Waste heat recovery system based on reflux condensation and waste heat recovery method

Abstract

The present invention provides a waste heat recovery system and a waste heat recovery method based on reflux condensation. The waste heat recovery system includes: a conversion mechanism configured to absorb the heat of a heating device to form an initial working fluid, convert the heat of the initial working fluid into mechanical energy, and output an intermediate working fluid; a first cooling mechanism configured to cool the intermediate working fluid through a cooling medium; a first conveying mechanism and a second conveying mechanism in parallel with each other, respectively receiving and conveying the intermediate working fluid conveyed by the first cooling mechanism; a second cooling mechanism receiving the intermediate working fluid conveyed by the first conveying mechanism and / or the second conveying mechanism and further cooling it. The first part of the cooled intermediate working fluid is conveyed to the conversion mechanism to form a circulation loop, and the second part of the cooled intermediate working fluid is refluxed and conveyed to the first conveying mechanism; a control mechanism adjusts the flow rate of the second part of the intermediate working fluid based on the temperature of the cooling medium, so that the second part of the intermediate working fluid condenses and mixes with the intermediate working fluid conveyed by the first cooling mechanism for conveying.

Description

Technical Field

[0001] At least one embodiment of the present invention relates to the technical field of waste heat recovery, and particularly to a waste heat recovery system and a waste heat recovery method based on reflux condensation. Background Art

[0002] In waste heat recovery systems such as nuclear submarines and ocean waste heat power generation, a liquid working medium absorbs waste heat to form a supercritical working medium. Subsequently, the energy of the supercritical working medium is converted into mechanical energy to complete waste heat recovery, and the working medium is further cooled to a liquid working medium by a cooling source of a cooling mechanism to achieve recycling.

[0003] However, when the temperature of the cooling source is relatively high, the cooling effect of the waste heat recovery system is poor, the subcooling is insufficient, the working medium cannot be fully condensed, and there will be a gas-liquid two-phase flow phenomenon, which seriously affects cavitation, reduces the working efficiency of the equipment in the waste heat recovery system and shortens the service life of the equipment. Summary of the Invention

[0004] In view of this, the present invention provides a waste heat recovery system and a waste heat recovery method based on reflux condensation, which are used to at least partially solve the above technical problems, improve the subcooling degree of the intermediate working medium in the waste heat recovery system, improve the cooling effect, weaken the gas-liquid two-phase flow phenomenon, and reduce the influence caused by cavitation.

[0005] The first aspect of the present invention provides a waste heat recovery system based on reflux condensation, which is applicable to heat recovery of a heating device, and includes: a conversion mechanism configured to absorb the heat of the heating device to form an initial working medium, convert the heat of the initial working medium into mechanical energy, and output an intermediate working medium; a first cooling mechanism configured to cool the intermediate working medium through a cooling medium; a first conveying mechanism and a second conveying mechanism in parallel with each other, respectively receiving and conveying the intermediate working medium conveyed by the first cooling mechanism; a second cooling mechanism receiving the intermediate working medium conveyed by the first conveying mechanism and / or the second conveying mechanism and further cooling it, and conveying the first part of the cooled intermediate working medium to the conversion mechanism to form a circulation loop, and conveying the second part of the cooled intermediate working medium back to the first conveying mechanism; and a control mechanism for adjusting the flow rate of the second part of the intermediate working medium conveyed back to the first conveying mechanism by the second cooling mechanism based on the temperature of the cooling medium, so that the second part of the intermediate working medium conveyed by the second cooling mechanism condenses and mixes with the intermediate working medium conveyed by the first cooling mechanism.

[0006] According to an embodiment of the present invention, the control mechanism is configured to close the second conveying mechanism when the temperature of the cooling medium is greater than a preset temperature, and adjust the flow rate of the intermediate working medium conveyed by the first conveying mechanism, so that the first part of the intermediate working medium conveyed by the second cooling mechanism is cooled to a liquid state; when the temperature of the cooling medium is less than or equal to the preset temperature, adjust the flow rates of the intermediate working media conveyed by the first conveying mechanism and the second conveying mechanism, so that the first part of the intermediate working medium conveyed by the second cooling mechanism is cooled to a liquid state.

[0007] According to an embodiment of the present invention, the waste heat recovery system based on reflux condensation further includes: a storage mechanism, disposed upstream of the second cooling mechanism, configured to receive the intermediate working medium conveyed by the first conveying mechanism and / or the second conveying mechanism, and perform gas-liquid separation to form a gaseous intermediate working medium and a liquid intermediate working medium, so as to convey the liquid intermediate working medium to the second cooling mechanism; and a driving mechanism, in response to the control mechanism, receiving the gaseous intermediate working medium conveyed by the storage mechanism and pressurizing and conveying it to the first cooling mechanism for further cooling.

[0008] According to an embodiment of the present invention, the second cooling mechanism includes: a heat exchange assembly, including a first conveying pipe and a second conveying pipe for receiving the liquid intermediate working medium conveyed by the storage mechanism; and a first throttle valve, disposed at the inlet end of the second conveying pipe to throttle and cool down the liquid intermediate working medium conveyed by the second conveying pipe, so as to cool the liquid intermediate working medium conveyed by the first conveying pipe; wherein, the liquid intermediate working medium in the first conveying pipe is conveyed to the conversion mechanism, and the liquid intermediate working medium at the outlet end of the second conveying pipe is conveyed to the first conveying mechanism.

[0009] According to an embodiment of the present invention, the conversion mechanism includes: a first heat exchange mechanism, configured to absorb the heat of the heating device to form an initial working medium; and an expander, receiving the initial working medium conveyed by the first heat exchange mechanism, converting the energy of the initial working medium into mechanical energy, and cooling the initial working medium to form the intermediate working medium.

[0010] According to an embodiment of the present invention, the first conveying mechanism includes: a conveying assembly, in response to the control mechanism, receiving and adjusting the flow rate of the intermediate working medium conveyed by the first cooling mechanism, and receiving the second part of the intermediate working medium conveyed by the second cooling mechanism, so as to mix and convey it to the storage mechanism; and a second throttle valve, parallel to the conveying assembly, in response to the control mechanism, receiving and adjusting the flow rate of the intermediate working medium of the first cooling mechanism flowing through the second throttle valve.

[0011] According to an embodiment of the present invention, the conveying assembly includes: an ejector configured to receive and utilize the intermediate working medium conveyed by the expander to eject the second part of the intermediate working medium conveyed by the second cooling mechanism; and a first regulating valve disposed between the first cooling mechanism and the ejector, and configured to regulate the flow rate of the intermediate working medium of the first cooling mechanism flowing through the ejector in response to the control mechanism.

[0012] According to an embodiment of the present invention, the second conveying mechanism includes a second regulating valve disposed between the first cooling mechanism and the storage mechanism, and configured to regulate the flow rate of the intermediate working medium conveyed by the first cooling mechanism flowing through the second regulating valve in response to the control mechanism.

