Kinetic thermal behaviour and evaluation of physical structure of sugar cane bagasse char during non-isothermal steam gasification

In the current study, the steam gasification reactivity, thermal behaviour and activation energies of sugar cane bagasse (SCB) chars prepared at 500, 800 and 900 degrees C were investigated via thermogravimetric analyser (TGA) under non isothermal conditions at different heating rates of 10, 15 and 20 degrees C min(-1). The physical structures of SCB chars as a function of pyrolysis temperature have been studied by using Brunauer-Emmett-Teller (BET) surface area technique. The achieved results explore that the gasification of SCB chars took place almost completely in one-stage process. The char reactivity is directly proportional to gasification heating rate and inversely to the pyrolysis temperature. The pyrolysis temperature significantly affected on the physical char structures. The activation energies were estimated by Vyazovkin and Ozawa-Flynn-wall methods. The Vyazovkin and Flynn-Wall-Ozawa methods show mean activation energies of 131.20-141.61 kJ mol(-1) for SCB 5, 195.40-203.17 kJ mol(-1) for SCB 8 and 246.84-252.66 kJ mol(-1) for SCB 9. Finally, Vyazovkin and Ozawa-Flynn-Wall methods are efficiently utilized to predict the experimental data and the reaction mechanism of SCB chars steam gasification. (C) 2016 Brazilian Metallurgical, Materials and Mining Association. Published by Elsevier Editora Ltda.