Pressure swing adsorption repressurization

Processes involving total-pressure reduction to remove the adsorbed species, called pressure-swing adsorption (PSA) or heatless adsorption, are mechanically complex, since they must include separate adsorption, depressurization, desorption, and repressurization steps. To accommodate a steady flow of feed and products, several beds - usually three or more in parallel -are used. A typical four-bed process flowsheet is shown in... 

Steps. A pressure-swing cycle has at least three steps adsorption, blowdown, and repressurization. Although not always necessary, a purge step is normally used. In finely tuned processes, cocurrent depressurization and pressure-equalization steps are frequendy added. 

Repressurization of the adsorber to feed pressure completes the steps of a pressure-swing cycle. Pressurization can be done with product and/or i. When piquet is used, it should be applied countercurrent to adsorption to continue put png of the effluent end. Pressurization with feed should be carried out cocurrent to adsorption to prevent contamination of the effluent end. 

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