A control method of a deep-tuned fire power coupling molten salt system, an electronic device and a storage medium

Abstract

The application discloses a control method of a deep-tuned fire power coupling molten salt system, an electronic device and a storage medium, and the fire power coupling molten salt is divided into two working conditions of small deviation and large deviation by judging the difference between a unit power set value and an actual unit power, energy storage and energy release modes are determined according to start conditions and the difference, power is distributed to a molten salt controller and a unit coordination controller through a power distributor, and steam extraction and water extraction are used as control quantities respectively, so that fire storage combined control is realized. Through the power distributor and the distribution of the working conditions, the unit power and the main steam pressure are better tracked and controlled, the overshoot of the unit power under the molten salt control is obviously reduced, and the difference-free tracking of the load instruction can be quickly realized. Since the molten salt control has a small influence on the operation of the unit boiler, the main steam pressure of the unit fluctuates little, and therefore the pressure control is more stable, and the steam extraction amount changes more rapidly and stably.

Description

Technical Field

[0001] This invention relates to a control method, electronic equipment, and storage medium for a thermal power coupled molten salt system under deep regulation, belonging to the technical field of thermal power and energy storage joint regulation control methods. Background Technology

[0002] By the end of 2023, the installed capacity of renewable energy power generation in China exceeded 1.4 billion kilowatts, accounting for nearly half of the total installed capacity. Against this backdrop, the power system faces new challenges: the inherent intermittency and volatility of new energy power generation lead to a decline in grid frequency regulation capabilities, insufficient rotational inertia, and a surge in peak-shaving demand. It has become an industry consensus that traditional coal-fired power units must transform from "baseload power sources" to "regulatory power sources" and "support power sources." The core characteristics of the new generation of coal-fired power are reflected in three aspects: deep flexibility, rapid response, and low-carbon efficiency. Traditional coal-fired units, limited by boiler thermal inertia and turbine thermal stress, typically only achieve a peak-shaving depth of 50% of rated load, with a ramp rate of only 1% of rated power per minute. This is insufficient to meet the future grid's requirements for "minute-level response and hour-level continuity" of regulation resources.

[0003] Therefore, achieving deep and flexible retrofitting of coal-fired power units through technological innovation has become a key measure to ensure the safe and stable operation of the power system and promote the consumption of new energy sources. High-temperature molten salt energy storage technology provides a solution for deep and flexible retrofitting. Molten salt energy storage media based on the nitrate system has advantages such as a wide operating temperature range (290-565℃), large heat capacity, and relatively low cost, and is highly compatible with the thermal parameters of coal-fired power units. When the energy storage system is coupled with the coal-fired power unit, multiple functions can be optimized: during periods of low grid load, the unit extracts steam to heat the molten salt to store thermal energy, achieving a rapid decrease in output, which can be reduced to below 30% of the rated load; during periods of high load, the stored thermal energy generates high-temperature steam through a heat exchange system to supplement power generation, rapidly increasing the unit's output. This "peak shaving and valley filling" capability not only improves the unit's regulation range but also improves the unit's operating economy—allowing the main unit to operate in the high-efficiency range for more time, while the load regulation task is handled by the faster-responding energy storage system.

[0004] However, deeply coupling two systems with vastly different physical characteristics presents unprecedented control challenges. The response time constant of a molten salt energy storage system is on the order of minutes, while that of a coal-fired boiler ranges from ten minutes to hours, a difference of one to two orders of magnitude. This difference in dynamic characteristics across multiple time scales renders simple superposition control strategies completely ineffective. The core contradictions that the control system needs to address manifest in multiple dimensions. First, there is the problem of strong coupling among multiple variables: changing the opening of the extraction steam valve affects multiple parameters such as main steam pressure and reheat steam temperature; adjusting the frequency of the molten salt pump changes the injected steam parameters. Second, there is the complex switching of operating modes: the system needs to switch between various operating conditions such as "pure condensing operation," "heat storage and load reduction," "heat release and load increase," and "hybrid mode."

[0005] The prominent problems currently facing control systems can be summarized in three aspects:

[0006] 1. In terms of dynamic response, traditional PID control is difficult to adapt to a wide range of changing operating conditions. When the unit load command changes rapidly, the main steam pressure fluctuation often exceeds ±0.5MPa and the steam temperature fluctuation exceeds ±10℃.

[0007] 2. In terms of coordination and optimization, existing distributed control systems (DCS) have complex and rigid logic and lack the ability to adaptively adjust to the operating state.

[0008] 3. In terms of safety protection, the control logic and protection system are not linked enough, often "emphasizing protection and neglecting prevention", which increases the risk of unplanned shutdowns.

[0009] These problems severely restrict the full realization of the performance of the coupled system. Therefore, conducting research on the control technology of coal-fired power unit coupled molten salt energy storage system is not only a necessary prerequisite for engineering applications, but also the key to unlocking the potential of this technology. Summary of the Invention

[0010] Objective: In order to overcome the shortcomings of the existing technology, the present invention provides a control method, electronic equipment and storage medium for a deep-tuning thermal-electric coupling molten salt system.

[0011] Technical solution: To solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0012] Firstly, a control method for a thermal power coupled molten salt system under deep adjustment includes the following steps:

[0013] Step 1: Obtain the real-time spot market electricity price D0, turbine regulating stage pressure Pt, measured main steam pressure P1, main steam pressure setpoint P0, and boiler separator pressure Pg at sampling time k.

[0014] Step 2: Obtain the off-peak electricity price D1 and the threshold R.

[0015] Step 3: Calculate the difference between the real-time electricity price D0 and the off-peak electricity price D1 as the first difference, and calculate the difference between the boiler energy signal BD and the heat demand signal HR as the second difference.

[0016] Step 4: If the first difference > 0, it is peak electricity price; or if the second difference > R, switch to molten salt + boiler thermal storage joint operation mode and proceed to Step 5. If the first difference ≤ 0, or the second difference ≤ R, switch to boiler monotonic mode.

[0017] Step 5: Control the thermal power coupled molten salt system through the thermal power-storage joint commissioning mode.

[0018] In a second aspect, a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements a control method for a deep-tuned thermal-electric coupled molten salt system as described in any of the first aspects.

[0019] Thirdly, a computer device comprising:

[0020] Memory is used to store instructions.

[0021] A processor for executing the instructions, causing the computer device to perform operations of a control method for a deep-tuned thermal-electric coupled molten salt system as described in any of the first aspects.

[0022] Beneficial Effects: This invention provides a control method, electronic equipment, and storage medium for a thermal-electric coupling molten salt system under deep adjustment. The method includes classifying the thermal-electric coupling molten salt system into two operating conditions—small deviation and large deviation—by judging the difference between the unit power setpoint and the actual unit power. Based on the start-up conditions and the magnitude of the difference, two modes—energy storage and energy release—are determined. Power is distributed to the molten salt controller and the unit coordination controller via a power distributor. Combined thermal-electric coupling control is achieved by using steam extraction and water extraction as control variables. This invention, through the power distributor and the allocation of operating conditions, enables better tracking control of unit power and main steam pressure. Under molten salt control, the unit power overshoot is significantly reduced, enabling rapid and error-free tracking of load commands. Because molten salt control has minimal impact on unit boiler operation, the main steam pressure fluctuation is smaller, resulting in more stable pressure control and more rapid and stable changes in steam extraction. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of a deep-tuned thermal-electric coupling molten salt system according to the present invention.

[0024] Figure 2 This is a schematic flowchart of a control method for a deep-tuning thermal-electric coupled molten salt system according to the present invention.

[0025] Figure 3A schematic diagram of the response curves of electrical power and main steam pressure under load reduction.

[0026] Figure 4 A schematic diagram of the response curves of air extraction rate, valve opening, and fuel quantity under reduced load. Detailed Implementation

[0027] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0028] The present invention will be further described below with reference to specific embodiments.

[0029] Example 1:

[0030] This embodiment describes a deep-tuned thermal-electric coupling molten salt system, such as... Figure 1 As shown, it includes a boiler system, a steam turbine generator system, a deaerator feedwater system, and a molten salt system.

[0031] The boiler system includes heat exchangers such as economizer, water-cooled wall, steam-water separator, superheater, and reheater.

[0032] The steam turbine generator system includes: a high-pressure cylinder, an intermediate-pressure cylinder, a low-pressure cylinder, and a generator.

[0033] The deoxygenated feedwater system includes: a high-pressure heater, a low-pressure heater, a deaerator, a condenser, and a condensate pump.

[0034] The molten salt system includes: a hot molten salt tank, a cold molten salt tank, a heat storage heat exchanger, and a heat release heat exchanger.

[0035] The working process of the thermal power coupled molten salt system under deep regulation is as follows: During the heat storage process, the 600°C superheater outlet steam enters the heat storage heat exchanger to heat the 290°C cold molten salt in the cold molten salt tank. The hot molten salt heated to 565°C enters the hot molten salt tank for storage. During the heat release process, the bypass feedwater from the high-pressure heater inlet and the feedwater pump outlet enters the heat release heat exchanger. The hot molten salt heats the feedwater and is then fed into the high-pressure heater outlet.

