(338u) High Temperature CO2 Capture by PSA Using K-Promoted HTlc: Performance Differences Due to Different CO2 Uptake and Release Models in the Literature

Authors: 
Du, H., University of South Carolina
Ebner, A. D., University of South Carolina
Ritter, J. A., University of South Carolina


The reversible adsorption of CO2 at high temperature by K-promoted HTlc has been studied for a decade or so. During this time four different models have been developed that describe the uptake and release of CO2 by this adsorbent. These models vary from being a simple Langmuir type equilibrium model, to a combined chemisorption and physisorption equilibrium mechanism, to a combined chemisorption and reversible equilibrium reaction mechanism, to a non-equilibrium kinetic mechanism. The first three models all utilize LDF mass transfer kinetics, where as the fourth model uses a combination of LDF and non-equilibrium reaction kinetic expressions. All four models describe experimental CO2 loading data quite well on K-promoted HTlc. However, the equilibrium and kinetic properties of CO2 on K-promoted HTlc are seemingly different, as observed from both the experimental data and the models representing that data.

For this reason, all four models were programmed into a PSA process simulator and simulations were carried out using them under identical PSA cycle and process conditions, except for the uptake and release mechanisms. The results were quite surprising, in some cases being similar and in other cases being drastically different, depending on the temperature. This presentation will provide an overview of these results, which are very important to the pre-combustion capture of CO2 or to sorption enhanced reaction processes.