JPS6080993A - Low temperature liquefied gas carrier - Google Patents

Abstract

PURPOSE:To enable existing LNG tankers to conform to the IMO code without need for carrying out a large conversion by fixing cross members made of normal steel between secondary protective walls made of low-temperature steel, of an LNG tank, and circulating hot water through a space formed by said secondary protective walls and said cross members. CONSTITUTION:In an existing LNG tanker, in which a secondary protective wall 2 for an LNG gas tank 1 is made of low-temperature steel while cross members 3 fixed on its inner surface are made of normal steel, an isolation part plate 4 made of low-temperature steel is additionally provided between the cross members 3 and the tank 1, being fixed to the inner end face flanges 3a of the cross members 3. Hot water is circulated through a space formed by the secondary protective wall 2, the isolation part plate 4, and the cross members 3. Thereby, a low-temperature breakage of the cross member made of normal steel can be prevented while enabling an existing LNG tanker to conform to the IMO code without need for carrying out a large conversion.

Description

[Detailed description of the invention] The present invention relates to a low temperature liquefied gas carrier.

Conventionally, the secondary barrier walls of tanks in low-temperature liquefied gas carriers have been made of low-temperature steel (Class 08 steel) according to regulations, but the aggregates fixed to their inner surfaces are made of ordinary steel (CA class steel). However, recently, the existing low-temperature liquefied gas carrier, 1M0 (engineering nt@national
Maritime Organization')
There is a growing demand for ships to comply with existing ship codes, and there is a fear that ships that do not comply with the above codes will not be allowed to enter port. By the way, according to this engineering MO code, the aggregate for the secondary defense wall is also required to be able to withstand low temperatures. Therefore, in order to make existing ships comply with the IMO code, the aggregate for the secondary defense wall must be made from ordinary materials. Steel must be replaced with low-mix @, and it is practically impossible to replace all the aggregate of the secondary barrier around the tank.

Therefore, the present invention enables existing ships to be integrated without replacing aggregates.
The purpose of the present invention is to provide a low-temperature liquefied gas carrier that can comply with the MO Code.

That is, the present invention is applicable to existing low-temperature liquefied gas carriers in which low-temperature steel is used for the secondary barrier of the low-temperature liquefied gas storage tank, and ordinary steel is used for the aggregate fixed to the inner surface of the secondary barrier. , a low-temperature steel plate that isolates the aggregate from the storage tank is fixed to the inner end surface of the aggregate, and hot water is supplied to a space chamber formed between the low-temperature steel plate and the secondary barrier. This is a low-temperature liquefied gas carrier characterized by having hot water supply pipes connected to it. According to this configuration, when low-temperature liquid leaks from the storage tank, it spills over the low-flow steel plate, and the leaked low-temperature liquid becomes aggregate. V! ：In addition to preventing direct contact, it is also reported that the temperature of the aggregate itself will drop to extremely MIA due to the supply of flooded water into the space chamber. Therefore, without replacing the aggregate, the existing It is possible to make the low-temperature liquefied gas carriers comply with the Engineering MO Code.

Hereinafter, one embodiment of the present invention will be described based on 121 pages.

The drawing shows low-wetness steel on the secondary barrier (e.g. hold bulkhead, hull shell) (2) of a low-temperature liquefied gas storage tank (1), and a large number of T-shaped bones fixed to the inner surface of the secondary barrier (2). This figure shows the main part of the hold of an existing (7) low-temperature liquefied gas carrier, in which ordinary steel is used as material (3). This item contains aggregate (
3) It is designed to prevent the temperature from dropping excessively. That is, on the 7 tank surfaces (3a) of each aggregate (3), there is a low-temperature steel plate (thin plate, for example, about 3.2 WM thick) that isolates all aggregates (3) from the storage tank (1). (4) is fixed so that it hangs parallel to the secondary barrier (2), and the closed space chamber (5) formed between the low-temperature steel plate (4) and the secondary barrier (2) is A hot water supply pipe and a drain pipe (both not shown) for supplying and discharging high temperature water (for example, high temperature JJ water) are connected to this space chamber (5). Therefore,
The low-temperature steel plate (4) may have reduced the shape of another secondary barrier.
is composed of a number of pieces of a predetermined size connected together, and the end portion is the flange surface (3a) of the material (3).
Alternate layers are welded on top. , Also, in the web (3b) of the aggregate (3), LA f! A plurality of communication holes for high temperature water are provided at appropriate locations.

In the above configuration, if low temperature liquid leaks from the storage tank (1), if high temperature water is supplied into the space chamber (5) via the hot water supply pipe, the aggregate (3) will be warmed and the bones will be heated. Material (3)
It is possible to prevent a temperature drop of +h.

According to the above configuration, when low-temperature liquid leaks from the storage tank, the low-temperature steel plate prevents the leaked low-temperature liquid from coming into direct contact with the aggregate on the first floor, and hot water is supplied into the space chamber. It is possible to prevent the temperature of the aggregate itself from dropping excessively and to make existing low-temperature liquefied gas carriers comply with the IMO code without having to replace the aggregate.

[Brief explanation of the drawing]

The drawing is an enlarged sectional view of a main part of an embodiment of the present invention. (Former...low wet liquefied gas storage tank, (2)...secondary barrier, (3)...aggregate, (3&)...7 tank surface,
(4)...For low temperature (-board, (5)...Space room agent Yoshihiro Morimoto

Claims (1)

[Claims] ■. An existing low-temperature liquefied gas storage tank in which low-temperature steel is used for the secondary barrier and ordinary steel is used for the aggregate fixed to the inner surface of the secondary barrier. In the carrier ship, a low-temperature steel plate that isolates the aggregate from the storage tank is fixed to the inner end surface of the aggregate. A low temperature liquefied gas carrier characterized in that a hot water supply pipe for supplying hot water is connected to the space chamber formed between the low temperature steel plate and the secondary barrier.