The electrochemical reduction of carbon dioxide (CO₂RR) to chemical feedstocks, such as ethylene (C₂H₄), is an attractive means to mitigate emissions and store intermittent renewable electricity. Much research has focused on improving CO₂ electrolysis cell efficiency; less attention has been paid to the downstream purification of outlet product streams. In this work, we model the use of mature downstream separation technologies as part of the overall production of polymer-grade C₂H₄ from CO₂. We find that CO₂ removal is the most energy-intensive downstream separation step. We identify opportunities to reduce separation energies to ∼22 GJ/tonne C₂H₄ through necessary improvements in C₂H₄ selectivity (>57%), cathodic CO₂ conversion (>80%), and CO₂ crossover (0 mol CO₂/mol e^–). This work highlights the influence of cell performance parameters on downstream separation costs and motivates the development of new, efficient separation processes better suited to the distinctive outlet streams of CO₂ electrolyzers.

中文翻译：

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CO2 电解槽下游：评估产品分离的能量强度

将二氧化碳 (CO ₂ RR)电化学还原为化学原料，例如乙烯 (C ₂ H ₄ )，是减少排放和存储间歇性可再生电力的有吸引力的手段。许多研究都集中在提高 CO ₂电解槽效率上。对出口产品流的下游净化关注较少。在这项工作中，我们模拟了成熟的下游分离技术的使用，作为从 CO ₂生产聚合物级 C ₂ H ₄的整体生产的一部分。我们发现 CO ₂去除是最耗能的下游分离步骤。我们确定机会减少分离能以约22 GJ /吨C ₂ ħ ₄通过用C必要的改进₂ ħ ₄选择性（> 57％），阴极CO ₂转化率（> 80％）和CO ₂交叉（0摩尔CO ₂ /摩尔^– )。这项工作突出了电池性能参数对下游分离成本的影响，并推动了更适合 CO ₂电解槽独特出口流的新型高效分离工艺的开发。