Gas turbine combustor device

Abstract

Gas turbine combustor device (3) comprising: a preburner (5); a flow pilot valve (26) which regulates a flow rate of fuel to be supplied to the preburner (5); a premix combustion type main burner (6) disposed on an outer peripheral side of the preburner (5); a plurality of main flow control valves (27a, 27b, 27c, 27d) which regulate flow rates of fuel which is individually supplied to a plurality of burner sectors (20a to 20d; 20a to 20f; 20a, 20b) into which the main burner (6) is divided in a circumferential direction; and a control unit (30) configured to control the flow pilot valve (26) and the plurality of main flow control valves (27a, 27b, 27c, 27d), characterized in that the control unit (30) controls the plurality of main flow control valves (27a, 27b, 27c, 27d) such that, when fuel is to be supplied to all of the plurality of burner sectors (20a to 20d; 20a to 20f; 20a, 20b), a fuel flow rate of at least one burner sector increases and a fuel flow rate of another burner sector or other burner sectors decreases with respect to an average value of the fuel flow rates of the plurality of burner sectors (20a to 20d; 20a to 20f; 20a, 20b), wherein a difference in the fuel flow rate occurs between the at least one burner sector and the other burner sector or the other burner sectors among the plurality of burner sectors (20a to 20d; 20a to 20f; 20a, 20b).

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention

[0001] The present invention relates to a gas turbine combustor device. 2. Description of the state of the art

[0002] A gas turbine combustor disclosed in JP 2014-240635 A includes a preburner and a main burner arranged on the outer peripheral side of the preburner. The preburner is of the diffusion combustion type and directly injects fuel into a combustion chamber. The main burner is of the premixed combustion type and mixes fuel and air in a premixed flow path and supplies the mixture to the combustion chamber. Although premixed combustion is poor in flame stability compared to diffusion combustion, it reduces NOx emissions.

[0003] The gas turbine combustor device disclosed in JP 2014-240635 A further comprises a flow pilot valve that regulates the flow rate of fuel to be supplied to the pre-burner, four main flow control valves, each of which regulates the flow rate of fuel to be supplied to each of four burner sectors into which the main burner is divided in a circumferential direction, and a control unit configured to control the flow pilot valve and the main flow control valves.

[0004] The control unit controls the flow pilot valve and the main flow control valves after the gas turbine is activated until the gas turbine enters full load operation. Specifically, the control unit performs control such that fuel is first supplied only to the preburner, and then increases the fuel flow rate. After that, the control unit switches the control such that fuel is supplied to the preburner and one of the burner sectors, and then increases the fuel flow rates of them. Then, the control unit switches the control such that fuel is supplied to the preburner and two of the burner sectors, and then increases the fuel flow rates of them. After that, the control unit switches the control such that fuel is supplied to the preburner and three of the burner sectors, and then increases the fuel flow rates of them.The control unit then switches the control to supply fuel to the pre-burner and the four burner sectors, and then increases the fuel flow rates from them.

[0005] The publication DE 10 2013 016 202 A1 describes a burner head of a burner and a gas turbine with such a burner. Furthermore, DE 10 2013 016 202 A1 shows a first burner stage with at least one fuel nozzle. Furthermore, DE 10 2013 016 202 A1 proposes at least one further, preferably at least two further burner stages, each with at least one associated fuel nozzle. SUMMARY OF THE INVENTION

[0006] Although JP 2014-240635 A does not include a clear description of when fuel is supplied to all burner sectors, the control unit controls the fuel flow rates of the respective burner sectors to be uniform among them. When fuel is supplied to all burner sectors, the fuel flow rate of the premixed combustion type main burner is extremely higher than the fuel flow rate of the diffusion combustion type preburner. Therefore, a phenomenon occurs that flame fluctuation is increased. The present inventors have noted that when fuel is supplied to all burner sectors, if the fuel flow rate of at least one burner sector is made different from that of the other burner sectors, it is possible to suppress flame fluctuation to improve combustion stability.

