JP2005248707A - Gas turbine combustion device, and control device and control method for gas turbine combustion device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent abrupt opening and closing of a flow control valve during switching control of a combustor. <P>SOLUTION: When exhaust gas temperature control is actuated during switching control of a combustor, the control device promptly stops the switching control of a combustor. Thereby, abrupt opening or closing of a flow control valve can be prevented, which leads to prevention of a service life loss and of an unstable control state of a gas turbine combustion device. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a two-stage combustion type gas turbine combustion apparatus including a first-stage combustion section, and a second-stage combustion section that is ignited using the first-stage combustion section as a fire type, and a control method thereof.

  As shown in FIG. 2, the gas turbine 1 includes an air compressor 2, a combustor 3, and a turbine unit 4. The gas turbine 1 introduces the compressed air 5 and fuel 6 compressed by the air compressor 2 to the combustor 3, mixes and burns them, and injects them as high-temperature and high-pressure combustion gas 7 to the turbine section 4. Rotating (working the combustion gas 7) to extract energy. In FIG. 2, 8 is a fuel mother pipe for supplying fuel, and 9 is a control device for the gas turbine combustion apparatus.

  In addition, the gas turbine 1 is connected to a generator 10 and used as a power generation device, for example, as shown in FIG. The rotation speed of the gas turbine 1 for power generation is determined by the AC frequency of the generator 10 and, for example, rotates at 3600 rpm at 60 Hz. In this case, the output of the generator 10 is determined by the output of the gas turbine 1, and the output of the gas turbine adjusts the flow rate of fuel supplied to the combustor 3 and the amount of air supplied from the air compressor 2 to the combustor 3. It is adjusted with.

  As a general combustor 3 used in the gas turbine 1, a two-stage combustion type combustion apparatus adopting a premixed combustion method which is the most environmentally friendly (low NOx) type is adopted. FIG. 3 shows a combustor 3 (two-stage combustion type low NOx combustion apparatus) adopting the premixed combustion method and its peripheral main part.

  As shown in FIG. 3, the combustor 3 includes a first-stage combustion section 21 disposed at the center of the combustion cylinder 20 and a second-stage combustion disposed around the first-stage combustion section 21. The unit 22 is configured. A transition piece 23 that sends combustion gas to the turbine section 4 is disposed at the tip of the combustion cylinder 20 in which the first-stage combustion section 21 and the second-stage combustion section 22 are disposed.

  A plurality of combustors 3 are arranged around the main shaft connected to the air compressor 2 and the turbine unit 4, and fuel is supplied to each combustor 3 by supplying fuel to the first stage combustion unit 21. This is performed via a first fuel manifold 26 and a second fuel manifold 27 that supplies fuel to the second stage combustion section 22. Fuel pressure control valves 30 and 31 and flow rate control valves 32 and 33 are attached to fuel supply lines 28 and 29 for supplying fuel from the fuel mother pipe 8 to the fuel manifolds 26 and 27, respectively.

  The compressed air 5 supplied from the air compressor 2 into the combustor 3 is circulated through the flow path 34 provided outside the combustion cylinder 20 and the transition piece 23, and is heated by heat exchange with the combustion gas during the circulation. Then, the fuel is burned together with the fuel supplied from the nozzles 24 and 25 of the combustion sections 21 and 22. An air amount adjusting valve 42 for adjusting the air amount is provided in the supply pipe 41 that sends the compressed air 5 from the air compressor 2 to the combustor 3.

  In the first stage combustion section 21 of the combustor 3, the compressed air 5 a supplied from the compressed air supply hole provided in front of the nozzle 24 of the first stage combustion section 21 and the fuel 6 a ejected from the nozzle 24 are mixed. Direct diffusion combustion is performed. On the other hand, in the second stage combustion section 22, a compressed air supply hole is provided on the base end side of the nozzle 25 of the second stage combustion section 22, and the combustion compressed air 5b and the fuel 6b ejected from the nozzle 25 are preliminarily supplied. Premixed combustion is performed in which the fuel is mixed and the mixed fuel is burned.

