JP5677110B2 - Construction method of cryogenic liquid storage tank - Google Patents

Description

  The present invention relates to a method for constructing a cryogenic liquid storage tank.

  Generally, low-temperature liquids (LNG, LPG, etc.) are stored in an underground or above-ground type low-temperature liquid storage tank having a cold insulation layer on its inner surface. The cryogenic liquid storage tank is configured to have a dome-shaped roof at the upper opening of the bottomed cylindrical tank, and not only the inner surface of the tank but also the inner surface of the roof must be provided with a cold insulation layer. Don't be.

  Patent Document 1 below discloses a construction method for an underground cryogenic liquid storage tank. In this construction method, after the tank body is constructed, the roof portion is assembled at the bottom of the tank body, and a turning scaffold that is turnable in the circumferential direction on the inner surface of the roof portion is attached. The construction period is shortened by installing it in the upper opening of the tank body by the lasing method, and then simultaneously performing the inner surface construction of the tank body and the installation of the cold insulation layer on the inner surface of the roof part using a turning scaffold.

Japanese Patent No. 3213970

  By the way, the cryogenic liquid storage tank is large and has a height of, for example, 50 to 60 meters. Therefore, it is not easy to remove the swiveling scaffold lifted together with the roof portion, and the cryogenic liquid storage tank is permanently installed even when the cryogenic liquid storage tank is delivered. Since the permanent swing scaffold is exposed to a low temperature inside the tank, it uses members (for example, SUS, aluminum, etc.) that are rich in low-temperature brittleness performance to the details. Therefore, it is expensive to construct a turning scaffold that can withstand low temperatures, and improvements in this respect are required.

  This invention is made | formed in view of the said subject, and it aims at provision of the construction method of the cryogenic liquid storage tank which can reduce the cost concerning the turning scaffold for providing a cold insulation layer in the roof part inner surface.

In order to solve the above-described problems, the present invention is a cryogenic liquid storage tank having a dome-shaped roof portion at the upper opening of a bottomed cylindrical tank body, and is swung in the circumferential direction along the inner surface of the roof portion. A method for constructing a cryogenic liquid storage tank in which a cold insulation layer is provided along the inner surface using a free swivel scaffold, the construction step of constructing a rail in the circumferential direction of the inner surface, and the swiveling scaffold from the bottom of the tank body After the suspension is lifted up to the position where the rail is erected using an endless winder, the engaging platform is engaged with the rail so as to be rotatable in the circumferential direction of the inner surface, and the rotating platform is used. Removing the engagement after disposing the cold insulation layer along the inner surface, and suspending the swiveling scaffold from the position where the rail is installed to the bottom of the tank body with an endless winder. Toi To adopt the technique.
By adopting this method, in the present invention, a turning scaffold for installing the cold insulation layer on the inner surface of the roof portion can be temporarily set. In other words, an endless winder is a hoisting machine that unwinds the other end of the rope by the length of the hoist when the one end of the rope is hoisted, and lifts the object indefinitely as long as the length of the rope allows. Can do. For this reason, the restraint of the installation height of the turning scaffold can be eliminated, and the turning scaffold can be removed even after the roof portion is installed at a high place. Accordingly, the turning scaffold can be temporarily set, and the turning scaffold is not made of an expensive and low-temperature brittle material as in the prior art, but a low-temperature room temperature material (ordinary mild steel, general scaffolding material, etc.) is used. It becomes possible.

In the present invention, the above-mentioned turning scaffold employs a technique of having a scaffold frame assembled with a plurality of single pipes.
By adopting this method, in the present invention, the turning scaffold is composed of a hollow single tube pipe, so that it is light and easy to lift / hang, and has high expandability. It can be changed as appropriate. In addition, the dismantling work is easy after the turning scaffold is removed.

In the present invention, the engaging step employs a technique in which the turning scaffold suspended by the endless winder is engaged with a trolley that is slidably engaged along the rail.
By adopting this method, in the present invention, the lifting scaffold is lifted and then engaged with a trolley that can roll along the rail, so that the turning scaffold can be turned along the rail and the roof portion. While installing the cold insulation layer on the inner surface, it is possible to prevent the endless winder from being loaded.

In the present invention, a method is employed in which the endless winder is movably engaged along the rail.
By adopting this method, in the present invention, since the endless winder can move along the rail, the lifting / suspending position of the turning scaffold in the tank can be appropriately changed in the circumferential direction of the inner surface of the roof portion. For this reason, it is possible to lift / hang the turning scaffold at a position where it does not interfere with other operations inside the tank.

