Liquid nitrogen & cylinders vs nitrogen gas generation

Q: Are nitrogen gas generator safe?

Yes!As the generator does not add or take anything away from the atmospheric air, you could have one running in a closed room with no change to the overall content of the atmosphere. They also negate the need to store and move potentially dangerous high pressure cylinders on site.

Your business uses nitrogen? If it does, it may be time to rethink how you receive your nitrogen supply.

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Relying on liquid nitrogen and other supply methods such as gas cylinders, dewars, nitrogen tank rental & bulk liquid storage delivery create significant challenges for businesses as well as many additional and hidden costs, which ultimately impact on the bottom line compared to nitrogen gas generator which is the optimum solution of all nitrogen supply problems: lack of reliability, high cost and quality control on the product.

What are the Different Ways of Getting Oxygen or Nitrogen generation for Your Business?

Bottled nitrogen
liquid nitrogen
On-site gas generation

Let's get introduced on each method advantages & disadventages

Bottled nitrogen

Gas cylinders

A first option is to buy bottles of nitrogen from a nitrogen producer. This process is very straightforward: You order the desired nitrogen quantity for your application and the supplier delivers it to you in big heavy bottles. N₂O₂, generated by a cryogenic nitrogen plant, is converted into a gas and bottled under very high pressure (300 bar). This means a lot of nitrogen gas can be stored in a relatively small bottle. However, in order to withstand the high pressure, the walls of the receiver are very thick. These bottles are placed in a rack and get transported to their destination on trucks. After use, the emptied bottles are collected by the gas company.

Advantages:	Disadvantages:
If your nitrogen consumption is relatively low, it is a very easy solution. Since the nitrogen you have is readily available, peak flows are allowed. The installation is very simple.	Since the bottles are made of thick, heavy steel (and nitrogen is nearly weightless), the gas company is basically transporting iron, which is very environmentally unfriendly. The bottles can never be fully emptied. If the working pressure is 10 bar, you will only be able to get the nitrogen out when the pressure in the bottle is more than 10 bar. The ‘rest’ gas stays in the bottle and returns to the gas company when the ‘empty’ bottles are picked up. The price is comparatively high because of the effort the gas company has to put into getting the nitrogen to you. After generating the gas, they compress it, transport the heavy iron bottles to you and pick them back up when they are empty. A special bottle rack switching system is required if interruption of production process is not allowed. Safety concerns (heavy steel handling, high pressure) You are very dependable on your nitrogen supplier. Not suitable for high gas consumptions

Advantages:

Disadvantages:

If your nitrogen consumption is relatively low, it is a very easy solution.
Since the nitrogen you have is readily available, peak flows are allowed.
The installation is very simple.

Since the bottles are made of thick, heavy steel (and nitrogen is nearly weightless), the gas company is basically transporting iron, which is very environmentally unfriendly.
The bottles can never be fully emptied. If the working pressure is 10 bar, you will only be able to get the nitrogen out when the pressure in the bottle is more than 10 bar. The ‘rest’ gas stays in the bottle and returns to the gas company when the ‘empty’ bottles are picked up.
The price is comparatively high because of the effort the gas company has to put into getting the nitrogen to you. After generating the gas, they compress it, transport the heavy iron bottles to you and pick them back up when they are empty.
A special bottle rack switching system is required if interruption of production process is not allowed.
Safety concerns (heavy steel handling, high pressure)
You are very dependable on your nitrogen supplier.
Not suitable for high gas consumptions

Liquid Nitrogen

A second option is to install a liquid nitrogen storage tank on your site and get it filled up periodically by a gas company. These tanks can either be rent (from said gas company) or bought and an evaporator is required for you to be able to use the nitrogen in it. An evaporator transforms the liquid nitrogen into usable nitrogen in gaseous form. Just like nitrogen in bottles, it gets transported to your company by trucks. However, in this case, the nitrogen is transported in a big thermally insulated tank truck. The liquid nitrogen is then pumped from the truck into your insulated storage tank. It is also possible to order liquid nitrogen in smaller cans for smaller consumptions, these small tanks are known as dewars. Also, just like bottled nitrogen, liquid nitrogen is produced by a cryogenic nitrogen plant.

Advantages:	Disadvantages:
Since the nitrogen you have is readily available, peak flows are allowed. It is, in most cases, more cost effective compared to bottled nitrogen. Small capacity adjustments are relatively easy should your production and nitrogen requirements increase (if your evaporator can handle them without freezing)	Tank insulation is never perfect. This means the liquid gas will heat up, evaporate in the tank itself and pressure will rise until the safety valve opens and blows part of the gas off. These losses are called boil-off losses.* Long term contracts with the gas company are common practice (typically 5-7 years). Besides the tank you also need special foundation (which can withstand the extreme cold temperatures in case of a leak) and an evaporator. Not environmentally friendly. Safety concerns (liquid nitrogen is -196°C, there is a frostbite risk when working with liquid nitrogen) The evaporator can freeze up when your nitrogen consumption is higher than nominal or when it’s cold outside.