[0007] It is an object of the present invention to provide a gas turbine combustor device which can achieve an improvement in combustion stability.

[0008] To achieve the above-described object, according to an embodiment of the present invention, there is provided a gas turbine combustor apparatus including a preburner, a flow pilot valve that regulates a flow rate of fuel to be supplied to the preburner, a premixed combustion type main burner disposed on an outer peripheral side of the preburner, a plurality of main flow control valves that regulate flow rates of fuel to be individually supplied to a plurality of burner sectors into which the main burner is divided in a circumferential direction, and a control unit configured to control the flow pilot valve and the plurality of main flow control valves.The control unit controls the plurality of main flow control valves such that, when fuel is to be supplied to all of the plurality of burner sectors, a fuel flow rate of at least one burner sector increases and a fuel flow rate of another burner sector or other burner sectors decreases with respect to an average of the fuel flow rates of the plurality of burner sectors, wherein a difference in the fuel flow rate occurs between the at least one burner sector and the other burner sector or the other burner sectors among the plurality of burner sectors.

[0009] According to the present invention, an improvement in combustion stability can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view illustrating a structure of a gas turbine combustor apparatus according to an embodiment of the present invention and a configuration of a gas turbine including the gas turbine combustor apparatus; Fig. 2 is a cross-sectional view along a line II-II of Fig. 1; Fig. 3 is a timing chart illustrating the transition of fuel supply in the gas turbine combustor apparatus according to the embodiment of the present invention; Fig. Figure 4 is a time diagram showing the transition of the fuel flow rate after a time T of Fig. 3 represents; Fig. 5 is a schematic view illustrating six burner sectors and a relationship between fuel flow rates of the six burner sectors in a first modification of the present invention; Fig. 6 is a schematic view illustrating six burner sectors and a relationship between fuel flow rates of the six burner sectors in a second modification of the present invention; and Fig. 7 is a schematic view illustrating two burner sectors and a relationship between fuel flow rates of the two burner sectors in a third modification of the present invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] An embodiment of the present invention will be described with reference to the drawings.

[0011] Fig. 1 is a schematic view illustrating a structure of a gas turbine combustor device according to the present embodiment and a configuration of a gas turbine including the gas turbine combustor device. Fig. 2 is a cross-sectional view along a line II-II of Fig. 1. It should be noted that in Fig. 2 Illustrations of a lining and a housing have been omitted for the sake of convenience.

[0012] A gas turbine plant of the present embodiment includes a generator 1 and a gas turbine that drives the generator 1. The gas turbine includes a compressor 2 that generates high-pressure air, a combustor 3 that combusts fuel and the high-pressure air from the compressor 2, and a turbine 4 driven by combustion gas from the combustor 3. The generator 1 and the compressor 2 are coaxially connected to the turbine 4 and driven by the turbine 4.

[0013] The combustor device 3 (gas turbine combustor device) comprises a pre-burner 5, a main burner 6 arranged on the outer peripheral side of the pre-burner 5, and a cylindrical liner 7 arranged on the downstream side (on the right side in Fig. 1) of the preburner 5 and the main burner 6. On the outside of the liner 7 (namely, between the liner 7 and a casing 8), an air flow path 9 is formed, which supplies the high-pressure air from the compressor 2 to the preburner 5 and the main burner 6. A combustion chamber 10 is formed on the inside of the liner 7.

[0014] The preburner 5 is of the diffusion combustion type and includes a fuel nozzle 11 that injects fuel into the combustion chamber 10, an air flow path 12 formed on the outer peripheral side of the fuel nozzle 11, and a plurality of swirl vanes 13 arranged in the air flow path 12 to generate swirling flows. The air flow path 12 is connected to the above-described air flow path 9. The preburner 5 injects fuel from the fuel nozzle 11 into the combustion chamber 10 and supplies air from the air flow path 12 to the combustion chamber 10. Note that the preburner 5 is not limited to the diffusion combustion type and may be of other combustion types.

