JP7391651B2 - Denitrification equipment, boiler system, and installation method of denitrification equipment - Google Patents

Description

The present disclosure relates to a denitrification device, a boiler system, and a method for installing the denitrification device.

A large boiler such as a coal-fired boiler has a hollow furnace installed vertically, and a plurality of combustion burners are arranged along the circumferential direction of the furnace wall. In addition, in a coal-fired boiler, a flue is connected vertically above the furnace, and a heat exchanger for generating steam is arranged in this flue. Then, the combustion burner injects a mixture of fuel and air (oxidizing gas) into the furnace to form a flame, and combustion gas is generated and flows into the flue. A heat exchanger is installed in a region where combustion gas flows, and superheated steam is generated by heating water or steam flowing through heat transfer tubes that make up the heat exchanger.

In such a coal-fired boiler, combustion products (coarse ash) may be generated during the progress of the oxidation reaction of the fuel. A part of the generated coarse ash is carried by the combustion gas from the furnace to the flue. In some coal-fired boilers, a screen or hopper is installed in the flue on the downstream side of the combustion gas flow from the heat exchanger to collect coarse ash. Even in such a case, it is difficult to collect all the coarse ash, and the coarse ash is transported to the denitrification equipment installed further downstream of the combustion gas flow than the screen or hopper. may be done. If the coarse ash is transported to the denitrification catalyst provided in the denitrification device, it may have an adverse effect on the denitrification catalyst, such as clogging. For this reason, for example, a denitrification device may be provided with a wire mesh (hereinafter also referred to as a "mesh") for collecting coarse ash on the upstream side of the combustion gas flow from the denitrification catalyst (for example, Patent Document 1).

Patent Document 1 discloses a denitrification device in which a collection member is laid on the top of a pillar material that forms a denitrification catalyst layer (hereinafter also referred to as "catalyst layer"), and the upstream side of the catalyst layer is covered with a repair member. Are listed. The collection member is made of a steel mesh member, has openings slightly smaller than the openings of the denitrification catalyst, and is formed to be able to collect coarse ash that is difficult to pass through the openings of the denitration catalyst.

Japanese Patent Application Publication No. 2003-164729

However, in the collection member of Patent Document 1, the collection member is formed of a one-plane net-like member. Therefore, if the collecting member becomes clogged with the collected coarse ash, it may become difficult for the combustion gas to pass through the collecting member. That is, in the area where the collection member is provided in the cross section of the flow path of the flue, the collection member may obstruct the flow of combustion gas. Therefore, for example, if a collection member is provided over the entire cross section of the flue, when a part of the collection member becomes clogged with coarse ash, the combustion gas will flow to the unclogged area. With the flow of gas, coarse ash begins to concentrate, making it even more likely to cause clogging in the cross section of the flow path, and the flow of combustion gas and coarse ash further concentrate in the less clogged area, causing much of the cross section of the flow path to become clogged. This may cause the area to become clogged more quickly. Eventually, if clogging occurs in many areas of the cross section of the flow path, the flow of combustion gas will be obstructed, making it difficult for the combustion gas to flow to the catalyst layer. Therefore, there is a possibility that denitration cannot be performed appropriately in the catalyst layer.

The present disclosure has been made in view of the above circumstances, and is intended to prevent clogging in many areas of the wire mesh section provided in the cross section of the flow path that collects combustion products contained in combustion gas. It is an object of the present invention to provide a denitrification device, a boiler system, and a method for installing the denitrification device, which can guide combustion gas to a catalyst layer and perform denitration in the catalyst layer in a suitable manner.

In order to solve the above problems, a denitrification device, a boiler system, and a method for installing a denitrification device according to the present disclosure employ the following means.
A denitrification device according to one aspect of the present disclosure is a denitrification device that is provided inside a flue through which combustion gas discharged from a furnace of a boiler flows, and denitrates the combustion gas, the denitrification device through which the combustion gas passes. and a catalyst, which is disposed upstream of the denitrification catalyst in the flow of the combustion gas so as to intersect with the flow of the combustion gas, and covers a part of the flow path cross section of the region of the flue through which the combustion gas flows. , a first wire mesh portion for collecting ash contained in the combustion gas; and a first wire mesh portion disposed upstream of the denitrification catalyst in the flow of the combustion gas so as to intersect with the flow of the combustion gas; a second wire mesh section that covers a part of the cross section of the flow path in a region where combustion gas flows and collects ash contained in the combustion gas, and the distance between the first wire mesh section and the denitrification catalyst is , the distance between the second wire mesh portion and the denitrification catalyst is different.

Further, a method for installing a denitrification device according to an aspect of the present disclosure includes a denitrification catalyst that is provided inside a flue through which combustion gas discharged from a boiler flows, and a denitrification catalyst that is provided in a flue through which the combustion gas passes; It is disposed on the upstream side of the flow of combustion gas so as to intersect with the flow of combustion gas, covers a part of the flow path cross section of the region of the flue where the combustion gas flows, and removes ash contained in the combustion gas. a first wire mesh portion for collecting; and a first wire mesh portion disposed upstream of the denitrification catalyst in the flow of the combustion gas so as to intersect with the flow of the combustion gas, and the flow in a region of the flue through which the combustion gas flows. A method for installing a denitrification device that denitrates the combustion gas, comprising: a second wire mesh section that covers a part of a road cross section and collects ash contained in the combustion gas, the first wire mesh section and the The method includes an installation step of installing the first wire mesh section and the second wire mesh section inside the flue so that the distance to the denitration catalyst and the distance between the second wire mesh section and the denitration catalyst are different.

According to the present disclosure, even if many areas of the wire mesh section provided in the cross section of the flow path that collects the combustion products contained in the combustion gas become clogged, the combustion gas can be guided to the catalyst layer. , denitrification can be suitably performed in the catalyst layer.

1 is a schematic configuration diagram showing a coal-fired boiler according to an embodiment of the present disclosure. FIG. 2 is a schematic configuration diagram showing main parts of the coal-fired boiler shown in FIG. 1. FIG. 3 is a sectional view taken along the line EE in FIG. 2. FIG. FIG. 2 is a perspective view showing a denitrification catalyst installed in the coal-fired boiler of FIG. 1. FIG. It is a perspective view which shows the 1st frame, the 1st wire mesh part, and the 3rd wire mesh part provided in the coal-fired boiler of FIG. 1. 3 is a sectional view taken along the line FF in FIG. 2. FIG. FIG. 7 is a perspective view showing a part of the collection section of FIG. 6; It is a typical side view which shows the collection part and partition plate provided in the coal-fired boiler of FIG. It is a top view which shows the collection part based on the modification of FIG. It is a perspective view which shows a part of collection part of FIG. FIG. 2 is a perspective view showing a rectifying grid provided in the coal-fired boiler of FIG. 1. FIG.

Below, preferred embodiments of a denitrification device, a boiler system, and a method of installing a denitrification device according to the present disclosure will be described with reference to the drawings. Note that the present disclosure is not limited to this embodiment, and if there are multiple embodiments, the present disclosure also includes a configuration in which each embodiment is combined.

FIG. 1 is a schematic configuration diagram showing a coal-fired boiler of this embodiment.

In the present embodiment, as a boiler in which combustion gas contains combustion products, for example, in a coal-fired boiler 10, pulverized coal obtained by pulverizing coal (carbon-containing solid fuel) is used as pulverized fuel, and this pulverized fuel is combusted by a combustion burner. This is a coal-fired (pulverized coal-fired) boiler that can generate superheated steam by exchanging the heat generated by this combustion with feed water and steam. In the following description, the term "upper" or "upper" refers to the upper side in the vertical direction, and the term "lower" or "lower" refers to the lower side in the vertical direction.

In this embodiment, as shown in FIG. 1, a coal-fired boiler 10 includes a furnace 11, a combustion device 12, and a combustion gas passage 13. The furnace 11 has a hollow rectangular tube shape and is installed along the vertical direction. The furnace wall that constitutes the furnace 11 is composed of a plurality of heat transfer tubes and fins that connect these, and exchanges the heat generated by the combustion of pulverized fuel with water and steam flowing inside the heat transfer tubes. This suppresses the rise in wall temperature.

