Improvement of biomass char-CO2 gasification reactivity using microwave irradiation and natural catalyst

Abstract In char-CO 2 gasification, the highly endothermic nature of the Boudouard reaction (CO 2 (g) + C (s) ↔ 2CO (g)) dictates use of very high temperatures to shift the equilibrium towards CO production. In this study, such high temperature (750–900 °C) was provided by microwave irradiation. A microwave heating system was developed to perform the gasification tests by passing CO 2 through a packed bed of oil palm shell (OPS) char. In order to speed up the microwave-induced CO 2 gasification, ash of palm empty fruit bunch (EFB) was used as natural catalyst (rich in potassium) and incorporated into the skeleton of the OPS char. The synergistic effect of microwave and catalyst concluded to very encouraging results, where a CO 2 conversion of 93% was achieved at 900 °C, within 60 min microwave gasification. In comparison, CO 2 conversion in thermal gasification (conventional heating) of pristine OPS char was only 58% under the same operating condition.