Abstract

Low-density polyethylene (LDPE) and high-density polyethylene (HDPE) are some of the most commonly used materials worldwide. These polymers are typically produced through the polymerization of ethylene which is conventionally produced through the energy-intensive steam cracking of naphtha or ethane. However, the conventional production process for LDPE and HDPE results in significant greenhouse gas emissions (1.92 and 1.86 kg CO2/kg of polymer, respectively).
Hence, this work focuses on the design of alternative pathways based on CO2 capture and utilization (CCU) for polymer production. The proposed pathways for CCU-polymers are based on the conversion of CO2 to methanol, followed by the methanol-to-olefins (MTO) process to produce mainly ethylene, and consequently LDPE and HDPE from ethylene. The process design and simulation of the entire pathway are conducted in AspenPlus, while the life cycle assessment (LCA) is done through OpenLCA.
The LCA results showed that the CCU-MTO pathway is an environmentally attractive option, particularly in regions where renewable (low-carbon) electricity is more prominent, such as Quebec and Ontario, where negative CO2 emissions are achieved. This makes polymer production via the proposed method suitable for the permanent mitigation of CO2.