JPH0122557B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a method for assembling a heat exchanger, and in particular, a method for assembling a heat exchanger, in which a group of heat exchanger tubes configured in a serpentine shape is supported by a plurality of support lattice frame units. The present invention relates to a method for assembling a heat exchanger.

[Technical background of the invention and its problems] A power generation system that generates steam by using the exhaust heat possessed by high-temperature gas discharged from a gas turbine and uses this steam as working steam for the steam turbine uses exhaust heat recovery. This is known as a combined cycle power plant.

Figure 1 shows an example of this type of combined cycle power generation plant, in which high-temperature, high-pressure exhaust gas discharged from a gas turbine 1 is sent to an exhaust heat recovery heat exchanger 3 via an exhaust pipe 2. .

The exhaust gas that has entered the exhaust heat recovery heat exchanger 3 flows upward, passes through the evaporator 4 and the economizer 5, and exits from the outlet duct to a chimney (not shown).
The evaporator 4 and economizer 5 are composed of a large number of heat transfer tubes 6 formed in a meandering shape, and steam and water flow through these tubes. Heat exchanger tube 6 constituting economizer 5
One end is connected to a condenser 8 via a water supply pipe 7, while the other end is connected to a canned water portion of an evaporation drum 9. Further, one end of the heat transfer tube 6 constituting the evaporator 4 is connected to a steam chamber of a steam drum 9, and the other end is attached to a canned water section via a pump 10. Further, a main steam pipe 11 is connected to the upper end of the steam drum 9, and the main steam pipe 11 is connected to a turbine inlet of a steam turbine 12. Furthermore, a condenser 8 is installed on the outlet side of the steam turbine 12. has been done.

In such a configuration, exhaust steam from the steam turbine 12 becomes condensed water in the condenser 8, and is force-fed to the economizer 5 from the water supply pipe 7 by the water supply pump 13. The feed water preheated by the economizer 5 flows into the can water section of the steam drum 9. The canned water in the steam drum 9 is fed from the bottom of the drum to the evaporator 4 by the transfer pump 10, evaporated in the heat transfer tube to become steam, and returned to the steam chamber of the steam drum 9 again.
The steam in the steam drum is extracted from the steam in the drum, introduced into the steam turbine through the main steam pipe 11, performs work in the steam turbine, and then returns to the condenser 8.
flows into.

It has been confirmed that in such an exhaust heat recovery type combined cycle power plant, the thermal efficiency of the plant is increased by several percent compared to conventional plants because the high temperature gas turbine exhaust gas is effectively used.

By the way, the above-mentioned waste heat exchanger is composed of a heat exchange shell, which serves as a high-temperature, high-pressure gas passage for exhaust from the gas turbine, a steamer, and an economizer 5. The serpentine heat exchanger tubes 6 must be firmly held within the heat exchanger shell.

For this purpose, the meandering heat exchanger tube is usually supported near both ends by a tube support lattice frame, and this tube support lattice frame is composed of a plurality of support lattice frame units 15 ₁ , 15 _{2 .} . . 15n, as shown in FIG. Each supporting lattice frame unit 15 includes hexagonal lattice frames 16, 16, .
... 16, and the heat exchanger tubes 6 are arranged in these lattice holes 16.

However, the tube support lattice frame of the conventional heat exchanger described above has multiple support lattice frame units adjacent to each other,
Since the joints are welded together, the lattice holes at the edges of each supporting lattice frame unit are left as empty spaces, and since no serpentine heat transfer tubes are incorporated, the serpentine heat exchanger tubes are not incorporated. Since the number of heat tubes is reduced, it is not possible to increase the heat transfer area, which causes a decrease in the performance of the heat exchanger.

[Object of the Invention] The object of the present invention is to increase the heat transfer area by making it possible to easily attach meandering heat transfer tubes to the boundary between adjacent support lattice frame units.
An object of the present invention is to provide a method for assembling a heat exchanger that can improve heat exchange performance.

[Summary of the Invention] The present invention provides a structure in which a set of meandering heat exchanger tubes is supported by the lattice holes of a support lattice frame unit, and a tube support lattice frame is constructed by joining several support lattice frame units next to each other. In the method for assembling the heat exchanger described above, the meandering heat exchanger tubes are temporarily fastened to the half-cut lattice holes formed at the edges of the support lattice frame unit using combustible and fusible thin strings, and then the meandering heat exchanger tubes are attached to the adjacent lattice holes. After the support lattice frame units are connected and assembled into the heat exchange shell, the thin strings are melted and removed by high temperature gas introduced into the heat exchange shell. .

[Embodiments of the Invention] Examples of the method for assembling a heat exchanger according to the present invention will be described below.

