Kinetic analysis of CO2 gasification of corn straw

Abstract

CO2 gasification of biomass is a prospective method to achieve carbon neutrality. Currently, most of the attention is focused on the study of the pyrolysis of biomass or the CO2 gasification of biochar, while the exploration of the whole reaction process and the relationship between the pyrolysis stage and gasification stage are neglected. In this paper, the kinetic analysis of the whole CO2 gasification process of corn straw was investigated with Thermogravimetric and Fourier transform infrared spectroscopy analysis. The results illustrated that the entire CO2 gasification process of corn straw was divided into two major stages, the biomass pyrolysis stage and the biochar gasification stage, at 618 °C. Average activation energy determined by FWO and KAS methods were 180.82 and 180.42 kJ/mol at the pyrolysis stage, and 239.43 and 232.82 kJ/mol at the biochar gasification stage. The pyrolysis of corn straw is a multi-stage process followed three reaction mechanisms, diffusional, nucleation and order-based model. The reaction mechanism of the char gasification stage is consistent with the F1 and D2 models. The study was useful for developing an industrial reactor for the CO2 gasification of corn straw.