JP2010280436A - Method of constructing ceiling part of water sealed gas holder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To apply a corrosion-proofing paint to a portion of a steel plate for a ceiling plate of a water sealed gas holder where the corrosion-proofing paint could not be applied conventionally. <P>SOLUTION: A method of constructing the ceiling of the water-sealed gas holder includes welding steel plates M for the ceiling plate which are laid on ceiling frames 30 after the ceiling frames 30 are assembled, and applying a corrosion-proofing paint P to the back surface of the ceiling which is the inner surface of the steel plates M for the ceiling plate. The method includes laying the steel plates M for the ceiling plate on the ceiling frames 30 via spacer bolts 42, welding the steel plates M for the ceiling plate and the ceiling frames 30 so as to secure a gap S therebetween, and applying the corrosion-proofing paint P onto the back surface of the steel plates M for the ceiling plate after the welding. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for constructing a ceiling portion of a water-containing gas holder.

  In order to use by-product gases such as blast furnace gas (BFG), coke oven gas (COG), converter gas (LDG), etc. generated from the steel plant as fuel, the by-product gas is temporarily stored. The water-based gas holder is installed. As shown in FIG. 13, the water-containing gas holder 100 includes an outer tank 103, a middle tank 104, and an inner tank that are a plurality of telescope-type gas tanks that are movable up and down inside a water tank 102 that stores water 101. 105, and has a structure in which a water sealing portion by a cup 106 and a sealing plate 107 is provided between adjacent gas tanks. When the gas storage amount increases, each gas tank rises as the pressure in the gas tank increases, and when the gas storage amount decreases, each gas tank descends as the pressure inside the gas tank decreases. .

  Generally, such a water-containing gas holder is formed by joining a plurality of steel plates by welding. As shown in FIG. 14, the ceiling 105 a of the inner tub 105 is laid on the ceiling framework 120 formed in an arch shape so that the steel plates 121 for the ceiling plate overlap each other, and the overlapping portions are formed from the outer surface. It is formed by welding. Thereby, when the pressure in the inner tank 105 rises, as shown by a broken line in FIG. 14, the entire ceiling 105a is bent.

  Incidentally, the by-product gas generated from the ironworks contains corrosive components such as CO2 gas and saturated water vapor. Therefore, the inside of the water-containing gas holder becomes a corrosive environment due to the water 101 in which a corrosive component such as CO2 is dissolved in the condensed water generated by condensation of the by-product gas and the saturated water vapor in the by-product gas. Therefore, in a storage tank for storing such a by-product gas, it is usual that an anticorrosion coating for preventing corrosion is applied to the inner surface (for example, Patent Document 1).

JP 2003-26285 A

  In performing the anticorrosion coating as described above, a method is generally used in which a steel plate that has been subjected to an anticorrosion coating in advance is used, and a portion where the anticorrosion coating is peeled off by the heat of welding is repaired after welding. However, since the ceiling plate steel plate 121 constituting the ceiling 105a of the water-containing gas holder is welded in a state of being laid on the ceiling frame 120, when repairing a portion where the anticorrosion coating has been peeled off due to the heat of welding. The portion in contact with the ceiling framework 120 on the back surface of the ceiling plate steel plate 121 could not be repaired with anticorrosion coating.

  For this reason, as shown by the broken line in FIG. 14, when the ceiling 105a is lifted, the steel plate 121 for the ceiling plate where the anticorrosion coating is peeled is exposed to the corrosive environment, and the corrosion of the portion where the anticorrosion coating is peeled off proceeds. Eventually, there was a problem that the by-product gas inside leaked outside due to opening.

  As a means for preventing the corrosion of the steel plate 121 for the ceiling plate, it is conceivable to use a corrosion-resistant steel plate such as stainless steel, for example, but the water-containing gas holder is generally a huge structure with a diameter of several tens of meters. In addition, if the entire surface of the ceiling 105a is made of a corrosion-resistant steel plate, it becomes very expensive, so it cannot be said that it is a realistic measure from the viewpoint of cost.

  The present invention has been made in view of the above points, and a water-containing gas holder is provided by applying an anti-corrosion coating to a portion of a steel plate for a ceiling plate of a water-containing gas holder that could not be conventionally subjected to the anti-corrosion coating. The purpose is to extend the service life.