The combustion device 12 is provided on the lower side of the furnace wall that constitutes the furnace 11 . In this embodiment, the combustion device 12 includes a plurality of combustion burners (for example, 21, 22, 23, 24, 25) mounted on the furnace wall. For example, the combustion burners 21, 22, 23, 24, and 25 are arranged at equal intervals along the circumferential direction of the furnace 11 as one set, and are arranged in multiple stages along the vertical direction. However, the shape of the furnace, the number of combustion burners in one stage, and the number of stages are not limited to this embodiment.

Each combustion burner 21, 22, 23, 24, 25 is connected to a plurality of crushers (mills) 31, 32, 33, 34, 35 via pulverized coal supply pipes 26, 27, 28, 29, 30. There is. Although not shown in the figures, each of the crushers 31, 32, 33, 34, and 35 has, for example, a rotary table supported in a housing of the crusher so as to be rotatable, and a plurality of rollers arranged above the rotary table to rotate the rotary table. They are configured to be rotatably supported in conjunction with each other. When coal is placed between multiple rollers and a rotary table, it is pulverized into a predetermined size of pulverized coal. The pulverized fuel transported to the classifier and classified within a predetermined particle size range can be supplied to the combustion burners 21, 22, 23, 24, 25 from the pulverized coal supply pipes 26, 27, 28, 29, 30. .

In addition, the furnace 11 is provided with a wind box 36 at the mounting position of each combustion burner 21, 22, 23, 24, 25, and one end of an air duct (wind path) 37 is connected to this wind box 36. There is. The air duct 37 is provided with a forced draft fan (FDF) 38 at the other end.

Further, the furnace 11 is provided with an additional air port 39 above the mounting position of each combustion burner 21, 22, 23, 24, 25. An end of a branch air duct 40 branched from the air duct 37 is connected to the additional air port 39. Therefore, the combustion air (secondary air, oxidizing gas) sent by the forced draft fan 38 is supplied from the air duct 37 to the wind box 36, and from this wind box 36 each combustion burner 21, 22, 23, 24, 25, and additional air for combustion sent by a forced draft fan 38 can be supplied from a branch air duct 40 to an additional air port 39.

The combustion gas passage 13 is connected to the upper part of the furnace 11 in the vertical direction, as shown in FIG. The combustion gas passage 13 is provided with superheaters 41, 42, 43, reheaters 44, 45, and a economizer 46 as heat exchangers for recovering the heat of the combustion gas. Heat exchange occurs between the combustion gas generated in the heat exchanger and the water and steam flowing through each heat exchanger.

As shown in FIG. 1, the combustion gas passage 13 is connected to a flue 14 on its downstream side through which the combustion gas that has undergone heat exchange is discharged. An air heater (air preheater) 49 is provided between the flue 14 and the air duct 37 to exchange heat between the air flowing through the air duct 37 and the combustion gas flowing through the flue 14. , 22, 23, 24, 25 can be heated.

Further, a denitrification device 50 is provided in the flue 14 at a position upstream of the air heater 49. The denitrification device 50 supplies a reducing agent, such as ammonia or urea water, that has the effect of reducing nitrogen oxides into the flue 14, and converts the combustion gas supplied with the reducing agent into a reaction between the nitrogen oxides and the reducing agent. The nitrogen oxides in the combustion gas are removed and reduced by the catalytic action of the denitrification catalyst 58 installed in the denitrification device 50. Note that details of the flue 14 and the denitrification device 50 will be described later.
The gas duct 48 connected to the flue 14 is provided with a dust collector 51 such as an electric dust collector, an induced draft fan (IDF) 52, a desulfurization device 53, etc. at a position downstream from the air heater 49. A chimney 54 is provided at the downstream end.

On the other hand, when the plurality of crushers 31, 32, 33, 34, 35 are driven, the generated pulverized fuel is transferred to the pulverized coal supply pipes 26, 27, 28, 29, 30 together with the conveying gas (primary air, oxidizing gas). It is supplied to combustion burners 21, 22, 23, 24, 25 through. In addition, by exchanging heat with the exhaust gas discharged from the flue 14 of the coal-fired boiler 10 by the air heater 49, the heated combustion air (secondary air, oxidizing gas) is passed from the air duct 37 through the wind box 36. and is supplied to each combustion burner 21, 22, 23, 24, 25. Then, the combustion burners 21, 22, 23, 24, and 25 blow a pulverized fuel mixture, which is a mixture of pulverized fuel and carrier gas (primary air, oxidizing gas), into the furnace 11, and also blow combustion air (secondary air) into the furnace 11. , oxidizing gas) is blown into the furnace 11, and at this time, the pulverized fuel mixture is ignited to form a flame. A flame is generated in the lower part of the furnace 11 , and high-temperature combustion gas rises within the furnace 11 and is discharged into the combustion gas passage 13 . Note that air is used as the oxidizing gas in this embodiment. It may have a higher or lower oxygen content than air, and can be used by optimizing the fuel flow rate.

In the lower region A of the furnace 11, a pulverized fuel mixture and combustion air (secondary air, oxidizing gas) are combusted to generate a flame. Here, the inside of the furnace 11 is maintained in a reducing atmosphere by setting the amount of air supplied to be less than the theoretical amount of air relative to the amount of pulverized coal supplied. That is, nitrogen oxides (NOx) generated by the combustion of pulverized coal are reduced in region B of the furnace 11, and then additional air is supplied from the additional air port 39 to complete the oxidative combustion of the pulverized coal. The amount of NOx generated by combustion of pulverized coal is reduced.

Thereafter, as shown in FIG. 1, the combustion gas is transferred to a third superheater 43, a second superheater 42, and a first superheater 41 (hereinafter sometimes simply referred to as a superheater) arranged in the combustion gas passage 13. , the second reheater 44, the first reheater 45 (hereinafter simply referred to as a reheater), and the economizer 46, and then the nitrogen oxides are reduced and removed by the denitrification device 50. After particulate matter is removed by a dust collector 51 and sulfur oxides are removed by a desulfurization device 53, they are discharged into the atmosphere from a chimney 54. Note that the heat exchangers do not necessarily have to be arranged in the order described above with respect to the combustion gas flow.

Next, details of the combustion gas passage 13, the flue 14, and the denitrification device 50 will be explained using FIGS. 2 to 8. In addition, in the following description, the upstream side and the downstream side mean the upstream side and the downstream side in the flow of the combustion gas flowing in the combustion gas passage 13 and the flue 14.
Inside the combustion gas passage 13, superheaters 41, 42, 43, reheaters 44, 45, a economizer 46, etc. are provided. It has a vertical portion 13b.
The flue 14 includes a first horizontal portion 14a that bends from the lower end of the vertical portion 13b of the combustion gas passage 13 and extends in the horizontal direction, and a first vertical portion 14b that bends from the downstream end of the first horizontal portion 14a and extends upward. A second horizontal portion 14c bends from the upper end of the first vertical portion 14b and extends in the horizontal direction, and a second vertical portion 14d bends from the downstream end of the second horizontal portion 14c and extends downward. There is. The second vertical portion 14d is provided with a denitrification catalyst 58, which will be described later. The downstream end of the second vertical portion 14d is connected to the upstream end of the gas duct 48 (see FIG. 1).
The combustion gas discharged from the furnace 11 flows through the horizontal part 13a and the vertical part 13b of the combustion gas passage 13, the first horizontal part 14a, the first vertical part 14b, and the second part of the flue 14, as shown by the arrows in FIG. It flows in the order of the horizontal portion 14c and is guided to the denitrification device 50.

Furthermore, in this embodiment, the combustion gas passage 13 may include a first hopper 13c provided vertically below the vertical portion 13b, and a second hopper 14e provided vertically below the first vertical portion 14b. A part of the coarse ash (combustion product) A contained in the combustion gas falls and is collected in the first hopper 13c and the second hopper 14e.

