Gasification Rate of Various Biomass Feedstocks in Supercritical Water

Supercritical water gasification is expected to be an effective gasification process for wet biomass, but its reaction kinetics has not been elucidated for actual biomass feedstocks. In this study, seven biomass species are gasified in a supercritical water gasification reactor with and without use of a suspended activated carbon catalyst, and the overall gasification rates are determined. The feedstocks can be classified into three groups depending on the gasification characteristics. Representative gasification-rate parameters are presented. The homogeneous reaction had a pre-exponential factor of 50.0 s(-1) and an activation energy of 67.9 kJ/mol. The heterogeneous reaction for feedstocks with high cellulose content had a pre-exponential factor of 4.87 x 10(9) s(-1) and an activation energy of 161 kJ/mol, while, feedstocks with low cellulose content had a pre-exponential factor of 1.91 x 10(4) s(-1) and an activation energy of 84.2 kJ/mol.