A passively-fed methanol steam reformer heated with two-stage bi-fueled catalytic combustor

摘要

This paper presents further progress on our simple novel passively-fed methanol steam reformer. The present study focuses on the development of a catalytic combustor workable with both hydrogen and methanol fuels. The aim is to reutilize the exhaust hydrogen from a fuel cell under stable operation but burn methanol during the start-up. On a copper plate, the catalytic combustor in a u-turn channel is integrally machined under a two-turn serpentine-channel reformer. To resolve the highly different fuel reactivities, a suitably diluted catalyst formula demonstrates uniform temperature distributions burning with either liquid methanol or an H_2/CO_2 mixture simulating the exhaust gas from a fuel cell. In a two-stage process, it first takes 25 min to reach 270℃ by burning methanol. After the fuel is switched to the H_2/CO_2 mixture, another 20 min is needed to attain an optimal steady state which yields a high methanol conversion of 95% and acceptably low CO fraction of 1.04% at a reaction temperature of 278 ℃. The H_2 and CO_2 concentrations are 75.1% and 23.6%.