Nitrogen Generators

A nitrogen generator is a piece of equipment often comparable to the size of a kitchen refrigerator. Keep in mind that nitrogen generators do not generate nitrogen! Rather, these machines filter out the other molecules in the air such as carbon dioxide, argon, dust particles, water, and oxygen, and then dries the nitrogen gas. At the end of this process, a more concentrated and purer form of nitrogen remains.

There are two kinds of nitrogen generators: PSA (pressure swing adsorption) generators and membrane generators.

PSA (pressure swing adsorption) nitrogen generator. Using this type, air gets drawn in through an intake valve and travels to a carbon molecular sieve that has tiny pores across its surface. The sieve absorbs the smaller oxygen molecules while the nitrogen molecules, which are larger, move past this and are collected in the nitrogen receiver. Pressure and oxygen molecules are released. Simultaneously in another container, the cycle repeats itself to provide a gas flow into the nitrogen receiver. As a result, high nitrogen purity levels – up to 99.999 percent -- can be achieved.

Membrane nitrogen generator. With this type, pressured air flows from one end of the fiber membrane tube. Membranes house numerous hollow fibers that allow smaller oxygen molecules to escape through them when pressurized. Larger nitrogen molecules diffuse slower and remain in the fiber membranes collecting as natural gas. Fiber membranes function as a filter with no moving parts. Continual nitrogen generation is the result. This type of generator produces up to 99.5 percent pure nitrogen.

There are many additional advantages to on-site nitrogen generation, as compared to using bulk or bottled nitrogen. These include:

• Environmentally friendly and sustainable, energy-efficient approach to obtaining clean, pure nitrogen gas.
• Fast return on investment: The upfront cost of buying the nitrogen generator is typically recouped in a few years, and after that the cost of nitrogen gas is virtually eliminated because there are no recurring charges.
• Fewer transportation costs – no need to transport nitrogen from A to B. All done on-site.
• Increased reliability. Relying on nitrogen deliveries isn’t ideal. Production is halted until it arrives. On-site nitrogen generators allow you to produce nitrogen on-demand so you’ll never run out.
• And you will not be locked into a contract with an external company.

On-site nitrogen generators are commonly used in the following industries:

• Laser Cutting. When the cut of the laser needs to be excellent, nitrogen gas is used as the assist gas of choice. Ensures that the cut edge won’t be discolored, and that the heat dissipates quickly.
• Breweries. Nitrogen is an essential element in the malting, mashing, boiling, and fermenting processes occurring in a brewery! Cleans tanks between batches, helps move beer from one tank to the next; is injected into a keg before shipping/storing to help pressurize it; can be infused into beer (with carbon dioxide) during brewing to give beer a more complex taste.
• Food Packaging. Nitrogen is used to displace the oxygen in food packaging (like snack packages), ensuring that the food is kept fresh and doesn’t age or decay. This prolongs the lifetime of the food and ensures that it’s crisp when you open it!

Now let’s consider your bag of peanuts. To slow their aging process, nitrogen delays oxidation. This slow-down controls the peanuts’ fats and oils and increases the time they stay crisp and fresh. Inside the bags the pockets of space fill with nitrogen, pushing oxygen out of the bag and eliminating moisture and mold.

Nitrogen generators are used on-site in various manufacturing applications beyond beer and peanuts such as wine, potato chips, bird food, vegetables, and fruits.

For all these applications key decisions are having to be made about whether to use on-site nitrogen generators within the manufacturing facilities or have nitrogen bottles and tanks delivered to the facilities on a periodic basis.

A strong case can be made for using on-site generators because they reduce manufacturing delays, equipment storage space needs, and overall costs while increasing safety, reliability, and efficiency.

On-site nitrogen generators run 24-7 and give manufacturers access to nitrogen any time they need it. As such, manufacturers don’t have to wait for nitrogen bottle and liquid tank nitrogen deliveries, which can be delayed and sometimes cancelled.

The up-front costs to buy an on-site nitrogen generator could be a concern for some manufacturers. But in the long run they are likely to accelerate manufacturing processes, reduce waste, and cut costs. By investing in an on-site generation, a brewery could break even within the first two years of installation and, over time, save from 40-75 percent on overall nitrogen costs.