A method for controlling the flow of cooling water in a gas turbine turbine cooler

Abstract

The embodiment of the application provides a flow control method for cooling water of a gas turbine turbine cooler, comprising: when the load of the gas turbine is less than 120 WM after starting, the condenser pneumatic door automatically adjusts the TCA cooler cooling water flow in a PID closed loop regulation mode, and the high-pressure header pneumatic door remains in a closed state; when the load of the gas turbine increases to more than 120 WM, the high-pressure header pneumatic door is gradually opened to the minimum opening degree at a preset rate, and after a preset delay, the TCA cooler cooling water flow is automatically adjusted in the PID closed loop regulation mode; when the high-pressure header pneumatic door is opened to the minimum opening degree, the condenser pneumatic door is gradually closed at a preset rate until fully closed; when an accident occurs and the actual cooling water flow value of the TCA cooler is lower than a preset flow threshold value, the high-pressure header pneumatic door is automatically removed and the current opening degree of the high-pressure header pneumatic door is maintained; meanwhile, the condenser pneumatic door is quickly opened to 60%, and after a preset delay, the condenser pneumatic door automatically adjusts the TCA cooler cooling water flow in the PID closed loop regulation mode.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of gas turbine technology, in particular to a flow control method for cooling water of a gas turbine turbine cooler. BACKGROUND

[0002] A gas turbine is an internal combustion engine in which a continuous flow of gas is used to drive a turbine, which in turn drives a compressor, and is a rotary engine in which the expansion of the gas occurs in a rotating blade assembly. The turbine cooling air system (TCA) of the gas turbine is used to cool the turbine rotor and moving blades, and the cooling air comes from the compressor exhaust and is supplied to the turbine rotor and moving blades after being cooled by the TCA. The cooling water of the TCA comes from the high-pressure feed water pump. Since the cooling effect of the TCA system directly affects the safe operation of the gas turbine turbine and the output of the gas turbine, it plays a very important role. In the prior art, the return high-pressure drum pneumatic door in the TCA cooler return high-pressure drum pipeline is open-loop controlled, the CV value of the valve is calculated according to the flow setting and the pressure difference before and after the TCA return high-pressure drum pneumatic door, and the opening of the valve is calculated according to the CV curve preset in the logic. Therefore, when the actual CV curve of the valve changes, there will be a large deviation between the valve opening calculated in this way and the set flow value, which cannot meet the TCA flow demand under the current operating condition of the gas turbine, and in serious cases, it may even threaten the safety of the unit. SUMMARY

[0003] The present application provides a flow control method for cooling water of a gas turbine turbine cooler to overcome at least one technical problem in the prior art.

[0004] According to an embodiment of the present application, a flow control method for cooling water of a gas turbine turbine cooler is provided, which is applied to a gas turbine turbine cooling system, and the gas turbine turbine cooling system comprises:

[0005] A high-pressure feed water pump group, the water inlet end of the high-pressure feed water pump group is connected with a high-pressure feed water main pipe;

[0006] A high-pressure economizer, a water outlet end of the high-pressure feed water pump group is connected with a water inlet end of the high-pressure economizer in communication, for supplying water to the high-pressure economizer;

[0007] An upper water regulating valve, the upper water regulating valve is arranged between the high-pressure economizer and the high-pressure feed water pump group, for regulating the upper water flow of the high-pressure economizer;

[0008] A first inlet flow meter, the first inlet flow meter is arranged between the upper water regulating valve and the high-pressure feed water pump group, for monitoring the actual water flow of the high-pressure economizer in real time;

[0009] a high-pressure steam drum, wherein the outlet end of the high-pressure economizer is connected to the inlet end of the high-pressure steam drum;

[0010] a TCA cooler, wherein the outlet end of the high-pressure feedwater pump group is connected to the inlet end of the TCA cooler to supply cooling water to the TCA cooler;

[0011] an inlet control valve, wherein the inlet control valve is arranged between the TCA cooler and the high-pressure feedwater pump group to control the water flow into the TCA cooler;

[0012] a second inlet flow meter, wherein the second inlet flow meter is arranged between the inlet control valve and the high-pressure feedwater pump group to monitor the actual cooling water flow of the TCA cooler in real time;

[0013] a high-pressure drum water delivery pipe, wherein the outlet end of the TCA cooler is connected to the high-pressure drum water delivery pipe, and the high-pressure drum water delivery pipe is connected to the inlet end of the high-pressure steam drum;

[0014] a high-pressure drum pneumatic valve, wherein the high-pressure drum pneumatic valve is arranged on the high-pressure drum water delivery pipe to control the water flow from the TCA cooler to the high-pressure steam drum;

[0015] a condenser water delivery pipe, wherein the outlet end of the TCA cooler is connected to the condenser water delivery pipe to deliver water from the TCA cooler to the condenser;

[0016] a condenser pneumatic valve, wherein the condenser pneumatic valve is arranged on the condenser water delivery pipe to control the water flow from the TCA cooler to the condenser;

[0017] a PID controller, wherein the input end of the PID controller is electrically connected to the second inlet flow meter, and the output end of the PID controller is electrically connected to the high-pressure drum pneumatic valve and the condenser pneumatic valve;

[0018] the flow control method comprises:

[0019] the second inlet flow meter monitors the actual cooling water flow of the TCA cooler in real time and sends the detected actual cooling water flow value to the PID controller;

[0020] when the load of the gas turbine is less than 120WM after starting, the condenser pneumatic valve automatically adjusts the cooling water flow of the TCA cooler by the PID controller in a PID closed-loop adjustment mode, and the high-pressure drum pneumatic valve is always kept in a closed state;

[0021] When the gas turbine load increases to 120WM or more, the high return air pneumatic door is gradually opened to the minimum opening degree at a preset first rate, and after a preset first delay time, the TCA cooler cooling water flow is automatically adjusted by the PID controller in a PID closed loop adjustment mode; when the high return air pneumatic door is opened to the minimum opening degree, the condenser pneumatic door is gradually closed at a preset second rate until it is fully closed.

