Technological process of LNG Plant
Here we’d like to introduce the general technological process of LNG Plant. However, if the gas source condition, inlet pressure and inlet temperature are different, the process differs a little bit.
The equipment scale and composition
Natural gas processing scale is 6MMSCFD, so it is 16×104Nm3/d (standard condition: 0℃,1atm) . So, the natural gas treatment capacity is 16×104Nm3/d.
Annual operation time: 8000 hours
Equipment combination list
Filtration boost system, deacidification gas system, and dehydration and demercuration system. Liquefaction system and storage and transportation system and venting system. Public utility system and fuel gas motor system and pipe rack. Fire control system and power distribution control room.
Deacidification gas system includes these main facilities: Adsorption tower, deacidification gas-liquid separation tank, filtration separator, deacidification gas cooler, rich amine flash tank, barren-rich amine heat exchanger, barren amine feeding pump, desorber, tower bottom reboiler and tower top liquid condensation pump, liquid condensation tank, tower top cooler, active carbon filtration and barren amine filter, etc.
Moreover, dehydration and demercuration system include these main facilities: Molecular sieve tower, regeneration gas separator and regeneration gas cooler, demercuration tank, demercuration tank outlet dust filter and regeneration gas heating furnace.
Further, liquefaction system includes these main facilities: Refrigerant compressor inlet separator and refrigerant compressor, refrigerant compressor inter-grade cooler and refrigerant compressor outlet cooler, cold box, propane drying bed, isopentane drying bed, refrigerant recuperator, propane storage tank, isopentane storage tank, refrigerant storage tank, heavy hydrocarbon separator and ethylene storage tank, etc.
The technological proposal of this equipment is as below: feed gas (31℃, 0.7MPa) will be boosted to 3.8MPa after filtration, and then goes to natural gas cleaning device (deacidification gas unit and dehydration & demercuration unit), in order to remove CO2, water and mercury in the natural gas. Afterwards, the cleaned natural gas enters liquefaction device (cold box), so it will cool to cryogenic LNG. The cooling system adopts the mixed refrigerant cooling technology.
Moreover, the technological process is as below: