To produce hydrogen from sewage, aerobic evolution of hydrogen by Enterobacter aerogenes st. E.82005 was examined at the condition of unsuitable nutrient and pH for growth. E. aerogenes evolved hydrogen for more than 40 minutes under aerobic condition, DO concentration ca. 5.8mg/l. It used dissolved oxygen immediately after inoculation, though it had been cultivated under anaerobic condition. From this result, the TCA cycle and electron-transport chain were fund to be preserved even under anaerobic condition. The termination of hydrogen evolution at aerobic condition was explained as the oxidation of NADH turned from hydrogen evolution to the respiration.

Steam reforming of hydrocarbons is industrially important and is a widely used reaction for producing hydrogen or synthetic gas. Conventional hydrogen production system fueled with natural gas or city gas is composed of steam reformer, water-gas shift converter and hydrogen purification system. Steam reformer equipped with palladium membrane can perform steam reforming and hydrogen separation processes simultaneously, and enables hydrogen production directly from city gas. This reformer is expected to provide an advanced hydrogen production system without water-gas shift converter and hydrogen purification system.

We have developed a metal hydride(MH) actuator that uses the reversible reaction between the heat energy and mechanical energy of a hydrogen absorbing alloy. The MH actuator has a large output per weight unit and is noiseless and smooth-acting. Therefore, the MH actuator is suitable for use in medical and rehabilitation applications.

In this paper, the features of the MH actuator and the applications to a wheelchair with lifter, a toilet lifter and a toilet seat lifter are introduced.

Palladium and LaNi_4.7Al_0.3 were proved to be promising materials for hydrogen isotope separation from experimental results of the isotope separation factor, the isotope exchange rate constant and the height equivalent to a theoretical plate(HETP). Although the displacement chromatography using a single column packed with Pd particles is an efficient separation method, it could not separate hydrogen isotopes continuously. The twin-column periodically counter-current flowing method developed here was proved to serve a continuous, efficient method for the separation of hydrogen isotope mixtures, experimentally as well as numerically.

Taking into account of the well-established commercial process of naphthalene perhydrogenation to decalin, endothermic catalysis of decalin dehydrogeno-aromatization has been investigated under mild reaction conditions (200～210℃, 1atm), with a carbon-supported platinum-tungsten composite catalyst revealed to be active for hydrogen evolution from decalin to naphthalene under boiling and refluxing conditions. A new approach for economical long-distance transportation or long-term storage of hydrogen is discussed on this basis.

Using simplified load duration curve and solar radiation profile as parameters, economic feasibility of a photovoltaic solar-hydrogen power system(PVHS) was investigated. The required power capacity for each system component was determined by the linear programming method, and the >capital costs were computed. The total capital cost of the PVHS showed that stand-alone PVHS can be economically feasible in many circumstances.

There are two methods to improve the volumetric efficiency of a high pressure liquid hydrogen pump operating in liquid hydrogen. One is to improve the suction efficiency and the other is to decrease the leakage through the clearance between the piston and the cylinder of the pump. A suction booster was applied to the high pressure liquid hydrogen pump to obtain much greater suction efficiency. And a piston ring sealing was also applied to obtain much smaller leakage. It has been found in our experimental study that the two methods have contributed to the increase of the volumetric efficiency to a large extent.

Hydrogen production by gasification of biomass and waste organic compounds in supercritical water is a promising technology for utilization of wet organic compounds which cannot be used as a fuel because of its high moisture content. Catalytic as well as non-catalytic gasification has been investigated, and a high gasificaiton conversion was achieved Product gas is mainly composed of hydrogen, carbon dioxide, carbon monoxide, and methane. In order to obtain a high yield of hydrogen, methane generation should be repressed and water-gas shift reaction should be enhanced. Removal of carbon dioxide from hydrogen using only high-pressure water and utilization of nickel catalyst is also discussed.

To Control the rise in CO₂ concentration in our environment, we are now focusing on “Project of CO₂ Fixation and Utilization Using Catalytic Hydrogenation Reaction”. This project aims at the reduction of CO₂ emission and the establishment of such a system that can work as a countermeasure against our future fossil fuel depletion problem.

This paper will explain the outline of the study of chemical CO₂ fixation project and it’s total system which will be the new CO₂ control system to be developed.

Protonics deals with the science and technology of protons in motion. A proton conducting ceramic is one of the promising advanced materials for energy saving and environmental conservation in the future. In this paper, the possibilities of protonics as a technology are surveyed and high temperature proton conducting oxide ceramics for them are reviewed with respect to materials, their electrochemical properties and their applications citing mainly the experimental results in the author’s laboratory.

The RAV4 EV is a genuine electric vehicle designed for the most practical use in both city and highway traffic. It incorporates a new Nickel-Metal Hydride (Ni-MH) battery, which offers a driving range of over 200 km. To ensure its market adaptability in areas of the world, we has started two-year monitoring programs since the end of 1995 in several cities of Japan and the United States of America. The initial test results brought us great belief in its progressed performance in real market application. This paper outlines the resign concept of the vehicle system, aimed at minimizing its energy consumption and maximizing battery life, and also describes the results of the monitoring tests and fmdings on the following issues.