METHOD FOR PRODUCING LIQUEFIED NATURAL GAS AND INSTALLATION FOR ITS IMPLEMENTATION (OPTIONS) Russian patent published in 2022 - IPC F25J1/00 

FIELD: natural gas liquefaction technology.

SUBSTANCE: inventions group relates to natural gas liquefaction technology using an external refrigeration cycle. The high pressure natural gas stream is cooled, condensed and supercooled with a blended refrigerant stream, expanded and sent to a storage tank. The heated refrigerant return flow is compressed in the compressor stages with frequency control and cooled down after each stage. Before each compressor stage, a liquid phase is separated from the refrigerant stream in the first and second separators, which is pumped to mix with the compressed and cooled refrigerant stream in the third separator. After the second stage of the compressor, part of the refrigerant flow through the bypass line with a solenoid valve is fed into the gaseous refrigerant tank, from where it is fed through the control valve to the first separator. Before entering each four-stream heat exchanger, the refrigerant stream is separated into gas and liquid phases. A portion is withdrawn from the liquid phase, which is throttled and mixed with the return flow of the refrigerant. When the natural gas temperature changes before throttling, the compressor capacity is controlled by changing the shaft speed.

EFFECT: improving the energy efficiency of liquefied natural gas production.

10 cl, 2 dwg, 2 tbl