METHOD TO LIQUEFY NATURAL GAS BY COOLING MIXTURES, CONTAINING AT LEAST ONE NON-SATURATED HYDROCARBON Russian patent published in 2015 - IPC F25J1/02 

FIELD: power engineering.

SUBSTANCE: invention relates to the method of liquefaction of natural gas in a plant comprising two cooling circuits, where natural gas is cooled by means of heat exchange with the first cooling mixture, in the first cooling circuit. For this purpose they compress the first cooling mix MR1; the compressed first cooling mix is condensed; natural gas and compressed and condensed first cooling mix are supercooled by means of heat exchange with the first expanded fraction; the supercooled first cooling mix is divided into the first and second fractions, the first fraction is expanded to the first pressure level; natural gas and second fraction are cooled by means of heat exchange with the second fraction, expanded to the second pressure level. Then the specified natural gas is liquefied by means of heat exchange with the second cooling mix, in the second cooling circuit. For this purpose they compress the specified second cooling mix MR2; the second compressed cooling mix is condensed; the compressed and condensed second mix is cooled by means of heat exchange with the first fraction and the second fraction; the second cooling mix is expanded to the third pressure level; natural gas is cooled with the expanded second cooling mix to produce liquefied natural gas. In the method the first and second cooling mixes contain one saturated hydrocarbon and ethylene.

EFFECT: invention makes it possible to simplify a plant, and also to produce best thermal efficiency of the method.

6 cl, 5 dwg