JP7013258B2 - Denitration catalyst regeneration method and denitration catalyst regeneration system - Google Patents

Description

The present invention relates to a denitration catalyst regeneration method and a denitration catalyst regeneration system, and more particularly to a denitration catalyst regeneration method for a coal-fired boiler and a denitration catalyst regeneration system.

Equipment for burning fuels such as fossil fuels and biomass is equipped with denitration equipment for removing nitrogen oxides contained in exhaust gas generated by burning the fuel. Such denitration equipment is equipped with a denitration catalyst that promotes the removal of nitrogen oxides. Since the performance of the denitration catalyst deteriorates due to use, in the denitration equipment equipped with the denitration catalyst, the denitration catalyst is replaced or added at the time of maintenance. It has also been proposed to perform a regeneration process to restore the performance of the denitration catalyst in order to reuse it.

As such a regeneration treatment, a denitration catalyst whose activity has been reduced by a toxic substance of silica, alumina, or calcium sulfate is prewashed with water, soaked in water, and then a mixed solution of an organic acid and fluoride is used for the same substance. A method and an apparatus for cleaning and removing calcium sulfate at room temperature are known (Patent Document 1). Further, a method and a system for removing deposits such as calcium adhering to the surface of the catalyst by pre-washing the denitration catalyst with water and then immersing the catalyst in a chemical solution containing a fluorine compound and an inorganic acid are known (). Patent Document 2).

Japanese Patent Application Laid-Open No. 2011-31237 International Publication No. 2017/010402

In the above-mentioned example, even if the regeneration treatment is performed, the coarse particles clogged in the gas passage holes of the denitration catalyst cannot be sufficiently removed. In addition, there is a possibility that a separate measure for removing such coarse particles may be required. Further, in the above-mentioned example, although pre-washing with water and then chemical washing with a fluorine compound and an acid, deposits such as coarse particles cannot be effectively removed, and the effect of catalyst regeneration is reduced. One of the reasons is considered to be that the catalyst is hydrated by pre-washing with water, and the effects of the fluorine compound and the acid are reduced. As a countermeasure, it is possible to increase the concentration of the fluorine compound, but such a countermeasure may affect the components of the catalyst. Further, when the used denitration catalyst is washed with water and then dried again, the deposits accumulated in the gas passage holes of the denitration catalyst are aggregated and cannot be removed as coarse particles.

An object of the present invention is to provide a denitration catalyst regeneration method and a denitration catalyst regeneration system capable of removing toxic substances adhering to the denitration catalyst and removing coarse particles clogged in gas passage holes of the denitration catalyst. ..

In order to achieve the above object, in the method for regenerating the denitration catalyst according to one aspect of the present invention, the denitration catalyst is immersed in a chemical solution containing a fluorine compound, an inorganic acid and a surfactant in a dry state, and the chemical solution is washed. Includes at least a cleaning step.

Further, in the method for regenerating the denitration catalyst according to one aspect of the present invention, the denitration catalyst taken out from the chemical solution is immersed in water in a vacuum drawing tank, the tank is sealed, and the air in the tank is sucked for finish cleaning. Including at least steps.

Further, in the method for regenerating the denitration catalyst according to one aspect of the present invention, the fluorine compound is ammonium hydrogen fluoride, the amount of the fluorine compound is 1 to 10% by mass with respect to the entire chemical solution, and the inorganic acid. Is an amount added so that the pH value of the chemical solution is in the range of pH 1 to 6, and the amount of the surfactant is 0.001 to 10% by mass with respect to the entire chemical solution.

Further, in the method for regenerating the denitration catalyst according to one aspect of the present invention, in the finish cleaning step, after cleaning in the vacuum drawing tank, the denitration catalyst taken out from the tank is used as water or sulfamic acid-containing water as a cleaning liquid. Further includes a finishing wash step to wash.

Further, in the method for regenerating the denitration catalyst according to one aspect of the present invention, in the chemical solution cleaning step, cleaning is performed by directly immersing the denitration catalyst removed from the denitration facility in the chemical solution in the chemical washing tank.

Further, in the method for regenerating the denitration catalyst according to one aspect of the present invention, the surfactant is a nonionic surfactant containing polyoxyethylene polyoxypropylene glycol, a polyoxyethylene derivative or a polyalkylene glycol derivative as a main component. Alternatively, it is an anionic surfactant containing a polyoxyalkylene alkyl ether phosphoric acid ester as a main component.

Further, in the method for regenerating the denitration catalyst according to one aspect of the present invention, the fluorine compound is ammonium hydrogenfluoride, the inorganic acid is sulfamic acid, and the surfactant is mainly polyoxyethylene polyoxypropylene glycol. It is a nonionic surfactant as an ingredient.

Further, in the method for regenerating the denitration catalyst according to one aspect of the present invention, the chemical solution is repeatedly used in the chemical solution washing step.

In order to achieve the above object, the denitration catalyst regeneration system according to one aspect of the present invention is such that the denitration catalyst is immersed in a chemical solution containing a fluorine compound, an inorganic acid and a surfactant in a dry state and washed with the chemical solution. It is provided with at least a chemical solution cleaning unit configured in.

Further, in the denitration catalyst regeneration system according to one aspect of the present invention, the denitration catalyst taken out from the chemical solution is immersed in water in a vacuum drawing tank, the tank is sealed, and the air in the tank is sucked. Further provided with a configured evacuation tank.

Further, in the denitration catalyst regeneration system according to one aspect of the present invention, the fluorine compound is ammonium hydrogen fluoride, the amount thereof is 1 to 10% by mass with respect to the entire chemical solution, and the amount of the inorganic acid is 1. The amount is added so that the pH value of the chemical solution is in the range of pH 1 to 6, and the amount of the surfactant is 0.001 to 10% by mass with respect to the entire chemical solution.

Further, the denitration catalyst regeneration system according to one aspect of the present invention further includes a finishing water washing tank in which the denitration catalyst taken out from the vacuum drawing tank is finished and washed with water or sulfamic acid-containing water as a finishing water washing liquid.

Further, in the denitration catalyst regeneration system according to one aspect of the present invention, the chemical cleaning unit performs cleaning by directly immersing the denitration catalyst removed from the denitration equipment in the chemical in the chemical washing tank. It is configured.

INDUSTRIAL APPLICABILITY According to the present invention, there is provided a denitration catalyst regeneration method and a denitration catalyst regeneration system capable of removing toxic substances adhering to the denitration catalyst and removing coarse particles clogged in gas passage holes of the denitration catalyst.

