Process-level evaluation methodologies and parameter library for $CO_2$ capture adsorbents

Abstract

This study contributes to the evaluation of $CO_2$ capture adsorbents by proposing models, methods, strategies, and tools helping the evaluation for both molecule-level and process-level analysis. For the molecule-level analysis, a new isotherm model is proposed to address the S-shaped isotherm data, which have received increasing attention because of its remarkable potential in $CO_2$ capture processes. By generalizing the model and deriving its spreading pressure, this model is improved in aspects of its applicability and computational efficiency. For the process-level evaluation, an ideal pressure swing adsorption (PSA) process is assumed, and the influence of isotherm parameters on the process is derived mathematically, which leads to a shortcut evaluation method. From the derived method, product $CO_2$ purity and energy efficiency are analytically formulated. This simple and fast evaluation method enables the comparative evaluation of many sorbents. For its practical use, several strategies are established by categorizing the situations where the adsorbents are employed in the PSA process. These strategies achieve significant improvement in the computational efficiency and stability of this evaluation work. With the molecular simulation results including isotherm data of thousands of adsorbents, an isotherm parameter library is also established. With this library, the method and strategies of this study are combined, and a software is developed with graphical user interface (GUI), which is named general adsorption library and evaluation (GALE). With this software, a variety of adsorbent evaluation with different situations can be carried out, and its results are provided with the sorbent rankings. This software is available on its website.