Catalytic Effect of Metallic Oxides on Combustion Behavior of High Ash Coal

Abstract

By means of thermogravimetric analysis, the catalytic effect of metallic oxides (CuO, Fe2O3, and ZnO) on the combustion behavior of high-ash coal was investigated under nonisothermal conditions. Experiments were conducted from ambient temperature to 1000 °C at a heating rate of 20 °C·min-1. The ignition temperature, burnout performance, and exothermic behavior were used to evaluate the catalytic effect. Moreover, the kinetics parameters (activation energy and pre-exponential factor) were determined using the Coats−Redfern method. It is indicated that, compared with the combustion characteristics of high-ash coal, the ignition temperature of the samples with metallic oxides decreases by 8−50 °C. Metallic oxides can speed up the combustion rate and burnout of the fixed carbon. The exothermic values of samples incorporating metallic oxides increase by 15−30%, which may be due to the catalytic effect of metallic oxides on fixed carbon combustion. The activation energies of the samples decrease, and there is a linear connection between the activation energies and pre-exponential factors (ln A = 0.2683 × E-12.807).