JP7269832B2 - Cold insulator removal method and cold insulator removal system - Google Patents

Description

TECHNICAL FIELD The present invention relates to a cold insulator removing method and a cold insulator removing system, and more particularly to a cold insulator removing method and a cold insulator removing system for removing powdered cold insulator filled between an inner tank and an outer tank of a low-temperature tank. It is.

2. Description of the Related Art Conventionally, cylindrical double-shell tanks are known as ground-type tanks for storing cryogenic liquids such as liquefied natural gas (hereinafter referred to as “LNG”).

Currently, in such double-shell tanks, a cold insulation space (heat insulation space) between the inner and outer tanks is filled with a cold insulation material (for example, perlite made by firing perlite, hereinafter referred to as “powder perlite”). ) is the mainstream.

By the way, when dismantling a double-shell tank, from the viewpoint of preventing scattering of cold insulation material, etc.,
(a) First, the cooling material is removed from between the inner and outer tanks,
(b) After that, the inner tank and the outer tank are sequentially cut by a fusing device such as a burner and removed.
It is common to do work such as

In recent years, for example, a technique described in Patent Literature 1 has been proposed as a technique for removing such cold insulators.
The technique described in this patent document 1 uses a suction vacuum method,
(a) Suction removal of the cold insulation material on the roof side through a manhole provided on the outer tank roof plate,
(b) After that, the cooling material on the side part side is removed by suction through the manhole provided on the lower side of the outer tank side plate,
It is configured as follows.

According to such a technique, it seems possible to efficiently remove the cold insulating material filled between the inner and outer tanks.

JP-A-10-030347

By the way, in the cold insulation space between the inner tank side plate and the outer tank side plate (hereinafter referred to as "side cold insulation space"), various members (for example, this "side cold insulation space") are provided with so-called perlite diaphragms. In this case, the rod connecting the pearlite diaphragm and the outer tank side plate, the stiffener (reinforcing member) projecting from the inner peripheral surface of the outer tank side plate, hereinafter simply referred to as "various members") are generally provided along the height direction (for example, 40 to 60 m).

In this regard, since the technique of Patent Document 1 removes the cold insulator from the lower side of the outer tank side plate by suction, the cold insulator on "various members" cannot be completely removed, and may remain as it is. It can be said.

That is, in the technique of Patent Document 1, when the outer tank side plate and the inner tank side plate (the side of the double shell tank) are dismantled, a large amount of "powder perlite" remaining on "various members" is released into the atmosphere. There was a problem that the

SUMMARY OF THE INVENTION The present invention has been made to solve such problems, and an object of the present invention is to provide a cold insulating material removing apparatus capable of more reliably removing the powdered cold insulating material filled in the cold insulating space of the low-temperature tank. The object is to provide a method and a cold insulator removal system.

According to the method for removing a cold insulator according to the present invention, an inner tank for storing a low-temperature liquid, an outer tank surrounding the inner tank, and a powdery liquid are provided between the inner tank and the outer tank. and a cold insulation space filled with a cold insulation material, wherein the cold insulation material removal method includes inserting a suction hose into an opening of the outer tank to remove the inner a first cold insulator removing step of sucking and removing the cold insulator existing between the inner tank side plate of the tank and the outer tank side plate of the outer tank; A suction hose is connected to a lower opening opened in the outer tank side plate at a position below the opening according to the accumulation state measured by performing the accumulation state measuring step and the accumulation state measuring step. and a second cold insulating material removing step of inserting and sucking and removing the cold insulating material present below the lower opening.

In addition, according to the cold insulator removal system according to the present invention, the above problem is solved by providing an inner tank for storing a low-temperature liquid, an outer tank surrounding the inner tank, and between the inner tank and the outer tank, A cold insulating material removal system for a low-temperature tank, comprising a cold insulating space filled with a powdered cold insulating material, wherein the cold insulating material removing system is insertable into an opening formed in an outer tank side plate of the outer tank. a suction hose, a suction device for sucking and removing the cold insulating material existing between the inner tank side plate and the outer tank side plate of the inner tank through the suction hose, and the accumulation height of the cold insulating material through the opening. and a measuring device for measuring a deposition state including thickness, wherein the suction hose is opened in the outer tank side plate at a position below the opening according to the deposition state measured by the measuring device. It is also solved by being configured to be insertable into the lower opening.

The term “cryogenic liquid” as used herein means a so-called cryogenic or ultra-low temperature liquid, and includes “LNG”, liquefied petroleum gas (hereinafter referred to as “LPG”), liquefied hydrogen, liquefied oxygen and In addition to ammonia, it is meant to include other fluids (eg, ethylene and liquefied nitrogen).

