JP7611722B2 - Denitrification device, frame, boiler, and denitrification catalyst installation method - Google Patents

Description

This disclosure relates to a denitration device, a stand and a boiler, and a method for installing a denitration catalyst.

Large boilers, such as power generation boilers, have a hollow furnace that is installed vertically, and multiple burners are arranged on the furnace wall along the circumferential direction of the furnace. In addition, in large boilers, a flue is connected vertically above the furnace, and a heat exchanger for generating steam is arranged in this flue. Then, a flame is formed when the burner injects a mixture of fuel and air (oxidizing gas) into the furnace, and combustion gas is generated and flows into the flue. A heat exchanger is installed in the area where the combustion gas flows, and water and steam flowing in the heat transfer tubes that make up the heat exchanger are heated to generate superheated steam. In addition, a denitration device is installed downstream of the heat exchanger in the flue to remove nitrogen oxides (NOx) from the combustion gas. An example of a boiler equipped with a denitration device is the boiler described in Patent Document 1.

Patent Document 1 describes a denitration reactor equipped with three catalyst support structures arranged in a vertical tier (three tiers), each supporting a number of catalyst blocks.

JP 2017-101860 A

However, in Patent Document 1, only one layer of catalyst blocks is provided for each catalyst support structure, so that it is necessary to provide the same number of catalyst support structures as the number of catalyst block layers, which may result in a complex structure.
In addition, the boiler may be provided with a floor (hereinafter referred to as a "working floor") for performing work on each catalyst (for example, catalyst installation work and maintenance work). In general, the height position of the working floor is provided at a height position that is approximately the same as the height position of the support member (for example, the catalyst support structure of Patent Document 1) that supports the catalyst with respect to the flue. In addition, the working floor is provided for each support member. Therefore, when a plurality of support members are provided, a plurality of working floors are also provided. When a plurality of working floors are provided, it is necessary to set the height so that the workers on each working floor can safely pass through, so that the interval between the working floors needs to be relatively long (for example, about 2 m). As described above, since the positions of the working floor and the support member are approximately the same position, if the interval between the working floors is set to a relatively long interval, the interval between the support members will also be adjusted to the interval between the working floors. As a result, the interval between the support members and the interval between the working floors will also be relatively long. In this way, it is necessary to set a relatively long interval between the support members. Therefore, the greater the number of support members, the longer the vertical length of the denitrification device will be. Therefore, when only one layer of catalyst is provided on the support member as in Patent Document 1, the number of support members is increased, which may increase the vertical length of the denitration device.

The present disclosure has been made in consideration of the above circumstances, and has an object to provide a denitration device, a frame and a boiler, and a method for installing a denitration catalyst that can simplify the structure.
Another object of the present disclosure is to provide a denitration device, a frame, a boiler, and a method for installing a denitration catalyst that can shorten the vertical length of the denitration device.

In order to solve the above problems, the denitration device, frame, boiler, and catalyst installation method of the present disclosure employ the following measures.
A denitration device according to one embodiment of the present disclosure is a denitration device that removes nitrogen oxides from combustion gas, and includes a first denitration catalyst provided inside a housing and through which combustion gas passes, a second denitration catalyst provided inside the housing below the first denitration catalyst and through which combustion gas that has passed through the first denitration catalyst passes, a stand provided between the first denitration catalyst and the second denitration catalyst for supporting the first denitration catalyst on the second denitration catalyst, and a support member that supports the second denitration catalyst relative to the housing.

A catalyst installation method according to one aspect of the present disclosure is a method for installing a denitration catalyst through which combustion gas passes, the denitration catalyst having a first denitration catalyst and a second denitration catalyst disposed below the first denitration catalyst, and including the steps of supporting the second denitration catalyst on a support member that supports the second denitration catalyst against the housing, providing a stand above the second denitration catalyst, and supporting the first denitration catalyst on the second denitration catalyst via the stand.

According to the present disclosure, the structure can be simplified.
In addition, the vertical length of the denitration device can be shortened.

1 is a schematic configuration diagram showing a coal-fired boiler according to an embodiment of the present disclosure. FIG. 1 is a side view showing a denitration device and a working structure according to an embodiment of the present disclosure. 1 is a plan view showing a denitration device and a working structure according to an embodiment of the present disclosure. FIG. 2 is a perspective view of a catalyst pack and a stand according to an embodiment of the present disclosure. FIG. 1 is a perspective view of a catalyst according to an embodiment of the present disclosure. FIG. 2 illustrates a cross-section of a lower portion of a catalyst pack according to an embodiment of the present disclosure. FIG. 5 is a plan view showing a main part (part A) of FIG. 4 . 8 is a cross-sectional view taken along the line CC in FIG. 7 . FIG. 5 is a plan view showing a main part (part B) of FIG. 4 . 10 is a cross-sectional view taken along the line D-D in FIG. 9 .

Below, a preferred embodiment of the present disclosure will be described with reference to the attached drawings. Note that the present disclosure is not limited to this embodiment, and when there are multiple embodiments, the present disclosure also includes configurations in which the respective embodiments are combined. In the following description, top and upward refer to the upper side in the vertical direction, and bottom and downward refer to the lower side in the vertical direction, and the vertical direction is not precise and includes error.

Figure 1 is a schematic diagram showing the configuration of a coal-fired boiler according to this embodiment.

The coal-fired boiler 10 of this embodiment is a coal-fired (pulverized coal-fired) boiler that uses pulverized coal (carbon-containing solid fuel) as pulverized fuel, burns this pulverized fuel with a burner, and exchanges the heat generated by this combustion with feed water or steam to generate superheated steam.

In this embodiment, as shown in FIG. 1, the coal-fired boiler 10 has a furnace 11, a combustion device 12, and a combustion gas passage 13. The furnace 11 has a hollow rectangular cylinder shape and is installed vertically. The furnace wall 101 that constitutes the furnace 11 is composed of multiple heat transfer tubes and fins that connect them, and exchanges heat generated by the combustion of pulverized fuel with water and steam flowing inside the heat transfer tubes to suppress the temperature rise of the furnace wall.