[0013] According to an embodiment of the present invention, the waste heat recovery system based on reflux condensation further includes a second heat exchange mechanism, including: a first heat exchange tube communicated between the expander and the first cooling mechanism to receive the intermediate working medium conveyed by the expander; and a second heat exchange tube communicated between the second cooling mechanism and the first heat exchange mechanism to receive the first part of the intermediate working medium conveyed by the second cooling mechanism, and configured to absorb the heat of the intermediate working medium in the first heat exchange tube and then convey it to the first heat exchange mechanism.

[0014] A second aspect of the present invention provides a waste heat recovery method based on the waste heat recovery system based on reflux condensation as described above, which is applicable to the heat recovery of a heating device, including: using a conversion mechanism to absorb the energy of the heating device to form an initial working medium, so as to convert the heat of the initial working medium into mechanical energy and output an intermediate working medium; cooling the intermediate working medium through a cooling medium of a first cooling mechanism; regulating the flow rate of the intermediate working medium conveyed to a second cooling mechanism by a second conveying mechanism and / or a first conveying mechanism based on the temperature of the cooling medium; further cooling the intermediate working medium conveyed by the second conveying mechanism and / or the first conveying mechanism by the second cooling mechanism, conveying the cooled first part of the intermediate working medium to the conversion mechanism to form a circulation loop, and regulating the flow rate of the cooled second part of the intermediate working medium flowing back to the first conveying mechanism based on the temperature of the cooling medium.

[0015] According to the waste heat recovery system and method based on reflux condensation provided by the present invention, the conversion mechanism absorbs the heat of the heating device to form an initial working medium, and converts the heat of the initial working medium into mechanical energies such as rotational kinetic energy, linear kinetic energy, and elastic potential energy, and outputs an intermediate working medium with a reduced temperature, thereby realizing the recovery and utilization of the waste heat of the heating device. The first cooling mechanism cools the intermediate working medium output by the conversion mechanism through a cooling medium. The mutually parallel first conveying mechanism and the second conveying mechanism can receive and convey the intermediate working medium conveyed by the first cooling mechanism. The second cooling mechanism receives the intermediate working medium conveyed by the first conveying mechanism and / or the second conveying mechanism and cools it again. The first part of the cooled intermediate working medium is conveyed to the conversion mechanism to form a circulation loop, and the second part of the cooled intermediate working medium is conveyed back to the first conveying mechanism. The first part of the intermediate working medium absorbs the heat of the heating device in the conversion mechanism to form an initial working medium, thus realizing the cycle. Among them, the temperature of the second part of the intermediate working medium flowing through the second cooling mechanism is lower than the temperature of the intermediate working medium conveyed by the first cooling mechanism. In the circulation loop, the control mechanism adjusts the flow rate of the second part of the intermediate working medium conveyed back to the first conveying mechanism by the second cooling mechanism based on the temperature of the cooling medium of the first cooling mechanism, so that the second part of the intermediate working medium conveyed back by the second cooling mechanism condenses and mixes with the intermediate working medium conveyed by the first cooling mechanism for conveying, so as to improve the cooling capacity of the first conveying mechanism.

[0016] The beneficial effects of the present invention are that through the synergistic action of the first conveying mechanism and the second conveying mechanism, the flow rate of the second part of the intermediate working medium conveyed back to the first conveying mechanism by the second cooling mechanism is adjusted based on the temperature of the cooling medium, so as to improve the environmental adaptability of the waste heat recovery system, improve the cooling effect of the first conveying mechanism, and further increase the subcooling degree of the intermediate working medium in the waste heat recovery system based on reflux condensation, improve the cooling effect of the waste heat recovery system, weaken the gas-liquid two-phase flow phenomenon, and reduce the influence of cavitation. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Through the following description of the embodiments of the present invention with reference to the drawings, the above and other objects, features, and advantages of the present invention will become clearer. In the drawings:

[0018] Figure 1 Schematically shows the working principle diagram of the waste heat recovery system based on reflux condensation according to the embodiment of the present invention.

[0019] Figure 2 Schematically shows the flow chart of the waste heat recovery method according to the embodiment of the present invention.

[0020] REFERENCE SIGNS

[0021] 1. Conversion mechanism; 11. First heat exchange mechanism; 12. Expander; 2. First cooling mechanism; 3. First conveying mechanism; 31. Conveying assembly; 311. Injector; 312. First regulating valve; 32. Second throttle valve; 4. Second conveying mechanism; 41. Second regulating valve; 5. Second cooling mechanism; 51. Heat exchange assembly; 511. First conveying pipe; 512. Second conveying pipe; 52. First throttle valve; 6. Storage mechanism; 7. Driving mechanism; 8. Second heat exchange mechanism; 81. First heat exchange pipe; 82. Second heat exchange pipe; 9. Heating device; 10. Pump. Detailed implementation manners

[0022] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the following further describes the present invention in detail with reference to specific embodiments and the accompanying drawings.

[0023] The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. The terms "including", "comprising", etc. used herein indicate the presence of the described features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0024] All terms used herein, including technical and scientific terms, have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification, and should not be interpreted in an idealized or overly rigid manner.

[0025] In the case of using expressions such as "at least one of the second conveying mechanism, B, and C", generally, it should be interpreted according to the meaning commonly understood by those skilled in the art. For example, "a system having at least one of the second conveying mechanism, B, and C" should include, but not be limited to, a system having only the second conveying mechanism, only B, only C, having the second conveying mechanism and B, having the second conveying mechanism and C, having B and C, and / or having the second conveying mechanism, B, and C. In the case of using expressions such as "at least one of the second conveying mechanism, B, or C", generally, it should be interpreted according to the meaning commonly understood by those skilled in the art. For example, "a system having at least one of the second conveying mechanism, B, or C" should include, but not be limited to, a system having only the second conveying mechanism, only B, only C, having the second conveying mechanism and B, having the second conveying mechanism and C, having B and C, and / or having the second conveying mechanism, B, and C.

[0026] It should also be noted that the directional terms mentioned in the embodiments, such as "up", "down", "front", "back", "left", "right", etc., are only references to the directions in the accompanying drawings and are not used to limit the protection scope of the present invention. Throughout the accompanying drawings, the same elements are represented by the same or similar reference numerals. When it may cause confusion in the understanding of the present invention, the conventional structures or configurations will be omitted.

[0027] In the waste heat recovery system, the liquid working medium in the waste heat recovery system absorbs the waste heat of the heating device and forms a supercritical working medium. Subsequently, the energy of the supercritical working medium is converted into mechanical energy to complete the waste heat recovery, and the working medium is further cooled to a liquid working medium by the cooling source of the cooling mechanism to achieve recycling. Among them, the cooling source can be seawater, gaseous coolant, etc. However, when the temperature of the cooling source is relatively high, the cooling effect of the waste heat recovery system is not good, the subcooling is insufficient, the working medium cannot be fully condensed, and there will be a gas-liquid two-phase flow phenomenon, and the cavitation effect is serious, which reduces the working efficiency of the equipment in the waste heat recovery system and shortens the equipment life.

