Thermogravimetric Study on Co-pyrolysis of Different Rank Coals and Plastics

Abstract

China is endowed with abundant coal reserves, yet it remains heavily reliant on oil and natural gas imports. Pyrolysis of coal into gas and oil products presents a promising solution to address China’s energy security concerns. Co-pyrolysis of coal and plastic can enhance the production of liquid and gas products. Thermogravimetric experiments were conducted to explore the effects of mixing ratio, coal type (bituminous and anthracite), and plastic type (polystyrene PS and polyethylene PE) on the co-pyrolysis of coal and plastic. The results showed that the interaction during the co-pyrolysis of coal and plastic occurred mainly in the temperature interval of plastic weight loss and contributed to the increase of pyrolytic conversion. Compared to theoretical calculations, conversion rates of coal/plastic blenders co-pyrolysis can be improved mostly at blending ratios of 50% PS and 75% PE, achieving increases of 7.9–8.9% and 4.2–7.2% for PS/coal and PE/coal at 800°C respectively. The synergistic effect of coal type on co-pyrolysis is influenced by both the blending ratio and the plastic type used. So does plastic type. Finally, the kinetic analysis of co-pyrolysis was carried out. It is found different weight loss stage of co-pyrolysis processes can be expressed by first order reaction.