Analysis of gasification and tar reforming with in-situ generated char and steam

Biomass gasification has an overwhelming potential to satisfy the world’s energy needs. However, the technology is constrained by the formation of tars and the costs associated to their eradication. However, moisture, an intrinsic part of biomass, and char, a regular product from gasification, can contribute to tar removal via steam reforming. This work presents an analysis, based on numerical simulations, to elaborate a concept where the steam and char released from gasification are used to reform the produced tars. Results indicate that when the amount of moisture in wood biomass is 8% or more, at adequate temperatures (around 1073 K) the produced steam volume meets the necessary criteria for char catalytic tar reforming. On the side of char, calculations indicate that more than double the char necessary to achieve 0.5 seconds residence time in a bed is produced during each run. Moreover, it was found that moisture in biomass leads to increases in the Lower Heating Value of the produced gas and decreases in the tar contents. Based on theoretical calculations, the concept appears promising and should be subject to experimentation.

Keywords: Biomass gasification, tar reforming, auto-generated steam, syngas, char catalyst.