Compressed nitrogen and compressed air both power critical industrial systems, but their different physical and chemical properties lead to important distinctions in compressor design, safety, and packaging.
Fundamental Differences Between Nitrogen and Air
- Nitrogen is a pure gas.
- Air comprises nitrogen, oxygen, argon, and trace gases.
- Inert Behavior: Because nitrogen is inert, it does not react like oxygen. Compressing it demands equipment built to resist contamination, moisture, and degradation over time.
- While many compression principles overlap, equipment selection, safety measures, and system packaging must adapt to each gas’s unique traits.
- Compressing nitrogen is simpler than compressing air since there are no other gases to consider.
Common Industrial Uses for Compressed Nitrogen
Nitrogen serves many roles across industries that demand high purity, controlled environments, or inert atmosphere:
- Electronics: Nitrogen is used to manufacture electronic components (semiconductors, LCDs, and computer chips) to create a controlled environment free of oxygen and other impurities. Those gases can significantly damage electronic components’ capabilities. This is a rapidly expanding industry requiring increasing demand for pressurized nitrogen.
- Chemical: Nitrogen is also required for many processes, including the production of ammonia and fertilizers. Nitrogen is used to neutralize the potentially harmful effects of oxygen in chemical manufacturing operations through nitrogen blanketing. Nitrogen blanketing introduces nitrogen gas into a storage vessel that will be used to store chemical components or finished chemical products.
- Welding: Nitrogen acts as shielding to help improve the welding quality. It protects the weld from surrounding air, which contains moisture and other impurities that can negatively impact weld strength and quality.
- Food & Beverage: Nitrogen helps with packaging and preservation. Since nitrogen is an inert gas, it prevents oxidation and spoilage for food products such as potato chips, nuts, fruits, and dairy.
- Medical: Nitrogen is used in many intricate surgeries and therapy practices to freeze and destroy abnormal tissue growth. It is also used in medical imaging, like MRIs, to cool the equipment.
For many manufacturing applications, nitrogen is safer as part of the process because it is non-flammable and non-reactive.
Safety Considerations for Nitrogen Compression
When compressing nitrogen, there are some additional safety considerations for the compressor to avoid harm to the operator. Since 78% of the air we breathe is nitrogen, nitrogen is assumed to be not hazardous. However, breathing pure nitrogen displaces oxygen, which can cause dizziness, unconsciousness, or asphyxiation without warning. To mitigate this risk, nitrogen compressor systems often include:
- Clear Warning Labels/Instructions: Units will typically be manufactured with additional warning labels that warn of the possibility of nitrogen asphyxiation, particularly for confined spaces.
- Solenoid Valves: Additional solenoid valves may be used in the seal gas piping to prevent the flow of nitrogen seal gas to the compressor’s seals when the units are not in operation. This will prevent excess nitrogen leakage through buffered seals to the surrounding area and prevent nitrogen from being wasted.
These safety provisions are necessary because nitrogen's invisibility and lack of odor can mask danger until it’s too late.
Packaging And Design for Nitrogen Compressors
There are a few essential considerations when packaging nitrogen compressors compared to standard air compressors.
- Recycle Valve: While the design and operation can vary, recycling valves return nitrogen to the process instead of blowing the excess off into atmospheric air. This ensures the customer is not wasting any excess gas and saving money.
- Pressure Considerations: Nitrogen compressors must withstand higher pressure than normal air compressors. Nitrogen processes will typically have higher nitrogen inlet and discharge pressure resulting in compressor casings and coolers having higher MAWPs (Maximum allowable working pressure).
- Combination Machines: Packaging dual process machines that compress air and nitrogen not only help support two different processes but can cut capital and operation costs by having one machine instead of two separate machines for their process. It makes the installation and operation simple for end users in the long run.
Overall, nitrogen compression demands more robust hardware, precise control, and safety features tailored to its properties.
Which One is Better?
The main difference between nitrogen and air is the gas properties and the specific applications of these compressors. Nitrogen compressors can handle higher pressures, remove contaminants from gas, and work safely with the unique properties of nitrogen gas.
For additional information on nitrogen compressor and air separation applications, visit our air separation units or download our informational brochure!