A new method for evaluating the sewage sludge pyrolysis kinetics

A new method to simplify calculation the kinetics model is applied to sewage sludge pyrolysis based on the assumption that volatile run out as soon as it formed and during temperature arising process in this study. Difference method widely used to solve math problems is conducted to calculate kinetics parameters. Pyrolysis experiments are carried out at heating rates 0110, 15, 20, and 50 degrees C/min. All the TG curves are divided into three parts which are beginning decomposition temperature range, main decomposition temperature range, and final decomposition temperature range. The second one is employed to determine the parameters for more than 70% of the total mass loss occurs in this range. According to the developed method, the react order, reaction energy and pre-exponential factor are obtained, which are in the range of 3.9-4.1, 82.3-109.2 kJ/mol and 7.7 x 10(6)-2.8 x 10(9)/min, respectively, which are in the range of that reported previously. As a comparison experimental data with calculated data, the well fitting results indicate that this method is appropriate for simulating sludge pyrolysis kinetics. (C) 2009 Elsevier Ltd. All rights reserved.