JP4684968B2 - High humidity gas turbine plant and control method thereof - Google Patents

Description

  The present invention relates to a high-humidity gas turbine plant having a turbine driven by combustion gas obtained by burning air containing moisture and fuel, and a control method therefor.

  A so-called high-humidity gas turbine is a system that uses a humidifier such as a humidification tower to add a large amount of moisture to combustion air, and then uses a regenerative heat exchanger to heat the exhaust gas from the combustion gas that drives the turbine. The turbine is driven by burning the air thus obtained together with the fuel, and the output and efficiency equivalent to or higher than that of the combined cycle can be obtained independently.

  In order to improve the output and efficiency of gas turbines, including these high-humidity gas turbines, the status of combustion in the combustion chamber (for example, load fluctuations, characteristics of the combustion target (humidity to the air, etc.), etc.) Accordingly, it is required to optimally control the temperature of the combustion gas. Further, the output of the gas turbine increases as the temperature of the combustion gas increases, but an upper limit value is determined for the temperature of the combustion gas from the viewpoint of protecting members exposed to the combustion gas (eg, combustor, turbine, etc.) from heat. It has been. Therefore, the control of the combustion gas temperature is required to improve the output and efficiency as much as possible without exceeding the upper limit.

  By the way, when controlling the combustion gas temperature, it is not generally performed to directly measure the temperature. This is because even if it is attempted to directly measure the combustion gas temperature, the temperature varies greatly depending on the measurement position, and it is difficult to measure the average temperature. Therefore, the combustion gas temperature is obtained indirectly based on the compressor outlet pressure detected by the detector, etc., and the exhaust temperature of the combustion gas, and output so that the indirectly obtained combustion gas temperature does not exceed the allowable value. The method of controlling is taken. And when adding water to combustion air like a high humidity turbine, and burning this with fuel and obtaining combustion gas, it is necessary to consider the humidification amount to combustion air, and the control method is Compared to the case where water is not added.

  Although the method of performing control according to the amount of water sprayed on the combustion air is not an example of application in a high-humidity gas turbine, a function that defines the set value of the exhaust temperature of the combustion gas by the outlet pressure of the compressor is used. Then, a correction is made according to the detection value of the water detector that detects the amount of water sprayed on the air, and the amount of fuel is adjusted so that the exhaust temperature during turbine operation is maintained at the set value obtained by this corrected function. Thus, there is a technique for controlling the combustion gas temperature indirectly (see Patent Document 1).

JP 61-286537 A

  However, the above technique is an indirect control method of the combustion gas temperature during rated load operation of a general gas turbine, and is a so-called non-control method such as when the load increases after starting a high-humidity gas turbine or during partial load operation. The following inconveniences occur when used during rated load operation.

  If the moisture content in the air decreases due to some factor (for example, failure of the humidification tower) during partial load operation, the exhaust temperature rises due to the decrease in latent heat. As countermeasures against the rise, only exhaust temperature control by adjusting the fuel supply amount can be performed. Therefore, there is a case where the output of the turbine is lowered due to the control for reducing the fuel supply amount in order to suppress the increase in the exhaust gas temperature accompanying the decrease in moisture. In addition, when the exhaust gas temperature is reduced as a result of controlling the exhaust gas temperature only by the fuel supply amount, the heating power of the regenerative heat exchanger is reduced, and the temperature of the air introduced into the combustor is lowered, resulting in the fuel The amount of use may increase. Thus, if the above technique is used during partial load operation of the high-humidity gas turbine, the efficiency of the plant is reduced. This impairs the characteristics of the high-humidity gas turbine that is more efficient during partial load operation than a general turbine.

  In addition, the humidification tower used for humidifying combustion air in a high-humidity gas turbine plant directly contacts the flowing water and the entire air to humidify all the way to saturation, and sprays like the above technique. Compared with the case of adding water, the humidification method is significantly different in that a large amount of humidification is performed. Therefore, the control method of the combustion gas temperature is also different, and the same control method cannot be applied as it is.

  An object of the present invention is to provide a high-humidity gas turbine plant excellent in output and efficiency during non-rated load operation and a control method thereof.

  (1) In order to achieve the above object, the present invention provides a turbine driven by combustion gas, a compressor that compresses combustion air, and a humidification tower that humidifies the air compressed by the compressor. A regenerative heat exchanger that heats the air humidified by the humidification tower by exhaust of the combustion gas that drives the turbine, and burns the air and fuel heated by the regenerative heat exchanger to A combustor for generating combustion gas to be driven; a compressor inlet guide vane for adjusting a flow rate of combustion air introduced into the compressor; and an outlet pressure of the compressor provided on an outlet side of the compressor A compressor outlet pressure detector for detecting the exhaust gas, an exhaust gas temperature detector for detecting the temperature of the exhaust gas provided in the exhaust flow path for driving the turbine, and an amount of water supplied to the humidification tower. Detected water supply A function corrected according to the amount of water supplied to the discharger and the humidifying tower, and a set value of the exhaust temperature for indirectly controlling the temperature of the combustion gas during partial load operation of the gas turbine. Using a function defined according to the outlet pressure of the compressor, the set value of the exhaust temperature is calculated from the outlet pressure detected by the compressor outlet pressure detector and the water supply amount detected by the water supply amount detector. A controller that calculates and adjusts the opening of the compressor inlet guide vane so that the exhaust temperature detected by the exhaust temperature detector approaches the calculated set value.

