JPH03117801A - Exhaust heat recovery boiler - Google Patents

Abstract

PURPOSE:To increase the flow rate in the pipe and maintain the heat recovery rate high even if the number of heat transfer pipes in the heat transfer panel increases by constituting a heat exchanger of a heat transfer panel that has a plurality of heat transfer pipes that are arranged in parallel, an inlet header, an outlet header, and an intermediate header. CONSTITUTION:In a heat transfer panel 18 a large number of heat transfer pipes 22 are arranged in a gas passage, and the heat transfer pipes 22 are substantially divided into two halves, the left section and the right section. To one end of a heat transfer pipe 22 on the right side (in an area (a)) an inlet header 19 is connected. On the other hand to one end of a heat transfer pipe 22 on the left side (area (b)) an outlet header 20 is connected. These inlet header 19 and outlet header 20 are completely separated, and a gas passing prevention plate 27 is arranged at the position which corresponds to the gap between both headers. And, the other ends 22 of all heat transfer pipes are connected to an intermediate header 25. When the inlet header 19 and outlet header 20 are divided as above mentioned, the gap between the heat transfer pipes 22 (a) and 22(b) becomes large, and the exhaust gas G passes through this gap and makes a short-pass so that the heat recovery rate is reduced. The gas passing prevention plate 27 prevents the short-pass and raise the heat recovery rate.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an exhaust heat recovery boiler, and particularly to a heat transfer panel structure used in a superheater, reheater, evaporator, and energy saver. It concerns improvements and economizers.

[Prior art I]

Recently, combined cycle plants have been attracting attention as a part of high-efficiency power generation. This combined cycle plant first generates electricity using a gas turbine, then recovers the heat retained in the exhaust gas discharged from the gas turbine using an exhaust heat recovery boiler, and then uses the steam generated by the exhaust heat recovery boiler to power the steam turbine. Both turbines generate electricity.

FIG. 7 is a schematic diagram of a conventional combined cycle plant.

In the same figure, a combustor 3 mixes fuel F from a fuel supply pipe 2 with combustion air from an air supply pipe 1 and burns the mixture.
The gas turbine 4 is rotated by the combustion gas, and the gas turbine 4 generates electricity.

The exhaust gas G discharged from the gas turbine 4 is introduced into the exhaust gas passage 6 of the exhaust heat recovery boiler 5.

This exhaust gas passage 6 has an economizer 7. An evaporator 8, a drier Is 9 and a superheater 10 are respectively arranged. Furthermore, in recent years, with the rise in gas turbine exhaust gas temperature, a reheater 29 may be disposed between the evaporator 8 and the superheater IO. On the other hand, the feed water WF, which is the fluid to be heated, is supplied from the water supply pump 11 through the water supply pipe 12 to the economizer 7, preheated to a predetermined temperature, and then supplied to the drum 9. Water supply W supplied to drum 9
F passes through the downcomer pipe 13 of the drum 9 to the evaporator 8 and the drum 9.
Natural circulation or forced circulation is carried out in this order, during which time the water is heated and separated into water and steam in the drum 9.

The water is returned to the downcomer pipe 13, evaporator 8 and drum 9.
The steam is sent to the superheater 10, where it is further elevated, and then supplied to the steam turbine 15 through the main steam pipe 14, where the steam turbine 15 generates electricity. If the reheater 29 is provided, the steam from the steam turbine 15 is sent to the reheater 29, where the steam is superheated, and the superheated steam is sent again to the steam turbine 15 to generate electricity. In addition, 16 in the figure is a generator, and I7 is a condenser.

FIG. 8 shows the economizer 7. Reheater 29 and superheater 10
FIG.

As shown in the figure, this heat transfer panel 18 is attached to an inlet header.
The water or steam introduced from 19 is heated by a large number of heat transfer tubes 22 arranged in parallel, flows from below to upward, is taken out by an outlet header 20, and is sent to the next heat transfer panel 18 via a connecting tube 21. move to.

