CN-121993900-A - High-voltage induction heating molten salt system and method for energy storage

Abstract

The application relates to a high-voltage induction heating molten salt system and a method for energy storage, which relate to the technical field of thermal energy storage and comprise a salt storage tank, an induction heating device, a high-voltage power supply module, a circulating pump and a control system. The induction heating device is arranged on a circulating pipeline inside or outside the salt storage tank, the high-voltage power supply module is electrically connected with the induction heating device and used for providing high-voltage high-frequency alternating current, the circulating pump is used for driving molten salt to circulate in the system, and the control system is connected with the high-voltage power supply module and the circulating pump to adjust heating power and flow rate. According to the application, the high-voltage power supply module is used for directly supplying power to the induction heating device, the electromagnetic induction principle is used for generating vortex heat in molten salt or heating body, the problems of scaling and local overheating of the traditional resistance heater are avoided, high-power and high-efficiency molten salt heating can be realized, the heat conversion efficiency and the operation stability of the energy storage system are improved, and the device is suitable for large-scale wind-electricity absorption and industrial heat supply energy storage scenes.

Inventors

• ZHU XIANG
• CHEN XINHUA
• ZHAO JING
• SUN PENG
• HU CHUNTING
• WU XIANG
• HUANG YOUQIANG
• SHI ZHENDONG
• SUN JINGGUO
• HAN SHOUPENG
• LIU CHEN

Assignees

• 华润电力（菏泽）有限公司

Dates

Publication Date

20260508

Application Date

20260305

Claims (10)

1. 1. A high-voltage induction heating molten salt system for energy storage is characterized by comprising a salt storage tank (1) for storing liquid molten salt, an induction heating device (2) comprising an induction coil (21) and a heating body (22) positioned in the electromagnetic field action range of the induction coil (21), wherein the heating body (22) is in contact with the liquid molten salt to perform heat exchange, a high-voltage power supply module (3) is electrically connected with the induction coil (21) and is used for supplying high-voltage alternating current of 10kV or more to the induction coil (21), a circulating pump (4) is arranged on a pipeline connected with the salt storage tank (1) and is used for driving the liquid molten salt to flow, and a control system (5) is respectively in communication connection with the high-voltage power supply module (3) and the circulating pump (4) and is used for controlling power supply and molten salt flow.
2. 2. The high-voltage induction heating molten salt system for energy storage according to claim 1, wherein the induction heating device (2) is arranged outside the salt storage tank (1), the heating element (22) is of a tubular structure, the liquid molten salt flows inside the tubular structure, and the induction coil (21) is arranged outside the tubular structure in a surrounding manner.
3. 3. The high-voltage induction heating molten salt system for energy storage according to claim 2, wherein the heating body (22) is made of a magnetic conduction high-temperature resistant alloy material, a heat preservation and insulation layer (23) is arranged between the outer surface of the heating body (22) and the induction coil (21), and the material of the heat preservation and insulation layer (23) is selected from aerogel felt or aluminum silicate ceramic fiber.
4. 4. The high-voltage induction heating molten salt system for energy storage according to claim 1, wherein the induction heating device (2) is arranged inside the salt storage tank (1), the heating element (22) is a porous conductive ceramic structure arranged at the bottom of the salt storage tank (1), and the induction coil (21) is sealed in a high-temperature resistant insulating sleeve and is inserted into the porous conductive ceramic structure.
5. 5. The high-voltage induction heating molten salt system for energy storage according to claim 1, characterized in that the high-voltage power supply module (3) comprises a high-voltage frequency converter for converting a power frequency high-voltage power into a high-frequency high-voltage alternating current with a frequency of 1kHz-50kHz and outputting the high-frequency high-voltage alternating current to the induction coil (21).
6. 6. The high-voltage induction heating molten salt system for energy storage according to claim 1, further comprising a temperature sensor (6), wherein the temperature sensor (6) is arranged at a molten salt outlet of the induction heating device (2) and is electrically connected with the control system (5), and the control system (5) dynamically adjusts the output frequency or voltage of the high-voltage power supply module (3) by adopting a PID algorithm based on feedback data of the temperature sensor (6).
7. 7. The high-voltage induction heating molten salt system for energy storage according to claim 1, wherein the induction coil (21) is formed by winding a hollow copper pipe, a cooling medium is filled in the hollow copper pipe, and the cooling medium is deionized water or insulating cooling oil.
8. 8. The high-voltage induction heating molten salt system for energy storage according to claim 2, wherein a spiral spoiler is arranged inside the tubular structure, and the spiral spoiler and the heating body (22) are integrally formed or welded and fixed for enhancing turbulence degree of molten salt.
9. 9. A method of high voltage induction heating molten salt for energy storage, characterized in that it is implemented on the basis of the system according to any one of claims 1-8, comprising the steps of: Step S1, a control system (5) starts a circulating pump (4) to enable liquid molten salt to flow through a heating element (22) of an induction heating device (2) from a salt storage tank (1); Step S2, the control system (5) controls the high-voltage power supply module (3) to output high-voltage alternating current to the induction coil (21), and an alternating magnetic field is generated around the induction coil (21); S3, generating vortex by the heating element (22) under the action of an alternating magnetic field, and rapidly heating to transfer heat to the flowing liquid molten salt; And S4, the control system (5) monitors the heated molten salt temperature in real time, and adjusts the output power of the high-voltage power supply module (3) and the rotating speed of the circulating pump (4) according to the target energy storage temperature.
10. 10. The method according to claim 9, characterized in that in step S4, when it is monitored that the molten salt temperature is below the target storage temperature lower limit, the control system (5) preferentially increases the output frequency of the high voltage power supply module (3), and if the upper limit is not met, the rotation speed of the circulation pump (4) is reduced.

