JP2000199601A - Boiler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make compact a boiler while ensuring the heat transfer area of a horizontal reheater being disposed in an exhaust gas channel on the downstream side of a boiler furnace. SOLUTION: A downstream side exhaust gas channel 21 being coupled with the upstream side exhaust gas channel 20 at the outlet of a furnace 1 is split into two and a horizontal reheater 7 is arranged in the split channel while being supported by a supporting pipe 18 also serving as a header. When the reheater is supported by such a supporting pipe 18 comprising heat transfer tubes, heat transfer area can be ensured effectively in a limited space of downstream side exhaust gas channel 21 and controllability of reheated steam temperature can be enhanced without increasing the size of the downstream side exhaust gas channel 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a boiler device, and more particularly to a heat exchanger installed in a downstream exhaust gas passage (also referred to as a rear flue portion) in an exhaust gas passage of a boiler furnace. The present invention relates to a boiler device suitable for supporting a heat transfer device without reducing its heat transfer area.

[0002]

2. Description of the Related Art The configuration of an entire boiler apparatus will be described with reference to FIG. In FIG. 5, high-temperature exhaust gas generated from a plurality of burners 2 provided in the lower part of the furnace 1 rises in the furnace 1. The exhaust gas passes through the upstream exhaust gas passage 20 and the downstream exhaust gas passage 21 and is discharged from the gas passage outlet 22 to the outside of the boiler as low-temperature exhaust gas. Upstream exhaust gas channel 2
At 0, a suspended primary superheater 3, a suspended secondary superheater 4, and a suspended tertiary superheater 5 are arranged in series along the flow of combustion gas. A suspended reheater 6 is disposed in the upstream exhaust gas passage 20 downstream of the suspended superheaters 3 to 5.

The exhaust gas flowing from the upstream exhaust gas channel 20 into the downstream exhaust gas channel 21 is separated from the horizontal reheater 7 arranged in one of the divided downstream exhaust gas channels 21 a partitioned by the partition wall 19 and the other. After heating the horizontal superheater 8 and the horizontal economizer 9 arranged in series in the divided downstream exhaust gas channel 21b, the gas is discharged downstream from the gas channel outlet 22. At this time, the flow rate of the exhaust gas is adjusted by the gas distribution dampers 10a and 10b provided at the downstream exhaust gas channel outlets 21a and 21b divided into two by the partition wall 19. Although not shown in FIG. 5, an evaporator may be provided between the horizontal superheater 8 and the economizer 9.

[0004] In the present specification, the term "horizontal type" means that a heat transfer tube group of a heat transfer device such as a reheater 7 is arranged in a direction substantially perpendicular to exhaust gas flowing in a vertical direction, that is, in a substantially horizontal direction. Say state. Further, in the present specification, the term “suspended type” means that heat transfer tubes of a heat transfer device such as the superheater 5 are arranged in a direction substantially orthogonal to exhaust gas flowing in a horizontal direction, that is, in a substantially vertical direction. Refers to a state in which the inlet and the outlet are disposed vertically upward.

[0005]

SUMMARY OF THE INVENTION In the boiler shown in FIG. 5, a downstream exhaust gas passage 2 in which a horizontal reheater 7 is installed is provided.
FIG. 6 shows only one of the divided gas flow paths 21a. The horizontal reheater 7 is a support member 2 at both ends of the reheater 7.
4 at both ends. When the horizontal reheater 7 is supported at both ends, the distance between the supporting points is limited in terms of strength. If the strength of the support members 24 at both ends of the horizontal reheater 7 exceeds the limit due to the increase in the capacity of the boiler or the like, conventionally, as shown in FIG. The economizer 9 'was arranged, and the horizontal reheater 7 was simultaneously supported by the economizer support pipe 25 provided to support the economizer 9'.

