System and method for temperature reduction and pressure stabilization of liquefied natural gas storage tank

Abstract

The invention provides a system for temperature reduction and pressure stabilization of a liquefied natural gas storage tank, comprising a liquid nitrogen delivery device, a liquefied natural gas storage tank and a discharge duct, wherein the liquefied natural gas storage tank is internally provided with a heat exchange tube; the inlet of the heat exchange tube is connected with the liquid nitrogen delivery device through a pipeline, and the outlet of the heat exchange tube is connected with the discharge duct through a pipeline; the liquefied natural gas storage tank is provided with a pressure sensor connected with the liquid nitrogen delivery device; the discharge duct is internally provided with a vaporizer; and the liquid nitrogen delivery device is externally connected with a liquid nitrogen source. The invention also provides a method for temperature reduction and pressure stabilization of the liquefied natural gas storage tank, which is realized by the system. In the system provided by the invention, the temperature and pressure conservation functions of the liquefied natural gas storage tank can be realized through the arrangement of the heat exchange tube in the liquefied natural gas storage tank, thus the structure is simple and easy to understand, and the system is suitable for various liquefied natural gas storage tanks and has low design cost and the like.

Description

Technical field [0001] The invention relates to liquefied natural gas storage technology, in particular to a temperature-reducing and stabilizing system and method for liquefied natural gas storage tanks. Background technique [0002] When LNG is in use, it is generally stored in LNG storage tanks (ie, LNG storage tanks); while in the use of LNG storage tanks, as the LNG storage tanks are used for longer, they will absorb heat from the atmosphere , So that the liquefied natural gas is vaporized into BOG gas (ie boil-off gas or gaseous natural gas), which leads to an increase in the pressure in the liquefied natural gas storage tank, resulting in potential safety hazards. [0003] In view of the above problems, the current solutions mainly include the following four: (1) Directly discharge BOG gas and burn it on site to reduce the pressure in the LNG storage tank; (2) Directly incorporate BOG gas into the pipeline network for use; 3) After the BOG gas is exported to pressurized liq...

AI Technical Summary

Problems solved by technology

Although these two technologies can initially solve the problem of potential safety hazards, there are defects in these two technologies: direct combustion of BOG gas violates the purpose of storing liquefied natural gas itself, and is not suitable for long-term storage of liquefied natural gas storage tanks

However, the process of changing the structure of the storage tank with this technology is more complicated, and the manufacturing of this storage tank requires more costs, and it is not widely used

In addition, this technology does not completely avoid the generation of BOG gas, so it is not suitable for LNG storage tanks that require long-term storage, and is only suitable for LNG carriers

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