JPH0355723B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a method for manufacturing an exhaust heat recovery heat exchanger,
In particular, the present invention relates to a method of manufacturing an exhaust heat recovery heat exchanger in which a group of meandering heat exchanger tubes is supported by a plurality of support lattice frame units.

[Technical background of the invention and its problems]

A power generation system that generates steam using the exhaust heat possessed by high-temperature gas discharged from a gas turbine and uses this steam as working steam for a steam turbine is known as an exhaust heat recovery type combined cycle power generation plant.

Figure 1 shows an example of this type of combined cycle power plant.
The high temperature and high pressure exhaust gas discharged from the exhaust pipe 2
The waste heat is sent to the exhaust heat recovery heat exchanger 3 via.

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 constructed of meandering heat exchanger tubes 6, through which steam and water flow.

One end of the meandering heat exchanger tube 6 constituting the economizer 5 is connected to a condenser 8 via a water supply pipe 7, while the other end is connected to a canned water section of the steam drum 9. Further, one end of the meandering heat transfer tube 6 constituting the evaporator 4 is connected to a steam chamber of a steam drum 9, and the other end is connected to a canned water section via a water supply 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 steam turbine 12.
A condenser 8 is connected to the turbine inlet of the steam turbine 12, and furthermore, a condenser 8 is installed on the outlet side of the steam turbine 12.

In such a configuration, exhaust steam from the steam turbine 12 becomes condensed water in the condenser 8, and is supplied 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. Canned water in the steam drum 9 is fed from the bottom of the drum to the evaporator 4 by a water supply pump 10, evaporated in the meandering heat transfer tube 6 to become steam, and returned to the steam chamber of the steam drum 9 again. It is extracted from the upper part of the steam drum in the steam drum 9, introduced into the steam turbine 12 through the main steam pipe 11, performs work in the turbine, and then flows into the condenser 8 again.

In such an exhaust heat recovery type combined cycle power generation plant, the high temperature gas turbine exhaust gas is effectively used, so the plant thermal efficiency is several percent lower than that of conventional plants.
It has been confirmed that it will rise.

By the way, the above-mentioned exhaust heat recovery heat exchanger includes a heat exchange shell 14 that serves as a passageway for high-temperature, high-pressure gas exhausted from the gas turbine, and an evaporator 4 disposed within the heat exchange shell 14.
It is mainly composed of an economizer 5. The evaporator 4 and the economizer 5 are constituted by a plurality of meandering heat exchanger tubes 6, which are firmly held within the heat exchange shell 14 via a supporting grid frame unit.

The supporting lattice frame unit is arranged near both ends and in the middle of the meandering heat exchanger tube 6, and as is clear from FIG. It was constructed by drilling holes 16,...16. and,
In order to incorporate the meandering heat exchanger tubes 6 into the support plate 15, the straight tubes 6a constituting the meandering heat exchanger tubes 6 are attached to the support plate 15 one by one.
After passing through the through hole 16 of the straight pipe 6a, a U is attached to the end of the straight pipe 6a.
It was assembled by sequentially connecting the vent pipes 6b and welding the fitting portions.

However, in the conventional waste heat recovery heat exchanger assembled as described above, a plurality of through holes 16 are bored in the support plate 15 constituting the support lattice frame unit, and the through holes 16 are formed in the support plate 15 constituting the support lattice frame unit. Since the strength of the support lattice frame unit is reduced by keeping the distance between the edges of the pair of through holes 16, 16 below a certain limit, the thickness of the support plate 15 must be increased to ensure the strength. Not only does this increase the weight of the supporting lattice frame unit, but it also makes it difficult to drill holes with high precision. Furthermore, when inserting the straight pipe 6a of the meandering heat exchanger tube 6 through the support plate 15, the meandering heat exchanger tube 6 bends due to its own weight and comes into strong contact with the wall of the through hole 16, which increases resistance and prevents the insertion operation. It takes a long time, and the contact during insertion causes scratches and constrictions on the surface of the straight tube 6a, causing damage to the meandering heat exchanger tube 6. In addition, the through holes 1 of a large number of support plates 15, 15, 15
It is actually difficult to accurately align the tubes 6, 16, and 16 in a straight line, which makes it difficult to insert the straight tube 6a of the meandering heat exchanger tube.

Furthermore, since the installation and welding of the U-bent pipe 6b must be performed after the straight pipe 6a has been inserted between the support plates 15, the support plate 15 becomes an obstacle during welding and welding inspection of the U-bent pipe 6b. The work was difficult. In addition, if a welding defect in the U-bent pipe 6b is discovered through a water pressure test, various problems arise, such as having to decide on the U-vent pipe 6b and then pull out the straight pipe 6a, which is cumbersome. .

