A thermal power unit electric-gas coupling heat storage peak shaving device and a use method thereof

Abstract

The application discloses a thermal power unit electric-steam coupling heat storage peak regulation device and a use method thereof. The thermal power unit electric-steam coupling heat storage peak regulation device comprises a steam coupling electromagnetic heating molten salt heat exchange system and a molten salt energy storage system. The steam coupling electromagnetic heating molten salt heat exchange system comprises a steam coupling electromagnetic heating molten salt heat exchanger, a high-pressure cylinder high-temperature steam inlet, a medium-pressure cylinder medium-high-temperature steam inlet, a low-pressure cylinder low-temperature steam inlet, a valley electricity input port and an intelligent electric-steam monitoring and regulation system. The molten salt energy storage system comprises a molten salt cold tank, a molten salt hot tank, a first molten salt pump, a molten salt-water heat exchanger, a cooling tower, superheated steam and a second molten salt pump. The intelligent electric-steam monitoring and regulation system intelligently coordinates the steam coupling electromagnetic heating molten salt heat exchange system and the molten salt energy storage system. The steam coupling electromagnetic heating molten salt heat exchanger is used to realize steam heating and electromagnetic heating coupling and improve heating efficiency.

Description

Technical Field

[0001] This invention relates to the field of peak shaving technology for thermal power units, specifically to an electric-steam coupled thermal storage peak shaving device for thermal power units and its usage method. Background Technology

[0002] With the large-scale integration of renewable energy into the grid, higher demands are placed on the grid's peak-shaving capacity. However, my country's current power structure, in terms of both installed capacity and power generation, is dominated by thermal power. Therefore, utilizing thermal power units for deep peak shaving remains the primary choice for the current power grid.

[0003] Currently, there are two main methods for achieving deep peak shaving in thermal power units. One is to further reduce the minimum technical output of the unit by modifying the combustion system and steam flow. The other is to equip the thermal power unit with a thermal storage electric boiler. During the paid peak shaving window, the electric boiler consumes electricity for heating, effectively reducing the unit's output and achieving virtual peak shaving for the thermal power unit. However, both of these technical solutions have certain shortcomings. The first technical solution is greatly affected by coal quality and the actual operating conditions of the unit. Low-load operation of the unit increases coal consumption and makes it difficult to meet desulfurization and denitrification targets. The contradiction between the unit's deep peak shaving capacity and the system's operating efficiency and flexibility still exists. The second technical solution is greatly affected by the heating unit and the heating season. The thermal storage electric boiler consumes electricity for heating, and its heat-electricity-heat production process is a low-level recycling of energy. Although it achieves certain economic benefits, it also causes serious resource waste. Therefore, it is necessary to explore solutions that address the contradiction between the thermal power unit's response to the grid's peak shaving needs and the unit's operating efficiency and flexibility, ensuring optimal benefits for the whole society.

[0004] Chinese invention patent application CN108592137A discloses a dual-cylinder decoupling deep peak-shaving system for flexible retrofitting of thermal power plants. This system achieves high-pressure steam de-cooling and pressure reduction through intelligent control of intelligent de-cooling and pressure reducing devices to meet the needs of large-area heating, thereby achieving dual-cylinder decoupling. However, this system loses high-quality energy such as high pressure and high temperature of steam, resulting in low energy conversion efficiency.

[0005] Chinese invention patent application CN109945710A discloses a peak-shaving system for thermal power units based on the combined energy level utilization of low-melting-point salt and water. This invention stores high-grade heat sources in the form of low-melting-point salt, and then exchanges heat energy with water, realizing graded storage and graded utilization of energy. However, this method only realizes single-level thermoelectric decoupling and does not realize flexible peak-shaving of thermal power units.

[0006] Chinese invention patent application CN113452084A discloses a novel flexible peak-shaving system for thermal power plants based on high-temperature thermal storage facilities. This invention designs a system with low operating costs and flexible adjustment by adding high-temperature thermal storage facilities. When the grid's renewable energy generation load is high, the system can reduce the power generation load of thermal power units, making way for the grid to absorb renewable energy and achieving deep peak shaving. When the grid's renewable energy generation load is low, it can quickly increase the power generation capacity of the units, achieving the purpose of providing peak shaving and valley filling services to the grid. However, the high-temperature thermal storage device is not described in detail, and the system process is not closed.

[0007] Chinese invention patent application CN114923165A discloses a flexible retrofit heating system for peak shaving of a unit coupled with phase change thermal storage. The system uses phase change thermal storage to recover the waste heat of flue gas from a coal-fired boiler and then uses it to preheat the cold water entering the boiler, thereby improving the boiler's steam generation efficiency. However, the system only performs peak shaving from the steam boiler side and does not take into account the peak shaving of electricity consumption, making it difficult to achieve deep peak shaving.

[0008] In summary, existing flexible retrofit systems for thermal power units have low energy conversion efficiency, making it difficult to efficiently store high-quality steam energy. Furthermore, the energy storage methods are relatively limited, resulting in low thermal storage efficiency and hindering the cascade utilization of energy. Most retrofit systems only consider the steam boiler or user side, failing to comprehensively address peak shaving through coupling between the two. They are often constrained by the rated power of the equipment, making deep peak shaving difficult. Moreover, most flexible retrofit systems only consider the conversion between off-peak and peak electricity, without delving into the root causes of load changes—the deep coupling of industrial and urban heat and power.

