JP6453323B2 - Replacement method of boiler and its heat transfer tube - Google Patents

Description

  The present invention relates to a boiler and a method for replacing the heat transfer tube, and more particularly, to a boiler having a radiation chamber and a flue having at least a part of a wall surface formed of a membrane wall and a method for replacing the heat transfer tube.

  Conventionally, a flow path for high-temperature gas generated in a combustion chamber is formed by a membrane wall to form a radiation chamber and a flue, and a superheater is installed in the radiation chamber and / or the flue. A boiler that generates superheated steam by heating the steam flowing inside with a high-temperature gas is known (Patent Document 1). The generated superheated steam can be used for power generation, for example, as a driving force of a turbine.

  FIG. 9 shows an outline of the overall configuration of a conventional boiler 80, and hot gas from the combustion chamber 81 flows into the second radiation chamber 83 through the first radiation chamber 82 and further into the third flue 84. Inflow. A plurality of superheaters 86 are installed in the third flue 84 formed by the membrane wall 85.

  As shown in FIG. 10, the heat transfer tube 87 of the superheater 86 includes a heat transfer tube main body portion 87 </ b> A disposed inside the third flue 84, an inlet tube portion 87 </ b> B and an outlet that are spaced apart in the vertical direction. It has a tube portion 87C and has a panel-like shape as a whole (hereinafter referred to as “heat transfer tube panel”). As shown in FIG. 10A, the superheater 86 is configured by arranging a large number of heat transfer tube panels 88 in the horizontal direction.

  As shown in FIGS. 10A and 10B, the inlet tube portion 87B and the outlet tube portion 87C of the heat transfer tube 87 constituting the heat transfer tube panel 88 pass through the membrane wall 85, and the third flue It is connected to the header 89 outside 84. The portion of the heat transfer tube 87 where the inlet tube portion 87B and the outlet tube portion 87C penetrate the membrane wall 85 is kept airtight by the wall box 90 and the refractory material therein.

  Some fuels that are put into the combustion chamber 81 of the boiler 80 shown in FIG. 9 generate a highly corrosive component at the time of combustion, such as waste fuel. The heat transfer tube 87 may be thinned by contacting the heat transfer tube 87 of the superheater 86. For this reason, before the thickness reduction of the heat transfer tube 87 due to corrosion exceeds the allowable limit, the corroded heat transfer tube 87 is taken out from the third flue 84 and replaced with a new heat transfer tube.

  When removing the corroded heat transfer tube 87 in the conventional boiler 80 shown in FIG. Cut at a point 91. Further, the wall box 90 and the refractory material inside thereof are removed.

  Further, a slit-like opening 92 for individually taking out the heat transfer tube panel 88 is formed in the membrane wall 85 opposite to the membrane wall 85 through which the inlet tube portion 87B and the outlet tube portion 87C of the heat transfer tube 87 pass. FIG. 11 shows a membrane wall 85 in which slit-like openings 92 are formed. In order to form one slit-like opening 92, a plurality of water tubes 85A of the membrane wall 85 and a wall material 85B between them are cut off. Is done.

  The heat transfer tube panel 88 separated from the header 89 is moved to the left side in the drawings in FIGS. 10A and 10B, and the inlet tube portion 87B and the outlet tube portion 87C that have penetrated the right membrane wall 85 in the drawing. Is drawn from the membrane wall 85 to the third flue 84 side.

  The heat transfer tube panel 88 into which the inlet tube portion 87B and the outlet tube portion 87C are drawn is moved upward or downward in FIG. 10A by the worker in the third flue 84, and the membrane wall 85 Are transferred to the position of the nearest slit-shaped opening 92 formed.

  From this state, the heat transfer tube panel 88 is moved to the left in FIG. 10A, and the heat transfer tube panel 88 is moved through the slit-shaped opening 92 of the membrane wall 85 as shown in FIG. Take out from the third flue 84 to the second radiation chamber 83 side.

  After the heat transfer tube panel 88 including the corroded heat transfer tube 87 is taken out by the above-described operation, a new heat transfer tube panel 88 for replacement is disposed at a predetermined position by a procedure reverse to the above-described operation.

  The inlet pipe portion 87B and the outlet pipe portion 87C of the new heat transfer tube panel 88 are connected to the inlet pipe portion 87B and the outlet pipe portion 87C left in the header 89 by welding. A new wall box 90 and a refractory material inside thereof are installed at a location where the inlet pipe portion 87B and the outlet pipe portion 87C of the new heat transfer tube panel 88 penetrate the membrane wall 85.