  In order to achieve the above object, the present invention achieves the above-mentioned object by coating and welding a ceiling plate steel plate on the ceiling framework after assembling the steel ceiling framework, and anticorrosion coating the ceiling back surface, which is the inner surface of the ceiling plate steel plate. In the method of constructing the ceiling portion of the water-containing gas holder, a ceiling plate steel plate is laid on the ceiling frame via a spacer, and a clearance is secured between the ceiling frame and the ceiling plate steel plate. The anti-corrosion coating on the back of the ceiling is applied after welding.

  According to the present invention, since welding is performed in a state in which a gap is secured between the ceiling plate steel plate and the ceiling frame by the spacer, the steel plate welding for the ceiling plate that could not be repaired conventionally because it is in contact with the ceiling frame. Repair coating can be applied to the back surface of the part from the gap. Thereby, the opening resulting from exposure of the ceiling of the water-containing gas holder to a corrosive environment can be prevented, and the life of the water-containing gas holder can be extended.

  The spacer may be a spacer bolt provided through a bolt hole formed in the ceiling frame, or may be a refractory material or a heat insulating material placed on the ceiling frame.

  The spacer bolt may be removed after the anti-corrosion coating on the back surface of the ceiling, and the anti-corrosion coating may be applied to the inner surface of the bolt hole and the contact portion of the spacer bolt after the spacer bolt is removed.

  The ceiling frame may be pre-painted before assembling, and the steel sheet for ceiling plate may be pre-coated with anticorrosion before being laid on the ceiling frame.

  In addition, the anti-corrosion coating previously given to the said steel plate for ceiling boards may be given to the part except a welding heat influence part.

  ADVANTAGE OF THE INVENTION According to this invention, it is possible to prolong the life of the water-containing gas holder by applying the anti-corrosion coating to the portion of the steel plate for the ceiling plate of the water-containing gas holder that could not be conventionally subjected to the anti-corrosion coating. .

It is a longitudinal cross-sectional view which shows the outline of a structure of the water-containing gas holder concerning this Embodiment. It is a longitudinal cross-sectional view which shows the outline of a structure of the ceiling vicinity of the water-containing gas holder concerning this Embodiment. It is a top view which shows the outline of a structure of the ceiling vicinity of the water-containing gas holder concerning this Embodiment. It is a flowchart of the preparation process concerning this Embodiment, and an installation process. It is explanatory drawing which shows the state by which the nut was attached to the ceiling frame. It is explanatory drawing which shows the state by which anti-corrosion coating was given to the ceiling frame. It is explanatory drawing which shows the state in which the spacer bolt was attached to the ceiling frame. It is explanatory drawing which shows the state by which the steel plate for ceiling boards was laid out on the spacer bolt. It is explanatory drawing which shows the state which gave anti-corrosion coating after the welding of the steel plate for ceiling boards. It is explanatory drawing which shows the state which extracted the spacer bolt from the frame for ceilings, and landed the ceiling board on the ceiling frame. It is explanatory drawing which shows the state which gave anticorrosion coating after landing of a ceiling board. It is explanatory drawing which shows the structure of the ceiling frame vicinity at the time of using a firebrick as a spacer. It is a longitudinal cross-sectional view which shows the outline of a structure of the conventional water-containing gas holder. It is a longitudinal cross-sectional view which shows the structure of the ceiling vicinity of the conventional water-containing gas holder.

  Embodiments of the present invention will be described below. FIG. 1 is a longitudinal sectional view showing an outline of a configuration of a water-containing gas holder 1 according to the present embodiment.

  The water-containing gas holder 1 includes a water tank 10 for storing water 2, an outer tank 11, a middle tank 12 and an inner tank 13, which are a plurality of gas tanks that can be moved up and down inside the water tank 10, and the periphery of the water tank 10. And a plurality of base pillars 14 that are arranged perpendicularly to guide the ascending and descending operations of the outer tub 11, the middle tub 12, and the inner tub 13.