  The ignition operation of the second-stage combustion unit 22 is performed in a state where the first-stage combustion unit 21 is burning. As shown in FIG. 4, first, the pressure control valve 31 of the second fuel manifold 27 is opened, and the pressure A step 51 for fixing the opening degree of the control valve 31 to a constant, and a step 52 for gradually opening the flow control valve 33 of the second fuel manifold 27 after the pressure of the fuel in the second fuel manifold 27 is made constant. In the middle of the flow control valve 33 being fully opened, the second stage combustion section 22 is ignited with the first stage combustion section 21 igniting and ends 53. Thereafter, the flow proceeds to step 54 where the output of the gas turbine is adjusted by controlling the flow rate of the fuel supplied to the second stage combustion unit 22. The operation of igniting the second stage combustion unit 22 of the gas turbine combustion apparatus is called “combustor switching”, and the term “combustor switching” is also used in this specification as appropriate. Control of the operation for igniting 22 is referred to as “combustor switching control”.

  In the gas turbine combustion apparatus described above, when the temperature of the combustion gas 7 supplied to the turbine unit 4 is set, the heat resistance temperature of the turbine is taken into consideration and the temperature is set so as not to damage the turbine. For example, in the actual machine (Hitachi F7FA gas turbine (manufactured by General Electric)) used by the inventors, the temperature of the combustion gas 7 supplied to the turbine section 4 is set to 1418 ° C. In such a setting, since the temperature of the combustion gas 7 supplied to the turbine section 4 is too high, it cannot be directly measured. For this reason, the temperature of the combustion gas 7 supplied to the turbine unit 4 is indirectly measured by estimating from the outlet pressure of the air compressor 2 and the exhaust gas temperature 11 exhausted from the turbine unit 4. Note that the high-temperature and high-pressure combustion gas 7 supplied to the turbine unit 4 is discharged with both the pressure and the temperature decreased in the turbine unit 4 and the exhaust gas temperature is around 650 degrees, so that it can be measured.

  A plurality of the combustors 3 are arranged around the main shaft of the turbine unit 4, and the combustion gas 7 is supplied from the respective combustors 3 toward the turbine unit 4 at positions shifted in the circumferential direction, respectively. And the exhaust gas is exhausted to the rear of the turbine section 4. For this reason, a temperature sensor (not shown) for measuring the exhaust gas temperature 11 exhausted from the turbine unit 4 is provided behind the turbine unit 4 at positions shifted in the circumferential direction around the main shaft. As a result, when a malfunction occurs in any of the plurality of combustors 3 arranged around the main shaft, a significant difference occurs in the exhaust gas temperature measured between the temperature sensors. The malfunction of the combustor 3 can be detected. The average value of the exhaust gas temperature measured by each temperature sensor is used as the exhaust gas temperature of the turbine unit 4 when the temperature of the combustion gas is indirectly measured.

  The temperature of the combustion gas 7 is based on a curve S1 shown in FIG. 5 in which the relationship between the outlet pressure of the air compressor 2, the exhaust gas temperature 11 exhausted from the turbine section 4 and the temperature of the combustion gas 7 is theoretically obtained. Control. This curve S1 shows the relationship between the outlet pressure of the air compressor 2 and the exhaust gas temperature of the turbine unit 4 when the temperature of the combustion gas 7 supplied to the turbine unit 4 is set to a temperature that does not damage the turbine. . In consideration of the thermal efficiency, it is desirable to set the temperature of the combustion gas 7 supplied to the turbine unit 4 as high as possible. For this reason, in the step 54 of adjusting the output of the gas turbine, the fuel flow control valves 32 and 33 and the air flow rate are set so that the outlet pressure of the air compressor 2 and the exhaust gas temperature of the turbine section 4 are located on this curve S1. The adjustment valve 42 is adjusted.