[0028] Figure 1 Schematically shows the working principle diagram of the waste heat recovery system according to an embodiment of the present invention.

[0029] A first aspect of the present invention provides a waste heat recovery system based on reflux condensation, which is applicable to the heat recovery of the heating device 9. As Figure 1 shown, the waste heat recovery system based on reflux condensation includes a conversion mechanism 1, a first cooling mechanism 2, a first conveying mechanism 3, a second conveying mechanism 4, a second cooling mechanism 5 and a control mechanism. The conversion mechanism 1 is configured to absorb the heat of the heating device 9 to form an initial working medium, convert the heat of the initial working medium into mechanical energy, and output an intermediate working medium. The first cooling mechanism 2 is configured to cool the intermediate working medium through a cooling medium. The first conveying mechanism 3 and the second conveying mechanism 4 are parallel to each other and respectively receive and convey the intermediate working medium conveyed by the first cooling mechanism 2. The second cooling mechanism 5 receives the intermediate working medium conveyed by the first conveying mechanism 3 and / or the second conveying mechanism 4 and further cools it. The first part of the cooled intermediate working medium is conveyed to the conversion mechanism 1 to form a circulation loop, and the second part of the cooled intermediate working medium is conveyed back to the first conveying mechanism 3. The control mechanism adjusts the flow rate of the second part of the intermediate working medium conveyed back to the first conveying mechanism 3 by the second cooling mechanism 5 based on the temperature of the cooling medium, so that the second part of the intermediate working medium conveyed by the second cooling mechanism 5 condenses and mixes with the intermediate working medium conveyed by the first cooling mechanism 2.

[0030] It should be noted that the heating device 9 can be a nuclear reactor pressure vessel or other nuclear energy devices, which generate heat during operation. The waste heat recovery system based on reflux condensation exchanges heat with the heating device 9, enabling the working fluid in the waste heat recovery system based on reflux condensation to absorb the heat of the heating device 9 and convert the heat into mechanical energy for recovery and utilization. At the same time, the working fluid in the waste heat recovery system based on reflux condensation forms a high-temperature working fluid after absorbing heat. The high-temperature working fluid is cooled to a low-temperature working fluid and then exchanges heat with the heating device 9 again to form a high-temperature working fluid, realizing the cycle. Among them, the working fluid in the waste heat recovery system based on reflux condensation can be carbon dioxide, helium, etc., which is specifically selected according to actual needs. In this embodiment, the working fluid is described by taking carbon dioxide as an example.

[0031] Specifically, the conversion mechanism 1 exchanges heat with the heating device 9 to absorb the heat of the heating device 9 and form an initial working fluid in a supercritical state. Subsequently, the energy of the initial working fluid is converted into mechanical energy such as rotational kinetic energy, linear kinetic energy, and elastic potential energy, and an intermediate working fluid with a reduced temperature is output, realizing the recovery and utilization of the waste heat of the heating device 9. The conversion mechanism 1 can be a heat exchange device and a device that uses energy to do work. The heat exchange device can be an absorber, which is not limited herein. The device that uses thermal energy to do work can be an expander, a turboexpander, a scroll expander, an internal combustion engine, etc., which is specifically limited according to actual needs.

[0032] Furthermore, the first cooling mechanism 2 cools the transported intermediate working fluid through a cooling medium to reduce the temperature of the intermediate working fluid. Among them, the cooling medium can be seawater, a gas coolant, etc., which is not limited herein.

[0033] The first conveying mechanism 3 and the second conveying mechanism 4 are parallel to each other and respectively receive and convey the intermediate working fluid conveyed by the first cooling mechanism 2, that is, the intermediate working fluids conveyed by the first conveying mechanism 3 and the second conveying mechanism 4 are in a split state and will not mix and affect each other. It should be noted that the first conveying mechanism 3 and the second conveying mechanism 4 include but are not limited to conveying pipes, regulating valves, and throttle valves. The flow rates of the intermediate working fluid conveyed by the first conveying mechanism 3 and the second conveying mechanism 4 can be adjusted.

[0034] The second cooling mechanism 5 receives the intermediate working medium conveyed by the first conveying mechanism 3 and / or the second conveying mechanism 4, and after re-cooling, forms a first part of the intermediate working medium in a liquid state and conveys it to the conversion mechanism 1 to form a circulation loop. The second part of the cooled intermediate working medium is conveyed back to the first conveying mechanism 3. The first part of the intermediate working medium absorbs the heat of the heating device 9 in the conversion mechanism 1 to form an initial working medium in a supercritical state, realizing the circulation. Among them, the temperature of the second part of the intermediate working medium cooled by the second cooling mechanism 5 is lower than the temperature of the intermediate working medium conveyed by the first cooling mechanism 2. In the waste heat recovery system based on reflux condensation, the control mechanism adjusts the flow rate of the second part of the intermediate working medium conveyed back to the first conveying mechanism 3 by the second cooling mechanism 5 based on the temperature of the cooling medium of the first cooling mechanism 2, so that the second part of the intermediate working medium conveyed back by the second cooling mechanism 5 condenses and mixes with the intermediate working medium conveyed by the first cooling mechanism 2 for conveying, so as to improve the cooling capacity of the first conveying mechanism 3.

[0035] According to an embodiment of the present invention, through the coordinated action of the first conveying mechanism 3 and the second conveying mechanism 4, the subcooling degree of the intermediate working medium in the waste heat recovery system based on reflux condensation is increased, that is, the flow rate of the second part of the intermediate working medium conveyed back to the first conveying mechanism 3 by the second cooling mechanism 5 is adjusted based on the temperature of the cooling medium, so that the second part of the intermediate working medium conveyed by the second cooling mechanism 5 condenses and mixes with the intermediate working medium conveyed by the first cooling mechanism 2 for conveying, improving the cooling effect, weakening the gas-liquid two-phase flow phenomenon, and reducing the influence of cavitation.

[0036] In an exemplary embodiment, a driving pump 10 is provided between the second cooling mechanism 5 and the conversion mechanism 1 to pump the intermediate working medium conveyed by the second cooling mechanism 5 into the conversion mechanism 1 to realize the circulation.

[0037] In an exemplary embodiment, the control mechanism is configured to close the second conveying mechanism 4 when the temperature of the cooling medium is greater than the preset temperature, and adjust the flow rate of the intermediate working medium conveyed by the first conveying mechanism 3 so that the first part of the intermediate working medium conveyed by the second cooling mechanism 5 is cooled to a liquid state. When the temperature of the cooling medium is less than or equal to the preset temperature, the flow rates of the intermediate working media conveyed by the first conveying mechanism 3 and the second conveying mechanism 4 are adjusted so that the first part of the intermediate working medium conveyed by the second cooling mechanism 5 is cooled to a liquid state.

