Abstract
Electrochemical reduction of CO2 (eCO2RR) is a potential pathway for the defossilization of the process industry, offering the possibility of using captured carbon to produce a wide variety of green chemicals, such as CO, formic acid, acetic acid and ethanol, while simultaneously electrifying the chemical industry. However, liquid products from eCO2RR still face major challenges with respect to the downstream processing due to their high dilution in aqueous streams, the presence of electrolytes, and the formation of pinch points and azeotropes. This work investigates the integration of a CO2 electrolysis setup producing acetic acid at high selectivity with the downstream processing section. The process has been simulated in Aspen Plus with particular emphasis on the integration of electrolyzer waste heat via heat pumps and the recovery and recycling of electrolytes using established separation technologies. In contrast to commonly proposed approaches based on electrochemical separation methods, this work focuses on technically mature unit operations to enable a more realistic assessment of process feasibility. Under renewable electricity supply and heat pump integration, the process achieves an emission intensity of approximately 156 gCO2eq/kgAA, substantially below the conventional fossil-based production pathway. Nevertheless, the techno-economic assessment yields a net present value of about -670 M$ over a 20-year lifetime and a levelized cost of acetic acid of ~1520 $/t more than twice the current market price of approximately 760 $/t. The process is therefore not yet economically competitive under current electrolyzer cost assumptions, while identifying electrolyzer performance and electricity costs as the primary drivers for future improvement.