1. PSA oxygen production

The core of adsorption and separation is adsorbent. The commonly used adsorbent is spherical or cylindrical particles, with micropores on the surface and different colors. When the gas flow passes through the adsorbent, the components with large force with the micropores are adsorbed by the micropores, and the components with small force can flow through the micropores. So as to realize the adsorption and separation of components. Under the condition of adsorption equilibrium, low temperature and high pressure will increase the adsorption capacity. On the contrary, high temperature and low pressure will reduce the adsorption capacity. Therefore, the adsorption and separation method of gas usually adopts two cycle processes: temperature swing adsorption or pressure swing adsorption. Among them, pressure swing adsorption (PSA) is the most widely used, mature technology and low comprehensive cost oxygen production method.

The concentration of oxygen obtained from PSA oxygen production is about 90 ~ 95% and the pressure is about 0.4MPa. The unit energy consumption decreases slightly with the increase of production capacity, which is related to the purity of oxygen. PSA method is suitable for oxygen production in small and medium-sized production capacity.

2. VPSA vacuum pressure swing adsorption oxygen production

The adsorption principle of VPSA (vacuum pressure swing adsorption) is similar to PSA, but the adsorption pressure is much lower than PSA. Under the condition of penetrating atmospheric pressure, VPSA oxygen production equipment uses VPSA special molecular screening to selectively adsorb nitrogen, carbon dioxide, water and other impurities in the air, and desorbs the molecular sieve under the condition of vacuum, so as to recycle and produce oxygen with high purity (90 ~ 95%). VPSA has low energy consumption. The larger the equipment, the lower the unit energy consumption.

The concentration of oxygen from VPSA oxygen production is about 90 ~ 93%, and the outlet pressure is slightly higher than that of atmospheric pressure. The larger the production capacity, the lower the increasing proportion of energy consumption. VPSA is suitable for oxygen production with large capacity.

3. Oxygen production by membrane separation

Membrane separation method is to separate oxygen from air by using the permeability selectivity of organic polymeric membrane. When air passes through the oxygen making membrane, oxygen is easier to penetrate out of the membrane than nitrogen, so as to realize the separation of oxygen and nitrogen.

The oxygen enriched membrane needs to be replaced regularly for membrane separation oxygen production, so the cost of oxygen production is high. The maximum oxygen concentration is about 40%, and the pressure is slightly higher than that of atmospheric pressure. (nitrogen concentration of membrane separation is up to about 95%)