Supercritical circulating fluidized bed unit dry and wet state automatic conversion and whole-course water supply control system and method
Through the automatic dry-wet state conversion and full-process water supply control system of supercritical circulating fluidized bed unit, the main steam flow is corrected using enthalpy value and bed temperature parameters, combined with power control, the problem of dry-wet state conversion of the unit during the deep peak shaving process is solved, and the unit's flexibility and new energy consumption capacity are improved.
Patent Information
- Application Number
- CN202510861456.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-25
- Publication Date
- 2025-09-02
AI Technical Summary
During the deep peak shaving process of supercritical circulating fluidized bed units, there are problems such as low automatic input rate, complex wet control strategies, large disturbances in dry and wet conversion, and breakpoints in load control, which affect the unit flexibility and new energy consumption capacity.
The supercritical circulating fluidized bed unit is adopted to automatically convert dry and wet state and full water supply control system. Through the combination of parameter transmitters and modules such as the final stage superheater and separator enthalpy deviation coefficient, main steam flow rate, average bed temperature and water-cooled wall temperature, dynamic correction and coordination control of water supply are achieved, combined with power control, to ensure the stability and continuity of the unit during the dry and wet state conversion process.
The continuous power control of the unit during the dry-wet-state conversion process is realized, the problems of bed temperature fluctuations and large wall temperature deviations are solved, and the unit's deep peak shaving capacity and new energy consumption capacity are improved.
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Figure CN120576369A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of automatic control technology, and in particular to a control system and method for automatic dry-wet state conversion and full-process water supply of a supercritical circulating fluidized bed unit. Background Art
[0002] Due to the high inertia, long delay, and wide fuel adaptability of supercritical circulating fluidized bed (CCFB) units, designing an automatic dry-wet state transition strategy is crucial for achieving deep peak shaving in these units. The proportion of renewable energy in the power system is rapidly increasing. However, renewable energy sources such as wind power and photovoltaics exhibit significant volatility and randomness. To address these characteristics and ensure reliable power supply, deep peak shaving capability has become a key performance characteristic of thermal power units. Supercritical CFB units, with their advantages of high efficiency and clean operation, occupy a vital position in the power supply system and shoulder the heavy responsibility of deep peak shaving. During deep peak shaving, SCB units experience significant load fluctuations, during which their operating state transitions between dry and wet states. Therefore, in-depth research on control systems for automatic dry-wet state transition in SCB units for deep peak shaving has far-reaching implications for improving the flexibility of thermal power units, enhancing the power system's ability to absorb renewable energy, and promoting the green and low-carbon energy transition. Summary of the Invention
[0003] In order to solve the problems of low automatic input rate, complex and difficult wet state control strategy, large disturbance of dry-wet state conversion, and load control breakpoints in the direct current boiler feed water control during the unit's deep peak regulation and coordinated load change process, this application proposes a supercritical circulating fluidized bed unit dry-wet state automatic conversion and full-process water supply control system and method.
[0004] The technical solution adopted in this application is: a supercritical circulating fluidized bed unit dry-wet state automatic conversion and full-process water supply control system, including: final superheater enthalpy deviation coefficient parameter transmitter PT1, main steam flow parameter transmitter PT2, separator enthalpy deviation coefficient parameter transmitter PT3, average bed temperature parameter transmitter PT4, different area water-cooled wall temperature maximum value parameter transmitter PT5, variable load and pressure deviation feedforward parameter transmitter PT6, feed water flow lower limit parameter transmitter PT7, final superheater enthalpy deviation coefficient parameter transmitter PT1 and main steam flow parameter transmitter PT2 are respectively used as inputs of multiplier module M1, the output of multiplier module M1 is connected in series with gain module M2, function generator module M3, inertia lag module M4, inertia lag module M5 and then input into multiplier module M11, separator enthalpy deviation coefficient parameter transmitter The transmitter PT3 serves as another input of the multiplier module M11. The output of the multiplier module M11 is connected to an input of the adder module M12. The other input of the adder module M12 is the output of the switch module M10. One input of the switch module M10 is the variable load and pressure deviation feedforward parameter transmitter PT6. The average bed temperature parameter transmitter PT4 is connected in series with the function generator M6 and then input into the multiplier module M8. The maximum value parameter transmitter PT5 of the water-cooled wall temperature in different areas is connected in series with the function generator M7 and then input into the multiplier module M8. The output of the multiplier module M8 is connected in series with the gain module M9 and then serves as another input of the switch module M10. The output of the adder module M12 and the water flow lower limit parameter transmitter PT7 serve as two inputs of the greater than comparison module M13 respectively. The output of the greater than comparison module M13 is the set water flow.
