SEALING STRUCTURE, HEAT RECOVERY STEAM GENERATOR, AND EXHAUST FUME SEALING METHOD

Abstract

The aim is to reduce the amount of undentiated exhaust gas flowing downstream of an exhaust gas denitrifier. A sealing structure (20) is the sealing structure (20) that seals a gap formed between a channel (2) through which exhaust gas flows and an exhaust gas denitrifier (6) arranged in the channel (2). The sealing structure (20) comprises: a sealing device (22) fixed to the channel (2) and arranged in a gap; a sealing plate (23) fixed to the exhaust gas denitrifier (6), arranged in the gap, and abutting or near the sealing device (22); and a first plate-type catalyst (24) fixed to the exhaust gas denitrifier (6), arranged in the gap, and configured to press the sealing device (22) against the sealing plate (23). The first plate-type catalyst (24) is formed from a denitrification catalyst.

Description

[Technical field]

[0001] The present disclosure includes a sealing structure, a heat recovery steam generator, and an exhaust gas sealing method. [Background information]

[0002] In heat recovery steam generators (HRSGs), the exhaust gas emitted by a gas turbine or similar plant is channeled through a duct, and heat is exchanged between the exhaust gas and water or steam in heat transfer tubes to generate steam. Within the duct of a heat recovery steam generator, a plurality of heat exchangers with a number of heat transfer tubes through which water or steam flows, a flue gas denitrifier that removes nitrogen oxides (NOx) in the exhaust gas, and the like are installed.

[0003] A gap is formed between an exhaust gas denitrifier and a duct that accommodates the exhaust gas denitrifier. In this gap, a short exhaust gas path (that is, an exhaust gas flows downstream of an exhaust gas denitrifier without passing through the exhaust gas denitrifier) ​​may occur. To suppress the occurrence of a short exhaust gas path, the gap can be provided with a sealing structure (e.g., Patent Literature 1).

[0004] Patent Literature 1 discloses a heat recovery steam generator in which the lower group of heat transfer tubes, an exhaust gas denitrifier (catalyst), and the upper group of heat transfer tubes are arranged within a casing at predetermined intervals from bottom to top. Furthermore, in this device, an elastically deformable member is arranged between the inner surface of the casing and the exhaust gas denitrifier. The member connects a horizontal flange fixed to the entire periphery of the inner wall of the casing with a connecting flange fixed to the entire periphery of the lower outer part of a flame body. [Citation list][Patent literature]

[0005] [PTL 1] Japanese Patent Application Laid-Open No. 2014-178103 [Summary of the invention][Technical problem]

[0006] In recent years, power generation plants using hydrogen or ammonia as fuel have attracted attention in terms of reducing greenhouse gas emissions. However, when using hydrogen or ammonia as fuel, the amount of nitrogen oxides (NOx) generated is expected to increase significantly compared to conventional fuels such as coal. Therefore, to reduce NOx emissions in power plants using hydrogen or ammonia as fuel, it is necessary to more effectively suppress the occurrence of a short exhaust path. From this perspective, a technology that can more effectively suppress the occurrence of short circuits in the exhaust gas is desirable.

[0007]

[0007] Because high-temperature exhaust gas flows through the casing, the casing and the exhaust gas denitrifier are heated and thermally expanded by the heat of the exhaust gas. In addition, thermal insulation materials are applied to the outer peripheral surface or inner peripheral surface of the casing to prevent the heat of the exhaust gas from being transferred to the outside. When thermal insulation materials are applied to the outer peripheral surface of the casing (hereinafter referred to as the "external thermal insulation mold"), the gap formed between the casing and the exhaust gas denitrifier is also small because the temperature difference and thermal expansion difference between the casing and the exhaust gas denitrifier are small.In contrast, when thermal insulation materials are attached to the inner peripheral surface of the casing (hereinafter referred to as "inner thermal insulation mold"), the gap formed between the casing and the exhaust gas denitrifier is also larger because the temperature difference and thermal expansion difference between the casing and the exhaust gas denitrifier are larger.

[0008] As mentioned above, although a gap is formed between the casing and the exhaust gas denitrifier when using both the external and internal insulation forms, the gap formed between the casing and the exhaust gas denitrifier tends to be larger when using the internal insulation form. Therefore, the amount of exhaust gas that travels a shorter path tends to be larger.

[0009] Furthermore, as in the device disclosed in Patent Document 1, in a duct of the vertical flow system in which an exhaust gas flows vertically, the duct and the exhaust denitrifier thermally expand vertically from a load-bearing point as the base point and thermally expand horizontally uniformly around the center axis of the duct. Thus, the clearance formed between the casing and the exhaust denitrifier is substantially uniform over the entire circumference. In contrast, in a duct of the horizontal flow system in which an exhaust gas flows horizontally, since the duct and the exhaust denitrifier thermally expand in an expansion direction from the bottom surface, which is the load-bearing point, the displacement difference between a part near the bottom surface and a part near the ceiling is greatly different.Thus, the space formed between the housing and the exhaust gas denitrifier is not substantially uniform over its entire circumference.

[0010] The sealing structure disclosed in Patent Document 1 is fixed to the duct and the exhaust gas denaturer. Therefore, when the sealing structure described in Patent Document 1 is applied to the duct of the horizontal flow system, the displacement difference between a part near the floor surface and a part near the ceiling will cause different deformation of the element, and a part of the sealing element with a large degree of deformation is likely to be worn or damaged. When the element seals or is damaged, the sealing performance at the damaged part or parts is reduced, the exhaust gas takes a short path, and thus the amount of exhaust gas taking the short path may increase.

[0011] As described above, although a gap or gap forms between the casing and the exhaust gas denitrifier in both cases where the vertical flow system duct is used and the horizontal flow system duct is used, the case where the horizontal flow system duct is used tends to cause a displacement difference of the duct or the like over the entire circumference. Therefore, the amount of exhaust gas traveling in a short path tends to be larger.

[0012] As described above, although a short path can occur in all outer thermal insulation molds, the inner thermal insulation mold, the channel of the vertical flow system and the channel of the horizontal flow system, a short path of a flow gas can be particularly amplified in the inner thermal insulation mold or the horizontal flow system.

[0013] The present disclosure has been made in view of such circumstances and intends to provide a sealing structure, a heat recovery steam generator, and an exhaust gas sealing method that can reduce the amount of non-denitrified exhaust gas passing downstream of an exhaust gas denitrifier.

[0014] In particular, the present disclosure intends to provide a sealing structure, a heat recovery steam generator, and an exhaust gas sealing method that can effectively reduce the amount of non-denitrified exhaust gas flowing downstream of an exhaust gas denitrifier in a case of the internal heat insulation mold or the horizontal flow system. [Solution to the problem]

[0015] In order to solve the above problem, the following solutions are used in a sealing structure, a heat recovery steam generator, and an exhaust gas sealing method of the present disclosure.

