Modeling Pyrolysis of Charring Materials: Determining Kinetic Properties and Heat of Pyrolysis of Medium Density Fiberboard

For modeling the burning behavior of medium density fiberboard (MDF), pyrolysis kinetics was experimentally investigated through simultaneous differential scanning calorimetry and thermogravimetric analysis (SDT) experiments. Three decomposition models with up to four pyrolyzing components (phenol-formaldehyde (PF) resin, hemicellulose, cellulose, and lignin) were used to model the pyrolysis process. Genetic algorithm (GA) was applied to produce the kinetic properties based on the experimental thermogravimetric (TG) curves. On the other hand, the heat of pyrolysis was determined from the differential scanning calorimetry (DSC) measurements. The kinetic properties determined by the genetic algorithm are found to be consistent with those from other sources within the literature. Unlike natural biomass materials with only one endothermic peak, MDF presents two noticeable endothermic peaks from the DSC results. This shows two apparent endothermic regions during the pyrolysis process. A combined analysis of the DSC curves and the decomposition model demonstrates that the first endothermic region is mainly caused by the pyrolysis of PF resin which is also influenced by the exothermic reaction of hemicellulose pyrolysis. As a result, the first endothermic region has a higher heat of pyrolysis, 530 kJ/kg, compared to the second endothermic region, 150 kJ/kg. The second endothermic region is mainly caused by the cellulose pyrolysis.