JP3596082B2 - Low-temperature storage tank vaporization promotion structure - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a residual liquid vaporization promoting structure in a low-temperature storage tank in which an inner tank is provided inside a outer tank having a predetermined heat-insulating space. Things.
[0002]
[Prior art]
As a low-temperature storage tank for storing a low-temperature liquefied gas such as liquefied natural gas or liquefied propane gas, there is a low-temperature storage tank as shown in FIG. This is because the outer tub 12 is provided on the base slab 11, the inner tub 13 is provided in the outer tub 12 with the heat insulating space (cooling space 14), and the granular heat insulating material is Is filled.
[0003]
The removal of the low-temperature liquid storage from the storage tank is performed via a discharge pipe 15 that penetrates the side plates 12A and 13A of the inner and outer tanks and communicates between the inside and the outside of the storage tank. From the viewpoint, it is restricted to the storage tank side.
[0004]
[Problems to be solved by the invention]
By the way, it is not limited to low-temperature storage tanks, but after storage tanks have been used for a predetermined period of time, it is necessary to perform internal inspection (check the degree of fatigue and repair if necessary) for safety confirmation. At the time of inspection, of course, all the liquid must be taken out and opened.
[0005]
The removal of the liquid from the storage tank is performed through the discharge pipe 15 provided on the side of the storage tank as described above. However, due to the arrangement position of the discharge pipe 15, the residual liquid 16 that cannot be discharged to the bottom of the storage tank is inevitable. These residual liquids 16 are vaporized and taken out. However, since the low-temperature storage tank is configured to keep the inside cool, the internal temperature does not rise, and therefore, the evaporation of the residual liquid is extremely slow. For this reason, heated nitrogen gas or methane gas is sent into the storage tank to promote vaporization.However, a device for that purpose must be temporarily installed, and it is not possible to fill a large capacity storage tank with high-temperature gas. It is not easy, and the heat exchange between the gas and the residual liquid at the liquid level is inefficient, so that the vaporization of the residual liquid cannot be efficiently promoted.
[0006]
As a result, depending on the type of liquid storage and the amount of residual liquid, it takes a long time to evaporate all residual liquid and empty the storage tank, and especially for high boiling liquid storage, several months. This is not uncommon, and during that time, the storage tank cannot be used, so that the operation efficiency of the storage tank deteriorates and the economic loss is extremely large.
[0007]
The present invention has been made in view of the above problems, and promotes the vaporization of a liquid remaining in a storage tank when the storage tank is opened, enables the storage tank to be quickly opened, and prevents deterioration of the operation efficiency of the storage tank. It is an object of the present invention to provide a residual liquid vaporization promoting structure for a low-temperature storage tank that can be used.
[0008]
[Means for Solving the Problems]
The low-temperature storage tank vaporization promoting structure for achieving the above object is a low-temperature storage tank in which an inner tank is provided inside a outer tank having a predetermined heat insulating space, and a linear pipe member having a predetermined length is provided. A heat medium pipe joined with a gap at the seam and formed with the gap as a vent is laid along the bottom surface inside the heat insulating space, and is connected to the heat medium pipe. A supply port protrudes out of the outer tank, and the supply port is connected to a heating medium heating / supplying device provided outside the low-temperature storage tank, and the heating medium heated by the heating medium heating / supplying device is the heating medium. It is characterized in that it is configured to be supplied to the heat-insulated space through a service pipe.
[0011]
[Action]
According to the above construction, by feeding the medium heated by the heat medium heating supply device provided outside the low-temperature storage chamber from the supply port to the heat medium pipe passage, pressurized heated heat medium through the adiabatic space To heat the residual liquid in the storage tank to promote its vaporization. Further, the heat medium pipe can also be used for purging in which air in the heat insulating space is replaced with an inert gas.
[0013]
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
Here, first, a reference example of the present invention will be described.
FIG. 1 is a cross-sectional view of a low-temperature storage tank provided with a reference example of a residual liquid vaporization promoting structure of a low-temperature storage tank according to the present invention.
[0014]
The illustrated low-temperature storage tank 1 is configured 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.
[0015]
The inner tank 30 is provided on a heat-insulating concrete cooling base 40 laid on the upper surface of the foundation slab 10, and between the side plates 31 and the top plate 32 and the side plates 21 and the top plate 22 of the outer tank 20, Cooling spaces 50 are formed at intervals required as heat insulating spaces. Although not shown, the cooling space 50 is filled with a granular heat insulating material.
[0016]
A discharge pipe 60 is provided on the side of the storage tank so as to penetrate the side plates 21 and 31 of the inner and outer tanks 20 and 30 and the cooling space 50 to communicate the inside of the storage tank (inside the inner tank 20) with the outside. Although the end on the inner side of the storage tank is bent toward the inner bottom surface 33, there is a gap between the end and the inner bottom surface 33. Of liquid remains as a non-dischargeable liquid (residual liquid 2 is generated).
[0017]