FIG. 1 is a schematic diagram showing a schematic configuration of a denitration catalyst regeneration system according to the first embodiment. FIG. 2 is a flowchart showing an example of a method for regenerating the denitration catalyst according to the first embodiment. FIG. 3 is a schematic diagram showing a schematic configuration of a denitration catalyst regeneration system according to a second embodiment. FIG. 4 is a flowchart showing an example of a method for regenerating the denitration catalyst according to the second embodiment. FIG. 5 is a graph showing the measurement results of the clogging rate of the denitration catalyst according to the embodiment. FIG. 6 is a graph showing the calculation result of the clogging removal rate of the denitration catalyst according to the embodiment. FIG. 7 is a graph showing the measurement results of the denitration reaction rate constant ratio of the denitration catalyst according to the embodiment. FIG. 8 is a graph showing the measurement results of the silica elution amount of the denitration catalyst according to the example.

Hereinafter, embodiments of the denitration catalyst regeneration method and the denitration catalyst regeneration system according to the present invention will be described in detail with reference to the accompanying drawings. The present invention is not limited to these embodiments. The attached drawings are diagrams for explaining the outline of the embodiment, and some of the attached devices are omitted. Further, when there are a plurality of embodiments, the technical scope of the present invention also includes configurations in which the embodiments are combined or partially replaced.

1. 1. First Embodiment 1.1. Regeneration system With reference to FIG. 1, the regeneration system of the denitration catalyst according to the first embodiment will be described. As shown in FIG. 1, the denitration catalyst regeneration system 100 includes a chemical solution cleaning unit 102, a finish cleaning unit 104, and a drying unit 106, and is configured to execute a regeneration process for recovering the denitration performance of the denitration catalyst. Has been done.

The denitration catalyst to be regenerated is, for example, silicon (Si) such as silica (SiO ₂ ), aluminum (Al), calcium (Ca), phosphorus (P), and arsenic (As) generated in a coal-fired boiler. ), Sodium (Na), potassium (K) and other toxic substances are used to denitrify exhaust gas, and the denitration performance is reduced (hereinafter, also referred to as used denitration catalyst). Such a denitration catalyst is, for example, a catalyst having a lattice-like (honeycomb-like) shape, a plate-like shape, a corrugated-like shape, or the like having at least one exhaust gas passage hole (hereinafter, also referred to as a gas passage hole). A carrier such as titanium (TiO ₂ ) is supported with at least one active ingredient selected from the group consisting of vanadium (V), tungsten (W) and molybdenum (Mо). Further, such a denitration catalyst is subject to regeneration treatment in a dry state.

The dry state described in the present specification is not limited to an absolutely dry state containing no water, but also includes a state in which water in the air is adsorbed. This is because catalysts such as denitration catalysts have small pores, and moisture in the air is adsorbed by the catalyst even if they are left indoors. The catalyst left under high humidity conditions becomes a wet state, but is included in the dry state of the present invention. It also includes a state in which the catalyst is dried after washing with water. The dry state described in the present specification is not limited to such a completely dry state, and the denitration catalyst is not subjected to a treatment for cleaning with water after the denitration catalyst is taken out from the denitration facility and the apparatus. It means a state. Examples of such a treatment include a cleaning treatment such as a pre-washing in which the catalyst is immersed in water or the catalyst is washed away with water. Further, the regeneration treatment in a dry state described in the present specification means that after the denitration catalyst is taken out from the denitration equipment and the apparatus, the denitration catalyst is directly washed with a chemical without performing a cleaning treatment such as pre-washing. It is intended to perform a chemical solution cleaning process by immersing the catalyst in a chemical solution in a tank, and to perform a chemical solution cleaning process after the catalyst is dried again after the cleaning process. Therefore, dust removal treatment such as air blow can be performed on the denitration catalyst in the denitration facility and after the denitration catalyst is taken out from the apparatus and before the chemical solution cleaning is performed.

The chemical solution cleaning unit 102 includes at least a chemical washing tank for cleaning the denitration catalyst and a mechanism for supplying the chemical solution into the chemical washing tank. The chemical washing tank is a container that is larger than the denitration catalyst to be regenerated and can store the chemical liquid. The chemical washing unit 102 is configured to put a dry denitration catalyst into the chemical washing tank in which the chemical solution is stored, and to immerse the denitration catalyst in the chemical solution. By immersing the denitration catalyst in the chemical solution, the chemical washing unit 102 elutes the toxic substance such as sparingly soluble silica from the denitration catalyst while suppressing the elution of active components such as vanadium from the denitration catalyst. At the same time, the particles clogged inside the denitration catalyst, particularly the coarse particles clogged in the exhaust gas passage holes, are dissolved to reduce the particle size. As the chemical solution cleaning unit 102, a device having a shower nozzle or the like, applying the chemical solution to the denitration catalyst, and immersing the chemical solution in the denitration catalyst can also be used. As used herein, the term "coarse particles" are intended to be particles having a diameter substantially equal to that of the gas passage hole of the denitration catalyst, for example, particles having a diameter substantially equal to that of the honeycomb hole of the denitration catalyst having a honeycomb shape. There is. The diameter of the coarse particles is, for example, about 5.0 mm, and it can be inferred that they are formed mainly containing silica, aluminum, and the like.

The finish cleaning unit 104 includes at least a vacuum drawing tank having a water tank for cleaning the denitration catalyst, a mechanism for supplying water into the water tank, and a vacuum pump for sucking air in the water tank. The evacuation tank is larger than the denitration catalyst to be regenerated, and is a container that can store water. By having a lid or the like, the denitration catalyst can be taken in and out, and the inside thereof can be sealed. It is configured in. The finish cleaning unit 104 sucks air into a vacuum state while keeping the inside closed, so as to suck and remove the particles clogged inside the denitration catalyst, particularly the coarse particles clogged in the exhaust gas passage hole. It is configured in.

The drying unit 106 is configured to remove water from the denitration catalyst washed with the chemical solution 102 or the denitration catalyst finish-cleaned with the finish cleaning unit 104. The drying unit 106 is configured to remove water adhering to the denitration catalyst by aerating a gas heated to 100 ° C. or higher, for example, a gas at 130 ° C. to the denitration catalyst. The drying unit 106 may be configured to be able to remove moisture from the denitration catalyst, and may be configured to blow off moisture from the denitration catalyst by sending dried air to the denitration catalyst, in a space heated to 100 ° C. or higher. It may be configured to evaporate water from the denitration catalyst.

Further, the finish cleaning unit 104 of the regeneration system 100 according to the present embodiment may further optionally include a jet water washing tank (not shown) for performing jet water washing. The jet water washing tank is provided with at least a water tank for washing the denitration catalyst and a water supply device, and is configured to supply washing water to the gas vents of the denitration catalyst by spraying high-pressure water assisted by compressed air. Has been done.

