JP2001327853A - Chemical decontamination liquid decomposition device provided with catalyst column and catalyst column - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chemical decontamination decomposition device provided with a catalyst column capable of preventing the flow-out of a catalyst to a line and preventing the convection of the catalyst due to a decomposition gas generated in the catalyst column. SOLUTION: In the chemical decontamination liquid decomposition device for decomposing the chemical decontamination liquid and provided with the catalyst column, the catalyst column is provided with an inlet pipe line making the chemical decontamination liquid flow in, the catalyst for decomposing the chemical decontamination liquid flowing in from the inlet pipe line, an outlet pipe line for making the chemical decontamination liquid passed through the catalyst flow out, an inlet mesh filter provided between the inlet pipe line and the catalyst, an outlet mesh filter arranged between the catalyst and the outlet pipe line and a catalyst filling port for filling the catalyst, the outlet mesh filter is mounted to come into close contact with the inside surface of the catalyst column and the inside surface of the catalyst filling port and catalyst press structure for suppressing the convection of the catalyst is mounted inside the catalyst filling port.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalyst tower and a chemical decontamination liquid decomposition apparatus provided with the catalyst tower.

[0002]

2. Description of the Related Art FIG. 6 shows the structure of a conventional catalyst tower. In this catalyst tower, the chemical decontamination liquid flowing from the inlet pipe 11 is reversed and distributed in the lower chamber 12, passes through the inlet mesh filter 13 and rises between the catalysts 14,
It passed through the outlet mesh filter 15 and flowed out of the outlet pipe 16. When the catalyst is filled in the catalyst tower container 18, the catalyst tower upper lid 17 and the outlet mesh filter 15 are used.
Removed and filled with catalyst. Also, the catalyst tower container 18
The outlet mesh filter 15 has a structure in which the spring 21 presses the catalyst in order to prevent the catalyst from convection due to the gas generated by the decomposition reaction of the chemical decontamination liquid therein. Therefore, the outlet mesh filter 15 needs to have a removable and movable structure.

[0003]

In order to make the outlet mesh filter 15 detachable and movable, it is necessary to penetrate between the outer peripheral portion of the outlet mesh filter 15 and the inner wall of the catalyst tower vessel 18 and through the inlet pipe 11 of the outlet mesh filter 15. It is necessary to provide a gap in the part. The gap needs to be made as small as possible from the viewpoint of preventing the catalyst from flowing out. By penetrating the inlet pipe 11 from the side surface of the catalyst tower vessel 18, the penetration section of the inlet mesh 11 of the outlet mesh filter 15 can be eliminated, but the height of the catalyst tower vessel 18 increases and the catalyst tower 5 is housed. It is not economical because the size of the shielding container becomes large. As a method for reducing the gap, the outer peripheral portion of the outlet mesh filter 15 and the inlet pipe 1 are used.
It is conceivable to provide an O-ring at the through portion of
When the ring is provided, the mobility of the outlet mesh filter 15 is reduced, and the function of holding down the catalyst may be reduced.

[0004] It is an object of the present invention to provide a chemical decontamination liquid decomposer equipped with a catalyst tower capable of preventing the catalyst from flowing out into the system and preventing convection of the catalyst due to the decomposition gas generated in the catalyst tower. It is to be.

[0005]

According to one embodiment of the present invention, a catalyst tower is provided between a catalyst for decomposing a chemical decontamination liquid and an outlet pipe for discharging the chemical decontamination liquid. Outlet mesh filter, and a catalyst charging port for charging the catalyst, the outlet mesh filter is installed in close contact with the inner surface of the catalyst tower and the inner surface of the catalyst charging port, and convection of the catalyst inside the catalyst charging port A catalyst holding mechanism for suppressing the pressure is provided.

As a specific configuration, a catalyst filling port is provided in the upper cover of the catalyst tower, and a catalyst holding mechanism is provided in the catalyst filling port. Further, the outlet mesh filter has a structure in which the inner wall of the catalyst tower container and the catalyst filling port are in close contact with each other.

