This work focuses on the design and analysis of innovative environmentally friendly pathways to produce low-density polyethylene and high-density polyethylene, as the main feedstock of petrochemical industries, based on CO2 capture and utilization. For each polymer, the process development and simulation of the proposed pathways are performed using Aspen Plus. Each pathway includes the following units: CO2 capture from flue gas, hydrogen production via electrolysis of water, methanol production, olefin production, and polymerization of ethylene. Moreover, the greenhouse gas emissions of the proposed pathways are compared to those of the conventional method i.e., steam cracking. The midpoint and endpoint lifecycle assessment of each pathway are conducted using TRACI 2.1 and ReCiPe Endpoint (H, A) lifecycle impact assessment methods in the OpenLCA software, respectively, for various geographical locations, electricity sources and assessment scenarios for the incorporation of the by-products. The lifecycle assessment results show that the new pathway is an environmentally attractive option, particularly in regions where renewable (low-carbon) electricity is more prominent, such as Quebec and Ontario provinces in Canada. In such regions, negative CO2 emissions, as low as −6.1 kg CO2eq/kg polymer, can be achieved. However, in locations where coal or natural gas are the main sources of electricity generation, such as Alberta, lifecycle emissions increase to 20 times the emissions of the conventional method. Furthermore, the impact of incorporating alternative methanol production processes is evaluated. Results show that using the tri-reforming of methane as an effective syngas production technology from CO2 and natural gas can reduce the lifecycle greenhouse gas emissions by up to 94% and 62%, compared to the conventional high- and low-density polyethylene production pathways.

这项工作的重点是基于 CO2 捕获和利用的创新环保途径的设计和分析，以生产低密度聚乙烯和高密度聚乙烯，作为石化工业的主要原料。对于每种聚合物，所提出途径的工艺开发和模拟都是使用 Aspen Plus 进行的。每个途径包括以下单元：从烟气中捕获 CO2、通过电解水生产氢气、甲醇生产、烯烃生产和乙烯聚合。此外，将拟议途径的温室气体排放量与传统方法（即蒸汽裂解）的温室气体排放量进行了比较。使用 TRACI 2.1 和 ReCiPe Endpoint (H, a) OpenLCA 软件中的生命周期影响评估方法，分别针对各种地理位置、电力来源和副产品并入的评估场景。生命周期评估结果表明，新途径是一种对环境有吸引力的选择，特别是在可再生（低碳）电力更为突出的地区，例如加拿大的魁北克省和安大略省。在这些地区，可以实现低至 −6.1 kg CO2eq/kg 聚合物的负 CO2 排放。然而，在以煤炭或天然气为主要发电来源的地区，例如艾伯塔省，生命周期排放量增加到传统方法排放量的 20 倍。此外，还评估了采用替代甲醇生产工艺的影响。