[0015] The main burner 6 is of the premix combustion type and includes an inner cylinder 14, an outer cylinder 15, a plurality of barrier walls 17a to 17l, a plurality of fuel nozzles 18, and an annular flame holder 19. The inner cylinder 14 is disposed on the outer peripheral side of the preburner 5, and the outer cylinder 15 is disposed on the outer peripheral side of the inner cylinder 14. The plurality of barrier walls 17a to 17l partition the space between the inner cylinder 14 and the outer cylinder 15 in a circumferential direction to form a plurality of (12 in the present embodiment) premix flow paths 16. The plurality of fuel nozzles 18 inject fuel into the plurality of premix flow paths 16. In the present embodiment, 24 fuel nozzles 18 are provided, that is, two fuel nozzles 18 are provided for each of the premix flow paths 16.The flame holder 19 is arranged on the downstream side of the plurality of premixed flow paths 16. The premixed flow paths 16 are connected to the above-described air flow path 9. The main burner 6 mixes fuel from the fuel nozzles 18 and air from the air flow path 9 in the premixed flow paths 16 thereof to form a mixture and supplies the mixture to the combustion chamber 10.

[0016] The main burner 6 is divided into four burner sectors 20a to 20d by the barrier walls 17a, 17d, 17g, and 17j. Each of the burner sectors 20a to 20d includes three sets of a premix flow path 16 and a fuel nozzle 18. The fuel and air supplied from the preburner 5 and any one of the burner sectors 20a to 20d combust in the combustion chamber 10, thus generating combustion gas.

[0017] The combustion chamber device 3 further includes a fuel system 21 that supplies fuel to the preburner 5 and to the burner sectors 20a to 20d, and a control unit 30. The fuel system 21 includes a common fuel system 22, a pilot fuel system 23, and main fuel systems 24a to 24d. The common fuel system 22 is connected to a fuel supply source (not shown), and the pilot fuel system 23 is branched off from the common fuel system 22 and supplies fuel to the preburner 5. The main fuel systems 24a to 24d are branched off from the common fuel system 22 and each supply fuel to the burner sectors 20a to 20d.

[0018] A shutoff valve 25 is provided for the common fuel system 22. A flow pilot valve 26 is provided for the pilot fuel system 23, and main flow control valves 27a to 27d are provided for the main fuel systems 24a to 24d, respectively. The flow pilot valve 26 regulates the flow rate of fuel to be supplied to the preburner 5, more specifically to the fuel nozzle 11. Each of the main flow control valves 27a to 27d regulates the flow rate of fuel to be supplied to a corresponding burner sector, more specifically to six fuel nozzles 18, through a head (not shown).

[0019] The control unit 30 controls the flow pilot valve 26 and the main flow control valves 27a to 27d according to an operating situation of the gas turbine to control the supply area and the flow rate of fuel. Details thereof will be described below with reference to Fig. 3 and Fig. 4 described.

[0020] Fig. 3 is a timing chart illustrating a transition of fuel supply in the gas turbine combustor device in the present embodiment. A top portion of Fig. 3 shows the transition of a fuel supply area (hatched line section) under the preburner 5 and the burner sectors 20a to 20d. A bottom section of Fig. 3 indicates a transition of a fuel flow rate F1 of the pre-burner 5, a fuel flow rate F2a of the burner sector 20a, a fuel flow rate F2b of the burner sector 20b, a fuel flow rate F2c of the burner sector 20c and a fuel flow rate F2d of the burner sector 20d. Fig. 4 is a time diagram showing a transition of the fuel flow rate F1 of the pre-burner 5, a fuel flow rate F2 of the main burner 6, the fuel flow rate F2a of the burner sector 20a, the fuel flow rate F2b of the burner sector 20b, the fuel flow rate F2c of the burner sector 20c and the fuel flow rate F2d of the burner sector 20d after a time T in Fig. 3 indicates.