1.2. Regeneration Method FIG. 2 is a flowchart showing an example of the regeneration method of the denitration catalyst according to the first embodiment. As shown in FIGS. 1 and 2, the denitration catalyst regeneration method according to the present embodiment can be realized by executing the treatment in each part of the denitration catalyst regeneration system 100. The method for regenerating the denitration catalyst according to the present embodiment includes at least a chemical solution cleaning step and a finishing cleaning step. Further, as described above, it is possible to perform a dust removal step in which the catalyst does not absorb water, such as an air blow, before the chemical solution cleaning step after taking out from the denitration facility and the device. It is also possible to carry out the chemical washing step by drying after washing with water.

As shown in FIGS. 1 and 2, in the chemical solution cleaning step (step S12), a chemical solution containing a fluorine compound, an inorganic acid and a surfactant is used, and denitration in a dry state is performed in the chemical solution cleaning unit 102 filled with the chemical solution. By charging the catalyst, the denitration catalyst is immersed. The immersion time can be, for example, 15 minutes or more and 60 minutes or less. After washing the chemical solution, remove the denitration catalyst from the chemical solution. The chemical solution remaining in the chemical washing tank after the chemical solution washing can be suitably used for cleaning another dry denitration catalyst.

Examples of the fluorine compound in the chemical solution include ammonium hydrogen fluoride (NH ₄ HF ₂ ) and ammonium fluoride (NH ₄ F). The fluorine compound is preferably ammonium hydrogen fluoride. The amount of the fluorine compound can be, for example, 1 to 10% by mass with respect to the entire chemical solution, preferably in the range of 1 to 5% by mass.

Examples of the inorganic acid of the chemical solution include sulfamic acid (H ₃ NSO ₃ ), hydrochloric acid (HCl), sulfuric acid (H ₂ SO ₄ ), and boric acid (H ₃ BO ₃ ). The inorganic acid is preferably hydrochloric acid or hydrochloric acid and boric acid. Boric acid can also function as a rust inhibitor. The amount of boric acid can be, for example, 0.001 to 10% by mass with respect to the chemical solution. The inorganic acid is also preferably sulfamic acid. The amount of the inorganic acid is preferably added so that the pH value of the chemical solution is in the range of pH 1 to 6, and more preferably in the range of pH 1 to 3. As long as the amount of the acid is such that the pH value of the chemical solution is within the above range, other than the inorganic acid can be added.

As the surfactant of the chemical solution, a nonionic surfactant or an anionic surfactant is preferable. As the nonionic active agent, a non-phosphoric acid-based surfactant containing polyoxyethylene polyoxypropylene glycol, a polyoxyethylene derivative, or a polyalkylene glycol derivative as a main component is preferable. Polyoxyethylene The ethylene oxide (EO) content of polyoxypropylene glycol can be, for example, 39% by mass. Polyoxyethylene As non-phosphoric acid-based surfactants containing polyoxypropylene glycol as a main component, Braunon P-101M (manufactured by Aoki Oil & Fat Industry Co., Ltd.), Emargen PP-220 (manufactured by Kao Co., Ltd.), New Pole PE-61, New Pole PE-62, New Pole PE-64, New Pole PE-68, New Pole PE-71, New Pole PE-74, New Pole PE-75, New Pole PE-78, New Pole PE-108, etc. (Sanyo Evan 410, Evan 420, Evan 450, Evan 485, Evan 680, Evan 710, Evan 720, Evan 740, Evan 750, Evan 785, Evan U-103, Evan U-105, Evan U-108, etc. (Manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), Pronon (registered trademark) # 056, Pronon # 101P, Pronon # 105, Pronon # 124, Pronon # 124P, Pronon # 154, Pronon # 188P, Pronon # 201, Pronon # 202, Pronon # 204, Propafenone # 208, Propafenone # 235, Propafenone # 235P, Propafenone # 237P, Propafenone # 238, Propafenone # 407P, Unilube (registered trademark) 70DP-950B, Unilube 75DE-2620R, etc. (manufactured by Nichiyu Co., Ltd.), pre Examples thereof include Stall EM-440, Pristol EM-640, Pristol RM-183 and the like (manufactured by Miyoshi Oil & Fat Co., Ltd.). Examples of non-phosphoric acid-based surfactants containing a polyalkylene glycol derivative as a main component include Master Air 404 (manufactured by BASF), Foam Killer M-14 (manufactured by Aoki Oil & Fat Co., Ltd.), and Dispanol WI-115 (NOF). (Made by Oil Co., Ltd.), Unilube 50MB-2, Unilube 50MB-5, Unilube 50MB-11, Unilube 50MB-26, Unilube 50MB-72, Unilube 60MB-2B, Unilube 60MB-16, Unilube 60MB-26, Unilube 75DE-15 , Unilube 75DE-25, Unilube 75DE-60, Unilube 75DE-170, Unilube 75DE-2620, Unilube 75DE-3800, Unilube 80DE-40U, Unisafe AX-22, Unilube MB-7, Unilube MB-19, Unilube MB-7 , Unilube MB-7X, Unilube MB-11X, Unilube 10MS-250KB, etc. (manufactured by NOF Corporation), Trimin DF-300, Trimin 610, etc. (manufactured by Miyoshi Oil & Fat Co., Ltd.), Rique RK-95 (manufactured by Science and Chemical Industry Co., Ltd.) Can be mentioned. Further, as the anionic surfactant, a phosphoric acid ester-based surfactant containing a phosphoric acid ester such as a polyoxyalkylene alkyl ether phosphoric acid ester or a salt thereof as a main component is preferable. As the phosphoric acid ester-based surfactant, a surfactant containing a phosphoric acid ester such as a polyoxyethylene alkyl ether phosphoric acid ester as a main component is preferable, and a polyoxyethylene alkyl (C8) ether phosphoric acid ester / monoethanolamine salt is preferable. A surfactant containing an ester as a main component is more preferable. Examples of the phosphoric acid ester-based surfactant containing a phosphoric acid ester or a salt thereof as a main component include Antox EHD-PNA, Neucor 100-FCP, Antox EHD-400, etc. (manufactured by Nippon Embroidery Co., Ltd.), Plysurf A208F, and the like. Examples thereof include Plysurf A208N, Plysurf A210D, Plysurf M208F and the like (manufactured by Daiichi Kogyo Co., Ltd.). The amount of the surfactant can be, for example, 0.001 to 10% by mass with respect to the entire chemical solution.

