Integrated Assessment of Waste Tire Pyrolysis and Upgrading Pathways for Production of High-Value Products.

Waste tire pyrolysis has received increasing attention as a promising technology recently due to the shortage of fossil resources and the severity of environmental impact. In this study, the process of waste tire pyrolysis and upgrading to obtain high-value products was simulated by Aspen Plus. Also, based on life cycle assessment, the indexes of energy, environmental, economic, and comprehensive performance were proposed to evaluate different high-value pathways. Results demonstrate that the integrated system of waste tire pyrolysis, pyrolytic oil (TPO) refining, and pyrolytic carbon black (CBp) modification has higher energy efficiency than the independent system of TPO refining, with an improvement rate of 2.6%. Meanwhile, the resource-environmental performance of the integrated system is better. However, combined with the economic benefit, the independent system is more comprehensively beneficial, with the index of comprehensive performance (BEECR) of 0.94, which increases by 3.3% compared with the integrated system. Furthermore, the comparisons of different improved high-value paths based on the independent system as the benchmark indicate that the pathway of promoting sulfur conversion during pyrolysis to reduce the sulfur content in TPO can increase the BEECR from 0.94 to 1.064, with the growth of 13.2%. Also, the physical modification of CBp to reduce the production cost and environmental impact has better performance of BEECR, increasing by 20.2%. The final sensitivity analyses show that the combined improved high-value case established by the abovementioned two paths can achieve a favorable benefit in a wide range of crude oil and waste tire prices and the environmental tax.