Flow regulating method and system based on circulating water quantity control value

Abstract

The application provides a flow regulation method and system based on a circulating water quantity control value, and the method comprises the following steps: continuously measuring the condensate water flow at the condensate water outlet of a steam turbine in a measurement period, wherein the measurement period comprises a plurality of time periods with the same length; performing integral average calculation on a plurality of condensate water flows measured in each time period in the measurement period to obtain an average value of the condensate water flow; and multiplying the average value of the condensate water flow by a preset circulating ratio to obtain the circulating water quantity control value. The application can reduce the difficulty and cost of measuring the circulating water quantity control value, and provides a simple method for circulating water flow control and flow regulation.

Description

Technical Field

[0001] This invention relates to the field of power generation equipment technology, and in particular to a flow regulation method and system based on circulating water volume control values. Background Technology

[0002] Currently, reducing back pressure can increase turbine output and improve steam heat utilization. When factors such as circulating cooling water temperature and condenser area cannot be changed due to constraints, the means to change back pressure is to adjust the circulation ratio. Increasing the circulation ratio by increasing the circulating water volume can reduce back pressure, but the power consumption for transporting circulating cooling water also increases accordingly. When the increased power consumption exceeds the increase in turbine power gained from reducing back pressure, the system benefit is negative; therefore, a higher circulation ratio is not always better. A suitable circulation ratio aims to maximize turbine thermal efficiency while minimizing the power consumption for transporting circulating cooling water, thereby minimizing overall energy consumption or maximizing turbine output.

[0003] Existing technical solutions typically optimize turbine back pressure, condenser area, and circulation ratio during the design phase, aiming to maximize turbine output after deducting circulating water pump power consumption. Once the design is finalized, the condenser area cannot be adjusted, and the circulating cooling water temperature is also affected by external factors. In actual operation, optimization can basically only be achieved by adjusting the circulation ratio and changing the turbine back pressure under different operating conditions to maximize overall efficiency.

[0004] The conventional approach is to use the condenser back pressure as the control target and feedback signal, and to use the difference between the actual back pressure and the target back pressure value as the adjustment signal for the circulating water pump.

[0005] Existing technologies that use condenser back pressure as a feedback signal have the following problems:

[0006] First, while back pressure is the most direct feedback signal, it is affected by many factors, making it difficult to directly determine whether the preset back pressure value is reasonable after deviating from the design conditions. For example, when the water temperature changes with the seasons, the actual limit back pressure and the optimal back pressure will deviate from the results calculated based on the rated water temperature. On-site, there is often only one set of design data calculated based on the rated water temperature, making it impossible to adjust the adjustment target in real time according to external factors.

[0007] Secondly, the actual pressure distribution from the exhaust port of the low-pressure cylinder of the steam turbine to the inside of the condenser exhibits a gradient, and the ratio of dynamic pressure to static pressure constantly changes. Changes in the turbine load also cause changes in the overall pressure gradient. Since the installation locations of the pressure measuring points are currently fixed, selecting representative pressure measuring points as control feedback signals is a challenge in actual operation.

[0008] Third, scale always exists on the water side of the condenser, and the impact of scale on the heat transfer coefficient cannot be measured and analyzed in real time. The optimal back pressure is affected by scale on the water side and cannot be measured or analyzed in real time. Therefore, the control target often deviates from the actual situation, and the theoretically optimal back pressure may not be applicable to the actual situation.

[0009] Therefore, the existing technology still needs further improvement and enhancement. Summary of the Invention

[0010] The purpose of this invention is to provide a flow regulation method and system based on circulating water volume control values, so as to reduce the measurement difficulty and cost of circulating water flow control.

[0011] To achieve the above objectives, in a first aspect, embodiments of the present invention provide a flow regulation method based on circulating water volume control values, the method comprising:

[0012] The condensate flow rate at the turbine condensate outlet is continuously measured within a measurement cycle, which includes multiple time periods of equal length.

[0013] The average condensate flow rate is obtained by integrating and averaging the multiple condensate flow rates measured at various time periods within the measurement cycle.

[0014] The average condensate flow rate is multiplied by the preset circulation ratio to obtain the circulating water volume control value.

