  Electrochemical conversion of CO2 (CO2R) into fuels and chemicals can both
reduce CO2 emissions and allow for clean manufacturing in the scenario of
significant expansion of renewable power generation. However, large-scale
process deployment is currently limited by unfavourable process economics
resulting from significant up- and down-stream costs for obtaining pure CO2,
separation of reaction products and increased logistical effort. We have
discovered a method for economically viable recycling of waste CO2 that
addresses these challenges. Our approach is based on integration of a CO2R unit
into an existing manufacturing process: ethylene oxide (EO) production, which
emits CO2 as a by-product. The standard EO process separates waste CO2 from gas
stream, hence the substrate for electroreduction is available at an EO plant at
no additional cost. CO2 can be converted into an ethylene-rich stream and
recycled on-site back to the EO reactor, which uses ethylene as a raw material,
and also the anode product (oxygen) can be simultaneously valorized for the EO
production reaction. If powered by a renewable electricity source, the process
will significantly (ca. 80%) reduce the CO2 emissions of an EO manufacturing
plant. A sensitivity analysis shows that the recycling approach can be
economically viable in the short term and that its payback time could be as low
as 1-2 years in the regions with higher carbon taxes and/or with access to
low-cost electricity sources.
