JP4409566B2 - Lean premixed combustion system and control method thereof - Google Patents

Description

  The present invention relates to a lean premixed combustion apparatus capable of stably maintaining lean premixed combustion even when the load suddenly fluctuates, and to improve followability to load fluctuations in fuel supply amount, and a control method therefor It is.

In a gas turbine, strict environmental standards are provided with respect to the exhaust gas composition, in particular, NOx reduction of emissions (hereinafter, referred to as NO _X.) It is desired. As a means of low NO _X reduction, a method of reducing the combustion flame temperature by injecting water or steam into the combustion chamber has been adopted by the previous, in this way, the corrosion of the turbine due to a decrease or bad quality of the engine thermal efficiency There were various disadvantages such as a reduction in life. In recent years, as a means of reducing NO _X in a dry type without using water or steam, lean premixed combustion method is well known to be effective. In this lean premix combustion method, air and fuel are premixed and burned as a mixture with uniform fuel concentration, so there is no combustion region where the flame temperature is locally high, and the fuel is diluted. because it can totally reduce the flame temperature also makes it possible to effectively reduce NO _X generation amount.

However, in this lean premixed combustion system, there is little generation of NO _X, and the range of air-fuel ratio can be stably combusted at high combustion efficiency without occurrence of a misfire is extremely narrow. Therefore, if the air-fuel ratio is too high, incomplete combustion occurs and the combustion stability is remarkably reduced. Conversely, if the air-fuel ratio is too low, the fuel is excessively rich and NO _x produced increases exponentially. Therefore, in order to maintain at a low NO _X, and the high combustion efficiency in a wide load range of the gas turbine maintains the mixture ratio of air and fuel regardless operating conditions of the gas turbine (air) within a predetermined range Need to be controlled accurately.

  In order to maintain this air-fuel ratio within a certain range, the number of main premix burner operations is increased by turning on / off the plurality of main premix burners in response to an increase in load, and additional tracking is performed. 2. Description of the Related Art A gas turbine combustor that performs output control according to a load by continuously controlling the amount of fuel supplied to a burner according to a change in the load is known (see Patent Document 1). In addition, a method is also disclosed in which the air-fuel ratio control of the combustor obtains a feedforward signal of an air flow rate at a predetermined air-fuel ratio based on a fuel flow rate command, and controls the air flow rate adjustment mechanism by this feedforward signal (patent) Reference 2).

Japanese Patent Application Laid-Open No. 8-210441 JP 7-269373 A

However, in the combustor of Patent Document 1, when the number of operations among the plurality of main premix burners is sequentially increased in response to an increase in load, if the load increases at the same number of operations, the air since the amount of fuel supply amount whereas the constant is increased, the fuel will become NO _X generation amount increases darker, NO _X generation amount approaching the stoichiometric air-fuel ratio of the main premix burner in combustion increasing the operation speed of the main premixed burner when significantly increasing the so thereby repeating the rapid action of lowering the concentration of the fuel thinly to NO _X generation amount, NO if the load increases or decreases rapidly There is a problem that the increase and decrease in _X emissions will increase.

  Further, in the air-fuel ratio control means of Patent Document 3, when the air flow rate adjusting mechanism is controlled by a feedforward signal of the air flow rate that becomes a predetermined air-fuel ratio obtained based on the fuel flow rate command, the air flow rate control system and the fuel flow rate control Since the response speeds of the systems are different, it is difficult to keep the air-fuel ratio constant in a transient state where the load fluctuates rapidly. That is, in general, since the response of the air flow rate control system is slower than that of the fuel flow rate control system, as shown in FIG. 6A, when the load of the gas turbine is drastically reduced, the response shown in FIG. Since the fuel supply amount to the premixing burner decreases earlier than the air supply amount to the premixing burner shown in FIG. 4C, the air-fuel ratio becomes large and misfire occurs as shown in FIG. As a result, stable combustion cannot be maintained.

In order to prevent the occurrence of such misfire, since previously the air-fuel ratio is set smaller achieve as to reduce the air flow rate, so that the NO _X generation amount by the combustion flame temperature becomes high is increased, empty The fuel ratio cannot be set too small. On the other hand, in order to eliminate the change in the air-fuel ratio due to the difference in response speed between the air flow rate control system and the fuel flow rate control system, the fuel flow rate control system should be controlled in accordance with the air flow rate control system with a slow response speed. However, in such a case, another problem arises that the load followability of the gas turbine is deteriorated.

