JP2019078500A - Boiler, steam temperature adjustment method and refractory material for boiler - Google Patents

Abstract

To provide a boiler capable of simply adjusting a steam temperature in simple configuration, and a refractory material for the boiler.SOLUTION: A boiler comprises: a flue forming an exhaust gas flow passage where exhaust gas discharged from a furnace flows; a heat exchanger provided in the exhaust gas flow passage, and configured to overheat steam; a bypass flue branched from an upstream side of the heat exchanger in the exhaust gas flow passage, and forming a bypass flow passage made confluent on a downstream side of the heat exchanger; and at least one refractory material laminated so as to close at least a part of a flow passage cross section in the bypass flow passage.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to boilers and boiler refractories.

  In general, it is very difficult to take measures against the case where the heat transfer area of the boiler is insufficient, so the heat transfer area is often given a margin at the time of design, which may cause the steam temperature to exceed the design temperature. It can happen. In particular, in biomass combustion boilers expected to increase in the future, the situation (moisture content etc.) of biomass used as fuel is very unstable and accurate prediction is difficult, so there is a high possibility of such a situation. For this reason, in order to adjust the temperature of the steam in the boiler, various studies have conventionally been made on a structure using a water spray, a structure capable of changing the heat transfer area between the exhaust gas and the heat exchanger, and the like.

  In patent documents 1 and 2, in order to adjust steam temperature, a partition plate is provided in a flue where exhaust gas flows so as to shield a part of a heat exchanger, and heat transfer is performed by changing the flow passage width of exhaust gas. A temperature control device with adjustable area is disclosed. Further, Patent Document 1 discloses that a heat transfer area is adjusted by providing a damper in contact with the partition plate and changing the flow passage width of the exhaust gas by adjusting the damper.

Japanese Utility Model Publication No. 61-204119 Japanese Utility Model Publication No. 60-160308

  However, even if the heat transfer area is limited in order to lower the steam temperature, the flow velocity of the gas is actually increased because the channel width is narrowed, and the heat transfer efficiency of the heat exchanger is increased. For this reason, the reduction effect of steam temperature may become limited. In addition, since the temperature of exhaust gas is usually a high temperature of 1000 ° C. or higher, it is actually difficult to install a movable device such as a damper under such an environment, and even if it is installed, the durability of the damper Problems can arise. Although it is conceivable to lower the exhaust gas temperature to the heat resistant temperature of the damper and adopt it, in that case, it is necessary to take measures such as installing an evaporation pipe in the exhaust gas flow path, which leads to an increase in cost.

  Therefore, in view of the above-described circumstances, an object of at least one embodiment of the present invention is to provide a boiler and boiler refractories capable of easily adjusting the steam temperature with a simple configuration.

(1) A boiler according to some embodiments of the present invention
A flue forming an exhaust gas flow path through which exhaust gas discharged from the furnace flows;
A heat exchanger provided in the exhaust gas flow path for superheating steam;
A bypass flue forming a bypass flow passage branched from the upstream side of the heat exchanger in the exhaust gas flow passage and joining the downstream side of the heat exchanger;
And at least one refractory stacked so as to close at least a part of the flow passage cross section in the bypass flow passage.

  According to the configuration of the above (1), when it is desired to raise the steam temperature, a large amount of exhaust gas can be passed through the heat exchanger by stacking the refractory and closing the flow passage cross section of the bypass flow passage. On the other hand, when it is desired to lower the steam temperature, the flow of exhaust gas toward the bypass flow channel is generated by removing the stacked refractory, and the flow rate of the exhaust gas passing through the heat exchanger can be reduced. As described above, the steam temperature can be easily adjusted by changing the degree of blockage of the flow passage cross section of the bypass flow passage and changing the flow rate of the exhaust gas passing through the heat exchanger by a simple method of stacking the refractories. You can do it.

(2) In some embodiments, in the configuration of (1) above,
The flue includes a plurality of tubes extending along the vertical direction,
The refractory is fitted between a pair of tubes adjacent in a direction intersecting the flow direction of the bypass flow passage at a branch point from the exhaust gas flow passage of the bypass flow passage.

  According to the configuration of the above (2), the refractory is fitted between the pair of tubes adjacent in the direction intersecting with the flow direction of the bypass flow passage at the branch point from the exhaust gas flow passage of the bypass flow passage. Be For this reason, the refractory can be stacked using the space formed between the tubes. Moreover, it can suppress that the piled-up refractory falls out by inserting a refractory between a pair of tubes.

(3) In some embodiments, in the configuration of (2) above,
The refractory has a recess in contact with the outer peripheral surface of each of the pair of tubes at both ends of the refractory.