[0016] The sealing structure according to one aspect of the present disclosure is a sealing structure configured to seal a gap formed between a duct through which an exhaust gas flows and an exhaust gas denitrifier disposed in the duct, the sealing structure comprising at least one duct-side sealing part fixed to the duct and disposed in the gap; an exhaust gas denitrifier-side sealing part.a sealing member disposed on the exhaust gas denitrifier side, fixed to the exhaust gas denitrifier and disposed in the gap, and abutting or close to the passage-side sealing member; and a first catalyst sealing member fixed to the exhaust gas denitrifier and disposed in the gap, configured to press the passage-side sealing member against the exhaust gas denitrifier-side sealing member, the first catalyst sealing member being formed of a denitrification catalyst.

[0017] The exhaust gas sealing method according to one aspect of the present disclosure is an exhaust gas sealing method using a sealing structure configured to seal a gap formed between a passage through which an exhaust gas flows and an exhaust denitrifier disposed in the passage, the sealing structure comprising: a passage-side sealing part fixed to the passage and disposed in the gap, an exhaust denitrifier-side sealing part fixed to the exhaust denitrifier, disposed in the gap, and abutting against or near the passage-side sealing part, and a first catalyst sealing part fixed to the exhaust denitrifier, disposed in the gap, and configured to press the passage-side sealing part against the exhaust denitrifier-side sealing part, the first catalyst sealing part being formed from a denitrification catalyst,and wherein the exhaust gas sealing method comprises: sealing a gap formed between the duct and the exhaust gas denitrifier using the duct-side sealing part, the exhaust gas denitrifier-side sealing part, and the first catalyst sealing part. [Advantageous effects of the invention]

[0018] According to the present disclosure, the amount of non-denitrified exhaust gas passing downstream of an exhaust denitrifier can be reduced.

[0019] In particular, the amount of non-denitrified exhaust gas flowing downstream of an exhaust denitrifier can be effectively reduced in the case of the internal thermal insulation mold or the horizontal flow system. [Brief description of the drawings] [ Fig. 1] Fig. 1 is a configuration diagram showing a heat recovery steam generator according to a first embodiment of the present disclosure. [ Fig. 2] Fig. 2 is a perspective view illustrating a NOx removal system and a sealing structure according to the first embodiment of the present disclosure. [ Fig. 3] Fig. 3 is a sectional view showing the sealing structure according to the first embodiment of the present disclosure. [ Fig. 4] Fig. 4 is a diagram showing a modified example of Fig. 3 shows. [ Fig. 5] Fig. Figure 5 is a diagram showing a modified example of Fig. 3 illustrated. [ Fig. 6] Fig. 6 is a perspective view showing an exhaust denitrifier and a sealing structure according to a second embodiment of the present disclosure. [ Fig. 7] Fig. 7 is a perspective view showing an exhaust gas denitrifier and a sealing structure according to a third embodiment of the present disclosure. [Description of the embodiments]

[0020] A sealing structure, a heat recovery steam generator, and an exhaust gas sealing method according to embodiments of the present disclosure will be described below with reference to Fig. 1 to Fig. 7. In the following description and the drawings, the vertical direction is referred to as the Z-axis direction, a direction of the horizontal directions through which an exhaust gas flows is referred to as the X-axis direction, and the direction orthogonal to the X-axis direction and the Z-axis direction is referred to as the Y-axis direction. Furthermore, the flow direction of the exhaust gas in the Fig. 1 to Fig. 7 marked by arrow E. [First embodiment]

[0021] A first embodiment of the present disclosure will be described below with reference to the Fig. 1 to Fig. 5 described.

[0022] First, a heat recovery steam generator according to the present embodiment will be described with reference to Fig. 1 described.

[0023] As in Fig. As shown in Figure 1, a heat recovery steam generator 1 according to the present embodiment is a horizontal heat recovery steam generator in which an exhaust gas flows in a horizontal direction. In the present embodiment, the direction of the exhaust gas flow is the horizontal direction, the orthogonal direction is the vertical direction, and the longitudinal direction of a heat transfer tube is the vertical direction.

[0024] As in Fig. As shown in Figure 1, the heat recovery steam generator 1 according to the present embodiment includes heat exchange units 5, such as an economizer, an evaporator, a superheater, or the like, an exhaust gas denitrifier 6, and the like, within a duct 2 that is installed horizontally and expands. A high-temperature combustion exhaust gas (exhaust gas or flue gas) discharged from a gas turbine or the like is introduced into the duct 2 via a duct inlet 3, sequentially passes through the plurality of heat exchange units 5, and is then discharged from a chimney (not shown) via a duct outlet 4. As shown in Fig. 2, the channel 2 has thermal insulation materials 7 which are provided substantially over the entire area of ​​the inner peripheral surface.

[0025] As in Fig. As shown in Figure 1, the heat exchanger units 5 each have a plurality of heat transfer tubes (not shown) extending vertically and intersecting the direction of the exhaust gas flow. Furthermore, distributors (not shown) are provided within the duct 2, connecting a plurality of heat transfer tubes to each other, and a drum 9 is provided outside the duct 2. Each of the distributors is connected to the drum 9 via a connecting pipe (not shown).

[0026] The heat exchanger units 5 recover the heat from an exhaust gas through heat exchange between a heat medium (e.g., water or steam) flowing inside the heat transfer tubes and the exhaust gas. The heat medium, heated by the heat of the exhaust gas, is fed to the drum 9 via the distributor and the connecting pipe.

[0027] Hereinafter, details of the exhaust denitrifier 6 and a sealing structure 20 according to the present embodiment will be described with reference to Fig. 2 to Fig. 5. It should be noted that in the following description, when simply referring to "central side" and "outer side", the "central side" and the "outer side" are meant relative to the central axis of channel 2.

[0028] As in Fig. 2, the exhaust gas denitrifier 6 according to the present embodiment includes a plurality of catalyst packs 11 that remove nitrogen oxides contained in an exhaust gas (denitrify the exhaust gas), a support frame 12 that supports each catalyst pack 11 from below, a plurality of leg members (not shown) that are erected on the bottom surface of the duct 2 and support the support frame 12 from below, and walls 13 that cover the side surfaces of the catalyst packs 11 in the Y-axis direction.

[0029] The plurality of catalyst packs 11 are aligned to cover substantially the entire area of ​​the flow channel cross-section (the cross-section defined by the Z-axis direction and the Y-axis direction) of the channel 2. Note that in the present embodiment, a plurality of catalyst packs 11 are provided in the Z-axis direction and a plurality of catalyst packs 11 are provided in the Y-axis direction. Each catalyst pack 11 is arranged on top of the support frame 12.

[0030] For example, each catalyst package 11 includes a rectangular-cylindrical rectangular frame member (not shown) and a plurality of catalysts (not shown) provided within the rectangular frame member. Examples of the shape of the catalyst include, but are not limited to, a honeycomb shape or a corrugated plate shape. The catalyst promotes a reduction reaction of NOx (nitrogen oxides) contained in an exhaust gas (combustion gas or flue gas) flowing through its interior and removes at least a portion of the NOx. The catalyst component is based on, for example, titanium oxide.

