Intrinsic kinetics of CO2 gasification of a Victorian coal char

Abstract

CO2 gasification of Victorian (Morwell) brown coal char was studied using a thermogravimetric analyser (TG). Gasification kinetics of demineralised, Ca-loaded, and Fe-loaded Morwell char were also studied. The grain model and random pore model were used to fit the gasification data. The random pore model fitted the experimental data better than the grain model. The activation energy was 189.05 kJ mol−1 for the CO2 gasification of Morwell coal char. With 2 % Ca loading, the activation energy increased to 204.53 kJ mol−1 due to lowering of the surface area. However, an order of magnitude increase in the pre-exponential factor indicated an increase in active reaction sites for the 2 % Ca-loaded sample, resulting in a net increase in gasification rate. 5 % Ca loading and 2 % Fe loading proved to be less effective in increasing the gasification rate. Analysis of the TG outlet gas also proved the effectiveness of 2 % Ca loading as a gasification catalyst.