Storage tank for cryogenic liquefied gas
AssigneesGaz de France, Applied Thermodynamics & LNG Service
InventorJean R. Guilhem
Life of this patent
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Abstract
The invention is related to a tank designed to contain a cryogenic liquefied gas and formed in addition to the main tank by two other tight walls. In the upper part of this tank an aperture duct connects the ceiling of the tank to the exterior of the tank, a holder supporting a device sensing in various areas wall temperatures of the tank, can be fitted into this aperture duct, a remote temperature sensor is actually hold by this support and is introduced into the tank. The invention finds an application as a means to easily localize leaking failures of the intermediate wall.
Claims7
In a tank construction adapted to contain cryogenic liquefied gas such as liquefied natural gas including a first interior wall providing a primary barrier and defining a tank chamber for containing liquefied gas under pressure, a second intermediate wall providing a secondary barrier and spaced outwardly of said first wall and providing a primary space between the first and second walls, a third exterior wall outwardly of the second wall and providing a secondary space between the second and third walls, thermal insulating material filling said primary space, thermally insulating material filling the secondary space, a line communicating the tank chamber with an inert gas supply adapted, after the liquefied gas has been unloaded from the tank chamber, to push any remaining liquefied gas out of the tank chamber, and a line communicating the secondary space with a supply of safety gas, the safety gas having, under the pressure prevailing in the primary space, a sublimation temperature lower than the temperature prevailing in service within said secondary space and higher than the primary barrier temperature at said chamber prior to warming-up of the primary barrier, the provision of:
- a temperature sensing means in said tank chamber for sensing temperatures at selected areas of said first wall after unloading of said liquefied gas;
- and means for introducing and supporting said temperature sensing means in said tank chamber.
In a method of locating failures in an intermediate wall of a multiple-wall tank construction in which a first interior wall provides a tank chamber, an intermediate second wall defines with the the first wall a continuous space around said first wall, and a third wall which defines a continuous space around the second wall, and lines adapted to carry fluid are in communication with said second space and said tank chamber, including the steps of:
- unloading the contents in the tank chamber through one of said lines;
- introducing safety fluid into said secondary space;
- said safety fluid being adapted to penetrate and pass through any failures in said second intermediate wall to cause the growth of frost on the face of the first wall defining said primary space;
- and
- measuring the temperature difference between the areas on the first wall covered by frost and those without frost to identify the location of the failures in the second wall.
Dependencies are inferred from the claim text.