JP5321340B2 - Steam injection gas turbine generator - Google Patents

Description

  The present invention relates to a steam injection gas turbine configured to inject steam generated by using exhaust heat of a gas turbine for driving a generator as a heat source to a combustor of the gas turbine to increase the output of the gas turbine. The present invention relates to a power generation device.

  As one of the methods of cogeneration power generation called so-called cogeneration system, the generator is driven by a gas turbine to generate electric power, and the combustion exhaust gas discharged from the gas turbine has a high temperature. Therefore, a technique is widely known in which the heat is recovered by an exhaust heat recovery boiler to generate steam, and this steam is supplied to a place where there is heat demand as process steam that can be used as a heat source.

  However, the balance between the amount of power and heat obtained when performing cogeneration as described above may not match the balance between the demand for power and the demand for heat. For example, the demand for power is the demand for heat. It is often larger than.

  For this reason, a steam injection gas turbine power generation device has been conventionally proposed as a device for enabling more electric power to be obtained by cogeneration.

  In the steam-injected gas turbine power generator, a compressor 2 and a turbine 3 are coaxially connected by a turbine shaft 4 and burned between the compressor 2 and the turbine 3 as schematically shown in FIG. An air (intake air) 6 taken in from the outside is compressed by the compressor 2, the compressed air 6 is guided to the combustor 5, and the combustor 5 uses a fuel supply device (not shown). Combustion of the fuel 7 supplied by the compressed air 6 generates a high-temperature and high-pressure combustion gas 8, and the combustion gas 8 is guided to the turbine 3 to be expanded to thereby expand the turbine 3. The output is extracted by driving, and a part of the extracted output is transmitted to the compressor 2 via the turbine shaft 4 and used as driving power, and the rest can be extracted as an external output. It comprises a gas turbine 1 which are to so that.

  A generator 9 is connected to the turbine shaft 4 of the gas turbine 1, and the generator 9 is driven by an external output of the gas turbine 1 to generate electric power.

  Further, an exhaust heat recovery boiler 11 is provided in the middle of the gas discharge line 10 for guiding the combustion exhaust gas 8a discharged after the combustion gas 8 is expanded by the turbine 3 of the gas turbine 1 and releasing it to the outside. The exhaust heat recovery boiler 11 recovers the exhaust heat of the combustion exhaust gas 8 a to generate steam 12, and a part of the generated steam 12 passes through the steam line 13 in the gas turbine 1. In addition to being injected into the combustor 5, the remainder of the steam 12 can be supplied as process steam through a process steam line 14 where there is a heat demand (not shown). Reference numeral 15 denotes water (soft water) supplied to the waste heat recovery boiler 11 (see, for example, Patent Document 1).

  According to the steam injection gas turbine power generator having such a configuration, the high-temperature and high-pressure steam 12 generated by using the heat remaining in the combustion exhaust gas 8a discharged from the gas turbine 1 by the exhaust heat recovery boiler 11 is Since the mass flow rate of the gas led from the combustor 5 to the turbine 3 can be increased by being guided through the line 13 and injected into the combustor 5 of the gas turbine 1, the output of the turbine 3 is increased. Thus, the power generation amount of the generator 9 can be increased and the power generation efficiency can be improved.

  By the way, in the steam injection gas turbine power generator, the steam 12 generated in the exhaust heat recovery boiler 11 is injected into the combustor 5 of the gas turbine 1 to increase the mass flow rate of the gas flowing through the turbine 3 and increase the output. However, if a certain amount of steam 12 is injected into the combustor 5, the flow rate of the compressor 2 decreases and surging occurs, so the actual amount of steam 12 that can be injected is limited. is there.

  For this purpose, various techniques have been proposed in the past for avoiding the surge limit even when the amount of steam 12 that can be injected into the combustor 5 of the gas turbine 1 in the steam-injected gas turbine power generator is increased. (For example, see Patent Document 1, Patent Document 2, Patent Document 3, Patent Document 4, and Patent Document 5).