  The water tank 10 is a tank that is disposed at the bottom of the water-containing gas holder 1 and stores water therein, and this water serves as a gas seal. The water tank 10 has a substantially circular bottom surface and is formed in a substantially cylindrical shape without a lid. Further, in the water tank 10, for example, a gas pipe (not shown) for supplying the by-product gas from the converter into the gas tank and discharging the by-product gas to the customer is provided through the bottom surface. The water tank 10 extends to the surface of the water.

  The outer tub 11 is inserted into the water tub 10, the middle tub 12 is inserted into the outer tub 11, the inner tub 13 is inserted into the middle tub 12, and is provided so as to be movable up and down. The outer tank 11 and the middle tank 12 are formed in, for example, a substantially cylindrical shape having no bottom surface and no lid. The inner tank 13 has a ceiling 15 and is formed in a substantially cylindrical shape having no bottom.

  In order to prevent the inner surfaces of the water tank 10, the outer tank 11, the middle tank 12 and the inner tank 13 from corroding each tank with water 2 in which the corrosive component in the by-product gas and the corrosive component in the by-product gas are dissolved. Anticorrosion coating (not shown) is applied.

  Between the adjacent outer tank 11 and intermediate tank 12 and between the intermediate tank 12 and the inner tank 13, water sealing portions 22 are provided by a lower cup sealing water plate 20 and an upper cup sealing water plate 21, respectively. The lower cup sealing water plate 20 is provided at the lower end portions of the outer peripheral surfaces of the middle tank 12 and the inner tank 13, and has a substantially U-shaped cross-sectional shape opened upward. The upper cup sealing plate 21 is provided at the upper end portions of the inner peripheral surfaces of the outer tub 11 and the middle tub 12, and has a substantially U-shaped cross-sectional shape that is open at the bottom, contrary to the lower cup sealing plate 20. ing. For this reason, the lower cup sealing water plate 20 and the upper cup sealing water plate 21 having the opposing substantially U-shaped shapes can be engaged with each other. Therefore, when the gas storage amount in the water-containing gas holder 1 is increased and the internal pressure of the water-containing gas holder 1 is increased, the rising force of the inner tank 13 is transmitted to the middle tank 12, and the rising force of the middle tank 12 is It is transmitted to the outer tub 11. Thereby, the inner tank 13 can pull the middle tank 12 and the outer tank 12 upward, and can raise the middle tank 12 and the outer tank 11 as shown in FIG.

  In each lower cup sealing plate 20, water 2 is stored while seated in the water tank 10, and when the middle tank 12 and the inner tank 13 rise, each upper cup sealing plate 21 is It is inserted below the water surface of the water 2 in the lower cup sealing water plate 20. Thereby, it has the structure where the gas inside the inner tank 12 and the inner tank 13 does not leak out of the tank. The outer tub 11 can prevent leakage of by-product gas from the inside of the outer tub 11 to the outside of the tub when the lower end of the outer tub 11 is immersed below the water surface of the water 3 of the water tub 10.

  For example, a plurality of base pillars 14 are arranged at regular intervals around the water tank 10. In FIG. 1, for convenience of illustration, only two base pillars 14 arranged symmetrically with respect to the center of the water tank 10 are schematically shown. The base column 14 is in contact with the upper guide roller 25 provided at the uppermost edge of the outer tank 11 and the middle tank 12 and the outermost edge of the inner tank 13 on the ceiling 15, and guides when each gas tank is raised and lowered. Take a role.

  Next, the structure of the inner tank 13 will be described. FIG. 2 is a longitudinal sectional view showing an outline of the configuration in the vicinity of the ceiling 15 of the inner tank 13. The ceiling 15 is configured by an upwardly projecting arch-shaped ceiling frame 30 provided on the side plate 13 a of the inner tank 13 and a ceiling plate 31 provided on the ceiling frame 30. The ceiling frame 30 is, for example, an H-shaped steel.

  As shown in FIG. 3, the ceiling plate 31 is formed of, for example, a plurality of fan-shaped steel plates for ceiling boards M, which are laid on top of each other with their ends overlapped with each other. It is formed by joining the end portion and the upper surface of the steel plate M for ceiling plate that overlaps the bottom portion by fillet welding. Anti-corrosion coating (not shown) is applied to the entire surface of the ceiling frame 30 and the ceiling plate 31.

