SERVICES > Pre-Commissioning / Commissioning Services > Nitrogen Purging

Nitrogen Purging


Nitrogen purging is an industry standard technique for the replacement of a hazardous or undesirable atmosphere with an inert dry atmosphere. During the commissioning of a process plant, the replacement of air by purging with nitrogen is familiarly known as ‘oxygen freeing’ or ‘start up purging’. During a turnaround, the replacement of a hydrocarbon atmosphere with nitrogen is familiarly known as ‘degassing’ or ‘shutdown purging’.


The two most common methods of purging are displacement and dilution. The geometry of the process system determines which method is used. For simple systems, displacement purging is usually more effective in terms of time and cost but, for more complex systems, dilution purging is used.


Alstern Technologies has a large fleet of nitrogen equipment. Our nitrogen testing capability extends to pressures of 1,000 barg (14,500 psig), and with flowrates limited only the supply of liquid nitrogen. With over 15 years of experience, Alstern Technologies has established as one of the leaders in specialised nitrogen related services, and enabled our clients to reduce turnaround schedules, improve operating efficiencies, and implement the highest standards of site safety.


Alstern Technologies’ nitrogen pumps are rated at 180,000scf/hr and the majority of our LN2 tanks can be stacked. Our pumps are soundproofed to 80dB(A) and built to the highest modern standards, meeting all current legislation.