C2+ Recovery for LNG

Process

C2+ recovery allows meeting the heating value requirements for the natural gas to pipeline. The ethane and heavier hydrocarbons recovered become valuable feeds for crackers producing olefins and subsequentially for polyethylene and polypropylene plants.

The recovered hydrocarbons are: ethane, propane, butane and C5+ in four successive distillation columns.

 

Advantages:

  • Sofregaz proposed C2+ recovery from LNG uses the cold recovery integration – it uses the sub-cooled LNG as refrigerant for reliquefaction of the recovered methane at demethanizer overhead and supply reflux duty for the column. Recovered reliquiefied methane within specification is pumped at pipeline pressure eliminating the need of a compressor.
  • The design of two cryogenic heat exchangers integrated in one cold box. Rich LNG is heated in cryogenic heat exchangers before entering the flash drum and the demethanizer. Overall, lean LNG condensation (reliquefaction) coming from demethanizer overhead, duty is supplied be heating of the sub-cooled LNG using rich LNG as refrigerant.
  • The process is used to recover approximately 90% of the ethane from LNG.

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