JP5592965B2 - Control method and control apparatus for lean fuel intake gas turbine - Google Patents

Description

  The present invention relates to a lean-fuel-intake gas turbine engine that uses low-calorie gas such as CMM (Coal Mine Methane) and VAM (Ventilation Air Methane) generated in a coal mine as fuel. The present invention relates to a method and apparatus for controlling.

  A lean-fuel intake gas turbine engine has been proposed in which CMM generated in a coal mine is mixed with VAM or air and sucked into the engine, and combustible components contained therein are burned in a catalytic combustor (for example, , See Patent Document 1). In a gas turbine using a catalytic combustor, when the intake air temperature is low, there is a possibility that the catalyst falls into an inactive state due to a decrease in the inlet temperature of the catalytic combustor, the combustor misfires, and operation cannot be maintained.

  As a control for preventing such a decrease in the inlet temperature of the catalyst combustor, in a gas turbine that uses a fuel having a predetermined concentration mixed with air, the supplied air flow rate and fuel flow rate are reduced to the catalyst pressure loss. A method of adjusting based on this has been proposed (for example, see Patent Document 2).

JP 2010-019247 A Japanese Patent Laid-Open No. 05-203151

  However, in the control in which the parameter is corrected based on the pressure loss of the catalyst, it is difficult to appropriately control the intake air temperature before the gas turbine engine is started or when the gas turbine engine is started. In addition, in a lean fuel intake gas turbine engine that uses CMM generated in a coal mine as fuel, the fuel concentration constantly fluctuates, so control is performed to directly increase the fuel flow rate when the inlet temperature of the catalytic combustor decreases. In such a case, the supply of methane, which is a combustion component, becomes excessive, and the catalyst may burn out.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a gas turbine engine control method and control capable of preventing misfiring of a catalytic combustor and stably maintaining an operating state even when the intake temperature of a lean fuel intake gas turbine engine is lowered. To provide an apparatus.

In order to achieve the above object, a control method or control device for a gas turbine engine according to the present invention comprises a catalytic combustor that burns compressed gas compressed by a compressor and supplies the compressed gas to the turbine, A method or apparatus for controlling a lean fuel intake gas turbine engine comprising a heat exchanger for heating the compressed gas using exhaust gas as a heating medium, and using a combustible component contained in low-concentration methane gas as fuel, When the temperature of the intake gas flowing into the compressor of the gas turbine engine is lower than a predetermined value, the engine speed is decreased according to the temperature of the intake gas. Specifically, the number of revolutions is controlled by lowering the number of revolutions of the generator via a power converter interposed between the generator driven by the gas turbine engine and the external power system .

  According to this configuration, the catalyst inlet temperature is maintained by controlling the rotational speed of the lean fuel intake gas turbine engine in accordance with the intake air temperature. The rotational speed control according to the intake air temperature, that is, the correction of the rotational speed command value can be performed not only during the rated operation of the gas turbine engine but also at the start time or before the start time. Misfire is reliably prevented, and the operating state of the gas turbine engine can be stably maintained.

  In the control method or control apparatus for a gas turbine engine according to an embodiment of the present invention, specifically, the rotation speed is controlled between a generator driven by the gas turbine engine and external power. It is preferable to carry out by lowering the rotational speed of the generator via a power converter. In a lean-fuel intake gas turbine engine, where the fuel concentration constantly fluctuates, if the rotational speed is controlled by adjusting the fuel flow rate, the catalytic combustor is likely to burn out or misfire, but the rotational speed should be controlled via a power converter. Thus, stable control can be realized.

  In the gas turbine engine control method or control device according to an embodiment of the present invention, the gas turbine engine is further configured to extract a compressed gas from the compressed gas passage to the exhaust gas passage, and the extraction passage. And a bleed valve for adjusting the flow rate of the bleed gas passing through the gas, and the inlet temperature of the combustor may be raised by increasing the degree of opening of the bleed valve. According to this configuration, when the intake air temperature is lowered, even if the inlet temperature of the catalytic combustor cannot be maintained even by the above-described rotation speed control, the inlet temperature of the combustor is reliably maintained, and the gas turbine engine Can be operated more stably.

  According to the control method and control apparatus for a gas turbine engine according to the present invention, even if the intake air temperature taken in by the engine is lowered, the misfire of the catalytic combustor is surely prevented and the operation state of the gas turbine engine is stabilized. Can be maintained.

It is a block diagram which shows schematic structure of the gas turbine engine which is the control object of the control method which concerns on one Embodiment of this invention. It is a block diagram which shows the control logic of the control method which concerns on one Embodiment of this invention.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram illustrating a gas turbine engine GT to be controlled by a control method according to an embodiment of the present invention. The gas turbine engine GT includes a compressor 1, a single can type main combustor 3, a turbine 5, and a heat exchanger 7. The generator 9 is driven by the output of the gas turbine engine GT.

