US 11,959,593 B2Granted

Method for detecting a leak in a sealed and thermally insulating tank

AssigneeGaztransport Et Technigaz

InventorsBertrand Bugnicourt, Laurent Spittael, Nicolas Dupont, Jean-Yves Le Stang

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Abstract

The invention relates to a method for detection of a leak from a tank for liquid gas, said tank comprising a membrane surrounding the liquid gas, the membrane being surrounded by an insulation space which separates the membrane from a wall, the insulation space being filled an inert gas which is injected and extracted by at least one duct. The detection method comprises the following steps: determining 921 a first variation of mass of inert gas ΔM1 between two moments by measuring the gas added and removed by the duct; calculating 922 a second variation of mass of inert gas ΔM2 corresponding to a difference between two masses of inert gas measured in the insulation space; and comparing 931 the first variation with the second variation, and triggering an alarm if a difference E1 between the first variation and the second variation of mass of inert gas is greater than a first threshold S1.

Claims22

Dependent claims

A detection method for detecting a leak from a sealed, thermally insulating tank for liquid gas, said tank comprising a sealing membrane surrounding the liquid gas, the sealing membrane being surrounded by an insulation space which separates the sealing membrane from a sealed support wall, the insulation space being filled with solid, thermally insulating materials and an inert gas, the insulation space having at least one injection duct arranged to inject the inert gas and at least one extraction duct arranged to extract the inert gas, the detection method comprising the following steps:

injecting inert gas into the insulation space;
removing inert gas from the insulation space;
determining a first variation of mass of inert gas between a first moment and a second moment, the first variation corresponding to the resultant of the total masses of inert gas added by the injection duct and removed by the extraction duct, between the first moment and the second moment;
determining a first mass of inert gas in the insulation space at the first moment and second mass of inert gas in the insulation space at the second moment by means for measuring the pressure and temperature in a free volume of the insulation space;
calculating a second variation of mass of inert gas between the first moment and the second moment, corresponding to the difference between the second mass and the first mass of inert gas;
and
comparing the first variation of mass of inert gas with the second variation of mass of inert gas, and triggering an alarm if a difference between the first variation and the second variation of mass of inert gas is greater than a first threshold.

4 more elements

An installation for storage of liquid gas comprising a sealed, thermally insulating tank which comprises a sealing membrane surrounding the liquid gas, the sealing membrane being surrounded by an insulation space which separates the sealing membrane from a sealed support wall, the insulation space being filled with solid, thermally insulating materials and an inert gas, the insulation space having at least one injection duct arranged to inject the inert gas and at least one extraction duct arranged to extract the inert gas,

wherein the tank comprises at least one pressure sensor and a plurality of temperature sensors which are configured to determine the pressure and the temperature of the inert gas enclosed in a free volume of the insulation space,
wherein the installation comprises flow measurement devices to measure a flow of inert gas in the injection duct and in the extraction duct, and at least one leak detection device, the at least one leak detection device being configured to:
determine together with the flow measurement devices a first variation of mass of inert gas between a first moment and a second moment, with the first variation corresponding to the resultant of the total masses of inert gas added by the injection duct and removed by the extraction duct between the first moment and the second moment;
determine a first mass of the inert gas in the insulation space at the first moment and a second mass of inert gas in the insulation space at the second moment based on pressure and temperature measurements carried out by the at least one pressure sensor and the plurality of temperature sensors in a free volume of the insulation space;
calculate a second variation of mass of inert gas between the first moment and the second moment corresponding to the difference between the second mass and the first mass of inert gas;
and
compare the first variation of mass of inert gas with the second variation of mass of inert gas, and
trigger an alarm if a difference between the first variation and the second variation of mass of inert gas is greater than a first threshold.

5 more elements

Dependencies are inferred from the claim text.