Kinetic Study of Co-Pyrolysis of Lignocellulosic Biomass and Plastic Based on Fraser-Suzuki Deconvolution Procedure

Co-pyrolysis of biomass and plastics is a promising way to produce high-quality liquid fuel, and the knowledge on its kinetic and thermodynamic behaviors is crucial for designing an efficient reactor system. In this study, kinetic triplets and major thermodynamic parameters of both non-catalytic and catalytic co-pyrolysis of pine wood and high-density polyethylene (HDPE) were evaluated. Due to the complexity of co-pyrolysis process, Fraser-Suzuki function was adopted to deconvolute the derivative thermogravimetric (DTG) curves into four pseudo-components; namely pseudo- cellulose, hemicellulose, lignin and HDPE. For non-catalytic co-pyrolysis, average apparent activation energy of pseudo-hemicellulose, cellulose, lignin and HDPE were 137.12, 166.81, 227.2, 246.56 kJ/mol, respectively. The presence of HZSM-5 decreased both activation energy and pre-exponential factor and affected reaction mechanisms of each component. The activation energy of HDPE decreased by about 35% after addition of catalyst. The change of entropy (∆S) results indicated that thermal degradation process of lignin is complex, and the degradation process of HDPE evolved from dis-ordered state to ordered state after addition of catalyst. Results obtained in this work are expected to provide more precise fundamental information for further scale-up of co-pyrolysis process