[0031] The support frame 12 has first support beams 12a extending in the Y-axis direction and second support beams 12b extending in the X-axis direction. The first support beams 12a and the second support beams 12b are each a long member, so-called die steel and die steel, respectively, whose cross section, when cut along a plane orthogonal to the extension direction, has a shape such as a substantially H-shape, a substantially C-shape, or the like. The majority of the first support beams 12a are aligned at predetermined intervals along the X-axis. The majority of the second support beams 12b are aligned at predetermined intervals in the Y-axis direction. The support frame 12 provided in the lower row is supported from below by parts of the legs.

[0032] The walls 13 are constructed on top of the support frame 12. The end of each wall 13 in the X-axis direction is provided with a flange portion 13a extending in the Y-axis direction. The wall 13 is provided between the catalyst packs 11 arranged adjacently in the Y-axis direction. Further, the wall 13 arranged at the outermost end in the Y-axis direction is provided between the catalyst pack 11 and the inner peripheral surface of the channel 2 so as to face the inner peripheral surface of the channel 2. A gap G is formed between the wall 13 arranged rearmost in the Y-axis direction and the inner peripheral surface of the channel 2.

[0033] Furthermore, gaps G are also formed between the bottom surface of the catalyst package 11 arranged in the lower row and the inner peripheral surface of the channel 2 and between the upper surface of the catalyst package 11 arranged in the upper row and the inner peripheral surface of the channel 2.

[0034] The gap G formed between the wall 13 located rearmost in the Y-axis direction and the inner peripheral surface of the passage 2 is provided with the sealing structure 20, which seals the gap G so that no exhaust gas flow flows therein. Furthermore, the sealing structure 20, which seals the gap G so that no exhaust gas flows therein, is also provided in the gap G formed between the bottom surface of the catalyst pack 11 arranged in the lower row and the inner peripheral surface of the passage 2, and between the upper surface of the catalyst pack 11 arranged in the upper row and the inner peripheral surface of the passage 2. The sealing structure 20 suppresses the occurrence of a short path of the exhaust gas (that the exhaust gas flows to the downstream of the exhaust denitrifier 6 without passing through the exhaust denitrifier 6) by sealing the gap G.

[0035] As in Fig. 2 and Fig. 3, the sealing structure 20 includes seal mounting strips 21 fixed to the inner peripheral surface of the duct 2 and protruding from the inner peripheral surface toward the center side; and a plurality of seal devices (duct-side seal parts) 22 fixed to the center-side end of the seal mounting strips 21. Furthermore, the sealing structure 20 includes: seal plates (exhaust denitrifier-side seal parts) 23 fixed to the walls 13 and / or the support frame 12 and protruding outward from the walls 13 and / or the support frame 12; and a plurality of first plate-type catalysts (first catalyst seal parts) 24 fixed to the upstream side of the seal plates 23.

[0036] Each seal mounting strip 21 is a plate-shaped member and is fixed substantially over the entire circumference of the inner peripheral surface of the duct 2. Each seal mounting strip 21 protrudes from the inner peripheral surface of the duct 2. The outer end of the seal mounting strip 21 is embedded in the thermal insulation material 7. The central end of the seal mounting strip 21 is located at a position of the gap G, as viewed from the duct inlet 3 side. The central end of the seal mounting strip 21 is provided with an angled flange portion 21a extending in the flow direction. The sealing devices 22 are fixed to the central side surface of the flange portion 21a.

[0037] Each sealing device 22 is a plate-shaped member and is fixed to the channel 2. Specifically, the sealing device 22 is fixed to the channel 2 via the seal mounting bar 21. The sealing device 22 is a long member extending in the Z-axis or Y-axis direction. The sealing device 22 is provided at a position of the gap G as viewed from the channel inlet 3.

[0038] A plurality of sealing devices 22 extending in the Y-axis direction are aligned along the Y-axis. Furthermore, a plurality of sealing devices 22 extending in the Z-axis direction are aligned along the Z-axis. The adjacent sealing devices 22 are arranged such that their ends overlap each other in the longitudinal direction.

[0039] As in Fig. 3, the seal device 22 integrally includes a fixing portion 22a in surface contact with the seal mounting strip 21 via a gasket 26, a curved portion 22b curved substantially perpendicularly from the downstream end to the central side of the fixing portion 22a, and an abutment portion 22c extending from the central end to the central side of the curved portion 22b. The seal device 22 presses itself against the seal plate 23. That is, the seal device 22 presses the seal plate 23 downstream by elastic force. Furthermore, the seal device 22 is not fixed to the seal plate 23 and the first plate-type catalyst 24. That is, the sealing device 22 is arranged so that it is movable relative to the sealing plate 23 and the first plate-type catalyst 24.

[0040] As in Fig. 2 and Fig. 3, the fixing part 22a is provided at the outer end of the sealing device 22. The fixing part 22a is pressed from the central side by a metal press fitting 27. The fixing part 22a is fixed to the flange part 21a of the seal mounting strip 21 by a plurality of fastening means 28. Specifically, the fixing part 22a is fixed to the flange part 21a by the fastening means 28, which penetrate the metal press fitting 27, the fixing part 22a, and the seal 26. It should be noted that in Fig. 2 the representation of the fastening means 28 is omitted for illustration purposes.

[0041] The contact part 22c is provided at the central end of the sealing device 22. The contact part 22c is arranged between the sealing plate 23 and the first plate-type catalyst 24. Specifically, the upstream surface of the contact part 22c is in surface contact with the downstream surface of the first plate-type catalyst 24. Furthermore, the upstream surface of the contact part 22c is in surface contact with the upstream surface of the sealing plate 23.

[0042] As in Fig. 2 and Fig. As shown in Figure 3, the sealing plate 23 is a plate-shaped member. The central end of the sealing plate 23 is fixed to the upstream side of the flange portion 13a of the wall 13, the upstream side of the second support beam 12b, and the like. The sealing plate 23 protrudes outward from the upstream surface of the flange portion 13a of the wall 13, the upstream surface of the second support beam 12b, and the like. The sealing plate 23 is arranged downstream of the sealing device 22. The sealing plate 23 is provided over substantially the entire circumferential area of ​​the exhaust gas denitrifier 6. The outer end of the sealing plate 23 is located outside the fixed part 22a of the sealing device 22 in the gap G, as seen from the channel inlet 3. At the outer end of the sealing plate 23 is the bent and downstream extending flange part 23a.The outer peripheral surface of the flange part 23a faces the inner peripheral surface of the thermal insulation material 7.

[0043] The first plate-type catalyst 24 is a flat, plate-shaped member. The first plate-type catalyst 24 is fixed to the exhaust denitrifier 6. Specifically, the first plate-type catalyst 24 is fixed to the exhaust denitrifier 6 via the sealing plate 23. The first plate-type catalyst 24 is a long member extending in the Z-axis or Y-axis direction. The outer end of the first plate-type catalyst 24 is located at a position of the gap G, as viewed from the passage inlet 3.

[0044] The majority of the first plate-type catalysts 24 extending in the Y-axis direction are aligned along the Y-axis. Furthermore, the majority of the first plate-type catalysts 24 extending in the Z-axis direction are aligned in the Z-axis direction.

