On-site nitrogen generators are becoming the mainstay due to their applications in various industries. Nitrogen generators have significantly reduced the use of nitrogen gas cylinders, especially in large-scale facilities. Hence, cutting down on the multiple downsides of gas cylinder usage, such as frequent replacement, having to switch cylinders, waiting for a shipment of cylinders to arrive, delays work.
On-site nitrogen generation is a process that is heavily applied in a long list of industries from the medical, food/beverage, electronic industries, and a host of others. We would look at some of these industries but first, let’s explore how nitrogen generators can perform their functions.
Nitrogen Generators: How Do They Work?
Most nitrogen generators work under the principle of adsorption. When a solid surface comes in contact with a gas or liquid, molecules from the gas or liquid collect on the solid’s surface. This phenomenon of collecting gas or liquid molecules on the solid’s surface is known as adsorption. A substance that accumulates on the solid surface is known as adsorbate, and the solid surface on which it occurs is known as an adsorbent.
Nitrogen generators work by taking in air from the atmosphere, mostly about 78% nitrogen, 21% oxygen, and releasing nitrogen of higher purity in the following two methods.
Pressure Swing Adsorption Technology
A Pressure Swing Adsorption (PSA) Nitrogen Generator employs a Carbon Molecular Sieve (CMS) to separate nitrogen molecules from compressed air. The CMS absorbs the oxygen under high pressure to produce pure nitrogen as output.
Membrane nitrogen generation technology operates by employing a concept known as selective permeability. Membrane generators use porous hollow fibres that permit different levels of gas to pass through the membrane. Compressed air is forced through the membrane, and the molecules of oxygen are trapped, thereby realizing nitrogen of higher purity.
Industrial Application of On-site Nitrogen Generators
On-site nitrogen generation is a valuable process that is widely applied in different industries, as earlier mentioned. Some of the ways and the industries they are used are as follows.
In the food industry, nitrogen generators are widely employed to provide nitrogen for food and beverage packaging. The nitrogen displaces oxygen, which is the culprit that contributes to food spoilage. Notice how apples turn brown after a bite has been taken from them? That’s oxygen in the air acting on the sugars. Replacing oxygen with nitrogen helps stop that process called oxidation. Ever wondered what the air in potato chip bags was for? That air is nitrogen gas; it preserves freshness, prevents aerobic microorganisms’ growth, and protects nutrients.
Beverage Processing Industry
Similar to the food industry, on-site nitrogen generation is used to produce nitrogen for preservation purposes. For instance, in the wine industry, nitrogen allows the wine to be stored longer while protecting its acidity, colour, aroma, and natural flavour.
Nitrogen is also insoluble in water; this makes its use for transferring wine ideal. After washing, the bottles are dried with nitrogen rather than regular air because nitrogen dries faster. Nitrogen is also used in other beverage industries for beer bottling, canning, dispensing, etc.
In this industry, nitrogen gas is used to replace unwanted atmosphere hazardous to manufacturing conditions. Once again, nitrogen is used because it is inert, and it reduces oxygen, which can act as a catalyst for combustion leading to low product quality. It is also used to preserve the sterility and cleanliness of the pharmaceutical environment.
Packaging in the pharmaceutical industry is done using nitrogen via a process called nitrogen purging. It is used to preserve the content just like in the food industry,
There are various nitrogen applications in industries like electrical, electronics and power, fabrication and steel, oil and gas, to name a few. Its purposes range from purging and inerting to product transfer and packaging.
Some of the manufacturing industries that require on-site nitrogen generation include:
- Oil and Gas Industries:Nitrogen provides inerting for oil refining, hydrogen purification, natural gas dehydration, etc.
- Fabrication Industries:In welding, it prevents the formation of oxides and other unwanted compounds on workpieces
- Steel Industry: Prevents oxidation of steel and its alloys
- Product Transfer: Prevents contamination of products to be transferred if they contact air or water.
- Electronic Industry:Contamination of circuits, transistors, and diodes is prevented using nitrogen.
There are several applications of nitrogen in the military. Nitrogen is used for:
- Inerting aircraft fuel tanks
- Waterproofing and defogging essential optical equipment like binoculars, cameras, night vision goggles, telescopes, etc.
- Replacing oxygen in instruments with nitrogen to reduce their susceptibility to fogging.
- Prevention of mould and fungus growth is achieved with nitrogen purging. Because nitrogen is a dry gas, it does not contain moisture that supports the development of microbes.