[0005] Furthermore, the final superheater enthalpy deviation coefficient = (actual enthalpy of the final superheater - actual enthalpy at the economizer inlet) / (preset enthalpy of the final superheater - preset enthalpy at the economizer inlet); Separator enthalpy deviation coefficient = (actual enthalpy at separator outlet - actual enthalpy at economizer inlet) / (preset enthalpy at separator outlet - preset enthalpy at economizer inlet).
[0006] Furthermore, the input of the final superheater enthalpy deviation coefficient parameter transmitter PT1 is connected to the first calculation module, which is used to calculate the enthalpy value based on the temperature and pressure data of the final superheater; The main steam flow rate is calculated by using the input turbine regulating stage pressure of the main steam flow parameter transmitter PT2; The input of the separator enthalpy deviation coefficient parameter transmitter PT3 is connected to the second calculation module, and the second calculation module calculates the enthalpy value according to the temperature and pressure data at the separator outlet; The input of the average bed temperature parameter transmitter PT4 is connected to the temperature sensor set at the bed temperature measuring point at the lower or middle part of the boiler furnace; The input of the parameter transmitter PT5 for taking the maximum value of the water-cooled wall temperature in different areas is connected to the temperature sensors installed on the water-cooled wall in the dense phase area, the water-cooled wall in the dilute phase area, the water-cooled wall in the burner area, the separator inlet and the water-cooled wall near the return feeder in the boiler furnace; The input of the variable load and pressure deviation feedforward parameter transmitter PT6 is connected to the unit collaborative control system.
[0007] Furthermore, the switch module M10 is a wet operation mode switching switch. When the switch module M10 is set to 0, the output of the switch module M10 is the variable load and pressure deviation feedforward parameter transmitter PT6, which is used to participate in the dry operation of the unit. When the switch module M10 is set to 1, the output of the switch module M10 is the average bed temperature parameter transmitter PT4 and the maximum value parameter transmitter PT5 of the water-cooled wall temperature in different areas, which are respectively multiplied and signal-conditioned by the function converters M4 and M5, and are used to participate in the wet operation of the unit.
[0008] Furthermore, the separator enthalpy deviation coefficient parameter transmitter PT3 is used to assist the main steam flow in regulating the feed water volume when the unit is switched between dry and wet states.
[0009] A method for automatic dry-wet state conversion and full-process water supply control of a supercritical circulating fluidized bed unit adopts the above-mentioned automatic dry-wet state conversion and full-process water supply control system of the supercritical circulating fluidized bed unit, comprising the following control steps: S1: Determine the lower limit of the feedwater flow rate during deep peak regulation operation of the unit, and obtain the actual enthalpy of the last superheater, the actual enthalpy of the economizer inlet, the actual enthalpy of the separator outlet, the main steam flow rate, the average bed temperature, the water-cooled wall temperature in different areas, the variable load, and the pressure deviation feedforward value; S2: Calculate (actual enthalpy of the final superheater - actual enthalpy at the economizer inlet) / (preset enthalpy of the final superheater - preset enthalpy at the economizer inlet) and (actual enthalpy at the separator outlet - actual enthalpy at the economizer inlet) / (preset enthalpy at the separator outlet - preset enthalpy at the economizer inlet) and input them into the multiplier module M1, and after adjustment by the gain module M2, the function generator module M3, the inertia lag module M4, and the M5, output O5, and input the output O5 together with the main steam flow into the multiplier module M11 to obtain the overall feed water setting O11; S3: When the unit is in dry operation mode, the variable load and pressure deviation feedforward values and the overall water supply O11 are simultaneously input into the adder module M12 to correct the overall water supply, and the corrected water supply O12 is output. The corrected water supply O12 is compared with the set water supply lower limit, and the larger value is taken as the final set water supply flow; S4: When the unit is in wet operation mode, the corrected water volume obtained based on the maximum value of the average bed temperature and the water-cooled wall temperature in different areas and the overall water supply volume O11 are simultaneously input into the adder module M12 to correct the overall water supply volume, and the corrected water supply volume O12 is output. The corrected water supply volume O12 is compared with the set water supply lower limit, and the larger value is taken as the final set water supply flow rate; During the load increase and load decrease process, the feed water volume is controlled according to the main steam flow rate, and the unit's dry-wet state and wet-dry state conversion control is realized.