[0036] Example 2:

[0037] This implementation introduces a control method for a thermal-electric coupled molten salt system with deep tuning, such as... Figure 2 As shown, it includes the following steps:

[0038] Step 1: Obtain the real-time spot market electricity price D0, turbine regulating stage pressure Pt, measured main steam pressure P1, main steam pressure setpoint P0, and boiler separator pressure Pg at sampling time k.

[0039] Step 2: Obtain the off-peak electricity price D1 and the threshold R.

[0040] Step 3: Calculate the difference between the real-time electricity price D0 and the off-peak electricity price D1 as the first difference, and calculate the difference between the boiler energy signal BD and the heat demand signal HR as the second difference.

[0041] The expression for the boiler energy signal BD is as follows:

[0042]

[0043] The expression for the heat demand signal (HR) is as follows:

[0044] HR=

[0045] In the formula, C is the boiler heat storage coefficient, d is the differential operator, and t is the time unit.

[0046] Step 4: If the first difference (D0-D1) > 0, then it is peak electricity price; or if the second difference (BD-HR) > R, switch to molten salt + boiler thermal storage joint commissioning mode and proceed to Step 5. If the first difference (D0-D1) ≤ 0, or the second difference (BD-HR) ≤ R, switch to boiler monotonic mode. The threshold R is set to 3%-10%, preferably 5%.

[0047] Step 5: Control the thermal power coupled molten salt system through the thermal power-storage joint commissioning mode.

[0048] Furthermore, the thermal storage and thermal regulation mode includes a thermal storage mode and a thermal release mode, and the specific steps are as follows:

[0049] Step 5.1: Obtain the generator set power setpoint Pref and the actual generator power value P at sampling time k, the current stored heat of molten salt Q1, and the total peak-shaving capacity of molten salt Q0.

[0050] Step 5.2: Calculate the power deviation value ΔP: ΔP=Pref-P, set the positive peak-shaving capacity to the current stored heat Q1, and calculate the negative peak-shaving capacity of molten salt ΔQ: ΔQ=Q0-Q1.

[0051] To protect the safety of the molten salt, the molten salt thermal storage mode is activated when Q1 is higher than 15%, and the molten salt cannot participate in the control when Q1 is lower than 15%, which is the boiler monotonic mode.

[0052] When Q1 is less than 85%, the molten salt heat release mode is activated; when Q1 is greater than 85%, the molten salt cannot participate in the control, and it is in the boiler monotonic mode.

[0053] Step 5.3: Calculate the capacity deviation PQ, PQ=C1 ΔP-ΔQ, C1 is the power-heat equivalent coefficient, taken as 3.6. When ΔP>0 and PQ>0, it is the molten salt exothermic mode, and the molten salt exothermic controller and the boiler controller work simultaneously.

[0054] The controlled variable of the molten salt exothermic controller is PQ, the target is PQ=0, and the controlled variable is the pumping rate. By controlling the pumping rate, the molten salt exothermic effect is changed, the feedwater temperature is changed, and the electrical load is changed to make PQ=0. Since PQ is large, the molten salt adjustment cannot keep up. At the same time, the boiler controller is activated. The controlled variable of the boiler controller is the main steam pressure P1, and the target is for P1 to reach the set value P0. Conventional coordinated control is performed by adjusting the pulverizing system, combustion system, and air volume regulation system to make P1=P0.

[0055] When ΔP>0 and PQ<0, it is in molten salt exothermic mode, and only the molten salt exothermic controller works;

[0056] The controlled variable of the molten salt exothermic controller is PQ, the target is PQ=0, and the controlled variable is the pumping rate. By controlling the pumping rate, the molten salt exothermic effect is changed, the feedwater temperature is changed, and the electrical load is changed to make PQ=0. Since PQ is small, the requirements can be met by adjusting the molten salt alone.

[0057] When ΔP<0 and PQ>0, it is in molten salt thermal storage mode, and the molten salt thermal storage controller and the boiler controller work simultaneously.

[0058] The controlled variable of the molten salt thermal storage controller is PQ, the target is PQ=0, and the controlled variable is the steam extraction rate. By controlling the steam extraction rate, the molten salt thermal storage is increased, and the turbine power generation is reduced, so that PQ=0. Since PQ is large, the molten salt regulation cannot keep up. At the same time, the boiler controller is activated. The controlled variable of the boiler controller is the main steam pressure P1, and the target is for P1 to reach the set value P0. Conventional coordinated control is performed, and P1=P0 is achieved by adjusting the pulverizing system, combustion system, and air volume regulation system.

