Experimental study on pore structure and apparent kinetic parameters of char combustion in kinetics-controlled regime

Pore structure has a critical role during the combustion process of char particles. The pore structures of six char samples were tested by both gas adsorption and mercury porosimetry. The pore distribution dimensions were obtained, which were observed to be related to the fractal dimension of pore structures. To study the intrinsic reactivity of char samples, the char samples were also burned in a thermogravinietric analyzer. The ramp heating rates were devised at 5, 10, 15, 20, and 25 K/min, so that the char samples were burned in the kinetic regime. The so-called "isoconversional method" was used to investigate the apparent kinetic parameters. The results show that the apparent activation energies of the six char samples share almost the same value: 150 kJ/mol. Two exponents in the deduced model function are determined, relative to the pore distribution dimensions. The model function reveals the relationship between the initial pore structure and the evolution of pore surface area during the combustion of char particles in the kinetic regime.