[0010] Furthermore, during the load reduction process, the feed water volume is controlled according to the main steam flow rate to achieve the dry-wet state conversion control of the unit as follows: S5: When the unit is in dry operation mode, when the unit reduces the load, the feed water flow is reduced to maintain the minimum limit, and the combustion rate decreases as the load decreases. The feed water amount is controlled by the preset enthalpy value of the separator outlet under the wet working condition. When the preset enthalpy value of the separator outlet is low, the feed water amount is increased to realize the conversion from dry state to wet state, and the wet operation mode in step S4 is used to regulate the feed water amount. During the conversion process from dry state to wet state, the coordinated control system continues to automatically operate by controlling the power generation power through the turbine.
[0011] Furthermore, during the load increase process, the feed water volume is controlled according to the main steam flow rate to achieve the wet-dry state conversion control of the unit as follows: When the load is increased in the wet operation mode, the boiler increases the combustion rate output and controls the feed water volume through the preset enthalpy value at the separator outlet. When the preset enthalpy value at the separator outlet is too high, the feed water flow continues to maintain the minimum limit to achieve the conversion from wet to dry state, and the dry operation mode in step S3 is used to regulate the feed water volume. During the conversion process from wet to dry state, the coordinated control system continues to automatically operate by controlling the power generation power through the turbine.
[0012] A computer device comprises a memory, a processor and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of the method.
[0013] A computer-readable storage medium stores a computer program / instruction thereon, which implements the steps of the method when executed by a processor.
[0014] Compared with the existing technology, the present application has the following advantages: the present application utilizes the principle of dynamically correcting the main steam flow rate based on the enthalpy values of different dry and wet operating conditions, and simultaneously introduces real-time correction of the boiler bed temperature and the wall temperature of a certain area of the boiler. This method adopts the same control strategy for feedwater control in both dry and wet boiler modes, eliminating the need to switch or transform the feedwater control mode. At the same time, it combines power control with dry-wet state conversion control to achieve continuous power control during the dry-wet state conversion process, solving problems such as coordinated input, bed temperature fluctuations, and large wall temperature deviations during the dry-wet state conversion process, thereby improving the overall deep peak regulation capability of the unit. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The present application will be further described below with reference to the accompanying drawings: Figure 1 A schematic diagram of the system structure provided in an embodiment of the present application. DETAILED DESCRIPTION
[0016] like Figure 1 As shown, the present application provides a supercritical circulating fluidized bed unit dry-wet state automatic conversion and full-process water supply control system, including parameter transmitters (PT1-PT7), function generator modules (M3, M6, M7), multiplier modules (M1, M8, M11), switcher module M10, greater than comparison module M13, inertia lag module (M4, M5), adder module M12, and gain module (M2, M9).
[0017] The output end of the parameter transmitter PT1 is connected to the positive input end i1 of the multiplier module M1, and the output end of the main steam flow parameter transmitter PT2 is connected to the negative input end i2 of the multiplier module M1; the output end O1 of the multiplier module M1 is connected to the input end i2 of the gain module M2; the output end O2 of the gain module M2 is connected to the input end i4 of the function generator module M3. Then, the output terminal O3 of the function generator module M3 is connected to the input i5 of the inertia lag module M4, the output O4 of the inertia lag module M4 is connected to the input i6 of the inertia lag module M5, the output O5 of the inertia lag module M5 is connected to the input i7 of the multiplier module M11, and the output terminal of the (actual enthalpy value at the separator outlet - the actual enthalpy value at the economizer inlet) / (preset enthalpy value at the separator outlet - preset enthalpy value at the economizer inlet) parameter transmitter PT3 is connected to the input terminal i8 of the multiplier module M11.
