JP3882107B2 - Gas turbine built-in boiler - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gas turbine built-in boiler combining a small boiler and a small gas turbine used for business use, small-scale industry, and the like, and a cogeneration system using the same.
[0002]
The gas turbine built-in boiler of the present invention enables energy saving and electric output extraction of a small boiler used for business use, small-scale industry, and the like.
[0003]
[Prior art]
Conventionally, small once-through boilers and flue-tube flue boilers are used in air-conditioning, commercial, and small-scale industrial processes by utilizing the latent heat of condensation of the low-pressure (about 0.7 MPa) saturated steam that is generated.
[0004]
In such applications, electric power is often used at the same time, so in relatively large facilities, cogeneration is installed, generating electricity with a reciprocating engine or gas turbine, and heating the boiler with the waste heat. I get steam.
[0005]
However, in such conventional cogeneration, the temperature of the jacket water is low in the case of a reciprocating engine, and the steam boiler cannot be operated, and in the case of a gas turbine, it is large in the case of a simple cycle. The power generation efficiency cannot be maintained high unless the scale (several thousand kW or more) is used.
[0006]
Recently, so-called micro gas turbines having an output of less than 300 kW and using a centrifugal type for a compressor and an expansion turbine have come into practical use. Many micro gas turbines use a regeneration cycle, and even with a low pressure ratio (about 4), it is possible to obtain power generation efficiency (about 30%) equivalent to a gas turbine of several thousand kW class (about 15 pressure ratio). is there.
[0007]
However, in the micro gas turbine, the allowable temperature at the inlet of the expansion turbine (about 900 ° C .; hereinafter, this temperature may be described as “TIT”) is limited, and the exhaust gas temperature is low (about 250 ° C.). There is an inconvenience above. The former is because the air cooling structure of the metal blades cannot be taken because of the small size or the radiation structure, and the latter is because the waste heat is used for preheating the combustion air by adopting a regeneration cycle. Therefore, in order to suppress the temperature at the inlet of the expansion turbine, in these micro gas turbines, excess air is compressed by a compressor and injected into the combustor, and the combustion gas is diluted and cooled together with cooling of the combustor.
[0008]
Examples of means for returning the steam generated from the waste heat boiler to the combustor or expansion turbine of the gas turbine and increasing the shaft output of the turbine (two fluid cycle) include a chain cycle and a flex cycle. The former is for blowing superheated steam, and the latter is for blowing a mixed gas of saturated steam and compressor outlet air. In both cases, saturated steam injection is avoided to prevent erosion of the turbine blades.
[0009]
In addition, since a large amount of steam is injected, there are problems such as securing and cost of boiler water and its raw water, and generation of white smoke when releasing steam saturated exhaust gas.
[0010]
Gas turbine exhaust gas having a high residual oxygen concentration (around 15%) can save energy when the auxiliary fuel is combusted using oxygen in the exhaust gas as an oxidant rather than burning with fresh air. This is because the amount of heat for heating the fresh air becomes unnecessary, and this is the energy saving principle of a so-called exhaust refire boiler.
[0011]
However, the use of the exhaust gas reburning technique also requires a special structure that does not blow off the burner even during low-oxygen combustion.
[0012]
[Problems to be solved by the invention]
Thus, the conventional cogeneration is not efficient in terms of energy and economy unless it is a large-scale facility, and there are various restrictions on the use of waste heat and steam.
[0013]
Accordingly, an object of the present invention is to provide an improved technique for conventional cogeneration. Specifically, the main object is to solve the following problems in a small cogeneration system with a power generation output of less than 300 kW by integrating a small gas turbine and a small boiler.
(1) Even in a small cogeneration system, waste heat is effectively recovered as steam while maintaining the power generation output equivalent to that of the medium size.
(2) Further increase the electrical output using steam.
(3) Ensure stable performance that does not depend on site construction technology.
(4) Provide a cogeneration system that is small, light and inexpensive.
(5) Suppress the increase in boiler water usage associated with the adoption of a two-fluid cycle.
(6) Noise, nitrogen oxides (NO _X ) To prevent or suppress the emission of white smoke.
[0014]
[Means for Solving the Problems]
[Configuration 1]
A gas turbine built-in boiler according to the present invention is a boiler having a boiler structure of a small once-through type or a flue-tube type using an exhaust gas of a small gas turbine using a regeneration cycle as a heat source, as described in claim 1.
