Black water waste heat recovery system and method

Abstract

The application discloses a black water waste heat recovery system and method, which comprises a black water flash device, an absorption heat pump device and a water preheating device to be heated; wherein the input end of a high-temperature steam output pipeline, the output end of a high-temperature condensate water return pipeline, the input end of a first steam external supply pipeline and the input end of a low-temperature steam output pipeline are arranged along the black water conveying direction of the black water flash device; the water preheating device to be heated, a condenser and an absorber are connected along the water conveying direction of the water to be heated, and the output end of a black water output pipeline is connected to the water preheating device to be heated; the output end of the high-temperature steam output pipeline is connected to the hot side input end of a generator, the input end of the high-temperature condensate water return pipeline is connected to the hot side output end of the generator, and the output end of the low-temperature steam output pipeline is connected to the hot side input end of an evaporator. The application builds a more reasonable temperature gradient, realizes more efficient energy gradient utilization, fully excavates the potential of a low-temperature heat source and significantly enhances the waste heat recovery capacity of the system.

Description

Technical Field

[0001] This invention relates to the field of coal chemical heat recovery technology, and in particular, to a black water waste heat recovery system and method. Background Technology

[0002] Coal gasification technology, as a core means of clean and efficient coal conversion, can not only transform coal into clean fuel gas, oil products, and high-end chemical raw materials, improving the economic and environmental benefits of coal utilization, but also effectively reduce emissions of pollutants such as sulfur dioxide, nitrogen oxides, and particulate matter. It is a key technology for realizing the transformation of coal from fuel to raw material and ensuring energy security. However, a large amount of high-temperature black water is generated during the gasification process. For a long time, the large amount of steam generated during the black water flash evaporation process has typically relied on circulating water for cooling and condensation, resulting in ineffective recovery of waste heat. This not only leads to significant waste of thermal energy resources but also increases the overall operating cost of the plant.

[0003] Existing technologies primarily improve the efficiency of blackwater waste heat recovery by optimizing flash tank layout, direct heat exchange, indirect heat exchange, and heat-work integration. Optimizing flash tank layout mainly involves improving the structural design and system configuration of the flash tank to enhance flash efficiency and heat recovery capabilities. For example, multi-stage flash evaporation or pressure coupling designs can be used to extract waste heat of different qualities at each stage. Direct heat exchange technology typically utilizes direct contact between blackwater and the cooling medium to transfer heat, offering the advantage of simple equipment. Indirect heat exchange uses wall heat transfer, employing heat exchangers to achieve heat exchange between blackwater and the working medium. Although more expensive, it effectively avoids medium contamination issues and is suitable for recovery scenarios with high water quality requirements. Heat-work integration further converts waste heat into mechanical or electrical energy, for example, by using flash steam to drive turbines or integrating low-grade thermal power generation devices to achieve improved energy quality and comprehensive utilization. These preferred methods can be flexibly configured and integrated according to specific process requirements and project conditions, continuously promoting energy conservation, emission reduction, and cleaner production levels in coal gasification plants.

[0004] However, existing blackwater waste heat recovery systems have significant shortcomings in energy cascade utilization, failing to classify and rationally allocate heat according to the actual grade of the blackwater heat source. High-temperature heat is often mixed with low-temperature heat for processing, high-grade heat energy is not prioritized for power generation or driving high-energy-consuming equipment, while low-grade heat energy lacks effective cooling and cascade utilization, resulting in serious energy waste and low utilization efficiency. Summary of the Invention

[0005] The purpose of this invention is to provide a blackwater waste heat recovery system and method to solve the technical problems of insufficient energy cascade utilization in existing blackwater waste heat recovery systems, which leads to serious energy quality waste and low utilization efficiency.

[0006] The above-mentioned objectives of the present invention can be achieved by the following technical solutions: This invention provides a blackwater waste heat recovery system, including a blackwater flash evaporation device, an absorption heat pump device, and a preheating device for the water to be heated. The absorption heat pump device includes a generator, an absorber, a condenser, and an evaporator. The blackwater flash evaporation device is equipped with a high-temperature steam output pipeline, a high-temperature condensate return pipeline, a first external steam supply pipeline, a low-temperature steam output pipeline, and a blackwater output pipeline. The input end of the high-temperature steam output pipeline, the output end of the high-temperature condensate return pipeline, the input end of the first external steam supply pipeline, and the output end of the low-temperature steam output pipeline are all connected. The input ends are arranged along the black water conveying direction of the black water flash evaporation device; the cold side of the preheating device for the water to be heated, the cold side of the condenser, and the cold side of the absorber are connected along the water conveying direction for the water to be heated; the output end of the black water output pipeline is connected to the hot side input end of the preheating device for the water to be heated; the output end of the high-temperature steam output pipeline is connected to the hot side input end of the generator; the input end of the high-temperature condensate return pipeline is connected to the hot side output end of the generator; and the output end of the low-temperature steam output pipeline is connected to the hot side input end of the evaporator.