  According to the configuration of the above (3), since the stacked refractory is in contact with the outer peripheral surface of the tube at the recess at the both end portions, the refractory becomes more difficult to drop out from between the tubes. This makes it possible to avoid damage to the boiler that can be caused by the falling of the refractory.

(4) In some embodiments, in the configuration of (3) above,
The refractory is a first portion and a second portion that are divided along the axial direction of the tube, and the first portion that abuts the tube on one side of the adjacent pair of tubes, and the adjacent portion Including a second portion that abuts the other of the pair of tubes
A first divided surface is formed in the first portion,
A second divided surface that contacts the first divided surface is formed at the second portion.

  According to the configuration of the above (4), the refractory is divided into the first portion and the second portion along the axial direction of the tube. The first portion abuts on one side of the adjacent pair of tubes, and the second portion is formed to abut on the other side of the adjacent pair of tubes. Therefore, when the refractory is stacked between a pair of adjacent tubes, for example, the second portion can be installed in contact with the other side of the tube after the first portion is installed in contact with one side of the tube. Therefore, the buildup and removal of the refractory between the pair of adjacent tubes is facilitated.

(5) In some embodiments, in the configuration of (4) above,
The first divided surface has a first tapered surface extending in a direction in which at least a portion of the first divided surface intersects with the axial direction of the tube.
The second divided surface is a second tapered surface extending in a direction in which at least a part of the second divided surface intersects with the axial direction of the tube, and the second divided surface abuts on the first tapered surface. It has a tapered surface.

  According to the configuration of (5), each of the first divided surface and the second divided surface is in contact with each other, the tapered surfaces (the first tapered surfaces extending in the direction intersecting at least a part with the axial direction of the tube) (A second tapered surface). For this reason, in the tapered surface, a pressing force that acts vertically downward from the first portion to the second portion or from the second portion to the first portion is generated. In addition, on the other hand, due to the pressing force, each recess of the refractory and the pair of tubes in contact with each recess are more closely attached, and the refractory can be firmly fixed between the adjacent pair of tubes. Thereby, the refractory can be stacked between the pair of tubes in a state in which the first portion and the second portion are in close contact with each other. Therefore, the rattle of the stacked refractory can be suppressed by the simple configuration.

(6) In some embodiments, in the configuration of (4) or (5) above,
The first divided surface has a convex portion protruding toward the second divided surface,
The second divided surface has a recess capable of receiving the protrusion.

  According to the configuration of the above (6), the first portion and the second portion can be installed so that the convex portion of the first divided surface is fitted into the recessed portion of the second divided surface. Therefore, it is possible to suppress displacement or separation between the first portion and the second portion, and to make it difficult to drop out the stacked refractory from between the tubes. Thereby, the damage to the boiler which may be caused by the falling of the refractory can be effectively avoided.

(7) In some embodiments, in any one of the configurations of (1) to (6) above,
The refractory comprises bricks.

  According to the structure of said (7), the cross-sectional area of a bypass flow path is easily adjustable only by piling up and removing the brick which is excellent in fire resistance, handling property, and cost.

(8) In some embodiments, in any one of the configurations (1) to (7),
Fuel containing biomass is burned in the furnace. That is, the boiler of the present embodiment is configured as a biomass combustion boiler that burns a fuel containing biomass (including biomass alone and a mixture of pulverized coal and biomass) in a furnace.

Biomass may differ greatly in its properties (such as moisture content) depending on the place of production, transport and storage conditions, and the like. Therefore, the biomass combustion boiler is likely to be in a situation where the steam temperature exceeds the design temperature.
According to the configuration of the above (8), in such a biomass combustion boiler, the exhaust gas passing through the heat exchanger is changed by changing the degree of blockage of the flow passage cross section of the bypass flow passage by a simple method of stacking refractories. The steam temperature can be easily adjusted by increasing or decreasing the flow rate of

(9) A steam temperature control method for a boiler according to some embodiments of the present invention,
It is a steam temperature control method in a boiler according to any one of the above (1) to (8),
Measuring the temperature of the steam superheated by the heat exchanger;
A difference calculating step of calculating a difference between a measured temperature of the steam measured in the temperature measuring step and a preset planned temperature;
Refractory number adjustment step of adjusting the number of the at least one refractory stacked so as to close the flow passage cross section of the bypass flow passage based on the difference calculated in the difference calculation step;
Equipped with

As described above, in the boiler according to some embodiments of the present invention, when it is desired to raise the steam temperature, the refractory is piled up and the exhaust gas is passed through the heat exchanger by blocking the flow passage cross section of the bypass flow passage. It can be done. On the other hand, when it is desired to lower the steam temperature, the flow of exhaust gas toward the bypass flow channel is generated by removing the stacked refractory, and the flow rate of the exhaust gas passing through the heat exchanger can be reduced.
Therefore, according to the configuration of the above (9), when the difference between the measured temperature and the planned temperature is larger than the predetermined value, for example, in the case of measured temperature> planned temperature, the stacked refractory is removed, and the measured temperature < In the case of the planned temperature, the measured temperature can be brought close to the planned temperature by stacking the refractory and closing the flow passage cross section of the bypass flow passage.

