K2CO3-Catalyzed CO2 Gasification of Ash-Free Coal: Kinetic Study

Abstract

The kinetics of K2CO3-catalyzed CO2 gasification of ash-free coal was investigated with a thermogravimetric analyzer and compared to raw coal and uncatalyzed ash-free coal. At 750 °C, the gasification of ash-free coal dry mixed with 20 wt % K2CO3 was approximately 3 and 60 times faster than the raw coal and ash-free coal without catalyst, respectively. Increasing the amount of catalyst from 20 to 45 wt % increased the gasification rate 3-fold. The gasification rate of ash-free coal containing potassium catalyst strongly depended upon the pretreatment (i.e., heating gas atmosphere and heating time) because it directly affected the degree of catalyst reduction. The catalytic gasification behavior could only be predicted with the extended random pore model, whereas the random pore model and integrated model were essentially equal for fitting the gasification rate for raw and ash-free coal. The activation energy for the catalyzed ash-free coal gasification was approximately 100 kJ mol–1 larger than for raw co...