(569fj) Modeling and Simulation of a Novel Process That Converts Waste Plastic to Ethylene

Ethylene is one of the most widely produced petrochemicals, with an estimated global output of 180 million metric tons in 2022. Currently, ethylene is primarily produced through steam cracking of ethane and naphtha, which is an energy-intensive process requiring high temperatures (>800°C) and pressures (>200 psi). Approximately 82 million metric tons of ethylene are used annually for plastic production, with the majority going to polyethylene (PE), as well as polypropylene (PP) and polyvinyl chloride (PVC). However, polymerization is also an energy-intensive process, global energy consumption is estimated to be 1.6 EJ/year for PE alone, ranking it as the third most energy-intensive chemical process. The CO₂ emissions associated with PE production are estimated to be around 14 million metric tons in 2022. Globally, it is estimated that around 70 million tons of PE are produced and consumed every year, with the majority (~79%) ending up in landfills or the environment.

In this project, a novel process is developed that utilizes waste polyethylene to produce ethylene. Preliminary experimental results indicate that it is possible to get 41% selectivity in the production of ethylene. A conceptual flowsheet based on this reactor is developed in the ASPENPlus environment. A membrane separator is utilized to separate the syn gas from ethylene, and the syn gas is sent to another reactor to produce additional ethylene. Heat integration tools are utilized to reduce the hot and cold utilities used in this process. This novel design is compared with the conventional process of making ethylene from ethane via cracking. A technoeconomic analysis is conducted to demonstrate the economic feasibility of this process. Furthermore, a life cycle analysis is conducted to demonstrate the decarbonization potential of this process.

Acknowledgment

This study was supported by the United States Department of Energy