(10) A refractory for a boiler according to some embodiments of the present invention
A boiler refractory fitted between a pair of adjacent tubes, comprising:
The refractory has an (arc-like) recess that abuts on the outer peripheral surface of each of the pair of tubes at both ends of the refractory.
The refractory is a first portion and a second portion divided along the axial direction of the tube, the first portion contacting the tube on one side of the pair of tubes, and the adjacent pair And a second portion that abuts the other side of the tubes.

  According to the configuration of the above (10), since the stacked refractory is in contact with the outer peripheral surface of the tube at the recess at the both end portions, the refractory becomes more difficult to drop out from between the tubes. This makes it possible to avoid damage to the boiler that may be caused by the falling of the refractory. Also, the refractory is divided into a first portion and a second portion along the axial direction of the tube. The first portion abuts on one side of the adjacent pair of tubes, and the second portion is formed to abut on the other side of the adjacent pair of tubes. Therefore, when the refractory is stacked between a pair of adjacent tubes, for example, the second portion can be installed in contact with the other side of the tube after the first portion is installed in contact with one side of the tube. Therefore, the buildup and removal of the refractory between the pair of adjacent tubes is facilitated.

  According to at least one embodiment of the present invention, it is possible to provide a boiler and boiler refractories capable of easily adjusting the steam temperature with a simple configuration.

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic showing the whole structure of the boiler which concerns on some embodiment. FIG. 6 is a diagram illustrating the configuration of a branching unit and a merging unit according to some embodiments. It is the figure which looked at two types of cross sections in FIG. 2 from just above respectively. It is the figure which extracted and showed a part of waste gas communication part in FIG. It is the figure which looked at the CC 'cross section in FIG. 4 from just above. FIG. 7 is a perspective view of a refractory in accordance with some embodiments. It is a figure showing the modification of the refractory material which concerns on some embodiment. It is a flowchart for demonstrating the steam temperature method in the boiler which concerns on some embodiment. It is the map which showed the relationship between the blocking rate of a flow-path cross section, the difference of difference measurement temperature, and plan temperature based on some embodiment.

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

  First, with reference to FIG. 1, the whole structure of the boiler which concerns on some embodiment is demonstrated. FIG. 1 is a schematic diagram showing the overall configuration of a boiler 100 according to some embodiments.

  As shown in FIG. 1, a boiler 100 according to some embodiments includes a furnace wall 3 that internally forms a furnace 10 that is a combustion site, and a flue 35 that forms an exhaust gas flow path 30 downstream of the furnace 10. Equipped with The furnace 10 has a hollow shape and is provided along the vertical direction, and the furnace wall 3 constituting the furnace 10 is constituted by a heat transfer tube (not shown) extending along the vertical direction. Such a boiler 100 burns a fuel F such as coal supplied from the outside in the furnace 10 and passes the exhaust gas generated there through the heat exchanger 5 provided in the exhaust gas flow path 30, thereby a heat exchanger The temperature of the steam introduced to 5 can be raised.

  In some embodiments, the fuel F containing biomass is burned in the furnace 10. That is, the boiler 100 of the present embodiment is configured as a biomass combustion boiler in which the fuel F containing biomass (including biomass alone and the mixture of biomass and pulverized coal) is burned in the furnace 10.

  The steam drum 7 is connected to each heat transfer tube (not shown) of the furnace wall 3 and to the heat exchanger 5 via the steam line 9. The steam introduced into the heat exchanger 5 exchanges heat with the high temperature exhaust gas in the exhaust gas flow path 30 to raise the temperature, and then the water W is introduced in the overheat reduction device 13 via the steam line 11 Thus, the temperature is adjusted to a desired temperature. Thereafter, the steam S is supplied to an external turbine (not shown).

The boiler 100 according to some embodiments is, as shown in FIG. 1, a junction portion which is branched at a branch portion 31 on the upstream side of the heat exchanger 5 in the exhaust gas flow path 30 and located on the downstream side of the heat exchanger 5 A bypass flue 41 forming a bypass flow passage 40 joined at 33, and at least one refractory 50 stacked so as to close at least a part of the flow passage cross section in the bypass flow passage 40 are provided. The bypass flue 41 is formed of, for example, a duct connecting the branch portion 31 and the junction portion 33.
Here, stacking means that at least one refractory 50 is placed on an arbitrary installation surface of the flue 35 or the bypass flue 41 until a desired height is obtained (the refractory 50 is sequentially stacked over a plurality of steps) Mean that).