  In the steam-injected gas turbine power generator, the steam generated in the exhaust heat recovery boiler (gas turbine exhaust gas boiler) using the exhaust heat of the combustion exhaust gas of the gas turbine is converted into volatile organic compounds such as toluene (hereinafter referred to as VOC). Conventionally proposed is a method of overheating using exhaust heat of combustion exhaust gas discharged from a VOC treatment deodorizing furnace for combustion treatment of exhaust gas containing gas and then injecting it into a combustor of a gas turbine (for example, And Patent Document 6).

JP 2000-213372 A Japanese Patent Laid-Open No. 11-229894 JP 2003-120332 A JP 2003-129860 A Japanese Patent No. 3664634 Japanese Patent No. 4186181

  However, since the temperature of the steam 12 generated in the exhaust heat recovery boiler 11 using the combustion exhaust gas 8a of the gas turbine 1 is normally as low as about 210 ° C., the steam 12 is used as the combustor of the gas turbine 1. The fact is that the energy brought into the turbine 3 on the downstream side of the combustor 5 is not so large even if it is injected into the turbine 5.

  Moreover, the combustion of the gas turbine 1 in the steam-injected gas turbine power generator while avoiding the surge limit by various methods shown in Patent Document 1, Patent Document 2, Patent Document 3, Patent Document 4, and Patent Document 5 described above. Even if the amount of the steam 12 that can be injected into the combustor 5 can be increased, the steam 12 generated in the exhaust heat recovery boiler 11 is about 210 ° C., and usually the combustion temperature in the combustor 5 that is about 1000 ° C. Therefore, if the injection amount of the steam 12 generated in the exhaust heat recovery boiler 11 to the combustor 5 of the gas turbine 1 increases, the temperature in the combustor 5 decreases, leading to misfire. The reality is that there are concerns.

  In Patent Document 6, the steam generated by the exhaust heat recovery boiler attached to the gas turbine of the steam injection gas turbine generator is used by utilizing the exhaust heat of the combustion exhaust gas discharged from the deodorizing furnace for VOC treatment. Although the idea of injecting into the gas turbine combustor after overheating has been shown, the superheat temperature of the steam is only about 350 ° C., which is significantly higher than the combustion temperature in the combustor of the gas turbine. In the low point, it is not much different from the temperature level of the steam generated in the exhaust heat recovery boiler. Therefore, even if the method described in Patent Document 6 is adopted, the energy that is brought into the turbine on the downstream side of the combustor of the gas turbine as described above does not increase so much. When the amount of steam injection increases, the temperature in the combustor decreases and this is insufficient as a countermeasure against the phenomenon of misfire.

  Moreover, since the deodorizing furnace for VOC treatment is essential in the one disclosed in Patent Document 6, it cannot be adopted when there is no VOC deodorizing furnace. Furthermore, the VOC treatment deodorization furnace has a problem that an external fuel is required as a supplementary fuel.

  Therefore, the present invention uses the combustion exhaust gas of the gas turbine to inject the steam generated in the exhaust heat recovery boiler into the combustor of the gas turbine without any external fuel. The energy brought into the turbine can be increased, fuel consumption in the combustor can be suppressed, and even if the amount of steam injection to the combustor of the gas turbine is increased, the combustor can be misfired. It is an object of the present invention to provide a steam-injected gas turbine power generator that can suppress the possibility of being connected.

  In order to solve the above-mentioned problem, the present invention comprises a compressor and a turbine that are coaxially connected to each other by a turbine shaft in accordance with claim 1 and uses air compressed by the compressor in a combustor. A gas turbine configured to extract the output by rotating the turbine shaft by expanding the high-temperature and high-pressure combustion gas generated by burning the fuel in the turbine; and a generator connected to the turbine shaft; An exhaust heat recovery boiler that recovers exhaust heat of combustion exhaust gas discharged from the gas turbine to generate steam, and steam for introducing the steam generated in the exhaust heat recovery boiler to the combustor of the gas turbine for injection In the steam-injected gas turbine power generator equipped with a line, a heat exchanger connected to a solar heat collector is provided in the middle of the steam line, and the steam guided to the steam line From overheating and configuration so as to be injected into the combustor of the gas turbine.

