JP2019158267A - Auxiliary side wall bottom structure of coal burning boiler - Google Patents

Abstract

To provide an auxiliary side wall bottom structure of a coal burning boiler capable of quickly collecting ashes fallen to an auxiliary side wall bottom and discharging the ashes to the outside.SOLUTION: Openings 11 are formed at the auxiliary side wall bottom 8 of a coal burning boiler 1 composed of an aggregate of a plurality of heat transfer pipes 6, and hoppers 9a, 9b communicating with the openings 11 are mounted at a lower part of the auxiliary side wall bottom 8. The openings 11 are formed by partially bending the heat transfer pipes 6 constituting the auxiliary side wall bottom 8. Thus, the accumulation of ashes on the auxiliary side wall bottom 8 can be prevented without damaging the heat exchange efficiency of the coal burning boiler 1.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a sub-side wall bottom structure of a coal fired boiler.

  In a coal fired boiler, it is inevitable that ash and clinker (referred to collectively as “ash” in the present specification) on the heat transfer tube surface. For this reason, the coal-fired boiler is provided with a soot blower that ejects steam from a nozzle to remove ash adhering to the surface of the heat transfer tube.

  In the sub-side wall portion of the coal fired boiler, the ash adhering to the surface of the heat transfer tube suspended from the ceiling wall side is removed by a soot blower and dropped to the bottom of the sub-side wall. The bottom of the sub-side wall is an inclined surface that is inclined such that the upstream side (furnace side) of the combustion gas flow is low and the downstream side (rear heat transfer part side) is high. It descends along the slope and finally falls into the furnace. However, in recent years, low-grade coal with high ash content is often burned in a coal-fired boiler, and in this case, ash tends to accumulate on the bottom of the sub-side wall, which may cause a blockage of the combustion gas flow path. is there. Such a problem occurs not only in a boiler that uses a solid fuel with a large amount of ash and strong ash adhesion, but also in a coal-fired boiler that co-fires with other fuel types as well as coal.

  Conventionally, a coal fired boiler in which a hopper for extracting the ash deposited on the bottom of the sub-side wall is provided at the lower part of the bottom of the sub-side wall is known (see Patent Document 1).

JP 11-248104 A

  However, since Patent Document 1 does not disclose a specific sub-side wall bottom structure for collecting the ash deposited on the sub-side wall bottom in the hopper, it cannot be put into practical use as it is.

  The present invention has been made in order to solve the above-described problems of the prior art, and the sub-side wall of the coal-fired boiler that can quickly collect the ash dropped on the bottom of the sub-side wall into the hopper and discharge it to the outside. The object is to provide a bottom structure.

  In order to achieve the above object, a representative present invention includes an assembly of a plurality of heat transfer tubes, an opening formed in the assembly, and an upper end attached to a lower surface of the assembly and communicating with the opening. And the opening is formed by bending a heat transfer tube constituting the assembly.

  According to the present invention, the ash that has fallen to the bottom of the sub-side wall can be quickly collected in the hopper and discharged to the outside, so that ash accumulation on the bottom of the sub-side wall can be prevented. Problems, configurations, and effects other than those described above will become apparent from the description of the embodiments described below.

It is a lineblock diagram of a coal fired boiler concerning an embodiment. It is a principal part enlarged view of the coal fired boiler which concerns on embodiment. It is an enlarged plan view which shows the sub-side wall bottom part structure of the coal burning boiler which concerns on embodiment. It is an A direction arrow directional view of FIG. It is a perspective view which shows the shape and structure of the opening part provided in the sub-side wall bottom part of the coal burning boiler which concerns on embodiment. It is a bottom view which shows the shape and structure of the opening part provided in the sub side wall bottom part of the coal burning boiler which concerns on embodiment. It is a side view which shows the shape and structure of the opening part provided in the sub side wall bottom part of the coal burning boiler which concerns on embodiment.

  Hereinafter, the sub-side wall bottom part structure of the coal fired boiler which concerns on embodiment is demonstrated based on figures. In addition, embodiment described below shows a specific example at the time of implementing this invention, Comprising: The range of this invention is not restrict | limited to embodiment described below. For example, in the embodiment described below, a boiler using a solid fuel with a large amount of ash and strong ash adhesion will be described as an example, but the same applies not only to coal but also to a coal-fired boiler that co-fires with other fuel types. Can be applied to.

