Application of metal-organic frameworks in VPSA technology for CO2 capture

One of the technologies that may find application in the reduction of CO2 emissions from both energy and other industrial plants is the adsorption method. Among all adsorption techniques, the Vacuum Pressure Swing Adsorption (VPSA), seems to be the most effective for the separation of CO2 from flue gases, because flue gas is at low pressure. The development of the adsorption method in recent years has been favoured by the intensive development of efficient adsorbents, including metal-organic frameworks (MOFs). Owing to their unique sorption properties and high selectivity, these compounds provide a chance for a considerable reduction of the adsorbent volume, should CO2 be needed to be removed from a huge volume of flue gas. In order to evaluate the possibility of using MOFs, besides zeolites and activated carbon, for CO2 adsorption in large-scale VPSA units, investigations of these compounds in bench-scale and pilot VPSA adsorption units are necessary. In this paper, its authors have carried out investigations into the use of MIL-53(Al) in a bench-scale VPSA installation.. The tests of CO2 separation from a simulated combustion gas mixture on a MIL-53(Al) and on activated carbon and zeolite 13X, respectively, have been carried out in a two-column VPSA installation, which enables adsorbent regeneration in a vacuum. The study also analyzes the effects of adsorption/regeneration time and desorption pressure on CO2 purity and CO2 recovery. The presented results provide new insights into the behaviour of MOFs in the VPSA installation.