[0015] Further, before obtaining the average condensate flow rate by integrating and averaging the multiple condensate flow rates measured at various time periods within the measurement cycle, the following steps are included:

[0016] The condensate flow rate measured during the first time period in the measurement cycle is assigned to the first register;

[0017] The condensate flow rate measured in the next time period of the measurement cycle is assigned to the next register, until the condensate flow rate measured in the last time period of the measurement cycle is assigned to the last register;

[0018] The measurement period corresponds to the number of registers.

[0019] Further, before assigning the condensate flow rate acquired during the first time period of the measurement cycle to the first register, the following steps are included:

[0020] When all registers contain 0 data, the condensate flow rate measured in the current time period is assigned to all registers.

[0021] Furthermore, after obtaining the circulating water volume control value, it includes:

[0022] The current condensate flow rate is detected in real time. When the difference between the current condensate flow rate and the circulating water volume control value exceeds a preset value, a flow control signal is sent to the circulating water pump according to the circulating water volume control value.

[0023] Furthermore, after obtaining the circulating water volume control value, it includes:

[0024] The presence of steam flow is detected in real time. If it is present, the steam flow value is obtained, and the steam flow value and the average value of the condensate flow are added together with a preset weight to obtain the steam correction circulating water control value.

[0025] A flow control signal is sent to the circulating water pump based on the steam-corrected circulating water volume control value.

[0026] Furthermore, after obtaining the circulating water volume control value, it includes:

[0027] When the generator output power signal is received, the generator output power signal is used as a load correction coefficient and multiplied by the circulating water volume control value to obtain the load correction circulating water volume control value.

[0028] The circulating water volume control value is adjusted according to the load, and a flow control signal is sent to the circulating water pump.

[0029] Secondly, embodiments of the present invention provide a flow regulation system based on circulating water volume control values, the system comprising: a flow transmitter, an integral averaging calculator, and a multiplier.

[0030] The flow transmitter is used to continuously measure the condensate flow rate at the turbine condensate outlet within a measurement cycle, and send the condensate flow rate to the integral average value calculator. The measurement cycle includes multiple time periods of equal length.

[0031] The integral average calculation unit is used to perform integral average calculation on multiple condensate flow rates measured in each time period within the measurement cycle to obtain the average condensate flow rate, and send the average condensate flow rate to the multiplier.

[0032] The multiplier is used to multiply the average condensate flow rate by a preset circulation ratio to obtain the circulating water volume control value.

[0033] Furthermore, the system also includes:

[0034] A flow controller is used to detect the current condensate flow rate in real time. When the difference between the current condensate flow rate and the circulating water volume control value exceeds a preset value, a flow control signal is sent to the circulating water pump according to the circulating water volume control value.

[0035] Furthermore, the flow controller is also used for:

[0036] The presence of steam flow is detected in real time. If it is present, the steam flow value is obtained, and the steam flow value and the average value of the condensate flow are added together with a preset weight to obtain the steam correction circulating water control value.

[0037] A flow control signal is sent to the circulating water pump based on the steam-corrected circulating water volume control value.

[0038] Furthermore, the flow controller is also used for:

[0039] When the generator output power signal is received, the generator output power signal is used as a load correction coefficient and multiplied by the circulating water volume control value to obtain the load correction circulating water volume control value.

[0040] The circulating water volume control value is adjusted according to the load, and a flow control signal is sent to the circulating water pump.

[0041] This invention provides a flow regulation method and system based on circulating water volume control values. The method involves continuously measuring the condensate flow rate at the turbine condensate outlet within a measurement cycle, where the measurement cycle includes multiple time periods of equal length. The average condensate flow rate is calculated by integrating and averaging the measured condensate flow rates from each time period within the measurement cycle. This average condensate flow rate is then multiplied by a preset circulation ratio to obtain the circulating water volume control value. This invention reduces the difficulty and cost of measuring circulating water volume control values, providing a simple method for circulating water flow control and regulation. Attached Figure Description

[0042] Figure 1 This is a schematic flowchart of a flow regulation method based on circulating water volume control value provided by an embodiment of the present invention;

[0043] Figure 2 This is a schematic diagram illustrating the calculation of the average condensate flow rate in a flow regulation method based on circulating water volume control value provided in an embodiment of the present invention.

[0044] Figure 3 This is a system block diagram of a flow regulation system based on circulating water volume control value provided in an embodiment of the present invention.

