JPH08261396A - Remaining liquid gasification promoting structure of low temperature storage tank - Google Patents

Abstract

PURPOSE: To provide the remaining liquid gasification promoting structure of a low temperature storage tank wherein during release of a storage tank gasification of storage liquid remaining in the storage tank is promoted, rapid release of the storage tank is practidable, the working efficiency of the storage tank is prevented from worsening. CONSTITUTION: A low temperature storage tank 1 has an outer tank 20 arranged on the upper surface of a foundation slab 10 and an inner tank 30 arranged in the outer tank 20 through a cold insulation space 50. A heating pipe 70 running around the inner side of the tank is buried in the cold insulation foundation 40 of the inner tank 30 and a feed port 71 to the heating pipe 70 and a discharge port 72 from the heating pipe 70 are protruded from the outside of the storage tank 1. Remaining liquid 2 is heated through a cold insulation foundation 40 and gasification thereof is promoted in such a way that a heating medium heated by a heating medium heating feeding device 80 arranged at the outside through the feed port 71 is fed to the heating pipe 70.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a residual liquid vaporization promoting structure in a low temperature storage tank in which an inner tank is internally provided with a predetermined heat insulating space inside an outer tank. It is designed to be done in a short time.

[0002]

2. Description of the Related Art A low temperature storage tank for storing low temperature liquefied gas such as liquefied natural gas or liquefied propane gas is shown in FIG. This is an outer tank 12 on the foundation slab 11.
And the inner tank 13 is provided in the outer tank 12 with a heat insulating space (cooling space 14).
The inside is filled with a granular heat insulating material.

The low temperature liquid is taken out from the storage tank through a discharge pipe 15 which penetrates the side plates 12A and 13A of the inner and outer tanks and connects the inside and the outside of the storage tank.
The arrangement position of 5 is restricted to the side of the storage tank from the viewpoint of facility safety.

[0004]

By the way, the storage tank is not limited to the low temperature storage tank, but the storage tank is subjected to an internal inspection (examine the degree of fatigue and repair if necessary) for safety confirmation after being used for a predetermined period. It is necessary, but of course, in such an internal inspection, all the stored liquid must be taken out and opened.

The liquid is taken out from the storage tank through the discharge pipe 15 provided on the side of the storage tank as described above, but the residual liquid that cannot be discharged to the bottom of the storage tank due to the arrangement position of the discharge pipe 15. 16 inevitably occurs, and these residual liquids 1
There is no other way but to vaporize 6 and take it out. However, since the low temperature storage tank is configured to keep the inside cool, the internal temperature does not rise, and therefore the vaporization of the residual liquid is extremely slow. For this reason, heated nitrogen gas or methane gas is fed into the storage tank in order to promote vaporization.However, a device for that purpose must be installed temporarily, and it is not possible to fill the high-capacity storage tank with hot gas. It is not easy, and since the heat exchange between the gas and the residual liquid on the liquid surface is inefficient, the vaporization of the residual liquid cannot be efficiently promoted.

As a result, it takes a long time to vaporize all the residual liquid and empty the storage tank, depending on the kind of the stored liquid and the amount of the residual liquid, especially in the case of the liquid having a high boiling point. It often takes several months, and the storage tank cannot be used during that period, so the operating efficiency of the storage tank deteriorates and the economic loss is extremely large.

The present invention has been made in view of the above problems, and when the storage tank is opened, the vaporization of the stored liquid remaining in the storage tank is promoted, and the storage tank can be quickly opened to deteriorate the operation efficiency of the storage tank. It is an object of the present invention to provide a structure for promoting vaporization of residual liquid in a low temperature storage tank that can prevent

[0008]

A residual liquid vaporization promoting structure for a low temperature storage tank that achieves the above object is a low temperature storage tank in which an inner tank is internally provided with a predetermined heat insulating space inside the outer tank. A heat medium conduit is embedded in the tank base around the tank, and a supply port to the heat medium conduit and an outlet from the heat medium conduit project outside the outer tank. The supply port is connected to a heat medium heating / supplying device provided outside the low temperature storage tank, and the heat medium heated by the heat medium heating / supplying device is supplied to the heat medium pipe. It is characterized by

Further, in a low temperature storage tank in which an inner tank is internally provided with a predetermined heat insulation space, a heat medium pipe line extends inside the inner tank along the inner bottom surface of the inner tank. And a discharge port from the heat medium pipe and a discharge port from the heat medium pipe are projected outside the outer tank, and the supply port is provided outside the low temperature storage tank. It is characterized in that the heat medium is connected to the heat medium heating and supplying device and the heat medium heated by the heat medium heating and supplying device is supplied to the heat medium pipe line.