Further, the above-mentioned "cooling material" may be a powdery member having heat insulation properties, and for example, the above-mentioned "powder perlite" corresponds.

Furthermore, the device ("measuring device") for "measuring the accumulation state including the accumulated height of the cold insulating material" ("measuring device") is any device that can grasp how much the cold insulating material is accumulated through the opening. For example, a laser-type distance sensor capable of measuring a distance by irradiating a laser beam is applicable.

In the configuration according to the present invention,
(a) Insert the suction hose into the opening on the upper side of the outer tank side plate, and remove the cold insulator existing in the "side cold insulation space" (the cold insulation space between the outer tank side plate and the inner tank side plate). , aspirate from top to bottom,
(b) measuring (from above) the state of accumulation of the cold insulator through the opening;
(c) forming a new opening (lower opening) in the outer tank side plate at a position above the accumulation position of the cold insulator;
(d) A suction hose is inserted into the lower opening to suck and remove the cold insulating material existing in the "side cold insulating space" in order from the top.
(e) After that, repeat the above steps (b) to (e),
configured to be able to

That is, in the above configuration, since the cold insulation material in the "side cold insulation space" is sequentially sucked and removed downward, the "various members" provided in the "side cold insulation space" It is possible to sufficiently remove the cold insulation material.

Therefore, in the above configuration, the cold insulating material in the "side cold insulating space" can be almost completely removed, so that the cold insulating material scatters into the atmosphere when dismantling (removing) the inner tank side plate and the outer tank side plate. It is possible to certainly reduce the amount.

In addition, in the invention related to the cold insulating material removing method, the cold insulating material removing method includes a lower opening forming step of forming the lower opening in the outer tank side plate before performing the second cold insulating material removing step. It is preferred to further include.

Further, in the invention related to the cold insulating material removing method, the cold insulating material removing method includes, before performing the second cold insulating material removing step, pulling out the suction hose inserted into the opening and moving it to the lower opening. It is preferable to further include a step of changing the insertion position of the suction hose to be inserted

Furthermore, in the invention related to the cold insulating material removing method, the cold insulating material removing method uses the suction hose to exist below the inner tank bottom plate of the inner tank after performing the second cold insulating material removing step. It is preferable to further include a third cold insulating material removing step of sucking and removing the cold insulating material.
In this case, the cold insulating material removing method includes, before performing the third cold insulating material removing step, a cold insulating material unloading opening for unloading the cold insulating material present below the bottom plate of the inner tank to the outside of the low temperature tank. in each side plate of the outer tank side plate and the inner tank side plate.

As described above, according to the cold insulating material removing method according to the present invention, the powdery cold insulating material filled in the cold insulating space of the low temperature tank can be more reliably removed with a relatively simple configuration. be able to.

1 is a schematic diagram for explaining the outline of a cryogenic tank according to this embodiment; FIG. FIG. 2 is an enlarged cross-sectional view of a main part taken along a dashed line portion II in FIG. 1; FIG. 2 is an enlarged cross-sectional view of a main part taken along a dashed line portion III in FIG. 1; 4 is a sectional view taken along line IV-IV in FIG. 3; FIG. FIG. 2 is a flow chart showing the work flow of the cold insulator removal method according to the present embodiment. FIG. 6 is a flowchart for explaining a side part cold insulator removing step in the cold insulator removing method of FIG. 5 ;

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram for explaining the outline of the cryogenic tank according to the present embodiment, FIG. 2 is an enlarged cross-sectional view of the main part of the broken line portion II in FIG. 1, and FIG. 3 is an enlarged cross-sectional view of the main part of the broken line portion III in FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. 3, FIG. 5 is a flow chart for explaining the work flow of the cold insulator removal method according to the present embodiment, and FIG. 6 is the cold insulator removal method of FIG. is a flow diagram for explaining a side portion cold insulator removing step in .

FIG. 1 shows a cryogenic tank 100 to which a cold insulator removing system 1 (see FIG. 2) according to the present embodiment and a cold insulator removing method using the same are applied. The cold insulator removal system 1, the cold insulator removal method, and the low-temperature tank 100 are respectively described in the claims as the "cold insulator removal system," the "cold insulator removal method," and the "low-temperature tank." ”.

(Configuration of low temperature tank 100)
Here, before describing the cold insulator removing system 1 and the cold insulator removing method, the cryogenic tank 100 according to the present embodiment will be described.
As shown in FIG. 1, the cryogenic tank 100 is an above-ground so-called double-shell tank, which includes an inner tank 110 for storing "LNG", an outer tank 120 provided so as to surround the inner tank 110, A cold insulation space S is formed between the inner tub 110 and the outer tub 120 . In addition, the above-mentioned "LNG", the inner tank 110, the outer tank 120, and the cold insulation space S are respectively the "low temperature liquid", the "inner tank", and the "outer tank" described in the claims. , corresponds to the “cold storage space”.

(Inner tank 110)
As shown in FIGS. 1 to 3, the inner tank 110 is made of a plate-shaped metal member (for example, nickel steel, stainless steel, and aluminum alloy), and includes a circular inner tank bottom plate 111 and a cylindrical inner tank side plate. 112 and a dome-shaped inner tank roof plate 113 . The inner tank bottom plate 111 and the inner tank side plate 112 correspond to the "inner tank bottom plate" and the "inner tank side plate", respectively.

The inner tank bottom plate 111 is placed and fixed on a bottom ring 124 and a plurality of cylindrical blocks 132 which will be described later. In addition, the inner tank side plate 112 is connected to the inner tank bottom plate 111 so as to be erected from the outer peripheral portion, while the inner tank roof plate 113 is connected to the upper end portion of the inner tank side plate 112 with an annular knuckle ring 114 interposed therebetween. It is connected to the.

Here, the knuckle ring 114 will be explained. This knuckle ring 114 is formed from the inner tank side plate 112 and the inner tank roof plate 113 (for example, plate thickness: 10 mm to 15 mm), like a known one (also called a knuckle plate). It is a member (reinforcing member) made of a thick metal member (for example, plate thickness: 30 mm to 50 mm) for reinforcing the outer peripheral portion of the inner tank roof plate 113 where stress tends to concentrate.

(Outer tank 120)
The outer tank 120 is made of a plate-like metal member (for example, carbon steel), and, like the inner tank 110, has a circular outer tank bottom plate 121, a cylindrical outer tank side plate 122, and a dome-shaped outer tank roof. A plate 123 is provided. The outer tank side plate 122 corresponds to the "outer tank side plate" described in the claims.

The outer tank bottom plate 121 is placed and fixed on a foundation B (concrete foundation), and has an annular bottom ring 124 on its upper surface and a plurality of cylindrical blocks spread over the inner peripheral surface of the bottom ring 124. (hereinafter simply referred to as "cylindrical block") 132 are provided.
The bottom ring 124 and the cylindrical block 132 are both made of perlite concrete (perlite mixed with cement, sand, etc.), support the inner tank bottom plate 111 from below, and support the inner tank bottom plate 111 thereon. It is for forming a cold insulation space S (bottom cold insulation space SB described later) between the bottom plate 111 and the outer tank bottom plate 121 .

On the other hand, the outer tank side plate 122 is separated from the inner tank side plate 112 by a predetermined distance so that a cold insulation space S (a side cold insulation space SS, which will be described later) is formed between the outer tank side plate 122 and the inner tank side plate 112. It is connected to the outer peripheral portion of the tank bottom plate 121 .

On the other hand, the outer tank roof plate 123 is connected to the upper end of the outer tank side plate 122, and like the outer tank side plate 122, the inner tank roof plate has a cold insulation space S (roof cold insulation space SU described later). 113 are arranged to face each other.

A plurality of manholes 125 for entering and exiting the cold insulation space S (roof cold insulation space SU described later) are installed at appropriate positions on the outer tank roof plate 123 according to the present embodiment.

(Cooling space S)
The cold insulation space S according to this embodiment includes a bottom cold insulation space SB formed between the inner tank bottom plate 111 and the outer tank bottom plate 121, and a side portion formed between the inner tank side plate 112 and the outer tank side plate 122. It has a cold insulation space SS and a roof cold insulation space SU formed between the inner tank roof plate 113 and the outer tank roof plate 123 .

(Bottom cold insulation space SB)
As shown in FIGS. 1 and 3, the bottom cold insulation space SB includes the bottom ring 124 mounted and fixed on the outer tank bottom plate 121 and a plurality of cylindrical blocks 132, as described above.
In addition, the inside of the cylindrical block 132 and the gaps between the plurality of cylindrical blocks 132 adjacent to each other are filled with powdered perlite 131 . The powdery perlite 131 filled in the bottom cold insulation space SB corresponds to the (powdery) "cold insulation material" present below the "inner tank bottom plate" described in the claims.