According to this, the catalyst can be directly charged into the catalyst tower container from the catalyst charging port, and it is not necessary to remove the catalyst tower upper lid and the outlet mesh filter.
Further, by disposing the catalyst holding mechanism in the catalyst filling port, it is not necessary to move the outlet mesh filter. By adopting such a structure, it is not necessary to make the outlet mesh filter detachable and movable, so that the outlet mesh filter can be in close contact with the inner wall of the catalyst tower container and the catalyst charging port.

Therefore, it is possible to reliably prevent the catalyst from flowing out of the outlet mesh filter. Further, since the catalyst can be reliably held down by the catalyst holding mechanism provided in the catalyst filling port, convection of the catalyst due to the decomposition gas can be prevented.

According to the present invention, a catalyst tower capable of preventing the catalyst from flowing out into the system and preventing convection of the catalyst due to a decomposition gas generated in the catalyst tower, and a chemical decontamination provided with the catalyst tower A liquid decomposition device can be provided.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment will be described with reference to FIGS. The arrows shown in each figure indicate the flow of the chemical decontamination solution.

(Embodiment 1) FIG. 2 shows the overall configuration of a chemical decontamination liquid decomposition apparatus when decomposing a chemical decontamination liquid. The chemical decontamination liquid flowing out of the decontamination target 1 is pressurized (pressurized) by the pump 2 and flows into the resin tower 3 to remove metal ions. The chemical decontamination liquid flowing out of the resin tower 3 is supplied to the heater 4
After the temperature is increased, hydrogen peroxide is injected to further promote the decomposition, and then flows into the catalyst tower 5. The chemical decontamination liquid is decomposed in the catalyst tower 5, the decomposed gas is exhausted, and the chemical decontamination liquid performs a closed loop operation returning to the decontamination target 1.

FIG. 1 shows the structure of an embodiment of the catalyst tower 5. The chemical decontamination liquid flows in from the inlet pipe 11 of the catalyst tower 5, and its flow direction is reversed in the lower chamber 12. The flow of the chemical decontamination liquid is distributed in the lower chamber 12 and passes through the inlet mesh filter 13. Inlet mesh filter 1
The chemical decontamination liquid that has passed through 3 is decomposed by a chemical reaction while passing between the catalysts 14. The gas generated by the decomposition passes through the outlet mesh filter 15 together with the chemical decontamination liquid, and flows out of the outlet pipe 16. When the catalyst is charged into the catalyst tower 5, the catalyst can be directly charged by removing the lid of the catalyst charging port 19 and the catalyst pressing mechanism 20.

The outlet mesh filter 15 of the catalyst tower 5 is
It is welded to the inner side wall of the catalyst tower vessel 18 and the lower end of the catalyst filling port 19. Further, the outlet mesh filter 15
Is also welded to the outer side wall of the inlet pipe 11 at the penetrating portion of the inlet pipe 11. For this reason, the outlet mesh filter 15 has a structure in which there is no gap such that the catalyst 14 flows out to the outlet pipe 16 side. Thus, the outlet mesh filter 15 can prevent the catalyst 14 from flowing out.

In the catalyst charging port 19 of the catalyst tower 5,
A catalyst holding mechanism 20 is provided. Catalyst holding mechanism 20
Is constituted by a weight, and has a function of pressing the catalyst 14 by applying pressure to the catalyst 14 by its gravity. Thereby, it is possible to prevent the catalyst 14 from being convected by the decomposition gas. As an example of the catalyst holding mechanism, when the material of the catalyst holding mechanism 20 is made of lead and the thickness thereof is set to 180 mm, the catalyst 14 can be held at a pressure of about 0.02 MPa.

(Embodiment 2) FIG. 3 shows another embodiment of the present invention. In the present embodiment, the inlet pipe 11 is installed at the lower part of the side surface of the catalyst tower vessel 18 and has a structure directly connected to the lower chamber 12. In this case, the same effect as in the first embodiment can be obtained. Furthermore, in this embodiment, since the penetration portion of the inlet pipe 11 can be eliminated in the outlet mesh filter 15, the productivity of the outlet mesh filter 15 can be improved.

