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What's the difference between VPSA and PSA oxygen generator?


Industrial oxygen production mainly uses VPSA and PSA oxygen production equipment.

VPSA (Vacuum Pressure Swing Adsorption) oxygen production equipment. Using the selectively character by the mixed bed formed by lithium molecular sieve and desiccant to adsorb impurities such as N2, CO2 and H2O in the air, so that oxygen accumulates and collects at the end of the bed, and absorbs the saturated molecular sieve bed under vacuum conditions Desorption is carried out, so that oxygen with higher purity (90-95%) is produced cyclically.


PSA (Pressure Swing Absorption) oxygen production equipment is a new gas separation technology. Taking adsorbent molecular sieve as an example, the principle is to use molecular sieve to "adsorb" different gas molecules. Separate the gas mixture. It uses air as raw material, and uses a high-efficiency, high-selectivity solid adsorbent to selectively adsorb nitrogen and oxygen to separate nitrogen and oxygen from the air. Zeolite molecular sieves selectively adsorb molecules according to the size of the pores inside the crystal, adsorb molecules of a certain size and repel molecules of larger substances. In this way, oxygen-rich components can be obtained in the gas phase. After a period of time, the adsorption of nitrogen by the molecular sieve reaches equilibrium. According to the different characteristics of the adsorption capacity of the zeolite molecular sieve under different pressures, the pressure is reduced to release the adsorption of nitrogen by the zeolite molecular sieve. This process is called regeneration. The pressure swing adsorption method usually uses two towers in parallel to alternately perform pressure adsorption and decompression regeneration to obtain a continuous oxygen flow.


Principle

VPSA oxygen production equipment is mainly composed of blower, vacuum pump, cooler, adsorption system, oxygen buffer tank, and control system.

1. Air blower and vacuum pump, the blower provides raw air for the entire system. According to the design conditions of the VPSA oxygen generator and the user's use conditions, select the exhaust pressure to supply air to the blower that meets the design conditions. The vacuum pump ensures the normal analysis of the entire system, keeps the system in an ideal vacuum state, and enables the entire equipment to continuously absorb nitrogen and produce oxygen.

2. Cooler: The high temperature and high pressure compressed air which is obtained after the blower is pressurized, and then the air temperature is reduced to the required process operation temperature through the water cooler, and then sent to the adsorption tower for adsorption.

3. Adsorption system, the adsorption system consists of two adsorption towers and pipeline valves equipped with zeolite molecular sieve adsorbents. Compressed air with low temperature and high pressure enters from the bottom of Tower A. When it flows through the adsorbent layer, nitrogen, carbon dioxide, water vapor in the air are adsorbed. The oxygen is collected through the adsorption bed to the top of the adsorption tower as product gas output. At the same time, Tower B is in regeneration mode. When the adsorption tower performing adsorption is about to reach adsorption saturation, under the adjustment of the control system, the low-temperature and high-pressure air is transferred to Tower B to start adsorption and oxygen production. Towers A and B alternately achieve the purpose of continuous oxygen production in this way.

4. Oxygen buffer tank stores product gas (oxygen) and stabilize the entire equipment.

5. Control system, the engineer inputs the pre-written valve control program into the PLC controller, and adjusts the opening and closing of each pneumatic valve through the solenoid valve to realize the adsorption and regeneration of the adsorption system within the specified time.

PSA oxygen production equipment is mainly composed of air compressor, refrigeration dryer, deoiler, adsorption system, oxygen buffer tank, and control system.

1. Air compressor, the air compressor provides raw air for the entire system. According to the air output of the pressure swing adsorption oxygen production equipment, select an air compressor that meets the design conditions for air supply.

2. Cold dryer, after the air compressor pressurizes the raw air, the high temperature and high pressure compressed air enters the cold dryer for cooling, drying, and impurity removal to obtain low temperature and high pressure compressed air.

3. Degreasing device, the degreasing device removes the oil mist in the low temperature and high pressure compressed air to prevent the oil mist in the air from affecting the life of the zeolite molecular sieve.

4. Adsorption system, the adsorption system consists of two adsorption towers and pipeline valves equipped with zeolite molecular sieve adsorbents. Compressed air with low temperature and high pressure enters from the bottom of Tower A. When it flows through the adsorbent layer, nitrogen, carbon dioxide, water vapor in the air are adsorbed. The oxygen is collected through the adsorption bed to the top of the adsorption tower as product gas output. At the same time, Tower B is in regeneration mode. When the adsorption tower performing adsorption is about to reach adsorption saturation, under the adjustment of the control system, the low-temperature and high-pressure air is transferred to Tower B to start adsorption and oxygen production. Towers A and B alternately achieve the purpose of continuous oxygen production in this way.

5. Oxygen buffer tank stores product gas (oxygen) and stabilize the entire set of equipment.

6. Control system, the engineer inputs the pre-written valve control program into the PLC controller, and adjusts the opening and closing of each pneumatic valve through the solenoid valve to realize the adsorption and regeneration of the adsorption system within the specified time.


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