  The slit-shaped opening 92 formed in the membrane wall 85 for carrying out and carrying in the heat transfer tube panel 88 is hermetically sealed by welding a newly manufactured membrane wall piece.

JP 2013-53829 A

  As described above, in a conventional boiler, in order to replace a corroded heat transfer tube with a new heat transfer tube, cutting and welding operations of the inlet tube portion and the outlet tube portion of each heat transfer tube, the fire resistance of the wall box and the inside thereof are performed. It requires a lot of complicated work such as material removal and installation work, slit-like opening and sealing work in the membrane wall, and heat transfer tube moving work in the radiant chamber or flue. Needed.

  In particular, performing the welding operation of the inlet pipe portion and the outlet pipe portion of the heat transfer pipe in a limited and narrow space and in many places has resulted in a prolonged construction period. In addition, the sealing work of the slit-like opening of the membrane wall requires the production of a new membrane wall piece and the welding work thereof, which is a heavy burden of work and prolongs the construction period. .

  The present invention has been made in view of the above-described problems of the prior art, and can reduce the load of replacing a corroded heat transfer tube and shorten the operation time of the boiler and its heat transfer tube. It is intended to provide a replacement method.

  In order to solve the above-mentioned problem, the present invention according to the first aspect includes a boiler having a casing in which at least a part of a wall surface is formed of a membrane wall, a heat transfer tube panel disposed inside the casing, and the heat transfer tube. A collecting pipe connected to a heat pipe panel and disposed outside the casing, and a membrane wall opening formed in the membrane wall so that the heat transfer pipe panel can be taken in and out of the casing. It is characterized by that.

  The present invention according to a second aspect is characterized in that, in the present invention according to the first aspect, further comprising a sealing member detachably attached to the membrane wall for sealing the membrane wall opening. To do.

  The present invention according to a third aspect is the present invention according to the first or second aspect, wherein the plurality of heat transfer tube panels connected to the collecting pipe and the plurality of heat transfer tube panels are respectively formed. And a plurality of the membrane wall openings.

  The present invention according to a fourth aspect is the present invention according to the third aspect, comprising a sealing member that is detachably attached to the membrane wall in order to seal the membrane wall opening, The plurality of membrane wall openings are formed as an integral member for sealing the whole.

  The present invention according to a fifth aspect is characterized in that in the present invention according to the second or fourth aspect, the sealing member is fixed to the membrane wall by a detachable fastener.

  The present invention according to a sixth aspect is the heat transfer tube module according to any one of the first to fifth aspects, comprising a plurality of the heat transfer tube panels and the collecting tube to which the plurality of heat transfer tube panels are connected. It is characterized by having multiple.

  The present invention according to a seventh aspect is characterized in that, in the present invention according to the sixth aspect, each of the plurality of collecting pipes is connected to a common pipe via each connecting pipe.

  The present invention according to an eighth aspect is characterized in that, in the present invention according to the seventh aspect, the common pipe is arranged at a position where a space for drawing out the heat transfer tube panel can be secured.

  The present invention according to a ninth aspect is a method for replacing a heat transfer tube in a boiler according to any one of the first to eighth aspects, wherein the collecting pipe to which the heat transfer tube panel is connected, and A step of releasing the fixed state of the heat transfer tube panel with respect to the membrane wall, and a step of moving the heat transfer tube panel in the casing together with the collecting pipe and pulling it out of the casing. .

  The tenth aspect of the present invention is a method for replacing a heat transfer tube in the boiler of the present invention according to the sixth aspect, the step of separating the collecting tube to which the heat transfer tube panel is connected, and the heat transfer tube to the membrane wall. A step of releasing the fixed state of the panel, and a step of moving the heat transfer tube panel in the casing together with the collecting tube and pulling it out of the casing, wherein the heat transfer tube panel is provided for each heat transfer tube module. It is drawn out of the casing.

  The present invention according to an eleventh aspect is a method for replacing a heat transfer tube of a boiler according to the eighth aspect of the present invention, comprising the step of disconnecting a collecting tube to which the heat transfer tube panel is connected, and the heat transfer tube to the membrane wall. A step of releasing the fixed state of the panel, and a step of moving the heat transfer tube panel in the casing together with the collecting tube and pulling it out of the casing, the heat transfer tube passing between a pair of the common pipes The panel is pulled out.

