METHOD OF LIQUEFYING NATURAL GAS USING REFRIGERATING CIRCUIT WITH CLOSED CYCLE Russian patent published in 2019 - IPC F25J1/02 

FIELD: technological processes.

SUBSTANCE: disclosed is a method of liquefying a stream of hydrocarbons from feed stream (1). Feed gas (1) is passed through heat exchanger (2) to provide at least partially liquefied hydrocarbon flow having temperature below -140 °C. Refrigerant flow (35) is extracted from heat exchanger (2) through outlet (33), where temperature in heat exchanger is highest. Coolant mixture is compressed with subsequent cooling. Coolant mixture (35) is added to phase separator (40) to produce gas flow of coolant (8) and x flows of liquid coolant (25), wherein x is integer from 1 to 10. Each of x flows of liquid coolant (25) is passed through heat exchanger (2) through different inlets for each fluid flow. Each of said liquid streams is discharged via outlet (28, 19) of heat exchanger (2) differing from others by temperature level. Flow of cooling gas (8) is passed through heat exchanger (2) from inlet (9) and to outlet (11) at temperature from -140 to -170°, to obtain liquefied stream (12), and then expanding obtained stream.

EFFECT: technical result is optimization of use of liquid and gas coolant flows in liquefaction cycle.

3 cl, 1 dwg