A radiative waste heat recovery and utilization system based on phase change thermal storage and its operation method

Abstract

This invention discloses a radiative waste heat recovery and utilization system based on phase change thermal energy storage and its operation method. The radiative waste heat recovery and utilization system includes: a water tank; a radiative heat collection box, the outer wall of which is coated with a radiative heat absorption coating; heat exchange tubes installed inside the radiative heat collection box, which is filled with phase change energy storage material, and the phase change energy storage material covers the heat exchange tubes; a steam turbine connected to the heat exchange tubes, and connected to the water tank via a cooling tower; a heat exchanger, the inlet of the first heat exchange channel of the heat exchanger connected to the outlet of the heat exchange tubes, and the outlet of the first heat exchange channel of the heat exchanger connected to the first inlet of the water tank; and a second heat exchange channel of the heat exchanger for introducing the working fluid to be exchanged. The technical solution provided by this invention has the advantages of high heat storage and release efficiency and diverse utilization methods, and can realize the efficient recovery and utilization of radiative waste heat in industrial production sites.

Description

Technical Field

[0001] This invention belongs to the field of radiation waste heat recovery and utilization technology, and specifically relates to a radiation waste heat recovery and utilization system based on phase change thermal storage and its operation method. Background Technology

[0002] Energy utilization has been a constant throughout human societal development. From coal replacing firewood to oil replacing coal, energy efficiency has consistently increased. Currently, in the process of multi-energy conversion, various energy forms are being reused, leading to continuous improvements in energy efficiency and a significant positive impact on economic and social development. On the other hand, with increasing public awareness of environmental issues such as smog, developing a green economy has become a global focus. Therefore, the reuse of industrial waste heat resources is an inevitable trend.

[0003] In recent years, steel mills, aluminum plants, glass factories, forging plants, and other factories have generated a large amount of high-temperature radiant waste heat during production and transportation, which has not been effectively utilized. This has caused certain heat radiation to production workers and affected their health. For example, in steel mills, during the transfer and transportation of high-temperature iron blocks after casting, a large amount of radiant waste heat is lost into the air, and the heat is not effectively utilized. In summer, the temperature in the workers' workplaces is also high, causing discomfort to the workers.

[0004] The existing methods for handling the aforementioned waste heat from radiation involve rapid cooling (e.g., water spraying, air cooling, etc.). However, these rapid cooling methods waste resources and can negatively impact the mechanical properties of steel components. Therefore, how to efficiently collect, store, and utilize waste heat from radiation is a pressing technical problem that needs to be solved. Summary of the Invention

[0005] The purpose of this invention is to provide a radiative waste heat recovery and utilization system based on phase change thermal energy storage and its operation method, in order to solve one or more of the aforementioned technical problems. The radiative waste heat recovery and utilization system based on phase change thermal energy storage provided by this invention has the advantages of high heat storage and release efficiency and diverse utilization methods, enabling efficient recovery and utilization of radiative waste heat in industrial production sites.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] This invention provides a radiative waste heat recovery and utilization system based on phase change thermal storage, comprising:

[0008] Water tank;

[0009] A radiant heat collection box is provided with a radiant heat absorption coating on the outer wall of the box to absorb the residual radiant heat from a high-temperature radiant body; a heat exchange tube is provided inside the radiant heat collection box, and a phase change energy storage material is filled inside the radiant heat collection box, with the phase change energy storage material covering the heat exchange tube; wherein, the outlet of the water tank is connected to the inlet of the heat exchange tube via a water pump.

[0010] The turbine has its inlet connected to the outlet of the heat exchange tube via a fifth valve, and its outlet connected to the first inlet of the water tank via a cooling tower.

[0011] The heat exchanger has its inlet of the first heat exchange channel connected to the outlet of the heat exchange tube via a sixth valve, and its outlet connected to the first inlet of the water tank; the second heat exchange channel of the heat exchanger is used to introduce the working fluid to be exchanged.

[0012] A further improvement of the present invention is that the radiant heat collection box has a semi-cylindrical wall or a semi-elliptical wall, with an insulating coating on the outer side wall and a radiant heat absorbing coating on the inner side wall.

[0013] A further improvement of the present invention is that the radiative heat-absorbing coating is parabolic in shape.

[0014] A further improvement of the present invention is that the radiative heat absorption coating is a black nickel coating, a black chromium coating, an aluminum anodized coating, or a CuO conversion coating.

