Under what circumstances is pipeline drying with nitrogen performed?
Thread Content
Under what circumstances is pipeline drying with nitrogen performed?
Pipeline drying in natural gas stations is a common practice; it prevents residual liquid water in the pipelines from reacting with the small amounts of acidic gases present in natural gas to form acidic substances, which can cause severe stress corrosion inside the pipelines. This, in turn, affects the service life and reliability of the pipeline system.
Corrosive pipes that have been out of use for a long time, such as carbon steel pipes that have not been in use for an extended period, and pipelines whose internal medium is circulating water, steam, condensate, etc. After long-term disuse, the water must be drained, followed by purging and drying with nitrogen, after which a slight positive pressure can be maintained.
Before first use, purge with nitrogen and dry it to ensure that there are no impurities, particles, moisture, oxygen, etc. inside the tube. In cases where a pipeline remains idle for an extended period but needs to be put into use promptly in the future, it may be advisable to seal it with dry nitrogen to prevent corrosion; during regular inspections, the pressure of the nitrogen used for sealing as well as its moisture content should be monitored.