[0045] Figure 4 This is a schematic diagram of a flow regulation system based on circulating water volume control value provided in an embodiment of the present invention. Detailed Implementation

[0046] To make the objectives, technical solutions, and beneficial effects of this application clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Obviously, the embodiments described below are only part of the embodiments of the present invention and are used to illustrate the present invention, but are not intended to limit the scope of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0047] In one embodiment, such as Figure 1 As shown, a flow regulation method based on circulating water volume control value is provided, the method comprising:

[0048] S11. Continuously measure the condensate flow rate at the turbine condensate outlet within a measurement cycle, wherein the measurement cycle includes multiple time periods of equal length;

[0049] Here, condensate flow rate is used instead of condenser back pressure or exhaust steam flow rate as the input parameter for the control target; circulating water flow rate is used as the main feedback signal, making it convenient to acquire signals for the control system and ensuring accurate metering.

[0050] S12. Perform an integral average calculation on the multiple condensate flow rates measured in each time period within the measurement cycle to obtain the average condensate flow rate;

[0051] For example, a measurement cycle may consist of 5 time periods, and correspondingly, 5 registers may be set.

[0052] During initial startup, if all register data is "0", all registers are given the same initial value to ensure that the average value of the registers is the first flow value, thus avoiding the first flow value being incorrectly averaged.

[0053] The condensate flow rate measured during the first time period in the measurement cycle is assigned to the first register;

[0054] The condensate flow rate measured in the next time period of the measurement cycle is assigned to the next register, until the condensate flow rate measured in the last time period of the measurement cycle is assigned to the last register;

[0055] Specifically, such as Figure 2 As shown, during time period T1, each register is assigned an initial value Q1.

[0056] During time period T2, the newly acquired flow value Q2 overwrites the data in register R1.

[0057] During time period T3, the flow value Q3 overwrites the data in register R2.

[0058] The process continues until the last register is filled with new data. At this point, the data in register R1 is the oldest, so Q7 overwrites the data in R1, and this cycle continues.

[0059] This embodiment can be applied to multiple measurement cycles, with each cycle acquiring new data and overwriting the oldest values, and then performing an integral average calculation, i.e., the sum of all data divided by the number of registers. This process is continuously repeated to continuously output the average flow rate.

[0060] The number of time intervals in each measurement cycle should correspond to the number of registers. For example, if the measurement cycle is 30 seconds and data is acquired every second, then 30 registers are needed. If a more sensitive system response is desired, the measurement cycle can be shortened, such as setting the cycle to 15 seconds, which would require 15 registers; alternatively, the cycle can be set to 60 seconds and 60 registers can be configured to avoid oscillations caused by an overly sensitive system.

[0061] S13. Multiply the average condensate flow rate by the preset circulation ratio to obtain the circulating water volume control value.

[0062] Compared to using condenser back pressure as the control signal, this invention uses the product of the average condensate flow rate and the circulation ratio, which effectively simplifies the process of generating the circulating water control value and is easy to implement.

[0063] Using the design cycle ratio as a reference, correction coefficients for the cycle ratio under various loads can be pre-determined, and the cycle ratio can be determined according to specific conditions.

[0064] After obtaining the circulating water volume control value, the current condensate flow rate is detected in real time. When the difference between the current condensate flow rate and the circulating water volume control value exceeds a preset value, a flow control signal is sent to the circulating water pump according to the circulating water volume control value.

[0065] During unit operation, the average flow rate signal of condensate is continuously received, and the flow rate value is obtained through a transmitter and a square root calculator. The circulating water flow rate is multiplied by a preset circulation ratio by the circulating water flow calculator to obtain the target value of the circulating water flow rate, which is then used as the preset value. The transmitter and square root calculator acquire the circulating water flow rate in real time, and the measured value is compared with the target value through a difference calculator. When a difference exists, an operation signal is sent to the flow controller. At this point, the control achieves a first-level feedback loop closed loop. The above process can typically be implemented using PI, PID, or other controllers.

[0066] To improve response quality, a steam flow signal can be acquired as a feedforward signal and superimposed on the flow controller's command with a certain weight. Steam must pass through a steam turbine before being discharged to the condenser, and the condenser has a certain water storage space. Therefore, the input steam flow rate changes before the discharge steam rate or condensate flow rate. Thus, by increasing or decreasing the steam flow signal with a certain weight, a signal to increase or decrease the output of the circulating water pump can be sent, allowing the circulating water pump to adjust in advance. In specific implementation, this invention detects the presence of steam flow in real time. If present, the steam flow rate value is acquired, and the average value of the steam flow rate and the condensate flow rate are added with a preset weight to obtain the steam-corrected circulating water flow control value.

