Conceptual Design of Ethylene Oxide Production Process with Integrated Conversion of Waste CO2 Stream

Carbon dioxide (CO2) is widely known to be one of the most redundant gaseous waste streams. The
conversion of CO2 into fuels and chemicals is a promising pathway for dealing with waste CO2 and
more sustainable chemicals manufacturing. Nevertheless, examples of the process on an industrially
relevant scale are still missing. One of the obstacles limiting the process application are additional
up & downstream costs related to obtaining pure CO2 and separation of the reaction products.
Hence, this paper analyses the case of integration of CO2 electroreduction (CO2RR) into a
manufacturing process in which those two key barriers can be omitted: ethylene oxide (EO)
production. EO is one of most widely used bulk chemicals and the process variant mostly applied in
the industry generates significant amounts of waste CO2 as reaction by-product. The waste CO2 is
separated from gas stream and removed to avoid compound build-up, hence the substrate for
electroreduction is available at no additional cost. CO2 can be converted into an ethylene-rich stream
and recycled back to the EO reactor, which uses ethylene as raw material. Further, no complex
separations are required, as other key electroreduction product (CH4) is also used in EO production
reactors. Overall, integration of CO2 electroreduction into EO manufacturing enables to reduce waste
generation and significantly increase process mass efficiency. To highlight the great potential of such
process integration, the conceptual process design is presented and the potential for economic
savings is quantified.