Efficient heat pump device for generating negative pressure steam and low-grade saturated steam waste heat utilization method

Abstract

The invention belongs to the technical field of energy conservation and environmental protection, and provides a negative-pressure-steam-generating efficient heat pump device and a low-grade saturated steam waste heat utilization method, and the negative-pressure-steam-generating efficient heat pump device and the low-grade saturated steam waste heat utilization method achieve waste heat recovery and energy grade improvement through a heat pump system. According to the device, the function of circulating cooling water condensation in the prior art is replaced, low-grade steam is condensed, the production negative pressure environment is guaranteed, originally discharged waste heat is converted into available negative pressure steam of 60-80 DEG C, and the problem of resource waste is solved; the negative pressure steam separation chamber is arranged, so that efficient separation of useful steam is ensured, waste heat recycling is achieved, and the development requirements of industrial energy conservation and emission reduction and resource recycling are completely met.

Description

Technical Field

[0001] This invention belongs to the field of energy conservation and environmental protection technology, specifically relating to a high-efficiency heat pump device for generating negative pressure steam and a method for utilizing waste heat from low-grade saturated water steam. Background Technology

[0002] In many industrial production sectors such as chemical, pharmaceutical, food processing, textile, and electronics manufacturing, low-grade saturated water vapor with a temperature range of 35℃ to 55℃ is commonly generated during process steps (such as material drying, reactor heat exchange, and distillation purification). Due to its low energy density, large pressure fluctuations, and the presence of trace amounts of process impurities or moisture in some scenarios, this type of water vapor cannot be directly reused in existing core production processes and has long been defined by the industry as "worthless waste heat," failing to achieve effective resource utilization.

[0003] To ensure the stability of the negative pressure (vacuum) environment required for the production process and to avoid the accumulation of waste heat steam affecting production continuity, the existing technology generally adopts the treatment mode of "circulating cooling water condensation + vacuum pump exhaust": First, through the circulating cooling water condensation system, the continuously flowing cooling water is used to conduct forced heat exchange with low-grade saturated water vapor, so that the steam is condensed into liquid water; then the vacuum pump is started to extract the non-condensable gases (such as air, trace amounts of process exhaust gas, etc.) that were not liquefied during the condensation process, thereby maintaining the negative pressure state required in the system and ensuring the normal progress of the production process.

[0004] However, the existing treatment technologies mentioned above have the problem of resource waste. Although the energy density per unit volume of low-grade saturated water vapor at 35℃~55℃ is low, the total amount generated in industrial production is huge. The heat energy contained in it is completely absorbed by the circulating cooling water during the condensation process and then directly discharged into the environment, resulting in a large amount of unusable heat energy being lost without value, which is contrary to the current development requirements of energy conservation, emission reduction and resource recycling in the industrial field. Summary of the Invention

[0005] This invention provides a high-efficiency heat pump device for generating negative pressure steam and a method for utilizing waste heat from low-grade saturated water steam, aiming to solve the technical problems mentioned in the background art.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: In a first aspect, embodiments of the present invention provide a high-efficiency heat pump device for generating negative pressure steam, comprising a heat pump system and a negative pressure steam separation chamber. The heat pump system is provided with a heat absorption section and a heat release section. The heat absorption section is used to absorb heat from low-grade saturated water vapor, causing the low-grade saturated water vapor to condense. The heat release section is used to heat the pure water inside the heat release section to 60°C~80°C using the absorbed heat. The negative pressure steam separation chamber is connected to the heat release section and is used to separate 60°C~80°C negative pressure saturated water vapor from the pure water.

[0007] In conjunction with the first aspect, in one possible implementation of the high-efficiency heat pump device for generating negative pressure steam provided by the present invention, the heat pump system includes an evaporative heat exchanger, a compressor, a condensing heat exchanger, and a throttling valve. The evaporative heat exchanger is the heat-absorbing part, used to introduce low-grade saturated water vapor and exchange heat with it, causing the internal refrigerant to absorb heat and vaporize, generating a low-temperature, low-pressure gaseous refrigerant. The compressor is used to draw in the low-temperature, low-pressure gaseous refrigerant generated by the evaporative heat exchanger, and... The low-temperature, low-pressure gaseous refrigerant is compressed and heated to transform into a high-temperature, high-pressure gaseous refrigerant. The condensing heat exchanger is the heat-releasing section, containing pure water to be heated. The high-temperature, high-pressure gaseous refrigerant enters the condensing heat exchanger, releases latent heat, and forms a medium-temperature, high-pressure liquid refrigerant, which heats the pure water to 60°C~80°C. The throttling valve controls the medium-temperature, high-pressure liquid refrigerant, reducing its pressure and temperature to form a gas-liquid mixture, which then enters the evaporating heat exchanger to begin the next cycle.