  The present invention has been made in view of the above-described conventional problems, and maintains a stable lean premixed combustion while maintaining a stable lean premixed combustion by maintaining a constant air-fuel ratio of the premixed burner even in a transient state where the load fluctuates rapidly. It is an object of the present invention to provide a lean premixed combustion apparatus having good followability to fluctuations in the temperature and a method for controlling the same.

In order to achieve the above object, a lean premixed combustion apparatus according to the present invention is a combustion apparatus that combusts compressed air and fuel supplied from a compressor and supplies combustion gas to a turbine. A premix burner, at least one diffusion combustion type reheating burner, an air flow rate acquisition means for obtaining a premix burner air flow rate through the premix burner in the compressed air, and a total fuel supply amount corresponding to the load. A fuel flow rate command unit to be calculated, a multiplier for calculating a first fuel supply amount to the premix burner based on the determined premix burner air flow rate, and the total fuel supply the fuel flow rate setting unit having a subtractor for calculating a second amount of fuel supplied to the first fuel supply amount obtained by subtracting by the reheating burner from the amount, so that the first and second fuel supply amount Wherein the Ki予 mixed burner and a, a fuel supply valve unit for supplying fuel to each of the reheating burner.

According to this configuration, the first fuel supply flow rate to the premix burner is set based on the premix burner air flow rate that passes through the premix burner in the compressed air supplied from the compressor so as to have a constant air-fuel ratio. Therefore, the fuel supply amount to the premix burner by the fuel supply control system is controlled to correspond to the premix burner air flow rate by the air flow control system. However, since the air-fuel ratio to the premixed burner is always maintained constant, stable combustion without fear of causing misfire or incomplete combustion can be maintained, and generation of NO _x can be suppressed. Moreover, the air-fuel ratio, since the set based on the premix burner air flow rate, we are possible to set as large as possible in order to achieve the lean burn, thereby effectively suppressing the generation of the NO _X can do. In addition, since the second fuel supply amount obtained by subtracting the first fuel supply amount from the total fuel supply amount set in response to a rapid change in the load is supplied to the diffusion combustion type burner, Since the increase or decrease associated with the rapid load fluctuation is supplied to the tracking burner without a time delay, the followability to the sudden load fluctuation is improved. Here, the diffusion combustion type additional burner has a wide range of the air-fuel ratio for stable combustion, and therefore there is little risk of misfire or incomplete combustion even if the fuel supply amount increases or decreases rapidly. Further, reheating burner since the combustion in the hot combustion gases by premixing burner, does not increase the NO _X emissions.

  In this invention, it is preferable that the said air flow rate acquisition means calculates | requires the said premix burner air flow rate using the compressor map which shows the relationship between the pressure ratio of the said compressor, and an air flow rate. According to this configuration, the premix burner air flow rate can be obtained easily and accurately even when the load fluctuates rapidly.

  Further, when the compressor map is used, the air flow rate acquisition means obtains a compressor air amount from the compressor map based on a variable stationary blade angle of the compressor, and the compressor air amount and a part of the compressed air. It is preferable to obtain the premixed burner air flow rate based on the degree of opening of the bleed valve that discharges the air to the outside. According to this configuration, since the first fuel supply flow rate to the premix burner is set to be a constant air-fuel ratio based on the premix burner air flow rate, the air flow rate of the premix burner is subject to load fluctuations. Since it is not necessary to control following the control, the air-fuel ratio of the premix burner is always kept constant regardless of load fluctuations even if a variable stationary blade and a bleed valve, which are inexpensive and have a slow response speed, are used. be able to. The amount of compressor air here is the total amount of compressed air supplied from the compressor, and includes the amount sent to the combustor and the surplus extracted and discharged to the outside.

  The same effect as that of the lean premixed combustion apparatus described above can also be obtained by the control method of the lean premixed combustion apparatus according to the present invention.

