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Screw compressors (referring here to oil-injected screws) face issues such as wear and corrosion, bearing and rotor failure, reduced lifespan, and air quality problems. Common problems with screw air compressor oil: -- Higher compression chamber temperatures increase the risk of rotor and bearing failure. The oil film thins, leading to wear issues. It also accelerates the oxidation/aging of the lubricating oil, resulting in the formation of varnish layers and reducing the lifespan of the oil. This lowers the efficiency of the compressor and increases energy consumption. -- Tendency to oxidize easily. Lubricating oil spray enters the compression chamber in a mist form, increasing the surface area and allowing it to mix thoroughly with the hot compressed gas, which facilitates oxidation. The oil is repeatedly heated and cooled, making it susceptible to metal-catalyzed oxidation. Dust and impurities in the air source can contaminate the oil, with these impurities catalyzing its aging and deterioration. The main forms of oxidation in screw air compressor oil are: – Varnish layers on the screw surfaces; this makes it difficult for an oil film to form, exacerbating wear and potentially causing the screws to get stuck. – Sludge: It blocks oil pumps and filters, disrupts the flow and lubrication properties of the oil, and leads to rusting and wear of compressor components. – Increased viscosity: Oil should be replaced if the viscosity increases by more than +15%. Increased acid value: This causes corrosion and shortens the interval between oil changes. Generally, there is no issue with carbon buildup – it is moisture condensation that causes corrosion problems; this leads to emulsification, reduces lubrication performance, shortens the lifespan of lubricant, and exacerbates wear issues. Rusting problems (caused by dust, compressed air sources, etc.) also result in wear and corrosion, shortening the lifespan of rotors and bearings as well as accelerating oxidation and reducing the lifespan of lubricant. There is also the issue of foam, which makes oil separation difficult, increases the oil content in the air, raises fuel consumption, and reduces lubrication performance, thereby accelerating wear of compressor components. Issues related to air quality/oil content are another concern. The quality and performance of oil separators, as well as foam problems, are important factors to consider. The lubricant used in screw compressors must meet certain performance requirements; an adequate amount of lubricant is necessary to form a sufficient oil film for lubrication, and lubrication performance is not generally a major issue (in general, wear problems do not arise due to insufficient lubrication properties of new oil). Good antioxidant properties are needed to reduce the formation of varnish and sludge, which can lower compressor efficiency. Anti-emulsification properties are essential to prevent the formation of emulsions, which can damage lubrication performance and accelerate oxidation. Low volatility is important to reduce fuel consumption and the oil content in the air. Anti-foaming properties help to avoid a decrease in lubrication performance and difficulties in oil separation. Rust prevention is also crucial, especially when moisture is present. Oil removal in compressor systems is another important aspect – using lubricant to operate compressors means that oil removal at the downstream stage is also very important. Most manufacturers opt for simple oil removal filters or activated carbon filters, but for those who require higher stability and quality in compressed air, it is recommended to use specialized equipment for oil removal from compressed air. Currently, catalytic oxidation devices can be used for this purpose.