Method for liquefying a methane-rich feed gas, and corresponding facility

Abstract

The invention relates to a method for liquefying methane-rich feed gas (12), the method comprising:mixing the feed gas with recycled gas (18), compressing the gas to a pressure of between 19 and 70 bar absolute, and purifying the gas,a first pre-cooling of the gas to a temperature of between −40° C. and −15° C., and second pre-cooling of the gas by heat exchange with the recycled gas,liquefying the gas by heat exchange only with a liquefaction refrigeration cycle (46),sub-cooling the gas by heat exchange with at least the recycled gas, andexpanding the sub-cooled liquid (52) to obtain a liquefied gas (14) and the recycled gas representing a mole fraction of less than 35%.

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