  According to the present embodiment, when it is desired to raise the steam temperature, the refractory 50 can be stacked to narrow the flow passage cross section of the bypass flow passage 40 so that the flow rate of the exhaust gas can be increased through the heat exchanger 5. The amount of heat exchange with can be increased. On the other hand, when it is desired to lower the steam temperature, the flow rate of the exhaust gas directed to the bypass flow passage 40 can be increased by removing the stacked refractory 50, and the flow rate of the exhaust gas passing through the heat exchanger 5 can be reduced. As described above, by changing the degree of blockage of the flow passage cross section of the bypass flow passage 40 by a simple method of only stacking and removing the refractory 50, the flow rate of the exhaust gas passing through the heat exchanger 5 can be increased or decreased. , You can easily adjust the steam temperature.

  In the embodiment illustrated in FIG. 1, the flow passage cross section of the bypass flow passage 40 is closed by stacking the refractory 50 in the branch portion 31, but in another embodiment, the refractory 50 is stacked in the merging portion 33 Alternatively, the cross section of the flow path may be closed.

  Furthermore, the portion where the refractory 50 is stacked may be between the branch portion 31 and the junction portion 33, and can be appropriately selected according to the structure of the bypass flue 41, the flow rate of the exhaust gas, and other conditions.

  Also, in some embodiments, the refractory 50 comprises bricks. Thereby, the cross-sectional area of the bypass flow path 40 can be easily adjusted only by piling up and removing the brick excellent in fire resistance, handling property, and cost.

  In addition, the refractory 50 is not limited to the above-described embodiment, and may be any object that retains its shape without being burned or melted even by the high temperature exhaust gas. For example, castable refractories of a monolithic refractor, plastic refractories and refractory mortars, or heat-resistant steel materials may be used.

  Here, the structures of the branch portion 31 and the merging portion 33 of the bypass flow passage 40 and the exhaust gas flow passage 30 according to some embodiments will be described with reference to FIGS. 2 and 3. FIG. 2 is a diagram illustrating the configurations of the branching unit 31 and the merging unit 33 according to some embodiments. FIG. 3 shows the two types of cross-sectional views in FIG. 2 as viewed from directly above.

  The flue 35 forming the exhaust gas flow path 30 is formed by connecting a plurality of tubes 21 extending along the vertical direction, which are arranged at predetermined intervals from one another, by seal fins 23. Therefore, the branch portion 31 and the merging portion 33 of the exhaust gas flow passage 30 and the bypass flow passage 40 are originally blocked by at least one tube 21 and the seal fin 23, and the exhaust gas flows into the bypass flow passage 40. There is no space.

Therefore, in some embodiments, as shown in FIG. 2, the exhaust gas can be formed by deforming a part (21 B, 21 D) of the plurality of tubes 21 (21 A to 21 E) in the branch part 31 and the junction part 33. An exhaust gas communication portion 25 for flowing into the bypass flow passage 40 is formed. In FIG. 2, a direction (depth direction in the drawing) perpendicular to the illustrated axial direction and axial direction is the flow direction of the bypass flow passage 40, and the exhaust gas flows from the near side to the far side in the drawing. In the example shown in FIG. 2, in one tube 21B of the adjacent tubes 21A and 21B, a portion in the axial direction of the tube 21B is bent downstream in the flow direction of the bypass flow passage 40. Further, in one tube 21D of the adjacent tubes 21C and 21D, a portion in the axial direction of the tube 21D is bent downstream in the flow direction of the bypass flow passage 40.
(A) of FIG. 3 shows a view of the AA 'cross section in FIG. 2 as viewed from directly above. In the cross section A-A ', the tubes 21B and 21D are not bent, so that the plurality of tubes 21 (21A to 21E) are connected by the seal fins 23. (B) of FIG. 3 is a cross-sectional view taken along the line B-B 'in FIG. In the cross section B-B ', the tubes 21B and 21D are bent toward the downstream side in the flow direction of the bypass flow passage 40. By removing the seal fin 23 at the bent portion, it is possible to open the portion which was originally blocked by the tube 21 and the seal fin 23 as in the A-A 'cross section as in the B-B' cross section, It is possible to form a space through which the exhaust gas passes (exhaust gas communication portion 25).