Moreover, in this invention, the method of performing the said installation process before installing the said roof part in the upper opening part of the said tank body by an air-raising method is employ | adopted.
By adopting this method, in the present invention, the roof portion is assembled at the bottom of the tank body, the rail is attached to the inner surface of the roof portion in the circumferential direction, and the roof portion is attached to the tank body by an air lasing method. By installing in the upper opening, it is possible to install the rail on the inner surface of the roof without performing the installation work of the rail at a high place.

According to the present invention, in a cryogenic liquid storage tank having a dome-shaped roof portion in an upper opening of a bottomed cylindrical tank body, using a turning scaffold that is turnable in the circumferential direction along the inner surface of the roof portion. A method for constructing a cryogenic liquid storage tank in which a cold insulation layer is provided along the inner surface, and a construction step of constructing a rail in the circumferential direction of the inner surface, and a position where the rail is constructed from the bottom of the tank body. Until it is lifted using an endless winder, and then the step of engaging the turning scaffold with the rail so that it can turn in the circumferential direction of the inner surface, and the cold insulation along the inner surface using the turning scaffold. After providing the layer, the engagement is released, and a removal step of suspending the turning scaffold from the position where the rail is installed to the bottom of the tank body with an endless winder is adopted. I, the turning scaffold for mounting the cold layer to the roof inner surface can be temporary. In other words, an endless winder is a hoisting machine that unwinds the other end of the rope by the length of the hoist when the one end of the rope is hoisted, and lifts the object indefinitely as long as the length of the rope allows. Can do. For this reason, the restraint of the installation height of the turning scaffold can be eliminated, and the turning scaffold can be removed even after the roof portion is installed at a high place. Accordingly, the turning scaffold can be temporarily set, and the turning scaffold is not made of an expensive and low-temperature brittle material as in the prior art, but a low-temperature room temperature material (ordinary mild steel, general scaffolding material, etc.) is used. It becomes possible.
Therefore, in this invention, the expense concerning the turning scaffold for providing a cold insulation layer in a roof part inner surface can be reduced.

It is the schematic which shows the structure of the cryogenic liquid storage tank in embodiment of this invention. It is a figure which shows the structure of the turning scaffold for performing the installation operation | work of the cold insulation layer in the inner surface of the roof part in embodiment of this invention. It is arrow X figure in FIG. FIG. 3 is an arrow Y view in FIG. 2. It is a figure for demonstrating the lifting / suspending operation | work of the turning scaffold in embodiment of this invention.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic diagram showing a configuration of a cryogenic liquid storage tank 1 in an embodiment of the present invention.
The cryogenic liquid storage tank 1 of the present embodiment is an underground LNG storage tank. As shown in the figure, the low-temperature liquid storage tank 1 is provided so as to block the bottomed cylindrical tank body 2 made of concrete constructed by excavating the underground and the upper opening of the tank body 2. It is mainly composed of a dome-shaped roof portion 3. In addition, the corner part between the bottom part of the tank body 2 of this embodiment and a side wall part is provided with the haunch part 2a which relieves stress concentration while improving the rigidity of the tank body 2. FIG.

  The inner surface of the tank body 2 and the roof portion 3 is provided with a cold insulation layer 4 for preventing external heat input. Further, a low temperature liquid (LNG in this embodiment) is applied to the inner surface of the cold insulation layer 4 of the tank body 2. A membrane panel 6 is provided in which corrugations 5 for substantially accommodating and allowing heat shrinkage are formed vertically and horizontally. The cold insulation layer 4 is made of a cold insulation material having excellent heat insulation properties such as PUF (polyurethane foam), for example, and is configured by sequentially arranging a number of divided panels. Similarly, the membrane panel 6 is composed of a plurality of divided metal panels, and a plurality of divided panels are sequentially connected in advance.

  On the inner surface of the dome-shaped roof portion 3, rails 7 </ b> A and 7 </ b> B are installed at a predetermined height in the circumferential direction. The rail 7A is provided on the outer edge of the inner surface of the roof 3 over the entire circumference. The rail 7B is provided over the entire circumference closer to the center portion on the inner side than the rail 7A. The rail 7A and the rail 7B are permanently installed in the low-temperature liquid storage tank 1, and are made of a member rich in low-temperature brittleness performance, for example, I-shaped steel made of SUS material or H-shaped steel. Although not shown, the roof 3 has a cryogenic liquid dispensing pipe for dispensing cryogenic liquid from the inside of the tank, a plurality of inspection doors that can enter the inside from the outside, and access to the inspection door. Inspection ladders, stairs, etc. are provided.

