Products Distribution and Reaction Kinetics From Co-Pyrolysis of Pinewood and Polypropylene Under Non-Catalytic and Catalytic Reaction Conditions

Co-pyrolysis technology offers vital pathways for the efficient utilization of plastics and biomass resources to help reduce environmental problems and energy resource issues. The pyrolysis characteristics of pinewood and polypropylene (PP) mixtures were analyzed using thermogravimetric analysis. The results showed a decrease in the first peak of the mixture with an increase in PP in the mixture, while the second peak increased with an increase in PP in the mixture. The addition of a catalyst decreased the DTG peak heights. The reduction in the first peak with different catalysts was in the order: CaO/ZSM-5 > CaO > ZSM-5, while the second peak showed: CaO > CaO/ZSM-5 > ZSM-5. The activation energy, calculated by Flynn–Wall–Ozawa, Kissinger–Akahira–Sunose, and Friedman models, revealed that ZSM-5 reduced the activation energy, whereas CaO/ZSM-5 increased the activation energy, as compared to no catalyst case. Increase of co-pyrolysis temperature reduced the yield of aldehydes, ketones, acids, and esters, but increased the yield of hydrocarbons. The addition of CaO reduced the yield of ketones, phenols, esters, and acids, while it increased the yield of alcohols. The addition of ZSM-5 also decreased the yield of ketones, phenols, acids, and hydrocarbons, but increased the yield of furans and alcohols. The addition of CaO/ZSM-5 specifically reduced the yield of aldehydes and alcohols. The results show the important role of the specific catalysts examined on the resulting products distribution for the same reaction condition.