Nitrogen Purging

To nitrogen purge means the replacement of an atmosphere of an undesired composition in an enclosure by another atmosphere of required composition. There is usually some ultimate objective when purging, such as rendering a vessel safe for receiving a hydrocarbon product or for handling a reactive material. To achieve this there is an immediate objective of adjusting the vessel atmosphere composition to have, in the example mentioned, a maximum allowable oxygen concentration.

There are four main types of purging:

- Displacement Purging. Suitable for pipeline and Open systems
- Dilution Purging. Suitable Continuous replacement until desired oxygen content is reached Used in an open-ended system where the exhaust can be continuously vented to atmosphere
- Pressure Cycle Purging. Suitable to Used extensively for closed systems. This technique involves several pressurizations