[0045] The central end of the first plate-type catalyst 24 is fixed to the sealing plate 23. The outer end of the first plate-type catalyst 24 abuts the contact part 22c of the sealing device 22. The first plate-type catalyst 24 is arranged to face the sealing plate 23. The first plate-type catalyst 24 sandwiches the contact part 22c of the sealing device 22 between the sealing plate 23 and the first plate-type catalyst 24.

[0046] As in Fig. 2 and Fig. 3, the central end of the first plate-type catalyst 24 is pressed from the upstream side by a metal press fitting 31. The central end of the first plate-type catalyst 24 is fixed to the upstream side surface of the sealing plate 23 with a plurality of fasteners 32. Specifically, the central end of the first plate-type catalyst 24 is fixed to the sealing plate 23 by the fasteners 32 that pass through the metal press fitting 31 and the first plate-type catalyst 24. The outer end of the first plate-type catalyst 24 is not fixed to any member. The clamping of the fasteners 32 causes the free end (outer end) of the first plate-type catalyst 24 to press the sealing device 22 against the sealing plate 23 by elastic force. Fig. 2, the illustration of the fastening means 32 is omitted for the sake of clarity.

[0047] The first plate-type catalyst 24 is provided upstream of the sealing device 22 and the sealing plate 23. The first plate-type catalyst 24 covers the space between the sealing device 22 and the sealing plate 23 from the upstream.

[0048] The first plate-type catalyst 24 is formed by a denitrification catalyst. Specifically, the first plate-type catalyst 24 is a plate-shaped metal element (e.g., made of stainless steel) that supports components of the denitrification catalyst. The first plate-type catalyst 24 is elastically deformable like a leaf spring. The component of the denitrification catalyst is based, for example, on titanium oxide.

[0049] In addition, the components of the denitrification catalyst are exposed on the surface of the first plate-type catalyst 24. In this way, the first plate-type catalyst 24 can denitrify an exhaust gas that comes into contact with it.

[0050] According to the present embodiment, the following effects and advantages are achieved.

[0051] Since high-temperature exhaust gas flows through the duct 2, the duct 2 and the exhaust denitrifier 6 are thermally expanded by the heat of the exhaust gas. Since the thermal insulation material 7 is attached to the inner wall of the duct 2 in the present embodiment, a temperature difference and a thermal expansion difference may occur between the duct 2 and the exhaust denitrifier 6.

[0052] In the present embodiment, the sealing member (sealing mounting bar 21 and sealing device 22) and the member (sealing plate 23 and first plate-type catalyst 24) fixed to the exhaust gas denitrifier 6 are not fixed to each other. That is, the member fixed to the exhaust gas denitrifier 6 and the member fixed to the exhaust gas denitrifier 6 seal the gap G while being movable relative to each other. Thus, even when there is a thermal expansion difference between the exhaust gas denitrifier 6 and the passage 2, the sealing member (sealing mounting bar 21 and sealing device 22) fixed to the passage 2 and the sealing member (sealing plate 23 and first plate-type catalyst 24) fixed to the passage 2 can move (slide and move) relative to each other, thereby absorbing the thermal expansion difference between the passage 2 and the exhaust gas denitrifier 6.

[0053] Furthermore, in the present embodiment, the first plate-type catalyst 24 is disposed in the gap G formed between the passage 2 and the exhaust denitrifier 6. Thus, the exhaust gas that takes a short path (that is, the exhaust gas flows downstream of the exhaust denitrifier 6 without passing through the exhaust denitrifier 6) via the gap G formed between the passage 2 and the exhaust denitrifier 6 is denitrated by contact with the first plate-type catalyst 24. Since the exhaust gas that takes a short path via the gap G formed between the passage 2 and the exhaust denitrifier 6 can be denitrated, the amount of non-denitrified exhaust gas flowing downstream of the exhaust denitrifier 6 can be reduced.

[0054] Particularly, in the present embodiment, since the first plate-type catalyst 24 covers the gap between the sealing device 22 and the sealing plate 23 from upstream, the exhaust gas taking a short path via the gap between the sealing device 22 and the sealing plate 23 can be denitrified.

[0055] Furthermore, in the present embodiment, the first plate-type catalyst 24 presses the seal device 22 against the seal plate 23. Thus, the gap formed between the seal device 22 and the seal plate 23 can be kept small. Otherwise, the formation of a gap between the seal device 22 and the seal plate 23 may be difficult. Therefore, the amount of exhaust gas that takes a short path via the gap formed between the seal device 22 and the seal plate 23 can be reduced. This can reduce the amount of non-denitrified exhaust gas flowing downstream of the exhaust denitrifier 6.

[0056] In the present embodiment, the first plate-type catalyst 24 is a plate-shaped metal member. Accordingly, the first plate-type catalyst 24 is elastically deformed with a relatively large stress. Therefore, the first plate-type catalyst 24 can strongly press the seal device 22 against the seal plate 23. Since the gap formed between the seal device 22 and the seal plate 23 can be reduced, the amount of exhaust gas that takes a short path can be further reduced. [Modified Example 1]

[0057] Next, a modified example of the present embodiment will be described with reference to Fig. 4. The present modified example differs from the above first embodiment in that a second plate-type catalyst 25 is provided between the sealing device 22 and the sealing plate 23. Since the present modified example is substantially identical to the above first embodiment, the same features are identified by the same references, and the detailed description is omitted.

[0058] As in Fig. 4, a sealing structure 20A according to the present modified example is provided with the second plate-type catalyst (second catalyst sealing part) 25 between the sealing device 22 and the sealing plate 23.

[0059] The second plate-type catalyst 25 is a flat, plate-shaped member. The second plate-type catalyst 25 is fixed to the exhaust gas denitrifier 6. Specifically, the second plate-type catalyst 25 is fixed to the exhaust gas denitrifier 6 via the sealing plate 23. The second plate-type catalyst 25 is a long member extending in the Z-axis direction or the Y-axis direction. The outer end of the second plate-type catalyst 25 is located at a position of the gap G, as viewed from the passage inlet 3.

[0060] The majority of second plate-type catalysts 25 extending in the Y-axis direction are aligned along the Y-axis. Furthermore, the majority of second plate-type catalysts 25 extending in the Z-axis direction are aligned along the Z-axis.

[0061] The second plate-type catalyst 25 is formed from a denitrification catalyst in the same manner as the first plate-type catalyst 24. Since the structure of the second plate-type catalyst 25 is the same as that of the first plate-type catalyst 24, a detailed description is omitted.

[0062] The central end of the second plate-type catalyst 25 is fixed to the sealing plate 23. The outer end of the second plate-type catalyst 25 abuts the contact part 22c of the sealing device 22. The upstream surface of the second plate-type catalyst 25 abuts the contact part 22c of the sealing device 22. The upstream surface of the second plate-type catalyst 25 is arranged to face the first plate-type catalyst 24. The second plate-type catalyst 25, with the contact part 22c of the sealing device 22, is located between the first plate-type catalyst 24 and the second plate-type catalyst 25. The downstream surface of the second plate-type catalyst 25 is in surface contact with the upstream surface of the sealing plate 23.

