JP5142886B2 - Compressor - Google Patents

Description

  The present invention relates to a compressor and a control method thereof.

  Gas turbine compressor High-humidity gas turbine that improves the output and efficiency by adding moisture to the intake air and compressed working fluid to humidify, and recovering the thermal energy of the gas turbine exhaust gas by the humidified air The system is known. For example, in the gas turbine compressor described in International Publication No. 00 / 2,5009 pamphlet, the gas turbine output can be increased due to the intake air cooling effect of spraying droplets on the intake air to humidify. Further, there is an advantage that the droplet spray amount is increased and the droplets are introduced into the compressor, and the compression power can be reduced by the intermediate cooling effect, thereby improving the efficiency of the gas turbine. However, for a high-humidity gas turbine compressor that can improve the output and efficiency of the gas turbine by adding moisture to such a working fluid, the detection method for surging signs and the control method for avoiding surging are: Not mentioned.

  On the other hand, in a normal simple cycle gas turbine compressor, turning stall and surging are likely to occur on the front side of the compressor in the low speed range such as when starting up, and in the high speed range, the compressor stalls from the blade stage on the rear stage side. There is a tendency to rush into surging. As a method for detecting this surging, it is common to detect the surging by monitoring the intake air temperature of the compressor. Japanese Patent Laid-Open No. 2001-90555 discloses a technique for detecting surging by detecting the pressure and temperature at each stage in a compressor.

International Publication No. 00 / 2,5009 JP 2001-90555 A

In the case of an intercooler that sprays water, when spraying fine droplets to completely evaporate in the cooler, in order to suppress the precipitation of impurities from the droplets, It is desirable to use pure water from which impurities are removed to a very small amount. When impurities are deposited in the space in the cooler, the impurities may adhere to the inner wall of the cooler, or extremely small impurities may be introduced into the mainstream air and be brought into the compressor to damage the compressor. The object of the present invention is to prevent impurities from adhering to the inner wall of the cooling tower and flowing into the compressor without preparing pure water from which impurities have been removed to a very small amount. An object of the present invention is to provide a cooling device that can suppress a decrease in reliability of the machine .

In order to achieve the above object, an intermediate cooling mechanism of the present invention is a cooling device that is installed between stages of a gas compressor composed of a plurality of compression stages and cools a compressed gas of the compressor. The compressed gas is cooled by spraying the liquid, and for each droplet of the sprayed liquid, the water does not completely evaporate, and some of the droplets do not evaporate and remain in the liquid reservoir. And means for suppressing the liquid from flowing into the compression stage.

According to the present invention, it is possible to suppress the adhesion of impurities to the inner wall of the cooling tower and the inflow into the compressor without preparing pure water from which impurities are removed to a very small amount, thereby reducing the cooling efficiency of the cooling tower and the compressor. It is possible to provide a cooling device that can suppress a decrease in reliability .

  ADVANTAGE OF THE INVENTION According to this invention, the compressor which can avoid a surging effectively, and its control method can be provided.

  The high humidity utilization gas turbine system which is an Example of this invention is demonstrated using FIG. FIG. 7 is a system configuration diagram showing the overall configuration of a high-humidity utilization gas turbine system that is an embodiment of the present invention.

  The high humidity gas turbine includes a compressor 1, a combustor 2, a turbine 3, a regenerative heat exchanger 6, a humidifier 11, and an intake spray cooling device 12. The intake spray cooling device 12 sprays water 61 on the atmosphere 41 to generate moisture air 42. The moisture air 42 generated by the intake spray cooling device 12 is compressed by the compressor 1. The compressed air 43 generated by the compressor 1 is extracted at a full flow rate from the gas path outlet of the compressor. The high-pressure air 43 extracted from the gas path outlet of the compressor 1 is humidified by the humidifier 11. The humid air 44 humidified by the humidifier 11 is supplied to the regenerative heat exchanger 6 and is overheated by heat exchange with the exhaust gas 47 from the turbine 3. In the regenerative heat exchanger 6, the superheated moisture air 44 is supplied to the combustor 2 as moisture air 45. The moisture air 45 supplied to the combustor 2 is mixed and burned with the fuel 31. And the combustion gas 46 produced | generated by the combustor 2 is supplied to the turbine 3, and the turbine 3 is rotationally driven. The exhaust gas 47 discharged from the turbine 3 is heat-recovered by heat exchange with the moisture air 44 in the regenerative heat exchanger 6 and discharged as exhaust gas 52. The compressor 1 and the turbine 3 are connected by an intermediate shaft, and a generator 4 that converts shaft power generated by the turbine 3 into electric power is also connected to the rotating shaft of the compressor 1.

  The high-humidity-utilizing gas turbine that is an embodiment of the present invention can recover the thermal energy of the exhaust gas 47 into the combustion air in the regenerative heat exchanger 6 as compared with a normal simple cycle gas turbine. Therefore, the flow rate of the fuel supplied to the combustor 2 can be reduced, and the efficiency of the gas turbine cycle can be improved. Moreover, the output can be increased by increasing the working fluid by adding moisture with the humidifier 11. Furthermore, the heat recovery amount in the regenerative heat exchanger 6 can be increased by the effect of lowering the temperature of the working fluid by adding moisture and the effect of increasing the flow rate, and the efficiency of the gas turbine can be improved.

  Next, the moisture addition schedule of the high-humidity utilization gas turbine according to the embodiment of the present invention will be described with reference to FIG. FIG. 8 shows the relationship between the operation schedule, the rotational speed, and the output of the high humidity gas turbine according to the embodiment of the present invention. After starting the gas turbine, after the rotational speed reaches 100%, that is, when the rated rotational speed is reached, the fuel is supplied and the flow rate is increased to increase the volume flow rate of the hot gas flowing into the turbine 3 to increase the output and compressor. Is increased (step I). At this time, water is not supplied to the intake spray cooling device 12 and the humidifying device 11, and the rotation speed of the gas turbine is kept constant. In the present embodiment, the operating pressure ratio of the compressor 1 means the ratio of the inlet pressure of the turbine 3 to the outlet pressure of the turbine 3 that is atmospheric pressure.