In this way, in the conventional heat transfer panel 18, the inlet header 19
The fluid to be heated flows through the heat transfer tube 22 in only one direction from bottom to top, and flows from the outlet header 2o through the communication tube 21 to the next heat transfer panel 18.

[Problem that the invention attempts to solve■]

The heat transfer coefficient in the heat transfer tubes 22 in this type of heat transfer panel 18 is proportional to the 0.8th power of the flow velocity in the tubes, so the higher the flow velocity, the better the heat recovery rate, and conversely, the slower the flow velocity in the tubes, the better the heat recovery rate. Heat recovery rate is poor.

Recently, in order to shorten the on-site installation period, there is a tendency to replace the exhaust heat recovery boiler 5 with an exhaust heat recovery module 23 at the factory as shown in FIG. 9. In this case, as shown in the figure, the heavy transport equipment 2 is placed under the exhaust heat recovery boiler module 23.
4 (for example, a dolly) and transport the exhaust heat recovery boiler module 23 as it is to the construction site. Therefore, the width Ll of the exhaust heat recovery boiler 5 is determined by the width Ll of the heavy transport equipment 2 in order to accommodate the heavy transport equipment 24.
It is wider than the width L2 of No. 4, and considerably wider than the width L3 when the exhaust heat recovery boiler is not modularized.

Therefore, the number of heat transfer tubes in the heat transfer panel 18 also increases. Therefore, the flow velocity in each pipe decreases.

There is insufficient heat recovery. To compensate for this, it is necessary to increase the number of panels, which leads to problems such as increased weight, increased size, and uneconomical performance.

In order to solve these problems, a heat transfer panel 18 as shown in FIG.
Publication No. 07). This heat transfer panel 18 has a structure in which headers 19 and 20 arranged at both ends of a heat transfer tube 22 are each divided into a plurality of divided panels to form divided panels, and each divided panel is connected by a panel connecting pipe 21. In this way, compared to conventional heat transfer panels, the tube flow velocity in each heat transfer tube 22 can be increased, and heat recovery efficiency can be improved.

However, this configuration is not without problems. That is, the number of panel connecting pipes 21 increases according to the number of divisions of the heat transfer panel, but the presence of these panel connecting pipes 21 not only increases pressure loss but also may cause unbalanced flow. In particular, when an unbalanced flow occurs in a energy saver, there are parts of the heat exchanger tubes where water does not flow, which causes steam to be generated within the tubes and causes a water hammer phenomenon, which has the drawback of damaging the heat exchanger tubes.

[Conventional technology ■]

FIG. 12 is also a schematic configuration diagram of a conventional exhaust heat recovery boiler.

As shown in the figure, the superheater 41. The evaporator 42 and the economizer 43 are arranged in sequence. Water sent from a water supply pump (not shown) is introduced into the inlet of the economizer 43, and as it repeatedly rises and falls within the economizer 43, heat is absorbed. be led to.

The introduced water is mixed with canned water in the drum t145, turned into saturated steam in the evaporator 42, led to the superheater 41, superheated to a high temperature, and then supplied to a steam turbine (not shown).

In this exhaust heat recovery boiler, since the amount of evaporation decreases when the calorific value of the gas decreases, the water supply flow rate is adjusted by a water supply flow rate adjustment valve 46 disposed on the inlet side of the energy saver 43. At this time, due to the characteristics of the water supply pump, the internal pressure of the economizer 43 is maintained high even if the load decreases, thereby preventing steaming within the economizer 43. Especially when performing transformer operation, the superheater 4
1 and the evaporator 42, so maintaining the pressure of the economizer 43 at a high level using this method is effective in preventing steaming.

(Ill WllI that the invention attempts to solve) No. 12
In the exhaust heat recovery boiler configured as shown in the figure, fluid flushes at the outlet of the flow rate adjustment valve 44, and especially in variable pressure operation, the pressure difference between the inlet and outlet of the flow rate adjustment valve/I4 is large, and accordingly, the flushing becomes intense. , the wear of the flow rate regulating valve 44 becomes significant.

