Argon or Nitrogen. Which is Best for Your Application?

AArgon or Nitrogen. Which is Best for Your Application? - laser cutting image - Parker Balstonrgon and nitrogen are quite similar in inertness, but are vastly different in cost, both economic and environmental.

Argon, the noble gas

Argon is the most common gas in the atmosphere besides Nitrogen and Oxygen. Argon is a noble gas (like helium) which means that it is completely inert. Argon will not readily react with any other substance. Thinking back to your chemistry classes you’ll recall that the noble gases are unreactive because they have a full outer shell of electrons. Those electrons are tightly held and won’t be shared with other compounds. That makes Argon a good choice for blanketing of items like wine and sensitive chemicals but at a high cost.

Although argon is the third most common gas, it only makes up about 0.9% of the atmosphere. Commercially it is available as a by-product of industrial air separation. This is the only commercial source of Argon.  Since it is such a small percentage of the atmosphere Argon is many times more expensive than Nitrogen.

Nitrogen, the unreactive gas

On the other hand, nitrogen is not a noble gas. Two nitrogen atoms make up the nitrogen molecule (N2), so it has no free electrons like Argon and thus the same properties of a noble gas under nearly all uses. Indeed, nitrogen, which makes up 79.1% of our atmosphere, is very unreactive. Therefore, the relatively commonplace nitrogen exhibits the same properties of argon but at much less cost. Nitrogen is 88 times more abundant than argon. That means that the energy to produce a pound of nitrogen is 88 times less than the energy to produce a pound of argon. Argon production and distribution creates a large carbon footprint.

For most users of nitrogen gas, on site air separation using pressure swing adsorption or hollow fiber membranes reduces the cost of nitrogen even more than relying on an air separation factory. On site gas generation also minimizes CO2 emissions by eliminating diesel truck deliveries of bottled or liquid nitrogen.

Argon versus Nitrogen

One advantage of argon is its heavy weight. Argon has a density of 0.1 lb/ft3 and nitrogen is 0.07 lb/ft3 or about 40% heavier per cubic foot than nitrogen. Therefore, argon will tend to sit on top of a liquid column and not readily diffuse with air. For blanketing applications, determining how long a blanket of argon will stay in place is not a trivial task as it depends on temperature and movement of air above the blanket. Also argon is invisible so the user cannot easily determine when to replenish the blanket. Therefore, nitrogen is used because its low cost allows for continuous purging that would be uneconomical with argon.

There are two instances where argon is superior to nitrogen. Arc welding, where nitrogen becomes reactive in the presence of the electric arc, and in window insulation where argon has a much lower thermal conductivity than nitrogen. In almost all other uses of the gases, nitrogen is the better choice.

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This post was contributed by the Gas Generation Technology Team - Parker Industrial Gas Filtration and Generation Division.




Related articles on this blog:

How to Blanket a Chemical Tank Using a Nitrogen Generator

Why Nitrogen Is Better than Argon for Wine Production

How to Select an On-Site Nitrogen Generator

Nitrogen Gas Generators Save Winemakers Time and Money

How to Prevent Contamination & Corrosion in Demineralized Water Storage Tanks

Reduce Laser Cutting Costs With On-Site Nitrogen Generation

Modified Atmosphere Packaging with a Nitrogen Generator

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Comments for Argon or Nitrogen. Which is Best for Your Application?

Rachelle Karpeles
Hi, Can you please explain why bags panel or such in when nitrogen gas is used to extend shelf life in a food product?
An example is a bag of sunflower kernels that have been roasted in canola oil, then a 10 oz bag is nitrogen gassed. The gas extends the shelf life. I am not sure why or how it extends the shelf life, but if you look at the bag, over a 6 month to a year period, the bag sucks in and panels. Can you please explain why this happens?
Thanks Rachelle
David Connaughton
Hi Rachelle,

Thank you for submitting your question about my blog post. We love to hear from our customers.

Nitrogen extends shelf life of products because it displaces oxygen. Oxygen causes oxidation of compounds in the food. The oxygen sensitive compounds impact color, flavor, aroma, etc. In the case of sunflower seeds, oxygen hastens the rancidity of the canola oil and other compounds in the seeds. Over time, the nitrogen permeates out through the plastic bag and there an equilibrium of pressure and purity is achieved among the inside of the bag and the atmosphere outside the bag. Thus, the bag deflates. This is the same process that happens to a helium balloon. Over time, the helium in the balloon permeates out and leaves the balloon deflated.
Amer Jaradat
Are we can use Nitrogen generator PSA in the pharmaceutical applications although the nitrogen generator outlet contains mixture of nitrogen and argon up to 1.4%? Are there problems?
David Connaughton
There will be no problem that we are aware of with a small percentage of Argon. Argon and Nitrogen are both inert gases and unreactive under most conditions.

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