How to realize oxygen gas purification

Liquid air fractionation is widely used in large-scale production of oxygen in industry.

First, make the air pass through the filter to remove dust and other solid impurities, enter the compressor for compression, and then pass through the molecular sieve purifier to remove water vapor, carbon dioxide and other impurities. Here, molecular sieve can make smaller molecules such as nitrogen and oxygen pass through and play a role in screening molecules. Then cooling and depressurization are carried out. When the temperature drops to about - 170 ℃, the air begins to be partially liquefied and enters the distillation tower, and fractionation is carried out according to the different boiling points of various gases in the air. The boiling point of liquid oxygen is higher than that of liquid nitrogen, which is easier to gasify than liquid nitrogen. More than 99% pure oxygen can be obtained by multi-step fractionation, and nitrogen and raw materials for extracting rare gases can be obtained at the same time.

Oxygen purification

This method is complicated. If oxygen with low purity is needed, air can be separated by molecular sieve adsorption method to obtain oxygen. The adsorption capacity of specific molecular sieve for nitrogen is greater than that of oxygen. When the air passes through the molecular sieve bed, the oxygen content of the gas flowing out is higher, and the gas with oxygen content of 70~80% can be obtained through multiple adsorption. This method is normal temperature operation, short cycle time and easy to realize automation.

In addition, if high-purity oxygen is needed, electrolytic water method can be used for production. This method has high cost and is only suitable for small-scale production.

The oxygen separated from the air is generally stored in blue steel cylinders under pressure for industrial, medical or other purposes.