Synergistic effects of catalytic co-pyrolysis of corn cob and HDPE waste mixtures using weight average global process model

Abstract

Synergistic effects and kinetic parameters for binary mixtures of corn cob and high-density polyethylene (HDPE) in co-pyrolysis with the presence of renewable chicken and duck eggshell catalyst are evaluated using thermogravimetric analysis (TGA) approach at various heating rates (10–200 K/min) in temperature range of 323–1173 K. Weight average global process model based on two-stage kinetic scheme are employed in this study. The reaction mechanisms involved in the co-pyrolysis process are 1-D diffusion for second stage of thermal degradation and 3-D diffusion for third stage of the thermal degradation. The difference in the experimental and estimated values of the catalytic corn cob and HDPE mixtures in terms of weight loss indicates the existence of the synergistic effects during the pyrolysis process. The values of the activation energy for pure corn cob, pure HDPE, binary mixtures of corn cob and HDPE are reported in the range of 43.61–83.03, 412.32–510.72, and 28.98–93.18 kJ/mol, respectively. Meanwhile, the activation energy for catalytic pyrolysis process are in the range of 28.98–113.17 and 23.65–119.50 kJ/mol respectively in the presence of chicken and duck eggshells as catalyst. Additionally, artificial neural network (ANN) and joint optimization modelling are also utilized to validate and optimize the results from the TGA.