Further, in this embodiment, a first screen 18 may be provided inside the combustion gas passage 13 along an inclined surface formed at the lower end of the vertical portion 13b. Further, inside the flue 14, a second screen 15 may be provided at the upstream end of the first horizontal portion 14a so as to cover the entire cross section of the flow path of the first horizontal portion 14a. Further, a third screen 16 extending obliquely upward from the side wall may be provided at the lower end of the first vertical portion 14b. Further, a fourth screen 17 may be provided at an intermediate position of the first vertical portion 14b so as to cover a part of the flow path cross section of the first vertical portion 14b. Specifically, the fourth screen 17 covers a part of the flow path cross section of the first vertical section 14b on the second vertical section 14d side. The first screen 18, the second screen 15, the third screen 16, and the fourth screen 17 each reduce the flow velocity of the coarse ash A by contacting with the coarse ash A contained in the combustion gas, and This has the effect of guiding the ash A to the first hopper 13c or the second hopper 14e located below each screen.

Further, in the present embodiment, the flue 14 has a partition at least in the second vertical portion 14d where the denitrification catalyst 58 and the like are provided, as shown in the flow path cross section (EE cross section) of the flue 14 in FIG. 3, for example. It may be divided into a plurality of (in this embodiment, 30 as an example) sections 14g by the plate 14f. In detail, the partition plate 14f may divide a plurality of sections 14g so that the flow path cross section of the flue 14 is divided.

As shown in FIG. 2, the denitrification device 50 includes an ammonia supply nozzle 55 provided in the middle of the first vertical section 14b and an ammonia supply nozzle 55 provided in the second vertical section 14d to collect coarse ash A contained in the combustion gas. A catalyst layer 57 is provided below the collecting portion 56 (in the downstream direction). The denitrification device 50 injects a reducing agent such as ammonia into the combustion gas using an ammonia supply nozzle 55, and causes the combustion gas injected with the reducing agent to pass through a denitration catalyst 58. Thereby, nitrogen oxides (NOx) contained in the combustion gas are promoted and reduced by the catalytic action of the catalyst layer 57, and the combustion gas is denitrated.

As shown in FIG. 2, the catalyst layer 57 is provided in the second vertical portion 14d. For example, three catalyst layers 57 are provided so as to be arranged in the vertical direction (upstream and downstream direction). In this embodiment, each catalyst layer 57 may be constituted by a plurality of denitrification catalysts 58 (see FIG. 4) arranged in compartments 14g divided by partition plates 14f. At least one denitrification catalyst 58 is arranged within each compartment 14g. That is, the denitrification catalyst 58 is arranged over substantially the entire cross section of the flue 14 . Each denitrification catalyst 58 has, for example, a rectangular cross-sectional shape, and as shown in FIG. It has a dividing portion 58b that divides the space into a plurality of (in this embodiment, 36 as an example) flow paths 58c. The cross section of the flow path 58c has a substantially square shape with each side measuring, for example, about 6 to 7 mm. That is, the denitrification catalyst 58 has a so-called honeycomb shape with a mesh opening (channel width of the channel 58c) of about 6 to 7 mm. Note that the denitrification catalyst 58 is not limited to a honeycomb shape, and may be, for example, a plurality of plate-shaped catalysts arranged with a predetermined gap.

As shown in FIGS. 6 and 7, the collecting section 56 includes a first wire mesh section 61, a second wire mesh section 62 provided downstream of the first wire mesh section 61, and an end portion of the first wire mesh section 61. and the end of the second wire mesh section 62, a first pedestal 64 to which the first wire mesh section 61 and the third wire mesh section 63 are fixed, and the second wire mesh section 62 are fixed. It has a second pedestal 65. The collecting section 56 collects ash contained in the combustion gas using each wire mesh section. In addition, FIG. 6 is a top view of the collection part 56 in the flow path cross section (FF cross section) of the flue 14, and the first wire mesh part 61 is shown as a square with a hatched pattern, and the second wire mesh part 62 is shown as a square with a hatched pattern. Note that the shape of the first wire mesh portion 61 when viewed from above may be, for example, a rectangle, a square, or a parallelogram. Further, the shape of the second wire mesh portion 62 when viewed from above may be, for example, a rectangle, a square, or a parallelogram. Further, the first wire mesh portion 61 and the second wire mesh portion 62 are selected based on the rectangular cross-sectional shape of the denitration catalyst 58, and are not necessarily limited to a rectangular shape to suit the cross-sectional shape of the denitration catalyst 58, but are triangular, triangular, etc. It may also be a polygon such as a pentagon or a hexagon.

The first wire mesh portion 61 is made of metal (for example, about 4 mm to 6 mm in this embodiment) with a mesh opening smaller than the particle size of the coarse ash A and which does not cause a large increase in passage resistance of combustion gas. Constructed by mesh (as stainless steel). The first wire mesh portion 61 is formed into a quadrangular shape (for example, a rectangular shape, a square shape, or a parallelogram shape) in plan view. The first wire mesh portion 61 is arranged so that its upper and lower surfaces are substantially horizontal. That is, the first wire mesh portion 61 is arranged to intersect with the direction in which combustion gas flows. Further, as shown in FIG. 8, the first wire mesh portion 61 is arranged such that its lower surface is spaced apart from the upper surface of the denitration catalyst 58 by a distance H1. That is, a space is formed between the lower surface of the first wire mesh portion 61 and the upper surface of the denitration catalyst 58, and the length of this space in the vertical direction is equal to the distance H1.

The second wire mesh portion 62 is made of metal (as an example, the mesh size is smaller than the particle size of the coarse ash A and has a mesh size that does not significantly increase the passage resistance of combustion gas (in this embodiment, about 4 mm to 6 mm). Constructed of mesh (stainless steel). The second wire mesh portion 62 is formed in the same shape as the first wire mesh portion 61. The upper surface of the second wire mesh section 62 is disposed below the upper surface of the first wire mesh section 61 (in the direction toward the denitration catalyst 58 side) so that the upper surface and the lower surface are substantially horizontal. That is, the second wire mesh portion 62 is arranged to intersect with the direction in which combustion gas flows. Further, as shown in FIG. 8, the second wire mesh portion 62 is arranged such that its lower surface is spaced apart from the upper surface of the denitration catalyst 58 by a distance H2. That is, a space is formed between the lower surface of the second wire mesh portion 62 and the upper surface of the denitration catalyst 58, and the length of this space in the vertical direction is equal to the distance H2. The distance H2 is shorter than the distance H1. Further, the distance H2 is set to be five times or more the opening of the denitrification catalyst 58. The distance H2 is preferably 200 mm or more. The distance H2 is such a distance that even if coarse ash A is collected in a part of the second wire mesh portion 62 and clogging occurs, a large drift in the combustion gas flowing into the denitrification catalyst 58 will not occur. be done.

As shown in FIG. 6, a plurality of first wire mesh sections 61 and second wire mesh sections 62 are provided. The plurality of first wire mesh sections 61 and second wire mesh sections 62 are arranged side by side so that their upper surfaces are aligned. Further, the first wire mesh portion 61 and the second wire mesh portion 62 are arranged continuously in a predetermined direction (in FIG. 6, the vertical direction in the drawing), which is one of the directions forming the horizontal plane. That is, the plurality of first wire mesh sections 61 and second wire mesh sections 62 are arranged linearly in one direction. Further, the plurality of first wire mesh portions 61 and second wire mesh portions 62 are provided over substantially the entire region of the flue 14 through which combustion gas flows in one direction. The first wire mesh portions 61 and the second wire mesh portions 62 adjacent to each other in a predetermined direction are arranged so that no gap is formed in a plan view. In this embodiment, as an example, an example in which six first wire mesh sections 61 and second wire mesh sections 62 are arranged in one direction is described, but one of the first wire mesh sections 61 and second wire mesh sections 62 The number of pieces lined up in the direction is not limited to six.