[0067] This invention can also introduce a power generation signal as a load correction coefficient, superimposed on the flow controller to further improve the accuracy of circulating water volume control. In a specific embodiment, when a generator output power signal is received, the generator output power signal is multiplied by the circulating water volume control value as a load correction coefficient to obtain the load-corrected circulating water volume control value.

[0068] The circulating water volume control value is adjusted according to the load, and a flow control signal is sent to the circulating water pump.

[0069] This invention provides a flow regulation method based on circulating water volume control value, which replaces the amount of steam discharged into the condenser with condensate flow rate, reducing measurement difficulty and cost, and providing a simple solution for circulating water flow control and flow regulation.

[0070] Based on the above-described flow regulation method based on circulating water volume control values, this invention also provides a flow regulation system based on circulating water volume control values, such as... Figure 3 As shown, it includes: a flow transmitter 1, an integral averaging unit 2, and a multiplier 3.

[0071] The flow transmitter 1 is used to continuously measure the condensate flow rate at the turbine condensate outlet within a measurement cycle, and send the condensate flow rate to the integral average calculation unit 2. The measurement cycle includes multiple time periods of equal length.

[0072] The integral average calculation unit 2 is used to perform integral average calculation on multiple condensate flow rates measured in each time period within the measurement cycle to obtain the average condensate flow rate, and send the average condensate flow rate to the multiplier 3.

[0073] The multiplier 3 is used to multiply the average condensate flow rate by a preset circulation ratio to obtain the circulating water volume control value.

[0074] The system also includes:

[0075] The flow controller 4 is used to detect the current condensate flow rate in real time. When the difference between the current condensate flow rate and the circulating water volume control value exceeds a preset value, a flow control signal is sent to the circulating water pump according to the circulating water volume control value.

[0076] The flow controller 4 is also used for:

[0077] The presence of steam flow is detected in real time. If it is present, the steam flow value is obtained, and the steam flow value and the average value of the condensate flow are added together with a preset weight to obtain the steam correction circulating water control value.

[0078] A flow control signal is sent to the circulating water pump based on the steam-corrected circulating water volume control value.

[0079] The flow controller 4 is also used for:

[0080] When the generator output power signal is received, the generator output power signal is used as a load correction coefficient and multiplied by the circulating water volume control value to obtain the load correction circulating water volume control value.

[0081] The circulating water volume control value is adjusted according to the load, and a flow control signal is sent to the circulating water pump.

[0082] like Figure 4 As shown, a specific example is provided. This system includes:

[0083] Condensate pump inlet pipe 101, condensate pump 102, condensate pump inlet pipe 103. The condensate pump system recovers the steam that cools and condenses into water.

[0084] The flow transmitter 201 and the square root calculator 202 are used to measure the condensate flow rate.

[0085] The integral averaging unit 300 is used to generate the average condensate flow rate over a period of time.

[0086] Multiplier 400 is used to calculate the average condensate flow rate and generate the target value for circulating water volume control.

[0087] The flow controller 500 is used to control the output of the circulating water pump to achieve the target value of the circulating water volume.

[0088] For specific limitations regarding a flow regulation system based on circulating water volume control values, please refer to the limitations of a flow regulation method based on circulating water volume control values ​​described above, which will not be repeated here. Each module in the above system can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device in hardware form, or stored in the memory of a computer device in software form, so that the processor can call and execute the operations corresponding to each module.

[0089] In summary, this invention provides a flow regulation method and system based on circulating water volume control values. The method includes: continuously measuring the condensate flow rate at the turbine condensate outlet within a measurement cycle, wherein the measurement cycle includes multiple time periods of equal length; performing an integral average calculation on the multiple condensate flow rates measured in each time period within the measurement cycle to obtain an average condensate flow rate; and multiplying the average condensate flow rate by a preset circulation ratio to obtain a circulating water volume control value. This invention reduces the difficulty and cost of measuring circulating water volume control values, providing a simple method for circulating water flow control and regulation.

[0090] The various embodiments in this specification are described in a progressive manner. For directly identical or similar parts of the embodiments, refer to each other. Each embodiment focuses on its differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. It should be noted that the technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification.