(2) Further, in order to achieve the above object, the present invention provides a turbine driven by combustion gas, a compressor that compresses combustion air, and a humidifier that humidifies the air compressed by the compressor. A tower, a regenerative heat exchanger that heats the air humidified by the humidifying tower by exhaust of combustion gas that has driven the turbine, and burns the air and fuel heated by the regenerative heat exchanger, A combustor that generates combustion gas for driving a turbine, a fuel control valve that adjusts the amount of fuel introduced into the combustor, and an outlet side of the compressor that detects an outlet pressure of the compressor Compressor outlet pressure detector, exhaust temperature detector provided in the exhaust flow path that drives the turbine and detecting the temperature of the exhaust, and correction depending on whether the humidification tower is operating Function Thus, the compressor outlet pressure is determined using a function that defines a set value of the exhaust temperature for indirectly controlling the temperature of the combustion gas when the load of the gas turbine rises, according to the outlet pressure of the compressor. A set value of the exhaust temperature is calculated from the outlet pressure detected by the detector and the amount of water supplied to the humidification tower, and the exhaust temperature detected by the exhaust temperature detector approaches the calculated set value. And a control device for adjusting the opening of the fuel control valve.

(3) The above (1) preferably includes a fuel adjustment valve that adjusts the amount of fuel introduced into the combustor, and the control device depends on whether or not the humidification tower is operating. Using a function that is corrected and that defines a set value of the exhaust temperature for indirectly controlling the temperature of the combustion gas when the load of the gas turbine increases, according to the outlet pressure of the compressor, A setting value of the exhaust temperature is calculated from the outlet pressure detected by the compressor outlet pressure detector and the amount of water supplied to the humidification tower, and the exhaust temperature detected by the exhaust temperature detector is the calculated setting. The opening degree of the fuel control valve is adjusted so as to approach the value.

(4) In the above (2) or (3), preferably, a function for indirectly controlling the temperature of the combustion gas at the time of increasing the load of the gas turbine is used before starting the humidification tower. function for pre-activation, and a function for after starting to use the after starting the said humidifying tower (5), wherein the control device, function and the humidifying tower (5) a function for after the activation for the pre-boot is A set value of the exhaust gas temperature is selected and used according to whether or not the engine is operating, and the fuel control valve is adjusted so that the exhaust gas temperature detected by the exhaust gas temperature detector approaches the calculated set value. The opening is to be adjusted.

  (5) Any of the above (1) to (4) is preferably provided with an intake sprayer provided on the upstream side in the air flow direction of the compressor and spraying water on the combustion air introduced into the compressor. It shall be provided.

(6) The present invention includes a turbine driven by combustion gas, a compressor that compresses combustion air, a humidifying tower that humidifies air compressed by the compressor, and a humidifier that is humidified by the humidifying tower. A regenerative heat exchanger that heats the heated air by exhaust of the combustion gas that has driven the turbine, and combustion that generates the combustion gas that drives the turbine by burning the air and fuel heated by the regenerative heat exchanger vessels and the control method of the compressor inlet guide vanes Ru and a gas turbine plant to adjust the flow rate of the air for combustion introduced into the compressor is corrected according to the amount of water supplied to the humidifying tower (5) a function, using the function defining according the set value of the exhaust temperature in order to indirectly control the temperature of the combustion gas during partial load operation of the gas turbine to the outlet pressure of the compressor, the pressure Wherein the amount of water supplied to the outlet pressure and the increase tower of the machine to calculate the set value of the exhaust temperature, the compressing said turbine so that the exhaust temperature of the combustion gas is driven approaches the set value the calculated The opening of the aircraft inlet guide vanes shall be adjusted.

(7) Further, the present invention provides a turbine driven by combustion gas, a compressor that compresses combustion air, a humidifying tower that humidifies air compressed by the compressor, and a humidifying tower. A regenerative heat exchanger that heats humidified air by exhausting the combustion gas that has driven the turbine, and generates combustion gas that drives the turbine by burning the air and fuel heated by the regenerative heat exchanger a combustor for a control method of the fuel control valve and the gas turbine plant Ru provided with adjusting the amount of fuel introduced into the combustor is adjusted in response to whether the up tower is running a function, using the function defining according the set value of the exhaust temperature in order to indirectly control the temperature of the combustion gas during the load increasing stage of the gas turbine to the outlet pressure of the compressor, the compressor Calculating the set value of the exhaust temperature from the outlet pressure, it is assumed that the exhaust gas temperature of the combustion gases by driving the turbines to adjust the opening degree of the fuel adjusting valve so as to approach the set value described above is calculated.

