JP2018095914A - Cleaning method and cleaning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaning method and cleaning device that use an acidic cleaning liquid capable of alleviating fire management.SOLUTION: According to a cleaning method of the present invention, an acidic cleaning liquid W in which a hydrogen storage alloy is mixed is supplied to a device to be cleansed 3 to remove scale attached to the inside of the device to be cleansed 3 and recover at least a part of hydrogen generated in the device to be cleansed 3 with the hydrogen storage alloy. The hydrogen storage alloy included in microcapsules formed from a substance that hydrogen passes through may be mixed with the cleaning liquid W. The density of the microcapsules in which the hydrogen storage alloy is included is adjusted to a predetermined range the same as the density of the cleaning liquid followed by mixing in the cleaning liquid.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a cleaning method and a cleaning apparatus using an acidic cleaning liquid.

For example, in a boiler water supply system of a thermal power generation system, chemical cleaning is performed in which a scale (Fe ₂ O ₃ or the like) adhering to the inner wall of a boiler wall tube of a boiler is dissolved using an acidic cleaning liquid during periodic inspections or the like ( Patent Document 1).

Members such as heat transfer tubes constituting the boiler water supply system contain iron (Fe) components. During chemical cleaning, it is necessary to fill the equipment to be cleaned with an acidic cleaning solution, but by using an acidic cleaning solution, not only the scale but also part of the iron contained in the component chemically reacts to produce hydrogen gas. (H ₂ ) is generated.
Oxidation reaction: Fe → Fe ²⁺ + 2e ⁻
Reduction reaction: 2H ⁺ + 2e ⁻ → H ₂ ↑

  The conventional thermal power generation system has a configuration in which most of the hydrogen gas generated during chemical cleaning is accumulated in a region in the upper part of the steam-water separator connected to the downstream side of the furnace wall pipe. During chemical cleaning, the hydrogen gas accumulated in the upper part is released into the atmosphere by degassing through an air vent or the like. After the chemical cleaning is completed, hydrogen gas remaining in the cleaning system is also released out of the system in the process of blowing and draining the cleaning liquid while enclosing nitrogen in the cleaning system.

JP-A-2006-17188 (paragraph 0007)

  However, since hydrogen gas generation during chemical cleaning occurs at various locations in the cleaning system, hydrogen may accumulate in unexpected locations. Since hydrogen is explosive at room temperature, consideration must be given to the release of hydrogen so that the lower explosion limit: 4% is not exceeded, and as a safety measure, it is necessary to manage the fire around the boiler cleaning operation during chemical cleaning. Become.

  As a fire management, the fire work around is not carried out by setting a fire strict (no entry) area. If the boiler is chemically cleaned to prevent such fires from being strictly prohibited, welding work and the like cannot be performed in parallel, and an extra period of inspection is required. When stopping a large coal-fired boiler, an oil-fired boiler may be operated separately to generate power. Therefore, if the periodic inspection period is extended for several days, the impact of cost increases due to the difference in fuel prices. Therefore, there is a need for a chemical cleaning method that can ease firearm management.

  This invention is made | formed in view of such a situation, Comprising: It aims at providing the washing | cleaning method and washing | cleaning apparatus using the acidic washing | cleaning liquid which can reduce the restriction | limiting of a fire management.

  In order to solve the above problems, the cleaning method and the cleaning apparatus of the present invention employ the following means.

  The present invention supplies an acidic cleaning liquid mixed with a hydrogen storage alloy at the time of cleaning to a device to be cleaned, removes the scale attached to the device to be cleaned, and generates hydrogen generated in the device to be cleaned at the time of cleaning. A cleaning method for recovering at least a part of the hydrogen storage alloy is provided.

  The hydrogen storage alloy mixed in the cleaning liquid occludes (recovers) hydrogen in the cleaning system while being transported in the cleaning system along with the flow of the cleaning liquid. Thereby, it is possible to prevent hydrogen from accumulating at an unexpected position in the cleaning system.

  In one embodiment of the present invention, the hydrogen storage alloy encapsulated in microcapsules formed of a substance through which hydrogen can pass is mixed in the cleaning liquid.

  By encapsulating the hydrogen storage alloy in a microcapsule through which hydrogen can pass, the hydrogen storage alloy can be easily conveyed along with the flow of the cleaning liquid. The hydrogen storage alloy turns into powder due to embrittlement when it repeatedly stores and releases hydrogen, but even if the hydrogen storage alloy encapsulated in the microcapsule stays in the microcapsule, it can be easily recovered from the cleaning liquid. It is.

  In one embodiment of the present invention, the microcapsules containing the hydrogen storage alloy are adjusted to a predetermined range that is equivalent to the specific gravity of the cleaning liquid, and are mixed into the cleaning liquid.

  By adjusting the specific gravity within a predetermined range equivalent to that of water, the microcapsules containing the hydrogen storage alloy are more easily transported along with the flow of the cleaning liquid. Thereby, it is possible to prevent the microcapsules containing the hydrogen storage alloy from being accumulated in a part of the region to be cleaned without being transported by the flow of the cleaning liquid.

  In one aspect of the invention described above, the specific gravity of the microcapsules containing the hydrogen storage alloy is adjusted so as to be within a predetermined range of a plurality of different specific gravity, and mixed into the cleaning liquid.

  There are those in which the specific gravity of the microcapsules enclosing the hydrogen storage alloy is in a plurality of predetermined ranges. For example, it is easy to disperse in the cleaning liquid by making it slightly larger and slightly smaller than the cleaning liquid (specific gravity: about 1). The slight indicates a difference in specific gravity within ± 10%. A microcapsule containing a hydrogen storage alloy having a slightly higher specific gravity is likely to exist in the lower part in the direction of gravity. A microcapsule in which a hydrogen storage alloy having a small specific gravity is included is likely to exist in the upper part in the direction of gravity. In addition, by making the specific gravity slightly larger than the cleaning liquid water in the initial state, after the hydrogen is occluded to some extent, the specific gravity approaches the specific gravity of the cleaning liquid and becomes equivalent, so that it is more easily transported by the flow of cleaning liquid, Hydrogen generated on the downstream side can be occluded.

  In one aspect of the invention, the cleaning liquid is discharged from the device to be cleaned, and the discharged cleaning liquid is supplied to a collection unit to collect sludge in the cleaning liquid.

