In practical industrial applications, adsorption separation is generally divided into two categories: pressure swing adsorption and temperature swing adsorption. From the adsorption isotherm of the adsorbent, it can be seen that the adsorption capacity of the adsorbent for impurities is large under high pressure and small at low pressure. At the same time, it can be seen from the adsorption isobaric curve that the adsorption capacity of adsorbent is large at low temperature and small at high temperature under the same pressure. The former is called pressure swing adsorption (PSA), and the latter is called temperature swing adsorption (TSA).

In practical industrial application, TSA, PSA or TSA + PSA processes are generally selected according to different gas source composition, pressure and product requirements.

Temperature swing adsorption process needs heating, so it has a long cycle and a large investment, but regeneration is complete. It is usually used for the purification of trace impurities or impurities that are difficult to remove. Pressure swing adsorption process is widely used in the separation and purification of large gas volume and multi-component materials due to its short cycle period, high utilization rate of adsorbent and relatively small amount of adsorbent without additional heat transfer equipment.

In general, in industrial pressure swing method, adsorbent is usually used to adsorb the easily adsorbed components in the mixed gas under normal temperature and high pressure, and the components that are not easy to adsorb flow out from one end of the bed, and then reduce the pressure of the adsorbent bed to make the adsorbed components desorbed and discharged from the other end of the bed, so as to realize the separation and purification of the gas and regenerate the adsorbent at the same time.

However, in the conventional PSA process, when the pressure of the adsorption bed is reduced to atmospheric pressure, the adsorbed impurities can not be completely desorbed, so the adsorbed impurities can be fully regenerated. When the product gas is used for bed washing, it is difficult to absorb the washed impurities. The advantage is that it can be completed under atmospheric pressure, but the disadvantage is the loss of some product gas; The other method is to regenerate the impurities which are forced to be removed under negative pressure by vacuum extraction technology, which is usually called vacuum pressure swing adsorption (VPSA or VPSA or VPSA). VPSA process has the advantages of good regeneration effect, high output and high output, but its disadvantage is the need to increase vacuum pump. In the actual application process, the adoption of the above process mainly depends on the composition of the plant, flow, product requirements, as well as the capital and location of the factory.