  After the output of the gas turbine reaches a preset output value, water 62 is supplied to the humidifier 11 to increase the output of the gas turbine (stage II). As the output increases, the operating pressure ratio of the compressor 1 also increases. At this time, since the flow rate flowing into the turbine 3 increases due to humidification, the rotational speed is controlled to be kept constant while adjusting the flow rate of the fuel 31 supplied to the combustor 2. This is because the devices constituting the gas turbine are set so that the optimum operation is performed at the rated rotational speed.

  After the flow rate of the humid air 44 supplied with the water 62 by the humidifier 11 is stabilized, the supply of the water 61 to the intake spray cooling device 12 is started. Then, the gas turbine output further increases (stage III). The water 61 is supplied so that the output of the gas turbine reaches a preset output value in consideration of the atmospheric temperature. As the output increases, the intake air flow rate and the operating pressure ratio of the compressor 1 also increase. At this time, the flow rate of the air 43 discharged from the compressor 1 increases. On the other hand, the rotational speed is controlled to be constant by reducing the fuel flow rate 31 supplied to the combustor 2.

  When such a moisture addition schedule is not adopted and the high humidity gas turbine is operated at a partial rotational speed, that is, before the rated rotational speed is reached, water 41 is supplied to the intake air of the compressor 1. The blade load on the rear stage side of the compressor 1 may increase and the surge margin may decrease. Further, the amount of water 62 supplied to the humidifying device 11 is larger than that of water 61 supplied to the intake spray cooling device 12. Since the amount of increase in the operating pressure ratio of the compressor 1 due to the addition of moisture by the intake air cooling device 12 is larger than the amount of increase by the addition of moisture by the humidification device 11, the intake spray cooling device 12 Humidification with the humidifier 11 has a greater influence on the entire system than humidification. The rate of decrease of the surge margin is also large, and there is a possibility of surging at once. Therefore, it is necessary to supply water to the humidifier 11 before the intake spray cooler 12.

  If water is supplied to the intake spray cooling device 12 prior to water supply to the humidifier 11, the amount of humidification added to the working fluid is small, and the combustion temperature cannot be raised during partial load operation of the gas turbine. As a result, the amount of heat recovered in the regenerative heat exchanger 6 is reduced, and the efficiency of the gas turbine becomes lower than when moisture is added by the humidifier 11. The amount of water supplied to the intake spray cooling device 12 is also affected by the output command value and the atmospheric temperature. Therefore, it is desirable that the supply of the water 61 to the intake spray cooling device 12 is used for the last increase in output and efficiency improvement at the start of the gas turbine.

Example 1
A surging detection method for a gas turbine compressor, which is Embodiment 1 of the present invention, will be described with reference to FIG. FIG. 1 is a cross-sectional view showing an upper half of a flow path of a compressor 1 of a gas turbine that is Embodiment 1 of the present invention.

  A compressor 1 of a gas turbine that is Embodiment 1 of the present invention is an axial compressor that includes an intake spray cooling device 12. The intake spray cooling device 12 lowers the temperature of the working fluid inside the compressor 1 by spraying fine droplets at the working fluid inlet and evaporating it in the compressor flow path. Is a multi-stage compressor having a plurality of stages of stationary blades and moving blades. In FIG. 1, some of the intermediate stage stationary blades and moving blades are omitted. And the compressor flow path which abbreviate | omitted the stationary blade and the moving blade is described with a dotted line. The compressor 1 is provided between the compressor rotor that rotates on the same rotation shaft as the turbine 3, the moving blade 71 that is implanted in the rotating compressor rotor, and the axially front and rear of the moving blade 71. And a stationary blade 72 fixed to the casing 73. The flow path of the compressor 1 through which the air 42 as the working fluid passes is formed by a flow path inner surface 81 that is the outer peripheral surface of the compressor rotor and a flow path outer surface 82 that is the inner peripheral surface of the casing. In addition, the casing 73 has a bleed structure by the slit 91 and the bleed hole 92, and the stationary blade 72 on the front stage side of the compressor 1 has a blade angle in order to prevent turning stall at startup and to ensure a surge margin. An inlet guide vane 101 which is a variable mechanism is provided.

  Next, the flow of the working fluid will be described. The compressor 1 sucks air 41 from the atmosphere. Water 61 is sprayed onto the air 41 supplied from the atmosphere to the compressor 1 by the intake spray cooling device 12. The spray water 61 is pressurized by the high-pressure pump 67, adjusted to a predetermined flow rate by the flow control valve 63, refined by the spray nozzle in the intake spray cooling device 12, and sprayed on the air 41. Some of the fine droplets evaporate before being sucked into the compressor 1. This latent heat of vaporization can reduce the temperature of the working fluid. The intake air can be obtained at a lower temperature and higher density than the atmosphere, and the output of the gas turbine can be increased. Since the compressor intake air flow rate (mass flow rate) can be increased (the larger intake air cooling effect is obtained) as the atmospheric temperature is higher, by using the intake air spray cooling device 12, it is possible to prevent atmospheric temperature fluctuations throughout the year. The fluctuation of the gas turbine output can be suppressed. On the other hand, of the fine droplets, the droplets that could not be evaporated before flowing into the compressor 1 flow into the compressor as droplets. Inside the compressor 1, the liquid droplets evaporate while passing between the moving blades and between the stationary blades, and the temperature of the working fluid during compression is lowered. Since the compression characteristic approaches the isothermal compression due to the intermediate cooling effect, the power of the compressor 1 is reduced. As a result, the efficiency of the gas turbine is improved. The droplets introduced into the compressor are completely evaporated before the compressor is discharged. The working fluid is discharged from the compressor discharge.