  Moreover, in the said structure, it is set as the structure which provided the heat exchanger connected to the solar thermal collector in multiple stages in the middle position of the steam line.

  Furthermore, in each of the above configurations, a heat exchange connected to the solar heat collector in the steam line is provided at a position upstream of the installation location of the heat exchanger connected to the solar heat collector in the steam line and connected to the solar heat collector in the steam line A temperature sensor is provided at a position downstream of the place where the heat exchanger is installed, and the steam flow rate adjusting valve is controlled according to the steam temperature detected by the temperature sensor after passing through the heat exchanger.

According to the steam injection gas turbine power generator of the present invention, the following excellent effects are exhibited.
(1) A compressor and a turbine are coaxially connected by a turbine shaft, and the high-temperature and high-pressure combustion gas generated by burning fuel in the combustor using the air compressed by the compressor is A gas turbine configured to extract the output by rotating the turbine shaft by being expanded by the turbine, a generator connected to the turbine shaft, and exhaust heat of the combustion exhaust gas discharged from the gas turbine to recover the steam In a steam-injection gas turbine power generator comprising a waste heat recovery boiler for generating steam and a steam line for directing and injecting steam generated in the exhaust heat recovery boiler to a combustor of the gas turbine, At the position, a heat exchanger connected to the solar heat collector is provided, and the steam guided to the steam line is superheated and then injected into the combustor of the gas turbine. As a result, the energy brought into the turbine downstream of the combustor by the gas turbine can be increased without requiring external fuel. Fuel consumption in the combustor when obtaining output can be suppressed.
(2) Furthermore, since the temperature difference between the temperature of the steam injected into the combustor of the gas turbine and the combustion temperature in the combustor can be reduced, even if the amount of steam injected into the combustor is increased, The risk of misfire due to a temperature drop in the combustor can be suppressed. Therefore, by combining with various methods for increasing the amount of steam that can be injected into the combustor of the gas turbine while avoiding the surge limit, it is possible to both avoid the surge limit and prevent misfire, In addition, a steam-injected gas turbine power generator that can achieve a significant reduction in fuel consumption can be realized.
(3) By setting the heat exchanger connected to the solar heat collector in multiple stages in the middle of the steam line, the temperature of the steam generated in the exhaust heat recovery boiler is changed to the combustor of the gas turbine. When heat is greatly heated so that the temperature difference from the internal combustion temperature becomes small, it is only necessary to gradually increase the temperature of the steam in each stage heat exchanger. And the outlet side temperature can be reduced. Therefore, it can be expected that the structure of each heat exchanger is prevented from becoming complicated as in the case where the heat exchanger has a structure capable of withstanding a large temperature difference between the inlet side temperature and the outlet side temperature.
(4) Location of the heat exchanger connected to the solar heat collector in the steam line provided with a steam flow rate adjusting valve upstream of the location of the heat exchanger connected to the solar heat collector in the steam line By providing a temperature sensor at a position downstream of the heat exchanger and controlling the steam flow rate adjusting valve in accordance with the steam temperature detected by the temperature sensor after passing through the heat exchanger, the weather, etc. When the amount of solar heat energy collected by the solar heat collector decreases due to the influence of the heat and the steam is not sufficiently heated by the heat exchanger, it should be overheated after passing through the heat exchanger by the temperature sensor. As the temperature drop of the steam is detected, the opening of the steam flow adjustment valve can be reduced, so a large amount of low-temperature steam that is not sufficiently heated is supplied to the combustor of the gas turbine. Possibility to be able to be prevented and that, combustor can be prevented the risk that misfire.

