Life cycle environment and direct operating cost assessment of coal to polyolefin integrated with coke oven gas, membrane separation and CO2 utilization

Coal to polyolefin (CTP) is an important route for polyolefin in China, but its manufacturing process is associated with serious environmental issues. In this study, life cycle assessment (LCA) coupled with direct operating cost analysis methods were employed to compare the CTP route with petroleum, biomass, and waste plastic polyolefin production routes. On the basis, Dual gas feed (coal gas with coke oven gas, CTP-DGF), heat exchanger network optimization (CTP-HEN), externally and internally coupled membrane distillation (CTP-EMEM, CTP-MEM) and CO 2 utilization (CTP-CCU) technologies were respectively proposed and evaluated to improve the performance of traditional CTP route. Finally, the optimal integrated route (CTP-INT) was established from CTP-DGF, CTP-MEM and CTP-CCU. The results indicated that, CTP showed the highest environmental impacts, in which coal gasification and methanol to polyolefin units were the main contributors. Among the five optimization technologies, CTP-DGF exhibits the optimal environmental performance. Compared with CTP, CTP-INT reduced the global warming potential and direct operating cost by 49.7% and 19.0%. In the future, the environmental impact of CTP-INT route could be reduced by 50.0% considering the low-carbon power grid. This study aims to provide practical insights into improving the cradle-to-gate environmental and direct operating-cost performance of the CTP route.