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 has multiple burners (e.g., 21, 22, 23, 24, 25) attached to the furnace wall. For example, the burners 21, 22, 23, 24, 25 are arranged at equal intervals along the circumferential direction of the furnace 11 as one set, and are arranged in multiple stages (e.g., five stages in FIG. 1) along the vertical direction. However, the shape of the furnace, the number of burners in one stage, the number of stages, the arrangement, etc. are not limited to this embodiment.

The burners 21, 22, 23, 24, 25 are connected to multiple pulverizers (mills) 31, 32, 33, 34, 35 via pulverized coal supply pipes 26, 27, 28, 29, 30. The pulverizers 31, 32, 33, 34, 35 are configured, for example, such that a pulverizer table (not shown) is supported in the pulverizer housing so that it can be driven and rotated, and multiple pulverizer rollers (not shown) are supported above the pulverizer table so that they can rotate in conjunction with the rotation of the pulverizer table. When coal is fed between the multiple pulverizer rollers and the pulverizer table, it is pulverized and transported by a carrier gas (primary air, oxidizing gas) to a classifier (not shown) in the pulverizer housing, and the pulverized fuel classified to a predetermined particle size range can be supplied from the pulverized coal supply pipes 26, 27, 28, 29, 30 to the burners 21, 22, 23, 24, 25.

Furnace 11 is also provided with a wind box 36 at the mounting positions of burners 21, 22, 23, 24, and 25, and one end of an air duct (airway) 37 is connected to this wind box 36. The other end of air duct 37 is provided with a forced draft fan (FDF: Forced Draft Fan) 38.

As shown in FIG. 1, the combustion gas passage 13 is connected to the vertical upper part of the furnace 11. The combustion gas passage 13 is provided with superheaters 102, 103, 104, reheaters 105, 106, and a coal economizer 107 as heat exchangers for recovering the heat of the combustion gas, and heat is exchanged between the combustion gas generated in the furnace 11 and the feed water and steam flowing inside each heat exchanger.

As shown in FIG. 1, the combustion gas passage 13 is connected to the flue 14 downstream, through which the combustion gas that has undergone heat exchange is discharged. An air heater (air preheater) 42 is provided between the flue 14 and the air duct 37, and heat is exchanged between the air flowing through the air duct 37 and the combustion gas flowing through the flue 14, thereby raising the temperature of the combustion air supplied to the burners 21, 22, 23, 24, and 25.

Further, the flue 14 is provided with a denitration device 43 at a position upstream of the air heater 42. The denitration device 43 supplies a reducing agent having an effect of reducing nitrogen oxides, such as ammonia or urea water, into the flue 14, and promotes a reaction between the nitrogen oxides in the combustion gas to which the reducing agent has been supplied and the reducing agent by the catalytic action of a denitration catalyst 112 (see FIG. 4 ) provided in the denitration device 43, thereby removing and reducing the nitrogen oxides in the combustion gas. Details of the denitration device 43 will be described later.
The gas duct 41 connected to the flue 14 is provided with a dust collector 44 such as an electric dust collector, an induced draft fan (IDF) 45, a desulfurization device 46, etc., downstream of the air heater 42, and a chimney 50 is provided at the downstream end.

On the other hand, when the multiple pulverizers 31, 32, 33, 34, 35 are driven, the generated pulverized fuel is supplied to the burners 21, 22, 23, 24, 25 through the pulverized coal supply pipes 26, 27, 28, 29, 30 together with the conveying gas (primary air, oxidizing gas). In addition, the exhaust gas discharged from the flue 14 is heat exchanged with the air heater 42, and the heated combustion air (secondary air, oxidizing gas) is supplied to the burners 21, 22, 23, 24, 25 from the air duct 37 through the wind box 36. The burners 21, 22, 23, 24, 25 blow a pulverized fuel mixture, which is a mixture of the pulverized fuel and the conveying gas, into the furnace 11 and also blow the combustion air into the furnace 11, at which 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 inside the furnace 11 and is discharged into the combustion gas passage 13. In this embodiment, air is used as the oxidizing gas. Gases with a higher or lower oxygen ratio than air may also be used, and can be used by optimizing the fuel flow rate.

Then, as shown in FIG. 1, the combustion gas is heat-exchanged in the second superheater 103, the third superheater 104, the first superheater 102 (hereinafter sometimes simply referred to as the superheater), the second reheater 106, the first reheater 105 (hereinafter sometimes simply referred to as the reheater), and the economizer 107 arranged in the combustion gas passage 13, and then discharged into the flue 14. Nitrogen oxides are reduced and removed in the denitrification device 43 arranged in the flue 14, and then heat-exchanged in the air heater 42 and discharged into the gas duct 41. Particulate matter is removed in the dust collector 44 arranged in the gas duct 41, and sulfur oxides are removed in the desulfurization device 46, and then the exhaust gas is discharged into the atmosphere from the chimney 50. 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, the details of the denitrification device 43 and the working structure will be described with reference to Figures 2 to 10. In the following description and in Figures 2 to 10, the vertical direction will be described as the Z-axis direction. Also, one of the horizontal directions will be described as the X-axis direction, and the direction perpendicular to the Z-axis direction and the X-axis direction will be described as the Y-axis direction. The Z-axis direction may also be referred to as the "up-down direction."

As shown in Figures 1 and 2, a denitration device 43 is provided midway along the portion of the flue 14 that extends in the Z-axis direction (hereinafter referred to as the "vertical portion 14a"). Also, as shown in Figure 2, a work structure 160 is provided adjacent to the denitration device 43.

The denitration device 43 comprises a housing 47 forming an outer shell, a plurality of first catalyst packs (first denitration catalyst) 110, a plurality of second catalyst packs (second denitration catalyst) 120 provided below the first catalyst packs 110, a plurality of third catalyst packs 130 provided below the second catalyst packs 120, a plurality of stands 140 provided between the first catalyst packs 110 and the second catalyst packs 120, and a plurality of steel frame parts (support members) 150 fixed to the housing 47.