(Side cooling space SS)
As shown in FIGS. 1 and 2, in the side cooling space SS,
(a) A pearlite diaphragm 133 is arranged so as to cover the outer peripheral surface of the inner tank side plate 112,
(b) A stiffener 134 (reinforcing member) projecting from an appropriate position on the inner peripheral surface of the outer tank side plate 122 and "various members" such as a rod 135 fixed to the stiffener 134 are provided. In the present embodiment, the case of application to the cryogenic tank 100 provided with the pearlite diaphragm 133 will be described as an example. It can also be applied to

The pearlite diaphragm 133 is made of a plate-like metal member (for example, an aluminum plate with a thickness of 1 mm),
(a) Suspended and fixed via a rod 138 to a steel material (for example, so-called H steel) that supports the outer tank roof plate 123 from below,
(b) It is supported and fixed to the outer tank side plate 122 by bolting the threaded portion of the rod 135 .

As described above, in this embodiment, since the pearlite diaphragm 133 must be supported and fixed to the outer tank side plate 122 or the like, compared to a cryogenic tank (double shell tank) in which the pearlite diaphragm 133 is not provided, The number of supporting hardware (for example, the stiffener 134 and the rod 135) arranged in the side cold insulation space SS is large.

In this embodiment, with this pearlite diaphragm 133 as a boundary,
(a) On the inner tank side plate 112 side, glass wool 136 as a heat insulating material is attached to the outer peripheral surface of the inner tank side plate 112,
(b) the side of the outer tank side plate 122 is filled with powdered perlite 131;
is configured as The powdery perlite 131 (filled in the side cold insulation space SS) is filled (powder-like) between the "inner tank side plate" and the "outer tank side plate" described in the claims. It corresponds to "cooling material".

Here, the reason for providing the glass wool 136 in addition to the powdered perlite 131 in the side cold insulation space SS as described above will be explained. Assuming it was filled
(a) When "LNG" flows into the inner tank 110 (when the inner tank 110 is cooled), the powdery perlite 131 tends to sink due to thermal contraction of the inner tank 110,
(b) In this state, when "LNG" is discharged from the inner tank 110 (when the inner tank 110 is warmed), the powdery perlite 131 that has settled down causes the inner tank 110 to move against the inner tank side plate 112. A force that prevents thermal expansion acts,
This is because, as a result, the inner tank side plate 112 may be damaged.

Therefore, in the present embodiment, with the perlite diaphragm 133 as a boundary, the glass wool 136 is provided on the inner tank side plate 112 side, and the powdered perlite 131 is provided on the outer tank side plate 122 side. , so that thermal contraction and thermal expansion of the inner tank 110 can be tolerated.

In the present embodiment, a pearlite invasion prevention member 137 (for example, a cloth member) is provided above the glass wool 136 to prevent the powdery pearlite 131 from entering the glass wool 136 .

(Roof cold insulation space SU)
The roof cooling space SU is filled with powdered perlite 131 through manholes 125 and the like.

(Configuration of Cold Insulator Removal System 1)
Next, the cold insulator removal system 1 will be described with reference to FIG.
As shown in FIG. 2 , the cold insulator removal system 1 includes a suction device (not shown), a suction hose 10 connected to the suction device, and a distance sensor 20 . The suction device, the suction hose 10, and the distance sensor 20 correspond to the "suction device,""suctionhose," and "measuring device," respectively.

(Suction device)
The suction device is a device that generates a negative pressure for sucking the powdery perlite 131, and can be configured using a known vacuum pump, for example.

(Suction hose 10)
The suction hose 10 is for sucking and removing the powdered perlite 131 present in the cold insulation space S, and can be configured using, for example, a resin bellows hose.

(distance sensor 20)
The distance sensor 20 is a device for measuring the deposition height of the powdered pearlite 131 through openings formed in the outer tank side plate 122 (for example, an upper opening OU and a lower opening OL1, which will be described later).
As such a distance sensor 20, for example, after irradiating a laser beam toward an object to be measured (in this embodiment, powdery perlite 131), based on the time difference until receiving the reflected light, A so-called laser distance sensor that calculates the distance to an object can be used. In the following description, it is assumed that the distance sensor 20 is a laser distance sensor, but other distance sensors can also be used.

Details will be described later, but in this embodiment,
(a) The suction hose 10 is inserted into the upper opening OU formed in the outer tank side plate 122 to suck and remove the powdered perlite 131 existing on the upper side of the side cooling space SS.
(b) After a predetermined amount of powdery perlite 131 is removed by suction, insert the distance sensor 20 into the upper opening OU to measure the deposition height of the powdery perlite 131;
(c) When the measurement result by the distance sensor 20 reaches a predetermined value (for example, the distance from the upper opening OU to the powdered pearlite 131 is "5 m"), the position is slightly higher than the deposition height of the powdered pearlite 131. Form a lower opening OL1 in the outer tank side plate 122 (for example, at a position “1 m” above the deposition position of the powdery pearlite 131),
(d) The suction hose 10 is inserted into the lower opening OL1 to further suck and remove the powdered perlite 131 present in the side cold insulation space SS.
(e) After that, repeat the same work as the above (b) to (d),
As a result, the powdered perlite 131 in the side cold insulation space SS is removed.

