Method for determining catalyst arrangement in denitration device, method for maintaining denitration device, and denitration device, boiler, and power plant

Abstract

To provide a catalyst arrangement determination method of a nitration apparatus that makes it possible to use a catalyst apparatus continuously for a long time and a maintenance method of the nitration apparatus.SOLUTION: A catalyst arrangement determination method of a denitration apparatus is a catalyst arrangement determination method of a denitration apparatus including a catalyst layer provided in an exhaust gas flow path, comprises a step of investigating the location dependence of a deterioration state of the catalyst in the catalyst layer after an operation period has elapsed. and a step of determining a first region of the catalyst layer using a first catalyst and a second region of the catalyst layer using a second catalyst different from the first catalyst based on the location dependence.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present disclosure relates to a catalyst arrangement determination method for a denitration device, a maintenance method for a denitration device, and a denitration device, a boiler, and a power generation plant. [Background technology]

[0002] Nitrogen oxides (NOx) contained in exhaust gases from combustion equipment such as power generation boilers, gas turbines, and combustion furnaces can be removed or reduced by breaking them down into harmless nitrogen and water using a reducing agent in the presence of a denitration catalyst.

[0003] For example, Patent Document 1 discloses a denitration device for removing nitrogen oxides in exhaust gas from a pulverized coal-fired boiler. This denitration device includes multiple denitration catalyst layers provided in an exhaust gas passage through which exhaust gas from the pulverized coal-fired boiler flows. Of the multiple denitration catalyst layers, the denitration catalyst layer provided on the upstream side of the exhaust gas flow is made of a plate-shaped catalyst (plate-shaped catalyst), and the denitration catalyst layer provided on the downstream side of the exhaust gas flow is made of a honeycomb-shaped catalyst (honeycomb catalyst). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6768092 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, each of the denitration catalyst layers provided in the exhaust gas passage is usually composed of a single type of catalyst (e.g., a plate catalyst or a honeycomb catalyst). In addition, when the performance or function of the denitration device deteriorates after a period of operation of the combustion equipment, the equipment including the denitration device is stopped and the catalyst constituting the catalyst layer is replaced with an unused catalyst of the same type in order to maintain the performance and function of the denitration device. There are two ways to replace the catalyst: either all of the catalyst constituting the catalyst layer is replaced or only a portion of the catalyst whose performance or function has deteriorated relatively significantly is replaced. However, when attempting to maintain the performance and function of the denitration device by replacing with the same type of catalyst, the performance and function of only a portion of the catalyst constituting the catalyst layer tends to deteriorate, and the replacement frequency tends to be relatively high, making it difficult to use the denitration device continuously for a long period of time.

[0006] In view of the above circumstances, an object of at least one embodiment of the present invention is to provide a method for determining a catalyst arrangement for a denitration device and a maintenance method for the denitration device that enable long-term continuous use of the denitration device. [Means for solving the problem]

[0007] A method for determining catalyst arrangement in a denitration device according to at least one embodiment of the present invention includes the steps of: A method for determining catalyst arrangement in a denitration device including a catalyst layer provided in an exhaust gas flow passage, comprising: investigating the location dependency of a deterioration state of the catalyst in the catalyst layer after an operating period has elapsed; determining a first region of the catalyst layer that uses a first catalyst and a second region of the catalyst layer that uses a second catalyst different from the first catalyst based on the location dependence; Equipped with.

[0008] Further, a maintenance method for a denitration device according to at least one embodiment of the present invention includes the steps of: A step of replacing at least a part of the catalyst constituting the catalyst layer with the first catalyst or the second catalyst so that the first catalyst is disposed in the first region and the second catalyst is disposed in the second region determined by the above-mentioned catalyst arrangement determination method. Equipped with.

[0009] In addition, a method for determining catalyst arrangement in a denitration device according to at least one embodiment of the present invention includes the steps of: A method for determining a catalyst arrangement for a denitration device provided in an exhaust gas flow passage, comprising: A step of investigating location dependency of a deterioration state of a catalyst in a catalyst layer of the investigation denitration device after an operating period of a plant in which an investigation denitration device other than the denitration device is installed has elapsed; determining a first region of a catalyst layer of the denitration device that uses a first catalyst and a second region of a catalyst layer of the denitration device that uses a second catalyst different from the first catalyst based on the location dependency; Equipped with. Effect of the Invention

[0010] According to at least one embodiment of the present invention, there are provided a method for determining the catalyst arrangement in a denitration device and a method for maintaining the denitration device, which enable long-term continuous use of the denitration device. [Brief description of the drawings]

[0011] [Figure 1] 1 is a schematic diagram of a combustion facility including a denitration device to which a catalyst arrangement determination method according to an embodiment is applied. [Diagram 2] FIG. 2 is a view taken along the line AA in FIG. [Diagram 3] FIG. 2 is a partial cross-sectional view of a catalyst constituting a catalyst layer according to one embodiment. [Figure 4] FIG. 2 is a partial cross-sectional view of a catalyst constituting a catalyst layer according to one embodiment. [Diagram 5] 2 is a flowchart of a catalyst arrangement determination method and a maintenance method for a denitration apparatus according to an embodiment. [Figure 6] FIG. 2 is a diagram for explaining a catalyst arrangement method according to an embodiment. [Figure 7] 4 is a flowchart of a catalyst arrangement determination method for a denitration device according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of components described as the embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the present invention.

[0013] (Combustion equipment and denitrification equipment configuration) Fig. 1 is a schematic diagram of a combustion facility including a denitration device to which a catalyst arrangement determination method according to some embodiments is applied. Fig. 2 is a view taken along the line AA in Fig. 1.

[0014] As shown in FIG. 1, the combustion equipment 1 includes a flue (duct) 2 to which exhaust gas is guided from a combustion furnace (not shown) for burning fuel such as coal, and a denitrification device 20 for removing or reducing nitrogen oxides (NOx) from the exhaust gas flowing through the flue 2. A heat transfer tube (not shown) may be provided inside the flue 2 at a position upstream of the denitrification device 20, and the fluid (water, steam, etc.) supplied to the heat transfer tube may be heated by heat exchange between the exhaust gas and the fluid. The denitrification device 20 may be configured to receive the exhaust gas after passing through the above-mentioned heat transfer tube. The fluid (steam, etc.) heated by the heat transfer tube may be configured to drive a generator. That is, the combustion equipment 1 may be a boiler constituting a power generation plant.

[0015] The exhaust gas from which nitrogen oxides have been removed or reduced by the denitration device 20 is discharged to the outside via a downstream portion 2c of the flue 2 located downstream of the denitration device 20, and a chimney 8 connected to the downstream portion 2c. The downstream portion 2c of the flue 2 may be provided with a heater 10 for raising the temperature of a fluid (e.g., air) using the exhaust gas flowing through the downstream portion 2c as a heat source. The downstream portion 2c of the flue 2 may also be provided with a device for removing or reducing soot such as combustion ash and sulfur oxides (SOx) contained in the exhaust gas.

