ピンボール 木の豆ミックス2

Journal of the Hydrogen Energy Systems Society of Japan
Online ISSN : 2436-5599
Print ISSN : 1341-6995
Volume 25, Issue 1
Displaying 1-14 of 14 articles from this issue
  • [in Japanese]
    2000 Volume 25 Issue 1 Pages 1
    Published: 2000
    Released on J-STAGE: July 21, 2022
    DOI
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  • Mikimasa Yamaguchi, Taizo Shinohara, Harutaka Taniguchi, Hirotaka Naka ...
    2000 Volume 25 Issue 1 Pages 3-11
    Published: 2000
    Released on J-STAGE: July 21, 2022
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    In WE-NET, a water electrolyzer with a solid polymer electrolyte membrane is expected to produce a large volume of hydrogen per unit. The final performance target the electrolyzer is as follows: Electrode area 10,000 cm2/cell, Current density ≈ 1 to 3 A/cm2, Energy efficiency >90%. To achieve this target, we have been developing for manufacturing membrane electrode assemblies by a hot-press method to decrease electrolysis voltage, and technologies for fabricating support collectors to minimize the IR drop of cells. Recently, using these technologies, we have obtained a high-performance large-scale electrolyzer having five stacked cells with 2500-cm2 electrodes. This electrolyzer has demonstrated a high electrolysis performance, exceeding the target of WE-NET. It registered an energy efficiency of 94.4% for a current density of 1 A/cm2 at a temperature of 80°C under atmospheric pressure.

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  • Masahiko KAWAGUCHI, Yasuhiro NITO, Yasukazu SAITO
    2000 Volume 25 Issue 1 Pages 12-17
    Published: 2000
    Released on J-STAGE: July 21, 2022
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    Catalytic cyclohexane dehydrogeno-aromatization was performed at waste-heat temperatures such as 180℃ under boiling and refluxing conditions. In spite of the limitation of equilibrium conversion (3.6%) for yielding benzene and hydrogen, higher conversions were attained in a short period as the consequence of reactive distillation. Under the catalyst conditions of so-called “liquid-film state”, carbon-supported composite catalysts between Ir cluster complex and Pt nanosize metal attained the conversion as high as 78% within the reaction period of 5 h.

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  • Satoshi Fukada, Shinsuke Morimits
    2000 Volume 25 Issue 1 Pages 18-23
    Published: 2000
    Released on J-STAGE: July 21, 2022
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    Mass and heat transfer rates in two types beds packed with Zr-V-Fe alloy particles are investigated in experimental and analytical ways for heat pumps operated at higher temperatures. The constant pattern approximation is applied to the hydrogen concentration (or hydrogen pressure) and temperature profiles in smaller and larger beds. The partial differential equations are reduced to ordinal differential equations under proper assumptions. The mass-transfer rate in the smaller bed is correlated in terms of two mass-transfer capacity coefficients and the heat-transfer rate in the larger bed is in terms of two dimensionless parameters, a and β. A set of analytical solutions was obtained for the hydrogen concentration and temperature with the coherent profile. The experimental profiles were well flitted by those of the numerical or analytical solutions.

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  • Tsutomu ISHIKAWA, Masataka MASUDA, Yasunori HAYASHI
    2000 Volume 25 Issue 1 Pages 24-28
    Published: 2000
    Released on J-STAGE: July 21, 2022
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    Copper Nitride(Cu-N) thin films were prepared by reactive r.f. sputtering. With controlling the content of nitrogen gas, the electrical and optical properties of Cu-N thin films were changed. Stoichiometric Cu3N thin films were found to be formed at 40% nitrogen gas because of the highest electrical resistivity and the largest optical band gap energy of all samples. Hydrogen ion implantation treatment was done in order to investigate the effect of hydrogen in Cu-N thin films on the electrical properties such as electrical resistivity and carrier density. After the treatments, the electrical resistivity of stoichiometric Cu3N thin film was drastically decreased as the carrier density was increased.

