ON THE KINETICS OF THERMAL-DECOMPOSITION OF WOOD AND WOOD COMPONENTS

A kinetic analysis of the thermal decomposition of eucalyptus sawdust, cellulose and eucalyptus kraft lignin has been accomplished from temperature-programmed reaction experiments, using two different approaches: the first assumes an overall reaction model, whereas in the second, pyrolysis is viewed as a process consisting of multiple reactions in parallel and a distribution of activation energies is derived. The results obtained reveal that the simple first approach, which leads to overall values of the apparent kinetic parameters allows a fairly good reproduction of the experimental curves, although in the case of wood a two-stage analysis was necessary. No improvement was noticed with the use of activation energy distribution functions resulting from the multiple reaction treatment, except for cellulose and lignin at high conversion, whereas the steep region of the weight-loss curve for cellulose is better described with the overall reaction model. © 1990.