JP4553365B2 - Hot water / steam combined heat exchanger - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a hot water / steam combined heat exchanger used for heat recovery of exhaust gas, supply of hot water or steam to a facility equipped with a micro gas turbine power generator, etc. It is mainly used for improving thermal efficiency, improving the electrical output of a turbine generator, and the like.

  In recent years, micro gas turbine power generators have been widely put into practical use. This is because the micro gas turbine power generator is small and excellent in economic efficiency, has high start-up characteristics and load fluctuation responsiveness, can supply steam and hot water in parallel with electric power, and hardly causes environmental pollution.

FIGS. 5 and 6 show an example of a utilization system of this kind of micro gas turbine power generator. FIG. 5 enables supply of hot water by exhaust heat recovery, and FIG. 6 enables supply of steam. It is.
5 and 6, 41 is an intake filter, 42 is a compressor, 43 is a turbine, 44 is a high-speed generator, 45 is a regenerative heat exchanger, 46 is a combustor, 47 is a frequency converter, and 48 is a transformer. , 49 is a hot water generator, 50 is a hot water pump, 51 is an exhaust heat boiler, 52 is a bypass valve, and 53 is a water supply pump.

  The air sucked through the intake filter 41 is pressurized and compressed by the compressor 42, and then this compressed air Ah is sent to the regenerative heat exchanger 45 where it is heated by the high-temperature combustion gas from the turbine 43. The heated compressed air Ah is mixed and burned with fuel in the combustor 46, and the generated high-temperature combustion gas Gh is sent to the turbine 43 and expands, so that so-called turbine work is performed. Is given.

  The rotational driving force of the turbine 43 is transmitted to the compressor 43 and the high speed generator 44 through the drive shaft, and the generated power from the high speed generator 44 is converted into a commercial frequency by the frequency converter 47 and then supplied to the power load. The Further, the exhaust gas G discharged from the regenerative heat exchanger 45 is supplied to the hot water generator 49 (or the exhaust heat boiler 51), and hot water (or steam) is generated by recovering the exhaust heat here.

Permanent magnet generators are often used for the high-speed generator 44, and are selected to have an output of 30 to 300 kW and a rotational speed of about 65,000 to 100,000 RPM.
In addition, since this kind of micro gas turbine power generator itself is already publicly known, detailed description thereof is omitted here (JP 2002-4942, JP 2002-4944, etc.).

  Thus, although the micro gas turbine power generator has many excellent practical utilities as described above, the power generation efficiency is about 25 to 30% in a small device with an output of 30 to 300 kw. There is a difficulty that the power generation efficiency is several percent lower than that of the gas engine power generation device.

Further, when the temperature of the intake air rises, the so-called turbine power decreases, and the generator output decreases.
FIG. 7 shows the result of measuring the relationship between the intake air temperature and the generator output using an actual machine (output 60 kw, manufactured by Capstone, USA). If the intake air temperature is up to 20 ° C., the rated output 60 kw is maintained. However, if the intake air temperature rises to 32 ° C., the generator output decreases to about 51 kW (down about 15%) (curve A).
For this reason, measures such as cooling the intake air are taken in the summer, but problems such as an increase in equipment costs and running costs arise.

Furthermore, in equipment using a gas turbine power generator, heat recovery of turbine exhaust gas is performed by a hot water generator or a waste heat boiler in order to increase thermal efficiency.
However, it is usually configured in a system that generates either hot water or steam, and when both hot water and steam are required, steam generated in the exhaust heat recovery boiler (or from the exhaust heat recovery boiler) Hot water is generated using exhaust gas).

As a result, when only the hot water generator is provided, it is not possible to cope with the decrease in the generator output in summer by injecting steam into the driving fluid of the gas turbine as described later, On the contrary, when only the exhaust heat boiler is installed, it is possible to cope with a decrease in the output of the generator, but it cannot meet the demand for the hot water load.
Furthermore, in order to be able to cope with both heat loads of steam and hot water, two types of equipment and devices for generating steam and hot water will be installed, which not only increases equipment costs and maintenance management costs, but also heat. There is a difficulty that the recovery rate decreases.

