Activation energy distribution in pyrolysis of Thar coal, Pakistan

Abstract

Thermochemical decomposition of 16 samples of low-rank Thar coal has been investigated using nonisothermal thermogravimetric data under an inert environment. Rapid weight loss of volatiles was found in the regions of 164-233 and 473-503°C. Kinetics of pyrolysis reaction showed that the volatiles released in three consecutive steps follow first-order reaction. The kinetic evaluation focuses on all the steps to estimate activation energy, pre-exponential factor and the contribution of each step to the overall reaction. The results showed that evaporation of moisture and low-temperature volatile compounds require 3.17-4.81 kJ mol À1 activation energy. The combustion of char required a higher amount of energy (10.86-36.11 kJ mol À1). The formation of secondary char required 10.34-24.00 kJ mol À1 energy. The results suggested that Thar coal has a substantial potential for gasification due to high volatile content and low activation energy.