・ Gas turbine exhaust gas is led directly to the combustion gas introduction chamber of the boiler without going through the flue,
・ Saturated steam is generated using the heat stored in the exhaust gas
This is a boiler with a built-in gas turbine.
[0015]
Here, the combustion gas introduction chamber is a heat exchange chamber corresponding to a combustion chamber in a boiler for burning ordinary fuel. Usually, the combustion chamber of the boiler can be used as it is, but because the temperature of the combustion exhaust gas is low and the combustion space is unnecessary, heat transfer promotion fins are installed on the combustion chamber surface, and heat transfer tubes are added. Heat transfer area increasing means may be used in combination. Further, all or part of the gas turbine may be installed in the combustion gas introduction chamber.
[0016]
[Function and effect]
If the exhaust gas of the small gas turbine using the regeneration cycle is directly led to the combustion gas introduction chamber of the boiler without passing through the flue as in this configuration, all the heat stored in the exhaust gas can be led to the boiler without lowering the temperature. Furthermore, since the heat insulation flue work at the installation site can be omitted, a cogeneration system can be configured at low cost while ensuring reliability.
[0017]
The exhaust gas temperature of the small gas turbine using the regeneration cycle is about 250 ° C., and the temperature of the saturated water vapor of 0.7 MPa is about 165 ° C. Therefore, in order to effectively recover the exhaust gas retained heat, the flue that causes heat dissipation loss It is extremely important to reduce such facilities. Further, since the temperature difference is small, it is necessary to configure the boiler with a large heat transfer area in order to ensure the boiler output.
[0018]
However, when the heating gas is combustion exhaust gas, the combustion chamber is unnecessary, so that the space can be used as a space for increasing the heat transfer area. With a small once-through boiler, the heat transfer area can be expanded by increasing the number of heat transfer tubes, and with a furnace tube smoke tube boiler, heat transfer fins can be installed on the inner surface of the furnace tube. The increase in the heat transfer area by these means is advantageous because it does not increase the external dimensions of the boiler.
[0019]
The micro gas turbine is generally small and light, and can be easily attached integrally to a small once-through boiler or a flue tube boiler. Further, if all or part of the gas turbine is installed so as to be immersed in the combustion gas introduction chamber, the whole can be made compact.
[0020]
If the gas turbine built-in boiler is integrally surrounded by the casing, the sound insulation of both can be effectively performed by devising the casing structure. In particular, when the noise generating part of the gas turbine is installed in the combustion gas introduction chamber, the boiler wall can also be used as a sound insulation wall, which is more effective for sound insulation.
[0021]
[Configuration 2]
A gas turbine built-in boiler according to the present invention is a boiler having a small once-through boiler structure that uses exhaust gas from a small gas turbine using a regeneration cycle as a heat source, as described in claim 2.
・ Gas turbine exhaust gas is led directly to the combustion gas introduction chamber of the boiler without going through the flue,
・ After heating the boiler feed water using the heat stored in the exhaust gas,
-Further heating the boiler feedwater upstream of the expansion turbine using a portion of the combustion gas holding heat of the gas turbine combustor,
・ Saturated steam is generated by separating the obtained brackish water two-phase flow with a gas-liquid separator
This is a boiler with a built-in gas turbine.
[0022]
Here, the gas-liquid separator usually corresponds to a steam drum in a boiler.
[0023]
[Function and effect]
In the case of the configuration 1, since the exhaust gas temperature of the regeneration cycle gas turbine is low, a large heat transfer area is required to recover the waste heat. Further, in the case of a micro gas turbine, there is a restriction that the temperature of the combustion gas must be lowered to the allowable inlet temperature (TIT; usually about 900 ° C.) due to the material restriction of the expansion turbine. Therefore, when a gas turbine is used, the combustion gas is usually cooled to this temperature (TIT) by dilution cooling with compressed air obtained by a compressor.
[0024]
By the way, in the case of a gas turbine, the power required to produce compressed air is recovered by an expansion turbine, and the recovery rate is determined by the product of the heat insulation efficiency of the compressor and the expansion turbine. In the case of a small gas turbine, each efficiency is about 80%, so that about 30% of the diluted air compression power is lost even though it is recovered partially through heat.
