Kinetics of CO release from bark and medium density fibreboard pyrolysis

The apparent rate of CO release during pyrolysis, from bark and Medium Density Fibreboard (MDF) particles was measured. The method used was a pre heated wire grid technique. Experiments were performed under ambient nitrogen and at atmospheric pressure conditions over a temperature range 620940 K. The temperature history of each pyrolysis experiment has been recorded. The CO release was monitored using a tunable diode laser set to a single infrared absorption line of 2082 cm-1. The release followed a typical growth curve in time to a steady state level. Curves were fitted using a simple first order kinetic analysis and Arrhenius parameters were extracted. Both uncertainties in applied temperature and release rate were taken into account. The calculated apparent activation energies Ea were 64 ± 6 kJ mol-1 for bark and 71 ± 6 kJ mol-1 for MDF, uncertainties are determined on a very conservative basis. A single apparent rate seems to be a fair description although two time scales can be identified.