[0007] In an embodiment of the present invention, the black water waste heat recovery system further includes a steam generator to be heated, the steam generator to be heated is connected to the cold side output end of the absorber, and the steam generator to be heated is provided with a second external steam supply pipeline.

[0008] In an embodiment of the present invention, the steam generator for heating water includes a flash tank for heating water, and the steam output end of the flash tank for heating water is connected to the input end of the second external steam supply pipeline.

[0009] In an embodiment of the present invention, the black water flash evaporation device is further provided with a water input pipeline to be heated. The output end of the water input pipeline to be heated is located between the output end of the high-temperature condensate return pipeline and the input end of the low-temperature steam output pipeline in the direction of black water transportation. The input end of the water input pipeline to be heated is connected to the liquid phase output end of the water vapor generator to be heated.

[0010] In an embodiment of the present invention, the black water flash evaporation device includes a high-pressure flash tank, a low-pressure flash tank, and a vacuum flash tank connected sequentially along its black water conveying direction. The steam output end of the high-pressure flash tank is connected to the input end of the high-temperature steam output pipeline, the steam output end of the low-pressure flash tank is connected to the input end of the first external steam supply pipeline, the liquid phase output end of the vacuum flash tank is connected to the black water output pipeline, the output end of the high-temperature condensate return pipeline is connected between the high-pressure flash tank and the low-pressure flash tank, and the output end of the water to be heated input pipeline is connected between the low-pressure flash tank and the vacuum flash tank.

[0011] In an embodiment of the present invention, the black water flash evaporation device further includes a first mixer and a second mixer. The first mixer is connected to the liquid phase output end of the high-pressure flash tank and the liquid phase input end of the low-pressure flash tank, and is connected to the output end of the high-temperature condensate return pipeline. The second mixer is connected to the liquid phase output end of the low-pressure flash tank and the liquid phase input end of the vacuum flash tank, and is connected to the output end of the water to be heated input pipeline.

[0012] In an embodiment of the present invention, the generator and the absorber are connected to form a solution circulation loop via a dilute solution delivery pipeline and a concentrated solution delivery pipeline. The generator is connected to one end of the refrigerant water delivery pipeline via the condenser, and the absorber is connected to the other end of the refrigerant water delivery pipeline via the evaporator. The absorption heat pump device further includes a solution heat exchanger, which is located in the concentrated solution delivery pipeline and the dilute solution delivery pipeline to exchange heat between the concentrated solution and the dilute solution.

[0013] In an embodiment of the present invention, the hot side input end of the absorber is provided with a concentrated solution spraying structure, and the concentrated solution delivery pipeline is provided with a solution control valve between the absorber and the solution heat exchanger.

[0014] In an embodiment of the present invention, the cold side input end of the evaporator is provided with a refrigerant water spray structure, and the refrigerant water delivery pipeline is provided with a refrigerant water control valve.

[0015] In an embodiment of the present invention, the cold side input end of the generator is provided with a dilute solution spraying structure, and the dilute solution delivery pipeline is provided with a solution pump between the absorber and the solution heat exchanger.

[0016] This invention also provides a method for recovering waste heat from black water, employing the aforementioned black water waste heat recovery system. The method includes the following steps: Black water side startup: High-temperature black water is transported to the black water flash evaporator for flash evaporation. First, the generated high-temperature steam is transported to the hot side of the generator. Then, after the low-temperature steam generated by the black water flash evaporator reaches its preset temperature, the low-temperature steam is transported to the hot side of the evaporator. Finally, the flash-evaporated low-temperature black water is transported to the hot side of the preheating device for the water to be heated. Heat pump side startup: A dilute solution is transported to the cold side of the generator. When the temperature of the dilute solution in the generator rises to its preset temperature, the refrigerant water vapor in the generator is transported to the hot side of the condenser. When refrigerant water at the preset temperature is generated on the hot side of the condenser… Refrigerant water is supplied to the cold side of the evaporator; after the refrigerant water exchanges heat with low-temperature steam to form refrigerant water vapor at a preset temperature, the refrigerant water vapor is supplied to the hot side of the absorber; the concentrated solution generated on the cold side of the generator is supplied to the hot side of the absorber; the water to be heated side is started: the water to be heated is fed into the cold side of the water to be heated preheating device to exchange heat with low-temperature black water; after the water to be heated in the water to be heated preheating device reaches a preset temperature, the preheated water to be heated is supplied to the cold side of the condenser to exchange heat with refrigerant water vapor; after the water to be heated in the condenser reaches a preset temperature, the water to be heated is supplied to the cold side of the absorber; after the water to be heated in the absorber reaches a preset temperature, the black water waste heat recovery system enters the stable operation stage.

