JPS61143698A - Exhaust heat recovery heat exchanger - Google Patents

Abstract

PURPOSE:To effectively control the generation of thermal reaction power which occurs between heat exchange units as well as to enable to sufficiently correspond to the rapid rise of the temperature by the starting of the operation, by a method wherein heat exchange units are air-tightly connected by an expansion joint, and the load of the heat exchange units situated below are supported by supporting mechanisms. CONSTITUTION:Connecting parts 22 of each heat exchange device unit 15 are composed of the expansion joints 24 which air-tightly connect the heat exchange device units 15 and the supporting mechanisms 25 which support the load of heat exchanger units 15 situated below. Load receiving members 27 are fixed by welding between outside plate stiffeners 18 which are formed at the side of heat exchanger units 15, and on each these load receiving members 27 penetrating holes 28 are perforated. Cut channels 30 are formed at connecting flanges 29. A connecting rod 31 is inserted to the penetrating holes formed at the load receiving member 27, and nuts 32 are screwed at the upper and lower ends of the connecting rod 31, and a plate spring 33 for controlling the displacement is inserted between the nut 32 at the upper end and the load receiving member 27.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an exhaust heat recovery heat exchanger installed in a combined cycle turbine plant or the like.

[Technical background of the invention and its problems] In general, a combined cycle is a power generation system that increases plant efficiency by combining a gas turbine and a steam turbine, and one of its forms is exhaust heat recovery. There is something called shape.

Figure 6 is a system diagram of such an exhaust heat recovery type combined cycle power generation plant, in which gas turbine 1, l
[2 and a steam turbine 3 are arranged on one axis, and one exhaust heat recovery heat exchanger 4 is combined therewith as a steam generator.

That is, high-temperature, high-pressure combustion gas G1 produced by a combustor (not shown) flows into the gas turbine 1 and rotates it at high speed. The exhaust gas G2, whose pressure and temperature have been reduced by performing work in the gas turbine 1, is transferred to the exhaust heat recovery heat exchanger 4.
The water is introduced into the evaporator 5 and the economizer 6, which are made up of a large number of heat transfer tubes, to exchange heat with the feed water, and then is discharged from the outlet duct 7.

On the other hand, the economizer 6 is supplied with condensate from the condenser 8 of the steam turbine 3 via a conduit 10 by a pump 9, and hot water heated by the economizer 6 is guided to a drum 11; The hot water is heated in the evaporator 5 to become steam and is again supplied to the steam turbine 3 via the drum 11 and conduit 12.

Such an exhaust heat recovery heat exchanger is constructed by combining a plurality of heat exchanger units for each function in order to facilitate construction and to be compatible with various types of exhaust heat recovery heat exchangers.

Generally, an exhaust heat recovery heat exchanger is a fairly large structure because it processes a large amount of gas turbine exhaust gas, and several types of support methods are used.

Fig. 7 shows a device used in a relatively small-sized exhaust heat recovery heat exchanger, in which the exhaust heat recovery heat exchanger 4 itself, which is made up of a plurality of heat exchanger units 15, is made rigid and the exhaust heat recovery heat exchanger is It is constructed to be self-supporting and to absorb thermal expansion by the slide 14 of the base part 13.

FIG. 8 shows a semi-white vertical type exhaust heat recovery heat exchanger 4 used in the exhaust heat recovery heat exchanger 4 which is slightly larger than the one shown in FIG. The exhaust heat recovery heat exchanger 4 is supported by a supporting steel frame 16 at a center of gravity level near the center, and thermal expansion is absorbed by the bending or sliding of the supporting steel frame 16.

Figure 9 shows a hanging method used for a large-sized waste heat recovery heat exchanger.
is suspended via a hanging member 17,
In this system, since there is nothing to externally restrain the thermal expansion of the exhaust heat recovery heat exchanger 4 itself, no mechanism is particularly provided to absorb thermal expansion.

On the other hand, when the heat exchanger units 15 are combined to constitute one exhaust heat recovery heat exchanger, each heat exchanger unit 15 has a structure as shown in FIG. 10, for example.

That is, each heat exchanger unit 15 has a stiffener 18 welded to a side plate 17, and a tube plate 21 that supports heat transfer tubes 20 is welded to the side plate 17 in the box 19. Therefore, each heat exchanger unit 15 has a very high rigidity.