[0059] When ΔP < 0 and PQ < 0, it is in molten salt thermal storage mode, and only the molten salt thermal storage controller works. The controlled variable of the molten salt thermal storage controller is PQ, the target is PQ = 0, and the control variable is the steam extraction rate. By controlling the steam extraction rate to increase molten salt thermal storage and reduce the turbine power generation, PQ = 0 can be achieved. Since PQ is small, the requirements can be met by molten salt regulation alone.

[0060] Step 5.4: k=k+1, feedback to obtain turbine regulating stage pressure Pt, measured main steam pressure P1, main steam pressure setpoint P0, boiler separator pressure Pg; actual unit power value P, current stored heat of molten salt Q1, repeat steps 1-5, end when PQ=0.

[0061] As the control process cyclically executes, the deviation between the actual output power of the unit and the load command gradually decreases. The combined thermal power and thermal storage system will only experience load tracking through coordinated unit control for a limited period. When the load deviation command decreases to within the peak-shaving capacity of the molten salt thermal storage system, the unit's fuel quantity and main steam valve opening will remain unchanged, with continuous load tracking achieved only through changes in extraction steam and pumped water flow rates. A proportional-integral-derivative controller is employed, and the controller parameters are tuned using the critical proportional gain method, enabling flexible peak-shaving control of the combined thermal power and thermal storage system.

[0062] Example 3:

[0063] This embodiment describes a computer-readable storage medium storing a computer program that, when executed by a processor, implements a control method for a deep-tuning thermal-electric coupled molten salt system as described in any of Embodiment 2.

[0064] Example 4:

[0065] This embodiment describes a computer device, including:

[0066] Memory is used to store instructions.

[0067] A processor is configured to execute the instructions, causing the computer device to perform operations of a control method for a deep-tuned thermal-electric coupled molten salt system as described in any of Embodiment 2.

[0068] Example 5:

[0069] This embodiment takes a thermal power coupled molten salt system as an example. The initial load of the combined thermal power and storage system is 330MW. At t=100s, it is assumed that the unit load command decreases at a ramp rate of 19.8MW / min to 320.1MW and remains constant. At t=1100s, the unit load command continues to decrease at a ramp rate of 9.9MW / min to 310.2MW and then remains constant. The controlled variable response curve of the control system is compared as follows: Figure 3 As shown, the control quantity curve is as follows Figure 4 As shown, a comparison is made between two control schemes: the combined control of fire and storage with the addition of molten salt and the coordinated control without the addition of molten salt.

[0070] It can be seen that the combined thermal and storage control can achieve good tracking and control of unit power and main steam pressure within 50 seconds, but compared to coordinated control, which alone requires about 200 seconds to achieve control of unit power and main steam pressure. Under molten salt control, the unit power overshoot is significantly reduced, with an overshoot of less than 1%, enabling rapid and error-free tracking of load commands. Because molten salt control has less impact on unit boiler operation, the main steam pressure fluctuation is smaller, resulting in more stable pressure control with an overshoot of less than 1%, while the overshoot of coordinated control alone reaches 5%. In addition, the control quantity change curves of coordinated control and molten salt control show that the steam extraction rate changes more rapidly and smoothly than the unit fuel quantity and valve opening.

[0071] The innovation of this invention lies in constructing a thermal power coupled molten salt deep-shaving control system. Based on the unit's power deviation, it classifies operating conditions into large and small deviation modes, accurately determining the dual operation modes of energy storage and energy release. Through a power distributor, it achieves coordinated control between the molten salt system and the unit, using steam extraction and water extraction as precise control variables to realize deep peak shaving through thermal power-storage synergy. This effectively overcomes the technical shortcomings of traditional thermal power plants, such as limited deep-shaving capabilities and lagging power response.

[0072] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0073] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0074] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0075] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0076] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A control method for a deep-tuned thermal-electric coupled molten salt system, characterized in that: Includes the following steps: Step 1: Obtain the real-time spot market electricity price D0, turbine regulating stage pressure Pt, measured main steam pressure P1, main steam pressure setpoint P0, and boiler separator pressure Pg at sampling time k; Step 2: Obtain the off-peak electricity price D1 and the threshold R; Step 3: Calculate the difference between the real-time electricity price D0 and the off-peak electricity price D1 as the first difference, and calculate the difference between the boiler energy signal BD and the heat demand signal HR as the second difference; Step 4: If the first difference is >0, or the second difference is >R, switch to the molten salt + boiler fire-storage joint commissioning mode and proceed to Step 5; Step 5: Control the thermal power coupled molten salt system through the thermal power-storage joint commissioning mode.

