Pitch pyrolysis kinetics from single TG curve

Global pitch pyrolysis kinetic parameters determined by different methods from single thermogravimetric curves are compared. Differential (Freeman-Carroll, Vachuska-Voboril), integral (Coats-Redfern, Horowitz-Metzger) and the method of direct non-linear regression (NLR) were used. Direct non-linear regression is the most suitable when the whole kinetic triplet (activation energy, frequency factor and reaction order) is searched, but the results are not quite satisfactory. If the global first order kinetic of pitch pyrolysis is accepted, similar values of activation energy and frequency factor were obtained by different methods. Considering the quality of results and applicability Coats and Redfern method is recommended in this case. (C) 2004 Elsevier B.V. All rights reserved.