Answer:
(1) The following factors should be considered when selecting lubricants:
1) The working conditions (i.e., working conditions) of the actual use of the mechanical equipment;
2) The designation or recommendation of the mechanical equipment manufacturer and the lubricant manufacturer;
3) Consider the economic and safety factors of the user.
(2) Methods for selecting the right lubricant:
1) From the user's economic point of view, the main purpose of selecting synthetic oil is to save money. Compared with mineral oil, synthetic lubricants have excellent comprehensive properties, such as good high-temperature oxidation stability, low carbon residue, high flash point, low volatility, good low-temperature performance and lubrication performance, and a wide operating temperature range. The use of synthetic compressor oil can significantly extend the oil change cycle (extended by 8 to 10 times), reduce the replacement of filters and oil-gas separators, and reduce the number of replacements of mechanical parts such as bearings and seals. This not only reduces material costs, but also reduces labor costs. In particular, the use of synthetic ester oil can significantly reduce sludge, precipitation, and carbon deposition.
2) From the perspective of safety factors, compressors used to compress and transport air, chemical gases and other media used mineral lubricants in the past. This was mainly because reciprocating compressors often caught fire and exploded, which attracted people's attention. In the analysis of the causes of the accidents, half of them were due to the violent oxidation of lubricants in contact with high-temperature and high-pressure air, resulting in the generation of coke that blocked the outlet valve and outlet pipeline. Solving the problem of how to inhibit the degradation and precipitation of lubricants at high exhaust temperatures has promoted the development of synthetic compressor oils. Years of practice have proved that synthetic compressor oils can meet the performance requirements of various compressors working under harsh conditions such as high temperature, high pressure, and high speed, and can work safely and trouble-free with a lifespan several times longer than that of mineral oil.
3) From the perspective of environmental protection, due to the low volatility of synthetic air compressor oil, the oil brought out by compressed gas is reduced to a very low level, thereby reducing pollution to the atmosphere. At the same time, synthetic diester air compressor oil has biodegradable properties, which also reduces pollution to the environment. It is a green lubricant that meets environmental protection requirements, and therefore has attracted much attention and adoption.
4) From the perspective of the working environment of the air compressor, mineral oil type air compressor lubricant has a short service life and is prone to carbon deposits. This is mainly because mineral oil contains more heavy components. It is best used in screw air compressors where the environmental conditions are very harsh and the lubricant must be changed frequently.
For most screw air compressors, if the operating environment conditions are relatively mild, hydrocarbon synthetic air compressor lubricant should be used. This is because hydrocarbon synthetic compressor oil has a lower tendency to carbon deposits and can be used for a longer time. If the screw air compressor uses mineral lubricant, the oil needs to be changed about 2000 hours, while the oil change time can be extended to 6000~8000 hours if hydrocarbon synthetic air compressor lubricant is used.
