JPH0243081B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a method for forming a heat exchanger tube support, and particularly to a method for forming a heat exchanger tube support body for supporting finned heat exchanger tubes of a waste heat recovery boiler that recovers heat in gas turbine exhaust gas. The present invention relates to a method for forming a support that prevents resonance due to flow.

<Conventional technology and its problems> 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. In addition to high power generation efficiency, this plant has the advantage of high load responsiveness, which is a characteristic of gas turbines, and can sufficiently respond to sudden increases in power demand.

FIG. 1 shows the structure of a waste heat recovery boiler that recovers heat from turbine exhaust gas. In the figure, turbine exhaust gas G passes through a superheater 1 and a high-pressure evaporator 2, and then reaches a denitrification device 3, where nitrogen oxides (NOx) in the exhaust gas are removed. Subsequently, the exhaust gas is discharged through the high-pressure evaporator 4, the high-pressure economizer 7, the low-pressure evaporator 8, and the low-pressure economizer 11. The high-pressure steam S ₁ and low-pressure steam S ₂ generated during this time are used as a power source for the steam turbine and as 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. The waste heat recovery boiler configured as described above is arranged in a gas flow path through which gas turbine exhaust gas passes. In other words, waste heat recovery boilers recover heat by placing a large number of heat transfer tube groups such as evaporators and economizers in the gas flow, but as waste heat recovery boilers become larger, the height of these heat transfer tube groups increases. The length of the heat transfer tubes is 10 m or more, and it is a problem to prevent resonance caused by the gas flow in these heat transfer tube groups. Vibration of heat exchanger tubes is caused by a decrease in the strength of the heat exchanger tube as the tube itself becomes longer, which means that the tube becomes easier to bend, and gas flow disturbances such as Karman vortices act to promote this and generate resonance. Therefore, there is a need for a proposal for a method for forming a suitable heat exchanger tube support.

<Objective of the Invention> In view of the above-mentioned problems, the object of the present invention is to propose a method for forming a support that increases the holding strength of an enlarged heat exchanger tube and prevents resonance of a heat exchanger tube with fins, which is particularly difficult to hold. There is a particular thing.

<Summary of Means> In short, the present invention provides a method for forming a support for a plurality of heat exchanger tubes disposed in a combustion gas flow, in which a central tube disposed approximately in the center of a group of heat exchanger tubes is perpendicular to its axis. One of the longitudinal edges of the rectangle from the left and right in the plane is clamped by a central support plate having a U-shaped notch corresponding to each tube, the edges with the U-shaped notch are connected, and then the center row The tubes of the second tube row, which are parallel to the tubes and arranged on the left and right sides of the center row, are aligned with one of the longitudinal edges of the rectangle from the left and the right in a plane perpendicular to the axis of the tubes. The U-shaped notch of the second support plate having a U-shaped notch is inserted and supported, and the edge of the U-shaped notch is connected to the other longitudinal edge of the central support plate with a small rod interposed therebetween. A method of forming a heat exchanger tube support is characterized in that a third tube row disposed outside the second tube row is then supported in the same manner as the second tube row. .

<Example> An example of the present invention will be described below with reference to the drawings.

In FIGS. 2 and 3, reference numeral 12 denotes a heat transfer tube constituting the evaporator and economizer, to which fins 13 are attached to increase heat transfer efficiency. In FIG. 2, reference numerals 14a and 14b are central support plates integrated by welding 15, and preformed divided pieces 14a' and 14b' are arranged from both sides of the heat exchanger tube 12, respectively, and the contact surfaces It is attached by welding 15. Next, support plates are attached to the heat exchanger tubes in the row adjacent to the heat exchanger tubes to which the central support plate is attached in the following manner.

