Absorption heat exchange system combined with fused salt energy storage technology

Abstract

The utility model provides an absorption heat exchange system combined with a fused salt energy storage technology. The absorption heat exchange system comprises a low-temperature fused salt tank, a heating device, a high-temperature fused salt tank and a heat exchange device, the low-temperature molten salt tank, the heating device, the high-temperature molten salt tank and the heat exchange device are connected to form a circulation loop; low-temperature molten salt in the low-temperature molten salt tank is heated by the heating device and then conveyed to the high-temperature molten salt tank; and high-temperature molten salt in the high-temperature molten salt tank serves as a driving heat source of the heat exchange device and is used for driving the heat exchange device to operate. Industrial waste heat and the like are stored as heat energy through the fused salt energy storage technology to serve as a high-temperature heat source to drive the heat exchange device to operate, the industrial waste heat and the like are fully recycled, meanwhile, energy consumption is reduced, pollution to the environment is reduced, and carbon neutralization is promoted.

Description

Technical Field

[0001] This utility model relates to the field of molten salt energy storage technology, and in particular to an absorption heat exchange system that combines molten salt energy storage technology. Background Technology

[0002] Molten salt is a melt formed by melting salts; it is a melt composed of metal cations and non-metal anions. It features a high boiling point, low viscosity, low vapor pressure, and high volumetric heat, making it an excellent heat transfer and storage medium. Molten salt energy storage technology is divided into energy storage and energy utilization stages. The energy storage stage uses molten salt energy storage materials as a medium to store solar thermal energy, low-temperature heat, industrial waste heat, low-grade waste heat, and off-peak electricity as thermal energy. The energy utilization stage releases the heat from the molten salt when heat is needed, maximizing the energy efficiency of the entire system.

[0003] In the field of industrial energy conservation, heat exchange devices (such as absorption heat pumps, steam-water heat exchangers, and indirect heat exchangers) are widely used. However, these devices typically require high-temperature heat sources, resulting in significant energy consumption. Therefore, it is essential to develop an absorption heat exchange system that incorporates molten salt energy storage technology.

[0004] In view of this, this utility model is proposed. Utility Model Content

[0005] The purpose of this invention is to provide an absorption heat exchange system that combines molten salt energy storage technology. This system can combine molten salt energy storage technology with absorption heat exchange, recovering and utilizing industrial waste heat while reducing energy consumption.

[0006] This utility model provides an absorption heat exchange system combining molten salt energy storage technology, comprising: a low-temperature molten salt tank, a heating device, a high-temperature molten salt tank, and a heat exchange device; the low-temperature molten salt tank, the heating device, the high-temperature molten salt tank, and the heat exchange device are connected to form a circulation loop; the low-temperature molten salt in the low-temperature molten salt tank is heated by the heating device and then transported to the high-temperature molten salt tank; the high-temperature molten salt in the high-temperature molten salt tank serves as the driving heat source for the heat exchange device, thereby driving the operation of the heat exchange device.

[0007] Preferably, the heat exchange device includes: an absorption heat pump; the low-temperature molten salt tank, the heating device, the high-temperature molten salt tank, and the absorption heat pump are connected to form a circulation loop; the high-temperature molten salt tank is connected to the inlet of the absorption heat pump, and the low-temperature molten salt tank is connected to the outlet of the absorption heat pump; the high-temperature molten salt in the high-temperature molten salt tank is used to drive the absorption heat pump.

[0008] Absorption heat pumps are widely used as a major device for waste heat recovery and utilization. This device requires a high-temperature heat source to drive it, that is, it uses a small amount of high-temperature heat source to recover and utilize the heat from a low-temperature heat source to generate a large amount of usable medium-temperature heat energy, which is mainly used in the heating field. In addition, it can use a small amount of high-temperature heat source to generate a large amount of usable low-temperature cooling energy for summer cooling.

[0009] In this invention, during the energy storage phase, molten salt energy storage technology is combined with industrial waste heat recovery. Industrial waste heat, such as medium- and low-temperature flue gas and hot water, present in industries like coal combustion, gas combustion, steel, and chemicals, can be used to heat the molten salt, thus transferring this waste heat to the molten salt. The industrial waste heat temperature needs to be sufficient to melt the molten salt. During the energy consumption phase, molten salt energy storage technology is combined with an absorption heat pump. The molten salt releases heat to water or heats water into steam. Water, steam, or molten salt are directly used as the driving heat source for the absorption heat pump, reducing the consumption of other high-temperature heat sources and meeting both heating and cooling needs.