  Adjustment of the flow rate control valves 32 and 33 and the air flow rate adjustment valve 42 is, for example, as shown in FIG. 6, the relationship between the outlet pressure 5 of the air compressor 2 and the exhaust gas temperature 11 of the turbine section 4 is a curve shown in FIG. It is determined 61 by determining whether or not it is above S1. When the determination 61 determines that the relationship between the outlet pressure 5 and the exhaust gas temperature 11 is higher than the curve S1, first, the air amount adjustment valve 42 is controlled to be opened 62. Then, again, it is determined whether or not the relationship between the outlet pressure 5 and the exhaust gas temperature 11 is above the curve S1, and in this determination 63, the relationship between the outlet pressure 5 and the exhaust gas temperature 11 is still above the curve S1. At this time, the flow control valves 32 and 33 are controlled to be throttled 64 this time. Further, when the relationship between the outlet pressure 5 and the exhaust gas temperature 11 is lower than the curve S1 in the first determination 61, control is performed so that the air amount adjustment valve 42 is throttled 65. Then, it is determined again whether or not the outlet pressure 5 and the exhaust gas temperature 11 are above the curve S1, 66. When the relationship between the outlet pressure 5 and the exhaust gas temperature 11 is still above the curve S1 in this determination 65, Next, the flow control valves 32 and 33 are controlled to be opened 67 (exhaust gas temperature control). This exhaust gas temperature control always operates 64 in a state where the second stage combustion unit 22 is combusting after switching the combustor, and functions in preference to the control of the combustor switching.

  Further, above the curve S1 shown in FIG. 5, when the combustion gas 7 becomes too high, the combustion in the first stage combustion section 21 and the second stage combustion section 22 is completely stopped in consideration of safety. A curve S2 is set for this purpose. As shown in FIG. 7, the control device 9 of the gas turbine combustion apparatus determines whether the relationship between the outlet pressure 5 of the air compressor 2 and the exhaust gas temperature 11 of the turbine section 4 exceeds this curve S2, 71 and exceeds it. When the flow rate is adjusted, the flow control valves 32 and 33 and the pressure control valves 30 and 31 are controlled to be closed 72 (exhaust gas temperature high trip control).

  Further, as shown in FIG. 8, the control device 9 of the gas turbine combustion apparatus is configured such that any one of the temperature sensors (not shown) provided around the turbine unit 4 is significantly more than the other temperature sensors. It is determined whether or not a low temperature or a significantly high temperature has been measured 81, and if the deviation of the temperature sensor that measures the exhaust gas temperature of the turbine section is greater than a predetermined deviation, it indicates some abnormality of the gas turbine combustion device Therefore, also in this case, the flow control valves 32 and 33 and the pressure control valves 30 and 31 are controlled to be closed 82 (exhaust gas temperature deviation control).

  Exhaust gas temperature deviation control and exhaust gas temperature high trip control function in preference to combustor switching control and exhaust gas temperature control, respectively.

The following patent documents can be cited as related to this kind of gas turbine combustion apparatus.
JP-A-8-135910

  During gas turbine combustor switching, in order to achieve complete ignition and stable combustion of the combustor, as described above, the pressure control valve, flow control valve, and combustion air regulator that send fuel are controlled by the operation program to perform the ignition operation. ing. As described above, the adjustment of the fuel to be supplied during the combustor switching is performed by first opening the pressure control valve 31 and increasing and fixing the pressure of the supplied fuel to a constant pressure, and then gradually adjusting the fuel flow control valve 32. It is to open.

  However, since priority is given to ensuring safety in the gas turbine combustion apparatus, even during such combustor switching control, exhaust gas temperature control (FIG. 6), exhaust gas temperature high trip control (FIG. 7), The exhaust gas temperature deviation control (FIG. 8) is activated with priority over the combustor switching control (FIG. 4).

  For this reason, even when the combustor is switched, if the combustion balance between the fuel and air sent to the combustor 3 deviates from a specified value during the ignition operation of the second stage combustor 22, the second stage combustor is forcibly used. The supply of fuel to 22 is stopped.

