Published June 1991
This review considers the economics and technology for the production of nitrogen from air by vacuum pressure swing adsorption (VPSA) . The economics are compared with those of producing nitrogen in a conventional pressure swing adsorption system.
Our evaluation shows that the VPSA process has lower utilities costs but higher capital costs than the conventional PSA process. The higher capital costs reflect our assumption that the PSA unit can be built as a module but the VPSA unit cannot, because of the large diameter adsorption beds. The higher production costs for VPSA are due entirely to the higher capital costs.
Capital investment may not be the best basis for comparison of the processes, since nitrogen and other industrial gases are generally sold "over the fence" on a cost of gas basis, with the supplier owning the gas plant.