(Embodiment 3) FIG. 4 shows another embodiment. In the present embodiment, the structure of the outlet mesh filter 15 is disk-shaped. In this case, the same effect as in the first embodiment can be obtained. Furthermore, in the present embodiment, the structure of the outlet mesh filter 15 can be simplified, so that the manufacturability can be improved.

(Embodiment 4) FIG. 5 shows another embodiment. In this embodiment, the catalyst holding mechanism 20 installed in the catalyst charging port 19 is constituted by a spring 21 and a catalyst holding plate 22. In this case, the same effect as in the first embodiment can be obtained.
Furthermore, in the present embodiment, the structure in which the catalyst is held down by the spring 21 eliminates the need to remove the heavy weight when filling the catalyst, so that the workability of filling the catalyst can be improved.

In the second, third, and fourth embodiments, other embodiments of the inlet pipe 11, the outlet mesh filter 15, and the catalyst holding mechanism 20 are shown. Can be combined. In short, the outlet mesh filter 15 may be brought into close contact with the inner wall of the catalyst tower container 18 and the catalyst filling port 19. Further, the catalyst pressing mechanism 20 may have any structure as long as it can apply pressure to the catalyst, and may pressurize by pneumatic or hydraulic pressure.

(Embodiment 5) FIG. 7 shows another embodiment. FIG. 8 shows the overall configuration of the chemical decontamination liquid decomposition apparatus of the present embodiment. The chemical decontamination liquid decomposition apparatus of the present embodiment has five operation modes of oxidation, oxidizing agent decomposition, reduction, reducing agent decomposition, and purification. Hereinafter, each mode will be described.

First, the oxidation mode will be described. In this embodiment, potassium permanganate is used as an oxidizing agent. The valves 36, 37, 38, 39, 32, 33 are closed and the valves 53, 52, 35, 34 are open. The chemical decontamination liquid into which the oxidizing agent has been injected from the oxidizing agent injection device 54 flows into the decontamination target 1, and decontaminates the decontamination target 1. The chemical decontamination liquid that has flowed out of the decontamination target 1 is pressurized (pressurized) by the pump 2, then controlled to a predetermined temperature by the heater 4, and returns to the decontamination target 1 again.

Next, the oxidizing agent decomposition mode will be described. In this embodiment, oxalic acid is used to decompose the oxidizing agent. The valves 36, 37, 38, 39, 32, 33 are closed and the valves 53, 52, 35, 34 are open. The chemical decontamination liquid flowing out of the decontamination target 1 is pressurized (pressurized) by the pump 2, a reducing agent (oxalic acid) is injected from the reducing agent injection device 55, and the oxidizing agent is decomposed. After that, the temperature is raised by the heater 4 and returns to the decontamination target 1. In this mode, the heater 4 controls the temperature to a predetermined temperature.

Next, the reduction mode will be described. In this mode, valves 36, 39, 32, 33, 53, 52 are closed and valves 37, 38, 35, 34 are open. The chemical decontamination liquid into which the reducing agent (oxalic acid) has been injected from the reducing agent injection device 55 flows into the decontamination target 1, and the decontamination target 1
Decontamination. The chemical decontamination liquid that has flowed out of the decontamination target 1 is pressurized (pressurized) by the pump 2 and is supplied to the cationic resin tower 3a.
The impurities eluted by the decontamination through are removed. afterwards,
The temperature is controlled to a predetermined value by the heater 4 and the process returns to the decontamination target 1 again.

Next, the reducing agent decomposition mode will be described. In this mode, the valves 36, 39, 35, 34, 52,
53 is closed and valves 37, 38, 32, 33 are open. The chemical decontamination liquid flowing out of the decontamination target 1 is pressurized (pressurized) by the pump 2 and passes through the cationic resin tower 3a to remove impurities. Thereafter, the temperature is controlled to a predetermined value by the heater 4, hydrogen peroxide is injected by the hydrogen peroxide injection device 30, and flows into the catalyst tower 51. The chemical decontamination liquid is decomposed by the hydrogen peroxide and the catalyst in the catalyst tower 51, and the decomposed gas is discharged from the exhaust device 40.
Thereafter, the chemical decontamination liquid returns to the decontamination target 1. By performing this circulation operation, the chemical decontamination liquid is decomposed. Also in this mode, the heater 4 controls the temperature to a predetermined temperature.