[0015] A further improvement of the present invention is that a filter is also provided on the connecting pipe between the water tank and the water pump.

[0016] A further improvement of the present invention is that the connecting pipe between the water pump and the heat exchange tube is connected to the second water inlet of the water tank.

[0017] A further improvement of the present invention is that a check valve, a fourth valve, and a damping buffer are sequentially arranged along the water flow direction on the connecting pipe between the water pump and the heat exchange tube.

[0018] A further improvement of the present invention is that a thermometer and a pressure gauge are also provided on the connecting pipe between the water pump and the heat exchange tube.

[0019] A further improvement of the present invention is that the phase change energy storage material is a phase change molten salt.

[0020] The present invention provides an operation method for a radiative waste heat recovery and utilization system based on phase change thermal storage. When utilizing heat, the fifth valve is opened and the sixth valve is closed to generate electricity through a steam turbine; or, the sixth and seventh valves are opened and the fifth valve is closed to provide heating through a heat exchanger.

[0021] The used water enters the water tank for reuse.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] To address the technical problem of difficulty in recovering high-temperature waste heat, this invention specifically provides a radiative waste heat recovery and utilization system based on phase change thermal storage. It is equipped with a radiative heat collection box, combined with high-temperature phase change energy storage materials, which can recover and store the radiative heat of high-temperature radiators. It integrates steam turbines and heat exchangers for subsequent utilization of heat, and has the advantages of high heat storage and release efficiency and diverse utilization methods, enabling efficient recovery and utilization of radiative waste heat in industrial production sites. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art are briefly introduced below; obviously, the drawings described below are some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of a radiative waste heat recovery and utilization system based on phase change thermal storage provided in an embodiment of the present invention;

[0026] Figure 2 This is a schematic diagram of the use of the radiative waste heat recovery and utilization system based on phase change thermal storage in an embodiment of the present invention.

[0027] In the diagram, 1. First valve; 2. Phase change energy storage material; 3. Water tank; 4. Second valve; 5. Third valve; 6. Fan; 7. Cooling tower; 8. Filter; 9. Water pump; 10. Fourth valve; 11. High-temperature radiator; 12. Damping buffer; 13. Radiant heat collection box; 14. Heat exchange tube; 15. First temperature measuring point; 16. Fifth valve; 17. Steam turbine; 18. Heat exchanger; 19. Seventh valve; 20. Thermometer; 21. Check valve; 22. Pressure gauge; 23. Radiant heat absorbing coating; 24. Second temperature measuring point; 25. Sixth valve. Detailed Implementation

[0028] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0029] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0030] The present invention will now be described in further detail with reference to the accompanying drawings:

[0031] Please see Figure 1 The present invention provides a radiative waste heat recovery and utilization system based on phase change thermal storage, comprising:

[0032] Water tank 3 is provided with a drain outlet, and a second valve 4 is provided on the connecting pipe of the drain outlet; the water tank 3 is also provided with a water outlet, a first water inlet and a second water inlet; an external water supply pipe is connected to the first water inlet, and the external water supply pipe is provided with a first valve 1;

[0033] A radiant heat collection box 13 is provided with a radiant heat absorption coating 23 on its outer wall to absorb the residual radiant heat from the high-temperature radiator 11. A heat exchange tube 14 is installed inside the radiant heat collection box 13, and the box is filled with a phase change energy storage material 2, which covers the heat exchange tube 14. The outlet of the water tank 3 is connected to the inlet of the heat exchange tube 14 via a water pump 9. Specifically, preferably, the water tank 3 and the water pump 9 are connected... A filter 8 is also installed on the connecting pipe; a check valve 21, a fourth valve 10, and a damping buffer 12 are sequentially installed along the water flow direction on the connecting pipe between the water pump 9 and the heat exchange pipe 14. A thermometer 20 and a pressure gauge 22 are also installed on the connecting pipe; the check valve 21 and the fourth valve 10 are associated with the water pump 9, and their function is to prevent backflow and regulate the water flow rate. The amount of heat utilized is determined by the water flow rate; the damping buffer 12 is used for shock absorption and noise reduction, reducing the impact of water flow and protecting the pipe safety. The thermometer 20 and pressure gauge 22 after the water pump 9 measure the temperature and pressure of the water. The thermometer 20 displays the temperature of the cooling water to improve utilization, and the pressure gauge 22 measures the pressure to protect the pipeline. For example, measuring the water temperature and pressure after the water pump 9 helps determine if the entire system is working properly. For instance, the temperature after the water pump 9 and before the inlet water pipe should not exceed 30°C (this can vary depending on the working environment). The connecting pipe between the fourth valve 10 and the damping buffer 12 is connected to the second inlet of the water tank 3. A third valve 5 is installed at the second inlet, which allows for simple impurity removal through the filter 8 in this circuit when heat utilization is not required, thus protecting the pipeline. The outer wall of the radiant heat collection box 13 has a first temperature measuring point 15 and a second temperature measuring point 24 at positions 1 / 3 and 2 / 3, respectively. For example, the temperature measuring points are holes opened in the box body, and thermocouples or similar devices are used to measure the temperature of the internal heat storage material. One function is to measure the amount of stored heat at any time, and the other is to ensure a suitable temperature to protect the equipment.