[0008] In conjunction with the first aspect, in one possible implementation of the high-efficiency heat pump device for generating negative pressure steam provided by the present invention, the condensing heat exchanger includes: The casing contains pure water, and has a refrigerant inlet and refrigerant outlet on the side, and a water inlet at the bottom. A heat exchange assembly includes a heat exchange chamber and multiple heat exchange tubes. A downcomer is provided in the middle of the heat exchange chamber, which runs vertically through the heat exchange chamber. Multiple heat exchange tubes are arranged vertically and spaced apart around the downcomer in the heat exchange chamber, and their two ends are connected to the outside of the heat exchange chamber. The space inside the heat exchange cavity and between the heat exchange tubes together form the shell side of the heat exchanger, and is connected to the refrigerant inlet and the refrigerant outlet to allow the high-temperature and high-pressure gaseous refrigerant to circulate. The upper and lower spaces of the heat exchange chamber, the interior of the heat exchange tube, and the interior of the downcomer together form the heat exchanger tube side, which is used to circulate pure water and exchange heat with the high-temperature and high-pressure gaseous refrigerant.

[0009] In conjunction with the first aspect, in one possible implementation of the high-efficiency heat pump device for generating negative pressure steam provided by the present invention, the negative pressure steam separation chamber is located on the upper side of the shell and communicates with the interior of the shell.

[0010] In conjunction with the first aspect, in one possible implementation of the high-efficiency heat pump device for generating negative pressure steam provided by the present invention, the height of the heat exchange tube is ≤0.5m.

[0011] In conjunction with the first aspect, in one possible implementation of the high-efficiency heat pump device for generating negative pressure steam provided by the present invention, the heat exchange chamber includes an upper tube sheet, a lower tube sheet, and the downcomer. The upper tube sheet and the lower tube sheet are both annular and are respectively disposed at both ends of the heat exchange tube. The outer edge is connected to the shell and the inner edge is connected to the downcomer. The heat exchange tube passes through the upper tube sheet and the lower tube sheet.

[0012] Secondly, embodiments of the present invention provide a method for utilizing waste heat from low-grade saturated water vapor, comprising: A heat pump system is used to absorb the heat from low-grade saturated water vapor, heating pure water to 60°C~80°C, and causing the absorbed low-grade saturated water vapor to condense. The negative pressure steam separation chamber separates 60℃~80℃ negative pressure saturated steam from heated pure water, and supplies it to users as a steam heat source for heating water that can utilize the corresponding grade of negative pressure saturated steam.

[0013] In conjunction with the second aspect, in one possible implementation of the low-grade saturated water vapor waste heat utilization method provided by the present invention, an annular heat exchange cavity is provided in the middle of the condensing heat exchanger in the heat pump system, a downcomer is formed in the middle of the heat exchange cavity, and multiple heat exchange tubes penetrating the heat exchange cavity are arranged around the downcomer; and the height of the heat exchange tubes is ≤0.5m.

[0014] The beneficial effects of the high-efficiency heat pump device for generating negative pressure steam and the method for utilizing waste heat from low-grade saturated water steam provided by this invention are as follows: Compared with the prior art, the high-efficiency heat pump device for generating negative pressure steam and the method for utilizing waste heat from low-grade saturated water steam provided by this invention achieve waste heat recovery and energy grade improvement through a heat pump system. It not only replaces the function of "circulating cooling water condensation" in the prior art, enabling the condensation of low-grade steam and ensuring a negative pressure environment for production; it also converts the originally emitted waste heat into usable negative pressure steam at 60℃~80℃, solving the problem of resource waste. The setting of the negative pressure steam separation chamber ensures the efficient separation of useful steam, realizing "waste heat resource utilization," which fully meets the development requirements of industrial energy conservation, emission reduction, and resource recycling. Attached Figure Description

