Deployment of post-combustion carbon dioxide (CO₂) capture technologies is needed to reduce emissions from power and industrial sources. Comparisons between existing thermochemical CO₂ capture methods and emerging electrochemical concepts can help contextualize the promise of these new approaches. Here, we investigate the required absorber sizes for three capture systems: amine scrubbing using monoethanolamine (MEA), direct electrochemical (redox-active sorbent), and indirect electrochemical (pH swing). For the electrochemical systems, we study how column size varies as a function of molecular properties and operating conditions, finding that parameters most closely related to CO₂ uptake rates (i.e., rate constants and pK_a) have the greatest impact. Through a Monte Carlo analysis, we find that the direct process can be designed to have column sizes similar to the thermochemical process; however, the CO₂ uptake rate in the indirect process is too slow to enable smaller columns. Broadly, this work connects system input parameters to absorber performance for electrochemical CO₂ capture and provides a foundation for techno-economic and engineering analyses.

中文翻译：

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电化学和热化学碳捕获系统中 CO2 吸收塔的建模和比较分析


需要部署燃烧后二氧化碳 （CO₂） 捕获技术，以减少电力和工业源的排放。将现有的热化学 CO₂ 捕获方法与新兴的电化学概念进行比较，有助于了解这些新方法的前景。在这里，我们研究了三种捕获系统所需的吸收器尺寸：使用单乙醇胺 （MEA） 的胺洗涤、直接电化学（氧化还原活性吸附剂）和间接电化学（pH 波动）。对于电化学系统，我们研究了色谱柱尺寸如何随分子特性和操作条件而变化，发现与 CO₂ 吸收速率最密切相关的参数（即速率常数和 pK_a）的影响最大。通过蒙特卡洛分析，我们发现直接工艺可以设计为具有与热化学工艺相似的色谱柱尺寸;然而，间接工艺中的 CO₂ 吸收速率太慢，无法实现更小的色谱柱。从广义上讲，这项工作将系统输入参数与电化学 CO₂ 捕获的吸收器性能联系起来，并为技术经济和工程分析提供了基础。