Screening tools for adsorption based post-combustion CO2 capture

Abstract

Solid-sorbent based CO2 capture holds the promise for reducing energy consumption for post-combustion CO2. The efficacy of a particular sorbent is judged based on simple screening metrics such as selectivity, working capacity or combinations of these. Recently, our group used process optimization to demonstrate that these metrics are poor indicators of sorbent performance at a process scale as they do not take into account the complexities of the process. Hence, the natural question to ask is ?How best to screen solid sorbents by also taking into account process design??. In this presentation, we discuss two approaches to answer this question. The first one is based on rigorous optimization based on detailed models that takes into account heat and mass transfer effects, cycle configuration, process limitations, etc. This approach provides the trade off between energy consumption and productivity. While being rigorous they are computation intensive and not amenable for screening hundreds of materials. The second approach is the development of equilibrium based models that take into account the key aspects of process operation but avoid the complexities of heat and mass transfer. These models are simple and can be solved with minimal computation effort. We show that they provide correct ranking of the materials. These studies provide some counter-intuitive results which can be valuable for designing new solid-sorbents.