Description

High-voltage induction heating molten salt system and method for energy storage Technical Field The invention relates to the technical field of thermal energy storage, in particular to a high-voltage induction heating molten salt system and method for energy storage. Background Along with the transformation of global energy structures and the rapid development of renewable energy sources, the permeability of clean energy sources such as wind energy, solar energy and the like in a power grid is continuously improved. However, these renewable energy sources have significant intermittency and volatility, resulting in a significant challenge in the balance of supply and demand of the grid. In order to effectively absorb the wind and light discarding electric quantity and improve the stability and flexibility of the power grid, a large-scale energy storage technology becomes a hot spot for research and application. Among the energy storage technologies, the fused salt energy storage technology has been widely focused and applied in the fields of solar photo-thermal power generation, power grid peak regulation and frequency modulation, industrial steam heat supply and the like by virtue of the advantages of high energy storage density, long service life, low cost, environmental friendliness and the like. Liquid molten salts (such as nitrates, carbonates or chlorides) are often used as heat transfer and storage media, which need to remain liquid at high temperatures and absorb thermal energy. At present, in an electric heating molten salt energy storage system, a traditional resistance type heating technology is mainly adopted. The resistance heater is usually composed of a resistance wire and a metal sheath, and is directly inserted into a molten salt tank or installed in a pipeline heater, and after the resistance wire is electrified, the resistance wire heats and transfers heat to molten salt through heat conduction. In practical applications, the conventional resistive heating mode mainly has the following background limitations: the surface heat load of the resistance heater is limited, and in order to realize high-power heating with the temperature of tens megawatts to hundreds megawatts, a very large number of heating pipes are required to be installed, so that the complexity of the system is increased, and the occupied area and the initial investment cost of equipment are greatly increased. The resistance heater is directly contacted with high-temperature molten salt, and in the long-term operation process, the molten salt is easy to generate local thermal decomposition or crystallization scaling on the surface of the heating pipe, so that the heat transfer efficiency is rapidly reduced, and even the heating pipe is caused to be burnt out by local overheating, thereby seriously affecting the safety and the service life of the system. In addition, conventional electrical heating systems often require the provision of a bulky step-down transformer to reduce the 10kV or 35kV high voltage of the grid to a low voltage (e.g., 400V or 690V) before the resistive heater can be used, which not only increases transformer losses, but also results in reduced overall energy conversion efficiency. From the existing electric heating molten salt means and the defects, the existing resistance heating method is difficult to directly utilize high-voltage electricity to heat in a high-power and high-efficiency manner, and has the problems of scaling, local overheating, short service life, huge system and the like. Therefore, how to develop a novel molten salt heating system and method which can be directly connected to a high-voltage power grid, avoid scaling failure caused by direct contact of a heating element and molten salt and realize high-power efficient heating becomes a main technical problem to be solved in the field. Disclosure of Invention In order to solve the problems, the application provides a high-voltage induction heating molten salt system and a method for energy storage. In a first aspect, the application provides a high-voltage induction heating molten salt system for energy storage, which adopts the following technical scheme: The high-voltage induction heating molten salt system for energy storage comprises a salt storage tank for storing liquid molten salt, an induction heating device, a high-voltage power supply module, a circulating pump and a control system, wherein the induction heating device comprises an induction coil and a heating body positioned in the electromagnetic field action range of the induction coil, the heating body is in contact with the liquid molten salt to perform heat exchange, the high-voltage power supply module is electrically connected with the induction coil and is used for supplying high-voltage alternating current of 10kV or more to the induction coil, the circulating pump is arranged on a pipeline connected with the salt storage tank and is used for driving the liquid molt