From Ambient Air to High-Pressure Nitrogen: How Nardi Boosters Help Make It Happen
- Apr 18
- 3 min read
Recently, Nardi Compressori assisted with the installation of two Nardi BON2-55-350 C high-pressure boosters at a nitrogen generation plant. We wanted to share this project with you, to take a moment to describe the difference between a compressor and a booster, and how our BON2 units work in conjunction with other equipment that generates up to 95% high-pressure, high-volume nitrogen at this facility.
What is a Booster?
Unlike a compressor that takes in air at atmospheric pressure and compressors it, a booster takes an already compressed gas source and further increases the pressure. In the case of the BON2 series, our high-pressure boosters take gas from a pressurized source (0.05–150 bar / 0.7–218 psi) and recompress it up to 250 bar (5070 psi). At this particular installation, nitrogen is used for plastics manufacturing.
The Nitrogen Generation Process
Nitrogen generating systems come in many shapes and sizes, from standalone low-volume, low-purity units to large industrial installations requiring multiple components. The system shown in the above video requires a large volume of high-pressure nitrogen at purity levels up to 95%. This high demand requires a multi-system process. Viewing the video from start to finish (from left to right in the production room), you will see the following equipment:
Rotary Screw Compressor
The system begins with a rotary screw compressor that draws in ambient air and compresses it to approximately 9.7 bar (141 psi).
Storage Vessel
Compressed air feeds into a storage vessel, which serves two purposes: it cools the air and buffers the flow to ensure a steady, consistent supply to the downstream equipment.
Refrigerated Dryer & Filtration
From the vessel, air passes through a refrigeration dryer that chills the airstream to a pressure dew point of 3-5°C (37-41°F), condensing and removing moisture. The dried air then passes through a filtration stage, exiting clean and ready for gas separation.
Nitrogen Generators
Three (3) membrane nitrogen generators receive the filtered air. Inside each generator, thousands of polymeric hollow-fiber tubes carry the airstream. The tube walls contain nanoscale pores that act as a molecular filter: oxygen (O2) molecules and argon (Ar) molecules are small enough to permeate through the tube walls and are vented to atmosphere, while nitrogen (N2) molecules are too large to pass through and continue forward as the product gas. The result is a nitrogen stream delivered at approximately 8.5 bar (1233 psi), with the oxygen/argon byproduct safely purged at near-atmospheric pressure.
Buffer Vessel
The nitrogen flows into a buffer vessel that stabilizes supply pressure for the filling stage. A pressure regulator limits flow to the booster compressors at a maximum of 15 m³/h (8.8 cfm). Any nitrogen volume above that cap bypasses the boosters and goes directly to low-pressure delivery.
The regulated nitrogen feed enters a two-compressor boosting stage.
Nardi Compressori BON2-55-350 C Boosters
Two (2) BON2-55-350 C high-pressure booster compressors operate in a lead/lag configuration, running one at a time in alternation. The active unit compresses nitrogen to the target fill pressure and charges two racks of 16 cylinders (50-liters each). When both racks reach full pressure, the active booster stops and stands by. When cylinder pressure drops to 250 bar (3626 psi), the system restarts, with the lag unit rotating into the lead role. This alternating duty cycle distributes run hours evenly across both machines and ensures continuous availability.
High Pressure Storage Racks
The final nitrogen product is stored in two (2) racks of 16 high-pressure cylinders with a capacity of 50-liters each. This means that at the working storage pressure (250 bar / 3626 psi), the storage system can hold about 380,000 liters of 95% nitrogen (=14,126 cu ft or 380 m³).
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