[0022] When an accident occurs and the actual cooling water flow value of the TCA cooler is lower than the preset flow threshold value, the automatic control of the high return air pneumatic door is cut off, and the current opening degree of the high return air pneumatic door is maintained; at the same time, the condenser pneumatic door is quickly opened to 60%, and after a preset second delay time, the TCA cooler cooling water flow is automatically adjusted by the PID controller in a PID closed loop adjustment mode.

[0023] Preferably, the PID controller automatically adjusts the TCA cooler cooling water flow of the condenser pneumatic door in a PID closed loop adjustment mode, which specifically includes:

[0024] The PID controller receives the actual cooling water flow value of the TCA cooler detected by the second inlet flow meter, and compares the actual cooling water flow value with the set flow value of the condenser pneumatic door to obtain a first comparison result;

[0025] The PID controller calculates a first opening degree instruction of the condenser pneumatic door according to the first comparison result;

[0026] The PID controller communicates the first opening degree instruction to the controller of the condenser pneumatic door;

[0027] The controller of the condenser pneumatic door adjusts the opening degree of the condenser pneumatic door according to the first opening degree instruction to adjust the TCA cooler cooling water flow.

[0028] Preferably, the PID controller automatically adjusts the TCA cooler cooling water flow of the high return air pneumatic door in a PID closed loop adjustment mode, which specifically includes:

[0029] The PID controller receives the actual cooling water flow value of the TCA cooler detected by the second inlet flow meter, and compares the actual cooling water flow value with the set flow value of the high return air pneumatic door to obtain a second comparison result;

[0030] The PID controller calculates a second opening degree instruction of the high return air pneumatic door according to the second comparison result;

[0031] The PID controller communicates the second opening degree instruction to a controller of the high-pressure return air damper;

[0032] The controller of the high-pressure return air damper adjusts the opening degree of the high-pressure return air damper according to the second opening degree instruction to regulate the TCA cooler cooling water flow.

[0033] Further preferably, the preset flow threshold value is 70% of the set flow value of the high-pressure return air damper.

[0034] Still further preferably, the PID controller comprises a comparator.

[0035] The comparator compares the actual cooling water flow value with the set flow value of the condenser air damper and obtains a first comparison result.

[0036] The comparator compares the actual cooling water flow value with the set flow value of the high-pressure return air damper and obtains a second comparison result.

[0037] Preferably, the minimum opening degree of the high-pressure return air damper is 45%.

[0038] Preferably, the first rate is equal to the second rate; and the first delay time and the second delay time are both 5 seconds.

[0039] Preferably, the gas turbine turbine cooling system further comprises a first differential pressure transmitter, which is connected in parallel with the upper water regulating valve.

[0040] Preferably, the gas turbine turbine cooling system further comprises a second differential pressure transmitter, which is connected in parallel with the high-pressure return air damper.

[0041] Preferably, the high-pressure feed water pump group comprises a plurality of high-pressure feed water pumps, inlet manual valves, pressure reducing valves, outlet manual valves, outlet electric valves, check valves; the water inlet end of each high-pressure feed water pump is provided with an inlet manual valve and a pressure reducing valve; and the water outlet end of each high-pressure feed water pump is provided with a check valve, an outlet electric valve, and an outlet manual valve.

[0042] By applying the embodiments in this specification, the return high-pressure drum pneumatic valve corresponding to the TCA cooler is modified to PID closed-loop control. The valve opening is calculated by comparing the set flow rate with the actual flow rate, thereby achieving precise regulation of the TCA flow rate. This effectively solves the problem of large deviations between the calculated valve opening and the set flow rate value in the open-loop control process of the prior art. Simultaneously, by limiting the minimum opening of the return high-pressure drum pneumatic valve using this flow control method, over-adjustment of the PID controller can be prevented, avoiding frequent rapid opening of the return condenser pneumatic valve due to low TCA cooler flow. This improves the service life of the unit equipment and unit safety. The design further minimizes the occurrence of low TCA cooler flow during switching by gradually closing the return condenser pneumatic valve after the return high-pressure drum pneumatic valve reaches its minimum opening.

[0043] Furthermore, in an emergency, the automatic shut-off of the high-pressure drum pneumatic valve is maintained in its current position, while the condenser return pneumatic valve is quickly opened. Adjusting the TCA cooler cooling water flow through the condenser return pneumatic valve effectively avoids unnecessary mutual disturbance caused by simultaneous adjustment of two valves, resulting in more precise regulation. Simultaneously, directly introducing the TCA cooler return water into the high-pressure drum ensures that the high-pressure economizer feedwater pipeline and the TCA cooler feedwater pipeline are completely independent, preventing interference and facilitating easier control and enhancing practicality.

