METHOD OF PRODUCING LIQUEFIED METHANE OF HIGH PURITY Russian patent published in 2025 - IPC F25J3/02 

FIELD: cryogenic equipment.

SUBSTANCE: invention relates to cryogenic engineering and can be used in gas industry to produce liquefied methane of high purity. Method of producing high-purity liquefied methane includes pre-cooling in a first heat exchanger, cooling in a second heat exchanger to form a two-phase flow, which is removed from the second heat exchanger and separated in the first separator into steam and liquid. Liquid after the first separator is throttled in the first throttle and directed to the second separator, where it is separated into liquid and steam, after which the liquid is sent to the first heat exchanger for cold recovery and then for recycling, and steam from the second separator is throttled in the second throttle and is directed to the lower part of the first rectification column. Steam from the first separator is returned to the second heat exchanger for further cooling and liquefaction, the obtained liquid is throttled in the third throttle and sent to the upper part of the first rectification column, in which separation is carried out to obtain a liquid, which is removed from the lower part of the first fractionation column and sent as a return flow to a second heat exchanger for cold recovery, after evaporation and heating, the obtained gas is sent to a circulation compressor of natural gas, then it is mixed with natural gas supplied to the first heat exchanger, and steam enriched with methane and nitrogen, which is removed from the upper part of the first rectification column and is directed after throttling in the fourth throttle for further separation into the second rectification column, to obtain liquefied methane of high purity, which is removed from the lower part of the second rectification column and is directed after throttling in the fifth throttle into a storage system, and steam enriched with nitrogen, which is removed from the upper part of the second rectification column and sent for recycling. Cooling and liquefaction of natural gas in the second heat exchanger is carried out by means of an external closed nitrogen circulation circuit.

EFFECT: obtaining liquefied methane of high purity.

1 cl, 1 dwg, 1 tbl