[0038] It should be noted that when the temperature of the cooling medium is greater than the preset temperature, it indicates that the cooling capacity of the first cooling mechanism 2 is reduced. Therefore, there is a higher demand for the cooling capacity of other components in the waste heat recovery system based on reflux condensation except the first cooling mechanism 2 to cool the first part of the intermediate working medium transported by the second cooling mechanism 5 to the liquid state. Specifically, when the intermediate working medium is carbon dioxide, the saturation temperature of carbon dioxide refers to the temperature at which liquid carbon dioxide and carbon dioxide vapor reach dynamic equilibrium. When the temperature of carbon dioxide is approximately 2°C lower than the saturation temperature of carbon dioxide, carbon dioxide is in the liquid state. In this way, by cooling the intermediate working medium to the liquid state, the gas-liquid two-phase flow phenomenon is weakened, and the influence of cavitation is reduced.

[0039] Furthermore, the first conveying mechanism 3 receives the second part of the intermediate working medium transported by the second cooling mechanism 5, so that the second part of the intermediate working medium transported by the second cooling mechanism 5 is mixed and transported with the intermediate working medium transported by the first cooling mechanism 2. Since the second cooling mechanism 5 further cools the intermediate working medium, the temperature of the second part of the intermediate working medium transported by the second cooling mechanism 5 is lower than the temperature of the intermediate working medium transported by the first cooling mechanism 2. Therefore, the cooling capacity of the first conveying mechanism 3 is higher than that of the second conveying mechanism 4.

[0040] Specifically, the cooling medium can be seawater. The temperature of seawater will change under the influence of factors such as weather and region. The preset temperature is determined according to the type of the cooling medium. When the cooling medium is seawater, the intermediate working medium is carbon dioxide, and when the temperature of the seawater is greater than 28°C, it indicates that the cooling capacity of the first cooling mechanism 2 is insufficient. At this time, the second conveying mechanism 4 is closed, and the flow rate of the intermediate working medium transported by the first conveying mechanism 3 is adjusted so that the first part of the intermediate working medium transported by the second cooling mechanism 5 to the conversion mechanism 1 is cooled to the liquid state. Since the cooling capacity of the first conveying mechanism 3 is higher than that of the second conveying mechanism 4, in this way, the cooling capacity of the waste heat recovery system based on reflux condensation can be improved, ensuring that the intermediate working medium is cooled to the liquid state, weakening the gas-liquid two-phase flow phenomenon, and reducing the influence of cavitation.

[0041] In this way, based on the temperature of the cooling medium, the flow rates of the intermediate working medium transported by the first conveying mechanism 3 and the second conveying mechanism 4 are adjusted to solve the problem of insufficient subcooling when the temperature of the cooling medium is higher than the preset temperature, improve the environmental adaptability of the waste heat recovery system based on reflux condensation, and increase the subcooling degree of the intermediate working medium in the waste heat recovery system based on reflux condensation, improve the cooling effect, weaken the gas-liquid two-phase flow phenomenon, and reduce the influence of cavitation.

[0042] When the cooling medium is seawater, the intermediate working medium is carbon dioxide, and the temperature of the seawater is less than or equal to 28 °C, the cooling capacity of the first cooling mechanism 2 is characterized as being relatively high. At this time, the flow rates of the intermediate working medium conveyed by the first conveying mechanism 3 and the second conveying mechanism 4 are adjusted so that the first part of the intermediate working medium conveyed by the second cooling mechanism 5 to the conversion mechanism 1 is cooled to the liquid state. It should be noted that since the first conveying mechanism 3 receives the second part of the intermediate working medium conveyed by the second cooling mechanism 5, the second part of the intermediate working medium conveyed by the second cooling mechanism 5 is mixed and conveyed with the intermediate working medium conveyed by the first cooling mechanism 2. In this way, the energy consumption of the first conveying mechanism 3 is greater than that of the second conveying mechanism 4.

[0043] In this way, based on the temperature of the cooling medium, the flow rates of the intermediate working medium conveyed by the first conveying mechanism 3 and the second conveying mechanism 4 are adjusted to achieve the cooperative effect of the first conveying mechanism 3 and the second conveying mechanism 4, and the effect of reducing energy consumption is achieved.

[0044] According to an embodiment of the present invention, based on the temperature of the cooling medium, the flow rates of the intermediate working medium conveyed by the first conveying mechanism 3 and the second conveying mechanism 4 are adjusted so that the waste heat recovery system based on reflux condensation can operate stably in an environment where the temperature range of the cooling medium is 4 °C - 35 °C, improving the environmental adaptability of the waste heat recovery system based on reflux condensation. At the same time, through the cooperative effect of the first conveying mechanism 3 and the second conveying mechanism 4, the energy consumption is reduced, the subcooling degree of the intermediate working medium in the waste heat recovery system based on reflux condensation is increased, the cooling effect is improved, the gas-liquid two-phase flow phenomenon is weakened, and the influence of cavitation is reduced.

[0045] In an exemplary embodiment, as Figure 1 shown, the waste heat recovery system based on reflux condensation further includes a storage mechanism 6 and a driving mechanism 7. The storage mechanism 6 is disposed upstream of the second cooling mechanism 5 and is configured to receive the intermediate working medium conveyed by the first conveying mechanism 3 and / or the second conveying mechanism 4, and perform gas-liquid separation to form gaseous intermediate working medium and liquid intermediate working medium, so as to convey the liquid intermediate working medium to the second cooling mechanism 5. The driving mechanism 7 responds to the control mechanism, receives the gaseous intermediate working medium conveyed by the storage mechanism 6, and pressurizes and conveys it to the first cooling mechanism 2 for further cooling.

[0046] Specifically, the storage mechanism 6 is communicated with the first conveying mechanism 3 and the second conveying mechanism 4 through a conveying pipe to receive the intermediate working medium conveyed by the first conveying mechanism 3 and / or the second conveying mechanism 4. The storage mechanism 6 can be a gas-liquid separator, so as to perform gas-liquid separation on the intermediate working medium conveyed by the first conveying mechanism 3 and / or the second conveying mechanism 4 to form gaseous intermediate working medium and liquid intermediate working medium. In this way, the liquid intermediate working medium is located at the bottom of the storage mechanism 6, and the gaseous intermediate working medium is located at the top of the storage mechanism 6.