[0044] The innovative aspects of the embodiments in this specification include:

[0045] 1. In this embodiment, the cooling water flow control of the TCA cooler adopts PID closed-loop regulation throughout the entire process, so as to achieve precise regulation of the TCA cooler flow and effectively solve the problem of large deviation between the valve opening calculated in the open-loop control process and the set flow value in the prior art.

[0046] 2. In this embodiment, when the pneumatic valve for returning to the high-pressure steam drum corresponding to the TCA cooler is opened to the minimum opening, the pneumatic valve for returning to the condenser corresponding to the TCA cooler is gradually closed, which avoids the occurrence of low flow rate of the TCA cooler during the switching process to the greatest extent.

[0047] 3. In this embodiment, limiting the minimum opening of the return high-pressure steam turbine pneumatic valve can prevent the PID controller from over-adjusting, thereby avoiding the situation where the TCA cooler flow is low and triggers the return condenser pneumatic valve to open frequently and quickly, thus improving the service life of the unit equipment.

[0048] 4. In this embodiment, during an accident, the automatic return high-pressure steam drum pneumatic valve is cut off and kept in its current position, while the return condenser pneumatic valve is quickly opened. The cooling water flow rate of the TCA cooler is adjusted through the return condenser pneumatic valve, thus avoiding unnecessary mutual disturbance caused by the simultaneous adjustment of the two valves.

[0049] 5. In this embodiment, the return water from the TCA cooler is directly introduced into the high-pressure steam drum, so that the feed water pipeline of the high-pressure economizer and the feed water pipeline of the TCA cooler are completely opposite to each other and do not interfere with each other, making it easier to control. Attached Figure Description

[0050] To more clearly illustrate the technical solutions in the embodiments or prior art of this specification, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0051] Figure 1 This is a schematic diagram of the gas turbine cooling system to which the flow control method for cooling water in a gas turbine cooler provided in the embodiments of this specification is applied.

[0052] Figure 2 A structural block diagram of the gas turbine cooling system to which the flow control method for cooling water in a gas turbine cooler provided in the embodiments of this specification is applied;

[0053] Explanation of reference numerals in the attached diagram: 1 is the high-pressure feedwater pump, 2 is the inlet manual valve, 3 is the pressure reducing valve, 4 is the outlet manual valve, 5 is the outlet electric valve, 6 is the check valve, 7 is the high-pressure feedwater header, 8 is the high-pressure economizer, 9 is the water supply regulating valve, 10 is the first inlet flow meter, 11 is the high-pressure steam drum, 12 is the TCA cooler, 13 is the inlet control valve, 14 is the second inlet flow meter, 15 is the return water pipe to the high-pressure steam drum, 16 is the return pneumatic valve to the high-pressure steam drum, 17 is the return water pipe to the condenser, 18 is the return pneumatic valve to the condenser, 19 is the PID controller, 20 is the first differential pressure transmitter, 21 is the second differential pressure transmitter, 22 is the comparator, and 23 is the condenser. Detailed Implementation

[0054] The technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0055] It should be noted that the terms "comprising" and "having," and any variations thereof, in the embodiments and drawings of this specification are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or devices.

[0056] This specification discloses a method for controlling the flow rate of cooling water in a gas turbine cooler. The following sections provide detailed explanations.

[0057] The method for controlling the flow rate of cooling water in a gas turbine cooler is applied to a gas turbine cooling system. Figure 1 , Figure 2 This illustration shows a gas turbine cooling system to which a flow control method for cooling water in a gas turbine cooler, according to an embodiment of this description, is applied. For example... Figure 1 and Figure 2 As shown, the gas turbine cooling system includes a high-pressure feedwater pump set, a high-pressure economizer 8, a water supply regulating valve 9, a first inlet flow meter 10, a high-pressure steam drum 11, a TCA cooler 12, an inlet control valve 13, a second inlet flow meter 14, a return water pipe to the high-pressure drum 15, a return pneumatic valve to the high-pressure drum 16, a return water pipe to the condenser 17, a return pneumatic valve to the condenser 18, a first differential pressure transmitter 20, a second differential pressure transmitter 21, and a PID controller 19.

[0058] The gas turbine cooling system in this embodiment is supplied with cooling water by a high-pressure feedwater pump set. The inlet of the high-pressure feedwater pump set is connected to the high-pressure feedwater header 7, through which upstream water is transported to the high-pressure feedwater pump set. In a specific embodiment, the high-pressure feedwater pump set includes multiple high-pressure feedwater pumps 1, an inlet manual valve 2, a pressure reducing valve 3, an outlet manual valve 4, an outlet electric valve 5, and a check valve 6. Each high-pressure feedwater pump 1 has an inlet manual valve 2 and a pressure reducing valve 3 at its inlet, and each high-pressure feedwater pump 1 has a check valve 6, an outlet electric valve 5, and an outlet manual valve 4 at its outlet. The inlet manual valve 2 is used to manually control the connection or disconnection between the high-pressure feedwater pump 1 and the high-pressure feedwater header 7, and to manually control the water flow rate of the high-pressure feedwater pump 1. The pressure reducing valve 3 is used to reduce the pressure of the water flowing into the high-pressure feedwater pump 1 to meet the water pressure requirements of the high-pressure feedwater pump 1 and its downstream equipment. In addition, the check valve 6 is used to prevent water backflow and improve the safety of unit operation. The outlet electric valve 5 is used to automatically control the connection or disconnection between the high-pressure feed water pump 1 and the downstream equipment, and the outlet manual valve 4 is used to manually control the connection or disconnection between the high-pressure feed water pump 1 and the downstream equipment. The dual control of the output of the high-pressure feed water pump 1 makes it easier to achieve control, and the control is more reliable and safer.

