Non-isothermal kinetic study of bituminous coal and lignite conversion in air and in argon/air mixtures

The two isoconversional models were applied to determine the activation energy dependence on fuel samples conversion: Starink model and Ozawa iterative procedure. The mean arithmetic values of the resulted activation energy were 60 kJ/mole and 400 kJ/mole for oxidation and pyrolysis processes, respectively. These values are in good agreement with the results, presented previously for the other coals. The Starink model showed higher accuracy and lower activation energy values. The heating rate by non-isothermal oxidation and pyrolysis had the significant influence on the reaction rate because of evolution processes of the reactive surface and pore structure of the coal samples.