Then, the structure of the turning scaffold 10 for performing the installation work of the cold insulation layer 4 in the roof part 3 inner surface of the said structure is demonstrated with reference to FIGS.
FIG. 2 is a diagram showing a configuration of the turning scaffold 10 for performing the installation work of the cold insulation layer 4 on the inner surface of the roof portion 3 in the embodiment of the present invention. FIG. 3 is an arrow X view in FIG. FIG. 4 is a view on arrow Y in FIG.

  The swiveling scaffold 10 includes a normal soft iron and a general scaffold material that are not members having high low-temperature brittleness performance, and more specifically, a scaffold frame 11 assembled with a plurality of single pipe pipes and a plurality of single pipe scaffold clamps (catch). It consists of As shown in FIG. 2, the turning scaffold 10 includes a plurality of scaffolds 12 a that are stepped along the shape of the inner surface of the dome-shaped roof portion 3. The distance from the scaffold 12a to the inner surface of the roof portion 3 is set such that a worker's hand on the scaffold 12a can reach. In addition, handrails 12 b are erected on both sides of the turning scaffold 10. During work, the scaffold 12a and the handrail 12b are covered with a fall prevention sheet (not shown) to ensure the safety of workers.

  The turning scaffold 10 is configured to engage with the rail 7A and the rail 7B and to turn in the circumferential direction of the inner surface of the roof portion 3. A plurality of trolleys 20 are engaged with the rail 7A and the rail 7B so as to be able to roll along the rails, and the turning scaffold 10 is engaged with the trolley 20 via suspension members such as a suspension shackle and a rope. Match. The trolley 20 includes a gear trolley, and the turning scaffold 10 is moved by appropriately driving the gear trolley.

  In the swing scaffold 10, two engaging portions 13a shown in FIG. 4 are suspended from the rail 7A, and two engaging portions 13b shown in FIG. The engaging portion 13b shown in FIG. 3 is provided with a second engaging portion 13c adjacent to the engaging portion 13b, which is used to attach a rope when the endless winder 21 to be described later is lifted / suspended. is there. The engaging portions 13 b and 13 c are provided on the swing frame 14 that is displaceable about an axis extending in the width direction with respect to the scaffold frame 11.

Subsequently, a construction method for a series of cryogenic liquid storage tanks 1 according to the present embodiment using the turning scaffold 10 having the above-described configuration will be described with reference to FIG.
FIG. 5 is a diagram for explaining the lifting / suspending operation of the turning scaffold 10 according to the embodiment of the present invention.

  First, as shown in FIG. 1, a bottomed cylindrical tank body 2 is constructed by excavating the ground, and roof materials (not shown) such as roof bones and roof plates are carried into the bottom of the tank body 2. The roof part 3 is assembled here. Along with the assembly of the roof part 3, rails 7A and 7B are installed on the inner surface of the roof part 3 (installation process). Next, the roof portion 3 provided with the rails 7A and 7B is raised in the tank body 2 by an air lasing method, and the knuckle plate and the ring plate (not shown) whose outer edge portions are provided in advance in the upper opening of the tank body 2 are provided. By connecting to, the roof portion 3 is installed in the upper opening of the tank body 2. Accordingly, the rails 7A and 7B can be installed on the inner surface of the roof portion 3 without performing the installation work of the rails 7A and 7B at a high place.

  Next, as shown in FIG. 5, ordinary scaffolding materials such as ordinary soft iron and single pipe pipes are carried into the bottom of the tank body 2, and the turning scaffold 10 is constructed at the position indicated by the symbol A (hereinafter referred to as “A position”). To do. In addition, you may carry in the turning scaffold 10 constructed | assembled previously outside the tank body 2 here. In the roof portion 3, a worker who has accessed the rails 7A and 7B from the suspension deck 8 or a construction opening (not shown) attaches a plurality of trolleys 20 (not shown in FIG. 5). As shown in FIGS. 4 and 5, an endless winder 21 for lifting the turning scaffold 10 is attached to the specific trolley 20.

  The endless winder 21 is a hoisting machine that unwinds the other end of the rope by the length of the hoist when the end of the rope is hoisted. The object can be lifted without limit as long as it allows. In this embodiment, since the height at which the rails 7A and 7B are installed is 50 to 60 meters from the bottom of the tank body 2, a rope having a length corresponding to the height is prepared, and the endless winder 21 The rope is hung down to the bottom of the tank body 2.