[0059] Two paths are led out from the outlet of the high-pressure feedwater pump set. One path is connected to the inlet of the high-pressure economizer 8 to supply water to the high-pressure economizer 8. The other path is connected to the inlet of the TCA cooler 12 to supply cooling water to the TCA cooler 12.

[0060] Specifically, the high-pressure economizer 8 is connected to the outlet of the high-pressure feedwater pump set, which supplies water to the high-pressure economizer 8. To control the water supply to the high-pressure economizer 8, a water supply regulating valve 9 and a first inlet flow meter 10 are installed between the high-pressure economizer 8 and the high-pressure feedwater pump set. Specifically, the water supply regulating valve 9 is located between the high-pressure economizer 8 and the high-pressure feedwater pump set to regulate the water supply flow of the high-pressure economizer 8; the first inlet flow meter 10 is located between the water supply regulating valve 9 and the high-pressure feedwater pump set to monitor the actual water flow of the high-pressure economizer 8 in real time. Furthermore, a first differential pressure transmitter 20 is connected in parallel at the water supply regulating valve 9 to detect the differential pressure before and after the water supply regulating valve 9, and the water supply regulating valve 9 is preferably an electrically operated regulating valve. In one specific embodiment, the actual water flow rate of the high-pressure economizer 8 is detected by the first inlet flow meter 10 and sent to the PID controller 19. The differential pressure across the water inlet regulating valve 9 is detected by the first differential pressure transmitter 20 and sent to the PID controller 19. The PID controller 19 calculates the valve opening of the water inlet regulating valve 9 based on the actual water flow rate of the high-pressure economizer 8, the differential pressure across the water inlet regulating valve 9, and the set water flow rate of the high-pressure economizer 8, and sends the valve opening command to the control terminal of the water inlet regulating valve 9 to regulate the opening of the water inlet regulating valve 9, thereby controlling the water flow rate of the high-pressure economizer 8.

[0061] The TCA cooler 12 is also connected to the outlet of the high-pressure feedwater pump set, which supplies cooling water to the TCA cooler 12. To control the water flow rate of the TCA cooler 12, an inlet control valve 13 and a second inlet flow meter 14 are installed between the TCA cooler 12 and the high-pressure feedwater pump set. Specifically, the inlet control valve 13 is located between the TCA cooler 12 and the high-pressure feedwater pump set to control the water flow rate of the TCA cooler 12; the second inlet flow meter 14 is located between the inlet control valve 13 and the high-pressure feedwater pump set to monitor the actual cooling water flow rate of the TCA cooler 12 in real time. In another specific embodiment, the water flow rate of the TCA cooler 12 is automatically controlled by the inlet control valve 13, and the actual cooling water flow rate of the TCA cooler 12 is monitored in real time by the second inlet flow meter 14. The detected actual cooling water flow rate value of the TCA cooler 12 is sent to the PID controller 19 so that the PID controller 19 can control the cooling water flow rate of the TCA cooler 12.

[0062] In the embodiments described in this specification, two water outlets are drawn from the outlet of the TCA cooler 12: one is the high-pressure steam drum water return pipe 15 to the high-pressure steam drum 11, and the other is the condenser water return pipe 17 to the condenser 23.

[0063] Specifically, one end of the return water pipe 15 is connected to the outlet of the TCA cooler 12, and the other end is connected to the inlet of the high-pressure steam drum 11. The return water from the TCA cooler 12 is directly introduced into the high-pressure steam drum 11 through the return water pipe 15. Simultaneously, since the outlet of the high-pressure economizer 8 is also directly connected to the inlet of the high-pressure steam drum 11, in this embodiment, the high-pressure economizer 8 and the TCA cooler 12 are directly introduced into the high-pressure steam drum 11. The water supply lines between the high-pressure economizer 8 and the TCA cooler 12 are independent and do not interfere with each other, making control easier and adjustment simpler.

[0064] One end of the return water pipe 17 is connected to the outlet of the TCA cooler 12, and the other end is connected to the condenser 23. The return water from the TCA cooler 12 is then directly transported to the condenser 23 through the return water pipe 17.

[0065] In addition, to control the water flow rate from the TCA cooler 12 back to the high-pressure steam drum 11 and back to the condenser 23, a high-pressure steam drum pneumatic valve 16 is installed on the high-pressure steam drum water supply pipe 15. The high-pressure steam drum pneumatic valve 16 is used to regulate the water flow rate from the TCA cooler 12 to the high-pressure steam drum 11. Furthermore, a second differential pressure transmitter 21 is connected in parallel at the high-pressure steam drum pneumatic valve 16. The second differential pressure transmitter 21 is used to monitor the differential pressure before and after the high-pressure steam drum pneumatic valve 16 in real time. A condenser pneumatic valve 18 is installed on the condenser water supply pipe 17. The condenser pneumatic valve 18 is used to regulate the water flow rate from the TCA cooler 12 to the condenser 23.