In order to prevent this from happening, it is necessary to design the outlet of the economizer 43 with a low fluid enthalpy. However, lowering the outlet enthalpy of the economizer 43 results in lowering the amount of evaporation in the exhaust heat recovery boiler.

This is not desirable in a combined cycle plant or the like, as it will lead to a decrease in plant efficiency.

The first object of the present invention is to eliminate the drawbacks of the prior art described above, and to provide waste heat that can increase the flow velocity in the tubes and maintain a high heat recovery rate even when the number of heat transfer tubes in the heat transfer panel increases. Our goal is to provide recovery boilers.

A second object of the present invention is to provide an exhaust heat recovery boiler that eliminates the drawbacks of the prior art mentioned above and can effectively prevent flushing at the flow rate regulating valve outlet even if the feed water temperature of one energy saving device intake is increased. be.

[Means I to solve problem a]

1 In order to achieve the first object, the present invention disposes heat exchangers such as a superheater, a reheater, an evaporator, and a carbon saver in the exhaust gas passage so that the exhaust gas flowing through the exhaust gas passage is In the waste heat recovery boiler in which the heat exchanger recovers the heat generated by the heat exchanger, at least one of the heat exchangers includes a plurality of heat exchanger tubes arranged in parallel and An inlet header connected to one end of some of the heat exchanger tubes, an outlet header connected to one end of the remaining heat exchanger tubes and disposed on the same side as the header 1, and facing the inlet header and the outlet header. The heat transfer panel is characterized in that it is comprised of a heat transfer panel having one intermediate header placed on the side where the heat transfer tubes are connected and connected to the other ends of all the heat transfer tubes.

In order to achieve the second object, the present invention provides an exhaust heat recovery boiler, in which at least an economizer is disposed in the exhaust gas passage, and the heat possessed by the exhaust gas flowing through the exhaust gas passage is recovered by the economizer. In.

The economizer includes a high temperature side economizer disposed upstream in the exhaust gas flow direction, a low temperature side economizer disposed downstream of the high temperature side economizer, and the low temperature side economizer. and an economizer connection pipe that communicates with the high temperature side economizer, the high temperature side economizer is composed of only an ascending pipe, and the low temperature side economizer is a combination of an ascending pipe and a descending pipe. It is characterized by being composed of.

In order to achieve the second object, the present invention includes at least an economizer disposed in the exhaust gas passage, the heat possessed by the exhaust gas passing through the curved exhaust gas passage dε is recovered by the economizer, and the energy efficiency is reduced. In an exhaust heat recovery boiler that is provided with a pressure regulating valve to prevent steaming from occurring within the boiler, the economizer is a high-temperature side economizer disposed on the upstream side in the flow direction of the exhaust gas; It has a low temperature side economizer disposed on the downstream side of the high temperature side economizer, and an economizer connection pipe that connects the low temperature side economizer and the high temperature side economizer, The high-temperature side economizer is composed of only an ascending pipe, and the low-temperature side economizer is composed of a combination of an ascending pipe and a downcomer pipe.

[Embodiments of the invention]

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

FIG. 1 shows a heat transfer channel according to a first embodiment of the present invention.

In the heat transfer panel 18 shown in the figure, a large number of heat transfer tubes 22 are arranged in a gas passage extending perpendicularly to the plane of the drawing, but the heat transfer tubes 22 are roughly divided into two on the left and right as viewed in the drawing. , a gas nozzle prevention plate 27 is inserted in the middle part.A ladder 19 is connected to the inlet at one end of the heat exchanger tube 22 (area a) on the right side as viewed from the drawing, and on the other hand, a ladder 19 is connected to the inlet of the heat exchanger tube 22 on the left side
An outlet header 20 is connected to one end of (area b). The header 1.1 header 19 and the outlet header 20 are completely separated, and as shown in FIG. 1, the gas pass prevention plate 27 is disposed at a position corresponding to the gap between them. Moreover, the other end of all the heat exchanger tubes 22 is.