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  • Makoto SAKURAI, Saburo SHIMIZU
    2000 Volume 25 Issue 1 Pages 29-36
    Published: 2000
    Released on J-STAGE: July 21, 2022
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    Possibility of hydrogen production by water electrolysis using nuclear off—peak power was studied. Cost of nuclear off-peak power was estimated using various cases of plant operating pattern for supplying off-peak power and power plant working ratio. The relationship between cost of electricity and cost of hydrogen produced by water electrolysis process was evaluated on the basis of plant data of different types of water electrolysis hydrogen production, alkaline solution electrolyser and solid polymer electrolyte membrane. The effect of plant availability of electrolyser on the hydrogen production cost was also investigated. By connecting those evaluations, a case study was conducted for the cost of hydrogen production by water electrolysis using nuclear off-peak power. The cheapest case was almost 20 yen/Nm3-H2. It was found that hydrogen production using nuclear off-peak power has a great possibility.

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  • Hideki Hotta, Tashiro Kuji, Hirohisa Uchida
    2000 Volume 25 Issue 1 Pages 37-40
    Published: 2000
    Released on J-STAGE: July 21, 2022
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    Thermodynamic properties of LaNi5-x(Mn,Al,MCo)x(x=0-1.0) alloys-H systems were determined by the measurements of pressure-composition(PC) isotherms. It is well known that the replacement of a fractional part of Ni in LaNi5 and MmNi5 alloys by other transition elements causes increase or decrease in the unit cell volume due to the change in size of interstitial holes, which leads to the variation in the stabilization of hydride, corresponding to the plateau pressure[1,2]. In this study, calculated chemical potential of hydrogen was separated into the chemical potential of infinite dilute solution and excess chemical potential of hydrogen[2]. It was found that chemical potential of infinite dilute solution is dominant to control the plateau pressure. This is consistent to the relation between plateau pressure and unit cell volume, indicating that plateau pressure could be estimated from the alloy structure, before absorbing hydrogen.

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  • Hirohisa Uchida, Kohji Okada, Masanobu Gotoh, Kohichiro Yamashita
    2000 Volume 25 Issue 1 Pages 41-45
    Published: 2000
    Released on J-STAGE: July 21, 2022
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    This paper reports a new mechanism of the initial activation of hydrogen storage alloys by alkaline treatment of the alloy surface. The surfaces of LaNi5 and LaNi2.5Co2.5 alloys were treated with an 8M KOH solution. This treatment yielded the penetration and distribution of K atoms in surface oxide layers. With increasing concentration of K atoms in the surfaces, the work function of electrons of the surfaces became reduced over 1.0eV This reduction in work function was found effective to the increasing the initial reaction rate. Based on measured kinetic results in the gas phase and electrochemical processes, and also from results of the surface analyses of the alloys using AES and XPS, a new mechanism of the activation by alkaline atoms in the surface region is proposed.

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  • Masahiro Hadano, Shoichi Terada, Nobuaki Urushihara, Tatsuhide Inoue, ...
    2000 Volume 25 Issue 1 Pages 46-48
    Published: 2000
    Released on J-STAGE: July 21, 2022
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    The reaction probability, r, of H2 with the surface of rare earths (La, Ce, Tb, Dy) was measured by a volumetric method at 298K under ultra high vacuum condition. Initially, the surfaces of these metals exhibited the highest value, r=1. With increasing amount of hydrogen adsorbed and/or absorbed, r was decreased and then exhibited plateaux at r=10-1-10-2 where the two phases of H solid solutions and d.ihydride may coexist. Thereafter, r sharply dropped for each system. The Ce surface with the O2 preadsorption layers exhibited the highest H2 reactivity among those of the rare earths samples.

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  • Tsugihiko TAKUMI, Yukihiko MATSUMURA
    2000 Volume 25 Issue 1 Pages 49-54
    Published: 2000
    Released on J-STAGE: July 21, 2022
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    Biomass is expected to be a cheap and renewable source of hydrogen. Especially, wet biomass such as sewage sludge and water hyacinth is a good candidate for feedstocks of hydrogen production. Supercritical water biomass gasification process, which has been shown to be suitable for wet biomass processing, is further analyzed to determine the location in the process and the amount of the exergy losses taking place. The result is presented to show the validity of improving the process efficiency with expected cost increase for the purpose. Cost versus exergy efficiency curve is drawn to show the possibility of wet biomass utilization.