[0009] Therefore, it is necessary to take into account the overall situation of electric-steam coupling thermal storage peak regulation, and to deeply solve the problem of peak-valley power conversion and thermal-electricity decoupling under the premise of realizing energy cascade utilization. Summary of the Invention

[0010] To address the issue of flexibility retrofitting of existing thermal power units, this invention proposes an electro-steam coupled thermal storage peak-shaving device for thermal power units. This device achieves steam heating and electromagnetic heating coupling through a steam-coupled electromagnetic heating molten salt heat exchanger, thereby improving heating efficiency.

[0011] To achieve the above objectives, the present invention adopts the following technical solution: a steam-electric coupling thermal storage peak-shaving device for thermal power units, which includes a steam-coupled electromagnetic heating molten salt heat exchange system and a molten salt energy storage and release system;

[0012] The steam-coupled electromagnetic heating molten salt heat exchange system includes: a steam-coupled electromagnetic heating molten salt heat exchanger, a high-pressure cylinder high-temperature steam inlet, a medium-pressure cylinder medium-high temperature steam inlet, a low-pressure cylinder low-temperature steam inlet, a valley electricity input port, and an intelligent electric steam monitoring and control system;

[0013] High-temperature and high-pressure steam, medium-high temperature and medium-high pressure steam, and low-temperature and low-pressure steam enter the steam-coupled electromagnetic heating molten salt heat exchanger from the high-temperature steam inlet of the high-pressure cylinder, the medium-high temperature steam inlet of the medium-pressure cylinder, and the low-temperature steam inlet of the low-pressure cylinder, respectively. After heat exchange, the heat is stored in the high-temperature molten salt. The off-peak electricity input port provides AC power to the steam-coupled electromagnetic heating molten salt heat exchanger, storing the energy of off-peak electricity in the high-temperature molten salt.

[0014] The molten salt energy storage and release system includes: a molten salt cold tank, a molten salt hot tank, a first molten salt pump, a molten salt-water heat exchanger, a cooling tower, superheated steam, and a second molten salt pump;

[0015] The first molten salt pump pumps the low-temperature molten salt from the molten salt cold tank to the steam-coupled electromagnetic heating molten salt heat exchanger for heating. The molten salt hot tank is used to store the high-temperature molten salt after it has been heated by the steam-coupled electromagnetic heating molten salt heat exchanger. The high-temperature molten salt is pumped from the molten salt hot tank to the molten salt-water heat exchanger by the second molten salt pump. In the molten salt-water heat exchanger, the high-temperature molten salt heats the cooling tower condensate into superheated steam, which is then output to the power generation system to generate electricity. After heat exchange in the molten salt-water heat exchanger, the high-temperature molten salt cools down and becomes low-temperature molten salt, which is then stored in the molten salt cold tank, completing the energy storage and power generation cycle.

[0016] The intelligent electric steam monitoring and control system intelligently coordinates the steam-coupled electromagnetic heating molten salt heat exchange system and the molten salt energy storage and release system.

[0017] Furthermore, steam flow detectors are installed at the high-temperature steam inlet, the high-temperature steam inlet in the intermediate-pressure cylinder, and the low-temperature steam inlet in the low-pressure cylinder. The steam flow detectors monitor the steam flow in real time and adjust the steam flow according to the signal transmitted from the signal line.

[0018] Furthermore, the intelligent electric steam monitoring and control system mainly collects the flow signal from the steam flow detector, the signal from the thermocouple in the steam-coupled electromagnetic heating molten salt heat exchanger, and the signal from the first molten salt pump in the molten salt energy storage and release system. After analysis, it adjusts the magnitude of the AC current, the magnitude of the steam inlet flow, and the power of the first molten salt pump.

[0019] Furthermore, the steam-coupled electromagnetic heating molten salt heat exchanger includes three heat exchangers: a first heat exchanger, a second heat exchanger, and a third heat exchanger.

[0020] The first, second, and third heat exchangers are arranged in a triangular array. High-temperature and high-pressure steam enters from the high-temperature steam inlet of the high-pressure cylinder, passes through the first flow butterfly valve, and then enters the first heat exchanger for heat exchange. After flowing out from the steam outlet at the bottom of the first heat exchanger, it passes through the second flow butterfly valve and mixes with the medium-pressure and medium-high-temperature steam entering from the high-temperature steam inlet of the medium-pressure cylinder and the third flow butterfly valve before entering the second heat exchanger together. After heat exchange in the second heat exchanger, it passes through the fourth flow butterfly valve and mixes with the low-temperature and low-pressure steam entering from the low-temperature steam inlet of the low-pressure cylinder and the fifth flow butterfly valve before entering the third heat exchanger for heat exchange. Finally, it is discharged from the steam outlet of the third heat exchanger.

[0021] Molten salt enters from the main molten salt inlet of the first heat exchanger, exchanges heat with steam through three series heat exchangers and is electromagnetically heated, and then exits from the main molten salt outlet of the third heat exchanger.

[0022] The steam-coupled electromagnetic heating molten salt heat exchanger of the present invention is a stepped steam-coupled electromagnetic heating molten salt heat exchanger, which realizes stepped absorption and storage of steam waste heat, and further improves the recovery efficiency of steam waste energy.