[0010] An absorption heat pump consists of nine main components forming a closed loop: absorber, generator (regenerator), condenser, evaporator, expansion valve, solution pump, solution valve, and solution heat exchanger. This closed loop is filled with a working fluid. The basic characteristics of each component in an absorption heat pump are as follows:

[0011] Working fluid pair: Generally, this is a binary non-azeotropic mixture composed of a circulating working fluid and an absorbent. The circulating working fluid (refrigerant) has a low boiling point, while the absorbent has a high boiling point, and there should be a significant difference between their boiling points. This is necessary to ensure the separation of the two components. The circulating working fluid should have high solubility in the absorbent; correspondingly, the working fluid pair solution should have a strong absorption capacity for the circulating working fluid.

[0012] Generator: The working fluid in the generator is heated by a high-temperature heat source such as hot water, steam or fuel flame, so that the low-boiling-point circulating working fluid in the generator turns into steam, while the high-boiling-point absorbent remains in a liquid state.

[0013] Absorber: Utilizing the strong absorption capacity of the working fluid on the solution of the circulating working fluid, the circulating working fluid generated in the evaporator is drawn into the absorber.

[0014] Condenser: The circulating working fluid vapor from the generator is condensed into liquid in the condenser, releasing heat in the process.

[0015] Throttling valve: The circulating working fluid with higher pressure and temperature before the valve becomes a mixture of saturated gas and saturated liquid with lower pressure and temperature after passing through the throttling valve, which is wet steam.

[0016] Evaporator: Low-pressure, low-temperature circulating wet steam absorbs heat from a low-temperature heat source in the evaporator and becomes saturated gas.

[0017] Solution pump: It continuously delivers the working fluid in the absorber to the generator in a dilute solution, maintaining the solution volume in both the absorber and the generator.

[0018] Solution valve: Its function is to regulate the amount of solution flowing from the generator into the absorber.

[0019] Solution heat exchanger: It is a component that exchanges heat between the dilute solution flowing out of the absorber and the concentrated solution flowing out of the generator. It lowers the temperature of the dilute solution entering the absorber, thereby increasing the absorption capacity of the solution in the absorber; and raises the temperature of the dilute solution entering the generator, thereby saving the high-temperature heat energy consumption in the generator.

[0020] Absorption cycles primarily utilize the hygroscopic properties of lithium bromide solution and the low boiling point of water under vacuum conditions. Absorption units (refrigeration units, heat pumps, heat exchange units, etc.) based on absorption cycles mainly consist of four components: a generator, a condenser, an evaporator, and an absorber. The lithium bromide solution and refrigerant water circulate within these four components, completing various heat exchange processes. A detailed explanation follows:

[0021] Generator: A dilute lithium bromide solution is heated and concentrated by a high-temperature heat source within the generator, producing water vapor and a concentrated lithium bromide solution, while the temperature of the heat source decreases simultaneously. The water vapor enters the condenser, and the concentrated lithium bromide solution enters the absorber.

[0022] Condenser: The water vapor generated by the generator enters the condenser. Due to the lower temperature of the external circulating water, the water vapor condenses into refrigerant water, releasing heat to the external circulating water and raising its temperature. The refrigerant water then enters the evaporator.

[0023] Evaporator: After the refrigerant water enters the evaporator, its boiling point drops below the temperature of the external circulating water due to the pressure reduction. At this time, the refrigerant water evaporates and absorbs heat, and the generated water vapor enters the absorber; at the same time, the external circulating water releases heat and its temperature drops, producing a cooling effect.

[0024] Absorber: In the absorber, the concentrated solution absorbs water vapor and is diluted into a dilute solution. This process is exothermic, and the external circulating water is heated. The resulting dilute solution re-enters the generator for the next cycle.

[0025] The complete lithium bromide absorption heat pump cycle process is as follows: Figure 5 As shown. From an external perspective, the generator and evaporator lower the temperature of the external circulating water, while inside the condenser and absorber, the temperature of the external circulating water rises. If the external circulating water is used in the evaporator, a cooling effect can be produced; if the external circulating water is used in the condenser and absorber, a heating effect can be produced.