(Structure of Cold Insulator Removal Method)
Next, a cold insulator removing method using the cold insulator removing system 1 according to the present embodiment will be described with reference to FIGS. 1 to 6. FIG. In the following,
(a) an external scaffolding TS has already been assembled around the cryotank 100;
(b) After the powdered perlite 131 present in the cold insulation space S (the roof cold insulation space SU, the side cold insulation space SS, and the bottom cold insulation space SB) is removed by suction, the low temperature tank 100 is dismantled;
will be described as a premise.

As shown in FIG. 5, the cold insulator removal method according to the present embodiment includes a roof cold insulator removal step in step S100, a side cold insulator removal step in step S200, and an opening for carrying out the cold insulator in step S300. and a bottom cold insulator removal step in step S400.

(Step S100)
As shown in FIGS. 1, 2, and 5, the method for removing the cold insulator according to the present embodiment starts with performing the step of removing the cold insulator from the roof in step S100.

In the step S100 of removing the cold insulator from the roof, for example,
(a) The suction hose 10 connected to the suction device is inserted into the manhole 125, and the powdery perlite 131 filled in the roof cold insulation space SU is removed by suction as much as possible.
(b) After that, the worker enters the roof cold insulation space SU from the manhole 125 and sucks and removes the remaining powdered perlite 131 with the suction hose 10.
do the work.

In this embodiment, in the step S100 of removing the cold insulation material of the roof, in addition to the powdered perlite 131 in the cold insulation space SU, some of the powdered perlite 131 existing near the upper part of the cold insulation space SS is removed. The suction hose 10 is configured to remove the part by suction.

In this embodiment, after performing the step S100 of removing the cold insulating material from the roof, the step S200 of removing the side cold insulating material, which is the next step, is performed.

(Step S200)
As shown in FIG. 5, in the step S200 of removing the side cold insulating material, the work of removing the powdered perlite 131 in the side cold insulating space SS, specifically, the work of steps S201 to S209 shown in FIG. Do.

(Step S201)
As shown in FIGS. 1, 2 and 6, in the step S200 of removing the side cold insulator, first, in step S201, an upper opening forming step of forming the upper opening OU in the outer tank side plate 122 is performed. start from. The upper opening OU corresponds to the "opening" described in the claims.

Specifically, in this step S201 (upper opening forming step), an upper opening OU into which the suction hose 10 and the distance sensor 20 can be inserted is formed in the vicinity of the upper portion of the outer tank side plate 122 . Such work is performed by a worker using a desired cutting means (for example, a so-called wall saw cutter or a fusing device) from the external scaffolding TS side.
In this embodiment, after the work of step S201 is performed, the work of step S202, which is the next process, is performed.

It should be noted that the size of the upper opening OU should be limited as long as it allows the suction hose 10 and the distance sensor 20 to be inserted at the same time. Smaller is preferred.

(Step S202)
In step S202, the suction hose 10 is inserted into the upper opening OU formed in the outer tank side plate 122 to remove the powdered perlite 131 by suction (upper cold insulator suction step). The work of step S202 corresponds to the "first cold insulating material removing step" recited in the claims.
In this embodiment, after performing the work of step S202, the work of step S203 is performed.

(Step S203)
In the operation of step S203, the distance sensor 20 is inserted into the upper opening OU to measure the accumulation height of the powdered pearlite 131 (upper cold insulator accumulation state measurement step). Incidentally, the operation of step S203 corresponds to the "accumulation state measuring step" described in the claims.
In this embodiment, after the work of step S203 is performed, the work of step S204, which is the next process, is performed.

In the present embodiment, the work of step S203 (upper cold insulator deposition state measuring step) was performed after the work of step S202 (upper cold insulator suction step), but these tasks were performed at the same time, that is, powdered perlite It is also possible to make a configuration to remove this by suction while measuring the pile height of 131 . In addition, in the present embodiment, in the work of step S203, the height of the accumulation of the powdered perlite 131 is measured. can also be configured to check the removal status of

(Step S204)
In step S204, the deposition height of the powdery pearlite 131 measured in the above step S203 (the distance from the upper opening OU to the deposition position of the powdery pearlite 131) is reduced to a predetermined distance (for example, "5 m"). Perform work to confirm whether or not the
In this embodiment, when it is confirmed that the predetermined distance is exceeded as a result of the work in step S204, the work in step S205, which is the next step, is performed, while the predetermined distance is increased. If it is confirmed that the time has not been exceeded, the above steps S202 and S203 are performed again.