Further, the first wire mesh portions 61 and the second wire mesh portions 62 are arranged alternately in a cross direction (in the left-right direction in FIG. 6) that is a direction orthogonal to a predetermined direction among the directions forming the horizontal plane. Specifically, a row of first wire mesh portions 61 lined up in one direction and a row of second wire mesh portions 62 lined up in one direction are arranged so that from the end in the intersecting direction, the row of second wire mesh portions 62, the first wire mesh portion 61 The columns are arranged alternately over substantially the entire area in the cross direction.
The first wire mesh portion 61 and the second wire mesh portion 62 adjacent in the cross direction are arranged so that no gap is formed when the cross section of the flow path is viewed from above. That is, the first wire mesh section 61 and the second wire mesh section 62 are arranged side by side so as to form steps in the vertical direction. Note that the first wire mesh portion 61 and the second wire mesh portion 62 that are adjacent to each other in the cross direction may be arranged so that they partially overlap when the cross section of the flow path is viewed from above, or they may be arranged so that they are separated from each other. may be placed.

In this way, the first wire mesh section 61 and the second wire mesh section 62 each cover a part of the flow path cross section of the flue 14. Further, the first wire mesh portion 61 and the second wire mesh portion 62 cover substantially the entire region of the flow path cross section of the flue 14 through which combustion gas flows.
Further, the distance from the top surface of the second wire mesh section 62 to the top surface of the first wire mesh section 61 is 1 m or less. Preferably, the length is 60 cm or less. This distance is such that the coarse ash A is collected in a part of the first wire mesh section 61 and the second wire mesh section 62, and when the first wire mesh section 61 and the second wire mesh section 62 are to be maintained or cleaned, the second wire mesh section The setting may be such that the hand of a worker standing on the upper surface of the portion 62 can reach the upper surface of the first wire mesh portion 61.

The third wire mesh portion 63 is made of a metal mesh (for example, SUS) with a mesh opening smaller than the particle size of the coarse ash A (in the present embodiment, for example, about 4 mm to 6 mm). The third wire mesh portion 63 is formed in a rectangular shape. The third wire mesh portion 63 is arranged so that its side surfaces are substantially vertical. That is, the first wire mesh portion 61 is arranged along the direction in which combustion gas flows. The third wire mesh section 63 connects the first wire mesh section 61 and the second wire mesh section 62 which are adjacent to each other in the cross direction. Specifically, the third wire mesh section 63 connects the end of the first wire mesh section 61 on the second wire mesh section 62 side and the end of the second wire mesh section 62 on the first wire mesh section 61 side. That is, the third wire mesh portion 63 is disposed between the first wire mesh portion 61 and the second wire mesh portion 62 so as to intersect with the first wire mesh portion 61 and the second wire mesh portion 62.
Note that the third wire mesh portion 63 may be arranged such that the side surface thereof is inclined within +10° from the vertical direction. When the third wire mesh portion 63 is inclined, the first wire mesh portion 61 and the second wire mesh portion 62 adjacent in the cross direction may partially overlap or be separated from each other when the cross section of the flow path is viewed from above. It will be placed in

Note that the first wire mesh section 61, the second wire mesh section 62, and the third wire mesh section 63 may be configured by a plurality of meshes that overlap in the combustion gas flow direction. Furthermore, when the mesh is composed of a plurality of meshes, the openings of the meshes may be different. That is, it may be configured by a mesh having thick strands with a large opening and a mesh with thin strands having a predetermined opening. With this configuration, the first wire mesh section 61, the second wire mesh section 62 can maintain the function of collecting coarse ash A by the first wire mesh section 61, the second wire mesh section 62, and the third wire mesh section 63. And the rigidity of the third wire mesh portion 63 can be improved.

As shown in FIG. 5, the first frame 64 includes a first frame portion 64a, which is a rectangular frame-shaped member, and four first leg portions 64b extending downward from each corner of the first frame portion 64a. ,have.
The first frame portion 64a is a frame-like member that is square in plan view. That is, the first frame portion 64a defines a rectangular space inside in plan view. The first wire mesh portion 61 is fixed in the space inside the first frame portion 64a. Specifically, the inner peripheral part of the first frame part 64a and the outer peripheral part of the first wire mesh part 61 are fixed.

Each of the first leg portions 64b is a columnar member extending downward from the four corners (quadrangular corners when viewed from above) of the first frame portion 64a. The length of each first leg portion 64b is the same as the distance H1. A fitting portion (not shown) that fits into the partition plate 14f provided inside the flue 14 is provided at the lower end of each first leg portion 64b. By fitting this fitting portion with the partition plate 14f, the first mount 64 is fixed to the flue 14 via the partition plate 14f.

Further, a third wire mesh portion 63 is provided between the first leg portions 64b adjacent to each other in one direction. The third wire mesh portion 63 connects the first leg portions 64b adjacent to each other in one direction. The third wire mesh portion 63 is arranged in a space defined by a first frame portion 64a, a second frame portion 65a (described later), and an adjacent first leg portion 64b. That is, the third wire mesh portion 63 is fixed to the first frame portion 64a, the second frame portion 65a, and the adjacent first leg portion 64b. Further, a fourth wire mesh portion 66 is provided between the first leg portions 64b adjacent to each other in the cross direction. Note that the fourth wire mesh portion 66 may be omitted.

As shown in FIG. 7, the second frame 65 includes a second frame portion 65a that is a rectangular frame-shaped member, and four second leg portions 65b extending downward from each corner of the second frame portion 65a. ,have.
The second frame portion 65a is a member having the same shape as the first frame portion 64a. The second wire mesh portion 62 is fixed in the space inside the second frame portion 65a. Specifically, the inner peripheral part of the second frame part 65a and the outer peripheral part of the second wire mesh part 62 are fixed.

Each second leg portion 65b is a columnar member that extends downward from four corners (quadrangular corners when viewed from above) of the second frame portion 65a. The length of each second leg portion 65b is the same as the distance H2. At the lower end of each second leg portion 65b, a fitting portion (not shown) that fits into a partition plate 14f provided inside the flue 14 is provided, similarly to the first leg portion 64b. By fitting this fitting portion with the partition plate 14f, the second mount 65 is fixed to the flue 14 via the partition plate 14f. Further, a fifth wire mesh portion 67 is provided between adjacent second leg portions 65b. Note that the fifth wire mesh portion 67 may be omitted.

The first mount 64 and the second mount 65 are independent and separate bodies. In other words, the first pedestal 64 and the second pedestal 65 are not permanently connected and fixed, but are relatively movable.

In addition, in the above description, an example was explained in which the legs of each pedestal and the partition plate 14f are removably fixed by fitting them together, but it is also possible to permanently connect and fix the legs of each pedestal and the partition plate 14f. You don't have to. For example, the weight of the first frame 64 to which the first wire mesh section 61, the third wire mesh section 63, and the fourth wire mesh section 66 are fixed may be set to a weight that does not move even when exposed to the flow of combustion gas. . Even with this configuration, relative movement between the first frame 64 and the partition plate 14f during operation of the boiler can be restricted. Further, with this configuration, it is possible to omit the work of fixing the first mount 64 and the partition plate 14f, so the installation work of the first mount 64 can be simplified, and maintenance and cleaning can be simplified. It can also make it easier for workers to move around. Similarly, for the second frame 65, the weight of the second wire mesh portion 62 and the fifth wire mesh portion 67 in a fixed state may be set to a weight that does not move even when exposed to the flow of combustion gas.