[0047] Specifically, the bottom of the storage mechanism 6 is connected to the second cooling mechanism 5 through a delivery pipe to deliver the liquid intermediate working medium to the second cooling mechanism 5. The top of the storage mechanism 6 is communicated with the driving mechanism 7 through a delivery pipe. The driving mechanism 7 can be a compressor. The driving mechanism 7 responds to the control mechanism, receives the gaseous intermediate working medium delivered by the storage mechanism 6, and pressurizes and delivers it to the first cooling mechanism 2 for further cooling. The control mechanism adjusts the rotation speed of the compressor based on the temperature of the first part of the intermediate working medium delivered by the second cooling mechanism 5, so that the first part of the intermediate working medium delivered by the second cooling mechanism 5 is in a liquid state. Under the cooling effect of the first cooling mechanism 2, part of the gaseous intermediate working medium is cooled into a liquid intermediate working medium, further reducing the gaseous intermediate working medium and further weakening the gas-liquid two-phase flow phenomenon.

[0048] According to an embodiment of the present invention, by providing the storage mechanism 6 and the driving mechanism 7, the intermediate working medium delivered by the first delivery mechanism 3 and / or the second delivery mechanism 4 can be separated into gas and liquid, and the gaseous intermediate working medium obtained by gas-liquid separation is pressurized and delivered to the first cooling mechanism 2 for cooling, so that part of the gaseous intermediate working medium is cooled into a liquid, further improving the cooling effect of the waste heat recovery system based on reflux condensation, further weakening the gas-liquid two-phase flow phenomenon, and reducing the influence of cavitation.

[0049] In an exemplary embodiment, as Figure 1 shown, the conversion mechanism 1 includes a first heat exchange mechanism 11 and an expander 12. The first heat exchange mechanism 11 is configured to absorb the heat of the heat supply device 9 to form an initial working medium. The expander 12 receives the initial working medium delivered by the first heat exchange mechanism 11, converts the energy of the initial working medium into mechanical energy, and cools the initial working medium to form an intermediate working medium.

[0050] Specifically, the first heat exchange mechanism 11 exchanges heat with the heat supply device 9, so that the first part of the intermediate working medium delivered by the second cooling mechanism 5 absorbs the heat of the heat supply device 9 to form a supercritical initial working medium. The supercritical initial working medium has the characteristics of high diffusivity, high density, and low viscosity, and the heat transfer efficiency is much higher than that of traditional working media such as water vapor.

[0051] Furthermore, the expander 12 receives the initial working medium and converts the energy of the initial working medium into mechanical energy such as rotational kinetic energy, linear kinetic energy, and elastic potential energy. At the same time, the initial working medium cools to form an intermediate working medium. Specifically, the expander 12 receives the initial working medium and converts it into rotational kinetic energy to do work. It can be understood that the expander 12 can be externally connected to a generator to generate electricity.

[0052] It should be noted that the kinetic energy of the intermediate working medium delivered by the expander 12 is relatively large.

[0053] According to an embodiment of the present invention, by providing the first heat exchange mechanism 11 and the expander 12, the heat of the heat supply device 9 can be absorbed, so that the first part of the intermediate working medium transported by the second cooling mechanism 5 forms an initial working medium in a supercritical state. In this way, the energy of the initial working medium can be converted into mechanical energy for work or power generation, recovering the heat of the heat supply device 9 and achieving energy recovery.

[0054] In an exemplary embodiment, as Figure 1 shown, the first conveying mechanism 3 includes a conveying component 31 and a second throttle valve 32. The conveying component 31 responds to the control mechanism to receive and adjust the flow rate of the intermediate working medium of the first cooling mechanism 2, and receives the second part of the intermediate working medium transported by the second cooling mechanism 5, and conveys the mixture to the storage mechanism 6. The second throttle valve 32 is parallel to the conveying component 31 and responds to the control mechanism to receive and adjust the flow rate of the intermediate working medium of the first cooling mechanism 2 flowing through the second throttle valve 32.

[0055] Specifically, the conveying component 31 responds to the control mechanism to receive and adjust the flow rate of the intermediate working medium transported by the first cooling mechanism 2, and receives the second part of the intermediate working medium transported by the second cooling mechanism 5. In this way, the conveying component 31 mixes the intermediate working medium transported by the first cooling mechanism 2 with the second part of the intermediate working medium transported by the second cooling mechanism 5 and conveys it to the storage mechanism 6.

[0056] Since the second cooling mechanism 5 further cools the intermediate working medium, the temperature of the second part of the intermediate working medium transported by the second cooling mechanism 5 is lower than that of the intermediate working medium transported by the first cooling mechanism 2. In this way, the second part of the intermediate working medium transported by the second cooling mechanism 5 flows back to the conveying component 31 to cool down the intermediate working medium of the first cooling mechanism 2 received by the conveying component 31, improving the cooling effect of the first conveying mechanism 3 and reducing energy consumption.

[0057] The first throttle valve 52 can be a throttle valve, which can not only receive and adjust the flow rate of the intermediate working medium of the first cooling mechanism flowing through the second throttle valve 32, but also cool down the intermediate working medium flowing through the second throttle valve 32 to improve the cooling effect of the first conveying mechanism 3.

[0058] Furthermore, the second throttle valve 32 is parallel to the conveying component 31 and responds to the control mechanism to receive and adjust the flow rate of the intermediate working medium of the first cooling mechanism 2 flowing through the second throttle valve 32. At the same time, the conveying component 31 responds to the control mechanism to receive and adjust the flow rate of the intermediate working medium transported by the first cooling mechanism 2. In this way, the flow rates of the intermediate working medium flowing through the conveying component 31 and the second throttle valve 32 are dynamically adjusted to adjust the cooling effect of the first conveying mechanism 3, reducing energy consumption while ensuring that the first part of the intermediate working medium transported by the second cooling mechanism 5 to the pump 10 is in a liquid state.

[0059] In an exemplary embodiment, as Figure 1As shown, the conveying assembly 31 includes an ejector 311 and a first regulating valve 312. The ejector 311 is configured to receive and utilize the intermediate working fluid conveyed by the expander 12 flowing through the first cooling mechanism 2 to eject the second part of the intermediate working fluid conveyed by the second cooling mechanism 5. The first regulating valve 312 is disposed between the first cooling mechanism 2 and the ejector 311, and regulates the flow rate of the intermediate working fluid of the first cooling mechanism 2 flowing through the ejector 311 in response to the control mechanism.

[0060] Specifically, since the kinetic energy of the intermediate working fluid conveyed by the expander 12 is large, the flow rate of the intermediate working fluid is high, and the flow rate of the intermediate working fluid conveyed by the first cooling mechanism 2 to the ejector 311 is also high. Thus, during the process of the ejector 311 receiving the intermediate working fluid flowing through the first cooling mechanism 2, the ejector 311 can utilize the intermediate working fluid with a high flow rate affected by the expander 12 to eject the second part of the intermediate working fluid conveyed by the second cooling mechanism 5, so as to recycle the kinetic energy of the intermediate working fluid conveyed by the expander 12, reduce throttling losses, improve the energy utilization effect, and reduce energy consumption. It should be noted that the entrainment ratio of the ejector 311 is dynamically adjusted according to real-time temperature and pressure data, and the entrainment ratio range does not exceed 1.0.