[0017] In an embodiment of the present invention, the blackwater waste heat recovery method further includes adjusting the blackwater waste heat recovery system during the stable operation phase: monitoring the output parameters of the external heat source supplied by the blackwater waste heat recovery system; analyzing and determining the real-time load of the external heat source based on the output parameters of the external heat source; and adjusting the blackwater waste heat recovery system according to the real-time load and load demand of the external heat source under different load conditions.

[0018] The features and advantages of this invention are: The black water waste heat recovery system and method of the present invention connects the high-temperature steam output pipeline of the black water flash evaporator to the hot-side input end of the generator of the absorption heat pump device, and the black water flash evaporator is equipped with a high-temperature condensate return pipeline connected to the hot-side output end of the generator. This allows the high-temperature steam generated by the black water flash evaporator to recover a portion of its heat after passing through the generator of the absorption heat pump device, and then return to the black water flash evaporator to participate in flash evaporation again. Furthermore, by connecting the low-temperature steam output pipeline of the black water flash evaporator to the hot-side input end of the evaporator of the absorption heat pump device, the low-temperature steam generated by flash evaporation heats the refrigerant water in the evaporator, while the medium-temperature steam generated by the black water flash evaporator can be supplied from the first steam external supply pipeline. The output is directly utilized by equipment outside the system. By connecting the black water output pipeline of the black water flash evaporator to the preheating device for the water to be heated, the grey water generated after flash evaporation of the black water flash evaporator is used to preheat the water to be heated. Then, the preheated water to be heated flows sequentially through the condenser and absorber of the absorption heat pump device to further heat the water to be heated through a reverse heating method. This creates a more reasonable temperature gradient, enables more efficient energy cascade utilization, significantly improves efficiency, and fully taps the potential of low-temperature heat sources such as low-temperature steam and grey water. This significantly enhances the waste heat recovery capacity of the system and increases the output rate of high-quality steam under the same heat input conditions. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the black water waste heat recovery system in this invention; Figure 2 This is a temperature-entropy curve of the solution and the water to be heated in this invention; Figure 3 This is a load distribution diagram of the absorption heat pump device in this invention; Figure 4 This is a trend diagram showing the effect of the generator's temperature in this invention; Figure 5 This is a trend diagram showing the influence of the condenser temperature in this invention; Figure 6 This is a trend diagram showing the influence of black water flow rate in this invention.

[0021] In the picture: 100. Black water flash evaporation device; 200. Absorption heat pump device; 300. Preheating device for water to be heated; 400. Steam generator for water to be heated; 1. High-pressure flash tank; 2. First mixer; 3. Low-pressure flash tank; 4. Second mixer; 5. Vacuum flash tank; 6. Generator; 7. Condenser; 8. Refrigerant water control valve; 9. Evaporator; 10. Absorber; 11. Solution pump; 12. Solution heat exchanger; 13. Solution control valve; 14. Flash tank for water to be heated; 15. Heat exchanger for water to be heated; 16. High-temperature steam output pipeline; 17. High-temperature condensate return pipeline; 18. First external steam supply pipeline; 19. Water to be heated input pipeline; 20. Low-temperature steam output pipeline; 21. Black water output pipeline; 22. Second external steam supply pipeline; 23. Dilute solution conveying pipeline; 24. Concentrated solution conveying pipeline; 25. Refrigerant water conveying pipeline; 26. Heating water regulating valve; 27. Low temperature condensate return pipeline; 28. Ejector; 29. ​​Solution circulation pump; 30. Refrigerant water circulation pump; 31. Refrigerant water circulation control valve; 32. Solution bypass; 33. Refrigerant water bypass. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Implementation Method 1