  ADVANTAGE OF THE INVENTION According to this invention, the replacement method of the heat exchanger tube which reduced the load of the replacement | exchange operation | work of the corroded heat exchanger tube, and can aim at shortening of work time can be provided.

The side view which showed the outline of the whole structure of the boiler by one Embodiment of this invention. The horizontal sectional view which expanded and showed the part of the superheater and header arrange | positioned in the 3rd flue of the boiler shown in FIG. The side view which expanded and showed the part of the superheater and header arrange | positioned in the 3rd flue of the boiler shown in FIG. IV-IV arrow line view of FIG. FIG. 5 is a view taken along arrow V-V in FIG. 3. The perspective view which expanded and showed the part of the heat exchanger tube unit of the boiler shown in FIG. 1 with the header etc. FIG. The perspective view for demonstrating the replacement method of the heat exchanger tube in the boiler shown in FIG. The side view for demonstrating the replacement method of the heat exchanger tube in the boiler shown in FIG. The side view which showed the outline of the whole structure of the conventional boiler. It is the figure which expanded and showed the part of the superheater and header arrange | positioned in the 3rd flue of the conventional boiler shown in FIG. 9, (a) is a horizontal sectional view, (b) is the side surface of (a). (C) is the side view which showed the removed heat exchanger tube. XX arrow line view of FIG.10 (b).

  Hereinafter, a boiler and a heat transfer tube replacement method according to an embodiment of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, in the boiler 10 according to the present embodiment, the hot gas from the combustion chamber 11 flows into the second radiation chamber 13 through the first radiation chamber 12, and further, the third flue (casing) 14. It is comprised so that it may flow into.

  In the 3rd flue 14 comprised with the membrane wall 15, the 1st superheater 16, the 2nd superheater 17, and the 3rd superheater 18 are installed toward the downward direction from the upper direction. Hot gas flows through the third flue 14 from below to above. On the other hand, the steam heated by the high-temperature gas flows from the first superheater 16 to the second superheater 17 and from the second superheater 17 to the third superheater 18 from top to bottom. The superheated steam generated by the first to third superheaters 16, 17, 18 can be used, for example, as a driving force of a turbine to generate electric power.

  Among the first to third superheaters 16, 17, 18, particularly the third superheater 18 and the second superheater 17 have severe temperature conditions, and the progress of thinning due to corrosion is fast. It is necessary to perform replacement work relatively frequently.

  In the boiler 10 according to the present embodiment, as shown in FIG. 2, a header (collecting pipe) 19 connected to the third superheater 18 is divided into first to sixth headers 19. Six (or five) heat transfer tube panels 20 are connected to each of the sixth headers 19.

  As shown in FIGS. 2 and 3, the heat transfer tube 21 of the heat transfer tube panel 20 includes a heat transfer tube main body portion 21 </ b> A disposed inside the third flue 14, and an inlet extending through the membrane wall 15. A pipe part 21B and an outlet pipe part 21C are provided.

  As shown in FIGS. 4 and 5, the inlet tube portion 21 </ b> B and the outlet tube portion 21 </ b> C of the heat transfer tube 21 of the heat transfer tube panel 20 penetrate the membrane wall 15 between adjacent water tubes 15 </ b> A of the membrane wall 15. Yes.

  When the pitch of the water tubes 15A of the membrane wall 15 and the pitch of the heat transfer tubes 21 are different, the water tubes 15A and / or the heat transfer tubes 21 of the membrane wall 15 are appropriately curved as shown in FIGS. Thus, interference between the water pipe 15A and the heat transfer pipe 21 is avoided.

  As shown in FIG. 4, in the region through which the inlet pipe portion 21 </ b> B and the outlet pipe portion 21 </ b> C of the heat transfer pipe 21 penetrate, the membrane wall 15 has a penetration portion of each inlet pipe portion 21 </ b> B and a penetration portion of each outlet pipe portion 21 </ b> C. Each membrane wall opening 22 formed continuously in the extending direction of the water pipe 15A is formed.

  As shown in FIG. 3, the membrane wall opening 22 formed in the membrane wall 15 has first to sixth sealing flanges (sealing) provided corresponding to the first to sixth headers 19, respectively. Sealing member 23). The inlet tube portion 21 </ b> B and the outlet tube portion 21 </ b> C of the heat transfer tube 21 pass through the sealing flange 23, and the sealing member 24 ensures airtightness of those through portions.