It is connected to an intermediate header 25 provided at a position facing the inlet header 19 and the exit ladder 20, respectively.

In the heat transfer panel having this configuration, a fluid to be heated, such as water, is introduced from the inlet header 19.

It passes through the heat exchanger tube 22 on the area a side, passes through the ladder 25 to the middle,
After passing through the heat transfer tube 22 on the side of the area, it is discharged from the outlet header 20, and unlike the conventional type, the heated fluid flows in two directions.

In the embodiment of the present invention, the superheater 10, reheater 29, etc. shown in FIG. Of the evaporator 8 and the economizer 7, the superheater 10, the reheater 29, and the economizer 7, excluding the evaporator 8, are constructed of the heat transfer panel 18.

This is because heat is transferred within the heat transfer tube 22 of the evaporator 8 without boiling the fluid to be heated, so increasing the flow velocity within the tube has little effect on improving heat transfer efficiency.

On the other hand, since the fluid to be heated in the heat transfer tubes 22 in the superheater lO1 reheater 29 and the economizer 7 is one phase of only water or steam, increasing the flow rate improves the heat transfer efficiency accordingly. do.

As in this embodiment, the entrance ladder 19 and the exit header 20
If the heat exchanger tube 22a at the left end in area a is divided into
The gap between the heat exchanger tube 22b at the right end of the region inevitably becomes larger. In this case, the exhaust gas G passes through the gap and makes a short pass, reducing the heat recovery effect. Therefore, a gas pass prevention plate 27 is disposed to prevent the short pass and increase the heat recovery rate.

In the first embodiment, the entrance ladder 19 and the exit header 20
The gas pass prevention plate 27 was installed at a position corresponding to the gap, but in the case of the second embodiment shown in FIG. A plate 26 can also be inserted to differentiate the inlet header 19 and the outlet header 20.

In these first and second embodiments, the lengths of the inlet ladder 19 and the outlet header 20 are approximately equal, but in the case of the third embodiment shown in FIG. changing the length of

By alternating the lengths of the input header 19 and the outlet header 20 in this way, the heat of the exhaust gas that has made a short pass through the divided part of panel A is transferred to panel B located on the downstream side.
Gas pass prevention plate 27 of one divided part so as to recover heat with
can be made unnecessary. In this embodiment, the entrance ladder 19 is short and the exit header 20 is long; however, on the contrary, the entrance header 19 may be made longer and the exit header 20 may be made shorter.

The fourth and fifth embodiments shown in FIGS. 4 and 5 differ from the first and second embodiments in that the heat transfer panel 18 in FIGS. 1 and 2 is in a vertical position. In contrast, the heat transfer panel l8 in FIGS. 4 and 5 is placed horizontally,
Other explanations are the same as those in FIGS. 1 and 2.

FIG. 6 shows a sixth embodiment of the present invention.

In the case of a combined cycle plant, there is a drawback that steam is generated at the feed water outlet of the joint 'a7 of the exhaust heat recovery boiler when the gas turbine is started up or under low load. This is because the exhaust gas temperature at the inlet of the exhaust gas passage 6 shown in FIG. 7 is lower at startup and under low load than at high load. 29 and the heat transfer panel I8 of the evaporator 8 will absorb less heat.

Therefore, the exhaust gas temperature of the economizer 7 [1] becomes higher because the amount of heat absorbed by the superheater 10, reheater 29, and evaporator 8 decreases, and the temperature of the exhaust gas of the economizer 7 increases accordingly. On the contrary, the amount of heat absorbed increases, and as the amount of heat absorbed increases, the energy saving device 7
Of the heat transfer panels 18, steaming occurs in the heat transfer panel 18 that is close to the water supply outlet, that is, the heat transfer panel 18 on the upstream side when viewed from the flow of exhaust gas (the heat transfer panel 18 located upstream of the exhaust gas of the economizer 7). And when steaming occurs.