[0016] The denitration device 20 includes a reducing agent supply unit 22 for supplying a reducing agent into the flue 2, and at least one catalyst layer 24 provided downstream of the reducing agent supply unit 22 in the flue 2. In the exemplary embodiment shown in FIG. 1, the denitration device 20 includes three catalyst layers 24.

[0017] The reducing agent supply unit 22 is configured to supply a reducing agent having an effect of reducing nitrogen oxides in the exhaust gas to the exhaust gas flow passage 4 formed by the first portion 2a of the flue 2. The reducing agent may contain ammonia, ammonia water, or urea water. The reducing agent supply unit 22 may be configured to supply the reducing agent in the form of droplets or gas into the flue 2.

[0018] The catalyst layer 24 includes a catalyst 26 (see FIG. 2) for promoting a reaction between nitrogen oxides in the exhaust gas and a reducing agent. The catalyst layer 24 is provided in an exhaust gas flow passage 4 formed by a second portion 2b of the flue 2, which is located downstream of the exhaust gas flow from the above-mentioned first portion 2a. Each catalyst layer 24 is provided so as to extend along a plane perpendicular to the exhaust gas flow direction (or a plane perpendicular to the extension direction of the second portion 2b of the flue 2). When multiple catalyst layers 24 are provided in the exhaust gas flow passage 4, the multiple catalyst layers 24 are arranged in the exhaust gas flow passage 4 along the exhaust gas flow direction. Each catalyst layer 24 is supported on the second portion 2b of the flue 2 by a support member (not shown).

[0019] 2, the catalyst layer 24 includes a plurality of catalysts (catalyst modules) 26 arranged along a plane perpendicular to the exhaust gas flow direction (or a plane perpendicular to the extending direction of the second portion 2b). Each of the plurality of catalysts 26 includes a carrier and a catalytic component supported on the carrier. The catalytic component is a substance that has the effect of promoting the reaction between nitrogen oxides and a reducing agent, and may include, for example, vanadium or tungsten.

[0020] Each of the catalyst layers 24 has an upstream end 24a and a downstream end 24b, which are both ends in the exhaust gas flow direction. The exhaust gas flowing through the exhaust gas flow passage 4 flows into the catalyst layer 24 through the upstream end 24a of each catalyst layer 24, passes through the catalyst 26, and then flows out of the catalyst layer 24 through the downstream end 24b.

[0021] Figures 3 and 4 are partial cross-sectional views of a catalyst 26 constituting a catalyst layer 24 according to one embodiment. The catalyst 26 shown in Figure 3 is a plate-shaped catalyst 26A, and the catalyst 26 shown in Figure 4 is a honeycomb catalyst 26B. These cross-sectional views show a cross section of the catalyst 26 perpendicular to the exhaust gas flow direction.

[0022] Each of the catalysts 26 has a plurality of cells 27 extending along the exhaust gas flow direction. Both ends of the cells 27 in the exhaust gas flow direction are open. Therefore, the exhaust gas flowing through the exhaust gas flow passage 4 can pass through each of the plurality of cells 27.

[0023] As shown in FIGS. 3 and 4, the plurality of cells 27 may be formed by a carrier 28 .

[0024] 3 includes a plurality of plate portions 29 arranged substantially parallel to each other, and a support portion 30 provided between a pair of adjacent plate portions 29 for supporting the plate portions 29 while maintaining the interval between the pair of plate portions 29. In the plate catalyst 26A shown in FIG. 3, cells 27 are formed as spaces partitioned by the plate portions 29 and the support portions 30.

[0025] The honeycomb catalyst 26B shown in Fig. 4 has a honeycomb structure formed by a carrier 28. In the exemplary embodiment shown in Fig. 4, the carrier 28 of the honeycomb catalyst 26B has a lattice shape in a cross section perpendicular to the exhaust gas flow direction. In the honeycomb catalyst 26B shown in Fig. 4, cells 27 are formed as spaces separated by the honeycomb structure formed by the carrier 28.

[0026] 3 and 4, L and A respectively indicate the perimeter length and the flow path cross-sectional area of ​​the cell 27 in a cross section perpendicular to the exhaust gas flow direction. The hydraulic diameter of the cell 27 can be expressed as (4×A) / L.

[0027] Plate catalysts are characterized by relatively small pressure loss and relatively excellent wear resistance, while honeycomb catalysts are characterized by relatively high denitration performance per unit volume.

[0028] As shown in FIG. 1, the denitrification device 20 further includes a first pressure measurement unit 31, a second pressure measurement unit 32, a first NOx concentration measurement unit 33, a second NOx concentration measurement unit 34, a first SOx concentration measurement unit 35, a second SOx concentration measurement unit 36, and a reducing agent concentration measurement unit 38.

[0029] The first pressure measuring unit 31 is configured to measure the pressure in the flue 2 at a position upstream of the catalyst layer 24. The second pressure measuring unit 32 is configured to measure the pressure in the flue 2 at a position downstream of the catalyst layer 24. The first NOx concentration measuring unit 33 is configured to measure the concentration of NOx (nitrogen oxides) in the flue 2 at a position upstream of the catalyst layer 24. The second NOx concentration measuring unit 34 is configured to measure the concentration of NOx in the flue 2 at a position downstream of the catalyst layer 24. The first SOx concentration measuring unit 35 is configured to measure the concentration of SO3 (sulfur trioxide) in the flue 2 at a position upstream of the catalyst layer 24 by precipitation titration. The second SOx concentration measuring unit 36 ​​is configured to measure the concentration of SO3 in the flue 2 at a position downstream of the catalyst layer 24 by precipitation titration. The reducing agent concentration measuring unit 38 is configured to measure the concentration of a reducing agent (e.g., ammonia) in the flue 2 at a position downstream of the catalyst layer 24.

[0030] The first pressure measurement unit 31 may be configured to measure the pressure at each of a plurality of first positions in the flow cross section of the flue 2 on the upstream side of the catalyst layer 24. The second pressure measurement unit 32 may be configured to measure the pressure at each of a plurality of second positions in the flow cross section of the flue 2 on the downstream side of the catalyst layer 24. That is, the first pressure measurement unit 31 and the second pressure measurement unit 32 may each be configured to measure the in-plane distribution of pressure in the flue 2. Here, each of the multiple second positions is a position corresponding to each of the multiple first positions.