  By collecting the sludge, which is the scale peeled off by the collection unit, the microcapsules containing the cleaning liquid and the hydrogen storage alloy can be circulated without recirculating the sludge to the equipment to be cleaned. Sludge contains a magnetic material and is attracted to the magnet.

  In one aspect of the invention, the collection portion includes an introduction portion and a discharge portion for the cleaning liquid, and the cleaning liquid passes through a region including a region centered on a straight line connecting the introduction portion and the discharge portion. It is good to partition with a partition plate so that at least the gravitational direction of the discharge part may be covered between the main channel region and the water surface of the cleaning liquid stored in the collection part.

  When the hydrogen storage alloy contained in the capsule stores a predetermined amount or more of hydrogen, the specific gravity is reduced as compared with before hydrogen storage, and the hydrogen storage alloy floats to the water surface side of the cleaning liquid, which is the upper part in the gravity direction. The microcapsules that have floated to the water surface side are not easily transported along with the flow of the cleaning liquid, and the hydrogen storage capacity is also reduced. According to the aspect of the invention, the partition plate can prevent the microcapsules that have occluded hydrogen and floated to the water surface side from remaining in the water surface side region and recirculated to the main flow channel region again.

  In one embodiment of the present invention, at least a part of the microcapsules having the specific gravity smaller than that of water and enclosing the hydrogen storage alloy floating on the surface of the cleaning liquid may be recovered from the device to be cleaned.

  In one embodiment of the present invention, at least a part of the microcapsules having the specific gravity smaller than water and enclosing the hydrogen storage alloy floating on the water surface of the cleaning liquid is extracted from the cleaning target device.

  When the specific gravity of the microcapsules containing the hydrogen storage alloy is smaller than that of water, the microcapsules float on the upper part in the gravity direction of the cleaning liquid stored in the apparatus to be cleaned. If the cleaning system has a configuration in which the cleaning liquid flows in the direction penetrating the water surface, if a large amount of microcapsules accumulates in the upper part of the gravity direction (water surface), the flow of the cleaning liquid may be blocked or delayed. Can be. According to one aspect of the present invention, a smooth flow of the cleaning liquid in the cleaning system can be maintained by collecting at least a part of the microcapsules floating on the water surface and removing it from the cleaning liquid circulation system.

  In one embodiment of the present invention, the microcapsules containing the hydrogen storage alloy having a specific gravity smaller than the predetermined range may be heated to a predetermined temperature, and the hydrogen adsorbed on the hydrogen storage alloy may be desorbed and regenerated. .

  When heated to a predetermined temperature or higher, hydrogen stored in the hydrogen storage metal is desorbed and released out of the microcapsule. Thereby, the hydrogen storage ability of the hydrogen storage alloy can be regenerated.

  The present invention includes a circulation unit that circulates an acidic cleaning liquid to an apparatus to be cleaned, a hydrogen storage alloy tank that stores a hydrogen storage alloy, and a hydrogen storage alloy mixing unit that mixes the hydrogen storage alloy into the cleaning liquid. A cleaning apparatus is provided.

  In one embodiment of the present invention, the hydrogen storage alloy is included in a microcapsule formed of a substance through which hydrogen can pass.

  In one aspect of the invention described above, the specific gravity of the microcapsules containing the hydrogen storage alloy is a value within a predetermined range that is equivalent to the specific gravity of the cleaning liquid.

  In one embodiment of the present invention, the hydrogen storage alloy tank may contain a plurality of microcapsules enclosing the hydrogen storage alloy in a predetermined range having different specific gravities.

  In one aspect of the invention, the circulation unit includes a collection unit, and the collection unit includes collection means for collecting sludge in the cleaning liquid.

  In one aspect of the invention described above, the collecting means may be a magnet.

  In one aspect of the invention, the collection part includes an introduction part and a discharge part of the cleaning liquid, and a partition plate, and the partition plate is an area centered on a straight line connecting the introduction part and the discharge part. Between the main flow channel region of the cleaning liquid passing through the region including the water surface of the cleaning liquid accommodated in the collection portion and at least a position in the gravity direction of the discharge portion. .

  In one aspect of the invention, there may be provided a recovery means connected to the equipment in the cleaning system, having a specific gravity smaller than that of water and sucking the microcapsules enclosing the hydrogen storage alloy floating on the water surface of the cleaning liquid. Good.

  In one embodiment of the present invention, a regeneration unit is further provided, and the regeneration unit is connected to the collection unit, and collects the microcapsules containing the cleaning liquid and the hydrogen storage alloy contained in the collection unit. Hydrogen is removed from the recovery means, the regeneration tank that contains the recovered cleaning liquid and the microcapsules containing the hydrogen storage alloy, and the microcapsule that contains the recovered hydrogen storage alloy in the regeneration tank. Heating means for heating to a possible temperature, and the regeneration tank may include an exhaust port for the desorbed hydrogen.

  In one aspect of the invention, there may be provided an extraction means connected to the equipment in the cleaning system, and having a specific gravity smaller than that of water and extracting the microcapsules containing the hydrogen storage alloy floating on the water surface of the cleaning liquid. .

  ADVANTAGE OF THE INVENTION According to this invention, it can prevent that hydrogen accumulates in a washing | cleaning system | strain by making the hydrogen storage alloy occlude the hydrogen which generate | occur | produces when wash | cleaning apparatus wash | cleaned with an acidic washing | cleaning liquid. Thereby, the safety | security of the operation | work in a periodic inspection etc. improves. Establishing safety can alleviate restrictions on fire management during cleaning. As a result, it is possible to reduce the execution of other work such as welding work in the surroundings and perform the work at the same time, thereby shortening the periodic inspection period.

It is an equipment distribution diagram of a washing device concerning a 1st embodiment. It is a schematic diagram of a collection part. It is a schematic diagram of a reproducing part. It is a schematic diagram explaining a sucking means.

  In the following, embodiments of the cleaning method and the cleaning apparatus according to the present invention will be described by taking chemical cleaning of a boiler water supply system of a thermal power generation system as an example. However, the present invention is not limited to a thermal power generation system, and can be applied to other devices that generate hydrogen in a cleaning system by cleaning with an acidic cleaning liquid.