In the finish cleaning step (step S14), as the vacuum drawing cleaning, the denitration catalyst taken out after the chemical solution cleaning is moved to the vacuum drawing tank of the finish cleaning unit 104. In the vacuum drawing tank, the denitration catalyst is immersed in water, the vacuum drawing tank is sealed, and the air in the tank is sucked to create a vacuum state. In the finish cleaning step, the inside of the vacuum drawing tank is evacuated so that the particles inside the denitration catalyst, particularly the coarse particles clogged in the gas passage holes, can be sucked and removed. After such finish cleaning, the vacuum drawing tank is opened to atmospheric pressure, and the denitration catalyst is taken out from the vacuum drawing tank.

In the finish cleaning step (step S14), it is preferable to reduce the air pressure in the vacuum drawing tank of the finish cleaning unit 104 to −600 mmHg or less. By reducing the air pressure in the water tank to −600 mmHg or less, coarse particles blocking the gas passage holes of the denitration catalyst can be effectively removed, and the entire area of the denitration catalyst can be immersed in water.

In the drying step (step S16), the denitration catalyst taken out after the chemical solution washing or the finish washing is moved to the drying unit 106. In the drying unit 106, the water adhering to the denitration catalyst is evaporated to dry the denitration catalyst.

Also, the finish wash step (step S14) can further include jet wash after the evacuation wash and before the drying step. In jet cleaning, cleaning water is supplied to the gas passage holes by spraying high-pressure water assisted by compressed air in the finish cleaning unit 104 or the jet water washing tank provided in the finish cleaning unit 104. As a result, the particles remaining inside the denitration catalyst can be washed away.

According to this embodiment, toxic substances such as silica (Si) adhering to the surface of the denitration catalyst and the gas passage holes are removed, and almost all the coarse particles clogged in the gas passage holes of the used denitration catalyst are removed. can do. As one of the reasons for this, it can be inferred that the effect of the chemical solution in the chemical solution cleaning step is prevented from being lowered by performing the chemical solution cleaning step on the denitration catalyst in a dry state. Further, it can be inferred that the strength of the denitration catalyst can be maintained as described later even if the used denitration catalyst is not prewashed with water before the chemical solution cleaning step. Since pre-washing can be omitted, the amount of water required for pre-washing, equipment for pre-washing, processing time, etc. can be reduced. As a result, equipment and processing costs can be reduced.

Further, one of the reasons why the coarse particles can be effectively removed is that the coarse particles clogged in the gas passage holes of the denitration catalyst are dissolved by the chemical solution cleaning to reduce the particle size, and the gas of the denitration catalyst is reduced by the finish cleaning. It can be inferred that the air bubbles in the passage hole are drawn out and the coarse particles having a smaller particle size in the gas passage hole and the poisonous substance accumulated in the gas passage hole are removed. On the other hand, it is difficult to remove the coarse particles in the gas passage holes even if the chemical solution cleaning is performed after the vacuum cleaning. This is because, for example, by simply performing vacuum cleaning, air bubbles in the gas passage hole of the denitration catalyst are taken out, and small particles accumulated in the gas passage hole are removed, but the gas passage hole is clogged. It can be inferred that there is no significant change in the particle size of the coarse particles. Further, it can be inferred that even if the chemical solution cleaning is performed after the vacuum drawing cleaning, the coarse particles in the gas passage hole remain because there is no treatment for forcibly pulling out the coarse particles in the gas passage hole.

Further, according to the present embodiment, even if the chemical solution used in the chemical solution cleaning step is repeatedly used for a plurality of used denitration catalysts, almost all of the coarse particles clogged in the gas passage holes of these used denitration catalysts are removed. can do. Further, since the chemical solution containing the fluorine compound, the inorganic acid and the surfactant is used in the chemical solution washing step, it is possible to suppress the decrease in the strength of the denitration catalyst due to the regeneration treatment.

2. 2. Second Embodiment 2.1. Regeneration system FIG. 3 shows a schematic configuration of a denitration catalyst regeneration system according to the second embodiment. As shown in FIG. 3, the denitration catalyst regeneration system 100a according to the present embodiment includes at least a chemical solution cleaning unit 102a, a finish cleaning unit 104a, 104c, a drying unit 106, and a denitration catalyst transfer device 112. The denitration catalyst transfer device 112 is a device that removes the denitration catalyst from the denitration equipment in which the denitration catalyst is installed and conveys the removed denitration catalyst. The denitration catalyst transfer device 112 can include a crane for transporting the denitration catalyst, a vehicle, a trolley for manually moving the denitration catalyst, and the like.

The chemical cleaning unit 102a includes at least a chemical washing tank 114, a chemical liquid supply device 116, and a waste liquid tank 119. The chemical washing tank 114 is a container that is larger than the denitration catalyst to be regenerated and can store a liquid. The chemical solution supply device 116 has a tank for storing the chemical solution described in the present specification, a valve for controlling the supply of the chemical solution, and the like, and is configured to supply the chemical solution used for cleaning the chemical solution to the chemical washing tank 114. .. The chemical washing unit 102a is configured to put the denitration catalyst into the chemical washing tank 114 in which the chemical liquid is stored, and to immerse the denitration catalyst in the chemical liquid. By immersing the denitration catalyst in the chemical solution in the chemical washing tank 114, the chemical washing unit 102a suppresses the elution of active ingredients such as vanadium from the denitration catalyst, and removes toxic substances such as sparingly soluble silica. It is configured to be able to be eluted from the denitration catalyst and to dissolve the particles clogged inside the denitration catalyst, particularly the coarse particles clogged in the exhaust gas passage holes, to reduce the particle size. The waste liquid tank 119 is a container for storing the chemical liquid discharged from the chemical washing tank 114.

The finish cleaning unit 104a includes at least a vacuum pump 120, a vacuum drawing tank 124a, a water supply device 126a, and a waste liquid tank 129a. The evacuation tank 124a is a container that is larger than the denitration catalyst to be regenerated and can store the liquid. The vacuum drawing tank 124a has a lid and the like, and is configured so that the denitration catalyst can be taken in and out and the inside thereof can be sealed by the vacuum pump 120. The water supply device 126a has a tank for storing water, a valve for controlling the supply of water, and the like, and is configured to supply the water used for evacuation to the evacuation tank 124a. The waste liquid tank 129a is a container for storing the waste liquid discharged from the evacuation tank 124a.

The finish washing unit 104c includes at least a finishing water washing tank 124c, a finishing water washing liquid supply device 126c, and a waste liquid tank 129c. The finishing water washing tank 124c is a container that is larger than the denitration catalyst to be regenerated and can store the liquid. The finishing water washing liquid supply device 126c has a tank for storing the finishing water washing liquid described in the present specification, a valve for controlling the supply of the finishing water washing liquid, and the like, and is configured to supply the finishing water washing liquid to the finishing water washing tank 124c. Has been done. The waste liquid tank 129c is a container for storing the finishing water washing liquid discharged from the finishing water washing tank 124c.

