Development of a General Evaluation Metric for Rapid Screening of Adsorbent Materials for Postcombustion CO2 Capture

Molecular simulations are combined with macroscopic pressure swing adsorption (PSA) modeling and process optimization to screen ∼2900 metal–organic frameworks (MOFs) for their suitability in separating CO2 from N2 under conditions of interest in postcombustion CO2 capture. The hierarchical screening process eliminates MOFs based on metal price, new heuristics based on the internal energy of adsorption, full PSA modeling and optimization, and other factors. Based on PSA modeling of 190 materials, a general evaluation metric (GEM) is developed that can approximately rank the performance of adsorbent materials as defined by the lowest cost for postcombustion CO2 capture. The metric requires only isotherm data and the N2 internal energy of adsorption. The N2 working capacity is the most important component of the metric, followed by the CO2 working capacity, the CO2/N2 selectivity at desorption conditions, and the N2 internal energy of adsorption. Additional analysis shows that the correlation between the cost of CO2 capture and the GEM is better than that of other existing evaluation metrics reported in the literature. For the most promising MOFs, the cost to capture a tonne of CO2 is estimated to be $30–$40 plus the cost of compressing the CO2 product.本研究将分子模拟与宏观变压吸附（PSA）建模及过程优化相结合，针对燃烧后二氧化碳捕集场景下的目标工况，从约2900种金属有机框架（MOFs）中筛选适配于二氧化碳/氮气（CO₂/N₂）分离的材料。该分层筛选流程依次基于金属价格、基于吸附内能的全新启发式规则、完整的PSA建模与优化结果及其他多项指标淘汰不适配的MOFs。基于对190种材料的PSA建模结果，本研究构建了通用评估指标（GEM），可基于燃烧后二氧化碳捕集的最低成本标准，对吸附剂材料的性能进行近似排序。该指标仅需吸附等温线数据与氮气（N₂）吸附内能即可完成计算。其中，氮气工作容量为该指标中权重最高的组成部分，其次为二氧化碳工作容量、脱附工况下的二氧化碳/氮气选择性，以及氮气吸附内能。额外分析表明，本研究所提GEM与二氧化碳捕集成本的相关性优于现有文献中报道的其他评估指标。针对最具应用前景的MOFs，每吨二氧化碳的捕集成本约为30~40美元，该数值未包含二氧化碳产物的压缩成本。