As shown in FIG. 2, the housing 47 is a rectangular tubular member with openings at the top and bottom. The opening at the top of the housing 47 is connected to the upstream flue 14, and the opening at the bottom is connected to the downstream flue 14. The combustion gas that flows into the housing 47 from the opening at the top flows vertically inside the housing 47 and flows out from the opening at the bottom.

Further, a first catalyst pack 110, a second catalyst pack 120, and a third catalyst pack 130 are housed inside the housing 47. The combustion gas flowing inside the housing 47 passes through the first catalyst pack 110, the second catalyst pack 120, and the third catalyst pack 130. The first catalyst pack 110, the second catalyst pack 120, and the third catalyst pack 130 reduce and remove (denitrify) nitrogen oxides in the combustion gas passing through them.
Further, manholes are individually formed on the side of the housing 47 at positions corresponding to each of the catalyst packs 110, 120, 130. As shown in Fig. 3, the manhole 48 is provided at a height position between the first catalyst pack 110 and the second catalyst pack 120, for example. The manhole 48 can be switched between an open state and a closed state by an opening and closing door.

3, the multiple first catalyst packs 110 are arranged side by side so as to cover substantially the entire flow path cross section (cross section formed by the X-axis direction and the Y-axis direction) of the housing 47. Note that, in the present embodiment, an example is described in which five first catalyst packs are provided in the Y-axis direction and four first catalyst packs are provided in the X-axis direction (a total of 20 first catalyst packs), but the number of first catalyst packs 110 is not limited to this.
2, the first catalyst packs 110 are not stacked vertically. That is, the first catalyst packs 110 are arranged in a single layer. The length of the first catalyst pack 110 in the Z-axis direction is, for example, about 1 m.
Since the first catalyst packs 110 have the same structure, the structure of one of the first catalyst packs 110 will be described below as a representative example.

As shown in FIG. 4, the first catalyst pack 110 has a rectangular cylindrical frame portion 111 and a plurality of denitrification catalysts 112 (catalysts). The first catalyst pack 110 is supported from below by a stand 140. Details of the stand 140 will be described later.

As shown in FIG. 5, each denitration catalyst 112 has an outer frame 112a, which is a rectangular frame extending in the vertical direction (the direction of flow of the combustion gas), and partition walls 112b that divide the space defined by the outer frame 112a into multiple flow paths (16 in this embodiment, for example). Each denitration catalyst 112 has a so-called honeycomb shape. Note that the shape of the denitration catalyst 112 is not limited to a honeycomb shape. For example, the denitration catalyst 112 may be a plurality of plate-shaped catalysts arranged with a predetermined gap between them.

The rectangular frame portion 111 is a rectangular frame body extending in the up-down direction. The upper and lower ends of the rectangular frame portion 111 are open. The lower end of the rectangular frame portion 111 is provided with a flange portion 115 (see FIG. 8) that extends a predetermined distance toward the center. The flange portion 115 is provided over the entire circumferential area of the rectangular frame portion 111. The flange portion 115 has a rectangular frame shape.

As shown in FIG. 6, four catalyst receiving portions 116 are provided on the inner peripheral surface of the lower portion of the rectangular frame portion 111. Each catalyst receiving portion 116 is provided at one of the four corners of the rectangular frame portion 111. Each catalyst receiving portion 116 has a shape that forms a 90-degree arc when viewed in a plan view. The circumferential ends of each catalyst receiving portion 116 are fixed to the inner peripheral surface of the rectangular frame portion 111.

As shown in FIG. 6, a lattice-shaped catalyst pack structural member 117 is provided at the bottom of the rectangular frame 111. The catalyst pack structural member 117 is a member for supporting the catalyst 112 and maintaining the structure of the rectangular frame 111. The catalyst pack structural member 117 is fixed to the inner peripheral surface of the rectangular frame 111 and is provided so as to cover the entire cross section of the rectangular frame 111 when cut in a horizontal plane (XY plane). As shown in FIG. 8, the catalyst pack structural member 117 and the catalyst receiving portion 116 are provided at approximately the same height on their upper surfaces, and the denitration catalyst 112 is placed on the upper surface. In other words, the catalyst receiving portion 116 and the catalyst pack structural member 117 support the denitration catalyst 112 from below.

As shown in Fig. 2 etc., the second catalyst packs 120 are arranged side by side so as to cover substantially the entire cross section of the flow path of the housing 47, similar to the first catalyst packs 110. Moreover, the second catalyst packs 120 are not stacked in the vertical direction as shown in Fig. 2. That is, the second catalyst packs 120 are arranged in a single layer. Each second catalyst pack 120 is arranged vertically below each first catalyst pack 110.
The structure of each second catalyst pack 120 is the same as that of the first catalyst pack 110, and therefore a detailed description will be omitted. The second catalyst pack 120 supports the stand 140 from below. The second catalyst pack 120 is also supported from below by a steel frame section 150. Details of the steel frame section 150 will be described later.

Similar to the first catalyst pack 110 and the second catalyst pack 120, the third catalyst packs 130 are arranged side by side so as to cover substantially the entire area of the flow path cross section of the housing 47. Moreover, as shown in Fig. 2, the third catalyst packs 130 are not stacked in the vertical direction. That is, the third catalyst packs 130 are arranged in a single layer.
The structure of each of the third catalyst packs 130 is the same as that of the first catalyst pack 110, and therefore a detailed description thereof will be omitted. The third catalyst packs 130 are supported from below by a steel frame portion 150. The steel frame portion 150 will be described in detail later.

The multiple stands 140 are arranged between each of the first catalyst packs 110 and each of the second catalyst packs 120. Each stand 140 supports the first catalyst pack 110 on the second catalyst pack 120. Each stand 140 supports the first catalyst pack 110 from below. Each stand 140 is also supported by the second catalyst pack 120 from below. Each stand 140 also serves as a spacer that maintains a predetermined distance between the first catalyst pack 110 and the second catalyst pack 120 in the Z-axis direction. Since each stand 140 has the same structure, the structure of one stand 140 will be described below as a representative example.