Next, the flow of combustion gas in the collection section 56 will be explained. First, when the first wire mesh section 61 and the second wire mesh section 62 are not clogged, the combustion gas flowing through the flue 14 passes through the first wire mesh section 61 and the second wire mesh section 62. pass. At this time, the first wire mesh section 61 and the second wire mesh section 62 collect coarse ash A contained in the combustion gas. The combustion gas from which the coarse ash A has been removed in the first wire mesh section 61 and the second wire mesh section 62 is guided to the catalyst layer 57 and flows into the flow path 58c of the denitrification catalyst 58. When the first wire mesh portion 61 and the second wire mesh portion 62 begin to become clogged, combustion gas cannot pass through the clogged portions, and uneven flow begins to occur in the combustion gas flow. Gas circulation can be maintained to a certain extent. After that, when the number of clogged areas increases further and many areas become clogged, the pressure loss due to the flow of combustion gas increases and the flow of combustion gas is obstructed, causing the first wire mesh to become clogged. This creates a situation where combustion gas becomes difficult to flow through the portion 61 and the second wire mesh portion 62.
As shown in FIG. 8, a state where many areas of the first wire mesh section 61 and the second wire mesh section 62 are clogged means that the combustion gas passes through the first wire mesh section 61 and the second wire mesh section 62. This is a situation where it becomes difficult. In this case, the combustion gas flows around the first wire mesh section 61 and the second wire mesh section 62, as shown by the arrows in FIG. The combustion gas that has bypassed the first wire mesh section 61 and the second wire mesh section 62 passes through the space between the first wire mesh section 61 and the second wire mesh section 62 and wraps around vertically below the first wire mesh section 61. I can do it. At this time, since the third wire mesh section 63 is provided between the first wire mesh section 61 and the second wire mesh section 62, the combustion gas passes through the third wire mesh section 63. Therefore, the third wire mesh portion 63 can collect the coarse ash A contained in the combustion gas. The combustion gas that has gone around to the downstream side of the first wire mesh section 61 is guided to the catalyst layer 57. At this time, since the distance (distance H2) between the second wire mesh section 62 and the denitrification catalyst 58 is sufficiently large, the combustion gas that has passed through the third wire mesh section 63 is sufficiently diffused before reaching the denitration catalyst 58. . A part of the diffused combustion gas goes around vertically below the second wire mesh section 62. The combustion gas guided to the catalyst layer 57 flows into the flow path 58c of the denitrification catalyst 58.

Next, a method for installing the collection section 56 within the flue 14 will be explained.
First, the first mount 64 and the second mount 65 are assembled. Next, wire mesh portions having predetermined openings are fixed to predetermined locations on the first mount 64 and the second mount 65. The assembly work of the first mount 64 and the second mount 65 and the fixing work of each wire mesh part may be performed not in the flue 14 but at another location. Next, the first mount 64 and the second mount 65 to which the wire mesh portions are fixed are carried into the flue 14 and fixed one by one to the partition plate 14f so that they are arranged in a predetermined manner. At this time, by fitting the fitting parts provided on the first mount 64 and the second mount 65 with the fitting parts on the partition plate 14f side, the first mount 64 and the second mount 65 and the partition plate 14f are connected. Fix it.
The first leg portion 64b of the first pedestal 64 and the second leg portion 65b of the second pedestal 65 have different lengths. Therefore, by installing the first mount 64 and the second mount 65 in this way, the distance H1 between the first wire mesh section 61 fixed to the first mount 64 and the denitration catalyst 58 and the distance H1 fixed to the second mount 65 can be adjusted. The first wire mesh portion 61 and the second wire mesh portion 62 can be installed inside the flue 14 such that the distance H2 between the second wire mesh portion 62 and the denitrification catalyst 58 is different from each other.

According to this embodiment, the following effects are achieved.
In this embodiment, the distance H1 between the first wire mesh section 61 and the denitration catalyst 58 is different from the distance H2 between the second wire mesh section 62 and the denitration catalyst 58. That is, the first wire mesh section 61 and the second wire mesh section 62 are separated from each other in the combustion gas flow direction. Thereby, a space is formed between the first wire mesh section 61 and the second wire mesh section 62. Further, in this embodiment, the first wire mesh section 61 and the second wire mesh section 62 each cover a part of the flow path cross section of the flue 14. That is, the first wire mesh portion 61 and the second wire mesh portion 62 each do not cover the entire area of the flow path cross section of the flue 14 . As a result, even if many areas of the first wire mesh section 61 and the second wire mesh section 62 are clogged with the collected coarse ash A, etc., combustion cannot pass through the first wire mesh section 61 and the second wire mesh section 62. The gas can bypass the first wire mesh section 61 and the second wire mesh section 62 and flow through the space between the first wire mesh section 61 and the second wire mesh section 62. The combustion gas that has bypassed the first wire mesh section 61 and the second wire mesh section 62 passes through the space between the first wire mesh section 61 and the second wire mesh section 62, and also passes through the space between the first wire mesh section 61 and the second wire mesh section 62. distributed downstream. Therefore, even if the first wire mesh section 61 and the second wire mesh section 62 are clogged, the combustion gas can be guided to the denitrification catalyst 58. Therefore, the denitrification reaction can be continuously performed in the denitrification catalyst 58.
Further, the first wire mesh portion 61 and the second wire mesh portion 62 are arranged to intersect with the combustion gas flow. Therefore, when many areas of the first wire mesh section 61 and the second wire mesh section 62 are not clogged, the combustion gas passes through the first wire mesh section 61 or the second wire mesh section 62. Therefore, the coarse ash A can be suitably collected by the first wire mesh section 61 and the second wire mesh section 62.

Further, in this embodiment, the distance H2 between the second wire mesh portion 62 and the denitration catalyst 58 is set to be five times or more the opening of the denitration catalyst 58. Thereby, the combustion gas that has bypassed the second wire mesh portion 62 is suitably diffused before reaching the denitrification catalyst 58. Therefore, it is possible to prevent the combustion gas from flowing unevenly into some of the plurality of flow paths of the denitrification catalyst 58.

In addition, for example, if the entire area of the collection part is made up of a flat mesh, if part of the flat mesh becomes clogged, combustion gas will pass through the clogged area. As a result, the combustion gas is diverted to areas where no clogging occurs. This may cause combustion gas to concentrate in a certain area. Further, at this time, coarse ash A begins to concentrate in other areas that are not clogged with the flow of combustion gas, making the planar mesh more likely to clog. In addition, as the clogging progresses and the remaining areas that are not clogged become even smaller, the flow of combustion gas and the concentration of coarse ash A progresses, causing clogging to occur in the entire area of the planar mesh. It may take a short amount of time.
In this way, when the combustion gas concentrates in a certain area in the collection section, the combustion gas is also biasedly guided to the denitrification catalyst disposed downstream of the collection section. If the combustion gas is unevenly guided to the denitrification catalyst, there is a possibility that the pressure drop passing through the denitrification catalyst will increase, and the reaction time will be reduced due to uneven distribution of the denitrification reaction area in areas where the combustion gas is concentrated, and the denitrification performance will be fully demonstrated. There is a possibility that it will not be done. In addition, denitrification catalyst deterioration may be accelerated, and concentrated combustion gas increases the density of coarse ash A and the flow velocity, so wear of the denitrification catalyst is likely to progress and the life of the denitrification catalyst is shortened. There is a possibility that it will happen.

In this embodiment, when many areas of the first wire mesh section 61 and the second wire mesh section 62 become clogged, the combustion gas is circulated through a new flow path passing through the third wire mesh section 63. This makes it possible to prevent combustion gas from concentrating on other areas that are not clogged. Further, as described above, the distance H2 between the second wire mesh portion 62 and the denitrification catalyst 58 is set to be at least five times the opening of the denitrification catalyst 58, so that the combustion gas is suitably diffused before reaching the denitrification catalyst 58. ing. Thereby, it is possible to suppress a situation in which combustion gas is unevenly guided to the denitrification catalyst 58. Therefore, an increase in pressure loss passing through the denitrification catalyst 58 can be suppressed. Moreover, it is possible to suppress a situation in which the reaction time is reduced and the denitrification performance is not fully exhibited. Further, acceleration of deterioration of the denitrification catalyst 58 can be suppressed. Further, since the progress of wear of the denitration catalyst 58 can be suppressed, the life of the denitration catalyst 58 can be extended.

Further, in the present embodiment, the first wire mesh section 61 and the second wire mesh section 62 cover substantially the entire cross section of the flow path in the area where the combustion gas of the flue 14 flows. As a result, when the first wire mesh portion 61 and the second wire mesh portion 62 are not clogged, coarse ash A is preferably captured in the entire flow path cross section of the area where the combustion gas of the flue 14 flows. can be collected. On the other hand, even if many areas of the first wire mesh section 61 and the second wire mesh section 62 are clogged, the combustion gas that cannot pass through the first wire mesh section 61 and the second wire mesh section 62, as described above, Bypassing the first wire mesh section 61 and the second wire mesh section 62 and passing through the space between the first wire mesh section 61 and the second wire mesh section 62 to the downstream side of the first wire mesh section 61 and the second wire mesh section 62 circulate. Therefore, the combustion gas can be guided to the denitrification catalyst 58 and denitrification can be performed in the denitrification catalyst 58.

