Wharf platform pipeline cold insulation system and method of offshore LNG receiving station

Abstract

The invention provides a wharf platform pipeline cold insulation system and method of an offshore LNG receiving station. The system is provided with ship unloading arms, ship unloading branch pipes, ship loading arms, ship loading branch pipes, a ship loading gas return arm and a ship unloading gas return arm. The ship unloading branch pipes are provided with ship unloading branch pipe cutoff valves and are further connected with ship unloading evacuation branch pipes and ship unloading emptying branch pipes. The ship loading branch pipes are provided with ship loading branch pipe cutoff valves and are further connected with ship loading evacuation branch pipes and ship loading emptying branch pipes. The ship unloading evacuation branch pipes and the ship loading evacuation branch pipes communicate to a wharf emptying tank through an evacuation main pipe in a converged manner. The ship unloading emptying branch pipes and the ship unloading emptying branch pipes communicate to the wharfemptying tank through an emptying main pipe in a converged manner. The wharf emptying tank communicates with a BOG gas return main pipe through a wharf emptying tank gas phase balance line. The system has a ship unloading mode, a non-ship-unloading natural evaporation cold insulation mode and a non-ship-unloading pump circulating cold insulation mode, and cold insulation feasibility and reliability of a wharf platform of the offshore LNG receiving station can be guaranteed.

Description

technical field [0001] The invention relates to a cold preservation method for a wharf platform low-temperature pipeline of an offshore LNG receiving station, and provides isolation facilities, instrument control, safety interlocking and discharge facilities required for the implementation of the method. Background technique [0002] Liquefied natural gas has the characteristics of high calorific value, high efficiency, low pollution, and strong environmental friendliness. It is a high-quality energy source with wide applications. With the popularity of liquefied natural gas applications (hereinafter referred to as "LNG") and the continuous development of the LNG industry, there are more and more types of LNG application infrastructure. In addition to conventional LNG receiving terminals, many different forms of LNG receiving terminals have emerged. And regasification infrastructure, floating LNG regasification unit (hereinafter referred to as "FSRU") is one of them. FSRU i...

AI Technical Summary

Problems solved by technology

[0005] For offshore LNG receiving stations, after LNGC completes unloading and leaves the port, it is still necessary to keep the unloading pipeline in a cold state to avoid the large temperature difference between the upper and lower surfaces of the low-temperature pipeline caused by the reheating process. Usually, FSRU can provide low-pressure LNG. However, the FSRU does not have an interface for the low-pressure LNG to circulate to the FSRU after passing through the unloading pipeline for cooling.

Since the process flow on the FSRU also cannot be individually retrofitted for this function

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