This paper describes the overview of technical developments and current policy on fuel cell and hydrogen technology in Japan. First, the outline of current policy programs is laid out. Secondly, it looks back upon technical development policies since the 1960s in Japan. Japanese policy developments are compared with those in other industrialized countries. Lastly, the discussions regarding the future course of technical development of the fuel cell and hydrogen are illustrated based on various opinions expressed at the Fuel Cell and Hydrogen Symposium hosted by New Energy and Industrial Technology Development Organization (NEDO).

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The aim of this work is to develop a high performance heat exchanger type reactor with plate catalysts for proton exchange membrane fuel cell (PEMFC) systems and other applications. Steam reforming of ethanol using silica-coated alumite catalysts on aluminum plates (JIS A3003) was performed in a preliminary study at atmospheric pressure in a temperature range of 300–600°C using a plug flow reactor. Alumite catalysts, prepared by anodic oxidation of aluminum plates, are advantageous for the endothermic reaction of steam reforming because of their good thermal conductivity. However, in an ethanol steam reforming test performed with an alumite support (γ-Al₂O₃/Al plate) or an alumite catalyst (Ni/γ-Al₂O₃/Al plate), ethylene was produced as the main byproduct because of the dehydration reaction of ethanol. In order to inhibit ethylene formation, silica-coated alumite supports (Silica/Al₂O₃/Al plate) and silica-coated alumite catalysts (Ni/Silica/Al₂O₃/Al plate) were prepared using two types of silica sols with different particle size. As a result, the formation of ethylene (C₂H₄) under a condition of the same apparent support/catalyst surface area was reduced dramatically with both the silica-coated alumite supports and the silica-coated alumite catalysts. For example, with the silica-coated alumite catalyst (Ni/Silica/Al₂O₃/Al plate) prepared with a silica sol having a smaller particle size (particle diameter: 8–11 nm), C₂H₄ was reduced by 88% at 450°C, by 45% at 500°C and by 57% at 550°C compared with the levels seen for the alumite catalyst (Ni/γ-Al₂O₃/Al plate). A temperature programmed desorption analysis with ammonia desorption showed that the number of acidic sites per apparent surface area of the silica-coated alumite supports and the silica-coated alumite catalysts was smaller than that of the alumite support and that of the alumite catalyst without any silica coating. These results suggest that the low level of ethylene formation seen for both the silica-coated alumite supports and silica-coated alumite catalysts can be attributed to the smaller number of acidic sites. It is concluded that the silica-coating method is preferable for improving the properties of alumite supports and alumite catalysts for ethanol steam reforming.

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With the aim of developing a non-equilibrium reactor with a CO₂ recovery function for proton exchange membrane fuel cell (PEMFC) systems and other applications, steam reforming of ethanol was performed in a preliminary study in the presence of a CO₂ absorption ceramic at atmospheric pressure in a temperature range of 450–650°C using a plug flow reactor and commercially available reforming catalysts. The CO₂ absorption ceramic consisted of lithium silicate powder, which was granulated and coated with coarse alumina particles. Reaction products were analyzed by gas chromatography. The effects of the CO₂ absorption ceramic on hydrogen selectivity and species concentrations were estimated. It was concluded that steam reforming ethanol in the presence of the CO₂ absorption ceramic has high potential for application to a non-equilibrium reactor. Hydrogen production was enhanced and CO and methane production was suppressed significantly in the presence of the CO₂ absorption ceramic. For example, at a temperature of 500°C and with a commercial FCR-4-02 catalyst, hydrogen selectivity was 1.3 times higher than that in the absence of the CO₂ absorption ceramic, and the hydrogen concentration was 95 mol%-dry. This hydrogen concentration was considerably higher than that at chemical equilibrium, which was 63 mol%-dry. The methane concentration decreased from 10 to 4.2 mol%-dry, and the CO concentration decreased dramatically from 2.0 mol%-dry to less than the detection limit, which was about 100 ppm. The CO and methane concentrations were considerably lower than those at chemical equilibrium, which were 3.4 and 11 mol%-dry, respectively. These results indicate the potential for constructing a fuel processor system, which will not need either a high-temperature shift reactor (HTS) or a low-temperature shift reactor (LTS), for PEMFC applications.

