Modification Of X-type Zeolite And Oxygen-enriched Capacity

X zeolite molecular sieves are widely used in pressure swing adsorption?PSA?because of their good nitrogen and oxygen adsorption and separation capabilities.In this paper,13X molecular sieve was used as raw material,the molecular sieve was treated with alkali and the molecular sieves containing different cations were prepared.The adsorption separation abilities and oxygen enrichment abilities of X zeolite under different modification conditions were investigated.The main conclusions are as follows:?1?The molecular sieves treated by Na₂CO₃ solution showed that the ratio of silica to aluminum decreased,but the basic structure unchanged,the crystallinity became higher,the arrangement of the zeolites became regular,but the thermal stability of the molecular sieves decreased.The adsorption results showed that the adsorption of N₂ and O₂ on the samples increased.Molecular sieve treated by Na₂CO₃ solution for 12 hours had the maximum adsorption capacity,the adsorption capacity of N₂ was 8.98 cm³?g^-1 and the adsorption capacity of O₂ was 2.65 cm³?g^-1 at 298 K and 1 bar,and the adsorption selectivity was 3.38.Oxygen concentration increased from 19.56%at the inlet to 24.71%at the outlet.?2?The results show that the basic structure of Co²⁺-containing LiCoX molecular sieves remained unchanged but some structural defects appeared and the crystallinity decreased,but the thermal stability increases.The N₂ adsorption capacity of LiCoX1 is22.44 cm³?g^-1and the adsorption capacity of O₂ is 3.75 cm³?g^-1 at 298 K and 1 bar,the adsorption selectivity was 5.98.Oxygen concentration increased from 19.56%at the inlet to 23.46%at the outlet.?3?The results show that the basic structure of Mg²⁺-containing LiMgX molecular sieves remained unchanged and the thermal stability increased,but its crystallinity decreased,the specific surface area decreased and the zeolite surface became rough.The adsorption results showed that the adsorption capacity of the modified molecular sieve increased,and the N₂ adsorption capacity was 26.34 cm³?g^-1and the adsorption capacity to O₂ was 3.84 cm³?g^-1 at 298 K and 1 bar,and the adsorption selectivity was 6.87.Oxygen concentration increased from 19.56%at the inlet to 24.71%at the outlet.?4?Orthogonal experiments and significance analysis showed that the cationic species in the molecular sieve are the most important factors influencing the enrichment of O₂,followed by the silica-alumina ratio and the ion exchange degree at 298 K and 1 bar.