[0063] The central end of the second plate-type catalyst 25 is fixed to the upstream side surface of the sealing plate 23 with a plurality of fasteners 32. Specifically, the central end of the second plate-type catalyst 25 is fixed to the sealing plate 23 by the fasteners 32 passing through the metal press fitting 31, the first plate-type catalyst 24, and the second plate-type catalyst 25. The outer ends of the first plate-type catalyst 24 and the second plate-type catalyst 25 are not fixed to any one member.

[0064] According to the present modified example, the following effects and advantages are achieved.

[0065] In the present modified example, the second plate-type catalyst 25 is disposed between the seal device 22 and the seal plate 23. Further, the second plate-type catalyst 25 is formed of a denitrification catalyst. Accordingly, the exhaust gas comes into contact with the second plate-type catalyst 25 via a short path through the gap formed between the seal device 22 and the seal plate 23, and is thereby denitrified. Since the exhaust gas, which takes a short path through the gap formed between the seal device 22 and the seal plate 23, can be denitrified, the amount of non-denitrified exhaust gas flowing downstream of the exhaust denitrifier 6 can be reduced.

[0066] Since the second plate-type catalyst 25 is provided between the sealing device 22 and the sealing plate 23, the pressure loss of an exhaust gas that takes a short path across the gap formed between the sealing device 22 and the sealing plate 23 can be increased. This makes it difficult for the exhaust gas to pass through the gap. Since the amount of exhaust gas that takes a short path across the gap can be further reduced, the amount of non-denitrified exhaust gas flowing downstream of the exhaust denitrifier 6 can be further reduced. [Modified Example 2]

[0067] Next, a modified example of the present embodiment will be described with reference to Fig. 5. The present modified example differs from the above first embodiment in that the first plate-type catalyst 24 is inclined with respect to the sealing plate 23. Since the present modified example is substantially identical to the above first embodiment, the same features are identified by the same references, and the detailed description is omitted.

[0068] As in Fig. 5, in a sealing structure 20B according to the present modified example, the first plate-type catalyst 24 is arranged to be inclined with respect to the sealing plate 23. Specifically, the first plate-type catalyst 24 is inclined so that the distance from the sealing device 22 increases toward the outer end (abutment part 22c) that abuts the sealing device 22. In other words, the first plate-type catalyst 24 is inclined so that the outer end (unfixed end) is closer to the sealing plate 23 than the central end (fixed end).

[0069] The sealing plate 23 is provided with an engagement part 35 into which the fastening means 32 engages on the upper side.

[0070] According to this modified example, the following effects and advantages are achieved.

[0071] In the present modified example, by tightening the fastener 32, it is possible to press the sealing device 22 more strongly against the sealing plate 23 by the elastic force of the first plate-type catalyst 24. This can reduce the gap formed between the sealing device 22 and the sealing plate 23. Otherwise, the formation of a gap between the sealing device 22 and the sealing plate 23 may be difficult. This can further reduce the amount of exhaust gas that takes a short path. (Second embodiment)

[0072] Next, a second embodiment of the present disclosure will be described with reference to Fig. 6. The present embodiment differs from the above first embodiment in that a first catalyst part (third catalyst sealing part) 40 is provided in an overlapping portion of the sealing devices 22 adjacent to each other. Since the present embodiment is substantially the same as the above first embodiment, the same features are identified by the same references, and the detailed description is omitted. Note that in Fig. 6, the illustration of the first plate-type catalysts 24 has been omitted for the purpose of illustration. Furthermore, the one-point chain line in Fig. 6 is an exploded view of the sealing structure 20C.

[0073] As in Fig. As shown in Fig. 6, in the sealing structure 20C according to the present embodiment, each first catalyst part 40 formed of a denitrification catalyst is provided between the overlapping ends of the sealing devices 22. The first catalyst part 40 is arranged such that one end in the Y-axis direction is in contact with the top surface of the sealing device 22 and the other end in the Y-axis direction is in contact with the bottom surface of the sealing device 22.

[0074] The first catalyst part 40 is a flexible plate-shaped member and has a shape corresponding to the sealing device 22, in particular a shape corresponding to the curved part 22b of the sealing device 22.

[0075] The first catalyst part 40 is formed from a denitrification catalyst. Specifically, the first catalyst part 40 is a fabric formed from heat-resistant fibers that supports components of the denitrification catalyst. The heat-resistant fiber can be, for example, a ceramic fiber or a glass fiber.

[0076] The present embodiment achieves the following effects and advantages.

[0077] Since the sealing device 22 can be deformed by heat, a gap can be formed between the overlapping ends of the sealing devices 22.

[0078] In the present embodiment, the first catalyst part 40 is provided between the overlapping ends of the sealing devices 22. Thus, the exhaust gas that takes a short path through the gap between the overlapping ends of the sealing devices 22 is denitrated by contact with the first part of the catalyst 40. Since the exhaust gas that takes a short path through a gap formed between the ends of the overlapping sealing devices 22 can be denitrated, the amount of non-denitrated exhaust gas flowing downstream of the exhaust denitrifier 6 can be reduced.

[0079] Furthermore, since the first catalyst part 40 is provided between the overlapping ends of the sealing devices 22, the first catalyst part 40 can increase the pressure loss of an exhaust gas that takes a short path across the gap formed between the overlapping ends of the sealing devices 22. This makes it difficult for the exhaust gas to pass through the gap. Since the amount of exhaust gas that takes a short path across the gap can be further reduced, the amount of non-denitrified exhaust gas flowing downstream of the exhaust denitrifier 6 can be further reduced.

[0080] In the present embodiment, the first catalyst member 40 is a fabric formed from heat-resistant fibers that supports components of the denitrification catalyst. Accordingly, the first catalyst member 40 is flexible compared to a case where the catalyst member is formed from a metallic material, for example. Therefore, the first catalyst member 40 is deformed into a shape corresponding to a gap formed between the ends of the overlapping sealing devices 22 and can thus further fill the gap. This makes it more difficult for the exhaust gas to pass through the gap. Since the amount of exhaust gas that takes a short path via the gap can be further reduced, the amount of non-denitrified exhaust gas flowing downstream of the exhaust denitrifier 6 can be further reduced. [Third Embodiment]

[0081] Next, a third embodiment of the present disclosure will be described with reference to Fig. 7. The present embodiment differs from the above second embodiment in that second catalyst parts (fourth catalyst sealing parts) 45 are provided. Since the present modified example is substantially identical to the above second embodiment, the same features are identified by the same references, and the detailed description is omitted. Note that in Fig. 7 the illustration of the first plate-type catalyst 24 has been omitted for the purpose of illustration.

[0082] As in Fig.As shown in FIG. 7, a sealing structure 20D according to the present embodiment includes the second catalyst parts 45, each covering a gap formed between one end of a first sealing member 22A extending in the Z-axis direction and one end of the second sealing member 22B extending in the Y-axis direction. Each second catalyst part 45 has a first part covering the upstream side of the first sealing member 22A and a second part covering the upstream side of the second sealing member 22B. The second catalyst part 45 is formed into a substantially L-shape.

