Kinetic studies of pyrolysis and combustion of Thar coal by thermogravimetry and chemometric data analysis

The concept of weighted mean activation energy has been used to assess the reactivity of Thar coal in terms of pyrolytic and combustion behavior using non-isothermal thermogravimetry. The samples were characterized as low sulfur and high volatile lignite to subbituminous coal. Modified Coats-Redfern method was applied to analyze the kinetic data of both processes. Thermal degradation of the samples studied was explained by three independent first-order kinetic steps. The good correlation coefficients for the independent first-order reaction models show the complexity of the overall process. The activation energy for pyrolysis reaction ranges from 19.20-63.55 to 23.68-54.49 kJ mol(-1) for combustion profile. The samples of different rank were classified applying chemometric approach on the reactivity parameters. Principal component analysis was found as a statistical tool to organize the coal samples in accordance to ASTM classification. This study broadens the scope of thermal analysis in the field of coal utilization by assessing coal reactivity.