[0015] Figure 1 A schematic diagram of a high-efficiency heat pump device for generating negative pressure steam provided in an embodiment of the present invention; Figure 2 This is a cross-sectional view of the condensing heat exchanger and the negative pressure steam separation chamber in the high-efficiency heat pump device for generating negative pressure steam provided in an embodiment of the present invention. Figure 3 A top view of the condenser heat exchanger in the high-efficiency heat pump device for generating negative pressure steam provided in an embodiment of the present invention; Explanation of reference numerals in the attached figures: 1. Evaporative heat exchanger; 2. Expansion valve; 3. Compressor; 4. Condensative heat exchanger; 41. Shell; 411. Refrigerant inlet; 412. Refrigerant outlet; 42. Upper tube sheet; 43. Lower tube sheet; 44. Downcomer; 45. Heat exchanger tubes; 5. Negative pressure steam separation chamber; 6. Steam-using equipment. Detailed Implementation

[0016] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0017] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. The following description of at least one exemplary embodiment is actually illustrative only and is in no way intended to limit this application or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0018] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0019] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this application. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0020] In the description of this application, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is usually based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this application and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this application; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0021] For ease of description, spatial relative terms such as "above," "over," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "above" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways, and the spatial relative descriptions used herein will be interpreted accordingly.

[0022] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0023] Please refer to the following: Figures 1 to 3 The present invention will now describe the high-efficiency heat pump device for generating negative pressure steam. The high-efficiency heat pump device for generating negative pressure steam includes a heat pump system and a negative pressure steam separation chamber 5. The heat pump system has a heat absorption section and a heat release section. The heat absorption section absorbs heat from low-grade saturated water vapor, causing the low-grade saturated water vapor to condense. The heat release section uses the absorbed heat to heat the pure water inside the heat release section to 60°C~80°C. The negative pressure steam separation chamber 5 is connected to the heat release section and is used to separate 60°C~80°C negative pressure saturated water vapor from the pure water.

[0024] It should be noted that in this embodiment, the temperature range of the low-grade saturated water vapor corresponds to the 35℃~55℃ industrial waste heat steam described in the background art. The trace process impurities or moisture it carries will not affect the heat exchange function of the heat absorption section of the heat pump system, and no additional pretreatment module is required. The "pure water" heated by the heat release section is clean water without process contaminants, which avoids the negative pressure saturated water vapor produced being contaminated and is suitable for the cleanliness requirements of heat source in industrial production. The temperature setting of 60℃~80℃ forms a reasonable energy gradient with the low-grade waste heat steam, ensuring the heat exchange efficiency of the heat pump system. The generated water vapor is used to supply steam-using equipment 6.

[0025] The specific temperature of the negative pressure saturated water vapor produced by the device can be set arbitrarily between 60℃ and 80℃ as needed.

[0026] The beneficial effects of the high-efficiency heat pump device for generating negative pressure steam provided in this invention embodiment are as follows: Compared with the prior art, the high-efficiency heat pump device for generating negative pressure steam provided in this invention embodiment realizes waste heat recovery and energy grade improvement through the heat pump system. It not only replaces the function of "circulating cooling water condensation" in the prior art, enabling the condensation of low-grade steam and ensuring a negative pressure environment for production; it also converts the originally emitted waste heat into usable negative pressure steam at 60℃~80℃, solving the problem of resource waste. The setting of the negative pressure steam separation chamber 5 ensures the efficient separation of useful steam, realizing "waste heat resource utilization," which fully meets the development requirements of industrial energy conservation, emission reduction, and resource recycling.