The drying unit 106 can preferably adopt the same configuration as the drying unit 106 of the first embodiment.

Further, the denitration catalyst regeneration system 100a according to the present embodiment may further include a jet water washing tank (not shown) for performing jet water washing between the finish cleaning unit 104a and the finish cleaning unit 104c. The jet water washing tank is equipped with a water tank for receiving washing water and a water supply device so that particles remaining inside the denitration catalyst can be washed away by spraying high-pressure water assisted by compressed air. It is configured.

2.2. Regeneration Method FIG. 4 is a flowchart showing an example of the regeneration method of the denitration catalyst according to the second embodiment. The denitration catalyst regeneration method shown in FIG. 4 can be realized by executing the treatment in each part of the denitration catalyst regeneration system 100a. The method for regenerating the denitration catalyst according to the present embodiment includes at least a chemical solution cleaning step and a finishing cleaning step.

As shown in FIG. 4, in the chemical washing step, first, the denitration catalyst is taken out from the denitration equipment by the denitration catalyst transfer device 112, and the taken out denitration catalyst is moved to the chemical washing tank 114 (step S22). After the denitration catalyst is moved to the chemical washing tank 114, the denitration catalyst is immersed in the chemical liquid supplied from the chemical liquid supply device 116 in the chemical washing tank 114 (step S24). After the chemical washing step, the chemical liquid remaining in the chemical washing tank 114 may be discharged to the discharge tank 119, maintained in the state of being stored in the chemical washing tank 114, and repeatedly used to wash another denitration catalyst. be able to. In the chemical washing step, the denitration catalyst arranged in the chemical washing tank 114 may be immersed in the chemical liquid by moving the denitration catalyst to the chemical washing tank 114 and then supplying the chemical liquid into the chemical washing tank 114. By moving the denitration catalyst to the chemical washing tank 114 in which the chemical liquid is stored, the denitration catalyst arranged in the chemical washing tank 114 may be immersed in the chemical liquid.

In the subsequent finish cleaning step, after the denitration catalyst is washed in the chemical washing tank 114, the denitration catalyst is moved to the vacuum drawing tank 124a by the denitration catalyst transfer device 112 in order to perform the vacuuming cleaning (step S30). By moving the denitration catalyst to the evacuation tank 124a, the denitration catalyst is immersed in water in the evacuation tank 124a. After the vacuum drawing tank 124a is sealed, the inside of the vacuum drawing tank 124a is evacuated by sucking the air in the vacuum drawing tank 124a with the vacuum pump 120 (step S32). By creating a vacuum inside the vacuum drawing tank 124a, foreign matter clogged inside the denitration catalyst, particularly coarse particles clogged in the gas vents, can be sucked and removed. When the inside of the vacuum drawing tank 124a is in a vacuum state, the vacuum drawing tank 124a is opened to atmospheric pressure.

Next, in the finish washing step, the denitration catalyst is moved from the vacuum drawing tank 124a to the finish water washing tank 124c by the denitration catalyst transfer device 112 in order to perform the finish water washing step (step S34). After moving the denitration catalyst to the finishing water washing tank 124c, the finishing water washing liquid is supplied from the finishing water washing liquid supply device 126c into the finishing water washing tank 124c, and the denitration catalyst is immersed in the finishing water washing liquid in the finishing water washing tank 124c. The denitration catalyst is washed (step S36). At this time, the treatment may be performed while discharging the finishing water washing liquid in the finishing water washing tank 124c, or the finishing water washing liquid may be stored in advance in the finishing water washing tank 124c before the treatment.

Examples of the finishing water washing liquid include water (H ₂ O), sulfamic acid (H ₃ NSO ₃ ), and a mixed liquid thereof. The finishing water washing solution preferably contains sulfamic acid. That is, the finishing water washing liquid is preferably a mixed liquid of water and sulfamic acid having a predetermined concentration (hereinafter, also referred to as sulfamic acid-containing water). The amount of sulfamic acid can be, for example, 0.5 mL / l to 5 mL / l with respect to water.

Then, as a drying step, the catalyst is moved to the drying section 106, and the denitration catalyst is dried in the drying section 106 (step S38).

Further, the finish cleaning step according to the present embodiment may further include a jet cleaning step after the vacuuming cleaning and before the finishing water washing step. In the jet cleaning step, cleaning water is supplied to the gas passage holes by spraying high-pressure water assisted by compressed air in a vacuum drawing tank 124a or a jet water washing tank (not shown). As a result, the particles remaining inside the denitration catalyst can be washed away. Further, the method for regenerating the denitration catalyst according to the present embodiment further includes the same drying treatment as the drying step by moving the denitration catalyst to the drying unit 106 after vacuuming washing and before the finishing water washing step. Can be done.

According to the present embodiment, as in the first embodiment, almost all of the coarse particles clogged in the gas passage holes of the used denitration catalyst are removed, and silica adhered to and deposited on the surface of the denitration catalyst and the gas passage holes. It is possible to remove toxic substances such as. Further, the denitration performance of the used denitration catalyst can be restored to almost the same level as that of the unused denitration catalyst by the finish cleaning step while exhibiting the same effect as that of the first embodiment.

Further, according to the present embodiment, the amount of water used can be reduced by omitting the pre-washing as in the first embodiment. Further, by repeatedly using the water used for vacuum cleaning, the water can be used efficiently. Efficient use of water can reduce the amount of waste liquid. Specifically, even after the denitration catalyst is taken out from the evacuation tank 124a, the state in which water is stored in the evacuation tank 124a may be maintained, the next denitration catalyst may be moved, and the evacuation cleaning may be performed. In addition, a tank for temporarily storing water and a circulation mechanism for circulating water are also provided in the vacuum drawing tank 124a, and water is once discharged from the vacuum drawing tank 124a to the tank, and when used, the tank is evacuated by the circulation mechanism. Water may be refilled in the tank 124a. As a result, the water once used for the evacuation cleaning can be repeatedly used for the evacuation cleaning for the next denitration catalyst. Further, in this case, a filter or the like may be provided in the circulation mechanism to remove foreign substances contained in the water. Further, when the finishing water washing liquid used in the finishing water washing step is water, water can be efficiently used and the amount of waste liquid can be reduced by adopting the same configuration and method as the vacuum washing. can. In addition, when the finishing water washing liquid used in the finishing water washing step is made of sulfamic acid-containing water with an emphasis on the recovery of the denitration performance of the chemical liquid, a tank or sulfamine that temporarily stores the sulfamic acid-containing water only in the finishing water washing tank 124c. A circulation mechanism is provided to circulate the acid-containing water, and the sulfamic acid-containing water is once discharged from the finishing water washing tank 124c to the tank. May be good. Further, in this case as well, a filter or the like may be provided in the circulation mechanism to remove foreign substances contained in the sulfamic acid-containing water, and a concentration meter and / or a pH meter may be provided in the circulation mechanism to wash the finishing water. Sulfamic acid-containing water may be added depending on the concentration and / or pH value of sulfamic acid in the mixture.