(Step S205)
In step S205, a lower opening OL1 into which the suction hose 10 and the distance sensor 20 can be inserted is formed in the outer tank side plate 122 at a position lower than the upper opening OU and higher than the deposition position of the powdered pearlite 131. work (lower opening forming step) is performed. The operation of step S205 and the lower opening OL1 respectively correspond to the "lower opening forming step" and the "lower opening" described in the claims.

Such work can be performed by using a desired cutting tool from the external scaffolding TS side, similarly to the work of step S201 (upper opening forming step).
In this embodiment, after the work of step S205 is performed, the work of step S206, which is the next process, is performed.

(Step S206)
In step S206, the suction hose 10 is inserted into the lower opening OL1 formed in the outer tank side plate 122 (the suction hose inserted in the upper opening OU is 10 is pulled out and inserted into the lower opening OL1), and the work of sucking and removing the powdered pearlite 131 (lower cold insulating material suction step) is performed. The work of inserting the suction hose 10 into the lower opening OL1 and the work of sucking and removing the powdered pearlite 131 through the lower opening OL1 are the "suction hose insertion position changing step" described in the scope of claims. ” and “second cold insulator removing step”.
In this embodiment, after the work of step S206 is performed, the work of step S207, which is the next process, is performed.

In this embodiment, the same suction hose 10 is used as the suction hose 10 inserted into each opening of the upper opening OU and the lower opening OL1. It is also possible to use something else, such as a suction hose 10 for OL1.

(Step S207)
In the work of step S207, the work of inserting the distance sensor 20 into the lower opening OL1 to measure the piled height of the powdery pearlite 131 ( Lower cold insulation material deposition state measurement step) is performed.
In this embodiment, after the work of step S207 is performed, the work of step S208, which is the next process, is performed.

In the present embodiment, the work of step S207 is performed after the work of step S206 (lower cold insulation material suction step), but it is also possible to perform these tasks at the same time. Further, in the operation of step S207, in addition to measuring the deposition height of the powdery pearlite 131, it is also possible to check the removal state of the powdery pearlite 131 using an imaging device.

(Step S208)
In the work of step S208, similarly to the work of step S204, the deposition height of the powdered pearlite 131 measured in the work of step S207 (the distance from the lower opening OL1 to the powdered pearlite 131) is set in advance. An operation is performed to confirm whether or not the distance (for example, "5m") is exceeded.
In this embodiment, when it is confirmed that the predetermined distance is exceeded as a result of the work in step S208, the work in step S209, which is the next process, is performed, while the predetermined distance is increased. If it is confirmed that the time has not been exceeded, the above steps S206 and S207 are performed again.

(Step S209)
In the work of step S209, it is checked whether or not the powdered perlite 131 in the side cold insulation space SS has been removed to the bottom.
In the present embodiment, when it is confirmed that the removal of the powdered perlite 131 in the side cold insulation space SS is not completed, the above steps S205 to S208 are repeated again, while the powdered perlite 131 is removed. When it is confirmed that the removal of the cold insulating material has been completed, step S300 of forming an opening for carrying out the cold insulating material (see FIG. 5) is performed.

Here, the case where it is determined in step S209 that the removal of the powdery perlite 131 in the side cold insulation space SS has not been completed will be described.
For example, when the height of the outer tank side plate 122 of the cryogenic tank 100 is "40 m",
(a) the height at which the upper opening OU is formed is "35 m";
(b) the distance in the height direction between the upper opening OU and the lower opening OL1 is "5 m" (the height at which the lower opening OL1 is formed is "30 m");
(c) the distance that can be sucked by the suction hose 10 through the openings such as the lower opening OL1 (the distance from the openings such as the upper opening OU and the lower opening OL1) is "6 m";
Assuming that the powdered perlite 131 is sucked through the lower opening OL1, the side cold insulation space SS still has a height of "24 m"("35m" - "5 m" - "6 m"). .

In this case, in the present embodiment, the operation of step S205 (lower opening forming step) is performed to form the lower opening OL2 at a height of "25 m", and then steps S206 to S208. Work is performed repeatedly.

In the above example, until the removal of the powdery perlite 131 in the side cold insulation space SS is completed, each position of height "20 m", height "15 m", height "10 m" and height "5 m" , a lower opening is formed.

