Industrial oxygen generator PSA oxygen production plant

Pressure swing adsorption (PSA) for oxygen production uses air as raw material and carbon molecular sieve as adsorbent. Using the principle of pressure swing adsorption, the carbon molecular sieve filled with micropores selectively adsorbs gas molecules and obtains 90%-93% oxygen.

The pressure swing adsorption equipment mainly consists of two adsorption towers with carbon molecular sieves A and B and control systems equipped. When compressed air (typically 0.8 MPa) passes through the A column from bottom to top, oxygen, carbon dioxide and moisture are adsorbed by the carbon molecular sieve, while nitrogen is passed through and flows out of the top of the column.

When the molecular sieve in the A column is saturated, it is switched to the B column to carry out the above adsorption process and simultaneously regenerate the A column molecular sieve. The regeneration, that is, the gas in the adsorption tower is vent to the atmosphere to rapidly reduce the pressure to atmospheric pressure, and then the oxygen, carbon dioxide and water adsorbed by the molecular sieve are released from the molecular sieve.

Reasonable adsorption tower structure to increase the utilization rate of oxygen molecular sieve
The layout design of the internal structural parts of the adsorption tower is very important to the use of carbon molecular sieve, which is mainly manifested in three aspects:
1. Protect the bed of oxygen molecular sieve
2. Buffer stable high-pressure airflow
3. Uniformly distribute air flow. In order to solve the problem of molecular sieve gaps caused by insufficient filling of carbon molecular sieves, the "tunneling effect" is triggered during the pressure increase and decrease process.

Principle: The pore size distribution characteristics of carbon molecular sieve enable it to realize the kinetic separation of O2 and N2. The pore type distribution is shown in Figure 2 on the right: this pore size distribution allows different gases to diffuse into the pores of the molecular sieve at different rates. , Without repelling any kind of gas in the mixture (air).

The separation effect of carbon molecular sieve on O2 and N2 is based on the small difference in the dynamic diameter of the two gases. The dynamic diameter of O2 molecules is small, so there is a faster diffusion rate in the micropores of carbon molecular sieve. The kinetic diameter is larger, so the diffusion rate is slower. The diffusion of water and CO2 in compressed air is not much different from that of oxygen, while the diffusion of argon is slower. The final enrichment from the adsorption tower is a mixture of N2 and Ar.