[0061] Furthermore, the first regulating valve 312 can be a regulating valve, a flow valve, etc., and is specifically selected according to actual needs. The first regulating valve 312 regulates the flow rate of the intermediate working fluid of the first cooling mechanism 2 flowing through the ejector 311 in response to the control mechanism. In this way, the flow rate flowing through the ejector 311 is regulated based on the temperature of the cooling medium to ensure that the first part of the intermediate working fluid conveyed by the second cooling mechanism 5 is cooled to a liquid state, improve the cooling effect, weaken the gas-liquid two-phase flow phenomenon, and reduce the influence of cavitation.

[0062] In an exemplary embodiment, as Figure 1 shown, the second conveying mechanism 4 includes a second regulating valve 41, which is disposed between the first cooling mechanism 2 and the storage mechanism 6, and regulates the flow rate of the intermediate working fluid conveyed by the first cooling mechanism 2 flowing through the second regulating valve 41 in response to the control mechanism.

[0063] Specifically, the second regulating valve 41 can be a bypass valve to shunt the intermediate working fluid conveyed by the first cooling mechanism 2 and regulate the flow rate of the intermediate working fluid conveyed by the first cooling mechanism 2 flowing through the second regulating valve 41. The intermediate working fluid flowing through the second regulating valve 41 is directly conveyed to the storage mechanism 6 without a cooling effect, and the energy consumption of the second conveying mechanism 4 is lower than that of the first conveying mechanism 3.

[0064] In such an embodiment, when the temperature of the cooling medium is greater than the preset temperature, the second conveying mechanism 4 is closed, and the first conveying mechanism 3 is used to convey the intermediate working medium and cool it down, ensuring that the first part of the intermediate working medium conveyed by the second cooling mechanism 5 is in a liquid state. When the temperature of the cooling medium is less than or equal to the preset temperature, the first conveying mechanism 3 and the second conveying mechanism 4 cooperate to adjust the flow rate of the intermediate working medium conveyed by the first conveying mechanism 3 and the second conveying mechanism 4, so as to reduce energy consumption when ensuring that the first part of the intermediate working medium conveyed by the second cooling mechanism 5 to the conversion mechanism 1 is cooled to a liquid state.

[0065] In one exemplary embodiment, as Figure 1 shown, the second cooling mechanism 5 includes a heat exchange assembly 51 and a first throttle valve 52. The heat exchange assembly 51 includes a first conveying pipe 511 and a second conveying pipe 512 for receiving and storing the liquid intermediate working medium conveyed by the receiving and storing mechanism 6. The first throttle valve 52 is provided at the inlet end of the second conveying pipe 512 to throttle and cool down the liquid intermediate working medium conveyed by the second conveying pipe 512, so as to cool the liquid intermediate working medium conveyed by the first conveying pipe 511. Among them, the liquid intermediate working medium in the first conveying pipe 511 is the first part of the intermediate working medium conveyed to the conversion mechanism 1, and the liquid intermediate working medium at the outlet end of the second conveying pipe 512 is the second part of the intermediate working medium that is refluxed and conveyed to the first conveying mechanism 3.

[0066] Specifically, the first throttle valve 52 may be a throttle valve. It should be noted that the first throttle valve 52 can adjust the flow rate of the intermediate working medium flowing through the first throttle valve 52. In addition, the temperature of the intermediate working medium flowing through the first throttle valve 52 will also decrease, and the first throttle valve 52 has the effect of cooling and reducing temperature.

[0067] Specifically, referring to Figure 1 shown, the inlet end of the first conveying pipe 511 is communicated with the storage mechanism 6 to receive the liquid intermediate working medium conveyed by the storage mechanism 6. The outlet end of the first conveying pipe 511 is communicated with the pump 10 to convey the first part of the intermediate working medium to the pump 10 and convey it to the first heat exchange mechanism 11 under the driving action of the pump 10. The first part of the intermediate working medium in the first conveying pipe 511 of the heat exchange assembly 51 flows from right to left.

[0068] The first throttle valve 52 is provided at the inlet end of the second conveying pipe 512. The inlet end of the second conveying pipe 512 is communicated with the storage mechanism 6 to receive the liquid intermediate working medium conveyed by the storage mechanism 6. The outlet end of the second conveying pipe 512 is communicated with the ejector 311 to reflux and convey the second part of the intermediate working medium that has been throttled and cooled by the first throttle valve 52 to the ejector 311. The second part of the intermediate working medium in the second conveying pipe 512 of the heat exchange assembly 51 flows from left to right.

[0069] In such an embodiment, the temperature of the second part of the intermediate working fluid in the second delivery pipe 512 decreases after flowing through the first throttle valve 52. Therefore, the temperature of the second part of the intermediate working fluid in the second delivery pipe 512 is lower than the temperature of the first part of the intermediate working fluid in the first delivery pipe 511. In this way, the first part of the intermediate working fluid conveyed by the first delivery pipe 511 exchanges heat with the second part of the intermediate working fluid conveyed by the second delivery pipe 512. Specifically, the second part of the intermediate working fluid conveyed by the second delivery pipe 512 cools the first part of the intermediate working fluid conveyed by the first delivery pipe 511 to achieve self-condensation, with low energy consumption, further improving the cooling effect of the waste heat recovery system based on reflux condensation, increasing the subcooling degree of the intermediate working fluid in the waste heat recovery system based on reflux condensation, weakening the gas-liquid two-phase flow phenomenon, and reducing the impact of cavitation.

[0070] In an exemplary embodiment, as Figure 1 shown, the waste heat recovery system based on reflux condensation further includes a second heat exchange mechanism 8. The second heat exchange mechanism 8 includes a first heat exchange pipe 81 and a second heat exchange pipe 82. The first heat exchange pipe 81 is connected between the expander 12 and the first cooling mechanism 2 to receive the intermediate working fluid conveyed by the expander 12. The second heat exchange pipe 82 is connected between the second cooling mechanism 5 and the first heat exchange mechanism 11, receives the first part of the intermediate working fluid conveyed by the second cooling mechanism 5, and conveys it to the first heat exchange mechanism 11 after absorbing the heat of the intermediate working fluid in the first heat exchange pipe 81.

[0071] Specifically, the intermediate working fluid conveyed by the expander 12 is conveyed to the first cooling mechanism 2 through the first heat exchange pipe 81. The first part of the intermediate working fluid conveyed by the second cooling mechanism 5 is conveyed to the first heat exchange mechanism 11 through the second heat exchange pipe 82. Since the temperature of the intermediate working fluid conveyed by the expander 12 is high and the temperature of the first part of the intermediate working fluid conveyed by the second cooling mechanism 5 is low. Therefore, the temperature of the intermediate working fluid in the first heat exchange pipe 81 is higher than the temperature of the intermediate working fluid in the second heat exchange pipe 82.