[0018] The output end of the average bed temperature parameter transmitter PT4 is connected to the input end i9 of the function generator module M6, and the output end O6 of the function generator module M6 is connected to the input end i11 of the multiplier module M8; the output end of the parameter transmitter PT5 for taking the maximum value of the water-cooled wall temperature in different areas is connected to the input end i10 of the function generator module M7, the output end O7 of the function generator module M7 is connected to the input end i12 of the multiplier module M8, the output end O8 of the multiplier module M8 is connected to the input end i13 of the gain module M9, and the output end O9 of the gain module M9 is connected to the input end i14 of the switch module M10; the negative The output end of the load and pressure deviation feedforward parameter transmitter PT6 is connected to the input end i15 of the switch module M10, the output end O10 of the switch module M10 is connected to the input end i17 of the adder module M12, the output end O11 of the multiplier module M11 is connected to the input end i16 of the adder module M12, the output end O12 of the adder module M12 is connected to the input end i18 of the greater than comparison module M13, the output end of the water supply flow lower limit parameter transmitter PT7 is connected to the input end i19 of the greater than comparison module M13, and the output end O13 of the greater than comparison module M13 is connected to the water supply flow setting instruction.
[0019] (Actual enthalpy value of the final stage superheater - actual enthalpy value of the economizer inlet) / (preset enthalpy value of the final stage superheater - preset enthalpy value of the economizer inlet) and (actual enthalpy value of the separator outlet - actual enthalpy value of the economizer inlet) / (preset enthalpy value of the separator outlet - preset enthalpy value of the economizer inlet) are used to correct the main steam flow, overcoming the drawbacks of leading regulation caused by considering the actual enthalpy value of the separator outlet alone and lagging regulation caused by considering the actual enthalpy value of the final stage superheater alone. By comprehensively considering the actual enthalpy value of the separator outlet and the difference between the actual enthalpy value of the final stage superheater and the actual enthalpy value of the economizer inlet, and dividing it by the difference between the corresponding preset enthalpy values, two adjustment coefficients can be obtained as corrections to the main steam flow.
[0020] The average bed temperature is the average temperature of the bed material in the circulating fluidized bed (CFB) boiler furnace, and the water-cooled wall temperatures in different areas are the temperatures of the water-cooled walls in the dense phase zone (lower part of the furnace), the dilute phase zone (upper middle part of the furnace), the burner area, the separator inlet, and the water-cooled walls near the return feeder in the circulating fluidized bed (CFB) boiler furnace. The above two parameters are used as correction parameters for the unit during wet operation to further adjust the water feed rate at the output end O11 of the multiplier module M11.
[0021] The variable load and pressure deviation feedforward are used as correction parameters during dry operation of the unit and as feedforward adjustment quantities for the water supply at the output terminal O11 of the multiplier module M11.
[0022] Table 1 below is a table of the characteristics of the modules used in this application .
[0023] The function generator module M3 is a function generator module having the functional relationship shown in Table 2 below: .
[0024] The function generator module M6 is a function generator module having the functional relationship shown in Table 3 below: .
[0025] The function generator module M7 is a function generator module having the functional relationship shown in Table 4 below: .
[0026] When the switch module M10 determines that the dry and wet conditions change, the output value is equal to the Y / N condition input port of the switch module, and gradually changes to the input value at a change rate of 2.5t / h per second.
[0027] Due to the frequent fluctuations in the calorific value of the fuel in a circulating fluidized bed boiler, conventional coal-water ratio control strategies can easily cause large fluctuations in main steam temperature and pressure. A self-balancing feedwater control strategy, based on the enthalpy values of the final superheater and the separator outlet, modifies the main steam flow rate to dynamically reflect the heat released and absorbed by the boiler, ensuring a balance between the boiler's heat load and evaporation rate. The average furnace bed temperature and the boiler water-cooled wall temperature are directly integrated into the self-balancing feedwater control loop. When the unit is operating at low load, the water-to-fuel ratio entering the boiler exceeds the normal range, making the heat generated by fuel combustion insufficient to fully heat the added water, leading to a drop in bed temperature. This can also be accompanied by uneven heat load distribution. Excessive or insufficient feedwater can alter the heat absorption distribution across the heating surfaces, affecting the temperature uniformity within the furnace and causing large wall temperature deviations. Introducing a strongly coupled variable (average bed temperature and water-cooled wall temperature) better addresses the large bed temperature fluctuations and wall temperature deviations during the dry-wet transition process, thereby ensuring safe and stable operation of the unit during dry-wet transitions.