[0027] like Figure 1 and Figure 2 As shown, in a specific embodiment of the high-efficiency heat pump device for generating negative pressure steam provided in this invention, the heat pump system includes an evaporative heat exchanger 1, a compressor 3, a condensing heat exchanger 4, and a throttling valve 2. The evaporative heat exchanger 1 is the heat-absorbing part, used to introduce low-grade saturated water vapor and exchange heat with it, causing the internal refrigerant to absorb heat and vaporize, generating a low-temperature, low-pressure gaseous refrigerant. The compressor 3 is used to draw in the low-temperature, low-pressure gaseous refrigerant generated by the evaporative heat exchanger 1. The refrigerant is compressed and heated from a low-temperature, low-pressure gaseous refrigerant to a high-temperature, high-pressure gaseous refrigerant. The condensing heat exchanger 4 is the heat release section, which contains pure water to be heated. The high-temperature, high-pressure gaseous refrigerant enters the condensing heat exchanger 4, releases latent heat, and forms a medium-temperature, high-pressure liquid refrigerant, which heats the pure water to 60℃~80℃. The throttling valve 2 controls the medium-temperature, high-pressure liquid refrigerant. After depressurization and cooling, it forms a gas-liquid mixture and enters the evaporating heat exchanger 1 to start the next cycle.

[0028] It should be noted that in this embodiment, the compression ratio of compressor 3 is designed to match the energy requirements of "heat absorption by low-grade steam at 35℃~55℃" and "heating of pure water to 60℃~80℃", ensuring that the refrigerant can achieve efficient energy transfer. The latent heat released by the refrigerant in the condenser heat exchanger 4 is the main form of heat exchange, which is more efficient than sensible heat and can quickly heat pure water to the target temperature, meeting the continuous production needs of industrial processes. Precise control of the expansion valve 2 ensures stable refrigerant circulation and avoids a decrease in heat exchange efficiency due to fluctuations in operating conditions.

[0029] The refrigerant is Freon, preferably R410a, R152a or R134a.

[0030] In this embodiment, the heat pump system constructs an efficient energy transfer path through a closed-loop cycle of "evaporation-compression-condensation-throttling," solving the problem that low-grade steam is difficult to utilize directly due to its low temperature. Compared to the existing "cooling water condensation + vacuum pump" mode, this system does not require the consumption of a large amount of cooling water and avoids the secondary energy waste caused by cooling water carrying away heat.

[0031] Meanwhile, the compressor 3's process of increasing the pressure and temperature of the refrigerant realizes the upgrading of low-grade heat energy to medium-grade heat energy, giving waste heat practical application value. Moreover, the entire system has low energy consumption during operation, further improving the energy utilization efficiency of industrial production.

[0032] like Figure 1 and Figure 2 As shown, in a specific embodiment of the high-efficiency heat pump device for generating negative pressure steam provided in this invention, the condensing heat exchanger 4 includes a shell 41 and a heat exchange assembly. The shell 41 is used to contain pure water, and has a refrigerant inlet 411 and a refrigerant outlet 412 on its side, and a water inlet at its bottom. The heat exchange assembly includes a heat exchange chamber and a plurality of heat exchange tubes 45. A downcomer 44 is provided in the middle of the heat exchange chamber, which is vertically penetrating the heat exchange chamber. The plurality of heat exchange tubes 45 are arranged vertically and spaced around the downcomer 44 in the heat exchange chamber, and their two ends are connected to the outside of the heat exchange chamber.

[0033] The space between the heat exchanger tubes 45 and the interior of the heat exchanger cavity together form the shell side of the heat exchanger, which is connected to the refrigerant inlet 411 and the refrigerant outlet to circulate high-temperature and high-pressure gaseous refrigerant.

[0034] The upper and lower spaces of the heat exchange chamber, the interior of the heat exchange tube 45, and the interior of the downcomer 44 together form the heat exchanger tube side, which is used to circulate pure water and exchange heat with the high-temperature and high-pressure gaseous refrigerant.

[0035] It should be noted that in this embodiment, under the action of heat, the heat transfer density of the peripheral heat exchange tube 45 is high, causing the liquid flow to rise, while the liquid flow in the central tube is lower, so that the pure water can circulate naturally.

[0036] like Figure 1 and Figure 2 As shown, in a specific embodiment of the high-efficiency heat pump device for generating negative pressure steam provided in this invention, the negative pressure steam separation chamber 5 is located on the upper side of the shell 41 and communicates with the interior of the shell 41.

[0037] It should be noted that in this embodiment, the design of the negative pressure steam separation chamber 5 being directly connected to the upper side of the shell 41 can utilize the characteristic of pure water rising naturally after heating, so that the generated saturated water vapor can enter the separation chamber without additional power, thus simplifying the device structure.