  The gas turbine engine GT in the present embodiment mixes low calorie gas such as CMM (Coal Mine Methane) generated in a coal mine with air or VAM (Ventilation Air Methane) discharged from the coal mine. The main combustor 3 is configured as a catalytic combustor including a catalyst such as platinum or palladium. It is configured.

  As a low calorie gas used in the gas turbine engine GT, for example, a VAM generated in a coal mine and a fuel gas having two different fuel concentrations such as CMM having a higher combustible component (methane) concentration than that are mixed. 11 is introduced into the gas turbine engine GT from the intake port of the compressor 1. The mixer 11 is provided in the middle of the fuel introduction path 12 for introducing the CMM from the CMM fuel source into the compressor 1. Further, the flow rate of the CMM fuel is adjusted by a CMM fuel control valve 13 provided on the upstream side of the mixer 11 in the fuel introduction path 12. An intake air temperature measuring device T1 for measuring the temperature of the intake gas G1 is provided at the intake air inlet of the compressor 1.

  The intake gas G <b> 1 is compressed by the compressor 1, and the high-pressure compressed gas G <b> 2 is sent to the main combustor 3. The compressed gas G <b> 2 is combusted by a catalytic reaction by a catalyst such as platinum or palladium in the main combustor 3, and a high-temperature / high-pressure combustion gas G <b> 3 generated thereby is supplied to the turbine 5 to drive the turbine 5. An inlet temperature measuring device T2 and an outlet temperature measuring device T3 are provided at the inlet and the outlet of the main combustor 3, respectively.

  The turbine 5 is connected to the compressor 1 and the generator 9 via a rotating shaft 15, and the compressor 1 and the generator 9 are driven by the turbine 5. A rotation detector 18 that measures the number of rotations of the turbine 5 is provided in a portion of the rotating shaft 15 between the compressor 1 and the generator 9. The generator 9 is connected to an external power system 19 via a power conversion device 17. The power conversion device 17 incorporates a circuit that converts DC power and AC power into each other, and performs bidirectional power supply between the generator 9 and the power system 19.

  The heat exchanger 7 heats the compressed gas G2 introduced from the compressor 1 into the main combustor 3 using the turbine exhaust gas G4 from the turbine 5 as a heating medium. The compressed gas G2 from the compressor 1 is sent to the heat exchanger 7 through the compressed gas passage 21, heated here, and then sent to the main combustor 3 through the high-temperature compressed gas passage 25. Turbine exhaust gas G 4 that has passed through the main combustor 3 and the turbine 5 flows into the heat exchanger 7 through the turbine exhaust gas passage 29. The exhaust gas G5 flowing out from the heat exchanger 7 is silenced through a silencer (not shown) and then released to the outside.

  Further, the gas turbine engine GT has a bleed passage 31 that is branched from the compressed gas passage 21. The extraction passage 31 is connected to the exhaust gas passage 29, and part of the compressed gas G <b> 2 passing through the compressed gas passage 21 is extracted into the exhaust gas passage 29 as necessary. In the middle of the bleed passage 31, a bleed valve 33 that adjusts the flow rate of the compressed gas passing through the bleed passage 31 is provided.

  Although not shown, high-temperature combustion gas is supplied to the heat exchanger 7 downstream of the bleed valve 33 in the bleed passage 31 until the main combustor 3 reaches a predetermined operating temperature after the gas turbine engine GT is started. Then, an auxiliary combustor for warming up the heat exchanger 7 may be provided. In that case, the auxiliary combustor is supplied with fuel, for example, CMM, from a dedicated fuel supply path.

  When the temperature of the intake gas G1 flowing into the compressor 1 is lower than a predetermined value with respect to the gas turbine engine GT having such a configuration, the rotational speed of the gas turbine engine GT according to the temperature of the intake gas G1. A control device 41 is provided for reducing the above.

  A method for controlling the gas turbine engine GT by the control device 41 will be described in detail below. In the control method according to the present embodiment, as shown in FIG. 2, the rotation speed correction unit 43 provided in the control device 41 corrects the rotation speed based on the measurement result of the intake air temperature measuring device T1. Specifically, if the temperature of the intake gas G1 measured by the intake air temperature measuring device T1 is equal to or higher than a predetermined value, the rotational speed correction unit 43 does not correct the rotational speed command value and keeps the rated rotational speed, When the temperature of the intake gas G1 measured by the temperature measuring device T1 is lower than a predetermined value, the rotational speed command value is lowered according to the temperature measurement value of the intake gas G1.

  On the other hand, the rotational speed control unit 45 of the control device 41 receives the command value from the rotational speed correction unit 43 and controls the rotational speed of the generator 9 via the power conversion device 17, so that the gas turbine engine GT Control the number of revolutions. Specifically, a decrease in the rotational speed command value of the rotational speed control unit 45 is performed to decrease the rotational speed of the gas turbine engine GT, thereby preventing a decrease in the inlet temperature of the main combustor 3. When the rotational speed of the gas turbine engine GT is reduced, the intake amount of the intake gas G1 is reduced, and the fuel-air ratio in the main combustor 3 is increased. As a result, the outlet temperature of the main combustor 3 and the temperature of the turbine exhaust gas G4 are maintained, and the inlet temperature of the main combustor 3 heated via the heat exchanger 7 is also maintained.

