Know About Nitrogen PSA Plant Working Principle

Nitrogen PSA Plant

Nitrogen(N2) is one of the most abundant gases comprising as it does 78% of the atmosphere the remaining is occupied by 21% of Earth’s atmosphere. N2 is extracted in high concentrations for use in industries such as chemical, steel, coal mines, bulk drugs, pharmaceuticals, food and electronics. N2 plant working principle is based on the PSA (pressure swing adsorption) technology. Nitrogen generators are able to generate high purity N2 gas with the PSA process. It is a quality and trusted process for separating nitrogen from compressed air by adsorption oxygen in the compact tower of carbon molecular sieves.

After being compressed the air enters an adsorption tower where it is passed through a carbon molecular sieve. During the passage oxygen is preferentially is adsorbed while nitrogen is allowed to pass through the sieve and is collected as a product gas. When the oxygen adsorbing capacity of a bed is used up the feed changes over to the new adsorption tower with the old being regenerated through quick depressurization and is ready for the next cycle.

Nitrogen Technical specifications –

  • Nitrogen purity: 95-99.99%
  • Dew Point: (-) 40 °C to (-) 60 °C
    N2 capacity: 05 to 1000 Nm3/hr
  • Pressure: 5-35 bar

Types of nitrogen plant working principles

There are four processes that are widely used in the industrial production of nitrogen which are pressure swing adsorption (PSA), cryogenic distillation, vacuum pressure swing adsorption (VPSA) and membrane separation.  All of them are widely used in the commercial production of nitrogen which finds application in various industries ranging from steel, metallurgy, pharmaceuticals, food packaging, chemicals and refining and petroleum.  

The businesses can choose anyone of these nitrogen production principles depending upon their nitrogen generation requirements. Industries that are small scale in size tend to use either PSA plant, VPSA plant or membrane plant for onsite nitrogen generation. These methods can generate nitrogen with purity up to 99.5% and are easy on the budget. Cryogenic distillation nitrogen working principle allows you to generate nitrogen with purity up to 99.99% which meets the requirements of all types of nitrogen industrial applications. This method is suitable for large scale production and is mostly used in medium to large scale businesses. All of these methods would provide you with access to the uninterrupted supply of nitrogen around the clock. India B2B Platform

How does N2 PSA plant working principle work?

PSA nitrogen system comprises of four main processes – Air compression, air pretreatment, adsorption/desorption and product delivery. Nitrogen generator working on PSA process is made up of twin adsorbing towers filled with carbon molecular sieve (CMS). As pre-filtered and compressed air is moved through the one adsorber, oxygen is adsorbed in the CMS and nitrogen is collected as a product gas. And the waste gas, in this case, oxygen is directed back into the atmosphere. When adsorption is taking place in one tower the other tower gets regenerated through depressurization to atmospheric pressure. This PSA N2 plant working principle ensures that you continue to get uninterrupted supply of nitrogen.

Nitrogen generation with VPSA working principle

VPSA nitrogen plants use the well-established technology of Zeolite Molecular Sieves (ZMS) & Vacuum system for regeneration. In the VPSA process, nitrogen molecules with diameter larger than oxygen get stuck in the pores of ZMS and are adsorbed. Subsequently, nitrogen is collected as a product gas.  Since adsorption of nitrogen occurs at a low temperature making the gas ideal for higher flow rates. In this process the regeneration process is accomplished with vacuum pumps with total regeneration of ZMS.  

However, the process of adsorption technology is cyclical in nature where ZMS is provided with alternately with pressurized air to generate the required product gas and regenerated by vacuum to eliminate the waste gases from the sieves.

Cryogenic distillation principle for nitrogen production

Cryogenic distillation is one of the most used processes for commercial production of nitrogen. It achieves the separation of air into constituent gases such as nitrogen, oxygen, etc, on the basis of different boiling of the gases.  The process starts with the intake of the ambient air into the air separation unit (ASU). Afterwards, the air is filtered and compressed and is passed into a purification unit where impurities like moisture, hydrocarbons and carbon dioxide are removed.

After being purified, the air is passed through a series of heat exchangers where it is cooled to cryogenic temperatures. Having achieved liquefaction of the air, it is moved into a high pressure distillation column where it is separated into constituent gases oxygen and nitrogen. The chosen gas, nitrogen in our case, is now taken into a low pressure distillation column where it is distilled to generate nitrogen with the specified purity.

Membrane separation process for nitrogen production

Many industries also use the principle of membrane separation for nitrogen generation. The process makes use of a membrane made up of permeable hollow fibers, which help in the separation of nitrogen from the atmospheric air through the selective permeation.  The membrane walls get permeated with the “fast” gases (oxygen, carbon dioxide, moisture) a lot quicker than “slow” gases (nitrogen).

Subsequently, the membrane achieves the separation of air through two streams, the permeate and the product. The permeate is made up of CO2, O2 and water vapor which are evaporated back into the atmosphere. The product is collected at the downstream end of the membrane. However, there is an option for using supplemental booster for getting more compression.

Applications of PSA N2 plant working principle

It is applied in numerous industries for generating nitrogen with high purity. Use of PSA N2 plant working principle is handy in the fabrication of the plants as PSA is simple, affordable and efficient technology. Important industrial applications are given below:

  • Blanketing (Pharmaceuticals, Pesticides, Agriculture)
  • Metal Process (Bright Annealing, Pleat Treatment, Furnace)
  • Inertization Process (Chemicals, Petrochemical)
  • Oil & Gas (Blanketing, Filling, Transferring)
  • Food Packet (Pouch Packaging, Confectionaries)
  • Laboratories (LCMS, GC)
  • Tyre Filling (Automobiles)
  • Power Sector
  • Electronics Industries
  • Autoclaves Segments
  • Cement Industry

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