JPS60105801A - Waste liquor recovery boiler - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a waste heat recovery boiler, and more particularly to a boiler configured to improve the support of a header that constitutes a part of the boiler so as to better absorb stress caused by startup and stoppage.

Combined cycle power plants have recently been attracting attention as a part of high-efficiency power generation. This plant first generates electricity using a gas turbine, then recovers the heat in the exhaust gas discharged from the gas turbine in a waste heat recovery boiler, and uses the steam generated by the boiler to operate a steam turbine to generate electricity. It is.

In addition to high power generation efficiency, this plant has the advantage of having a gas turbine with high load responsiveness and being able to adequately respond to sudden increases in power demand.

FIG. 1 shows the structure of a waste heat recovery boiler that recovers heat from turbine waste gas. In the figure, the turbine exhaust gas G is on the superheater,
The gas passes through a high-pressure evaporator 2 to a tax evasion device 3, where nitrous oxides (NOx) in the exhaust gas are removed. Subsequently, the exhaust gas G is passed through another high-pressure evaporator (4) and a high-pressure economizer (7). Low pressure evaporator8. It is discharged through a low-pressure economizer 11. High pressure steam S generated during this time
1 and low-pressure steam S2 are used as a power source for a steam turbine and an internal heat source. In the figure, numerals 5 and 9 indicate a high-pressure drum and a low-pressure drum, respectively, and numerals 6 and 10 indicate downcomers.

Such a waste heat recovery boiler is placed in a gas duct that allows gas turbine exhaust gas to pass through, and the area around this gas duct is equipped with a heat-retaining structure to prevent heat dissipation to the outside and increase the heat recovery efficiency of the waste heat recovery boiler. It has become.

FIG. 2 shows a fragmented imj diagram of the heat exchange portion such as the superheater of the waste heat recovery boiler. In the figure, inside the duct casing 21 are an upper header 19 and a heat exchanger tube 12 that exchanges heat with the gas turbine waste gas G. Lower header 13 and upper connecting pipe 1
8. It is composed of a lower connecting pipe 20. Upper connecting pipe 18
．． Heat exchanger tube 12. Upper header 19. The weight of the lower header]-3 is supported by the foundation 17, and the entire boiler has a self-supporting structure. The necessity of arranging the lower connections 9Q and 20 between the lower header]-3 and the casing 21 and the need for heat insulation.
A certain amount of space is required to apply the four layers 16. For this purpose, the structure is such that the method of supporting the weight of the equipment is transmitted to the support beam 15 via the support lug 14 and then to the foundation 17. 3 is a sectional view taken along the line AA in FIG. 2. Heat exchanger tube 12. In order to support the weight of the lower r'tls header 13 and the upper i13 connecting pipe 18, the lower header 13 is provided with several support lugs 14 in the header longitudinal direction. In this structure, during operation, the lower header 1
The temperature of the pipe wall of No. 3 is almost equal to the fluid temperature inside the header, whereas the support beam 15 and casing 21 that support it are close to the outside air temperature due to the heat insulation layer 16, and therefore both A difference in thermal expansion occurs. Therefore, the support lug 14 is designed to absorb this difference in thermal expansion.
The space between the support beam 15 and the support beam 15 is made to slide in the direction of the header axis. The structure is such that it prevents overturning and movement in the direction A perpendicular to the header axis (see Figures 4 and 5). It is hoped that the child will be nourished.

(1) When sliding between the support lug 14 and the support beam 15, frictional resistance always occurs during sliding, and this sliding causes the distance L (Fig. 4, Fig. 5) A proportional bending moment acts on the lower pipe header 13, and stress is generated in the pipe header, which is an important equipment, and this stress is sure to occur when the engine starts or stops. In particular, this type of waste heat recovery boiler has good plant start-up characteristics, so it is frequently started and stopped, and moreover, it is started up quickly, so fatigue due to repeated l + i5 forces associated with the plant's restarting, stopping and correcting becomes a problem. .

2) - When the F section header 13 slides, the support lug 1
The insulation layer 16 placed around the reboot truck also has to move or deform, so that the insulation layer 16 and the support lug 1 have to move or deform.
A gap is formed between the support beams 15 and the casing 21, and the exhaust gas flows into the gap, causing the temperature of the support beam 15 and the casing 21 to rise, generating thermal stress, and further reducing thermal efficiency.

3) When the support lug 14 is directly welded to the lower header 13, the heat due to the header wall temperature is conducted to the lower end of the support lug, making it easier for the heat to be transmitted to the support beam 15, and the temperature of the support beam 15 increases. As a result, thermal stress is generated at the joint with the foundation 17 and the joint with the casing 21. From this point of view as well, it becomes difficult to withstand frequent startup and shutdown of the plant.