[0028] Based on the above system, the present application also proposes a method for automatic dry-wet state conversion and full-process water supply control of a supercritical circulating fluidized bed unit, comprising the following steps: S1: Determine the lower limit of the feedwater flow rate during deep peak regulation operation of the unit, and obtain the actual enthalpy of the last superheater, the actual enthalpy of the economizer inlet, the actual enthalpy of the separator outlet, the main steam flow rate, the average bed temperature, the water-cooled wall temperature in different areas, the variable load, and the pressure deviation feedforward value; S1: Determine the lower limit of the feedwater flow rate during deep peak regulation operation of the unit, and obtain the actual enthalpy of the last superheater, the actual enthalpy of the economizer inlet, the actual enthalpy of the separator outlet, the main steam flow rate, the average bed temperature, the water-cooled wall temperature in different areas, the variable load, and the pressure deviation feedforward value; S2: Calculate (actual enthalpy of the final superheater - actual enthalpy at the economizer inlet) / (preset enthalpy of the final superheater - preset enthalpy at the economizer inlet) and (actual enthalpy at the separator outlet - actual enthalpy at the economizer inlet) / (preset enthalpy at the separator outlet - preset enthalpy at the economizer inlet) and input them into the multiplier module M1, and after adjustment by the gain module M2, the function generator module M3, the inertia lag module M4, and the M5, output O5, and input the output O5 together with the main steam flow into the multiplier module M11 to obtain the overall feed water setting O11; S3: When the unit is in dry operation mode, the variable load and pressure deviation feedforward values and the overall water supply O11 are simultaneously input into the adder module M12 to correct the overall water supply, and the corrected water supply O12 is output. The corrected water supply O12 is compared with the set water supply lower limit, and the larger value is taken as the final set water supply flow; S4: When the unit is in wet operation mode, the corrected water cooling value obtained based on the maximum value of the average bed temperature and the water-cooled wall temperature in different areas and the overall water supply setting O11 are simultaneously input into the adder module M12 to correct the overall water supply, and the corrected water supply O12 is output. The corrected water supply O12 is compared with the set water supply lower limit, and the larger value is taken as the final set water supply flow rate; During the load increase and load decrease process, the water supply is controlled according to the main steam flow rate, and the unit is converted between dry and wet states and wet and dry states.
[0029] During the load reduction process, the feed water volume is controlled according to the main steam flow rate to achieve the dry-wet state conversion control of the unit as follows: S5: When the unit is in dry operation mode, when the unit reduces the load, the feed water flow is reduced to maintain the minimum limit, and the combustion rate decreases as the load decreases. The feed water amount is controlled by the preset enthalpy value of the separator outlet under the wet working condition. When the preset enthalpy value of the separator outlet is low, the feed water amount is increased to realize the conversion from dry state to wet state, and the wet operation mode in step S4 is used to regulate the feed water amount. During the conversion process from dry state to wet state, the coordinated control system continues to automatically operate by controlling the power generation power through the turbine.
[0030] During the load increase process, the feed water volume is controlled according to the main steam flow rate to achieve the wet-dry state conversion control of the unit as follows: When the load is increased in the wet operation mode, the boiler increases the combustion rate output and controls the feed water volume through the preset enthalpy value at the separator outlet. When the preset enthalpy value at the separator outlet is too high, the feed water flow continues to maintain the minimum limit to achieve the conversion from wet to dry state, and the dry operation mode in step S3 is used to regulate the feed water volume. During the conversion process from wet to dry state, the coordinated control system continues to automatically operate by controlling the power generation power through the turbine.
[0031] The water supply control method of the present application is significantly different from the water supply control method in the traditional dry-wet state control. The water supply in the traditional control method generally changes with the coal supply, and the water supply is regulated by the water-coal ratio. That is, when the load is reduced, the coal supply is reduced and the water supply is reduced synchronously. The method of the present application controls the water supply by the main steam flow rate. When the load is reduced, the water supply is regulated by judging whether the set value of the separator outlet temperature is too high. When the water supply increases, the dry-wet state conversion of the unit can be realized, and during the dry-wet state conversion process, the steam turbine adopts connected power control, realizing the combination of power control and dry-wet state conversion control, solving the problems of coordinated input, bed temperature fluctuation, large wall temperature deviation and so on in the dry-wet state conversion process, and improving the overall deep peak regulation capability of the unit.