[0026] In addition, steam-water heat exchangers, partition heat exchangers, or other types of heat exchangers can be used to replace absorption heat pumps, but these other methods do not provide as much heat as the absorption heat pump in this invention.

[0027] Preferably, the heat exchange device includes: a heat exchanger and an absorption heat pump connected in sequence; the low-temperature molten salt tank, the heating device, the high-temperature molten salt tank and the heat exchanger are connected to form a circulation loop; the high-temperature molten salt tank is connected to the inlet of the heat exchanger, and the low-temperature molten salt tank is connected to the outlet of the heat exchanger; the high-temperature molten salt in the high-temperature molten salt tank is used to drive the absorption heat pump after heat exchange by the heat exchanger.

[0028] Preferably, the heat exchanger includes: a first heat exchanger and a second heat exchanger; the low-temperature molten salt tank, the heating device, the high-temperature molten salt tank, the first heat exchanger, and the second heat exchanger are connected to form a circulation loop; the high-temperature molten salt tank is connected to the inlet of the first heat exchanger, the outlet of the first heat exchanger is connected to the inlet of the second heat exchanger, and the low-temperature molten salt tank is connected to the outlet of the second heat exchanger; both the first heat exchanger and the second heat exchanger are connected to an absorption heat pump.

[0029] Preferably, the heating device is an electric heater.

[0030] Preferably, the heating device is a heat absorber.

[0031] Preferably, the absorption heat pump is connected to a heat user and / or a cold user.

[0032] Preferably, the absorption heat pump is connected to a low-temperature heat source delivery device.

[0033] Preferably, the absorption heat pump is a lithium bromide absorption heat pump.

[0034] Preferably, the heat exchanger is connected to a heat user.

[0035] Beneficial effects:

[0036] The technical solution of this utility model uses molten salt energy storage technology to store industrial waste heat as thermal energy, which is then used as a high-temperature heat source to drive the operation of the heat exchange device. This fully recovers and utilizes industrial waste heat while reducing energy consumption and environmental pollution, and is conducive to promoting carbon neutrality. Attached Figure Description

[0037] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0038] Figure 1 This is a schematic diagram of the absorption heat exchange system combining molten salt energy storage technology provided in Embodiment 1 of this utility model.

[0039] Figure 2 This is a schematic diagram of the absorption heat exchange system structure combining molten salt energy storage technology provided in Embodiment 2 of this utility model.

[0040] Figure 3 This is a schematic diagram of the absorption heat exchange system combining molten salt energy storage technology provided in Embodiment 3 of this utility model.

[0041] Figure 4 This is a schematic diagram of the absorption heat exchange system combining molten salt energy storage technology provided in Embodiment 4 of this utility model.

[0042] Figure 5 A flow chart of the lithium bromide absorption heat pump cycle provided by this utility model.

[0043] Explanation of reference numerals in the attached drawings: 1. Heat absorber; 2. High-temperature molten salt tank; 3. Low-temperature molten salt tank; 4. Absorption heat pump; 5. Heat user; 6. Cold user; 7. Low-temperature heat source delivery device; 8. Electric heater; 9. First heat exchanger; 10. Second heat exchanger. Detailed Implementation

[0044] The technical solution of this utility model will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0045] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0046] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified. Furthermore, the terms "installed," "connected," and "linked" should be interpreted broadly; for example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0047] Example 1

[0048] like Figure 1 As shown, this embodiment provides an absorption heat exchange system combining molten salt energy storage technology, including: a low-temperature molten salt tank 3, a heating device, a high-temperature molten salt tank 2, and a heat exchange device; the low-temperature molten salt tank 3, the heating device, the high-temperature molten salt tank 2, and the heat exchange device are connected to form a circulation loop; the low-temperature molten salt in the low-temperature molten salt tank 3 is heated by the heating device and then transported to the high-temperature molten salt tank 2; the high-temperature molten salt in the high-temperature molten salt tank 2 serves as the driving heat source for the heat exchange device, which is used to drive the operation of the heat exchange device.

