Quenching and liquid hammering of LNG storage tanks

is a storage tank specially used for storing liquefied natural gas. LNG storage tank is a sandwich storage tank. Because the temperature of liquid natural gas is lower than -162 degrees Celsius, LNG storage tank is also a cryogenic storage tank. In order to meet the requirements of LNG, the LNG storage tank must be jacketed to ensure the temperature inside the tank.

Due to the intermittent refueling of LNG vehicles, the equipment in the filling station is repeatedly opened and closed, and the opening or closing of valves or pumps causes the liquid flow velocity in the pipeline to change suddenly, sometimes it may be a drastic change, and the momentum of the liquid also changes. The pressure in the pipe rises or falls rapidly, and accompanied by the sound of liquid hammering. This phenomenon is called liquid hammering. Liquid hammer will cause a drastic change in the pressure in the pipeline, and the pressure rises suddenly. In severe cases, it can cause the pipeline to burst. Rapid pressure drop can cause negative pressure in the pipeline, which will cause the pipeline to be unstable and cause pipeline vibration. Quenching refers to the phenomenon of rapid cooling of pipes or equipment in a short period of time. Due to the intermittent operation of the LNG filling station, during the process of suddenly starting the filling or unloading after the system is running, especially during the start of the operation, rapid cooling may occur. The rapid cooling phenomenon will form a temperature gradient at the top and bottom of the pipe, which will cause the pipe to bend between the two supports. Due to the large flexural stress, the pipe will also be in danger of breaking.

Cryogenic storage tank supplier suggest that in order to prevent the occurrence of rapid cooling and water hammer, the design should consider the cold shrinkage of the pipeline caused by the low-temperature characteristics of the medium in the pipeline, and set a reasonable pipeline compensation method; Pre-cooling of equipment and pipelines; during operation, the opening and closing speed of pumps and valves must not be too fast. It is recommended to use valves with longer strokes, such as cryogenic shut-off valves, to prevent sudden pressure rise and fall.