Nitrogen Purging

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Essential Nitrogen Purging Applications: Fast and Efficient Processes

Nitrogen purging is a critical component of the safe and controlled removal moisture, oxygen, or Hydrocarbons from pipelines, when pipelines and petrochemical or gas plants must be shut down for maintenance or decommissioned, and before starting up a plant. It is used where combustible, highly flammable, or hazardous materials will fill columns or pipelines during start-up. To prevent these from exploding under favourable circumstances, an inert gas is pumped in to displace the oxygen. For shutdown, the process is to ensure all flammable or hazardous compounds are removed prior to hot work or opening the system to the atmosphere

Nitrogen-Purging Methods

Various types are used, including pressurised purging that entails a pressure cycling . A second method entails displacement and a third, dilution purging and drying.

Why the Process Is Essential

Regular nitrogen purging of gas- or petrochemical-production facilities and refineries is essential while purging of gas, petrochemical, and other pipelines transporting combustible materials is necessary for maintenance work and the startup or decommissioning of plants. Nitrogen is effective in removing oxygen from the system, helping to eliminate the risk of fires during maintenance. It also removes moisture and reduces the condensation point in the system. It is an inert gas; as such, it is non-flammable and safe. Though other inert gases can be used in the process, nitrogen is more affordable than most. The process is straightforward and ensures a safer operating environment.

When it is necessary:

  • Removal of pipelines and equipment from service.
  • Replacement of pipes.
  • Maintenance on a section of the system.
  • Where welding or hot work is necessary.
  • When gas or fluid changes must take place change of service.
  • When heat must be applied during the repair of the system.
  • Where users or workers will be exposed to hazardous substances in the system.
  • With the start-up of a plant or gas system to remove oxygen from the pipes.
  • With decommissioning a plant to ensure clean pipes and thus safety when no longer functioning.

Essential Precautions Before and After Nitrogen Purging

Provisions must be made for emergencies. This includes training employees on the procedures to follow, should an incident occur. Every person involved in the process must be well-trained and aware of the risks. Tests should be performed before and after the process by the relevant authorities. The nitrogen must be pumped into the system at a pressure and rate that is within the maximum pressure allowance for the system or pipeline, according to the manufacturer’s specifications.

Important Safety Aspects

The termination or outlet point must point away from and be some distance from the inlet – and people. Purging must be done according to the applicable environmental regulations, rules, and standards. Where it is done before the construction of a plant or installation of a pipeline, the manufacturing methods must be studied to ensure that the process followed will be safe and effective for the particular project. Complete records must be kept of the process and these details be available for maintenance activities and submission to the relevant authorities.

Get in touch for more information regarding nitrogen purging of gas or petrochemical plants, pipelines, and process systems. Our service offering includes the usage of mobile liquid nitrogen tanks, pumps, and vaporisers to reduce decommissioning and recommissioning times. With our equipment and expertise, we can help plants save considerable time performing these critical tasks.

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