Exergy Enhancement of Low Temperature Waste Heat by Methanol Steam Reforming for Hydrogen Production

摘要

Steam reforming of methanol at low temperature was examined for the purpose of recovering and using low quality waste heat [ < 300℃] as a higher quality chemical energy of hydrogen. A large exergy enhancement of waste heat can be realized by this endothermic process. Although methanol conversion can reach to 100% at 100℃ theoretically, the existing system requires at least 250℃ to maintain enough reaction rate and reactivity of catalyst, and lower temperature is preferable to recover lower quality waste heat. In this study, a membrane reactor was applied for steam reforming of methanol to enhance reaction rate at lower temperatures. Methanol conversion increased by 5-10% at the temperature level of 100℃ - 200℃ (160℃: 10%, 180℃: 5%), since hydrogen was subtracted from the reaction field, accelerating methanol decomposition even at given lower temperatures. Methanol conversion may be further increased by pressurizing the reactor.