[0023] Furthermore, the steam-coupled electromagnetic heating molten salt heat exchanger also includes: a steam inlet, a flow butterfly valve, a steam nozzle, a steam outlet, a steam injection main pipe, a steam heating chamber, and an outer wall of the heat exchanger;

[0024] The steam inlet and flow butterfly valve are located at the inlet end of the steam injection main pipe, and the steam outlet is located at the outlet end of the steam injection main pipe. The steam injection main pipe is located inside the outer wall of the heat exchanger, and the steam heating chamber is located between the steam injection main pipe and the outer wall of the heat exchanger. An electromagnetic heating device is provided in the steam heating chamber. A molten salt inlet is provided at the inlet of the electromagnetic heating device, and a molten salt outlet is provided at the outlet of the electromagnetic heating device. An AC power socket is provided on the electromagnetic heating device, and an AC power cord is connected to the AC power socket.

[0025] The steam nozzle is located on the steam injection main pipe and is used to inject the steam in the steam injection main pipe onto the electromagnetic heating device to form a heat flow in the steam heating chamber.

[0026] Furthermore, the salt-dissolving heating tube of the electromagnetic heating device is fixed to the fixing plate by a fixing bolt, and the fixing plate is fixed to the outer wall of the heat exchanger.

[0027] Furthermore, the steam nozzles are arranged at an angle, with a total of five steam nozzles arranged along the axial direction of the steam injection main pipe. The spacing between two adjacent steam nozzles is the same, and each steam nozzle forms a 60° angle with the axial direction of the steam injection main pipe. A total of four steam nozzles are arranged in the same horizontal direction, and the tilt direction of the steam nozzles is the same as the direction of the steam flow.

[0028] The steam nozzle has three layers of nozzles, each with the same diameter, arranged in an array of eight, eight, and one nozzles from the outside to the inside.

[0029] Furthermore, steam enters through the steam inlet, then passes through a flow butterfly valve, where its flow rate is adjusted before entering the steam injection main pipe. Under pressure, it is ejected from the steam nozzle, and the jet is ejected at a certain angle to the outer wall of the electromagnetic heating device. The steam then forms a swirling flow in the steam heating chamber and is subsequently discharged through the steam outlet. Molten salt enters the electromagnetic heating device through the molten salt inlet, and its temperature is raised under the dual heating of high-temperature steam convection heat exchange and electromagnetic heating. It is then discharged through the molten salt outlet to the next stage heat exchanger until it is heated to the temperature required for operation.

[0030] Furthermore, the electromagnetic heating device includes: an electromagnetic coil, an insulating material, and a molten salt heating tube, wherein the insulating material is located between the electromagnetic coil and the molten salt heating tube;

[0031] The electromagnetic coils are tightly wound around the molten salt heating tubes in the same direction; the molten salt heating tubes are U-shaped and interconnected, and are generally wound into a circle, enclosing the steam injection main tube and steam nozzle inside the circle. The molten salt heating tubes are fixed to the fixing plate by fixing bolts.

[0032] This invention also provides a method for using the above-mentioned steam-electric coupling thermal storage peak-shaving device for thermal power units. When the device is started, the load monitored by the intelligent steam-electric monitoring and control system is combined with the actual energy storage needs of the user for calculation, and instructions are sent to the steam-coupled electromagnetic heating molten salt heat exchange system and the molten salt energy storage and release system respectively. The specific operation process is divided into two periods: off-peak electricity and peak electricity.

[0033] During off-peak hours: The power generation of thermal power units exceeds the user's required load. At this time, the electrical and thermal loads that the system should provide during peak hours are calculated according to the intelligent electric steam monitoring and control system. Based on the distribution of electrical and thermal loads, combined with the flow signal from the steam flow meter, the signal from the thermocouple in the steam-coupled electromagnetic heating molten salt heat exchanger, and the signal from the first molten salt pump in the molten salt energy storage system, different types of steam are extracted, and instructions are sent to the steam flow meter, the frequency converter power output device, and the first molten salt pump control module respectively; Energy storage step 1: The steam flow meter receives the instruction and sends it to the steam-coupled electromagnetic heating molten salt heat exchanger. The electromagnetic heating molten salt heat exchanger provides different types of steam: high-pressure cylinder, medium-pressure cylinder, and low-pressure cylinder steam, storing steam energy; Energy storage step 2: The frequency converter power output instrument receives instructions from the intelligent electric steam monitoring and control system to adjust the electromagnetic heating device in the steam-coupled electromagnetic heating molten salt heat exchange system, consuming excess electrical energy and storing energy in the high-temperature molten salt; Energy storage step 3: The first molten salt pump receives instructions from the intelligent electric steam monitoring and control system to adjust the molten salt flow rate and begin pumping the molten salt in the molten salt cold tank into the stepped steam-coupled electromagnetic heating molten salt system for heating;

[0034] During peak power periods: When the power generation of thermal power units is less than the load required by users, the required electric and heat loads are calculated according to the intelligent electric and steam monitoring and control system, and the heat and power resources are rationally allocated and instructions are issued. The second molten salt pump is controlled according to the instructions to pump the high-temperature molten salt in the molten salt hot tank into the molten salt-water heat exchanger for heat exchange, generating superheated steam to provide electric and heat loads for users.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] (1) By using a steam-coupled electromagnetic heating molten salt heat exchanger, steam heating and electromagnetic heating are coupled, thus improving heating efficiency.