(Step S300)
As shown in FIGS. 1, 3 and 5, in the process of forming the opening for carrying out the cold insulating material in step S300, workers or transport vehicles are placed inside the lower side of each side plate of the inner tank side plate 112 and the outer tank side plate 122. An operation is performed to form an opening portion OW for carrying out the cold insulating material that can enter and exit the tank 110 . It should be noted that the cold insulating material unloading opening forming step in step S300 and the cold insulating material unloading opening OW are respectively the “cold insulating material unloading opening forming step” and the “cold insulating material unloading opening forming step” described in the scope of claims. It corresponds to the "unloading opening".

The cold insulating material carry-out opening OW is mainly for carrying out the cylindrical block 132 and the like removed by performing the bottom cold insulating material removing step of step S400 to the outside of the low temperature tank 100. FIG. In this embodiment, since the perlite diaphragm 133 is provided in the side cold insulation space SS, the perlite diaphragm in addition to the inner tank side plate 112 and the outer tank side plate 122 is formed in the step S300 of forming the opening for carrying out the cold insulation material. 133 is also configured to have an opening OW for carrying out the cold insulating material.
In this embodiment, after the step S300 of forming the opening for carrying out the cold insulating material is performed, the next step S400 of removing the bottom cold insulating material is performed.

(Step S400)
In the step S400 for removing the cold insulator, the perlite powder 131 and the cylindrical block 132 in the bottom cold insulator space SB are carried out of the low-temperature tank 100 through the opening OW for carrying out the cold insulator. The work of removing the powdered perlite 131 in the bottom cold insulation space SB corresponds to the "third cold insulation material removing step" described in the claims.

Specifically, in the step S400 of removing the bottom cold insulator,
(a) removing the inner tank bottom plate 111;
(b) sucking and removing the powdered perlite 131 in the bottom cold insulation space SB with the suction hose 10;
(c) removing the cylindrical block 132;
etc.

In the present embodiment, the cold insulating material removing process of step S400 is performed to complete the work of the cold insulating material removing method according to the present embodiment.

Thereafter, in this embodiment, the outer tank roof plate 123 and the inner tank roof plate 113 are dismantled (removed), the outer tank side plate 122 and the inner tank side plate 112 are dismantled (removed), and the outer tank bottom plate 121 is dismantled (removed). Work is carried out in this order.

As described above, in this embodiment, after removing the powdery perlite 131 from the roof cold insulation space SU,
(a) forming an upper opening OU on the upper side of the outer tank side plate 122 (upper opening forming step in step S201);
(b) The suction hose 10 is inserted into the upper opening OU to suck and remove the powdery pearlite 131 on the upper side of the side cold insulation space SS (upper cold insulation material suction step in step S202),
(c) inserting the distance sensor 20 into the upper opening OU to measure the deposition height of the powdered pearlite 131 (upper cold insulator deposition state confirmation step in step S203);
(d) On the condition that the deposition height of the powdery pearlite 131 (the distance from the upper opening OU to the deposition position of the powdery pearlite 131) reaches a predetermined value, , forming a lower opening OL1 in the outer tank side plate 122 at the upper position (step S205 for forming a lower opening);
(e) The suction hose 10 is inserted into the lower opening OL1 to suck and remove the powdered perlite 131 in the side cold insulation space SS (lower cold insulation material suction step of step S206);
(f) After that, repeat the same operations as (c) to (e) above,
By performing such a procedure, the powdery perlite 131 in the side cold insulation space SS is removed.

That is, in the present embodiment, since the powdered perlite 131 existing in the side cold insulation space SS is sequentially sucked downward, the "various members" provided in the side cold insulation space SS (eg stiffener 134 and rod 135) can be sufficiently removed.

Therefore, in this embodiment, since the powdery perlite 131 existing in the side cold insulation space SS can be almost completely removed, it scatters into the atmosphere when the outer tank side plate 122 and the inner tank side plate 112 are dismantled (removed). It is possible to reliably reduce the scattering amount of the powdery pearlite 131 .

In this embodiment, the distance in the height direction of the openings formed in the outer tank side plate 122 (for example, the distance in the height direction between the upper opening OU and the lower opening OL1, the distance in the height direction between the upper opening OU and the lower opening OL1 and the lower opening OL2), it becomes possible to further remove the powdered perlite 131 in the side cold insulation space SS.

Further, in this embodiment, after removing the powdery perlite 131 present in the side cold insulation space SS,
(a) Forming cold insulating material unloading openings OW in each side plate of outer tank side plate 122 and inner tank side plate 112 (cold insulating material unloading opening forming step in step S300);
(b) After the inner tank bottom plate 111 is dismantled (removed), the powdery perlite 131 in the bottom cold insulation space SB is removed by suction with the suction hose 10 (bottom cold insulation material removal step in step S400);
(c) Then, the outer tank roof plate 123 and inner tank roof plate 113, the outer tank side plate 122 and inner tank side plate 112, and the outer tank bottom plate 121 are dismantled (removed) in this order.
is configured as

Therefore, in the present embodiment, even when the outer tank bottom plate 121 is dismantled (removed), it is possible to suppress scattering of the powdery perlite 131 into the atmosphere.

