Parametric Analysis of a Moving Bed Temperature Swing Adsorption (MBTSA) Process for Postcombustion CO₂ Capture

Abstract

We simulate a moving bed temperature swing adsorption (MBTSA) process to capture CO2 in postcombustion context using zeolite 13X as adsorbent. Experimental adsorption isotherms for CO2 and N2 were performed gravimetrically to obtain the equilibrium input data for the model. The need of the flue gas drying was demonstrated by pure water and binary water/CO2 experimental adsorption isotherms, and the energy penalty of the water removal was accounted for within the energetic duty of the unit. The model consists of three sections (adsorption, regeneration, and cooling) each with its own model and integrated by a composite model that simulates the entire unit. Given the large number of variables and parameters in a MBTSA process, which can be arranged in different input data sets, a parametric study of the effect of several variables (feed gas flow rate, regeneration temperature, adsorbent residence time in the adsorption section, feed temperature, solid loading) on the key performance parameters of the process was performed. The results showed that, under the studied conditions, values up to 99% and 91% mol of CO2 recovery and purity could be achieved, respectively. The specific energy consumption, which included an energy recovery in the cooling section, was found to be competitive against reported values for commercial amine absorption separation processes suggesting that the MBTSA process might be a potential separation process candidate for large-scale postcombustion CO2 capture by adsorption.