The air contains a small amount of water vapor, carbon dioxide, acetylene, hydrocarbon and a little dust and other impurities. If these impurities are allowed to enterAir separation equipment, It will be very dangerous, solid impurities will wear the device, especially threaten the safe operation of high-speed rotating equipment, bring into the heat exchanger will also pollute the heat transfer surface, reduce the heat transfer effect; water vapor and CO2It will freeze and precipitate in succession under the condition of low temperature, so as to block the gas Channel and the sieve hole of the tower plate; the overaccumulation of acetylene and hydrocarbon tables in the distillation column is easy to cause explosion. Therefore, in order to improve the safety, reliability and economy of the unit operation, the air must be purified.