Pyrolysis of coal by solid heat carrier-experimental study and kinetic modeling

Abstract

In this paper, the pyrolysis performance and pyrolysis reaction kinetic characteristic of Fuxin coal and Fushun coal using solid blast furnace slag as heat carrier were studied. Parametric studies were conducted to understand the effects of coal type, heating rate and mass ratio of slag to coal on the performance of pyrolysis reaction. The most appropriate mechanism model of coal pyrolysis reaction was selected by methods of Coats-Redfern and Malek. The results showed that the increasing heating rate was beneficial to coal pyrolysis reaction. The characteristic parameters of these two coals increased significantly with the heating rate increasing. The function of slag on coal pyrolysis reaction depended on coal type and slag to coal ratio. Slag improved pyrolysis reaction when the coalification degree was higher and heating rate was lower. Slag had no influence on pyrolysis reaction or even had restraint when the coalification degree and the heating rate showed the opposite trend. Based on the kinetic analysis, the Chemical reaction model (C3 model) was confirmed as the most appropriate mechanism model to describe the pyrolysis of coal using solid slag as heat carrier. The thermal decomposition profiles calculated using the kinetic parameters were in good agreement with the experimental results.