As shown in FIG. 4, the stand 140 has a beam portion 141 extending horizontally and a plurality of pillar portions 142 extending vertically. As shown in FIGS. 7 to 10, the stand 140 also has a plurality of first restricting portions 143 that restrict horizontal movement with the first catalyst, and a locking portion 144 that is placed on the second catalyst.

As shown in FIG. 4, the beam portion 141 is a rectangular frame-shaped member made of a plate material with an opening in the central region. The plate material constituting the beam portion 141 is arranged so that the plate surface (the surface with the largest area) is a horizontal plane. The upper surface of the beam portion 141 is formed to be flat. As shown in FIG. 4, the first catalyst pack 110 is placed on the upper surface of the beam portion 141. In detail, as shown in FIG. 8, the rectangular frame portion 111 of the first catalyst pack 110 is placed on the upper surface of the beam portion 141 via the flange portion 115. At this time, the rectangular frame portion 111 is placed on the part of the upper surface of the beam portion 141 that is inside (toward the center) the inner circumferential surface of the column portion 142.

Furthermore, the length in the X-axis direction of the beam portion 141 is longer than the length in the X-axis direction of the rectangular frame portion 111 of the first catalyst pack 110. The length in the Y-axis direction of the beam portion 141 is longer than the length in the Y-axis direction of the rectangular frame portion 111 of the first catalyst pack 110. With this configuration, it is possible to easily place the first catalyst pack 110 on the upper surface of the beam portion 141.
8, the inner end of the beam portion 141 is located outside the inner end of the flange portion 115 of the rectangular frame portion 111. By configuring in this manner, it is possible to prevent the beam portion 141 from obstructing the flow of combustion gas from the first catalyst pack 110 to the second catalyst pack 120.

As shown in FIG. 4, the multiple (four in this embodiment) pillars 142 are provided at each of the four corners of the beam 141. More specifically, they extend downward from the outer ends of the four corners of the beam 141.

The upper end of each pillar 142 is rigidly joined to the lower surface of the beam 141. Specifically, the upper end of the pillar 142 and the lower surface of the beam 141 are fixed, for example, by welding. In other words, the frame 140 has a rigid frame structure. Since the structure of each pillar 142 is the same, the structure of one pillar 142 will be described below as a representative example.

The pillar portion 142 is an elongated member extending along the Z-axis direction. The pillar portion 142 is a member having an L-shaped cross section in the longitudinal direction (cross section when cut on the XY plane). The pillar portion 142 is disposed such that the corners of the L shape correspond to the corners of the beam portion 141.
An opening is provided between adjacent pillars 142. As described above, the frame 140 has a rigid frame structure. That is, no reinforcing members are provided to connect the pillars 142 to each other, or to connect the pillars 142 to the beams 141 (e.g., braces, etc.). Therefore, workers can enter the space inside the frame 140 through the opening between adjacent pillars 142. Furthermore, workers can easily move through the space between the first catalyst pack 110 and the second catalyst pack 120.

The length of the column 142 in the Z-axis direction is, for example, 500 mm. The length of the column 142 in the Z-axis direction is not limited to 500 mm. As described above, the stand 140 also serves as a spacer that maintains a predetermined distance between the first catalyst pack 110 and the second catalyst pack 120 in the Z-axis direction. Therefore, the length of the column 142 in the Z-axis direction is the distance between the first catalyst pack 110 and the second catalyst pack 120 in the Z-axis direction. Therefore, the length of the column 142 in the Z-axis direction is determined according to the desired distance between the first catalyst pack 110 and the second catalyst pack 120 in the Z-axis direction. The distance between the first catalyst pack 110 and the second catalyst pack 120 in the Z-axis direction is determined from the following perspective.

When the gap between the first catalyst pack 110 and the second catalyst pack 120 is narrow, clogging may occur in the DeNOx catalyst 112 of the second catalyst pack 120. This is because, when the gap between the first catalyst pack 110 and the second catalyst pack 120 is narrow, the combustion gas that has passed through the first catalyst pack 110 is not appropriately guided to the flow path of the DeNOx catalyst 112 of the second catalyst pack 120. The combustion gas that has passed through the first catalyst pack 110 has a flow velocity distribution in the X-Y cross section due to the influence of the dividing wall 112b. For example, if the flow rate recovery of the combustion gas that has passed through the first catalyst pack 110 is insufficient due to the narrow gap between the first catalyst pack 110 and the second catalyst pack 120, and the flow rate distribution in the X-Y cross section is not uniform when the combustion gas reaches the inlet of the second catalyst pack 120, in the region where the flow rate is low (where stagnation occurs), ash mixed in the combustion gas will adhere to and accumulate on the denitration catalyst 112 of the second catalyst pack 120, causing clogging of the denitration catalyst 112. For this reason, it is desirable that the gap between the first catalyst pack 110 and the second catalyst pack 120 in the Z-axis direction is such that clogging does not occur in the denitration catalyst 112 of the second catalyst pack 120. Specifically, it is desirable that the gap between the first catalyst pack 110 and the second catalyst pack 120 in the Z-axis direction is 500 mm or more. In addition, workers may enter between the first catalyst pack 110 and the second catalyst pack 120 for the purpose of maintenance or the like. For this reason, it is preferable that the distance in the Z-axis direction between the first catalyst pack 110 and the second catalyst pack 120 is at least as long as an operator can crawl into. From this viewpoint, it is preferable that the distance in the Z-axis direction between the first catalyst pack 110 and the second catalyst pack 120 is at least 500 mm.
Furthermore, the longer the distance in the Z-axis direction between the first catalyst pack 110 and the second catalyst pack 120, the longer the length in the Z-axis direction of the denitration device 43. If the length in the Z-axis direction of the denitration device 43 is long, not only will the denitration device 43 become larger, but it will also be a factor in increasing the size of the coal-fired boiler 10 in which the denitration device 43 is installed. For this reason, in order to avoid an increase in the size of the denitration device 43, it is desirable to set the distance in the Z-axis direction between the first catalyst pack 110 and the second catalyst pack 120 to be shorter than 2 m.
Thus, it is preferable that the distance in the Z-axis direction between the first catalyst pack 110 and the second catalyst pack 120 is 500 mm or more and shorter than 2 m. Therefore, it is preferable that the length in the Z-axis direction of the column portion 142 is also 500 mm or more and shorter than 2 m.

