released oxygen attained to the theoretical value at around 1273 K (Po-2 = 10(-6)) and about 1240 K (Po-2 = 10(-7)). At higher temperature above 1273 K (Po-2 = 10(-6)) and 1240 K (Po-2 = 10(-7)), the released oxygen amount increased. In the three-step water splitting system with MnFe2O3-Na2CO3-Fe2O3, we proposed that there are some advantages required for application to the solar thermochemical process. (C) 2001 Elsevier Science Ltd. All rights reserved.

    DOI: 10.1016/S0022-3697(01)00034-8

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  • Solar Hydrogen Generation with H2O/ZnO/MnFe2O4 System 査読

    M. Inoue, R. Uehara, N. Hasegawa, N. Gokon, H. Kaneko, Y. Tamaura

    International Solar Energy Society 2001 Solar World Congress, Adelaide, Australia, November 25-30, 2001.   2001年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • Oxygen uptake and release mechanism of lithium manganese ferrite in the low temperature range of 573-773 K 査読

    T Sano, M Tsuji, N Gokon, H Kaneko, Y Tamaura

    JOURNAL OF THE AMERICAN CERAMIC SOCIETY   83 ( 10 )   2509 - 2514   2000年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER CERAMIC SOC  

    Oxygen uptake and release of (Li,Mn) ferrite [LMF; (Li0.60Mn1.20Fe1.20)(1-delta)O-4; delta = 0.007 to 0.033] was investigated concerning the relations between redox reactions of ferrite and cation migration. Mossbauer spectroscopy and X-ray diffractometry showed that some of the Li+ and Fe3+ ions migrated from the A sites to the B sites of the spinel-type structure and Mn4+ ions migrated from the B sites to the A sites during oxygen uptake at 573 K. The cation-deficient LMF formed by the oxygen uptake released oxygen molecules in He gas only at 660 K. The cation migration during the oxygen release was in the opposite direction of the movement during oxygen uptake at 573 K.

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  • Growth behavior of fine grains formed by diffusion induced recrystallization in the Cu(Zn) system 査読

    N Goukon, T Ikeda, M Kajihara

    ACTA MATERIALIA   48 ( 11 )   2959 - 2968   2000年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The growth behavior of fine grains produced due to diffusion induced recrystallization (DIR) was experimentally studied for the Cu(Zn) system using single crystal Cu specimens. The Cu specimens were annealed at 693 K for various times together with st Zn source alloy by a capsule zincification technique and then DIR was observed to take place on the surfaces of the specimens. The DIR region consists of an almost single layer of fine grains. Although the average height I and the average diameter s of the fine grains increase with increasing annealing time, the aspect ratio s/l is kept to be nearly unity during annealing. The Zn concentration on the specimen surface is smaller than that in the Zn source alloy at early stages of the reaction. Such lower Zn concentrations could be explained using the maximum driving force model proposed by Kajihara and Gust (Acta metall. mater., 1991, 39, 2565). The composition on the specimen surface gradually approaches the equilibrium value with increasing annealing time. This means that the amount of the Zn source alloy is large enough to maintain the supply of Zn atoms to the specimen in each zincification capsule. The kinetic model by Li and Hillert (Acta metall., 1981, 29, 1949) and the extended model by Kawanami ct al. (ISIJ int., 1997, 37, 921) could rather well reproduce the annealing time dependence of the growth rate of the DIR region. The contribution of volume diffusion to the transfer of Zn atoms from the surface to the moving boundaries in the DIR region was estimated to be negligible. Thus, the chemical driving force is considered to be the most important driving force for the grain boundary migration and the boundary diffusion along the grain boundaries in the DIR region is recognized to be the rate controlling process of DIR. (C) 2000 Acta Metallurgica Inc. Published by Elsevier Science Lid. AII rights reserved.

    DOI: 10.1016/S1359-6454(00)00096-3

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  • Boundary energies of Sigma 11 [110] asymmetric tilt boundaries in Cu determined from the shape of boundary silica particles 査読

    N Goukon, T Yamada, M Kajihara

    ACTA MATERIALIA   48 ( 11 )   2837 - 2842   2000年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The boundary energies of Sigma 11 [110] asymmetric tilt boundaries with a misorientation angle of theta = 50.5 degrees in Cu have been experimentally determined by a silica particle observation method for various inclination angles between phi = 0 and 90 degrees. This method has no drawbacks that are inevitable in boundary grooving and tri-junction methods. In the boundary energy vs inclination angle diagram, three deep cusps exist at phi = 10, 64.8 and 90 degrees whereas a shallow cusp appears at phi = 35.3 degrees. Such inclination angle dependence of the boundary energy has been utilized to analyze the faceting of the boundary. The observations on the faceting reported for Sigma 11 [110] tilt boundaries in face-centered cubic (f.c.c.) metals have been quantitatively accounted for by the present analysis. (C) 2000 Acta Metallurgica inc. Published by Elsevier Science Ltd. All rights reserved.

    DOI: 10.1016/S1359-6454(00)00103-8

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  • Characteristic features of diffusion induced grain boundary migration for Sigma 9 [110] asymmetric tilt boundaries in the Cu(Zn) system 査読

    N Goukon, T Ikeda, M Kajihara

    ACTA MATERIALIA   48 ( 7 )   1551 - 1562   2000年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The characteristic features of diffusion induced grain boundary migration (DIGM) in the Cu(Zn) system were experimentally studied for [110] asymmetric tilt boundaries using Cu bicrystals annealed at 693 K for various times by a capsule zincification technique. The experiment was carried out for the boundaries with inclination angles of phi = 0, 20, 35, 55, 65 and 90 degrees and with a constant misorientation angle of theta = 39 degrees (Sigma 9). During annealing, the grain boundary migrates towards a crystal grain of larger coherency strain energy with higher probability due to DIGM. Taking elastic anisotropy of each crystal grain into consideration, the difference between the probabilities of grain boundary migration towards both side grains can be accounted for by the coherency strain model proposed by Hillert. The migration rate v of the moving boundary is almost constant regardless of the annealing time t between t = 72 and 384 h (2.59 x 10(5) and 1.38 x 10(6) s). The value of v monotonically decreases with increasing inclination angle. This implies that the boundary diffusion coefficient of Zn in Cu is a monotone decreasing function of the inclination angle. The experimental results on the kinetics at the steady state stage were theoretically analyzed using the energy balance model proposed by Kajihara and Gust (Scripta mater., 1998, 38, 1621. The analysis indicates that the effective driving force Delta(ef)G for the grain boundary migration is merely one-thirtieth of the chemical driving force, whereas it still remains three times greater than the minimum value corresponding to the coherency strain energy during DIGM under the present, experimental conditions. The mobility of the moving boundary was evaluated to be M = 3.77 x 10(-17) m(4)/Js from the values of v and Delta(ef)G according to the relationship M = v/Delta(ef)G. This value of M is close to the results estimated by Yamamoto et al, (Acta mater., 1999, 47, 1757) for the [100] twist and random boundaries in the Cu(Zn) system. (C) 2000 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved.

