Investigations of turbulence influence on pressure swing adsorption process for CO2 capture by computational mass transfer

Abstract

Capture, utilization, and storage of CO2 (CCUS) is an effective way to achieve a low carbon and sustainable future, and PSA is one of the CO2 separation technologies that has been widely studied due to its advantages of simple equipment and low energy consumption. The uncertain flow state of the fluid can indeed have an impact on accurate modeling during the research process of capturing CO2 with PSA. In this study, we compare the two-equation turbulent (TET) model based on the computational mass transfer method (Yu and Yuan, 2017 [1]) with the laminar model commonly assumed in previous studies, to investigate the dynamic PSA process involving multi-steps of carbon dioxide separation in a single-column, with the purpose of exploring the differences caused by selecting different flow state models during the modeling process. The study utilizes the two models to simulate a single column PSA process, which consists of adsorption, vacuuming, purging, and pressurization to capture CO2. The simulation results are compared with experimental data, and compared to the laminar model, the TET model is found to be more in line with the actual process. The effect of turbulent diffusion on the concentration and velocity distributions is also investigated by comparing the two models, and the radial distribution becomes more uniform as the turbulent diffusion is taken into account in the TET model. The intensity of turbulent diffusion is analyzed for each step, and the pressurization stage shows intense turbulent characteristics that will impact the whole process.