According to the lean premixed combustion apparatus and its control method of the present invention, the fuel supply amount to the premix burner by the fuel supply control system corresponds to the premix burner air flow rate by the air flow control system with slow response. Because it is controlled, even if the load fluctuates suddenly, the air-fuel ratio to the premix burner can always be kept constant to maintain stable combustion without the risk of misfire or incomplete combustion, the generation of the NO _X can be suppressed. In addition, since the second fuel supply amount obtained by subtracting the first fuel supply amount from the total fuel supply amount is supplied to the diffusion combustion type additional burner, the followability of the fuel supply amount to a rapid load change is improved. To do. Moreover, since the reheating burner is a diffusion combustion type, the range of the air-fuel ratio for stable combustion is wide, so that there is little risk of misfire or incomplete combustion even if the fuel supply amount is increased or decreased rapidly.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram showing a gas turbine power generator to which a lean premixed combustion apparatus according to an embodiment of the present invention is applied. The gas turbine GT has a compressor 1, a combustor 2 and a turbine 3 as main components, and combusted compressed air A supplied from the compressor 1 is burned in the combustor 2, and a high-temperature and high-pressure combustion gas G generated thereby. Is supplied to the turbine 3. The compressor 1 is driven by the turbine 3 via the rotating shaft 5. The compressor 1 is provided with an angle adjustment mechanism 6 that adjusts the amount of compressor air by changing the angle of the upper stationary blade. In addition, a bleed valve 30 for releasing a part of the compressed air A to the outside is provided in the compressed air passage connecting the compressor 1 and the combustor 2. The turbine 3 also drives a generator 7 via a speed reducer 4. A gas fuel or liquid fuel such as natural gas fed from the fuel supply device 9 is supplied to the combustor 2 via the fuel control device 8. The combustor 2 and the fuel control device 8 constitute a part of the lean premixed combustion device of the present invention.

  FIG. 2 is a longitudinal sectional view showing the combustor 2. In this figure, the combustor 2 has a substantially cylindrical combustion cylinder 10 housed in a cylindrical housing H in a concentric arrangement, and a combustion chamber 11 is formed in the combustion cylinder 10. . A plurality of, for example, six combustors 2 are arranged at equal intervals around the rotation axis of the gas turbine. The housing H is coupled to a flange 13a provided on the main housing 13 covering the compressor 1 and the turbine 3 by a bolt (not shown) via a flange 14 provided on the base end side thereof. An end cover 12 is fixed to the front end side of the housing H with bolts (not shown).

  The base end of the support cylinder 52 is connected to the head of the housing H, and the head of the combustion cylinder 10 is fixed to the distal end portion (right end in the figure) of the support cylinder 52 so that the combustion cylinder 10 is supported. It is supported by the housing H via the cylinder 52. A proximal end portion of the combustion cylinder 10 is fitted into an inlet portion 54 of a transition duct that introduces the combustion gas G into the turbine 3. An annular air passage 16 that guides the compressed air A from the compressor 1 to the head of the combustion cylinder 10 is formed between the housing H and the combustion cylinder 10. An air introduction chamber 17 is formed inside the support cylinder 52, and a plurality of air introductions that guide the compressed air A sent through the air passage 16 into the air introduction chamber 17 into the support cylinder 52. A hole 18 is provided.

  A diffusion combustion type single pilot burner 20 that directly jets the fuel F into the combustion chamber 11 is provided at the center of the head of the combustion cylinder 10. On the outer periphery of the pilot burner 20, a lean premixed combustion type primary premixing burner 21 is provided for injecting an air-fuel mixture M generated by previously mixing the fuel F and the compressed air A into the combustion chamber 11. .

  The primary premixing burner 21 forms an annular premixing passage 24 between an inner peripheral tube 22 supported by the end cover 12 and an outer peripheral tube 23 concentric therewith, and a plurality of primary premixing burners 21 extend radially in the premixing passage 24. Primary fuel nozzles 25 are disposed, and a swirler 26 is disposed upstream of the primary fuel nozzles 25. A fuel conduit 27 is concentrically disposed inside the inner peripheral tube 22, and a fuel passage 28 for a pilot burner is formed inside the fuel conduit 27, and the primary premixing is provided between the fuel conduit 27 and the inner peripheral tube 22. A fuel passage 29 for the burner 21 is formed.

  The pilot burner 20 has a plurality of pilot injection holes 19 for pilots at the tip of the inner peripheral tube 22. The fuel passage 28 inside the fuel conduit 27 is connected to a pilot fuel introduction port 31 provided in the inner peripheral pipe 22. Each primary fuel nozzle 25 facing the premixing passage 24 has a plurality of fuel injection holes arranged in the radial direction and communicates with a fuel passage 29 inside the inner peripheral tube 22, and the fuel passage 29 is connected to the inner peripheral tube 22. Is connected to a primary fuel introduction port 32 provided in.

