N₂ Membrane System

An N₂ membrane system produces nitrogen by separating nitrogen from compressed air.

The system typically consists of:

Diesel fuel tanks → Air compressors → N₂ membrane → Pipeline

N₂ membrane systems available for pipeline applications are commonly in the range of 2,000–3,000 CFM, depending on the supplier and configuration.

A key planning assumption is that the nitrogen output can be approximately 50% of the compressed-air input, although the actual recovery and nitrogen purity depend on the membrane system and operating conditions.

Example

If the compressors provide:

4,000 CFM compressed air

and the membrane system produces approximately 50% nitrogen recovery:

4,000 CFM × 50% ≈ 2,000 CFM N₂

A typical air compressor used in these applications may provide approximately 1,000 CFM, depending on the equipment specification.

Therefore, achieving approximately 4,000 CFM of compressed-air input could require approximately four 1,000-CFM compressors.

Multiple membrane units can also be operated in parallel when a higher nitrogen flow is required or when the inspection configuration requires more than one NGU.

Typical membrane arrangement

Diesel tanks provide fuel to the diesel-driven air compressors.

The compressors supply compressed air to the N₂ membrane units.

The membrane separates nitrogen from the compressed air and delivers the nitrogen to the pipeline.

The final configuration depends on the required nitrogen flow, pressure, purity, pipeline volume, target speed and number of runs.

Important: The 50% recovery figure is a planning assumption. Actual membrane performance should always be confirmed with the equipment supplier because nitrogen recovery, purity, pressure and flow depend on the specific membrane package and operating conditions.