How oxygen gas purification can be achieved

Liquid air fractionation is widely used for large-scale industrial production of oxygen. First, the air is removed through a filter to remove solid impurities such as dust, enters a compressor to compress, and then passes through a molecular sieve purifier to remove impurities suchas water vapor and carbon dioxide. Here, the molecular sieve can allow smaller molecules such as nitrogen and oxygen to pass through, which plays the role of screening molecules. Then cooling and reducing the pressure is carried out, and when the temperature drops to around -170 ° C, the air begins to partially liquefy into the distillation tower, which is divided according to the different boiling points of the various gases in the air. The boiling point of liquid oxygen is higher than that of liquid nitrogen, and both are more easily gasified than liquid nitrogen. Through multi-step distillation, more than 99% of pure oxygen can be obtained, as well as nitrogen and raw materials for the extraction of rare gases.

Oxygen purification

The process of this method is complex. If the purity of oxygen is needed, the air can be separated by molecular siphonation to produce oxygen. The adsorption ability of specific molecular sieves to nitrogen is greater than that of oxygen. When the air passes through the molecular sieve, the outgoing gas contains a higher amount of oxygen, and after several adsorptions, 70 to 80% of the oxygen-containing gas can be obtained. This way is operated at room temperature, short period of batching cycle, easy to automate. In addition, if high purity oxygen is required, it can be produced by electrolytic water, which is costly and is only suitable for small-scale production. Oxygen separated from air is usually stored under pressure in sky blue bottles for industrial, medical or other use.