In the gas turbine, it is possible to increase the turbine output, that is, the generator output by injecting steam into the driving fluid of the gas turbine (for example, the compressed air Ah or the combustion gas Gh in FIG. 5). I understand.
Curves B and C in FIG. 7 show changes in the generator output when the intake air temperature is 32 ° C. (curve B) and 22 ° C. (curve C), and the amount of injected steam / intake air is a parameter. When the intake air temperature is 32 ° C., the generator output can be increased to the rated value (60 kW) by injecting a steam amount of about 4 to 6%. This is the same when the intake air temperature is 22 ° C., and the generator output can be restored to the rated value (60 kW) with the injection of the steam amount of 2 to 6%.

  The micro gas turbine generator used for the steam injection test has a control system configured to maintain the maximum output at 60 kw, and the generator output exceeds 60 kw by increasing the amount of steam injection. However, since the input to the turbine (the amount of heat of the combustion gas Gh) is controlled so as not to increase automatically beyond the set value, the generator output is increased to 60 kw or more by steam injection. It cannot be raised.

  On the other hand, in facilities equipped with gas turbine power generators, such as convenience stores and factories, the hot water load generally decreases in summer, but the power load increases. In winter, the hot water load increases.

  As a result, the exhaust heat recovery equipment and devices that use the gas turbine power generator can be switched between steam generation and hot water generation. Is operated as an exhaust heat boiler, a part of the generated steam is injected into the turbine drive system to increase the generator output, and the remaining steam corresponds to the heat load. Further, it is most desirable to operate the exhaust heat recovery device / device as a hot water generator and supply hot water in winter when the gas turbine generator does not cause a decrease in output and the hot water load increases. It can be said that it is a system.

JP 20024942 JP 2002-4944

  The present invention relates to the above-described problems in the power or heat / power supply system provided with the conventional gas turbine power generator, namely, When cooling the intake air to prevent a decrease in generator output during the summer, the equipment and running costs cannot be reduced. When exhaust heat recovery is performed only with a hot water generator, it is impossible to cope with a decrease in generator output in the summer, and c. When the exhaust heat recovery is performed only by the exhaust heat boiler, the demand for hot water cannot be met; When exhaust heat recovery is performed using both a hot water generator and an exhaust heat boiler, not only will the equipment and running costs increase, but also the overall heat recovery efficiency will be reduced. Yes, with a single exhaust heat recovery device / equipment, it is possible to easily switch between steam generation and hot water generation, so that it is possible to meet the demand for increased generator output and meet the demand for hot water in winter. The present invention also provides a warm water / steam combined heat exchanger that can be easily manufactured, has a simple structure, is compact, and can be manufactured at low cost.

The invention of claim 1 is the exhaust heat recovery unit 2 for the exhaust gas G, the hot water generation unit 3 integrated with the exhaust heat recovery unit 2, and the heat transfer water Wo is supplied to the exhaust heat recovery unit 2 and the hot water generation unit 3. In the hot water / steam combined heat exchanger, which is provided with a water supply unit section 4 that can appropriately switch between steam and hot water, the exhaust heat recovery section 2 is used for a plurality of heat exchanges between the upper header 34 and the lower header 35. A multi-tube once-through heat recovery body 40 connected by a pipe 36, an exhaust gas inlet side duct 31 connected to the inlet side of the heat recovery body 40, an economizer 8 connected to the outlet side of the heat recovery body 40, and an exhaust gas outlet side duct 32 And the warm water generating section 3 of the body 37, the heat exchange pipe 14 for hot water provided in the body 37, the steam extraction valve 9 communicating with the body 37, and the heat exchange pipe 14 for hot water. Hot water supply valve 11 and hot water litter communicating with both ends Each is formed from the valve 12., between the barrel 37 and the upper header 34 via the main communicating pipe 27 of large diameter, also between the body portion 37 and a lower header 35 to each connected via a communication pipe 28 together to integrate the Lehigh heat recovery unit 2 and the hot water generator 3, in which the body portion 37 of the hot water generator 3 at the time of occurrence of the steam has a configuration to steam-water separator.