However, in the configuration shown in FIGS. 7 and 8, the economizer 9 'is disposed below the horizontal reheater 7, so that, for example, as shown in FIG. As a result, the downstream exhaust gas passage 21 becomes longer in the height direction, and the boiler is difficult to be compact. In addition, if the height of the downstream exhaust gas channel 21 is suppressed and the height of the downstream exhaust gas channel 21 is set as shown in FIG. As a result, the heat distribution area of the reheater 7 cannot be sufficiently secured, and the controllability of the outlet steam temperature of the reheater 7 by the gas distribution damper 10 deteriorates.

[0007] As described above, the additional installation of the economizer 9 'in the exhaust gas passage 21a below the horizontal reheater 7 not only imposes restrictions on the arrangement of the heat transfer surface, but also results in FIGS. 8
Since the outlet header 17 'of the economizer 9' is disposed above the outlet header 13 of the horizontal reheater 7 as shown in Fig. 7, a penthouse (not shown) surrounding these outlet headers 13 and 17 'is provided. And the height of the steel frame of the boiler is concomitantly increased, which contributes to an increase in cost.

Further, in order to maintain the steam temperature at the outlet of the reheater 7 when the load of the boiler drops, the distribution gas damper 10
When a large amount of exhaust gas flows to the horizontal reheater 7 side, if the economizer 9 ′ is installed on the horizontal reheater 7 side, steam is generated in the economizer 9 ′, so-called There was also a problem that teaming occurred.

As described above, the prior art described above does not take into account the increase in the capacity and compactness of the boiler, so that the height of the downstream exhaust gas passage 21 is increased or the transmission of the horizontal reheater 7 is not performed. There was a problem that the heat area was insufficient.

An object of the present invention is to secure a heat transfer area of a horizontal reheater arranged in an exhaust gas flow path on the downstream side of a boiler furnace,
Another object is to achieve a compact boiler.

[0011]

The above object of the present invention is attained by the following constitution. That is, the furnace, the upstream exhaust gas flow path that is connected to the outlet of the furnace via one end thereof, and the other end of the upstream exhaust gas flow path, which is divided along the flow of the exhaust gas. A downstream exhaust gas flow path having a divided gas flow path, a horizontal heat transfer device disposed in the downstream exhaust gas flow passage, and supporting the horizontal heat transfer device, The boiler includes a heat transfer tube that is a heat transfer tube that shares an inlet header and an outlet header. Here, means for controlling the flow rate of the exhaust gas flowing in the divided gas flow path can be provided at each outlet of the divided gas flow path.

An example of the horizontal heat transfer device of the boiler of the present invention is a reheater or a superheater, and one of the divided gas flow passages of the downstream exhaust gas flow passage of the boiler of the present invention is provided. A horizontal reheater may be arranged, and a superheater, at least a superheater and an economizer among the evaporator and the economizer may be arranged in the other divided gas flow path.

Generally, as means for controlling the temperature of the reheated steam flowing in the reheater, the flow rate and temperature of the exhaust gas from the furnace are varied by recirculating the exhaust gas from the gas flow path outlet into the furnace. , That regulates the amount of heat exchange in the reheater, that is equipped with a desuperheater at the inlet of the reheater and that sprays cooling water directly, or that the gas distribution damper at the outlet of the split gas flow path is opened and closed Something to control.

Among these, the controllability of the reheat steam temperature by the gas distribution damper depends on the amount of heat absorbed by the horizontal reheater (primary reheater) installed in the downstream exhaust gas passage (rear flue section) and the upstream It is determined based on the ratio of the amount of heat absorbed by the suspended reheater (secondary reheater) installed in the side exhaust gas flow path. The larger the ratio of the amount of heat absorbed by the horizontal reheater (primary reheater), The controllability of the reheat steam temperature by means (gas distribution dampers) provided at the respective outlets of the divided downstream exhaust gas channels and controlling the flow rate of the exhaust gas flowing in the respective divided gas channels is improved. In order to increase the heat absorption of the horizontal reheater, it is very effective to secure a large heat transfer area.

The structure for supporting a heat transfer device such as a reheater using a support tube according to the present invention can effectively secure a heat transfer area in a limited space of a downstream exhaust gas flow path, thereby enabling the downstream exhaust gas The controllability of the steam temperature in the heat transfer device such as the reheat steam temperature can be improved without increasing the size of the flow path.