[0049] In this embodiment, the heat exchange device includes: an absorption heat pump 4; a low-temperature molten salt tank 3, a heating device, a high-temperature molten salt tank 2, and the absorption heat pump 4 are connected to form a circulation loop; the high-temperature molten salt tank 2 is connected to the high-temperature heat source inlet of the absorption heat pump 4, and the low-temperature molten salt tank 3 is connected to the high-temperature heat source outlet of the absorption heat pump 4; the high-temperature molten salt in the high-temperature molten salt tank 2 is used to drive the absorption heat pump 4 to operate.

[0050] In this embodiment, the heating device is a heat absorber 1, which can absorb heat from high-grade heat sources such as converters and blast furnaces, or heat from nature such as solar energy and wind energy.

[0051] In this embodiment, the absorption heat pump 4 is connected to a heat user 5 and / or a cold user 6.

[0052] In this embodiment, the absorption heat pump 4 is connected to a low-temperature heat source delivery device 7.

[0053] In this embodiment, the absorption heat pump 4 is a lithium bromide absorption heat pump 4.

[0054] In this embodiment, the heat exchanger is connected to a heat user 5.

[0055] After absorbing industrial waste heat, the heat absorber 1 heats and melts the energy storage medium in the low-temperature molten salt tank 3, which then enters the high-temperature molten salt tank 2. When the absorption heat pump 4 needs to operate, the medium transfer system between the molten salt tank and the absorption heat pump 4 is activated to transfer the heat in the energy storage medium to the transport medium, which is not limited to molten salt, steam, or water. When the heated transport medium enters the absorption heat pump 4, it drives the operation of the absorption heat pump 4, realizing the existing function of the absorption heat pump 4: recovering industrial waste heat from the plant area and transferring the heat to heat users 5 and / or cold users 6, thus improving the quality of waste heat. After releasing heat in the absorption heat pump 4, the transport medium returns to the molten salt tank, awaiting the next heating process.

[0056] Example 2

[0057] like Figure 2 As shown, this embodiment provides an absorption heat exchange system that combines molten salt energy storage technology, which is basically the same as embodiment 1. The difference is that in this embodiment, the heating device is an electric heater 8, which can utilize off-peak electricity to reduce the economic cost of system operation.

[0058] Example 3

[0059] like Figure 3 As shown, this embodiment provides an absorption heat exchange system combining molten salt energy storage technology, including: a low-temperature molten salt tank 3, a heating device, a high-temperature molten salt tank 2, and a heat exchange device; the low-temperature molten salt tank 3, the heating device, the high-temperature molten salt tank 2, and the heat exchange device are connected to form a circulation loop; the low-temperature molten salt in the low-temperature molten salt tank 3 is heated by the heating device and then transported to the high-temperature molten salt tank 2; the high-temperature molten salt in the high-temperature molten salt tank 2 serves as the driving heat source for the heat exchange device, which is used to drive the operation of the heat exchange device.

[0060] In this embodiment, the heat exchange device includes: a heat exchanger and an absorption heat pump 4 connected in sequence; a low-temperature molten salt tank 3, a heating device, a high-temperature molten salt tank 2 and a heat exchanger are connected to form a circulation loop; the high-temperature molten salt tank 2 is connected to the inlet of the heat exchanger, and the low-temperature molten salt tank 3 is connected to the outlet of the heat exchanger; the high-temperature molten salt in the high-temperature molten salt tank 2 is used to drive the absorption heat pump 4 after heat exchange by the heat exchanger.

[0061] In this embodiment, the heat exchanger includes: a first heat exchanger 9 and a second heat exchanger 10; a low-temperature molten salt tank 3, a heating device, a high-temperature molten salt tank 2, the first heat exchanger 9 and the second heat exchanger 10 are connected to form a circulation loop; the high-temperature molten salt tank 2 is connected to the inlet of the first heat exchanger 9, the outlet of the first heat exchanger 9 is connected to the inlet of the second heat exchanger 10, and the low-temperature molten salt tank 3 is connected to the outlet of the second heat exchanger 10; both the first heat exchanger 9 and the second heat exchanger 10 are connected to the high-temperature heat source inlet and outlet of the absorption heat pump 4.

[0062] In this embodiment, the heating device is a heat absorber 1, which can absorb heat from high-grade heat sources such as converters and blast furnaces, or heat from nature such as solar energy and wind energy.

[0063] In this embodiment, the absorption heat pump 4 is connected to a heat user 5 and / or a cold user 6.