It is a schematic diagram showing one embodiment of a steam injection gas turbine power generator of the present invention. It is a figure which shows the outline of an example of the conventional steam injection gas turbine electric power generating apparatus.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 shows an embodiment of a steam-injected gas turbine power generator according to the present invention. Like the steam-injected gas turbine power generator shown in FIG. 2, a combustion exhaust gas 8a is produced from a gas turbine 1 that drives a generator 9. An exhaust heat recovery boiler 11 is provided in the middle of the gas exhaust line 10 for exhausting the gas, and a steam line 13 for guiding a part of the steam 12 generated by the exhaust heat recovery boiler 11 is connected to the combustor 5 of the gas turbine 1. In the configuration described above, a heat exchanger 17 connected to the solar heat collector 16 is provided in the middle of the steam line 13, and the steam 12 flowing through the steam line 13 is passed through the solar heat collector 17 by the heat exchanger 17. The superheated steam 12a can be injected into the combustor 5 of the gas turbine 1 after it is superheated by heat exchange with the solar heat collected by the heat device 16.

  More specifically, the solar heat collecting device 16 is configured such that, for example, the sunlight 18 primarily condensed using a primary condensing device (not shown) such as a number of flat mirrors (heliostats) for solar tracking is parabolic or combined. The solar heat energy is collected by the secondary condensing by the secondary concentrator 16a provided with an object surface, and the collected solar thermal energy is used as a heat exchange part with the steam 12 in the heat exchanger 17. It is assumed that the steam 12 supplied to the heat exchanger 17 can be overheated to about 800 ° C. by giving to (not shown).

  Furthermore, it is desirable that the heat exchanger 17 connected to the solar heat collecting device 16 be provided in multiple stages in the middle of the steam line 13 as shown in FIG. In the figure, the case where the heat exchanger 17 is provided in three stages is shown. With such a configuration, when the steam 12 of about 210 ° C. generated in the exhaust heat recovery boiler 11 is heated to about 800 ° C., the temperature of the steam 12 is gradually raised by the heat exchanger 17 in each stage. Thus, the temperature difference between the inlet side temperature and the outlet side temperature of each heat exchanger 17 can be reduced. Therefore, in general, when the heat exchanger has a structure that can withstand a large temperature difference between the inlet side temperature and the outlet side temperature, the design is difficult and the structure is considered to be complicated. The effect of preventing the structure of each heat exchanger 17 from becoming complicated can be expected by reducing the temperature difference between the side temperature and the outlet side temperature.

  By the way, when the amount of sunlight irradiated to each solar heat collector 16 decreases due to the influence of the weather or the like, the solar heat collected by each solar heat collector 16 and used to superheat the steam 12 by each heat exchanger 17. Therefore, it is conceivable that the temperature of the superheated steam 12a obtained from each heat exchanger 17 decreases. Furthermore, when the solar heat collecting device 16 is not irradiated with sunlight, the heat exchangers 17 cannot superheat the steam 12 flowing through the steam line 13. In view of this point, in the steam-injected gas turbine power generator according to the present invention, the steam flow adjustment valve 19 is provided in the steam line 13 at a position upstream of the installation location of each heat exchanger 17, and the steam line 13, a temperature sensor 20 is provided at a position downstream of the place where each of the heat exchangers 17 is installed, and a control command is sent to the steam flow rate adjusting valve 19 based on a temperature detection signal input from the temperature sensor 20. A temperature controller 21 is provided.

  Further, based on the temperature detection signal input from the temperature sensor 20, the temperature controller 21 is used for the superheated steam 12 a obtained after the steam 12 flowing through the steam line 13 passes through the heat exchangers 17. When a decrease in temperature is detected, the steam flow control valve 19 has a function of giving a control command for reducing the opening degree. Thereby, when the amount of solar heat energy collected by each solar heat collecting device 16 decreases and the temperature of the superheated steam 12a obtained after passing through each heat exchanger 17 decreases, the temperature controller 21 Since the opening degree of the steam flow rate adjusting valve 19 is reduced, the amount of steam 12 supplied to the heat exchangers 17 through the steam line 13 is reduced, and the amount of steam 12 that receives solar heat energy. To prevent a decrease in the superheated temperature of the steam 12, and a superheated steam 12a having a temperature lower than 800 ° C that is not sufficiently heated or 210 ° C that is not heated in each heat exchanger 17 It is possible to prevent the possibility that a large amount of the steam 12 as it is is supplied to the combustor 5 of the gas turbine 1 in advance.