Furthermore, the present embodiment includes a third wire mesh section 63 provided between the first wire mesh section 61 and the second wire mesh section 62. Thereby, the coarse ash A contained in the combustion gas passing through the space between the first wire mesh section 61 and the second wire mesh section 62 can be collected by the third wire mesh section 63. Therefore, many areas of the first wire mesh section 61 and the second wire mesh section 62 are clogged, and the combustion gas passes through the third wire mesh section 63 between the first wire mesh section 61 and the second wire mesh section 62. Even when the combustion gas passes through the space between the first wire mesh section 61 and the second wire mesh section 62, the coarse ash A contained in the combustion gas can be collected. Therefore, since the coarse ash A introduced to the denitrification catalyst 58 can be reduced, denitrification can be suitably performed in the denitrification catalyst 58.

Further, in this embodiment, the first wire mesh section 61 and the second wire mesh section 62 are fixed to the first mount 64 and the second mount 65. Thereby, the first wire mesh section 61 and the second wire mesh section 62 can be placed at predetermined positions simply by providing the first mount 64 and the second mount 65 at predetermined positions within the flue 14. Therefore, it is possible to omit the work of adjusting the positions of the first wire mesh section 61 and the second wire mesh section 62 so that they are at predetermined positions in the flue 14. Therefore, the installation work of the first wire mesh section 61 and the second wire mesh section 62 can be simplified.

Further, in this embodiment, the first mount 64 that fixes the first wire mesh portion 61 in a predetermined position and the second mount 65 that fixes the second wire mesh portion 62 in a predetermined position are separate bodies. Thereby, the first pedestal 64 and the second pedestal 65 can be moved separately. Therefore, compared to the case where the first mount 64 and the second mount 65 are integrated, the arrangement of the first wire mesh section 61 and the second wire mesh section 62 can be easily changed, and cleaning, maintenance, etc. It can also make it easier for workers to move around.

Further, for example, when performing cleaning or maintenance of each wire mesh section, a worker may perform the work while riding on the first wire mesh section 61. In this embodiment, the plurality of first wire mesh sections 61 are arranged so that their upper surfaces are continuously aligned in one direction. Thereby, the worker on the first wire mesh section 61 can easily move along one direction. Therefore, the work efficiency of the worker can be improved.

Further, in this embodiment, the distance between the first wire mesh section 61 and the second wire mesh section 62 in the combustion gas flow direction is 1 m or less. Thereby, a worker working on the first wire mesh section 61 can easily reach the second wire mesh section 62. Therefore, for example, when a worker on the first wire mesh section 61 cleans the second wire mesh section 62, the worker can easily perform the cleaning work.

Further, in this embodiment, the third wire mesh portion 63 is arranged substantially vertically. By arranging the third wire mesh section 63 substantially vertically in this manner, it is possible to make it difficult for the coarse ash A collected on the third wire mesh section 63 to accumulate. Therefore, clogging starting from the third wire mesh portion 63 can be suppressed. Therefore, it is possible to suppress a situation in which all of the first wire mesh section 61, the second wire mesh section 62, and the third wire mesh section 63 become clogged and the flow of combustion gas is extremely inhibited.

[Modified example]
Next, a modification of this embodiment will be described using FIGS. 9 and 10.
This modification differs from the above embodiment in the arrangement of the first pedestal 64 to which the first wire mesh portion 61 and the like are fixed, and the second pedestal 65 to which the second wire mesh portion 62 is fixed. The other configurations are the same as those in the above embodiment, so the same reference numerals are given and detailed explanation thereof will be omitted.
In the collection unit 70 according to this modification, as shown in FIGS. 9 and 10, the first mount 64 and the second mount 65 are arranged in a staggered manner. Specifically, the first mounts 64 and the second mounts 65 are arranged alternately in a predetermined direction (vertical direction in the paper in FIG. 9) and alternately in a cross direction (in the horizontal direction in the paper in FIG. 9). There is.

With this configuration, not only the third wire mesh portion 63 but also the fourth wire mesh portion 66 provided between the first leg portions 64b adjacent to each other in the cross direction are connected to the first wire mesh portion 61 and the second wire mesh. 62. That is, when the first wire mesh section 61 and the second wire mesh section 62 become clogged, the combustion gas can also be guided to the downstream side of the collection section 70 by the flow path passing through the fourth wire mesh section 66. . Therefore, it is possible to increase the area of the flow path through which the combustion gas flows when the first wire mesh section 61 and the second wire mesh section 62 become clogged. Therefore, even if the first wire mesh section 61 and the second wire mesh section 62 are clogged, the combustion gas can be guided to the denitrification catalyst 58 more suitably.

Note that the present disclosure is not limited to the above embodiments, and can be modified as appropriate without departing from the gist thereof.
For example, the collection section 56 of the embodiment described above and the collection section 70 of the modified example may be combined.

Further, for example, in the above embodiment, an example has been described in which the third wire mesh portion 63 is provided between the first wire mesh portion 61 and the second wire mesh portion 62, but the third wire mesh portion 63 may not be provided.

Further, although an example has been described in which the first wire mesh portion 61, the second wire mesh portion 62, and the third wire mesh portion 63 have a rectangular shape, the present disclosure is not limited thereto. The first wire mesh section 61, the second wire mesh section 62, and the third wire mesh section 63 may have, for example, a square shape or a triangular shape. Moreover, other polygonal shapes may be used. Alternatively, it may be circular.

Further, in the above embodiment, an example has been described in which the first wire mesh portion 61 and the second wire mesh portion 62 are provided over substantially the entire cross section of the flow path in the region where the combustion gas of the flue 14 flows, but the present disclosure is limited to this. Not done. It is also possible to specify areas where clogging is likely to occur based on operating conditions, etc., and to provide the first wire mesh section 61 and the second wire mesh section 62 only in the areas where clogging is likely to occur. In this case, a flat wire mesh portion may be provided in areas other than the areas where clogging is likely to occur, or the wire mesh portion itself may not be provided.

Furthermore, a rectifying grid 59 (see FIG. 11) may be provided between the collecting section 56 and the denitrification catalyst 58 to adjust the flow of combustion gas. When the rectifying grid 59 is provided, at least one rectifying grid 59 is arranged in each section 14g (see FIG. 3) of the flue 14, similarly to the denitrification catalyst 58. That is, the rectifying grid 59 is arranged over substantially the entire cross section of the flow path in the area where the combustion gas of the flue 14 flows. At this time, the distance between the lower surface of the second wire mesh section 62 and the upper surface of the rectifying grid 59 is approximately the same as the distance H2 between the lower surface of the second wire mesh section 62 and the upper surface of the denitrification catalyst 58 in the first embodiment. You can also set it as follows. As shown in FIG. 11, each rectifying grating 59 has an outer frame portion 59a which is a rectangular frame body, and a plurality of flow paths (in this embodiment, 36 as an example) in a space partitioned by the outer frame portion 59a. It has a lattice portion 59b that is divided into 59c. A flow path 59c defined by the outer frame portion 59a and the lattice portion 59b penetrates in the vertical direction, and the combustion gas flows therethrough. The cross section of the flow path 59c is approximately square with each side being about 10 mm. When the rectifying grid 59 is provided, the first mount 64 and the second mount 65 may be fixed to the partition plate 14f that partitions each section 14g in which the rectifying grid 59 is provided.

Further, in the embodiment described above, an example was described in which the horizontally arranged wire mesh portions of the collection unit 56 are only the first wire mesh portion 61 and the second wire mesh portion 62, but the present disclosure is not limited thereto. For example, a wire mesh portion may be provided whose distance from the denitrification catalyst 58 is different from both the first wire mesh portion 61 (distance H1) and the second wire mesh portion 62 (distance H2).

Further, in the above-described embodiment, the boiler in which the combustion gas contains combustion products is a coal-fired boiler, but the solid fuel may include biomass fuel, PC (petroleum coke) fuel generated during oil refining, It may also be a boiler that uses petroleum residue or the like. Moreover, not only solid fuel but also liquid fuel such as heavy oil can be used as the fuel, and the present invention can also be applied to mixed combustion of these fuels.