  A lean premix combustion type secondary premix burner 35 having an annular premix passage 34 concentric with the primary premix burner 21 is provided on the outer periphery of the primary premix burner 21. A plurality of secondary fuel nozzles 37 are arranged at equal intervals in the circumferential direction at an annular air inlet 36 opened radially outward of the secondary premix burner 35. The secondary fuel nozzle 37 is connected to a secondary fuel inlet 33 provided in the end cover 12. In addition, a swirler 38 located downstream of the secondary fuel nozzle 37 is disposed at the air inlet 36. Fuel F is supplied to the pilot fuel introduction port 31, the primary fuel introduction port 32, and the secondary fuel introduction port 33 from the fuel supply device 9 of FIG.

  The premixed gas M injected into the combustion chamber 11 from the primary premixing burner 21 and the secondary premixing burner 35 burns in the combustion chamber 11 to form a first combustion region 11a. On the downstream side of the first combustion region 11 a in the combustion cylinder 10, a plurality of remedy air holes 44 formed by penetrating a short pipe are arranged at equal intervals in the circumferential direction. A diffusion combustion type reheating burner 47 is attached to a portion of the housing H facing each retreating air hole 44 so that each fuel ejection hole faces the retreating air hole 44. The refueling burner 47 injects the fuel F supplied from the fuel supply device 9 of FIG. 1 via the fuel control device 8 into the combustion cylinder 10 through the reheating air hole 44, A second combustion region 11b is formed on the downstream side of the first combustion region 11a. A spark plug 40 is mounted on the upstream side of the reheating burner 47 on the downstream side of the pilot burner 20 and the premixing burners 21 and 35 in the combustion cylinder 10.

Next, the operation of the combustor 2 will be described. The combustor 2 actuates the pilot burner 20 only during startup and diffusion operation (non-low NO _X operation), thereby diffusion combustion by injecting fuel F from the pilot injection port 19 of the fuel passage 28. During operation the low NO _X operates the primary and secondary premix burner 21 and 35, to the lean burn in the first combustion zone 11a. Thus, the combustion temperature decreases, generation of the NO _X is suppressed. Further, since the fuel F ejected from the reheating burner 47 is introduced into the second combustion region 11b, which is considerably heated by the first combustion region 11a, NO _X is generated even in the diffusion combustion. Is suppressed.

  FIG. 3 is a system diagram showing a lean premixed combustion apparatus including a controller CT and a combustor 2 for the entire gas turbine GT including the fuel control apparatus 8. The lean premixing combustion apparatus is roughly divided into configurations, and an air flow rate obtaining means 49 for obtaining a premixed burner air flow rate through the premixed burners 21 and 35 in the compressed air A from the compressor 1 is obtained. Based on the premixed air flow rate, the first fuel supply amount to the premixed burners 21 and 35 is set so as to obtain a constant air-fuel ratio, and the total fuel corresponding to the load of the gas turbine GT is determined from the generator output command value. A fuel flow rate setting unit 50 for subtracting the first fuel supply amount from the supply amount to set a second fuel supply amount to the follow-up burner 47, and a premix burner so as to have the set first and second fuel supply amounts 21 and 35 and a fuel supply valve 51 for supplying fuel F to each of the additional burner 47. The air flow rate acquisition means 49, the fuel flow rate setting unit 50, and the fuel supply valve unit 51 constitute the fuel control device 8 of FIG.

  The air flow rate acquisition means 49 in FIG. 3 obtains the premixed burner air flow rate using a compressor map obtained experimentally in advance prior to operation. First, the compressor map will be described. 1 is actually operated, the actual angle of the variable stator blade 53 of the compressor 1 adjusted by the variable stator blade angle adjusting mechanism 6 of FIG. 3 and the rotation obtained by the tachometer 61. Based on the rotational speed of the shaft 5, that is, the rotational speed of the compressor 1 and the outlet pressure of the compressor 1 obtained by the pressure sensor 65, the relationship between the pressure ratio of the compressor 1 and the air flow rate as shown in FIG. Compressor map indicating FIG. 4 shows an example of a compressor map. C1 and C2 are respectively 10 and 10 when the rotational speed of the compressor 1 is 100% (rated rotational speed) and the actual angle of the variable stationary blade 53 is 10 with respect to the reference angle of the rated value. C3 and C4 are the characteristic curves when shifted by 5 ° and 5 °, respectively, and the actual angle of the variable stator blade 53 is 10 ° and 5 ° with respect to the reference angle of the rated value when the rotation speed of the compressor 1 is 90%, respectively. It is each characteristic curve when it deviates. This compressor map is stored as a data table in the compressor air amount calculation unit 60 of FIG.