[0031] The first NOx concentration measurement unit 33 may be configured to measure the concentration of NOx (nitrogen oxides; NO2, NO, etc.) at each of a plurality of third positions in the flow cross section of the flue 2 on the upstream side of the catalyst layer 24. The second NOx concentration measurement unit 34 may be configured to measure the concentration of NOx at each of a plurality of fourth positions in the flow cross section of the flue 2 on the downstream side of the catalyst layer 24. Here, each of the plurality of fourth positions is a position corresponding to each of the plurality of third positions.

[0032] The first SOx concentration measurement unit 35 may be configured to measure the concentration of SO3 at each of a plurality of fifth positions in a flow cross section of the flue 2 on the upstream side of the catalytic layer 24. The second SOx concentration measurement unit 36 ​​may be configured to measure the concentration of SO3 at each of a plurality of sixth positions in a flow cross section of the flue 2 on the downstream side of the catalytic layer 24. Here, each of the plurality of sixth positions is a position corresponding to each of the plurality of fifth positions.

[0033] The reducing agent concentration measurement unit 38 may be configured to measure the concentration of the reducing agent at each of a plurality of seventh positions in the flow path cross section of the flue 2 downstream of the catalyst layer 24. When ammonia is used as the reducing agent, the reducing agent concentration measurement unit 38 is configured to measure the ammonia concentration in the flue 2.

[0034] (Method for determining catalyst arrangement and maintenance method for denitrification equipment) Hereinafter, a catalyst arrangement determination method and a maintenance method for a denitration device according to several embodiments will be described. In the following description, the denitration device 20 included in the above-mentioned combustion equipment 1 is the maintenance target. Fig. 5 is a flowchart of a catalyst arrangement determination method and a maintenance method for a denitration device according to one embodiment. Fig. 6 is a diagram for explaining a catalyst arrangement method according to one embodiment.

[0035] As shown in FIG. 5, in some embodiments, a first region and a second region in catalyst layer 24 are determined according to a catalyst arrangement determination method of one embodiment (S2 to S4), and a portion of catalyst 26 constituting catalyst layer 24 is replaced with the first catalyst or the second catalyst so that the first catalyst is arranged in the first region thus determined, and the second catalyst is arranged in the second region (S6).

[0036] In step S2, the location dependency of the deterioration state of the catalyst 26 in the catalyst layer 24 of the denitration device 20 is investigated after the operation period of the denitration device 20 has elapsed (i.e., after the operation period of the combustion equipment 1 including the denitration device 20 has elapsed).

[0037] The degree to which catalyst deterioration progresses varies depending on the flow rate, temperature, pressure, components, particle concentration of combustion ash, etc., of the exhaust gas in the exhaust gas flow passage in which the catalyst is disposed, or the distribution of these, etc. Therefore, the deterioration state (degree of deterioration) of the catalyst 26 differs depending on the position in the catalyst layer 24. By investigating the location dependency of the deterioration state of the catalyst 26 in the catalyst layer 24 in step S2 as described above, it is possible to identify areas in the catalyst layer 24 where deterioration of the catalyst 26 is relatively advanced and areas where deterioration is relatively unadvanced.

[0038] The investigation of the location dependency of the deterioration state of the catalyst 26 in step S2 may be performed by directly inspecting the catalyst 26 in the catalyst layer 24 while the combustion equipment 1 is stopped, or may be performed based on measurement data obtained while the combustion equipment 1 is operating.

[0039] In step S4, based on the result of the investigation of the location dependency of the deterioration state of the catalyst 26 in step S2, a first region of the catalyst layer 24 using a first catalyst and a second region of the catalyst layer using a second catalyst different from the first catalyst are determined. As exemplified below, the first catalyst and the second catalyst are different in at least one of the structure (shape, size, etc.) of the catalyst, the characteristics required of the catalyst (durability, ash passing, pressure loss, wear resistance, etc.), and the catalytic performance. The first region and the second region are regions where the deterioration state of the catalyst 26 is different from each other, and one of the first region and the second region is a region where the deterioration of the catalyst 26 is more advanced than the other, or a region where the deterioration of the catalyst 26 is more likely to progress. The first region and the second region may be set so as not to overlap each other in a plane perpendicular to the exhaust gas flow direction (or the second part 2b of the flue 2), as shown in FIG. 6, for example. In FIG. 6, the region A1 is the first region, and the region A2 is the second region. By placing one of the first and second catalysts, which is less susceptible to deterioration, in one of the first and second regions in which deterioration is more likely to progress, and placing the other catalyst in the other region, it is possible to suppress the progression of catalyst deterioration in the catalyst layer 24 as a whole.

[0040] In the denitration device 20 including the catalyst layer 24 made of the catalyst 26, certain events related to the deterioration of the catalyst 26 (for example, catalyst wear or deposition of combustion ash on the catalyst, etc.) are likely to occur in certain regions of the catalyst layer 24. In addition, the likelihood of occurrence and progression of such events differs depending on the type of catalyst. In this regard, according to the method including the above-mentioned steps S2 to S4, the location dependency of the deterioration state of the catalyst 26 in the catalyst layer 24 is investigated, and the first and second regions of the catalyst layer 24 that use the different first and second catalysts, respectively, are determined based on the location dependency. Therefore, if the first and second catalysts are appropriately selected, the occurrence and progression of events related to the deterioration of the catalyst can be suppressed by arranging the first and second catalysts in the catalyst layer according to this determination. Therefore, it is possible to suppress the deterioration of the performance or function of the denitration device 20, and it is possible to continuously use the denitration device 20 for a longer period of time.

[0041] More specifically, steps S2 to S4 can be executed as follows.

[0042] In one embodiment, in step S2, the location dependency of the wear state of the catalyst 26 in the catalyst layer 24 is investigated as the deterioration state of the catalyst 26. In this investigation, for example, a region in the catalyst layer 24 where the wear of the catalyst 26 is relatively advanced and a region where the wear is relatively advanced are identified. Then, in step S4, based on the investigation of the location dependency in step S2, the region in the catalyst layer 24 where the wear is relatively advanced is determined as a first region where a first catalyst is used, and the region where the wear is relatively advanced is determined as a second region where a second catalyst is used. Here, the first catalyst is a catalyst having better wear resistance than the second catalyst.

[0043] The location dependency of the wear state of the catalyst 26 may be investigated by performing a visual inspection of each of the multiple catalysts 26 constituting the catalyst layer 24 while the combustion equipment 1 is stopped. In this case, a region including a catalyst 26 in which a through hole is detected in the carrier 28 as a result of the visual inspection may be identified as a region in which the catalyst wear has progressed relatively.