  The characteristic of the compressor 1 of a present Example is demonstrated using FIG. In FIG. 2, the stage load distribution of the compressor 1 of the gas turbine which is an Example of this invention is shown. The horizontal axis indicates the position (number of stages) in the rotation axis direction, and the vertical axis indicates the magnitude of the stage load at each stage. The compressor 1 of this embodiment is a type of compressor that sprays droplets on the intake air 41 and completes evaporation of the sprayed water inside the compressor. In such a compressor, due to the intermediate cooling effect of the compressor, the stage load is reduced in the front stage cascade of the compressor 1, and the stage load is increased in the rear stage cascade. In this embodiment, the position in the rotation axis direction where the evaporation of the droplet is completed is referred to as the evaporation completion position. The front and rear blade rows of the compressor are determined on the front side or the rear side from the evaporation completion position.

  FIG. 2 (a) shows the stage load distribution of a compressor, such as a simple cycle gas turbine compressor, designed to operate optimally when droplets are not sprayed into the intake air of the compressor. Fig. 2 (b) is designed to operate optimally when droplets are sprayed into the intake air of a compressor, such as a high-humidity gas turbine, and the evaporation of the droplets is completed inside the compressor. The stage load distribution of a compressor is shown. In each case, the step load when the compressor 1 is operated by spraying water on the intake air is indicated by a solid line, and the step load when operated without the water spray is indicated by a dotted line. The position in the rotation axis direction where the solid line and the dotted line intersect is the evaporation completion position.

  For example, in the compressor shown in FIG. 2 (a) designed for operation without water spray, stall and choke are less likely to occur in operation without water spray, and all stages of cascades are rated at the rated speed. Designed to operate efficiently. Specifically, it is designed to have a load distribution with a certain margin from the boundary between the stall area on the high load side and the choke area on the low load side, which is indicated by a dashed line in FIG. In the compressor shown in FIG. 2 (b) designed for operation with water spray, in the operation with water spray, the constant is determined from the boundary between the stall area on the high load side and the choke area on the low load side. It is designed to have a load distribution with a margin.

  When the step load reaches the choke zone, the possibility of separation on the blade row pressure surface side increases. When the step load reaches the stall region, the possibility that separation occurs on the blade suction side increases. When peeling occurs, performance such as the pressure ratio and efficiency of the compressor 1 deteriorates. In particular, when the step load reaches the stall region and separation occurs on the blade row suction surface side, a turning stall may occur during startup, which may lead to surging. Surging is a phenomenon in which the operation becomes unstable as the pressure ratio is increased, causing pressure with a strong sound suddenly at a certain pressure ratio, intense pulsation of the flow and vibration of the machine. Increasing the margin of the stage load with respect to the stall leads to an increase in the surge margin, which is the margin of surging.

  The stage load distribution of the compressor shown in FIG. 2 (a) is, as shown by the dotted line in FIG. 2 (a), a margin for stall during rated load operation by lowering the stage load on the rear stage compared to the front stage. Degree, that is, a surge margin can be secured. When droplets are sprayed on the compressor designed in this way, due to the intermediate cooling effect, as shown by the solid line in FIG. 2 (a), the stage load decreases on the upstream side from the evaporation completion position, and on the downstream side, the stage load decreases. The load increases. If so, the possibility of stalling in the rear blade row increases, that is, the surge margin decreases, and the risk of entering surging increases. In particular, when a large amount of liquid droplets is supplied to the intake spray cooling device 12, the degree of reduction of the surge margin increases.

  Therefore, as the compressor for spraying droplets on the intake air, it is desirable to use a compressor that can perform optimum operation when the water intake is sprayed with water as shown in FIG. That is, from the load distribution shown by the dotted line in FIG. 2 (a), the stage of the rear stage blade row is preliminarily secured so that a sufficient surge margin can be secured even if the stage load of the rear stage blade row increases when droplets are sprayed. It is desirable that the load be set low and the stage load of the front stage blade row be set high so that the load distribution shown by the dotted line in FIG.

  For example, if the amount of droplets sprayed on the intake air of the compressor 1 is within about 2.0 wt% with respect to the operating flow rate, the droplets are almost evaporated by the inlet of the compressor 1. In this case, the necessity for changing the stage load distribution of the simple cycle gas turbine compressor 1 is low. When the amount of sprayed droplets is 2.0 wt% or more, the necessity of design in consideration of stage load distribution becomes high. In the high-humidity-utilizing gas turbine, the effect of reducing the compression power and improving the gas turbine efficiency is increased by increasing the spray amount.

  Next, the detection of the surging of the compressor shown in FIG. 2B designed in consideration of the spray of droplets on the compressor intake air will be described.

  Since the compressor 1 designed in consideration of spraying a large amount of droplets is designed so that the stage load on the rear stage side is reduced and the operating range of the blade row is on the choke side, the dotted line in FIG. When the intake spray cooling device 12 as shown is operated, the choke is caused in the rear stage blade row, the front stage blade row is stalled, and depending on the operation state, the turning stall is generated in the low rotation speed range. Is likely to attract surging. In the compressor 1 of the present embodiment, when the droplets are not sprayed by the intake air, the last stage blade row is most likely to choke, particularly during low speed operation such as at the time of startup. When choke occurs here, separation occurs on the pressure surface side of the last stage cascade. This stall on the pressure surface side spreads over the entire circumferential cascade and the flow is blocked. As a result, the rear side has a larger flow resistance than the front side, and the flow rate is reduced.

  FIG. 9 shows the characteristics of the flow coefficient and stage load coefficient of the last stage cascade and the upstream stage cascade. In a compressor designed for no water spraying, the operating point is (B) when choked in the final stage at a low rotational speed such as at the time of startup with respect to the rated operating point (A). When choking at the rear stage, the operating point changes to the stall side (B) at the front stage due to the decrease in flow rate.

  In the compressor designed in consideration of water spraying, as shown in FIG. 2B, the load on the rear stage side is designed to be on the choke side. Therefore, when choking in the final stage during low-speed operation such as startup at the rated operating point (A), the operating point of the last stage blade row is (C), that is, the choke side operates. . In this case, the operating point of the blade stage on the front side is further on the stall side (C), and there is a possibility that the stall limit is reached particularly when the atmospheric temperature is low.