[0038] Meanwhile, this arrangement shortens the steam flow path, reduces heat loss during steam transmission, and ensures that the separated negative pressure steam temperature remains stable at 60℃~80℃, thus guaranteeing the steam quality.

[0039] In this embodiment, the design directly solves the potential problems of steam separation requiring additional power or large transmission losses in the prior art. By optimizing the spatial layout, the steam separation efficiency and energy utilization rate are improved. The simplified structural design reduces the manufacturing cost and maintenance difficulty of the device, while reducing heat loss during steam transmission, ensuring that the produced negative pressure steam can stably meet the user's heating needs, and further enhancing the practicality of waste heat resource utilization.

[0040] In one specific embodiment of the high-efficiency heat pump device for generating negative pressure steam provided in this invention, the height of the heat exchange tube 45 is ≤0.5m.

[0041] It should be noted that in this embodiment, the design of the heat exchange tube 45 with a height of ≤0.5m is determined based on the characteristics of low-grade waste heat exchange and the influence of static pressure boiling point rise.

[0042] On the one hand, a shorter pipe length can reduce the flow resistance of pure water in the pipe, accelerate the water circulation speed, and improve the heat exchange efficiency. On the other hand, it can avoid uneven heat exchange caused by excessively long pipes, ensuring that the pure water in the pipe can evenly absorb the heat released by the refrigerant and quickly reach the target temperature of 60℃~80℃.

[0043] On the other hand, it effectively solves the problem that "if the heat exchange tube height is too high, the boiling point of the deep liquid level will rise due to static pressure, affecting the effective heat transfer." If the heat exchange tube height is too high, the boiling point of the pure water in the deep liquid level will rise due to the static pressure of the liquid column, causing the actual evaporation temperature to deviate from the target range of 60℃~80℃, disrupting the effective heat transfer temperature difference between the refrigerant and pure water, and significantly reducing the heat exchange efficiency. A tube height of ≤0.5m can significantly reduce the impact of liquid column static pressure, avoid abnormal rise in boiling point, and ensure a stable heat transfer temperature difference.

[0044] In this embodiment, the size limitation specifically addresses the following issues: First, the problem of high flow resistance and uneven heat exchange in the long heat exchange tube 45 is solved by shortening the tube height, thereby improving water circulation efficiency and heat exchange uniformity. Second, the problem of static pressure boiling point rise caused by the high heat exchange tube 45 is solved by avoiding abnormal temperature rise of pure water in deep liquid levels, ensuring effective heat transfer temperature difference, and ensuring stable vaporization of pure water within the target temperature range.

[0045] like Figure 2 and Figure 3 As shown, in a specific embodiment of the high-efficiency heat pump device for generating negative pressure steam provided in this invention, the heat exchange chamber includes an upper tube sheet 42, a lower tube sheet 43, and a downcomer 44. The upper tube sheet 42 and the lower tube sheet 43 are both annular and are respectively located at both ends of the heat exchange tube 45. The outer edge is connected to the shell 41, and the inner edge is connected to the downcomer 44. The heat exchange tube 45 passes through the upper tube sheet 42 and the lower tube sheet 43.

[0046] It should be noted that, in this embodiment, the design of the annular upper tube sheet 42 and lower tube sheet 43 can accurately fix the position of the heat exchange tube 45 and the downcomer 44, ensuring the stability of the layout of multiple heat exchange tubes 45 surrounding the downcomer 44 and avoiding component displacement caused by fluid impact.

[0047] The connection between the outer edge of the tube sheet and the shell 41, and the inner edge and the downcomer 44, ensures the sealing performance of the shell side and the tube side, preventing refrigerant and pure water from leaking or permeating each other, and ensuring the safe operation of the unit. The design of the heat exchange tube 45 penetrating the tube sheet creates a continuous fluid channel inside the tube side, ensuring the smooth circulation of pure water. At the same time, in conjunction with the height design of the heat exchange tube 45 ≤ 0.5m, it further enhances the effect of resisting static pressure boiling point rise.

