Pressure conversion adsorption vacuum desorption (VPSA for short) oxygen generation equipment, that is, using VPSA special molecular sieve to selectively absorb nitrogen, carbon dioxide, water and other impurities in the air under the condition of penetrating atmospheric pressure, the molecular sieve is desorbed under the condition of vacuum, thus the oxygen with higher purity (90-94%) is produced through circulation ). The energy consumption of VPSA is low. The larger the device is, the lower the energy consumption is.
◇Process description
VPSA oxygen generation system mainly consists of blower, vacuum pump, switch valve, adsorber and oxygen balance tank. After removing the dust particles through the suction inlet filter, the raw Air is pressurized to 0.3-0.5barg by Roots blower and enters into one of the adsorbers. The adsorber is filled with absorbents, in which moisture, carbon dioxide and a small amount of other gas components are adsorbed by activated alumina filled at the bottom at the entrance of the adsorber, then nitrogen is adsorbed by the zeolized molecular sieve filled on the upper part of activated alumina. However, oxygen (including argon) is a non-adsorptive component, which is discharged from the top exit of the adsorber as product gas to the oxygen balance tank.
When the adsorber is adsorbed to a certain extent, the adsorber in it will reach the saturation state. At this time, the vacuum pump is used to vacuum it through the switch valve (opposite to the adsorption direction), and the vacuum degree is 0.65-0.75 barg. The adsorbed water, carbon dioxide, nitrogen and a small amount of other gas components are extracted and arranged to the atmosphere side by side, and the adsorbents are recycled.
Each adsorber of VPSA performs the following steps alternately:
--- Adsorption --- desorption --- stamping
The above three basic process steps are automatically controlled by PLC and switching valve system.
◆Craft features
1. The energy consumption is relatively low. The higher the oxygen production is, the lower the energy consumption is.
2. The maintenance cost is low, and the movable equipments are Roots blower and roots vacuum pump. Because their working principles are both positive volume type and no oil, they are easy to maintain.
3. The whole equipment has a high degree of automation. The dynamic equipment and the oxygen generator are controlled synchronously. Just press the start button, and the whole equipment can run normally.
4. Suitable for medium and large output.
Variable Pressure adsorption oxygen generation has been widely used in non-ferrous metal smelting (copper smelting, lead smelting, gold smelting, etc.) due to its characteristics of fast start-up, low energy consumption, simple operation, large load operation adjustment range and simple maintenance, etc), ferrous metal smelting (blast furnace oxygen-enriched coal injection iron making, electric furnace steelmaking, etc.), chemical gas generation, medical field and sewage treatment (oxygen-enriched gas explosion), etc.