Further, in a low temperature storage tank in which an inner tank is internally provided with a predetermined heat insulating space, a heat medium pipe line having a vent is provided inside the heat insulating space along the bottom surface thereof. And a supply port to the heat medium pipe is projected outside the outer tank, and the supply port is connected to a heat medium heating / supplying device provided outside the low temperature storage tank so that the heat The heat medium heated by the medium heating / supplying device is configured to be supplied to the heat insulating space via the heat medium pipe line.

[0011]

According to the above construction, the medium heated by the heat medium heating / supplying device provided outside the low temperature storage tank is fed from the supply port into the heat medium pipe to heat the medium through the heat medium pipe. The generated heat medium heats the residual liquid in the storage tank through the substrate, the heat medium pipe or the heat insulating space, and promotes its vaporization.

Further, in a case where a heat medium pipe line having a ventilation hole is laid inside the heat insulating space, the heat medium pipe line is used when purging the air in the heat insulating space with an inert gas. Can be used for both.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a sectional view of a low temperature storage tank equipped with an embodiment of a structure for promoting vaporization of a residual liquid of a low temperature storage tank according to the present invention.

The low-temperature storage tank 1 shown in the figure is constructed such that an outer tank 20 is provided on the upper surface of the base slab 10 and an inner tank 30 is provided in the outer tank 20.

The inner tank 30 is provided on a heat insulating concrete cold insulation base 40 laid on the upper surface of the foundation slab 10, and between the side plate 31 and the top plate 32 thereof and the side plates 21 and 22 of the outer tank 20. A cold insulation space 50 is formed in the space with a necessary space as a heat insulation space. Although not shown, the heat insulating space 50 is filled with a granular heat insulating material.

On the side of the storage tank, a discharge pipe 60 is provided for the inner and outer tanks 2.
The side plates 21 and 31 of 0 and 30 penetrate the cold storage space 50, and the inside of the storage tank (the inside of the inner tank 20) and the outside are arranged to communicate with each other. The end portion on the inner side of the storage tank is bent toward the inner bottom surface 33 side, but there is a gap between the inner bottom surface 33 and the inner bottom surface 33. Of the stored liquid remains as non-drainable (residual liquid 2 occurs).

A heating pipe 70 as a heat medium pipe line is embedded in the cold insulation base 40 at a portion close to (shallow) the surface thereof. The heating pipe 70 goes around the entire inside of the cold insulation substrate 40, and a supply port 71 and a discharge port 72 (only one of which is shown in the figure) at both ends of the heating pipe 70 are arranged outside the outer tank 20. Supply port 7
Valves 73 and 74 are provided in the 1 and the outlet 72, respectively, and are normally closed by the valves 73 and 74.

In the low temperature storage tank 1 having the above-described structure, the residual liquid 2 after the stored liquid is discharged through the discharge pipe 60 at the time of internal inspection or the like is completely vaporized and opened as follows. To do.

That is, the heat medium heating / supplying device 80 is temporarily installed near the storage tank, and the heat medium heating / supplying device 80 is connected to the supply port 71 and the discharge port 72 of the heating pipe 70. The heated heat medium is supplied from the supply port 71 into the heating pipe 70, and the heat medium that has passed through the heating pipe 70 and passed through the cold insulation substrate 40 is recovered from the discharge port 72 and heated and circulated. As a result, the heat medium passing through the inside of the heating pipe 70 heats the cold insulation substrate 40, and the cold insulation substrate 40 causes the residual liquid 2
Is heated to accelerate its vaporization. Water (including water vapor), an inert gas, or the like can be used as the heat medium.

In the above embodiment, the heating pipe 70 is embedded in the cold insulation base 40, but as shown in FIG. 2, the heating pipe 60 is provided along the inner bottom surface 33 in the inner tank 30. It may be laid. According to this structure, the construction is simpler than the structure buried in the cold insulation base 40, and it can be easily additionally installed in the existing storage tank. In the figure, parts having the same functions as those of the above-described embodiment are designated by the same reference numerals.

FIG. 3 shows another embodiment of the present invention. In the figure, parts having the same functions as those of the above-described embodiment are designated by the same reference numerals. In the illustrated embodiment, a heating pipe 90 is arranged in the lower portion of the cold insulating space 40 along the circumferential direction of the cold insulating space 40.

