High and low bypass heating system desuperheating water regulating valve advance control method and system

Abstract

The application discloses a high-low bypass heat supply system desuperheating water regulating valve advanced control method and system. The method comprises the following steps: obtaining a bypass heat supply system desuperheating water regulating valve advanced control curve through simulation test; and controlling the desuperheating water regulating valve opening degree according to the bypass valve opening degree, the set desuperheater rear temperature and the desuperheating water regulating valve advanced control curve. The controller controls the desuperheating water regulating valve opening degree according to the bypass valve opening degree, the set desuperheater rear temperature and the desuperheating water regulating valve advanced control curve, thereby avoiding the situation that the desuperheating water regulating valve response lags in adjustment of the bypass valve opening degree due to the desuperheater rear temperature change delay and the safety hidden danger caused by the desuperheater rear temperature fluctuation, and meanwhile, the accuracy of high bypass valve flow and low bypass valve flow calculation is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power generation, and particularly relates to a lead control method and system for a desuperheating water regulating valve of a high and low bypass heat supply system. BACKGROUND

[0002] According to the energy planning requirements of the State Energy Administration, the installed capacity of wind power, photovoltaic and other new energy power will continue to grow rapidly. In order to improve the power grid's ability to accommodate new energy, it is required to improve the peak shaving capacity of thermal power units, enhance the operational flexibility of thermal power units, and improve the new energy accommodation capacity. The flexibility modification of thermal power units that has been implemented enables the units to have the ability of deep peak shaving, and the main technologies include low-load stable combustion of the boiler, low-load denitration, zero output of the low-pressure cylinder, bypass heat supply, etc. Among them, the bypass heat supply has the advantages of low investment, flexible operation, high thermal-electric decoupling characteristics, etc., and has become one of the important technologies for thermal power unit thermal-electric decoupling modification, and has played a significant role in improving the heat supply capacity of power plants and realizing deep peak shaving.

[0003] However, the bypass heat supply changes the original proportion of steam entering the high and medium pressure cylinders, which deviates from the design value, which will directly affect the axial thrust of the unit. The overrun of the axial thrust will cause the unit thrust tile temperature, axial displacement, and high and medium pressure cylinder expansion difference to overrun, affecting the safe and stable operation of the unit. A typical high and low bypass heat supply system is shown in Figure 1 To solve this problem, the existing solution is to obtain the high bypass valve flow and the low bypass valve flow according to the mass balance and energy balance, and then control the high bypass valve opening degree according to the one-to-one relationship and the low bypass valve flow obtained by calculation. The control idea is to first adjust the low bypass valve opening degree to meet the heat supply demand, and then open the high bypass valve when the low bypass valve opening degree reaches the "threshold value" to maintain the balance of the high and medium pressure rotor axial thrust and ensure the safe operation of the unit.

[0004] A high (low) bypass system diagram is shown in Figure 2As shown, F1+F2=F3; F1·H1+F2·H2=F3·H3; H1=f(P1, T1); H2=f(P2, T2); H3=f(P3, T3), wherein F1, P1, T1 are the flow rate (t / h), pressure (MPa), and temperature (℃) of bypass steam before the desuperheater; F2, P2, T2 are the flow rate (t / h), pressure (MPa), and temperature (℃) of desuperheating water; F3, P3, T3 are the flow rate (t / h), pressure (MPa), and temperature (℃) of bypass steam after the desuperheater; H1 is the enthalpy of bypass steam before the desuperheater; H2 is the enthalpy of desuperheating water; and H3 is the enthalpy of bypass steam after the desuperheater. For the high bypass or low bypass: F2, P1, P2, P3, T1, T2, and T3 can be measured in real time, F1 and F3 can be obtained according to the above formula, and F1 between the high bypass and the low bypass can be matched according to the relationship between F1 of the high bypass and F1 of the low bypass (obtained according to a thermal balance diagram and high and medium pressure rotor axial thrust calculation), so that the high bypass F1 is adjusted by controlling the high bypass valve to match the low bypass F1, the high and medium pressure rotor axial thrust is within a safe range, and the safe and stable operation of the unit is ensured.