  According to the present invention, the combustion gas temperature during non-rated load operation in a high-humidity gas turbine plant can be appropriately controlled according to the situation, so that the output and efficiency during non-rated load operation can be improved. it can.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a system diagram of a high humidity gas turbine plant according to an embodiment of the present invention.
The high-humidity gas turbine plant shown in the figure is provided on the downstream side of the air flow direction from the turbine 1 driven by the combustion gas, the intake sprayer 2 that sprays water on the intake combustion air, Compressor 3 for compressing combustion air sprayed with water, humidifying tower 4 for humidifying the air compressed by compressor 3, and a humidifying tower 4 provided in a distribution path for exhaust of combustion gas. The regenerated heat exchanger 5 that heats the generated air by exhaust of the combustion gas that has driven the turbine 1, and the combustion gas that drives the turbine 1 is generated by burning the air and fuel heated by the regenerative heat exchanger 5. A combustor 6 to be operated, a fuel control valve 7 for adjusting the amount of fuel introduced into the combustor 6 according to the opening degree, and a combustion control valve provided upstream of the intake sprayer 2 in the air flow direction and introduced into the compressor 3 Air flow rate A compressor inlet guide vane 8 that is adjusted according to the opening degree, a compressor outlet pressure detector 9 that is provided on the outlet side of the compressor 3 and detects the outlet pressure of the compressor 3, and the combustion gas that has driven the turbine 1 An exhaust gas temperature detector 10 that detects the temperature of the exhaust gas provided in the exhaust gas flow path, and a water flow path that is provided in the water flow path supplied to the humidification tower 4, determines the amount of water supplied to the humidification tower 4. A water supply amount detector 11 to be detected and a control device 12 that sets a set value of the exhaust temperature of the combustion gas according to the state of combustion in the combustor 6 and controls the exhaust temperature according to the set value are mainly provided. ing.

  The rotating shaft (rotor) of the turbine 1 is connected to the generator 13, and the generator 13 generates electricity by the turbine 1 driven to rotate by the combustion gas. As shown in the figure, in the present embodiment, the turbine 1, the compressor 3, and the generator 13 are arranged on the same axis, but the arrangement of these three members is not limited to this. For example, from the viewpoint of generating power with the generator 13 by the driving force of the turbine 1, the compressor 3 may be arranged at a location different from the axis of the turbine 1 and the generator 13.

  The intake sprayer 2 sprays water on the combustion air introduced through the compressor inlet guide vanes 8. Although the supply source of the water to be sprayed is not particularly shown, for example, it may be configured to be connected to a water recovery device 18 (described later) for recovering water flowing through the plant and supply water therefrom. The water sprayed on the air partly evaporates and takes away the heat of the air, so the air is cooled. The cooled air increases in density and increases the weight flow rate when flowing into the compressor 3, thereby increasing the turbine output. Further, since the moisture in the air further evaporates due to the temperature rise due to compression in the compressor 3, the temperature of the compressed air at the outlet of the compressor 3 can be kept low. Accordingly, since the compression work of the compressor 3 is reduced, when the compressor 3 is driven by the driving force of the turbine 1 as in the present embodiment, the output of the gas turbine is further increased. Can do.

  The humidification tower 4 is provided at an upper portion thereof connected to a feed water heater 15 (described later), a water feed section 4 a into which water for humidifying the compressed air is introduced, and a feed water heater 15 at the lower portion of the humidification tower 4. A drainage portion 4b that is provided in a connected manner and discharges the water stored inside by humidifying the compressed air, and provided at the lower portion of the humidification tower 4 in connection with the compressor 3 and compressed by the compressor 3 The air supply part 4c into which compressed air is introduced, and the exhaust part 4d provided in the upper part of the humidification tower 4 by connecting with the regeneration heat exchanger 5 and exhausting the humidified air are provided.

  The humidifying tower 4 is started when the turbine output is increased to a predetermined value (for example, 50% load) during the transition from the turbine to the rated load operation after starting the turbine, and starts humidifying the combustion air. To do. The inside of the humidification tower 4 is filled with a packing such as a Raschig ring formed so as to increase its surface area. In this filling material, water introduced from the water supply unit 4a is sprinkled, and a water film is formed on the surface by the water flowing downward. The compressed air introduced from the air supply unit 4c passes through the packing in the process from the lower part to the upper part in the humidifying tower 4, and is humidified by directly contacting with the water flowing down there. In this way, the humidification method in which air and water are in direct contact with each other enables a large amount of humidification as compared with the case where steam or water is sprayed onto the air, and can humidify the combustion air to a saturated state. When a large amount of moisture is included in the combustion air in this way, the flow rate is increased by the amount of moisture and the turbine output is increased, and the specific heat of the mixed gas is increased by mixing water vapor having a specific heat higher than that of the combustion air. Therefore, the work that can be taken out when the mixed gas expands in the turbine 1 increases, and the turbine output further increases. Further, the water added to the air preferably has a high temperature so that it can be easily evaporated. In the plant of the present embodiment, water used for humidification in the humidifying tower 4 is heated in a feed water heater 15 (described later). Yes.