FIG. 11 shows how the heat exchanger unit 15 deforms when high-temperature exhaust gas flows into the heat exchanger unit 15, which has such a large rigidity.

In the figure, the gas temperature continuously decreases from the bottom to the top. Here, if the rigidity of the heat exchanger unit 15 is too high (if the structural strength changes continuously like a boiler water cooling wall), the heat exchanger unit 15 will change as the temperature changes, as shown by the dotted line a in the figure. Transforms into a trapezoid.

On the other hand, each heat exchanger unit 1 like the exhaust heat recovery heat exchanger
When the rigidity of the heat exchanger unit 5 is high, the heat exchanger unit 15 itself does not deform into a trapezoid due to thermal expansion and tries to maintain its rectangular parallelepiped shape. , an expansion difference occurs as shown by the solid line in the figure. Since the temperature at the bottom of each heat exchanger unit 15 is higher than that at the top, the heat exchanger unit 15 deforms into a slightly curved shape.

In conventional exhaust heat recovery heat exchangers, a mechanism for absorbing such a difference in thermal expansion is not provided, so a considerable force is applied to each heat exchanger unit 15 due to thermal stress caused by the difference in thermal expansion. was. Therefore, there is a problem that the exhaust heat recovery heat exchanger may be damaged or the heat exchanger unit 15 may be damaged due to low cycle fatigue due to thermal stress caused by plant operation.

Particularly in exhaust heat recovery heat exchangers used in combined cycle plants that are repeatedly operated and stopped every day, damage caused by low cycle fatigue caused by thermal stress has become a problem.

[Object of the invention] The present invention has been made in response to such conventional circumstances,
It is possible to effectively suppress the occurrence of thermal stress that occurs between heat exchanger units, prevent fatigue damage to the heat exchanger units, and provide exhaust heat that can sufficiently cope with temperature rises caused by sudden operation start-up. The aim is to provide a recovery heat exchanger.

[Summary of the Invention] That is, the present invention provides an exhaust system in which a plurality of heat exchanger units are stacked vertically in multiple stages via respective connection parts, and the heat exchanger unit located at the top is suspended and supported on a support beam. In the heat recovery heat exchanger, the connecting portion is configured with an expansion joint that airtightly connects the heat exchanger units, and a support mechanism that supports the load of the heat exchanger unit located on the other side, and the support mechanism is A load receiver protruding and fixed to the lower part of the heat exchanger unit disposed at the upper part and the upper part of the heat exchanger unit disposed at the lower part is a member;
The exhaust heat recovery heat exchanger is characterized in that these load receivers are constituted by a connecting mechanism that elastically connects the members.

[Embodiment J of the Invention The details of the present invention will be described below with reference to an embodiment shown in the drawings.

FIG. 1 shows an embodiment of the exhaust heat recovery heat exchanger of the present invention, and in the figure, reference numeral 4 indicates a plurality of heat exchanger units 15.
This shows exhaust heat recovery heat exchangers that are stacked vertically in multiple stages via connecting portions 22, respectively.

This exhaust heat recovery heat exchanger 4 has a U-shaped supporting steel frame 16.
The heat exchanger unit 15 located at the top is suspended and supported via a hanging rod 12. Support steel frame 1
A steam drum 23 is placed above the steam drum 6. The connection portion 22 of each heat exchanger unit 15 is connected to the heat exchanger unit 15.
It is comprised of an expansion joint 24 that airtightly connects between the two, and a support mechanism 25 that supports the load of the heat exchanger unit 15 located below.

In addition, the exhaust heat recovery heat exchanger 4 has a photographic stopper 26 disposed between the heat exchanger unit 15 and the supporting steel frame 16.
Its lateral movement is restricted.

FIG. 2 shows the details of the connection part 22, and there is an expansion joint 24 between the upper heat exchanger unit 15 and the lower heat exchanger unit 15 that airtightly connects the heat exchanger units 15. It is arranged. A load receiver is a member 2 between the outer plate stiffeners 18 formed on the side surface of the heat exchanger unit 15.
7 is fixed by welding, and this load receiver is attached to member 27.
A through hole 28 is bored in each of the holes.

Further, as shown in FIG. 3, notch grooves 30 are formed in the connection flanges 29 formed at the lower and upper ends of the heat exchanger unit 15. As shown in FIG. A connecting rod 31 is inserted into a through hole formed in the load receiver member 27 . A nut 32 is screwed into the upper and lower ends of the connecting rod 31, and a bellows spring 33 is inserted between the nut 32 at the upper end and the load receiver member 27 for adjusting displacement.

