FIELD: gas industry.
SUBSTANCE: invention relates to natural gas liquefaction technologies, in particular to natural gas liquefaction technology using an external refrigeration cycle, and can be used at sites with access to natural gas. The high-pressure gas is supplied to the mercury purification unit, then it is dried and, after drying, the gas stream is supplied to the first heat exchanger for pre-cooling, in which it is cooled with a refrigerant in the form of propylene, or is directed through the bypass line for purification. The gas is then purified and sent to a second precooling heat exchanger. Then the gas is subcooled with a mixed refrigerant in a heat exchanger for cooling and in a heat exchanger for liquefaction, after which the resulting supercooled stream of high pressure liquefied natural gas is throttled to obtain liquefied natural gas of low pressure, which is passed through a low temperature separator. The resulting liquefied natural gas is sent for storage.
EFFECT: invention improves the quality of the obtained liquefied gas; increases the energy efficiency of the natural gas liquefaction plant, ensures the versatility and reducing the weight and size characteristics of the plant.
14 cl, 1 dwg, 2 tbl