[0037] (2) The steam-coupled electromagnetic heating molten salt heat exchanger adopts a three-stage design, which realizes the staged absorption and storage of steam waste heat, and further improves the recovery efficiency of steam waste energy.

[0038] (3) Through the intelligent electric steam monitoring and control system and three subsystem modules (steam coupled electromagnetic heating molten salt heat exchange system, molten salt energy storage and release system and intelligent electric steam monitoring and control system), the system parameters are monitored and predicted in real time, and the thermal and electrical loads of each part are adjusted in advance to achieve a deep improvement in the flexibility of the thermal power unit. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the electric-steam coupling thermal storage peak-shaving device for thermal power units according to the present invention;

[0040] Figure 2 This is a schematic diagram of the first stage of the steam-coupled electromagnetic heating molten salt heat exchanger of the present invention;

[0041] Figure 3 This is a top view of the steam-coupled electromagnetic heating molten salt heat exchanger of the present invention;

[0042] Figure 4 This is a schematic diagram of the electromagnetic heating device of the present invention;

[0043] Figure 5 This is a schematic diagram of the molten salt heating tube of the present invention. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0045] This embodiment provides an electric-steam coupling thermal storage peak-shaving device for thermal power units, such as... Figure 1 As shown, it consists of a steam-coupled electromagnetic heating molten salt heat exchange system 1 and a molten salt energy storage and release system 2.

[0046] The steam-coupled electromagnetic heating molten salt heat exchange system 1 includes: a steam-coupled electromagnetic heating molten salt heat exchanger 11, a high-pressure cylinder high-temperature steam inlet 12, a medium-pressure cylinder medium-high temperature steam inlet 13, a low-pressure cylinder low-temperature steam inlet 14, a valley electricity input port 15, a steam flow detector 16, an intelligent electric steam monitoring and control system 17, a frequency converter power output device 18, a molten salt tube 19, and a signal line 110.

[0047] High-temperature and high-pressure steam, medium-high temperature and medium-high pressure steam, and medium-low temperature and low-pressure steam generated from the steam boiler of the thermal power unit enter the steam-coupled electromagnetic heating molten salt heat exchanger 11 through the high-temperature steam inlet 12 of the high-pressure cylinder, the medium-high temperature steam inlet 13 of the medium-pressure cylinder, and the low-temperature steam inlet 14 of the low-pressure cylinder, respectively. After heat exchange, the heat is stored in the high-temperature molten salt. The off-peak electricity input port 15 provides AC power to the steam-coupled electromagnetic heating molten salt heat exchange system 1. The frequency converter 18 converts the 380V-20Hz electricity into a high-frequency current of 10-30KHz and outputs it to the steam-coupled electromagnetic heating molten salt heat exchanger 11, storing the energy of the off-peak electricity in the high-temperature molten salt. The steam flow detector 16 is located at the high-temperature steam inlet 12 of the high-pressure cylinder, the medium-high temperature steam inlet 13 of the medium-pressure cylinder, and the low-temperature steam inlet 14 of the low-pressure cylinder, monitoring the steam flow in real time and adjusting the steam flow according to the signal transmitted from the signal line 110. The intelligent electric steam monitoring and control system 17 mainly collects the flow signal of the steam flow detector 16, the signal of the thermocouple in the steam coupled electromagnetic heating molten salt heat exchanger 11, and the signal of the first molten salt pump 23 in the molten salt energy storage and release system 2. After analysis, it adjusts the magnitude of the AC current, the magnitude of the steam inlet flow, and the power of the first molten salt pump 23 to intelligently coordinate the various parts.

[0048] The molten salt energy storage and release system 2 includes: a molten salt cold tank 21, a molten salt hot tank 22, a first molten salt pump 23, a molten salt-water heat exchanger 24, a cooling tower 25, superheated steam 26, and a second molten salt pump 27.

[0049] The first molten salt pump 23 pumps the low-temperature molten salt in the molten salt cold tank 21 to the steam-coupled electromagnetic heating molten salt heat exchange system 1 for heating; the molten salt hot tank 22 stores the heated high-temperature molten salt (560°C), and the high-temperature molten salt is pumped from the molten salt hot tank by the second molten salt pump 27 to the molten salt-water heat exchanger 24. The high-temperature molten salt heats the condensate of the cooling tower 25 into superheated steam in the molten salt-water heat exchanger 24, and the superheated steam 26 is output to the power generation system to generate electricity; after the high-temperature molten salt exchanges heat in the molten salt-water heat exchanger 24, its temperature decreases and it becomes low-temperature molten salt, which is stored in the molten salt cold tank 21, completing the energy storage and power generation cycle.

[0050] When the above-mentioned thermal power unit’s electric-steam coupling heat storage peak-shaving device is turned on, according to the load monitored by the intelligent electric-steam monitoring and control system 17 and the system’s forward-looking calculation, instructions are sent to the two systems respectively. The specific operation process can be divided into two periods: off-peak electricity and peak electricity.

