Carbon Dioxide Capture from Flue Gas by Vacuum Swing Adsorption

Abstract

The focus of the present study is designing and developing an adsorption process for CO2 capture from wet flue gas at high purity and recovery with minimum energy consumption. This involved measurement of adsorption equilibrium, pilot scale demonstration of CO2 capture and modeling and optimization of a vacuum swing adsorption process. Zeolite 13X and silica gel were the adsorbents used in this study. Single component equilibrium of CO2 and N2 were obtained from gravimetry and breakthrough experiments were used to predict binary equilibrium. The pilot scale demonstration comprised of breakthrough experiments, basic 4-step and 4-step VSA with light product pressurization (LPP). Further, the VSA process was simulated to capture and concentrate CO2 from a wet flue gas. A dual-adsorbent 2-bed, 4-step VSA process consisting of silica gel and 13X was proposed. Detailed optimization studies were carried out to obtain the minimum energy consumption in the proposed VSA process.