Further, focusing on the tubes 21A and 21B adjacent in the A-A 'cross section, in the B-B' cross section, the axis of one tube 21B is the downstream side of the axis of the other tube 21A in the flow direction of the bypass flow passage 40 To be positioned obliquely with respect to the flow direction of the bypass flow passage 40. As a result, it is possible to suppress a situation where the flow of the exhaust gas flowing into the bypass flow passage 40 is disturbed by the bent tube 21B.
As described above, in some embodiments, the tubes (21A, 21C, 21E) extending along the axial direction and a part of the axial direction are bent downstream in the flow direction of the bypass passage 40. The tubes (21B, 21D) are alternately arranged to form an exhaust gas communication portion 25 in the form of an iron grid.

  In addition, it is not necessary to necessarily form the waste gas communication part 25 of the branch part 31 and the junction part 33 by bending the tube 21 like said embodiment. For example, in another embodiment, the exhaust gas communication portion 25 may be formed by simply removing at least a part of the seal fins 23 in the axial direction between the tubes 21.

Here, in a region closed by the tube 21 and the seal fin 23 in the axial direction as in the A-A ′ cross section of FIG. 3A, the “adjacent pair of tubes” is, for example, the tube 21A and the tube 21B, a tube 21C, a tube 21D, and the like. In FIG. 3A, the tubes 21A, 21B, 21C, 21D, and 21E are arranged in this order, and a pair of adjacent tubes is connected by the seal fin 23.
On the other hand, in the region where the exhaust gas communication portion 25 is formed in the axial direction as in the B-B ′ cross section of FIG. 3B, “adjacent pair of tubes” means, for example, the tubes 21A and 21C, It should be noted that the term refers to the tube 21D and the tube 21E or the like.

FIG. 4 is a view extracting and showing a part of the exhaust gas communication portion 25 in FIG.
In some embodiments, as shown in (B) of FIG. 3 and FIG. 4, the refractory 50 is disposed at a branch point (branch portion 31, junction portion 33) from the exhaust gas flow path 30 of the bypass flow path 40 It is fitted between a pair of adjacent tubes 21 in a direction intersecting the flow direction of the bypass flow passage 40.
In the example shown in FIG. 3B, the refractory 50 is fitted between the pair of tubes 21 (21A and 21C and 21C and 21E) adjacent in the axial orthogonal direction in the region where the exhaust gas communication portion 25 is formed. It is done. However, the present embodiment is not limited to this, and the pair of tubes 21 into which the refractory 50 is fitted may be positioned so as to intersect the flow direction of the bypass flow passage 40. That is, for example, the refractory 50 may be fitted between the tubes 21B and 21C, between the tubes 21A and 21D, between the tubes 21D and 21E, or the like. Thus, the flow passage cross section of the bypass flow passage 40 is closed by the refractory 50 by fitting the refractory 50 between the pair of tubes 21 adjacent in the direction intersecting the flow direction of the bypass flow passage 40. I can do it.

  According to this embodiment, the refractory 50 can be stacked using the space formed between the tubes 21. Further, by fitting the refractory 50 between the pair of tubes 21, it is possible to prevent the stacked refractory 50 from falling off.

  In one embodiment, as shown in Drawing 4, receiving part 27 used as a pedestal of refractory 50 may be provided in a part used as an installation side in a place where refractorys 50 are piled up. That is, the refractory 50 may be placed on the receiving portion 27. In this case, the receiving portion 27 is supported by being welded, for example, on the upper end of the axially lower seal fin 23 forming the exhaust gas communication portion 25 (see FIG. 2).

  Hereinafter, some embodiments of the structure of the refractory 50 itself will be described with reference to FIGS. 5 to 7. FIG. 5 is a view of the CC ′ cross section in FIG. 4 as viewed from directly above. FIG. 6 is a perspective view of a refractory 50 according to some embodiments. FIG. 7 is a view showing a modified example of the refractory 50 according to some embodiments.

  In some embodiments, as shown in FIG. 5, the refractory 50 has a recess 54 that abuts on the outer peripheral surface of each of the pair of tubes 21 (21A, 21C) at both ends of the refractory 50. In the embodiment illustrated in FIG. 4, the recess 54 has an arc shape so as to abut on a part of the outer peripheral surface of each of the pair of tubes 21 (21 </ b> A, 21 </ b> C). Then, the refractory 50 is stacked so that the arc-shaped concave portion 54 abuts on a part of the outer peripheral surface of the tubes 21A and 21C, whereby the refractory 50 is fitted between the pair of adjacent tubes 21A and 21C. It is done.

  According to the present embodiment, since the stacked refractory 50 contacts the outer peripheral surface of the tube 21 at the concave portion 54 at the both end portions, the refractory 50 becomes more difficult to drop from between the tubes 21. Thereby, damage to the boiler 100 that may occur due to the falling of the refractory 50 can be avoided.