[0024] like Figure 1 As shown, this invention provides a blackwater waste heat recovery system, including a blackwater flash evaporation device 100, an absorption heat pump device 200, and a preheating device for the water to be heated 300. The absorption heat pump device 200 includes a generator 6, an absorber 10, a condenser 7, and an evaporator 9. The blackwater flash evaporation device 100 is equipped with a high-temperature steam output pipeline 16, a high-temperature condensate return pipeline 17, a first external steam supply pipeline 18, a low-temperature steam output pipeline 20, and a blackwater output pipeline 21. The input end of the high-temperature steam output pipeline 16, the output end of the high-temperature condensate return pipeline 17, and the first external steam supply pipeline 18... The input end and the output end of the low-temperature steam output pipeline 20 are arranged along the black water conveying direction of the black water flash evaporator 100; the cold side of the preheating device 300, the cold side of the condenser 7, and the cold side of the absorber 10 are connected along the hot water conveying direction; the output end of the black water output pipeline 21 is connected to the hot side input end of the preheating device 300; the output end of the high-temperature steam output pipeline 16 is connected to the hot side input end of the generator 6; the input end of the high-temperature condensate return pipeline 17 is connected to the hot side output end of the generator 6; and the output end of the low-temperature steam output pipeline 20 is connected to the cold side input end of the evaporator 9.

[0025] To better illustrate the transport paths of various fluids, Figure 1 In the diagram, the black arrow indicates the direction of black water transport, the red arrow indicates the direction of steam transport generated by black water flash evaporation, the green arrow indicates the direction of working fluid solution transport in the absorption heat pump device 200, the yellow arrow indicates the direction of refrigerant water transport in the absorption heat pump device 200, and the blue arrow indicates the direction of water to be heated.

[0026] The black water waste heat recovery system of the present invention connects the high-temperature steam output pipeline 16 of the black water flash evaporator 100 to the heat-side input terminal of the generator 6 of the absorption heat pump device 200, and the black water flash evaporator 100 is provided with a high-temperature condensate return pipeline 17 connected to the heat-side output terminal of the generator 6. This allows the high-temperature steam generated by the black water flash evaporator 100 to recover a portion of its heat after passing through the generator 6 of the absorption heat pump device 200, and then return to the black water flash evaporator 100 to participate in flash evaporation again. Furthermore, the low-temperature steam output pipeline 20 of the black water flash evaporator 100 is connected to the heat-side input terminal of the evaporator 9 of the absorption heat pump device 200. At the input end, the low-temperature steam generated by flash evaporation heats the refrigerant water in the evaporator 9, while the medium-temperature steam generated by the black water flash evaporator 100 can be output from the first steam external supply pipeline 18 and directly used by equipment outside the system. Furthermore, by connecting the black water output pipeline 21 of the black water flash evaporator 100 to the preheating device 300, the grey water generated after flash evaporation by the black water flash evaporator 100 preheats the water to be heated. The preheated water then flows sequentially through the condenser 7 and absorber 10 of the absorption heat pump device 200, achieving further heating of the water through a reverse heating method, thus combining... Figure 2 It is understood that the black water waste heat recovery system of the present invention constructs a more reasonable temperature gradient, which can achieve more efficient energy cascade utilization, significantly improve efficiency, and fully tap the potential of low-temperature heat sources such as low-temperature steam and ash water, thereby significantly enhancing the waste heat recovery capacity of the system, and increasing the output rate of high-quality steam under the same heat energy input conditions.

[0027] In addition, combined Figure 3 As shown, the heat load of the generator 6 of the absorption heat pump device 200 is 23.70kW, the heat load of the evaporator 9 is 17.24kW, the heat load of the absorber 10 is 22.70kW, and the heat load of the condenser 7 is 18.23kW. It can be seen that the ratio of the heat load of the absorber 10 to the heat load of the generator 6 is close to 1, and the heat release during the absorption process is sufficient and the energy utilization efficiency is high.

[0028] Combination Figure 4It can be seen that within the temperature range of 155℃ to 165℃, the system efficiency and heat pump performance parameters exhibit significant and regular variations. Specifically, the system efficiency continuously increases with the increase of the generator 6 temperature, while the heat pump performance parameters fluctuate slightly within a narrow range, maintaining overall high stability. When the generator 6 temperature is within the range of 155℃ to 165℃, the system efficiency can still reach a minimum of 1.3899 and a maximum of 1.4852. With each 1℃ increase in generator 6 temperature, the system efficiency shows a steady upward trend; the higher the temperature, the stronger the system's ability to convert and utilize heat energy. The heat pump efficiency can still reach a minimum of 99.96904% and a maximum of 99.96921%. Even under the condition of constant temperature variation in generator 6, the fluctuation range of heat pump efficiency is only 0.00017%. Therefore, the black water waste heat recovery system of this invention possesses superior thermal stability under different temperature conditions of generator 6, and can continuously maintain high-efficiency energy recovery performance. Similarly, combined with... Figure 5 and Figure 6 It can be seen that the black water waste heat recovery system of the present invention has excellent thermal stability under different temperature conditions of condenser 7 and different flow rates of black water, and can continuously maintain high-efficiency energy recovery performance.

