METHOD FOR LIQUEFITING NATURAL GAS "MODIFIED ARCTIC CASCADE" AND INSTALLATION FOR ITS IMPLEMENTATION Russian patent published in 2023 - IPC F25J1/00 

FIELD: gas transportation.

SUBSTANCE: liquefying natural gas for its further transportation by river and sea transport. Pre-processed natural gas is compressed by compressor 1, heat of compression is removed in air or water cooler 2, preliminarily cooled in multistage due to evaporation of heavy refrigerant in evaporators 3, supercooled due to cold recovery of light refrigerant vapor in shell-and-tube heat exchanger 7 and its preliminary evaporation in evaporator 8, the pressure of the liquefied gas is reduced by the pressure reducing means 10, the non-liquefied gas is separated, and the liquefied gas is discharged. The heavy refrigerant obtained by evaporation is compressed by compressor 4, condensed and reused in cooling natural gas. The light refrigerant is compressed by compressors 11, the heat of compression is removed on air or water coolers 12, then it is cooled successively by a light low-pressure refrigerant in a double-flow superheater 13 and an evaporating heavy refrigerant in an evaporator 3. The high-pressure light refrigerant is then separated into two streams. The isentropic expansion of the first stream is carried out by the expander 14. The second flow is sequentially cooled in the shell-and-tube heat exchanger 7, its isenthalpy expansion at the throttle 15 and evaporation in the evaporator 8 due to natural gas supercooling. The streams are then mixed at equal pressure and used as a single low-pressure light refrigerant stream.

EFFECT: invention provides deeper cooling of natural gas, as well as simpler hardware design of heat exchangers.

8 cl, 1 dwg