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Hydriding combustion synthesis (HCS), which utilizes self-propagating exothermic reaction between metallic powders at pressurized hydrogen, was originally developed for metal hydride production. It offers many advantages to save processing time, to reduce productive cost, and to synthesize high purity product. In this paper, a feasibility study of HCS was conducted by means of enthalpy-exergy diagram, in which Mg₂NiH₄ was selected as the final product. We estimated the exergy losses of two metal hydride production systems: One was HCS, and the other was conventional method composed of a melting process and so-called activation treatment. As a result, the total exergy loss (EXL) of HCS was found to be 230 kJ/mol-Mg₂NiH₄, which is less than 11% of EXL in the conventional method. This difference between EXLs of the systems was due to the activation treatment in the conventional method, where cast Mg₂Ni was repeatedly hydrogenated and dehydrogenated. Since ingot metal hydrides require activation treatment, the conventional method becomes quite inefficient. On the other hand, the HCS product does not require the activation treatment, thus, it is quite attractive from the viewpoint of cost efficiency.

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A feasibility study of the hydrogen production from high temperature waste heat in the steel industry is carried out from the viewpoints of thermodynamics and economics. The waste heat of molten slag is chemically recovered by endothermic methane-steam reforming. To recover the sensible/latent heat of molten slag directly, it is granulated by a spinning disk atomizer and is cooled by a mixture of steam and methane. In this study, exergy analysis of the proposed system was conducted on the basis of the total unrecovered waste heat. A simple heat and material balance model was employed to evaluate the possibility of Japanese steelworks as a hydrogen station by calculating exergy loss and cost benefit. The results show that the proposed heat recovery system for the production of hydrogen has a less exergy loss of only 12% as compared to the unrecovered system. It also gives a cost benefit totaled US$ 277 million based on the annual steel production of 102 million tons. The results also offer a possibility for hydrogen production with high cost performance by utilizing waste heat from high temperature industries.

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To know the movement of water in the Polymer Electrolyte Fuel Cell (PEFC) is important for deciding the optimum shape of the cell and the operating condition. It is well known that the PEFC shows the best performance under a moderate relative humidity condition. However, the experimental measurement is difficult because of the flow through the complex geometry of the diffusion layer. Therefore, in order to know the movement of water in the PEFC, a microscopic analysis was performed by a lattice gas automata (LGA) method. The influence of gas diffusion prevention by water was investigated. In addition, the relationship between the reaction time and the reaction quantity for a PEFC with a dry membrane was investigated. The reaction quantity, which had increased due to the membrane getting more wet by water generation, decreased due to the prevention of gas diffusion by water, and after a while, it settled into a steady state. According to the channel shape, distribution of water was observed in the diffusion layer and it affected the distribution of oxygen and hydrogen reaction quantity. Moreover, since the influence of the gas diffusion prevention by water on the cathode side was more dominant than that on the anode side, it was shown that the concentration overpotential of the cathode side strongly affects a cell performance.

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Coal-integrated gasification/gas turbine (CIG/GT) based power plants are well known for achieving electricity more efficient and at a lower cost than direct combustion based power plants. Since the gasification is an endothermic, thermochemical conversion process, it requires heat to proceed. In general, this heat is furnished by internal combustion taking place in the gasifier by virtue of oxygen-blown or air-blown gasification. However, the direct combustion of the solid fuel is seen to be inefficient because of the large amount of exergy destruction posed during the combustion, especially at relatively low temperatures like gasification temperatures. This causes the overall performance deterioration of the CIG/GT system. Therefore, a decrease in the destruction of exergy during the combustion can contribute to improve overall system efficiency. In this paper, an innovative concept of energy-recuperative gasification was proposed and incorporated in the CIG/GT system. The idea is to make use of the waste heat from the gas turbine exhaust as the reaction heat for the gasification instead of the internal combustion. This type of energy recuperation is also called thermochemical recuperation. In addition, the proposed CIG/GT incorporates other effective energy recuperation, including heat and steam recuperation, in order to maximize the generation efficiency. The feasibility of the concept implementation and the system improvement were preliminarily examined and discussed.

