Resource and environmental assessment of pyrolysis-based high-value utilization of waste passenger tires

Carbon black and fuel oil as the products of conventional pyrolysis are limited in application owing to their low quality. This paper presents a pyrolysis-based high-value utilization process of waste passenger tires (WPTs). A comparison of the life cycle assessment (LCA) between this process and a conventional pyrolysis process was carried out. Moreover, a comprehensive evaluation index of the ratio of economic profit to environmental cost (PCR) was established. The results show that the increase in economic profits brought about by the high-value utilization process is higher than the increase in environmental costs, and the pyrolysis-based high-value utilization of WPTs has more positive benefits than conventional pyrolysis. Reducing the consumption of electricity and natural gas in the high-value utilization process has a significant effect on the decline of the main environmental impacts. Compared with the production of conventional pyrolytic products, this has the dual advantages of resource saving and environmental protection. Also, the environmental loads of ozone layer depletion (ODP) and human toxicity (HTP) are reduced by over 90%, and the loads of abiotic depletion (ADP) of minerals and fossil fuels are reduced by over 84%. Sensitivity analyses show that both the production cost and the price of carbon black significantly influence the PCR. The replacement of coal-fired power generation with renewable energy generation has a positive effect on improving the resource and environmental performance for the high-value utilization process of WPTs.