  As a specific event, there is a case where a defect has occurred in a pipe called a transition piece 23 that guides the combustion gas from the combustion units 21 and 22 to the turbine unit 4, and a problem has occurred in which the combustion gas leaks from the defective part to the outside. is assumed. In this case, the temperature of the combustion gas 7 that is actually supplied from the combustor 3 to the turbine unit 4 has not reached the specified temperature (1418 ° C. in the actual machine example), but leaked out of the transition piece 23. Due to the combustion gas, the exhaust gas temperature is measured high in the turbine section 4. In addition, due to problems such as a decrease in performance of the air compressor 2 and air leakage from the outer garment, the cooling air for the exhaust gas decreases and the exhaust gas temperature 7 rises.

  Hereinafter, events that occur when combustor switching control is performed in a situation where such a problem occurs will be described in time series based on the time series diagram shown in FIG. 9. In FIG. 9, L1 is the average value of the exhaust gas temperature of the turbine section, L2 is the control signal amount for fuel supply, L3 is the deviation of the exhaust gas temperature of the turbine section, L4 is the outlet pressure of the air compressor, L5 Indicates the opening of the pressure control valve in the second stage combustion section, L6 indicates the opening of the flow control valve in the second stage combustion section, L7 indicates the output of the gas turbine, and L8 indicates the opening of the air amount adjustment valve. Show. Refer to FIG. 3 for the pressure control valve 31, the flow control valve 33, and the air amount adjustment valve.

  When the combustor switching control is performed, as shown in FIG. 9, the opening L5 of the fuel pressure control valve 31 of the second stage combustion section 22 is fixed (A), and the second stage combustion section 22 The fuel flow control valve 33 is gradually opened (B), and the second stage combustion unit 22 is ignited while the flow control valve 33 is being opened (C). When the second stage combustion unit 22 is ignited, the combustion gas leaked outside from the transition piece 23 raises the average value L1 of the exhaust gas temperature of the turbine unit 4, and the outlet pressure of the air compressor 2 and the turbine unit 4 The exhaust gas temperature relationship exceeds the curve S1 in FIG. 5 (D).

  When the relationship between the outlet pressure of the air compressor 2 and the exhaust gas temperature of the turbine section 4 exceeds the curve S1, the exhaust gas temperature control shown in FIG. 6 is activated. This exhaust gas temperature control functions in preference to the combustor switching control. Therefore, the exhaust gas temperature control causes the pressure control valve 31 and the flow rate control valve 33 of the second stage combustion unit 22 to be rapidly throttled, and the air amount adjustment valve 42 for adjusting the supply amount of compressed air is opened (E). .

  When the pressure control valve 31 and the flow rate control valve 33 are rapidly throttled by the operation of the exhaust gas temperature control (E) and the air amount adjustment valve 42 is opened, the temperature of the combustion gas leaked to the outside from the transition piece 23 As a result, the exhaust gas temperature in the turbine section rapidly decreases (F). When the exhaust gas temperature (average value L1) falls to some extent, the exhaust gas temperature control is canceled and the combustor switching control starts to function again. At this time, since the second stage combustion unit 22 has ignited once at the time of (C), the opening signals of the pressure control valve 31 and the flow rate control valve 33 required by the control of the combustor switching are large, and the pressure control The valve 31 and the flow rate control valve 33 are each suddenly opened (G). When the pressure control valve 31 and the flow rate control valve 33 are suddenly opened, high-temperature combustion gas leaks from the combustor having a damaged transition piece 23, so that only a part of the temperature sensor that measures the exhaust gas temperature of the turbine unit 4 is used. Measure high temperature (H). For this reason, the exhaust gas temperature deviation control shown in FIG. 8 operates. The exhaust gas temperature deviation control functions in preference to the combustor switching control, is controlled to stop the combustor switching operation, and closes the pressure control valve 31 and the flow control valve 33 of the second stage combustion section (I ).

  Even when the ignition of the second-stage combustion unit 22 fails, the combustor switching control is once returned to the state where the first-stage combustion unit 21 is combusted, and after several tens of seconds, the combustor switching control is performed again. (J) (retry).

