Fused salt heat storage system and method coupled with green electricity heating and power generation system

Abstract

The invention belongs to the field of fused salt power generation, and relates to a fused salt heat storage system and method coupled with green electricity heating and a power generation system, which can efficiently utilize green electricity and form stored energy, so that a power grid reuses the stored energy when the electricity consumption is relatively high. According to the technical scheme, the device comprises a first low-temperature storage tank, an electric heating module, a first high-temperature storage tank and a heater. And low-temperature fused salt is stored in the first low-temperature storage tank. The electric heating module is electrically connected with the green power supply end, and the pipeline input end of the electric heating module communicates with the first low-temperature storage tank. And high-temperature fused salt is stored in the first high-temperature storage tank. The input end of the mixer is communicated with the pipeline output end of the electric heating module and the output end of the first high-temperature storage tank, the mixer uniformly mixes the fused salt from the electric heating module and the fused salt from the first high-temperature storage tank, and the uniformly mixed fused salt is at a first temperature. And the heater is communicated with the mixer, and the heater is configured to receive the uniformly mixed molten salt from the mixer and heat the uniformly mixed molten salt to a second temperature.

Description

Technical Field

[0001] The present invention belongs to the field of molten salt power generation, and relates to a molten salt heat storage system, method and power generation system coupled with green electricity heating. Background Art

[0002] Molten salt power generation is a power generation technology that uses molten salt as a heat transfer and heat storage medium. Generally, solar energy can be used to heat the molten salt. In addition to meeting the normal power generation during the day when there is sufficient sunshine, it can also take into account power generation at night.

[0003] Based on the good heat storage performance of molten salt, molten salt heat storage can be used as a storage supplement for the power grid, which in turn compensates for the power shortage problem during peak power consumption of the power grid.

[0004] At present, my country's green power has achieved rapid development, such as solar energy and wind energy. In particular, the large-scale deployment of distributed photovoltaic power stations in recent years has caused a large difference in power consumption between day and night in the power grid system. In addition, solar energy and wind energy are unstable, resulting in large fluctuations in photovoltaic or wind power, which often require rectification, inversion and other processes before grid connection, resulting in a waste of electricity. Summary of the invention

[0005] In order to overcome the defects in the above-mentioned related technologies, on the one hand, some embodiments of the present invention propose a molten salt heat storage system coupled with green electricity heating, which can efficiently utilize green electricity and form energy storage, so that the stored energy can be reused when the power consumption of the power grid is high.

[0006] The molten salt heat storage system coupled with green electricity heating includes: a first low-temperature storage tank, an electric heating module, a first high-temperature storage tank and a heater. Among them, the first low-temperature storage tank stores low-temperature molten salt. The power supply end of the electric heating module is electrically connected to the green electricity supply end, and the pipeline input end of the electric heating module is connected to the first low-temperature storage tank. High-temperature molten salt is stored in the first high-temperature storage tank. The input end of the mixer is connected to the pipeline output end of the electric heating module and the output end of the first high-temperature storage tank. The mixer mixes the molten salt from the electric heating module and the molten salt from the first high-temperature storage tank evenly, and makes the mixed molten salt be a first temperature. The heater is connected to the mixer, and the heater is configured to receive the mixed molten salt from the mixer and heat the mixed molten salt to a second temperature.

[0007] Preferably, the molten salt heat storage system coupled with green electricity heating further comprises a second high-temperature storage tank. The second high-temperature storage tank is disposed between the mixer and the heater, and is configured to store the uniformly mixed molten salt and regulate the injection rate of the uniformly mixed molten salt into the heater to be stable.

[0008] Preferably, the molten salt heat storage system coupled with green electricity heating further comprises a third high temperature storage tank. The third high temperature storage tank is connected to the outlet end of the heater, and the outlet end of the heater is also connected to the first high temperature storage tank.

[0009] Preferably, the molten salt heat storage system coupled with green electricity heating also includes: a first temperature sensor, a second temperature sensor and a variable frequency molten salt pump. The first temperature sensor is arranged at the outlet end of the electric heating module, and the first temperature sensor is configured to monitor the real-time temperature of the outlet end of the electric heating module. The second temperature sensor is arranged at the outlet end of the mixer, and the second temperature sensor is configured to monitor the real-time temperature of the outlet end of the mixer. The variable frequency molten salt pump is arranged on the pipeline between the first high temperature storage tank and the mixer, and the variable frequency molten salt pump is configured to control the injection amount of the molten salt in the first high temperature storage tank into the mixer according to the data collected by the first temperature sensor.