  The sealing flange 23 is fixed to the membrane wall 15 by bolts (fasteners) 25, and the sealing flange 23 can be attached to and detached from the membrane wall 15 by attaching and detaching the bolts 25. As shown in FIG. 3, in the boiler 10 according to the present embodiment, the sealing flange portion also serves as a wall box in the conventional boiler.

  As shown in FIG. 6, each of the first to sixth headers 19, the six heat transfer tube panels 20 connected to each header 19, and each sealing flange 23 constitute each heat transfer tube module 26. ing. The boiler 10 according to this embodiment includes a total of six heat transfer tube modules 26.

  As shown in FIG. 3, the inlet pipe portion 21A and the outlet pipe portion 21B of the heat transfer pipe 21 extending outward from the membrane wall 15 are connected to the header 19, and the first to sixth headers 19 are respectively connected to the connecting pipes. 27 is connected to the upper and lower common pipes 28. The upper and lower common pipes 28 are arranged at positions where a space for drawing out the heat transfer tube panel 20 can be secured.

  Next, a method for removing the corroded heat transfer tube 21 in the boiler 10 according to the present embodiment will be described.

  Of the first to sixth headers 19, the connecting tube 27 of the header 19 belonging to the heat transfer tube module 26 including the corroded heat transfer tube 21 is cut at the cutting position 29 shown in FIG. 3 (header 19 separation step). . Next, the bolt 25 that fixes the sealing flange 23 to the membrane wall 15 is removed, and the fixing state of the sealing flange 23 to the membrane wall 15 is released (step of releasing the sealing flange 23).

  Next, the entire heat transfer tube module 26 is moved as shown in FIGS. 7 and 8, and the heat transfer tube 21 in the third flue 14 is drawn out to the outside through the membrane wall opening 22 (heat transfer tube 21 Drawing process). At this time, as shown in FIG. 3, the common pipe 28 is shifted in advance up and down, so that the heat transfer tube module 26 can be drawn out between the upper and lower common pipes 28 as shown in FIG. .

  When a new heat transfer tube module 26 is installed instead of the removed heat transfer tube module 26, each heat transfer tube panel 20 of the new heat transfer tube module 26 is attached to the membrane wall 15 contrary to the above-described removal process. It inserts in the inside of the 3rd flue 14 through each membrane wall opening part 22 formed between adjacent water pipes 15A.

  Next, the sealing flange 23 of the new heat transfer tube module 26 is fixed to the membrane wall 15 with bolts 25. Further, the connecting pipe 27 of the header 19 of the new heat transfer pipe module 26 is connected to the connecting pipe 27 left on the common pipe 28 side by welding when the corroded heat transfer pipe module 26 is removed.

  As described above, according to the method for replacing the boiler 10 and its heat transfer tube 21 according to the present embodiment, when removing the corroded heat transfer tube 21 from the boiler 10, the connecting tube connecting the header 19 and the common pipe 28. 27, and only the bolt 25 of the sealing flange 23 is removed. When the new heat transfer tube 21 is attached to the boiler 10, the connecting tube 27 is welded and the sealing flange 23 is fixed with the bolt 25. (In other words, remanufacturing of the membrane wall that is required in the past and its welding work are no longer necessary, so there is no need for on-site welding of the heat transfer tube), which greatly simplifies the work process compared to conventional boilers. Therefore, the construction period required for the heat transfer tube replacement work can be shortened.

  In particular, in the present embodiment, it is possible to greatly simplify the field work of a very time-consuming part such as cutting of a pipe and its recovery (welding), which is extremely advantageous in reducing the work load and shortening the construction period. is there.

  Moreover, in the boiler 10 in this embodiment, since the header 19 was divided | segmented and each heat exchanger tube module 26 was comprised for every divided header 19, replacement | exchange of the heat exchanger tube 21 is carried out for each module unit. Can be done. Thereby, compared with the case where the header 19 is not divided | segmented, the dimension and weight of a conveyance target object (heat-transfer tube module 26) become small, and workability | operativity can be improved.

  In addition, the removed heat transfer tube module 26 is transported from the site to an inspection / repair factory, and if it is determined that it can be reused as a result of the inspection, the corroded portion is repaired and reused when the heat transfer tube is replaced next time. be able to.

  Further, if the spare heat transfer tube module 26 is prepared in advance and the heat transfer tube module 26 including the corroded heat transfer tube 21 is replaced with the spare heat transfer tube module 26, the work period can be further shortened. Can be planned.

