What Is Nitrogen Purging? – Procedure and Equipment Used

A significant number of industrial processes are moisture-sensitive and require an oxygen-deficient environment to ensure the quality of their final products is not altered. Damage resulting from water vapor and oxidation is another serious challenge faced by many industrial manufacturers.

To tackle these problems, nitrogen purging is routinely incorporated in relevant processes.

What Is Nitrogen Purging?

Nitrogen purging is an industrial process where unwanted gases and other impurities are eliminated from a manufacturing system environment using nitrogen gas. Due to its inert properties, nitrogen can be used to effectively displace oxygen and other pro-oxidative gases from industrial processes without reacting chemically with the substrates.

Why Nitrogen Purging Is Required?

The benefits of nitrogen purging are numerous, but the most crucial reasons for nitrogen gas purging are to prevent chemical alteration of products and to prevent moisture-related equipment damage or even combustion.

A lot of industrial manufacturing processes could be adversely affected when conducted in the presence of moisture or oxygen-rich air. The oxidative damage caused by these unwanted impurities will diminish the quality of the final products with costly implications for profitability. Oxygen-sensitive operations integrate nitrogen purging equipment to prevent unfavorable manufacturing conditions.

Applications of Nitrogen Purging Systems

Nitrogen gas purging is currently being used across a range of industrial manufacturing processes, and purging is one of the reasons the industrial use of nitrogen is so common. Outlined below are some key uses of nitrogen flushing procedures in different applications.

• Brewery purging headspaces to extend the shelf life of beer
• Nitrogen blanketing for ships, tankers, and potentially combustible environments
• Nitrogen purging for transformers and volatile electrical environments
• Purging organic compounds in the chemical/petrochemical industries
• Toxic gas elimination in process chambers (e.g. sputtering tools)
• Pipeline drying and purging to limit oxygen concentrations – learn more about NiGen’s pipeline maintenance services.
• Modified Atmosphere Packaging with food-grade nitrogen in food production and packaging plants to remove moisture, oxygen, and other gaseous impurities
• Metal fabrication where N2 purging systems are used to eliminate compounds that might affect weld quality

4 Nitrogen Purging Systems

Different nitrogen purging systems are available for use, but the final choice of N2 purge system depends on individual operator preferences and requirements. Four key nitrogen purging system types are described below.

Displacement Purging with Nitrogen Gas

This technique is ideal for equipment with straightforward cross-sections (like pipelines). The procedure is simple to conduct. A cleaning component known as a “pig” is driven through the lumen of the equipment being cleaned using pressurized nitrogen gas. During the pigging procedure, the pig and gas pass through each pipe channel, purging the interior and removing gaseous and particulate impurities.

Dilution Purging with Nitrogen Gas

Dilution purging involves combining gaseous nitrogen with the gas needed to be eliminated. The mixture is then removed through an outlet point situated as far from the gas inlet as possible. This method of nitrogen purging is effective with both simple and complex systems with varied cross-sections such as kilns, reactors, and columns.

Pressure Liquid Transfer

The pressurized liquid transfer method is useful for purging systems with space constraints. This method is used to conduct liquids without using an external pump. The nitrogen gas used to drive the fluid motion will equally pressurize the headspace and purge the vessel. This technique of purging significantly reduces the risk of oxidation associated with liquid transfer between two process tanks.

Pressure-hold Vacuum Method

For procedures where a straight flushing action of nitrogen is not suitable, process vessels can be pressurized with nitrogen. This method is usually used on equipment with a single vent. Once the contents of the vessels have combined with the pressurized nitrogen, dilution and venting follow. This process is repeated as required to purge the vessel to a satisfactory level.

Nitrogen Purging in Pipelines

Pipeline purging with nitrogen gas is a critical component of natural gas line commissioning for flow lines. This procedure is necessary to eliminate oxygen, water vapor, and other impurities that are retained within a newly laid pipeline network. Failure to eliminate these substances will alter the quality of fluids being transported through the flow lines.

Nitrogen purging is a pretty straightforward procedure where the pressurized gas is forced through the lumen of the selected pipelines forcing out all gaseous and particulate impurities.

Safety Tips for Pipeline Purging

Nitrogen purging in an industrial setting is not without risks. To safely conduct pipeline purging operators should take the following steps:

• Ensure meticulous instruments/apparatus handling
• Properly train and brief all personnel on how to safely perform their duties
• Designate emergency protocols for shut down, and personnel evacuation with the provision of multiple points of egress
• Mandatory use of personal protective equipment by all personnel involved in purging operations

NiGen Offers Trusted Nitrogen Purging Services

Over the last decades, NiGen has been providing the very best nitrogen generation solutions suited to various industrial process needs. We offer cost-effective on-site nitrogen generators to a broad range of industries. If your needs are temporary, ask us about our nitrogen generator rentals.

Contact us today for a quote or specifications about our products and services.