    DOI: 10.1016/S1359-6454(99)00424-3

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  • Cu双結晶における[110]ねじれ粒界および傾角粒界の材料組織学的性質 査読

    郷右近展之

    東京工業大学   2000年

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    記述言語:日本語   掲載種別:学位論文(博士)  

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  • Solar H2 Production by Two Step Water Splitting with Zn-Ferrite-Fe3O4 System 査読

    Y. TAMAURA, N. HASEGAWA, N. KOJIMA, N.GOKON, H. KANEKO

    International Conference on Ferrite, Kyoto, September 18-21, 2000.   2000年

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  • Methane Reforming with CO2 in Molten Salt Using FeO Catalyst 査読

    N. GOKON, Y. OKU, H. KANEKO, Y. TAMAURA

    International Conference on Ferrite, Kyoto, September 18-21, 2000.   2000年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • H2 Generation by H2O/Zn/Fe3O4 Reaction System 査読

    N. KOJIMA, N. HASEGAWA, R. UEHARA, N. GOKON, H. KANEKO, Y. TAMAURA

    International Conference on Ferrite, Kyoto, September 18-21, 2000.   2000年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

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  • マテリアルステージ

    郷右近 展之( 担当: 分担執筆 ,  範囲: マテリアルニュース&トピックス,次世代太陽熱発電への適用を目指した金属系材料 による高温潜熱蓄熱とその可能性)

    株式会社 技術情報協会  2024年5月 

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  • 次世代太陽熱発電のための金属系蓄熱材料と潜熱蓄熱システム

    郷右近 展之( 担当: 分担執筆 ,  範囲: 【第IV編 応用】第3章)

    (株)シーエムシー出版  2024年4月  ( ISBN:9784781317991

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    記述言語:日本語

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  • CO2の有効利用技術の開発 ~有用化学品製造、燃料製造、直接利用、固定化、資源化~

    郷右近 展之( 担当: 分担執筆 ,  範囲: 第6章 CO2を利用した燃料の製造技術と取組み; 第3節 高温太陽熱を熱源として駆動する二段階熱化学サイクルによる二酸化炭素の燃料化技術)

    技術情報協会  2023年7月  ( ISBN:9784861049729

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  • 再生可能エネルギーの開発と市場

    郷右近展之( 担当: 分担執筆 ,  範囲: 第5章 次世代太陽熱発電のための金属系潜熱蓄熱材料と蓄熱システムの開発)

    シーエムシー出版  2023年1月  ( ISBN:9784781317236

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  • カーボンニュートラルに向けた水素製造・P2Gと関連技術の最新動向

    郷右近 展之( 担当: 分担執筆 ,  範囲: 第6章 高温太陽集光システムによるソーラー水素・炭化水素燃料製造の研究動向)

    (株)シーエムシー・リサーチ  2022年12月 

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  • 二酸化炭素有効利用技術 ~DAC から物質合成、産業利用まで~

    郷右近 展之( 担当: 分担執筆 ,  範囲: 第 3 編 二酸化炭素の産業への有効利用、第4章 燃料開発、 第 1 節 高温太陽熱を熱源とする二段階熱化学プロセスによる ソーラー液体燃料製造)

    株式会社エヌ・ティー・エス  2022年5月  ( ISBN:9784860437862

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  • 熱エネルギーの有効活用に向けた蓄熱技術開発

    郷右近 展之( 担当: 分担執筆 ,  範囲: 次世代太陽熱発電のための金属系潜熱蓄熱材料と蓄熱システムの開発)

    シーエムシー出版  2022年4月  ( ISBN:9784781316659

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  • アンモニアを用いた水素エネルギーシステム

    児玉 竜也, 郷右近展之( 担当: 分担執筆 ,  範囲: 第3章 高温熱化学水素製造)

    シーエムシー出版  2015年6月  ( ISBN:9784781310732

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    総ページ数:vi, 239p  

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  • 水素エネルギーの開発と応用

    郷右近 展之, 児玉 竜也( 担当: 分担執筆 ,  範囲: 第10章 二段階水熱分解ソーラー水素製造システムの開発)

    シーエムシー出版  2014年8月  ( ISBN:9784781309750

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    総ページ数:vii, 218p   記述言語:日本語

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  • 水素利用技術集成 vol.4 高効率貯蔵技術、水素社会構築を目指して

    岡野一清, 井関孝弥, 阿部竜, 児玉竜也, 郷右近展之, 中村優美子, 伊藤直次, 市川貴之, 高野俊夫, Eコンテイナー, 池田哲史, 利用技術研究組, 秋葉悦男, 笠井秀明, ほ

    エヌ・ティー・エス  2014年4月  ( ISBN:4864690820

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    総ページ数:354  

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  • 太陽熱発電・燃料化技術―太陽熱から電力・燃料をつくる (-)

    吉田 一雄, 郷右近 展之, 児玉 竜也, 日本エネルギー学会( 担当: 共著)

    コロナ社  2012年7月  ( ISBN:4339068306

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    総ページ数:174  

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  • 医療用マテリアルと機能膜

    西尾広介, 池田森人, 成松宏樹, 壺内信吾, 郷右近展之, 半田宏( 担当: 分担執筆 ,  範囲: 第7章 磁性ビーズ開発と医療への展開)

    シーエムシー出版  2005年5月 

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  • ナノ粒子・マイクロ粒子の最先端技術

    壷内信吾, 西尾広介, 池田森人, 成松宏樹, 郷右近展之, 半田 宏( 担当: 分担執筆 ,  範囲: 4.創薬に向けた磁気アフェニティビーズの創製)

    シーエムシー出版  2004年10月 

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MISC

  • 熱蓄積 招待

    郷右近 展之

    2023年度光技術動向調査報告書   2024年6月

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    担当区分:筆頭著者, 最終著者, 責任著者   記述言語:日本語   掲載種別:機関テクニカルレポート,技術報告書,プレプリント等  

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  • 図解でわかる再生可能エネルギー×電力システム ~脱炭素を実現するクリーンな電力需給技術~ 招待

    一般財団法人, エネルギー総合工学研究所

    日本エネルギー学会機関誌 えねるみくす   2023年9月

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    担当区分:筆頭著者, 最終著者, 責任著者   記述言語:日本語   掲載種別:書評論文,書評,文献紹介等  

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  • 熱蓄積 招待

    郷右近 展之

    2022年度光技術動向調査報告書   2023年6月

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    担当区分:筆頭著者, 最終著者, 責任著者   記述言語:日本語   掲載種別:機関テクニカルレポート,技術報告書,プレプリント等  

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  • 次世代太陽熱発電・蓄熱発電のための高温潜熱・化学蓄熱材料 招待

    郷右近 展之

    季報 エネルギー総合工学   45 ( 3 )   34 - 46   2022年10月

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    担当区分:筆頭著者, 最終著者, 責任著者   記述言語:日本語   掲載種別:記事・総説・解説・論説等(学術雑誌)  

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  • 新エネルギーキャリアの今後の展望: 次世代太陽熱発電に関わる高温集熱・蓄熱・熱供給システムの研究開発動向と将来展望 招待 査読

    郷右近 展之

    非破壊検査   71 ( 9 )   398 - 03   2022年9月

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    担当区分:筆頭著者, 最終著者   記述言語:日本語   掲載種別:記事・総説・解説・論説等(学術雑誌)  

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  • 次世代太陽熱発電・蓄熱発電のための金属系材料による高温潜熱蓄熱 招待