[0066] In the gas turbine cooling system of this embodiment, the input terminal of the PID controller 19 is electrically connected to the second inlet flow meter 14, and the output terminal of the PID controller 19 is electrically connected to the return condenser pneumatic valve 16 and the return condenser pneumatic valve 18. In a specific embodiment, the PID controller 19 includes a comparator 22, which compares the actual cooling water flow rate with the set flow rate of the return condenser pneumatic valve and obtains a first comparison result; the comparator 22 also compares the actual cooling water flow rate with the set flow rate of the return condenser pneumatic valve and obtains a second comparison result. The PID controller 19 receives the actual cooling water flow rate of the TCA cooler 12 and compares it with the set flow rate of the return condenser pneumatic valve or the return high-pressure drum pneumatic valve by the comparator 22. The comparison result is calculated, and the PID controller 19 matches the corresponding valve opening of the return high-pressure drum pneumatic valve 16 or the return condenser pneumatic valve 18 according to the comparison result. The cooling water flow rate of the TCA cooler 12 is controlled by adjusting the valve opening of the return high-pressure drum pneumatic valve 16 or the return condenser pneumatic valve 18.

[0067] The flow control method for cooling water in a gas turbine cooler provided in the embodiments of this specification includes:

[0068] The second inlet flow meter monitors the actual cooling water flow of the TCA cooler in real time and sends the detected actual cooling water flow value to the PID controller.

[0069] The actual cooling water flow rate of the TCA cooler is detected in real time using a second inlet flow meter, and the detected actual cooling water flow rate value is sent to the PID controller. The PID controller then uses the actual cooling water flow rate value of the TCA cooler to perform closed-loop control of the return high-pressure steam drum pneumatic valve and the return condenser pneumatic valve, thereby adjusting the cooling water flow rate of the TCA cooler in real time and achieving precise adjustment of the cooling water flow rate of the TCA cooler.

[0070] In a specific implementation, the PID controller includes a comparator. The comparator compares the actual cooling water flow rate with the set flow rate of the condenser return pneumatic valve and obtains a first comparison result. The PID controller then performs further calculations based on this first comparison result, thereby regulating the cooling water flow rate of the TCA cooler by controlling the condenser return pneumatic valve. Similarly, the comparator compares the actual cooling water flow rate with the set flow rate of the high-pressure drum return pneumatic valve and obtains a second comparison result. The PID controller then performs further calculations based on this second comparison result, thereby regulating the cooling water flow rate of the TCA cooler by controlling the high-pressure drum return pneumatic valve.

[0071] When the gas turbine starts up and the load is less than 120MW, the pneumatic valve returning to the condenser automatically adjusts the cooling water flow of the TCA cooler through the PID controller using PID closed-loop regulation, and the pneumatic valve returning to the high-pressure drum remains closed.

[0072] Both the condenser return pneumatic valve and the effluent return pneumatic valve are PID closed-loop regulated based on the actual cooling water flow rate of the TCA cooler, and the switching between the condenser return pneumatic valve and the effluent return pneumatic valve is based on the gas turbine load. When the gas turbine starts and its load is less than 120 MW, the condenser return pneumatic valve automatically adjusts the cooling water flow rate of the TCA cooler, while the effluent return pneumatic valve remains closed until the gas turbine load reaches 120 MW. In a specific embodiment, the condenser return pneumatic valve automatically adjusts the TCA cooler cooling water flow rate using a PID controller with PID closed-loop regulation.

[0073] More specifically, the PID controller receives the actual cooling water flow rate of the TCA cooler detected by the second inlet flow meter, and compares the actual cooling water flow rate with the set flow rate of the return condenser pneumatic valve to obtain a first comparison result; the PID controller performs calculations based on the first comparison result to calculate the first opening command of the return condenser pneumatic valve; the PID controller communicates the first opening command to the controller of the return condenser pneumatic valve; the controller of the return condenser pneumatic valve adjusts the opening of the return condenser pneumatic valve according to the first opening command to regulate the cooling water flow rate of the TCA cooler.

[0074] In a specific implementation, the PID controller periodically samples the detection value of the second inlet flow meter and periodically calculates the actual cooling water flow rate of the TCA cooler. The sampling period can be set to 5 seconds, and the period for calculating the actual cooling water flow rate is an integer multiple of the sampling period. A comparator compares the actual cooling water flow rate with the set flow rate of the return condenser pneumatic valve to obtain a comparison result. In the embodiments of this specification, the comparison result can be proportional to the calculation result. The PID controller then calculates the calculation result based on the comparison result and outputs the corresponding first opening command of the return condenser pneumatic valve to the controller of the return condenser pneumatic valve. The controller of the return condenser pneumatic valve then adjusts the opening of the return condenser pneumatic valve according to the first opening command, thereby achieving the purpose of real-time automatic closed-loop regulation of the TCA cooler cooling water flow rate by the return condenser pneumatic valve.