As shown in the schematic plan view of the heating tube 90 in FIG. 4, a linear steel pipe 91 having a predetermined length is joined in a polygonal shape with a gap 92 serving as a vent hole at the joint. And a supply port 93 communicating with the outside of the storage tank is connected to one of them.

In this configuration, as in the above-described embodiment, the heat medium heating / supplying device 80 is temporarily installed in the vicinity of the storage tank, and the heat medium heating / supplying device 80 and the supply port 93 of the heating pipe 90 are connected to each other. The heat medium heated by the medium heating supply device 80 is supplied into the heating pipe 90 from the supply port 93. As a result, the heat medium supplied into the heating tube 90 is filled and supplied into the cold storage space 50 through the gap 93, and the inner tank 30 is heated from the outside thereof to promote vaporization of the residual liquid 2. As a heat medium,
If moisture enters the cold storage space 50, it is not preferable for later use, so a dry inert gas is used.

The heating tube 90 of this construction can also be used when purging the oxygen-containing air in the cold storage space 50 with nitrogen gas or the like at the start of use of the low temperature storage tank 1.

[0025]

As explained above, according to the residual liquid vaporization promoting structure of the low temperature storage tank according to the present invention, the medium heated by the heat medium heating / supplying device provided outside the low temperature storage tank is supplied from the supply port to the heat medium. By sending it into the pipeline for heat, the heated heat medium passing through the pipeline for heat medium heats the residual liquid in the storage tank through the substrate, the pipeline for heat medium itself or the heat insulation space,
Promote its vaporization. Therefore, the residual liquid can be vaporized in a short period of time, and the storage tank can be quickly opened. As a result, the period required for the internal inspection can be shortened and the operation efficiency of the storage tank can be improved.

Further, in the case where the heat medium pipe line provided with the ventilation hole is laid inside the heat space, the heat medium pipe line is used for purging to replace the air in the heat insulation space with the inert gas. It is rational because it can be used in combination.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a low temperature storage tank having an embodiment of a structure for promoting vaporization of a residual liquid of a low temperature storage tank according to the present invention.

FIG. 2 is a cross-sectional view of a low temperature storage tank having another embodiment.

FIG. 3 is a sectional view of a low temperature storage tank having another embodiment.

FIG. 4 is a schematic plan view showing the arrangement of the heating tubes.

FIG. 5 is a cross-sectional view of a low temperature storage tank as a conventional example.

[Explanation of symbols]

 1 Low-temperature storage tank 20 Outer tank 30 Inner tank 40 Cooling base (base) 50 Insulating space (cooling space) 70 Heating pipe (pipe for heat medium) 71 Supply port 72 Discharge port 80 Heat medium heating and supplying device 90 Heating pipe (heat medium) Pipe line) 92 Gap (vent) 93 Supply port

Claims (3)

[Claims] 1. A low temperature storage tank in which an inner tank is internally provided with a predetermined heat insulation space in an outer tank, and a heat medium pipe line is embedded in the base of the inner tank so as to extend around the inside of the tank. At the same time, a supply port to the heat medium conduit and a discharge port from the heat medium conduit are provided so as to project outside the outer tank, and the supply port is a heat medium heating supply provided outside the low temperature storage tank. A residual liquid vaporization promoting structure for a low temperature storage tank, wherein the heat medium heated by the heat medium heating and supplying device is connected to the device and is supplied to the heat medium pipe. 2. A low temperature storage tank in which an inner tank is internally provided with a predetermined heat insulation space in an outer tank, wherein a heat medium pipe line extends along the inner bottom surface of the inner tank. And a discharge port from the heat medium pipe and a discharge port from the heat medium pipe are projected outside the outer tank, and the supply port is provided outside the low temperature storage tank. A residual liquid vaporization promoting structure for a low-temperature storage tank, which is configured to be connected to a heat medium heating / supplying device and to supply the heat medium heated by the heat medium heating / supplying device to the heat medium pipe line. . 3. A low temperature storage tank comprising an outer tank and an inner tank provided therein with a predetermined heat insulation space, wherein a heat medium pipe having a vent is provided inside the heat insulation space along the bottom surface thereof. And a supply port to the heat medium pipe is projected outside the outer tank, and the supply port is connected to a heat medium heating / supplying device provided outside the low temperature storage tank so that the heat A residual liquid vaporization promoting structure for a low temperature storage tank, characterized in that the heat medium heated by the medium heating and supplying device is configured to be supplied to the adiabatic space via the heat medium pipe.