How to select lubricate oil for compressor--lubricate oil types and properties
Types and properties of synthetic oil
Ester oil (diester and polyol ester), polyolefin (PAO), polyalkylene glycol (PAG) and silicon fluoride oil can meet the application requirements of most gas compressors, and are currently the most widely used synthetic lubricants for gas compressors. Recently, hydrocracking saturated hydrocarbon has been found to be an acceptable lubricant for compressors. Synthetic oil has unique physical properties, and is superior to mineral oil in temperature limit, viscosity temperature characteristics and volatility.
1). Temperature limit many lubrication problems solved by synthetic oil are related to temperature. In order to prevent water and other refrigerants from condensing in the compressor system, the working temperature of the compressor is higher than that of the general lubricant. When mineral oil is used, it is difficult to start compressor in field or unheated environment due to the gelling effect of wax and poor viscosity temperature characteristics. These problems can be avoided by selecting synthetic oil.
2). Viscosity temperature characteristics: compared with the viscosity temperature characteristics of mineral oil, synthetic oil can provide effective lubrication at the limit temperature. The viscosity index of synthetic oil is high, which provides high viscosity under high temperature operation condition, and the compressor is easy to start at low temperature. The synthetic oil with high viscosity during operation provides high volume efficiency for screw compressor.
3). Volatile synthetic oil has low volatility, which reduces oil compensation and prevents impurities from being brought into the next step. The vapor pressure of synthetic oil is smaller than that of mineral oil.