Cryogenic Nitrogen Plant

Specifications	Process
Applications

Cryogenic nitrogen plants are gas plants generating nitrogen using the cryogenic process. Cryogenic plants using cryogenic temperature are used for production of liquid and gaseous nitrogen from atmospheric air. While the cryogenic oxygen plants produce oxygen as the final product, nitrogen is also produced as a by product in the process. However, there are independent gas plants producing nitrogen alone. In other words, the cryogenic air separation units can produce both high purity nitrogen gas as a second product with oxygen and as a prime product in nitrogen generators, where gas is the final output. Being a relative inert gas, cryogenic nitrogen is used as a protective atmosphere to prevent oxidation.

Cryogenic nitrogen plants represent highly efficient equipment for large-scale nitrogen production with the nitrogen purity of up to 95-99% pure nitrogen. In most cases the cryogenic technology of nitrogen production proves economically feasible and are always considered more advantageous than membrane and adsorption systems.

Specifications of Cryogenic Nitrogen Plants
A typical cryogenic plant has two modules-a cold box and an warm end container. The cold box consists of a condenser, the rectification column and heat exchangers. The warm end container is usually equipped with an air pre-treatment unit, an air compressor, electrical devices and a control system.

Typical specifications for a cryogenic nitrogen plant that a buyer should know without additional purification and compression are:

• Capacity: Output capacity
• Purity: Nitrogen purity
• Pressure
• Ambient temperature during operation and storage

The Cryogenic Process and Technology
The cryogenic process separates air by using means of rectification. This makes use of the different evaporation temperatures of the air components. There are inlet filters in the pants which remove dust and other impurities from the air before it enters the air compressor. Here the air is compressed to the required process pressure. It is then pre-cooled. After moving through a moisture separator, the air enters one of two molecular adsorbers, where impurities are removed. Here, one adsorber is always effective while the other is being regenerated by residual gas from the separation process.

The processed air is then cooled at a liquefaction temperature in the main heat exchanger and then fed into the bottom of the rectification column. The pure nitrogen fraction is removed from the top column, then fed into the product line. Cold is supplied in the form of liquid nitrogen (LIN) from the back-up system. This is regenerated with an expansion turbine. The pure nitrogen is stored in cylinders or storage tanks and then distributed.

Flow diagram


Applications of Cryogenic Nitrogen Plants

• Chemical and petrochemical industry
  • Inerting/purging
  • Catalyst regeneration
• Blanketing
  • Metallurgy/Glass industry
  • Heat treatment
  • Refining
  • Purging
  • Inerting
• Electronic industry
  • Purging
  • Inerting
  • Packaging
  • Air Drying
• Food Industry
  • packaging
  • Inerting
• Oil and gas industry
  • Nitrogen fire fighting
  • Pipe-lines blowing
  • Air drying
  • Pressure testing
  • Technological tanks cleaning