Investigation on thermal conversion, kinetics and thermodynamics of coal gasification filter cake ash in oxygen fuel combustion

Abstract

Coal gasification fine ash (CGFA) has the characteristics of high carbon content, fine-grained, and large annual output, causing environmental pollution and energy wastage. Oxygen fuel combustion is an effective way to solve the CGFA problem. In this paper, the effects of thermal conversion, kinetics and thermodynamics during the oxygen-fuel combustion of CGFA are analysed. The results show that the combustion of CGFA in an oxygen-fuel atmosphere significantly improves its burn-up performance and combustion stability, but the improvement in ignition performance is not significant. an increase in oxygen concentration of more than 30% in an O2/Ar atmosphere also improves the activation energy to some extent, but the improvement in combustion performance is not significant. The average activation energy of CGFA under 30% O2/70% Ar condition is 104.25 kJ/mol, and its combustion performance is comparable to that of bituminous coal blended gasification ash at 70%. A kinetic model was developed to describe the oxygen-fuel combustion process of FCA, which can be efficiently and cleanly burned under oxygen-fuel conditions and consumed on a largescale.