In FIG. 3, reference numeral 16 denotes a side support plate, which has a substantially U-shaped cut 16a formed therein so as to engage with the heat exchanger tube 12.
After arranging each heat exchanger tube 12 with respect to a, the tip edge 1
6b is brought into contact with the central support plate to perform welding. In this case, instead of directly connecting the support plates to each other, it is preferable to interpose the round rod 17 for connection.
A connection method using a round bar will be explained with reference to FIG.
For example, taking a round bar placed between the side support plate 16 and the central horizontal support plate 14a as an example, the round rod 17 is welded and connected only to the side of the central support plate 14a, and after the side support plate 16 is placed. It is connected to this round rod 17 by spot welding or the like.

As described above, by connecting the side support plates one after another to the central horizontal support plate, an integrated support plate is formed as a whole, and this support plate is arranged in one or more stages in the height direction of each heat exchanger tube.

FIG. 5 shows the arrangement of vertical support plates that makes the resonance prevention of the heat exchanger tubes more effective and the support more reliable. In the figure, reference numeral 18 denotes a vertical support plate, which is disposed along the flow of exhaust gas G and perpendicular to the integrally formed support plate. This vertical support plate 18 is formed as a single flat plate and is positioned sequentially according to the assembly process. When the heat exchanger tubes are arranged in a staggered manner as shown in the figure, the heat exchanger tubes are bent into a planar substantially corrugated shape so as to avoid these heat exchanger tubes. code 1
Reference numeral 9 indicates a support fitting attached to the heat tube adjacent to the vertical support plate 18. After the approximately U-shaped notch is inserted into the heat transfer tube, the end portion is welded to the vertical support plate. support. FIG. 6 is a drawing schematically showing the assembly order of these support plates and vertical support plates in alphabetical order (a to o).

By carrying out this invention, the heat exchanger tube, which has become longer, is effectively supported by the support plate, increasing the strength of the heat exchanger tube itself, and increasing the natural frequency of the heat exchanger tube to prevent resonance phenomena.

By arranging a vertical support plate in addition to this support plate, gas rectification can be made more effective and air column vibration can be prevented, thereby effectively preventing the generation of resonance vibration of the heat exchanger tube.

In addition, each support plate has a small diameter rod on the edge of the straight side, which facilitates the welding connection work with the adjacent support plate and prevents deformation of the planar plate formed by connecting the support plates. It also has the effect of acting as a preventive member.

[Brief explanation of the drawing]

Figure 1 is a side view of the boiler showing an outline of the waste heat recovery boiler, Figure 2 is a plan view of the support plate showing how the central support plate is attached, and Figure 3 is a plan view of the support plate showing how the side support plates are attached. 4 is a sectional view taken along the line A-A in FIG. 3, FIG. 5 is a perspective view showing how the vertical support plate is attached, and FIG. be. 12... Heat exchanger tube, 13... Fin, 14a, 1
4b...Central support plate, 16...Side support plate, 17
... Round bar, 18 ... Vertical support plate, 19 ... Support metal fittings.

Claims (1)

[Scope of Claims] 1. In a method of forming a support for a plurality of heat exchanger tubes arranged in a combustion gas flow, a central example tube arranged approximately at the center of a group of heat exchanger tubes is formed in a plane perpendicular to its axis. The left and right sides of the rectangular longitudinal edges are clamped by a center support plate having a U-shaped notch corresponding to each tube, and the edges with the U-shaped notches are connected, and then parallel to the tubes in the center row. Then, the tubes of the second tube row arranged on the left and right sides of the center row are made a U-shaped cut corresponding to each tube on one of the longitudinal edges of the rectangle from the left and right sides in a plane perpendicular to the axis of the second tube row. The U-shaped notch of the second support plate having a diameter is inserted and supported, and the edge of the U-shaped notch is connected to the other longitudinal edge of the central support plate with a small rod interposed therebetween. A method for forming a heat exchanger tube support, characterized in that a third tube row disposed outside the tube row is also supported in the same manner as the second tube row. 2. The heat exchanger tube group is partitioned into multiple stages by the support plate face pieces in the axial direction thereof, and vertical support plates for partitioning the gas flow into multiple flows are provided between the support plate face pieces for each stage, thereby forming a plate-like U-shape. 2. The method of forming a heat exchanger tube support according to claim 1, wherein the supporting metal fittings are connected to and held by a vertical support plate.