Thermal and kinetic characteristics of the catalytic effect of different catalysts on the combustion of coal-char blends

Abstract

Thermal and kinetic characteristics of the catalytic effect of CaO/MnO2/Fe2O3 on the combustion of coal-char blends were investigated with thermogravimetric analysis. Different characteristic parameters obtained from TG-DTG curves were used to determine the combustion characteristic of samples. A sectioning method was adopted to study the kinetics at the stage I and II of samples combustion. The kinetic parameters of samples were also determined according to the Coats-Redfern method. The experimental results indicated that, in stage I, the catalysts promoted volatile matter release and combustion decreased the ignition temperature; in stage II, the catalysts accelerated the combustion of fixed carbon in char. The ignition properties and the combustion properties all increased with catalysts addition. Fe2O3 and CaO exhibited effective catalytic effect on reducing the activation energy in the stage I and II of coal-char blends combustion. The catalytic effect of MnO2 in the stage II was not obvious. Therefore, Fe2O3 and CaO were considered having more catalytically active than MnO2 in coal-char blends combustion. [Received: May 30, 2018; Accepted: December 17, 2018]