(4) When the support lug 14 is fixed to the lower header 3, since there are multiple support lugs 14 in the longitudinal direction of the header, the sliding surface of the support lug 14 may become horizontal due to deflection due to the lower header's own weight or manufacturing errors. As a result, the sliding surface may be inclined and hit unevenly, and this disadvantage becomes larger as the distance L between the header and the sliding surface becomes longer. Furthermore, in order to cope with this phenomenon, the sliding surface of the support lug must be machined, which increases manufacturing costs.

This invention has a structure in which the difference in thermal expansion due to the humidity difference between the header and the casing or support beam is absorbed by sliding, and the stress associated with sliding is reduced to eliminate the above-mentioned drawbacks of the prior art, and the number of times the boiler starts and stops is reduced. It is an object of the present invention to provide a boiler device having a header support part that can alleviate restrictions.

In short, the present invention is a boiler device in which a cradle is provided on a support beam, the header and the cradle are combined, and the header and the cradle are slid together.

Embodiments of the present invention will be described below with reference to the drawings.

6 and 7 show a first embodiment of the invention. In the figure, a pedestal 23 is fixedly attached to the support beam 15 by means such as welding, and a support lug 14 is placed on the pedestal.
A lower pipe header 13 with a As a result, the pedestal 23 is fixed on the support beam 15, and the support lug 14 is fixed on the lower header 13.

Therefore, the difference in thermal expansion due to the temperature difference between the lower header 13 and the support beam 15 is
The structure is such that it slides between the layers and absorbs it. The receiver pedestal 23 and the support beam 15 may be welded as shown in the figure, or may be fixed with a lip 22 as shown in FIGS. 4, 2, and 5. By combining the pedestal and the header with support lug in this way, the distance from the sliding surface to the header attachment part of the support lug: LI is the distance of the conventional structure minus the height L2 of the pedestal. Therefore, it is much smaller than the conventional structure, and the bending moment due to frictional resistance during sliding is significantly reduced, reducing the generated stress. If the stand 23 itself is fixed to the support beam 15, the heat insulating layer 16 will not be deformed (unlike in the conventional structure, there will be no gaps in the heat insulating layer, and the heat insulating effect will be improved). Furthermore, if the sabot beam 15 and the pedestal are fixed with the clips 22, the heat-insulating layer 4'A may have a slightly rhombic shape, but the absorbency of 176 particles will be further improved. Note that the contact structure is formed between the support lug 14 and the pedestal 23, and between the pedestal 23 and the support beam 15, making it difficult for temperature to be conducted compared to a conventional integral structure. In other words, since the heat transfer resistance increases in the contact structure, there is only one location in the conventional i′#/ structure.
-→ Su-+ , n) I-■ 1 cho+M Lbh
In this invention, where Nj+lJ=JJ+nn=r+, the heat transfer resistance can be increased, making it difficult to conduct the temperature of the header to the support beam 15. Therefore, thermal stress on the support beam and the casing connected thereto can be reduced.

FIGS. 8 and 9 show other embodiments, in which support lug 1
Taper the lower part of 4 and the minimum 1m area at the bottom is the cradle 2.
3, thereby making the sliding surface small and allowing smooth sliding even on the slope of the header 13.

Moreover, by reducing the contact area, the structure further increases heat transfer resistance. Also support lug 1
As shown in FIG. 10, the contact surface of No. 4 may be shaped like an arc or a curved line.

Note that the force in the direction perpendicular to the axis is dealt with by setting the stopper 24 to Il'tη.

Embodiments 1 and 2 described above have a heat insulating material layer 16 in common.
is arranged inside the casing, but it may also be arranged outside the casing 21.

11 and 12 show a third embodiment. In this embodiment, the pedestal is divided into an upper pedestal 25 and a lower pedestal 26, and the upper pedestal is combined with the lower pedestal 25. is fixed to the stand 26, and the lower support is fixed to the support beam 15. Therefore, sliding is absorbed between the support lug 14 and the upper support 25. Figure 12 is F- of Figure 11.
This is the F parent diagram.

According to this structure, the support lug 14 and the upper support form a contact surface between the base 25, the upper and lower support between the bases, and the lower support between the base 26 and the boat beam 15, so that the contact surface is 3.
Therefore, the heat conduction can be further reduced than in the embodiments shown in FIGS. 6 to 10. In this embodiment, two or more pedestals may be combined. In addition, one or more plates 27 are inserted between the upper and lower supports and between the lower support and the support beam for the purpose of adjusting the level of the support and increasing the contact surface, as shown in Figure 13A. It's okay. 1st
Figure 3E shows a modification of this example, in which a ring 28 is used instead of the plate 27 as a member interposed between the upper support and the stand 26.
This ring 28 is attached to the bolt 29. It is configured to be fixed with a nut 30.