  Next, a procedure for forming the ceiling 15 configured as described above will be described. FIG. 4 shows a flowchart of the preparation process A and the installation process B. The work is roughly divided into a preparation process A performed before the ceiling frame 30 is mounted and an installation process B until the anticorrosion coating P is performed after the ceiling frame 30 is mounted.

  In the preparation step A, a plurality of bolt holes 40 are formed at predetermined positions on the side of the ceiling framework 30 on which the ceiling plate steel plates M are laid out before the ceiling framework 30 is overlaid on the side plate 13 a of the inner tub 13. A nut 41 is attached to the surface corresponding to the bolt hole 40 on the opposite side to the surface on which the ceiling plate steel plates M are arranged (A1 in FIG. 4 and FIG. 5).

  Next, the anticorrosion coating P is applied to the entire surface of the ceiling frame 30 to which the nut 41 is attached (A2 in FIG. 4 and FIG. 6). At this time, even if the anticorrosion coating P is applied to the inner surface of the bolt hole 40 and the inner surface of the nut 41, the anticorrosion coating P is peeled off by contact with the spacer bolt 42 described later. P is not applied.

  After the anti-corrosion coating P is applied to the ceiling frame 30, the tip 42a of the spacer bolt 42 is attached through the nut 41 so as to pass through the bolt hole 40 and protrude from the upper surface of the ceiling frame 30 (A3 and FIG. 4). FIG. 7). The spacer bolt 42 can be adjusted by the nut 41 so that the portion protruding from the upper surface of the ceiling frame 30, that is, the height of the tip 42 a can be adjusted. The height at which the spacer bolt 42 protrudes from the upper surface of the ceiling frame 30 is After the ceiling plate 31 described later is welded, it is adjusted so as to ensure a predetermined gap S in which the anticorrosion coating P can be applied between the ceiling frame 30 and the ceiling plate 31.

  The ceiling frame 30 to which the anticorrosion coating P is applied and the spacer bolts 42 are attached is overlaid on the side plate 13a of the inner tank 13 and assembled in an arch shape (B1 in FIG. 4). Next, the ceiling plate steel plate M is laid on the tip 42a of the spacer bolt 42 protruding from the upper surface of the ceiling frame 30 such that the ends thereof overlap each other (B2 in FIG. 4 and FIG. 8). At this time, the spacer bolt 42 functions as a spacer that forms a predetermined gap S between the ceiling framework 30 and the ceiling plate steel plate M. Further, the place where the spacer bolt 42 is attached to the ceiling frame 30, that is, the place where the bolt hole 40 is formed in the ceiling frame 30 is the ceiling plate steel plate M placed on the tip 42 a of the spacer bolt 42. It is set so that the welding work of the steel plate M for plates can be performed. In FIG. 8, for the convenience of illustration, the steel sheet M for the ceiling plate that has not been subjected to the anti-corrosion coating P is laid out. However, the surface of the ceiling plate steel plate M that is in contact with the by-product gas is previously applied with the anti-corrosion coating P. It is preferable to keep it. This is because by performing the anticorrosion coating P in advance, the work at a high place after the ceiling frame 30 is mounted is reduced.

  The ceiling plate steel plates M laid on the spacer bolts 42 are joined by fillet welding between the end portions of the ceiling plate steel plates M and the upper surfaces of the ceiling plate steel plates M that overlap therewith. Is formed (B3 in FIG. 4). In addition, about the steel plate M for ceiling plates, even if the anti-corrosion coating P is given previously in the vicinity of the fillet welding part 43 joined by fillet welding, the anti-corrosion coating P will peel off by the heat effect of welding. Therefore, even when the anticorrosion coating P is applied to the ceiling plate steel plate M in advance, it is not necessary to apply the anticorrosion coating P in the vicinity of the fillet weld 43 of the ceiling plate steel plate M in advance.

  After the welding operation is completed, the anticorrosion coating P is applied to the ceiling plate steel plate M using the gap S and dried (B4 in FIG. 4 and FIG. 9). After the anticorrosion coating P is completely dried, the spacer bolts 42 are sequentially removed from the nut 41, and the integrally formed ceiling plate 31 is landed on the ceiling framework 30 (B5 in FIG. 4 and FIG. 10).