Next, the purification mode will be described. In this mode, valves 37, 38, 32, 33, 52, 53 are closed and valves 36, 39, 35, 34 are open. The chemical decontamination liquid flowing out of the decontamination target 1 is pressurized (pressurized) by the pump 2 and cooled by the cooler 31.
Then, impurities remaining in the cation tower 3a are removed through the mixed-bed resin tower 3b, and are heated again by the heater 4.

The decontamination target 1 is decontaminated by repeatedly performing each mode described above in the order of the oxidation mode, the oxidant decomposition mode, the reduction mode, the reducing agent decomposition mode, and the purification mode.

In this embodiment, the operator manually opens and closes each valve when changing each mode. However, an electric opening and closing device may be used. When using an electric device,
Workers' workload may be small.

Next, the details of the catalyst tower 51 used in this embodiment will be described. FIG. 7 shows the catalyst tower 5. The chemical decontamination liquid flows from the inlet pipe 11 of the catalyst tower 5 (the pipe on the side of the valve 32 in FIG. 8) and is guided to the lower chamber 12. The flow of the chemical decontamination liquid is distributed in the lower chamber 12 and passes through the inlet mesh filter 13. Inlet mesh filter 13
The chemical decontamination liquid that has passed through is decomposed by a chemical reaction while passing between the catalysts 14. The gas generated by the decomposition passes through the outlet mesh filter 15 together with the chemical decontamination liquid, and flows out of the outlet pipe 16 (in FIG. 8, the pipe on the valve 33 side). When the catalyst is charged into the catalyst tower 5, the catalyst is directly charged by removing the lid of the catalyst charging port 19 and the catalyst holding mechanism 20. The outlet mesh filter 15 of the catalyst tower 5 is welded to the inner side wall of the catalyst tower vessel 18 and the lower end of the catalyst filling port 19. Further, the outlet mesh filter 15 is also welded to the outer side wall of the inlet pipe 11 at the penetrating portion of the inlet pipe 11. For this reason,
The outlet mesh filter 15 is configured such that the catalyst 14
There is no gap that flows out to the side of No. 6. Thereby, the catalyst 14 can be prevented from flowing out to the outlet pipe 16 side.
A catalyst holding mechanism 20 is provided in the catalyst charging port 19 of the catalyst tower 5. The catalyst holding mechanism 20 is formed of a weight, and exerts a function of pressing the catalyst 14 by applying pressure to the catalyst 14 by gravity applied to the weight. Thereby, it is possible to prevent the catalyst 14 from convection due to the decomposition gas generated when the chemical decontamination liquid is decomposed. The catalyst holding mechanism used in this embodiment is a catalyst holding mechanism 2
The material 14 is made of lead and has a thickness of 180 mm, and can press the catalyst 14 at a pressure of about 0.02 MPa.

The catalyst tower 51 has a lower reinforcing plate 25 provided below the inlet mesh filter 13 and an upper reinforcing plate 24 provided above the outlet mesh filter 15. Thereby, the load generated by the flow of the catalyst 14, the catalyst holding mechanism 20, and the chemical decontamination liquid is withheld.
The strength of the mesh filter can be reinforced. By the reinforcement, the amount of deformation of the mesh caused by the flow of the chemical decontamination liquid can be reduced as compared with the case where the lower reinforcing plate 25 and the upper reinforcing plate 24 are not provided. The lower reinforcing plate 25 and the upper reinforcing plate 24 are both perforated, and the chemical decontamination liquid is
It is easy to flow.

The mesh sizes of the inlet mesh filter 13 and the outlet mesh filter 15 are made smaller than the size of the catalyst 14 to be used. When the size of the catalyst 14 is 4 to 8 mesh, the size of the mesh filter is about 20 mesh. When the size of the catalyst 14 is 10 to 20 mesh, the size of the mesh filter is about 40 mesh. When the mesh size is further reduced, the wire diameter of the mesh is reduced and the strength is reduced. For example, by superposing a mesh filter of 70 mesh and a mesh filter of 20 mesh, the mesh size is reduced. Thus, the strength of the mesh filter can be ensured.

