BOG liquefaction recycling system for liquefied natural gas

Abstract

The invention discloses a BOG liquefaction recycling system for liquefied natural gas. The BOG liquefaction recycling system comprises a low-temperature liquid storage tank, an LNG filter, a primary jet mixer, a secondary jet mixer, an LNG storage tank, a BOG pressure monitoring device and a DCS control system. When the DCS control system judges that a BOG pressure value exceeds a preset value, afirst stop valve is closed, a second stop value, a drain valve and a check value are opened, and gaseous BOG generated in the LNG storage tank and low-temperature liquid in the low-temperature liquidstorage tank are led into the primary jet mixer together for primary cooling liquefaction; then, cooling liquid output by the primary jet mixer and LNG of an LNG input end are led into the secondary jet mixer together for secondary cooling; finally, BOG is completely liquefied and flows back into the LNG storage tank. Thus, BOG liquefaction recycling is realized, and therefore BOG zero emission isreached. The BOG liquefaction recycling system does not need equipping a compressor and a pump and has the advantages of low cost of investment, simple process system and low operational and maintenance cost.

Description

technical field [0001] The invention relates to a BOG liquefaction treatment technology in liquefied natural gas, in particular to a BOG liquefaction recovery system for liquefied natural gas. Background technique [0002] Liquefied Natural Gas (LNG) is a high-quality clean energy. Its volume is about 1 / 625 of the volume of gaseous natural gas. The main component is methane. The rapid growth trend has been widely used in industrial fields such as city gas, power generation, fuel vehicles, and ships. At present, my country has built a large number of receiving terminals such as LNG receiving stations, natural gas liquefaction stations and LNG filling stations, which is conducive to the stable supply of energy and the diversification of energy in my country. [0003] The LNG storage tank is the core equipment of the LNG receiving terminal, which belongs to the low-temperature, atmospheric pressure storage tank. During storage, transportation and operation, since LNG has an e...

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Problems solved by technology

[0005] (1) After reheating, send to the flare system or directly vent: Although this method is simple, it is less safe and has no economic benefits

[0006] (2) Filling the thermal insulation layer of the storage tank with BOG: Although the sensible heat of BOG is used to improve the thermal insulation efficiency of the thermal insulation layer, the operability is poor; for the BOG generated by large LNG storage tanks, only part of the BOG can be used, low reuse rate

my country has not yet conducted special research on the LNG high calorific value adjustment process

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