2. The control method for a deep-tuned thermal-electric coupled molten salt system according to claim 1, characterized in that: Step 4 further includes: if the first difference is ≤0 or the second difference is ≤R, switch to boiler monotonic mode.

3. A control method for a deep-tuned thermal-electric coupled molten salt system according to claim 1 or 2, characterized in that: The expression for the boiler energy signal BD is as follows: 。 4. A control method for a deep-tuned thermal-electric coupled molten salt system according to claim 1 or 2, characterized in that: The expression for the heat demand signal HR is as follows: HR= ; In the formula, C is the boiler heat storage coefficient, d is the differential operator, and t is the time unit.

5. A control method for a deep-tuned thermal-electric coupled molten salt system according to claim 1 or 2, characterized in that: The threshold R is set to 3%-10%.

6. The control method for a deep-tuned thermal-electric coupled molten salt system according to claim 5, characterized in that: The threshold R is set to 5%.

7. A control method for a deep-tuned thermal-electric coupled molten salt system according to claim 1 or 2, characterized in that: Step 5 specifically includes: Step 5.1: Obtain the generator set power setpoint Pref and the actual generator power value P at sampling time k, the current stored heat of molten salt Q1, and the total peak-shaving capacity of molten salt Q0; Step 5.2: Calculate the power deviation value ΔP, set the positive peak-shaving capacity to the current stored heat Q1, and calculate the negative peak-shaving capacity ΔQ of the molten salt; Step 5.3: Calculate the capacity deviation PQ. When ΔP>0 and PQ>0, it is the molten salt exothermic mode, and the molten salt exothermic controller and the boiler controller work simultaneously. The controlled variable of the molten salt exothermic controller is PQ, the target is PQ=0, and the controlled variable is the pumping volume. The controlled variable PQ is adjusted by controlling the pumping volume. The controlled variable of the boiler controller is the main steam pressure P1, the target is for P1 to reach the set value P0, and the main steam pressure P1 is adjusted by regulating the pulverizing system, the combustion system and the air volume regulation system. When ΔP>0 and PQ<0, it is in molten salt exothermic mode, and only the molten salt exothermic controller works; The controlled variable of the molten salt exothermic controller is PQ, the target is PQ=0, the controlled variable is the pumping rate, and the controlled variable PQ is adjusted by controlling the pumping rate. When ΔP<0 and PQ>0, it is in molten salt thermal storage mode, and the molten salt thermal storage controller and the boiler controller work simultaneously. The controlled variable of the molten salt thermal storage controller is PQ, the target is PQ=0, and the controlled variable is the steam extraction rate. The controlled variable PQ is adjusted by controlling the steam extraction rate. The controlled variable of the boiler controller is the main steam pressure P1, the target is for P1 to reach the set value P0, and the main steam pressure P1 is adjusted by regulating the pulverizing system, the combustion system, and the air volume regulation system. When ΔP<0 and PQ<0, it is in molten salt thermal storage mode, and only the molten salt thermal storage controller works; The controlled variable of the molten salt thermal energy storage controller is PQ, the target is PQ=0, the controlled variable is the steam extraction rate, and the controlled variable PQ is adjusted by controlling the steam extraction rate. Step 5.4: k=k+1, obtain the turbine regulating stage pressure Pt, the measured value of the main steam pressure P1, the set value of the main steam pressure P0, the boiler separator pressure Pg; the actual unit power value P, and the current stored heat of the molten salt Q1. Repeat steps 1-5 until PQ=0.

8. The control method for a deep-tuned thermal-electric coupled molten salt system according to claim 7, characterized in that: The expression for the power deviation value ΔP is as follows: ΔP = Pref - P; The expression for the negative peak-shaving capacity ΔQ of the molten salt is as follows: ΔQ = Q0 - Q1; The expression for the capacity deviation PQ is as follows: PQ=C1 ΔP-ΔQ; In the formula, C1 is the equivalent coefficient of power and heat.

9. A computer-readable storage medium, characterized in that: It stores a computer program, which, when executed by a processor, implements a control method for a deep-tuning thermal-electric coupled molten salt system as described in any one of claims 1-8.

10. A computer device, characterized in that: include: Memory, used to store instructions; A processor for executing the instructions, causing the computer device to perform the operation of a control method for a deep-tuned thermal-electric coupled molten salt system as described in any one of claims 1-8.

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