[0051] During off-peak electricity periods: The power generation of thermal power units exceeds the user's required load (supply exceeds demand). At this time, the intelligent electric steam monitoring and control system 17 calculates the electrical and heat load that the system should provide during peak electricity periods. Based on the allocation of electrical and heat loads, combined with the flow signal from the steam flow meter 16, the thermocouple signal from the steam-coupled electromagnetic heating molten salt heat exchanger 11, and the signal from the first molten salt pump 23 in the molten salt energy storage system 2, different types of steam are extracted, and instructions are sent to the steam flow meter 16, the frequency converter power output device 18, and the control module of the first molten salt pump 23, respectively. Step 1: The steam flow meter 16 receives the instruction and provides different types of steam to the steam-coupled electromagnetic heating molten salt heat exchanger 11: high-pressure cylinder, medium-pressure cylinder, and low-pressure cylinder, storing the steam energy. Step 2: The frequency converter power output device 18 receives the instruction from the intelligent electric steam monitoring and control system 17 and adjusts the electromagnetic heating device in the steam-coupled electromagnetic heating molten salt heat exchanger 11 to consume excess electrical energy and store energy in the high-temperature molten salt. Step 3: The first molten salt pump 23 receives instructions from the intelligent electric steam monitoring and control system 17, adjusts the molten salt flow rate, and begins to pump the molten salt in the molten salt cold tank 21 into the steam-coupled electromagnetic heating molten salt system 1 for heating.

[0052] During peak power periods: When the power generation of thermal power units is less than the load required by users (supply exceeds demand), the required electrical and thermal loads are calculated based on the intelligent power and steam monitoring and control system 17, and thermal and power resources are rationally allocated and instructions are issued. The second molten salt pump 27, according to the instructions, pumps the high-temperature molten salt in the molten salt hot tank 22 into the molten salt-water heat exchanger 24 for heat exchange, generating superheated steam to provide electrical and thermal loads for users.

[0053] Specifically, the steam-coupled electromagnetic heating molten salt heat exchanger 11 includes a three-stage heat exchanger, such as... Figure 3 As shown, the components are: first heat exchanger 1116, second heat exchanger 1117, third heat exchanger 1118, first flow butterfly valve 1119, second flow butterfly valve 1120, third flow butterfly valve 1121, fourth flow butterfly valve 1122, fifth flow butterfly valve 1123, molten salt inlet 1124, and molten salt outlet 1125.

[0054] The first heat exchanger 1116, the second heat exchanger 1117, and the third heat exchanger 1118 are arranged in a triangular array. High-temperature, high-pressure steam enters from the high-temperature steam inlet 12 of the high-pressure cylinder, passes through the first flow butterfly valve 1119, and then enters the first heat exchanger 1116 for heat exchange. It then flows out from the steam outlet at the bottom of the first heat exchanger and passes through the second flow butterfly valve 1120, where it mixes with medium-high temperature and medium-high pressure steam entering from the high-temperature steam inlet 13 of the medium-pressure cylinder and the third flow butterfly valve 1121 before entering the second heat exchanger 1117. After heat exchange in the second heat exchanger 1117, it passes through the fourth flow butterfly valve 1122 and mixes with medium-low temperature and low-pressure steam entering from the low-temperature steam inlet 14 of the low-pressure cylinder and the fifth flow butterfly valve 1123 before entering the third heat exchanger 1118 for heat exchange. Finally, it is discharged through the steam outlet 114. Similarly, molten salt enters from the molten salt main inlet 1124, passes through three series-connected heat exchangers for heat exchange with steam, and is electromagnetically heated before being discharged from the molten salt main outlet 1125.

[0055] Specifically, the first heat exchanger 1116 in the steam-coupled electromagnetic heating molten salt heat exchanger 11 is as follows: Figure 2 As shown, it includes: a steam inlet 111, a flow butterfly valve 112, a steam nozzle 113, a steam outlet 114, a molten salt outlet 115, a molten salt inlet 116, an electromagnetic heating device 117, a fixing bolt 118, a fixing plate 119, an AC power socket 1110, an AC power cord 1111, a steam injection main pipe 1112, a steam heating chamber 1113, and an outer wall 1114 of the heat exchanger. The main structures of the second heat exchanger 1117 and the third heat exchanger 1118 are the same as those of the first heat exchanger 1116.

[0056] Steam inlet 111 provides an inlet for steam of different qualities, leading to the steam injection main pipe 1112; flow butterfly valve 112 is used to monitor and regulate the flow rate of steam; steam nozzle 113 is used to inject steam from the steam injection main pipe 1112 onto the electromagnetic heating device 117, forming a heat flow in the steam heating chamber 1113; steam outlet 114 is the outlet for heated steam; molten salt outlet 115 provides an outlet for heated high-temperature molten salt; molten salt inlet 116 provides an inlet for molten salt to enter the steam-coupled electromagnetic heating molten salt heat exchanger 11; electromagnetic heating device 117 is used to control the alternating current of the electromagnetic coil. Molten salt is heated under a magnetic field; a fixing bolt 118 is used to fix the heating tube to the fixing plate 119; the fixing plate 119 is used to fix the electromagnetic heating device 117 inside the heat exchanger; an AC power socket 1110 is used to supply AC power from outside the heat exchanger to the electromagnetic coil; an AC power cord 1111 is used to provide AC power to the heat exchanger; a steam injection main pipe 1112 is used to integrate the steam entering from the steam inlet 111; a steam heating chamber 1113 is used to carry the high-temperature steam ejected from the steam nozzle 113 to heat the electromagnetic heating device 117; and an outer wall 1114 of the heat exchanger is used to isolate heat loss and provide space for heat exchange.