The invention of claim 2 is the exhaust heat recovery unit 2 of the exhaust gas G, the hot water generation unit 3 integrated with the exhaust heat recovery unit 2, and the heat transfer water Wo is supplied to the exhaust heat recovery unit 2 and the hot water generation unit 3 In the hot water / steam combined heat exchanger, which is provided with a water supply unit section 4 that can appropriately switch between steam and hot water, the exhaust heat recovery section 2 is used for a plurality of heat exchanges between the upper header 34 and the lower header 35. A multi-tube once-through heat recovery body 40 connected by a pipe 36, an exhaust gas inlet side duct 31 connected to the inlet side of the heat recovery body 40, an economizer 8 connected to the outlet side of the heat recovery body 40, and an exhaust gas outlet side duct 32 And the warm water generating section 3 of the body 37, the heat exchange pipe 14 for hot water provided in the body 37, the steam extraction valve 9 communicating with the body 37, and the heat exchange pipe 14 for hot water. Hot water supply valve 11 and hot water litter communicating with both ends By forming each from the valve 12, the body 37 and the upper header 34 are connected via a large diameter main communication pipe 27, and the body 37 and the lower header 35 are connected via a communication pipe 28. The exhaust heat recovery unit 2 and the hot water generation unit 3 are integrated, and an automatic bleeder 33 is provided in the body 37 of the hot water generation unit 3. When hot water is generated, the multi-pipe once-through heat recovery body 40 and the body 37 are provided. The inside is at atmospheric pressure or lower, the water level of the heat transfer water Wo is held inside the upper header 34, and the main water supply valve 38 is held in a closed state .

The invention of claim 3 is the invention of claim 1 or 2, wherein the received high-temperature exhaust gas G is used as turbine exhaust gas from the micro gas turbine power generator, and the generated steam is contained in the driving gas for the micro gas turbine. It is set as the structure which injects into .

According to a fourth aspect of the present invention, in the first or second aspect of the present invention, the auxiliary burner portion 5 for heating the exhaust gas G is interposed in the exhaust gas inlet side duct 31 .

In the present invention, the exhaust heat recovery section 2 that generates steam and the hot water generation section 3 are integrally formed so that the generation of steam and the generation of hot water can be switched.
As a result, compared to the conventional case of providing two types of cans, a waste heat boiler for generating steam and a heat exchanger for generating hot water, not only can the manufacturing cost of the device be greatly reduced, The heat recovery efficiency can be further increased.

  In addition, when the micro gas turbine power generator and the present invention are used in combination, it is possible to prevent a decrease in the output of the turbine generator in the summer by using the generated steam, and to meet the demand for hot water that increases in the winter. Can also respond smoothly.

  Further, when the hot water generating unit 3 is a vacuum type hot water generating unit, not only the hot water can be supplied more efficiently, but also the inside of the heat recovery body 40 and the body part 37 are airtight after the steam generation is stopped. The internal pressure is reduced as the both parts 40 and 37 are naturally cooled, which is very convenient.

Hereinafter, an embodiment of a hot water / steam combined heat exchanger according to the present invention will be described based on the drawings.
FIG. 1 is a perspective view of a hot water / steam combined heat exchanger according to the present invention, and FIG. 2 is a system diagram showing the overall configuration of the hot water / steam combined heat exchanger.
3 is a schematic diagram of the II view of FIG. 1, and FIG. 4 is a schematic diagram of the Loro view of FIG.