[0005] However, when the unit is actually running, the following problems may occur: when the opening degree of the high bypass valve (low bypass valve) is adjusted, the desuperheating water regulating valve will act accordingly to ensure that the temperature after the desuperheater is within a safe range, and the change of T3 will have a relatively obvious delay, because the measurement of the temperature after the desuperheater (temperature measuring element: thermocouple / thermal resistance) itself has a delay, and a certain time is needed for the mixing and uniformity after the desuperheater. Further, because the change of T3 will have a relatively obvious delay, the desuperheating water regulating valve will also have a lagging adjustment response, resulting in a lagging adjustment of the desuperheating water flow rate, and ultimately resulting in a long time and large amplitude fluctuation of T3, which will seriously affect the control of the steam temperature after the desuperheater, affect the safe operation of the unit, and affect the accuracy of the calculation of the high bypass valve flow rate and the low bypass valve flow rate. SUMMARY

[0006] The present application aims to at least partially solve one of the technical problems in the related art.

[0007] To this end, an embodiment of the present application provides a high and low bypass heating system desuperheating water regulating valve advance control method and system.

[0008] The present application provides a high and low bypass heating system desuperheating water regulating valve advance control method, comprising the following steps:

[0009] Simulating the bypass heating system desuperheating water regulating valve advance control curve;

[0010] The controller controls the opening degree of the desuperheating water regulating valve according to the opening degree of the bypass valve, the set temperature after the desuperheater, and the desuperheating water regulating valve advance control curve.

[0011] In some embodiments, the bypass heating system desuperheating water regulating valve advance control curve includes a high bypass heating system desuperheating water regulating valve advance control curve and a low bypass heating system desuperheating water regulating valve advance control curve.

[0012] In some embodiments, the controller controls the high bypass valve heating system desuperheating water regulating valve opening degree according to the high bypass heating system desuperheating water regulating valve advance control curve, and controls the low bypass valve heating system desuperheating water regulating valve opening degree according to the low bypass heating system desuperheating water regulating valve advance control curve.

[0013] In some embodiments, the controller includes a temperature setting module for setting the desuperheater rear temperature.

[0014] In some embodiments, the simulation test obtains a bypass heating system desuperheating water regulating valve advance control curve, including the following steps:

[0015] (1) selecting at least 5 temperature point values between the upper and lower limits of the desuperheater rear temperature design value, and selecting at least 5 valve opening point values within the maximum valve opening range of the bypass valve;

[0016] (2) inputting the high and low bypass heating systems, and making the high and low bypass heating systems run stably;

[0017] (3) adjusting the bypass valve opening degree to a certain valve opening point value, sequentially setting the desuperheater rear temperature to the selected temperature point value, adjusting the desuperheating water regulating valve opening degree until the high and low bypass heating systems run stably, and recording the desuperheating water regulating valve opening degree data under the combination of each valve opening point value and temperature point value;

[0018] (4) analyzing and processing the desuperheating water regulating valve opening degree data under each working condition to obtain the desuperheating water regulating valve advance control curve.

[0019] In some embodiments, the desuperheater rear temperature design value is determined according to the safe operation range of the unit.

[0020] In some embodiments, the bypass valve opening degree is a certain value, when the set desuperheater rear temperature is between two adjacent temperature point values, the desuperheating water regulating valve opening degree under the known conditions of bypass valve opening degree and set desuperheater rear temperature is determined according to the adjacent temperature point values and the corresponding desuperheating water regulating valve opening degree of the adjacent temperature point values on the desuperheating water regulating valve advance control curve.

[0021] In some embodiments, the high and low bypass heating systems run stably for 20-60 minutes.

[0022] The application provides a lead control system of a desuperheating water regulating valve of a high and low bypass heat supply system, which comprises the following:

[0023] A desuperheating water regulating valve is arranged for regulating the flow of desuperheating water.

[0024] A bypass valve is arranged upstream of the desuperheater for regulating the opening degree of the bypass.

[0025] A controller comprises a temperature setting module and a control module, and the temperature setting module, the desuperheating water regulating valve and the bypass valve are electrically connected to the control module.

[0026] In some embodiments, the bypass steam is cooled by the desuperheating water after passing through the desuperheater.

[0027] Compared with the prior art, the application has the following advantages:

[0028] The controller of the application controls the opening degree of the desuperheating water regulating valve according to the opening degree of the bypass valve, the set temperature after the desuperheater and the lead control curve of the desuperheating water regulating valve, thereby avoiding the situation that the desuperheating water regulating valve is adjusted in response to the delay of the temperature change after the desuperheater and the safety hazard caused by the temperature fluctuation after the desuperheater, and ensuring the accuracy of the calculation of the high bypass valve flow and the low bypass valve flow. BRIEF DESCRIPTION OF DRAWINGS

[0029] The above and / or additional aspects and advantages of the application will become apparent and be readily understood from the following description, including the accompanying drawings, in which:

[0030] Figure 1 It is a typical high and low bypass heat supply system diagram;

[0031] Figure 2 It is a high (low) bypass system diagram;