[0034] Steam turbine 17, the inlet of which is connected to the outlet of heat exchange tube 14 via fifth valve 16, and the outlet of which is connected to the first inlet of water tank 3 via cooling tower 7; cooling tower 7 is equipped with fan 6;

[0035] The heat exchanger 18 has its first heat exchange channel inlet connected to the outlet of the heat exchange tube 14 via a sixth valve 25, and its first heat exchange channel outlet connected to the first inlet of the water tank 3; the second heat exchange channel of the heat exchanger 18 is used to introduce the working medium to be exchanged, and a seventh valve 19 is provided on the second heat exchange channel of the heat exchanger 18.

[0036] In a preferred embodiment of the present invention, the radiant heat collection box 13 has a semi-cylindrical or semi-elliptical wall, with an insulating coating on the outer wall and a high-temperature resistant radiation-absorbing material coating similar to a black body on the inner wall; the radiant heat-absorbing coating 23 of the radiant heat collection box 13 is parabolic; the inlet and outlet of the heat exchange tube 14 are both located on the outer wall of the radiant heat collection box 13.

[0037] In the embodiments of this invention, the connecting pipes can be either copper pipes or stainless steel pipes.

[0038] In this embodiment of the invention, the radiation heat absorption coating 23 of the radiation heat collection box 13 is a high-temperature resistant material similar to a blackbody; for example, the radiation heat absorption coating 23 is a black nickel coating, a black chromium coating, an aluminum anodized coating, or a CuO conversion coating.

[0039] In this embodiment of the invention, the phase change energy storage material 2 filled in the radiant heat collection box 13 is a phase change molten salt.

[0040] In the technical solution provided by the embodiments of the present invention, the wastewater fluid can be purified through the water tank 3 circulation water supply system, can enter from the outside through the first valve 1, can be recycled through the water circuit for user-end wastewater, and can be discharged through the second valve 4.

[0041] In summary, this invention utilizes the high-density heat absorption and release characteristics of phase change energy storage materials during phase change, and the principle that radiative heat absorption coatings can effectively absorb radiative heat to achieve the purpose of recovering and storing radiative waste heat. Furthermore, the stored heat can be utilized in different ways at any time, solving the problem of difficulty in recovering and utilizing high-temperature radiative waste heat. It can be widely used in high-temperature heat recovery in various industries and has strong applicability to users.

[0042] In this embodiment of the invention, the heat storage can be utilized in different ways through the fifth valve 16 and the sixth valve 25.

[0043] When utilizing heat, the fifth valve 16 is opened and the sixth valve 25 is closed, and power is generated through the steam turbine 17; the sixth valve 25 and the seventh valve 19 are opened and the fifth valve 16 is closed, and heating is provided through the heat exchanger 18; the utilized water can enter the water tank 3, be purified through the water supply system, and be reused.