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  • Koji Hashimoto, Michiaki Yamasaki, Tetsuro Matsui, Koichi Izumiya, Shi ...
    2000 Volume 25 Issue 1 Pages 55-63
    Published: 2000
    Released on J-STAGE: July 21, 2022
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    We are proposing global carbon dioxide recycling which gives a final solution not only to avoid global warming but also to supply abundant energy. Power generation by solar cell on only less than 1 % of the main desert area on the Earth is sufficient for generation of electricity necessary for all people in the whole world. Because the electricity cannot be transmitted more than 500 km, at the seaboard of deserts the electricity will be used for hydrogen production by seawater electrolysis. Since hydrogen combustion facilities are not widely distributed, hydrogen will be used for production of methane by the reaction with carbon dioxide, methane being used widely as liquefied natural gas. After combustion of methane, carbon dioxide will be recovered at large fuel combustion plants at energy consuming districts and sent back to the seaboard of the deserts. Key materials for global carbon dioxide recycling are active cathodes for hydrogen production in seawater electrolysis, stable anodes for oxygen evolution without chlorine evolution even in seawater electrolysis and active catalysts for production of only methane from carbon dioxide. We succeeded to tailor these key materials and substantiated the idea by building a prototype plant which has successfully been operating since March 1996.

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  • Hiroyuki HARADA
    2000 Volume 25 Issue 1 Pages 64-69
    Published: 2000
    Released on J-STAGE: July 21, 2022
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    The destruction of earth environment such as green-house effect and acid rain is a serious problem for the human-beings in 21st century. This problem is caused by over discharge of the carbon-dioxide, nitrous oxide, sulfureous oxide by the petroleum combustion to get sufficient energy for satisfying today’s human activity. The settlement of this problem is necessary ;to stop the use of petroleum and develop the new clean energy to be able to replace it.

    Hydrogen has a feasibility of a clean energy to be able to replace the petroleum. HHOG, high-pressure hydrogen oxygen generator, can generate high-pressure hydrogen and oxygen without any gas compressor. So, HHOG is a suitable hydrogen generator for the replacement of the petroleum.

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  • Yasukazu SAITO
    2000 Volume 25 Issue 1 Pages 70-77
    Published: 2000
    Released on J-STAGE: July 21, 2022
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    Storage and transportation of hydrogen or waste heats have been discussed in terms of hydrogen energy systems assisted by catalysis. Hydrogen evolution from decalin as a liquid hydride (7.3 wt%) proceeded efficiently with catalysts in liquid-film states under 200℃-boiling conditions. A chemical heat pipe at a 200℃ level from factory-to urban-areas was designed with a reversible set of methanol decomposition and synthesis, whereas a chemical heat pump had been proposed with the catalysis couple of 2-propanol dehydrogenation and acetone hydrogenation by upgrading thermal energy from the low-quality level of 80~90℃ up to the temperature as high as 150-200℃ at the sacrifice of heat removal into ambience.

    Its Gibbs energy was recoverable in fuel cells (H2→ 2 H+ + 2 e- or (CH3)2CHOH→(CH3)2CO + 2 H+ + 2 e-; (CH3)2CO + 2 H+ + 2 e-→ (CH3)2CHOH), which were thermo-regenerative by means of 2-propanol dehydrogenation or fractional distillation of acetone from 2-propanol. Importance of thermodynamical coupling between heat and mass transfers at the superheated catalyst interface was pointed out with reference to these vector-type irreversible transfer processes.

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  • Koichi FUKUO, Akira FUJIMURA, Masaaki SAITO, Kazuhiko TSUNODA, Shiro T ...
    2000 Volume 25 Issue 1 Pages 78-86
    Published: 2000
    Released on J-STAGE: July 21, 2022
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    For the global environment preservation, the model has been developed with the objective of reducing CO2 in the exhaust, in other words, sparing on fuel, to 1/2 of Honda’s typical low-fuel- consumption car CIVIC. A variety of new technologies have been developed on the basis of new scheme of hybrid power train, e.g. relating to improvement in thermal efficiency for engine, weight reduction for vehicle body and reduction of aerodynamic drag, resulting in extreme fuel economy of 35km/L at 10-15 mode. Also, the exhaust emission attains as low as 1/2 of 2000 Japanese exhaust emission regulation. Additionally, due consideration was given to its recycling capability, safety performance in crash, comfortable running and the styling to be highly sophisticated ultra-low-fuel-consumption hybrid car.

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