First, referring to FIGS. 3 and 4 for the assembly process of the meandering heat exchanger tube 6, four straight tubes 17 are arranged on a plane at equal intervals, and the tips of the straight tubes 17 are connected to the vent tube 18. to produce a serpentine heat exchanger tube that is approximately W-shaped as a whole as shown in FIG. Several of these meandering heat exchanger tubes are assembled as a monodule into the lattice holes 16 of the support lattice frame unit 15. Although various methods of assembly can be considered, in the case of the embodiment of the present invention, the meandering heat exchanger tubes are assembled by sandwiching them between a plurality of band lattice members 20.

That is, as shown in FIG. 5, the band lattice member 20 has trapezoidal peaks 20a and troughs 20b alternately formed.
The straight pipe 17 of the meandering heat exchanger tube is accommodated in the valley part 20b of
Another band lattice member is stacked on top of the band lattice member, and as shown in FIG. Assemble it so that it looks like this. Then, the upper ends of the several band lattice members 20 are fixed with the upper stopper frame 22, and the lower parts of the band lattice members are fixed with the lower stopper frame 23, completing the lattice frame unit as a module (see Fig. 2). ). A plurality of these support lattice frame units are placed adjacent to each other with their side ends abutted against each other, and their joined ends are joined to form a tube support lattice frame as a whole.

According to the present invention, the support lattice frame units 15 are also assembled into the lattice holes 16 at the boundaries between the support lattice frame units 15 by the assembly procedure described later.

That is, at the other end of the supporting lattice frame unit 15 there are half-cut lattice holes 21. As shown in FIG. 7, the serpentine heat exchanger tube 6 is temporarily fastened to the grid hole 21 with a flexible and soluble thin string 24, for example, a plastic string, and the supporting grid frame unit 15 and the supporting grid are connected as they are. The frame units 15 are joined adjacent to each other, and the peak portions 20a of each other are welded together. In the embodiment of the present invention, the work of arranging a plurality of support lattice frame units next to each other and welding their joints together is carried out after they are assembled into the heat exchange shell of the exhaust heat recovery type heat exchanger. is preferred.

After the required number of supporting lattice frame units are connected adjacently and the entire tube supporting lattice frame is assembled as described above, the meandering heat exchanger tubes are temporarily fastened and the thin strings 24 remain. During operation of this heat exchanger, when high-temperature, high-pressure exhaust gas discharged from the gas turbine 1 is introduced into the heat exchange barrel, the thin strings 24 are burned, melted, and removed.
If such an assembly procedure is followed, the serpentine heat exchanger tubes can also be installed at the boundaries of the connected supporting lattice frame units.

[Effects of the Invention] As described above, according to the present invention, meandering heat exchanger tubes are temporarily fastened with flammable and soluble thin strings in semi-dimensional lattice holes formed at the joint ends of adjacent supporting lattice frame units. Since the supporting lattice frame unit is welded together after the support lattice frame unit is attached, the thin strings melt and disappear due to the high temperature gas introduced into the heat exchanger cylinder during operation, and the threads meander into the lattice holes at the boundary of the supporting lattice frame unit. Can hold heat exchanger tubes.

Therefore, the heat transfer area can be increased by increasing the number of meandering heat transfer tubes, and the performance of the heat exchanger can be improved.

[Brief explanation of drawings]

Figure 1 is a system diagram showing an example of an exhaust heat recovery type combined cycle power generation plant, Figure 2 is a perspective view showing meandering heat exchanger tubes supported by a tube support lattice frame, Figures 3 and 4. Figure 5 is a plan view showing the manufacturing process of a meandering heat exchanger tube, Figure 5 is a perspective view showing one meandering heat exchanger tube placed in the valley of a band lattice member, and Figure 6 is a straight meandering heat exchanger tube. Fig. 7 shows a state in which the heat exchanger tube is temporarily fixed at the boundary between two supporting grid frame units. FIG. 3...Exhaust heat recovery heat exchanger, 6...Meandering heat exchanger tube,
17... straight pipe, 18... bent pipe, 20... band lattice member, 21... lattice hole.

Claims (1)

[Claims] 1 Method of assembling a heat exchanger in which a set of meandering heat exchanger tubes is supported by the lattice holes of a support lattice frame unit, and a tube support lattice frame is constructed by joining several support lattice frame units next to each other. In this step, the meandering heat exchanger tubes are temporarily fastened to the half-cut lattice holes formed at the edges of the supporting lattice frame units using flammable and fusible thin strings, and then adjacent supporting lattice frame units are connected to each other. . A method for assembling a heat exchanger, characterized in that, after being assembled into a heat exchange shell, the thin strings are melted and removed by high temperature gas introduced into the heat exchange shell.