More sieve plate towers are used for the lower tower from 15000 to 50000 grades. The diameter tower with circulating tray below 15000 grades has advantages (the liquid flow is longer than convection, but the manufacturing is complex). The convection tower below 30000 grades is used more, the large tower with four overflow streams above 30000 grades has advantages, and the packed tower has low energy consumption.

In the equipment of oxygen production based on the principle of low-temperature distillation, in order to ensure the normal rectification and separation of air in the low-temperature area, the air must be pretreated in the normal temperature area, such as filtration, precooling and purification. The air contains a lot of dust. During the long-term high-speed operation of the air turbine compressor (hereinafter referred to as the air compressor)