New performance indicators for adsorbent evaluation derived from a reduced order model of an idealized PSA process for CO2 capture

As adsorption is being considered as a candidate technology for CO2 capture, a variety of new adsorbents are being developed, such as those based on novel materials like metal-organic frameworks (MOFs) and zeolitic imidazolate frameworks (ZIFs). New adsorbents are typically evaluated based on measures like working capacity and selectivity, which can be easily calculated using isotherm data. However, these indicators do not directly consider the adsorbents' performance in their end application, which typically is the pressure swing adsorption (PSA) process. Motivated by this, this work presents alternative indicators of adsorbent material's performance evaluated specifically in the context of the PSA process. In order to keep their use simple and general, the proposed indicators are formulated assuming an idealized PSA process. Analytical expressions are derived wherever possible. In a case study involving several real adsorbents, the indicator values are compared to the results from the dynamic simulation of the PSA process and to the conventional working capacity and selectivity values.