  22 is a mist separator provided in the steam line 13 at a position immediately upstream of the place where each heat exchanger 17 is installed, and 23 is interposed between the turbine shaft 4 serving as the output shaft of the gas turbine 1 and the generator 9. It is a reduction gear.

  In addition, the same components as those shown in FIG.

  When the steam-injected gas turbine power generator of the present invention having the above configuration is used, when the fuel 7 is supplied to the combustor 5 of the gas turbine 1 and the gas turbine 1 is operated, the external output of the gas turbine 1 The generator 9 is driven to generate power.

  Further, when the combustion exhaust gas 8a discharged from the turbine 3 of the gas turbine 1 is guided to the exhaust heat recovery boiler 11 through the gas exhaust line 10, the exhaust heat recovery boiler 11 uses the heat held by the combustion exhaust gas 8a. Steam 12 is generated.

  A part of the steam 12 generated in the exhaust heat recovery boiler 11 is led to the combustor 5 of the gas turbine 1 through the steam line 13, and each heat exchanger 17 provided in the middle of the steam line 13. Is heated to about 800 ° C. by the heat exchange with the solar heat energy collected by the solar heat collecting device 16 connected to each heat exchanger 17, and the superheated steam 12 a is about 800 ° C. In this state, the fuel is injected into the combustor 5 of the gas turbine 1.

  Therefore, in the gas turbine 1, the temperature of the superheated steam 12a blown into the combustor 5 is significantly higher than the steam injected into the combustor of the gas turbine by the conventional steam injection gas turbine power generator. Even if the steam injection amount is the same, the external output of the gas turbine 1 is increased by increasing the energy brought into the turbine 3 on the downstream side of the combustor 5.

  Therefore, when the same external output as the gas turbine of the conventional steam injection gas turbine power generator is obtained as the external output of the gas turbine 1, the amount of fuel 7 used in the combustor 5 is reduced.

  Further, when the solar heat collector 16 is weakly irradiated or not irradiated, it is injected into the combustor 5 of the gas turbine 1 through the heat exchangers 17 provided in the middle of the steam line 13. The temperature of the heated superheated steam 12a decreases or the steam 12 that is not overheated is injected into the combustor 5 of the gas turbine 1. In this case, downstream of each heat exchanger 17 in the steam line 13 The temperature controller 21 detects the temperature drop of the superheated steam 12a after passing through the heat exchangers 17 by the temperature sensor 20 provided at the side position or the temperature of the steam 12 that is not overheated. The degree of opening of the steam flow rate adjusting valve 19 provided in the steam line 13 is automatically throttled, so that the superheated steam 12a that is not sufficiently heated or the steam 12 that is not overheated. , Be a large amount injected into the combustor 5 of the gas turbine 1 is automatically prevented. Therefore, the temperature drop in the combustor 5 of the gas turbine 1 is prevented in advance.

  Thus, according to the steam injection gas turbine power generator of the present invention, the solar heat collected by the solar heat collector 16 is generated by the exhaust heat recovery boiler 11 using the combustion exhaust gas 8a of the gas turbine 1. By heat exchange with energy, it is possible to inject into the combustor 5 of the gas turbine 1 after the temperature has been significantly increased to about 800 ° C. without requiring any external fuel. The energy brought into 3 can be increased, and the fuel consumption in the combustor 5 can be suppressed.

