Insulation system for floating marine structure

Abstract

Disclosed herein is a heat insulating system of a floating structure, and more particularly, a heat insulating system of a floating structure in which a heat insulating material is provided at at least one of a ballast tank, a trunk deck space, and a side passage way contacting the trunk deck to decrease a boil-off rate (BOR) occurring due to a heat transfer from an external region of a hull into an LNG storage tank.

Description

TECHNICAL FIELD[0001]The present invention relates to a heat insulating system of a floating structure, and more particularly, to a heat insulating system of a floating structure capable of decreasing a boil-off rate (BOR) by decreasing a heat transfer through at least one of a ballast tank, a trunk deck space, and a side passage way contacting a trunk deck.BACKGROUND ART[0002]Generally, natural gas is transported in a gas state through a ground or maritime gas pipe and is stored in an LNG carrier in a liquefied natural gas (hereinafter, referred to as ‘LNG’) state to be transported to remote consumption sites.[0003]The LNG obtained by cooling the natural gas at a very low temperature (approximately, −163° C.) has a volume decreased to approximately 1 / 600 compared to that of the natural gas in a gas state. Therefore, the LNG is very suitable for long distance transportation through the sea.[0004]The LNG may be transported through the sea while being carried in the LNG carrier to be ...

AI Technical Summary

Benefits of technology

[0041]According to the embodiments of the present invention, it is possible to control the temperature of the cofferdam to be temperature below 0° C. and provide the heat insulating material at at least one of the ballast tank, the trunk deck space, and the side passage way contacting the trunk deck, thereby decreasing the heat transfer from the cofferdam into the plurality of LNG storage tanks and decrease the heat transfer from at least one of the ballast tank, the trunk deck space, and the side passage way contacting the trunk deck into the plurality of LNG storage tanks, thereby decreasing the boil-off rate (BOR) generated due to the heat transfer.

[0042]That is, the embodiments of the present invention do not decrease the BOR by deforming the complex and expensive LNG cargo hold but fundamentally decrease the heat invasion into the LNG cargo hold by lowering temperature around the LNG cargo hold, thereby decreasing the BOR while maintaining the transportation efficiency of the LNG freight.

Problems solved by technology

Further, in the case of the membrane type LNG storage tank, if the cold LNG storage tanks are continuously installed, a temperature of steel between the cold LNG storage tanks is suddenly decreased, and therefore a brittle fracture may occur.

If the general steel is exposed to −60° C., the cofferdam is damaged due to low temperature brittleness.

However, if the very low temperature material is used, ship prices may suddenly rise.

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