[0044] The technical solution provided by this invention can be used for various industrial high-temperature objects, such as high-temperature steel after casting in a steel plant, and high-temperature waste heat recovery and utilization of glass or formed copper products after heat treatment. The specific working process includes: the radiant heat absorption coating on the radiant heat collection box absorbs the radiant heat from the high-temperature radiator, and the heat is transferred to the phase change energy storage material inside the cavity of the radiant heat collection box through heat conduction on the box wall. The heat is converted into the internal energy of the phase change energy storage material within the radiant heat collection box. When heat is needed, the first and fourth valves are opened, and the third valve is closed. A water pump transfers the low-temperature fluid in the water tank to the heat exchange tube. The low-temperature fluid in the heat exchange tube exchanges heat with the phase change energy storage material in the radiant heat collection box, and the internal energy of the phase change energy storage material is absorbed through heat conduction and converted into high-temperature fluid. When generating electricity, the fifth valve is opened, and the sixth valve is closed. The high-temperature fluid flows through the turbine to generate electricity. After power generation, the fluid enters the cooling tower for cooling and then enters the water tank for reuse. When providing heat, the sixth and seventh valves are opened, and the fifth valve is closed. The high-temperature fluid flows through the heat exchanger for heating. After heating, the fluid flows back into the water tank for reuse.

[0045] In summary, this invention discloses a high-temperature radiative waste heat recovery and utilization system based on phase change thermal storage. It collects and stores the radiative waste heat from high-temperature objects using radiative heat exchange. Heat exchange tubes are laid within the cavity of the radiative heat collection chamber, and energy is transferred to the heat exchanger using an intermediate heat exchange fluid such as water. Simultaneously, high-temperature phase change material is filled into the cavity of the radiative heat collection chamber. The phase change energy storage material absorbs and stores radiative heat and fully exchanges heat with the fluid inside the heat exchange tubes, improving energy utilization efficiency. The device of this invention can effectively recover high-temperature waste heat from factories, realizing the secondary utilization of high-temperature waste heat resources, and has significant advantages such as energy saving and industrial scalability.

[0046] 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 it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A radiative waste heat recovery and utilization system based on phase change thermal storage, characterized in that, include: Water tank (3); A radiant heat collection box (13) is used to absorb the residual radiant heat of a high-temperature radiant body. The radiant heat collection box (13) has a semi-cylindrical or semi-elliptical wall, with an insulating coating on the outer side and a radiant heat absorption coating (23) on the inner side. The radiant heat absorption coating (23) is parabolic. A heat exchange tube (14) is installed inside the radiant heat collection box (13). The radiant heat collection box (13) is filled with a phase change energy storage material (2), which covers the heat exchange tube (14). The outlet of the water tank (3) is connected to the inlet of the heat exchange tube (14) via a water pump (9). Steam turbine (17), the inlet of the steam turbine (17) is connected to the outlet of the heat exchange tube (14) via the fifth valve, and the outlet of the steam turbine (17) is connected to the first inlet of the water tank (3) via the cooling tower (7); The heat exchanger (18) has its first heat exchange channel inlet connected to the outlet of the heat exchange tube (14) via a sixth valve, and its first heat exchange channel outlet connected to the first inlet of the water tank (3); the second heat exchange channel of the heat exchanger (18) is used to introduce the working medium to be exchanged.

2. The radiative waste heat recovery and utilization system based on phase change thermal storage according to claim 1, characterized in that, The radiation heat absorption coating (23) is a black nickel coating, a black chromium coating, an aluminum anodized coating, or a CuO conversion coating.

3. The radiative waste heat recovery and utilization system based on phase change thermal storage according to claim 1, characterized in that, A filter (8) is also installed on the connecting pipe between the water tank (3) and the water pump (9).

4. A radiative waste heat recovery and utilization system based on phase change thermal storage according to claim 3, characterized in that, The connecting pipe between the water pump (9) and the heat exchange pipe (14) is connected to the second inlet of the water tank (3).

5. A radiative waste heat recovery and utilization system based on phase change thermal storage according to claim 1, characterized in that, A check valve (21), a fourth valve, and a damping buffer (12) are sequentially installed along the water flow direction on the connecting pipe between the water pump (9) and the heat exchange tube (14).

6. A radiative waste heat recovery and utilization system based on phase change thermal storage according to claim 1, characterized in that, A thermometer (20) and a pressure gauge (22) are also installed on the connecting pipe between the water pump (9) and the heat exchange tube (14).

7. A radiative waste heat recovery and utilization system based on phase change thermal storage according to claim 1, characterized in that, The phase change energy storage material (2) is a phase change molten salt.

8. An operating method for a radiative waste heat recovery and utilization system based on phase change thermal storage as described in claim 1, characterized in that, When utilizing heat, the fifth valve is opened and the sixth valve is closed to generate electricity through the steam turbine (17); or, the sixth and seventh valves are opened and the fifth valve is closed to provide heating through the heat exchanger (18). The used water enters the water tank (3) for reuse.

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