Separation of CO2/N2 Mixture by Vacuum Pressure Swing Adsorption

Separation is usually one of the costly stages in chemical and petrochemical industries. Pressure Swing Adsorption (PSA) is an important unit for gas separation and purification. In order to develop the PSA technology, a pilot plant including four beds each with 1 meter length and 3.5 centimeter diameter was designed and built in Tarbiat Modares University. This pilot includes vaccum pump, control systems and analysis systems to study the operational conditions of beds carefully. In order to test this pilot plant, separation of CO2 /N2 mixture using Zeolite 13X type and carbon molecular sieve was studied. In this study an 8 stage cycle including: repressurization with feed, adsorption, equalization to depressurization, blow down, purge in medium pressure, equalization to pressurization, evacuation and preloading was used. The test have been done in pressure range of 2.7 to 4.7 bar, cycle time of 400 to 640 seconds and 3 product flow rate (1, 2, 3 L/min). The effects of pressure, cycle time and product flow rate were studies, using 560 seconds for a cycle time at 3.7 bar, the maximum purity of 97.6% was obtained.