[0032] Figure 3 It is a schematic diagram of an exemplary lead control curve of a desuperheating water regulating valve of a low bypass heat supply system;

[0033] Figure 4 It is a schematic diagram of a lead control curve of a desuperheating water regulating valve of a low bypass heat supply system of an embodiment;

[0034] Figure 5 It is a schematic diagram of a lead control curve of a desuperheating water regulating valve of a high bypass heat supply system of an embodiment;

[0035] Figure 6 It is a schematic diagram of the control mode of the control system of the application. DETAILED DESCRIPTION

[0036] Embodiments of the present application are described below in detail with reference to the accompanying drawings, wherein the same or similar components or components having the same or similar functions are denoted by the same or similar reference numerals throughout. The embodiments described below by reference to the accompanying drawings are exemplary and are intended to explain the present application, and cannot be understood as limiting the present application.

[0037] A high-low bypass heating system desuperheating water regulating valve advance control method and system are described below with reference to the accompanying drawings according to embodiments of the present application.

[0038] The high-low bypass heating system desuperheating water regulating valve advance control method of the present application comprises the following steps:

[0039] A bypass heating system desuperheating water regulating valve advance control curve is obtained through simulation test;

[0040] The controller controls the desuperheating water regulating valve opening degree according to the bypass valve opening degree, the set desuperheater rear temperature and the desuperheating water regulating valve advance control curve.

[0041] The controller comprises a temperature setting module for setting the desuperheater rear temperature, and the bypass heating system desuperheating water regulating valve advance control curve comprises a high bypass heating system desuperheating water regulating valve advance control curve and a low bypass heating system desuperheating water regulating valve advance control curve. The controller controls the desuperheating water regulating valve opening degree of the high bypass heating system according to the high bypass heating system desuperheating water regulating valve advance control curve, and controls the desuperheating water regulating valve opening degree of the low bypass heating system according to the low bypass heating system desuperheating water regulating valve advance control curve.

[0042] The simulation test for obtaining the bypass heating system desuperheating water regulating valve advance control curve comprises the following steps:

[0043] (1) At least 5 temperature point values are selected between the upper and lower limits of the design value of the desuperheater rear temperature, and at least 5 valve opening point values are selected within the maximum valve opening range of the bypass valve;

[0044] (2) The high and low bypass heating systems are put into operation, and the high and low bypass heating systems are stably operated;

[0045] (3) The bypass valve opening degree is adjusted to a certain valve opening point value, the desuperheater rear temperature is sequentially set to the selected temperature point value, the desuperheating water regulating valve opening degree is adjusted until the high and low bypass heating systems are stably operated, and the desuperheating water regulating valve opening degree data under the combination of each valve opening point value and temperature point value are recorded;

[0046] (4) The desuperheating water regulating valve advance control curve is obtained by analyzing and processing the desuperheating water regulating valve opening degree data under each working condition.

[0047] The temperature design value after the desuperheater is determined according to the safe operation range of the unit, the maximum valve opening is determined according to the valve opening in the actual operation process of the unit, and in addition, it can be understood that the more temperature point values and valve opening point values are selected, the more reliable the test results are. The stable operation time of the high and low bypass heating system is 20-60 minutes.

[0048] In some embodiments, the bypass valve opening is adjusted to a certain valve opening point value, the temperature after the desuperheater is sequentially set to a selected temperature point value, the desuperheater water regulating valve opening is adjusted until the high and low bypass heating system is stably operated, and the desuperheater water regulating valve opening data under the combined working condition of each valve opening point value and temperature point value is recorded. Specifically, 5 temperature point values are sequentially selected between the upper and lower limits of the temperature design value after the desuperheater, and the temperature point values are T 3a , T 3b , T 3c , T 3d , and T 3e , wherein T 3a is the maximum value, and T 3e is the minimum value; according to the maximum valve opening in the actual operation process of the unit, 5 valve opening point values are selected within the range of the maximum valve opening, and the valve opening point values are K a , K b , K c , K d , and K e ; the high and low bypass heating system is put into operation, and is stably operated for 30 minutes; the bypass valve is adjusted to each valve opening point value, and the temperature after the desuperheater is sequentially set to a selected temperature point value, and then the desuperheater water regulating valve opening is adjusted until the system is stably operated for 30 minutes, and the final desuperheater water regulating valve opening (J) is recorded.

[0049] Exemplarily, the desuperheater water regulating valve opening data record table under the combined working condition of each valve opening point value and temperature point value is shown in Table 1.

[0050] Table 1: Desuperheater water regulating valve opening data record example table under the combined working condition of each valve opening point value and temperature point value.

