Briefly Describe the Filling Matters of LNG Storage Tanks

Generally, some dangerous gases are stored in lng storage tanks. Once leakage occurs, the consequences are unimaginable. Therefore, for lng storage tanks, its safety requirements are also very high. These dangerous storage equipment, its The danger is always present, and the same is true for some other related equipment. Next, let me tell you about the filling precautions of lng storage tanks.
(1) The LNG storage tank of the new gasification station must be purged and pre-cooled with nitrogen before the initial use. The maximum purge pressure should be equivalent to 50% of the maximum operating pressure, or less.
(2) When filling liquid for the first time, precautions should be taken
①Open the upper and lower inlet valves, and fill the top and bottom together. Open the liquid overflow valve at the same time, and discharge the gas in the storage tank until the LNG gas is discharged, and immediately close the overflow valve;
②When filling to more than 50% of the volume of the lng storage tank, the lower inlet valve should be closed;
③ When filling to 85% of the volume of the storage tank, close the advance valve and stop filling for 3 minutes to calm the liquid level in the tank, and then open the advance valve to continue filling until there is liquid overflowing from the tank. When the flow port valve flows out, immediately close the overflow valve, stop filling and close the progress valve;
④When starting to fill with liquid, you should loosen the joints at both ends of the liquid level gauge, open the liquid level display liquid phase valve and the liquid level display gas phase valve, and check whether there is any moisture in the discharged air flow.
If there is moisture, it should continue to be discharged, until the discharge is stopped when there is no moisture. Tighten the joints at both ends of the level gauge, and close the balance valve to keep the level gauge in normal working condition.
(3) Refill procedure
①After the initial filling of the LNG storage tank, when refilling, the gas phase pressure in the storage tank should be reduced as much as possible;
②Fill up and down together. When the liquid level gauge shows about 50% full, the lower inlet valve should be closed. When the filling reaches 85%, the advanced liquid valve should be closed, and the filling should be stopped for 3 minutes to make the liquid in the tank When the surface is calm, then open the progress valve to continue filling, until the liquid is discharged from the overflow valve, close the overflow valve to stop filling, and close the progress valve at the same time;
③ During the observation of the filling process, the pressure gauge and the liquid level gauge should try to maintain a pressure difference of 0.2 MPa. (If the pressure rises above the filling delivery pressure or is close to the safety valve release pressure, it is necessary to open the gas discharge valve to discharge the gas phase in the storage tank in an appropriate amount).
The above three points are the relevant analysis of the precautions for lng storage tank filling. I also hope that everyone can remember the above relevant procedures and strictly implement the above operations, which is also for the safety of everyone’s life.