    郷右近 展之

    化学工業   73 ( 9 )   582 - 589   2022年9月

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    担当区分:筆頭著者, 最終著者, 責任著者   記述言語:日本語   掲載種別:記事・総説・解説・論説等(学術雑誌)  

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  • 蓄熱システム実証試験の最前線 招待

    郷右近 展之

    日本エネルギー学会機関誌 えねるみくす   101 ( 6 )   688   2022年6月

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    記述言語:日本語   掲載種別:記事・総説・解説・論説等(学術雑誌)  

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  • 講座:水素エネルギー利用技術 水素製造技術(熱化学水素製造) 招待

    郷右近 展之

    日本エネルギー学会機関誌 えねるみくす   101 ( 2 )   215 - 218   2022年3月

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    担当区分:筆頭著者, 最終著者, 責任著者   記述言語:日本語   掲載種別:記事・総説・解説・論説等(学術雑誌)  

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  • 次世代太陽熱発電における化学蓄熱の研究動向と将来展望 ─金属酸化物による高温利用の化学蓄熱─ 招待 査読

    郷右近 展之

    セラミックス   56 ( 12 )   813 - 816   2021年12月

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    担当区分:筆頭著者, 最終著者, 責任著者   記述言語:日本語   掲載種別:記事・総説・解説・論説等(学術雑誌)  

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  • 熱蓄積 招待

    郷右近 展之

    2021年度光技術動向調査報告書   2021年6月

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    担当区分:筆頭著者, 最終著者, 責任著者   記述言語:日本語   掲載種別:機関テクニカルレポート,技術報告書,プレプリント等  

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  • 蓄エネルギー技術最前線 招待

    郷右近 展之

    日本エネルギー学会機関紙 えねるみくす   100   216   2021年2月

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    担当区分:筆頭著者, 最終著者, 責任著者   記述言語:日本語   掲載種別:記事・総説・解説・論説等(その他)  

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  • 高温太陽熱利用のための定常流型粒子集熱器に関する研究

    SUZUKI Yudai, MATSUBARA Koji, KODAMA Tatsuya, SAKURAI Atsushi, BELLAN Selvan, GOKON Nobuyuki, MATSUDAIRA Yusaku

    Proceedings. International Conference on Flow Dynamics (CD-ROM)   15th   2018年

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  • 高温太陽集熱の化学燃料転換に関する研究の現状と将来展望 (Special articles : Leading-edge Technology for Energy Conversion of Solar Thermal Energy into Chemical Fuels)

    郷右近 展之, 児玉 竜也

    Journal of the Japan Institute of Energy = 日本エネルギー学会誌   94 ( 3 )   212 - 217   2015年3月

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    記述言語:日本語   出版者・発行元:一般社団法人日本エネルギー学会  

    The current technologies for solar chemical fuel productions using concentrated solar radiation as an energy source and carbonaceous resources as a chemical source such as coal cokes and natural gas were mainly reviewed in this paper. These energy conversion technologies enable productions of long term storable clean energy carrier from solar energy and solar energy transportation from sunbelt to remote countries, such as Japan. Concentrated solar radiation has some specific properties such as high density, heterogeneous distribution of thermal flux, and frequent thermal transients due to the fluctuating insolation. Thus, some solarspecific reactors/reformers have been developed to convert the high temperature solar heat into hydrogen and synthetic gas of carbon monoxide and hydrogen via solar thermochemical processes of water-splitting, natural gas reforming and coal gasification. In this paper, research activities in Niigata University are mainly introduced in this paper.

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  • 太陽集熱によるソーラー水熱分解サイクル (特集 再生可能エネルギーからの水素製造)

    児玉 竜也, 郷右近 展之, 松原 幸治

    Journal of the Japan Institute of Energy = 日本エネルギー学会誌   94 ( 1 )   35 - 41   2015年1月

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    記述言語:日本語   出版者・発行元:一般社団法人日本エネルギー学会  

    Solar thermochemical water-splitting cycles have been developed to convert concentrating solar radiation or heat to hydrogen in world sun-belt regions with abundant insolation. Hybrid sulfur cycle and metal-oxide cycles have been mostly investigated for solar thermochemical water splitting because these cycles can be operated only by two steps. In order to perform these cycles, solar concentrating system, active catalysts, metal oxides, and solar reactors have been developed since these cycles require temperatures around 1000 - 1500℃. Several concepts of solar reactor systems has been demonstrated by solar furnace, solar tower, etc., and in the demonstrations, solar power input is about 10 - 100 kW_<th>. Niigata University is developing two types of solar reactors, the foam device reactor type and the fluidized beds reactor type, and the two reactor concepts have been up-scaled and tested on solar.

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  • 高温太陽集熱による化学燃料製造技術

    郷右近 展之, 児玉 竜也

    日本エネルギー学会誌 = Journal of the Japan Institute of Energy   90 ( 4 )   339 - 350   2011年4月

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    記述言語:日本語   出版者・発行元:一般社団法人日本エネルギー学会  

    This paper reviews the recent technology for solar fuel production using concentrated solar high temperature heat as an energy source and water and fossil fuels as a chemical source. This technology enables production of long term storable clean energy carrier from solar energy and solar energy transportation from sunbelt to remote countries, such as Japan. Concentrated solar radiation has some specific properties such as high density, heterogeneous distribution of thermal flux, and frequent thermal transients due to the fluctuating insolation. Thus, some solar-specific reactors/reformers have been developed to convert the high temperature solar heat into hydrogen and synthetic gas of carbon monoxide and hydrogen via solar thermochemical processes of thermochemical water-splitting, natural gas reforming and coal gasification. The technical development and feasibility of these solar fuel production processes is discussed, and recent international collaboration researches for demonstration of solar fuel production are introduced here.

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  • 高温太陽集熱によるソーラー水素製造技術

    児玉 竜也, 郷右近 展之

    季報エネルギー総合工学   34 ( 1 )   18 - 30   2011年4月

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    記述言語:日本語   出版者・発行元:エネルギー総合工学研究所  

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  • 高温太陽集熱による水熱分解水素制造

    児玉 竜也, 郷右近 展之

    化学工学 = Chemical engineering   75 ( 1 )   26 - 29   2011年1月

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    記述言語:日本語   出版者・発行元:化学工学会  

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  • 高温太陽熱を利用したソーラー水素の製造

    児玉 竜也, 郷右近 展之

    太陽エネルギー = Solar energy   35 ( 5 )   3 - 13   2009年9月

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    記述言語:日本語   出版者・発行元:日本太陽エネルギー学会  

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  • Local structure of sulfur in organic molecules immobilized on ferrite nanoparticles

    Nobuyuki Gokon, Kosuke Nishio, Morihito Ikeda, Hiroki Narimatsu, Yasuo Izumi, Hiroshi Handa

    Photon Factory Activity Report 2003   21B   224 - 224   2004年

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    記述言語:英語   掲載種別:速報,短報,研究ノート等(大学,研究機関紀要)  

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  • 湿式フェライト生成反応における強磁場印加効果

    郷右近 展之, 長谷川 紀子, 金子 宏, 玉浦 裕, 伊藤 喜久男, 小原 健司

    物質・材料研究機構 強磁場研究センター 2001年度 年次報告書   120 - 121   2002年

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    担当区分:筆頭著者, 最終著者, 責任著者   記述言語:日本語   掲載種別:機関テクニカルレポート,技術報告書,プレプリント等  

