METHOD FOR LIQUEFYING A HYDROCARBON-RICH FRACTION Russian patent published in 2021 - IPC F25J1/00 

FIELD: gas industry.

SUBSTANCE: invention relates to the gas industry and can be used in the liquefaction of gases. The liquefaction of the hydrocarbon-rich stream is carried out by means of a cascade of refrigerant mixture circuits consisting of three refrigerant mixture circuits. The compressed mixture of primary circuit refrigerants is condensed by ambient air and fed into a container. When it is not possible to achieve complete condensation (E4) of the compressed mixture (2) of refrigerants of the first circuit of the mixture of refrigerants, the gas phase (6) of the partially condensed mixture of refrigerants collected in the container (D1) is compressed (С1'), at least partially condensed (E8) by ambient air, expanded (V5) and sent back (7) to the container (D1). The gas phase (6) is compressed to a pressure corresponding to at least 1.5, preferably from 2 to 2.5, of the pressure in the container (D1). A mixture of primary circuit refrigerants consists of at least two components from N₂, CH₄, С₂Н₄, С₂Н₆, С₃Н₆, С₃Н₈, iso-С₄Н₁₀, н-C₄H₁₀, while the maximum proportion of components N₂ and СН₄ is 1 mol%.

EFFECT: reduced energy costs and reduced loss of LNG productivity during the "summer period".

3 cl, 1 dwg