Gases production from microwave-assisted pyrolysis of polypropylene plastic

Abstract

Polypropylene (PP) is widely used around the world, but PP waste has caused environmental problems after being abandoned. To deal with this massive PP waste, pyrolysis is one of the potential technologies appropriate for PP final utilization. Microwave assisted heating was adopted in this study to investigate the effects of pyrolysis temperatures from: 700, 750, 800, 850 and 900 ℃; microwave power set at: 600, 700, 800, 900 and 1000 Watts; and SiC/PP mass ratios of: 60:5, 60:10, 60:15, 60:20 and 60:25. Results for the above range of operating conditions were recorded for: product gas yields, pyrolytic gas transient compositions, and product gas heating values (HHVs). The transient product gases included C3H6, CH4 and H2 with stable concentrations ranging from 7.5 to 22.1 vol%, 5.1–20.2 vol% and 5.4–21.1 vol%, respectively. The optimal gas yield of 70.7 wt% was obtained when the pyrolysis temperature, microwave power, and mass ratio were 900 ℃, 1000 Watts, and 60:15, respectively. Based on the gas components, the corresponding HHVs ranged from 13.9 to 34.4 MJ/Nm3.