Further, according to the present embodiment, even after the denitration catalyst is taken out from the chemical solution, the state in which the chemical solution is stored in the waste liquid tank 119 without being discharged from the chemical washing tank 114 is maintained, and the next denitration catalyst is charged. The chemical solution can be used repeatedly. The chemical solution described in the present specification can be used efficiently without deteriorating the regeneration effect even if it is used repeatedly. Therefore, the amount of waste liquid can be reduced by efficiently using the chemical solution. Further, the present invention is not limited to the structure and method of repeatedly using the chemical solution. The chemical solution cleaning unit 102a is provided with a tank for temporarily storing the chemical solution and a circulation mechanism for circulating the chemical solution. The chemical solution may be added again. Further, in this case, a filter or the like may be provided in the circulation mechanism to remove foreign substances in the chemical solution. As a result, the chemical solution used once can be repeatedly used for cleaning another denitration catalyst. A densitometer and / or a pH meter may be provided in the circulation mechanism, and a chemical solution may be added according to the concentration and / or pH value of sulfamic acid in the finishing water washing solution. Further, the structure of the chemical solution cleaning unit 102a exemplified in the second embodiment can be suitably adopted for the chemical solution cleaning unit 102 exemplified in the first embodiment.

Further, in the present embodiment, as a finish cleaning step, a configuration and a method including at least independent tanks for performing vacuum cleaning and finishing water washing are exemplified. The present invention is not limited to this. It is also possible to provide one tank capable of performing the above-mentioned cleaning and perform the finishing cleaning step. Further, when the finish cleaning step includes the jet cleaning step, the jet cleaning step can also be performed in the one tank.

Further, in the present embodiment, a structure and a method of removing the denitration catalyst from the denitration equipment and performing the regeneration treatment are exemplified. The present invention is not limited to this. It is also possible to use a structure and a method for regenerating the denitration catalyst while the denitration catalyst is installed in the denitration facility. In this case, the chemical solution and water are supplied to the denitration equipment, and the waste liquid is collected from the denitration equipment.

Further, in the above-described embodiment, the chemical solution temperature adjusting mechanism for adjusting the temperature of the chemical solution in the chemical washing tank 114 may be provided in the denitration catalyst regeneration systems 100 and 100a. By providing the chemical liquid temperature adjusting mechanism, it is possible to control the temperature of the chemical liquid washing impregnated in the denitration catalyst. As a result, the temperature of the chemical solution washing impregnated with the denitration catalyst can be maintained at room temperature by the chemical solution temperature adjusting mechanism, or the chemical solution can be heated to be higher than normal temperature.

Further, in the above-described embodiment, a system including a chemical solution cleaning unit 102 or a chemical washing tank 102a and a finish cleaning unit 104 or a vacuuming tank 104a, and a chemical solution cleaning step and a finishing cleaning step are targeted for a denitration catalyst in a dry state. I illustrated how to prepare for it. The present invention is not limited to this. As described above, one of the reasons why the coarse particles can be effectively removed is that after the particle size of the coarse particles clogged in the gas passage hole of the denitration catalyst is reduced by chemical cleaning, vacuum cleaning is performed as a finish cleaning step. It can be inferred that the coarse particles and the toxic substance are effectively removed by the implementation. Therefore, in another embodiment, the present invention can adopt a denitration catalyst regeneration system and a regeneration method capable of performing chemical solution cleaning for a denitration catalyst before vacuuming cleaning. For example, in another embodiment of the present invention, a chemical solution cleaning unit configured to immerse the denitration catalyst in a chemical solution containing a fluorine compound, an inorganic acid, and a surfactant to wash the chemical solution, and the chemical solution taken out from the chemical solution. It is possible to adopt a denitration catalyst regeneration system including a vacuum drawing tank configured to immerse the denitration catalyst in water in a vacuum drawing tank, seal the tank, and suck air in the tank. Further, a chemical solution cleaning step of immersing the denitration catalyst in a chemical solution containing a fluorine compound, an inorganic acid and a surfactant to wash the chemical solution, and a denitration catalyst taken out from the chemical solution are immersed in water in a vacuum drawing tank, and the tank is used. A regeneration method including a finishing cleaning step of sealing and sucking the air in the tank can be adopted.

Further, in the regeneration system and the regeneration method according to another embodiment of the present invention, the denitration catalyst is evacuated by adopting the chemical solution described in the present specification in the finish cleaning step such as the vacuum suction tank and the vacuum suction cleaning. A regeneration system equipped with a vacuum drawing tank configured to immerse the tank in a chemical solution in the tank, seal the tank, and suck air in the tank, and a denitration catalyst are immersed in the chemical solution in the vacuum drawing tank. A regeneration method including a finish cleaning step of sealing the tank and sucking air in the tank can be adopted. Thereby, the chemical solution cleaning unit and the chemical solution cleaning step can be omitted, and a more efficient catalyst regeneration system and regeneration method can be provided.

Hereinafter, the present invention will be described in more detail by way of examples. The denitration catalyst regeneration method and the denitration catalyst regeneration system according to the present invention are not limited to the following examples.

1. 1. Verification of reproduction effect I
As Example 1, the method for regenerating the denitration catalyst according to the above-described embodiment was carried out for the used denitration catalyst taken out from the actual machine, and the change in the clogging rate of the denitration catalyst was verified as one of the regeneration effects.

As a chemical solution used for cleaning the chemical solution, ammonium hydrogen fluoride (NH ₄ HF ₂ ) as a fluorine compound has a hydrogen fluoride content of 1.75% by mass, and sulfamic acid (H ₃ NSO ₃ ) has an inorganic acid content of 3.2% by mass. A chemical solution was prepared by mixing a commercially available nonionic surfactant containing polyoxyethylene polyoxypropylene glycol as a main component in a proportion of 0.05% by mass.

