The air contains small amounts of water vapour, carbon dioxide, acetylene and hydrocarbons and a little dust and other impurities. If these impurities are allowed to enter the air separation unit, it will be very dangerous: solid impurities will wear the device, threatening the safe operation of high-speed rotating equipment, impurities into the heat exchanger will also contaminate the heat transfer surface, reducing the heat transfer effect; if water vapour and CO2, etc. in low temperature conditions will freeze precipitation, leading to blockage of gas channels and tower plate sieve; acetylene and hydrocarbons in the distillation tower to accumulate too much, easy to trigger an explosion. The accumulation of acetylene and hydrocarbons in the distillation column can lead to explosions. Therefore, in order to improve the safety, reliability and economy of the operation of small air separation unit and large air separation plant, the air must be purified.
Air impurities are solid and gas impurities two, solid impurities including dust, mechanical particles, etc.. Solid impurities are removed in the self-cleaning air filter before the air compressor. Gaseous impurities include: H2O, CO2 and hydrocarbon compounds such as CmHn. The unit uses a front adsorber to purify these gas impurities. The molecular sieve adsorber uses a double-layer horizontal adsorber consisting of aluminium glue and molecular sieve, with the aluminium glue adsorbing the water content first and the molecular sieve mainly undertaking the adsorption of C02, CmHn, etc.
The air separation process of Dear Air Separation equipment has been very mature, and small air separation unit and large air separation plant of the product specifications required by the