  FIG. 10 shows the inlet temperature of each stage of the compressor 1. In a compressor designed without water spray, the inlet temperature of each stage increases almost linearly (T01⇒T02⇒T03) up to the compressor outlet with respect to the position in the rotational axis direction. However, when choking is performed on the rear stage side, the stage load increases on the upstream side of the choked stage and the stall side operation is performed. Then, the inlet temperature of each stage rises and the temperature distribution becomes T01⇒T2⇒T03. In a compressor designed in consideration of water spraying, the possibility of choking in the last stage blade row is most likely, so measurement of the temperature T2 upstream of the last stage blade is effective. Specifically, for example, the temperature Tcr before the final stage blade row when the front stage blade row reaches the stall limit is set, and monitoring is performed so that the upstream side temperature T2 of the last stage blade can be operated at Tcr or less. This is effective in avoiding surging. Note that the temperature rise due to the choke does not appear remarkably on the downstream side (compressor outlet side) of the last stage blade row, so it is effective to monitor the temperature upstream of the last stage blade.

  Also, there is almost no temperature rise at the inlet / outlet of the choked stage, and when measuring the temperature T2 upstream of the last stage rotor blade and the temperature T03 downstream of the last stage blade row, the temperature change amount is monitored. It is also possible to detect the choke sign of the cascade.

  Therefore, in the compressor 1 of the present embodiment, the temperature sensor 201 that detects the temperature in the working flow path upstream of the final stage moving blade 74 is disposed. By monitoring the temperature rise due to the choke in the last stage blade row, it is possible to predict the occurrence of surging due to the stall of the front blade row of the compressor 1.

  FIG. 11 is a cross-sectional view of the AA cross section of FIG. 2 as viewed from the upstream side of the compressor. The temperature sensor has a structure in which at least two points are measured in the circumferential direction with respect to the rotation axis, and the temperature sensing part at the tip of the temperature sensor is introduced into the mainstream air. When the tip of the temperature sensor is too close to the casing, an error may occur in the measurement of the mainstream air temperature due to the influence of the metal temperature of the casing. In the compressor of the present embodiment, temperature monitoring uses an average value of temperatures measured by two temperature sensors in the circumferential direction.

  As in this embodiment, surging can be avoided in advance by predicting surging by monitoring the temperature rise due to the choke in the rear stage cascade of the compressor 1. In this way, it is possible to improve the reliability of the compressor as compared with a method in which occurrence of a surging is detected by monitoring the temperature rise due to pressure fluctuation or blade load increase by detecting the occurrence of stall in the blade row.

  In the present embodiment, a multistage axial compressor is cited as an example, but the present invention can be similarly applied to any multistage compressor having two or more stages such as a multistage centrifugal compressor. Further, in this embodiment, the compressor that includes the intake spray cooling device 12 at the inlet of the compressor 1 and sprays the droplets is described. However, the compressor that sprays the droplets inside the compressor, or the middle of the compressor Any compressor having an intermediate cooling effect that lowers the temperature of the working fluid through the cooler in the stage can be applied.

  The multi-stage compressor of the present embodiment measures an intermediate cooling mechanism that cools the working fluid being compressed, and the temperature of the fluid cooled by the intermediate cooling mechanism on the upstream side in the axial direction from the final stage moving blade. It has temperature measuring means. This configuration is a configuration that takes into account the stage load distribution of the compressor provided with the intermediate cooling device. In such a compressor, by monitoring the upstream temperature of the compressor last stage blade cascade, it is possible to predict surging due to stall of the front stage blade row through detection of choke signs in the rear stage blade row, and the occurrence of surging Can be effectively avoided. In addition, surging can be predicted by monitoring the minimum necessary temperature sensor, so that the complexity of the control and measuring device can be suppressed, and the cost reduction and the ease of monitoring are also effective.

  Here, the case where the compressor 1 designed on the assumption of water spraying is operated without water spraying will be described. When the gas turbine is started, the temperature inside the compressor is low, so even if droplets are sprayed on the intake air, they are hardly evaporated and discharged as a drain. When the droplets cannot be completely evaporated inside the compressor, for example, in a gas turbine in which the discharge air of the compressor is introduced into the combustor 2, the droplets adhere to the combustor 2 and local thermal stress. May occur. Therefore, when droplets are sprayed on the intake air of the compressor 1, it is necessary to spray when the gas turbine is almost stabilized at the rated load operation. In this case, the compressor 1 is likely to continue to operate at the partial pressure ratio until the intake spray cooling device 12 is operated. Further, when the atmospheric temperature is low, icing, which is a phenomenon in which some of the droplets sprayed by intake air are solidified, may enter surging depending on the operating conditions. In such a case, it is conceivable to operate the gas turbine for a long time in a dry state where no intake air spray is performed.

  Stages I and II shown in FIG. 8 are also cases where no moisture is added by the intake spray cooling device 12. Since the operating pressure ratio of the compressor 1 increases as the gas turbine output increases, the operating point of the compressor 1 moves further to the stall side and surging side.

  In addition, the spraying of the droplets at the time of start-up may not always distribute the droplets sprayed uniformly due to the circumferential deviation of the flow at the compressor inlet, but may have a flow deviation in the circumferential direction. If the flow becomes uneven in the circumferential direction in this way, surging occurs and the possibility of entering an abnormal situation increases. When droplets are sprayed on the intake air of the compressor during partial rotation speed operation when the gas turbine is started, the load on the rear blade row increases and the possibility of causing surging increases. From this reason, it can be seen that there is a high need for countermeasures for surging.

(Example 2)
A surging detection method for the gas turbine compressor 1 according to the second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a sectional view showing the upper half of the flow path of the compressor 1 of the gas turbine that is Embodiment 1 of the present invention.

  The compressor shown in FIG. 3 is different from the compressor shown in FIG. 1 in that the temperature sensor 202 is arranged in the working flow channel upstream of the inlet guide vane 76 located at the inlet of the compressor 1. Thereby, the fluctuation information of the temperature of the atmospheric air 41 introduced into the compressor 1 can be obtained. This information can be used for predicting surging by monitoring the temperature upstream of the compressor last stage moving blade 74, and surging can be avoided more accurately. The flow rate of the water 61 sprayed by the intake spray cooling device 12 is also controlled by the atmospheric temperature. Therefore, the information from the temperature sensor 202 can also be used for controlling the amount of water 61 supplied to the intake spray cooling device 12.

