Nitrogen can be used for a myriad of applications throughout the manufacturing industry. Tank blanketing, nitrogen purging and gas shielding are all examples of applications where Nitrogen is commonly used. Due to its abundance in earth’s atmosphere, Nitrogen is is the gas of choice because of its availability and low cost.
In this application, the BS regulator is controlling the pressure of nitrogen being introduced into the tank to purge the undesired gas.
Nitrogen purging is the method of replacing undesirable or hazardous atmosphere with an inert dry atmosphere and it is one of the most common applications where Nitrogen is used in industry. Depending on the type of equipment used, there are different methods used in Nitrogen purging:
Displacement Purging
The replacement of the undesired gas by a purge gas without intermixing of the two. The volume of nitrogen required corresponds to the volume of the piping involved. In theory, displacement would be a simple, swift means of purging, but in practice it is impossible to introduce a gas into a piping system without intermixing with the gas already in the system. Displacement purging is used in very basic piping runs and geometries.
Dilution Purging
The reduction in concentration of an undesired gas by the addition of a purge gas, like N2. The amount of the undesired gas does not change, but as more nitrogen is added, the concentration of the undesired gas decreases. Dilution purging is used in more complex piping runs and geometries.
Continuous Flow Purging
The continuous introduction of purge gas at one end of a piping system, with continuous removal of the mixture of the two gases from the far end of the piping system. In simple systems, such as tubing runs, the displacement effect is almost absolute, with much of the undesired gas rapidly driven out at the exit end of the tubing.