PROCESS DEVELOPMENT OF HYDROGENOUS GAS PRODUCTION FOR PEFC FROM BIOGAS

摘要

A three years lab-scale development research project partially financed by the Ministry of agriculture, Forestry and Fisheries of Japan is under way to develop an electricity-heat cogeneration system that uses polymer electrolyte full cell (PEFC) as the electricity converter and biogas as the fuel. The key task of the project is to design and test a gas producing process that consists of a desulfurizer, a steam reformer (SRr), high and low temperature water gas shift reactors (HTWSr and LTWSr) and a selective CO oxidizer (SOr) to produce hydrogenous gas from anaerobic-digestion biogas for a 50W class PEFC. This paper concerns the latter four catalytic reactions and aims at integrating these component reactions into a gas processor that generates hydrogenous gas steadily with H_2 at a rate of >1.0 L/min and CO less than 10 ppm for the PEFC. For this purpose, a four reactors gas processor that allows the mentioned reactions being tested not only simultaneously in one experiment but also independently with different, simulated feed compositions was designed in this study on the basis of the previous observations using micro quartz reactors. After its construction, the operating conditions, especially space velocities, were first determined for each of its reactors with different commercial catalysts in their original shapes and sizes, and this in turn led to the data more valuable for its scale-up in future. Finally, a 7 hrs continuous test running the four reactions simultaneously was conducted to confirm the stabilities of the used catalysts.