METHOD OF LIQUEFACTION OF METHANE, MAINLY FOR GAS-FILLING STATIONS OF TRANSPORT FACILITIES Russian patent published in 2002 - IPC

FIELD: cryogenic engineering; natural gas liquefaction stations, methane in particular for gas-filling stations. SUBSTANCE: proposed method is used for liquefaction of methane fed form low- pressure gas main; method includes compression of gas in high- pressure compressor followed by cooling in first and second methane counter-current heat exchangers and separation of methane into liquefied and gaseous phases at two stages; gaseous phase is returned to liquefaction cycle; after second methane counter-current heat exchanger and first stage of separation, methane is subjected to expansion; of liquid phase after first stage of separation is performed in restrictor; after first methane counter-current heat exchanger, methane is additionally cooled by Freon refrigerating cycle; after second methane counter-current heat exchanger methane is cooled in ejector at expansion to pressure of 5 atm from temperature not higher than 210 K to temperature not below 135 K or to pressure of 12 atm from temperature not higher than 210 K to temperature not below 154 K; after ejector, methane is subjected to first stage of separation into liquefied and gaseous phase; gaseous phase is returned to liquefaction cycle to inlet of high-pressure compressor through second and first methane counter-current heat exchangers; gaseous phase of methane is fed after second separation stage to intake chamber of ejector in the amount not exceeding 10% of total amount of methane delivered to ejector nozzle after second methane counter-current heat exchanger. EFFECT: enhanced operational and economical efficiency; low cost; enhanced operational reliability, safety and durability; improved labor conditions and safety precautions. 1 dwg