  In the second ignition operation (retry), since the exhaust gas temperature of the turbine section 4 has already been slightly higher in the first ignition operation, the exhaust gas temperature rapidly rises when the flow control valve 33 opens (K). . At this time, if the relationship between the outlet pressure of the air compressor 2 and the exhaust gas temperature of the turbine section 4 exceeds the curve S2 of FIG. 5, the exhaust gas temperature high trip control shown in FIG. 7 is activated. The exhaust gas temperature high trip control functions in preference to the combustor switching control and the exhaust gas temperature control. The flow control valve 33 and the pressure control valve 31 of the second stage combustion unit 22 are rapidly closed, and the air amount adjustment valve 42 is used. (L).

  When the ignition failure of the second stage combustion unit 22 occurs twice by the exhaust gas temperature high trip control, the combustor switching control stops the combustor switching operation and also stops the combustion operation of the first stage combustion unit 21. The gas turbine is put on standby for maintenance.

  As described above, in the control of the combustor switching for igniting the second stage combustion unit 22, even when the exhaust gas temperature of the turbine unit 4 becomes high due to some trouble, the exhaust gas temperature control (E) and the exhaust gas temperature deviation control (I ), Exhaust gas temperature high trip control (L) is functioning to ensure safety.

  However, in the current control described above, the exhaust gas temperature control (E), the exhaust gas temperature deviation control (I), and the exhaust gas temperature high trip control (L) are performed during the combustor switching control that ignites the second stage combustion unit 22. Sequentially function to open and close the pressure control valve 31 and the flow control valve 33 abruptly. For this reason, a rapid temperature change occurs in the gas turbine combustion device in a high temperature range, and the life of the gas turbine combustion device is advanced. Further, in the process of shifting from the exhaust gas temperature control to the combustor switching control, the flow rate control valve 33 is opened particularly rapidly as compared with the normal combustor switching control, so that the control is likely to be unstable. There is also a problem.

  At present, during the switching of the combustor, complete program control is performed, so it is impossible for the control person to intervene. As a result, the exhaust gas temperature is tripped as described above, or the control person judges. The combustor switching control itself is hand tripped (manual stop).

  The present invention controls the operation of igniting the second-stage combustion section by adjusting the flow rate of the fuel supplied to the second-stage combustion section while the first-stage combustion section is burning (in the above example, “ During the control of combustor switching "), a control (in the above example," exhaust gas temperature control ") that adjusts the flow rate of fuel supplied to the second stage combustion section based on the temperature of the combustion gas in the combustor was activated. In such a case, the ignition operation of the second stage combustion section is stopped.

  In the present invention, when the control for adjusting the flow rate of the fuel supplied to the second-stage combustion section is activated based on the temperature of the combustion gas of the combustor during the control for controlling the operation for igniting the second-stage combustion section. In addition, since the ignition operation of the second stage combustion unit is stopped, when some trouble occurs during the control of the combustor switching, the exhaust gas temperature of the turbine unit becomes high and the exhaust gas temperature control functions, the combustor switching is performed. Control is stopped. As a result, the flow rate control valve is not suddenly opened and closed, and a sudden temperature change can be prevented from occurring in the gas turbine combustion device in a high temperature range. Thereby, it is possible to prevent the life of the gas turbine combustion device from being advanced, and it is also possible to prevent the gas turbine combustion device from being in an unstable state in terms of control.

  Hereinafter, a gas turbine combustion apparatus and a control method thereof according to an embodiment of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected and demonstrated to the member and site | part which show | plays the same effect | action as the gas turbine combustion apparatus mentioned above.

  This control device is configured to stop the combustor switching control when the exhaust gas temperature control is activated during the conventional combustor switching control (in the case of E in FIG. 9).

  Specifically, as shown in the flowchart of FIG. 1, during the combustor switching control (first control) in which the opening degree of the pressure control valve 31 is fixed and the flow rate control valve 33 is opened, air A determination unit 101 that determines whether the relationship between the outlet pressure of the compressor 2 and the exhaust gas temperature of the turbine unit 4 is higher than the curve S1 in FIG. 5 and the exhaust gas temperature control (second control) is activated, and the determination unit , The processing unit 102 for stopping the combustor switching control for controlling the ignition operation of the second-stage combustion unit when it is determined that the exhaust gas temperature control is activated. This new control (third control) functions in preference to combustor switching control and exhaust gas temperature control.