  In the present embodiment, the header 19 is divided into six to constitute the six heat transfer tube modules 26 as described above. However, in the boiler according to the present invention, division of the header is not necessarily essential. For example, the entire header may be removed together with all the heat transfer tube panels connected thereto without dividing the header.

  In the present embodiment, the plurality of membrane wall openings 22 are sealed with a single sealing flange 23. For example, each of the plurality of membrane wall openings 22 is sealed with each sealing flange. It can also be individually sealed.

  In addition, as an application object of this invention, it is not limited to the coal burning boiler and the boiler as described in the said embodiment, In short, the boiler provided with the boiler wall which has a membrane wall may be an application object. For example, a boiler using exhaust gas without having a combustion furnace may be used.

DESCRIPTION OF SYMBOLS 10 Boiler 11 Combustion chamber 12 1st radiation chamber 13 2nd radiation chamber 14 3rd flue (casing)
DESCRIPTION OF SYMBOLS 15 Membrane wall 15A Membrane wall water pipe 16 1st superheater 17 2nd superheater 18 3rd superheater 19 Header (collection pipe)
20 Heat Transfer Tube Panel 21 Heat Transfer Tube of Superheater 21A Heat Transfer Tube Body 21B Heat Transfer Tube Inlet Tube 21C Heat Transfer Tube Outlet Tube 22 Membrane Wall Opening 23 Sealing Flange (Sealing Member)
24 Seal member 25 Bolt (fastener)
26 Heat Transfer Tube Module 27 Connecting Tube 28 Common Piping 29 Cutting Position

Claims (10)

In a boiler having a casing formed of a membrane wall having a plurality of water pipes, at least a part of the wall surface,
A plurality of heat transfer tube panels disposed inside the casing;
A collecting pipe connected to the plurality of heat transfer tube panels and disposed outside the casing;
In the membrane wall, and a plurality of membrane wall opening is formed so as to allow loading and unloading said plurality of heat transfer tubes panel in and out of the casing,
Each of the plurality of membrane wall openings is formed between adjacent water tubes of the membrane wall so as to correspond to the plurality of heat transfer tube panels, and each of the plurality of heat transfer tube panels corresponds to each other. A boiler that can be inserted into the casing through a membrane wall opening .   The boiler according to claim 1, further comprising a sealing member that is detachably attached to the membrane wall in order to seal the opening of the membrane wall. Before Kifutome member, said plurality of membrane wall and the entire opening is formed as an integral member for sealing, according to claim 2 boiler according. The boiler according to claim 3 , wherein the sealing member is fixed to the membrane wall by a detachable fastener. The boiler according to any one of claims 1 to 4 , comprising a plurality of heat transfer tube modules each having a plurality of the heat transfer tube panels and the collecting tube to which the plurality of heat transfer tube panels are connected. The boiler according to claim 5 , wherein each of the plurality of collecting pipes is connected to a common pipe through each connecting pipe. The boiler according to claim 6 , wherein the common pipe is disposed at a position where a space for drawing out the heat transfer tube panel can be secured. A method for replacing a heat transfer tube in a boiler according to any one of claims 1 to 7 ,
Separating the collecting pipe to which the heat transfer tube panel is connected from the common pipe to which the plurality of collecting pipes are connected ;
Releasing the fixed state of the heat transfer tube panel to the membrane wall;
And a step of moving the heat transfer tube panel in the casing together with the collecting tube and pulling it out of the casing through the plurality of membrane wall openings . A method of replacing a heat transfer tube in a boiler according to claim 5 ,
Separating the collecting pipe to which the heat transfer tube panel is connected from the common pipe to which the plurality of collecting pipes are connected ;
Releasing the fixed state of the heat transfer tube panel to the membrane wall;
A step of moving the heat transfer tube panel in the casing together with the collecting tube and pulling it out of the casing through the plurality of membrane wall openings ,
A method for replacing a heat transfer tube, wherein the heat transfer tube panel is pulled out of the casing for each heat transfer tube module. A boiler heat transfer tube replacement method according to claim 7 ,
Separating the collecting pipe to which the heat transfer tube panel is connected from the common pipe to which the plurality of collecting pipes are connected ;
Releasing the fixed state of the heat transfer tube panel to the membrane wall;
A step of moving the heat transfer tube panel in the casing together with the collecting tube and pulling it out of the casing through the plurality of membrane wall openings ,
A method for replacing a heat transfer tube, wherein the heat transfer tube panel is drawn out between a pair of the common pipes.

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