[0025]
Therefore, if the temperature of the combustion gas is cooled to TIT using boiler water (or wet saturated steam) preheated with exhaust gas, cooling of the combustion gas and reduction of diluted air compression power can be achieved at the same time, and the efficiency of the gas turbine is improved. While improving, it can heat boiler water effectively and can improve the quantity (evaporation amount = boiler capability) and quality (high pressure, high dryness, overheating) of steam.
[0026]
The combustor can also be cooled by boiler water. In this case, since cooling is boiling heat transfer, cooling can be performed at a stable temperature and a small heat transfer area.
[0027]
[Configuration 3]
A gas turbine built-in boiler according to the present invention, as described in claim 3, is provided with an auxiliary burner directly downstream of a small gas turbine using a regeneration cycle and directly connected to a combustion gas inlet of the boiler,
-Using oxygen in the gas turbine exhaust as all or part of the oxidant used in the auxiliary burner,
・ Uses heat stored in gas turbine exhaust gas and combustion heat from auxiliary burner fuel as heat sources
It is a gas turbine built-in boiler given in composition 1 or 2 made into composition.
[0028]
[Function and effect]
With this configuration, the boiler can be operated by freely changing the load in an input range that is equal to or less than the rated sum of the gas turbine exhaust gas and the auxiliary burner heat regardless of the operation load of the gas turbine. This is convenient when the boiler is controlled in accordance with the operation load of the steam utilization facility.
[0029]
Moreover, since it is the operation as a so-called exhaust gas refired boiler, the amount of heat necessary for heating fresh air to the exhaust gas temperature is unnecessary, and energy is saved. The feature of the present invention is that, by integrating a micro gas turbine into a small boiler, an exhaust gas reburning burner with stable performance can be provided at a low cost by its mass production effect. In addition, it is possible to manufacture an exhaust gas reburning burner having a structure that takes in gas turbine exhaust gas in the least wasteful manner, and a wasteful exhaust gas duct can be omitted.
[0030]
[Configuration 4]
A gas turbine built-in boiler according to the present invention uses, as described in claim 4, all or part of the generated saturated steam for cooling a combustor or combustion gas of a small gas turbine,
-By blowing all or part of the superheated steam obtained as a result of the heat exchange into the combustor or expansion turbine of the gas turbine,
・ Increase shaft output of gas turbine
It is a gas turbine built-in boiler in any one of composition 1-3 set as composition.
[0031]
[Function and effect]
The steam obtained in the inventions according to configurations 1 to 4 is a low-pressure (about 0.7 MPa) saturated steam. Small boilers usually do not produce superheated steam because they do not have appropriate applications such as power generation. Therefore, a gas turbine combustor is cooled with saturated steam, and superheated steam generated as a result of heat exchange is blown into the combustor or expansion turbine, thereby forming a two-fluid gas turbine while suppressing erosion due to water droplets. And the shaft output of the gas turbine can be increased.
[0032]
Although the method of this structure is a kind of chain cycle, it differs from the chain cycle in that superheated steam is obtained by cooling the combustor or the combustion gas. Moreover, since the pressure ratio is about 4 in a small gas turbine (the pressure ratio is about 15 in a medium-sized or larger gas turbine), low-pressure steam can be used.
[0033]
Incidentally, if the steam pressure of the boiler is suppressed to the minimum pressure necessary for steam injection, the steam temperature is reduced (for example, the saturated steam temperature of 0.48 MPa is 150 ° C., so compared to 0.7 MPa steam). Therefore, the amount of heat recoverable from the gas turbine exhaust gas can be increased.
[0034]
Further, with this configuration, part or all of the compressed air for cooling the combustor and the cooling gas for the combustion gas becomes unnecessary, so that the amount of compressed air can be reduced. The effect is as described above. In the case of a micro gas turbine, a high-speed generator is usually used as a generator, and the generated power is converted into direct current by a converter and then converted into alternating current at a commercial frequency by an inverter. Can be selected regardless of frequency. Therefore, by changing the rotation speed of the gas turbine, the capacity of the compressor can be changed, and control for changing the amount of diluted air according to the amount of blown steam can be performed. Thereby, even if it changes the amount of blowing steam, TIT can be maintained below a fixed value or an upper limit.
[0035]
It is also possible to control the amount of compressed air by providing a damper or vane at the compressor inlet. Also by this, air compression power can be reduced and a gas turbine shaft output can be increased.
[0036]
With this configuration, the shaft output of the gas turbine can be changed efficiently, and cogeneration with a variable thermoelectric ratio can be provided. When the invention of configuration 3 is combined, a higher rate of change in thermoelectric ratio can be obtained.