Advantages:

Disadvantages:

Since the nitrogen you have is readily available, peak flows are allowed.
It is, in most cases, more cost effective compared to bottled nitrogen.
Small capacity adjustments are relatively easy should your production and nitrogen requirements increase (if your evaporator can handle them without freezing)

Tank insulation is never perfect. This means the liquid gas will heat up, evaporate in the tank itself and pressure will rise until the safety valve opens and blows part of the gas off. These losses are called boil-off losses.*
Long term contracts with the gas company are common practice (typically 5-7 years).
Besides the tank you also need special foundation (which can withstand the extreme cold temperatures in case of a leak) and an evaporator.
Not environmentally friendly.
Safety concerns (liquid nitrogen is -196°C, there is a frostbite risk when working with liquid nitrogen)
The evaporator can freeze up when your nitrogen consumption is higher than nominal or when it’s cold outside.

Generating your own nitrogen

As opposed to the previous methods of getting nitrogen, generating your own does not involve the cryogenic process. Its extreme temperatures are nowhere to be found in membrane or Pressure Swing Adsorption (PSA) nitrogen generators. These generators have to separate the air into its components in a different way. PSA and membrane are two very different technologies, however they both need a stream of compressed air in order to work. Because these technologies are so different from cryo, the composition of the resulting gas will be different. Cryogenic nitrogen gas has a fixed, very high purity level. The nitrogen purity of commercially available generators can be adjusted to match your preferences, but gaining the same level of purity as cryo generated nitrogen is extremely inefficient. With these machines, higher purity levels require more power, resulting in higher running costs. That being said, for most applications the purity levels of cryogenic nitrogen are overkill. You can read more about nitrogen purity here.

Advantages:	Disadvantages:
In a lot of cases, generating your own nitrogen is the solution with the lowest total cost of ownership. Purity can be set according to your needs, the cost goes down together with N2O2 purity. You are independent from any gas suppliers. The gas price is very stable, you are only susceptible to changes in the price of the electricity to run your installation. It is a safe option (no low temperatures or high pressures). There is no waste (no returning of gas to the supplier, no boil-off losses), you produce what you need. Environmentally friendly compared to other options.	Special measures have to be taken to allow for peak flows (e.g. buffer tank, high pressure buffer tank, liquid gas buffer). A slight increase in gas consumption, above the nominal capacity of the installation, will have a bigger impact compared to liquid or bottled nitrogen. If the different components in the installation come from different suppliers, it might make communication & service more challenging.

Advantages:

Disadvantages:

In a lot of cases, generating your own nitrogen is the solution with the lowest total cost of ownership.
Purity can be set according to your needs, the cost goes down together with N2O2 purity.
You are independent from any gas suppliers.
The gas price is very stable, you are only susceptible to changes in the price of the electricity to run your installation.
It is a safe option (no low temperatures or high pressures).
There is no waste (no returning of gas to the supplier, no boil-off losses), you produce what you need.
Environmentally friendly compared to other options.

Special measures have to be taken to allow for peak flows (e.g. buffer tank, high pressure buffer tank, liquid gas buffer).
A slight increase in gas consumption, above the nominal capacity of the installation, will have a bigger impact compared to liquid or bottled nitrogen.
If the different components in the installation come from different suppliers, it might make communication & service more challenging.

What are the key benefits of on-site gas compared to delivered gas?

You save up to 80% on the cost of the nitrogen or oxygen compared to buying in nitrogen in bulk
Payback is usually under 18 months, and the product has a typical lifetime of over 10 years
A constant supply is ensured: you never have to worry about a delivery not getting to you in time again
Save space & minimize risk and handling errors: no need for gas bottles/liquid nitrogen tank in the yard
Simplify administration to save time & money with no weekly deliveries to manage
Very low running costs: uses your compressed air supply
high purity levels Up to 99.999% purity

How Do I Size a Nitrogen Generator System?

Knowing your annual spend on nitrogen, and whether your nitrogen usage spikes or fluctuates are key pieces of knowledge that will allow you to sizing a nitrogen generation system

It is important to know:

The required flow of nitrogen/oxygen
The required purity of nitrogen/oxygen
The input pressure of your compressed air supply
The pressure of the nitrogen/oxygen used in your application

Are nitrogen gas generator safe?

Yes! As the generator does not add or take anything away from the atmospheric air, you could have one running in a closed room with no change to the overall content of the atmosphere. They also negate the need to store and move potentially dangerous high pressure cylinders on site.

Will getting a quote mean lots of meetings with engineers, or searching for lots of facts & figures?

No, in order for us to size & price a system for you, we need 4 things:

The required flow of nitrogen/oxygen
The required purity of nitrogen/oxygen
The input pressure of your compressed air supply
The pressure of the nitrogen/oxygen used in your application

Why don't more companies have generators?

Traditionally, on-site gas generators were only economically viable in very large applications. With constant development, today's high efficiency products ensure that generators are economically viable for the smallest of applications, and an ever increasing number of companies are moving to generate their own nitrogen and oxygen.

Can Atlas Copco supply and install a complete on-site gas generation system with compressed air supply?

Yes, Atlas Copco Compressors can handle everything from air intake to pipework. Please check our typical installation for more information.

If you’re still having nitrogen cylinders delivered to your business — and especially if you’re a heavy nitrogen consumer who sees regular tank drop-offs/pickups at your facility — it may be time to consider all the P.R.I.C.E.-related benefits that on-site nitrogen generation can bring.

know more about gas generators?

Looking to get a quote for your nitrogen supply? Simply click on the button to provide you a budget quote and connect you with one of our nitrogen experts!

What are some practical applications of nitrogen gas?

With nitrogen being an inert gas, it is suited for a wide range of uses in many different industries. Take a look below at some of the typical industrial applications of nitrogen gas generator.

Oil and Gas