LNG receiving station unshipping pipeline cold insulation system and cold insulation method thereof

A cold insulation system of an LNG receiving station ship unloading pipeline comprises an LNG receiving station storage tank, an immersed pump, a BOG compressor, a torch, an LNG tank ship, the LNG receiving station ship unloading pipeline, a user pipeline and a BOG backflow pipeline. Wherein the LNG receiving station unshipping pipeline and the user pipeline are in a sleeve form, the tube pass is the LNG unshipping pipeline, and the shell pass is the user pipeline. LNG flows out of the tank ship through the double-bus ship unloading pipeline and enters the LNG storage tank after flowing through the casing pipe pass, and the LNG in the storage tank enters the casing pipe shell pass after being pressurized through the immersed pump and then enters a user pipeline. A part of BOG in the storage tank flows through the BOG compressor and enters the storage tank on the ship through the BOG return pipe so as to maintain the pressure of the BOG, and the redundant part of the BOG enters the torch to be combusted. The c