[0083] The second catalyst part 45 is formed from a denitrification catalyst. Specifically, the second catalyst part 45 is a fabric formed from heat-resistant fibers that is completely coated with components of the denitrification catalyst. An example of a heat-resistant fiber can be a ceramic fiber or a glass fiber.

[0084] According to the present embodiment, the following effects and advantages are achieved.

[0085] In the present embodiment, the second catalyst part 45 covers a gap formed between one end of the first sealing device 22A and one end of the second sealing device 22B. In this way, the exhaust gas that takes a short path across the gap formed between one end of the first sealing device 22A and one end of the second sealing device 22B is denitrated by contact with the second catalyst part 45. Since the exhaust gas that takes a short path across the gap formed between one end of the first sealing device 22A and one end of the second sealing device 22B can be denitrated, the amount of non-denitrated exhaust gas flowing downstream of the exhaust denitrifier 6 can be reduced.

[0086] Since the second catalyst part 45 covers a gap formed between one end of the first sealing device 22A and one end of the second sealing device 22B, this makes it difficult for the exhaust gas to pass through the gap formed between one end of the first sealing device 22A and one end of the second sealing device 22B. Since the amount of exhaust gas passing through the gap can be further reduced, the amount of non-denitrified exhaust gas flowing downstream of the exhaust denitrifier 6 can be further reduced.

[0087] In the present embodiment, the second catalyst member 45 is a fabric formed from heat-resistant fibers and completely coated with components of the denitrification catalyst. Accordingly, the second catalyst member 45 is more flexible compared to a case where the catalyst member is formed from, for example, a metallic material. Since the second catalyst member 45 can be easily deformed into a shape conforming to the first sealing means 22A and the second sealing means 22B, the gap formed between one end of the first sealing means 22A and one end of the second sealing means 22B can be more appropriately covered. Since the amount of exhaust gas taking a short path via the gap can be further reduced, the amount of non-denitrified exhaust gas flowing downstream of the exhaust denitrifier 6 can be further reduced.

[0088] It should be noted that the present disclosure is not limited to the embodiment described above, and modifications may be made within the scope of application without departing from the spirit of the disclosure.

[0089] For example, Modified Example 1 and Modified Example 2 for the above-described first embodiment may be combined with each other. Furthermore, Modified Example 1 and / or Modified Example 2 for the above-described first embodiment may be combined with the second embodiment and / or the third embodiment.

[0090] Furthermore, gases to be subjected to denitrification treatment are not limited to the exhaust gas discharged from a gas turbine and are applicable to gases discharged from boilers, engines, combustion furnaces, incinerators and various reaction furnaces.

[0091] Although the example in which an exhaust gas denitrifier is provided in the duct 2 provided with the thermal insulation materials 7 on the inner peripheral surface (hereinafter referred to as "inner thermal insulation duct") has been described in the above embodiments, the present disclosure is not limited thereto. For example, an exhaust gas denitrifier may be provided within a duct provided with thermal insulation material on the outer peripheral surface (hereinafter referred to as "outer thermal insulation duct").However, as described above, the sealing structures described in the above embodiments can sufficiently absorb a thermal expansion difference between the sealing member (the seal mounting bar 21 and the sealing device 22) fixed to the duct 2 and the sealing member (the sealing plate 23 and the first plate-type catalyst 24) fixed to the exhaust gas denitrifier 6, and are therefore more effective when attached to the inner heat insulation duct with a large thermal expansion difference between the duct and the exhaust gas denitrifier than when attached to the outer heat insulation duct.

[0092] Although the example in which the exhaust gas denitrifier and the sealing structure are provided within a horizontal duct in which exhaust gas flows in a horizontal direction was described in the above embodiment, the present disclosure is not limited thereto. For example, the exhaust gas denitrifier and the sealing structure may be provided in a vertical-type duct in which exhaust gas flows in a vertical direction. However, as described above, in the sealing structures described in the above embodiments, the member fixed to the duct 2 (the seal mounting bar 21 and the seal device 22) and the member fixed to the exhaust gas denitrifier 6 (the seal plate 23 and the first plate-type catalyst 24) are not fixed to each other and are movable relative to each other.The sealing structures described in the above embodiments are therefore less susceptible to damage even in the case of a displacement difference across the entire circumference of the channel 2. Thus, the sealing structures described in the above embodiments are also effective in a horizontal channel, where a displacement difference across the entire circumference of the channel 2 is more likely than in a vertical channel.

[0093] The sealing structure, the heat recovery steam generator and the exhaust gas sealing method according to the embodiments described above are understood to mean, for example, the following.

[0094] The sealing structure according to one aspect of the present disclosure is a sealing structure (20) configured to seal a gap formed between a duct (2) in which an exhaust gas flows and an exhaust gas denitrifier (6) arranged in the duct (2), the sealing structure comprising: at least one duct-side sealing part (22) fixed to the duct (2) and arranged in the gap; an exhaust gas denitrifier-side sealing part (23) fixed to the exhaust gas denitrifier (6) and arranged in the intermediate space, which rests against or is close to the channel-side sealing part (22), and a first catalyst sealing part (24) fixed to the exhaust gas denitrifier (6), arranged in the intermediate space and configured to press the channel-side sealing part (22) against the exhaust gas denitrifier-side sealing part (23), and the first catalyst sealing part (24) is formed from a denitrification catalyst.

[0095] Since high-temperature exhaust gas flows through the duct, the heat from the exhaust gas causes the duct and the exhaust denitrifier to thermally expand. If, for example, thermal insulation material is attached to the inner wall of the duct or similar, a thermal expansion difference may occur between the duct and the exhaust denitrifier at this time.

[0096] In the above configuration, the duct-side sealing part fixed to the duct side and the sealing part (the exhaust denitrifier-side sealing part and the first catalyst sealing part) fixed to the exhaust denitrifier side are not fixed to each other. That is, the duct-side sealing part and the exhaust denitrifier-side sealing part seal the gap while being movable relative to each other. Thus, even when a thermal expansion difference occurs between the duct and the exhaust denitrifier, the duct-side sealing part and the exhaust denitrifier-side sealing part can move (slide and move) relative to each other, and this can absorb the thermal expansion difference.

[0097] Furthermore, in the above configuration, the first catalyst sealing member is disposed in the gap formed between the passage and the exhaust denitrifier. Thus, the exhaust gas that takes a short path (i.e., the exhaust gas flows downstream of the exhaust denitrifier without passing through the exhaust denitrifier) ​​via the gap formed between the passage and the exhaust denitrifier is denitrified by contact with the first catalyst sealing member. Since the exhaust gas that takes a short path via the gap formed between the passage and the exhaust denitrifier can be denitrified, the amount of non-denitrified exhaust gas flowing downstream of the exhaust denitrifier can be reduced.

[0098] Furthermore, with the above configuration, the first catalyst seal member presses the passage-side seal member against the exhaust denitrifier-side seal member. Thus, the gap formed between the passage-side seal member and the exhaust denitrifier-side seal member can be kept small. Otherwise, the formation of a gap between the passage-side seal member and the exhaust denitrifier-side seal member may be difficult. Therefore, the amount of exhaust gas that takes a short path via the gap formed between the passage-side seal member and the exhaust denitrifier-side seal member can be reduced. Thus, the amount of non-denitrified exhaust gas flowing downstream of the exhaust denitrifier can be reduced.

