Air Separation Units (ASU)

Centrifugal Compressors for Air Separation Units

Industry Requirements

While air may be free, the air separation process is not. Producing industrial gases requires a great deal of energy, making the need for an efficient compressed air system critical to plant success.

To produce industrial gases such as purified nitrogen or oxygen, atmospheric air is compressed, cooled, and separated in a distillation column or cold box. Once cryogenic separation is complete, the gases are used in other processes or compressed for storage and/or transportation.

The gases produced during this process can be used in a variety of areas including the production of chemicals and petrochemicals, liquefaction of natural gas (LNG), clean dry air for electronics manufacturing, production of synthetic liquid fuel from coal (CTL) or natural gas (GTL), integrated gasification combined cycle (IGCC) power plants or liquefaction of nitrogen for distribution. As a key component of the separation process, compressed air systems at air separation plants must be reliable and energy efficient to maintain low operating costs. 

Industry Solution

FS-Elliott’s comprehensive product portfolio and engineering capabilities provide competitive solutions for highly customized as well as standard projects.

The flexibility of FS-Elliott air compressors makes them ideal for serving various roles in an air separation plant including main air compressors (MAC), booster air compressors (BAC), nitrogen gas compressors (GAN), nitrogen recycle compressors (NRC), and clean compressed dry air compressors (CDA).

Additionally, FS-Elliott has the capability to provide multiple process combinations, such as MAC/BAC, MAC/BNC, and MAC/GAN. By offering superior operating life cycle costs, FS-Elliott compressors allow customers to quickly gain their return on investment. 

Explore compressed air solutions for air separation plants.

Air Separation Applications

Air Separation Products


  • P500+

    70 – 130 m3/min
    2,600 – 4,500 ICFM

  • P600+

    110 – 180 m3/min
    4,000 – 6,500 ICFM

  • P700+

    170 – 330 m3/min
    6,000 – 11,500 ICFM

  • PAP Plus BH

    90 – 160 m3/min
    3,500 – 5,700 ICFM

  • PAP Plus CH

    160 – 310 m3/min
    5,500 – 11,000 ICFM

  • PAP Plus D

    280 – 510 m3/min
    10,000 – 18,000 ICFM

  • PAP Plus EH

    440 – 700 m3/min
    15,000 – 24,500 ICFM

Case Study: Industrial Gas Producer Reduces Capital Expenditures


  1. Case Study

    Learn how an industrial gas producer reduced capital expenditures and increased overall efficiency.

    View full case study.

  2. Background

    An industrial gas producer opened a new air separation plant that required 4440 Nm3/h of air and 2100 Nm3/h of gaseous nitrogen for production.

    View full case study.

  3. Manufacturing Challenge

    Due to the modular design of the plant, the compressors selected for the project needed to be minimal in size but capable of high-efficiency gas production.

    View full case study.

  4. Results

    Customer reduced capital expenditures and increase overall efficiency by combining the air and nitrogen processes in one machine.

    View full case study.

Learn how an industrial gas producer reduced capital expenditures and increased overall efficiency.

View full case study.

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In my 30 years of industrial engineering, that is the finest piece of equipment that I have ever seen.
Corporate Facilities Engineer