[0044] Alternatively, the location dependency of the wear state of the catalyst 26 may be investigated by measuring the dimensions of the worn parts of each of the multiple catalysts 26 constituting the catalyst layer 24 while the combustion equipment 1 is stopped. In this case, a region including the catalyst 26 where wear or loss is detected to a depth of 100 mm or more from the upstream end 24a to the downstream end 24b over, for example, ¼ or more of the catalyst surface as a result of the dimension measurement may be identified as a region where catalyst wear is relatively advanced.

[0045] In one embodiment, in step S2, the location dependency in the catalyst layer 24 of the state of ash deposition on the catalyst 26 as a deterioration state of the catalyst 26 is investigated. In this investigation, for example, a region in the catalyst layer 24 where ash deposition on the catalyst 26 has progressed relatively and a region where ash deposition has not progressed relatively are identified. Then, in step S4, based on the investigation of the location dependency in step S2, a region in the catalyst layer 24 where ash deposition on the catalyst 26 has progressed relatively is determined as a first region using a first catalyst, and a region where ash deposition on the catalyst 26 has not progressed relatively is determined as a second region using a second catalyst. Here, the first catalyst is a catalyst on which ash is less likely to accumulate than the second catalyst.

[0046] In the combustion equipment 1, ash (combustion ash) is generated together with the combustion gas by the combustion of the fuel. Some of the ash accumulates in the lower part of the combustion furnace and is discharged to the outside of the combustion furnace via the ash discharge part, while some of the ash is entrained in the combustion gas as fly ash and is led to the flue 2. In this way, the ash enters the flue 2 together with the exhaust gas, and therefore the ash may accumulate on the catalyst 26 arranged inside the flue 2.

[0047] The location dependency of the ash deposition state on the catalyst 26 may be investigated by performing a visual inspection on each of the multiple catalysts 26 constituting the catalyst layer 24 while the combustion equipment 1 is stopped. In this case, as a result of the visual inspection, a region including a catalyst 26 in which the clogged flow passage area (for example, the proportion of blocked cells 27) is a predetermined ratio, for example, 50% or more of the total, when viewed in the exhaust gas flow direction may be identified as a region in which ash deposition on the catalyst has progressed relatively.

[0048] Alternatively, the location dependency of the ash deposition state on the catalyst 26 may be investigated by measuring the pressure in the flue 2 during operation of the combustion equipment 1. In this case, the first pressure measuring unit 31 and the second pressure measuring unit 32 measure the pressure at the above-mentioned multiple first positions and multiple second positions corresponding to the multiple first positions. Then, a region including a position where the difference between the pressure measurement value by the first pressure measuring unit 31 and the pressure measurement value by the second pressure measuring unit 32 is equal to or greater than a specified value may be identified as a region where ash deposition on the catalyst has progressed relatively. Alternatively, a region including a position where the increase rate of the difference (pressure loss) between the pressure measurement value by the first pressure measuring unit 31 and the pressure measurement value by the second pressure measuring unit 32 is equal to or greater than a specified value (for example, the pressure difference increases by 10% or more in a specified period of several days to several months) may be identified as a region where ash deposition on the catalyst has progressed relatively.

[0049] In one embodiment, in step S2, the location dependency in the catalyst layer 24 of the performance degradation of the catalyst 26 as the deterioration state of the catalyst 26 is investigated. In this investigation, for example, a region in the catalyst layer 24 where the performance of the catalyst 26 is insufficient and a region where the performance of the catalyst 26 is sufficient are identified. Then, in step S4, based on the investigation of the location dependency in step S2, a region in the catalyst layer 24 where the performance of the catalyst 26 is insufficient is determined as a second region where a second catalyst is used, and a region where the performance of the catalyst 26 is sufficient is determined as a first region where a first catalyst is used. Here, the second catalyst is a catalyst having higher catalytic performance per unit volume than the first catalyst.

[0050] The location dependency of the performance degradation of the catalyst 26 may be investigated by testing the catalytic performance of each of the multiple catalysts 26 constituting the catalytic layer 24 while the combustion equipment 1 is stopped. In this case, a region including a catalyst 26 whose catalytic performance index obtained by the catalytic performance test is less than a specified value may be identified as a region in which the catalytic performance is insufficient.

[0051] In one embodiment, in step S2, the location dependency of the reducing agent leakage amount, the denitration rate, or the SO2 (sulfur dioxide) oxidation rate in the catalyst layer 24 is investigated as an index of the deterioration state of the catalyst 26. Note that the reducing agent leakage amount, the denitration rate, or the SO2 oxidation rate also functions as an index of catalyst performance.

[0052] The reducing agent leakage amount is expressed as the concentration of the reducing agent (ammonia, etc.) at a position downstream of the catalyst layer 24 in the exhaust gas flow direction. The denitration rate is expressed as the ratio of the NOx (nitrogen oxide) concentration at a position downstream of the catalyst layer 24 in the exhaust gas flow direction to the NOx concentration at a position upstream of the catalyst layer 24 in the exhaust gas flow direction. The SO2 oxidation rate is expressed as the ratio of the SO3 (sulfur trioxide) concentration at a position downstream of the catalyst layer 24 in the exhaust gas flow direction to the SO3 concentration at a position upstream of the catalyst layer 24 in the exhaust gas flow direction. The NOx concentration can be measured using a chemiluminescence type NOx meter (JIS B 7982) or by the zinc-reduced naphthylethylenediamine absorptiometry method (Zn-NEDA method) in accordance with JIS K 0104.

[0053] When the amount of reducing agent leakage is used as an indicator of the deterioration state of the catalyst, in step S4, based on the investigation of the location dependency in step S2, a region within catalyst layer 24 where the amount of reducing agent leakage is relatively large is determined as a second region where the second catalyst is used, and a region where the amount of reducing agent leakage is relatively small is determined as a first region where the first catalyst is used.

[0054] The location dependency of the reducing agent leakage amount may be investigated by measuring the reducing agent concentration in the flue 2 during operation of the combustion equipment 1. In this case, the reducing agent concentration (in-plane distribution of the reducing agent concentration downstream of the catalyst layer 24) at the above-mentioned multiple seventh positions is measured by the reducing agent concentration measurement unit 38. Then, among the multiple seventh positions, a region including the catalyst 26 corresponding to a position where the measurement value by the reducing agent concentration measurement unit 38 is equal to or greater than a specified value (e.g., 3 ppm) may be identified as a region where the reducing agent leakage amount is relatively large. The concentration of ammonia (NH3) as a reducing agent can be measured by ion chromatography in accordance with JIS K 0099.

[0055] When the denitration rate is used as an indicator of the deterioration state of the catalyst, in step S4, based on the investigation of the location dependency in step S2, a region within catalyst layer 24 where the denitration rate is relatively low is determined as a second region where the second catalyst is used, and a region where the denitration rate is relatively high is determined as a first region where the first catalyst is used.