1 to 4, 1 is a hot water / steam combined heat exchanger, 2 is an exhaust heat recovery unit, 3 is a hot water generation unit, 4 is a water supply unit unit, 5 is an auxiliary burner unit, 6a is an exhaust gas inlet, and 6b is Exhaust gas outlet, 7 is a fuel control valve, 8 is an economizer, 9 is a steam extraction valve, 10 is a steam flow control valve, 11 is a hot water supply valve, 12 is a hot water return valve, 13 is a three-way switching valve, and 14 is heat exchange for hot water Tube, 15 is a temperature detector, 16 is a pressure detector, 17 is a pressure controller, 18 is a temperature controller, 19 is a hot water circulation pump, 20 is a mist separator, 21 is a softener, 22 is a water supply tank, and 23 is a drug injection device (Cleaning can), 24 is a water supply pump, 25 is a blower, 26 is a control box, 27 is a main communication pipe, 28 is a communication pipe, 29 is a base, 30 is caging, 31 is an inlet duct, 32 is an outlet side duct 33 is an automatic bleeder, 34 is an upper header, 35 is a lower header, 36 is a heat exchange pipe, 37 is a trunk, 38 is a main water supply valve, 39 is a blow valve, 40 is a multi-tube once-through heat recovery body, 41 is Sealed expansion tank (or safety valve), G is exhaust gas, F is fuel gas (city gas), HW ₁ is high temperature hot water, HW ₂ is low temperature hot water, S is steam, W is raw water (clean water), Wo is a heat medium It is water.

  As shown in FIG. 1, the hot water / steam combined heat exchanger 1 is mainly composed of an exhaust heat recovery unit 2, a hot water generation unit 3, a water supply unit 4 to the exhaust heat recovery unit 2, an auxiliary burner unit 5, and the like. It is configured.

  As shown in FIGS. 3 and 4, the exhaust heat recovery unit 2 connects the upper header 34 and the lower header 35 with a large number of heat exchange tubes 36, so-called multi-tube flow-through heat recovery main body 40. The exhaust gas inlet is provided on the inlet side, and the exhaust gas outlet is provided on the outlet side. Further, the outer surface of the main body 40 is protected by the caging 30 through a heat insulating material.

The hot water generating unit 3 is formed of a cylindrical body 37, a heat exchange pipe 14 disposed therein, an automatic bleeder 33 for exhausting the body 37, and the like, and the exhaust heat recovery unit 2 It is arranged and fixed at an upper position.
As will be described later, the cylindrical body portion 37 functions as a so-called air-water separator when steam is generated, and functions as a so-called vacuum evaporation chamber when hot water is generated.
Further, the automatic bleeder 33 is formed mainly with a bleed pump or the like.

  The exhaust heat recovery unit 2 and the hot water generation unit 3 are connected between the upper header 34 and the body portion 37 by a main connection pipe 27 having a large diameter (100A in this embodiment) and by a connection pipe (50A in this embodiment) 28. The lower header 35 and the body 37 are connected to each other by being connected to each other. As will be described later, the heat exchange pipe 36, the upper and lower headers 34 and 35 of the exhaust heat recovery unit 2 from the water supply unit 4 and the body The heat transfer water Wo injected into the bottom part of the part 37 circulates and flows between the heat recovery body 40 of the exhaust heat recovery part 2 and the body part 37 of the hot water generation part 3.

In the present embodiment, the heat transfer area of the heat recovery body 40 of the exhaust heat recovery unit 2 is suppressed to 5 m ² or less so as to have a structure belonging to the category of so-called simple boilers. Of course, the heat transfer area may be increased.

The water supply unit 4 includes a softener 21, a water supply tank 22, a chemical injection device 23, a water supply pump 24, a blow tank 25, and the like, and a heat exchange pipe that forms a heat recovery main body 40 of the exhaust heat recovery unit 2. Generation of scales and the like in 36 etc. is effectively prevented.
In addition, since the structure of the water supply unit part 4 for this kind multi-tube once-through boiler is well-known, the detailed description is abbreviate | omitted here.

The auxiliary burner unit 5 includes a fuel control valve 7, a gas burner (not shown), and the like. When the amount of heat of the exhaust gas Gh is insufficient, the auxiliary burner unit 5 is operated to operate the exhaust heat recovery unit 2. Increase heat recovery.
In the present embodiment, the auxiliary burner portion 5 that uses city gas (13A) F as fuel is interposed in the inlet duct 31. However, it goes without saying that the auxiliary burner portion may be omitted. .

