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Although oil-free compressed air is being used more and more widely these days, many manufacturers still opt for oil-lubricated compressors due to cost considerations. Regardless of the operating conditions, oil-lubricated compressors require some kind of oil removal equipment, so it is important to choose the appropriate oil removal equipment. Currently, there are few reliable methods for removing oil from compressed air. The methods reported for this purpose mostly involve the use of specialized oil-removal components to remove oil physically. This method is effective in removing oil droplets and oil mist from compressed air, but it is basically unable to remove molecular form of oil (hydrocarbons) in compressed air. Therefore, it is difficult to achieve an oil-free level using physical methods to treat oil-containing compressed air. According to the standard GB/T 13277.1-2008 (ISO 8573-1 eqv.), \"Compressed air – Part 1: Pollution control levels\", the oil content in compressed air is defined as the sum of liquid oil, suspended oil, and oil vapor. http://5b0988e595225.cdn.sohucs.com/images/20190515/7b99d86f769042ed95522d306c9b14f0.png Currently, the following effective methods are commonly used to remove oily impurities from the air: (1) Using cooling combined with filtration. It primarily takes advantage of the difference in the saturated vapor pressures of oil at different temperatures under certain pressure, to cause a phase transition from oil vapor to oil mist at low temperatures, as well as a transformation in which small oil mist particles aggregate into larger ones. (2) Activated carbon filtration. Taking advantage of the high specific surface area of activated carbon, oil impurities in compressed air are removed through adsorption. (3) Catalytic oxidation for oil removal. At a certain temperature, in compressed air, the oil molecules therein undergo a catalytic oxidation reaction with oxygen molecules on the surface of an oxidation catalyst, resulting in their complete conversion into carbon dioxide and water. Since the oxygen content in compressed air is much higher than that in oil, the key to carrying out this process lies in providing a site and appropriate conditions for the rapid reaction and conversion of oil and oxygen. Analysis of oil removal efficiency: (1) The method of cooling + filtration is used: Since the amount of oil vapor is determined solely by the temperature of the compressed air, cooling can be employed to liquefy the oil vapor, which can then be removed through filtration. In practice, however, since the filter elements cannot eliminate liquid oil droplets and oil mist 100%, the remaining droplets and mist rapidly vaporize back into oil vapor once the temperature rises; as a result, it is difficult to achieve a zero-oil level. (2) Activated carbon filtration: The service life depends on the amount of activated carbon used; its performance declines significantly over time. The activated carbon needs to be replaced frequently, and the replacement interval is greatly influenced by the oil content in the incoming fluid. There is a high risk of saturation, which makes it impossible to meet the gas requirements for continuous process operation. (3) Catalytic oxidation for oil removal: The oil removal effect remains constant; it is capable of removing oil mist and oil vapor in one go, with high efficiency. It is not affected by fluctuations in the oil content at the inlet, offering broad adaptability. Even in situations with high oil content, the principle of catalytic oxidation is utilized to enable deep oxidation reactions between the oils in the compressed air and oxygen on the surface of the catalyst, converting these oils into CO2 and H2O. CnHm + (n+m/4)O2→nCO2 + m/2H2O. The key to this entire process is the catalytic oxidation catalyst, which is a composite material obtained by combining an active substance with a carrier through complex processing; the surface of this catalyst features numerous pores in which a large amount of active substance is contained. This provides favorable conditions and a suitable environment for the occurrence of catalytic oxidation reactions, with the entire process being controlled by a high-precision control system, ensuring safety and stability. In cases where oil contamination in the compressed air system is severe, catalytic oxidation-based oil removal products are preferred, as they offer a more stable and reliable oil removal effect.