Major steps of liquefied natural gas (LNG) production process

liquefied natural gas production process: A liquefied natural gas (LNG) plant mainly divided into five processes, the are-

  1. Pre-treatment
  2. Acid gas removal,
  3. Dehydration,
  4. Liquefaction
  5. Heavy oil separation.
LNG process flow diagram

LNG process flow diagram

Pre-treatment: This is mainly a unwanted substance removal step, In this process, all undesired particles are removed from the  natural gas, which is  taken from a gas field. Then a slug catcher is used to separate all remaining oil and water.

Acid gas removal: Some environmental pollutant such as, carbon dioxide (CO2 ) and hydrogen sulfide (H2S) present in natural gas taken from gas field must need to remove. An amine absorber or acid gas remover (AGR) is used to remove these impurities from natural gas by absorption process. And sulfur is also extracted and removed from hydrogen sulfide (H2S) using a sulfur removal unit (SRU).

Dehydration: All water dissolve with natural gas need to remove, because during liquefaction process these water particle can result ice formation. An absorbent is used for removing water from natural gas. Before liquefaction traces of harmful mercury also need to be removed.

Liquefaction and Heavy oil separation: This is the most important step of an LNG plant, the core process of an LNG plant is heavy compounds separation which is done by cooling and liquefying natural gas to –160°C or less using refrigeration principal. During this process gas is cooled and liquefied to an extremely-low temperature, huge amount of energy is consumed. The important factor is, the amount of energy can be reduced, so various inventive processes have been suggested and commercialized.

liquefaction processes: Major liquefaction processes are-

  • C3-MR method
  • AP-X method
  • Cascade method
  • DMR method
  • SMR method

An enormous refrigeration compressor required for all these methods. High capacity Gas turbines are used to drive them, So high-level engineering knowledge and experience is required to design, manufacture and assemble the compressors including gas turbines.


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