[0037]
[Configuration 5]
The gas turbine built-in boiler according to the present invention, as described in claim 5, all or part of the generated saturated steam,
-By blowing into at least one place selected from the flame existing area in the combustor, the combustor part upstream of the flame existing area, the vicinity of the fuel nozzle and compressed air,
-Controlling the temperature of the combustion gas below the expansion turbine inlet allowable gas temperature (TIT),
・ Increase shaft output of gas turbine
It is a gas turbine built-in boiler in any one of composition 1-3 set as composition.
[0038]
[Function and effect]
In this configuration, the point where all or part of the low-pressure saturated steam is blown into the small gas turbine is different from the chain cycle or the flex cycle. In this configuration, the steam injection position is set to at least one location selected from the flame existence region in the combustor, the combustor portion upstream of the flame existence region, the vicinity of the fuel nozzle, and the compressed air, so that the high-temperature combustion gas To reduce the degree of saturation of the steam and obtain the same erosion suppressing effect as that of superheated steam injection. Also, the expansion turbine inlet allowable temperature (TIT) control is performed so as to be less than that by controlling the injection amount of steam.
[0039]
As a result, the above-described compressed air reduction effect can be obtained, and the gas turbine can be operated so as to obtain the largest electrical output by supplying a large amount of steam within a range where the gas turbine does not cause a surge.
[0040]
Even if the blown steam is dry and unfortunately erosion occurs in the expansion turbine, the micro gas turbine is inexpensive and easy to replace, so the damage amount is small, rather power generation efficiency is improved. The economic effect of increased power generation output is greater.
[0041]
In addition, the effect of suppressing nitrogen oxides (NOx) due to a drop in the flame temperature is also accompanied with the blowing of steam.
[0042]
[Configuration 6]
As described in claim 6, the gas turbine built-in boiler according to the present invention is provided with a condensing economizer at the exhaust gas outlet of the boiler,
・ Preheat boiler feedwater using heat recovered by economizer,
・ Condensate water separated and recovered from exhaust gas by economizer is reused as part of boiler feed water
It is a gas turbine built-in boiler in any one of composition 1-5 made into composition.
[0043]
[Function and effect]
In the present invention, the heat stored in the regenerative cycle gas turbine exhaust gas is used as the main heat source of the boiler, so that heat recovery from a large amount of low-temperature gas is possible. is there. Further, since the exhaust gas of the two-fluid gas turbine that performs steam injection contains a large amount of water vapor, the exhaust gas dew point is raised, so that the condensation latent heat of water vapor in the exhaust gas can be recovered at a relatively high temperature.
[0044]
The condensed water of the exhaust gas separated and recovered by the economizer contains a small amount of carbon dioxide, nitrogen oxide, sulfur oxide, etc. generated by combustion, but its concentration is further increased than that of ordinary combustion exhaust gas by blowing steam. Since it is decreasing, the corrosive environment is relatively mild.
[0045]
Therefore, by recovering a part of the large amount of boiler water consumed by the two-fluid gas turbine by the exhaust gas condensing economizer, the cost and amount of the raw water can be reduced. Thereby, although some expense is required for water treatment, such as neutralization of condensed water, cost can be suppressed as a whole and water resources can be saved.
[0046]
[Configuration 7]
The gas turbine built-in boiler according to the present invention is, as described in claim 7, exhaust gas obtained by separating a part of the contained water vapor as condensed water using a condensing economizer attached to the boiler,
・ By reheating the steam discharged from the boiler or a part of the recovered drain,
・ Prevent or suppress white smoke from exhaust gas emitted from chimneys
It is a gas turbine built-in boiler of the structure 6 made into the structure.
[0047]
[Function and effect]
Since the exhaust gas exiting the condensing economizer is saturated with water vapor, if it is directly discharged from the chimney, depending on the weather conditions, the water vapor may condense into water droplets and become white smoke that can be visually observed. In particular, white smoke tends to be generated in the winter when the temperature of the atmosphere is low or in the rainy season when the humidity is high. Although white smoke itself is not harmful, it is often necessary to prevent or suppress the whitening of water vapor since it is perceived as releasing harmful substances.