With reference to FIG. 1 thru | or FIG. 4, the hot-water / steam combined type heat exchanger 1 which concerns on a present Example was manufactured for the purpose of the heat recovery of the turbine exhaust gas from the gas turbine power generator for 60 kw, The horizontal width and vertical width of the base 29 are each selected to be about 1200 mm.
Further, the horizontal width (longitudinal direction) of the exhaust heat recovery unit 2 is about 1200 mm, and the horizontal width between the outer wall of the inlet side duct 31 and the outer wall of the outlet side duct 32 is selected to be about 1650 mm.
Further, the vertical width dimension of the exhaust heat recovery unit 2 is selected to be about 530 mm.
In addition, the dimension in the height direction is selected to be about 1700 mm between the lower surface of the base 29 and the upper surface of the body portion 37 of the hot water generating unit 3. In addition, the outer diameter of the trunk | drum of the said warm water generation | occurrence | production part 3 is 320 mmphi, and length is 650 mm.

Next, the operation of the hot water / steam combined heat exchanger 1 according to the present invention will be described.
The hot water / steam combined heat exchanger is usually installed in the vicinity of a high temperature exhaust gas emission source such as a micro gas turbine power generation device, and receives the high temperature exhaust gas G discharged from the power generation device or the like into the exhaust gas inlet 6a.

When the demand for hot water in summer or the like decreases and steam injection to the micro gas turbine is required, the hot water / steam combined heat exchanger 1 is operated as an exhaust heat boiler.
That is, when steam S is generated, first, an operation changeover switch (not shown) provided in the control box 26 is set to the boiler operation side. Thereby, the warm water supply valve 11 and the warm water return valve 12 of the warm water generator 3 are automatically closed, and the warm water supply system is completely excluded. In addition, the steam supply system including the steam extraction valve 9 and the water supply unit 4 are automatically set to the operating state.
Further, the auxiliary burner unit 5 is also set in an operable state according to the steam load, and the automatic bleeder 33 of the hot water generating unit 3 is also automatically excluded from the system.

Exhaust gas G from the high-temperature turbine supplied from the exhaust gas inlet 6a through the inlet duct 31 to the gas inlet side of the multi-tube flow-through heat recovery body 40 is in contact with the heat exchange pipe 36 and is economized from the exhaust gas outlet. 8 and the outlet side duct 32 are discharged into the atmosphere.
Further, due to the contact with the heat exchange pipe 36, the heat of the exhaust gas G is transferred to the heat transfer water Wo inside the heat exchange pipe 36, and the heat transfer water Wo is heated and evaporated.

Steam and water heated and evaporated in the heat exchange pipe 36 are introduced into the body 37 of the hot water generator 3 through the large-diameter main connection 27, where air-water separation is performed. The separated heat transfer water Wo is returned to the lower header 35 through the communication pipe 28. Further, the steam S is supplied to a steam load (for example, injection into compressed air of a micro gas turbine) through a steam extraction valve 9 and a steam flow control valve 10.
Further, when the amount of heat of the exhaust gas G from the turbine is insufficient, the auxiliary burner unit 5 is appropriately operated.

On the other hand, when the hot water load increases in winter and the like, and the steam injection to the micro gas turbine or the like is not required, the hot water / steam combined heat exchanger 1 is operated as a hot water generator.
That is, by setting the operation changeover switch of the control box 26 to the hot water generation side, the steam extraction valve 9 provided in the body portion 37 of the hot water generation unit 3 is automatically closed, and the steam supply system is automatically excluded. The main water supply valve 38 of the water supply unit 4 and the blow valve 39 of the blow tank 25 are also automatically closed, and the system of the water supply unit 4 and the blow tank 25 is excluded from the exhaust heat recovery unit 2.

  In addition, the automatic bleeder 33 of the hot water generating unit 3 is maintained in an operating state, the hot water supply valve 11 and the hot water return valve 12 are opened, and the hot water load system is connected to the hot water generating unit 3.

  After the steam generation state is switched to the warm water generation state, when the body portion 37 and the like of the hot water generation unit 3 are naturally cooled, the inside of the body portion 37 is naturally decompressed. Further, when the degree of decompression does not reach the set value, the automatic bleeder 33 is activated, and the inside of the trunk portion 37 is maintained at a predetermined degree of vacuum.