[0029] Specifically, the high-temperature steam generated by the black water flash evaporator 100 is input into the generator 6 of the absorption heat pump device 200 via the high-temperature steam output pipeline 16, where the concentrated liquid in the generator 6 is heated, concentrated, and separated to produce refrigerant water vapor. The high-temperature steam is then recycled by the generator 6 and converted into high-temperature condensate, which is then returned to the black water flash evaporator 100 via the high-temperature condensate return pipeline 17. The low-temperature steam generated by the black water flash evaporator 100 is input into the evaporator 9 of the absorption heat pump device 200 via the low-temperature steam output pipeline 20, where the refrigerant water is heated. The medium-temperature steam generated by the black water flash evaporator 100 can be sent to equipment outside the system via the first steam external supply pipeline 18 for direct use. The high-temperature black water is converted into grey water (i.e., low-temperature black water) after flash evaporation by the black water flash evaporator 100, and sent to the preheating device 300 for preheating the water to be heated via the black water output pipeline 21.

[0030] like Figure 1 As shown, in the embodiment of the present invention, the black water flash evaporation device 100 is a three-stage flash evaporation device capable of performing three flash evaporations on black water along the black water conveying direction. The high-temperature steam is the steam generated in the first flash evaporation. The condensate returned through the high-temperature condensate return pipe 17 is mixed with the black water after the first flash evaporation and then subjected to a second flash evaporation. The medium-temperature steam is the steam generated in the second flash evaporation, the low-temperature steam is the steam generated in the third flash evaporation, and the ash water is the black water after the third flash evaporation.

[0031] Specifically, the black water flash evaporation device 100 includes a high-pressure flash tank 1, a low-pressure flash tank 3, and a vacuum flash tank 5 connected sequentially along its black water conveying direction. The steam output end of the high-pressure flash tank 1 is connected to the input end of the high-temperature steam output pipeline 16, the steam output end of the low-pressure flash tank 3 is connected to the input end of the first external steam supply pipeline 18, the liquid phase output end of the vacuum flash tank 5 is connected to the input end of the black water output pipeline 21, and the output end of the high-temperature condensate return pipeline 17 is connected between the high-pressure flash tank 1 and the low-pressure flash tank 3. Furthermore, to avoid the low temperature of the low-temperature steam affecting its reheating of the refrigerant water, the steam output end of the low-pressure flash tank 3 can also be connected to the vacuum flash tank 5 through a steam diversion pipeline to deliver a certain proportion of medium-temperature steam to the vacuum flash tank 5 as needed.

[0032] In this embodiment, the temperature of the high-temperature steam is 170℃~190℃; the temperature of the low-temperature steam is 45℃~90℃; the temperature of the medium-temperature steam is 120℃~150℃, which can be used as industrial steam for external supply; and the temperature of the black water is 35℃~50℃. The high-temperature steam, after recovering some heat through generator 6, is condensed into high-temperature condensate with a temperature of 130℃~140℃.

[0033] like Figure 1 As shown, the black water flash evaporation device 100 further includes a first mixer 2. The first mixer 2 is connected to the liquid phase output end of the high-pressure flash tank 1 and the liquid phase input end of the low-pressure flash tank 3, and is connected to the output end of the high-temperature condensate return pipeline 17. This allows the black water after the first flash evaporation in the high-pressure flash tank 1 and the condensate returned by the high-temperature condensate return pipeline 17 to be mixed evenly by the first mixer 2 and then flow into the low-pressure flash tank 3 for a second flash evaporation.

[0034] like Figure 1 As shown, in an embodiment of the present invention, the black water waste heat recovery system further includes a steam generator 400 for heating water. The input end of the steam generator 400 is connected to the cold side output end of the absorber 10. The steam generator 400 is provided with a second external steam supply pipeline 22, so that the steam generated by the evaporation of the heated water in the steam generator 400 is transported from the second external steam supply pipeline 22 to equipment outside the system for direct use.

[0035] Specifically, the steam generator 400 includes a flash evaporator 14 for the water to be heated, the steam output end of which is connected to the input end of the second external steam supply pipeline 22. The water to be heated, after being sequentially heated by the preheating device 300, condenser 7, and absorber 10, enters the flash evaporator 14 and flashes to generate steam at a certain pressure. In this embodiment, the temperature of the steam generated in the steam generator 400 is 120℃~130℃, and it can also be used as industrial steam for external supply. The preheating device 300 includes, but is not limited to, a heat exchanger 15 for the water to be heated.

