Coal: Kinetic analysis of thermogravimetric data

Abstract

Thermogravimetry, TG, is widely used to investigate rate processes. This method involves the continuous measurement of the change in mass or rate of mass loss, DTG, of a sample with temperature (or time). Such data has been used to determine kinetic parameters, such as activation energy and order of reaction. A number of methods have been developed in the literature to permit kinetic analysis of TG data. The kinetic parameters for the decomposition of coal are frequently calculated from one TG curve obtained at a constant heating rate. Since kinetic parameters are influenced by the heating rate, methods involving one thermogram have been criticized on the basis that they may give incorrect values for the activation energy and reaction order, and that only methods involving multiple heating rates will give reliable results. In this work, comparison is made of four methods for analyzing TG data of a sub-bituminous coal.