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The thermochemical water decomposition process is a very interesting process for hydrogen production from water using a primary thermal energy source. Solar thermal energy and nuclear thermal energy are principal candidates for the thermal energy source for this process and a carbon-free energy system can be established using these energy sources. A Ca-Fe-Br thermochemical hydrogen production process named a UT-3 cycle is the most promising one. It consists of four gas–solid reactions. Two of them are using Fe compounds and others are using Ca compounds as solid reactants. It is important to improve these solid reactants in order to industrialize this process. Low reactivity of Fe₃O₄ to FeBr₂ and sublimation of FeBr₂ were main problems. A new method using a sol–gel reaction, an alkoxide method was introduced to prepare Fe compounds instead of a conventional powder mixing method. The amount of additives and the molar ratio of the reactant to the binder material during a process of the alkoxide method were investigated to find an optimum preparing condition. Durability of the Fe-compounds in cyclic reactions was studied. A reaction analysis for the bromination reaction was also conducted.

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A sensitivity analysis of the operation parameters and the chemical properties in the thermochemical hydrogen production IS process (iodine-sulfur process) was carried out for a static flow sheet. These parameters were evaluated by hydrogen production thermal efficiency, the mass flow rate or heat exchange based on the heat/mass balance. The most important parameters were the concentration of HI after electro-electrodialysis (EED) and the apparent transport number of protons of the cation exchange membrane in the EED cell. HI concentration operation should be operated carefully because the parameters for optimum thermal efficiency and for the optimum flow rate and heat exchange were different. For the chemical properties, composition at the inlet of the HI decomposition procedure and HI_x pseudo-azeotropic composition had great effects. The HI concentration after the EED should be optimized for each composition. The order of priority for the assessment of the operation parameters and chemical properties was determined by the evaluation.

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The decomposition of methane for hydrogen production over a Co–Mo catalyst with 25% Co loading carbided at various temperatures was studied at 973 K and atmospheric pressure. The 700 K-carbided catalyst was the most active of the other catalysts for H₂ production (above 98%) in the decomposition at 44 h. The Co–Mo catalysts carbided at 725 and 750 K were also active at 44 h, while the catalyst carbided at 800 K was active for 1 h but quickly deactivated. The catalysts carbided at 873 and 973 K were less active. The XRD analysis showed that the catalysts carbided at 700–750 K consisted of MoO₂ and CoMoO₄ which were turned to CoMoO_xC_y, β-Mo₂C, and Co metal during the CH₄ decomposition. The carbiding at 800 K produced CoMoO_xC_y which changed to β-Mo₂C and Co metal after the reaction. The carbiding at 873 and 973 K contained β-Mo₂C and Co metal. The effects of two carbiding methods of different heating rates, H₂ pretreatment, and CO₂ addition on the catalytic activity and hydrogen production were studied.

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The formation of hydrogen during methane conversion on supported Mo nitride catalysts was studied using a flow microreactor at 973 K and atmospheric pressure. The catalysts before and after the reaction were characterized by XRD, temperature-programmed reduction with H₂ (TPR), and temperature- programmed surface reaction with CH₄ (CH₄-TPSR). Based on the catalytic activity effect of the supports (Al₂O₃, SiO₂, TiO₂, and ZSM-5), the ZSM-5 supported Mo nitride catalyst was the most active for hydrogen production. Mo nitride was partially transformed into Mo carbide at 973 K during the CH₄ decomposition. The addition of Co and Ni atoms to Mo/Al₂O₃ promoted the CH₄ decomposition activity due to the high hydrogen activation performance by the creation of Co(Ni-) added γ-Mo₂N or Co(Ni)–Mo nitride in nitridation and the formation of Co(Ni)-added η-Mo₃C₂ or Co(Ni)-Mo carbide on the surface during the reaction.

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The effects of heat-shock conditions on the characteristics of fermentation using granular sludge were examined. The granular sludge was obtained from the wastewater treatment plant of a brewery factory. The temperature and time of heat-shock treatment were changed in the ranges of 60–90°C and 0–60 min. The pH at heat-shock treatment was varied from 3 to 10. Glucose was used as the substrate. The yield and selectivity of hydrogen for the heat-shocked granular sludge were much higher than those for the non heat-shocked granular sludge. In the present fermentation, the optimum conditions of heat-shock treatment for granular sludge were 70°C, 30 min and pH of 6. The hydrogen yield for the second heat-shocked granular sludge was lower than that for the first heat-shocked granular sludge. It was found that a relatively long period for the spore formation before the heat-shock treatment was needed to enhance the hydrogen yield.

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