  Drawing 1 is a lineblock diagram of a coal fired boiler concerning an embodiment. As shown in FIG. 1, a coal fired boiler 1 of this example is provided with a furnace 2, a sub-side wall part 3 provided on the upper rear side of the furnace 2, and a rear side provided on the rear side of the sub-side wall part 3. And a rear heat transfer section 4. The furnace 2 includes a wind box 5 that blows air into the furnace 2, and a burner (not shown) that blows pulverized coal as fuel into the furnace 2 and burns it. . In addition, heat transfer tubes 6 functioning as a superheater, a reheater, a economizer, and the like are disposed inside the furnace 2, the sub-side wall part 3, and the rear heat transfer part 4, respectively.

  When air is introduced from the wind box 5 into the furnace 2 and fuel is injected from the burner and burned in the furnace 2, the high-temperature combustion gas generated in the furnace 2 is transferred to the furnace 2, the sub-side wall portion 3 and the rear transmission. It circulates in order of the heat part 4, and is finally discharged | emitted through the chimney which is not shown in figure. The high-temperature combustion gas exchanges heat with the fluid in the heat transfer tube 6 in the process of flowing through the furnace 2, the sub-side wall portion 3, and the rear heat transfer portion 4. Thereby, high temperature superheated steam is produced | generated.

  FIG. 2 is an enlarged view of a main part of the coal fired boiler according to the embodiment, and shows an enlarged configuration of the sub-side wall part 3. As shown in FIG. 2, a heat transfer tube 6 suspended from the ceiling wall side is disposed inside the sub-side wall portion 3, and two soot blowers 7 a for removing ash adhering to the heat transfer tube 6. , 7b. The first soot blower 7a is disposed on the upstream side in the flow direction A of the combustion gas in the sub-side wall portion 3 from the position where the heat transfer tube 6 is disposed, and the second soot blower 7b is disposed on the downstream side in the flow direction A of the combustion gas. Placed in. Thereby, the ash adhering to the upstream side and the downstream side of the heat transfer tube 6 in the flow direction A of the combustion gas can be removed using the soot blowers 7a and 7b.

  The sub-side wall bottom 8, which is the bottom of the sub-side wall 3, is inclined so that the upstream side (furnace side) in the combustion gas flow direction A in the sub-side wall 3 is low and the downstream side (rear heat transfer side) is high. It becomes an inclined surface. Fixed on the lower surface of the sub-side wall bottom 8 are hoppers 9a and 9b for collecting the ash removed from the heat transfer tube 6 by the soot blowers 7a and 7b and falling on the sub-side wall bottom 8 and discharging it to the outside. The hoppers 9a and 9b are respectively arranged on the upstream side and the downstream side in the combustion gas flow direction A in the sub-side wall portion 3 with respect to the arrangement position of the heat transfer tubes 6. Thereby, each ash removed from the heat transfer tube 6 by the soot blowers 7a and 7b can be efficiently collected in the hoppers 9a and 9b.

  FIG. 3 is an enlarged plan view showing a sub-side wall bottom structure of the coal fired boiler according to the embodiment. As shown in FIG. 3, the present invention is characterized in that the heat transfer tube 6 constituting the sub-side wall bottom 8 is curved to form the opening 11 communicating with the hoppers 9a and 9b. That is, the sub-side wall bottom 8 of the coal fired boiler 1 according to the embodiment is configured with an aggregate of a plurality of heat transfer tubes 6 connected to each other via the membrane bar 12. The opening 11 is related to the arrangement direction of the plurality of heat transfer tubes 6, and the heat transfer tube group 6 a on one side when viewed from the opening center O of the opening 11 and the heat transfer on the other side when viewed from the opening center O of the opening 11. The heat pipe 6b is formed by bending in a direction away from each other in a part of its length direction. The hoppers 9 a and 9 b are attached to the lower surface of the sub-side wall bottom 8 so that the upper ends communicate with the opening 11.

  4 is a view in the direction of arrow A in FIG. As shown in FIG. 4, a plurality of hoppers 9 a and 9 b are arranged at a predetermined interval in the width direction of the sub-side wall portion 3 (direction orthogonal to the paper surface of FIG. 2). Thereby, the ash can be collected by the hoppers 9a and 9b for the entire width direction of the sub-side wall portion 3. Note that the set interval between the adjacent hoppers 9a and 9b is determined in consideration of the workability of attaching the hoppers 9a and 9b to the sub-side wall bottom 8.