  In some embodiments, as shown in FIGS. 4 to 6, the refractory 50 is a first portion 51 and a second portion 52 that are divided along the axial direction of the tube 21, and a pair of adjacent ones It includes a first portion 51 that abuts the tube 21C on one side of the tubes, and a second portion 52 that abuts the tube 21A on the other side of the adjacent pair of tubes. A first divided surface 61 is formed in the first portion 51, and a second divided surface 62 in contact with the first divided surface 61 is formed in the second portion 52.

  According to the present embodiment, when the refractory 50 is stacked between the pair of adjacent tubes 21, for example, after the first portion 51 is installed to abut on the tube 21C on one side, the first portion 51 is installed. The second portion 52 can be placed in contact with the tube 21A on the other side from above. That is, if the refractory 50 is shaped so as to be fitted without gaps between the tubes 21, it may be difficult to install the refractory 50 between the tubes 21 if it can not be divided. Therefore, when the shape as in the present embodiment is adopted, the first portion 51 and the second portion 52 can be installed in order at the height position where the refractory 50 is to be stacked. Therefore, the stacking and removal of the refractory 50 between the pair of adjacent tubes 21 is facilitated.

  In some embodiments, as shown in FIGS. 4 and 6, the first dividing surface 51 extends in a direction in which at least a portion of the first dividing surface 51 intersects with the axial direction of the tube 21. The second divided surface 62 is a second tapered surface 72 which extends in a direction in which at least a part of the second divided surface 62 intersects with the axial direction of the tube 21, The first tapered surface 72 is in contact with the first tapered surface 71. In the embodiment illustrated in FIGS. 4 and 6, all of the first divided surface 61 and the second divided surface 62 have the first tapered surface 71 and the second tapered surface 72, but the present embodiment is not limited thereto. Alternatively, a part of the first divided surface 61 and the second divided surface 62 may have a tapered surface. In addition, a part of the first divided surface 61 and the second divided surface 62 may have a plurality of tapered surfaces.

  According to the present embodiment, in the first tapered surface 71 and the second tapered surface 72, a pressing force f that acts downward from the second portion 52 on the first portion 51 in the vertical direction is generated. Thereby, the refractory 50 can be stacked between the pair of tubes 21 in a state in which the first portion 51 and the second portion 52 are in close contact with each other. Also, on the other hand, a pair of tubes 21 (21A, 21C in FIG. 5) that are in contact with the respective recesses 54 of the refractory 54 and the respective recesses 54 by the pressing force f generated on the first tapered surface 71 and the second tapered surface 72. And the refractory 50 can be firmly fixed between the pair of adjacent tubes 21. Therefore, rattling of the stacked refractory 50 can be suppressed by a simple configuration.

  In some embodiments, as shown in FIGS. 5 and 6, the first parting surface 61 has a protrusion 56 projecting toward the second parting surface 62, and the second parting surface 62 is a protrusion It has a recess 58 that can receive 56. In the embodiment illustrated in FIGS. 5 and 6, the recess 58 and the protrusion 56 are formed continuously from the upper surface 64 to the lower surface 65 of the refractory 50 along the axial direction, but this embodiment is not limited thereto. The present invention is not limited to this, and the recess 58 and the protrusion 56 may be provided in a part in the axial direction, or the plurality of recesses 58 and the protrusions 56 may be provided on the first divided surface 61 and the second divided surface 62. May be In addition, the first divided surface 61 may have a recess 58, and the second divided surface 62 may have a protrusion.

  According to such an embodiment, the first portion 51 and the second portion 52 can be installed such that the convex portion 56 of the first divided surface 61 is fitted into the concave portion 58 of the second divided surface 62. Therefore, the shift and separation between the first portion 51 and the second portion 52 can be suppressed, and the stacked refractory 50 can be less likely to fall off between the tubes 21. Thereby, damage to the boiler 100 that may occur due to the falling of the refractory 50 can be effectively avoided.

In one embodiment, as shown in FIG. 7, the upper surface 64 and the lower surface 65 of the refractory 50 may be provided with a recess 68 and a protrusion 66. In the embodiment illustrated in FIG. 7, the convex portion 66 is provided on the upper surface 64 of the first portion 51 and the second portion, and the concave portion 68 is provided on the lower surface 65 of the first portion and the second portion. In this case, when the refractory 50 is stacked up and down, the convex portion 66 of the upper surface 64 engages with the recess 68 of the lower surface 65 of the refractory 50 stacked thereon. According to the present embodiment, even when the plurality of refractories 50 are stacked, the upper and lower refractories 50 are further fixed to each other, and therefore the dropping of the refractories 50 can be effectively suppressed. Although not shown, a recess 68 may be provided on the upper surface 64 and a protrusion 66 may be provided on the lower surface 65.
According to such an embodiment, the workability at the time of stacking the refractory 50 in a plurality of stages is improved, and the shift and separation between the refractory 50 stacked in the vertical direction are suppressed, and the stacked refractory 50 is It can be difficult to drop off from between 21.