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  • a-およびg-FeOOHを用いた水溶液マグネタイト合成における強磁場印加効果

    郷右近 展之, 長谷川 紀子, 金子 宏, 玉浦 裕, 小原 健司

    第3回磁気分離研究開発に関するワークショップ-環境改善と資源循環利用-   96 - 98   2002年

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    担当区分:筆頭著者, 最終著者, 責任著者   記述言語:日本語   掲載種別:講演資料等(セミナー,チュートリアル,講習,講義他)  

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  • 強磁場におけるFe2+/Fe3+懸濁溶液を用いたマグネタイトの結晶成長速度

    郷右近 展之, 島田 綾乃, 玉浦 裕, 伊藤 喜久男, 小原 健司

    物質・材料研究機構 強磁場ステーション2000年度 年次報告書   131 - 132   2001年

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    担当区分:筆頭著者, 最終著者, 責任著者   記述言語:日本語   掲載種別:機関テクニカルレポート,技術報告書,プレプリント等  

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  • フェリ磁性体を用いた環境水中のリン及び重金属イオンの磁気分離

    郷右近 展之, 島田 綾乃, 長谷川 紀子, 金子 宏, 玉浦 裕, 伊藤 喜久男, 小原 健司

    第2回磁気分離研究開発に関するワークショップ-環境改善と資源循環利用-   46 - 48   2001年

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    担当区分:筆頭著者, 最終著者, 責任著者   記述言語:日本語   掲載種別:講演資料等(セミナー,チュートリアル,講習,講義他)  

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  • フェリ磁性を用いた環境水中のリン酸イオンの磁気分離

    郷右近 展之, 島田 綾乃, 松岡 孝仁, 玉浦 裕, 伊藤 喜久男, 小原 健司

    科学技術庁 金属材料技術研究所 強磁場ステーション1999年度 年次報告書   148 - 149   2000年

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    担当区分:筆頭著者, 最終著者, 責任著者   記述言語:日本語   掲載種別:機関テクニカルレポート,技術報告書,プレプリント等  

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講演・口頭発表等

  • 太陽熱発電の研究動向と今後の展望について 招待

    郷右近 展之

    第32回日本エネルギー学会大会  2023年8月 

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    開催年月日: 2023年8月

    記述言語:日本語   会議種別:口頭発表(基調)  

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  • 次世代太陽熱発電と蓄熱発電を目的とした金属系材料による600℃以上の高温潜熱蓄熱 招待

    郷右近 展之

    第6回大学発シーズ マッチングセミナー  2022年4月 

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    開催年月日: 2022年4月

    記述言語:日本語   会議種別:公開講演,セミナー,チュートリアル,講習,講義等  

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  • SolarPACES2020報告 -Gen3 CSP liquid pathway projectについて― 招待

    郷右近 展之

    太陽熱・蓄熱技術研究会  2021年3月 

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    開催年月日: 2021年

    記述言語:日本語   会議種別:公開講演,セミナー,チュートリアル,講習,講義等  

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  • 次世代太陽熱発電における高温蓄熱材料・システム 招待

    郷右近 展之

    RE2024 第18回再生可能エネルギー世界展示会&フォーラム 分科会3  2024年1月 

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    記述言語:日本語   会議種別:公開講演,セミナー,チュートリアル,講習,講義等  

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  • 次世代太陽熱発電おける蓄熱材料と蓄熱システムについて 招待

    郷右近 展之

    日本伝熱学会北陸信越支部 秋季セミナー  2023年11月 

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    記述言語:日本語   会議種別:公開講演,セミナー,チュートリアル,講習,講義等  

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  • 次世代太陽熱発電における蓄熱システムの研究動向 招待

    郷右近 展之

    ㈱技術情報センター セミナー 蓄熱発電の動向と要素技術開発(大規模、太陽熱利用、バイオマス発電との統合など)  2023年10月 

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    記述言語:日本語   会議種別:公開講演,セミナー,チュートリアル,講習,講義等  

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  • 再生可能エネルギーと蓄エネルギー技術 招待

    郷右近 展之

    新潟大学 工学部 出前講義  2023年10月 

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    記述言語:日本語   会議種別:公開講演,セミナー,チュートリアル,講習,講義等  

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  • 次世代太陽熱発電にお ける化学の役割 招待

    郷右近 展之

    2023 年度「化学への招待〜高校生のための化学講座」新潟地区講演会  2023年8月 

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    記述言語:日本語   会議種別:公開講演,セミナー,チュートリアル,講習,講義等  

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  • 点集光関連技術 -SolarPACES2022における研究動向- 招待

    郷右近 展之

    太陽熱・蓄熱技術研究会  2023年3月 

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    記述言語:日本語   会議種別:公開講演,セミナー,チュートリアル,講習,講義等  

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  • 化学蓄熱関連技術 -SolarPACES2022における研究動向- 招待

    郷右近 展之

    太陽熱・蓄熱技術研究会  2023年2月 

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    記述言語:日本語   会議種別:公開講演,セミナー,チュートリアル,講習,講義等  

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  • 高温太陽熱を熱源とした熱化学プロセスによる水素製造 招待

    郷右近 展之

    第94回 EST-2委員会  2022年5月 

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    記述言語:日本語   会議種別:公開講演,セミナー,チュートリアル,講習,講義等  

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  • 太陽熱発電における点集光関連技術 -SolarPACES2021における研究動向- 招待

    郷右近 展之

    太陽熱・蓄熱技術研究会  2022年3月 

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    記述言語:日本語   会議種別:公開講演,セミナー,チュートリアル,講習,講義等  

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  • 太陽熱や変動再エネの蓄エネルギーを目的とした金属系材料を使用した高温潜熱蓄熱 招待

    郷右近 展之

    R3年度 JST_新技術説明会  2021年12月 

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    記述言語:日本語   会議種別:口頭発表(招待・特別)  

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  • 次世代太陽熱発電の最新研究動向と熱化学プロセスによる太陽熱水素製造・二酸化炭素循環利用技術 招待

    郷右近 展之

    蓄熱発電と高温蓄熱・太陽熱利用の技術開発動向((株)技術情報センター)  2021年10月 

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    記述言語:日本語   会議種別:公開講演,セミナー,チュートリアル,講習,講義等  

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  • 次世代太陽熱発電にむけた高温潜熱蓄熱技術 招待

    郷右近 展之

    新潟大学研究シーズプレゼンテーション  2021年9月 

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    記述言語:日本語   会議種別:シンポジウム・ワークショップ パネル(指名)  

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  • SolarPACES2020国際会議報告-化学蓄熱を含む固体粒子蓄熱の研究動向― 招待

    郷右近 展之

    太陽熱・蓄熱技術研究会  2021年9月 

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    記述言語:日本語   会議種別:公開講演,セミナー,チュートリアル,講習,講義等  

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  • 地球環境時代における再生可能エネルギー利用と水素社会の意義と今後の研究開発について 招待

    郷右近 展之

    (一社)新潟県電子機械工業会 記念講演会  2021年5月 

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    記述言語:日本語   会議種別:公開講演,セミナー,チュートリアル,講習,講義等  