[0048] In this embodiment, the structural design solves the problems of installation stability and sealing reliability of the heat exchange components. The fixing and sealing effect of the annular tube sheet improves the operational safety and stability of the device. Simultaneously, the orderly component layout facilitates later maintenance and replacement, reducing equipment operation and maintenance costs. The guaranteed sealing performance avoids refrigerant and pure water mixing contamination, ensuring the cleanliness of the produced negative pressure steam. Furthermore, in conjunction with the short heat exchange tube 45 design, it further ensures effective heat transfer, adapting to the usage requirements of demanding industrial scenarios.

[0049] Based on the same inventive concept, embodiments of the present invention provide a method for utilizing waste heat from low-grade saturated water vapor, comprising: By using a heat pump system, heat is absorbed from low-grade saturated water vapor to heat pure water to 60℃~80℃, and the low-grade saturated water vapor is condensed. The negative pressure steam separation chamber 5 separates 60℃~80℃ negative pressure saturated steam from heated pure water, and supplies it to users as a steam heat source for heating water that can utilize the corresponding grade of negative pressure saturated steam.

[0050] The beneficial effects of the low-grade saturated steam waste heat utilization method provided by this invention are as follows: Compared with the prior art, the low-grade saturated steam waste heat utilization method provided by this invention realizes waste heat recovery and energy grade improvement through a heat pump system. It not only replaces the function of "circulating cooling water condensation" in the prior art (condensing low-grade steam to ensure a negative pressure environment for production), but also converts the originally emitted waste heat into usable negative pressure steam at 60℃~80℃, solving the problem of resource waste. The setting of the negative pressure steam separation chamber 5 ensures the efficient separation of useful steam, realizing "waste heat resource utilization", which fully meets the development requirements of industrial energy conservation, emission reduction and resource recycling.

[0051] In conjunction with the second aspect, in one possible implementation of the low-grade saturated water vapor waste heat utilization method provided by the present invention, an annular heat exchange cavity is provided in the middle of the condensing heat exchanger 4 in the heat pump system, a downcomer 44 is formed in the middle of the heat exchange cavity, and multiple heat exchange tubes 45 penetrating the heat exchange cavity are arranged around the downcomer 44; and the height of the heat exchange tubes 45 is ≤0.5m.

[0052] It should be noted that, in this embodiment, the design of the annular heat exchange chamber and the downcomer 44 is to construct an efficient heat exchange circulation path during the method execution process, enabling pure water to form a smooth circulation flow between the heat exchange tube 45 and the downcomer 44, thereby improving heat exchange uniformity. The limitation of the height of the heat exchange tube 45 to ≤0.5m ensures the technical effect of low pure water flow resistance and high heat exchange efficiency. On the other hand, it solves the problem of "high heat exchange tube 45 causing the boiling point of deep liquid level static pressure to rise and the temperature to increase"—if the heat exchange tube 45 is too high, the boiling point of the pure water in the deep liquid level will rise due to the influence of the liquid column static pressure, causing the evaporation temperature to deviate from the target range, destroying the heat transfer temperature difference, and affecting the heat exchange effectiveness. This size design can significantly reduce the influence of static pressure on the boiling point, maintain a stable heat transfer temperature difference, ensure effective heat transfer, and adapt to the heat exchange requirements of low-grade waste heat with "large total amount and low energy density". The limitation of these structural parameters makes the method operable, ensuring that the goal of heating pure water to 60℃~80℃ can be stably achieved in different implementation scenarios.

[0053] In this embodiment, the method further optimizes the efficiency and stability of waste heat utilization by clarifying the specific structural parameters of the condensing heat exchanger 4. It not only solves the technical pain points of "low efficiency and uneven heat exchange" in the process of low-grade waste heat exchange, but also precisely overcomes the core problem of temperature rise caused by static pressure boiling point rise, which affects effective heat transfer. The combined design of the annular heat exchange cavity and the short heat exchange tube 45 ensures the high efficiency of heat energy absorption and transfer at the method level, and significantly improves the conversion rate of waste heat recovery.

[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-efficiency heat pump device for generating negative pressure steam, characterized in that, include: The heat pump system is equipped with a heat absorption section and a heat release section. The heat absorption section is used to absorb the heat of low-grade saturated water vapor and condense the low-grade saturated water vapor. The heat release section is used to heat the pure water inside the heat release section to 60°C~80°C using the absorbed heat. The negative pressure steam separation chamber (5) is connected to the heat release section and is used to separate 60°C~80°C negative pressure saturated water vapor from the pure water.

