Air purification and vapor recovery by pressure swing adsorption: A comparison of silicalite and activated carbon

Air purification and vapor recovery by pressure swing adsorption (PSA) were experimentally investigated using the silicalite-DMMP-air system. The results from several cyclic steady-state PSA runs were compared at constant throughput with those from a previous study on the BPL activated carbon-DMMP-air system. The performance of BPL activated carbon was superior to that of silicalite because it demonstrated complete cleanup of the product effluent when starting from a saturated column, whereas, at similar process conditions, silicalite was able to cleanup only a portion of the product effluent. Nevertheless, both silicalite and BPL activated carbon respectively demonstrated enrichments (Ye!Yf) of 12 and 15 using only moderate vacuum. However, there were significant differences in the shapes of the cyclic steady-state product and exhaust profiles which were attributed to differences in the 1) mass transfer rates, 2) adsorption capacities, or 3) possibly shapes of the adsorption isotherms.