When the heat transfer water Wo in the heat exchange pipe 36 is heated by the heat of the exhaust gas G from the turbine, the heat transfer water Wo immediately boils in the upper header 34 and steam corresponding to the temperature of the heat transfer water Wo at that time. Generate pressure steam.
Further, the steam generated by the evaporation of the heat transfer water Wo is aggregated by being cooled by exchanging heat with the low-temperature hot water HW ₂ in the hot water heat exchange pipe 14 disposed in the body portion 37, thereby being dropped. And drops onto the bottom surface of the body portion 37.
The water surface of the heat transfer water Wo is set so as to be positioned near the upper surface of the upper header 34 of the exhaust heat recovery unit 2 during operation.

The micro gas turbine power generator (revolution: 96000 rpm) was operated under the operating conditions of the generated power of the turbine generator 60 kw and the heat input 214 kw by city gas (13A).
At this time, the temperature of the exhaust gas G from the gas turbine was about 290 ° C., and the flow rate was about 1500 Nm ³ / h.

When the hot water generating unit 3 was operated under the above conditions, the low temperature water HW ₂ of about 60 ° C. could be taken out at a rate of 10,000 kg / h (heat output 116 kw) as the high temperature water HW of about 70 ° C. . At this time, the temperature of the exhaust gas G discharged from the outlet side duct 32 to the outside was about 90 ° C.

  When the exhaust heat recovery unit 2 is operated, the amount of steam generated from the body 37 is 89.1 kg / h, the enthalpy 661 kcal / kg of the saturated steam S, the exhaust gas Gh is discharged at about 150 ° C., and the steam pressure is 0. 0.7 to 0.8 MPa. Of course, when it is necessary to generate a larger amount of steam, the auxiliary burner unit 5 is operated.

Furthermore, the CO ₂ in the exhaust gas Gh when the hot water was generated was about 1.5%, CO was 5 to 10 ppm, NOx was about 5 to 9 ppm (converted to 0% O ₂ ), and hydrocarbons were about 0%.

When the exhaust heat recovery unit 2 is operated and the generated steam S is injected into the gas turbine power generator (intake amount 1500 kg / h, injection steam amount 89.1 kg / h, injection steam ratio 5.8%), the intake air temperature is Under the condition of 30 to 32 ° C., an increase in generated power of about 14 to 15% (8.4 to 9.0 kw) was obtained.
Further, the NOx concentration in the exhaust gas Gh at this time decreased from about 5 ppm to about 1.5 ppm. Hydrocarbons and CO ₂ remained almost unchanged. Although CO showed a tendency to increase slightly, it was found that the level was not particularly problematic.

  In the above-described embodiment, the case where the hot water / steam combined heat exchanger 1 according to the present invention is applied to a small micro gas turbine power generator has been described. However, the hot water / steam combined heat exchanger 1 according to the present invention includes: The present invention can be applied to any device or apparatus that discharges high-temperature exhaust gas G.

1 is a perspective view of a hot water / steam combined heat exchanger according to the present invention. It is a systematic diagram which shows the structure of a hot water / steam combined heat exchanger. FIG. 2 is a schematic diagram illustrating the view of FIG. FIG. 2 is a schematic view of a view in FIG. It is a systematic diagram of the heat and electricity supply equipment provided with the conventional micro gas turbine power generator. It is a systematic diagram of the other heat and electricity supply equipment provided with the conventional micro gas turbine power generator. It is a curve which shows the power generation output characteristic in a micro gas turbine power generator, and the increase characteristic of the generator output by steam injection.