[0057] Specifically, the steam nozzles 113 are arranged at an angle. A total of five steam nozzles 113 are arranged along the axial direction of the steam injection main pipe 1112. The spacing between two adjacent steam nozzles 113 is the same, and each steam nozzle 113 forms a 60° angle with the axial direction of the steam injection main pipe 1112. A total of four steam nozzles 113 are arranged at the same horizontal position. The tilt direction of the steam nozzles 113 is the same as the direction of the steam flow. This can ensure smooth steam output. Due to the existence of the angle, a high-temperature steam heating vortex can be formed in the steam heating chamber 1113, thereby enhancing the heat exchange capacity of the steam.

[0058] Specifically, the steam nozzle 113 has three layers of nozzles, each with the same diameter, arranged from the outside to the inside with 8, 8, and 1 nozzles respectively, forming an array.

[0059] Specifically, the electromagnetic heating device 117 includes an electromagnetic coil 1171, an insulating material 1172, and a molten salt heating tube 1173, such as... Figure 4 As shown. The electromagnetic coil 1171 generates an alternating magnetic field, causing the electromagnetic heating device 117 to generate eddy currents and heat. The insulating material 1172 maintains insulation, ensuring water-electricity separation. The molten salt heating tube 1173 heats the molten salt under the alternating magnetic field of the electromagnetic coil. The electromagnetic coil is tightly wound in the same direction around the molten salt heating tube, which is a U-shape that can be interconnected. The overall arrangement is circular, enclosing the main steam injection pipe and steam nozzle within the circle. Figure 5 As shown, the molten salt heating tube 1173 is fixed to the fixing plate 119 by the fixing bolt 118, and the fixing plate 119 is fixed to the outer wall 1114 of the heat exchanger.

[0060] Steam enters through steam inlet 111, then passes through flow butterfly valve 112, where its flow rate is adjusted before entering steam injection main pipe 1112. Under pressure, it is ejected from steam nozzle 113, and the jet is ejected at a certain angle to the outer wall of electromagnetic heating device 117. The steam then forms a swirling flow in steam heating chamber 1113 and is subsequently discharged at steam outlet 114. Molten salt enters electromagnetic heating device 117 from molten salt outlet 115. The molten salt then experiences a temperature increase under the dual heating of high-temperature steam convection heat exchange and electromagnetic heating, and is subsequently discharged from molten salt outlet to the next stage heat exchanger until it is heated to the temperature required for operation.

[0061] The power unit's electro-steam coupling thermal storage peak-shaving device described in this embodiment is used as follows:

[0062] When the power unit’s electric-steam coupling thermal storage peak-shaving device is activated, the intelligent electric-steam monitoring and control system 17 monitors the load and performs forward-looking calculations, and issues commands to the steam-coupled electromagnetic heating molten salt heat exchange system and the molten salt energy storage and release system, respectively. The specific operation process can be divided into two periods: off-peak electricity and peak electricity.

[0063] During off-peak hours: The power generation of thermal power units exceeds the user's required load (at this time, the monitored power generation is 50MW, the user's required load is 20MW, and the surplus energy is 30MW). The intelligent power monitoring and control system 17 calculates that the system needs to provide an electrical load of 80MW (including a heat load of 10MW) during peak hours. Based on the calculation, the electromagnetic heating device consumes electrical energy (10MW) to heat the molten salt, and extracts 500kg / s of high-pressure high-temperature steam and 500kg / s of medium-low temperature steam to the steam-coupled electromagnetic heating molten salt heat exchanger (the amount of steam required for 20MW of power). Step 1: The steam flow detector 16 receives the instruction and provides different types of steam to the steam-coupled electromagnetic heating molten salt heat exchanger 11: high-temperature high-pressure steam, medium-high temperature and medium-high pressure steam, and low-temperature low-pressure steam, storing the steam energy. Step 2: The variable frequency power output device 18 receives the instruction from the intelligent power monitoring and control system 17 and adjusts the electromagnetic heating device in the steam-coupled electromagnetic heating molten salt heat exchanger system 1 to consume excess electrical energy and store the energy in the high-temperature molten salt. Step 3: The first molten salt pump 23 receives instructions from the intelligent electric steam monitoring and control system 17, adjusts the molten salt flow rate, and begins to pump the molten salt in the molten salt cold tank 21 into the steam-coupled electromagnetic heating molten salt system 1 for heating.