[0021] At the time of ignition (activation) of the gas turbine, the control unit 30 controls the shutoff valve 25, the flow pilot valve 26, and the main flow control valves 27b and 27d to enter an open state, and controls the main flow control valves 27a and 27c to enter a closed state. Consequently, fuel and high-pressure air are supplied from the pre-burner 5 and the burner sectors 20b and 20d to the combustion chamber 10.

[0022] After the gas turbine is ignited (activated), the control unit 30 controls the shutoff valve 25 and the flow pilot valve 26 to enter an open state, and controls the main flow control valves 27a to 27d to enter a closed state. Consequently, fuel and high-pressure air are supplied from the pre-burner 5 to the combustion chamber 10. The control unit 30 then increases the opening of the flow pilot valve 26 until the rotational speed of the turbine 4 reaches a rated speed, in other words, until the gas turbine reaches a full-speed no-load (FSNL) state, to increase the fuel flow rate F1 of the pre-burner 5.

[0023] After the rotational speed of the turbine 4 reaches the rated speed, power generation of the generator 1 is started, and the load on the gas turbine is gradually increased until the gas turbine reaches a full speed full load (FSFL) state. Specifically, the control unit 30 first switches the main flow control valve 27a from a closed state to an open state. Consequently, fuel and high-pressure air are supplied from the pre-burner 5 and the burner sector 20a to the combustion chamber 10. At the time of this switching of the main flow control valve 27a, the control unit 30 decreases the opening of the flow pilot valve 26 to decrease the flow rate F1 of the pre-burner 5. This suppresses a change from the total fuel flow rate F1 to a total fuel flow rate (F1 + F2a).Thereafter, the control unit 30 increases the opening of the flow pilot valve 26 and the opening of the main flow control valve 27a to increase the fuel flow rate F1 of the pre-burner 5 and the fuel flow rate F2a of the burner sector 20a.

[0024] After the load on the gas turbine reaches a first value, the control unit 30 switches the main flow control valve 27d from a closed state to an open state. Consequently, fuel and high-pressure air are supplied from the pre-burner 5 and the burner sectors 20a and 20d to the combustion chamber 10. At the time of this switching of the main flow control valve 27d, the control unit 30 reduces the opening of the flow pilot valve 26 to reduce the fuel flow rate F1 of the pre-burner 5. This suppresses a change from the total fuel flow rate (F1 + F2a) to the total fuel flow rate (F1 + F2a + F2d).Thereafter, the control unit 30 increases the opening of the flow pilot valve 26, the opening of the main flow control valve 27a, and the opening of the main flow control valve 27d to increase the fuel flow rate F1 of the pre-burner, the fuel flow rate F2a of the burner sector 20a, and the fuel flow rate F2d of the burner sector 20d. At this time, the fuel flow rate F2a of the burner sector 20a and the fuel flow rate F2d of the burner sector 20d are equal to each other.

[0025] After the load on the gas turbine reaches a second value (where the second value > the first value), the control unit 30 switches the main flow control valve 27b from a closed state to an open state. Consequently, fuel and high-pressure air are supplied from the pre-burner 5 and the burner sectors 20a, 20b, and 20d to the combustion chamber 10. At the time of this switching of the main flow control valve 27b, the control unit 30 reduces the opening of the flow pilot valve 26 to reduce the fuel flow rate F1 of the pre-burner 5. This suppresses a change from the total fuel flow rate (F1 + F2a + F2d) to a total fuel flow rate (F1 + F2a + F2b + F2d).Thereafter, the control unit 30 increases the opening of the flow pilot valve 26, the opening of the main flow control valve 27a, the opening of the main flow control valve 27b, and the opening of the main flow control valve 27d to increase the fuel flow rate F1 of the pre-burner 5, the fuel flow rate F2a of the burner sector 20a, the fuel flow rate F2b of the burner sector 20b, and the fuel flow rate F2d of the burner sector 20d. At this time, the fuel flow rate F2a of the burner sector 20a, the fuel flow rate F2b of the burner sector 20b, and the fuel flow rate F2d of the burner sector 20d are equal to each other.

