NEW PRESSURE SWING ADSORPTION PROCESS WITH COLUMNS UNCOUPLED
A pilot set-up was built to test a novel four-bed pressure swing adsorption (PSA) process with a hydrogen-separation operation.The new PSA process features intermediate surge tanks, through which depressurization and re-pressurization of columns are accomplished. As consequence, the coupling between columns via pressure-equalization is disconnected, and the possibility of operating the process at lower pressure is provided. A new cycle sequence was suggested for the new PSA process. Operations of separating hydrogen from a mixture of H 2/N 2/CH 4 of molar ratio 60/10/30, which simulated the dry gas of refineries, were performed on such process at pressures lower than 1.0 MPa. Process performance was studied with columns packed consecutively with adsorbents composed of ordinary activated carbon (OAC) with ZMS-5A, and that of superactivated carbon(SAC) with ZMS-5A for the pressure range 0.4—1.0 MPa. It was proven that a relatively high recovery and as high as 99.99% of purity of the product could be realized at low pressures with the new PSA technology.