1. Membrane separation

Due to the permeability selectivity of some organic polymer membranes, when air passes through the membrane (0.1um) or hollow fiber membrane, the speed of oxygen passing through the membrane is about 4-6 times that of nitrogen, thus realizing the separation of oxygen and nitrogen. This method has the advantages of simple installation, convenient operation, fast start-up and less investment. But its oxygen concentration is relatively low, generally between 28% - 35%, so it is generally used in places with low oxygen purity.

2. Electrolysis

The principle adopted is to ionize water with direct current in dilute sulfuric acid, sodium hydroxide or sodium sulfate aqueous solution. Every 1m3 of oxygen is produced and 2m3 of hydrogen is obtained at the same time. However, because the power consumption of producing 1m3 oxygen is between 12-15 degrees, this method can not be mass produced.

3. Pressure swing adsorption

Molecular sieve oxygen generator is an advanced gas separation technology. Physical method (PSA method) directly extracted oxygen from the air, fresh and natural. The medical oxygen generator is filled with molecular sieve, and the surface area of each gram of molecular sieve can reach 800-1000m2 / g. under the pressure condition, the physical adsorption technology and desorption technology of molecular sieve are used to adsorb nitrogen in the air. The unabsorbed oxygen will be collected and purified to obtain high purity oxygen. Molecular sieve oxygen generator is a mature oxygen generator with international and national standards, which can realize periodic oxygen production. This is a dynamic process, there is no danger of high pressure and explosion.

4. Chemical method

Chemical oxygen production is a method of producing oxygen by decomposing oxygen rich compounds by chemical reaction. The cost of this method is low, but the consumption of raw materials for long-term use is relatively large, resulting in high cost. At the same time, the production capacity of this method is too small to produce a large amount of oxygen. At present, it is only used in the production of small household portable oxygen generator.

5. Low temperature method

First, the air is cooled by compression and expansion until the air is liquefied, and then oxygen and nitrogen are used at low temperatures (boiling points) of oxygen and nitrogen. In the distillation tower of a certain equipment, oxygen first turns into liquid and flows out for air separation. The scale of this method is relatively large, which is more than several thousand cubic meters per hour. The equipment is characterized by large investment, long gas production time, complex equipment, large floor area and high requirements for operators. It is generally used as the application and supply of large oxygen equipment.