Operation and maintenance of compressors in low-temperature environments

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As the cold winter sets in, especially in the northeastern region where outdoor temperatures drop to below minus 20 degrees Celsius, what impact will this have on compressors? 　　Harbin’s winters are cold and long; nearly six months of the year are spent in winter. In winter, the average temperature is below minus twenty degrees, which poses a significant challenge to the operation and maintenance of compressors. Although in some companies the compressor units are installed indoors where heating is available, so that there are usually no issues, in many other companies the compressors are placed in cold sheds without heating, or in corners of the production area where no heating facilities exist. 　　In the Heilongjiang region, the lowest temperatures near Harbin are in the low twenties degrees below zero, and this condition persists for a long time. Further north, in the Daxinganling and Xiaoxinganling areas, the temperatures can drop to over forty degrees below zero. The author visited the Heihe Coal Mine in winter and saw that the compressors there were located in unheated sheds, with low temperatures underground as well; the compressors did not have any heating support. In these locations, since the equipment is constantly in operation and the internal circulation is normal, just like in the human body where blood keeps circulating, compressors generally do not fail due to cold temperatures. However, this does not mean that cold has no effect on the compressor. On the contrary, cold weather can cause significant problems for compressors, and this should be of concern to us. 　　Conventional compressors have certain requirements regarding the temperature of the operating conditions; therefore, in cold regions, especially during outdoor operations, specialized compressors that can withstand low temperatures are needed. For example, in Tibet, freeze-resistant compressors are in operation and being used. However, under normal conditions, ordinary compressors do not have anti-freezing capabilities; in temperatures around minus ten degrees Celsius, most compressors can still function properly. This temperature can also occur in southern regions with relatively high temperatures, and in such areas, compressors basically have no heating support. 　　I. Cold air 　　When cold air enters the compressor, it comes into contact with high temperatures and generates a large amount of water vapor, which increases the burden on the systems used to filter this water vapor after compression. However, for customers who have low requirements regarding compressed air, a certain level of humidity in the compressed air is acceptable. In actual production, there are cases where some customers do not have post-treatment equipment, or where such equipment is not functioning properly or is out of use. After entering the air tank, the air passes through pipes to the production area where it is used by users; some of these pipes are buried underground, while others run exposed in the air. Laying exposed pipes in cold weather may result in the formation of moisture due to low temperatures; in some cases, this increased moisture can even affect the normal use of the system by users. 　　For example, in my company’s case, the cold compressed air has an increased humidity level, and this humidity has a certain impact on the processes used to produce aluminum products. If the surface of aluminum has too much moisture, it not only affects the hardness of the alloy but also facilitates corrosion of the metal surface, resulting in a certain rate of defective products. Recently, the waste rate in our company has remained high. It may not be caused by the cold and humid conditions, but there is no doubt that humidity has a corrosive effect on metal surfaces. 　　In mines, humid compressed air can affect the force exerted by pneumatic hammers at the working surface; it may cause slight variations in the strength of these hammers. Such effects are sometimes negligible and do not interfere with the normal use of the pneumatic hammers. 　　In cement plants, the compressors I saw were stored in outdoor cold sheds, while the compressed air pipelines were installed at high heights outside. At low temperatures, the humidity level of compressed air is higher than usual; although this does not have a significant impact on cement production, it reduces the lifespan of the compressors themselves. 　　In the food industry, I have also seen compressors operated without heating. While this setup is not particularly hazardous, cold air can cause slight changes in the quality of the gas inside the compressor. 　　The air that comes into contact with the compressor is drawn in directly through ventilation ducts from the outdoor vents of the station building; this air has a fresh quality in cold winters, but it also contains a high level of moisture. 　　II. Circulating water 　In compressors used in the northern regions, those that employ water cooling are generally compressors with a capacity of 20 cubic meters or more. Such compressors are designed for large areas of use, and they are typically employed by large and medium-sized enterprises as well as other factories with high gas consumption needs. And these factories usually have their own circulating water pump stations, which enable them to handle the relevant water on their own; the cooling water can be reused, thus avoiding waste of water resources. 　　In companies that use circulating water, it is generally shared among many processes, with compressors accounting for only a very small portion of the consumption. In the compressor section, the temperature of the circulating water is closely related to its water quality. In winter, the temperature of the circulating water is much lower than in summer, which is very beneficial for the cooling effect of the compressor. In summer, the water temperature is relatively high; some compressors even require an electric fan to be turned on for cooling. In winter, this phenomenon naturally doesn’t occur. 　　Circulating water generally flows through underground pipes. Although the temperature of the pipes and wells is quite low, it isn’t low enough to cause the pipes to freeze. Therefore, under normal circumstances, circulating water pipes do not fail due to cold weather. Moreover, generally speaking, the diameters of the circulating water pipes are quite large; even when the circulating water is discharged, its temperature is usually around 20 or 30 degrees, which allows it to withstand certain levels of cold. 　　Due to the cold, there is a lower likelihood of the circulating water pipes freezing. In winter, given the low outdoor temperatures, the cooling effect of the circulating water is better than in summer. Moreover, the circulating water passes through the cooling tower, which operates in the natural outdoor environment. Therefore, the cold weather is highly beneficial for cooling the circulating water, as well as for cooling the compressor. 　　III. Lubricating oil
The oil circuit system is a crucial component of the compressor’s circulation system. During normal operation, friction occurs within this system due to the rotation of the machine; the heat generated by this friction causes the temperature of the lubricating oil to rise. At the same time, the oil temperature in the compressor oil circuit system also increases. To ensure that the temperature of the lubricating oil can be reduced, water cooling and air cooling are generally used to cool the oil circuit system. In winter, due to the low outdoor temperatures, the temperature of the circulating water is also low. This significantly improves the cooling effect on the oil system. However, it’s not to say that problems can’t occur in lubrication systems at all. In compressors located in outdoor cold shelters, for instance, a normally operating compressor generally has no major difficulty in withstanding low temperatures, thanks to the continuous circulation of lubricating oil. However, for spare equipment or equipment that is not operated on a regular basis, when it is restarted in a cold shed with temperatures close to those outside, the oil circuit may experience lubricant condensation due to the low temperatures, which can lead to problems during startup. This requires inspecting the oil circuit system to see whether the lubricating oil in it is in a normal condition. 　　Regarding the storage of lubricant, it is generally required to be kept in a heated indoor area; if stored outdoors, the lubricant may freeze due to low temperatures, making it unavailable for use when needed. Lubricating oil should be stored separately from other materials, as it is a flammable substance. Storing it together with other items may lead to contamination or malfunctions caused by those items. 　　It can be seen that low temperatures in winter have both positive and negative effects on compressors; therefore, it is necessary to pay close attention not only during the operation of compressor equipment, but also during its maintenance, as well as when storing spare parts. Pay attention to how to operate and maintain compressor equipment in low-temperature conditions, so as to ensure the safe and normal operation of production. The content is from the internet