[0064] During peak power periods: The power generation of thermal power units is less than the user's required load (at this time, the monitored power generation is 50MW, the user's required load is 80MW, and the energy difference is 30MW). At this time, the required electrical load (70MW) and thermal load (10MW) are calculated according to the intelligent electric steam monitoring and control system 17. The thermal and power resources are rationally allocated and instructions are issued. The second molten salt pump 27, according to the instructions, pumps the high-temperature molten salt in the molten salt hot tank 22 into the molten salt-water heat exchanger 24 for heat exchange, generating superheated steam to provide the user with electrical and thermal loads, realizing the scheme of storing energy during off-peak hours and releasing energy during peak power periods.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A power-steam coupling thermal storage peak-shaving device for thermal power units, characterized in that, It includes a steam-coupled electromagnetic heating molten salt heat exchange system (1) and a molten salt energy storage and release system (2); The steam-coupled electromagnetic heating molten salt heat exchange system (1) includes: a steam-coupled electromagnetic heating molten salt heat exchanger (11), a high-pressure cylinder high-temperature steam inlet (12), a medium-pressure cylinder medium-high temperature steam inlet (13), a low-pressure cylinder low-temperature steam inlet (14), a valley electricity input port (15), and an intelligent electric steam monitoring and control system (17); High-temperature and high-pressure steam, medium-high temperature and medium-high pressure steam, and low-temperature and low-pressure steam enter the steam-coupled electromagnetic heating molten salt heat exchanger (11) from the high-pressure cylinder high-temperature steam inlet (12), the medium-pressure cylinder medium-high temperature steam inlet (13), and the low-pressure cylinder low-temperature steam inlet (14), respectively. After heat exchange, the heat is stored in the high-temperature molten salt. The off-peak electricity input port (15) provides AC power to the steam-coupled electromagnetic heating molten salt heat exchanger (11) and stores the energy of the off-peak electricity in the high-temperature molten salt. The molten salt energy storage and release system (2) includes: a molten salt cold tank (21), a molten salt hot tank (22), a first molten salt pump (23), a molten salt-water heat exchanger (24), a cooling tower (25), superheated steam (26), and a second molten salt pump (27); The first molten salt pump (23) pumps the low-temperature molten salt in the molten salt cold tank (21) to the steam-coupled electromagnetic heating molten salt heat exchanger (11) for heating; the molten salt hot tank (22) is used to store the high-temperature molten salt after being heated by the steam-coupled electromagnetic heating molten salt heat exchanger (11). The high-temperature molten salt is pumped from the molten salt hot tank by the second molten salt pump (27) to the molten salt-water heat exchanger (24). The high-temperature molten salt heats the condensate of the cooling tower (25) into superheated steam in the molten salt-water heat exchanger (24). The superheated steam (26) is output to the power generation system to generate electricity; after the high-temperature molten salt exchanges heat in the molten salt-water heat exchanger (24), its temperature decreases and it becomes low-temperature molten salt. The low-temperature molten salt is stored in the molten salt cold tank (21) to complete the energy storage and power generation cycle; The intelligent electric steam monitoring and control system (17) intelligently coordinates the steam coupling electromagnetic heating molten salt heat exchange system (1) and the molten salt energy storage and release system (2); The steam-coupled electromagnetic heating molten salt heat exchanger (11) includes: a steam inlet (111), a flow butterfly valve (112), a steam nozzle (113), a steam outlet (114), a steam injection main pipe (1112), a steam heating chamber (1113), and an outer wall of the heat exchanger (1114); A steam inlet (111) and a flow butterfly valve (112) are located at the inlet end of the steam injection main pipe (1112), and a steam outlet (114) is located at the outlet end of the steam injection main pipe (1112). The steam injection main pipe (1112) is located inside the outer wall (1114) of the heat exchanger, and the steam heating chamber (1113) is located between the steam injection main pipe (1112) and the outer wall (1114) of the heat exchanger. An electromagnetic heating device (117) is provided inside the steam heating chamber (1113). A molten salt inlet (116) is provided at the inlet of the electromagnetic heating device (117), and a molten salt outlet (115) is provided at the outlet of the electromagnetic heating device (117). An AC power socket (1110) is provided on the electromagnetic heating device (117), and an AC power cord (1111) is connected to the AC power socket (1110). A steam nozzle (113) is installed on a steam injection pipe (1112) to inject steam from the steam injection pipe (1112) onto an electromagnetic heating device (117) to form a heat flow in the steam heating chamber (1113).

2. The power generation unit electric-steam coupling thermal storage peak-shaving device according to claim 1, characterized in that, Steam flow detectors (16) are provided at the high-temperature steam inlet (12), the high-temperature steam inlet (13) in the medium-pressure cylinder, and the low-temperature steam inlet (14) in the low-pressure cylinder. The steam flow detectors (16) monitor the steam flow in real time and adjust the steam flow according to the signal transmitted from the signal line (110).

3. The power generation unit electric-steam coupling thermal storage peak-shaving device according to claim 2, characterized in that, The intelligent electric steam monitoring and control system (17) collects the flow signal from the steam flow detector (16), the thermocouple signal from the steam coupled electromagnetic heating molten salt heat exchanger (11), and the signal from the first molten salt pump (23) in the molten salt energy storage and release system (2). After analysis, it adjusts the magnitude of the AC current, the magnitude of the steam inlet flow, and the magnitude of the power of the first molten salt pump (23).

4. The power generation unit electric-steam coupling thermal storage peak-shaving device according to claim 1, characterized in that, The steam-coupled electromagnetic heating molten salt heat exchanger (11) includes three heat exchangers, namely a first heat exchanger (1116), a second heat exchanger (1117) and a third heat exchanger (1118). The first heat exchanger (1116), the second heat exchanger (1117), and the third heat exchanger (1118) are arranged in a triangular array. High-temperature and high-pressure steam enters from the high-temperature steam inlet (12) of the high-pressure cylinder, passes through the first flow butterfly valve (1119), and then enters the first heat exchanger (1116) for heat exchange. After flowing out from the steam outlet at the bottom of the first heat exchanger, it passes through the second flow butterfly valve (1120) and mixes with the medium-pressure and medium-high temperature steam entering from the high-temperature steam inlet (13) of the medium-pressure cylinder and the third flow butterfly valve (1121) before entering the second heat exchanger (1117). After heat exchange in the second heat exchanger (1117), it passes through the fourth flow butterfly valve (1122) and mixes with the low-temperature and low-pressure steam entering from the low-temperature steam inlet (14) of the low-pressure cylinder and the fifth flow butterfly valve (1123) before entering the third heat exchanger (1118) for heat exchange. Finally, it is discharged from the steam outlet (114) of the third heat exchanger (1118). Molten salt enters from the molten salt inlet (1124) of the first heat exchanger (1116), exchanges heat with steam through three series heat exchangers and is electromagnetically heated, and is discharged from the molten salt outlet (1125) of the third heat exchanger (1118).