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  • 潜熱蓄熱・化学蓄熱関連研究-SolarPACES2019国際会議- 招待

    郷右近 展之

    集光型太陽熱技術研究会  2020年7月 

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    記述言語:日本語   会議種別:口頭発表(招待・特別)  

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  • 熱媒体関連研究の概要-SolarPACES2019における研究動向- 招待

    郷右近 展之

    集光型太陽熱技術研究会  2020年2月 

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    記述言語:日本語   会議種別:口頭発表(招待・特別)  

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  • 潜熱・化学蓄熱関連研究の概要-SolarPACES2018における研究動向- 招待

    郷右近 展之

    集光型太陽熱技術研究会  2019年1月 

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    記述言語:日本語   会議種別:口頭発表(招待・特別)  

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  • 太陽集熱の水素エネルギー変換プロセス 招待

    郷右近 展之

    一般社団法人水素エネルギー協会(HESS)「第157回定例研究会」  2018年11月 

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    記述言語:日本語   会議種別:口頭発表(招待・特別)  

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  • EXPERIMENTAL AND NUMERICAL SIMULATION OF MELTING PROCESS OF PHASE CHANGE MATERIAL FOR LATENT HEAT STORAGE SYSTEM DESIGN IN CONCENTRATED SOLAR POWEREXPERIMENTAL AND NUMERICAL SIMULATION OF MELTING PROCESS OF PHASE CHANGE MATERIAL FOR LATENT HEAT STORAGE S 招待 国際会議

    郷右近 展之

    3rd Japanese-German Workshop on Renewable Energies  2018年10月 

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    記述言語:英語   会議種別:口頭発表(招待・特別)  

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  • 太陽熱発電における化学蓄熱研究の概説-SolarPACES2014-2017における研究動向を中心に- 招待

    郷右近 展之

    集光型太陽熱技術研究会  2018年9月 

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    記述言語:日本語   会議種別:口頭発表(招待・特別)  

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  • 潜熱・化学蓄熱関連研究の概要-SolarPACES2014-2016における研究動向- 招待

    郷右近 展之

    内閣府・戦略的イノベーション創造プログラム(SIP)における高温集熱グループ研究会  2017年6月 

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    記述言語:日本語   会議種別:口頭発表(招待・特別)  

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  • 潜熱・化学蓄熱関連研究の概要-SolarPACES2017における研究動向- 招待

    郷右近 展之

    集光型太陽熱技術研究会  2017年 

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    記述言語:日本語   会議種別:公開講演,セミナー,チュートリアル,講習,講義等  

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  • 潜熱・化学蓄熱関連研究の概要-SolarPACES2016における研究動向- 招待

    郷右近 展之

    集光型太陽熱技術研究会  2016年 

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    記述言語:日本語   会議種別:公開講演,セミナー,チュートリアル,講習,講義等  

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  • R&D ACTIVITIES on CSP and solar chemistry in Japan 招待 国際会議

    郷右近 展之

    International Green Energy Business Conference  2015年4月 

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    記述言語:英語   会議種別:口頭発表(招待・特別)  

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  • 潜熱・化学蓄熱関連研究の概要-SolarPACES2015における研究動向- 招待

    郷右近 展之

    集光型太陽熱技術研究会  2015年 

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    記述言語:日本語   会議種別:公開講演,セミナー,チュートリアル,講習,講義等  

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  • 潜熱・化学蓄熱関連研究の概要-SolarPACES2014における研究動向- 招待

    郷右近 展之

    集光型太陽熱技術研究会  2014年 

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    記述言語:日本語   会議種別:公開講演,セミナー,チュートリアル,講習,講義等  

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産業財産権

  • 蓄熱材料および蓄熱発電装置

    郷右近 展之

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    出願番号:特願2020-38149  出願日:2020年3月

    特許番号/登録番号:特許第7408888号 

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  • 水素の製造方法、一酸化炭素の製造方法および反応媒体

    伊藤 直樹, 郷右近 展之

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    出願番号:特願2020-014747  出願日:2020年1月

    特許番号/登録番号:特許第7417224号 

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  • 集光太陽光の受熱装置、反応装置及び加熱装置

    兒玉 竜也, 松原 幸治, 郷右近 展之

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    出願人:国立大学法人 新潟大学

    出願番号:JP2015062332  出願日:2015年4月

    公開番号:WO2015-174236  公開日:2015年11月

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  • 内循環流動層を用いた石炭コークスのガス化装置及びガス化法

    兒玉 竜也, 郷右近 展之, 松原 幸治, 櫻井 篤

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    出願人:国立大学法人 新潟大学

    出願番号:特願2013-222867  出願日:2013年10月

    公開番号:特開2015-086232  公開日:2015年5月

    特許番号/登録番号:特許第6232923号  発行日:2017年11月

    J-GLOBAL

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  • 内循環流動層を用いた石炭コークスのガス化装置及びガス化法

    兒玉 竜也, 郷右近 展之, 松原 幸治, 櫻井 篤

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    出願人:国立大学法人 新潟大学

    出願番号:特願2013-222867  出願日:2013年10月

    公開番号:特開2015-086232  公開日:2015年5月

    J-GLOBAL

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  • 太陽光を利用した集熱蓄熱装置

    児玉 竜也, 郷右近 展之, 松原 幸治, 櫻井 篤

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    出願人:国立大学法人 新潟大学

    出願番号:特願2014-534366  出願日:2013年9月

    特許番号/登録番号:特許第6165743号  発行日:2017年6月

    J-GLOBAL

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  • 太陽光を利用した集熱蓄熱装置

    児玉 竜也, 郷右近 展之, 松原 幸治, 櫻井 篤

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    出願人:国立大学法人 新潟大学

    出願番号:JP2013073693  出願日:2013年9月

    公開番号:WO2014-038553  公開日:2014年3月

    J-GLOBAL

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  • 内循環流動層を用いた水熱分解装置及び水熱分解法

    児玉 竜也, 郷右近 展之, 櫻井 篤, 松原 幸治

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    出願人:国立大学法人 新潟大学

    出願番号:特願2013-556494  出願日:2013年1月

    特許番号/登録番号:特許第5986589号  発行日:2016年8月

    J-GLOBAL

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  • 内循環流動層を用いた水熱分解装置及び水熱分解法

    児玉 竜也, 郷右近 展之, 櫻井 篤, 松原 幸治

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    出願人:国立大学法人 新潟大学

    出願番号:JP2013052211  出願日:2013年1月

    公開番号:WO2013-115316  公開日:2013年8月

    J-GLOBAL

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  • 水熱分解による水素製造法及び水素製造装置

    児玉 竜也, 郷右近 展之

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    出願人:国立大学法人 新潟大学

    出願番号:特願2011-544265  出願日:2010年12月

    特許番号/登録番号:特許第5739818号  発行日:2015年5月

    J-GLOBAL

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  • 水熱分解による水素製造法及び水素製造装置

    児玉 竜也, 郷右近 展之

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    出願人:国立大学法人 新潟大学

    出願番号:JP2010071485  出願日:2010年12月

    公開番号:WO2011-068122  公開日:2011年6月

    J-GLOBAL

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  • 有機物質とフェライト粒子とを有する複合粒子及びその製造方法

