In low-temperature ${\mathrm{C}\mathrm{O}}_2$ electrolysis, a fundamental trade-off exists between maximizing electrolyzer performance and minimizing downstream ${\mathrm{C}\mathrm{O}}_2$ recovery. By coupling a down-the-gas-channel electrolyzer model with a techno-economic analysis, we find that the optimal single-pass ${\mathrm{C}\mathrm{O}}_2$ conversion for ethylene production is typically low—on the order of 5%–10%—although larger optima are found if the ${\mathrm{H}}_2$ faradic efficiency is very low. Similarly, strategies for eliminating carbonate crossover require more energy than downstream gas separation if they increase the cell potential by ∼0.2 V; however, when CAPEX are accounted for, this “break-even” voltage increases to ∼ 0.4 to 0.8 V for electricity prices varying from 6c/kWh to 1.5c/kWh. These findings are a consequence of the low energy requirements of industrial gas separation relative to electrochemical ${\mathrm{C}\mathrm{O}}_2$ reduction. Under most circumstances, maintaining near-optimal electrolyzer performance is more important than reducing or eliminating downstream gas separations.

在低温${\mathrm{C}\mathrm{欧}}_{\mathrm{2个}}$电解，在最大化电解槽性能和最小化下游之间存在一个基本的权衡${\mathrm{C}\mathrm{欧}}_{\mathrm{2个}}$恢复。通过将气体通道下的电解槽模型与技术经济分析相结合，我们发现最佳的单程${\mathrm{C}\mathrm{欧}}_{\mathrm{2个}}$乙烯生产的转化率通常很低——大约 5%–10%——尽管如果${\mathrm{H}}_{\mathrm{2个}}$法拉第效率很低。类似地，如果消除碳酸盐交叉的策略将电池电位提高 ~0.2 V，则需要比下游气体分离更多的能量；然而，当考虑资本支出时，对于从 6c/kWh 到 1.5c/kWh 不等的电价，这个“盈亏平衡”电压增加到大约 0.4 到 0.8 V。这些发现是工业气体分离相对于电化学的低能量需求的结果${\mathrm{C}\mathrm{欧}}_{\mathrm{2个}}$减少。在大多数情况下，保持接近最佳的电解槽性能比减少或消除下游气体分离更为重要。