2. The high-efficiency heat pump device for generating negative pressure steam as described in claim 1, characterized in that, The heat pump system includes: Evaporative heat exchanger (1) is the heat absorption part, used to introduce low-grade saturated water vapor and exchange heat with low-grade saturated water vapor, so that the refrigerant inside absorbs heat and vaporizes to generate low-temperature and low-pressure gaseous refrigerant. The compressor (3) is used to draw in the low-temperature, low-pressure gaseous refrigerant generated by the evaporative heat exchanger (1), and to compress and heat the low-temperature, low-pressure gaseous refrigerant to convert it into a high-temperature, high-pressure gaseous refrigerant. The condensing heat exchanger (4) is the heat release part, and the pure water to be heated is provided inside. The high temperature and high pressure gaseous refrigerant enters the condensing heat exchanger (4), releases latent heat, forms a medium temperature and high pressure liquid refrigerant, and heats the pure water to 60℃~80℃. The throttle valve (2) controls the medium-temperature and high-pressure liquid refrigerant. After the pressure and temperature are reduced, a gas-liquid mixture of refrigerant is formed and enters the evaporative heat exchanger (1) to start the next cycle.

3. The high-efficiency heat pump device for generating negative pressure steam as described in claim 2, characterized in that, The condensing heat exchanger (4) includes: The shell (41) is used to hold pure water inside, and has a refrigerant inlet (411) and a refrigerant outlet (412) on the side, and a water inlet at the bottom; The heat exchange assembly includes a heat exchange cavity and multiple heat exchange tubes (45). A downcomer (44) is provided in the middle of the heat exchange cavity, which runs vertically through the heat exchange cavity. The multiple heat exchange tubes (45) are arranged vertically and spaced apart around the downcomer (44) in the heat exchange cavity, and their two ends are connected to the outside of the heat exchange cavity. The space between the heat exchange chamber and the heat exchange tubes (45) together form the shell side of the heat exchanger, and is connected to the refrigerant inlet (411) and the refrigerant outlet (412) to circulate the high-temperature and high-pressure gaseous refrigerant. The upper and lower spaces of the heat exchange chamber, the interior of the heat exchange tube (45), and the interior of the downcomer (44) together form the heat exchanger tube side, which is used to circulate pure water and exchange heat with the high-temperature and high-pressure gaseous refrigerant.

4. The high-efficiency heat pump device for generating negative pressure steam as described in claim 3, characterized in that, The negative pressure steam separation chamber (5) is located on the upper side of the shell (41) and communicates with the interior of the shell (41).

5. The high-efficiency heat pump device for generating negative pressure steam as described in claim 3, characterized in that, The height of the heat exchange tube (45) is ≤0.5m.

6. The high-efficiency heat pump device for generating negative pressure steam as described in claim 3, characterized in that, The heat exchange chamber includes an upper tube sheet (42), a lower tube sheet (43), and a downcomer (44). The upper tube sheet (42) and the lower tube sheet (43) are both annular and are respectively located at both ends of the heat exchange tube (45). The outer edge is connected to the shell (41), and the inner edge is connected to the downcomer (44). The heat exchange tube (45) passes through the upper tube sheet (42) and the lower tube sheet (43).

7. A method for utilizing waste heat from low-grade saturated water steam, characterized in that, include: A heat pump system is used to absorb the heat from low-grade saturated water vapor, heating pure water to 60°C~80°C, and causing the absorbed low-grade saturated water vapor to condense. The negative pressure steam separation chamber (5) separates 60℃~80℃ negative pressure saturated steam from the heated pure water, and supplies it to the user as a heating water steam heat source that can utilize the corresponding grade of negative pressure saturated steam.

8. The method for utilizing waste heat from low-grade saturated water steam as described in claim 7, characterized in that, An annular heat exchange chamber is provided in the middle of the condensing heat exchanger (4) in the heat pump system. A downcomer (44) is formed in the middle of the heat exchange chamber. Multiple heat exchange tubes (45) are provided around the downcomer (44) and penetrate the heat exchange chamber. The height of the heat exchange tubes (45) is ≤0.5m.

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