Investigation on catalyzed combustion of high ash coal by thermogravimetric analysis

Thermogravimetric analysis (TGA) has been used to obtain information on ignition and burnout characteristics of high ash coal (Ab. HAC) incorporating Fe2O3, MnO2 and BaCO3. Experiments were conducted from the ambient temperature to 1273 K at a heating rate of 20 K min(-1). Ignition index and burnout index had been put forward to describe further the ignition and burnout characteristics. It was indicated that compared with those of HAC, the relative active sequence of catalysts to the ignition characteristics could be described as follows: MnO2 > BaCO3 > Fe2O3; the relative active sequence of catalysts to the burnout could be described as follows: Fe2O3 > BaCO3 > MnO2. Catalyzed combustion mechanisms of the coal samples were also discussed. It was also demonstrated that the catalysis of the catalysts to the HAC combustion was embodied in the enhancement of the emission of volatile matters (VM) from HAC, which reduces the ignition temperature. Another role of the catalysts to the combustion of HAC could be a carrier of oxygen that impromotes the oxygen transfer to the char of HAC. (c) 2006 Elsevier B.V. All rights reserved.