JPS6350270B2 - - 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 a close distance. It is preferable to install the tank underwater, and various underwater oil storage tanks have been proposed.

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 exceeds about 50 degrees Celsius, 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.

To avoid this problem, oil storage tanks have been proposed that have a double-walled integral structure with insulation material filled between the inner and outer walls. I had a problem with my sexuality.

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 also the problem of cracks appearing 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 alleviated and buffered against the omnipresence of thermal stress, thereby making it unnecessary to use heat insulating materials and capable of being stably towed to an installation site or submerged in the sea. It's there.

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 consisting of an outer shell caisson having compartments, and a cylindrical inner shell oil storage tank disposed in each of the compartments, and each compartment has an inner shell oil storage tank. It is characterized in that a buffer member for supporting from the side is provided, and a temperature stress reducing filler is interposed in each gap between the inner shell oil storage tank and the outer shell caisson 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 figure is installed underwater 10, the bottom part is supported by slightly penetrating the seabed 12, and the upper end partially protrudes above the sea surface 14, and is made of concrete with reinforcing bars placed at appropriate locations. , has the following characteristics.

That is, the oil storage tank has a plurality of convex portions 16, 16, .
It has an outer wall 18 having a generally petal-shaped cross section, and has a double shell structure consisting of an outer shell caisson 20 formed into a bottomed cylinder as a whole, and a cylindrical inner shell oil storage tank 22. There is.

A partition wall 24 is arranged in the axial direction of the outer shell caisson 20, and a plurality of compartments 26, 26... are formed by the partition wall 24 and the outer wall 18, and the overall cross-sectional shape is a honeycomb. It is becoming a state.

The cylindrical inner shell oil storage tanks 22, 22... are arranged in the compartments 26, 26, respectively, and in FIG. A plurality of tank support block mounts 28, 28, . . . project upward and on which the bottom of the oil storage tank 22 is placed,
Buffer members 30, 30, . The other end side has an inner shell oil storage tank 22, inside the compartments 26, 26...
22... is arranged so as to come into contact with its outer surface.

In this case, it is preferable to interpose an elastic material such as rubber on the top surface of the tank support block mount 28 that contacts the bottom and side surfaces of the oil storage tank 22 and on the tip of the buffer member 30.

After arranging the oil storage tanks 22, 22, .
However, in this case, the oil storage tanks 22, 22...
The oil 34 to be stored is sent to each,
Alternatively, inlet/outlet ports for taking this out to the outside are provided at appropriate locations, and an opening for filling with a filler material to be described later is provided in the top plate 32.

On the other hand, after the oil storage tank is installed in the sea 10 and towed to the installation location, the installation location on the seabed 12 is first excavated into a flat shape using an appropriate method, and then water is poured in and submerged, and each of the compartments 26, 26... The gap between the inner shell oil storage tank 22 and the outer shell caisson 20 is filled with a filler material 36 for reducing temperature stress.

This filler 36 may be, for example, sand excavated from the nearby seabed, sand transported by tugboat, or sand mixed with a heat-insulating substance, preferably having a relatively high specific gravity. That's true. The filler material 36 covers the entire outer surface of each inner shell oil storage tank 22, 22... except for the portion where the buffer member 30 supporting the inner shell oil storage tank 22 and the tank support block pedestal 28 are in contact. Fill.

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 the oil 34 is introduced into each tank 22, 22, . . . and stored therein.

Now, in the underwater oil storage tank having the above-mentioned configuration, even if the oil 34 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 20 and the inner shell oil storage tank 22. In addition, since the four circumferences of the inner shell oil storage tanks 22, 22, . The applied temperature stress can be significantly alleviated, and the occurrence of cracks that would cause the tank to lose its function as an oil storage tank can be almost completely eliminated. In addition, an inner shell oil storage tank 2 containing oil 34 is also provided.
2, 22... 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, even when being towed to the installation location or submerged in the sea, the inner shell oil storage tanks 22, 22... are supported by the buffer members 30, 30..., respectively, so that they can be towed or submerged stably. be able to.

Furthermore, the outer wall 18 of the outer shell caisson 20 is
Since the entire structure is curved into an almost cylindrical shape, it can strongly resist underwater waves or currents, and since the cross-sectional shape is honeycomb-like even with the bulkhead 24, the horizontal direction applied to the oil storage tank The structure is extremely strong against external forces.

In the above embodiment, the oil storage tank is installed with its upper end protruding above the sea surface 14, but it goes without saying that it can be installed completely immersed in the sea 10.

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

As described above in detail in the embodiments, in the underwater oil storage tank according to the present invention, the thermal stress applied to the tank side wall can be significantly alleviated, the heat distribution is made uniform, and the towing distance to the installation location is improved. - Enables stable submersion into the sea.

[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...Outer shell caisson, 22...
Inner shell oil storage tank, 24... partition, 26... compartment, 2
8... Tank support block frame, 30... Buffer member, 32... Top plate, 34... Oil, 36... Filler.

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. The outer shell caisson has a double shell structure with a plurality of compartments, and a cylindrical inner shell oil storage tank disposed in each compartment. A buffer member is provided to support the inner shell oil storage tank from the side, and a filler for reducing temperature stress is interposed in each gap between the inner shell oil storage tank and the outer shell caisson in the compartment. An underwater oil storage tank.