THERMAL-DECOMPOSITION OF WOOD IN OXIDIZING ATMOSPHERE - A KINETIC-STUDY FROM NONISOTHERMAL TG EXPERIMENTS

The kinetics of thermal decomposition of four wood species in oxygen-bearing atmospheres of 5, 10 and 20% molar O2 concentrations have been studied from temperature-programmed experiments carried out at 5, 10 and 20 K min-1 heating rate. Devolatilization as well as combustion of the reamining solid have been considered to analyze the weight loss curves. The homogeneous volume reaction (VR) model has been used to describe devolatilization, whereas for solid combustion the grain model has been also checked. A two-stage approach has been used to fit the conversion-time curves and to derive the corresponding apparent kinetic parameters. The VR/VR (pyrolysis/combustion) combination provided a better description of the experimental alpha-t curves than the VR/grain combination. Holm oak and cork oak showed very close reactivities, whereas some differences were observed for aleppo pine and eucalyptus.