[First Embodiment]
FIG. 1 is an equipment system diagram of the cleaning apparatus according to the present embodiment. FIG. 1 shows a case where the cleaning device is installed in the thermal power generation system during maintenance. In a thermal power generation system, a scale gradually adheres to the inside of a heat transfer pipe such as a furnace wall pipe of a boiler, thereby reducing the thermal conductivity of the heat transfer pipe. Therefore, the cleaning target device in the present embodiment will be described as a furnace wall tube. FIG. 1 shows a part (a high pressure feed water heater 1, a economizer 2, a boiler wall tube 3, a steam separator 4 and a superheater 5) centering on a furnace wall tube of a boiler feed water system of a thermal power generation system. ). Although the high-pressure feed water heater 1, the economizer 2, the furnace wall pipe 3, the steam separator 4 and the superheater 5 are sequentially connected by piping, this connection order is not limited.

  The cleaning apparatus 10 includes a circulation unit 11 for circulating an acidic cleaning liquid to a device to be cleaned, a hydrogen storage alloy mixing unit 12 for mixing a hydrogen storage alloy into the cleaning liquid, and a makeup water tank 13 for storing makeup water serving as a base of the cleaning liquid. And a chemical injection part 14 for injecting an acidic chemical for chemical cleaning into the makeup water.

  The circulation unit 11 includes a circulation path 15 (15a, 15b, 15c and 15d), a steam heating unit 16, a liquid feeding unit 17, a sludge separation unit 18, and a collection unit 19.

  The circulation path 15 (15a, 15b, 15c and 15d) has one end connected to the steam separator 4 and the other end connected to the economizer 2 (or a pipe connected to the upstream side of the economizer 2). Here, the economizer 2 → the furnace wall tube 3 → the steam / water separator 4 → the circulation path 15 → the economizer 2 is hereinafter referred to as a cleaning system. The circulation path 15 (15a, 15b, 15c and 15d) is a pipe or the like through which the cleaning liquid can flow.

  The steam heating unit 16 is connected to the drainage port of the steam separator 4 through the circulation path 15a. The steam heating unit 16 is a means for heating the liquid (cleaning liquid W) separated by the steam separator 4 and circulating in the cleaning system to a predetermined temperature to maintain the chemical cleaning capability. In the present embodiment, the predetermined temperature is, for example, about 60 ° C. to 80 ° C. For example, the steam heating unit 16 conveys and introduces steam from an adjacent power plant, auxiliary boiler, and temporary boiler, and heats the cleaning liquid W to a predetermined temperature.

  The liquid feeding unit 17 is connected to the downstream side of the steam heating unit 16 through the circulation path 15b. The liquid feeding unit 17 is, for example, a liquid feeding pump.

  The sludge separation unit 18 is connected to the downstream side of the liquid feeding unit 17 through the circulation path 15c. The sludge separation unit 18 is a means for separating the cleaning liquid W sent from the liquid feeding unit 17 into a first cleaning liquid Wa from which coarse sludge has been separated and a second cleaning liquid Wb containing coarse sludge. The sludge separator 18 may be capable of separating sludge by size. For example, the sludge separation unit 18 is a cyclone or a combination of a cyclone and a filter. The filter can remove sludge remaining in the first cleaning liquid Wa separated by the cyclone by filtration. A circulation path 15d is connected to the sludge separation unit 18 on the discharge side of the first cleaning liquid Wa. The other end of the circulation path 15 d is connected to the upstream pipe of the economizer 2.

  The schematic diagram of the collection part 19 is shown in FIG. The collection unit 19 includes an introduction path 19a, a discharge path 19b, a collection tank 19c, and a liquid feeding section 19d.

  The introduction path 19a has one end connected to the second cleaning liquid Wb discharge side of the sludge separation unit 18 and the other end connected to the collection tank 19c. The discharge path 19b has one end connected to the collection tank 19c and the other end connected to the circulation path 15d on the downstream side of the sludge separation unit 18 (the first cleaning liquid Wa discharge side). The introduction path 19a and the discharge path 19b may be installed at a position where the distance of the second cleaning liquid Wb flowing in the collection tank 19c becomes long, for example, on the wall surface facing the outer wall of the collection tank 19c.

  A liquid feeding unit 19d is installed in the middle of the discharge path 19b. The liquid feeding part 19d is means for sending the second cleaning liquid Wb 'that has come out to the discharge path to the circulation path 15d. For example, the liquid feeding unit 19d is a liquid feeding pump or the like.

  The collection tank 19c can store the second cleaning liquid Wb guided through the introduction path 19a. The collection tank 19c includes a collection means 19e that collects sludge in the second cleaning liquid Wb. When the sludge contains a magnetic material, for example, the collecting means 19e is a magnet. In FIG. 2, the electromagnetic filter 19e is installed in the bottom part of the collection tank 19c.

  As shown in FIG. 2, a partition plate 19f is installed on at least a part of the surface along the water surface below the water surface of the second cleaning liquid Wb of the collection tank 19c (the surface indicated by ▽) in the gravity direction. It is good to be. The partition plate 19f is installed with one end fixed to the wall surface of the collection tank 19c. The position of the partition plate 19f in the height direction in the gravity direction is between the main flow path region of the second cleaning liquid Wb passing through the collection tank 19c and the water surface of the second cleaning liquid Wb accommodated in the collection tank 19c. It is installed at a height position that divides in the direction of gravity. For the partition plate 19f, for example, a steel plate having a thickness capable of maintaining the shape can be used.

  Here, the main flow path region is, for example, a region centered on a straight line connecting the connection portion of the introduction path 19a and the connection portion of the discharge path 19b. In the present embodiment, in FIG. 2, a region formed between the height at which the partition plate 19f is installed and the upper surface of the electromagnetic filter 19e is defined as a main flow channel region.

  The hydrogen storage alloy in this embodiment is included in the microcapsule as described later.

  The partition plate 19f may be arranged such that the surface direction is along the water surface. At the height position where the partition plate 19f is installed, an area is provided between the partition plate 19f and the water surface (the surface that is indicated by ▽) to accommodate a predetermined amount of microcapsules that have floated on the water surface side. . The horizontal installation position of the partition plate 19f may be installed so as to cover at least the upper part on the side to which the discharge path 19b is connected. Accordingly, the hydrogen storage alloy encapsulated in the microcapsules flowing in from the introduction path 19a gathers lighter specific gravity than the cleaning liquid W in the space on the upper surface side in the gravitational direction than the partition plate 19f and recirculates from the discharge path 19b. Can be suppressed.