[0064] In this embodiment, the absorption heat pump 4 is connected to a low-temperature heat source delivery device 7.

[0065] In this embodiment, the absorption heat pump 4 is a lithium bromide absorption heat pump 4.

[0066] In this embodiment, the heat exchanger is connected to a heat user 5.

[0067] After absorbing industrial waste heat, the heat absorber 1 heats and melts the energy storage medium in the low-temperature molten salt tank 3, which then enters the high-temperature molten salt tank 2. The heat in the high-temperature molten salt tank 2 exchanges heat with the first heat exchanger 9 and the second heat exchanger 10. When the absorption heat pump 4 needs to operate, the medium transport system between the molten salt tank and the first and second heat exchangers 9 and 10 is activated to transfer the heat from the energy storage medium to the transport medium, which is not limited to molten salt, steam, or water. When the heated transport medium enters the first and second heat exchangers 9 and 10, heat exchange occurs, driving the absorption heat pump 4 to operate. This realizes the existing function of the absorption heat pump 4: recovering industrial waste heat from the plant area and transferring the heat to heat users 5 and / or cold users 6, thus improving the quality of waste heat. After the transport medium releases heat in the first and second heat exchangers 9 and 10, it returns to the molten salt tank to await the next heating process.

[0068] Example 4

[0069] like Figure 4 As shown, this embodiment provides an absorption heat exchange system that combines molten salt energy storage technology, which is basically the same as embodiment 3. The difference is that in this embodiment, the heating device is an electric heater 8, which can utilize off-peak electricity to reduce the economic cost of system operation.

[0070] This invention stores industrial waste heat and uses it to drive an absorption heat pump at appropriate times, replacing the high-temperature heat source. This reduces the consumption of high-temperature energy, recovers and utilizes waste heat, and achieves heating or cooling effects to meet user requirements. The system can operate year-round, recovering the investment in a short time, improving the system's economic efficiency, saving primary energy, fully utilizing industrial waste heat, reducing environmental pollution, and providing a new solution for addressing the energy crisis and promoting carbon neutrality.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model 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 or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. An absorption heat exchange system combining molten salt energy storage technology, characterized in that, include: The system comprises a low-temperature molten salt tank, a heating device, a high-temperature molten salt tank, and a heat exchange device; the low-temperature molten salt tank, heating device, high-temperature molten salt tank, and heat exchange device are connected to form a circulation loop; the low-temperature molten salt in the low-temperature molten salt tank is heated by the heating device and then transported to the high-temperature molten salt tank; the high-temperature molten salt in the high-temperature molten salt tank serves as the driving heat source for the heat exchange device, thereby driving its operation; the heat exchange device includes a heat exchanger and an absorption heat pump connected in sequence; the low-temperature molten salt tank, heating device, high-temperature molten salt tank, and heat exchanger are connected to form a circulation loop; the high-temperature molten salt tank is connected to the inlet of the heat exchanger, and the low-temperature molten salt tank is connected to the outlet of the heat exchanger; the high-temperature molten salt in the high-temperature molten salt tank, after heat exchange by the heat exchanger, drives the absorption heat pump; the heating device is a heat absorber; the absorption heat pump is connected to a low-temperature heat source delivery device.

2. The absorption heat exchange system combining molten salt energy storage technology according to claim 1, characterized in that, The heat exchanger includes: a first heat exchanger and a second heat exchanger; the low-temperature molten salt tank, the heating device, the high-temperature molten salt tank, the first heat exchanger, and the second heat exchanger are connected to form a circulation loop; the high-temperature molten salt tank is connected to the inlet of the first heat exchanger, the outlet of the first heat exchanger is connected to the inlet of the second heat exchanger, and the low-temperature molten salt tank is connected to the outlet of the second heat exchanger; both the first heat exchanger and the second heat exchanger are connected to an absorption heat pump.

3. The absorption heat exchange system combining molten salt energy storage technology according to claim 1, characterized in that, The absorption heat pump is connected to heat users and / or cold users.

4. The absorption heat exchange system combining molten salt energy storage technology according to claim 1, characterized in that, The absorption heat pump is a lithium bromide absorption heat pump.

5. The absorption heat exchange system combining molten salt energy storage technology according to claim 1, characterized in that, The heat exchanger is connected to a heat user.

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