After using the catalyst tower 51, the catalyst tower 5
The liquid remaining therein is discharged to the inlet pipe 11 by applying gas pressure from the outlet pipe 16 to the inside of the catalyst tower 51. A groove 26 is formed in the lower plate 23 of the catalyst tower, and an end of the inlet pipe 11 is provided on a lower surface of the groove. A hole 27 is provided at an end of the inlet pipe 11. Thereby, it can be provided below the upper surface 23U of the catalyst tower lower plate in the vertical direction. When a liquid is contained in the catalyst tower 51, the liquid is pushed out from the inlet pipe 11 by applying gas pressure from the outlet pipe 16. At this time, since the end of the inlet pipe 11 is provided in the groove 26, at least the liquid above the upper surface 23U of the lower plate of the catalyst tower in the vertical direction can be discharged. Thereby, after using the catalyst tower 51, the catalyst tower 5
Since the amount of the decontamination liquid remaining in 1 can be reduced, the radiation dose after use of the catalyst tower 51 can be reduced. Furthermore, the exposure dose of the worker approaching the catalyst tower 51 after using the catalyst tower 51 can be further reduced. Also,
Storage of the catalyst tower becomes easy. Note that the height of the hole 27 is
By making the depth smaller than 6, the amount of liquid remaining in the catalyst tower 51 can be reduced.

If the diameter of the inlet pipe 11 is large, this structure may not be able to sufficiently discharge the remaining liquid. In that case, a discharge pipe having a small diameter is installed separately from the inlet pipe 11, and the connection point between the catalyst tower lower plate 23 and the pipe has the same structure as the connection of the inlet pipe 11 described above. The liquid that cannot be cut can be reduced.

Further, the upper surface of the lower plate of the catalyst tower is
May be mortar-shaped around the position connected to the lower plate 23 of the catalyst tower. Thereby, when the liquid in the catalyst tower 51 is discharged, the liquid flows into a position connected to the inlet pipe 11 and the lower plate 23 of the catalyst tower, so that the discharge can be facilitated.

According to the embodiment described above, it is possible to charge the catalyst into the catalyst tower container directly from the catalyst tower charging port. In addition, by installing the catalyst holding mechanism in the catalyst filling port, there is no need to make the outlet mesh filter detachable and movable, so that the outlet mesh filter is in close contact with the inner wall of the catalyst tower container and the catalyst filling port. It can be. Therefore, the outflow of the catalyst from the outlet mesh filter can be reliably prevented. Further, since the catalyst can be reliably held down by the catalyst holding mechanism provided in the catalyst filling port, convection of the catalyst due to the decomposition gas can be prevented.

[0034]

According to the present invention, a chemical decontamination liquid decomposing apparatus having a catalyst tower capable of preventing the catalyst from flowing out into the system and preventing convection of the catalyst due to the decomposition gas generated in the catalyst tower. Can be provided.

[Brief description of the drawings]

FIG. 1 shows a catalyst tower structure according to one embodiment of the present invention.

FIG. 2 is an overall configuration of a chemical decontamination apparatus when a chemical decontamination solution is decomposed.

FIG. 3 is a catalyst tower structure according to one embodiment of the present invention.

FIG. 4 shows a catalyst tower structure according to one embodiment of the present invention.

FIG. 5 is a catalyst tower structure according to one embodiment of the present invention.

FIG. 6 shows a conventional catalyst tower structure.

FIG. 7 is a detailed structure of the embodiment of the present invention shown in FIG. 1;

FIG. 8 is a diagram showing a system diagram of a fourth embodiment.

