PSA Processes for Recovery of Carbon Dioxide

Abstract

Carbon dioxide is considered the main cause of global warming. For sustainable development, efforts are being undertaken to mitigate the emission of CO2 to the atmosphere. The pressure swing adsorption (PSA) process is a highly efficient gas separation process and also applied for the removal of carbon dioxide from various gas mixtures PSA processes are studied for the recovery of carbon dioxide from various sources including steel mill offgas, petrochemical waste gas, and combustion flue gas. The 1-stage PSA process is applied when the concentration of CO2 is higher than 25% like the steel mill off-gas and petrochemical waste gas. The 1-stage PSA process generally consists of four steps; pressurization with feed gas, adsorption, high pressure rinse with product CO2, and evacuation. Especially, when the feed contains about 25% CO2, performing low pressure purge and recycling the effluent to the feed inlet greatly enhances the process performance. In a typical run, a high purity CO2 of 99% is produced with recovery of 80% from feed gas containing 25% CO2. The 2-stage PSA process is more efficient than 1-stage PSA when the concentration of CO2 is low. At the first stage of the 2-stage PSA, CO2 is concentrated to 40-60% from the feed of less than 15% CO2 and then concentrated to 99%, at the second stage. With the 2-stage PSA process composed of 2-bed for each stage, 99% CO2 is recovered with 80% recovery from the feed containing 11% CO2.