  In the collection tank 19c, the connection part of the discharge path 19b is provided at a height position higher than the middle between the water surface of the second cleaning liquid Wb and the upper surface of the electromagnetic filter 19e. Thereby, it can suppress that the sludge collected by the electromagnetic filter 19e recirculates from the discharge path 19b.

  The makeup water tank 13 contains makeup water. The makeup water is, for example, pure water that satisfies a predetermined water quality. The makeup water tank 13 is connected to the circulation path 15 (15a and 15b) by a makeup water supply path 20. In FIG. 1, the makeup water supply path 20 is branched into a first supply path 20a and a second supply path 20b on the way. The other end of the first supply path 20 a is connected to the circulation path 15 a on the upstream side of the steam heating unit 16. The other end of the second supply path 20 b is connected to the circulation path 15 b on the downstream side of the steam heating unit 16.

  The makeup water supply path 20 further includes a third supply path 20c. The third supply path 20 c is connected to the upstream pipe and the downstream pipe of the superheater 5 and the upstream pipe of the high-pressure feed water heater 1. As a result, water filling is performed on the non-cleaning system, and a pressurized water seal is provided so that the cleaning liquid W does not go upstream from the high-pressure feed water heater 1 and downstream from the superheater 5 to separate the economizer 2 from the gas-water separator. The cleaning liquid W can be circulated in the cleaning system between the container 4 and the container 4.

  The medicine injection part 14 is installed in the middle of the second supply path 20b. The medicine injection unit 14 includes an acid liquid tank (not shown) that stores an acidic chemical liquid for chemical cleaning, and injection means (not shown) that injects the acidic chemical liquid into the second supply path 20b. The acidic chemical solution is, for example, hydrochloric acid, citric acid, glycolic acid or the like. The pH of the cleaning liquid W is set to a predetermined value of 2 to 4 by injecting the acidic chemical liquid.

  The hydrogen storage alloy mixing unit 12 includes a hydrogen storage alloy tank 12a, a mixing path 12b, and mixing means (not shown).

  The hydrogen storage alloy tank 12a is connected to the second supply path 20b on the downstream side of the medicine injection part 14 through the mixing path 12b. The hydrogen storage alloy tank 12a is a water tank made of, for example, a steel plate, in order to inject a container containing the hydrogen storage alloy contained in the microcapsule, a water tank into which water of the same quality as makeup water is injected. It consists of a pump. The mixing means mixes the hydrogen storage alloy contained in the microcapsule with water in the water tank in advance and injects it from the mixing path 12b with a pump.

  Examples of hydrogen storage alloys using transition elements (Ti, Mn, Zr, Ni, etc.), alloys of rare earth elements and catalytic transition elements (La-Ni, Re-Ni, etc.), body-centered cubic crystals And intermetallic compounds (Ti-Fe system, V system, etc.) and alloys (Pd, Mg alloy system) that take in hydrogen between metal gaps. In the present embodiment, the hydrogen storage alloy is preferably non-magnetic or weakly magnetic for separation from sludge containing a magnetic material. In addition, by using a lightweight Mg alloy system, it is easy to make adjustments close to the specific gravity of the cleaning liquid W. However, the specific gravity can be adjusted by devising other hydrogen storage alloys to be encapsulated in microcapsules made of a material having a smaller specific gravity.

  The hydrogen storage alloy is encapsulated in microcapsules formed of a substance through which hydrogen can pass, and can be used in this state, and is preferably contained in the hydrogen storage alloy tank 12a. The substance used as the material of the microcapsule is, for example, a resin and has heat resistance to heat of at least about 100 ° C. The resin is, for example, Teflon (registered trademark), polyimide, or a mixture thereof, and can pass hydrogen by reducing the thickness or forming it in a porous shape. By encapsulating the hydrogen storage alloy in the microcapsule, the specific gravity can be adjusted in accordance with the specific gravity of the cleaning liquid W, and can be easily conveyed along with the flow of the cleaning liquid W. The hydrogen storage alloy has the property of becoming powdered due to embrittlement when repeated hydrogen storage and release, but even if the hydrogen storage alloy is powdered by encapsulating the hydrogen storage alloy in microcapsules, Stays in the microcapsule. For this reason, recovery from the cleaning liquid W is easy.

  The size of the microcapsule can pass without being captured by the filter provided in the middle of the cleaning system of the economizer 2 → the furnace wall tube 3 → the steam separator 4 → the circulation path 15 → the economizer 2; The diameter (φ) is 50 μm to 500 μm, preferably 100 μm to 300 μm. The thickness of the microcapsule is 10 μm or more and 250 μm or less, which allows hydrogen to pass through and can be contained and held even if the hydrogen storage alloy is powdered.

  The specific gravity of the microcapsules containing the hydrogen storage alloy is adjusted to a predetermined range that is equivalent to the specific gravity of the cleaning liquid W (about 1 in the present embodiment). The specific gravity can be adjusted by the material composition or thickness of the macrocapsule. The predetermined range is set based on the specific gravity of the cleaning liquid W. For example, the predetermined range is a specific gravity of the cleaning liquid ± 10%.

  Furthermore, the specific gravity of the microcapsules containing the hydrogen storage alloy is adjusted so that the microcapsules float on the cleaning liquid when the hydrogen storage alloy stores a predetermined amount or more of hydrogen. The predetermined amount is set so that efficient operation can be performed when the reaction rate starts to decrease with hydrogen storage in the surface layer of the hydrogen storage alloy. In this embodiment, the stoichiometric hydrogen storage capacity calculated from the amount of the hydrogen storage alloy is 30% to 50%.

The cleaning apparatus according to the present embodiment further includes a regeneration unit 21 in order to discharge the stored hydrogen from the microcapsules containing the hydrogen storage alloy so that the microcapsules containing the hydrogen storage alloy can be reused. May be.
FIG. 3 shows a schematic diagram of the reproducing unit 21. The regeneration unit 21 includes a recovery unit 21a, a regeneration tank 21b, and a heating unit 21c.