  An operator at the bottom of the tank body 2 attaches the end of the rope suspended from the endless winder 21 to the turning scaffold 10. In more detail, it attaches to the engaging part 13a or the engaging part 13c of the turning scaffold 10. The attachment position of the rope does not have to be the engaging portion, and may be tied to the scaffold frame 11 body as long as it is a balanced position at the four corners. In this embodiment, since the tank body 2 has the hunch portion 2a, the swing frame 14 of the swiveling scaffold 10 is provided in addition to the rope of the endless winder 21 in order to avoid a collision when the swiveling scaffold 10 is lifted. A second rope is attached at the end of the side.

When the attachment of the rope is completed, the endless winder 21 is driven to lift the turning scaffold 10 from the bottom of the tank body 2 to the position where the rails 7A and 7B are installed. First, the turning scaffold 10 is lifted from the A position to the B position. During this time, by pulling the turning scaffold 10 toward the center of the tank body 2 with the second rope, the collision between the turning scaffold 10 and the tank body 2 is avoided.
Thereafter, only the endless winder 21 on the rail 7B side is driven, and the turning scaffold 10 is inclined at the C position. Next, while maintaining this inclined posture, the turning scaffold 10 is lifted from the C position to the D position and to the E position where the rails 7A and 7B are installed.

When the turning scaffold 10 is lifted to the E position, as shown in FIG. 4, an operator uses the sky gondola 9 or the like to engage the turning scaffold 10 with the trolley 20 via a hanging shackle or rope (engagement step). . Thereby, the turning scaffold 10 can turn freely in the circumferential direction on the inner surface of the roof portion 3, and the endless winder 21 can be prevented from being loaded while the cold insulation layer 4 is installed on the inner surface of the roof portion 3. .
However, the turning scaffold 10 of the present embodiment is light, because it is composed of a hollow single pipe, and is easy to lift / hang, and the load is not so large. Therefore, the turning scaffold 10 is suspended by the endless winder 21 as it is. Until then, the installation work of the cold insulation layer 4 may be performed. According to this, the height adjustment of the turning scaffold 10 can be easily performed.

  Thereafter, installation of the cold insulation layer 4 on the inner surface of the tank body 2 and installation work of the membrane panel 6 are performed, and at the same time, installation work of the cold insulation layer 4 on the inner surface of the roof portion 3 is performed using the turning scaffold 10. On the inner surface of the roof portion 3, an operator gets on the turning scaffold 10 and installs a cold insulation panel on the turning scaffold 10. When the installation of the cold insulation layer 4 in the predetermined range is completed, the turning scaffold 10 is turned using the trolley 20, and the cold insulation layer 4 is installed in the next range. Note that the swiveling scaffold 10 is not a single one but is suspended, and each swiveling scaffold 10 performs the installation work of the cold insulation layer 4 within a pre-allocated range. Incidentally, the other turning scaffold 10 is also lifted in the same manner as described above. For example, as shown in FIG. 4, the endless winder 21 can be moved along the rails 7A and 7B by the trolley 20, so The lifting position can be changed to an appropriate position that does not interfere with other operations.

After all the installation work of the cold insulation layer 4 on the inner surface of the roof 3 is completed, the turning scaffold 10 is then removed (removal process). Specifically, the turning scaffold 10 is suspended by taking the steps opposite to the steps from lifting to engagement described above. In addition, the hanging position of the turning scaffold 10 in the tank is also changed to an appropriate position that does not interfere with other operations.
Specifically, first, the engagement between the rails 7A and 7B and the turning scaffold 10 is released, and the end of the rope fed out from the endless winder 21 is connected to the engaging portion 13a, the engaging portion 13c, or the scaffold frame 11 body. Install.

  When the attachment of the rope is completed, the endless winder 21 is driven to suspend the swiveling scaffold 10 from the position where the rails 7A and 7B are installed to the bottom of the tank body 2. Specifically, as shown in FIG. 5, the turning scaffold 10 is suspended from the E position where the rails 7A and 7B are installed to the D position and the C position. Next, while pulling the turning scaffold 10 toward the center of the tank body 2 with the second rope, only the endless winder 21 on the rail 7B side is driven to change the turning scaffold 10 from the inclined posture to the horizontal posture, and then the haunch. It is hung from the B position to the A position on the bottom of the tank body 2 so as not to collide with the part 2a.

