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PSA Nitrogen Plant
- Fully Automatic Operation requiring no special attention
- Generates Nitrogen as and when required
- Easy to install and maintain
- Purity of Nitrogen upto 99.9999% can be achieved
- Generates Nitrogen at almost 1/10 th cost of cylinder nitrogen
- Proven Technology
- More than 1000 Plants based on PSA Technology operating successfully in India.
The compressed air is passed through a Twin Tower PSA module interconnected with automatic changeover valves. At the bottom of PSA towers, Activated Alumina is provided which has tendency of adsorbing moisture from compressed air. After passing through this bed of Activated Alumina air gets dried. Supply of dry compressed air from this layer of desiccant (activated alumina) will be continuous without any interruption. Dried compressed air will now come in contact with bed of carbon molecular sieves (CMS). Carbon Molecular Sieves are special grade of absorbent which have the property of preferential adsorption of oxygen molecules. At a time one tower remains under nitrogen production cycle, whereas the other tower undergoes regeneration which is achieved through de-pressurization of the tower to atmospheric pressure. The two towers of PSA modules are inter-connected with automatic changeover valves through pneumatic signal given by solenoid valve which in turn get the electrical signal from the timer provided in the control panel. The changeover time cycle will be 1 + 1 minute. The outgoing nitrogen gas is sent to a surge vessel where the minimum nitrogen pressure will be maintained with the help of Back pressure Regulator. The product nitrogen will now be sent to the consumer point through a pressure reducing valves at required pressure.
Downstream equipments for High Purity
Oxygen content in product nitrogen can be brought down to 1-3 PPM with the use of DEOXO Unit.
Palladium De-Oxo Unit:
In this unit the residual oxygen in Nitrogen From PSA Unit is mixed with Hydrogen and the mixture is passed over Palladium Catalyst where Hydrogen reacts with Oxygen and makes water. The reaction is exothermic and the outlet gas is cooled down in After-Cooler where moisture vapor condenses and it is separated and drained out in moisture separator.
This nitrogen still contains moisture in vapor form which is removed in Gas Dryer and the outlet Nitrogen is at (-) 60 Deg C Dew Point (Atm).
The final product Nitrogen composition is
- Oxygen: 3 ppm
- Hydrogen: 0.2% (Adjustable)
- Dew Point: (-) 60 Deg C
- Nitrogen: Balance
Copper De-Oxo Unit
Alternately where hydrogen in product nitrogen is not acceptable, Copper De-Oxo units are used. In this system, one tower remains in the Oxygen removal cycle, whereas, the other tower undergoes regeneration of the catalyst. Oxygen removal is obtained by reaction of Oxygen present in Nitrogen with Copper Catalyst as per following equation.
- Oxygen: 1 ppm (Max.)
- Hydrogen: Nil
- Nitrogen: Balance
- Dew Point: (-)600C.
- Gas pressure: 5.0 Kg/cm 2g
- Gas temperature: Ambient
Salient Features
- The PSA type gas generator is fully automatic and the gas of proper specification is made available within short period after start-up.
- This type of gas generator does not require any fuel.
- Since the feed stock for this gas generator is air, there is no problem like soot formation or presence of Co2 etc. The common problem in fuel combustion based gas generator.
- The gas generator is very compact requiring very small floor area.
- Depending on the pressure in the nitrogen storage tank, the gas generator keeps running with ON/OFF operation like compressed air installation. Therefore, the gas generator would work only to the extent of meeting your gas requirement as and when needed.
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