  The air flow rate command unit 57 calculates a load factor (ratio to the rated load) corresponding to the generator output detection signal S1 obtained by measuring the power of the generator 7, and the variable stator blade angle command signal obtained based on the load factor. S2 and the extraction valve opening command signal S3 are output to the variable stationary blade angle adjustment mechanism 6 and the extraction valve 30, respectively. The variable stationary blade angle adjusting mechanism 6 adjusts the mounting angle of the variable stationary blade 53 based on the variable stationary blade angle command signal S2 to change the outflow angle of the variable stationary blade 53, thereby passing the compressor 1 through the compressor 1. Adjust the air volume. The bleed valve 30 is adjusted to a valve opening corresponding to the bleed valve opening command signal S3, and the combustion air BA and the cooling air supplied to the combustor 2 of the compressed air A sent from the compressor 1 are cooled. The discharge amount of the bleed air EA discharged to the outside as a surplus with respect to each air amount of CA is adjusted. The variable stator blade angle adjusting mechanism 6 and the bleed valve 30 adjust the amount of air supplied to the combustor 2 so as to correspond to the output fluctuation (load fluctuation) of the generator 7.

  The air flow rate acquisition means 49 calculates the air flow rates of the premix burners 21 and 35 by performing the following calculation. That is, the compressor air amount calculation unit 60 receives the variable stator blade angle detection signal S4, the compressor rotational speed detection signal S5, and the pressure detection input from the variable stator blade angle adjustment mechanism 6, the rotational speed meter 61, and the pressure sensor 65, respectively. The compressor air amount is obtained by comparing the pressure ratio obtained from the signal S6 with the compressor map shown in FIG. 4, and the compressor air amount signal S7 is output. Here, the compressor air amount is the total amount of compressed air A supplied from the compressor 1 and includes the amount sent to the combustor 2 and the surplus extracted and discharged by the extraction valve 30. It is out.

  On the other hand, the extraction air amount calculation unit 62 calculates the flow rate of the extraction air EA based on the extraction valve opening detection signal S11 input from the extraction valve 30, and outputs the extraction air amount signal S12. The first adder / subtractor 63 subtracts the extracted air amount signal S12 from the compressor air amount signal S7 to calculate a combustor air amount, and outputs a combustor air amount signal S13. Further, the first multiplier 64 calculates the premixed burner air flow rate by multiplying the combustor air amount signal S13 by the premixed burner inflow air flow rate coefficient obtained in advance, and outputs the premixed burner air flow rate signal S14. .

The fuel flow rate command unit 67 is based on the generator output command value (load command value) and the generator output detection signal (load detection signal) S1, and the total fuel supply amount for feedback control corresponding to the load fluctuation, That is, the total fuel supply amount necessary to obtain a predetermined generator output is calculated, and the total fuel supply command signal S16 is output. In the fuel flow rate setting unit 50, second multiplier 68, NO _X emissions multiplied by the premixed burner optimal fuel-air ratio which minimizes the premixed burner air flow rate signal S14 from the first multiplier 64 The first fuel supply amount that is the fuel flow rate supplied to the premix burners 21 and 35 is calculated so that the air-fuel ratio is always constant, and the first fuel supply is supplied to the first flow rate-valve opening conversion unit 69. An amount command signal S17 is output. The first flow rate-valve opening degree conversion unit 69 calculates the valve opening degree of the premix burner valve 72 for obtaining the fuel supply amount indicated by the first fuel supply amount command signal S17, and calculates the premix burner valve. An opening command signal S18 is output.

  On the other hand, the second adder / subtractor 70 of the fuel flow rate setting unit 50 subtracts the first fuel supply amount of the first fuel supply amount command signal S17 from the total fuel supply amount of the total fuel supply amount command signal S16, and the additional burner. A second fuel supply amount that is a fuel flow rate supplied to the fuel flow rate 47 is calculated, and a second fuel supply amount command signal S 19 is output to the second flow rate-valve opening degree conversion unit 71. The second flow rate-valve opening degree conversion unit 71 calculates the valve opening degree of the additional burner valve 73 for obtaining the fuel supply amount indicated by the second fuel supply amount command signal S19, and calculates the additional burner valve. An opening command signal S20 is output.

