LPG can be stored above ground, in pressurized or refrigerated tanks, or
underground, in rock mass, salt domes or aquifers. For large-scale storage,
underground storage has many advantages in terms of economy and safety.
Fortunately in Korea, the geology is suitable for underground rock cavern
storage. Since the construction of our Yeosu Terminal in 1983, the first
underground cavern storage in Korea, other LPG import terminals in Korea
have been of this type.
The critical point in storing LPG in rock mass is preventing leakage. In the
rock mass that forms an underground cavern, there are innumerable fissures
saturated with water that forms a constant water table. In order for the water pressure in the surrounding rock to be
greater than the pressure of the gas, and thus prevent the gas from escaping, the cavern must be located 120 meters or
more below sea level. Furthermore, the site must be located near the sea or large lakes, so that the underground water
level remains stable.
Deep underground, rock temperature is constant, at about 15℃. Since the pressure of LPG in the underground storage
(7 atmospheric pressure) remains lower than the hydrostatic pressure formed by the water table (12 atmospheric
pressure), it is possible to prevent leakage as the hydrostatic pressure of the surrounding rocks is higher than the pressure
of LPG stored in the underground cavern.