Question: Reasons for compressor blowdown
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As the title suggests, I would like to know what causes the discharge of waste from the compressor. Is it due to contaminants carried by the compressed gas, or are it contaminants generated by the lubricating oil? It seems that some information indicates that the lubricating oil also plays a role in this issue. I don’t use the compressor on a regular basis, so I’m not sure. Please advise, fellow users
Prevent liquid hammer. Waste discharge mainly involves the release of liquids. Including lubricating oil.
The medium used in some compressors is not of high quality; some liquid remains after compression. To prevent liquid slugging, an intermediate drainage mechanism must be installed
In the case of reciprocating pumps, it is to prevent cylinder collision; in centrifugal pumps, it is to prevent liquids from damaging the impeller
In my opinion, in the compression of process gases using piston compressors or centrifugal compressors, 1. due to changes in the gas conditions (such as a decrease in temperature or pressure in certain areas), the water vapor contained within the process gas will condense inside the compressor. 2. The process gas also contains some water vapor at the compressor inlet; although there is a steam-water separator before the compressor inlet, this separator cannot remove 100% of the water vapor from the process gas. So, water vapor is inevitable during operation, and over time some liquid water ends up inside. Piston compressors are available in oil-lubricated and oil-free versions; those with oil lubrication require oil removal filtration at the outlet. Piston compressors with oil lubrication contain a large amount of lubricating oil inside. Under normal operating conditions, these oils are not considered pollutants. As long as it is maintained at a certain level, that’s sufficient. Most buffer tanks for the gas at the outlet of compressors are equipped with drainage devices.