[0048]
In this configuration, the saturated exhaust gas discharged from the economizer is reheated with steam discharged from the boiler or part of the recovered drain, thereby reducing its humidity and preventing or suppressing white smoke. As a reheating method, for example, either indirect heating using a heat exchanger or direct heating by steam blowing is possible. The former is characterized by the fact that the amount of steam used is small and the amount of water vapor containing exhaust gas does not need to be increased, although it involves a heat exchanger installation cost.
[0049]
In order to prevent or suppress white smoke from the steam that was originally the waste heat of the gas turbine, or the drain after using the latent heat of vaporization, this configuration does not require new energy and is economical and economical There is.
[0050]
DETAILED DESCRIPTION OF THE INVENTION
A gas turbine built-in boiler according to the present invention will be described in detail with reference to the accompanying drawings.
[0051]
FIG. 1 is an external perspective view showing an embodiment of a gas turbine built-in boiler according to claim 1. In FIG. 1, the small gas turbine includes a centrifugal compressor 1, a radiant flow type expansion turbine 2, a combustor 3, a regenerator 4, a generator 5 and a duct 6, and an outlet of the regenerator 4 is a boiler 11. It is joined directly to the combustion gas introduction chamber of the (small once-through boiler) without going through the flue. An example of the small gas turbine is a micro gas turbine, and an operation method is preferably a regeneration cycle using a normal Brayton cycle.
[0052]
The gas turbine exhaust gas exiting the regenerator 4 enters the boiler 11 and exchanges heat with the boiler water in the heat transfer tube to generate saturated steam. As a result, the gas turbine built-in boiler generates two types of output, electricity and steam (heat). Electricity can be used independently or in system linkage with commercial power. Steam can be used for heating as well as for processes.
[0053]
In particular, when electricity is used independently and the generator 5 is a high-speed generator, DC power obtained by AC / DC conversion of the generated power by a converter can be directly used for the DC motor. In addition, if the consumer device converts it to an alternating current of an appropriate frequency, it is efficient because the loss accompanying the frequency conversion can be reduced. Examples of devices for which frequency conversion on the consumer device side is effective include fluorescent lamps, synchronous motors, and induction heating devices.
[0054]
The boiler 11 may be a furnace flue tube boiler. In this case, the micro gas turbine part is placed horizontally. Moreover, you may comprise so that all or one part of a gas turbine may intrude into a boiler combustion chamber. In this case, the gas turbine built-in boiler can be made compact, and the noise of the gas turbine can be shielded. Furthermore, if the micro gas turbine and the boiler 11 are surrounded by an integral casing, a soundproof enclosure can be effectively installed.
[0055]
Moreover, the heat exchange capability of the regenerator 4 of the gas turbine can be adjusted. If the gas turbine exhaust gas is diverted upstream of the regenerator 4 and combined with the regenerator passing exhaust gas after bypassing the regenerator 4, the regenerator heat exchange capacity is adjusted by adjusting the diversion ratio with a damper or the like. Can do. If the amount of heat exchange is reduced, the temperature of the exhaust gas supplied to the boiler rises, and the steam output of the boiler can be increased.
[0056]
FIG. 2 is a flowchart showing an embodiment of the gas turbine built-in boiler according to claim 2. The boiler water is pressurized by the feed water pump 13 and enters the boiler 11 and is heated by the exhaust gas exiting the regenerator 4 of the gas turbine, and further heated by the combustion gas in the gas turbine combustor 3 to become a brackish water two-phase flow. Then, it is separated into saturated steam and saturated water by a gas-liquid separator 17 (which usually corresponds to a steam drum of a boiler). The saturated steam is used as it is for the process and heating, and the saturated water is partially blown and then returned to the boiler by the feed water pump 13. Since the boiler water is heated in two stages of the boiler can and the heat exchanger of the gas turbine combustor 3, the boiler type is preferably a once-through type.
[0057]
In addition, although heating of the boiler water in the gas turbine combustor 3 is performed by installing a heat exchanger in that portion, it is convenient to perform the cooling of the combustor 3 as well. The combustion gas temperature must be cooled below the allowable temperature at the inlet of the expansion turbine (TIT), but there are two types of cooling means: a configuration with this heat exchanger and dilution cooling with compressed air from the compressor 1. There is. By increasing the cooling rate according to this configuration, the performance and efficiency of the gas turbine built-in boiler as a whole can be improved by reducing the compressor shaft power and increasing the amount of heat acquired by the boiler steam.