One first restricting portion 143 is provided on each column portion 142. As shown in Figs. 7 and 8, the first restricting portion 143 is provided on the upper end of the column portion 142. The first restricting portion 143 includes a cylindrical abutment portion 145 extending along the Z-axis direction, and two fixing portions 146 that fix the abutment portion 145 to the inner surface of the column portion 142.

As shown in Figures 7 and 8, each fixing portion 146 extends a predetermined distance from the inner surface of the column portion 142 along the X-axis direction or the Y-axis direction. The inner end (tip) of the fixing portion 146 is located more inward than the inner end of the beam portion 141. The inner end (tip) of the fixing portion 146 is also located slightly more inward than the inner end of the flange portion 115 of the first catalyst pack 110. The lower part of the abutment portion 145 is fixed to the inner end of the fixing portion 146.

As shown in FIG. 8, the abutment portion 145 extends upward from the fixed portion 146. The upper end of the abutment portion 145 is located above the beam portion 141. The upper end of the abutment portion 145 is located above the upper surface of the flange portion 115. The upper end of the abutment portion 145 is located slightly inside the inner end of the flange portion 115. Therefore, when the stand 140 and the first catalyst pack 110 move relative to each other in the horizontal direction, the abutment portion 145 and the flange portion 115 abut against each other. This restricts the relative movement between the stand 140 and the first catalyst pack 110 in the horizontal direction.

As shown in Figures 9 and 10, the locking portion 144 is provided at the bottom of the column portion 142. The locking portion 144 is fixed to the inner surface of the column portion 142. The locking portion 144 is a plate-like member that is approximately a right-angled triangle in a plan view. The locking portion 144 is located slightly above the lower end of the column portion 142. The locking portion 144 is placed on the upper surface of the rectangular frame portion 111 of the second catalyst pack 120. In this way, the stand 140 is locked to the second catalyst pack 120. In other words, the stand 140 is supported from below by the second catalyst pack 120.

10 , the lower end of the pillar portion 142 (more specifically, the portion below the locking portion 144) is fitted into the upper end of the second catalyst pack 120. Specifically, the upper end of the second catalyst pack 120 is fitted into the inside of the four pillar portions 142. That is, the distance between the inner surfaces of the pillar portions 142 adjacent to each other in the X-axis direction is set to be slightly longer than the length of the second catalyst pack 120 in the X-axis direction. Also, the distance between the inner surfaces of the pillar portions 142 adjacent to each other in the Y-axis direction is set to be slightly longer than the length of the second catalyst pack 120 in the Y-axis direction.
In this manner, the pillar portion 142 of the stand 140 and the second catalyst pack 120 are fitted together to restrict the horizontal relative movement between the stand 140 and the second catalyst pack 120. That is, the lower end of the pillar portion 142 serves as a restricting portion (hereinafter referred to as a "second restricting portion 147") that restricts the horizontal relative movement between the stand 140 and the second catalyst pack 120.

In this way, the first restricting portion 143 and the second restricting portion 147 restrict the horizontal movement of the stand 140. By configuring it in this way, even if an error occurs in the dimensions of the actually manufactured components of the stand 140, the first catalyst pack 110, or the second catalyst pack 120 compared to the designed dimensions, the error can be absorbed.

A plurality of steel frame sections 150 (two in this embodiment as an example) are arranged spaced apart in the vertical direction as shown in Fig. 2. The distance between the steel frame sections 150 is, for example, about 2 m. The distance between the steel frame sections 150 is determined based on the height of the space above a working floor 161 of a working structure 160, which will be described later. Each steel frame section 150 is fixed to the inner surface of the housing 47. Each steel frame section 150 is, for example, a long steel frame arranged in a lattice pattern.
Each steel frame section 150 supports a catalyst pack from below. Specifically, the second catalyst pack 120 is placed on the steel frame section 150 provided at the top. As described above, the stand 140 is placed on the second catalyst pack 120, and the first catalyst pack 110 is placed on the stand 140. That is, the loads of the first catalyst pack 110, the stand 140, and the second catalyst pack 120 act on the steel frame section 150 provided at the top. The steel frame section 150 provided at the bottom supports the third catalyst pack 130 from below. Only the load of the third catalyst pack 130 acts on the steel frame section 150 provided at the bottom.

As shown in FIG. 2 , the working structure 160 has two working floors 161 and a staircase 162 connecting the working floors 161 to each other.
The work floors 161 are disposed at a distance from each other in the vertical direction. The distance between the work floors 161 is, for example, about 2 m. This is to allow workers on the work floor 161 disposed below to pass safely on the work floor 161 and to set the height at which the catalyst packs 110, 120, and 130 can be loaded and unloaded. The height position of each work floor 161 is the same as the height position of the steel frame section 150.
The stairs 162 connect each of the work floors 161. That is, by ascending and descending the stairs 162, a worker moves between the upper work floor 161 and the lower work floor 161.

Next, a method for installing the first catalyst pack 110 and the second catalyst pack 120 will be described.
First, the second catalyst pack 120 is placed on the steel frame portion 150 arranged above. This results in the steel frame portion 150 supporting the second catalyst pack 120 from below.
Next, the stand 140 is placed on the second catalyst pack 120. In detail, the locking portion 144 of the stand 140 is placed on the upper surface of the rectangular frame portion 111 of the second catalyst pack 120. At this time, the stand 140 is placed so that the upper end portion of the rectangular frame portion 111 of the second catalyst pack fits into the lower end portion of the stand 140. This results in the second catalyst pack 120 supporting the stand 140 from below.
Next, the first catalyst pack 110 is placed on the stand 140. More specifically, the first catalyst pack 110 is placed on the upper surface of the beam portion 141 of the stand 140. This results in the stand 140 supporting the first catalyst pack 110 from below. Furthermore, when placing the first catalyst pack 110, it is placed so that the abutment portion 145 of the first restricting portion 143 and the flange portion 115 of the first catalyst pack 110 engage with each other.