This is not preferable because water hammer may occur and the heat exchanger tubes 22 may be damaged.

Therefore, when all the heat transfer panels 18 shown in FIGS. 1 to 3 are used in the energy saver 7, the heat transfer panels 18 at the water supply outlet part
When steam is generated in the downflow heat transfer tube 22 flowing from the inlet header 19 of C to the intermediate ladder 25, there is a problem that the steam stagnates and causes water hammer.

Therefore, in the embodiment shown in FIG. 6, the heat transfer panel 18C at the water supply outlet where steam is expected to be generated is replaced with a heat transfer panel 18C that only has an upward flow. That is, the heat transfer panel 18 shown in FIG.
and other heat transfer panels +8D, 18F, 18F, 1
By using 8G and 1811 as the heat transfer panels 18 shown in FIGS. 1 to 3, the heat recovery rate in the economizer 7 is increased, and even if steam is generated, it is not stagnated and is transferred to the drum 9. It was designed to allow water to be supplied.

Here, when the area where steam is generated is wide, the heat transfer panel 18D is also a heat transfer panel 18 that only allows upward flow, and the diameter of the communication pipe connecting the heat transfer panels 18C and 180 is made small.
It is also possible to increase the flow rate in the communication pipe, eliminate steam stagnation, and send water supply from the heat transfer panel 18D to the heat transfer panel 18C.

FIG. 11 is a diagram for explaining a seventh embodiment of the present invention. As shown in the figure, a superheater 41. Evaporator 42. A high temperature side economizer 43b and a low temperature side economizer 43a are arranged in sequence.

The water supplied from the water supply pump (not shown) is mixed with an appropriate amount of high-temperature water in the economizer 43a to prevent low-temperature corrosion, and is heated above the dew point of the exhaust gas G (approximately 45°C) to save water. Charcoal maker 4
The water sent to the afuJAFJ 43a, which is supplied to the afuJAFJ 43a, repeatedly rises and falls, and after absorbing heat from the exhaust gas G, the water is transferred to the high temperature side economizer 43b, which is composed only of a riser pipe.
is supplied through the economizer connection pipe 47. If the high-temperature side economizer 43b is constructed of only the riser pipe in this way, even if steam is generated therein, it will not stagnate, and water hammer will not occur after all.

The fluid at the outlet of the high-temperature side economizer 43b (air-water temperature mixture containing water or steam) passes through the drum connection pipe 48 to the drum 4.
5, mixed with canned water in the drum 45, and then transferred to the evaporator 4.
2. The saturated steam generated in the evaporator 42 is separated into steam and water in the drum 45, and is led to the superheater 41 through the superheater connecting pipe 49, where it becomes superheated steam and is sent to a steam turbine (not shown).

Water supply control due to load changes in the exhaust heat recovery boiler.

This is carried out by a flow rate adjustment valve 46 provided in the middle of the economizer linking pipe 47 that connects the low temperature side economizer 43a and the high temperature side economizer 43b. Therefore, the inside of the low-temperature side economizer 43a can be maintained at a predetermined high pressure, and steaming within the low-temperature side economizer 43a can be prevented.In addition, the high-temperature side economizer 43b is composed of only a riser pipe. Therefore, even if steaming occurs, it will not be a problem, so it is possible to design a system that increases the fluid enthalpy at the inlet of the drum 45, and by increasing the amount of evaporation, it is possible to design a plant with higher efficiency such as a combined cycle plant. be able to.

Furthermore, if the amount of heat absorbed by the high temperature side economizer 43b is increased,
The number of evaporators can be increased accordingly, and the gas temperature of the low-temperature side economizer 43a is lowered, furthermore, steaming in the low-temperature side economizer 43a is less likely to occur.