[0036] like Figure 1 As shown in the embodiment of the present invention, the black water flash evaporation device 100 is further provided with a water input pipeline 19 to be heated. The output end of the water input pipeline 19 is located between the output end of the high-temperature condensate return pipeline 17 and the input end of the low-temperature steam output pipeline 20 in the black water conveying direction. The input end of the water input pipeline 19 is connected to the liquid phase output end of the steam generator 400 to be heated. By providing the water input pipeline 19, the unevaporated water in the steam generator 400 to be heated is transported to the black water flash evaporation device 100 to participate in flash evaporation together with the black water.

[0037] Specifically, the output end of the water to be heated input pipeline 19 is connected between the low-pressure flash tank 3 and the vacuum flash tank 5, allowing it to enter the vacuum flash tank 5 together with the black water after the second flash evaporation for a third flash evaporation; the input end of the water to be heated input pipeline 19 is connected to the liquid phase output end of the water to be heated. Furthermore, the black water flash evaporation device 100 also includes a second mixer 4, which is connected to the liquid phase output end of the low-pressure flash tank 3 and the liquid phase input end of the vacuum flash tank 5, and is also connected to the output end of the water to be heated input pipeline 19. This allows the black water after the second flash evaporation in the low-pressure flash tank 3 and the water to be heated output through the water to be heated input pipeline 19 to be mixed evenly by the second mixer 4 before flowing into the vacuum flash tank 5 for a third flash evaporation.

[0038] like Figure 1As shown, in the embodiment of the present invention, the generator 6 and the absorber 10 are connected to form a solution circulation loop through the dilute solution delivery pipeline 23 and the concentrated solution delivery pipeline 24. The generator 6 is connected to one end of the refrigerant water delivery pipeline 25 through the condenser 7, and the absorber 10 is connected to the other end of the refrigerant water delivery pipeline 25 through the evaporator 9. This allows the low-temperature dilute solution to be input into the generator 6 through the dilute solution delivery pipeline 23 to absorb the heat of the high-temperature steam generated by the black water flash evaporation device 100, thereby separating the refrigerant water vapor and forming a high-temperature concentrated solution. The refrigerant water vapor heats the water to be heated flowing through the condenser 7 and condenses it into refrigerant water. It is then transported to the evaporator 9 through the refrigerant water delivery pipeline 25 to exchange heat with the low-temperature steam generated by the black water flash evaporation device 100 and rise in temperature to form refrigerant water vapor. This refrigerant water vapor then enters the absorber 10 and is remixed with the high-temperature concentrated solution to further heat the water to be heated output from the condenser 7, thereby remixing it into a low-temperature dilute solution.

[0039] Furthermore, such as Figure 1 As shown, in order to optimize the temperature gradient between the high-temperature concentrated solution and the low-temperature dilute solution, the absorption heat pump device 200 also includes a solution heat exchanger 12, which is located in the concentrated solution delivery pipeline 24 and the dilute solution delivery pipeline 23 to exchange heat between the concentrated solution and the dilute solution.

[0040] The solution in the absorption heat pump device 200 may be, but is not limited to, a lithium bromide solution. The mass concentration of lithium bromide in the dilute solution is preferably 45% to 50%, and the mass concentration of lithium bromide in the concentrated solution is preferably 55% to 60%.

[0041] like Figure 1 As shown, the absorber 10 has a concentrated solution spray structure at its hot-side input end. This allows the high-temperature concentrated solution, after being input from the hot-side input end of the absorber 10, to be sprayed out from the concentrated solution spray structure to exchange heat with the water to be heated, thereby improving the heat exchange efficiency between the concentrated solution and the water to be heated within the absorber 10. Furthermore, to ensure the uniformity of the concentrated solution sprayed from the concentrated solution spray structure and further improve the heat exchange efficiency, a solution control valve 13 is provided in the concentrated solution delivery pipeline 24 between the absorber 10 and the solution heat exchanger 12. The solution control valve 13 directly or indirectly controls the pressure of the concentrated solution input into the absorber 10 through the concentrated solution delivery pipeline 24 to match the working pressure of the concentrated solution spray structure. Preferably, the solution control valve 13 is a throttle valve, capable of regulating the pressure and flow rate of the concentrated solution.

[0042] like Figure 1As shown, the cold-side input end of generator 6 is equipped with a dilute solution spray structure, which allows the low-temperature dilute solution, after being input from the cold-side input end of generator 6, to be sprayed out from the dilute solution spray structure to exchange heat with high-temperature steam, thereby improving the heat exchange efficiency between the dilute solution and high-temperature steam within generator 6. Furthermore, to ensure the uniformity of the dilute solution sprayed from the dilute solution spray structure and further improve the heat exchange efficiency, a solution pump 11 is installed in the dilute solution delivery pipeline 23 between absorber 10 and solution heat exchanger 12. The solution pump 11 pressurizes the dilute solution to match the working pressure of the dilute solution spray structure.

