Liquid storage system and nonflammable gas supply method in liquid storage system

摘要

A liquid storage system capable of bringing the oxygen concentration in a gas phase space close to zero while maintaining the pressure of the gas phase space in a tank within a desired range. A liquid storage system includes a tank 10 capable of storing liquid fuel 20 therein, a gas phase space vertically above a liquid level 21 of the liquid fuel 20 stored in the tank 10, and the outside of the tank 10. Are operated according to a pressure difference between the gas phase space 22 and the atmospheric pressure, and the gas phase space 22 is operated according to the pressure difference between the gas phase space 22 and the atmospheric pressure. And a pressure control device 50 that restricts the pressure within a predetermined range including atmospheric pressure. The pressure control device 50 introduces air outside the tank 10 into the gas phase space 22 through the vent pipe 40 when the pressure in the gas phase space 22 falls below a predetermined lower limit value, and the pressure in the gas phase space 22 Gas rises above the predetermined upper limit value, the gas in the gas phase space 22 is discharged out of the tank 10 through the vent pipe 40. [Selection] Figure 1