[0010] Preferably, the heater comprises a gas-fired molten salt furnace. The molten salt heat storage system coupled with green electricity heating further comprises a first air preheater. The first air preheater is connected to the exhaust port of the gas-fired molten salt furnace, and the first air preheater is arranged between the first low-temperature storage tank and the electric heating module, and the first air preheater is configured to preheat the low-temperature molten salt transported from the first low-temperature storage tank to the electric heating module.

[0011] Preferably, the molten salt heat storage system coupled with green electricity heating further includes: a second cryogenic storage tank and a second air preheater. The second cryogenic storage tank stores low-temperature molten salt, and the outlet end of the second cryogenic storage tank is connected to the inlet end of the mixer. A second air preheater is provided between the second cryogenic storage tank and the mixer, and the second air preheater is configured to preheat the low-temperature molten salt transported from the second cryogenic storage tank to the mixer.

[0012] On the other hand, some embodiments of the present invention also provide a molten salt power generation system coupled with green electricity heating. The molten salt power generation system coupled with green electricity heating comprises: a molten salt heat storage system coupled with green electricity heating, a steam generation system and a steam turbine as described in the above one aspect. The inlet end of the molten salt pipeline of the steam generation system is connected to the second high-temperature storage tank of the molten salt heat storage system coupled with green electricity heating, and the outlet end of the molten salt pipeline of the steam generation system is connected to the first low-temperature storage tank and the second low-temperature storage tank. The steam turbine is connected to the steam generation system.

[0013] On the other hand, some embodiments of the present invention further provide a molten salt heat storage method coupled with green electricity heating, which is applicable to the molten salt heat storage system coupled with green electricity heating described in the above aspect.

[0014] The molten salt heat storage method coupled with green electricity heating includes: after transforming green electricity to a safe voltage range, heating a fixed amount of low-temperature molten salt within a unit time period to obtain electrically heated molten salt. According to the temperature of the electrically heated molten salt and the temperature of the first high-temperature molten salt, a suitable amount of the first high-temperature molten salt and the electrically heated molten salt are mixed to obtain a mixed molten salt, and the mixed molten salt maintains a temperature of the first temperature. The mixed molten salt is continuously heated to obtain high-temperature molten salt and stored.

[0015] Preferably, the molten salt heat storage system coupled with green electricity heating further comprises a second high-temperature storage tank. The method of further heating the mixed molten salt to obtain high-temperature molten salt and storing it is as follows: storing the mixed molten salt in the second high-temperature storage tank. Extracting the mixed molten salt from the second high-temperature storage tank at a stable speed. Heating the extracted mixed molten salt to obtain high-temperature molten salt and storing it.

[0016] The beneficial effects of the present invention are: The electric heating module can adapt to voltage and current fluctuations within the safe voltage range and heat the low-temperature molten salt, so as to achieve efficient utilization of electricity with large fluctuations and inconvenient for direct use. At the same time, combined with the molten salt energy storage method, it can realize power generation during peak power consumption of the power grid, which can reduce the waste of green electricity and cooperate with the role of power grid regulation.

[0017] In view of the instability of green electricity, there is an instability in the heating power of low-temperature molten salt. The method of mixing the first high-temperature storage tank and the heated low-temperature molten salt can ensure that the temperature of the molten salt entering the heater remains basically stable. At the same time, in conjunction with the second high-temperature storage tank, the speed and temperature of the molten salt entering the heater can be increased. In this way, under the premise of stable heater power, the molten salt temperature at the outlet of the heater can be ensured to meet the standard, which has the advantages of convenient control and the molten salt meeting the use requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the drawings required for use in the embodiments or related technical descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 A structural diagram of the present invention; Figure 2 Another structural diagram of the present invention; Figure 3 This is another structural diagram of the present invention. DETAILED DESCRIPTION

[0020] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0021] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0022] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0023] In current technology, the power grid adjusts electricity prices according to the amount of electricity consumption. Within a day, there is a multiple difference between the electricity price during peak electricity consumption and the electricity price during low electricity consumption. For enterprises, the blast furnace gas produced by coal coking can be used for steelmaking and other projects, and the excess production can be used for power generation. The blast furnace gas production is stable, which does not match the peak and valley of electricity prices. In other words, for enterprises, the benefits of power generation during the trough of electricity prices are far lower than power generation during the peak of electricity prices.