[0072] Specifically, referring to Figure 1 shown, the first heat exchange pipe 81 conveys the intermediate working fluid from right to left. The second heat exchange pipe 82 conveys the intermediate working fluid from left to right. In this way, the intermediate working fluid in the second heat exchange pipe 82 absorbs the heat of the intermediate working fluid in the first heat exchange pipe 81 and heats up, so that the intermediate working fluid conveyed to the first heat exchange mechanism 11 absorbs the heat of the heating device 9 to form an initial working fluid in a supercritical state. At the same time, the intermediate working fluid in the first heat exchange pipe 81 is cooled by the intermediate working fluid in the second heat exchange pipe 82 and its temperature decreases, so as to further improve the cooling effect on the intermediate working fluid, make the first part of the intermediate working fluid conveyed by the second cooling mechanism 5 to the pump 10 in a liquid state, increase the subcooling degree of the intermediate working fluid in the waste heat recovery system based on reflux condensation, weaken the gas-liquid two-phase flow phenomenon, and reduce the impact of cavitation.

[0073] The second aspect of the present invention provides a waste heat recovery method for a waste heat recovery system based on reflux condensation, which is applicable to the heat recovery of a heating device 9.

[0074] Figure 2 Schematically shows a flowchart of the waste heat recovery method according to an embodiment of the present invention. Referring to Figure 2 As shown, the waste heat recovery method includes operations S110 - S140.

[0075] Operation S110: Utilize the conversion mechanism 1 to absorb the heat of the heating device 9 to form an initial working medium, convert the energy of the initial working medium into mechanical energy, and output an intermediate working medium.

[0076] Operation S120: Cool the intermediate working medium with the cooling medium of the first cooling mechanism 2.

[0077] Operation S130: Based on the temperature of the cooling medium, adjust the flow rate of the intermediate working medium transported by the second transport mechanism 4 and / or the first transport mechanism 3 to the second cooling mechanism 5.

[0078] Operation S140: The second cooling mechanism 5 further cools the intermediate working medium transported from the second transport mechanism 4 and / or the first transport mechanism 3, transports the cooled first part of the intermediate working medium to the conversion mechanism 1 to form a circulation loop, and based on the temperature of the cooling medium, adjust the flow rate of the cooled second part of the intermediate working medium returned and transported to the first transport mechanism 3.

[0079] Specifically, in operation S110, the conversion mechanism 1 exchanges heat with the heating device 9 to absorb the heat of the heating device 9 to form an initial working medium in a supercritical state. Subsequently, convert the energy of the initial working medium into mechanical energy such as rotational kinetic energy, linear kinetic energy, elastic potential energy, etc., and output an intermediate working medium with a reduced temperature, realizing the recovery and utilization of the waste heat of the heating device 9. The conversion mechanism 1 can be a heat exchange device and a device that utilizes energy to do work.

[0080] In operation S120, the cooling medium of the first cooling mechanism 2 can be seawater, a gas coolant, etc. The first cooling mechanism 2 exchanges heat with the intermediate working medium to further cool the intermediate working medium.

[0081] In operation S130, the first transport mechanism 3 and the second transport mechanism 4 are parallel to each other and respectively receive and transport the intermediate working medium transported by the first cooling mechanism 2, that is, the intermediate working media transported by the first transport mechanism 3 and the second transport mechanism 4 are in a shunt state and will not mix and affect each other.

[0082] In operation S140, the second cooling mechanism 5 receives the intermediate working medium conveyed by the first conveying mechanism 3 and / or the second conveying mechanism 4, and after re-cooling, forms a first part of the intermediate working medium in a liquid state and conveys it to the conversion mechanism 1 to form a circulation loop. Then, the first part of the intermediate working medium absorbs the heat of the heat supply device 9 in the conversion mechanism 1 to form an initial working medium in a supercritical state, realizing the circulation.

[0083] The temperature of the second part of the intermediate working medium cooled by the second cooling mechanism 5 is lower than the temperature of the intermediate working medium conveyed by the first cooling mechanism 2. In the waste heat recovery system based on reflux condensation, the control mechanism adjusts the flow rate of the second part of the intermediate working medium refluxed and conveyed by the second cooling mechanism 5 to the first conveying mechanism 3 based on the temperature of the cooling medium of the first cooling mechanism 2, so that the second part of the intermediate working medium conveyed by the second cooling mechanism 5 condenses and mixes with the intermediate working medium conveyed by the first cooling mechanism 2 for conveying, so as to improve the cooling capacity of the first conveying mechanism 3.

[0084] According to the waste heat recovery system and waste heat recovery method based on reflux condensation provided in this embodiment, the conversion mechanism 1 absorbs the heat of the heat supply device 9 to form an initial working medium, and converts the heat of the initial working medium into mechanical energy such as rotational kinetic energy, linear kinetic energy, and elastic potential energy, and outputs the intermediate working medium with a reduced temperature, realizing the recovery and utilization of the waste heat of the heat supply device 9. The first cooling mechanism 2 cools the intermediate working medium output by the conversion mechanism 1 through a cooling medium. The mutually parallel first conveying mechanism 3 and the second conveying mechanism 4 can receive and convey the intermediate working medium conveyed by the first cooling mechanism 2. The second cooling mechanism 5 receives the intermediate working medium conveyed by the first conveying mechanism 3 and / or the second conveying mechanism 4, and cools it again. The cooled first part of the intermediate working medium is conveyed to the conversion mechanism 1 to form a circulation loop, and the cooled second part of the intermediate working medium is refluxed and conveyed to the first conveying mechanism 3. The first part of the intermediate working medium absorbs the heat of the heat supply device 9 in the conversion mechanism 1 to form an initial working medium, realizing the circulation. Among them, the temperature of the second part of the intermediate working medium cooled by the second cooling mechanism 5 is lower than the temperature of the intermediate working medium conveyed by the first cooling mechanism 2. In the circulation loop, the control mechanism adjusts the flow rate of the second part of the intermediate working medium refluxed and conveyed by the second cooling mechanism 5 to the first conveying mechanism 3 based on the temperature of the cooling medium of the first cooling mechanism 2, so that the second part of the intermediate working medium refluxed and conveyed by the second cooling mechanism 5 condenses and mixes with the intermediate working medium conveyed by the first cooling mechanism 2 for conveying, so as to improve the cooling capacity of the first conveying mechanism 3. Through the collaborative action of the first conveying mechanism 3 and the second conveying mechanism 4, the subcooling degree of the intermediate working medium in the waste heat recovery system based on reflux condensation is increased, the cooling effect is improved, the gas-liquid two-phase flow phenomenon is weakened, and the influence of cavitation is reduced.

[0085] The embodiments of the present invention have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention. Although the embodiments have been described separately above, this does not mean that the measures in each embodiment cannot be used advantageously in combination. The scope of the present invention is defined by the appended claims and their equivalents. Without departing from the scope of the present invention, those skilled in the art can make various substitutions and modifications, and these substitutions and modifications should fall within the scope of the present invention.