Further, according to the present invention, the enthalpy of the internal fluid can be made the same as the inside of each heat transfer tube at least at the inlet header, and the internal fluid flowing from each inlet header to the corresponding outlet header can be adjusted. This means that the metal temperature difference between the heat transfer tubes when rising is small, and the structure of the connecting parts between the support tube and the reheater or the structure of the connecting parts between the support tube and the superheater is large. It is not necessary to provide them in consideration of the above, which simplifies and is advantageous for blocking.

Although the reheater has been described as an example of the horizontal heat exchanger, the same can be said for a horizontal superheater disposed in the exhaust gas flow path on the downstream side.

[0018]

Embodiments of the present invention will be described with reference to the drawings. In the embodiment of the present invention shown in FIG.
High-temperature exhaust gas generated from the plurality of burners 2 provided in the lower part of the furnace 1 rises in the furnace 1. The exhaust gas passes through the upstream exhaust gas passage 20 and the downstream exhaust gas passage 21 and is discharged from the exhaust gas passage outlet 22 to the outside of the boiler as low-temperature exhaust gas. A suspended primary superheater 3, a suspended secondary superheater 4, and a suspended tertiary superheater 5 are arranged in series in the upstream exhaust gas passage 21 in accordance with the flow of combustion gas. . A suspended reheater 6 is disposed in the upstream exhaust gas passage 20 on the downstream side of the superheaters 3 to 5.

The exhaust gas flowing from the upstream exhaust gas channel 20 into the downstream exhaust gas channel 21 is separated from the horizontal reheater 7 disposed in one of the divided downstream exhaust gas channels 21 a partitioned by the partition wall 19 and the other. After heating the horizontal superheater 8 and the horizontal economizer 9 arranged in series in the divided downstream exhaust gas channel 21b, the gas is discharged downstream from the exhaust gas channel outlet 22. At this time, the gas distribution dampers 10 provided at the downstream exhaust gas channel outlets 21a and 21b divided into two by the partition wall 19 are provided.
The exhaust gas flow rate is adjusted by a and 10b.

Although not shown in FIG. 1, the horizontal superheater 8
In some cases, an evaporator is installed between the evaporator and the economizer 9. The boiler shown in FIG. 1 has a horizontal reheater inlet header 12.
The reheated steam supplied to the reheater 7 is heated by the exhaust gas, passes through the outlet header 13 of the horizontal reheater 7, and passes through the connecting pipe (not shown) to the hanging reheater 6. Supplied.

Further, the steam supplied from the inlet header 14 is heated by the exhaust gas in the horizontal superheater 8 arranged in the downstream exhaust gas passage 21b, and the steam is supplied from the outlet header 1
5 and is supplied to the superheater 3 and the like in the upstream exhaust gas channel 20 via a communication pipe (not shown). Furthermore, the horizontal economizer 9 disposed in the downstream exhaust gas passage 21b
, High-temperature water is supplied from an inlet header 16, heated by exhaust gas, and supplied from an unillustrated pipe via an outlet header 17 to a furnace water cooling wall constituting a furnace wall from the bottom wall of the furnace 1. .

A reheater support pipe 18 extending in the vertical direction is installed in parallel with the horizontal reheater 7, and the reheater support pipe 18 is the same as the horizontal reheater 7 and has a horizontal reheater inlet pipe. The reheat steam is received from the drawer 12 and flows to the horizontal reheater outlet header 13 while supporting the horizontal reheater 7.

Compared with the conventional method of supporting the horizontal reheater 7 by the economizer 9 'shown in FIGS. 7 and 8, the structure shown in FIG. A standing reheater 7 can be arranged. In addition, the controllability of the reheat steam temperature is improved without reducing the heat transfer tube arrangement area of the horizontal reheater 7.

Since the economizer 9 is not installed in the downstream exhaust gas passage 21a where the horizontal reheater 7 is installed, FIG.
There is no problem that steam is generated in the economizer 9 'as in the prior art shown in FIG. 8, that is, steaming occurs.