[0032] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.
Claims
1. A supercritical circulating fluidized bed unit automatic dry-wet state conversion and full-process water supply control system, characterized by: include: The final superheater enthalpy deviation coefficient parameter transmitter PT1, the main steam flow parameter transmitter PT2, the separator enthalpy deviation coefficient parameter transmitter PT3, the average bed temperature parameter transmitter PT4, the maximum value parameter transmitter of the water-cooled wall temperature in different areas PT5, the variable load and pressure deviation feedforward parameter transmitter PT6, the feed water flow lower limit parameter transmitter PT7, the final superheater enthalpy deviation coefficient parameter transmitter PT1 and the main steam flow parameter transmitter PT2 are respectively used as the input of the multiplier module M1. The output of the multiplier module M1 is connected in series with the gain module M2, the function generator module M3, the inertia lag module M4, and the inertia lag module M5, and then input into the multiplier module M11. The separator enthalpy deviation coefficient parameter transmitter PT3 is used as another input of the multiplier module M11. The output of the multiplier module M11 is connected to one input of the adder module M12, the other input of the adder module M12 is the output of the switch module M10, and one input of the switch module M10 is the variable load and pressure deviation feedforward parameter transmitter PT6; the average bed temperature parameter transmitter PT4 is connected in series with the function generator M6 and then input into the multiplier module M8, the maximum value parameter transmitter PT5 of the water-cooled wall temperature in different areas is connected in series with the function generator M7 and then input into the multiplier module M8, the output of the multiplier module M8 is connected in series with the gain module M9 and then serves as another input of the switch module M10; the output of the adder module M12 and the water flow lower limit parameter transmitter PT7 are respectively used as the two inputs of the greater than comparison module M13, and the output of the greater than comparison module M13 is the set water flow.
2. The supercritical circulating fluidized bed unit dry-wet state automatic conversion and full-process water supply control system according to claim 1, characterized in that: Final superheater enthalpy deviation coefficient = (final superheater actual enthalpy - economizer inlet actual enthalpy) / (final superheater preset enthalpy - economizer inlet preset enthalpy); Separator enthalpy deviation coefficient = (actual enthalpy at separator outlet - actual enthalpy at economizer inlet) / (preset enthalpy at separator outlet - preset enthalpy at economizer inlet).
3. The supercritical circulating fluidized bed unit dry-wet state automatic conversion and full-process water supply control system according to claim 2, characterized in that: The input of the final superheater enthalpy deviation coefficient parameter transmitter PT1 is connected to the first calculation module, which is used to calculate the enthalpy value based on the temperature and pressure data of the final superheater; The input of the main steam flow parameter transmitter PT2 is connected to the turbine regulating stage pressure and calculates the main steam flow; The input of the separator enthalpy deviation coefficient parameter transmitter PT3 is connected to the second calculation module, and the second calculation module calculates the enthalpy value according to the temperature and pressure data at the separator outlet; The input of the average bed temperature parameter transmitter PT4 is connected to the temperature sensor set at the bed temperature measuring point at the lower or middle part of the boiler furnace; The input of the parameter transmitter PT5 for taking the maximum value of the water-cooled wall temperature in different areas is connected to the temperature sensors installed on the water-cooled wall in the dense phase area, the water-cooled wall in the dilute phase area, the water-cooled wall in the burner area, the separator inlet and the water-cooled wall near the return feeder in the boiler furnace; The input of the variable load and pressure deviation feedforward parameter transmitter PT6 is connected to the unit collaborative control system.
4. The supercritical circulating fluidized bed unit automatic dry-wet state conversion and full-process water supply control system according to claim 1 is characterized by: The switch module M10 is the wet operation mode switching switch. When the switch module M10 is set to 0, the output of the switch module M10 is the variable load and pressure deviation feedforward parameter transmitter PT6, which is used to participate in the dry operation of the unit. When the switch module M10 is set to 1, the output of the switch module M10 is the average bed temperature parameter transmitter PT4 and the maximum value parameter transmitter PT5 of the water-cooled wall temperature in different areas, which are respectively multiplied and signal-conditioned by the function converters M4 and M5, and are used to participate in the wet operation of the unit.