The denitrification device, the boiler system, and the installation method of the denitrification device described in each of the embodiments described above can be understood, for example, as follows.

Further, the denitrification device (50) according to one aspect of the present disclosure is provided inside a flue (14) through which combustion gas discharged from the furnace (11) of the boiler (10) flows, and denitrifies the combustion gas. A denitrification device (50) comprising a denitrification catalyst (58) through which the combustion gas passes, and a denitrification catalyst (58) arranged so as to intersect with the flow of the combustion gas on the upstream side of the denitrification catalyst (58) in the flow of the combustion gas. a first wire mesh section (61) that is arranged and covers a part of the flow path cross section of the region of the flue (14) through which the combustion gas flows, and collects combustion products contained in the combustion gas; A part of the flow path cross section of the flue (14) in a region where the combustion gas flows, and is disposed upstream of the denitrification catalyst (58) in the flow of the combustion gas so as to intersect with the flow of the combustion gas. a second wire mesh section (62) that covers the first wire mesh section and collects combustion products contained in the combustion gas; The distance between the second wire mesh portion (62) and the denitrification catalyst (58) is different.

In the above configuration, the distance between the first wire mesh section and the denitration catalyst is different from the distance between the second wire mesh section and the denitration catalyst. That is, the first wire mesh portion and the second wire mesh portion are separated from each other in the combustion gas flow direction. Thereby, a space is formed between the first wire mesh section and the second wire mesh section. Further, in the above configuration, the first wire mesh section and the second wire mesh section each cover a part of the flow path cross section of the flue. That is, the first wire mesh portion and the second wire mesh portion each do not cover the entire area of the cross section of the flow path in the region through which the combustion gas of the flue flows. As a result, if many areas of the first wire mesh section and the second wire mesh section are clogged with the collected combustion products, etc., the combustion gas that cannot pass through the first wire mesh section and the second wire mesh section will be transferred to the first wire mesh section. and circulates so as to bypass the second wire mesh section. The combustion gas that has bypassed the first wire mesh section and the second wire mesh section passes through the space between the first wire mesh section and the second wire mesh section, and also flows to the downstream side of the first wire mesh section and the second wire mesh section. . Therefore, even if the first wire mesh section and the second wire mesh section are clogged, the combustion gas can be guided to the denitrification catalyst. Therefore, the denitrification reaction can be continuously performed in the denitrification catalyst.
Further, the first wire mesh portion and the second wire mesh portion are arranged to intersect with the combustion gas flow. Therefore, when many areas of the first wire mesh section and the second wire mesh section are not clogged, the combustion gas passes through the first wire mesh section or the second wire mesh section. Therefore, combustion products can be suitably collected by the first wire mesh section and the second wire mesh section.

Further, in the denitrification device according to one aspect of the present disclosure, the first wire mesh portion (61) and the second wire mesh portion (62) cover the entire area of the flow path cross section of the flue (14). .

In the above configuration, the first wire mesh portion and the second wire mesh portion cover the entire cross section of the flow path in the area where the combustion gas of the flue flows. As a result, when many areas of the first wire mesh section and the second wire mesh section are not clogged, foreign matter can be suitably collected in the entire flow path cross section of the region where the combustion gas of the flue flows. be able to. On the other hand, even if many areas of the first wire mesh section and the second wire mesh section are clogged, the combustion gas that cannot pass through the first wire mesh section and the second wire mesh section will not pass through the first wire mesh section and the second wire mesh section. The liquid flows through the space between the first wire mesh section 61 and the second wire mesh section 62 to the downstream side of the first wire mesh section and the second wire mesh section. Therefore, the combustion gas can be guided to the denitrification catalyst and denitrification can be performed in the denitrification catalyst.

Further, the denitrification device according to one aspect of the present disclosure is provided between the first wire mesh section (61) and the second wire mesh section (62), and the first wire mesh section (61) and the second wire mesh section A third wire mesh section (63) is provided, which is arranged to intersect with the section (62) and collects combustion products contained in the combustion gas.

The above configuration includes a third wire mesh section provided between the first wire mesh section and the second wire mesh section. Thereby, combustion products contained in the combustion gas passing through the space between the first wire mesh section and the second wire mesh section can be collected by the third wire mesh section. Therefore, even if many areas of the first wire mesh section and the second wire mesh section are clogged and the combustion gas passes through the space between the first wire mesh section and the second wire mesh section, the combustion gas contains combustion products can be collected. Therefore, the amount of combustion products introduced to the denitrification catalyst can be reduced, so that denitrification can be suitably performed in the denitrification catalyst.

Further, the denitrification device according to one aspect of the present disclosure includes a pedestal for fixing the first wire mesh portion (61) and the second wire mesh portion (62) at predetermined positions.

In the above configuration, the first wire mesh section and the second wire mesh section are fixed to the pedestal. Thereby, the first wire mesh section and the second wire mesh section can be placed at predetermined positions simply by providing the frame to which the first wire mesh section and the second wire mesh section are fixed at predetermined positions within the flue. Therefore, it is possible to omit the work of adjusting the positions of the first wire mesh section and the second wire mesh section so that they are at predetermined positions in the flue. Therefore, the installation work of the first wire mesh section and the second wire mesh section can be simplified.

Further, in the denitrification device according to one aspect of the present disclosure, the mount includes a first mount (64) that fixes the first wire mesh portion (61) in a predetermined position, and a first mount that fixes the second wire mesh portion (62) in a predetermined position. a second pedestal (65) fixed at the position, and the first pedestal (64) and the second pedestal (65) are separate bodies.

In the above configuration, the first mount that fixes the first wire mesh portion in a predetermined position and the second mount that fixes the second wire mesh portion in a predetermined position are separate bodies. Thereby, the first mount and the second mount can be moved separately. Therefore, compared to the case where the first frame and the second frame are integrated, the arrangement of the first wire mesh section and the second wire mesh section can be easily changed, and the operator can easily change the arrangement of the first wire mesh section and the second wire mesh section when cleaning or maintenance. It can also make it easier to move.

Further, in the denitrification device according to one aspect of the present disclosure, the first wire mesh portion (61) and/or the second wire mesh portion (62) include a plurality of wire meshes with different mesh sizes, which overlap in the flow direction of the combustion gas. ing.

In the above configuration, in the first wire mesh portion and/or the second wire mesh portion, a plurality of wire meshes with different mesh sizes overlap in the combustion gas flow direction. This makes it possible to improve the rigidity of the first wire mesh section and/or the second wire mesh section while maintaining the ability of the first wire mesh section and/or the second wire mesh section to capture combustion products contained in combustion gas. can. The first wire mesh section and/or the second wire mesh section may be composed of a thick mesh of wires with a large opening and a thin mesh of wires with a predetermined opening.

Further, in the denitrification device according to one aspect of the present disclosure, a plurality of the first wire mesh portions (61) are provided, and each of the plurality of first wire mesh portions (61) has a plurality of first wire mesh portions (61). The upper surfaces are arranged so as to be continuous in one direction.

For example, when performing maintenance or the like on the denitration equipment, a worker may perform the work while riding on the first wire mesh section. In the above configuration, the plurality of first wire mesh portions are arranged so that their upper surfaces are continuously aligned in one direction. Thereby, the worker on the first wire mesh part can easily move along one direction. Therefore, the work efficiency of the worker can be improved.

Further, in the denitrification device according to one aspect of the present disclosure, the denitrification catalyst (58) has a plurality of flow paths (58c) through which the combustion gas passes, and the second wire mesh portion (62) has a plurality of channels (58c) through which the combustion gas passes. The distance (H2) between the second wire mesh portion (62) and the denitration catalyst (58) is located closer to the denitrification catalyst (58) than the first wire mesh portion (61), and the distance (H2) between the second wire mesh portion (62) and the denitration catalyst (58) is It is more than 5 times the width of .