  The regenerative heat exchanger 5 is provided in the exhaust gas distribution path that drives the turbine 1, and preheats the air by exchanging heat between the air humidified in the humidification tower 4 and the exhaust. If the combustion air is preheated before being introduced into the combustor 6 in this way, the amount of fuel used in the combustor 6 can be reduced. Therefore, a plant in which the regenerative heat exchanger 5 is not installed (for example, a general The turbine efficiency is improved as compared with a gas turbine plant.

  The feed water heater 15 is disposed downstream of the regeneration heat exchanger 5 in the flow direction of the exhaust of the combustion gas, and heats water supplied from the humidification tower 4 by the feed water pump 16 with exhaust heat. The downstream side of the flow direction of the water heated by the exhaust heat is connected to the water supply unit 4a of the humidification tower 4, and a water amount control valve for adjusting the amount of water supply to the humidification tower 4 is connected to the water supply unit 4a. 14 is provided. A water recovery device 18 is provided further downstream from the feed water heater 15 in the exhaust circulation direction via a flue 17 that is an exhaust flow passage, and the exhaust gas is guided to the water recovery device 18.

  The water recovery device 18 cools the exhaust after heat exchange with the regenerative heat exchanger 5 and the feed water heater 15 with cold water, and collects and collects moisture contained in the exhaust by agglomerating and dropping. The water collected here is sent to the humidification tower 4 by the feed water pump 19 and used for humidifying the air. The exhaust cooling method employed in the present embodiment is a method in which the water stored in the water recovery device 18 is sent to the cooler 21 by the feed water pump 20, and the cooled water is sprayed to cool the exhaust. is there. The exhaust gas whose water has been recovered by the water recovery device 18 is discharged to the atmosphere via the chimney 22. The water released from the chimney 22 to the atmosphere is appropriately replenished from the water supply source to the water recovery device 18 by the water supply pump 23.

  The compressor outlet pressure detector 9 is provided on the outlet side of the compressor 3 and detects the outlet pressure of the compressor 3. The outlet pressure of the compressor 3 increases / decreases according to the operation state of the turbine, the increase / decrease of the amount of moisture added to the combustion air, and the change affects the exhaust gas temperature control.

  The water supply amount detector 11 is provided on the downstream side of the water amount adjustment valve 14 provided in the pipe line connecting the water supply heater 15 and the water supply unit 4 a of the humidification tower 4, and supplies water to the humidification tower 4. The amount is detected. As described above, the high-humidity gas turbine positively humidifies the entire combustion air in direct contact with water in the packing inside the humidifying tower 4, so that the humidification amount can be measured directly. difficult. Therefore, in this Embodiment, the amount of water supply to the humidification tower 4 is identified as the humidification amount to air, and the detected value of the water supply amount detector 11 is regarded as the humidification amount to air.

  The control device 12 is connected to the compressor outlet pressure detector 9, the exhaust gas temperature detector 10, and the water supply amount detector 11 to receive detection signals from these detectors 9, 10, 11, and fuel The control valve 7 and the compressor inlet guide vane 8 are connected, and an operation signal is appropriately transmitted to each of the adjusting means 7 and 8. The control device 12 performs the following control when transmitting operation signals to the fuel control valve 7 and the compressor inlet guide vanes 8.

  The control device 12 is a function that is corrected according to the amount of water supplied to the humidification tower 4, and compresses the set value of the exhaust temperature for indirectly controlling the combustion gas temperature during partial load operation of the gas turbine. The opening degree of the compressor inlet guide vane 8 is adjusted based on the partial load operation control function 30 defined according to the outlet pressure of the machine 3.

  FIG. 2 is a diagram showing the control function 30 during partial load operation of the high humidity gas turbine plant according to the embodiment of the present invention.

  The control function 30 is continuous with the parallel portion 31 extending in parallel with the horizontal axis from the vicinity of the vertical axis in the figure toward the direction in which the outlet pressure of the compressor 3 increases (the right direction in the figure), and the outlet 31 And a hatched portion 32 drawn so that the set value of the exhaust temperature decreases monotonously in the direction in which the pressure increases. This control function 30 is corrected by moving the position of the hatched portion 32 along the horizontal axis (in the horizontal direction in the figure) in accordance with the amount of water supplied to the humidification tower 4 detected by the water supply amount detector 11. Is done. Thereby, the control function 30 prevents the set value of the exhaust temperature from increasing or decreasing unnecessarily as the outlet pressure of the compressor 3 increases or decreases due to the increase or decrease of the amount of moisture in the combustion air.

  Here, the correction of the control function 30 will be described with a specific example. For example, when a stable operation is performed at a partial load, the amount of water supplied to the humidifying tower 4 decreases due to some factor (such as a failure of the water recovery device 18 or the humidifying tower 4), and the humidification amount to the combustion air suddenly increases. When it decreases, the control function 30 is corrected so that the shaded portion 32 translates in the negative direction (left direction in the figure) along the horizontal axis (corrected to the control line indicated by the dotted line in the figure). That is, the control function when the amount of water supply decreases is corrected so that the exhaust temperature is set lower when the exhaust temperature set by the function before correction is compared at the same outlet pressure. This prevents the outlet pressure of the compressor 3 from decreasing as the amount of moisture in the combustion air decreases, thereby preventing the set value of the gas turbine exhaust temperature from rising and exceeding the specified value, and the combustor 2 or the like. Can be protected from heat.