In the middle of the drum connecting pipe 48 that communicates between the high temperature side economizer 43b and the drum 45, there is a pressure loss imparting part 50 made of an orifice or an orifice tube, etc., and a switching valve 51.
There is also a. When the fluid temperature at the outlet of the low-temperature side economizer 43a rises under partial load and flushing is likely to occur at the outlet of the flow rate regulating valve 46, the fluid is guided to the pressure loss imparting section 50 with a large pressure loss by the switching valve 48. This makes it possible to prevent flushing.

Furthermore, for this reason, it is possible to increase the fluid enthalpy at the inlet of the flow rate regulating valve 46 to near these limits, thereby further increasing the amount of evaporation.

It is possible to further improve plant efficiency.

〔Effect of the invention〕

This is because the present invention has the configuration described above.

On the other hand, since it is only necessary to divide or divide only some headers, it can be manufactured at a lower cost than those proposed in the past, and the flow velocity in the pipe can be increased, so that the heat recovery rate can be maintained at a high level.

Furthermore, since the present invention is configured as described above,
It has the advantage that flushing at the regulating valve outlet can be effectively prevented even if the water supply temperature at the outlet of the economizer is increased.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a heat transfer panel according to a first embodiment of the present invention. FIG. 2 is a plan view of a heat transfer panel according to a second embodiment. FIG. 3 is a plan view of a heat transfer panel group according to the third embodiment. FIG. 4 is a plan view of a heat transfer panel according to a fourth embodiment, and FIG. 5 is a plan view of a heat transfer panel according to a fifth embodiment. FIG. 6 is a schematic configuration diagram of the vicinity of the economizer of the exhaust heat recovery boiler according to the sixth embodiment. Fig. 7 is a schematic configuration diagram of a conventional waste heat recovery boiler, Fig. 8 is a perspective view of a conventional heat transfer panel, and Fig. 9 is an explanation showing a state in which the modularized Ill: heat recovery boiler is transported. Figure 10 is the conventionally proposed! 11. Outline of heat recovery boiler!
lI8 configuration diagram. FIG. 11 is a schematic diagram of an exhaust heat recovery boiler according to a seventh embodiment of the present invention. FIG. 12 is a schematic diagram of a conventional exhaust heat recovery boiler. 5... Exhaust heat recovery boiler, 6... Exhaust gas passage, 7... Energy saver, 8... Evaporator,
-9...Drum, 10...Superheater, 18.
... Heat transfer panel, 19 ... Inlet header, 20
... Outlet header, 22 ... Heat exchanger tube, 2
9... Reheater, 27... Gas pass prevention plate, 41... Superheater, 42... Evaporator 1.
43... Economizer, 43a... Low temperature side economizer, 43b... High temperature side economizer, 45...
...Drum, 46...Flow rate control valve, 47...
... Economizer connection pipe, 48 ... Drum connection pipe,
5゜...Pressure loss imparting part, 51...Switching valve. Figure 1 Figure 6 5 Figure 4 Figure Figure Figure Figure Figure 1O Figure

Claims (12)

