If you need high purity Nitrogen for your industrial process, then the chances are that you’re tied into a contract with one of the major suppliers of specialised gasses.
Although this arrangement can work, it does have its drawbacks. Not least, it’s generally inflexible, often costly and has the potential for disruption if your supplier has transport problems.
Even if supplies are on time, the entire issue of transportation over-complicates what can otherwise be a relatively simple process, as the gas has to be depressurised to allow it to be transported in a liquid state; once on-site it then has to be returned to a gaseous condition before it can be used.
There’s also the cost of maintaining on-site storage facilities, the uncertainty of price rises from your supplier and the cost associated with gas losses prior to reaching the point of use; these can often be in excess of 10% of the original volume supplied.
All in all, bulk supplies of Nitrogen combined with on-site storage do not always represent the best option if you require a flexible, cost-effective and on-demand solution.
On-demand & On-site
The alternative is to use an on-site method of gas generation, using a compact, self-contained system, which extracts Nitrogen cleanly and effectively from the surrounding atmosphere.
Nitrogen accounts for 78% of the air that we breath. By linking a standard air compressor with a specialised Nitrogen generator, it is possible to separate Nitrogen and Oxygen, producing a constant, or on-demand, flow of high purity gas; in the case of Nitrogen, this can be as high as 99.999%, which exceeds the level required by most industrial processes, from laser cutting to food packaging.
How it works
Although there are different techniques used in Nitrogen generation, perhaps the most reliable is Pressure Swing Adsorption (PSA). This involves passing filtered compressed air through a vessel containing a carbon molecular sieve (CMS). The CMS preferentially absorbs oxygen molecules from the air stream, allowing Nitrogen to pass to a reservoir from where it can be fed to a downstream production operation. The adsorption process continues until the activated carbon begins to become saturated with oxygen molecules, at which point the supply is switched to a second identical vessel, continuing uninterrupted while the first chamber automatically regenerates. Switching between vessels then continues automatically and, as there are no chemicals involved, can continue almost indefinitely.
PSA generator technology is proven, reliable, safe and low maintenance. It’s also modular, making it easy to scale the system to match the needs of each application.
Only as pure as you need
An important factor, regardless of the method of supply, is matching the level of Nitrogen purity correctly to the demands of the application. There is, for example, nothing to be gained by over-specifying the level of purity; instead, over-specification will simply add to your operating costs by using more energy or, if you’re sourcing gas externally, by increasing the price per unit.
Choose the right solution
On-site Nitrogen generation is not always the best option for everybody, especially if you have already invested in large storage silos, liquid Nitrogen dewars and associated distribution networks. In the large majority of applications, however, a compact and self-contained Nitrogen generator, capable of producing gas to the level of purity and in the volume your business requires, on demand, will provide a far more cost-effective and reliable option – one that eliminates distribution and storage problems, and the environmental issues associated with bulk gas road transport.
Learn more about specifying specialist gasses with this free guide.