JPH08303705A - Supporting structure of heat transfer tube - Google Patents

Abstract

PURPOSE: To facilitate manufacturing works and prevent the breakage of a heat transfer tube. CONSTITUTION: Suspenders 25 are attached to the upper wall 24a of a flue 24, the steam ascending flow side and the steam descending flow side of the inside heat transfer tube 21a of a secondary superheater tube 21 are connected by a bent tube having a bent part, suspending lugs 27 are attached to the upper part of support pipes 28 having an outside diameter equal to the inside diameter of the bent parts of inside heat transfer tubes 21a, the suspending lug 27 is connected to the suspender 25 through a pin 29 to suspend the bent part of the inside heat transfer tubes 21a to the support pipes 28 of suspending balances 30, consisting of support pipes 28, suspending lugs 27 and pins 29.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a support structure for heat transfer tubes such as an exhaust heat recovery boiler.

[0002]

2. Description of the Related Art Recently, a combined power generation plant has been attracting attention as a part of high efficiency power generation. This combined cycle power plant first generates electricity using a gas turbine, recovers the heat in the exhaust gas discharged from the gas turbine with an exhaust heat recovery boiler, and operates the steam turbine with the steam generated in the exhaust heat recovery boiler to generate electricity. To do.

In addition to high efficiency of power generation, this combined cycle power plant has an advantage that it has a high load responsiveness due to the characteristics of the gas turbine and can sufficiently cope with a sudden increase in power demand.

FIG. 3 is a schematic view showing an exhaust heat recovery boiler having a conventional heat transfer tube support structure. As shown in the figure, a flue 2 through which exhaust gas G from a gas turbine (not shown) flows
4, the secondary superheater tube 21, the primary superheater tube 16 and the evaporator tube 1
1, the economizer pipe 3 is provided, the secondary superheater pipes 21 and the like are finned pipes, the secondary superheater pipes 21 and the like are staggered, and the secondary superheater pipes 21 and the like are hanging fittings 25 Flue 2
4 is supported by the upper wall 24a. Further, a water supply pump (not shown) and the downstreammost economizer economizer inlet header 2 are connected by a water supply pipe 1, and the economizer economizer outlet header 4 and the upstream economizer economizer inlet header 2 are connected. The uppermost streamlined economizer outlet port 4 and the steam drum 7 are connected by a drum water supply pipe 6, and the steam drum 7 and the evaporator inlet port 10 are connected by a coal pipe connecting pipe 5 and a downfall pipe 8 and water supply. Connected by a pipe 9, the evaporator outlet header 12 and the steam drum 7 are connected by an ascending pipe 13, the steam drum 7 and the primary superheater inlet header 15 are connected by a superheater inlet communication pipe 14, and the primary superheat The heater outlet pipe 17 and the secondary superheater inlet pipe 20 are connected by a superheater communication pipe 18, a desuperheater 19 is provided in the superheater communication pipe 18, a secondary superheater outlet pipe 22 and a steam turbine. (Not shown) is connected to the main steam pipe 23. It is connected Te.

In this waste heat recovery boiler, when water is supplied to the most downstream economizer economizer inlet pipe 2 via the water supply pipe 1 by the water supply pump, the water in the economizer economizer inlet pipe 2 is saved. The water collected through the pipe 3 to the economizer outlet header 4 and collected in the economizer outlet header 4 enters the upstream economizer inlet header 2 via the economizer connecting pipe 5. The water in the economizer inlet header 2 passes through the economizer pipe 3 and is collected in the economizer outlet header 4. Then, the water in the most upstream streamer economizer outlet pipe 4 enters the steam drum 7 via the drum water supply pipe 6, and the water in the steam drum 7 passes through the precipitation pipe 8 and the water supply pipe 9 to the evaporator inlet pipe. The water enters the port 10, the water in the evaporator inlet port 10 passes through the evaporator pipe 11, is collected in the evaporator outlet port 12, and enters the steam drum 7 from the evaporator outlet port 12 via the rising pipe 13. . On the other hand, the steam separated in the steam drum 7 enters the primary superheater inlet header 15 via the superheater inlet communication pipe 14, and the vapor in the primary superheater inlet header 15 passes through the primary superheater pipe 16. The steam collected in the primary superheater outlet header 17 and collected in the primary superheater outlet header 17 is connected to the secondary superheater inlet header 20 via the economizer connecting pipe 18.
to go into. In this case, the temperature of the superheated steam is controlled by the desuperheater 19. Then, the steam in the secondary superheater inlet pipe 20 passes through the secondary superheater pipe 21 and is collected in the secondary superheater outlet pipe 22, and the superheated steam collected in the secondary superheater outlet pipe 22 is It is supplied to the steam turbine via the main steam pipe 23.

