BOIL-OFF GAS TEMPORARY STORAGE SYSTEM

摘要

Provided is a boil-off gas temporary storage system and, more particularly, is a boil-off gas temporary storage system which compresses boil-off gas at high pressure, temporarily stores the compressed boil-off gas in a boil-off gas absorbing tank, supplies the stored boil-off gas to a high-pressure gas transmission part and a high-pressure liquefied natural gas transmission part to recycle the boil-off gas, controls the pressure of a low-pressure liquefied natural gas cargo tank and a fuel liquefied natural gas tank of a ship to be filled with gas, and removes the necessity of a complicated and high-priced re-liquefaction device, in a method for removing the boil-off gas to depressurize the fuel liquefied natural gas tank of a ship to be filled with gas in the relatively high-pressure state before supplying the liquefied natural gas to a ship to be filled with gas.

主权项

1. A boil-off gas temporary storage system including a fuel tank pressure control valve 11 controlling a pressure of a fuel liquefied natural gas tank of a ship to be filled with gas 10 to discharge low-pressure boil-off gas, a cargo tank pressure control valve 21 controlling a pressure of the low-pressure liquefied natural gas cargo tank 20 storing or supplying low-pressure liquefied natural gas to discharge the low-pressure boil-off gas, and a compressor 30 compressing the low-pressure boil-off gas discharged from the fuel tank pressure control valve 11 and the cargo tank pressure control valve 21 to be converted into high-pressure boil-off gas, the boil-off gas temporary storage system comprising:
a boil-off gas absorbing tank 40 absorbing the high-pressure boil-off gas generated by the compressor 30 and storing the high-pressure boil-off gas and liquefied natural gas while being vapor-liquid separated from each other; an absorbing tank pressure control valve 41 controlling a pressure of the boil-off gas absorbing tank 40 to supply the high-pressure boil-off gas to a high-pressure gas transmission part 50; and a first liquefied natural gas pump 42 re-introducing and re-circulating a part of the liquefied natural gas discharged from the boil-off gas absorbing tank 40 into the boil-off gas absorbing tank 40.