[0075] When the gas turbine load increases to over 120 MW, the return-to-heater pneumatic valve gradually opens to its minimum opening at a preset first rate. After a preset first delay time, the return-to-heater pneumatic valve automatically adjusts the TCA cooler cooling water flow rate via a PID controller using a PID closed-loop regulation method. When the return-to-heater pneumatic valve reaches its minimum opening, the return-to-condenser pneumatic valve gradually closes at a preset second rate until it is fully closed. Furthermore, the minimum opening of the return-to-heater pneumatic valve is 45%, the first rate is equal to the second rate, and the first delay time is preferably 5 seconds.

[0076] When the gas turbine load increases to over 120 MW, the return-to-high-pressure drum pneumatic valve gradually opens to 45% at a preset first rate, meaning it opens to its minimum opening at a certain rate, and then engages automatic operation after 5 seconds. Simultaneously, after the return-to-high-pressure drum pneumatic valve opens to 45%, the return-to-condenser pneumatic valve gradually closes at a preset second rate until it is fully closed. Furthermore, as the gas turbine load increases, the return-to-condenser pneumatic valve remains in a standby closed state. In a specific embodiment, the return-to-high-pressure drum pneumatic valve automatically adjusts the TCA cooler cooling water flow rate using a PID controller with a PID closed-loop control method.

[0077] More specifically, the PID controller receives the actual cooling water flow rate of the TCA cooler detected by the second inlet flow meter, and compares the actual cooling water flow rate with the set flow rate of the return air valve to obtain a second comparison result; the PID controller performs calculations based on the second comparison result to calculate the second opening command of the return air valve; the PID controller communicates the second opening command to the controller of the return air valve; the controller of the return air valve adjusts the opening of the return air valve according to the second opening command to regulate the cooling water flow rate of the TCA cooler.

[0078] In a specific implementation, the PID controller periodically samples the detection value of the second inlet flow meter and periodically calculates the actual cooling water flow rate of the TCA cooler. The sampling period can be set to 5 seconds, and the period for calculating the actual cooling water flow rate is an integer multiple of the sampling period. A comparator compares the actual cooling water flow rate with the set flow rate of the return air intake pneumatic valve, thus obtaining a comparison result. In the embodiments of this specification, the comparison result can be proportional to the calculation result. The PID controller then calculates the calculation result based on the comparison result and outputs a corresponding second opening command for the return air intake pneumatic valve to its controller. The return air intake pneumatic valve controller then adjusts the opening of the return air intake pneumatic valve according to the second opening command, thereby achieving real-time automatic closed-loop regulation of the TCA cooler's cooling water flow rate.

[0079] The flow control method described in this specification limits the minimum opening of the return condenser pneumatic valve and sets it to gradually close the return condenser pneumatic valve after the return condenser pneumatic valve has opened to its minimum opening of 45%. On the one hand, this minimizes the occurrence of low TCA cooler flow during switching, improving unit safety; on the other hand, it prevents over-adjustment of the PID controller, thus avoiding frequent rapid opening of the return condenser pneumatic valve due to low TCA cooler flow, and extending the service life of the unit equipment.

[0080] When an accident occurs and the actual cooling water flow rate of the TCA cooler is lower than the preset flow threshold, the automatic control of the return high-pressure drum pneumatic valve is cut off, while maintaining the current opening of the return high-pressure drum pneumatic valve; simultaneously, the return condenser pneumatic valve is quickly opened to 60%, and after a preset second delay time, the return condenser pneumatic valve automatically adjusts the TCA cooler cooling water flow rate using a PID controller with closed-loop PID control. Furthermore, the preset flow threshold is 70% of the set flow rate value of the return high-pressure drum pneumatic valve, and the second delay time is preferably 5 seconds.

[0081] In a specific embodiment, during an accident, if the actual cooling water flow rate of the TCA cooler is lower than 70% of the set flow rate of the return high-pressure drum pneumatic valve, the automatic adjustment of the return high-pressure drum pneumatic valve can be cut off, and the current opening degree can be maintained. At the same time, the return condenser pneumatic valve is quickly opened to 60%, and after a 5-second delay, the return condenser pneumatic valve undergoes PID closed-loop adjustment, thereby automatically controlling the cooling water flow rate of the TCA cooler.

[0082] In the embodiments of this specification, during an accident, the automatic shut-off of the high-pressure steam drum pneumatic valve and the automatic activation of the condenser pneumatic valve are controlled. The cooling water flow of the TCA cooler is adjusted in a closed loop using the condenser pneumatic valve, which can bring the cooling water flow of the TCA cooler close to the set value as quickly as possible. It can also avoid unnecessary mutual disturbance caused by the simultaneous adjustment of the two valves, so as to achieve the best possible control effect.

[0083] The above describes the steps of the gas turbine cooler cooling water flow control method and the gas turbine cooling system provided in this embodiment. The complete process of the gas turbine cooler cooling water flow control method will be described in detail below.

[0084] In one specific embodiment, when the gas turbine starts up and the load is less than 120 MW, the condenser pneumatic valve automatically regulates the cooling water flow of the TCA cooler using a PID closed-loop control. Specifically, the second inlet flow meter measures the actual cooling water flow of the TCA cooler, compares it with the system-set flow rate value of the condenser pneumatic valve, calculates the difference, and then uses the PID controller to calculate the opening command of the condenser pneumatic valve. This opening command is communicated to the controller of the condenser pneumatic valve to realize the opening and closing action of the valve, so that it reaches the required opening state. The high-pressure drum pneumatic valve remains in a -5% closed state before the gas turbine load reaches 120 MW.