[0024] To this end, a molten salt energy storage system is installed in parallel with the power generation system using blast furnace gas. The chemical energy of the blast furnace gas is converted into thermal energy during the period of low electricity prices and stored in molten salt. When the electricity price peaks, the molten salt that stores thermal energy releases energy and generates electricity, thereby improving enterprise efficiency.

[0025] In addition, the company also found that using green electricity to heat molten salt only requires transforming the green electricity to a safe range, without the need for complex inversion, rectification and other processes. On the one hand, it can reduce the occupancy of substations, and on the other hand, it can reduce the waste of green electricity in the inversion and rectification process. In other words, the molten salt energy storage system can effectively utilize green electricity and has high safety.

[0026] However, the heating power of green electricity is unstable, and the molten salt energy storage system using green electricity may have a situation where the temperature of the molten salt after heating does not meet the standard or exceeds the standard. In particular, when the molten salt energy storage system using green electricity is combined with the molten salt energy storage system using blast furnace gas as energy, it may also interfere with the normal operation of the molten salt energy storage system using blast furnace gas as energy.

[0027] Based on this, on the one hand, Figure 1 As shown, some embodiments of the present invention propose a molten salt heat storage system coupled with green electricity heating. The molten salt heat storage system coupled with green electricity heating comprises: a first low-temperature storage tank 1, an electric heating module 2, a first high-temperature storage tank 3 and a heater 4. Among them, the first low-temperature storage tank 1 stores low-temperature molten salt. The power supply end of the electric heating module 2 is electrically connected to the green electricity supply end, and the pipeline input end of the electric heating module 2 is connected to the first low-temperature storage tank 1. The first high-temperature storage tank 3 stores high-temperature molten salt. The input end of the mixer 9 is connected to the pipeline output end of the electric heating module 2 and the output end of the first high-temperature storage tank 3. The mixer 9 mixes the molten salt from the electric heating module 2 and the molten salt from the first high-temperature storage tank 3 evenly, and makes the mixed molten salt be a first temperature. The heater 4 is connected to the mixer 9, and the heater 4 is configured to receive the mixed molten salt from the mixer 9 and heat the mixed molten salt to a second temperature.

[0028] In some examples, low-temperature molten salt is stored in the first low-temperature storage tank 1, and the temperature of the low-temperature molten salt is greater than 150°C. For example, the temperature of the low-temperature molten salt can be 280°C~290°C. The first low-temperature storage tank 1 is connected to the electric heating module 2, and the electric heating module 2 can use an electric heating molten salt furnace, or use other heating structures. The specific structural examples of the electric heating module 2 are described in the following content.

[0029] A low-temperature molten salt pump is arranged between the first low-temperature storage tank 1 and the electric heating module 2, which can inject the low-temperature molten salt in the first low-temperature storage tank 1 into the electric heating module 2 at a constant speed, and then inject it into the mixer 9 together with the high-temperature molten salt in the first high-temperature storage tank 3 for mixing after heating.

[0030] Among them, the high-temperature molten salt can be 400~580℃, for example, the high-temperature molten salt problem can be 540℃, the mixer 9 can be a static mixer, a pipeline mixer, etc. At present, it can be understood that the material of the mixer 9 should be able to withstand a high temperature of 580℃.

[0031] According to the molten salt temperature and output speed output by the electric heating module 2, and the temperature of the molten salt that needs to be added to the heater 4, the output speed of the high-temperature molten salt in the first high-temperature storage tank 3 can be controlled, so that the first temperature of the molten salt after the molten salt output by the electric heating module 2 and the high-temperature molten salt are mixed is within the acceptable range of the heater 4. For example, the first temperature can be greater than 300°C and less than 500°C, and the fluctuation range of the first temperature is less than 20°C.

[0032] The heater 4 receives the molten salt from the mixer 9 and heats it. In the present application, the heater 4 can be a blast furnace gas molten salt furnace, which heats the molten salt from the mixer 9 from a first temperature to a second temperature, which can be 540°C. The molten salt reaching 540°C is stored and used to generate electricity during peak power consumption of the power grid.

[0033] Preferably, if Figure 2 As shown, the molten salt heat storage system coupled with green electricity heating further includes a second high-temperature storage tank 5. The second high-temperature storage tank 5 is disposed between the mixer 9 and the heater 4, and the second high-temperature storage tank 5 is configured to store the evenly mixed molten salt and regulate the speed of the evenly mixed molten salt injected into the heater 4 to be stable.