In such an exhaust heat recovery boiler, the secondary superheater pipes 21 and the like are made up of finned pipes and the secondary superheater pipes 21 and the like are arranged in a staggered manner, so that heat can be recovered well. it can. Further, since the economizer inlet pipe header 2 and the like are provided in the lower portion of the flue 24, the drain in the pipe accumulated during the stop can be discharged, so that daily startup and stop can be promptly dealt with.

FIG. 4 is a front view showing a part of the exhaust heat recovery boiler shown in FIG. 3, that is, a conventional heat transfer tube support structure, and FIG. 5 is a side view showing the heat transfer tube support structure shown in FIG. . As shown in the figure, the hanging metal fitting 25 is attached to the upper wall 24a of the flue 24, the support pipe 26 is attached to the hanging metal fitting 25, and the secondary superheater pipe 21 includes the inner heat transfer pipe 21a and the outer heat transfer pipe 21b. In addition, the steam rising side and the steam descending side of the inner heat transfer tube 21a are connected by a bent tube having an arc-shaped bent portion having an inner diameter equal to the outer diameter of the support pipe 26, and the bent portion of the inner heat transfer tube 21a Are hung on the support pipe 26, and the steam upstream side and the steam downstream side of the outer heat transfer pipe 21b are connected by a straight pipe.

In this support structure for heat transfer tubes, the thermal expansion of the inner heat transfer tubes 21a and the outer heat transfer tubes 21b can be released to the lower secondary superheater inlet pipe header 20 and the secondary superheater outlet pipe header 22 side. Therefore, even if the amount of thermal expansion differs due to the difference in degree between the steam upstream side and the steam downstream side of the inner heat transfer tube 21a and the outer heat transfer tube 21b, the inner heat transfer tube 21
a, no thermal stress is generated in the outer heat transfer tube 21b.

[0009]

However, in such a support structure of the heat transfer tube, the inner heat transfer tube 21a is hung from the support pipe 26 by being attached to the upper wall 24a of the flue 24 via the hanging metal fitting 25. Therefore, when only a small number of bent portions of the inner heat transfer tubes 21a come into contact with the support pipes 26, the secondary superheater inlet pipe header 20, the secondary superheater 2
Since the total weight of the first and second superheater outlet pipes 22 acts on the small number of inner heat transfer pipes 21a, the small number of inner heat transfer pipes 21a may break. Therefore, in order to prevent breakage of the inner heat transfer tubes 21a, the inner heat transfer tubes 21a may be manufactured to have the same shape, or the support pipes 26 may be processed according to the finish of the inner heat transfer tubes 21a so that a large number of inner heat transfer tubes 21a. It is necessary to make the bent portion 21a contact the support pipe 26, but the manufacturing work is troublesome. In addition, even if many bent portions of the inner heat transfer tubes 21a are in contact with the support pipes 26 at the time of manufacturing, due to uneven flow of the exhaust gas G during operation, imbalance of the flow rate of steam in the secondary superheater tubes 21, and the like. The inner heat transfer tubes 21a may have different amounts of thermal expansion, and only a small number (two in the worst case) of the inner heat transfer tubes 21a may come into contact with the support pipe 26. 21a may break.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a support structure for a heat transfer tube which is easy to manufacture and which does not break the heat transfer tube.

[0011]

In order to achieve this object, in the present invention, in a heat transfer tube support structure in which a heat transfer tube is supported on an upper wall, a suspension balance is attached to the upper wall, A bent portion is provided on the upper portion, and the bent portion is hung on the suspension balance.