Further, the structure for supporting the reheater 7 by the reheater support pipe 18 shown in FIG. 1 is a support member 24 shown in FIG.
The heat transfer area can be assured by the reheater support tube 18 as compared with the structure for supporting both ends of the reheater 7 by the above-described method.

Further, in the structure of supporting both ends of the reheater 7 by the support member 24, it is necessary to install each heat transfer tube constituting the reheater 7 on the support member 24 one by one at the construction site.
Installation costs were high. However, according to the support structure of the reheater 7 shown in FIG. 1, the reheater 7 can be made into a large-sized module, and its installation cost can be reduced as compared with the related art.

That is, it becomes possible to make the reheater 7 and its related members into a large module at the factory and manufacture it. At the construction site, the large module is simply jacked up and installation can be performed in a short period of time. Installation cost can be reduced.

FIG. 2 shows the reheater outlet steam temperature at the time of increasing the load in each of the prior art shown in FIG. 7 and the structure of the present invention shown in FIG. The reheater outlet steam temperature temporarily increases due to an increase in fuel flow rate due to the load increase. By reducing the gas flow rate on the side of the reheater 7 by the gas distribution damper 10, the rise in the steam temperature at the outlet of the reheater 7 is controlled.
Conventional structure with small heat transfer area of horizontal reheater 7 (Fig. 7)
Has a greater degree of temperature rise than the structure of the present invention (FIG. 1), and the reheat steam temperature controllability is poor. On the other hand, in the structure of the present invention (FIG. 1), the degree of the temperature rise is small, so that the rate of decrease in the reheat steam temperature caused by the reaction of the temperature rise is small, and as a result, the temperature can be set in a shorter time than in the conventional case.
Controllability has been significantly improved.

In the embodiment shown in FIG. 3 of the present invention, an example is shown in which the economizer 9 is provided below the horizontal reheater 7 installed in one of the divided downstream exhaust gas passages 21a. In this example, similarly to the case shown in FIG. 1, a reheater support pipe 18 extending in the vertical direction is installed in parallel with the horizontal reheater 7, and the reheater support pipe 18 is connected to the horizontal reheater 7. The reheat steam is received from the horizontal reheater inlet header 12 and supplied to the horizontal reheater outlet header 13 in the same manner as described above, and the horizontal reheater 7 is supported.

When the structure shown in FIG. 3 is compared with the conventional structure shown in FIG. 8, the economizer support tube 25 in the case of the structure shown in FIG. 8 is replaced by the reheater support tube 18 in FIG. The heat transfer area of the horizontal reheater 7 can be increased by the amount. Further, in the structure shown in FIG. 3, the outlet header 17 'of the economizer 9' is arranged above the outlet header 13 of the horizontal reheater 7, as compared with the conventional example shown in FIGS. Therefore, the height of the penthouse (not shown) surrounding the outlet header 13 does not increase, and the boiler steel frame height can be reduced.

The embodiment shown in FIG. 4 is similar to the reheater support pipe 18 shown in FIG. 1 except that the horizontal superheater 8 installed in the divided downstream exhaust gas passage 21b has the same structure as the reheater support pipe 18 shown in FIG. This is an example in which a structure having a tube 23 is applied.

That is, the economizer 9 is provided below the horizontal superheater 8, and the superheater support pipe 23 is installed in parallel with the horizontal superheater 8. The superheater support pipe 23 receives steam from the horizontal superheater inlet header 14 and flows it to the horizontal superheater outlet header 15 in the same manner as the horizontal superheater 8, and at the same time, the superheater support pipe 23, the horizontal superheater. The container 8 is supported. Also,
The economizer 9 puts hot water from its inlet header 16,
The high-temperature water is heated by the exhaust gas and discharged from the outlet header 17.

The structure shown in FIG. 4 does not improve the controllability of the reheater outlet steam temperature as compared with the prior art shown in FIGS. 7 and 8, but provides an effective heat transfer area to a limited space. In addition to reducing the height of the boiler steel frame and reducing the size of the penthouse by reducing the height of the penthouse, the height of the economizer outlet header 17 can be reduced, thus connecting the economizer outlet header 17 to the furnace inlet. The connecting pipe length can be reduced.