FIG. 14 shows a fourth embodiment, in which two headers 13a,
13b are arranged on a common pedestal 23. According to this method, the manufacturing cost of the pedestal can be reduced. In the case of this structure, the number of headers supported by one holder may be two or more, and may be combined with support lugs 14 as shown in FIGS. 8 to 10. The pedestal as shown in FIGS. 1 to 13 may be divided into parts, and the plate 27 may be inserted between them. 15 and 16 show a fifth embodiment, in which the support lug 14 is completely eliminated and the header 13 is supported only by a cradle 35. That is, specifically, a pedestal 35 is provided on the support beam 15, the lower header 13 is placed on the pedestal, and the pedestal 35 is fixed to the support beam 15. Therefore, the structure is such that the difference in thermal expansion in the longitudinal axis direction of the header due to the humidity difference between the lower header 13 and the support beam 15 is absorbed by sliding between the lower header 13 and the pedestal 35. Further, an arc-shaped support plate 36 that conforms to the outer shape of the lower header 13 is attached to the cradle 35, allowing displacement in the axial direction of the header and restraining displacement in a direction perpendicular to the axis. . The receiver base 35 and the support beam 15 may be fixed with a lip 22 as shown in FIG. May be inserted.

With the above structure, the header 13 is completely released from the bending moment due to frictional resistance during sliding, and the stress acting on the header can be reduced.

FIGS. 17 and 18 show a sixth embodiment. In the case of this embodiment, the support beam 15 is arranged parallel to the pipe N, and a long beam-shaped pedestal 37 is arranged on the support beam of the bracket so as to be orthogonal to the support beam 15. Furthermore, a header 13 is installed above it. A stopper 36 is provided to support the force in the direction perpendicular to the header axis. Therefore, header 13
will slide on the pedestal 37. A plurality of headers 13 may be arranged on the pedestal 37, and the support beam 1
5 and the pedestal 37 may be fixed with a lip 22 as shown in FIGS. 6 and 7.

With this invention, thermal stress generated mainly in the lower header can be absorbed extremely effectively, so there is no risk of deformation or destruction of the tube body due to stress concentration, and it is sufficient for frequent and sudden startup and shutdown of boiler equipment. can correspond to

In addition, since a multi-stage contact structure is formed between the header and the casing, the heat transfer resistance increases and the heat retention of the entire boiler is also improved, resulting in an improved thermal effect.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of the structure of a brittle heat recovery boiler, Figure 2 is a detailed diagram of Figure 1, Figure 3 is a section 11ij of A-A in Figure 2, and Figure 4
The figures are a detailed view of section B in FIG. 2, FIG. 5 is a detailed view of section C in FIG. 3, FIG. 6 is a structural diagram of the header support according to the present invention, and FIG.
The diagram is a D-reference diagram of Figure 6, and Figure 8 is a second diagram according to the present invention.
A structural diagram of the header support part of the embodiment, FIG. 9 is E in FIG. 8.
-E main view, FIG. 10 is an enlarged view of FIG. 9, FIG. 13A and 13B are views showing a modification of the cradle structure shown in FIG. 11, and FIG. FIG. 15 is a structural diagram of a header support portion according to a fifth embodiment of the present invention, and FIG.
The parent diagram, FIG. 17 ("11η construction drawing of the header support part of the sixth embodiment according to the present invention, and FIG. 18 is the H-H parent diagram of FIG. 17. ...Lower support 14...Support lug 15...Support beam 23.35 ......The support is the stand 25...The upper support is the stand 26... ...The lower support is the stand 37...The long type support is the stand Patent Attorney Oka Tago Part 1jfljj':'54Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 11 Fig. 12 Fig. 14 Fig. 15 Fig. 16 Fig. 10 Fig. 17 Fig. 18

Claims (1)

[Claims] 1. In a device configured to support the load of each heat transfer tube group by arranging a group of heat transfer tubes in a passage through which heated gas passes and supporting a lower header of the group of heat transfer tubes. , characterized in that at least a part of the entire length of the support lug placed between the support beam supporting the load of the heat transfer tube group and the lower header is replaced with a cradle connected to the support beam side. Waste heat recovery boiler. 2. The waste heat recovery boiler according to claim 1, wherein the lower part of the support lug is tapered to reduce the contact area between the support lug and the pedestal. 3. The waste heat recovery boiler according to claim 1 or 2, wherein the receiver is a stand divided into a plurality of parts. 4. Elimination of any one of claims 1 to 3, characterized in that the receiver has a larger stand and is configured to support a plurality of lower pipe headers with the base stand. Heat recovery boiler. 5. A patent characterized in that the support lug is completely abolished, the lower header is supported only by the cradle, and the upper end of the cradle is fitted with a curved support plate that tightly engages the outer wall surface of the lower header. 6. The waste heat recovery boiler according to claim 1, wherein the pedestal is formed into an elongated beam shape, and the pedestal is arranged so as to be orthogonal to a support beam arranged parallel to the lower header. The waste heat recovery boiler according to claim 1, characterized in that the waste heat recovery boiler is stretched.