[0034] Preferably, if Figure 3 As shown, the molten salt heat storage system coupled with green electricity heating further includes a third high temperature storage tank 6. The third high temperature storage tank 6 is connected to the outlet end of the heater 4, and the outlet end of the heater 4 is also connected to the first high temperature storage tank 3.

[0035] Preferably, the molten salt heat storage system coupled with green electricity heating further includes: a first temperature sensor, a second temperature sensor and a variable frequency molten salt pump. The first temperature sensor is arranged at the outlet end of the electric heating module 2, and the first temperature sensor is configured to monitor the real-time temperature of the outlet end of the electric heating module 2. The second temperature sensor is arranged at the outlet end of the mixer 9, and the second temperature sensor is configured to monitor the real-time temperature of the outlet end of the mixer 9. The variable frequency molten salt pump is arranged on the pipeline between the first high temperature storage tank 3 and the mixer 9, and the variable frequency molten salt pump is configured to control the injection amount of the molten salt in the first high temperature storage tank 3 into the mixer 9 according to the data collected by the first temperature sensor.

[0036] Preferably, the heater 4 includes a gas-fired molten salt furnace. The molten salt heat storage system coupled with green electricity heating also includes a first air preheater. The first air preheater is connected to the exhaust port of the gas-fired molten salt furnace, and the first air preheater is arranged between the first low-temperature storage tank 1 and the electric heating module 2, and the first air preheater is configured to preheat the low-temperature molten salt transported from the first low-temperature storage tank 1 to the electric heating module 2.

[0037] Preferably, the molten salt heat storage system coupled with green electricity heating further includes: a second low-temperature storage tank 7 and a second air preheater 8. The second low-temperature storage tank 7 stores low-temperature molten salt, and the outlet end of the second low-temperature storage tank 7 is connected to the inlet end of the mixer 9. A second air preheater 8 is provided between the second low-temperature storage tank 7 and the mixer 9, and the second air preheater 8 is configured to preheat the low-temperature molten salt transported from the second low-temperature storage tank 7 to the mixer 9.

[0038] On the other hand, some embodiments of the present invention also provide a molten salt power generation system coupled with green electricity heating. The molten salt power generation system coupled with green electricity heating comprises: a molten salt heat storage system coupled with green electricity heating, a steam generation system and a steam turbine as described in the above one aspect. The inlet end of the molten salt pipeline of the steam generation system is connected to the second high-temperature storage tank 5 of the molten salt heat storage system coupled with green electricity heating, and the outlet end of the molten salt pipeline of the steam generation system is connected to the first low-temperature storage tank 1 and the second low-temperature storage tank 7. The steam turbine is connected to the steam generation system.

[0039] On the other hand, some embodiments of the present invention further provide a molten salt heat storage method coupled with green electricity heating, which is applicable to the molten salt heat storage system coupled with green electricity heating described in the above aspect.

[0040] The molten salt heat storage method coupled with green electricity heating comprises: S1. After transforming the green electricity to a safe voltage range, a fixed amount of low-temperature molten salt is heated within a unit time period to obtain electrically heated molten salt.

[0041] S2. According to the temperature of the electrically heated molten salt and the temperature of the first high-temperature molten salt, appropriate amounts of the first high-temperature molten salt and the electrically heated molten salt are mixed to obtain a mixed molten salt, wherein the mixed molten salt maintains a first temperature.

[0042] S3. Continue to heat the mixed molten salt to obtain high-temperature molten salt and store it.

[0043] In the description of this specification, specific features, structures, materials or characteristics may be combined in an appropriate manner in any one or more embodiments or examples.

[0044] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A molten salt heat storage system coupled with green electricity heating, characterized in that: include: a first cryogenic storage tank, wherein the first cryogenic storage tank stores cryogenic molten salt; An electric heating module, wherein a power supply end of the electric heating module is electrically connected to a green electricity supply end, and a pipeline input end of the electric heating module is in communication with the first low-temperature storage tank; a first high-temperature storage tank, wherein high-temperature molten salt is stored in the first high-temperature storage tank; A mixer, wherein the input end of the mixer is connected to the pipeline output end of the electric heating module and the output end of the first high-temperature storage tank, and the mixer mixes the molten salt from the electric heating module and the molten salt from the first high-temperature storage tank evenly, and makes the mixed molten salt have a first temperature; A heater is communicated with the mixer, and is configured to receive the molten salt after being mixed evenly in the mixer, and heat the molten salt after being mixed evenly to a second temperature.

