| 摘要 |
In the oxygen enrichment of air at a temperature of 20 to 50.degree.C by means of vacuum swing adsorption (VSA) or pressure swing adsorption (PSA) or by means of a combination of VSA and PSA, wherein the air is passed through an adsorber which is filled with packings of zeolite pellets, the improvement which comprises providing at least one packing at each of the air inlet to and air outlet from the adsorber, the packing at the air inlet side of the adsorber comprising Na-Ca zeolite X with an SiO2/Al2O3 ratio of 2.0 to 2.5 and with a CaO/Al2O3 ratio of 0.4 to 0.75, the ratio being dependent upon the air inlet temperature, at an air inlet temperature of 20 to 30.degree.C the CaO/Al2O3 ratio of the Na-Ca zeolites X at the inlet zone being 0.4 to 0.6, at an air inlet temperature of 30 to 40.degree.C the CaO/Al2O3 ratio of the Ca zeolite X at the inlet zone being 0.55 to 0.65 and at an air inlet temperature of 40 to 50.degree.C the CaO/Al2O3 ratio of the Na-Ca zeolite X at the inlet zone being 0.6 to 0.75, the packing at the air outset side of the adsorber comprising Na-Ca zeolite A with a CaO/Al2O3 ratio of 0.5 to 1.0 or Na-Ca zeolite X with CaO/Al2O3 ratio of 0.4 to 1.0, above the CaO/Al2O3 ratio of the Na-Ca zeolite X at the inlet side. As a result the efficiency is improved.
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