  Thereafter, the anticorrosion coating P is also applied to the inner surface of the bolt hole 40 and the inner surface of the nut 41 after the spacer bolt 42 is removed. At this time, the upper end 42a of the spacer bolt 42 and the steel plate M for the ceiling plate were in contact with each other, so that the anticorrosion coating P could not be applied, or the anticorrosion coating previously applied by contacting the spacer bolt 42. The anticorrosion coating P is also applied to the place where P is damaged (B6 in FIG. 4 and FIG. 11). Thereby, anticorrosion coating P is given to the whole surface of the side in contact with the by-product gas of the ceiling board 31.

  The water-containing gas holder 1 according to the present embodiment is configured as described above. Next, the operation of the water-containing gas holder 1 will be described.

  First, when by-product gas flows into the water-containing gas holder 1 from the gas pipe, the gas pressure in the inner tank 13 increases. Accordingly, the inner tub 13 rises and the entire ceiling plate 31 bends upward, and the portion of the ceiling plate 31 that has landed on the ceiling framework 30 is exposed to by-product gas. At this time, since the ceiling plate 31 is provided with the anticorrosion coating P over the entire surface in contact with the by-product gas, the operation can be performed without exposing the base material surface of the steel plate M for the ceiling plate to a corrosive environment. Is possible.

  And each gas tank of the water-containing gas holder 1 repeats raising / lowering operation | movement according to the quantity of by-product gas to store.

  According to the above-described embodiment, the ceiling plate steel plate M is secured in a state where the predetermined gap S that allows the work of the anticorrosion coating P is secured between the ceiling plate steel plate M and the ceiling framework 30 by the spacer bolts 42. Since the welding is performed, the anticorrosion coating P can be applied from the gap S to the back surface of the steel plate M welded portion for the ceiling plate, which conventionally cannot be applied because it is in contact with the ceiling framework. Thereby, it is possible to prevent the ceiling 15 of the water-containing gas holder from being opened by being exposed to a corrosive environment, and to extend the life of the water-containing gas holder 1. In addition, by providing the clearance S with the spacer bolt 42, the ceiling frame 30 that has been affected by the heat of welding in the past by contacting the welded portion of the steel plate M for ceiling plate greatly reduces the influence of the heat of welding. Therefore, the anticorrosion coating P of the ceiling frame 30 is not damaged, and it is possible to prevent the ceiling frame 30 from being corroded. Further, the mechanical strength of the ceiling frame 30 due to the influence of welding heat can be reduced.

  In the above embodiment, the portion other than the welded portion of the ceiling plate steel plate M and the ceiling framework 30 have been subjected to the anticorrosion coating P in advance, but the anticorrosion coating P does not necessarily have to be applied in advance. The anticorrosion coating P may be applied after the frame is overlaid. Further, the anticorrosion coating P may be applied to the welded portion of the steel plate M for the ceiling plate in advance, and the anticorrosion coating P may be applied as a repair coating to the portion where the anticorrosion coating P is peeled off by heat after welding. The range to which P is applied is determined arbitrarily by comprehensively judging the safety and cost of work.

  In the above embodiment, since the bolt holes 40 are provided in the ceiling frame 30, it is conceivable that the strength of the ceiling frame 30 is reduced. In that case, necessary reinforcement is appropriately performed at a location where the strength is insufficient.

  Further, in the above embodiment, the spacer bolt 42 is removed after welding the ceiling plate steel plate M. However, before the welding, the entire surface of the lower surface of the ceiling plate steel plate M is subjected to the anticorrosion coating P in advance. 40 is provided so as to support the location where the spacer bolt 42 is not affected by the heat of welding the ceiling plate steel plate M, that is, the location where the anticorrosion coating P does not need to be applied after welding, the anticorrosion coating after welding. Since P should be applied only to the heat affected zone of welding, it is not always necessary to remove the spacer bolt 42. In the case where the spacer bolt 42 is not removed, it is possible to reduce the steps for the anticorrosion coating P on the ceiling plate 31.

