A study on the applicability of kinetic models for Shenfu coal char gasification with CO 2 at elevated temperatures

Abstract

In this paper, measurements of the CO 2 gasification kinetics for two types of Shenfu coal chars, which were respectively prepared by slow and rapid pyrolysis at temperatures of 950 ° C and 1,400 ° C, were performed by an isothermal thermo-gravimetric analysis under ambient pressure and elevated temperature conditions. Simultaneously, the applicability of the kinetic model for the CO 2 gasification reaction of Shenfu coal chars was discussed. The results showed: (i) the shrinking un-reacted core model was not appropriate to describe the gasification reaction process of Shenfu coal chars with CO 2 in the whole experimental temperature range; (ii) at the relatively low temperatures, the modified volumetric model was as good as the random pore model to simulate the CO 2 gasification reaction of Shenfu coal chars, while at the elevated temperatures, the modified volumetric model was superior to the random pore model for this process; (iii) the integral expression of the modified volumetric model was more favorable than the differential expression of that for fitting the experimental data. Moreover, by simply introducing a function: A = A*exp(ft), it was found that the extensive model of the modified volumetric model could make much better predictions than the modified volumetric model. It was recommended as a convenient empirical model for comprehensive simulation of Shenfu coal char gasification with under conditions close to those of entrained flow gasification.