  When this control is added to the combustor switching control, a malfunction occurs in the combustor and the exhaust gas temperature control is activated, that is, the combustor switching control is stopped immediately at the time point E in FIG. Thereby, exhaust gas temperature deviation control, exhaust gas temperature high trip control, etc. do not operate | move and the operation | movement by which a flow control valve is opened and closed rapidly can be prevented. As a result, the flow rate adjusting valve does not fall into a state where it is suddenly opened and closed, so that the life of the gas turbine combustion device can be prevented from progressing, and it can also be prevented from falling into an unstable state in terms of control.

  Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment.

The flowchart which shows the control of the combustor switching incorporating the new control which concerns on one Embodiment of this invention. Schematic which shows the whole structure of a gas turbine. The vertical side view which shows a combustor. The flowchart of control of combustor switching. The figure which shows the threshold value of exhaust gas temperature control. FIG. 3 is a flowchart of exhaust gas temperature control. Flow chart of exhaust gas temperature high trip control. The flowchart of exhaust gas temperature deviation control. The time series figure which shows the event which occurs when control of combustor switching is performed in the situation where the malfunction has occurred in the transition piece.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Gas turbine 2 Air compressor 3 Combustor 4 Turbine part 5 Compressed air 6 Fuel 7 Combustion gas 8 Fuel mother pipe 9 Control apparatus 10 Generator 11 Exhaust gas 20 Combustion cylinder 21 First stage combustion part 22 Second stage combustion part 23 Suction pieces 24, 25 Nozzles 26, 27 Fuel manifolds 28, 29 Fuel supply piping 30, 31 Pressure control valves 32, 33 Flow control valve 41 Supply piping 42 Air amount adjustment valve

Claims (3)

A combustor comprising a first stage combustion section and a second stage combustion section that is ignited using the first stage combustion section as a fire type;
A first control unit that controls an operation of igniting the second-stage combustion unit by adjusting a flow rate of fuel supplied to the second-stage combustion unit while the first-stage combustion unit is burning;
In the gas turbine combustion apparatus including the second control unit that adjusts the flow rate of the fuel supplied to the second stage combustion unit based on the temperature of the combustion gas of the combustor,
When the control for adjusting the flow rate of the fuel supplied to the second stage combustion unit by the second control unit is activated during the ignition operation control of the second stage combustion unit by the first control unit, the first control A gas turbine combustion apparatus comprising a third control unit that stops the ignition operation of the second-stage combustion unit by the unit. The gas turbine combustion apparatus includes a first stage combustion section and a second stage combustion section that is ignited using the first stage combustion section as a fire type,
A first control unit for controlling an operation of igniting the second stage combustion unit by adjusting a flow rate of fuel supplied to the second stage combustion unit in a state where the first stage combustion unit is burning;
In a control device for a gas turbine combustion apparatus comprising: a second control unit that adjusts a flow rate of fuel supplied to a second stage combustion unit based on a temperature of combustion gas of a combustor;
When the control for adjusting the flow rate of the fuel supplied to the second stage combustion unit by the second control unit is activated during the ignition operation control of the second stage combustion unit by the first control unit, the first control A control device for a gas turbine combustion device, comprising: a third control unit that stops the ignition operation of the second-stage combustion unit by the unit. In a control method of a gas turbine combustion apparatus comprising a first stage combustion section and a second stage combustion section ignited using the first stage combustion section as a fire type,
During the control of controlling the operation of igniting the second-stage combustion section by adjusting the flow rate of the fuel supplied to the second-stage combustion section while the first-stage combustion section is burning, the temperature of the combustion gas A control method for a gas turbine combustion apparatus, comprising: stopping an ignition operation of the second-stage combustion section when control for adjusting a flow rate of fuel supplied to the second-stage combustion section is activated based on