METHOD FOR LIQUEFYING A NATURAL GAS STREAM CONTAINING NITROGEN Russian patent published in 2023 - IPC F25J1/00 

FIELD: gas industry.

SUBSTANCE: method for liquefying a natural gas feed stream, comprising the steps of: step a): cooling the gas feed stream to obtain a liquefied natural gas stream at a temperature T1 and a pressure P1b; step b): introducing the stream obtained in step a) into a denitration column at a pressure P2 and at a temperature T2 which is lower than T1, in order to obtain a denitrated liquefied natural gas stream at the bottom and a nitrogen-enriched vapour stream at the top; step c): condensing the nitrogen-enriched vapour stream obtained in step b) in a heat exchanger to obtain a two-phase stream; step d) introducing the two-phase stream obtained in step c) into the phase separation vessel in order to obtain a liquid stream and a gas stream enriched in nitrogen. At least a portion of the liquid stream obtained in step b) is used during step c) to cool the vapour stream obtained in step b) in said heat exchanger.

EFFECT: cost reduction.

11 cl, 1 dwg