Kinetic study for the co-pyrolysis of lignocellulosic biomass and plastics using the distributed activation energy model

The characteristics of bio-oil produced from biomass pyrolysis can be improved by co-feeding waste materials. In this work, co-pyrolysis of lignocellulosic biomass with six different waste plastics (waste tyre (WT), polylactic acid (PLA), polystyrene (PS), polyethylene terephthalate (PET), polypropylene (PP) and high density polyethylene (HDPE)) were conducted in a thermogravimetric analyser to study thermal decomposition of the mixtures. The distributed activation energy model (DAEM) was applied to pure feedstocks at 5 and 10 °C/min heating rates to fit the kinetic parameters. The model was used to simulate the co-pyrolysis of biomass/plastic mixtures assuming additive effect of components at different weight proportions and heating rates. Profiles of the fraction of mass remaining for mixtures at 100 °C/min were reproduced with a remarkable agreement. Discrepancies between the experimental and calculated profiles were considered as a measure of the extent of interactions occurring in the co-pyrolysis. Projections of the behaviour of mixtures under flash pyrolysis conditions were performed to study important aspects of the process, such as radical interactions and optimum working temperature.