[0085] When the gas turbine load increases to over 120 MW, the return condenser pneumatic valve gradually opens to 45% at a rate of 30% per minute, and then automatically engages after 5 seconds for PID closed-loop regulation. Specifically, the second inlet flow meter measures the actual cooling water flow rate of the TCA cooler, compares it with the system-set flow rate value for the return condenser pneumatic valve, calculates the difference, and then uses the PID controller to calculate the opening command for the return condenser pneumatic valve. This command is communicated to the return condenser pneumatic valve controller to activate the valve, ensuring it reaches the required opening position. Simultaneously, when the return condenser pneumatic valve opens to 45%, it gradually closes at a rate of 10% per minute until it is fully closed to -2%. After this point, as the gas turbine load increases, the return condenser pneumatic valve remains in a standby closed state.

[0086] When an accident occurs, the TCA cooler flow rate will be low. When the actual value of the cooling water flow rate of the TCA cooler is lower than 70% of the set flow rate of the return high-pressure steam drum pneumatic valve, the automatic return high-pressure steam drum pneumatic valve will be cut off and the current valve opening will be maintained. At the same time, the return condenser pneumatic valve will be quickly opened to 60%. After a delay of 5 seconds, the cooling water flow rate of the TCA cooler will be automatically regulated by the PID closed loop of the return condenser pneumatic valve.

[0087] In this embodiment, when the gas turbine load exceeds 120 MW, the return condenser pneumatic valve is automatically adjusted by PID closed-loop control based on the TCA cooler cooling water flow rate. At the same time, the minimum opening degree of the return condenser pneumatic valve is limited to 45%, which prevents the problem of frequent rapid opening of the return condenser pneumatic valve due to low TCA flow when the PID automatic adjustment is not good.

[0088] In summary, this specification discloses a flow control method for cooling water in a gas turbine cooler. The method modifies the pneumatic valve of the return high-pressure drum corresponding to the TCA cooler into a PID closed-loop control. The valve opening is calculated by comparing the setpoint and actual flow rate, thus achieving precise regulation of the TCA flow rate. This effectively solves the problem of large deviations between the calculated valve opening and the set flow rate value in the open-loop control process of existing technologies. Furthermore, by limiting the minimum opening of the return high-pressure drum pneumatic valve using this flow control method, over-adjustment by the PID controller can be prevented, avoiding frequent rapid opening of the return condenser pneumatic valve due to low TCA cooler flow. This improves the service life and safety of the unit equipment. The design further minimizes the occurrence of low TCA cooler flow during switching by gradually closing the return condenser pneumatic valve after the return high-pressure drum pneumatic valve reaches its minimum opening.

[0089] Furthermore, in an emergency, the automatic shut-off of the high-pressure drum pneumatic valve is maintained in its current position, while the condenser return pneumatic valve is quickly opened. Adjusting the TCA cooler cooling water flow through the condenser return pneumatic valve effectively avoids unnecessary mutual disturbance caused by simultaneous adjustment of two valves, resulting in more precise regulation. Simultaneously, directly introducing the TCA cooler return water into the high-pressure drum ensures that the high-pressure economizer feedwater pipeline and the TCA cooler feedwater pipeline are completely independent, preventing interference and facilitating easier control and enhancing practicality.

[0090] Those skilled in the art will understand that the accompanying drawings are merely schematic diagrams of one embodiment, and the modules or processes shown in the drawings are not necessarily essential for implementing the present invention.

[0091] Those skilled in the art will understand that the modules in the apparatus of the embodiments can be distributed in the apparatus of the embodiments as described in the embodiments, or they can be located in one or more devices different from this embodiment with corresponding changes. The modules of the above embodiments can be combined into one module, or they can be further divided into multiple sub-modules.