FIG. 8 is a flow diagram for explaining a steam temperature method in a boiler 100 according to some embodiments.
Some embodiments of the present invention are the steam temperature control method in boiler 100 mentioned above, and as shown in Drawing 8, temperature measurement step S3 which measures the temperature of steam superheated by heat exchanger 5, and Based on the difference ΔT calculated in the difference calculation step S4 and the difference ΔT calculated in the difference calculation step S4, the bypass flow path is calculated in the difference measurement step S4 of calculating the difference ΔT between the actual measurement temperature Tm of the steam measured in the temperature measurement step S3 and the predetermined planned temperature Tp. Refractory number adjustment step S7 of adjusting the number of at least one refractory 50 stacked so as to close the flow path cross section of 40.

  In the embodiment shown in FIG. 8, first, the cross section of the flow passage is fully closed by the refractory 50 (S1), and the operation of the boiler 100 is started (S2). Then, in the above-described temperature measurement step S3, the temperature of the steam superheated by the heat exchanger 5 is measured, and in the above-described difference calculation step S4, the difference ΔT between the actual measurement temperature Tm and the planned temperature Tp Calculate). Then, after stopping the operation of the boiler 100 (S5), if the magnitude of the difference ΔT is equal to or more than the predetermined value Tth (Yes in S6), the flow passage cross section is closed in the above-described refractory number adjustment step S7. The number of at least one refractory 50 stacked in the On the other hand, when the magnitude (absolute value) of the difference ΔT is less than the predetermined value Tth (No in S6), the number adjustment of the refractory 50 is not performed (S8). Then, after S7 and S8 end, the operation of the boiler 100 is started again (S2). In the embodiment described above, the difference calculation step S4 may be performed after the operation of the boiler 100 is stopped.

As described above, in the boiler 100 according to some embodiments of the present invention, when it is desired to increase the steam temperature, the refractory 50 is stacked to block the flow passage cross section of the bypass flow passage 40, thereby exchanging much heat with exhaust gas. Can be passed through the vessel 5. On the other hand, when it is desired to lower the steam temperature, the flow of exhaust gas toward the bypass flow passage 40 is generated by removing the stacked refractory 50, and the flow rate of the exhaust gas passing through the heat exchanger 5 can be reduced.
Therefore, according to the above-described embodiment, when the difference between the actual measurement temperature Tm and the planned temperature Tp is larger than the predetermined value, for example, the accumulated refractory 50 is removed in the case of the actual measurement temperature Tm> the planned temperature Tp. In the case where the actual measurement temperature Tm <the design temperature Tp, the actual temperature Tm can be brought close to the design temperature Tp by stacking the refractory 50 and closing the cross section of the bypass flow channel 40.

  In some embodiments, the number of refractories 50 to be adjusted in accordance with the magnitude of the difference ΔT between the difference actual measurement temperature Tm and the planned temperature Tp is set in advance in the above-described number-of-refractories adjustment step S7. The number of refractory 50 may be adjusted based on the number set in advance. For example, if the magnitude of the difference ΔT is divided into a plurality of levels such as A level, B level and C level in descending order of magnitude, and the number of refractories 50 to be adjusted corresponding to each of the plurality of levels is set. Good.

  In some embodiments, map M (showing the relationship between the blockage ratio (%) of the flow passage cross section and the difference ΔT between the difference actual measurement temperature Tm and the planned temperature Tp in the above-described refractory quantity adjustment step S7 The number of refractories 50 to be adjusted may be determined based on FIG. If the relationship between the blocking rate (%) of the flow passage cross section and the refractory 50 to be stacked is known, the horizontal axis of the map M may be the number of the refractory 50 to be stacked. Such a map M may be created in advance before the start of operation of the boiler 100.

  According to such an embodiment, the number adjustment of the refractory 50 can be easily performed based on the calculated difference ΔT.

  In some embodiments, after the number of the refractory 50 is adjusted in the refractory number adjustment step S7 described above, the operation of the boiler 100 is started again, and the difference calculation step S4 described above If the calculated difference ΔT is still large (for example, in the case of ΔT ≧ Tth), the above-described map M may be corrected based on the result.