1.1. Measurement of clogging rate I
The used denitration catalyst was taken out from the actual machine, and the clogging rate of the taken out denitration catalyst was measured by visually counting the number of clogged gas vents (cells). For the calculation of the clogging rate, the formula of clogging rate (%) = number of clogged cells / total number of cells × 100 was used. As the denitration catalyst, a honeycomb-shaped denitration catalyst (honeycomb denitration catalyst) having a gas vent hole (honeycomb hole) of 5 mm square and having a size of 150 mm × 150 mm × 600 mm was used. Then, the denitration catalyst in a dry state was immersed in the chemical solution at room temperature for 60 minutes in the chemical washing tank. After washing with the chemical solution, the denitration catalyst was immersed in water in a vacuum drawing tank, and the vacuum drawing cleaning was performed by sucking the air in the tank at room temperature for 60 minutes while sealing the tank. This evacuation washing was repeated once again under the same conditions, and was carried out twice in total. After vacuuming and washing, the denitration catalyst taken out from the tank was dried at 110 ° C. for 4 hours or more. The clogging rate of the denitration catalyst after drying was measured in the same manner as described above.

Next, the second used denitration catalyst was taken out from the actual machine, and the chemical solution used for cleaning the chemical solution of the first denitration catalyst was repeatedly used for the dry denitration catalyst to achieve the same regeneration treatment and clogging rate. The measurement was carried out. As described above, the second used denitration catalyst taken out from the actual machine was repeatedly regenerated twice using the same chemical solution, and the change in the clogging rate was verified. As Comparative Example 1, a third used denitration catalyst was taken out from the actual machine, and the dry denitration catalyst was regenerated by pre-washing with water instead of the above-mentioned chemical solution. The clogging rate was measured. Further, for each denitration catalyst, the clogging removal rate was calculated from the difference in the clogging rate before and after the regeneration treatment. For the calculation of the clogging removal rate, the formula of clogging removal rate (%) = (1-number of cells remaining clogged after washing / number of clogging cells before washing) × 100 was used. The contents of one reproduction process of Example 1 and Comparative Example 1 are shown in Table 1 below. The results of the clogging rate and the clogging removal rate are shown in FIGS. 5 and 6.

1.2. Performance I
As shown in FIG. 5, the clogging rate was reduced from 17.1% to 0.5% by the first regeneration treatment performed on the first used denitration catalyst. The second regeneration treatment performed on the second used denitration catalyst reduced the clogging rate from 16.3% to 1.4%. On the other hand, the clogging rate of Comparative Example 1 in which water was used instead of the chemical solution was only reduced from 19.7% to 2.4% in spite of the first regeneration treatment. Further, as shown in FIG. 6, the clogging was removed by 97.2% in the first regeneration process and 91.2% in the second regeneration process. On the other hand, in Comparative Example 1 in which water was used instead of the chemical solution, the clogging removal rate was 87.8% despite the first regeneration treatment.

From the results, the used denitration catalyst in a dry state taken out from the actual machine was washed with a chemical solution containing a fluorine compound, an inorganic acid and a surfactant, and then vacuumed to remove the denitration catalyst. It was found that almost all of the coarse particles stuck inside could be removed. In addition, even if the same chemical solution is used repeatedly, if the used denitration catalyst in a dry state taken out from the actual machine is washed with the chemical solution and vacuumed, the coarse particles clogged in the second used denitration catalyst can be found. It turns out that almost everything can be removed.

1.3. Measurement of clogging rate II
As Example 2, the used denitration catalyst taken out from the actual machine was immersed in the chemical solution at room temperature for 30 minutes in the same manner as in Example 1. As the chemical solution, a fluorine-based chemical solution different from that of Example 1 was used. After washing with the chemical solution, the denitration catalyst was immersed in water in a vacuum drawing tank, and the vacuum drawing cleaning was performed by sucking the air in the tank at room temperature for 60 minutes while sealing the tank. This evacuation washing was repeated once again under the same conditions, and was carried out twice in total. After vacuuming and washing, the denitration catalyst taken out from the tank was dried at 110 ° C. for 4 hours or more. The clogging rate of the denitration catalyst after drying was measured in the same manner as described above. Further, as Comparative Example 2, the second used denitration catalyst from the actual machine is immersed in water in a vacuum drawing tank, and the air in the tank is sucked at room temperature for 60 minutes while the tank is sealed to create a vacuum. Cleaning was performed. This evacuation washing was repeated once again under the same conditions, and was carried out twice in total. Next, the denitration catalyst was immersed in the same chemical solution as in Example 2 for 60 minutes at room temperature in the chemical washing tank. After washing with the chemical solution, the denitration catalyst taken out from the tank was dried at 110 ° C. for 4 hours or more. The clogging rate of the denitration catalyst after drying was measured in the same manner as described above. The contents of one reproduction process of Example 2 and Comparative Example 2 are shown in Table 2 below.

1.4. Performance II
The clogging rate of Example 2 was 4.7%, and the clogging rate of Comparative Example 2 was 7.8%. From the results, it was found that the coarse particles clogged in the denitration catalyst can be efficiently removed by performing vacuum cleaning after cleaning with the chemical solution. It can be inferred that this is because the chemical solution reacts with the coarse particles clogged in the denitration catalyst to reduce the size of the coarse particles, thereby making the subsequent evacuation effective.

2. 2. Verification of regeneration effect II
Next, as Example 3, the method for regenerating the denitration catalyst according to the above-described embodiment was carried out for the used denitration catalyst taken out from the actual machine, and the degree of recovery of the denitration performance of the denitration catalyst was verified as one of the regeneration effects. .. The reaction rate constant of the denitration catalyst was used as an index of the denitration performance of the denitration catalyst.

2.1. Measurement of denitration reaction rate constant ratio of denitration catalyst
The reaction rate constant K ₀ of the denitration catalyst unused in the actual machine (denitration catalyst when new) was obtained. Next, the same chemical solution as in Example 1 was used for the first used denitration catalyst in a dry state taken out from the actual machine, and the chemical solution washes, vacuumed and dried in the same manner as in Example 1. .. Then, the second used denitration catalyst in a dry state was taken out from the actual machine, and the reaction rate constant K was obtained. The same chemical solution was repeatedly used for the second used denitration catalyst, and the chemical solution washes, vacuumed and dried in the same manner. Then, the denitration catalyst after drying was finished with water for 30 minutes at room temperature using a finishing water washing solution prepared so that the concentration of sulfamic acid was 1N, and dried at 110 ° C. overnight. The reaction rate constant K was determined for the denitration catalyst performance of the denitration catalyst after drying. From the obtained K and K ₀ values, the denitration reaction rate constant ratio (measured reaction rate constant of the denitration catalyst / reaction rate constant of the denitration catalyst when new: K / K ₀ ) was obtained. The reaction rate constants of each sample were measured with the gas having the properties shown in Table 3 below using a tube-type flow reaction tester. The results are shown in FIG.