(Example 3)
A surging detection method for a gas turbine compressor, which is Embodiment 3 of the present invention, will be described with reference to FIG. In FIG. 4, sectional drawing showing the upper half of the flow path of the compressor 1 of the gas turbine which is Example 3 of this invention is shown.

  The compressor shown in FIG. 4 differs from the compressor 1 shown in FIG. 1 in that it is downstream of the most upstream blades 75 on the downstream side of the evaporation completion position and upstream of the final blades 74. That is, at least one temperature sensor 203 is disposed in the working channel. As a result, in the unlikely event that choke occurs in the blade cascade upstream from the final stage, it is possible to quickly predict the occurrence of surging due to the stall of the blade cascade upstream of the compressor. Will improve.

  When the temperature sensor is measured on the upstream side of the evaporation completion position, droplets adhere to the temperature sensor during water spray, and accurate mainstream air temperature cannot be measured due to the heat conduction. Even when the gas turbine is stopped after water spraying and the gas turbine is restarted immediately, droplets may adhere to the temperature sensor, making it difficult to accurately measure the mainstream air temperature. Prediction accuracy of occurrence of surging decreases.

  Further, as a method of detecting a sign of turning stall or surging, there is a case where pressure or pressure fluctuation is measured by pressure sensors installed in a plurality of stages on the casing surface. When water is sprayed on the compressor, since there are droplets in the mainstream air, the droplets are sucked into the pressure tube that measures the pressure, and the inside of the tube may be blocked with droplets, which may reduce the measurement accuracy. . In addition, it is necessary to purge the pressure tube after the operation is completed and discharge the liquid droplets in the tube. For this purpose, an extra instrument serving as a purge air source is required.

  In addition, when the intake spray cooling device 12 is operated, the stage load of the compressor front stage blade row is reduced as shown in FIG. 2, and the stage load of the rear stage blade row that is downstream from the evaporation completion position is increased. . Further, since the flow rate of the water 61 sprayed by the intake spray cooling device 12 is controlled by the change in the atmospheric temperature introduced into the compressor 1, the evaporation completion position is not always constant. Like the compressor of the present embodiment, the temperature sensor 203 is arranged at a desired position at least at one position in the working flow path downstream of the evaporation completion position of the compressor and upstream of the moving blade 74 at the final stage. As a result, it becomes possible to monitor the cascade stall in more detail when the step load is excessively increased. As a result, it is possible to improve the accuracy of avoiding surging due to stall of the blade stage on the rear stage side.

Example 4
A control method for suppressing surging of a gas turbine compressor, which is Embodiment 4 of the present invention, will be described with reference to FIG. FIG. 5 is a sectional view showing the upper half of the flow path of the compressor 1 of the gas turbine that is Embodiment 4 of the present invention.

  The compressor 1 of the present embodiment can vary the blade angle by a hydraulic device 303 on the front stage side of the compressor 1 in order to prevent a rotating stall in the low rotation speed range at startup and to ensure a surge margin. It has a variable angle vane 101 such as an inlet guide vane (IGV). Further, the casing 73 of the compressor is provided with a bleed valve 302 for releasing bleed air from the bleed structure by the slit 91 and the bleed hole 92. The hydraulic device 303 and the extraction valve 302 are configured to be operable by a control signal from the control system 301.

  A control method for avoiding surging will be described. First, temperature information monitored by the temperature sensor 201 arranged upstream of the final stage moving blade 74 of the compressor 1 is transmitted to the control system 301. When the temperature received by the control system 301 is equal to or higher than the allowable choke temperature Tcr and it is determined that there is a risk of surging, a control signal is output from the control system 301.

  When this control signal is transmitted to the hydraulic device 303 of the variable angle stationary blade 101 located on the front stage side of the compressor 1, the variable angle stationary blade 101 is hydraulically controlled to reduce the suction flow rate of the compressor 1. . When it is determined that there is a risk of surging, the flow that flows into the moving blade row on the front side of the compressor 1 has a positive incidence, and the blade row suction surface side (the moving blade back side) It is estimated that peeling is occurring. At this time, if the variable angle stationary blade 101 is controlled to be closed, it is possible to suppress the separation on the suction surface side by adjusting the incidence of the inflow air to the moving blade row. Thus, by controlling to reduce the suction flow rate of the compressor 1, a surge margin can be ensured and surging can be avoided.

  On the other hand, when a control signal from the control system 301 is transmitted to the bleed valve 302, a part of the compressed working air can be released outside the system by opening the bleed valve 302. The extracted working air is discharged to the atmosphere through the exhaust duct of the turbine. In this way, by extracting a part of the compressor working fluid, choke of the rear stage blade row can be suppressed. Extraction of the working fluid leads to an increase in the suction flow rate that flows into the front stage of the compressor. Therefore, the axial flow speed to the front rotor blade row is increased, and separation of the suction surface side of the front rotor blade row is suppressed. be able to. Generation of surging can be avoided if separation on the suction surface side of the front rotor blade row can be suppressed.

(Example 5)
A control method for suppressing surging of a gas turbine compressor, which is Embodiment 5 of the present invention, will be described with reference to FIG. FIG. 6 is a sectional view showing the upper half of the flow path of the compressor 1 of the gas turbine that is Embodiment 5 of the present invention. The compressor 1 shown in FIG. 6 is structurally different from the compressor shown in FIG. 5 in that a slit 401 and a bleed hole 402 are provided in the casing on the upstream side of the moving blade 74 at the final stage of the compressor, and the bleed air is extracted from the bleed structure. This is that a bleed valve 403 for releasing the air is installed.