[0043] like Figure 1 As shown, the cold-side inlet of the evaporator 9 is equipped with a refrigerant water spray structure, allowing low-temperature refrigerant water to be sprayed out from the refrigerant water spray structure after entering from the cold-side inlet of the generator 6, thus exchanging heat with the low-temperature steam and improving the heat exchange efficiency between the refrigerant water and the low-temperature steam within the evaporator 9. Furthermore, a refrigerant water control valve 8 is provided on the refrigerant water delivery pipeline 25. The refrigerant water control valve 8 can directly or indirectly control the pressure of the refrigerant water entering the evaporator 9 through the refrigerant water delivery pipeline 25 to match the working pressure of the refrigerant water spray structure. Preferably, the refrigerant water control valve 8 is a throttling valve, capable of regulating the pressure and flow rate of the refrigerant water.

[0044] like Figure 1 As shown, the hot-side output end of the evaporator 9 is connected to the low-pressure flash tank 3 via a low-temperature condensate return pipe 27. This allows the low-temperature condensate formed by the cooling of the low-temperature steam in the evaporator 9 to return to the low-pressure flash tank 3 via the low-temperature condensate return pipe 27, which is beneficial for the full utilization of the low-temperature heat source. To ensure the smooth return of the low-temperature condensate, an ejector 28 is provided on the low-temperature condensate return pipe 27. The cold-side connection of the preheating water device 300 to the preheating water device 300 is equipped with a preheating water regulating valve 26, which can regulate the flow rate of the preheating water entering the preheating water device 300. This helps to improve the compatibility between the heat enhancement of the low-temperature heat source and the temperature decay characteristics of black water, so that high, medium, and low grade heat energy can be fully utilized, making the energy cascade utilization of the black water waste heat recovery system of the present invention more thorough and the loss lower.

[0045] like Figure 1As shown, the hot side of the absorber 10 is also connected to both ends of the solution bypass 32, and a solution circulation pump 29 is provided on the solution bypass 32. By turning on the solution circulation pump 29, a portion of the solution in the absorber 10 can circulate through the solution bypass 32, thereby improving the absorption capacity of the absorber 10. The cold side of the evaporator 9 is also connected to the refrigerant water delivery pipeline 25 through the refrigerant water bypass 33, and a refrigerant water circulation pump 30 is provided on the refrigerant water bypass 33. A refrigerant water circulation control valve 31 is provided at the connection between the refrigerant water delivery pipeline 25 and the refrigerant water bypass 33. By turning on the refrigerant water circulation control valve 31 and the refrigerant water circulation pump 30, a portion of the refrigerant water in the evaporator 9 can circulate through the refrigerant water bypass 33, thereby improving the evaporation capacity of the evaporator 9. In some embodiments of the present invention, the circulation process of the entire black water waste heat recovery system is as follows: I. Blackwater side (i.e., waste heat release flow): High-temperature black water (170℃~190℃, 0.8MPa~1.2MPa) enters the high-pressure flash tank 1, and flash evaporation generates high-temperature steam at 170℃~190℃, which is then transported to the generator 6 of the absorption heat pump device 200 via the high-temperature steam output pipeline 16. The liquid phase (160℃~180℃) after flashing in the high-pressure flash tank 1 is transported to the first mixer 2 and mixed with the high-temperature condensate (130℃~140℃) discharged from the generator 6 via the high-temperature condensate return pipeline 17 to form a mixed liquid at 140℃~160℃. The mixture enters the low-pressure flash tank 3, where flash evaporation generates medium-temperature steam at 120℃~150℃, which is then directly supplied to industrial steam via the first external steam supply pipeline 18; the liquid phase (110℃~140℃) after flash evaporation in the low-pressure flash tank 3 is then transported to the second mixer 4. The second mixer 4 receives the liquid phase (110℃~140℃) from the low-pressure flash tank 3 and mixes it with the unflashed liquid phase (120℃~130℃) discharged from the flash tank 14 of the water to be heated, which flows back through the water to be heated input pipeline 19, to form a mixed liquid at 120℃~130℃. The mixture enters the vacuum flash tank 5 and flashes at a vacuum of -0.08MPa to -0.09MPa to generate low-temperature steam at 45℃ to 90℃. The low-temperature steam is then delivered to the evaporator 9 of the absorption heat pump device 20 via the low-temperature steam output pipeline 20. The liquid phase (35℃~50℃) after flashing in the vacuum flash tank 5 is transported to the hot side of the preheating device 300 for hot water through the black water output pipeline 21. After releasing the residual heat, it is cooled to 60℃~70℃ and discharged in compliance with standards. In addition, when the low-temperature steam supply of the vacuum flash tank 5 is insufficient and affects the effect of the low-temperature steam being transported to the evaporator 9 through the low-temperature steam output pipeline 20 to reheat the refrigerant water, the medium-temperature steam of the low-temperature and low-pressure flash tank 3 can be supplemented to the vacuum flash tank 5 through the steam diversion pipeline (accounting for 20%-30%).