[0056] The location dependency of the denitration rate may be investigated by measuring the NOx concentration in the flue 2 during operation of the combustion equipment 1. In this case, the first NOx concentration measurement unit 33 measures the NOx concentration at the above-mentioned multiple third positions, and the second NOx concentration measurement unit 34 measures the NOx agent concentration at the above-mentioned multiple fourth positions. In addition, the denitration rate at each position is calculated based on the NOx concentration measurement values ​​at the corresponding third and fourth positions. Then, a region including the catalyst 26 corresponding to a position where the denitration rate calculated in this way is equal to or lower than a specified value may be identified as a region where the denitration rate is relatively small.

[0057] When the SO2 oxidation rate is used as an indicator of the deterioration state of the catalyst, in step S4, based on the investigation of the location dependency in step S2, a region within catalyst layer 24 where the SO2 oxidation rate is relatively high is determined as a second region where the second catalyst is used, and a region where the SO2 oxidation rate is relatively low is determined as a first region where the first catalyst is used.

[0058] The location dependency of the SO2 oxidation rate may be investigated by measuring the SO3 concentration in the flue 2 while the combustion equipment 1 is in operation. In this case, the first SOx concentration measurement unit 35 measures the SO3 concentration at the above-mentioned multiple fifth positions, and the second SOx concentration measurement unit 36 ​​measures the SO3 agent concentration at the above-mentioned multiple sixth positions. In addition, the SO2 oxidation rate at each position is calculated based on the SO3 concentration measurement values ​​at the corresponding fifth and sixth positions. Then, a region including the catalyst 26 corresponding to a position where the SO2 oxidation rate calculated in this way is equal to or greater than a specified value may be identified as a region where the SO2 oxidation rate is relatively high.

[0059] In some embodiments, the first catalyst is a catalyst having a larger hydraulic diameter of the cells 27 (see FIGS. 3 and 4) than the second catalyst. The hydraulic diameter of the cells 27 of the catalyst can be expressed as (4×A) / L, where L is the perimeter length of the cells 27 and A is the cross-sectional area of ​​the flow path of the cells 27.

[0060] The likelihood of occurrence and progression of certain events associated with catalyst degradation varies depending on the structure of the catalyst, for example, depending on the hydraulic diameter of the cells formed by the catalyst carrier. As described above, by disposing the first catalyst and the second catalyst, whose cells 27 have different hydraulic diameters, in the first region and the second region determined in the above steps S2 to S4, respectively, it is possible to effectively suppress the occurrence and progression of events associated with catalyst degradation. This makes it possible to suppress deterioration in the performance or function of the denitration device 20, and to continuously use the denitration device 20 for a longer period of time.

[0061] In some embodiments, the first catalyst is a plate catalyst 26A and the second catalyst is a honeycomb catalyst 26B.

[0062] The likelihood of occurrence and progression of certain events related to catalyst degradation varies depending on the structure of the catalyst, for example, between plate-shaped catalysts and honeycomb catalysts. In the above-described embodiment, the first catalyst, which is the plate-shaped catalyst 26A, and the second catalyst, which is the honeycomb catalyst 26B, are used, so that by arranging the first catalyst (plate-shaped catalyst 26A) and the second catalyst (honeycomb catalyst 26B) in the first region and the second region determined in steps S2 to S4, respectively, it is possible to effectively suppress the occurrence and progression of events related to catalyst degradation.

[0063] In step S6, at least a portion of the catalyst 26 constituting the catalyst layer 24 is replaced with the first catalyst or the second catalyst so that the first catalyst and the second catalyst are disposed in the first region and the second region determined in the above-mentioned steps S2 to S4, respectively.

[0064] For example, a case will be described in which the first and second regions are determined by the above-mentioned steps S2 to S4 for the catalyst layer 24 composed only of the honeycomb catalyst 26B, and a plate-shaped catalyst is used as the first catalyst and a honeycomb catalyst is used as the second catalyst. In this case, in step S6, each of the catalysts 26 (honeycomb catalysts 26B) located in the first region is replaced with the plate-shaped catalyst 26A, which is the first catalyst. For the catalysts 26 (honeycomb catalysts 26B) located in the second region, the existing honeycomb catalysts 26B may continue to be used as they are as the second catalyst, or all or a part of the existing honeycomb catalysts 26B may be replaced with unused honeycomb catalysts 26B.

[0065] In this manner, at least a portion of the catalyst 26 constituting the catalyst layer 24 is replaced with the first catalyst or the second catalyst so that the first catalyst and the second catalyst are arranged in the first and second regions of the catalyst layer 24 determined in steps S2 to S4, thereby making it possible to suppress the occurrence and progression of events associated with catalyst deterioration.

[0066] In the above-described embodiment, the catalyst arrangement of the denitration device 20 in a certain combustion facility 1 is determined based on the operational record of the combustion facility 1, but in another embodiment, the catalyst arrangement of the denitration device 20 in a combustion facility different from the existing combustion facility (for example, a newly installed combustion facility) may be determined based on the operational record of the existing combustion facility. The latter embodiment will be described below.

[0067] FIG. 7 is a flowchart of a catalyst arrangement determination method for a denitration device according to one embodiment.

[0068] 7, in one embodiment, first, after the operation period of the denitration device 20 (investigative denitration device) in the existing first combustion equipment has elapsed (i.e., after the operation period of the first combustion equipment including the investigative denitration device has elapsed), the location dependency of the deterioration state of the catalyst 26 in the catalyst layer 24 of the denitration device 20 (investigative denitration device) is investigated (S12). The method of investigating the location dependency of the deterioration state of the catalyst 26 is similar to the above-mentioned step S2.

[0069] Next, in step S14, an area suitable for use of the first catalyst and an area suitable for use of a second catalyst different from the first catalyst are determined in the catalyst layer 24 in the denitration device 20 of the first combustion facility (investigative denitration device) based on the results of the investigation into the location dependency of the deterioration state of the catalyst 26 in step S12. Also, for the catalyst layer 24 of the denitration device 20 in the second combustion facility, which is a combustion facility different from the first combustion facility, a first area corresponding to the area suitable for use of the first catalyst described above is determined, and a second area corresponding to the area suitable for use of the second catalyst described above is determined.

[0070] Then, in step S16, in the catalyst layer 24 of the denitration device 20 of the second combustion facility, a first catalyst is installed in the first region determined in steps S12 to S14, and a second catalyst is installed in the second region determined in steps S12 to S14.

[0071] According to the above-mentioned embodiment, the location dependency of the deterioration state of the catalyst 26 in the catalyst layer 24 of the investigation denitration device is investigated, and the first and second regions of the catalyst layer 24 of the denitration device 20 other than the investigation denitration device are determined based on the location dependency. That is, the first and second regions can also be determined for the denitration device 20 in a new plant (second combustion equipment) that has no operating history, based on the operating history of the existing investigation denitration device. Therefore, even in the new plant, the occurrence and progression of events related to catalyst deterioration can be suppressed by arranging the first and second catalysts in the first and second regions determined as described above. Therefore, the deterioration of the performance or function of the denitration device 20 can be suppressed, and the denitration device can be used continuously for a longer period of time.