In the above configuration, the distance between the second wire mesh portion and the denitrification catalyst is five times or more the width of the flow path of the denitrification catalyst. Thereby, the combustion gas that has bypassed the second wire mesh portion is suitably diffused before reaching the denitrification catalyst. Therefore, it is possible to prevent the combustion gas from flowing unevenly into some of the plurality of flow paths of the denitrification catalyst.

Further, in the denitrification device according to one aspect of the present disclosure, the second wire mesh portion (62) is disposed closer to the denitrification catalyst (58) than the first wire mesh portion (61), and the second wire mesh portion (62) The distance between the part (61) and the second wire mesh part (62) in the combustion gas flow direction is 1 m or less.

In the above configuration, the distance between the first wire mesh section and the second wire mesh section in the combustion gas flow direction is 1 m or less. Thereby, a worker working on the first wire mesh section can easily reach the second wire mesh section. Therefore, for example, when a worker on the first wire mesh section cleans the second wire mesh section, the worker can easily clean the second wire mesh section.

A boiler system according to an aspect of the present disclosure includes a coal-fired boiler (10) that generates combustion gas and generates steam using the combustion gas, and the denitrification device (50) according to any one of the above. We are prepared.

A method for installing a denitrification device according to one aspect of the present disclosure is that the denitration device is installed inside a flue (14) through which combustion gas discharged from a furnace (11) of a coal-fired boiler (10) flows, and the denitrification device is installed inside a flue (14) through which combustion gas is passed. a denitrification catalyst (58) disposed upstream of the denitrification catalyst (58) in the flow of the combustion gas so as to intersect with the flow of the combustion gas, and the combustion gas in the flue (14) flows through the denitrification catalyst (58). a first wire mesh part (61) that covers a part of the flow path cross section of the area where the combustion gas is formed and collects the combustion products contained in the combustion gas; is arranged to intersect with the flow of the combustion gas, covers a part of the cross section of the flow path in the region of the flue (14) through which the combustion gas flows, and captures combustion products contained in the combustion gas. A method for installing a denitrification device (50) for denitrifying the combustion gas, comprising: a second wire mesh portion (62) that collects the nitrification gas, the distance between the first wire mesh portion (61) and the denitration catalyst (58); The first wire mesh portion (61) and the second wire mesh portion (62) are connected to the flue (14) so that the distances between the second wire mesh portion (62) and the denitrification catalyst (58) are different. It has an installation process for installing it inside the.

10: Coal-fired boiler (boiler)
11: Furnace 12: Combustion device 13: Combustion gas passage 13a: Horizontal section 13b: Vertical section 13c: First hopper 14: Flue 14a: First horizontal section 14b: First vertical section 14c: Second horizontal section 14d: First 2 vertical section 14e: Second hopper 14f: Partition plate 14g: Section 15: Second screen 16: Third screen 17: Fourth screen 18: First screen 21: Combustion burner 22: Combustion burner 23: Combustion burner 24: Combustion Burner 25: Combustion burner 26: Pulverized coal supply pipe 27: Pulverized coal supply pipe 28: Pulverized coal supply pipe 29: Pulverized coal supply pipe 30: Pulverized coal supply pipe 31: Pulverizer 32: Pulverizer 33: Pulverizer 34: Grinding Machine 35: Pulverizer 36: Wind box 37: Air duct 38: Forced draft fan 39: Additional air port 40: Branch air duct 41: First superheater 42: Second superheater 43: Third superheater 44: Second Reheater 45 : First reheater 46 : Economizer 48 : Gas duct 49 : Air heater 50 : Denitration device 51 : Dust collector 53 : Desulfurization device 54 : Chimney 55 : Ammonia supply nozzle 56 : Collection part 57 : Catalyst Layer 58: Denitration catalyst 58a: Outer frame portion 58b: Divided portion 58c: Flow path 59: Rectifying grid 59a: Outer frame portion 59b: Grating portion 59c: Flow path 61: First wire mesh portion 62: Second wire mesh portion 63: First 3 wire mesh section 64: first mount 64a: first frame section 64b: first leg section 65: second mount 65a: second frame section 65b: second leg section 66: fourth wire mesh section 67: fifth wire mesh section 70 : Collection section

Claims (10)

The flue is provided inside a flue through which the combustion gas discharged from the furnace of the boiler flows, and is provided with a partition plate that extends in the vertical direction and divides the cross section of the flow path into a plurality of sections. A denitrification device that denitrates,
a denitrification catalyst through which the combustion gas passes;
It is disposed upstream of the denitrification catalyst in the flow of the combustion gas so as to intersect with the flow of the combustion gas, covers a part of the flow path cross section of the region of the flue through which the combustion gas flows, and a first wire mesh section that collects combustion products contained in the gas;
A combustion product contained in the combustion gas is disposed upstream of the denitration catalyst in the flow of the combustion gas so as to intersect with the flow of the combustion gas, and covers a part of the cross section of the flow path of the flue. a second wire mesh section that collects the
a pedestal for fixing the first wire mesh section and the second wire mesh section in predetermined positions ;
The distance between the first wire mesh portion and the denitration catalyst is different from the distance between the second wire mesh portion and the denitration catalyst,
In the denitrification device, a leg portion of the pedestal is provided with a fitting portion that fits into the partition plate . The denitrification device according to claim 1, wherein the first wire mesh portion and the second wire mesh portion cover the entire cross section of the flow path of the flue. Provided between the first wire mesh section and the second wire mesh section, arranged to intersect with the first wire mesh section and the second wire mesh section, and configured to collect combustion products contained in the combustion gas. The denitrification device according to claim 1 or 2, comprising a third wire mesh section. The mount includes a first mount that fixes the first wire mesh portion in a predetermined position, and a second mount that fixes the second wire mesh portion in a predetermined position,
The denitrification device according to any one of claims 1 to 3, wherein the first mount and the second mount are separate bodies. The denitrification device according to any one of claims 1 to 4 , wherein the first wire mesh portion and/or the second wire mesh portion include a plurality of wire meshes with different mesh sizes overlapping in the flow direction of the combustion gas. A plurality of the first wire mesh portions are provided,
Any one of claims 1 to 5 , wherein the plurality of first wire mesh portions are arranged such that upper surfaces of each of the first wire mesh portions facing upstream of the combustion gas are lined up continuously along one direction. The denitrification device described above. The denitrification catalyst has a plurality of flow paths through which the combustion gas passes,
The second wire mesh portion is disposed closer to the denitrification catalyst than the first wire mesh portion,
The denitrification device according to any one of claims 1 to 6 , wherein the distance between the second wire mesh portion and the denitrification catalyst is five times or more the width of the flow path. The second wire mesh portion is disposed closer to the denitrification catalyst than the first wire mesh portion,
The denitrification device according to any one of claims 1 to 7 , wherein the distance between the first wire mesh portion and the second wire mesh portion in the combustion gas flow direction is 1 m or less. a boiler that generates combustion gas and generates steam using the combustion gas;
The denitrification device according to any one of claims 1 to 8 ,
Boiler system with. The flue is provided inside a flue through which the combustion gas discharged from the furnace of the boiler flows, and is provided with a partition plate that extends in the vertical direction and divides the cross section of the flow path into a plurality of sections. a denitrification catalyst passing through;
It is disposed upstream of the denitrification catalyst in the flow of the combustion gas so as to intersect with the flow of the combustion gas, covers a part of the flow path cross section of the region of the flue through which the combustion gas flows, and a first wire mesh section that collects combustion products contained in the gas;
disposed upstream of the denitrification catalyst in the flow of the combustion gas so as to intersect with the flow of the combustion gas, covering a part of the cross section of the flow path in the region of the flue through which the combustion gas flows; a second wire mesh section that collects combustion products contained in the combustion gas;
a pedestal for fixing the first wire mesh section and the second wire mesh section in predetermined positions ;
A method for installing a denitrification device that denitrates the combustion gas, the method comprising:
The first wire mesh section and the second wire mesh section are placed inside the flue so that the distance between the first wire mesh section and the denitrification catalyst is different from the distance between the second wire mesh section and the denitration catalyst. The installation process to install ,
A method for installing a denitrification device, comprising a fitting step of fitting a fitting part provided on a leg of the pedestal to the partition plate.

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