  The collection means 21a connects the collection tank 19c and the regeneration tank 21b, and collects the microcapsules containing the hydrogen storage alloy contained in the collection tank 19c together with the cleaning liquid Wb. The collection means 21a is a tubular member or the like. The recovery means 21a may be provided with a pump or the like (not shown) that sucks up microcapsules containing cleaning liquid and a hydrogen storage alloy, or may be siphoned using gravity. One end of the tubular member is disposed in the collection tank 19c so as to be sucked up from a position below the water surface of the cleaning liquid and a position slightly deeper than the water surface.

  The regeneration tank 21b accommodates the microcapsules containing the cleaning liquid Wb and the hydrogen storage alloy collected by the collecting means 21a. A stirring device 21d is installed in the regeneration tank 21b. The stirring device 21d can stir the solution stored in the regeneration tank 21b.

  The regeneration tank 21b includes an exhaust port 21e at the upper part in the direction of gravity. In FIG. 3, a decompression pump 21f is installed at the exhaust port 21e. An exhaust path 21g (solid line) for discharging the hydrogen gas discharged from the hydrogen storage alloy to the outside of the system or a reuse path 21h (broken line) for reusing the hydrogen gas can be connected to the tip of the decompression pump 21f.

  The regeneration tank 21b has a drain port 21i at the bottom. A filter 21j is installed at the drain port 21i. The filter 21j is for preventing the microcapsule from coming out of the drain port 21i. One end of a tubular member 21k is connected to the drain port 21i. The other end of the tubular member 21k may be connected to a storage tank 21l that stores unnecessary cleaning liquid discharged. The tubular member 21k may include opening / closing means (not shown) such as a valve for opening and closing the flow path.

  The heating means 21c is installed in the regeneration tank so as to heat the cleaning liquid Wb in the regeneration tank 21b. The heating means heats the cleaning liquid Wb in the regeneration tank 21b and raises the temperature to a temperature at which hydrogen can be desorbed. In the Mg alloy-based hydrogen storage alloy of this embodiment, the temperature at which hydrogen can be desorbed is about 85 ° C. to 95 ° C., and the pressure in the regeneration tank 21b is reduced by the decompression pump 21f, thereby storing the hydrogen. Hydrogen desorption from the alloy is promoted. The heating means 21c is, for example, heating with water vapor supplied from a burner or an adjacent plant. As the fuel for the burner, hydrogen desorbed from the hydrogen storage alloy may be used as part of the fuel.

  Next, a cleaning method using the cleaning apparatus according to the present embodiment will be described. The cleaning method of the present embodiment is, for example, a process of using a fire such as welding in the periphery, such as a process of laying an in-furnace scaffold or a process of constructing equipment other than the equipment to be cleaned, during periodic inspection of a thermal power generation system. Conducted in parallel during the period.

  First, the cleaning device 10 is installed in a device to be cleaned (not necessary in the case of permanent installation). Supply water is supplied from the makeup water tank 13 to the non-cleaning system (upstream and downstream piping of the superheater 5 and upstream piping of the high-pressure feed water heater 1) using a pump, and the cleaning liquid is mixed into the non-cleaning system. Seal with pressurized water to prevent it.

The makeup water S _a and the makeup water S _b are supplied from the makeup water tank 13 to the upstream side and the downstream side of the steam heating unit 16, respectively.

The makeup water _Sa is supplied to the upstream side of the steam heating unit 16 through the first supply path 20a. The makeup water S _a lead to the steam heating unit 16 is heated to a predetermined temperature. The predetermined temperature is about 60 ° C to 80 ° C.

The makeup water _Sb is supplied to the downstream side of the steam heating unit 16 through the second supply path 20b. The makeup water S _b, injecting the acidic chemical liquid from the middle medicine injecting portion 14 of the second supply path 20b. The acidic chemical solution may be additionally injected as appropriate so that the cleaning solution can maintain a predetermined pH. More makeup water S _b, incorporating a predetermined amount of the hydrogen storage metal from the hydrogen storage alloy aeration unit 12 in the middle of the second supply path 20b. On the downstream side of the steam heating unit 16, the make-up water _Sa and the make-up water _Sb are merged to obtain an acidic cleaning liquid W mixed with a hydrogen storage metal.

For example, the cleaning liquid W has a pH of 2 to 4 and a temperature of 60 ° C. to 90 ° C. The replenishing water S _a , the replenishing water S _b, and the acidic chemical liquid are supplied in such amounts that the cleaning liquid W satisfies the above conditions. The circulation flow rate of the cleaning liquid W is preferably set such that the cleaning liquid W spreads without staying in the cleaning system and the supply of the cleaning liquid W is maintained in the reaction region with the scale.

Hydrogen storage metal is mixed into the makeup water S _b in a state where hydrogen is contained in the resin of the microcapsules passes. The mixing amount of the hydrogen storage alloy and the filling amount into the microcapsules may be set based on the amount of hydrogen expected to be generated in the cleaning system. A microcapsule containing a hydrogen storage alloy is manufactured, for example, by pressing and solidifying a predetermined amount of a hydrogen storage alloy into a spherical shape of a predetermined size (φ) from 50 μm to 500 μm, and depositing a resin around it and coating it. it can.

The cleaning liquid W is sent to the sludge separation unit 18 by the liquid feeding unit 17. Hereinafter, the sludge separation unit 18 will be described as a cyclone. Subjecting the washing liquid W into the cyclone, it is separated into a first washing solution W _a free of sludge, and a second washing solution W _b containing sludge. Most of the microcapsules containing a hydrogen storage alloy are intended to be included in the second washing solution W _b. The cyclone separation conditions are set such as the rotation of water flow so that the microcapsules containing the hydrogen storage alloy and the sludge coarser than the microcapsules can be separated. Microcapsules containing a hydrogen storage alloy need not be completely separated from coarse sludge. The second washing solution W _b, may include microcapsules containing a hydrogen storage alloy.

A first washing solution _{W a} feed to the circulation path 15d, is circulated to the economizer 2.

The second cleaning liquid _Wb is introduced into the collection tank 19c through the introduction path 19a. Then, it is sent to the circulation path 15d connected from the discharge path 19b to the economizer 2 by the liquid feeding section 19d, and is mixed with the circulation of the cleaning liquid.

Within the collection tank 19c, sludge S in the second washing solution W _b is trapped attracted to 19e (electromagnetic filter is magnet) collecting means, containing the hydrogen-absorbing alloy having a hydrogen storage capacity The microcapsule P returns to the cleaning system. The collection tank 19c is preferably in a turbulent state. Thereby, the sludge containing a magnetic body is sufficiently supplemented by the electromagnetic filter 19e which is a magnet.