[Explanation of symbols]

1 ... decontamination target, 2 ... pump, 3 ... resin tower, 4 ... heater,
5 ... catalyst tower, 11 ... inlet piping, 12 ... lower chamber, 13 ... inlet mesh filter, 14 ... catalyst, 15 ... outlet mesh filter, 16 ... outlet piping, 17 ... catalyst tower top lid, 18 ...
Catalyst tower container, 19: catalyst filling port, 20: catalyst holding mechanism,
21: spring, 22: catalyst holding plate.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Katsuo Yokota, Inventor 3-2-1 Sachimachi, Hitachi, Ibaraki Prefecture Inside Hitachi Engineering Co., Ltd. (72) Yasushi Kobayashi 3-2-2, Sachimachi, Hitachi, Ibaraki No. 1 Hitachi Engineering Co., Ltd. (72) Inventor Kazumi Anazawa 3-1-1 Sachimachi, Hitachi-shi, Ibaraki Pref. Hitachi, Ltd. Nuclear Power Division

Claims (11)

[Claims] 1. A chemical decontamination liquid decomposer having a catalyst tower for decomposing a chemical decontamination liquid, wherein the catalyst tower has an inlet pipe through which the chemical decontamination liquid flows, and a chemical pipe flowing through the inlet pipe. A catalyst that decomposes the decontamination solution, an outlet pipe that allows the chemical decontamination solution that has passed through the catalyst to flow out, an inlet mesh filter that is provided between the inlet pipe and the catalyst, and the catalyst and the outlet pipe. An outlet mesh filter provided therebetween, and a catalyst charging port for charging the catalyst, wherein the outlet mesh filter is disposed in close contact with an inner surface of the catalyst tower and an inner surface of the catalyst charging port, and the catalyst filler is provided. A chemical decontamination liquid decomposition apparatus, wherein a catalyst holding mechanism for suppressing convection of the catalyst is provided inside the mouth. 2. A casing, which is filled with a catalyst for decomposing a chemical decontamination liquid in a space surrounded by a mesh and a part of the casing, wherein the casing is disposed vertically below the catalyst. And the catalyst is an inlet pipe that guides and discharges the chemical decontamination solution from the outside of the housing to the inside of the housing separated by the mesh, and the chemical decontamination solution that has passed through the catalyst is transferred vertically to the catalyst. A catalyst tower, comprising: an upper side in the direction and the catalyst, and an outlet pipe leading from the side separated by the mesh to the outside of the casing. 3. The catalyst tower according to claim 2, wherein the catalyst is pressurized by a weight from a part of a space surrounded by the mesh and a part of the housing. 4. The catalyst tower according to claim 2, wherein the meshes are formed by overlapping meshes having different sizes. 5. The catalyst tower according to claim 2, wherein the mesh is overlapped with a reinforcing plate having a hole in a metal plate. 6. The terminal according to claim 2, wherein an end of the inlet pipe inside the housing is opened inside a groove provided on a vertically lower surface of the housing. Catalyst tower. 7. The two surfaces at both ends of a cylindrical housing are first
A first mesh and a second mesh, which divide the space inside the housing, from the top in the vertical direction to the inside of the housing in which the first surface is located vertically above the second surface. A first surface, a first mesh, a second mesh, and a second surface are provided in this order, and a chemical decontamination liquid is guided from the outside of the housing to a space between the second surface and the second mesh. 1 pipe and a second pipe for guiding the chemical decontamination solution to the outside of the housing from a space between the first surface and the first mesh are connected, and between the first mesh and the second mesh. The first space is provided with a filling path for filling the catalyst, and the first space is filled with a catalyst for decomposing the chemical decontamination solution. The catalyst has a part of the filling path and the catalyst. Pressure is applied by the weight contacting a part of the catalyst filled in the first space. A catalyst tower characterized in that: 8. The apparatus according to claim 7, wherein the filling path is the first filling path.
Is connected to a vertically upper portion of the space by a first connection portion, and a horizontal cross-sectional area of the first space increases from the first connection portion to a vertically lower side. Catalyst tower. 9. The catalyst tower according to claim 7, wherein the meshes are formed by overlapping meshes having different sizes. 10. The catalyst tower according to claim 7, wherein the mesh is overlapped with a reinforcing plate having a hole in a metal plate. 11. The terminal according to claim 7, wherein the first end of the first pipe inside the housing is opened in a vertically downward groove provided in the second surface inside the housing. A catalyst tower, characterized in that: