SYSTEM AND METHOD FOR LIQUEFACTION WITH A COMBINED COOLING AGENT Russian patent published in 2021 - IPC C10G5/06 F25J1/00 F25J1/02 

FIELD: heat exchangers.

SUBSTANCE: invention relates to a method for cooling a hydrocarbon feed stream by means of indirect heat exchange with a stream of a first cooling agent in a cooling heat exchanger, including: a) compressing a warm stream of a first low pressure cooling agent in one or more compression stages to produce a compressed stream of the first cooling agent; b) cooling the compressed stream of the cooling agent in one or more cooling units to produce a compressed cooled stream of the first cooling agent; c) introducing the compressed cooled stream of the first cooling agent into the first liquid-vapour separating apparatus to produce a first stream of the cooling agent vapour and a first stream of liquid cooling agent; d) introducing the first stream of the liquid cooling agent into the cooling heat exchanger; e) cooling the first stream of the liquid cooling agent in the cooling heat exchanger to produce a cooled stream of the liquid cooling agent; e) throttling the cooled stream of the liquid cooling agent to produce a cold stream of the cooling agent, introducing the cold stream of the cooling agent into the cooling heat exchanger to provide cooling supply required to cool the hydrocarbon feed stream, the first stream of the liquid cooling agent and the stream of the second cooling agent; g) compressing the first stream of the cooling agent vapour in one or more stages of compression to produce a compressed stream of the cooling agent vapour; h) cooling and condensing the compressed stream of the cooling agent vapour to produce a condensed stream of the cooling agent; i) throttling the condensed stream of the cooling agent to produce a throttled stream of the cooling agent; j) introducing the second stream of the cooling agent into the cooling heat exchanger; k) introducing the hydrocarbon feed stream into the cooling heat exchanger; and l) cooling the hydrocarbon feed stream in the cooling heat exchanger to produce a cooled hydrocarbon stream; and m) additionally cooling and liquefying the cooled hydrocarbon stream in a main heat exchanger to produce a liquefied hydrocarbon stream. The method additionally comprises, prior to executing the stage d), cooling at least a part of the first stream of the liquid cooling agent by means of indirect heat exchange with at least a part of the throttled stream of the cooling agent in the first heat exchanger. The invention also relates to a hydrocarbon feed stream cooling unit.

EFFECT: effective and low-cost method and unit for eliminating two-phase input of a condenser of a warm combined cooling agent (WCCA) to the heat exchanger and excluding the pump for liquid WCCA.

14 cl, 7 dwg, 1 ex