2. The molten salt heat storage system coupled with green electricity heating according to claim 1 is characterized in that: The molten salt heat storage system coupled with green electricity heating also includes a second high-temperature storage tank; The second high-temperature storage tank is disposed between the mixer and the heater, and is configured to store the uniformly mixed molten salt and regulate the injection rate of the uniformly mixed molten salt into the heater to stabilize.

3. The molten salt heat storage system coupled with green electricity heating according to claim 1 is characterized in that: The molten salt heat storage system coupled with green electricity heating also includes a third high-temperature storage tank; The third high-temperature storage tank is in communication with an outlet end of the heater, and the outlet end of the heater is also in communication with the first high-temperature storage tank.

4. The molten salt heat storage system coupled with green electricity heating according to claim 1 is characterized in that: The molten salt heat storage system coupled with green electricity heating also includes: a first temperature sensor, the first temperature sensor being disposed at an outlet end of the electric heating module, and the first temperature sensor being configured to monitor a real-time temperature of the outlet end of the electric heating module; a second temperature sensor, the second temperature sensor being disposed at an outlet end of the mixer, the second temperature sensor cup being configured to monitor a real-time temperature of the outlet end of the mixer; A variable frequency molten salt pump is arranged on the pipeline between the first high temperature storage tank and the mixer, and the variable frequency molten salt pump is configured to control the injection amount of the molten salt in the first high temperature storage tank into the mixer according to the data collected by the first temperature sensor.

5. The molten salt heat storage system coupled with green electricity heating according to claim 1 is characterized in that: The heater comprises a gas-fired molten salt furnace; The molten salt heat storage system coupled with green electricity heating also includes a first air preheater; The first air preheater is connected to the exhaust port of the gas molten salt furnace, and is arranged between the first low-temperature storage tank and the electric heating module. The first air preheater is configured to preheat the low-temperature molten salt transported from the first low-temperature storage tank to the electric heating module.

6. The molten salt heat storage system coupled with green electricity heating according to claim 1 is characterized in that: The molten salt heat storage system coupled with green electricity heating also includes: a second cryogenic storage tank, wherein the second cryogenic storage tank stores low-temperature molten salt, and an outlet end of the second cryogenic storage tank is connected to an inlet end of the mixer; A second air preheater is provided between the second low-temperature storage tank and the mixer, and the second air preheater is configured to preheat the low-temperature molten salt transported from the second low-temperature storage tank to the mixer.

7. A molten salt power generation system coupled with green electricity heating, characterized in that: The molten salt power generation system coupled with green electricity heating comprises: A molten salt heat storage system coupled with green electricity heating as described in any one of claims 1 to 6 above; A steam generation system, wherein the inlet end of the molten salt pipeline of the steam generation system is connected to the second high-temperature storage tank of the molten salt heat storage system coupled with green electricity heating, and the outlet end of the molten salt pipeline of the steam generation system is connected to the first low-temperature storage tank and the second low-temperature storage tank; A steam turbine is in communication with the steam generating system.

8. A molten salt heat storage method coupled with green electricity heating, characterized in that: The molten salt heat storage system coupled with green electricity heating according to any one of claims 1 to 6 above, wherein the molten salt heat storage method coupled with green electricity heating comprises: After the green electricity is transformed into a safe voltage range, a certain amount of low-temperature molten salt is heated within a unit time period to obtain electrically heated molten salt; According to the temperature of the electrically heated molten salt and the temperature of the first high-temperature molten salt, a suitable amount of the first high-temperature molten salt and the electrically heated molten salt are mixed to obtain a mixed molten salt, wherein the mixed molten salt maintains a first temperature; The mixed molten salt is continuously heated to obtain high-temperature molten salt and stored.

9. The molten salt heat storage method coupled with green electricity heating according to claim 8, characterized in that: The molten salt heat storage system coupled with green electricity heating also includes a second high-temperature storage tank; The method of continuing to heat the mixed molten salt to obtain high-temperature molten salt and storing it: storing the mixed molten salt in the second high-temperature storage tank; Extracting mixed molten salt from the second high-temperature storage tank at a stable rate; The extracted mixed molten salt is heated to obtain high-temperature molten salt and stored.

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