[0012]

In this heat transfer tube support structure, the bent portion of the heat transfer tube is brought into contact with the suspension balance without manufacturing the heat transfer tube in exactly the same shape and without processing the suspension balance according to the finish of the heat transfer tube. In addition, even if the thermal expansion amount of each heat transfer tube is different during operation, the bent portion of the heat transfer tube contacts the suspension balance.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a view showing a support structure for a heat transfer tube according to the present invention. As shown in the figure, the suspension lug 27 is attached to the upper portion of the support pipe 28 having an outer diameter equal to the inner diameter of the bent portion of the inner heat transfer tube 21a, and the suspension lug 27 and the suspension fitting 25 are connected by a pin 29. Suspension balance 3 with support pipe 28, suspension lug 27, and pin 29
0 is configured, and the support pipe 28 is rotatable around the center line of the pin 29. And the inner heat transfer tube 21
The bent portion a is hung on both sides of the support pipe 28.

In this heat transfer tube support structure, since the support pipe 28 is rotatable about the center line of the pin 29, the lengths of the inner heat transfer tubes 21a supported by the same support pipe 28 are different. Also, since the support pipe 28 is inclined and the bent portion of the inner heat transfer pipe 21a contacts the support pipe 28, the inner heat transfer pipes 21a evenly share the weight of the secondary superheater pipe 21 and the like. Therefore, it is not necessary to manufacture the inner heat transfer tube 21a in exactly the same shape, and it is not necessary to process the support pipe 28 according to the finish of the inner heat transfer tube 21a, so that the manufacturing work is easy. Even if the thermal expansion amount of each inner heat transfer tube 21a is different during operation, the support pipe 28 is inclined and the bent portion of the inner heat transfer tube 21a contacts the support pipe 28, so the inner heat transfer tube 21a is broken. Never.

FIG. 2 is a view showing another heat transfer tube support structure according to the present invention. As shown in the figure, a hanging lug 32 is attached to the upper part of the rotating member 31, and the hanging lug 32 and the hanging metal fitting 25 are connected by a pin 33.
1, the suspension lug 32, and the pin 33 constitute a support balance 34, and the rotating member 31 is rotatable around the center line of the pin 33. Further, support fittings 35 are attached to both sides of the lower part of the rotating member 31, and the hanging lug 27 and the support fitting 3 are attached.
5 and 5 are connected by a pin 29, and the bent portion of the inner heat transfer tube 21 a is hung on the support pipe 28.

In this heat transfer tube support structure, the rotating member 31 is rotatable about the center line of the pin 33, and the support pipe 28 is rotatable about the center line of the pin 29. Even if the lengths of the inner heat transfer tubes 21a are different, the rotating member 31, the support pipe 2
Since 8 bends and the bent portion of the inner heat transfer tube 21a contacts the support pipe 28, each inner heat transfer tube 21a evenly shares the weight of the secondary superheater tube 21 and the like.

In the above embodiments, the support structure of the secondary superheater pipe 21 of the exhaust heat recovery boiler has been described, but the present invention can be applied to other heat transfer pipe support structures. Further, in the above-described embodiment, although the four or eight inner heat transfer tubes 21a are supported by the hanging balance 30, other numbers of inner heat transfer tubes 21a may be supported by the hanging balance 30.

[0018]

As described above, in the heat transfer tube support structure according to the present invention, the heat transfer tube is not manufactured in exactly the same shape, and the hanging balance is not processed according to the finish of the heat transfer tube. Since the bent portion of the heat transfer tube can be brought into contact with the suspension balance, the manufacturing work is easy,
Also, even if the thermal expansion amount of each heat transfer tube is different during operation,
Since the bent portion of the heat transfer tube contacts the suspension balance, the heat transfer tube does not break.

[Brief description of drawings]

FIG. 1 is a view showing a support structure for a heat transfer tube according to the present invention.

FIG. 2 is a view showing another heat transfer tube support structure according to the present invention.

FIG. 3 is a schematic view showing an exhaust heat recovery boiler having a conventional heat transfer tube support structure.

FIG. 4 is a front view showing a conventional heat transfer tube support structure.

5 is a side view showing a support structure for the heat transfer tube shown in FIG. 4. FIG.

[Explanation of Codes] 21 ... Secondary Superheater Tube 21a ... Inner Heat Transfer Tube 24a ... Upper Wall 30 ... Suspended Balance

Claims (1)

[Claims] 1. A heat transfer tube support structure in which a heat transfer tube is supported on an upper wall, wherein a hanging balance is attached to the upper wall, a bent portion is provided on an upper portion of the heat transfer tube, and the bent portion is hung on the hanging balance. Support structure for heat transfer tubes.