In the exhaust heat recovery heat exchanger configured as described above, the heat exchanger units 15 are connected by the expansion joints 24, so that the upper and lower heat exchanger units 1
Since 5 is relatively movable, it is possible to reliably eliminate the thermal stress that conventionally occurs between them.

Furthermore, when a thermal displacement occurs between the heat exchanger units 15 and 15, since the notch groove 30 is formed in the connection 7 flange 29, the connection rod 31 will tilt as shown in FIG. Therefore, thermal displacement between the heat exchanger units 15 can be reliably absorbed. Further, since the ratchet spring 33 is inserted between the nut 32 and the member 27 of the load receiver, thermal displacement that occurs in the vertical direction of the heat exchanger unit 15 can be reliably absorbed by the rattle spring 33.

In addition, in the embodiment described above, the notch 30 is formed in the connection 7 flange 29, so that the connection rod 31 can be viewed from the side through the through hole 27 formed in the member 27. It can be inserted into the interior, making it easy to assemble.

[Effects of the Invention] As described above, in the waste heat recovery heat exchanger of the present invention, the heat exchanger units are airtightly connected by expansion joints, and the load of the heat exchanger unit located below is supported by the support mechanism. Because of the support, the relative thermal displacement that occurs between the upper heat exchanger unit and the lower heat exchanger unit can be reliably absorbed by the expansion joint, which previously occurred between the heat exchanger units. Thermal stress can be eliminated.

In addition, load receivers are fixed to the lower part of the heat exchanger unit arranged at the upper part and the upper part of the heat exchanger unit arranged at the lower part, respectively, with members protruding from each other. Since they are connected, vertical thermal displacement of the heat exchanger unit can be reliably absorbed.

Therefore, the thermal stress that has conventionally occurred between heat exchanger units can be alleviated, and damage to the exhaust heat recovery heat exchanger due to thermal stress can be effectively prevented.

[Brief explanation of the drawing]

Fig. 1 is a side view showing one embodiment of the exhaust heat recovery heat exchanger of the present invention, Fig. 2 is a side view showing details of the connection part shown in Fig. 1, and Fig. 3 is a side view showing the details of the connection part shown in Fig. 2. ■A cross-sectional view along the line, Figure 4 is an explanatory diagram showing the movement of the connecting rod during relative displacement of the heat exchanger unit, Figure 5 is the insertion of the connecting rod into the through hole formed in the load receiver member. An explanatory diagram showing the method, Fig. 6 is a piping system diagram showing a combined cycle turbine plant, Fig. 7 is a side view showing a self-supporting exhaust heat recovery heat exchanger,
Figure 8 is a side view showing a half-white vertical type exhaust heat recovery heat exchanger, Figure 9 is a side view showing a hanging type exhaust heat recovery heat exchanger, and Figure 10 is an external view showing the heat exchanger unit. FIG. 11 is an explanatory view showing a modification of the heat exchanger unit. 15... Heat exchanger unit 24.
・・・・・・・・・・・・Expansion joint 27・・・・・・・・・
・・・・・・The load receiver is the member 30・・・・・・・・・・・・Notch groove 31・・・・・・・・・Connecting rod Fig. 1 Fig. 2 Fig. 3 Fig. 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 7 Figure 9

Claims (2)

[Claims] (1) In an exhaust heat recovery heat exchanger in which a plurality of heat exchanger units are stacked vertically in multiple stages via respective connecting portions, and the heat exchanger unit located at the top is suspended and supported on a support beam, The connecting portion is configured by an expansion joint that airtightly connects the heat exchanger units, and a support mechanism that supports the load of the heat exchanger unit located below, and the support mechanism is configured to connect the heat exchanger units located above. The heat exchanger unit is characterized by being composed of a load receiving member protruding from and fixed to the lower part of the exchanger unit and the upper part of the heat exchanger unit disposed at the lower part, and a connecting mechanism elastically connecting these load receiving members. Exhaust heat recovery heat exchanger. (2) The connection mechanism includes a connecting rod whose upper and lower parts are inserted into through holes formed in the load receiving members of the upper and lower heat exchanger units, respectively, and nuts that are screwed into the upper and lower ends of the connecting rod. and a spring inserted between the nut and the upper surface of the load receiving member.