Investigations on carbonization processes of plain tobacco stems and HPO-impregnated tobacco stems used for the preparation of activated carbons with HPO activation

摘要

In order to elucidate the mechanism of carbonization process of tobacco stems-based activated carbons with HPO-activation, the pyrolysis characteristics of plain tobacco stems and HPO-impregnated tobacco stems were investigated through thermogravimetry (TG) at different heating rates (5, 15, 30K/min) under nitrogen atmosphere. Based on TG curves, the kinetic parameters of the processes, including pre-exponential factors and activation energies, were calculated using the method of Coats-Redfern. The pyrolytic kinetic models of plain tobacco stems and HPO-impregnated tobacco stems were set up. The main pyrolysis stage could be described by the first-order and 2.5-order global models for plain tobacco stems and HPO-impregnated tobacco stems, respectively. The results indicated that the activation energy of carbonization process of HPO-impregnated tobacco stems was lower about 32.67-38.71kJmolp# than that of plain tobacco stems; furthermore, the kinetic parameters exhibited kinetic compensation effects.