  The microcapsule T containing the hydrogen storage alloy in which a predetermined amount or more of hydrogen is stored floats in the upper part of the gravity direction in the collection tank 19c. The partition plate 19f provided in the collection tank 19c has a specific gravity smaller than the specific gravity of the cleaning liquid W, the microcapsule T in which the hydrogen storage alloy storing the hydrogen floating on the water surface is contained, and the water is transported and moved by the water flow. A partition plate 19f partitions the microcapsule P containing the hydrogen storage alloy. This prevents the microcapsules T enclosing the hydrogen storage alloy in which the hydrogen storage capacity has been decreased from being circulated to the cleaning system.

  After completion of the cleaning, the microcapsules (P, T) containing the hydrogen storage alloy together with the cleaning liquid W are led out to the collection tank 19c and recovered to the regeneration tank 21b. The sludge S is dissolved in the acidic cleaning liquid by eliminating the magnetic force of the electromagnetic filter 19e. If the sludge S remains undissolved, the sludge S may be recovered in the regeneration tank 21b after performing a step of dissolving in the collection tank 19c over time.

  In the regeneration tank 21b, the recovered cleaning liquid and the microcapsules (P, T) are heated to a temperature at which hydrogen can be desorbed by the heating means 21c while stirring. The hydrogen stored in the hydrogen storage alloy is desorbed from the hydrogen storage alloy by heating and released out of the microcapsule. Thereby, the hydrogen storage ability of the microcapsules enclosing the hydrogen storage alloy is regenerated.

  The inside of the regeneration tank 21b is set to an atmospheric pressure to reduced pressure environment. By operating the decompression pump 21f and exhausting the inside of the regeneration tank, hydrogen gas is discharged out of the system. By setting the inside of the regeneration tank 21b to a reduced pressure environment, the hydrogen stored in the hydrogen storage alloy can promote the desorption from the hydrogen storage alloy. Here, the hydrogen gas that has been separated and exhausted may be reused as part of the fuel of the heating means 21c.

  After regenerating the microcapsule T containing the hydrogen storage alloy containing hydrogen, the drainage port 21i is opened as necessary, and the sludge S dissolves and the cleaning liquid that is no longer needed is discharged to the storage tank. to recover. A filter 21j is installed at the drain port 21i so that the microcapsules do not exit from the drain port 21i.

  In this embodiment, by mixing microcapsules containing a hydrogen storage alloy in the cleaning liquid W, hydrogen generated at various points in the cleaning system can be recovered. Since the microcapsules enclosing the hydrogen storage alloy have the specific gravity equivalent to that of the cleaning liquid W, the microcapsules are easily transported by the water flow of the cleaning liquid, so that the recovery efficiency of hydrogen generated at various points in the cleaning system is improved.

Here, a setting example of the mixing amount of the hydrogen storage alloy and the filling amount into the microcapsules in the present embodiment will be shown. Magnesium hydroxide (Mg (OH) ₂ ) is used as the hydrogen storage alloy. Mg (OH) ₂ is a light, inexpensive and chemically stable substance, and can release hydrogen at 100 ° C. or lower.

The hydrogen storage reaction of Mg (OH) ₂ is shown in Formula (1).
Mg (OH) ₂ + 2H ₂ → MgH ₂ + 2H ₂ O + heat generation (1)

Molecular weight: Mg (OH) ₂ = 58
Specific gravity of Mg (OH) ₂ : 2.36 g / cm ³
Specific gravity of MgH ₂ : 1.7 g / cm ³

Let V m ^{3 be the} amount of hydrogen gas generated during the cleaning period of the large boiler. Mg (OH) ₂ required to occlude V m ³ hydrogen gas is as follows.
Hydrogen gas: V [m ³ ] / (22.4 × 10 ⁻³ ) × (58 × 10 ⁻³ /2)=1.3×V [kg]

The amount of hydrogen storage alloy that can be filled into a 100 μm diameter capsule with a specific gravity of 1.0 is as follows.
(4 / 3π100 ³ × 10 ⁻¹⁸ ) × (1 × 10 ⁻³ ) = 4.2 × 10 ⁻¹⁵
[Kg / capsule]

By the way, the filling rate of the amount of hydrogen storage alloy filled in the capsule of 100 μm in diameter is
4.2 × 10 ⁻¹⁵ [kg / capsule] ÷ (specific gravity: 2.36 × 10 ⁻³ ) ÷ (4 / 3π100 ³ × 10 ⁻¹⁸ ) = 42 [%]

Assuming that the effective storage efficiency of the microcapsules containing the hydrogen storage alloy is 10%, the number of microcapsules containing the hydrogen storage alloy to be supplied to the device to be cleaned is as follows.
Hydrogen storage alloy (1.3 × V) [kg] ÷ (4.2 × 10 ⁻¹⁵ [kg / capsule]) / storage efficiency 10% = 3.1 × V × 10 ¹⁵ [pieces]

Hydrogen gas amount generated from the above, during the washout period with large boilers: If V m ³ is to 10 to 100 m ^3, by supplying the microcapsules containing about 10 ¹⁷ of the hydrogen storage alloy to be cleaned equipment The hydrogen generated in the cleaning system can be occluded and recovered.

The volume of the microcapsule containing 10 ¹⁷ hydrogen storage alloys is as follows.
(4 / 3π100 ³ × 10 ⁻¹⁸ ) × 10 ¹⁷ = 0.4 [m ³ ]

Therefore, the collection tank 19c can cope with a capacity of 1 m ³ or more.

The microcapsules encapsulating the hydrogen storage alloy have a specific gravity which decreases as described below due to the storage of hydrogen.
1.0 × (specific gravity of MgH ₂ : 1.7 / specific gravity of Mg (OH) ₂ : 2.36) ≈0.7

[Second Embodiment]
The present embodiment is characterized in that microcapsules containing a hydrogen storage alloy having a predetermined range of specific gravity of the cleaning liquid and a plurality of different specific gravity are mixed. The configuration without description is the same as in the first embodiment.

  The microcapsules enclosing hydrogen storage alloys having different specific gravities are intentionally adjusted as such, and do not include differences in specific gravities caused by variations during adjustment. The variation at the time of adjustment is about ± 5%.