  On the contrary, when the amount of water supplied to the humidification tower 4 increases during the partial load operation, the hatched portion 32 moves in parallel along the horizontal axis in the positive direction (right direction in the figure). This prevents the gas turbine exhaust temperature from decreasing due to an increase in the outlet pressure of the compressor 3 as the amount of water in the combustion air increases, thereby reducing the efficiency of the gas turbine. The turbine can be used efficiently.

  The function shown above the control function 30 in the drawing is an exhaust temperature control function 50 used during rated load operation, and is controlled at an exhaust temperature higher than the control function 30 (for example, a temperature higher by about 5 degrees). Is set to

  The control device 12 performs the above correction on the control function 30 based on the water supply amount detected by the water supply amount detector 11, and the outlet detected by the compressor outlet pressure detector 9 using the corrected function 30. A set value of the exhaust temperature is calculated from the pressure, and the opening of the compressor inlet guide vane 8 is adjusted so that the exhaust temperature detected by the exhaust temperature detector 10 approaches the calculated set value, thereby indirectly setting the combustion gas temperature. Is controlling. That is, if the detected value of the exhaust temperature detector 10 is larger than the set value obtained from the control function 30, the opening of the compressor inlet guide vanes 8 is increased to increase the compressed intake flow rate, and if it is smaller than the set value, the compression is performed. The opening of the machine inlet guide vanes 8 is reduced to reduce the compressed intake flow rate.

  FIG. 3 is an explanatory diagram of the control used when the high humidity gas turbine plant according to the embodiment of the present invention reduces the load from the rated load operation.

  Here, point A shown in the figure is a point on the control function 50 used during rated load operation, and it is assumed that the combustion gas temperature is indirectly controlled at this point A during rated load operation. When shifting from this state to the partial load operation, first, the compressor inlet guide vanes 8 are kept at the same opening as the point A during the rated load operation, and the fuel control valve 7 is throttled to lower the load. Then, a transition is made to point B on the control function 30 used during partial load operation. In this case, the exhaust gas temperature decreases because the fuel supply amount is reduced with the same air flow rate. When the load is further reduced, the opening of the compressor inlet guide vane 8 is narrowed so that the exhaust temperature becomes on the control function 30 from the point when the point B is reached, and the point on the control function 30 is changed from the point B to the point C. And it is made to shift to D point in order. At the point D, the opening of the compressor inlet guide vane 8 is minimum, and in order to further reduce the load from the point D, it is necessary to throttle the fuel control valve 7, so that the set value of the exhaust temperature is from the point D to the E It will monotonously decrease to the point. In this way, by adjusting the opening of the compressor inlet guide vane 8 and changing the air flow rate so that the exhaust temperature is controlled on the control line 30, the exhaust temperature can be kept high even during partial load operation. Can do. Therefore, since the exchange heat quantity of the exhaust gas and the combustion air in the regenerative heat exchanger 5 can be kept high, the fuel consumption can be suppressed and the turbine efficiency can be improved. By using the control using the compressor inlet guide vanes 8, the power generation efficiency during partial load operation is improved by about 0.5 to 1.0% compared to the case where the control is not applied.

  On the other hand, the control device 12 is a function that is corrected according to the operating state of the humidification tower 4, and in the case where the turbine rotation speed becomes maximum after the gas turbine is started and the load is increased (when the load is increased). The opening degree of the fuel control valve 7 is adjusted based on a load increasing control function 40 that defines a set value of the exhaust temperature for indirectly controlling the combustion gas temperature according to the outlet pressure of the compressor 3. .

  FIG. 4 is a diagram illustrating the control function 40 when the load of the high humidity gas turbine plant according to the embodiment of the present invention is increased.

  In this embodiment, the control function 40 is a control function 40A for starting the humidification tower that is used before starting the humidification tower 4, and after the activation of the humidification tower that is used after starting the humidification tower 4. The control function 40B is composed of two types. The control function 40A is a function for indirectly controlling the combustion gas temperature in a state where the moisture by the humidification tower 4 is not contained in the combustion air, and the control function 40B is the function by which the humidity by the humidification tower 4 is the combustion air. This is a function for indirectly controlling the combustion gas temperature during rated load operation included in. The control function 40A has a parallel part 41a and a hatched part 42a similar to the control function 30, and similarly, the control function 40B has a parallel part 41b and a hatched part 42b. The control function 40B is corrected according to the amount of moisture added to the combustion air by the humidifying tower 4, and the hatched portion 42a of the control function 40A is positively directed along the horizontal axis according to the amount of moisture in the air ( The shape is translated in the right direction in FIG.

