METHOD AND DEVICE FOR LIQUEFYING NATURAL GAS UNDER HIGH PRESSURE Russian patent published in 2007 - IPC F25J3/00 F25J1/02 

FIELD: apparatus for liquefying gas.

SUBSTANCE: method comprises cooling natural gas in the heat exchanger with the use of a mixed coolant and supplying the flow to the zone where the liquid is separated to produce the first gas flow and first liquid flow. The first liquid flow is supplied to the tower for separating methane at a temperature of lower than -40°C and under a pressure of lower than 4.48 MPa to produce the second gas flow containing methane and the second liquid flow containing the liquid components of the natural gas. The first gas flow is supplied to the turbo-expander to reduce pressure in the first gas flow down to a value of lower than 4.48 MPa and producing the gas flow of reduced pressure. The reduced pressure gas flow is supplied to the apparatus for separating methane. The second gas flow is supplied to the compressor that is actuated by the turbo-expander and is compressed up to a pressure no less than 3.45 MPa to produce the flow of compressed gas. The flow of compressed gas is supplied to the heat exchanger for concentration under a pressure of no less than 3.45 MPa for producing liquefied natural gas.

EFFECT: enhanced efficiency.

15 cl, 4 dwg