Exergy analysis of glycerol steam reforming in a heat recovery reactor

Abstract

A detailed exergy analysis was performed for the steam reforming process of glycerol by means of a series of experiments in a bench scale apparatus. The reforming was conducted in a fixed bed reactor, which operated in heat recovery mode by extracting the demanded energy from hot exhaust gases provided by a diesel engine. In order to determine the role of the main operational parameters into the exergy efficiency of the studied process, the experiments were carried out with glycerol feed concentrations in water ranging from 10% up to 90% weight, whereas the outlet reactor temperature was varied from 600 °C up to 800 °C. Detailed exergy balances revealed a compromise between the exergy destruction within the reforming reactor and liquid separator versus the exergy losses associated to the tar and char outputs. This trade-off was favourable to the 50% and 70% glycerol feed concentration regimes and plateaus of about 74% exergy efficiency and 24 MJ/kg dry syngas exergy content were verified from 650 to 800 °C reactor temperatures.