[0026] After the load on the gas turbine reaches a third value (where the third value > the second value) (time T), the control unit 30 switches the main flow control valve 27c from a closed state to an open state. Consequently, fuel and high-pressure air are supplied from the pre-burner 5 and the burner sectors 20a, 20b, 20c, and 20d to the combustion chamber 10. At the time of this switching of the main flow control valve 27c, the control unit 30 reduces the opening of the flow pilot valve 26 to reduce the fuel flow rate F1 of the pre-burner 5. This suppresses a change from the total fuel flow rate (F1 + F2a + F2b + F2d) to a total fuel flow rate (F1 + F2a + F2b + F2c + F2d).Thereafter, the control unit 30 increases the opening of the flow pilot valve 26, the opening of the main flow control valve 27a, the opening of the main flow control valve 27b, the opening of the main flow control valve 27c, and the opening of the main flow control valve 27d to increase the fuel flow rate F1 of the pre-burner 5, the fuel flow rate F2a of the burner sector 20a, the fuel flow rate F2b of the burner sector 20b, the fuel flow rate F2c of the burner sector 20c, and the fuel flow rate F2d of the burner sector 20d.

[0027] At this time, as a characteristic of the present embodiment, the control unit 30 controls the main flow control valves 27a to 27d such that a difference in fuel flow rate occurs between the burner sectors 20a and 20c and the burner sectors 20b and 20d. Specifically, with respect to an average value of the fuel flow rates of the burner sectors 20a to 20d (= (F2a + F2b + F2c + F2d) / 4), the fuel flow rate F2a of the burner sector 20a and the fuel flow rate F2c of the burner sector 20c are increased, while the fuel flow rate F2b of the burner sector 20b and the fuel flow rate F2d of the burner sector 20d are decreased. Therefore, although a phenomenon of amplification of fluctuations in the combustion flame is likely to occur when fuel is supplied to all the burner sectors 20a to 20d, this phenomenon can be suppressed. Consequently, an improvement in combustion stability can be achieved.

[0028] Furthermore, in the present embodiment, each fuel flow rate of the burner sectors 20a to 20d alternately increases and decreases in the circumferential direction with respect to the average value of the fuel flow rates of the burner sectors 20a to 20d. Therefore, compared to an alternative case in which each fuel flow rate does not alternately increase and decrease in the circumferential direction, combustion stability can be improved. Consequently, a local increase in the metal temperature on the downstream side can be suppressed.

[0029] It should be noted that, although the above-described embodiment takes as an example a case where the main burner 6 is divided into the four burner sectors 20a to 20d by the barrier walls 17a, 17d, 17g and 17j and the fuel system 21 has four sets of a main fuel system and a main flow control valve individually corresponding to the four burner sectors 20a to 20d, this is not limitative.

[0030] As in the case of a first modification, which Fig. For example, as shown in Fig. 5, the main burner 6 may be divided into six burner sectors 20a to 20f by barrier walls 17a, 17c, 17e, 17g, 17i, and 17k, and the fuel system 21 may include six sets of a main fuel system and a main flow control valve, each of which corresponds individually to the six burner sectors 20a to 20f. In this modification, when fuel is to be supplied to all burner sectors 20a to 20f, the control unit 30 controls the main flow control valves such that a difference in fuel flow rate occurs between the burner sectors 20a, 20c, and 20e and the burner sectors 20b, 20d, and 20f.Specifically, with respect to an average value of the fuel flow rates of the burner sectors 20a to 20f (= (F2a + F2b + F2c + F2d + F2e + F2f) / 6), the fuel flow rate F2b of the burner sector 20b, the fuel flow rate F2d of the burner sector 20d, and the fuel flow rate F2f of the burner sector 20f are increased, while the fuel flow rate F2a of the burner sector 20a, the fuel flow rate F2c of the burner sector 20c, and the fuel flow rate F2e of the burner sector 20e are decreased. Consequently, advantageous effects similar to those in the above-described embodiment can be obtained.