[0058]
FIG. 3 is an external perspective view showing an embodiment of the gas turbine built-in boiler according to claim 3. An auxiliary burner 12 for combusting auxiliary fuel is directly connected directly downstream of the regenerator 4 of the gas turbine, so that the temperature drop of the gas turbine exhaust gas can be minimized.
[0059]
In the auxiliary burner 12, the auxiliary fuel is burned with residual oxygen in the gas turbine exhaust gas. Since the auxiliary burner 12 is required to have low oxygen combustion performance, it is preferable that the auxiliary burner 12 has a flame holding performance and a diffusion combustion system with swirling.
[0060]
By introducing the auxiliary fuel, the steam generation amount of the boiler can be controlled within the range of the boiler rated output with the gas turbine waste heat amount as the minimum capacity independently of the operation load of the gas turbine.
[0061]
Moreover, this structure can be implemented in combination with the other structure in this invention. The entry and exit of steam in FIG. 3 represents one embodiment in combination with configuration 2.
[0062]
4 and 5 are flowcharts showing an embodiment of the gas turbine built-in boiler according to claim 4. Saturated steam generated in the boiler 11 is sent to the gas turbine combustor 3 to cool the combustor 3 and / or cool the combustion gas in the combustor to obtain superheated steam.
[0063]
All of the generated superheated steam is injected into the combustor 3 (FIG. 4), or a part thereof is injected into the inlet of the expansion turbine 2 (FIG. 5) to increase the shaft power of the gas turbine. Excess superheated steam is used for other processes as steam with high dryness. Exhaust gas re-burning with auxiliary fuel and saturated steam can be used together.
[0064]
FIG. 6 is a flowchart showing an embodiment of the gas turbine built-in boiler according to claim 5. Saturated steam generated in the boiler 11 is injected into the flame existence region of the gas turbine combustor 3 or upstream thereof. The saturated steam is heated by a flame or a high-temperature combustion gas, increases in dryness and enters the expansion turbine 2 to increase the gas turbine shaft output. The saturated steam injection position may be in the flame existence region or upstream thereof, and may be the compressor 1 outlet, the gas nozzle, or the vicinity thereof.
[0065]
Thereby, even if saturated steam is used, the two-fluid cycle can be operated normally without erosion. Even if the dryness of the saturated steam is extremely low and erosion occurs on the expansion turbine blades due to the water droplets, the expansion turbine of the micro gas turbine can be easily and inexpensively replaced.
[0066]
Further, since the combustion temperature of the flame can be lowered by blowing water vapor, it is also effective in reducing NOx emissions.
[0067]
FIG. 7 is a flowchart showing an embodiment of the gas turbine built-in boiler according to claim 6. A condensing economizer 14 is attached to the exhaust gas outlet of the boiler 11, and condensed water is recovered as part of boiler feed water by condensing water vapor in the exhaust gas. When the condensed water is reintroduced into the boiler, a water treatment device 15 may be provided as necessary to perform pH adjustment water softening treatment or pure water treatment.
[0068]
As the gas turbine fuel, a clean fuel with a low sulfur content such as natural gas, LPG, kerosene or the like is used. When steam injection is performed on a gas turbine, a large amount of water vapor is contained in the exhaust gas, so this method is effective for saving boiler raw water. Of course, the condensation latent heat of the exhaust gas is used for preheating boiler feedwater, so it is also effective as a low-temperature waste heat recovery means for the regeneration cycle gas turbine.
[0069]
FIG. 8 is a flowchart showing an embodiment of the gas turbine built-in boiler according to claim 7. When exhaust gas is cooled by the condensing economizer 14, the exhaust gas becomes saturated, and if discharged from the chimney as it is, it may become white smoke. Therefore, the exhaust gas exiting the condensation economizer 14 is reheated by the reheater 16 to be released from the saturated state, thereby preventing or suppressing whitening of the exhaust gas when the exhaust gas is diffused into the atmosphere from the chimney.
[0070]
Saturated steam from the boiler is used as the heat source for reheating. Since it is steam originally generated by waste heat recovery of gas turbine exhaust gas, no new energy is required. In addition, it is also possible to use the retained sensible heat of drain water (saturated water recovered after consuming the latent heat of steam) recovered from the process or heating as another heat source.
[0071]
FIG. 9 is a flowchart showing an embodiment of cogeneration to which a conventional chain cycle is applied. The steam blown into the combustor 3 or the expansion turbine 2 is superheated steam.
[0072]
【The invention's effect】
The gas turbine built-in boiler according to the present invention has the following excellent effects.