[Purpose of the invention]

An object of the present invention is to combine band members in a lattice pattern to form a support member for meandering heat exchanger tubes, thereby making it possible to easily incorporate the meandering heat exchanger tubes into a support lattice frame unit, and to control the direction of the band members. It is an object of the present invention to provide a method for manufacturing an exhaust heat recovery heat exchanger that can maintain the mounting position of a meandering heat exchanger tube at a normal position by setting the meandering heat exchanger tube in a direction effective for preventing displacement of the meandering heat exchanger tube.

[Summary of the invention]

The manufacturing method according to the present invention includes a plurality of serpentine heat exchanger tubes in which both ends of at least three straight tubes placed parallel to each other are joined by two U-bent tubes, and crests and valleys of the serpentine heat exchanger tubes. A plurality of lattice band members formed alternately and consecutively with a pitch equal to the pitch of the straight pipes are prepared, and the straight pipe portions of the first meandering heat exchanger tubes are arranged in the valleys of the first lattice band members, The troughs of the second lattice band member are placed on the peaks of this lattice band member to fix them, and the straight pipe portions of the second meandering heat exchanger tubes are placed on the troughs of the second lattice band member. By placing the troughs of the third lattice band member on the peaks of this lattice band member and fixing them, repeating the arrangement of the serpentine heat exchanger tube and the fixing with the lattice band member, the serpentine heat exchanger tube is formed. A supporting lattice frame unit is constructed which holds the lattice at the lattice part, and then an upper frame supporting one end of each lattice band member is attached to one end of the supporting lattice frame unit, and the other end of each lattice band member is attached to the other end of the supporting lattice frame unit. A tube bundle module is constructed by arranging lower frames that support the ends of the tube bundle module, and then the tube bundle module is held approximately horizontally with the upper frame and the lower frame on suspension means installed vertically on the wall above the heat exchange cylinder. The present invention is characterized in that the meandering heat exchanger tubes are suspended so that the direction in which their own weight acts coincides with the longitudinal direction of each lattice band member.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 3 shows a perspective view of an exhaust heat recovery heat exchanger manufactured by the method of the present invention, and in the figure, the heat exchange cylinders 14 of the exhaust heat recovery heat exchanger are erected in parallel at a distance. a pair of side panels 20, 20,
A plurality of cross beams 21 are laterally spanned between the upper ends of these side panels 20, 20 at intervals. In the embodiment, these cross beams 21 are constructed of I-shaped steel, and a tube support lattice frame 23 is suspended below the cross beams 21 via hangers 22, 22, . . . , 22. These pipe support lattice frames 23 are made by combining and joining a plurality of support lattice frame units, and each support lattice frame unit has its upper edge connected to the upper frame 24, and
The lower edge is joined using a lower frame 25. These tube support lattice frames 23 are equipped with a large number of hexagonal hole-shaped lattice holes 26, 26, . A meandering heat exchanger tube 6 is supported. Incidentally, the meandering heat exchanger tube 6 is usually supported at three places: both ends and the center.

Next, the assembly procedure for supporting the meandering heat exchanger tube 6 on the supporting lattice frame unit will be explained. First, the assembly process of the meandering heat exchanger tubes 6 will be explained with reference to FIGS. 4 and 5. For example, four straight tubes 6a, 6
a, 6a, and 6a are arranged on a plane at equal intervals, and the tip of the straight pipe 6a is welded to the three U-bent pipes 6b, so that the overall shape is approximately W-shaped, as shown in Fig. 5. It is finished as a meandering heat exchanger tube 6.

Since no other members are involved until the W-shaped meandering heat exchanger tube 6 is finished, welding work and leakage inspection are not restricted by other members, and the work can proceed without any support. can.

Several of these meandering heat exchanger tubes 6 are assembled as one module within the lattice openings 26 of the supporting lattice frame unit as follows. That is, the serpentine heat exchanger tube 6 is assembled by sandwiching the front and rear parts between the pair of lattice band members 27. As is clear from FIGS. 6 to 8, the lattice band member 27 has trapezoidal peaks 2.
This is a strip in which valleys 7a and troughs 27b are alternately and continuously formed.

In the actual manufacturing process, Figures 7 and 8
As shown, one lattice band member 27
The meandering heat exchanger tube 6A is suspended from above A, and another lattice band member 27B is placed on top of the hexagonal lattice 2.
After stacking the lattice band members 27A and 27B so as to form a lattice band member 6, the joint portions of the adjacent lattice band members 27A and 27B may be joined by spot welding, for example.