Next, a method for performing maintenance work on the first catalyst pack 110 and the second catalyst pack 120 will be described.
A worker on the work floor 161 of the work structure enters the inside of the housing 47 through a manhole provided on the side of the housing 47. The manholes are provided individually at positions corresponding to each of the catalyst packs 110, 120, and 130, and the manhole 48 (see FIG. 3) is provided between the first catalyst pack 110 and the second catalyst pack 120 as an example. The worker who enters the inside of the housing 47 through a manhole (not shown) provided above the first catalyst pack 110 moves on the upper surface of the first catalyst pack 110 and performs maintenance of the first catalyst pack 110. In addition, the worker who enters the inside of the housing 47 through the manhole 48 shown in FIG. 3 similarly moves on the upper surface of the second catalyst pack 120 and performs maintenance of the second catalyst pack 120.

According to this embodiment, the following advantageous effects are obtained.
In this embodiment, a stand 140 is provided for supporting the first catalyst pack 110 on the second catalyst pack 120. As a result, the first catalyst pack 110 is supported on the housing 47 via the stand 140, the second catalyst pack 120, and the steel frame portion 150. Therefore, it is not necessary to provide a member that supports only the first catalyst pack 110 on the housing 47. Therefore, the structure can be simplified compared to a case in which two steel frame portions 150 are provided: a member that supports the first catalyst pack 110 on the housing 47 and a member that supports the second catalyst pack 120 on the housing 47.

In this embodiment, a work floor 161 for performing work on each catalyst pack (for example, work to install a catalyst pack or maintenance work on the catalyst pack) is provided outside the housing 47. In general, the height position of the work floor 161 is provided at a height position that is approximately the same as the height position of the steel frame part 150. Also, the work floor 161 is provided for each steel frame part 150. Therefore, when a plurality of steel frame parts 150 are provided, a plurality of work floors 161 are also provided. When a plurality of work floors 161 are provided, it is necessary to set the height so that workers on each work floor 161 can safely pass through, so that the interval between the work floors 161 needs to be relatively long (for example, about 2 m). As described above, the positions of the work floors 161 and the steel frame part 150 are approximately the same position, so if the interval between the work floors 161 is set to a relatively long interval, the interval between the steel frame parts 150 also becomes relatively long in correspondence with the interval between the work floors 161. For this reason, when a plurality of steel frame parts 150 are provided, it is necessary to provide a relatively long interval between the steel frame parts 150. Therefore, the greater the number of steel frame parts 150, the longer the vertical length of the denitration device 43.
On the other hand, in this embodiment, there is no need to provide a steel frame portion 150 that supports only the first catalyst pack 110 relative to the housing 47. This makes it possible to reduce the number of steel frame portions 150 compared to a case in which a steel frame portion 150 that supports the first catalyst pack 110 relative to the housing 47 and a steel frame portion 150 that supports the second catalyst pack 120 relative to the housing 47 are provided. This makes it possible to shorten the vertical length of the denitrification device 43. Furthermore, when a work floor 161 is provided corresponding to the steel frame portion 150, the number of work floors 161 can be reduced, thereby simplifying the structure.

When catalyst packs are directly stacked on top of each other without leaving any space between them, any misalignment of the catalyst packs may cause disturbances in the flow of the combustion gas at the stacked portion, causing ash mixed in the combustion gas to adhere and accumulate, resulting in blockage of the flow path. On the other hand, in this embodiment, the first catalyst pack 110 and the second catalyst pack 120 are spaced apart by a predetermined distance. This makes it difficult for the combustion gas to stagnate between the first catalyst pack 110 and the second catalyst pack 120.
In addition, if the distance between the first catalyst pack 110 and the second catalyst pack 120 is relatively short, the combustion gas is likely to stagnate between the first catalyst pack 110 and the second catalyst pack 120. On the other hand, in this embodiment, the first catalyst pack 110 and the second catalyst pack 120 are spaced apart by 500 mm or more. This makes it possible to suitably suppress the occurrence of stagnation of the combustion gas between the first catalyst pack 110 and the second catalyst pack 120. Therefore, the combustion gas that has passed through the first catalyst pack 110 can be more suitably guided to the second catalyst pack 120. Therefore, even if the combustion gas contains ash, it is possible to make it difficult for the ash to adhere to and accumulate on the second catalyst pack 120, so that clogging of the second catalyst pack 120 can be more suitably suppressed.

In addition, in this embodiment, a manhole 48 is provided between the first catalyst pack 110 and the second catalyst pack 120. This allows workers to enter the space between the first catalyst pack 110 and the second catalyst pack 120 through the manhole 48. Therefore, a worker who enters the space between the first catalyst pack 110 and the second catalyst pack 120 can perform work on the second catalyst pack 120.

In addition, in this embodiment, the beam 141 and the column 142 are rigidly joined. That is, the frame 140 has a rigid frame structure. In this way, since no reinforcing member (e.g., a brace, etc.) is provided between the beam 141 and the column 142, workers can enter the inside of the frame 140 through the gap between the beam 141 and the column 142. Furthermore, workers can easily move through the space between the first catalyst pack 110 and the second catalyst pack 120. Therefore, a worker who enters the space between the first catalyst pack 110 and the second catalyst pack 120 can perform work on each of the multiple second catalyst packs 120 arranged in the horizontal direction. Examples of work include maintenance work such as inspection and cleaning.