According to the above embodiment of the present invention, the enthalpy of the internal fluid is reduced by at least the inlet headers 12, 14,.
16 and 16 'can be made the same as the inside of each heat transfer tube, and the internal fluid flowing from each inlet header 12, 14, 16, 16' to the corresponding outlet header 13, 15, 17, 17 'respectively rises This means that the metal temperature difference between the heat transfer tubes during the heat transfer is small, and the structure of the connection part between the support tube 18 and the reheater 7 or the structure of the connection part between the support tube 23 and the superheater 8 is large. There is no need to consider the difference in thermal elongation, and it is simple, which is advantageous for blocking.

[0035]

According to the present invention, the horizontal heat transfer device can be effectively disposed in a limited space in the exhaust gas flow path on the downstream side of the boiler furnace. The controllability can be improved, the height of the boiler steel frame can be reduced by reducing the height of the penthouse, and a large module can be achieved. This can meet the demand for a large capacity and compact boiler.

[Brief description of the drawings]

FIG. 1 is a diagram showing a boiler structure in which a horizontal reheater according to an embodiment of the present invention is supported by a reheater tube.

FIG. 2 is a diagram showing a comparison between the controllability of the reheater outlet steam temperature when the boiler load increases according to the present invention and the prior art.

FIG. 3 is a diagram showing a partial structure of a downstream exhaust gas channel of a boiler in which a economizer is installed below a horizontal reheater according to an embodiment of the present invention.

FIG. 4 is a diagram showing a boiler structure in which a horizontal superheater according to an embodiment of the present invention is supported by superheater tubes.

FIG. 5 is a diagram showing a conventional boiler structure.

FIG. 6 is a view showing a boiler structure supporting both ends of a conventional horizontal reheater.

FIG. 7 is a diagram showing a partial structure of an exhaust gas flow path on the downstream side of a boiler that supports a conventional horizontal reheater by a economizer tube.

FIG. 8 is a view showing a structure of a part of a downstream exhaust gas flow path of a boiler which supports a conventional horizontal reheater by a economizer tube and reduces a heat transfer area of the horizontal reheater. .

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Furnace 2 Burner 3 Hanging primary superheater 4 Hanging secondary superheater 5 Hanging tertiary superheater 6 Hanging reheater 7 Horizontal reheater 8 Horizontal superheater 9, 9 'horizontal saver 10 gas distribution damper 12 horizontal reheater inlet header 13 horizontal reheater outlet header 14 horizontal superheater inlet header 15 horizontal superheater outlet header 16, 16' horizontal Storage economizer inlet header 17, 17 'Horizontal economizer outlet header 18 Reheater support pipe 19 Partition wall 20 Upstream exhaust gas channel 21 Downstream exhaust gas channel 21a, 21b Split downstream exhaust gas channel 22 Exhaust gas Flow path outlet 23 Superheater support tube 24 (both ends) support material 25 Energy saving device support tube

Claims (4)

[Claims] An upstream exhaust gas flow path communicated with a furnace through one end thereof to an outlet of the furnace; an upstream exhaust gas flow path connected to the other end of the upstream exhaust gas flow path; A downstream exhaust gas passage having a divided gas passage divided into two, a horizontal heat exchanger disposed in each of the divided gas passages, and supporting the horizontal heat exchanger. A boiler apparatus comprising: a heat transfer tube supporting a heat transfer tube that shares an inlet header and an outlet header of the heat transfer device. 2. The boiler device according to claim 1, wherein the horizontal heat exchanger is a reheater or a superheater. 3. A horizontal reheater is disposed in one of the divided gas passages of the downstream exhaust gas passage, and a superheater, an evaporator and a economizer are disposed in the other divided gas passage. 3. The heating device according to claim 1, wherein at least a superheater and a economizer are arranged.
The boiler device as described. 4. The apparatus according to claim 1, wherein each of the divided gas passages of the downstream exhaust gas passage includes means for controlling a flow rate of exhaust gas flowing in each of the divided gas passages. A boiler device according to any one of the above.