    半田 宏, 阿部 正紀, 郷右近 展之, 西尾 広介

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    出願人:国立大学法人東京工業大学

    出願番号:特願2005-261823  出願日:2005年9月

    公開番号:特開2007-070195  公開日:2007年3月

    J-GLOBAL

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  • マグネタイト微粒子の製造方法

    半田 宏, 阿部 正紀, 郷右近 展之, 池田 森人, 西尾 広介

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    出願人:国立大学法人東京工業大学

    出願番号:特願2005-035257  出願日:2005年2月

    公開番号:特開2006-219353  公開日:2006年8月

    特許番号/登録番号:特許第4621911号 

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  • ポリマー被覆微粒子の製造方法及びポリマー被覆微粒子

    半田 宏, 阿部 正紀, 郷右近 展之, 壷内 信吾, 畠山 士, 西尾 広介, 池田 森人, 成松 宏樹

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    出願番号:特願2004-363638  出願日:2004年12月

    公開番号:特開2005-200643  公開日:2005年7月

    特願2003-417152号

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  • ポリマー被覆強磁性粒子の製造方法及びポリマー被覆強磁性粒子

    半田 宏, 西尾 広介, 郷右近 展之, 阿部 正紀

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    出願人:国立大学法人東京工業大学

    出願番号:特願2004-280679  出願日:2004年9月

    公開番号:特開2006-88131  公開日:2006年4月

    公表番号:WO2007110917A1 

    特許番号/登録番号:特許第5152884号  登録日:2012年12月  発行日:2013年2月

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  • 有機物質とフェライトとの複合材料とその製造方法

    半田 宏, 西尾 広介, 阿部 正紀, 郷右近 展之

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    出願人:財団法人理工学振興会

    出願番号:特願2004-226131  出願日:2004年8月

    公開番号:特開2005-060221  公開日:2005年3月

    特願2003-284352号

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受賞

  • 平成28年度 進歩賞(学術部門)

    2017年2月   日本エネルギー学会   「熱化学プロセスによる高温太陽集熱の化学燃料転換技術の開発」

    郷右近 展之

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  • 第6回インテリジェント・コスモス奨励賞

    2007年5月   「温暖化ガスを排出しない再生可能エネルギーの水素燃料への転換技術の構築」

    郷右近 展之

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  • 手島記念研究賞(博士論文賞)

    2001年3月   「Cu双結晶における[110]ねじれ粒界および傾角粒界の材料組織学的性質」

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    受賞国:日本国

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共同研究・競争的資金等の研究

  • 次世代太陽熱発電のための新型潜熱蓄熱システムの開発

    研究課題/領域番号:22H02016

    2022年4月 - 2025年3月

    制度名:科学研究費助成事業 基盤研究(B) (研究代表者)

    研究種目:基盤研究(B)

    提供機関:日本学術振興会

    郷右近 展之

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    担当区分:研究代表者 

    配分額:17420000円 ( 直接経費:13400000円 、 間接経費:4020000円 )

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  • 高温蓄熱による変動再エネ安定化および導入拡大に関する研究

    2021年4月 - 2023年3月

    提供機関:科学研究費助成事業 挑戦的研究(萌芽)(研究代表者)

    郷右近 展之

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    担当区分:研究代表者 

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  • 太陽熱発電のための潜熱利用型の高密度蓄熱システムの開発

    研究課題/領域番号:20K05398

    2020年4月 - 2023年3月

    制度名:科学研究費助成事業 基盤研究(C)(研究分担者)

    研究種目:基盤研究(C)

    提供機関:日本学術振興会

    籏町 剛

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    担当区分:研究分担者 

    配分額:4420000円 ( 直接経費:3400000円 、 間接経費:1020000円 )

    海外のサンベルト地域では大型太陽集光システムで得られる高温太陽集熱によるCO2フリーの太陽熱発電が実用化している。本研究では太陽熱発電の蓄熱温度に適合する蓄熱システム開発を行う。すなわち、固体/液体相変化材料を蓄熱体として採用した太陽熱発電のための融解凝固利用による潜熱利用型の高密度潜熱蓄熱システムの開発を目的としている。2021年度は(1)蓄熱材の蓄熱/放熱過程の熱サイクル試験(2)熱サイクル試験における放射伝熱プロセスの影響(3)自作のラボスケール潜熱蓄熱試験装置の試験運転を行った。また、(4)塩化物系溶融塩と蓄熱容器材料との高温腐食試験を行った。溶融塩腐食メカニズムを推定し、腐食を回避する手法について検討を行った。

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  • 高温太陽集熱による未利用炭素資源の流動層ソーラーガス化水素製造システムの開発

    2019年4月 - 2022年3月

    提供機関:科学研究費補助金 基盤研究(B)(研究代表者)

    郷右近 展之

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    担当区分:研究代表者  資金種別:競争的資金

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  • 太陽集熱による熱化学水素製造に関する研究

    2018年4月 - 2023年3月

    提供機関:JXTGエネルギー(現、ENEOS)株式会社

    郷右近 展之

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    担当区分:研究代表者 

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  • 次世代型蓄エネルギー技術実用化推進事業

    2018年4月 - 2019年3月

    提供機関:環境省委託事業(研究分担者)

    エネルギー総合工学研究所

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    資金種別:競争的資金

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  • 高熱伝導性蓄熱体を備えたソーラー天然ガス改質反応システムの開発

    2016年4月 - 2019年3月

    制度名:科学研究費補助金 基盤研究(C)(研究分担者)

    旗町 剛

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    資金種別:競争的資金

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  • 高温太陽集熱による流動層ガス化水素製造システムの開発

    2016年4月 - 2019年3月

    制度名:科学研究費補助金 基盤研究(B)(研究代表者)

    郷右近 展之

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    担当区分:研究代表者  資金種別:競争的資金

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  • ソーラー試験による太陽集熱水分解水素製造システムの開発

    研究課題/領域番号:26249151

    2014年4月 - 2017年3月

    制度名:科学研究費助成事業

    研究種目:基盤研究(A)

    提供機関:日本学術振興会

    児玉 竜也, 金子 宏, 松原 幸治, 清水 忠明, 郷右近 展之, 松葉 正, 横田 昌久, 吉田 一雄

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    配分額:40560000円 ( 直接経費:31200000円 、 間接経費:9360000円 )

    世界のサンベルト地域で太陽集熱によって水を分解して水素を製造する反応システムのプロトタイプの開発を目指し,金属酸化物(反応性セラミック)を媒体とする2段階水熱分解サイクルを用いた2つのタイプのソーラー反応器(円錐型発泡体デバイス式および粒子流動層式)の開発を行った.これらソーラー水熱分解反応器の原理で水素製造が可能であることを,30~40kWth反応器のソーラー試験で立証した.両反応器の実用化の設計概念を検討した結果,流動層式反応器は1サイクル当たりの水素製造能が大きいことかMWth級システムでの実用化に,発泡体式反応器は500kWth程度の小型システムでの実用化に適していることが見出された。

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  • ソーラー水素製造用の太陽熱/光分解性反応性セラミックの開発

    2014年4月 - 2016年3月

    制度名:科学研究費助成事業 挑戦的萌芽研究 (研究代表者)

    郷右近 展之

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    担当区分:研究代表者  資金種別:競争的資金

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  • 高温太陽集熱による新型ソーラーガス化反応器の開発

