VPSA Vacuum Oxygen generator
Working principle of VPSA pressure swing adsorption oxygen generator
1. The main components in the air are nitrogen and oxygen. Nitrogen and oxygen in the air have different adsorption performance on zeolite (ZMS) at ambient temperature (oxygen can be absorbed through nitrogen). Nitrogen on zeolite molecular sieve adsorption ability is better than oxygen (nitrogen ion and molecular sieve surface force strong), when the air pressure in a state with a zeolite molecular sieve adsorbent adsorption bed, nitrogen by molecular sieve adsorption, less oxygen by adsorption, concentration and flow in gas phase adsorption bed, the oxygen and nitrogen separation for oxygen. When the molecular sieve adsorbs nitrogen to saturation, the air is stopped and the pressure of the adsorption bed is reduced. The nitrogen absorbed by the molecular sieve is analyzed and the molecular sieve is regenerated and can be reused. The oxygen can be produced continuously by switching between two or more adsorption beds.
The boiling point of oxygen and nitrogen is close, and the two are difficult to separate. Therefore, the pressure swing adsorption oxygen-making device can only obtain 90-95% oxygen (the polar negative concentration of oxygen is 95.6%, and the rest is argon). Compared with the cryogenic air separation unit, the latter can produce more than 99.5% oxygen concentration.
1. The adsorption bed of the pressure swing adsorption air separation oxygen plant must contain two operation steps; Adsorption and resolution. In order to obtain product gas continuously, more than two adsorption beds are usually installed in the oxygen-making equipment, and some necessary auxiliary steps are also set out from the perspective of energy consumption and stability. Each adsorption bed generally has to go through such steps as adsorption, decompression, vacuuming or decompression regeneration, flushing replacement and even pressure boost, and repeated operations periodically. At the same time, each adsorption bed is in different operation steps. Under the control of PLC, the operation of several adsorption beds can be coordinated and staggered in the practical steps, so that the pressure swing adsorption device can run smoothly and obtain product gas continuously. For the actual separation process, other trace components in the air must also be considered. The adsorption capacity of carbon dioxide and water on the usual adsorbent is generally much greater than that of nitrogen and oxygen, which can be removed by filling the adsorption bed with appropriate adsorbent (or by the oxygen-making adsorbent itself).
The number of adsorption towers required for oxygen production devices depends on the scale of oxygen production, adsorbent performance and process design. The operation stability of multi-tower operation is relatively better, but the equipment investment is relatively high. The current trend is to use highly efficient oxygen sorbent to minimize the number of adsorption towers and to use short operating periods to improve the efficiency of the unit and to save as much investment as possible.
1. Simple equipment process
2. The scale of oxygen production is below 10000m3/h, and the power consumption is lower and the investment is smaller;
3. The amount of civil engineering is small, and the installation period of the device is shorter than that of the cryogenic device;
4. Low equipment operation and maintenance costs;
5. The device has a high degree of automation in operation, convenient and quick to open and stop, and a small number of operators;
6. The device has strong operation stability and high safety;
7. Simple operation, and the main parts are all from internationally renowned manufacturers;
8. Imported oxygen molecular sieves with superior performance and long service life;
9. Strong operational flexibility (superior load line and fast conversion speed).
1. Product size: 100-10000nm3 /h
2. Oxygen purity: 90-94% or greater, which can be adjusted within 30-95% range according to user requirements.
3. Power consumption of oxygen production: when the oxygen purity is 90%, the power consumption converted into pure oxygen is 0.32-0.37kwh/Nm3
4. Oxygen pressure: no more than 20kpa (can be pressurized)
5. Power: greater than or equal to 95%