What are the signs observed at the site of an outlet leak in an LNG storage tank, and how should it be dealt with urgently?

No one replied, so I had to come up with a rough direction on my own. I’m not sure if it’s correct; please correct me if I’m wrong. First, shut down the facility; isolate the storage tanks from the facility area, except for the flare stack. Monitor changes in the pressure of the storage tanks, establish a safety zone, and prohibit any potential sources of fire from entering this zone, including the prohibition on bringing mobile phones. Wear full protective gear and a respirator. Starting from the leakage point, construct a temporary barrier using sand and soil around it within a radius of 5 meters, relying on existing concrete barriers. Place metal trays beneath the leakage point to create a double-layer barrier for collecting the leaked LNG. Use wheeled foam fire extinguishers to cover the leaked LNG inside the temporary barrier and on the trays with high-concentration foam, thereby enabling its safe and controlled vaporization. Prepare metal shields as well to prevent spraying at the LNG leakage site. After all this is done, send someone wearing full protective gear and a self-contained breathing apparatus to enter the area under close monitoring. They should close the valves, install clamps to stop the leak, and monitor the tank pressure to see if the leak can be successfully sealed. If not, transfer the contents of the tank to another container and depressurize it.

Personal opinion: If there is a severe leak at the valve at the base of the storage tank, it’s definitely necessary to spray in a low-temperature liquid. If tank dumping is not possible at this time, the safety vent valve of the storage tank should be opened, personnel should be evacuated, warning lines should be set up, and smoking and open flames should be prohibited in the vicinity to allow the tank to release its vaporized contents on its own!

We have a water injection system that injects water in case of a leak to prevent the spread of liquid hydrocarbons.

Bro, are you sure the LNG storage tank can be filled with water? ? :For large storage tanks, both liquid inlet and outlet are located at the top of the tank; leaks generally do not result in uncontrolled flow of liquid. If liquid leaks from the bottom of the tank, or if there is a leak in the valves at the base, it becomes quite difficult to control the situation. It’s better to transfer the liquid from the tank as soon as possible – attempting to seal the leak while pressure is still present is also tricky. Due to the low temperatures, if nothing else can be done, the only option is to isolate the area and wait for the leak to stop on its own. The tanks at filling stations are not very large, so the amount of liquid stored is limited; therefore, the loss caused by a leak isn’t significant.