    2012年4月 - 2015年3月

    制度名:科学研究費補助金 基盤研究(B)(研究代表者)

    郷右近 展之

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    担当区分:研究代表者  資金種別:競争的資金

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  • ソーラー水素製造のためのプロトタイプ流動層反応器の開発

    研究課題/領域番号:22760689

    2010年4月 - 2012年3月

    制度名:科学研究費補助金 若手研究(B)(研究代表者)

    研究種目:若手研究(B)

    提供機関:日本学術振興会

    郷右近 展之

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    担当区分:研究代表者  資金種別:競争的資金

    反応性セラミックを反応媒体として用いる2段階水熱分解サイクルによる水素製造について、2段階反応により水を熱分解するプロトタイプ流動層反応器の開発を行った。この反応器は内部で酸素と水素を分離生成可能であり、二段階反応を一段階システム化することができる。5kW太陽炉シミュレーターによる照射試験により、本反応器による酸素と水素の同時生成・分離を実証した。この成果に基づき、この反応器システムによる水熱分解法及び装置に関して国内特許を出願した。

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  • 反応性セラミックによる水熱分解ソーラー反応器の開発

    研究課題/領域番号:21360478

    2009年 - 2011年

    制度名:科学研究費助成事業

    研究種目:基盤研究(B)

    提供機関:日本学術振興会

    児玉 竜也, 郷右近 展之

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    配分額:19110000円 ( 直接経費:14700000円 、 間接経費:4410000円 )

    本研究では,世界のサンベルト地域で得られる1000~1500℃の高温太陽集熱をエネルギー源として反応性セラミックによる二段階水熱分解サイクルによってソーラー水素の製造を行う2つの異なるコンセプトのソーラー反応器(発泡体デバイス型反応器および内循環流動層型反応器)のプロトタイプを3~5kWで作製し,これを太陽炉シミュレータあるいはパラボラディッシュ型太陽集光器(韓国インハ大学所有)を用いて性能評価することを目的とする。22年度は下記の研究成果が得られた。
    1)発泡体デバイス型反応器については下記の成果が得られた。
    発泡体デバイス反応器の2号器を作製し,新潟大の3kW太陽炉シミュレータによる擬似太陽集光による試験と,韓国インハ大学の5kWディッシュ型太陽集光器でのフィールド試験を並行して行った。反応体である発泡体でデバイスの反応性セラミック担持量等の合成条件を検討することにより,従来よりも発泡体デバイスの耐久性を向上させこの反応システムにおいて二段階水分解反応のサイクル化を行なうことが出来た。
    2)内循環流動層型反応器については下記の成果が得られた。
    内循環流動層反応器については,二段階サイクル反応を一段階プロセスとして実施できる従来にない画期的な反応器を考案している。,より安定に水素生成を行なうことを目的として反応器の設計改良を行い,これを新規に導入した5kW太陽炉シミュレータにより擬似太陽集光による性能試験を行った。同時に流動層に用いる反応性セラミック粒子の改良も行った結果,従来よりも一段階プロセスとして安定・定常的に水素生成を維持することに成功した。これに関しては国際特許出願を行なった。

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  • 高温太陽熱/水素転換のための内循環流動層反応器の開発

    2008年4月 - 2010年3月

    制度名:科学研究費補助金 若手研究(B)(研究代表者)

    郷右近 展之

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    担当区分:研究代表者  資金種別:競争的資金

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  • 低温水分解能を持つ熱-光ハイブリット活性セラミックデバイスの開発

    研究課題/領域番号:20656155

    2008年 - 2009年

    制度名:科学研究費助成事業

    研究種目:挑戦的萌芽研究

    提供機関:日本学術振興会

    児玉 竜也, 郷右近 展之

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    配分額:3600000円 ( 直接経費:3600000円 )

    本研究では,従来の高温太陽集熱をエネルギー源とする二段階水熱分解サイクルの反応媒体である水熱分解性セラミックの熱活性に,光半導体触媒の光活性を添加し,水熱分解サイクル反応を低温化することに挑戦した。初年度の研究により,研究代表者が見出した水熱分解性セラミックのFe_3O_4/ジルコニア担持体(Fe含有立方晶ジルコニア,あるいはFe_3O_4/単斜晶ジルコニア)にNiOをドープした水熱分解性セラミック粉体合成に成功し,さらにスピンコーティング法等の方法を応用して,この粉体を材料とした小型発泡体デバイスを作製することにも成功した。さらに,擬似太陽集光を直接デバイスに照射して2段階水分解反応を行う反応デバイスの活性試験を行い,NiOドーブによりデバイスの反応活性が向上することを確認した。今年度は下記の研究を実施する。今年度は下記の研究成果を得た。
    1)作製の成功したFe-Ni含有立方晶ジルコニア発泡体デバイスについて,立方晶ジルコニアに対するNiOドープ量,またFeOドープを変化させ,反応デバイスの反応活性の向上を試みた。反応試験を太陽炉シミュレータで行い,FeO:NiO=2:1のドープ量が反応活性に対して最適なドープ量であることを見出した。
    2)NiO同様に熱力学的見地,および光半導体活性の見地からCoOがFe_3O_4/ジルコニア担持体の反応活性を熱-光ハイブリット活性化によって高めると期待されるため,同様の手法でCoOをドープしたFe_3O_4/ジルコニア担持体粉体を合成し,その水熱分解活性を,赤外線イメージ炉を熱源として試験した。反応活性はほぼNiOドーブ型と同様の活性を得ることが出来た。

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  • 高水熱分解性セラミックとその反応デバイスの開発

    研究課題/領域番号:19360436

    2007年 - 2008年

    制度名:科学研究費助成事業

    研究種目:基盤研究(B)

    提供機関:日本学術振興会

    児玉 竜也, 郷右近 展之

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    配分額:20150000円 ( 直接経費:15500000円 、 間接経費:4650000円 )

    本研究では, 海外のサンベルトの大型集光システムで得られる1400~1 600℃の高温太陽熱を熱源として2段階水熱分解サイクルを行う高水熱分解性セラミック(微粉体)の開発と, その反応デバイス化を目的とした。研究成果として, (1) 研究代表者が見出したフェライト/ジルコニア反応体(微粉体)を基軸として, 水熱分解性セラミック微粉体を, 米(サンディア国立研究所)で開発中のロータリー型分解器と, 日本・韓国(新潟大学・インハ大学)で開発中の発泡体デバイス水分解器のそれぞれのソーラー水分解器の反応体として適応するように改良し, その反応性とサイクル反応性を向上させることに成功した。サンディア国立研究所では, これらの結果からこの新規反応体によるデバイス開発を始めた。
    (2) 一方で, これを日本・韓国(新潟大学・インハ大学)で開発中の新型の発泡体デバイス反応器に利用できるように反応デバイス化し, その発泡体デバイスで2段階水熱分解サイクルを連続的に繰り返し行うことに成功した。反応活性と安定性の両面から総合的に判断すれば, 本反応デバイスは現在最も性能の優れた水熱分解デバイスであると評価できる。さらに韓国(インハ大学)の5kW太陽炉でこの反応デバイスのフィールド試験を行うための大型デバイスを合成すると共に, フィールド試験用のソーラー反応器を設計した。