[0031] Alternatively, as in the case of a second modification, which in Fig. As shown in Figure 6, when fuel is to be supplied to all burner sectors 20a to 20f, the control unit 30 controls the main flow control valves such that a difference in fuel flow rate occurs between the burner sectors 20a, 20b, 20c, and 20e and the burner sectors 20d and 20f. Specifically, with respect to an average of the fuel flow rates of the burner sectors 20a to 20f, the fuel flow rate F2d of the burner sector 20d and the fuel flow rate F2f of the burner sector 20f are increased, while the fuel flow rate F2a of the burner sector 20a, the fuel flow rate F2b of the burner sector 20b, the fuel flow rate F2c of the burner sector 20c, and the fuel flow rate F2e of the burner sector 20e are decreased. With this modification, although advantageous effects the same as those in the first modification cannot be obtained, the combustion stability can be improved.

[0032] As another alternative, for example as in the case of a third modification, which in Fig.As shown in Fig. 7, the main burner 6 may be divided into two burner sectors 20a and 20b by barrier walls 17a and 17g, and the fuel system 21 may include two sets of a main fuel system and a main flow control valve, individually corresponding to the two burner sectors 20a and 20b. In this modification, the control unit 30 controls the main flow control valves such that, when fuel is to be supplied to all burner sectors 20a and 20b, a difference in fuel flow rate occurs between the burner sector 20a and the burner sector 20b. Specifically, with respect to an average of the fuel flow rates of the burner sectors 20a and 20b, the fuel flow rate F2b of the burner sector 20b is increased, while the fuel flow rate F2a of the burner sector 20a is decreased. Consequently, combustion stability can be improved. Description of reference symbols 3 Combustion chamber device 5 preburners 6 main burners 20a to 20f burner sector 26 Flow pilot valve 27a to 27d Main flow control valve 30 Control unit

Claims

[1] Gas turbine combustor device (3) comprising: a preburner (5); a flow pilot valve (26) which regulates a flow rate of fuel to be supplied to the preburner (5); a premix combustion type main burner (6) disposed on an outer peripheral side of the preburner (5); a plurality of main flow control valves (27a, 27b, 27c, 27d) which regulate flow rates of fuel which is individually supplied to a plurality of burner sectors (20a to 20d; 20a to 20f; 20a, 20b) into which the main burner (6) is divided in a circumferential direction; and a control unit (30) configured to control the flow pilot valve (26) and the plurality of main flow control valves (27a, 27b, 27c, 27d), characterized by , that the control unit (30) controls the plurality of main flow control valves (27a, 27b, 27c, 27d) such that, when fuel is to be supplied to all of the plurality of burner sectors (20a to 20d; 20a to 20f; 20a, 20b), a fuel flow rate of at least one burner sector increases and a fuel flow rate of another burner sector or other burner sectors decreases with respect to an average value of the fuel flow rates of the plurality of burner sectors (20a to 20d; 20a to 20f; 20a, 20b), wherein a difference in the fuel flow rate occurs between the at least one burner sector and the other burner sector or the other burner sectors among the plurality of burner sectors (20a to 20d; 20a to 20f; 20a, 20b). [2] Gas turbine combustor device (3) according to claim 1, wherein the control unit (30) controls the plurality of main flow control valves (27a, 27b, 27c, 27d) such that, when fuel is supplied to all of the plurality of burner sectors (20a to 20d; 20a to 20f; 20a, 20b), each fuel flow rate of the plurality of burner sectors (20a to 20d; 20a to 20f; 20a, 20b) alternately increases and decreases in the circumferential direction with respect to an average value of the fuel flow rates of the plurality of burner sectors (20a to 20d; 20a to 20f; 20a, 20b).

Images