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for controlling the flow rate of cooling water in a gas turbine cooler, characterized in that, The flow control method is applied to a gas turbine cooling system, which includes: A high-pressure water supply pump set, wherein the inlet end of the high-pressure water supply pump set is connected to the high-pressure water supply main pipe; The high-pressure economizer has a water outlet connected to the water inlet of the high-pressure economizer, which is used to supply water to the high-pressure economizer. A water supply regulating valve is installed between the high-pressure economizer and the high-pressure feed water pump group to regulate the water supply flow of the high-pressure economizer. The first inlet flow meter is installed between the water supply regulating valve and the high-pressure water supply pump group to monitor the actual water flow of the high-pressure economizer in real time. The high-pressure steam drum has its outlet end connected to the inlet end of the high-pressure economizer. The TCA cooler has another outlet connected to the inlet of the TCA cooler, which is used to supply cooling water to the TCA cooler. An inlet control valve is provided between the TCA cooler and the high-pressure feed water pump set to control the water inlet flow rate of the TCA cooler. The second inlet flow meter is installed between the inlet control valve and the high-pressure feed water pump group to monitor the actual cooling water flow of the TCA cooler in real time. A return water pipe is provided at the outlet of the TCA cooler; the return water pipe is connected to the inlet of the high-pressure steam drum. A high-pressure steam drum pneumatic valve is installed on the high-pressure steam drum water supply pipe and is used to regulate the water flow rate delivered from the TCA cooler to the high-pressure steam drum. A return condenser water supply pipe is provided, with another return condenser water supply pipe leading out from the outlet of the TCA cooler, used to transport the outlet water of the TCA cooler to the condenser; A pneumatic valve for returning to the condenser is installed on the water supply pipe of the returning condenser and is used to regulate the water flow rate delivered from the TCA cooler to the condenser. A PID controller, the input of which is electrically connected to the second inlet flow meter; the output of which is electrically connected to the return high-pressure steam drum pneumatic valve and the return condenser pneumatic valve. The flow control method includes: The second inlet flow meter monitors the actual cooling water flow of the TCA cooler in real time and sends the detected actual cooling water flow value to the PID controller; When the load of the gas turbine is less than 120MW after startup, the pneumatic valve of the condenser return valve automatically adjusts the cooling water flow of the TCA cooler through the PID controller using PID closed-loop regulation, and the pneumatic valve of the high-pressure drum return valve remains closed. When the gas turbine load increases to over 120 MW, the return-to-high-pressure drum pneumatic valve gradually opens to the minimum opening of 45% at a preset first rate. After a preset first delay of 5 seconds, the return-to-high-pressure drum pneumatic valve automatically adjusts the cooling water flow of the TCA cooler through the PID controller using PID closed-loop regulation. When the return-to-high-pressure drum pneumatic valve opens to the minimum opening, the return-to-condenser pneumatic valve gradually closes at a preset second rate until it is fully closed. When an accident occurs and the actual cooling water flow rate of the TCA cooler is lower than 70% of the set flow rate of the return high-pressure drum pneumatic valve, the automatic control of the return high-pressure drum pneumatic valve is cut off, and the current opening of the return high-pressure drum pneumatic valve is maintained; at the same time, the return condenser pneumatic valve is quickly opened to 60%, and after a preset second delay time of 5 seconds, the return condenser pneumatic valve automatically adjusts the cooling water flow rate of the TCA cooler through the PID controller using PID closed-loop regulation.

2. The method for controlling the flow rate of cooling water in a gas turbine cooler according to claim 1, characterized in that, The pneumatic valve of the condenser automatically adjusts the cooling water flow of the TCA cooler through the PID controller using a PID closed-loop regulation method, specifically including: The PID controller receives the actual cooling water flow rate of the TCA cooler detected by the second inlet flow meter, and compares the actual cooling water flow rate with the set flow rate of the return condenser pneumatic valve to obtain a first comparison result; The PID controller performs calculations based on the first comparison result to determine the first opening command of the pneumatic valve of the condenser. The PID controller communicates the first opening command to the controller of the pneumatic valve of the condenser. The controller of the condenser pneumatic valve adjusts the opening of the condenser pneumatic valve according to the first opening command, so as to regulate the cooling water flow rate of the TCA cooler.

3. The method for controlling the flow rate of cooling water in a gas turbine cooler according to claim 1, characterized in that, The high-pressure air valve automatically adjusts the cooling water flow of the TCA cooler through the PID controller using a PID closed-loop regulation method, specifically including: The PID controller receives the actual cooling water flow rate of the TCA cooler detected by the second inlet flow meter, and compares the actual cooling water flow rate with the set flow rate of the return high-pressure air valve to obtain a second comparison result; The PID controller performs calculations based on the second comparison result to determine the second opening command of the high-pressure pneumatic door. The PID controller communicates the second opening command to the controller of the return high-pressure pneumatic door; The controller of the return air intake pneumatic valve adjusts the opening of the return air intake pneumatic valve according to the second opening command, so as to regulate the cooling water flow rate of the TCA cooler.

4. The method for controlling the flow rate of cooling water in a gas turbine cooler according to claim 2 or 3, characterized in that, The PID controller includes a comparator; The comparator compares the actual cooling water flow rate with the set flow rate of the condenser pneumatic valve and obtains a first comparison result. The comparator compares the actual cooling water flow rate with the set flow rate of the return air intake pneumatic valve and obtains a second comparison result.

5. The method for controlling the flow rate of cooling water in a gas turbine cooler according to claim 1, characterized in that, The first rate is equal to the second rate.

6. The method for controlling the flow rate of cooling water in a gas turbine cooler according to claim 1, characterized in that, The gas turbine cooling system also includes a first differential pressure transmitter, which is connected in parallel with the water supply regulating valve.

7. The method for controlling the flow rate of cooling water in a gas turbine cooler according to claim 1, characterized in that, The gas turbine cooling system also includes a second differential pressure transmitter, which is connected in parallel with the return high pressure pneumatic valve.

8. The method for controlling the flow rate of cooling water in a gas turbine cooler according to claim 1, characterized in that, The high-pressure water supply pump group includes multiple high-pressure water supply pumps, an inlet manual valve, a pressure reducing valve, an outlet manual valve, an outlet electric valve, and a check valve; each of the high-pressure water supply pumps is equipped with an inlet manual valve and a pressure reducing valve at its inlet end; each of the high-pressure water supply pumps is equipped with a check valve, an outlet electric valve, and an outlet manual valve at its outlet end.

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