In the above embodiment, the upper opening OU is formed on the upper side of the outer tank side plate 122. For example, if an opening (for example, a manhole for inspection) is already provided at a position equivalent to this, If the powdered perlite 131 can be removed by suction using the manhole 125 of the outer tank roof plate 123, this work can be omitted.

Similarly, if the outer tank side plate 122 is provided with openings (e.g., inspection manholes) at predetermined intervals in the height direction, by using these openings, the lower opening OL1 , OL2, etc. can be omitted.

Although the embodiments to which the invention made by the present inventor is applied have been described above, the present invention is not limited by the statements and drawings forming a part of the disclosure of the present invention according to the embodiments. That is, it should be added that other embodiments, examples, operation techniques, etc. made by those skilled in the art based on this embodiment are all included in the scope of the present invention.

1 cold insulator removal system 10 suction hose 20 distance sensor 100 low temperature tank 110 inner tank 111 inner tank bottom plate 112 inner tank side plate 113 inner tank roof plate 114 knuckle ring 120 outer tank 121 outer tank bottom plate 122 outer tank side plate 123 outer tank roof plate 124 Bottom ring 125 Manhole 131 Powdery perlite 132 Cylindrical block 133 Perlite diaphragm 134 Stiffener 135 Rod 136 Glass wool 137 Pearlite entry prevention member 138 Rod B Foundation S Cold insulation space SB Bottom cold insulation space SS Side cold insulation space SU Roof cold insulation space OU Top opening OL1, OL2 Lower opening OW Opening for carrying out cold insulation material TS External scaffolding

Claims (6)

an inner tank for storing a cryogenic liquid;
an outer tank surrounding the inner tank;
a cold insulating space provided between the inner tank and the outer tank and filled with a powdered cold insulating material;
A cold insulator removal method for a cryogenic tank comprising
The cooling material removing method includes:
A first cold insulating material removing step of inserting a suction hose into an opening formed in the outer tank and sucking and removing the cold insulating material present between the inner tank side plate of the inner tank and the outer tank side plate of the outer tank. and,
a deposition state measuring step of measuring a deposition state including a deposition height of the cold insulator through the opening;
A suction hose is inserted into a lower opening opened in the outer tank side plate at a position below the opening according to the accumulation state measured by performing the accumulation state measuring step, and a suction hose is inserted from the lower opening. a second cold insulating material removing step of sucking and removing the cold insulating material that is also present below;
including,
A cold insulator removing method characterized by: The cooling material removing method includes:
Further comprising a lower opening forming step of forming the lower opening in the outer tank side plate before performing the second cold insulating material removing step.
2. The cold insulator removal method according to claim 1, characterized in that: The cooling material removing method includes:
Further comprising a suction hose insertion position changing step of pulling out the suction hose inserted in the opening and inserting it into the lower opening before performing the second cold insulation material removing step,
3. The cold insulating material removing method according to claim 1 or 2, characterized in that: The cooling material removing method includes:
After performing the second cold insulating material removing step, a third cold insulating material removing step of sucking and removing the cold insulating material existing below the inner tank bottom plate of the inner tank using the suction hose is further included.
The cold insulator removing method according to any one of claims 1 to 3, characterized in that: The cooling material removing method includes:
Before performing the third cold insulating material removing step, the cold insulating material unloading opening is formed in the outer tank side plate and the inner tank side plate in order to carry out the cold insulating material existing below the inner tank bottom plate to the outside of the low temperature tank. Further comprising a step of forming an opening for carrying out the cold insulating material formed in each side plate of
5. The cold insulator removing method according to claim 4, characterized in that: an inner tank for storing a cryogenic liquid;
an outer tank surrounding the inner tank;
a cold insulating space provided between the inner tank and the outer tank and filled with a powdered cold insulating material;
A cryogenic tank cold insulation removal system comprising:
The cooling material removal system includes:
a suction hose that can be inserted into an opening formed in an outer tank side plate of the outer tank;
a suction device for sucking and removing the cold insulating material existing between the inner tank side plate and the outer tank side plate of the inner tank via the suction hose;
a measuring device for measuring a piled state including a piled height of the cold insulator through the opening;
with
The suction hose is
configured to be insertable into a lower opening opened in the outer tank side plate at a position below the opening according to the deposition state measured by the measuring device;
A cold insulator removal system characterized by:

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