[0051]

[0052] The desuperheater water regulating valve lead control curve of the bypass heating system is obtained by analyzing and processing the data recorded according to Table 1.

[0053] Exemplarily, the desuperheater water regulating valve lead control curve of the low bypass heating system is as shown in Figure 3As shown. The bypass valve opening is a fixed value. When the set temperature after the desuperheater is between two adjacent temperature points, the opening of the desuperheating water regulating valve is determined based on the adjacent temperature points and the corresponding opening of the desuperheating water regulating valve on the desuperheating water regulating valve's advance control curve, under the condition that the bypass valve opening and the set temperature after the desuperheater are known. For example, when the low-level bypass valve opening is D, the low-level bypass desuperheating water regulating valve's advance control parameter J can be automatically provided based on the low-level bypass heating system's desuperheating water regulating valve's advance control curve and the set temperature after the desuperheater valve. For example, if the set temperature T... 30 Located in two adjacent T3 (with T) 3a Corresponding to J a T 3b For example, corresponding to J b Between the test values, J0 can be determined using the following method:

[0054] Similarly, when the opening degree of the high-pressure bypass valve is G, the high-pressure bypass heating system desuperheating water regulating valve can be automatically given the high-pressure bypass desuperheating water regulating valve advanced control parameter J according to the advanced control curve of the high-pressure bypass heating system desuperheating water regulating valve and the set desuperheater valve downstream temperature.

[0055] In a specific embodiment, the upper and lower limits of the design temperature after the desuperheater in the low-temperature bypass heating system are 260℃ and 240℃, respectively. Five temperature points are selected between 260℃ and 240℃, namely 260℃, 255℃, 250℃, 245℃, and 240℃. The maximum opening value of the low-temperature bypass valve is 90%. Five low-temperature bypass valve opening points are selected within the 90% range, namely 10%, 30%, 50%, 70%, and 90%. The high-temperature and low-temperature bypass heating systems are put into operation and run stably for 30 minutes. The bypass valves are adjusted to the opening points of each valve, and the temperature setpoint after the desuperheater is set sequentially. Then, the opening of the desuperheating water regulating valve is adjusted until the system runs stably for 30 minutes. The final opening of the desuperheating water regulating valve is recorded, as shown in Table 2.

[0056] Table 2. Data record of desuperheating water regulating valve opening under various combinations of low valve opening point values ​​and temperature point values.

[0057]

[0058] Analyzing and processing the data in Table 2, the advanced control curve of the desuperheating water regulating valve in the low bypass heating system is obtained, as follows: Figure 4 As shown. Curves 1, 2, 3, 4, and 5 correspond to T respectively. 3a =260℃, T 3b =255℃, T 3c =250℃, T 3d =245℃, T 3e The anti-superheating water regulating valve's lead control curve at 240℃. For example, based on...Figure 4 According to the set desuperheater valve after temperature, the low bypass desuperheater water regulating valve is automatically given a leading control parameter J d If the set desuperheater valve after temperature is T d Between T 3a = 260℃ and T 3b = 255℃, then Accordingly, J d .

[0059] In some embodiments, the upper and lower limits of the design value of the desuperheater after temperature in the high bypass heating system are 290℃ and 270℃, and 5 temperature point values are selected between 290℃ and 270℃, which are 290℃, 285℃, 280℃, 275℃ and 270℃ respectively; the maximum value of the high bypass valve opening degree is 50%, and 5 high bypass valve opening degree point values are selected within the range of 50% of the high bypass valve opening degree, which are 5%, 10%, 15%, 30% and 50% respectively; the high and low bypass heating systems are put into operation, and stable operation is maintained for 30 minutes; the bypass valve is adjusted to each valve opening degree point value, and the desuperheater after temperature is set in turn, and then the desuperheater water regulating valve opening degree is adjusted until the system is stably operated for 30 minutes, and the final desuperheater water regulating valve opening degree is recorded, as shown in Table 3.

[0060] Table 3: Desuperheater water regulating valve opening degree data record table under the combination of each high valve opening degree point value and temperature point value working condition.

[0061]

[0062] By analyzing and processing the data in Table 3, the leading control curve of the desuperheater water regulating valve in the high bypass heating system is obtained, as shown in Figure 5 Curve 6, curve 7, curve 8, curve 9 and curve 10 respectively correspond to the desuperheater water regulating valve leading control curve when T 31 = 290℃, T 32 = 285℃, T 33 = 280℃, T 34 = 275℃ and T 35 = 270℃. For example, according to Figure 5 When the high bypass valve opening degree is 30%, the high bypass desuperheater water regulating valve is automatically given a leading control parameter J g If the set desuperheater valve after temperature is T g Between T 31 = 290℃ and T 32 = 285℃, then Accordingly, J g .