[0072] The contents described in each of the above embodiments can be understood, for example, as follows.

[0073] (1) A method for determining catalyst arrangement in a denitration apparatus according to at least one embodiment of the present invention includes the steps of: 1. A method for determining catalyst placement in a denitration device (20) including a catalyst layer (24) provided in an exhaust gas flow path, comprising: a step (S2) of investigating location dependency of a deterioration state of the catalyst (26) in the catalyst layer after an operating period has elapsed; determining (S4) a first region of the catalyst layer using a first catalyst and a second region of the catalyst layer using a second catalyst different from the first catalyst based on the location dependence; Equipped with.

[0074] In a denitration device including a catalyst layer made of a catalyst, certain events related to catalyst deterioration (e.g., catalyst wear or ash deposition on the catalyst) are likely to occur in certain regions of the catalyst layer. In addition, the likelihood of occurrence and progression of such events differs depending on the type of catalyst. In this regard, according to the method of (1) above, the location dependency of the catalyst deterioration state in the catalyst layer is investigated, and the first and second regions of the catalyst layer that use different first and second catalysts, respectively, are determined based on the location dependency. Therefore, if the first and second catalysts are appropriately selected, the occurrence and progression of events related to catalyst deterioration can be suppressed by arranging the first and second catalysts in the catalyst layer according to this determination. Therefore, it is possible to suppress the deterioration of the performance or function of the denitration device, and it is possible to continue using the denitration device for a longer period of time.

[0075] (2) In some embodiments, in the method of (1), the first catalyst and the second catalyst each have cells (32) extending along a flow direction of exhaust gas; The hydraulic diameter of the cells of the first catalyst is greater than the hydraulic diameter of the cells of the second catalyst.

[0076] The likelihood of occurrence and progression of certain events associated with catalyst degradation varies depending on the structure of the catalyst, for example, depending on the hydraulic diameter of the cells formed by the catalyst carrier. According to the method (2) above, a first catalyst and a second catalyst having different hydraulic diameters of cells formed by the carrier are used, and by disposing the first catalyst and the second catalyst in the first region and the second region determined by the method (1) above, respectively, the occurrence and progression of events associated with catalyst degradation can be effectively suppressed. This makes it possible to suppress the deterioration of the performance or function of the denitration device, and to continuously use the denitration device for a longer period of time.

[0077] (3) In some embodiments, in the method of (1) or (2), the first catalyst is a plate-shaped catalyst (26A), The second catalyst is a honeycomb catalyst (26B).

[0078] The likelihood of occurrence and progression of certain events related to catalyst degradation varies depending on the structure of the catalyst, for example, between plate-type catalysts and honeycomb catalysts. According to the method of (3) above, a first catalyst which is a plate-type catalyst and a second catalyst which is a honeycomb catalyst are used, and by disposing the first catalyst (plate-type catalyst) and the second catalyst (honeycomb catalyst) in the first region and the second region determined by the method of (1) above, respectively, the occurrence and progression of events related to catalyst degradation can be effectively suppressed. This makes it possible to suppress deterioration in the performance or function of the denitration device, and to continuously use the denitration device for a longer period of time.

[0079] (4) In some embodiments, in any of the methods (1) to (3) above, In the investigating step, the deterioration state is investigated, which may be a wear state of the catalyst, a state of ash deposition on the catalyst, a performance decrease of the catalyst, or location dependency of the amount of reducing agent leaking from the catalyst.

[0080] According to the method of (4) above, the location dependency of the catalyst deterioration state, such as the wear state of the catalyst, the state of ash deposition on the catalyst, the performance degradation of the catalyst, or the amount of reducing agent leaking from the catalyst, is investigated. Therefore, based on the results of the investigation of the location dependency, the first and second regions of the catalyst layer using the different first and second catalysts, respectively, can be appropriately determined. Therefore, by arranging the first and second catalysts in the catalyst layer according to this determination, the deterioration of the catalyst can be suppressed. Therefore, the deterioration of the performance or function of the denitration device can be suppressed, and the denitration device can be used continuously for a longer period of time.

[0081] (5) In some embodiments, in the method of (4), In the step of investigating, location dependency of a wear state of the catalyst as the deterioration state is investigated; The first region is a region where the catalyst is more worn than the second region.

[0082] According to the method of (5) above, the first catalyst is disposed in the first region where catalyst wear is relatively advanced, and the second catalyst is disposed in the second region where catalyst wear is relatively advanced, so that by using a catalyst that is relatively resistant to wear as the first catalyst, it is possible to effectively suppress catalyst wear in the first region. This makes it possible to effectively suppress deterioration in the performance or function of the denitration device, and enables the denitration device to be used continuously for a longer period of time.

[0083] (6) In some embodiments, in the method of (4), In the step of investigating, location dependency of an ash deposition state on the catalyst is investigated as the deterioration state; The first region is a region in which an area where clogging of the catalyst occurs is larger than that of the second region when viewed from a direction perpendicular to the exhaust gas flow direction.

[0084] According to the method (6) above, the first catalyst is disposed in the first region where ash accumulation and the resulting clogging of the catalyst are relatively advanced, and the second catalyst is disposed in the second region where ash accumulation and the clogging of the catalyst are relatively advanced, so that by using a catalyst on which ash is relatively unlikely to accumulate as the first catalyst, ash accumulation on the catalyst in the first region can be effectively suppressed. This effectively suppresses deterioration of the performance or function of the denitration device, and enables the denitration device to be used continuously for a longer period of time.

[0085] (7) In some embodiments, in the method of (4), In the step of investigating, location dependency of the performance deterioration of the catalyst is investigated as the deterioration state; The second region is a region where the performance of the catalyst is lower than that of the first region.

[0086] According to the above method (7), the second catalyst is disposed in the second region where catalyst performance degradation has progressed relatively, and the first catalyst is disposed in the first region where catalyst performance degradation has not progressed relatively. Therefore, by using a catalyst with relatively high catalytic performance (denitrification performance) per unit volume as the second catalyst, it is possible to expect improved catalytic performance with the same volume.

[0087] (8) In some embodiments, in the method of (4), In the step of investigating, a location dependency of a reducing agent leakage amount as the deterioration state is investigated; The second region is a region in which the amount of the reducing agent leakage is greater than that in the first region.