  The bleed valve 403 is configured as a device that can be operated by a control signal from the control system 301. First, the temperature is monitored by the temperature sensor 201 arranged on the upstream side of the final stage moving blade 74 of the compressor 1. When the control system 301 receives this temperature information and determines that the temperature is equal to or higher than the allowable choke temperature and the risk of surging is high, a control signal is output from the control system 301. The control signal is transmitted to the extraction valve 403, and the extraction valve 403 is opened to release a part of the compressed working air to the outside of the system.

  Usually, the bleeder mechanism of the compressor comprising the slit 91, the bleed hole 92, and the bleed valve 302 is provided for the following two purposes. When the compressor is operating in a low speed range, such as during startup, the working fluid is extracted in order to avoid choke of the rear stage blade row, turning stall of the front stage blade row, and surging. When operating in a high engine speed range, the working fluid is extracted for use as turbine blade cooling air. In the low speed range, the bleed valve is opened to extract about 15 to 20% of the operating flow rate of the compressor to avoid surging, and in the high speed range, the bleed valve is throttled to reduce the operating flow rate of about 2 ~ 3% is extracted and used as turbine blade cooling air.

  On the other hand, in the extraction mechanism including the slit 401, the extraction hole 402, and the extraction valve 403 provided in the compressor of this embodiment, the extraction valve 403 is opened only when choke is generated in the final stage of the compressor 1. Then, about 5 to 10% of the operating flow rate is extracted to avoid choking. The extracted compressed air is discharged from the turbine exhaust duct via the pipe. By using such a local bleed structure, it is possible to suppress choking of the rear blade row and avoid surging with a small amount of bleed flow.

  In consideration of the fact that the extraction stage of a normal compressor is used for cooling air of a turbine blade, it is set so that high-pressure air can be secured to the extent that it can cope with the differential pressure between the compressor side and the turbine side. . Therefore, in general, the bleed stage does not coincide with the stage choked by the blade row. In particular, an extraction stage is rarely provided near the final stage where choking is likely to occur for the following reason.

  Turbine blade cooling is introduced through a cooling passage in which the turbine first stage stationary blade is conducted from the compressor discharge casing to the stationary blade. In addition, cooling of the turbine blade is extracted from a slit on the rotor side downstream of the final stage blade of the compressor and introduced from the inner peripheral side of the turbine. Cooling air introduced from the outer peripheral side of the turbine by extraction from the casing of the compressor is performed via pipes on the first and subsequent stationary blades. In order to improve the gas turbine performance, it is important to introduce the cooling air having an optimum pressure to the extent that it can cope with the differential pressure between the compressor side and the turbine side. The pressure in the vicinity of the final stage of the compressor is a pressure that can ensure a sufficient differential pressure, but the differential pressure is too large and wasted, leading to a performance degradation of the gas turbine. In addition, since a combustor is arranged in the circumferential direction around the casing in the vicinity of the final stage of the compressor, a large bleed pipe that bleeds about 15 to 20% of the operating flow rate of the compressor in terms of structure. It is difficult to install.

  Since the extraction stage is in front of the stage in which the blade row chokes, an excessive extraction flow rate is discharged to avoid choking. This increase in the bleed flow rate is wasted because the compressed working fluid is exhausted by using the compression power, and the efficiency is lowered. If the choke stage and the extraction stage are made to coincide with each other as in the compressor of the present embodiment, the extraction flow rate for avoiding the choke can be suppressed and the efficiency reduction can be suppressed.

  Further, in the high-humidity utilization gas turbine as in the present embodiment, the entire discharge air amount of the compressor 1 is extracted and introduced into the humidifier 11. The humidifier 11 humidifies high-pressure air to increase the mass flow rate and lower the temperature. In such a gas turbine, a part of the humidified air 44 after passing through the humidifier 11 can be used for cooling the turbine blades. Blade cooling with humidified air has a higher heat transfer coefficient than air cooling and can improve cooling performance. This cooling method eliminates the need for piping for extracting blade cooling air from the compressor. That is, in the gas turbine provided with the humidifying device as in the present embodiment, it is not necessary to provide the blade cooling bleed means in the compressor. Instead of providing the bleed mechanism comprising the slit 91, the bleed hole 92, and the bleed valve 302, only the bleed mechanism comprising the slit 401, the bleed hole 402, and the bleed valve 403 may be provided. Extraction is possible.

  Hereinafter, a control method for avoiding surging of the compressor, including control of devices other than the compressor 1, will be described. When performing control including control of equipment other than the compressor 1, it is desirable to keep in mind that the rotational speed is kept constant. This is because in a gas turbine in which the compressor 1 and the turbine are coaxial, it is necessary to avoid shaft vibration and blade vibration due to excessive rotation, resonance of the compressor blade row due to low rotation speed maintenance, and the like.

  As shown in FIG. 7, the high humidity gas turbine according to the embodiment of the present invention receives a temperature sensor 201 disposed on the upstream side of the moving blade of the final stage of the compressor 1, and receives the temperature from the temperature sensor. The control system 301 that can be compared with the allowable choke temperature, the flow rate control valves 63 and 64 that can control the amount of water supplied to the intake spray cooling device 12 and the humidifier 11 by the output signal from the control system 301 and the discharge of the compressor 1 Is provided in a system for introducing the humid air 43 extracted from the humidifier 11, and is constituted by a discharge valve 65 that can control the operation flow rate and a fuel adjustment valve 32 that can adjust the flow rate of fuel supplied to the combustor 2. .

  The temperature information obtained by the temperature sensor 201 arranged on the upstream side of the final stage moving blade of the compressor 1 is sent to the control system 301. When it is determined that the temperature received by the control system 301 is equal to or higher than the allowable choke temperature and the risk of surging is high, a control signal is output from the control system 301.

  This output signal is transmitted to the air discharge valve 65 for releasing a part of the humid air 43 discharged from the compressor to the atmosphere. The discharge valve is fully opened according to the control signal, and the operating pressure ratio of the compressor can be lowered by releasing the compressed working air to the atmosphere. At this time, since the operating flow rate flowing into the turbine 3 is reduced, the fuel flow rate 31 is increased to keep the rotational speed constant. A plurality of air discharge valves 65 may be installed depending on the operating flow rate of the gas turbine, and the air can be discharged stepwise depending on the operating pressure ratio of the compressor.