[0099] Further, in the sealing structure according to one aspect of the present disclosure, the first catalyst sealing part (24) is a plate-shaped metal member supporting a denitrification catalyst component.

[0100] In the above configuration, the first catalyst sealing part is a plate-shaped metal element. Accordingly, the first catalyst sealing part is elastically deformed with relatively large stress. Therefore, the first catalyst sealing part can strongly press the passage-side sealing part against the exhaust gas denitrifier-side sealing part. Since the gap formed between the passage-side sealing part and the exhaust gas denitrifier-side sealing part can be made smaller, the amount of exhaust gas that takes a short path can be further reduced.

[0101] An example of a metal used for the first catalyst sealing part is stainless steel.

[0102] Furthermore, the sealing structure according to one aspect of the present disclosure comprises a second catalyst sealing part (25) fixed to the exhaust gas denitrifier (6) and arranged between the passage-side sealing part (22) and the exhaust gas denitrifier-side sealing part (23), and the second catalyst sealing part (25) is formed of a denitrification catalyst.

[0103] In the above configuration, the second catalyst sealing part is disposed between the passage-side sealing part and the exhaust denitrifier-side sealing part. Furthermore, the second catalyst sealing part is formed of a denitrification catalyst. Accordingly, the exhaust gas, which takes a short path via the gap formed between the passage-side sealing part and the exhaust denitrifier-side sealing part, comes into contact with the second catalyst sealing part and is thereby denitrated. Since the exhaust gas, which takes a short path via the gap formed between the passage-side sealing part and the exhaust denitrifier-side sealing part, can be denitrified, the amount of non-denitrified exhaust gas flowing downstream of the exhaust denitrifier can be reduced.

[0104] Since the second catalyst seal part is provided between the passage-side seal part and the exhaust denitrifier-side seal part, the pressure loss of an exhaust gas that takes a short path across the gap formed between the passage-side seal part and the exhaust denitrifier-side seal part can be increased. This makes it difficult for the exhaust gas to pass through the gap. Since the amount of exhaust gas that takes a short path across the gap can be further reduced, the amount of non-denitrified exhaust gas flowing downstream of the exhaust denitrifier can be further reduced.

[0105] Furthermore, in the sealing structure according to one aspect of the present disclosure, the first catalyst sealing part (24) is inclined with respect to the exhaust gas nitrogen side sealing part (23) such that the distance to the channel-side sealing part (22) increases with increasing distance to an abutting part abutting the channel-side sealing part (22).

[0106] In the above configuration, the first catalyst seal member is inclined such that the distance to the passage-side seal member increases with the distance to the contact part abutting the passage-side seal member. This allows the first catalyst seal member to press the passage-side seal member more strongly against the exhaust-gas-seal-side seal member. Since the gap formed between the passage-side seal member and the exhaust-gas-seal-side seal member can be reduced, the amount of exhaust gas that takes a short path can be further reduced.

[0107] Further, in the sealing structure according to one aspect of the present disclosure, a plurality of channel-side sealing parts (22) are provided, wherein the plurality of channel-side sealing parts (22) are aligned along a crossing direction which is a direction intersecting an exhaust gas flow, wherein the adjacent channel-side sealing parts (22) are arranged such that the ends of the channel-side sealing parts overlap each other, and wherein a third catalyst sealing part (40) formed of a denitrification catalyst is provided between the overlapping ends.

[0108] In the above configuration, the third catalyst seal member is provided between the ends of the overlapping passage-side seal members. Thus, the exhaust gas that takes a short path across the gap formed between the ends of the overlapping passage-side seal members is denitrified by contact with the third catalyst seal member. Since the exhaust gas that takes a short path across the gap formed between the ends of the overlapping passage-side seal members can be denitrified, the amount of non-denitrified exhaust gas flowing downstream of the exhaust denitrifier can be reduced.

[0109] Since the third catalyst seal member is provided between the ends of the overlapping passage-side seal members, the third catalyst seal member can increase the pressure loss of the exhaust gas that takes a short path across the gap formed between the ends of the overlapping passage-side seal members. This makes it difficult for the exhaust gas to pass through the gap. Since the amount of exhaust gas that takes a short path across the gap can be further reduced, the amount of non-denitrified exhaust gas flowing downstream of the exhaust denitrifier can be further reduced.

[0110] Further, in the sealing structure according to one aspect of the present disclosure, the third catalyst sealing member (40) is a fabric formed of heat-resistant fibers carrying a denitrification catalyst component.

[0111] In the above configuration, the third catalyst sealing member is a fabric formed from heat-resistant fibers containing a denitrification catalyst. Accordingly, the third catalyst sealing member is more flexible compared to a case where the catalyst sealing member is formed from, for example, a metallic material. Therefore, the third catalyst sealing member is deformed into a shape corresponding to a gap formed between the ends of the passage-side sealing members that overlap each other, and can thus further fill the gap. This makes it difficult for the exhaust gas to pass through the gap. Since the amount of exhaust gas that takes a short path via the gap can be further reduced, the amount of non-denitrified exhaust gas flowing downstream of the exhaust gas denitrification catalyst can be further reduced.

[0112] Furthermore, in the sealing structure according to one aspect of the present disclosure, a plurality of channel-side sealing parts (22) are provided, the plurality of channel-side sealing parts (22) having a first channel-side sealing part (22A) extending in a first intersecting direction (the Z-axis direction), which is one of the directions intersecting an exhaust gas flow, and a second channel-side sealing part (22B) extending in a second intersecting direction, which is one of the directions intersecting the exhaust gas flow and is a direction intersecting the first intersecting direction (the Z-axis direction), the sealing structure further comprising a fourth catalyst sealing part (45) covering a gap formed between one end of the first channel-side sealing part (22A) and one end of the second channel-side sealing part (22B),and the fourth catalyst sealing part (45) is formed from a denitrification catalyst.,

[0113] In the above configuration, the fourth catalyst sealing part covers a gap formed between one end of the first passage-side sealing part and one end of the second passage-side sealing part. In this way, the exhaust gas that takes a short path across the gap formed between one end of the first passage-side sealing part and one end of the second passage-side sealing part is denitrified by contact with the fourth catalyst sealing part. In this way, since the exhaust gas that takes a short path across the gap formed between one end of the first passage-side sealing part and one end of the second passage-side sealing part can be denitrified, the amount of non-denitrified exhaust gas flowing downstream of the exhaust denitrifier can be reduced.

[0114] Since the fourth catalyst seal member covers a gap formed between one end of the first passage-side seal member and one end of the second passage-side seal member, it is difficult for the exhaust gas to flow through the gap formed between one end of the first passage-side seal member and one end of the second passage-side seal member. Since the amount of exhaust gas that takes a short path across the gap can be further reduced, the amount of non-denitrified exhaust gas flowing downstream of the exhaust denitrifier can be further reduced.