  The control device 41 operates over the entire operation period when the gas turbine engine GT is started and during rated operation, and performs the above-described rotation speed correction according to the measured temperature of the intake gas G1. Furthermore, the control device 41 may be operated before starting (stopping) the gas turbine engine GT, and the rotational speed command value may be corrected according to the intake air temperature.

  Further, if the decrease in the inlet temperature of the main combustor 3 measured by the inlet temperature measuring device T2 cannot be suppressed even by the above rotation speed control, the catalyst inlet temperature controller 47 of the control device 41 opens the extraction valve 33. The inlet temperature of the main combustor 3 is increased by correcting the degree command value and increasing the opening degree of the extraction valve 33. By increasing the opening degree of the bleed valve 33 and reducing the flow rate of the compressed gas G2 flowing into the main combustor 3, the fuel-air ratio in the main combustor 3 further increases, and the outlet temperature of the main combustor 3 and The temperature of the turbine exhaust gas G4 is maintained, and the inlet temperature of the main combustor 3 heated through the heat exchanger 7 is maintained.

  By controlling the opening degree of the bleed valve 33 by the catalyst inlet temperature control section 47, even when the intake temperature is lowered, the inlet temperature of the catalytic main combustor 3 cannot be maintained even by the above-described rotation speed control. The inlet temperature of the main combustor 3 can be reliably maintained.

  As described above, in the gas turbine engine control method according to the present embodiment, the catalyst inlet temperature is maintained by controlling the rotational speed of the lean fuel intake gas turbine engine GT according to the intake air temperature. Therefore, misfiring due to a decrease in the intake air temperature of the catalytic main combustor 3 can be reliably prevented even during start-up, and the operation state of the gas turbine engine GT can be stably maintained.

  As described above, the preferred embodiments of the present invention have been described with reference to the drawings, but various additions, modifications, or deletions can be made without departing from the spirit of the present invention. Therefore, such a thing is also included in the scope of the present invention.

1 Compressor 3 Main combustor (catalytic combustor)
DESCRIPTION OF SYMBOLS 5 Turbine 7 Heat exchanger 9 Generator 17 Power converter 31 Extraction path 33 Extraction valve 41 Control apparatus 43 Rotation speed correction part 45 Rotation speed control part 47 Catalyst inlet temperature control part G1 Intake gas GT Gas turbine engine T1 Intake air temperature measurement device

Claims (6)

A catalytic combustor that burns compressed gas compressed by a compressor and supplies the turbine to a turbine, and a heat exchanger that heats the compressed gas using exhaust gas from the turbine as a heating medium, and is included in low-concentration methane gas A method for controlling a lean fuel intake gas turbine engine that uses a combustible component as a fuel,
Control of a lean fuel intake gas turbine engine that reduces the engine speed according to the temperature of the intake gas when the temperature of the intake gas flowing into the compressor of the gas turbine engine is lower than a predetermined value Method. The control method according to claim 1, wherein a power conversion device is interposed between a generator driven by the gas turbine engine and an external power system, and the rotational speed of the generator is reduced via the power conversion device. A control method for a lean-fuel-intake gas turbine engine that reduces the rotational speed of the engine. 3. The control method according to claim 1, further comprising: extracting a compressed gas from the compressed gas passage into the exhaust gas passage to the gas turbine engine, and a flow rate of the extracted gas passing through the extraction passage. 4. A control method for a lean-fuel- intake gas turbine engine that includes a bleed valve that adjusts the air flow rate and raises the inlet temperature of the combustor by increasing the opening of the bleed valve. A catalytic combustor that burns compressed gas compressed by a compressor and supplies the turbine to a turbine, and a heat exchanger that heats the compressed gas using exhaust gas from the turbine as a heating medium, and is included in low-concentration methane gas An apparatus for controlling a lean-fuel intake gas turbine engine that uses a combustible component as a fuel,
A lean fuel comprising a rotation speed correction unit that reduces a rotation speed command value of the engine according to the temperature of the intake gas when the temperature of the intake gas flowing into the compressor of the gas turbine engine is lower than a predetermined value Control device for intake gas turbine engine. 5. The control device according to claim 4, further comprising: a power converter interposed between a generator driven by the gas turbine engine and an external power system based on a rotational speed command value from the rotational speed correction unit. A lean-fuel- intake gas turbine engine control device comprising a rotation speed control unit that controls the rotation speed of the generator via an internal combustion engine. 6. The control device according to claim 4, wherein the gas turbine engine adjusts a bleed passage for extracting compressed gas from the compressed gas passage to the exhaust gas passage, and a flow rate of the bleed gas passing through the bleed passage. A lean fuel intake gas turbine engine, further comprising a catalyst inlet temperature control unit that raises the inlet temperature of the combustor by increasing the opening of the extraction valve. Control device.

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