CO₂ feedstock obtained from point sources, such as chemical industries or fossil fuel-based power plants, typically contains gaseous contaminants such as SO_x, NO_x, H₂S, and COS, which can be detrimental to the catalysts used to electrochemically convert CO₂/CO into valuable fuels and chemicals. A significant suppression of C₂₊ products is observed even in the presence of 10 ppm of these impurities due to catalyst poisoning and a selectivity change. Hence, it is necessary to have an upstream cleaning process to maintain a high selectivity toward high value C₂₊ products and to reduce the operational costs associated with frequent catalyst regeneration or replacement. We present a comprehensive process model and technoeconomic analysis of an integrated large-scale two-step CO₂/CO electroreduction plant that produces C₂₊ products including ethylene, acetic acid, ethanol, and n-propanol, using blast furnace gas obtained from a steel manufacturing facility as feedstock. Detailed modeling and integration of the upstream cleaning units, CO₂/CO electrolyzers, and the downstream separation of gas/liquid products are performed using Aspen Plus. Our analysis shows that the large-scale two-step CO₂/CO electroreduction process is not profitable under the base case scenario and requires significant improvements in electrolyzer performance, reduction in capital costs, and favorable market conditions to improve the economics. The upstream cleaning units only contribute to ∼15% of the CAPEX and ∼8% OPEX of the entire plant, while the electrolyzers contribute to ∼63% of the total CAPEX and OPEX. A positive net present value ($54M), a payback time of 13 years, and an internal rate of return of 12.8% can be achieved when the electrolyzer capital cost is $10,000/m² (−50%) and electricity price is $20/MWh (−50%), with current densities of 750 mA/cm² (+50%) for both electrolyzers and cell voltages of 2.5 V (−17%) for CO₂R and 2.0 V (−20%) for COR electrolyzers, and when the product prices are 35% higher than the current market prices. Incorporating an energy-saving coelectrolysis process or integration into facilities that can directly utilize the products can accelerate the commercialization of the two-step CO₂/CO electroreduction process.

The production of base chemicals by electrochemical conversion of captured CO₂ has the potential to close the carbon cycle, thereby contributing to a future energy transition. With the feasibility of low-temperature electrochemical CO₂ conversion demonstrated at lab scale, research is shifting toward optimizing electrolyser design and operation for industrial applications, with target values based on techno-economic analysis. However, current techno-economic analyses often neglect experimentally reported interdependencies of key performance variables such as the current density, the faradaic efficiency, and the conversion. Aiming to understand the impact of these interdependencies on the economic outlook, we develop a model capturing mass transfer effects over the channel length for an alkaline, membrane electrolyser. Coupling the channel scale with the higher level process scale and embedding this multiscale model in an economic framework allows us to analyze the economic trade-off between the performance variables. Our analysis shows that the derived target values for the performance variables strongly depend on the interdependencies described in the channel scale model. Our analysis also suggests that economically optimal current densities can be as low as half of the previously reported benchmarks. More generally, our work highlights the need to move toward multiscale models, especially in the field of CO₂ electrolysis, to effectively elucidate current bottlenecks in the quest toward economically compelling system designs.

Electrochemical reduction of CO₂using renewable energy is a promising avenue for sustainable production of bulk chemicals. However, CO₂electrolysis in aqueous systems is severely limited by mass transfer, leading to low reactor performance insufficient for industrial application. This paper shows that structured reactors operated under gas-liquid Taylor flow can overcome these limitations and significantly improve the reactor performance. This is achieved by reducing the boundary layer for mass transfer to the thin liquid film between the CO₂bubbles and the electrode. This work aims to understand the relationship between process conditions, mass transfer, and reactor performance by developing an easy-to-use analytical model. We find that the film thickness and the volume ratio of CO₂/electrolyte fed to the reactor significantly affect the current density and the faradaic efficiency. Additionally, we find industrially relevant performance when operating the reactor at an elevated pressure beyond 5 bar. We compare our predictions with numerical simulations based on the unit cell approach, showing good agreement for a large window of operating parameters, illustrating when the easy-to-use predictive expressions for the current density and faradaic efficiency can be applied.