5. The supercritical circulating fluidized bed unit dry-wet state automatic conversion and full-process water supply control system according to claim 1 is characterized by: The separator enthalpy deviation coefficient parameter transmitter PT3 is used to assist the main steam flow in regulating the feed water volume during the dry-wet state conversion of the unit.
6. A method for automatic dry-wet state conversion and full-process water supply control of a supercritical circulating fluidized bed unit, characterized by: The supercritical circulating fluidized bed unit dry-wet state automatic conversion and full-process water supply control system according to any one of claims 1 to 5 includes the following control steps: S1: Determine the lower limit of the feedwater flow rate during deep peak regulation operation of the unit, and obtain the actual enthalpy of the last superheater, the actual enthalpy of the economizer inlet, the actual enthalpy of the separator outlet, the main steam flow rate, the average bed temperature, the water-cooled wall temperature in different areas, the variable load, and the pressure deviation feedforward value; S2: Calculate (actual enthalpy of the final superheater - actual enthalpy at the economizer inlet) / (preset enthalpy of the final superheater - preset enthalpy at the economizer inlet) and (actual enthalpy at the separator outlet - actual enthalpy at the economizer inlet) / (preset enthalpy at the separator outlet - preset enthalpy at the economizer inlet) and input them into the multiplier module M1, and after adjustment by the gain module M2, the function generator module M3, the inertia lag module M4, and the M5, output O5, and input the output O5 together with the main steam flow into the multiplier module M11 to obtain the overall feed water setting O11; S3: When the unit is in dry operation mode, the variable load and pressure deviation feedforward values and the overall water supply O11 are simultaneously input into the adder module M12 to correct the overall water supply, and the corrected water supply O12 is output. The corrected water supply O12 is compared with the set water supply lower limit, and the larger value is taken as the final set water supply flow; S4: When the unit is in wet operation mode, the corrected water volume obtained based on the maximum value of the average bed temperature and the water-cooled wall temperature in different areas and the overall feed water flow setting O11 are simultaneously input into the adder module M12 to correct the overall feed water volume, and the corrected feed water volume O12 is output. The corrected feed water volume O12 is compared with the set lower limit of the feed water volume, and the larger value is taken as the final set feed water flow; During the load increase and load decrease process, the feed water volume is controlled according to the main steam flow rate, and the unit's dry-wet state and wet-dry state conversion control is realized.
7. The method for automatic dry-wet state conversion and full-process water supply control of a supercritical circulating fluidized bed unit according to claim 6, characterized in that: During the load reduction process, the feed water volume is controlled according to the main steam flow rate to achieve the dry-wet state conversion control of the unit as follows: S5: When the unit is in dry operation mode, when the unit reduces the load, the feed water flow is reduced to maintain the minimum limit, and the combustion rate decreases as the load decreases. The feed water amount is controlled by the preset enthalpy value of the separator outlet under the wet working condition. When the preset enthalpy value of the separator outlet is low, the feed water amount is increased to realize the conversion from dry state to wet state, and the wet operation mode in step S4 is used to regulate the feed water amount. During the conversion process from dry state to wet state, the coordinated control system continues to automatically operate by controlling the power generation power through the turbine.
8. The method for automatic dry-wet state conversion and full-process water supply control of a supercritical circulating fluidized bed unit according to claim 6, characterized in that: During the load increase process, the feed water volume is controlled according to the main steam flow rate to achieve the wet-dry state conversion control of the unit as follows: When the load is increased in the wet operation mode, the boiler increases the combustion rate output and controls the feed water volume through the preset enthalpy value at the separator outlet. When the preset enthalpy value at the separator outlet is too high, the feed water flow continues to maintain the minimum limit to achieve the conversion from wet to dry state, and the dry operation mode in step S3 is used to regulate the feed water volume. During the conversion process from wet to dry state, the coordinated control system continues to automatically operate by controlling the power generation power through the turbine.
9. A computer device comprising a memory, a processor, and a computer program stored in the memory, wherein: The processor executes the computer program to implement the steps of the method according to any one of claims 5 to 7.
10. A computer-readable storage medium having a computer program / instruction stored thereon, characterized in that: When the computer program / instruction is executed by a processor, the steps of the method according to any one of claims 5 to 7 are implemented.