In addition, in this embodiment, a first restricting portion 143 and a second restricting portion 147 are provided to restrict horizontal relative movement with respect to the first catalyst pack 110 and the second catalyst pack 120. This makes it possible to restrict horizontal relative movement between the first catalyst pack 110 and the second catalyst pack 120 and the stand 140. Therefore, the first catalyst pack 110 can be stably supported by the second catalyst pack 120.

The present disclosure is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit and scope of the present disclosure.
For example, in the above-described embodiment, the boiler of the present disclosure is a coal-fired boiler, but the boiler may use solid fuels such as biomass fuel, PC (Petroleum Coke) fuel generated during oil refining, and oil residue. In addition, the fuel is not limited to solid fuels, and petroleum such as heavy oil, light oil, and heavy oil, and liquid fuels such as industrial wastewater can also be used, and further, gaseous fuels (natural gas, by-product gas, etc.) can also be used as fuel. Furthermore, the present disclosure can be applied to a multi-fuel boiler that uses a combination of these fuels.

For example, the steel frame portion 150 may be made into one, and the first catalyst pack 110, the second catalyst pack 120, and the third catalyst pack 130 may be supported by the steel frame portion 150. In this case, a stand 140 is also provided between the third catalyst pack 130 and the second catalyst pack 120. That is, the first catalyst pack 110, the second catalyst pack 120, and the third catalyst pack 130 are arranged so as to be triple-layered via the stand 140. In this way, the number of steel frame portions 150 can be further reduced, thereby further simplifying the structure and shortening the vertical length of the denitrification device 43. However, as in the present embodiment described above, when the steel frame 150 supported by the first catalyst pack 110 and the second catalyst pack 120 is separated from the third catalyst pack 130, it is easier to replace the catalyst packs (especially the third catalyst pack 130) compared to when the first catalyst pack 110, the second catalyst pack 120, and the third catalyst pack 130 are installed in triplicate.

The method of installing the denitration device, the frame, the boiler, and the denitration catalyst described in the above-described embodiment can be understood, for example, as follows.
A denitration device according to one embodiment of the present disclosure is a denitration device (43) that removes nitrogen oxides in combustion gas, and includes a first denitration catalyst (110) that is provided inside a housing (47) and through which combustion gas passes, a second denitration catalyst (120) that is provided inside the housing (47) below the first denitration catalyst (110) and through which combustion gas that has passed through the first denitration catalyst (110) passes, a stand (140) that is provided between the first denitration catalyst (110) and the second denitration catalyst (120) and supports the first denitration catalyst (110) on the second denitration catalyst (120), and a support member (150) that supports the second denitration catalyst (120) relative to the housing (47).

In the above configuration, a frame is provided for supporting the first denitration catalyst on the second denitration catalyst. As a result, the first denitration catalyst is supported on the housing via the frame, the second denitration catalyst, and the support member. Therefore, there is no need to provide a member for supporting the first denitration catalyst on the housing. Therefore, the structure can be simplified compared to a case in which two support members, a member for supporting the first denitration catalyst on the housing and a member for supporting the second denitration catalyst on the housing, are provided.
In addition, a floor (hereinafter referred to as a "work floor") for performing work on each denitration catalyst (for example, work to install a denitration catalyst or maintenance work on the denitration catalyst) may be provided outside the housing. In general, the height position of the work floor is provided at a height position that is approximately the same as the height position of the support member. In addition, a work floor is provided for each support member. For this reason, when a plurality of support members are provided, a plurality of work floors are also provided. When a plurality of work floors are provided, it is necessary to set the height so that workers on each work floor can safely pass through, so that the interval between the work floors needs to be relatively long (for example, about 2 m). As described above, since the positions of the work floor and the support member are set at approximately the same position, if the interval between the work floors is set to a relatively long interval, the interval between the support members will also be relatively long in correspondence with the interval between the work floors. For this reason, when a plurality of support members are provided, it is necessary to set a relatively long interval between the support members. Therefore, the greater the number of support members, the longer the vertical length of the denitration device.
On the other hand, in the above configuration, there is no need to provide a member for supporting the first denitration catalyst relative to the housing. This makes it possible to reduce the number of support members compared to a case in which two support members, a member for supporting the first denitration catalyst relative to the housing and a member for supporting the second denitration catalyst relative to the housing, are provided. This makes it possible to shorten the vertical length of the denitration device. Furthermore, when a work floor is provided corresponding to the support members, the number of work floors can be reduced, making it possible to simplify the structure.

In addition, in the denitration device according to one embodiment of the present disclosure, the first denitration catalyst (110) and the second denitration catalyst (120) are arranged to be separated by a predetermined distance.

In the above configuration, the first denitration catalyst and the second denitration catalyst are separated by a predetermined distance. This makes it difficult for the combustion gas to stagnate between the first denitration catalyst and the second denitration catalyst. Therefore, the combustion gas that has passed through the first denitration catalyst can be suitably guided to the second denitration catalyst. Therefore, even if the combustion gas contains ash, it is difficult for the ash to adhere to and accumulate on the second denitration catalyst, and clogging of the second denitration catalyst can be suppressed.

In addition, in one embodiment of the denitrification device of the present disclosure, the predetermined distance is 500 mm or more.

When the distance between the first and second denitration catalysts is relatively short, stagnation of the combustion gas is likely to occur between the first and second denitration catalysts. On the other hand, in the above configuration, the first and second denitration catalysts are separated by a distance of 500 mm or more. This makes it possible to effectively prevent stagnation of the combustion gas between the first and second denitration catalysts. Therefore, the combustion gas that has passed through the first denitration catalyst can be more effectively guided to the second denitration catalyst. Therefore, even if the combustion gas contains ash, it is possible to make it difficult for ash to adhere to and accumulate on the second denitration catalyst, thereby more effectively preventing clogging of the second denitration catalyst.

In addition, in the denitration device according to one embodiment of the present disclosure, the first denitration catalyst (110) and the second denitration catalyst (120) are arranged such that a manhole (48) formed in the housing (47) is located between the first denitration catalyst (110) and the second denitration catalyst (120).