  Further, the output signal is transmitted to the flow rate adjustment valve 64 that controls the amount of water in the humidifier 11. By reducing the amount of water supplied to the humidifier 11, the amount of moisture added to the working air can be reduced. Then, since the flow rate of the working air flowing into the turbine 3 is reduced, the fuel flow rate 31 is increased to keep the rotation speed constant. At this time, since the effect of decreasing the operating flow rate is greater than the effect of increasing the combustion temperature by increasing the fuel flow rate, the operating pressure ratio of the compressor 1 can be reduced, and surging can be avoided. it can.

  Further, the output signal is transmitted to the flow rate adjustment valve 63 that controls the amount of water in the intake spray cooling device 12, and the flow rate adjustment valve 63 is opened to spray droplets on the intake air. Thereby, the stage load of the compressor front stage cascade can be reduced, and the stage load of the rear stage cascade can be increased. Then, the choke of the rear stage blade row, the stall of the front stage blade row, and the surging caused thereby can be suppressed. At this time, since the operating flow rate flowing into the turbine 3 increases, the fuel flow rate 31 is decreased to keep the rotational speed constant.

  When the output signal is transmitted to the fuel adjustment valve 32 that adjusts the flow rate of the fuel supplied to the combustor 2, the operating pressure ratio of the compressor can be lowered by lowering the combustion gas temperature by reducing the fuel flow rate. it can. However, in this case, it is necessary to increase the amount of water 62 and 63 supplied to the humidifying device 11 or the intake spray cooling device 12 in order to keep the rotation speed constant. Regarding the rotational speed, the effect of increasing the operating flow rate is greater than the effect of increasing the combustion temperature due to the increase in the fuel flow rate, and the turbine may transiently over-rotate and the operating pressure ratio may also increase. Therefore, it is desirable that the fuel flow rate is not dynamically used for control, but for adjustment for maintaining a constant rotation speed.

  In the above control method, the discharge air of the compressor is most effective for reducing the pressure ratio. However, since high pressure air that consumes compression power is released to the atmosphere, the efficiency is reduced. Therefore, it is desirable to suppress the discharge amount as much as possible or to operate only in an emergency when the compressor causes surging. The supply of the water amount 61 to the intake spray cooling device 12 is excellent in that it can be realized by simple control. On the other hand, the control for supplying the amount of water 62 to the humidifier 11 can increase the combustion temperature by humidifying even at a partial load, and is effective in improving the efficiency at the partial load of the gas turbine.

  The multi-stage compressor of each embodiment measures at least the intermediate cooling mechanism that cools the working fluid being compressed, and the temperature of the fluid cooled by the intermediate cooling mechanism on the upstream side in the axial direction from the final stage moving blade. One temperature measurement means and a control means for controlling the surging suppression means based on the temperature measured by the temperature measurement means are provided. This configuration is a configuration that takes into account the stage load distribution of the compressor provided with the intermediate cooling device. In such a compressor, not only a surging sign of the rear stage blade row, which is downstream of the intermediate cooling mechanism, but also a choke sign can be detected. If the choke sign can be detected, it is possible to predict a stall occurring in the front stage blade cascade, and it is possible to effectively avoid the occurrence of surging due to this. In addition, since surging can be predicted by monitoring the minimum necessary temperature sensor, the complexity of the structure and control can be suppressed, which is effective in reducing costs and simplifying monitoring.

  The multistage compressor of each embodiment includes means for supplying water to the working fluid before being compressed or being compressed, and the water is configured to evaporate in the compressor. Suppression means, at least one temperature measuring means for measuring the temperature of the air between the water evaporation completion position and the final stage moving blade of the compressor, and surging suppression based on the temperature measured by the temperature measuring means Control means for controlling the means. In this configuration, the stage load of the compressor is reduced while water is evaporated in the compressor, and the stage load distribution is increased after evaporation due to the increase effect of the working fluid. In such a compressor, not only the surging sign of the rear stage blade row, which is downstream from the evaporation completion position, but also the choke sign can be detected. Then, surging can be effectively avoided as described above.

  The multi-stage compressor of each embodiment includes a determination unit that determines whether the temperature measured by the temperature measurement unit is equal to or higher than an allowable temperature. By this determination means, it is possible to perform optimal control appropriately utilizing temperature information obtained by the temperature measurement means.

  The temperature measuring means of the multistage compressor of each embodiment is provided between the last stage moving blade and the preceding stage stationary blade. In most cases, the last stage blade will first show signs of stall or choke leading to surging. Therefore, the surging of the compressor can be effectively controlled by monitoring at least the signs of the final stage moving blades.

  The multistage compressor of each embodiment includes any one of an inlet guide vane, a working fluid extraction means, a compressed working fluid discharge means, and a supply amount adjustment means of water supplied to the working fluid as surging suppression means. I have. By using such means, it is possible to actually take a surging avoidance action corresponding to the detected surging sign.

  The multi-stage compressor of each embodiment may be provided with a plurality of drain discharge holes in the axial direction, and a detecting means for detecting drain discharged from each drain discharge hole. In the droplet spraying to the compressor by the intake spraying device, the spray amount changes depending on the gas turbine output situation due to the change in the atmospheric temperature. Since the evaporation completion position of the droplet in the compressor also changes depending on the spray amount, the evaporation completion position can be specified by providing a drain amount detection means. By having such a configuration, the evaporation completion position can be detected from the presence or absence of drain. Further, by enabling the temperature measured by the temperature sensor attached to the stage without drain and invalidating the temperature measured by the temperature sensor attached to the stage with drain, better control becomes possible.

  The multi-stage compressor of each embodiment includes an intake spray device that sprays water onto air, a compressor that compresses moisture air generated by the intake spray device, and moisture air compressed by the compressor. A humidifier that humidifies, a combustor that mixes and burns humid air heated by the heat exchanger and fuel, a turbine that is driven to rotate by combustion gas generated by the combustor, and exhausted from the turbine In a gas turbine system comprising a heat exchanger that superheats the classified air supplied to the combustor by heat exchange with exhaust gas, the water sprayed by the intake spray device is configured to evaporate in the compressor And at least one temperature measuring means between the last stage moving blade of the compressor and the preceding stage stationary blade, and being compressed between the last stage moving blade of the compressor and the preceding stage stationary blade. Equipped with extraction means for extracting moisture air There. In such a high humidity cycle gas turbine system, surging can be effectively avoided as described above. In particular, since the amount of compressed air extracted for avoiding surging can be minimized, surging control can be performed without reducing system efficiency more than necessary.

  The multistage compressor of each embodiment may be provided with a cooling medium supply pipe that supplies moisture air humidified by a humidifier to the turbine cooled part. In such a high-humidity cycle gas turbine system, a system often used for cooling the blades by extracting the air being compressed by the compressor, which is often found in conventional gas turbines, is not required. The number can be reduced and the compressor structure can be simplified. Simplification of the structure leads to reduction in efficiency and cost. This is because it is possible to eliminate structures that obstruct the flow in the compressor and simplify the design.

Sectional drawing showing the upper half of the flow path of the compressor 1 of the gas turbine which is Example 1 of this invention is shown. The stage load distribution of the compressor 1 of the gas turbine which is an Example of this invention is shown. Sectional drawing showing the upper half of the flow path of the compressor 1 of the gas turbine which is Example 1 of this invention is shown. Sectional drawing showing the upper half of the flow path of the compressor 1 of the gas turbine which is Example 3 of this invention is shown. Sectional drawing showing the upper half of the flow path of the compressor 1 of the gas turbine which is Example 4 of this invention is shown. Sectional drawing showing the upper half of the flow path of the compressor 1 of the gas turbine which is Example 5 of this invention is shown. The system block diagram which shows the whole structure of the high-humidity utilization gas turbine system which is an Example of this invention is shown. The relationship between the operation schedule of the high humidity utilization gas turbine which is an Example of this invention, a rotation speed, and an output is shown. The characteristics of the flow coefficient and stage load coefficient of the last stage cascade and the upstream stage cascade of the compressor 1 of the high-humidity utilization gas turbine which is an embodiment of the present invention are shown. The inlet temperature of each stage of the compressor 1 of the high-humidity utilization gas turbine which is an Example of this invention is shown. Sectional drawing which looked at the AA cross section of FIG. 2 from the compressor upstream is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Compressor 2 Combustor 3 Turbine 4 Generator 6 Regenerative heat exchanger 11 Humidifying device 12 Intake spray cooling device 71, 72 Rotor blade, stationary blade 73 Casing 91, 92 Slit, extraction holes 201-203 Temperature sensor 301 Control system

Claims (9)

In a multi-stage compressor comprising means for supplying water to a working fluid before or during compression, wherein the water is configured to evaporate within the compressor,
Surging suppressing means for suppressing the occurrence of surging, at least one temperature measuring means for measuring the temperature of the air between the water evaporation completion position and the final stage moving blade of the compressor, and the temperature measuring means And a control means for controlling the surging suppression means using only the measured temperature. The compressor according to claim 1 ,
A compressor comprising: determination means for determining whether or not the temperature measured by the temperature measurement means is equal to or higher than an allowable temperature. The compressor according to claim 1 ,
The compressor characterized in that the temperature measuring means is provided between a last stage moving blade and a preceding stage stationary blade. The compressor according to claim 1 ,
The compressor is characterized in that the surging suppressing means is selected from an inlet guide vane, a working fluid extraction means, a compressed working fluid discharge means, and a supply amount adjusting means for water supplied to the working fluid. The compressor according to claim 1 ,
A compressor comprising: a plurality of drain discharge holes in an axial direction; and detecting means for detecting drain discharged from each drain discharge hole. Intake spray device for spraying water on air, compressor for compressing moisture air generated by the intake spray device, humidifier for humidifying the compressed air by the compressor, and the heat exchanger The combustor that mixes and burns the humid air heated by the fuel and the fuel, the turbine that is rotationally driven by the combustion gas generated by the combustor, and the exhaust gas exhausted from the turbine, exchanges heat with the combustor. In a gas turbine system including a heat exchanger that superheats supplied moisture air,
The water sprayed by the intake spray device is configured to evaporate in the compressor, and includes at least one temperature measuring means between a last stage moving blade of the compressor and a preceding stage stationary blade, and the compression A control means for controlling the extraction means by using only the temperature measured by the temperature measurement means, comprising extraction means for extracting moisture air in the middle of compression between the final stage moving blade of the machine and the preceding stationary blade gas turbine system comprising the means. The gas turbine system according to claim 6 .
A gas turbine system comprising a cooling medium supply pipe for supplying moisture air humidified by the humidifier to the turbine cooled part. In a control method for a multi-stage compressor, comprising an intermediate cooling mechanism for supplying water to be evaporated in the compressor to a working fluid before being compressed or being compressed, and a surging suppressing means.
The temperature of the fluid cooled by the intermediate cooling mechanism is measured downstream of the water evaporation completion position and axially upstream of the final stage blade, and the surging suppressing means is used only by using the measured temperature. A method for controlling a compressor, comprising controlling the compressor. Intake spray device for spraying water on air, compressor for compressing moisture air generated by the intake spray device, humidifier for humidifying the compressed air by the compressor, and the heat exchanger The combustor that mixes and burns the humid air heated by the fuel and the fuel, the turbine that is rotationally driven by the combustion gas generated by the combustor, and the exhaust gas exhausted from the turbine, exchanges heat with the combustor. Control of a gas turbine system comprising a heat exchanger that superheats supplied moisture air and surging suppression means for the compressor, and water sprayed by the intake spray device is configured to evaporate in the compressor In the method
After the humidification in the humidifier is stabilized, water spraying in the intake spray device is started, and moisture air is transferred between the evaporation completion position of the water sprayed in the intake spray device and the final stage blade of the compressor. A method for controlling a gas turbine system, comprising: measuring a temperature and controlling the surging control means using only the measured temperature.

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