[0091] The embodiments described above are merely preferred embodiments of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various improvements and substitutions without departing from the technical principles of this invention, and these improvements and substitutions should also be considered within the scope of protection of this application. Therefore, the scope of protection of this patent application should be determined by the scope of the claims.

Claims

1. A flow regulating method based on a circulation water amount control value, characterized by, The method comprises: continuously measuring the condensate flow at the condensate outlet of the steam turbine during a measurement period, the measurement period comprising a plurality of time intervals of equal length; integrally averaging a plurality of the condensate flows measured during each time interval of the measurement period to obtain a condensate flow average value; multiplying the condensate flow average value by a preset circulation ratio to obtain a circulating water quantity control value real-time detecting a current condensate flow, and sending a flow control signal to the circulating water pump according to the circulating water quantity control value when a difference between the current condensate flow and the circulating water quantity control value exceeds a preset value.

2. The flow regulating method based on a circulation water amount control value according to claim 1, characterized by, Before integrally averaging a plurality of the condensate flows measured during each time interval of the measurement period to obtain a condensate flow average value, the method comprises: assigning the condensate flow measured during a first time interval of the measurement period to a first register; assigning the condensate flow measured during a next time interval of the measurement period to a next register, and so on until the condensate flow measured during a last time interval of the measurement period is assigned to a last register; the measurement period corresponds to the number of registers.

3. The flow regulating method based on a circulation water quantity control value according to claim 2, characterized in that, Before assigning the condensate flow obtained during a first time interval of the measurement period to a first register, the method comprises: when all the data in the registers are 0, assigning the condensate flow measured during a current time interval to all the registers.

4. The flow regulating method based on a circulation water quantity control value according to claim 1, characterized in that, After obtaining the circulating water quantity control value, the method comprises: real-time detecting whether there is steam flow, and if so, obtaining a steam flow value, adding the steam flow value and the condensate flow average value with a preset weight to obtain a steam-modified circulating water quantity control value; sending a flow control signal to the circulating water pump according to the steam-modified circulating water quantity control value.

5. The flow regulating method based on a circulation water quantity control value according to claim 1, characterized by, After obtaining the circulating water quantity control value, the method comprises: when a generator output power signal is received, multiplying the generator output power signal as a load correction coefficient with the circulating water quantity control value to obtain a load-modified circulating water quantity control value; sending a flow control signal to the circulating water pump according to the load-modified circulating water quantity control value.

6. A flow regulating system based on a circulating water quantity control value, characterized by, The system comprises a flow transmitter, an integral average value calculator and a multiplier: the flow transmitter is configured to continuously measure the condensate flow at the condensate outlet of the steam turbine during a measurement period, and send the condensate flow to the integral average value calculator, the measurement period comprising a plurality of time intervals of equal length; the integral average value calculator is configured to integrally average a plurality of the condensate flows measured during each time interval of the measurement period to obtain a condensate flow average value, and send the condensate flow average value to the multiplier; the multiplier is configured to multiply the condensate flow average value by a preset circulation ratio to obtain a circulating water quantity control value, and send a flow control signal to the circulating water pump according to the circulating water quantity control value when a difference between a current condensate flow and the circulating water quantity control value exceeds a preset value.

7. A flow regulating system based on a control value of a circulating water quantity according to claim 6, characterized in that, The system further comprises: The flow controller is used for detecting current condensate water flow in real time, and sending a flow control signal to the circulating water pump according to the circulating water quantity control value when a difference between the current condensate water flow and the circulating water quantity control value exceeds a preset value.

8. A flow regulating system based on a control value of a circulating water quantity according to claim 7, characterized in that, The flow controller is also used for: detecting whether there is steam flow in real time, obtaining a steam flow value if there is steam flow, and adding the steam flow value and the condensate water flow average value with a preset weight to obtain a steam corrected circulating water quantity control value; sending a flow control signal to the circulating water pump according to the steam corrected circulating water quantity control value.

9. A flow regulating system based on a control value of a circulating water quantity according to claim 7, characterized in that, The flow controller is also used for: multiplying the generator output power signal by the circulating water quantity control value as a load correction coefficient to obtain a load corrected circulating water quantity control value when the generator output power signal is received; sending a flow control signal to the circulating water pump according to the load corrected circulating water quantity control value.

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