In the above configuration, a manhole 48 is provided between the first denitration catalyst and the second denitration catalyst. This allows workers to enter the space between the first denitration catalyst and the second denitration catalyst through the manhole. Therefore, a worker who enters the space between the first denitration catalyst and the second denitration catalyst can perform work on the second denitration catalyst. Examples of work include maintenance work.

A boiler according to one aspect of the present disclosure is equipped with any of the denitrification devices described above.

The stand according to one embodiment of the present disclosure is provided between a first denitration catalyst (110) provided inside a housing (47) through which combustion gas passes, and a second denitration catalyst (120) provided inside the housing (47) below the first denitration catalyst (110) and supported by a support member (150) relative to the housing (47) through which combustion gas passes, and supports the first denitration catalyst (110) on the second denitration catalyst (120).

The stand according to one embodiment of the present disclosure includes a beam portion (141) extending horizontally and a column portion (142) extending vertically, and the beam portion (141) and the column portion (142) are rigidly joined.

In the above configuration, the beams and the column members are rigidly joined. That is, the frame has a rigid frame structure. In this way, since no reinforcing member (e.g., a brace, etc.) is provided between the beams and the column, workers can enter the inside of the frame through the gap between the beams and the column. Furthermore, workers can easily move through the space between the first denitration catalyst and the second denitration catalyst. Therefore, a worker who enters the space between the first denitration catalyst and the second denitration catalyst can perform work on each of the multiple second denitration catalysts arranged horizontally. Examples of work include maintenance work.

The stand according to one embodiment of the present disclosure also includes a restricting portion (143, 147) that restricts horizontal relative movement with respect to the first denitration catalyst (110) or the second denitration catalyst (120).

The above configuration includes a restricting portion that restricts horizontal relative movement with respect to the first denitration catalyst or the second denitration catalyst. This makes it possible to restrict horizontal relative movement between the first denitration catalyst or the second denitration catalyst and the stand. Therefore, the first denitration catalyst can be stably supported by the second denitration catalyst.

A method for installing a denitration catalyst according to one aspect of the present disclosure is a method for installing a denitration catalyst (110, 120) through which combustion gas passes, the denitration catalyst having a first denitration catalyst (110) and a second denitration catalyst (120) disposed below the first denitration catalyst (110), and including the steps of supporting the second denitration catalyst (120) on a support member (150) that supports the second denitration catalyst (120) relative to a housing (47), providing a stand (140) above the second denitration catalyst (120), and supporting the first denitration catalyst (110) on the second denitration catalyst (120) via the stand (140).

10: Coal-fired boiler 11: Furnace 12: Combustion device 13: Combustion gas passage 14: Flue 14a: Vertical section 21: Burner 26: Pulverized coal supply pipe 31: Crusher 36: Wind box 37: Air duct 41: Gas duct 42: Air heater 43: Denitrification device 44: Dust collector 46: Desulfurization device 47: Housing 48: Manhole 50: Chimney 101: Furnace wall 102: First superheater 103: Second superheater 104: Third superheater 105: First reheater 106: Second reheater 107: Coal economizer 110: First catalyst pack (first denitrification catalyst)
111: Rectangular frame portion 112: Denitrification catalyst (catalyst)
112a: outer frame portion 112b: partition wall 115: flange portion 116: catalyst receiving portion 117: catalyst pack structural member 120: second catalyst pack (second denitration catalyst)
130: third catalyst pack 140: stand 141: beam portion 142: column portion 143: first restricting portion 144: locking portion 145: contact portion 146: fixing portion 147: second restricting portion 150: steel frame portion (support member)
160: Work structure 161: Work floor 162: Stairs

Claims (8)

a frame provided between a first denitration catalyst provided inside a housing and through which combustion gas passes, and a second denitration catalyst provided inside the housing below the first denitration catalyst and supported by a support member relative to the housing and through which combustion gas passes, the frame supporting the first denitration catalyst on the second denitration catalyst,
A beam portion extending in a horizontal direction;
A column portion extending in the vertical direction;
Equipped with
The beam portion and the column portion are rigidly joined to each other. The stand according to claim 1 , further comprising a restricting portion that restricts relative movement in a horizontal direction with respect to the first denitration catalyst or the second denitration catalyst. A denitration device for removing nitrogen oxides from combustion gas,
The stand according to claim 1 or 2,
the first denitration catalyst provided inside the housing and through which combustion gas passes;
a second denitration catalyst provided below the first denitration catalyst within the housing, through which the combustion gas that has passed through the first denitration catalyst passes;
The support member supports the second denitration catalyst relative to the housing;
A denitrification device equipped with the above structure. 4. The denitration device according to claim 3, wherein the first denitration catalyst and the second denitration catalyst are arranged to be spaced apart from each other by a predetermined distance. 5. The denitration device according to claim 4, wherein the predetermined distance is 500 mm or more. A denitration device for removing nitrogen oxides from combustion gas,
a first denitration catalyst provided inside the housing and through which the combustion gas passes;
a second denitration catalyst provided inside the housing below the first denitration catalyst, through which the combustion gas that has passed through the first denitration catalyst passes;
a support provided between the first denitration catalyst and the second denitration catalyst for supporting the first denitration catalyst on the second denitration catalyst;
A support member that supports the second denitration catalyst relative to the housing;
Equipped with
The first denitration catalyst and the second denitration catalyst are arranged such that a manhole formed in the casing is located between the first denitration catalyst and the second denitration catalyst. A boiler equipped with the denitrification device according to any one of claims 3 to 6. A method for installing a denitration catalyst through which combustion gas passes, comprising the steps of:
The denitration catalyst includes a first denitration catalyst and a second denitration catalyst disposed below the first denitration catalyst,
a step of supporting the second denitration catalyst on a support member that supports the second denitration catalyst with respect to a housing;
Providing the frame according to claim 1 or 2 above the second denitration catalyst;
supporting the first denitration catalyst on the second denitration catalyst via the frame;
A method for installing a denitration catalyst comprising the steps of: