JPS6350271B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an underwater oil storage tank, and more particularly to an underwater oil storage tank suitable for storing relatively high temperature oil.

Conventionally, when temporarily storing crude oil extracted from offshore oil fields, it has been convenient to install an oil storage tank in the ocean at close range. It is preferable to install the tank underwater, and various types of underwater oil storage tanks are available.

By the way, crude oil contains various components, and some types of crude oil contain components that solidify unless kept at a certain temperature.Such crude oil is stored in underwater oil storage tanks. In such cases, heat retention measures such as steam pipes are installed.

In this case, if the temperature difference between the stored oil temperature and the sea temperature is about 30 to 35 degrees Celsius, there will be relatively little problem, but if this temperature rises to about 50 degrees Celsius or more, the side walls of the concrete oil storage tank will be severely damaged. There is a risk of cracking due to large thermal stress acting on the material.

In order to avoid this problem, an oil storage tank has been proposed that has a double-walled integral structure and a thermal insulation material is filled between the inner and outer walls. There was a problem.

In addition, even if the oil storage tank is simply a double structure, if the inner tank that stores high-temperature oil is improperly placed, the temperature distribution will be omnipresent, and this will cause thermal stress to concentrate in a specific location. There was a problem that cracks appeared that could cause the tank to lose its functionality.

This invention was made in view of the conventional problems as described above, and its purpose is to maintain relatively high temperature oil, etc. at a constant temperature, and to reduce the thermal stress applied to the tank side wall even when stored. To provide an underwater oil storage tank that can be significantly relaxed and the omnipresence of thermal stress can be made unnecessary, and can be stably submerged in the sea.

In order to achieve this object, the present invention provides an underwater oil storage tank that includes a plurality of outer walls having a plurality of convex portions bent in an arc shape, and a partition wall disposed in the axial direction. It has a double shell structure of an outer shell caisson having compartments and a cylindrical inner shell oil storage tank disposed in each of the compartments, and a side wall of the inner shell oil storage tank disposed within the outer shell caisson. extends downward and is integrally fixed to the bottom plate of the outer shell caisson, and integrally locks the extended side wall with the outer wall and the partition wall,
A filler for reducing temperature stress is interposed in each gap in the compartment.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

FIGS. 1 and 2 show an embodiment of an underwater oil storage tank according to the present invention.

The underwater oil storage tank shown in the drawing is installed underwater 10, the bottom part is supported by slightly penetrating into the seabed 12, and the upper end part protrudes to the sea surface 14, and is made of concrete with reinforcing bars placed at appropriate locations. It has the characteristics shown below.

In other words, the underwater oil storage tank has a plurality of convex portions 1 which are bent in an arc shape and arranged inside the same circumference.
6, 16..., and is provided with an outer wall 18 having a petal-shaped cross section, and is formed into a cylindrical shape as a whole, the lower end is closed with a bottom plate 20, and the upper end is a cylindrical inner shell oil storage tank to be described later. It has a double shell structure consisting of an outer shell caisson 24 to which a top plate 22 having a circular through hole 21 with approximately the same diameter is fixed, and a cylindrical inner shell oil storage tank 26.

A partition wall 28 is arranged in the axial direction of the outer shell caisson 24, and a plurality of compartments 30, 30... are defined by the partition wall 28 and the outer wall 18, and the overall cross-sectional shape is honeycomb-shaped. There is. Above compartment 3
The inner shell oil storage tanks 26, 2 are inside the inner shell oil storage tanks 26, 2.
6... are arranged respectively, and the side walls 32 of the inner shell oil storage tanks 26, 26... are extended downward and integrally fixed to the bottom plate 20 of the outer shell caisson 24, and furthermore, the side walls 32 of the inner shell oil storage tanks 26, 26... The section is also integrally locked with the outer wall 18 and the partition wall 28 by a slope plate 34 fixed between the outer wall 18 or the partition wall 28 and the bottom plate 20.

Further, the upper end surface of the inner shell oil storage tank 26 is inserted into the through hole 21 so as to be substantially flush with the top plate 22 of the outer shell caisson 24, and preferably, the inner circumferential surface of the through hole 21 An elastic material such as rubber is installed between the inner shell oil storage tank 26 and the side wall 32 of the inner shell oil storage tank 26.

Further, the top plate 22 is provided with openings at appropriate locations for filling with a filler material, which will be described later, and the inner shell oil storage tank 26 is provided with an opening for inserting and removing all the oil to be stored.
Provide an outlet for each.

After the underwater oil storage tank having the above-mentioned configuration is towed to the installation location, the installation location on the seabed 12 is excavated flat by an appropriate means, and water is poured into the tank and the tank is submerged.
A filler 36 for reducing temperature stress is filled in the gap between the inner shell oil storage tank 26 and the outer shell caisson 24 in 0, 30, . . . .

This filler material 36 may be, for example, earth and sand excavated from the nearby seabed or earth and sand transported by a tugboat.
Furthermore, these earth and sand are mixed with an insulating substance, and preferably have a relatively high specific gravity.

The filler 36 fills each inner shell oil storage tank 26.
It is filled so as to cover the side walls 32 and the bottom except for the top end surface.

As a result, the oil storage tank can be sunk with its upper end protruding above the sea surface 14, as shown in FIG. 2, and then oil 38 is inserted into each tank 26, 26, and stored therein.

Now, in the underwater oil storage tank having the above-mentioned configuration, even if the oil 38 with the temperature gradient with the seawater is about 50°C or more is stored, the tank itself is a double shell consisting of the outer shell caisson 24 and the inner shell oil storage tank 26. The inner shell oil storage tanks 26, 26, which have a high-temperature oil 38 structure and store high-temperature oil 38, have no filler material 3 except for the upper end surface.
6, the temperature stress applied to the outer wall 18 and bottom plate 20 of the outer shell caisson 24 can be significantly alleviated, and the occurrence of cracks that would cause the oil storage tank to lose its function is almost completely eliminated. can.

In addition, an inner shell oil storage tank 2 containing oil 38 is also provided.
6, 26... can be arranged in an extremely well-balanced manner as is clear from Figs. The omnipresence of temperature stress with temperature distribution is also eliminated.

Furthermore, since the part where the filler 36 is filled at the bottom of the tank is provided at approximately 1/3 of the total height of the tank, it is possible to sink the tank and store the oil 38 in an extremely stable state. .

Furthermore, the outer wall 18 of the outer shell caisson 24 is
Since the entire structure is curved into an almost cylindrical shape, it can strongly resist underwater waves or currents, and the cross-sectional shape of the outer wall 18 and the partition wall 2
8 has a honeycomb shape, so it has an extremely strong structure against horizontal external forces applied to the oil storage tank.

In the above embodiment, the upper end of the oil storage tank was installed so as to protrude above the sea surface 14, but
It goes without saying that this can be installed completely immersed underwater.

Furthermore, the tank of the present invention can of course store not only oil but also high-temperature liquid or fluid substances such as high-temperature liquefied gas.

Furthermore, the upper end surface of the inner shell oil storage tank 26 is not only used as the top plate 22 of the outer shell caisson 24, but also is completely located inside the outer shell caisson 24, so that the entire circumference of the oil storage tank 26 is surrounded by the filling material 36. Of course, it is also possible to cover it with

As described above in detail in the embodiments, in the underwater oil storage tank according to the present invention, thermal stress applied to the side wall of the tank can be significantly alleviated, the heat distribution is made uniform, and furthermore, the underwater oil storage tank according to the present invention can be This makes it possible to stably deposit the material.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an embodiment of an underwater oil storage tank according to the present invention, and FIG. 2 is a vertical cross-sectional view thereof. 10...Under the sea, 12...Under the sea, 14...Sea surface, 16...
Convex portion, 18...Outer wall, 20...Bottom plate, 21...Through hole, 2
2... Top plate, 24... Outer shell caisson, 26... Inner shell oil storage tank, 28... Partition wall, 30... Compartment chamber, 32... Side wall, 34... Inclined plate, 38... Oil.

Claims (1)

[Claims] 1 In an underwater oil storage tank made of concrete and installed in the sea with the bottom supported on the seabed, the oil storage tank is defined by an outer wall having a plurality of convex portions bent in an arc shape and a partition wall arranged in the axial direction. It has a double-shell structure consisting of an outer shell caisson with a plurality of compartments, and a cylindrical inner shell oil storage tank located within each compartment, with the side wall of the inner shell oil storage tank extending downward. and is integrally fixed to the bottom plate of the outer shell caisson, and integrally locks the extension side wall, the outer wall, and the partition wall, and is installed in the gap between the inner shell oil storage tank and the outer shell caisson in the compartment. Each of these is an underwater oil storage tank characterized by having a filler interposed therein for reducing temperature stress.