[0088] According to the method of (8) above, the second catalyst is arranged in the second region where the amount of reducing agent leakage is relatively large, and the first catalyst is arranged in the first region where the amount of reducing agent leakage is relatively small, so that the amount of reducing agent leakage in the second region can be effectively reduced by adopting a catalyst with relatively high catalytic performance (denitrification performance) per unit volume as the second catalyst. Therefore, the deterioration of the performance or function of the denitrification device can be effectively suppressed, and the denitrification device can be used continuously for a longer period of time.

[0089] (9) A method for maintaining a denitrification apparatus according to at least one embodiment of the present invention includes the steps of: A step (S6) of replacing at least a part of the catalyst constituting the catalyst layer with the first catalyst or the second catalyst so that the first catalyst and the second catalyst are arranged in the first region and the second region, respectively, determined by the catalyst arrangement determination method according to any one of (1) to (8) above. Equipped with.

[0090] According to the method of (9) above, at least a part of the catalyst constituting the catalyst layer is replaced with the first catalyst or the second catalyst so that the first catalyst and the second catalyst are arranged in the first and second regions of the catalyst layer determined by the method of (1) above, so that the occurrence and progression of events related to catalyst deterioration can be suppressed. Therefore, the deterioration of the performance or function of the denitration device can be suppressed, and the denitration device can be used continuously for a longer period of time.

[0091] (10) A method for determining catalyst arrangement in a denitration apparatus according to at least one embodiment of the present invention includes the steps of: A method for determining a catalyst arrangement for a denitration device provided in an exhaust gas flow passage, comprising: After an operating period of a plant in which a survey-use denitration device other than the denitration device is installed has elapsed, a step (S12) of investigating the location dependency of a deterioration state of a catalyst in a catalyst layer of the survey-use denitration device; determining (S14) a first region of a catalyst layer of the denitration device that uses a first catalyst and a second region of a catalyst layer of the denitration device that uses a second catalyst different from the first catalyst based on the location dependency; Equipped with.

[0092] In the method of (10) above, the location dependency of the deterioration state of the catalyst in the catalyst layer of the investigation denitration device is investigated, and the first and second regions of the catalyst layer of a denitration device other than the investigation denitration device are determined based on the location dependency. That is, even for a denitration device in a new plant with no operating history, the first and second regions can be determined based on the operating history of the existing investigation denitration device. Therefore, according to the operating method of (10) above, even in a new plant, the occurrence and progression of events related to catalyst deterioration can be suppressed by arranging the first and second catalysts in the first and second regions determined as described above. Therefore, the deterioration of the performance or function of the denitration device can be suppressed, and the denitration device can be used continuously for a longer period of time.

[0093] (11) A denitration device according to at least one embodiment of the present invention comprises: A catalyst layer is provided in an exhaust gas flow path, The catalyst layer includes a first region of the catalyst layer that uses a first catalyst and a second region of the catalyst layer that uses a second catalyst different from the first catalyst, the first region and the second region of the catalyst layer being determined based on the location-dependence of the deterioration state of the catalyst in the catalyst layer after an operating period has elapsed.

[0094] According to the above configuration (11), the location dependency of the deterioration state of the catalyst in the catalyst layer is investigated, and the first and second regions of the catalyst layer using the different first and second catalysts, respectively, are determined based on the location dependency. Therefore, if the first and second catalysts are appropriately selected, the occurrence and progression of events related to catalyst deterioration can be suppressed by arranging the first and second catalysts in the catalyst layer according to this determination. Therefore, it is possible to suppress the deterioration of the performance or function of the denitration device, and it is possible to continue using the denitration device for a longer period of time.

[0095] (12) A boiler according to at least one embodiment of the present invention comprises: a combustion device for combusting fuel; an exhaust gas flow path through which exhaust gas from the combustion device is guided; The denitration device according to (11) above, which includes a catalyst layer provided in the exhaust gas flow path; Includes.

[0096] (13) A power generation plant according to at least one embodiment of the present invention comprises: The boiler according to (12) above; a generator configured to be driven by steam generated in the boiler; Equipped with.

[0097] (14) A denitration device according to at least one embodiment of the present invention comprises: A denitration device having a catalyst layer provided in an exhaust gas flow path, The catalyst layer includes a first region of the catalyst layer using a first catalyst and a second region of the catalyst layer using a second catalyst different from the first catalyst, each of which is determined based on the location-dependence of the deterioration state of the catalyst in the catalyst layer of the research denitration device after an operating period of a plant in which a research denitration device separate from the denitration device is installed.

[0098] In the above configuration (14), the location dependency of the deterioration state of the catalyst in the catalyst layer of the investigation denitration device is investigated, and the first and second regions of the catalyst layer of a denitration device other than the investigation denitration device are determined based on the location dependency. That is, even for a denitration device in a new plant with no operating history, the first and second regions can be determined based on the operating history of the existing investigation denitration device. Therefore, according to the above configuration (14), even in a new plant, the occurrence and progression of events related to catalyst deterioration can be suppressed by arranging the first and second catalysts in the first and second regions determined as described above. Therefore, the deterioration of the performance or function of the denitration device can be suppressed, and the denitration device can be used continuously for a longer period of time.

[0099] (15) A boiler according to at least one embodiment of the present invention comprises: a combustion device for combusting fuel; an exhaust gas flow path through which exhaust gas from the combustion device is guided; The denitration device according to (14) above, which includes a catalyst layer provided in the exhaust gas flow path; Includes.

[0100] (16) A power generation plant according to at least one embodiment of the present invention comprises: The boiler according to (15) above; a generator configured to be driven by steam generated in the boiler; Equipped with.

[0101] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and also includes modifications to the above-described embodiments and appropriate combinations of these modifications.

[0102] In this specification, expressions expressing relative or absolute configuration, such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial," do not only strictly express such a configuration, but also express a state in which there is a relative displacement with a tolerance or an angle or distance to the extent that the same function is obtained. For example, expressions indicating that things are in an equal state, such as "identical," "equal," and "homogeneous," not only indicate a state of strict equality, but also indicate a state in which there is a tolerance or a difference to the extent that the same function is obtained. Furthermore, in this specification, expressions describing shapes such as a rectangular shape or a cylindrical shape do not only refer to shapes such as a rectangular shape or a cylindrical shape in the strict geometric sense, but also refer to shapes that include uneven portions, chamfered portions, etc., to the extent that the same effect can be obtained. In addition, in this specification, the expressions "comprise," "include," or "have" a certain element are not exclusive expressions that exclude the presence of other elements. [Explanation of symbols]