[Claims] (1) Heat exchangers such as a superheater, reheater, evaporator, and energy saver are arranged in the exhaust gas passage, and the heat held by the exhaust gas flowing through the exhaust gas passage is transferred to the heat exchanger. In the waste heat recovery boiler, at least one of the heat exchangers is connected to a plurality of heat exchanger tubes arranged in parallel and one end of some of the heat exchanger tubes. an inlet header connected to one end of the remaining heat exchanger tubes and located on the same side as the inlet header; and an outlet header connected to one end of the remaining heat exchanger tubes and located on the same side as the inlet header, and an outlet header located on the side opposite to the inlet header and the outlet header and connected to all other heat exchanger tubes. 1. An exhaust heat recovery boiler comprising a heat transfer panel having an end and an intermediate header connected to the heat transfer panel. (2) In claim (1), the inlet header and the outlet header are separated, and a gas pass prevention member is disposed at a position corresponding to the gap between the inlet header and the outlet header in the heat transfer tube group. An exhaust heat recovery boiler featuring: (3) In claim (1), the inlet header and the outlet header are composed of one header, and the header is divided into the inlet header and the outlet header by providing a partition member in the middle of the header. An exhaust heat recovery boiler characterized by: (4) In claim (1), a large number of the heat transfer panels are arranged along the exhaust gas flow direction, the lengths of the inlet header and the outlet header in the heat transfer panels are different from each other, and the lengths of the inlet header and the outlet header are different from each other. The header is separated so that the gap between the inlet header and the outlet header of the heat transfer panel faces the inlet header or outlet header of the heat transfer panel that is disposed on the downstream side of the heat transfer panel in the exhaust gas flow direction. An exhaust heat recovery boiler characterized by comprising: (5) In an exhaust heat recovery boiler, in which at least an economizer is disposed in an exhaust gas passage, and the economizer recovers heat held by exhaust gas flowing through the exhaust gas passage, the economizer is arranged in the exhaust gas flow direction. A high-temperature side economizer placed upstream, a low-temperature side economizer placed downstream of the high-temperature side economizer, and the low-temperature side economizer and high-temperature side economizer are connected. The high-temperature side economizer is composed of only an ascending pipe, and the low-temperature side economizer is composed of a combination of an ascending pipe and a descending pipe. Characteristic exhaust heat recovery boiler. (6) In claim (5), the low-temperature side economizer includes a plurality of heat exchanger tubes arranged in parallel, and an inlet header connected to one end of some of the heat exchanger tubes. , an outlet header connected to one end of the remaining heat exchanger tubes and arranged on the same side as the inlet header, and an outlet header arranged on the side opposite to the inlet header and the outlet header and connected to the other ends of all the heat exchanger tubes. An exhaust heat recovery boiler comprising a heat transfer panel having one intermediate header. (7) In claim (6), the inlet header and the outlet header are separated, and a gas pass prevention member is arranged at a position corresponding to the gap between the inlet header and the outlet header in the heat exchanger tube group. An exhaust heat recovery boiler featuring: (8) In claim (6), the inlet header and the outlet header are composed of one header, and the inlet header and the outlet header are separated by providing a partition member in the middle of the header. An exhaust heat recovery boiler characterized by: (9) In claim (6), a large number of the heat transfer panels are arranged along the exhaust gas flow direction, the lengths of the inlet header and the outlet header in the heat transfer panels are different from each other, and the lengths of the inlet header and the outlet header are different from each other. The header is separated so that the gap between the inlet header and the outlet header of the heat transfer panel faces the inlet header or outlet header of the heat transfer panel that is disposed on the downstream side of the heat transfer panel in the exhaust gas flow direction. An exhaust heat recovery boiler characterized by comprising: (10) At least an economizer is disposed in the exhaust gas passage, and the heat held by the exhaust gas flowing through the exhaust gas passage is recovered by the economizer to prevent steaming from occurring within the economizer. In the exhaust heat recovery boiler equipped with a regulating valve for pressure adjustment, the economizer includes a high-temperature side economizer disposed upstream in the flow direction of the exhaust gas, and a high-temperature side economizer disposed downstream of the high-temperature side economizer. a low-temperature side economizer disposed in the lower temperature side economizer, and an economizer connecting pipe that connects the low-temperature side economizer and the high-temperature side economizer, and the high-temperature side economizer is composed of only a riser pipe. . An exhaust heat recovery boiler, characterized in that the low-temperature side economizer is constituted by a combination of an ascending pipe and a descending pipe. (11) The exhaust heat recovery boiler according to claim (10), wherein the regulating valve is provided in the middle of the economizer connecting pipe. (12) In claim (10), a drum communication pipe for communicating the high temperature side economizer and the drum is provided,
An exhaust heat recovery boiler characterized in that a pressure loss imparting section and a switching valve are provided in parallel in the middle of the drum communication pipe.