[0115] Further, in the sealing structure according to one aspect of the present disclosure, the fourth catalyst sealing member (45) is a fabric formed of heat-resistant fibers carrying a denitrification catalyst component.

[0116] In the above configuration, the fourth catalyst sealing member is a fabric formed from heat-resistant fibers supporting a denitrification catalyst component. Accordingly, the fourth catalyst sealing member is more flexible compared to a case where the catalyst sealing member is formed from, for example, a metallic material. Since the fourth catalyst sealing member can be easily deformed into a shape corresponding to the first passage-side sealing member and the second passage-side sealing member, the gap formed between one end of the first passage-side sealing member and one end of the second passage-side sealing member can be more appropriately covered. Since the amount of exhaust gas taking a short path via the gap can be further reduced, the amount of non-denitrified exhaust gas flowing downstream of the exhaust denitrifier can be further reduced.

[0117] The heat recovery steam generator according to one aspect of the present disclosure comprises: a duct (2) through which an exhaust gas flows; a heat exchanger unit arranged in the duct (2) and configured to recover heat of an exhaust gas; an exhaust gas denitrifier (6) arranged in the duct (2); and the sealing structure (20) according to any one of the above points, which is configured to seal a gap formed between the duct (2) and the exhaust gas denitrifier (6).

[0118] The exhaust gas sealing method according to one aspect of the present disclosure is an exhaust gas sealing method using a sealing structure (20) configured to seal a gap formed between a duct (2) through which an exhaust gas flows and an exhaust gas denitrifier (6) arranged in the duct (2), wherein the sealing structure (20) comprises a duct-side sealing part (22) fixed to the duct (2) and arranged in the gap, an exhaust gas denitrifier-side sealing part (23) fixed to the exhaust gas denitrifier (6), a first catalyst sealing part (24) fixed to the exhaust gas denitrifier (6), arranged in the gap and abutting or close to the duct-side sealing part (22), the first catalyst sealing part (24) fixed to the exhaust gas denitrifier (6), arranged in the gap and configured to seal the duct-side sealing part (22) against the exhaust gas denitrifier-side Sealing part (23) to press,wherein the first catalyst sealing part (24) is formed from a denitrification catalyst, and the exhaust gas sealing method comprises: sealing a gap formed between the channel (2) and the exhaust gas denitrifier (6) using the channel-side sealing part (22), the exhaust gas denitrifier-side sealing part (23) and the first catalyst sealing part (24). [List of reference symbols] 1 heat recovery steam generator 2 channel 3 channel entry 4 channel output 5 Heat exchanger unit 6 exhaust gas denitrifiers 7 Thermal insulation material 9 drum 11 Catalyst package 12 supporting frames 12a first supporting beam 12b second supporting beam 13 Wall 13a Flange part 20 Sealing structure 20A sealing structure 20B Sealing structure 20C sealing structure 20D sealing structure 21 Sealing mounting strip 21a Flange part 22 Sealing device 22A first sealing device 22B second sealing device 22a Fixing part 22b curved part 22c system part 23 Sealing plate 23a Flange part 24 first plate-type catalyst 25 second plate-type catalyst 26 Seal 27 metallic press fitting 28 fasteners 31 metallic press fitting 32 fasteners 35 engaging part 40 first catalyst part 45 second catalyst part G space QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2014-178103

[0005]

Claims

[1] A sealing structure configured to seal a gap formed between a channel through which an exhaust gas flows and an exhaust gas denitrifier disposed in the channel, the sealing structure comprising: at least one channel-side sealing part which is fixed to the channel and arranged in the intermediate space; an exhaust gas denitrifier-side sealing part which is fixed to the exhaust gas denitrifier, is arranged in the intermediate space and is adjacent to or close to the duct-side sealing part; and a first catalyst sealing part which is attached to the exhaust gas denitrifier, is arranged in the gap and is configured to press the channel-side sealing part against the exhaust gas denitrifier-side sealing part, wherein the first catalyst sealing part is formed from a denitrification catalyst. [2] The sealing structure according to claim 1, wherein the first catalyst sealing part is a plate-shaped metal member carrying a denitrification catalyst component. [3] The sealing structure according to claim 1 or 2, further comprising a second catalyst sealing part fixed to the exhaust gas denitrifier and arranged between the passage-side sealing part and the exhaust gas denitrifier-side sealing part, the second catalyst sealing part being formed of a denitrification catalyst. [4] Sealing structure according to one of claims 1 to 3, wherein the first catalyst sealing part is inclined with respect to the exhaust gas denitrifier-side sealing part such that the distance to the channel-side sealing part increases with increasing distance to an abutting part abutting the channel-side sealing part. [5] Sealing structure according to one of claims 1 to 4, wherein a plurality of channel-side sealing parts are provided, wherein the plurality of channel-side sealing parts are aligned along a crossing direction, which is a direction crossing an exhaust gas flow, wherein the adjacent channel-side sealing parts are arranged such that the ends of the channel-side sealing parts overlap each other, and wherein a third catalyst sealing member formed of a denitrification catalyst is provided between the overlapping ends. [6] The sealing structure according to claim 5, wherein the third catalyst sealing member is a fabric formed of heat-resistant fibers carrying a denitrification catalyst component. [7] Sealing structure according to one of claims 1 to 6, wherein a plurality of channel-side sealing parts are provided, wherein the plurality of channel-side sealing parts comprises a first channel-side sealing part extending in a first intersecting direction, which is one of the directions intersecting with an exhaust gas flow, and a second channel-side sealing part extending in a second intersecting direction, which is one of the directions intersecting with the exhaust gas flow and is a direction intersecting the first intersecting direction, wherein the sealing structure further comprises: a fourth catalyst sealing part covering a gap formed between one end of the first channel-side sealing part and one end of the second channel-side sealing part, wherein the fourth catalyst sealing part is formed from a denitrification catalyst. [8] The sealing structure according to claim 7, wherein the fourth catalyst sealing member is a fabric formed of heat-resistant fibers carrying a denitrification catalyst component. [9] Heat recovery steam generator, comprising: a channel through which an exhaust gas flows; a heat exchanger unit disposed in the duct and configured to recover heat from an exhaust gas; an exhaust gas denitrifier arranged in the duct; and the sealing structure according to any one of claims 1 to 8, configured to seal a gap formed between the duct and the exhaust denitrifier. [10] An exhaust gas sealing method using a sealing structure configured to seal a gap formed between a passage through which an exhaust gas flows and an exhaust gas denitrifier arranged in the passage, wherein the sealing structure comprises a channel-side sealing part which is fixed to the channel and arranged in the intermediate space, an exhaust gas denitrifier-side sealing part which is attached to the exhaust gas denitrifier, is arranged in the intermediate space and is in contact with or close to the duct-side sealing part, and a first catalyst sealing part fixed to the exhaust gas denitrifier, arranged in the gap, and configured to press the channel-side sealing part against the exhaust gas denitrifier-side sealing part, wherein the first catalyst sealing part is formed from a denitrification catalyst, The exhaust sealing process includes: Sealing a gap formed between the duct and the exhaust denitrifier using the duct-side sealing part, the exhaust denitrifier-side sealing part and the first catalyst sealing part.

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