2.2. Performance III
As shown in FIG. 7, when the denitration reaction rate constant ratio of the unused denitration catalyst is 1.0, the denitration reaction rate constant ratio of the used denitration catalyst is 0.5 immediately after being taken out from the actual machine and before cleaning. After cleaning, it improved to the same level as the unused denitration catalyst. Therefore, it was found that the denitration performance of the used catalyst taken out from the actual machine was restored to the same level as that of the unused catalyst by the regeneration method according to the above-described embodiment.

From the results, the denitration performance of the used denitration catalyst in the dry state taken out from the actual machine is restored to the same level as the unused denitration catalyst by performing finish washing with sulfamic acid-containing water after vacuum washing and chemical washing. I found that I could do it. It was also found that the second used denitration catalyst can be recovered to the same extent as the unused denitration catalyst.

3. 3. Verification of Denitration Catalyst Strength Next, as Example 4, by verifying the effect of prewashing on the strength of the denitration catalyst, the effect on the strength of the denitration catalyst by the regeneration method according to the above-described embodiment was estimated.

3.1. Measurement of silica elution amount The used denitration catalyst taken out from the actual machine was put into a chemical washing tank in which the chemical solution was stored in a dry state, and immersed in the chemical solution. The amount of silica eluted by the immersion time was measured by measuring the concentration of silica in the chemical solution while immersing the denitration catalyst. The results are shown in FIG.

3.2. Performance IV
As shown in FIG. 7, the amount of silica eluted from the used denitration catalyst was saturated at a constant value. Generally, it is known that a used denitration catalyst is treated with water to fill the inside of the denitration catalyst by immersing it in water as a pre-wash before vacuuming. It is known that this can prevent the chemical solution from entering the inside of the denitration catalyst and prevent the dissolution of silica in the glass fiber contained in the denitration catalyst, so that the strength of the denitration catalyst can be prevented (for example). Japanese Patent Application Laid-Open No. 2011-31237). On the other hand, from the results of this example, it was found that the concentration of silica eluted from the denitration catalyst was rapidly saturated by the chemical solution cleaning treatment with the chemical solution. Since the diffusion of the chemical solution filled in the pores in the denitration catalyst is very slow, the dissolution of silica in the glass fiber quickly reaches the saturated solubility. That is, from the results of this example, it can be inferred that the strength of the denitration catalyst is maintained even if the chemical solution cleaning treatment is directly applied to the dry denitration catalyst taken out from the actual machine without performing the prewash. ..

According to the denitration catalyst regeneration method and the denitration catalyst regeneration system according to the present invention, the toxic substance adhering to the denitration catalyst can be removed. Further, it is possible to remove the coarse particles clogged in the gas passage hole of the denitration catalyst. It is also possible to remove the coarse particles clogged inside the denitration catalyst.

100, 100a: Denitration catalyst regeneration system 102, 102a: Chemical cleaning unit 104, 104a: Finish cleaning unit 106: Drying unit 112: Denitration catalyst transfer device 114: Chemical washing tank 116: Chemical liquid supply device 119, 129a, 129c: Waste liquid Tank 120: Vacuum pump 124a: Vacuum drawing tank 126a: Water supply device 124c: Finishing water washing tank 126c: Finishing water washing liquid supply

Claims (13)

A method for regenerating a denitration catalyst, which comprises a chemical solution cleaning step of immersing the denitration catalyst in a chemical solution containing a fluorine compound, an inorganic acid and a surfactant in a dry state and cleaning the chemical solution. The first aspect of the present invention is characterized by further comprising a finish cleaning step of immersing the denitration catalyst taken out from the chemical solution in water in a vacuum drawing tank, sealing the tank, and sucking air in the tank. How to regenerate the denitration catalyst. The fluorine compound is ammonium hydrogenfluoride, the amount of the fluorine compound is 1 to 10% by mass with respect to the whole chemical solution, and the amount of the inorganic acid is such that the pH value of the chemical solution is pH 1 to 6. The denitration catalyst according to claim 1 or 2, wherein the amount is added so as to be within the range, and the amount of the surfactant is 0.001 to 10% by mass with respect to the entire chemical solution. How to play. 2. The finish washing step further includes a finishing water washing step in which the denitration catalyst taken out from the tank is washed with water or sulfamic acid-containing water as a washing liquid after washing in the evacuation tank. The method for cleaning the denitration catalyst according to. The method according to any one of claims 1 to 4, wherein in the chemical solution cleaning step, cleaning is performed by directly immersing the denitration catalyst removed from the denitration facility in the chemical solution in the chemical washing tank. How to regenerate the denitration catalyst. The surfactant is a nonionic surfactant containing polyoxyethylene polyoxypropylene glycol, a polyoxyethylene derivative or a polyalkylene glycol derivative as a main component, or an anionic surfactant containing a polyoxyalkylene alkyl ether phosphoric acid ester as a main component. The method for regenerating a denitration catalyst according to any one of claims 1 to 5, which is a surfactant. The fluorine compound is ammonium hydrogenfluoride, the inorganic acid is sulfamic acid, and the surfactant is a nonionic surfactant containing polyoxyethylene polyoxypropylene glycol as a main component. The method for regenerating a denitration catalyst according to any one of claims 1 to 6. The method for regenerating a denitration catalyst according to any one of claims 1 to 7, wherein in the chemical solution washing step, the chemical solution is repeatedly used. A denitration catalyst regeneration system, comprising at least a chemical cleaning unit configured to immerse the denitration catalyst in a chemical solution containing a fluorine compound, an inorganic acid, and a surfactant in a dry state to clean the chemical solution. The claim is characterized in that the denitration catalyst taken out from the chemical solution is immersed in water in a vacuum drawing tank, and the vacuum drawing tank is further provided so as to seal the tank and suck air in the tank. 9. The denitration catalyst regeneration system according to 9. The fluorine compound is ammonium hydrogen fluoride, the amount thereof is 1 to 10% by mass with respect to the whole chemical solution, and the amount of the inorganic acid is added so that the pH value of the chemical solution is in the range of pH 1 to 6. The regeneration system for a denitration catalyst according to claim 9 or 10, wherein the amount of the surfactant is 0.001 to 10% by mass based on the total amount of the chemical solution. The regeneration system for a denitration catalyst according to claim 10, further comprising a finishing water washing tank for finishing and washing the denitration catalyst taken out from the evacuation tank with water or sulfamic acid-containing water as a finishing water washing liquid. Any of claims 9 to 12, wherein the chemical solution cleaning unit is configured to perform cleaning by directly immersing the denitration catalyst removed from the denitration facility in the chemical solution in the chemical washing tank. The regeneration system for the denitration catalyst according to item 1.

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