[0103] 1 Combustion equipment 2 Flue 2a Part 1 2b 2nd part 2c downstream part 4 Exhaust gas flow path 8. Chimney 10 Heater 20 Denitration equipment 22 Reducing agent supply unit 24 Catalyst layer 24a Upstream end 24b Downstream end 26 Catalyst 26A Plate-shaped catalyst 26B Honeycomb catalyst 27 Cell 28 Carrier 29 Board part 30 Support part 31 First pressure measurement section 32 Second pressure measurement section 33 First NOx concentration measurement unit 34 Second NOx concentration measurement unit 35 First SOx concentration measurement section 36 Second SOx concentration measurement section 38 Reducing agent concentration measurement unit A Flow sectional area L Circumference length

Claims

1. A method for determining catalyst arrangement in a denitration device including a catalyst layer provided in an exhaust gas flow passage, comprising: investigating the location dependency of a deterioration state of the catalyst in the catalyst layer after an operating period has elapsed; Based on the location dependency, determining a first region of the catalyst layer using a first catalyst and a second region of the catalyst layer using a second catalyst having at least one of durability, ash permeability, pressure drop, and wear resistance different from that of the first catalyst; Equipped with The first region is a region in which the deterioration of the catalyst has progressed more than that of the second region, The first catalyst is a catalyst that is less susceptible to deterioration than the second catalyst. A method for determining catalyst placement in a denitration device.

2. The first catalyst and the second catalyst each have cells extending along a flow direction of exhaust gas, The hydraulic diameter of the cells of the first catalyst is greater than the hydraulic diameter of the cells of the second catalyst. The method for determining catalyst arrangement in a denitration device according to claim 1 .

3. The first catalyst is a plate-shaped catalyst, The second catalyst is a honeycomb catalyst. The method for determining catalyst arrangement in a denitration device according to claim 1 or 2.

4. In the step of investigating, the deterioration state is investigated to see whether the catalyst is worn, whether ash has accumulated on the catalyst, whether the catalyst has a deteriorated performance, or whether the amount of reducing agent leaking from the catalyst is location-dependent. The method for determining a catalyst arrangement in a denitration device according to any one of claims 1 to 3.

5. In the step of investigating, location dependency of a wear state of the catalyst as the deterioration state is investigated; The first region is a region where the catalyst is more worn than the second region. The method for determining the catalyst arrangement in a denitration device according to claim 4.

6. In the step of investigating, a location dependency of an ash deposition state on the catalyst is investigated as the deterioration state; The first region is a region in which an area where the catalyst is clogged is larger than that of the second region when viewed in the exhaust gas flow direction. The method for determining the catalyst arrangement in a denitration device according to claim 4.

7. In the step of investigating, location dependency of the performance deterioration of the catalyst is investigated as the deterioration state; The second region is a region in which the performance of the catalyst is lower than that of the first region. The method for determining a catalyst arrangement in a denitration device according to claim 4.

8. In the step of investigating, a location dependency of a reducing agent leakage amount as the deterioration state is investigated; The second region is a region in which the amount of the reducing agent leak is larger than that in the first region. The method for determining a catalyst arrangement in a denitration device according to claim 4.

9. In the determining step, A range of the first region in a first direction and a range of the first region in a second direction perpendicular to the first direction are determined in a plane perpendicular to the exhaust gas flow direction; determining an extent in the first direction and an extent in the second direction of the second region within the plane; The method for determining a catalyst arrangement in a denitration device according to any one of claims 1 to 8.

10. A step of replacing at least a part of the catalyst constituting the catalyst layer with the first catalyst or the second catalyst so that the first catalyst is arranged in the first region and the second catalyst is arranged in the second region determined by the catalyst arrangement determination method according to any one of claims 1 to 9. A maintenance method for a denitrification device comprising:

11. A method for determining a catalyst arrangement for a denitration device provided in an exhaust gas flow passage, comprising: A step of investigating location dependency of a deterioration state of a catalyst in a catalyst layer of the investigation denitration device after an operating period of a plant in which an investigation denitration device other than the denitration device is installed has elapsed; determining a first region of a catalyst layer of the denitration device using a first catalyst and a second region of a catalyst layer of the denitration device using a second catalyst that is different from the first catalyst in at least one of durability, ash permeability, pressure drop, and wear resistance, based on the location dependency; Equipped with The first region is a region in which the deterioration of the catalyst has progressed more than that of the second region, The first catalyst is a catalyst that is less susceptible to deterioration than the second catalyst. A method for determining catalyst placement in a denitration device.

12. A method for manufacturing a denitration device having a catalyst layer provided in an exhaust gas flow passage, comprising: The catalyst layer includes a first region using a first catalyst, and a second region using a second catalyst having at least one of durability, ash permeability, pressure drop, and abrasion resistance different from that of the first catalyst, determining the first region and the second region based on location dependency of a deterioration state of a catalyst in the catalyst layer after an operating period has elapsed; disposing the first catalyst in the first region and disposing the second catalyst in the second region; Equipped with The first region is a region in which the deterioration of the catalyst has progressed more than that of the second region, The first catalyst is a catalyst that is less susceptible to deterioration than the second catalyst. A method for manufacturing a denitration device.

13. a combustion device for combusting fuel; an exhaust gas flow path through which exhaust gas from the combustion device is guided; a denitration device including a catalyst layer provided in the exhaust gas flow path; A method for manufacturing a boiler comprising the steps of: The method includes the step of manufacturing the denitration device by the method according to claim 12. A method for manufacturing a boiler.

14. A boiler, a generator configured to be driven by steam generated in the boiler; A method for manufacturing a power plant comprising: The method includes the step of manufacturing the boiler by the method according to claim 13. A method for manufacturing a power plant.

15. A method for manufacturing a denitration device having a catalyst layer provided in an exhaust gas flow passage, comprising: The catalyst layer includes a first region using a first catalyst, and a second region using a second catalyst having at least one of durability, ash permeability, pressure drop, and abrasion resistance different from that of the first catalyst, determining the first and second regions based on location dependency of a deterioration state of a catalyst in a catalyst layer of the investigation denitration device after an operating period of a plant in which the investigation denitration device is provided, the investigation denitration device being different from the denitration device; disposing the first catalyst in the first region and disposing the second catalyst in the second region; Equipped with The first region is a region in which the deterioration of the catalyst has progressed more than that of the second region, The first catalyst is a catalyst that is less susceptible to deterioration than the second catalyst. A method for manufacturing a denitration device.

16. a combustion device for combusting fuel; an exhaust gas flow path through which exhaust gas from the combustion device is guided; a denitration device including a catalyst layer provided in the exhaust gas flow path; A method for manufacturing a boiler comprising the steps of: The method includes the step of manufacturing the denitration device by the method according to claim 15. A method for manufacturing a boiler.

17. A boiler, a generator configured to be driven by steam generated in the boiler; A method for manufacturing a power plant comprising: The method includes the step of manufacturing the boiler by the method according to claim 16. A method for manufacturing a power plant.

Images