(1) Even with a small-sized cogeneration system, the power generation output can be maintained at the same level as that of the medium size by adopting the regeneration cycle gas turbine.
(2) The low-temperature waste heat from the regeneration cycle gas turbine can be effectively recovered as saturated or superheated steam.
(3) The electric output can be further increased by performing the steam injection.
(4) The thermoelectric ratio can be changed by burning the auxiliary fuel.
(5) Stable performance independent of on-site construction skills can be secured.
(6) A cogeneration system can be provided in a small, light and inexpensive manner.
(7) Increase in boiler water consumption accompanying steam injection can be suppressed.
(8) Generation of noise, nitrogen oxides (NOx), white smoke, etc. can be prevented or suppressed.
[Brief description of the drawings]
1 is an external perspective view showing an embodiment of a gas turbine built-in boiler according to claim 1;
FIG. 2 is a flowchart showing an embodiment of a gas turbine built-in boiler according to claim 2;
3 is an external perspective view showing an embodiment of a gas turbine built-in boiler according to claim 3. FIG.
FIG. 4 is a flow chart showing an embodiment of a gas turbine built-in boiler according to claim 4.
FIG. 5 is a flowchart showing another embodiment of the gas turbine built-in boiler according to claim 4;
6 is a flow chart showing an embodiment of a gas turbine built-in boiler according to claim 5. FIG.
7 is a flow chart showing an embodiment of a gas turbine built-in boiler according to claim 6. FIG.
FIG. 8 is a flowchart showing an embodiment of a gas turbine built-in boiler according to claim 7;
FIG. 9 is a flowchart showing cogeneration to which a conventional gas turbine chain cycle is applied.
[Explanation of symbols]
1 Compressor
2 Expansion turbine
3 Combustors
4 Regenerator
5 Generator
6 Air duct
11 Boiler
12 Auxiliary burner
13 Water supply pump
14 Condensing economizer
15 Water treatment equipment
16 Reheater
17 Gas-liquid separator (steam drum)

Claims (6)

A boiler having a small once-through boiler structure that uses the exhaust gas of a small gas turbine using a regeneration cycle as a heat source,
・ By immersing all or part of the small gas turbine using the regeneration cycle into the combustion gas introduction chamber of the boiler, the gas turbine exhaust gas that has passed through the regenerator is directly burned without passing through the flue. Led to the gas introduction room,
・ After heating the boiler feed water using the heat stored in the exhaust gas,
-Further heating the boiler feedwater upstream of the expansion turbine using a portion of the combustion gas holding heat of the gas turbine combustor,
A gas turbine built-in boiler that generates saturated steam by separating the resulting brackish water two-phase flow with a gas-liquid separator. Provide an auxiliary burner directly downstream of the small gas turbine using the regeneration cycle,
-Using oxygen in the gas turbine exhaust as all or part of the oxidant used in the auxiliary burner,
Gas turbine built boiler according to the gas turbine exhaust gas potential heat and the auxiliary burner fuel combustion heat to claim 1, the heat source. Using all or part of the generated saturated steam to cool the combustor or combustion gas of a small gas turbine,
-By blowing all or part of the superheated steam obtained as a result of the heat exchange into the combustor or expansion turbine of the gas turbine,
The gas turbine built-in boiler according to claim 1 or 2 , wherein the shaft output of the gas turbine is increased. All or part of the generated saturated steam,
-By blowing into at least one place selected from the flame existing area in the combustor, the combustor part upstream of the flame existing area, the vicinity of the fuel nozzle and compressed air,
・ Control the temperature of the combustion gas below the allowable gas temperature at the inlet of the expansion turbine,
The gas turbine built-in boiler according to claim 1 or 2 , wherein the shaft output of the gas turbine is increased. A condensing economizer is attached to the exhaust gas outlet of the boiler.
・ Preheat boiler feedwater using heat recovered by economizer,
The gas turbine built-in boiler according to any one of claims 1 to 4 , wherein the condensed water separated and recovered from the exhaust gas by the economizer is reused as a part of boiler feed water. Exhaust gas separated from condensed water vapor as condensed water using a condensing economizer attached to the boiler,
-By reheating with steam discharged from the boiler or part of the recovered drain,
The gas turbine built-in boiler according to claim 5 , wherein the exhaust gas emitted from the chimney is prevented or suppressed from becoming white smoke.

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