5. The power generation unit electro-steam coupling thermal storage peak-shaving device according to claim 1, characterized in that, The molten salt heating tube of the electromagnetic heating device (117) is fixed to the fixing plate (119) by the fixing bolt (118), and the fixing plate (119) is fixed to the outer wall (1114) of the heat exchanger.

6. The power generation unit electric-steam coupling thermal storage peak-shaving device according to claim 1, characterized in that, The steam nozzles (113) are arranged at an angle. A total of five steam nozzles (113) are arranged along the axial direction of the steam injection main pipe (1112). The spacing between two adjacent steam nozzles (113) is the same, and each steam nozzle (113) forms a 60° angle with the axial direction of the steam injection main pipe (1112). A total of four steam nozzles (113) are arranged in the same horizontal direction. The tilt direction of the steam nozzles (113) is the same as the direction of the steam flow. The steam nozzle (113) has three layers of nozzles arranged on it. Each nozzle has the same diameter and there are 8, 8 and 1 nozzles arranged from the outside to the inside, forming an array.

7. The power generation unit electric-steam coupling thermal storage peak-shaving device according to claim 1, characterized in that, Steam enters through the steam inlet (111), and after the flow rate is adjusted by the flow butterfly valve (112), it enters the steam injection main pipe (1112), and then is ejected from the steam nozzle (113) under pressure. The jet is ejected at a certain angle to the outer wall of the electromagnetic heating device (117). Then the steam forms a swirling flow in the steam heating chamber (1113) and is discharged at the steam outlet (114). Molten salt enters the electromagnetic heating device (117) from the molten salt inlet (116). Then the molten salt is heated to a higher temperature by the dual heating of high-temperature steam convection heat exchange and electromagnetic heating. Then it is discharged at the molten salt outlet (115) to the next stage heat exchanger until it is heated to the temperature that meets the operating conditions.

8. The power generation unit electric-steam coupling thermal storage peak-shaving device according to claim 7, characterized in that, The electromagnetic heating device (117) includes: an electromagnetic coil (1171), an insulating material (1172), and a molten salt heating tube (1173), wherein the insulating material (1172) is located between the electromagnetic coil (1171) and the molten salt heating tube (1173); The electromagnetic coil (1171) is tightly wound around the molten salt heating tube (1173) in the same direction; the molten salt heating tube (1173) is an interconnected U-shape, which is generally wound into a circle, surrounding the steam injection main tube (1112) and the steam nozzle (113) inside the circle, and the molten salt heating tube (1173) is fixed to the fixing plate (119) by the fixing bolt (118).

9. The method of using the power generation and steam-electric coupling thermal storage peak-shaving device according to any one of claims 1-8, characterized in that, When the device is put into operation, the load is monitored by the intelligent electric steam monitoring and control system (17) and the actual energy storage needs of the user are calculated. Instructions are sent to the steam-coupled electromagnetic heating molten salt heat exchange system and the molten salt energy storage system respectively. The specific operation process is divided into two periods: valley electricity and peak electricity. During off-peak hours: The power generation of thermal power units is greater than the load required by users. At this time, the electrical load and heat load that the system should provide during peak hours are calculated according to the intelligent electric steam monitoring and control system (17). Based on the allocation of electrical load and heat load, combined with the flow signal of the steam flow meter (16), the thermocouple signal in the steam coupled electromagnetic heating molten salt heat exchanger (11), and the signal of the first molten salt pump (23) in the molten salt energy storage and release system (2), the amount of steam of different properties is extracted and instructions are sent to the control modules of the steam flow meter (16), the frequency converter power output instrument (18), and the first molten salt pump (23) respectively; Step 1: The steam flow meter (16) receives instructions Different types of steam are supplied to the steam-coupled electromagnetic heating molten salt heat exchanger (11): high-pressure cylinder, medium-pressure cylinder and low-pressure cylinder steam, and the steam energy is stored; Step 2: The frequency converter power output instrument (18) receives the instruction from the intelligent electric steam monitoring and control system (17) and adjusts the electromagnetic heating device in the steam-coupled electromagnetic heating molten salt heat exchanger system (1) to consume excess electric energy and store energy in the high-temperature molten salt; Step 3: The first molten salt pump (23) receives the instruction from the intelligent electric steam monitoring and control system (17) and adjusts the molten salt flow rate, and starts to pump the molten salt in the molten salt cold tank (21) into the stepped steam-coupled electromagnetic heating molten salt heat exchanger system (1) for heating; Peak power period: The power generation of thermal power units is less than the load required by users. At this time, the required electrical load and heat load are calculated according to the intelligent electric steam monitoring and control system (17), and the thermal power resources are reasonably allocated and instructions are issued. The second molten salt pump (27) controls the pumping of high temperature molten salt in the molten salt hot tank (22) into the molten salt-water heat exchanger (24) for heat exchange, generating superheated steam to provide electrical load and heat load for users.

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