On-site Nitrogen Systems: Comparing Your Options
Large volumes of gaseous nitrogen are required in various industrial processes today. Consequently, sourcing sufficient quantities of gas is a key challenge faced by process managers/operators. Nitrogen can either be generated on-site or supplied to an industrial site from an external source. This article will discuss the various options available to operators that utilize nitrogen in their processes.
Nitrogen System Types
There are three main nitrogen generation system types available for the production of large quantities of gas.
- Pressure Swing Adsorption
- Membrane Nitrogen Generators
- Fractional Distillation
PSA Nitrogen Generation Systems
This nitrogen system type operates using the principle of differential separation of gases flowing through an adsorptive material to achieve nitrogen gas generation. When a gaseous mixture (usually air) is passed through a specialized adsorptive material, the individual gases will be separated based on their molecular characteristics.
The pressure swing adsorption (PSA) technique is a two-stage adsorption and desorption process.
This is the first stage in the PSA nitrogen generation process. It involves using carbon molecular sieve material housed in two adsorptive towers to selectively retain oxygen in an air mix while allowing nitrogen to pass through to a collecting unit.
The desorption process is essentially a reversal of the adsorption process, allowing regeneration of the molecular sieve material for a further round of separation. Oxygen captured by the sieve is released to desaturate in preparation for a new cycle of gas filtration.
As earlier stated, the PSA system incorporates two adsorptive towers. These units alternate between adsorption and desorption, with the entire process taking an average of sixty seconds.
Membrane Nitrogen Generators
This technology is based on the selective permeabilities of different gases when applied across a semi-permeable membrane. Various gases possess distinct physical properties that affect their travel speed and their rate of absorption through a semi-permeable medium. The membranes used in nitrogen generation are made up of hollow fibers that increase their surface area, allowing faster absorption rates.
The critical components of a membrane nitrogen generator are listed below:
- Feed filter coalescers
- Activated carbon filters
- Particulate filters
- Immersion heaters
This nitrogen generation system produces a very high purity gas (99.999%) using a gas plant that distills air. To begin with, the air is first supercooled to its liquefaction point, and then its component gases are distilled out in order of their boiling points.
Nitrogen System Alternatives
In addition to the on-site methods of generating nitrogen gas mentioned earlier in this article, manufacturing processes utilizing nitrogen gas can be supplied with required volumes via external supply routes. Three common nitrogen system alternatives are the use of gas cylinders, nitrogen dewars, and bulk tanks.
Nitrogen gas for industrial use is often required in a pressurized form. Nitrogen gas cylinders supplied by an external vendor are a viable but costly alternative to on-site gas generation. Apart from the recurrent costs of procuring nitrogen gas cylinders, there are other drawbacks to the method, including:
- Safety hazards resulting from the transport, storage, and handling of highly pressurized gas cylinders. Various mechanical injuries can result at any point in gas cylinder use.
- Gas wastages are common as it is impossible to empty a gas cylinder. There is always a certain residual amount of gas in the “empty” cylinder despite plant operators paying for its entire contents.
- Lastly, supply chain disruptions affecting cylinder delivery can cause costly process downtimes.
Dewars are large stainless-steel tanks that can be used in delivering bulk quantities of gaseous nitrogen to an industrial site. Although they can be used to deliver large volumes of gas quickly, they possess similar drawbacks with gas cylinder use. Additionally, off-gassing, where liquid nitrogen is converted to gas and dissipated discourages gas storage in dewars.
Nitrogen Bulk Tanks
Nitrogen bulk tanks can be installed on-site to provide a constant gas supply; however, they come at a cost. As the name implies, they are bulky structures that will consume valuable industrial floor space. Additionally, off-gassing is as much of a challenge as with the use of dewars. Rental, installation, and maintenance costs might make them unsuitable for some applications.
Benefits of On-site Nitrogen Systems from NiGen
After carefully considering the nitrogen generation methods available for industrial use, on-site generation stands out as the most cost-effective strategy.
NiGen offers the very best on-site generation services for your nitrogen needs. The key benefits of utilizing nitrogen systems from NiGen are outlined below.
Using NiGen nitrogen generators allows operators to eliminate recurrent costs on hiring nitrogen gas cylinders. NiGen generators also save on potential wastages as only the required quantities of the gas are generated and utilized at any given point. Finally, we offer cost-effective rental services guaranteed to optimize your nitrogen generation process.
Savings on Time
Utilizing our nitrogen generators eliminates the risk of downtime from interruptions in the supply of nitrogen that occurs using cylinders, dewars, or bulk tanks.
Reliability and Safety
NiGen offers safe and reliable nitrogen generator rentals in various industrial processes. The occupational health hazards posed by storage and handling of pressurized nitrogen are virtually non-existent as required quantities of the gas are generated and utilized immediately.
Ease of Installation
The modular design of NiGen’s membrane nitrogen generators makes them very easy to install. In addition, dedicated technicians are available to provide support during installation and equipment maintenance.