Tokyo Gas has been conducting intensive research and developments of fuel cells including polymer electrolyte fuel cell (PEFC). PEFC has desirable characteristics, such as easy start-up and shutdown, compactness and light-weight etc., for a small scale co-generation system (co-gen). Counting on them, R&D on natural gas fuelled PEFC co-gen for residential application in Japan has been conducted. Our activities relating to residential PEFC co-gen include establishment of a specification of PEFC co-gen fitting market requirements, development of integrated fuel processors, and evaluation of the performance through operation tests and field trials. In this paper, these activities towards the first market introduction is reported.

Osaka Gas has been developing PEFC cogeneration system for Japanese residential market since 1999, and we have developed its fuel processor and CO preferential oxidation catalyst for this application. The fuel processor has already achieved the targeting thermal efficiency, which is above 82% (HHV), its targeting durability over 90,000 hours can be also expected from our test results, and. CO concentration is reduced below 1 ppm.

Since the year before last, we have started the joint development programs individually with four promising manufactures. So, we will introduce these activities of PEFC cogeneration systems development.

Based on previous research and development, Nippon Oil Corporation (NOC) has been developing stationary Polymer Electrolyte Fuel Cell (PEFC) systems that use petroleum fuels since 1999.

NOC have developed a 1-kW class powered petroleum gas (LPG) powered stationary PEFC system was co-developed with SANYO Electric Co., Ltd. Under a joint development and started commercial sales in March, 2005. The power generation efficiency of the unit is 34%. The total energy efficiency is achieved to 76% in this unit by the heat recovery system. NOC will install 150 fuel cell systems within 2005 fiscal year.

In April 2004, kerosene powered 1kW PEFC stationary demonstration system was co-developed with EBARA Ballard CORPORATION under a joint development. The power generation efficiency of the unit is 33%. The total energy efficiency is achieved to 76% in this unit by the heat recovery system. The system was also tested below freezing point and was confirmed operability without any problem. A power generation efficiency of 36% will be achieved as a target in the next generation. After realizing an improvement of electrical efficiency and overall efficiency and downsizing, and passing through a field examination from now on, the early market injection is aimed at.

Kerosene is one of the most attractive fuels for stationary fuel cells in terms of infrastructure and the fuel price, and as a result running-cost. Relatively high carbon/hydrogen ratio and sulfur content of kerosene, however, bring a disadvantage in reforming activity. To overcome this disadvantage, Idemitsu has developed an advanced fuel processing technology for kerosene. Using the reforming technology, we assembled PEFC co-generation systems in cooperation with fuel cell makers and started field test of the systems at some commercial facilities. In this paper, we present our technology for kerosene PEFC systems, especially the results of the field test.

The introduction of residential fuel cells has been just became a realistic option in Japan. Research and development is at the final stage before commercial market launch.

This paper presents the concept of the interconnection of homes with energy networks of electricity, heat (hot water) and hydrogen, and experimental systems and PC simulators for evaluating the advantages and disadvantages of the networks in providing more efficient use of fuel cells and more CO2 mitigation. Homes can share their energy equipment via the networks. Sharing provides flexible and efficient operation of the equipment, and reduces partial load operation and start-stop operation, which damage the efficiency or the life time of fuel processors.

A new thermo-chemical and electrolytic hybrid hydrogen production system in middle temperature range is newly proposed to realize the hydrogen production from water by using the heat generation of sodium cooled Fast Breeder Reactor (FBR). The system is based on sulfuric acid synthesis and decomposition process developed earlier (Westinghouse process), and sulfur trioxide decomposition process is facilitated by electrolysis with ionic oxygen conductive solid electrolyte to reduce the operation temperature 200°C-300°C lower than Westinghouse process. Experimental apparatus to substantiate the hydrogen production system was manufactured, and several hydrogen production experiments were performed. Maximum operation duration was about 5 hours, and almost stable generation of hydrogen and oxygen was observed. Hydrogen and oxygen production rate in the experiments was about 5ml/h and 2.5ml/h, respectively.

A catalysis pair of decalin dehydrogenation and naphthalene hydrogenation is proposed as a storage medium of hydrogen for operating vehicles powered by hydrogen-fueled internal combustion engines and fuel cells in stationary modes. The energy densities with decalin (7.3 wt%, 64.8 kg-H₂/m³) are higher than the target values of the U.S. Department of Energy (6.5 wt%, 62.0 kg-H₂/m³). In order to establish a practical process for hydrogen supply from decalin in the present study, an activated carbon cloth was adopted as a new supporting material because of its handling advantages, instead of granular activated carbon. Platinum nano-particles supported on activated carbon cloth in superheated liquid-film states under reactive distillation conditions gave high dehydrogenation activities in batch-wise and continuous operations at heating temperatures of 210-280°C.

A sulfur-based hybrid cycle for electrolysis in a H₂SO₄solution and thermal decomposition in high temperature gas-cooled reactor is considered to be a large hydrogen producing process with high efficiency. The electrodes of the electrolysis must satisfy the following requirements; (1) high corrosion resistance under electrolysis condition, (2) high electrical conductivity, and (3) low anodic overpotentials for proton reduction. In this paper, an application of electronic conductive ceramics, non-stoichiometric RE_2-xTi₂O_7-ටි pyrochlores (RE: rare earth metal) and B-site doped and non-stoichiometric RE_2-xTi_2-yMyO_7-ටි pyrochlores (M: transition metal), to the substitute anodes for platinum group material was investigated from the viewpoint of corrosion resistance in the H₂SO₄solution and electrical conductivity at 353K.

The establishment of a quality standard for hydrogen fuel is considered a prerequisite for the widespread use of fuel cell vehicles (FCVs). In this regard, it is necessary to set an allowable content of each impurity in hydrogen fuel, since impurities are believed to affect the electric generation and durability performances of fuel cells. In this study, the concentrations of impurities in hydrogen fuel were measured and their influences on the electric generation of single cell were investigated. In a 10-hour electric generation test at a high constant current density of 1,000mA/cm², the concentration at which the generated electric voltage declined was determined for each impurity. The upper content limits or maximum allowable values of impurities were determined in view of their accumulation in hydrogen circulation systems.

In order to keep the safe operation of a hydrogen infrastructure, we have developed the method that pinpoints the exact location of hydrogen flame and gas. This method creates a visible imaging of a hydrogen flame and gas combining the technologies of an amplification of ultraviolet light and its conversion into visible light, utilization of laser and image processing.

As one of the hydrogen stations for JHFC (Japan Hydrogen and Fuel cell Demonstration) project that is supported by METI (Ministry of Economy, Trade and Industry), Japan Air Gases is operating the JHFC Kawasaki hydrogen station that has methanol reforming on-site hydrogen generator. This paper describes experience of operation of the JHFC Kawasaki hydrogen station mainly safety handling of hydrogen.