Claims

1. A waste heat recovery system based on reflux condensation, applicable to heat recovery of a heating device (9), characterized in that, Comprising: A conversion mechanism (1), configured to absorb the heat of the heating device (9) to form an initial working medium, convert the heat of the initial working medium into mechanical energy, and output an intermediate working medium; A first cooling mechanism (2), configured to cool the intermediate working medium through a cooling medium; A first conveying mechanism (3) and a second conveying mechanism (4) that are parallel to each other, respectively receiving and conveying the intermediate working medium conveyed by the first cooling mechanism (2); A second cooling mechanism (5), receiving the intermediate working medium conveyed by the first conveying mechanism (3) and / or the second conveying mechanism (4) and further cooling it. The first part of the cooled intermediate working medium is conveyed to the conversion mechanism (1) to form a circulation loop, and the second part of the cooled intermediate working medium is conveyed back to the first conveying mechanism (3); A control mechanism, based on the temperature of the cooling medium, adjusts the flow rate of the second part of the intermediate working medium conveyed back to the first conveying mechanism (3) by the second cooling mechanism (5), so that the second part of the intermediate working medium conveyed back by the second cooling mechanism (5) condenses and mixes with the intermediate working medium conveyed by the first cooling mechanism (2).

2. The waste heat recovery system based on reflux condensation according to claim 1, wherein The control mechanism is configured to, when the temperature of the cooling medium is greater than a preset temperature, close the second conveying mechanism (4), and adjust the flow rate of the intermediate working medium conveyed by the first conveying mechanism (3), so that the first part of the intermediate working medium conveyed by the second cooling mechanism (5) to the conversion mechanism (1) is cooled to a liquid state; When the temperature of the cooling medium is less than or equal to the preset temperature, adjust the flow rates of the intermediate working mediums conveyed by the first conveying mechanism (3) and the second conveying mechanism (4), so that the first part of the intermediate working medium conveyed by the second cooling mechanism (5) to the conversion mechanism (1) is cooled to a liquid state.

3. The waste heat recovery system based on reflux condensation according to claim 2, wherein Further comprising: A storage mechanism (6), arranged upstream of the second cooling mechanism (5), configured to receive the intermediate working medium conveyed by the first conveying mechanism (3) and / or the second conveying mechanism (4), and perform gas-liquid separation to form a gaseous intermediate working medium and a liquid intermediate working medium, and convey the liquid intermediate working medium to the second cooling mechanism (5); A driving mechanism (7), in response to the control mechanism, receiving the gaseous intermediate working medium conveyed by the storage mechanism (6), and pressurizing and conveying it to the first cooling mechanism (2) for further cooling.

4. The waste heat recovery system based on reflux condensation according to claim 3, wherein, The second cooling mechanism (5) includes: A heat exchange component (51), including a first conveying pipe (511) and a second conveying pipe (512) for receiving the liquid intermediate working medium conveyed by the storage mechanism (6); A first throttle valve (52), arranged at the inlet end of the second conveying pipe (512), to throttle and cool the liquid intermediate working medium conveyed by the second conveying pipe (512), so as to cool the liquid intermediate working medium conveyed by the first conveying pipe (511); Wherein, the liquid intermediate working medium in the first conveying pipe (511) is conveyed to the conversion mechanism (1), and the liquid intermediate working medium at the outlet end of the second conveying pipe (512) is conveyed to the first conveying mechanism (3).

5. The waste heat recovery system based on reflux condensation according to claim 3, characterized in that, The conversion mechanism (1) includes: The first heat exchange mechanism (11) is configured to absorb the heat of the heat supply device (9) to form an initial working medium; The expander (12) receives the initial working medium conveyed by the first heat exchange mechanism (11), converts the energy of the initial working medium into mechanical energy, and cools the initial working medium to form the intermediate working medium.

6. The waste heat recovery system based on reflux condensation according to claim 5, wherein The first conveying mechanism (3) includes: A conveying component (31) that responds to the control mechanism to receive and adjust the flow rate of the intermediate working medium conveyed by the first cooling mechanism (2), and receives the second part of the intermediate working medium conveyed by the second cooling mechanism (5) for mixed conveyance to the storage mechanism (6); A second throttle valve (32) that is parallel to the conveying component (31) and responds to the control mechanism to receive and adjust the flow rate of the intermediate working medium of the first cooling mechanism (2) flowing through the second throttle valve (32).

7. The waste heat recovery system based on reflux condensation according to claim 6, characterized in that, The conveying component (31) includes: An ejector (311) configured to receive and utilize the intermediate working medium conveyed by the expander (12) flowing through the first cooling mechanism (2) to eject the second part of the intermediate working medium conveyed by the second cooling mechanism (5); A first regulating valve (312) disposed between the first cooling mechanism (2) and the ejector (311), and responds to the control mechanism to adjust the flow rate of the intermediate working medium of the first cooling mechanism (2) flowing through the ejector (311).

8. The waste heat recovery system based on reflux condensation according to claim 3, wherein The second conveying mechanism (4) includes a second regulating valve (41) disposed between the first cooling mechanism (2) and the storage mechanism (6), and responds to the control mechanism to adjust the flow rate of the intermediate working medium conveyed by the first cooling mechanism (2) flowing through the second regulating valve (41).

9. The waste heat recovery system based on reflux condensation according to claim 5, characterized in that, It further includes a second heat exchange mechanism (8), including: A first heat exchange tube (81) communicating between the expander (12) and the first cooling mechanism (2) to receive the intermediate working medium conveyed by the expander (12); A second heat exchange tube (82) communicating between the second cooling mechanism (5) and the first heat exchange mechanism (11), receiving the first part of the intermediate working medium conveyed by the second cooling mechanism (5), and after absorbing the heat of the intermediate working medium in the first heat exchange tube (81), conveying it to the first heat exchange mechanism (11).

10. A waste heat recovery method based on the waste heat recovery system with reflux condensation according to any one of claims 2 to 9, applicable to the heat recovery of a heating device (9), characterized in that It includes: Utilize the conversion mechanism (1) to absorb the heat of the heat supply device (9) to form an initial working medium, convert the energy of the initial working medium into mechanical energy, and output an intermediate working medium; Cool the intermediate working medium through the cooling medium of the first cooling mechanism (2); Based on the temperature of the cooling medium, adjust the flow rate of the intermediate working medium conveyed by the second conveying mechanism (4) and / or the first conveying mechanism (3) to the second cooling mechanism (5); The second cooling mechanism (5) further cools the intermediate working medium conveyed from the second conveying mechanism (4) and / or the first conveying mechanism (3), conveys the cooled first part of the intermediate working medium to the conversion mechanism (1) to form a circulation loop, and based on the temperature of the cooling medium, adjusts the flow rate of the cooled second part of the intermediate working medium for reflux conveyance to the first conveying mechanism (3).

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