In the fuel supply valve section 51, the premix burner valve 72 is adjusted to a valve opening corresponding to the premix burner valve opening command signal S18 from the first flow rate-valve opening conversion section 69, so that the first A fuel supply amount of fuel F is supplied to the premix burners 21 and 35. At this time, the fuel F is distributed to the primary premix burner 21 and the secondary premix burner 35 by the distributor 75. Since the first fuel supply amount to the premix burners 21 and 35 is the fuel flow rate set to the optimum air-fuel ratio based on the premix burner air amount corresponding to the load fluctuation as described above, Even when sudden fluctuations occur, the air-fuel ratio of the premix burners 21 and 35, which is a lean premix combustion method, is controlled so as to always have a required constant value. It can be held to no stable combustion danger which occurs, it is possible to suppress the generation of nO _X. Control of the fuel supply to the pilot burner 20 at the start-up and during the diffusion operation is performed by adjusting the opening of a pilot burner valve (not shown).

  On the other hand, the refueling burner valve 73 is adjusted to a valve opening corresponding to the reheating burner valve opening command signal S20 from the second flow rate-valve opening converting unit 71, and the fuel of the second fuel supply amount is adjusted. F is supplied to the burner 47. This second fuel supply amount is obtained by subtracting the first fuel supply amount (corresponding to S17) from the total fuel supply amount (corresponding to S16) necessary to obtain the commanded generator output. Even if the fuel supply amount fluctuates with a delay with respect to the load, the second fuel supply amount (corresponding to S20) fluctuates rapidly. That is, the sum of the first and second fuel supply amounts is always controlled to match the total fuel supply amount calculated by the fuel flow rate command unit 67. In other words, the increase or decrease of the total fuel supply amount due to the load change is supplied to the follow-up burner 47 as the second fuel supply amount without a time delay so as to correspond to the rapid load change.

Here, the reheating burner 47 is a diffusion combustion type, and therefore has a wide air-fuel ratio range for stable combustion, so that there is little risk of misfire or incomplete combustion even if the fuel supply amount is increased or decreased rapidly. Further, reheating burner 47, so injects fuel F into the second combustion area 11b that is a high temperature due to the hot combustion gases G from the first combustion area 11a, it does not increase the amount of generation of NO _X. In particular, as compared with the case of burning only the diffusion burner, the amount of the NO _X is reduced. According to actual measurement, the second fuel supply flow rate supplied to the reheating burner 47 is within the scope of the feed rate of up to 20-25% relative to the total fuel supply flow rate, at all not increase the NO _X than when no additional heating Rather, a slight decrease has been confirmed. Thus, while suppressing the generation of NO _X, followability of the fuel supply amount to the sudden change in the load is increased.

  Next, the operation at the time of a sudden change in the load will be described with reference to the timing chart of FIG. As shown in FIG. 11A, when a command for suddenly reducing the load is issued, the air supply amount to the premix burners 21 and 35 corresponds to the load fluctuation as shown in FIG. The air supply amount is controlled by adjusting the air flow rate of the compressor 1 by changing the angle of the variable stationary blade 53 and changing the valve opening of the extraction valve 30. Since it is performed by adjusting the amount of release, the response speed is slow.

On the other hand, as shown in FIG. 5B, the first fuel supply amount supplied to the lean premix combustion type premix burners 21 and 35 is the angle of the variable stationary blade 53 and the valve opening degree of the extraction valve 30. After calculating the combustor air amount by subtracting the extracted air amount from the compressor air amount obtained from the above, it is set based on the air supply amount to the premix burners 21 and 35 calculated based on this combustor air amount. This corresponds to a change in the amount of air supplied to the premix burners 21 and 35 having a slow response. As a result, as shown in FIG. 5E, the air-fuel ratio of the premix burners 21 and 35 always maintains a required constant value regardless of the rapid fluctuation of the load. Generation of _X can be suppressed.

  On the other hand, as shown in FIG. 3C, the second fuel supply amount supplied to the reheating burner 47 is the first fuel of the total fuel supply amount set so as to correspond to the rapid decrease in load. As the supply rate decreases slowly, the excess fuel amount is reduced in real time. Thereby, the followability of the generator output with respect to the rapid reduction of the load is improved.