  In the case where the spacer bolt 42 is not removed, in order to prevent the spacer bolt 42 from being corroded, the nut 41 and the spacer bolt 42 are attached to the ceiling frame 30 and the nut 41 and the spacer bolt 42 are protected against the ceiling frame 30 together. It is preferable to apply the coating P.

  In addition, when the spacer bolt 42 is provided in a place where it is not necessary to remove the spacer bolt 42, the spacer bolt 42 need not necessarily be the spacer bolt 42, and can support the load when the ceiling board 31 is landed on the spacer. Any selection is possible. In this case, when the heat at the time of welding is transferred to the spacer, a material that does not decrease in strength due to heat and does not corrode in the atmosphere in the water-containing gas holder 1 without applying the anticorrosion coating P is preferable. Use of heat insulating materials such as refractory bricks and calcium silicate can be proposed. When using refractory bricks or the like, for example, as shown in FIG. 12, the refractory bricks 51 are fixed by the studs 50 fixed to the upper surface of the ceiling framework 30 by welding or the like, and the anticorrosion coating P is applied together with the ceiling framework 30. It may be. By doing in this way, the process of the bolt frame 40 and the reinforcement of the ceiling frame 30 which were required when using the spacer bolt 42 become unnecessary, and the processing cost of the ceiling frame 30 can be reduced. In addition, when not removing a spacer from the ceiling frame 30, in order to prevent that the anticorrosion coating P peels off when the steel plate M for ceiling plates and the said spacer contact, the contact part of the steel plate M for ceiling plates and the said spacer It is preferable to apply the anticorrosion coating P thicker than other portions.

  The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious for those skilled in the art that various modifications or modifications can be conceived within the scope of the idea described in the claims, and these naturally belong to the technical scope of the present invention. It is understood.

  The present invention is useful when constructing a ceiling plate of a water-containing gas holder.

DESCRIPTION OF SYMBOLS 1 Water-containing gas holder 2 Water 10 Water tank 11 Outer tank 12 Middle tank 13 Inner tank 13a Side plate 14 Base pillar 15 Ceiling 20 Lower cup sealing plate 21 Upper cup sealing plate 22 Water sealing portion 25 Upper guide roller 30 Ceiling frame 31 Ceiling Plate 40 Bolt hole 41 Nut 42 Spacer bolt 42a Tip 43 Fillet weld 50 Stud 51 Refractory brick M Steel plate for ceiling plate P Anticorrosion coating S Gap

Claims (7)

In the construction method of the ceiling portion of the water-containing gas holder, after assembling the steel ceiling frame, the ceiling plate steel plate is laid and welded on the ceiling frame and welded, and the ceiling back surface, which is the inner surface of the ceiling plate steel plate, is anticorrosive coated. ,
Laying the steel plate for the ceiling plate on the ceiling frame via a spacer,
Secure and weld a gap between the ceiling framework and the steel plate for ceiling plate,
The construction method of the ceiling part of a water-containing gas holder characterized by performing the anti-corrosion coating of the back surface of the steel plate for ceiling plates after welding. The construction method for the ceiling portion of the water-containing gas holder according to claim 1, wherein the spacer is a spacer bolt provided by inserting a bolt hole formed in the ceiling frame. The spacer bolt is removed after the anti-corrosion coating on the back surface of the ceiling,
The method for constructing a ceiling portion of a water-containing gas holder according to claim 2, wherein after the spacer bolt is removed, anticorrosion coating is applied to the inner surface of the bolt hole and the contact portion of the spacer bolt. The construction method of the ceiling part of the water-containing gas holder according to claim 1, wherein the spacer is a refractory material or a heat insulating material placed on the ceiling frame. The construction method of the ceiling part of the water-containing gas holder according to any one of claims 1 to 4, wherein the ceiling frame is painted in advance before assembly. The ceiling part of the water-containing gas holder according to any one of claims 1 to 5, wherein the steel sheet for ceiling plate is preliminarily coated with anticorrosion before being laid on the ceiling frame. Construction method. The method for constructing a ceiling part of a water-containing gas holder according to claim 6, wherein the anticorrosion coating applied in advance to the steel sheet for ceiling plate is applied to a portion excluding a heat-affected part of welding.

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