  The hydrogen storage alloy tank 12a accommodates microcapsules containing hydrogen storage alloys having different specific gravities. The specific gravity of the microcapsules containing the hydrogen storage alloy is selected from a plurality of predetermined ranges based on the specific gravity of the cleaning liquid (specific gravity: about 1) as in the first embodiment.

  For example, the hydrogen storage alloy tank 12a has microcapsules containing a plurality of hydrogen storage alloys in a predetermined range. As a plurality of predetermined ranges, for example, the specific gravity exceeds −5% and within −10%, the specific gravity within ± 5%, the specific gravity exceeds + 5% and within + 10% with respect to the cleaning liquid Can be exemplified. In this case, the first microcapsule (hydrogen storage alloy inclusion) adjusted to a specific gravity (0.9 to less than 0.95) smaller than the cleaning liquid (specific gravity: about 1) and the specific gravity (0.95) equivalent to the cleaning liquid The second microcapsule (hydrogen storage alloy inclusion) adjusted to 1.05 or less as described above, and the third microcapsule (hydrogen storage alloy inclusion adjusted to a specific gravity greater than 1.05 and 1.1 or less) than the cleaning liquid. ). The first microcapsule, the second microcapsule, and the third microcapsule may be accommodated in separate hydrogen storage tanks for grasping the input amount. In addition, the first microcapsule, the second microcapsule, and the third microcapsule may be colored differently so that they can be easily distinguished from the appearance.

  Since the specific gravity of the first microcapsule is smaller than that of the cleaning liquid, the first microcapsule tends to exist in the upper part in the gravity direction in the water flow of the cleaning liquid. The second microcapsules tend to exist evenly in the water flow of the cleaning liquid, and the third microcapsules tend to exist in the lower part of the gravity direction in the water flow of the cleaning liquid.

  By mixing microcapsules containing hydrogen storage alloys having different specific gravities, the opportunity to store hydrogen generated at various locations in the cleaning system increases, so that hydrogen efficiency is improved. The second microcapsules occlude hydrogen generated at various places in the early stage of chemical cleaning. In addition, the third microcapsule has a specific gravity that decreases after occlusion of some hydrogen and becomes equivalent to the cleaning liquid (specific gravity: about 1), and therefore can be more easily transported by the water flow. Thereby, the opportunity to occlude hydrogen further increases in the downstream where the cleaning liquid circulates, which is efficient.

[Third Embodiment]
This embodiment is characterized in that, during cleaning, a microcapsule having a specific gravity smaller than that of the cleaning liquid and encapsulating the hydrogen storage alloy floating on the water surface of the cleaning liquid is collected from the cleaning target device. The configuration without description is the same as that of the first embodiment or the second embodiment.

  The cleaning device according to the present embodiment includes suction means. The suction means is connected to a configuration in which the cleaning liquid in the cleaning system flows in a direction penetrating the water surface. In this embodiment, the configuration is the steam separator 4. The steam-water separator 4 has a configuration in which the cleaning liquid flows from the upper part in the gravity direction, the cleaning liquid flows out from the lower part in the gravity direction, and the water surface exists inside.

  FIG. 4 is a schematic diagram for explaining the suction means. In FIG. 4, for simplification of the drawing, configurations other than the furnace wall tube 3, which is a cleaning target device, the liquid feeding unit 17 provided in the circulation path 15, and the suction means 22 are omitted.

The suction means 22 includes a suction path 22a, a liquid feeding part 22b, and a return path 22c.
One end of the suction path 22a is connected to the steam separator 4 and the other end is connected to the liquid feeding part 22b. The suction path 22a is a tubular member. The tubular member can be inserted from a permanent air vent portion or the like provided at the upper part of the steam / water separator 4 in the direction of gravity. One end of the inserted tubular member is disposed below the surface of the cleaning liquid stored in the steam separator 4.

  The liquid feeding part 22b is a liquid feeding pump or the like. One end of the return path 22 c is connected to the outlet side of the liquid feeding part 22 b, and the other end is connected to the downstream pipe of the steam separator 4. A branch path 22d may be provided in the middle of the return path 22c.

  When the cleaning liquid W including the microcapsules containing the hydrogen storage alloy is circulated in the cleaning system, the hydrogen storage alloy stores hydrogen and the specific gravity decreases. If the circulation of the cleaning liquid W is continued, the microcapsules T containing the hydrogen storage alloy having a reduced specific gravity with hydrogen stored in the water surface in the steam separator 4 may float and accumulate. If the microcapsules containing the hydrogen storage alloy are accumulated on the water surface, the flow path of the cleaning liquid may be blocked and clogged, or the cleaning liquid may not flow easily.

  In this embodiment, when the microcapsules containing the hydrogen storage alloy are collected on the water surface in the steam separator 4, the microcapsules containing the stored hydrogen storage alloy are extracted. The sampling is preferably performed at the timing when the chemical cleaning process ends when half or more of the total chemical cleaning time has elapsed. The extraction amount is preferably such that the hydrogen storage alloy accumulated on the water surface in the steam separator 4 is contained and more than half of the microcapsules so that the cleaning liquid flowing into the steam separator 4 is not clogged. .

  Although the extracted hydrogen storage alloy is encapsulated and the microcapsules store hydrogen, they still have the capacity to store hydrogen. Therefore, the microcapsules have a capacity to store hydrogen. ). The microcapsule containing the extracted hydrogen storage alloy may be discharged out of the system from the branch path 22d.

  By removing the microcapsules containing the hydrogen storage alloy floating on the water surface of the cleaning liquid, the cleaning liquid that has flowed into the steam separator 4 can escape to the lower part in the direction of gravity without clogging, and the hydrogen generated by chemical cleaning can be removed. It is possible to avoid a reduction in recovery efficiency in the steam separator 4.

In the collection tank 19c, the microcapsules containing most of the hydrogen storage alloy are separated by the sludge separation unit 18. Therefore, microcapsules amount of hydrogen storage alloy contained in the second cleaning liquid W _b is contained is small. In contrast, the microcapsules the amount of encapsulating a hydrogen storage alloy in the cleaning liquid flowing into the steam-water separator 4 is larger by the amount contained in the first washing solution W _a.