  The control device 12 selects the function 40A for before activation and the function 40B for after activation according to the operating state of the humidifying tower 4, and is detected by the compressor outlet pressure detector 9 using each function 40A, 40B. The exhaust gas set value is calculated from the outlet pressure, and the opening of the fuel control valve 7 is adjusted so that the exhaust temperature detected by the exhaust temperature detector 10 approaches the calculated set value, so that the combustion gas temperature is indirectly set. Is controlling. That is, if the detected value of the exhaust gas temperature detector 10 is larger than the set value obtained from the control function 40A or 40B, the opening amount of the fuel control valve 7 is decreased to decrease the fuel amount. The amount of fuel is increased by increasing the opening of the valve 7.

  After the turbine is started, the control device 12 operates as follows until the load is increased and transitioned to the rated load operation. The control device 12 starts the turbine and maximizes the number of revolutions thereof. After that, the humidifying tower 4 is stopped until the turbine load is increased from 0% to a set value (for example, 50%). The combustion gas temperature is indirectly controlled using the pre-start function 40A. Thereafter, when the turbine load rises to the set value, the humidification tower 4 is started and humidification of the combustion air is started. When humidification by the humidification tower 4 is started, the control device 12 changes the control function used for indirect control of the combustion gas temperature from the function 40A to the function 40B. Then, while performing indirect control of the combustion gas temperature based on the function 40B, the load is increased to 100% and shifted to the rated load operation.

  Next, the operation and effect of the present embodiment will be described.

  First, the operation and effect of control using the control function 30 during partial load operation will be described.

  FIG. 5 is a time chart showing the variation of each parameter during partial load operation of the high humidity gas turbine plant according to the embodiment of the present invention. Here, in order to facilitate understanding of the effects of the present invention, a comparative example will be described. In the comparative example used here, a correction value corresponding to the amount of moisture in the air is applied to a function that defines the setting value of the exhaust temperature of the combustion gas by the outlet pressure of the compressor, and the setting value obtained by this corrected function In this case, it is assumed that the method of indirectly controlling the combustion gas temperature by adjusting the amount of fuel so that the exhaust temperature during turbine operation is maintained is applied to a high-humidity gas turbine plant. A time chart is indicated by a dotted line 502 in FIG. On the other hand, a solid line 501 in the figure shows a time chart in the high humidity gas turbine plant according to the embodiment of the present invention.

  In the case of the comparative example shown in FIG. 5, when the humidification amount by the humidification tower decreases when the partial load operation is stably performed, the compressor outlet pressure decreases and the exhaust temperature increases due to the latent heat reduction. However, even if the compressor outlet pressure decreases, the control function is corrected to move the hatched portion of the function to the left in order to maintain the set value of the exhaust temperature in the same manner as before the decrease in the humidification amount. Based on the corrected control function, the control device performs control to decrease the exhaust gas temperature by decreasing the fuel supply amount, so that the exhaust temperature increase due to the decrease in the humidification amount is eliminated, and the exhaust temperature before the decrease in the humidification amount is restored. However, while the exhaust gas temperature recovers, the gas turbine output is greatly reduced due to the reduction of the humidification amount and the fuel supply amount. In addition, since there is a limit in controlling the exhaust temperature only by adjusting the fuel supply amount, the exhaust temperature may be lowered in some cases as compared to before the humidification amount is lowered. The problem of a decrease in exhaust temperature is a factor that further reduces turbine efficiency in a high-humidity gas turbine that includes a regenerative heat exchanger that uses exhaust heat and heats combustion air. This impairs the features of the high-humidity gas turbine, which is considered to be more efficient for partial load operation than a general gas turbine.

  In contrast to such a comparative example, the present embodiment is corrected in accordance with the water supply amount detector 11 that detects the amount of water supplied to the humidification tower 4 and the water supply amount to the humidification tower 4. Compression function using a control function 30 that defines a set value of the exhaust gas temperature according to the outlet pressure of the compressor 3 for indirectly controlling the temperature of the combustion gas during partial load operation of the gas turbine. A setting value for calculating the exhaust gas temperature from the outlet pressure detected by the machine outlet pressure detector 9 and the water supply amount detected by the water supply amount detector 11, and the exhaust temperature detected by the exhaust temperature detector 10 being calculated. And a control device 12 for adjusting the opening of the compressor inlet guide vane 8 so as to approach the value.

  With such a configuration, as shown in FIG. 5, even when the partial load operation is performed at a constant exhaust temperature, the opening degree of the compressor inlet guide vanes 8 is reduced even if the humidification amount by the humidification tower 4 is reduced. The exhaust gas temperature can be recovered to the value before the decrease in the humidification amount by increasing the compressor intake flow rate. Therefore, since it can drive | operate, hold | maintaining the amount of fuel supply, it can drive | operate, without reducing a turbine output. In addition, since the increase in the intake flow rate contributes to the increase in the turbine output, it is possible to cover the output decrease due to the decrease in the humidification amount.

  Further, in the present embodiment, the compressor intake flow rate is adjusted by the compressor inlet guide vanes 8, and it is possible to control to keep the exhaust temperature high even during partial load operation. Therefore, since the exchange heat quantity of the exhaust gas and the combustion air in the regenerative heat exchanger 5 can be kept high, the fuel consumption can be suppressed and the turbine efficiency can be improved. By using the control using the compressor inlet guide vanes 8, the power generation efficiency during partial load operation is improved by about 0.5 to 1.0% compared to the case where the control is not applied. In the above description, the effect when the humidification amount to the combustion air suddenly decreases has been mainly described. However, even when the humidification amount increases, the exhaust temperature can be maintained while suppressing the fuel supply amount. Turbine efficiency is improved.

  As described above, according to the present embodiment, the combustion gas temperature can be indirectly controlled appropriately even when the humidification amount by the humidification tower 4 changes during non-rated load operation. Efficiency can be improved.

  In the present embodiment, the amount of water supplied to the humidification tower 4 is identified as the amount of humidification to the air, and the detection value of the water supply amount detector 11 is used as the amount of humidification to the air. The approximate amount of water in the combustion air of the gas turbine can be measured. Thereby, since appropriate correction can be added to the control function 30 according to the change in the humidification amount, the exhaust temperature control suitable for the change in the humidification amount can be performed.

  Next, the operation and effect of control using the control function 40 when the load of the turbine is increased will be described.

  The humidification tower used for humidifying combustion air in a high-humidity gas turbine plant is to bring the flowing water and the entire air into direct contact and humidify all the way to saturation. The amount of water contained in is significantly different. Therefore, if a control method that corrects the control function according to the change in the detected value while detecting the amount of water absorption to the humidification tower as needed, the exhaust temperature control frequently operates, and the plant load operation performance is reduced. May fall.

  On the other hand, the present embodiment is a function that is corrected in accordance with the operating state of the fuel adjustment valve 7 that adjusts the amount of fuel introduced into the combustor 6 and the humidifying tower 4. Is detected by the compressor outlet pressure detector 9 using a function 40 that defines a set value of the exhaust temperature for indirectly controlling the temperature of the combustion gas when the load of the engine rises according to the outlet pressure of the compressor 3. A control device 12 for calculating a set value of the exhaust temperature from the outlet pressure and adjusting the opening of the fuel control valve 7 so that the exhaust temperature detected by the exhaust temperature detector 10 approaches the calculated set value. Yes.

  This makes it possible to determine the exhaust temperature setpoint using a control function that is optimally corrected for the combustion air whose humidification amount changes significantly when the load increases. Can do. In addition, since the exhaust temperature during the load increase can be kept high, the fuel consumption can be suppressed and the turbine efficiency can be further improved. Therefore, according to the present embodiment, the combustion gas temperature can be appropriately controlled even when the amount of humidification by the humidifying tower 4 changes when the load increases after the high-humidity gas turbine is started. Output and efficiency can be improved.

  In addition, although the control using the control function 30 and the control function 40 which were demonstrated above does not inhibit the effect even if it uses each separately, if it uses together, combustion at the time of non-rated load operation will be carried out. Since gas temperature control can be performed comprehensively, it exhibits an excellent effect compared to the case where it is used individually.

1 is a system diagram of a high humidity gas turbine plant according to an embodiment of the present invention. It is a figure showing the control function at the time of the partial load operation | movement of the high-humidity gas turbine plant which is embodiment of this invention. It is explanatory drawing of the control utilized when the high humidity gas turbine plant which is embodiment of this invention reduces load from rated load driving | operation. It is a figure showing the control function at the time of load increase of the high humidity gas turbine plant which is embodiment of this invention. It is a time chart which shows the change of each parameter at the time of partial load operation of the high humidity gas turbine plant which is an embodiment of the invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Turbine 2 Intake sprayer 3 Compressor 4 Humidification tower 5 Regenerative heat exchanger 6 Combustor 7 Fuel control valve 8 Compressor inlet guide vane 9 Compressor outlet pressure detector 10 Exhaust temperature detector 11 Water supply amount detector 12 Controller 18 Water recovery device 30 Partial load operation control function 31 Parallel portion 32 Shaded portion 50 Rated load operation control function 40 Load rising control function 40A Humidification tower pre-start control function 40B Humidification tower post-start control function 41a , B Parallel part 42a, b Shaded part

Claims (7)

A turbine driven by combustion gas;
A compressor for compressing combustion air;
A humidifying tower for humidifying the air compressed by the compressor;
A regenerative heat exchanger that heats the air humidified by the humidification tower by exhaust of combustion gas that has driven the turbine;
A combustor for combusting air and fuel heated by the regenerative heat exchanger to generate combustion gas for driving the turbine;
A compressor inlet guide vane for adjusting the flow rate of combustion air introduced into the compressor;
A compressor outlet pressure detector that is provided on the outlet side of the compressor and detects an outlet pressure of the compressor;
An exhaust gas temperature detector that is provided in a flow path of exhaust gas that drives the turbine and detects the temperature of the exhaust gas;
A water supply amount detector for detecting the amount of water supplied to the humidification tower;
A function that is corrected in accordance with the amount of water supplied to the humidification tower, wherein a set value of the exhaust temperature for indirectly controlling the temperature of the combustion gas during partial load operation of the gas turbine is Using a function defined according to the outlet pressure, the exhaust pressure set value is calculated from the outlet pressure detected by the compressor outlet pressure detector and the water supply amount detected by the water supply amount detector, A high-humidity gas turbine plant, comprising: a control device that adjusts an opening degree of the compressor inlet guide blade so that an exhaust temperature detected by an exhaust temperature detector approaches the calculated set value. A turbine driven by combustion gas;
A compressor for compressing combustion air;
A humidifying tower for humidifying the air compressed by the compressor;
A regenerative heat exchanger that heats the air humidified by the humidification tower by exhaust of combustion gas that has driven the turbine;
A combustor for combusting air and fuel heated by the regenerative heat exchanger to generate combustion gas for driving the turbine;
A fuel control valve for adjusting the amount of fuel introduced into the combustor;
A compressor outlet pressure detector that is provided on the outlet side of the compressor and detects an outlet pressure of the compressor;
An exhaust gas temperature detector that is provided in a flow path of exhaust gas that drives the turbine and detects the temperature of the exhaust gas;
A function that is corrected according to whether or not the humidification tower is in operation, and is configured to compress the set value of the exhaust temperature for indirectly controlling the temperature of the combustion gas when the load of the gas turbine increases. A set value of the exhaust temperature is calculated from the outlet pressure detected by the compressor outlet pressure detector using a function defined according to the outlet pressure of the machine, and the exhaust temperature detected by the exhaust temperature detector is calculated. A high-humidity gas turbine plant, comprising: a control device that adjusts an opening of the fuel control valve so as to approach the calculated set value. The high-humidity gas turbine plant according to claim 1,
A fuel control valve for adjusting the amount of fuel introduced into the combustor;
The control device is a function that is corrected according to whether or not the humidification tower is in operation, and is configured to control the temperature of the exhaust gas for indirectly controlling the temperature of the combustion gas when the load of the gas turbine increases. The exhaust temperature set value is calculated from the outlet pressure detected by the compressor outlet pressure detector using a function that defines the set value according to the compressor outlet pressure, and detected by the exhaust temperature detector. The high-humidity gas turbine plant is characterized in that the opening degree of the fuel control valve is adjusted so that the exhaust temperature thus obtained approaches the calculated set value. In the high-humidity gas turbine plant according to claim 2 or 3,
The function for indirectly controlling the temperature of the combustion gas when the load of the gas turbine is increased is a function for starting before starting the humidifying tower, and after starting the humidifying tower. This is a post-startup function to use,
The control device selects the pre-start function and the post-start function depending on whether or not the humidification tower is operating , and uses the selected function to detect the compressor outlet pressure. A set value of the exhaust temperature is calculated from the outlet pressure detected by the gas detector, and the opening of the fuel control valve is adjusted so that the exhaust temperature detected by the exhaust temperature detector approaches the calculated set value. A high-humidity gas turbine plant. In the high-humidity gas turbine plant according to any one of claims 1 to 4,
A high-humidity gas turbine plant comprising an intake sprayer that is provided upstream of the compressor in the air flow direction and sprays water onto combustion air introduced into the compressor. A turbine driven by combustion gas;
A compressor for compressing combustion air;
A humidifying tower for humidifying the air compressed by the compressor;
A regenerative heat exchanger that heats the air humidified by the humidification tower by exhaust of combustion gas that has driven the turbine;
A combustor for combusting air and fuel heated by the regenerative heat exchanger to generate combustion gas for driving the turbine;
A method of controlling a compressor inlet guide vane Ru and a gas turbine plant to adjust the flow rate of the air for combustion introduced into the compressor,
A function that is corrected in accordance with the amount of water supplied to the humidification tower, and a set value of the exhaust temperature for indirectly controlling the temperature of the combustion gas during partial load operation of the gas turbine is set at the outlet of the compressor. Using a function defined according to pressure, calculate a set value of the exhaust temperature from the outlet pressure of the compressor and the amount of water supplied to the humidification tower ,
A control method for a high-humidity gas turbine plant, wherein the opening degree of the compressor inlet guide vanes is adjusted so that the exhaust temperature of the combustion gas driving the turbine approaches the calculated set value. A turbine driven by combustion gas;
A compressor for compressing combustion air;
A humidifying tower for humidifying the air compressed by the compressor;
A regenerative heat exchanger that heats the air humidified by the humidification tower by exhaust of combustion gas that has driven the turbine;
A combustor for combusting air and fuel heated by the regenerative heat exchanger to generate combustion gas for driving the turbine;
A method for controlling a gas turbine plant Ru and a fuel control valve for adjusting the amount of fuel introduced into the combustor,
It is a function that is corrected according to whether or not the humidification tower is in operation, and a set value of the exhaust gas temperature for indirectly controlling the temperature of the combustion gas when the load of the gas turbine rises. Using the function defined according to the outlet pressure of the compressor , the set value of the exhaust temperature is calculated from the outlet pressure of the compressor ,
A control method for a high-humidity gas turbine plant, wherein the opening of the fuel control valve is adjusted so that the exhaust temperature of the combustion gas that drives the turbine approaches the calculated set value.

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