Next, the second serpentine heat exchanger tube 6B is placed in the valley of the lattice band member 27B, and the lattice band member 27C is further stacked and welded thereon, and the same operation is repeated to form a transportable serpentine heat exchanger tube 6. A support lattice frame unit is constructed as one unit. Then, the upper frame 24 and lower frame 25 shown in FIG. 3 are assembled to both ends of the supporting lattice frame unit as one unit, thereby constructing the entire unit as a movable tube bundle module. Each process up to configuring this tube bundle module can be assembled independently without regard to the heat exchange cylinder 14, allowing for efficient work in a work environment with few restrictions by using a wide work space. be able to.

Thereafter, the tube bundle module with the meandering heat transfer tubes 6 assembled thereto is carried into the heat exchange shell 14 in order to be combined with the separately manufactured heat exchange shell 14, and the upper frame 24 and the lower frame 25 are kept almost horizontally so that the upper wall surface It is hung and fixed on the hangers 22, 22, 22...22 lowered from below. At this time, the lattice band members 27 of the lattice unit supported by the upper frame 24 and lower frame 25, which are kept substantially horizontal, are uniformly oriented in the vertical direction.

FIG. 9 shows the arrangement relationship between the meandering heat exchanger tube 6a and the lattice band member 27 after assembly is completed. The direction in which the weight of the meandering heat exchanger tube 6a acts coincides with the longitudinal direction of the lattice band member 27, and no deflection occurs in the lattice band member 27.

In the above embodiment, the peaks and troughs of the lattice band member were formed into trapezoidal shapes, and the lattice meshes of the supporting lattice frame unit were hexagonal, but the present invention is not limited to this. Alternatively, the shape of the grid may be square.

〔Effect of the invention〕

Furthermore, the meandering heat exchanger tube 6 of the above embodiment is composed of four straight pipes 6a and three U-bent pipes 6b, but this is composed of three straight pipes 6a and two or more U-bent pipes. If configured, the same desired effects as in the above embodiment can be obtained.

As explained above, in the present invention, since the lattice band members are combined to form a support member for the meandering heat exchanger tube, there is no particular difficulty in assembling the meandering heat exchanger tube into the support member, and it can be easily implemented. It's hot,
Work efficiency can be significantly improved.

Furthermore, since the orientation of the upper frame and lower frame provided at both ends of the lattice band member is kept almost horizontal, and the lattice band member is oriented in a direction without displacement, the meandering heat exchanger tube can be placed in the correct position. is possible,
It is possible to protect meandering heat exchanger tubes from unexpected accidents.

[Brief explanation of drawings]

Fig. 1 is a system diagram showing an example of an exhaust heat recovery type combined cycle power generation plant, Fig. 2 is a perspective view showing a conventional supporting lattice frame unit that supports meandering heat exchanger tubes, and Fig. 3 is a system diagram showing an example of a combined cycle power generation plant with waste heat recovery. 4 and 5 are plan views showing the manufacturing process of the meandering heat exchanger tube, and FIG. 6 is a perspective view showing the manufacturing process of the meandering heat exchanger tube. FIG. 7 is a perspective view showing a state in which three meandering heat exchanger tubes are connected by a lattice band member, FIG. 8 is a side view showing the same supported state, and FIG.
The figure is a perspective view showing a part of the meandering heat exchanger tubes supported by the lattices of the support lattice frame unit. 3...Exhaust heat recovery heat exchanger, 6...Meandering heat exchanger tube,
14... Heat exchange cylinder, 24... Upper frame, 25... Lower frame, 26... Lattice, 27... Lattice band member.

Claims (1)

[Claims] 1. A plurality of meandering heat exchanger tubes in which both ends of at least three straight tubes placed parallel to each other are joined by two U-bent tubes, and the peaks and valleys are connected to the pitch of the straight tubes of the meandering heat exchanger tubes. Prepare a plurality of lattice band members formed in succession alternately with pitches equal to , and arrange the straight pipe portions of the first meandering heat exchanger tubes in the valleys of the first lattice band member. The troughs of the second lattice band member are placed on the peaks of the lattice band member to fix them, and the straight pipe portion of the second meandering heat exchanger tube is placed on the trough of the second lattice band member. The troughs of the third lattice band member are placed on the peaks of the lattice band member to fix them, and by repeating the arrangement of the serpentine heat exchanger tubes and the fixing with the lattice band member, the serpentine heat exchanger tubes are arranged in the lattice pattern. A support lattice frame unit is constructed to hold the support lattice frame unit in place, and then a top frame supporting one end of each lattice band member is provided at one end of the support lattice frame unit, and the other end of each lattice band member is attached to the other end of the support lattice frame unit. A tube bundle module is constructed by arranging supporting lower frames, and then the tube bundle module is held approximately horizontally by suspension means vertically installed on the wall surface above the heat exchange cylinder. A method for manufacturing an exhaust heat recovery heat exchanger, characterized in that the meandering heat exchanger tubes are suspended so that the direction in which their own weight acts coincides with the longitudinal direction of each lattice band member.