NEW CONCEPT HYDROGEN PRODUCTION SYSTEM BASED ON THE MEMBRANE REFORMER

摘要

A membrane reformer with a rated hydrogen production capacity of 15 Nm~3 h~(-1) has been developed. Palladium alloy, which allows only hydrogen to pass through, is fabricated into membranes and used in the reformer for direct production of high-purity hydrogen from city gas. With a new concept of simultaneous generation and separation of hydrogen, the membrane reformer can be made compact and requires less installation space than the conventional ones. Simultaneous progress of hydrogen generation and separation can make the reaction free from the limitation of chemical equilibrium and thus reduce the reaction temperature from conventional 973～1073 K to 773～823 K. This in turn allows lower fuel consumption and use of inexpensive structural materials, which leads to high economy of the system. The operation tests of the membrane reformer have demonstrated the hydrogen production rate of 14 Nm~3 h~(-1) as had been designed, the product hydrogen purity of over 99.999%, and stable unmanned continuous operation of over 1,000 hours. These results suggest that the membrane reformer can be made compact to only about 1/5 of the conventional system and can simply produce high-purity hydrogen, which has led us to believe that the membrane reformer can suitably be applied to fuel processor systems for polymer electrolyte fuel cells (PEFC) and hydrogen refueling stations for fuel cell electric vehicles (FCEV).