Ethylene is recognized as one of the most significant chemicals globally.1 The projected ethylene production for 2023 stands at 227.6 million tonnes, with expectations of continued demand growth. The primary use of ethylene, accounting for over 76%, lies in the production of plastics such as polyethylene, polyvinyl chloride, and polystyrene.2 Despite the enduring carbon retention potential of plastics themselves, traditional ethylene feedstock production from fossil resources contributes substantially to greenhouse gas emissions, ranging from 0.29 to 2.29 kgCO2/kgEthylene depending on various factors like feedstock and process design.3–5 Various decarbonization strategies, including the utilization of hydrogen as a primary heat source, have been proposed to reduce the carbon footprint of ethylene production,6 but their efficacy remains limited, offering at best a 0–30% reduction in on-site CO2 emissions.5
Looking ahead to a future abundant in renewable energy, there's potential for refineries to transition from conventional thermochemical methods to electrochemical synthesis routes. Proton-conducting high-temperature membranes to produce ethylene from ethane,7 and the oxidative coupling of methane (OCM) in solid oxide cells have emerged as promising alternatives. OCM presents a particularly groundbreaking opportunity as it allows for the upgrading of simple organic molecules like methane; and as such, the utilization of methane from biogenic sources, thereby reducing reliance on fossil resources and mitigating emissions from ethane feedstock production. However, despite these promising developments, there's a significant gap in our understanding of the performance, costs, and competitive advantages associated with practical electrochemical system implementations.
Recent advancements in electrochemical OCM,8,9 including demonstrations with metal-supported cells10, indicate progress towards enhancing flexibility in operating conditions and system integration. To accelerate and better guide solid oxide OCM cell development, a comprehensive system-level analysis is conducted to evaluate the potential implications of operating conditions on both performance and economics in prospective OCM-based ethylene refineries. This work builds upon previous work by the authors11 and further investigates possibilities of H2 co-production and CO2 utilization.
}, year = {2024}, month = {06/2024}, issn = {LBNL-2001597}, language = {eng}, }