Nitrogen: What is it and where is it used?
21 April, 2022
Nitrogen is all around us. It is the biggest component of the air we breathe, but we don't use it. In this article we take a look at some of the many things it can be used for.
Generating Nitrogen with Pressure Swing Adsorption (PSA) Technology
Gas generation Membrane nitrogen generator Technologies Compressed Air Wiki Nitrogen Pressure swing adsorption PSA nitrogen Basic Theory
Having the ability to create your own nitrogen means being in full control of your N2 supply. This could be beneficial to a lot of companies that need nitrogen on a daily basis. What does that mean for your company? When nitrogen is generated in-house, you do not have to rely on third parties for the supply, therefore eliminating the need for processing, refills and delivery costs. One way of generating nitrogen is through Pressure Swing Adsorption.
How does Pressure Swing Adsorption work?
This flow is required to push out the oxygen that was captured in the previous adsorption phase of tower B. By releasing the pressure in tower B, the carbon molecular sieves lose their ability to hold the oxygen molecules. They will detach from the sieves and get carried away through the exhaust by the small nitrogen flow coming from tower A. By doing that the system makes room for new oxygen molecules to attach to the sieves in a next adsorption phase. We call this process of ‘cleaning’ an oxygen saturated tower regeneration.
What is Pressure Swing Adsorption Gas Generation
PSA stands for pressure swing adsorption. It is a technology that can be used to generate nitrogen or oxygen for professional purposes.
First, tank A is in the adsorption phase while tank B regenerates. In the second stage both vessels equalize pressure to prepare for the switch. After the switch, tank A starts regenerating while tank B generates nitrogen.
At this point, the pressure in both towers will equalize and they will change phases from adsorbing to regenerating and vice versa. The CMS in tower A will get saturated, while tower B, due to the depressurization, will be able to restart the adsorption process. This process is also referred to as ‘swing of pressure’ , which means that it allows for certain gases to be captured at higher pressure and released at lower pressure. The two tower PSA system allows for continuous nitrogen production at a desired purity level.
Nitrogen purity and requirements for the intake air
A typical installation: Air compressor, dryer, filters, air receiver, nitrogen generator, nitrogen receiver. The nitrogen can be consumed directly from the generator or through an additional buffer tank (not shown).
Another important aspect in PSA nitrogen generation is the air factor. It is one of the most important parameters in a nitrogen generator system, as it defines the compressed air required to obtain a certain nitrogen flow. The air factor thus indicates a generator’s efficiency, meaning a lower air factor indicates a higher efficiency and of course lower overall running costs.
Choosing between a PSA and Membrane generator
|
PSA |
MEMBRANE |
ACHIEVABLE PURITY |
EFFICIENTLY UP TO 99.999% |
EFFICIENTLY UP TO 99.9% |
EFFICIENCY |
HIGHER |
HIGH |
PERFORMANCE VS. TEMP. |
LOWER AT HIGH TEMP. |
HIGHER AT HIGH TEMP. |
SYSTEM COMPLEXITY |
MEDIUM |
LOW |
SERVICE INTENSITY |
LOW |
VERY LOW |
PRESSURE STABILITY |
FLUCTUATING IN/OUTLET |
STABLE |
FLOW STABILITY |
FLUCTUATING IN/OUTLET |
STABLE |
START-UP SPEED |
MINUTES/HOURS |
SECONDS |
WATER (VAPOUR) SENSITIVITY |
PDP MAX 8°C |
NO LIQUID WATER |
OIL SENSITIVITY |
NOT ALLOWED (< 0,01mg/m³) |
NOT ALLOWED (< 0,01mg/m³) |
NOISE LEVEL |
HIGH (blow-off peaks) |
VERY LOW |
WEIGHT |
MEDIUM |
LOW |
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Generating Nitrogen using Membrane Technology
21 April, 2022
Nitrogen can be generated on site with membrane generators. These machines are based on a very simple working principle. Learn more.