In the cold insulation base 40, a heating pipe 70 as a heat medium pipe is buried in a portion near (shallow) the surface thereof. The heating pipe 70 goes around the entire area of the cold insulation base 40, and the supply port 71 and the discharge port 72 (only one is shown in the figure) at both ends thereof are arranged outside the outer tank 20. The supply port 71 and the discharge port 72 are provided with valves 73 and 74, respectively, and are normally closed by the valves 73 and 74.
[0018]
Thus, in the low-temperature storage tank 1 having the above-described configuration, the remaining liquid 2 after discharging the stored liquid via the discharge pipe 60 is completely vaporized and opened as described below during internal inspection or the like.
[0019]
That is, the heating medium heating / supplying device 80 was temporarily installed near the storage tank, and the heating medium heating / supplying device 80 was connected to the supply port 71 and the discharge port 72 of the heating tube 70, and the heating was performed by the heating medium heating / supplying device 80. The heating medium is supplied from the supply port 71 into the heating pipe 70, and the heating medium that has passed through the heating pipe 70 and circulated inside the cooling base 40 is recovered from the discharge port 72 and heated and circulated. As a result, the heat medium passing through the heating pipe 70 heats the cold insulating substrate 40, and the cold insulating substrate 40 heats the residual liquid 2 to promote its vaporization. As the heat medium, water (including steam) or an inert gas can be used.
[0020]
In the above-described reference example, the heating pipe 70 is buried in the cooling base 40. However, as shown in FIG. 2, the heating pipe 70 is laid along the inner bottom surface 33 in the inner tank 30. You may. According to this configuration, the construction is simplified as compared with the configuration buried in the cold insulation base 40, and it can be easily additionally installed in an existing storage tank. In the figure, parts having the same functions as those of the above-described reference example are denoted by the same reference numerals.
[0021]
FIG. 3 is a cross-sectional view of a low-temperature storage tank provided with an embodiment of the residual liquid vaporization promoting structure of the low-temperature storage tank according to the present invention. In the drawing, parts having the same functions as those of the above-described reference example are denoted by the same reference numerals. In the illustrated embodiment, a heating tube 90 is disposed below the cool insulation space 40 along the circumferential direction of the cool insulation space 40.
[0022]
As shown in a schematic plan view of the portion in FIG. 4, the heating tube 90 is configured by connecting a linear steel pipe 91 having a predetermined length in a polygonal shape with a gap 92 as a vent at a joint. A supply port 93 communicating with the outside of the storage tank is connected to one of them.
[0023]
In the present configuration, similarly to the above-described reference example, the heating medium heating and supplying device 80 is temporarily provided near the storage tank, and the heating medium heating and supplying device 80 is connected to the supply port 93 of the heating pipe 90. The heat medium heated by the device 80 is supplied from the supply port 93 into the heating tube 90. As a result, the heat medium supplied into the heating pipe 90 is filled and supplied into the cool space 50 through the gap 93, and the inner tank 30 is heated from the outside thereof to promote the vaporization of the residual liquid 2. As the heat medium, a dry inert gas is used because moisture entering the cold storage space 50 is not preferable for later use.
[0024]
In addition, the heating tube 90 of this configuration can also be used when purging air containing oxygen 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]
【The invention's effect】
As described 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 into the heat medium pipe. by feeding pressurized heated heat medium through the adiabatic space heating the residual liquid in the storage tank, to promote the vaporization. For this reason, the residual liquid can be vaporized in a short 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, the heat medium pipe is rational because it can be used for purging in which air in the heat insulating space is replaced with an inert gas.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a low-temperature storage tank provided with a reference example of a residual liquid vaporization promoting structure of a low-temperature storage tank according to the present invention.
FIG. 2 is a cross-sectional view of a low-temperature storage tank provided with another reference example.
FIG. 3 is a cross-sectional view of a low-temperature storage tank provided with one embodiment of the residual liquid vaporization promoting structure of the low-temperature storage tank according to the present invention .
FIG. 4 is a schematic plan view showing the arrangement of the heating tubes.
FIG. 5 is a 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 Insulated space (cooled space)
70 Heating pipe (pipe for heat medium)
71 supply port 72 discharge port 80 heating medium heating / supplying device 90 heating pipe (heating medium pipe)
92 gap (vent)
93 Supply port

Claims (1)

In a low-temperature storage tank in which an inner tank is provided inside the outer tank with a predetermined heat insulating space,
A heat medium pipe formed by joining a linear pipe member of a predetermined length with a gap at a seam and forming the gap as a vent is laid along the bottom surface inside the heat insulating space. In addition, a supply port to the heat medium pipe is protruded outside the outer tank, and the supply port is connected to a heat medium heating / supply device provided outside the low temperature storage tank to supply the heat medium heat. A residual liquid vaporization promoting structure for a low-temperature storage tank, wherein the heat medium heated by the device is supplied to the heat-insulated space through the heat medium pipe.

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