Explanation of symbols

Ah is compressed air Gh is combustion gas G is exhaust gas F is fuel gas (city gas)
Wo is heat transfer water HW ₁ is high temperature hot water HW ₂ is low temperature hot water S is steam W is raw water (clean water)
V is a valve Ch is a check valve ST is a strainer P is a pump L is a flow meter TG is a thermometer PG is a pressure gauge SV is a safety valve 1 is a hot water / steam combined heat exchanger 2 is an exhaust heat recovery unit 3 is a hot water generator 4 The water supply unit 5 is the auxiliary burner 6a is the exhaust gas inlet 6b is the exhaust gas outlet 7 is the fuel control valve 8 is the economizer 9 is the steam outlet valve 10 is the steam flow control valve 11 is the hot water supply valve 12 is the hot water return valve 13 is three-way switching The valve 14 is a hot water heat exchange pipe 15 is a temperature detector 16 is a pressure detector 17 is a pressure controller 18 is a temperature controller 19 is a hot water circulation pump 20 is a mist separator 21 is a softener 22 is a water supply tank 23 is a chemical injection device (cleaning device) Cans)
24 is a water supply pump 25 is a blow device 26 is a control box 27 is a main communication pipe 28 is a communication pipe 29 is a base 30 is a caging 31 is an inlet duct 32 is an outlet duct 33 is an automatic bleeder 34 is an upper header 35 is a lower header Reference numeral 36 denotes a heat exchange pipe 37, a body part 38, a main water supply valve 39, a blow valve 40, a multi-tube once-through heat recovery body 41, a sealed expansion tank (or safety valve)

Claims (4)

Exhaust heat recovery unit (2) of exhaust gas (G), hot water generation unit (3) integrated with the exhaust heat recovery unit (2), heat to the exhaust heat recovery unit (2) and the hot water generation unit (3) And a water supply unit (4) for supplying water (Wo), wherein the exhaust heat recovery unit (2) is an upper header. (34) and the lower header (35) are connected to the inlet side of the heat recovery body (40) by a multi-tube once-through heat recovery body (40) connected by a plurality of heat exchange pipes (36). (31), the economizer (8) connected to the outlet side of the heat recovery body (40), and the exhaust gas outlet side duct (32), and the warm water generating part (3) is connected to the trunk part (37) and the trunk part. (37) Steam extraction for communicating with the heat exchange pipe (14) for hot water provided in the body (37) Hot water supply valve communicating with the end portions (9) and the hot water heat exchanger tubes (14) (11) and hot water return valve (12) because to each form, the body portion (37) and the upper header (34) during through the main communicating pipe of large diameter (27), and also body portion (37) and a lower header (35) communicating pipe between (28) Lehigh heat recovery unit by to each linked via a (2 ) And the hot water generating part (3), and the body (37) of the hot water generating part (3) is used as a steam-water separator when steam is generated. Combined heat exchanger. Exhaust heat recovery unit (2) of exhaust gas (G), hot water generation unit (3) integrated with the exhaust heat recovery unit (2), heat to the exhaust heat recovery unit (2) and the hot water generation unit (3) And a water supply unit (4) for supplying water (Wo), wherein the exhaust heat recovery unit (2) is an upper header. (34) and the lower header (35) are connected to the inlet side of the heat recovery body (40) by a multi-tube once-through heat recovery body (40) connected by a plurality of heat exchange pipes (36). (31) and the economizer (8) connected to the outlet side of the heat recovery main body (40) and the exhaust gas outlet side duct (32), and the warm water generating part (3) is connected to the trunk part (37) and the trunk part. (37) Steam extraction for communicating with the heat exchange pipe (14) for hot water provided in the body (37) (9) and a hot water supply valve (11) and a hot water return valve (12) communicating with both ends of the hot water heat exchange pipe (14), respectively, and the body (37) and the upper header (34) The exhaust heat recovery section (2) is connected by connecting the main pipe (27) with a large diameter between them and the trunk section (37) and the lower header (35) via a communication pipe (28). The hot water generator (3) is integrated and an automatic bleeder (33) is provided in the body (37) of the hot water generator (3). When hot water is generated, a multi-tube once-through heat recovery body (40) is provided. The body (37) is kept at atmospheric pressure or lower, the water level of the heat transfer water (Wo) is kept inside the upper header (34), and the main water supply valve (38) is kept closed. Features a heat / steam combined heat exchanger. The high-temperature exhaust gas (G) to be received is used as turbine exhaust gas from the micro gas turbine power generator, and the generated steam is injected into the driving gas for the micro gas turbine. Hot water / steam combined heat exchanger. The hot water / steam combined heat exchanger according to claim 1 or 2, wherein an auxiliary burner portion (5) for heating the exhaust gas (G) is interposed in the exhaust gas inlet side duct (31) .

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