  According to such an embodiment, the accuracy in controlling the steam temperature based on the map M can be improved by correcting the map M based on the actual operation result.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to embodiment mentioned above, The form which added deformation | transformation to embodiment mentioned above, and the form which combined these forms suitably are also included. For example, although each embodiment was explained based on a circulation type boiler which has steam drum 7 (refer to Drawing 1), and circulates boiler water via steam lines 9 and 11, the present invention is not limited to this. . For example, it can be applied to a once-through boiler or the like which does not have the steam drum 7 and generates steam without circulating boiler water.

In the present specification, a representation representing a relative or absolute arrangement such as "in a direction", "along a direction", "parallel", "orthogonal", "center", "concentric" or "coaxial" Not only represents such an arrangement strictly, but also represents a state of relative displacement with an tolerance or an angle or distance that can obtain the same function.
For example, expressions that indicate that things such as "identical", "equal" and "homogeneous" are equal states not only represent strictly equal states, but also have tolerances or differences with which the same function can be obtained. It also represents the existing state.
Furthermore, in the present specification, expressions representing shapes such as a square shape and a cylindrical shape not only indicate shapes such as a square shape and a cylindrical shape in a geometrically strict sense, but also within the range where the same effect can be obtained. Also, the shape including the uneven portion, the chamfered portion, and the like shall be indicated.
Moreover, in the present specification, the expressions “comprising”, “including” or “having” one component are not exclusive expressions excluding the presence of other components.

Reference Signs List 3 furnace wall 5 heat exchanger 7 steam drum 9, 11 steam line 10 furnace 13 overheat reducer 21 tube 23 seal fin 25 exhaust gas communication part 27 receiving part 30 exhaust gas flow path 31 branch part 33 joining part 35 flue 40 bypass flow path 41 bypass flue 50 refractory 51 first portion 52 second portion 54 concave portion 56 convex portion 58 concave portion 61 first divided surface 62 second divided surface 64 upper surface 65 lower surface 71 first tapered surface 72 second tapered surface 100 boiler F fuel W water S steam G exhaust gas f pushing force M map

Claims (10)

A flue forming an exhaust gas flow path through which exhaust gas discharged from the furnace flows;
A heat exchanger provided in the exhaust gas flow path for superheating steam;
A bypass flue forming a bypass flow passage branched from the upstream side of the heat exchanger in the exhaust gas flow passage and joining the downstream side of the heat exchanger;
A boiler comprising: at least one refractory stacked so as to close at least a part of a flow passage cross section in the bypass flow passage. The flue includes a plurality of tubes extending along the vertical direction,
The refractory according to claim 1, wherein the refractory is fitted between a pair of adjacent tubes in a direction intersecting the flow direction of the bypass flow passage at a branch point from the exhaust gas flow passage of the bypass flow passage. boiler.   The boiler according to claim 2, wherein the refractory has a recess that abuts on the outer peripheral surface of each of the pair of tubes at both ends of the refractory. The refractory is a first portion and a second portion that are divided along the axial direction of the tube, and the first portion that abuts the tube on one side of the adjacent pair of tubes, and the adjacent portion Including a second portion that abuts the other of the pair of tubes
A first divided surface is formed in the first portion,
The boiler according to claim 3, wherein a second divided surface that contacts the first divided surface is formed in the second portion. The first divided surface has a first tapered surface extending in a direction in which at least a portion of the first divided surface intersects with the axial direction of the tube.
The second divided surface is a second tapered surface extending in a direction in which at least a part of the second divided surface intersects with the axial direction of the tube, and the second divided surface abuts on the first tapered surface. The boiler according to claim 4 having a tapered surface. The first divided surface has a convex portion protruding toward the second divided surface,
The boiler according to claim 4 or 5, wherein the second divided surface has a recess capable of receiving the protrusion.   The boiler according to any one of claims 1 to 6, wherein the refractory comprises bricks.   The boiler according to any one of claims 1 to 7, wherein fuel containing biomass is burned in the furnace. The steam temperature control method in a boiler according to any one of claims 1 to 8, wherein
Measuring the temperature of the steam superheated by the heat exchanger;
A difference calculating step of calculating a difference between a measured temperature of the steam measured in the temperature measuring step and a preset planned temperature;
Refractory number adjustment step of adjusting the number of the at least one refractory stacked so as to close the flow passage cross section of the bypass flow passage based on the difference calculated in the difference calculation step;
Steam temperature control method comprising: A boiler refractory fitted between a pair of adjacent tubes, comprising:
The refractory has a recess in contact with the outer peripheral surface of each of the pair of tubes at both ends of the refractory.
The refractory is a first portion and a second portion divided along the axial direction of the tube, the first portion contacting the tube on one side of the pair of tubes, and the adjacent pair A refractory for a boiler, comprising: a second portion that abuts the tube on the other side of the tubes.

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