  In the above embodiment, the case where the compressor map is used to determine the premix burner air flow rate to the premix burners 21 and 35 has been described as an example. However, the present invention is not limited to this, and the compression map is used. If the machine air quantity or premix burner air flow rate can be measured directly with an air flow meter, the compressor map is not required.

  Further, the number of the combustors 2 is not limited to a plurality, and may be one as seen in a so-called single can combustion apparatus. The reheating burner 47, which is a diffusion combustion type burner, does not have to be arranged downstream of the premixing burners 21 and 35, and may be arranged upstream or at the same position in the gas flow direction.

1 is a schematic configuration diagram showing a gas turbine power generator to which a lean premixed combustion apparatus of the present invention is applied. It is a longitudinal section showing a combustor in a gas turbine power generator same as the above. It is a systematic diagram showing a lean premixed combustion apparatus according to an embodiment of the present invention configured using the above combustor. It is a characteristic view which shows an example of the compressor map used with a lean premix type combustion apparatus same as the above. (A)-(e) is a timing chart which respectively shows the load, the 1st and 2nd fuel supply amount, the premix burner air supply amount, and the premix burner air fuel ratio in the lean premix type combustion apparatus same as the above. 6 is a timing chart showing a load, a premixed burner fuel supply amount, a premixed burner air supply amount, and a premixed burner air-fuel ratio in a conventional lean premixed combustion apparatus, respectively.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Compressor 3 Turbine 21,35 Premix burner 30 Extraction valve 47 Reheating burner 49 Air flow rate acquisition means 50 Fuel flow rate setting part 51 Fuel supply valve part 53 Variable stationary blade A Compressed air

Claims (6)

A combustion apparatus for combusting compressed air and fuel supplied from a compressor and supplying combustion gas to a turbine,
At least one premix burner;
At least one diffusion combustion type burner,
An air flow rate acquisition means for obtaining a premix burner air flow rate through the premix burner of the compressed air;
A fuel flow rate command unit for calculating a total fuel supply amount corresponding to the load ;
A multiplier for calculating a first fuel supply amount to the premix burner based on the determined premix burner air flow rate, and the first fuel supply amount from the total fuel supply amount; A fuel flow rate setting unit having an adder / subtractor for subtracting the value to calculate the second fuel supply amount to the additional burner;
A fuel supply valve unit for supplying fuel to each of the premixed burner and the reheating burner so that said first and second fuel supply amount,
A lean premixed combustion device.   2. The lean premixing combustion apparatus according to claim 1, wherein the air flow rate acquisition means obtains the premixed burner air flow rate using a compressor map indicating a relationship between a pressure ratio of the compressor and an air flow rate.   3. The air flow rate acquisition means according to claim 2, wherein the air flow rate acquisition means obtains a compressor air amount from the compressor map based on a rotational speed and pressure ratio of the compressor and a variable stationary blade angle, and the compressor air amount and the compressed air A lean premixing type combustion apparatus for obtaining the premixed burner air flow rate based on an opening degree of a bleed valve that discharges a part to the outside. A method of controlling a combustion apparatus comprising at least one premixing burner and at least one diffusion combustion type reheating burner, which burns compressed air and fuel supplied from a compressor and supplies combustion gas to a turbine. And
Obtaining a premix burner air flow rate through the premix burner of the compressed air;
Calculating a total fuel supply corresponding to the load;
Calculating a first fuel supply amount to the premix burner so as to obtain a constant air-fuel ratio based on the determined premix burner air flow rate ;
Calculating a second amount of fuel supplied to the reheating burner from said total fuel supply amount by subtracting said first fuel supply amount,
And supplying fuel to each of said first and second fuel supply amount and the premixed burner and the reheating burner so,
A control method for a lean premixed combustion apparatus comprising:   5. The control method for a lean premixed combustion apparatus according to claim 4, wherein the premix burner air flow rate is obtained by using a compressor map indicating a relationship between the pressure ratio of the compressor and the air flow rate.   6. The compressor air amount according to claim 5, wherein a compressor air amount is obtained from the compressor map based on a rotation speed and pressure ratio of the compressor and a variable stationary blade angle, and the compressor air amount and a part of the compressed air are released to the outside. A control method for a lean premixed combustion apparatus for obtaining the premixed burner air flow rate based on an opening degree of a bleed valve.

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