Electrochemical conversion of carbon dioxide to ethylene: Plant design, evaluation and prospects for the future

Abstract

In support of the energy and feedstock transition, new concepts of producing chemical building blocks are necessary. While currently ethylene is mainly produced from fossil feedstocks, this paper explores its production via the electrochemical conversion of CO2. Different process routes were reviewed and a most promising route was selected based on Faradaic efficiency, current density, overpotential, and material availability. In this preferred route, syngas is produced electrochemically from CO2, which is then converted into methanol before the final conversion into ethylene and other high-value chemicals. On this preferred route, a design has been made which includes process design, unit design and a techno-economic evaluation, with CAPEX and OPEX included. Also the CO2 emission is evaluated and it was found that a net consumption of 2.5 ton CO2 per ton high-value chemical can be achieved. As expected, the investment and operational costs are very high with the applied price sets. However, when the electricity price decreases due to developments in renewable energy and a tax is implemented on CO2 emissions, this process can become economically viable and can contribute to CO2 emission reduction in view of climate change.