Thereafter, the worker at the bottom of the tank body 2 removes the rope of the endless winder 21 from the turning scaffold 10 at the position A, and disassembles the turning scaffold 10. Since the turning scaffold 10 of this embodiment is comprised from general scaffold materials, such as a single pipe pipe, the dismantling operation | work can be performed easily and rapidly. The disassembled scaffolding materials and the like are carried out of the tank through a manhole or the like. On the roof 3, workers who have accessed the rails 7 </ b> A and 7 </ b> B from the suspension deck 8 or an inspection door (not shown) collect and remove the trolley 20, endless winder 21 and its rope, and carry them out of the tank. Will be.
Thus, the construction of the low-temperature liquid storage tank 1 in the present embodiment is completed.

Therefore, according to the above-described embodiment, in the cryogenic liquid storage tank 1 including the dome-shaped roof portion 3 at the upper opening of the bottomed cylindrical tank body 2, along the inner surface of the roof portion 3 in the circumferential direction. A method of constructing a cryogenic liquid storage tank 1 in which a cold insulation layer 4 is provided along the inner surface using a swivelable swivel scaffold 10, a construction step of constructing rails 7A and 7B in the circumferential direction of the inner surface, and a swivel scaffold 10 Engaging the swiveling scaffold 10 with the rails 7A and 7B so that the swiveling scaffold 10 can be swung freely after being lifted from the bottom of the tank body 2 to the position where the rails 7A and 7B are installed. After the cold insulation layer 4 is provided along the inner surface using 10, the engagement is released, and the turning scaffold 10 is moved from the position where the rails 7 </ b> A and 7 </ b> B are installed to the bottom of the tank body 2 by the endless winder 21. Suspension A step, by employing a technique of having a turning scaffold 10 for mounting the cold layer 4 in the roof section 3 the inner surface can be temporary. In other words, the endless winder 21 is a hoisting machine that unwinds the other end side of the rope when the one end side of the rope is wound up, and lifts the object indefinitely as long as the rope length allows. be able to. For this reason, the restraint of the installation height of the turning scaffold 10 can be eliminated, and the turning scaffold 10 can be removed even after the roof portion 3 is installed at a high place. Therefore, the turning scaffold 10 can be temporarily set, and the turning scaffold 10 is not made of an expensive and low-temperature brittle material as in the past, but a low-temperature normal-temperature material (ordinary mild steel, general scaffolding material, etc.). Can be used.
Therefore, in this embodiment, the cost concerning the turning scaffold 10 for providing the cold insulation layer 4 in the roof part 3 inner surface can be reduced.

  As mentioned above, although preferred embodiment of this invention was described referring drawings, this invention is not limited to the said embodiment. Various shapes, combinations, and the like of the constituent members shown in the above-described embodiments are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

  For example, in the above embodiment, the underground LNG storage tank has been described as an example of the cryogenic liquid storage tank. However, the present invention can also be applied to an underground LPG storage tank that stores LPG, for example. In addition, the present invention can be applied to a ground-type cryogenic liquid storage tank, not an underground type.

  DESCRIPTION OF SYMBOLS 1 ... Low temperature liquid storage tank, 2 ... Tank body, 3 ... Roof part, 4 ... Cold insulation layer, 7A, 7B ... Rail, 10 ... Turning scaffold, 11 ... Scaffold frame, 20 ... Trolley, 21 ... Endless winder

Claims (5)

In a cryogenic liquid storage tank having a dome-shaped roof in the upper opening of a bottomed cylindrical tank body, the cold storage is performed along the inner surface of the roof using a swiveling scaffold that can be swung in the circumferential direction along the inner surface. A method for constructing a cryogenic liquid storage tank in which a layer is provided,
A laying step of laying rails in the circumferential direction of the inner surface;
The suspension scaffold is lifted by using an endless winder from the bottom of the tank body to the position where the rail is installed, and then the pivot scaffold is engaged with the rail so that it can turn in the circumferential direction of the inner surface. Joint process,
After providing the cold insulation layer along the inner surface using the turning scaffold, the engagement is released, and the turning scaffold is suspended from the position where the rail is installed to the bottom of the tank body with an endless winder. A method for constructing a cryogenic liquid storage tank.   The method for constructing a cryogenic liquid storage tank according to claim 1, wherein the turning scaffold has a scaffold frame assembled with a plurality of single pipes.   3. The cryogenic liquid storage tank according to claim 1, wherein, in the engaging step, the swivel scaffold lifted by the endless winder is engaged with a trolley that is slidably engaged along the rail. 4. How to build.   The said endless winder is movably engaged along the said rail, The construction method of the cryogenic liquid storage tank as described in any one of Claims 1-3 characterized by the above-mentioned.   The construction method of the cryogenic liquid storage tank according to any one of claims 1 to 4, wherein the erection step is performed before the roof portion is installed in the upper opening of the tank body by an air lasing method.

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