[0063] The high and low bypass heat supply system desuperheating water regulating valve advance control system comprises a desuperheating water regulating valve, a bypass valve, a desuperheater and a controller. The desuperheating water regulating valve is arranged on a desuperheating water flow pipeline and is used for regulating the desuperheating water flow; the bypass valve is arranged upstream of the desuperheater and is used for regulating the bypass opening; bypass steam is reduced in temperature after passing through the desuperheater under the action of the desuperheating water; the controller comprises a temperature setting module and a control module, and the temperature setting module, the desuperheating water regulating valve and the bypass valve are electrically connected with the control module. Figure 6 As shown in the figure, in the control process, the control module of the controller acquires the bypass valve opening and the temperature set by the temperature setting module after the desuperheater, controls the opening of the desuperheating water regulating valve according to the desuperheating water regulating valve advance control curve, avoids the safety hazard caused by the temperature fluctuation after the desuperheater, and guarantees the accuracy of the high bypass valve flow and the low bypass valve flow calculation.

[0064] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms can be directed to different embodiments or examples. Moreover, the described specific features, structures, materials or characteristics can be combined in any suitable manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples without contradiction.

[0065] In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise specifically limited.

[0066] Although the embodiments of the present application have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, replacements and variations can be made to these embodiments without departing from the principles and purposes of the present application, and the scope of the present application is defined by the claims and their equivalents.

Claims

1. A kind of high, low bypass heating system desuperheater valve advance control method, it is characterized in that, The method comprises the following steps: The simulation test obtains a lead control curve of a desuperheating water regulating valve of a bypass heating system; The controller controls the opening of the desuperheating water regulating valve according to the opening of the bypass valve, the set temperature after the desuperheater and the lead control curve of the desuperheating water regulating valve, The lead control curve of the desuperheating water regulating valve of the bypass heating system comprises a high bypass heating system desuperheating water regulating valve lead control curve and a low bypass heating system desuperheating water regulating valve lead control curve, The simulation test obtaining the lead control curve of the desuperheating water regulating valve of the bypass heating system comprises the following steps: (1) selecting at least 5 temperature point values between the upper and lower limits of the design value of the temperature after the desuperheater and at least 5 valve opening point values within the maximum valve opening range of the bypass valve; (2) inputting the high and low bypass heating systems to make the high and low bypass heating systems run stably; (3) adjusting the opening of the bypass valve to a certain valve opening point value, setting the temperature after the desuperheater to the selected temperature point value in turn, adjusting the opening of the desuperheating water regulating valve until the high and low bypass heating systems run stably, and recording the opening data of the desuperheating water regulating valve under the combined conditions of each valve opening point value and temperature point value; (4) analyzing and processing the opening data of the desuperheating water regulating valve under each condition to obtain the lead control curve of the desuperheating water regulating valve.

2. The method of claim 1, wherein, The controller controls the opening of the desuperheating water regulating valve of the high bypass heating system according to the high bypass heating system desuperheating water regulating valve lead control curve, and controls the opening of the desuperheating water regulating valve of the low bypass heating system according to the low bypass heating system desuperheating water regulating valve lead control curve.

3. The method of claim 1, wherein, The controller comprises a temperature setting module for setting the temperature after the desuperheater.

4. The method of claim 1, wherein, The design value of the temperature after the desuperheater is determined according to the safe operation range of the unit.

5. The method of claim 1, wherein, The opening of the desuperheating water regulating valve under the known conditions of the opening of the bypass valve and the set temperature after the desuperheater is determined according to the adjacent temperature point values and the corresponding openings of the desuperheating water regulating valve on the lead control curve of the desuperheating water regulating valve when the set temperature after the desuperheater is between two adjacent temperature point values.

6. The method of claim 1, wherein, The high and low bypass heating systems run stably for 20-60 minutes.

7. A lead control system for a desuperheating water regulating valve of a high and low bypass heating system, characterized in that, The method is used to implement the method according to any one of claims 1-6, comprising: a desuperheating water regulating valve for regulating the flow of desuperheating water; a bypass valve arranged upstream of the desuperheater for regulating the opening of the bypass; a controller comprising a temperature setting module and a control module, the temperature setting module, the desuperheating water regulating valve and the bypass valve being electrically connected to the control module.

8. The system of claim 7, wherein, The bypass steam is cooled by the desuperheating water after passing through the desuperheater.

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