METHOD AND DEVICE FOR PRODUCING STREAM OF LIQUEFIED NATURAL GAS Russian patent published in 2010 - IPC C10G5/06 C10L3/00 F25J1/02 F25J3/02 

FIELD: chemistry.

SUBSTANCE: invention relates to a method of producing a stream of liquefied natural gas in which before liquefaction of the natural gas, heavy hydrocarbon components with molecular weight higher than that of butane are removed, involving the following steps on which a mainly vaporous stream (1) of natural gas is formed with pressure and temperature of the stream of incoming gas; the stream of incoming gas (1) is fed into a distillation column (10) having two or more separation stages (11); the lower stream (17) is tapped from the lower part of the distillation column (10) and an upper stream (16) from the upper part of the distillation column (10), wherein the upper stream (16) contains relatively less components of heavy hydrocarbons than the lower stream (17); at least a portion of the upper stream (16) is liquefied to obtain a stream of liquefied natural gas; characterised by that before feeding the gas stream (1) into the distillation column (10), the stream of incoming gas (1) is divided into first and second sub-streams (3a, 3b) with a selected division ratio; the first sub-stream (3a) is fed into the distillation column (10) through a first inlet point (7a) in the lower part of the distillation column (10) at pressure which is not lower than pressure of the incoming gas stream (1) minus pressure fall from the said division of the incoming gas stream (1), wherein the first sub-stream (3a) is not heated starting from the point of division of the incoming gas stream (1) to the first inlet point (7a) of the first sub-stream (3a) into the distillation column (10); the second sub-stream (3b) is cooled in a heat exchanger (6) to temperature lower than temperature of the incoming gas stream; and the cooled second sub-stream (7) is fed into distillation column (10) at the second inlet point (7b) lying higher than the first inlet point (7a), wherein pressure is intentionally lowered in a pressure reduction device in the first and second sub-streams (3a, 3b). The invention also relates to a device for producing a stream of liquefied natural gas.

EFFECT: high efficiency of liquefying gas.

19 cl, 8 dwg