  Further, by setting the temperature of the superheated steam 12a supplied to the combustor 5 of the gas turbine 1 to about 800 ° C., the temperature difference from the combustion temperature (about 1000 ° C.) in the combustor 5 becomes small, so the gas turbine Even if the amount of steam injection to one combustor 5 is increased, the risk of misfire due to temperature drop in the combustor 5 can be suppressed. Therefore, injection to the combustor 5 of the gas turbine 1 while avoiding the surge limit of the compressor 2 as proposed in the conventional Patent Document 1, Patent Document 2, Patent Document 3, Patent Document 4, and Patent Document 5. It is possible to obtain an advantageous configuration when employing various methods for increasing the amount of steam 12 that can be used, thereby avoiding surge limits and preventing misfires, thereby reducing fuel consumption. A steam-injected gas turbine power generator that can achieve a significant reduction can be realized.

According to the numerical calculation performed by the present inventors on the steam-injected gas turbine power generator of the present invention configured as shown in FIG. 1, in the 2 MW class steam-injected gas turbine power generator, the combustor 5 of the gas turbine 1 is supplied to the combustor 5. When the steam injection amount is 2500 kg / hr, assuming that the incident heat flux of the sun is 860 W / m ² , which is an incident heat flux that can be achieved in Japan if it is fine weather, the temperature of the steam 12 is 207 ° C. to 800 ° C. If it is made to overheat, the fuel 7 can be saved by about 11.9%, and the conversion efficiency of solar light to electric power can be obtained as 13.7%, which is the same conversion efficiency as a solar cell. It has been.

  The present invention is not limited to the above embodiment, and is generated in the gas turbine 1 for driving the generator 9, the exhaust heat recovery boiler 11 for recovering the exhaust heat, and the exhaust heat recovery boiler 11. The gas turbine 1 and the exhaust heat recovery boiler 11 may be of any type as long as the steam line 13 for introducing and injecting the steam 12 to be introduced into the combustor 5 of the gas turbine 1 to be injected. The gas turbine 1 and the exhaust heat recovery boiler 11 may have any type of peripheral device configuration.

  The number provided on the steam line 13 of the heat exchanger 17 connected to the solar heat collector 16 may be appropriately changed or may be singular.

  As long as the solar heat collecting device 16 can give the heat exchanger 17 solar energy that can heat the steam 12 generated in the exhaust heat recovery boiler 11 to about 800 ° C., any solar heat collecting device 16 can be used. A solar heat collecting device 16 of a form may be adopted.

  Of course, various modifications can be made without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Gas turbine 2 Compressor 3 Turbine 4 Turbine shaft 5 Combustor 6 Air 7 Fuel 8 Combustion gas 8a Combustion exhaust gas 9 Generator 11 Exhaust heat recovery boiler 12 Steam 12a Superheated steam 13 Steam line 16 Solar heat collector 17 Heat exchanger 19 Steam flow control valve 20 Temperature sensor

Claims (3)

  A compressor and a turbine are coaxially connected by a turbine shaft, and high-temperature and high-pressure combustion gas generated by burning fuel in a combustor using air compressed by the compressor is expanded in the turbine. The gas turbine is configured to rotate the turbine shaft to take out the output, the generator connected to the turbine shaft, and the exhaust heat of the combustion exhaust gas discharged from the gas turbine to recover and generate steam In a steam-injection gas turbine power generator having an exhaust heat recovery boiler and a steam line for introducing and injecting steam generated in the exhaust heat recovery boiler to the combustor of the gas turbine, in the middle of the steam line, A heat exchanger connected to the solar heat collector is provided so that the steam guided to the steam line is superheated and then injected into the combustor of the gas turbine. Steam injection gas turbine power generation apparatus characterized by having the configurations.   The steam-injected gas turbine power generator according to claim 1, wherein heat exchangers connected to the solar heat collector are provided in multiple stages in the middle of the steam line.   A steam flow rate adjustment valve is provided upstream of the installation location of the heat exchanger connected to the solar heat collector in the steam line, and downstream of the installation location of the heat exchanger connected to the solar heat collection device in the steam line. The steam injection gas turbine according to claim 1 or 2, wherein a temperature sensor is provided at a side position, and the steam flow rate adjusting valve is controlled according to a steam temperature detected by the temperature sensor after passing through the heat exchanger. Power generation device.

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