Thermal behavior, kinetics and gas evolution characteristics for the co-pyrolysis of real-world plastic and tyre wastes

Investigations into the co-pyrolysis of four kinds of real-world plastics (high-density polyethylene (HDPE), low-density polyethylene (LDPE), polypropylene (PP), and polystyrene (PS)) and tyre were carried out in a TG-FTIR instrument. The thermal decomposition behavior, conversion kinetics and gas releasing properties during co-pyrolysis process were investigated. It was found that co-pyrolysis of plastics and tyre delayed the pyrolysis process with a wider decomposition temperature range, when compared with the pyrolysis of individual plastic. The kinetic analysis results indicated that the co-pyrolysis process could be divided into three stages by a single first-order reaction model with the activation energies of 65-87, 34-92, and 138-208 kJ/mol, respectively. A positive synergistic interaction was found between PS and tyre, while the co-pyrolysis of PP/HDPE/LDPE and tyre was negatively influenced. During co-pyrolysis of tyre with four kinds of plastics, CH4 was the majority product for HDPE, LDPE and PP, whereas for PS, the aromatics and C-H containing compounds were the main products. The results regarding co-pyrolysis of plastics and tyres provide an insight into an environmentally friendly recycling technology for polymeric wastes. (C) 2020 Elsevier Ltd. All rights reserved.