METHOD FOR LIQUEFYING NATURAL GAS Russian patent published in 2023 - IPC F25J1/02 

FIELD: production of liquefied natural gas.

SUBSTANCE: method of natural gas liquefaction is intended for the production of liquefied natural gas (hereinafter referred to as LNG), which ensures the regulation of the productivity of the produced LNG under conditions of fluctuations in the climatic parameters of the environment, and can be used at gas processing plants located in different regions of the country or the world, regardless of the climatic zone. The method of liquefaction of natural gas provides for the process of liquefaction of natural gas in different climatic zones and includes a stage of pre-cooling to the minimum average monthly temperature of the climatic zone of the streams cooled due to the external environment of the prepared external natural gas and refrigerants used after compression due to the supply of cold streams from an external and/or internal source to the aftercoolers, while streams of cooled natural gas and/or inert gas and/or individual hydrocarbons circulating in a separate refrigeration circuit are used as cold streams from an external source, while as streams cold from an internal source, a part of the flow of prepared natural gas supplied for liquefaction (hereinafter referred to as stream A) is used, which is subjected to additional compression and cooling using cold the environment, subsequent cooling and supply of part of the flow of compressed cooled natural gas (the first part of the flow A) for mixing with natural gas supplied for liquefaction, and part of the compressed flow of cooled natural gas (the second part of the flow A) after expansion to cool the refrigerants used and natural gas supplied for mixing, while (a) in single-circuit liquefaction schemes using a mixed refrigerant, (b) in double-circuit liquefaction schemes using several consecutive single-section heat exchangers, (c) in double-circuit schemes liquefaction with the use of a multi-section heat exchanger for cooling and liquefaction of natural gas prepared for liquefaction with a mixed refrigerant, after cooling of the prepared natural gas and the corresponding refrigerants is provided by aftercoolers. The claimed invention provides an increase in the annual production of LNG and a decrease in the level of climate dependence of the production method, taking into account climatic changes in the ambient temperature during the operation of an LNG production enterprise due to the after cooling of natural gas flows and refrigerants after they are compressed in the aftercoolers of cold flows from an external and internal source.

EFFECT: increase in the annual production of LNG and decrease in the level of climate dependence of the production method, taking into account climatic changes in ambient temperature during the operation of an LNG production facility.

4 cl, 5 dwg, 3 tbl