CO₂ from carbonate-based capture solutions requires a substantial energy input. Replacing this step with (bi)carbonate electrolysis has been commonly proposed as an efficient alternative that coproduces CO/syngas. Here, we assess the feasibility of directly integrating air contactors with (bi)carbonate electrolyzers by leveraging process, multiphysics, microkinetic, and technoeconomic models. We show that the copresence of CO₃^2– with HCO₃^– in the contactor effluent greatly diminishes the electrolyzer performance and eventually results in a reduced CO₂ capture fraction to ≤1%. Additionally, we estimate suitable effluents for (bi)carbonate electrolysis to require 5–14 times larger contactors than conventionally needed contactors, leading to unfavorable process economics. Notably, we show that the regeneration of the capture solvent inside (bi)carbonate electrolyzers is insufficient for CO₂ recapture. Thus, we suggest process modifications that would allow this route to be operationally feasible. Overall, this work sheds light on the practical operation of integrated direct air capture with (bi)carbonate electrolysis.

中文翻译：

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闭环：直接空气捕获与碳酸氢盐电解集成的未经检验的性能权衡

来自基于碳酸盐的捕获解决方案的CO ₂需要大量的能量输入。人们普遍提出用碳酸氢盐电解代替这一步骤作为联产二氧化碳/合成气的有效替代方法。在这里，我们通过利用过程、多物理场、微动力学和技术经济模型来评估将空气接触器与碳酸氢盐电解槽直接集成的可行性。我们发现，接触器流出物中 CO ₃ ^2–与 HCO ₃ ^–的共存极大地降低了电解槽的性能，并最终导致 CO ₂捕获率降低至 ≤1%。此外，我们估计适合碳酸氢盐电解的流出物需要比传统所需接触器大 5-14 倍的接触器，从而导致不利的工艺经济性。值得注意的是，我们表明碳酸氢盐电解槽内捕获溶剂的再生不足以重新捕获 CO ₂。因此，我们建议对工艺进行修改，以使这条路线在操作上可行。总体而言，这项工作揭示了直接空气捕获与碳酸氢盐电解集成的实际操作。