  Therefore, there is a possibility that the microcapsule T containing the hydrogen storage alloy floating on the water surface in the steam separator 4 is mixed with the microcapsule P ′ containing the hydrogen storage alloy whose hydrogen storage amount is less than the predetermined amount. There is. By returning the microcapsules P ′ enclosing the extracted hydrogen storage alloy into the cleaning system, the microcapsules P ′ enclosing the hydrogen storage alloy whose hydrogen storage amount is less than a predetermined amount can be used without waste.

1 High-pressure feed water heater 2 Carbon-saving device 3 Furnace wall pipe (equipment to be cleaned)
4 Steam separator (equipment in cleaning system)
DESCRIPTION OF SYMBOLS 5 Superheater 10 Cleaning apparatus 11 Circulation part 12 Hydrogen storage alloy mixing part 12a Hydrogen storage alloy tank 12b Mixing path 13 Makeup water tank 14 Medicine injection part 15, 15a, 15b, 15c, 15d Circulation path 16 Steam heating part 17 Liquid sending part 18 Sludge separation part 19 Collection part 19a Introduction path 19b Discharge path 19c Collection tank 19d Liquid feeding part 19e Electromagnetic filter (collection means)
19f Partition plate 20 Supply water supply path 20a First supply path 20b Second supply path 21 Regeneration unit 21a Recovery means 21b Regeneration tank 21c Heating means 21d Stirring device 21e Exhaust port 21f Decompression pump 21g Exhaust path 21h Reuse path 21i Drainage port 21j Filter 21k Tubular member 21l Storage tank 22 Suction means 22a Suction path 22b Liquid feeding section 22c Return path 22d Branch path

Claims (19)

  An acidic cleaning liquid mixed with a hydrogen storage alloy is supplied to the device to be cleaned, the scale attached to the device to be cleaned is removed, and at least a part of the hydrogen generated in the device to be cleaned is stored in the hydrogen storage device. Cleaning method with alloy recovery.   The cleaning method according to claim 1, wherein the hydrogen storage alloy encapsulated in a microcapsule formed of a substance through which hydrogen can pass is mixed in the cleaning liquid.   The cleaning method according to claim 2, wherein the specific gravity of the microcapsules containing the hydrogen storage alloy is adjusted to a predetermined range that is equivalent to the specific gravity of the cleaning liquid, and is mixed into the cleaning liquid.   The cleaning method according to claim 3, wherein the microcapsules containing the hydrogen storage alloy are adjusted so as to be in a predetermined range of a plurality of different specific gravities, and are mixed in the cleaning liquid. Discharging the cleaning liquid from the device to be cleaned;
The cleaning method according to any one of claims 2 to 4, wherein the discharged cleaning liquid is supplied to a collecting unit to collect sludge in the cleaning liquid.   The collection portion includes an introduction portion and a discharge portion for the cleaning liquid, the main flow channel region of the cleaning liquid passing through a region including a region centered on a straight line connecting the introduction portion and the discharge portion, and the collection portion. The cleaning method according to claim 5, wherein a partition plate is provided so as to cover at least an upper part in the gravity direction of the discharge part between the cleaning liquid and the water surface accommodated in the part.   The cleaning method according to claim 3 or 4, wherein at least a part of the microcapsules in which the specific gravity is smaller than water and the hydrogen storage alloy floating on the water surface of the cleaning liquid is included is recovered from the cleaning target device.   The microcapsule in which the hydrogen storage alloy having a specific gravity smaller than the predetermined range is heated to a predetermined temperature, and the hydrogen adsorbed on the hydrogen storage alloy is desorbed and regenerated. Cleaning method.   The cleaning method according to claim 3 or 4, wherein at least a part of the microcapsules having a specific gravity smaller than water and enclosing the hydrogen storage alloy floating on the surface of the cleaning liquid is extracted from the cleaning target device. A circulating part for circulating acidic cleaning liquid to the equipment to be cleaned;
A hydrogen storage alloy tank for storing a hydrogen storage alloy, and a hydrogen storage alloy mixing portion for mixing the hydrogen storage alloy into the cleaning liquid;
Cleaning device equipped with.   The cleaning apparatus according to claim 10, wherein the hydrogen storage alloy is encapsulated in a microcapsule formed of a substance through which hydrogen can pass.   The cleaning apparatus according to claim 11, wherein the specific gravity of the microcapsules containing the hydrogen storage alloy is a value within a predetermined range that is equivalent to the specific gravity of the cleaning liquid.   The cleaning apparatus according to claim 12, wherein the hydrogen storage alloy tank contains a plurality of microcapsules enclosing the hydrogen storage alloy in a predetermined time range having different specific gravities.   The cleaning apparatus according to any one of claims 10 to 13, wherein the circulation unit includes a collection unit, and the collection unit includes a collection unit that collects sludge in the cleaning liquid.   The cleaning apparatus according to claim 14, wherein the collecting means is a magnet. The collection unit includes an introduction unit and a discharge unit for the cleaning liquid, and a partition plate,
The partition plate is provided between a main flow path region of the cleaning liquid that passes through a region including a region centering on a straight line connecting the introduction portion and the discharge portion, and a water surface of the cleaning liquid accommodated in the collection portion. The cleaning device according to claim 14 or 15, wherein the cleaning device is installed at a position so as to cover at least an upper part in the gravity direction of the discharge unit.   15. The recovery unit according to claim 12 or 14, further comprising a recovery unit that is connected to a device in the cleaning system and has a specific gravity smaller than that of water and absorbs the microcapsules enclosing the hydrogen storage alloy floating on the water surface of the cleaning liquid. Cleaning equipment. The reproduction unit further includes a reproduction unit,
A collecting means connected to the collecting section and collecting the microcapsules enclosing the cleaning liquid and the hydrogen storage alloy contained in the collecting section;
A regeneration tank containing microcapsules containing the collected cleaning liquid and the hydrogen storage alloy;
Heating means for heating the microcapsules containing the hydrogen storage alloy collected in the regeneration tank to a temperature at which hydrogen can be desorbed;
With
The cleaning device according to any one of claims 14 to 16, wherein the regeneration tank includes an exhaust port for the detached hydrogen. 14. The apparatus according to claim 12, further comprising an extraction unit that is connected to a device in the cleaning system and has a specific gravity smaller than that of water and extracts a microcapsule containing the hydrogen storage alloy floating on the water surface of the cleaning liquid. Cleaning equipment.

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