Abstract An off-shore storage tank for liquefied gas has an outer shell, of which at least the lower part, which is immersed in the water, is made of solid concrete, sufficiently thick and heavy when in place to sink in the water even when empty, and is lined with thermal insulation such that in operation, when storing liquefied gas at cryogenic temperatures, the said lower part is maintained at a surface temperature below the freezing point of the water in which it is immersed so that a coating of frozen water is formed on the tank which acts as an additional seal for the concrete. Other features are that the upper part of the tank wall is sufficiently thinner than the lower part to provide an external annular step constituting a walkway around the tank, and the provision of tangential piers as part of the tank structure at points opposite to and adjacent the shore line. The tank is preferably made initially light enough in weight so that it can be floated to its location of use, then further concrete or other loading is added to sink the tank to the sea bed.
A storage container for liquefied gas and adapted for partlysubmerged installation off-shore, comprising a. an outer shell at least the lower part of which is of bulk concrete, said outer shell being of sufficient weight to overcome the floatation forces of the surrounding water when the tank is empty, b. thermal insulation within the outer shell, the lower part of which is of a thickness selected such that in operation the outer surface of said lower part of the outer shell is at a temperature at least as cold as the freezing point of the surrounding water, whereby an outer layer of frozen water is formed which will act as a seal for the concrete.
Claim 2
Dependent Claim
115 words
A storage container for liquefied gas and adapted for partlysubmerged installation off-shore, comprising a. an outer shell at least the lower part of which is of bulk concrete, said outer shell being of sufficient weight to overcome the floatation forces of the surrounding water when the tank is empty, b. thermal insulation within the outer shell, the lower part of which is of a thickness selected such that in operation the outer surface of said lower part of the outer shell is at a temperature at least as cold as the freezing point of the surrounding water, whereby an outer layer of frozen water is formed which will act as a seal for the concrete.
Claim 3
Dependent Claim
33 words
A storage container according to claim 1, c. the upper part of said thermal insulation, above the water line being thicker than the lower part so as to maintain ''''boil-off'''' at a minimum.
Claim 4
Dependent Claim
53 words
A storage container according to claim 1, c. wherein tangential piers are provided on points opposite to and adjacent to the shore-line for accommodating a liquefied gas tanker on the sea side and the equipment necessary to regasify and/or pump the liquefied gas from the storage tank to shore on the shore side.
Claim 5
Dependent Claim
41 words
A storage container according to claim 1, c. wherein the upper part of said outer shell is thinner than said lower part, and the difference in thickness between these parts provides an external annular step constituting a walkway around the container.