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  • 反応性セラミック粉体による新型ソーラー水熱分解器の開発

    2006年4月 - 2008年3月

    制度名:科学研究費補助金 若手研究(B)(研究代表者)

    郷右近 展之

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    担当区分:研究代表者  資金種別:競争的資金

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  • 高温太陽熱水分解のための反応性セラミックデバイスの開発

    研究課題/領域番号:17360463

    2005年 - 2006年

    制度名:科学研究費助成事業

    研究種目:基盤研究(B)

    提供機関:日本学術振興会

    児玉 竜也, 郷右近 展之, 清水 研一

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    配分額:14500000円 ( 直接経費:14500000円 )

    サンベルトで得られる高温太陽熱を利用し、水の熱分解で水素を製造する二段階水分解サイクルに必要とされる反応性セラミックデバイスの開発を行い、下記の研究成果を得た。
    1.高反応性セラミック微粉体の開発
    反応性セラミックとして研究代表者が開発したフェライト/ジルコニア担持体について他金属ドープ効果を比較し、高活性のNi_<1.0>Fe_<2.0>O_4/ZrO_4を見出した。一方、研究代表者は、担体を単斜晶ジルコニアから、イットリウム含有量が8mol%以上の立方晶安定化ジルコニア(YSZ)に替えると、熱還元反応においてFe^<2+>含有立方晶ジルコニアが生成し、低温水分解反応ではこれが水蒸気と反応して水素を生成しフェライトではなくFe^<3+>含有立方晶ジルコニアを生成するという新しいサイクル反応機構を見出した。
    2.反応デバイスの合成と反応試験
    Ni_<1.0>Fe_<2.0>O_4/ZrOとFe_3O_4/YSZの2つの微粉末反応体をそれぞれジルコニア発泡体に担持したデバイスを作製し、反応性を検討した結果、熱還元温度1400℃、水分解温度1100℃の2段階サイクル反応で13-30サイクル以上の水素発生が観測された。しかし、次第にデバイスの亀裂が起こった。そこで熱耐久性の高いSiC発泡体をマトリックスとすることとした。
    3.SiC発泡体のジルコニア被覆と太陽光照射耐久試験による性能評価
    熱力学計算からSiC発泡体をFe_3O_4に対して不活性のジルコニアで被覆することが必要であることが見出されたため、スピンコート法によりこれを検討し、良好なジルコニア被覆をすることができた。一方、SiC発泡体マトリックスについては、太陽炉による太陽光照射下試験で良好な熱耐久性を有することが確認された。

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その他研究活動

  • Associate Professor

    2009年4月
    -
    現在

     詳細を見る

    Research institute of promotion/Graduate school of science and technology, Niigata University

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  • Associate Professor

    2005年4月
    -
    2009年3月

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    Graduate school of science and technology, Niigata University

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  • Asistant Professor

    2003年6月
    -
    2005年3月

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    Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology

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  • Research assistant

    2003年4月
    -
    2003年5月

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    Graduate School of Science and Engineering,Tokyo Institute of Technology

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  • Doctoral research fellow

    2000年4月
    -
    2003年3月

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    Research Center for Carbon Recycling & Utilization(Energy), Tokyo Institute of Technology

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担当経験のある授業科目(researchmap)

  • 化学技術英語

    機関名:新潟大学工学部化学システム学科

     詳細を見る

  • 工学リテラシー入門(化学材料分野)

    機関名:新潟大学工学部化学システム学科

     詳細を見る

  • 統合化学入門(副専攻)

    機関名:新潟大学

     詳細を見る

  • ソーラー水素人材育成プログラム「水素エネルギーシステムデザイン演習・実習Ⅰ」

    機関名:新潟大学大学院自然科学研究科

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  • 自然科学総論Ⅱ

    機関名:新潟大学大学院自然科学研究科

     詳細を見る

  • ソーラー水素人材育成プログラム「ソーラー水素エネルギー国際会議コミュニケーション」

    機関名:新潟大学大学院自然科学研究科

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  • エネルギー材料解析化学

    機関名:新潟大学大学院 自然科学研究科

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  • 最先端技術を支える化学Ⅰ

    機関名:新潟大学工学部化学システム学科

     詳細を見る

  • 応用化学演習Ⅲ

    機関名:新潟大学工学部化学システム学科

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  • 物理化学実験

    機関名:新潟大学工学部化学システム学科

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  • 反応速度論

    機関名:新潟大学工学部化学システム学科

     詳細を見る

  • 物理化学Ⅱ

    機関名:新潟大学工学部化学システム学科

     詳細を見る

  • 熱エネルギー材料科学

    機関名:新潟大学大学院 自然科学研究科

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▶ 全件表示

担当経験のある授業科目

  • 国際工学概論

    2024年
    -
    現在
    機関名:新潟大学

  • 熱エネルギー材料科学

    2022年
    機関名:新潟大学

  • エネルギー材料解析化学

    2022年
    機関名:新潟大学

  • リメディアル演習

    2021年
    機関名:新潟大学

  • 技術文献リサーチD

    2020年
    -
    現在
    機関名:新潟大学

  • 技術文献リサーチB

    2020年
    -
    現在
    機関名:新潟大学

  • 技術文献リサーチA

    2020年
    -
    現在
    機関名:新潟大学

  • 技術文献リサーチC

    2020年
    -
    現在
    機関名:新潟大学

  • 熱エネルギー材料科学

    2020年
    -
    2022年
    機関名:新潟大学

  • エネルギー材料解析化学

    2020年
    -
    2022年
    機関名:新潟大学

  • 物理化学実験(工)

    2019年
    -
    現在
    機関名:新潟大学

  • リメディアル演習

    2018年
    -
    2021年
    機関名:新潟大学

  • 工学リテラシー入門(化学材料分野)

    2017年
    -
    現在
    機関名:新潟大学

  • 物理化学II

    2016年
    -
    現在
    機関名:新潟大学

  • 自然科学総論Ⅱ

    2015年
    機関名:新潟大学

  • 水素エネルギーシステムデザイン演習・実習Ⅰ

    2014年
    -
    現在
    機関名:新潟大学

  • 最先端技術を支える化学 I

    2011年
    -
    現在
    機関名:新潟大学

  • 卒業研修

    2009年
    -
    現在
    機関名:新潟大学

  • 反応速度論

    2009年
    -
    現在
    機関名:新潟大学

  • 化学技術英語

    2008年
    -
    現在
    機関名:新潟大学

  • 応用化学演習III

    2007年
    -
    現在
    機関名:新潟大学

  • 卒業研究

    2007年
    -
    現在
    機関名:新潟大学

  • 論文輪講I

    2007年
    -
    2019年
    機関名:新潟大学

  • 物理化学実験

    2007年
    -
    2018年
    機関名:新潟大学

  • 論文輪講II

    2007年
    -
    2018年
    機関名:新潟大学

  • 卒業基礎研究

    2007年
    -
    2008年
    機関名:新潟大学

  • 応用化学実習

    2007年
    機関名:新潟大学

▶ 全件表示

 

学術貢献活動

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    役割:審査・評価

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  • NISTEP専門調査員

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    文部科学省 科学技術・学術政策研究所 科学技術予測センター  2018年4月 - 現在

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    種別:学術調査 

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