  Hereinafter, a specific configuration of the sub-side wall bottom 8 according to the embodiment will be described with reference to FIGS. FIG. 5 is a perspective view showing the shape and configuration of the opening provided at the bottom of the sub-side wall of the coal fired boiler according to the embodiment, FIG. 6 is a bottom view thereof, and FIG. 7 is a side view thereof. As shown in FIGS. 5 to 7, in the sub-side wall bottom 8 of this example, the first heat transfer tubes 6 a 1 and 6 b 1 are separated from each other in the plane of the sub-side wall bottom 8 when viewed from the opening center O of the opening 11. The third heat transfer tubes 6a3 and 6b3 as viewed from the opening center O of the opening 11 are bent so as to be disposed below the bending portions of the first heat transfer tubes 6a1 and 6b1. 11, the second heat transfer tubes 6 a 2 and 6 b 2 are bent so as to be disposed below the bending portions of the third heat transfer tubes 6 a 3 and 6 b 3. Further, in the sub-side wall bottom 8 of the present example, the fourth heat transfer tubes 6a4 and 6b4 when viewed from the opening center O of the opening 11 are the second heat transfer tubes 6a2 and 6b2 when viewed from the opening center O of the opening 11. The fifth heat transfer tubes 6a52 and 6b5 are curved so as to be disposed on the outer peripheral side of the curved portion 6b2, and the fifth heat transfer tubes 6a52 and 6b5 are located above the curved portions of the fourth heat transfer tubes 6a4 and 6b4. The sixth heat transfer tubes 6a6 and 6b6 are the outer peripheral sides of the curved portions of the fifth heat transfer tubes 6a5 and 6b5 when viewed from the opening center O of the opening 11, and It curves so that it may be arrange | positioned under the 2nd heat exchanger tube 6a7, 6b7.

  Thereby, since the curved part of each heat exchanger tube 6a1-6a6, 6b1-6b6 protrudes only under the sub-side wall bottom part 8 (refer FIG. 7), it almost prevents the flow of the combustion gas in the sub-side wall part 3. There is no. The curved structure of each of the heat transfer tubes 6a1 to 6a6 and 6b1 to 6b6 and the number of the heat transfer tubes to be bent are not limited to the above structure, and can be arbitrarily formed according to the size of the opening 11 or the like. .

  Since the sub-side wall bottom structure of the coal fired boiler according to the present invention is provided with the opening 11 at the sub-side wall bottom 8 and the hoppers 9a and 9b communicating with the opening 11 below the opening 11, the soot blower 7a, By driving 7b, the ash removed from the heat transfer tube 6 and falling onto the sub-side wall bottom 8 can be reliably taken into the hoppers 9a, 9b. Therefore, blockage of the combustion gas flow path due to ash accumulation on the sub-side wall bottom 8 can be prevented.

  Further, the sub-side wall bottom structure of the coal fired boiler according to the present invention forms the opening 11 by curving the heat transfer tube 6 constituting the sub-side wall bottom 8, so the quantity of the heat transfer tubes 6 constituting the sub-side wall portion 3 can be reduced. There is no decrease. Therefore, the heat exchange efficiency of the coal fired boiler 1 can be maintained.

  Note that the gist of the present invention is to form the opening 11 communicating with the hoppers 9a, 9b in the sub-side wall bottom 8, and the other can be implemented by making necessary design changes as appropriate. .

DESCRIPTION OF SYMBOLS 1 Coal-fired boiler 2 Furnace 3 Sub-side wall part 4 Rear heat transfer part 5 Wind box 6 Heat transfer tube 7a, 7b Soot blower 8 Sub-side wall bottom part 9a, 9b Hopper 11 Opening part 12 Membrane bar A Flow direction of combustion gas

Claims (5)

An assembly of a plurality of heat transfer tubes, an opening formed in the assembly, and a hopper attached to the lower surface of the assembly and having an upper end communicating with the opening,
The sub-side wall bottom structure of a coal fired boiler, wherein the opening is formed by bending the heat transfer tube constituting the assembly.   The said opening part is formed in multiple numbers, respectively in the flow direction of the combustion gas in the sub side wall part of a coal burning boiler, and the width direction of the said sub side wall part orthogonal to this. The bottom structure of the sub-side wall of a coal-fired boiler.   The said opening part formed in the flow direction of the said combustion gas is each arrange | positioned at the upstream and downstream of the said heat exchanger tube hung from the ceiling wall side of the said sub-side wall part, It is characterized by the above-mentioned. The sub-side wall bottom structure of the coal fired boiler according to 2.   The opening includes one or more heat transfer tubes disposed on one side as viewed from the opening center of the opening, and the opening center of the opening, with respect to the arrangement direction of the plurality of heat transfer tubes constituting the assembly. The one or more heat transfer tubes arranged on the other side when viewed from the side are bent in a direction away from each other in a part of the length direction, and the plurality of heat transfer tubes bent in the same direction are 2. The sub-side wall bottom structure of a coal fired boiler according to claim 1, wherein a part thereof is stacked in the thickness direction of the aggregate.   The sub-side wall bottom portion of the coal-fired boiler according to claim 1, wherein a part of the plurality of heat transfer tubes stacked in the thickness direction of the aggregate protrudes only on a lower side of the aggregate. Construction.

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