[0046] II. The side of the water to be heated (i.e., the waste heat absorption flow): The room temperature water to be heated (20℃~30℃) enters the cold side of the water preheating device 300 and exchanges heat with the liquid phase (35℃~50℃) discharged from the vacuum flash tank 5 on the hot side, preheating the water to be heated to 50℃~60℃. The preheated water to be heated (50℃~60℃) is sent to the cold side of the condenser 7 to exchange heat with the refrigerant water vapor at 150℃~170℃ output by the generator 6, raising the temperature of the water to be heated to 80℃~90℃. The water to be heated (80℃~90℃) discharged from the condenser 7 is transported to the cold side of the absorber 10, where it exchanges heat with the concentrated solution in the absorber 10 to absorb the heat released by the refrigerant water vapor, and the water to be heated is heated to 120℃~130℃. Furthermore, the water to be heated (120℃~130℃) discharged from the absorber 10 is transported to the water flash tank 14 to generate industrial steam at 120℃~130℃ under a flash pressure of 1.0MPa~1.2MPa, and then supplied externally through the second steam external supply pipeline 22; the unflashed liquid phase (120℃~130℃) in the water flash tank 14 is transported to the second mixer 4 through the water input pipeline 19, and mixed with the liquid phase discharged from the low-pressure flash tank 3 before entering the vacuum flash tank 5 to achieve secondary recovery of waste heat.

[0047] III. Working fluid side of the heat pump (i.e., working fluid solution, i.e., energy boosting flow)

[0048] The dilute lithium bromide solution (mass concentration of 45%~50%) is pressurized by the solution pump 11 and then transported to the cold side of the solution heat exchanger 12 to exchange heat with the concentrated lithium bromide solution (mass concentration of 55%~60%) on the hot side.

[0049] The heated dilute solution is transported to the cold side of generator 6, where it exchanges heat with the high-temperature steam (170℃~190℃) output from the high-pressure flash tank 1 on its hot side. The dilute solution is heated to 150℃~170℃ and separated into two parts: a concentrated solution with a mass concentration of 55%~60% and refrigerant water vapor at 150℃~170℃. Among them, refrigerant water vapor at 150℃~170℃ is transported to the hot side of condenser 7, where it exchanges heat with the water to be heated on the cold side and condenses into refrigerant water at 90℃~99℃; concentrated solution with a mass concentration of 55%~60% is transported to the hot side of solution heat exchanger 12 via concentrated solution transport pipeline 24, and the pressure is adjusted by solution control valve 13 (from 0.8MPa~1.0MPa to 0.02MPa~0.03MPa) and then transported to the hot side of absorber 10; The refrigerant water (90℃~99℃) output from the condenser 7 is depressurized to 0.02MPa~0.03MPa through the refrigerant water control valve 8, and then transported to the cold side of the evaporator 9 through the refrigerant water delivery pipeline 25. It exchanges heat with the low-temperature steam (45℃~90℃) output from the vacuum flash tank 5 on its hot side, and the refrigerant water is heated to 90℃~95℃ and vaporized into refrigerant water vapor. The refrigerant water vapor (90℃~95℃) delivered from the evaporator 9 is delivered to the hot side of the absorber 10, where it is absorbed by the concentrated solution (55%~60%). The released heat heats the water to be heated on the cold side of the absorber 10, while the concentrated solution is diluted into a dilute solution (45%~50%). The dilute solution (45%~50%) output from the absorber 10 flows back to the solution pump 11 through the dilute solution delivery pipeline 23, completing one cycle of the heat pump working fluid.

[0050] In addition, such as Figure 1 As shown, to better understand and implement the black water waste heat recovery system and method of the present invention, a specific embodiment is provided below: 1. Black water flash evaporation device 100: The high-pressure flash tank 1 receives industrial high-temperature and high-pressure black water at 170℃~190℃, and then flash-evaporates it to generate high-temperature steam at 170℃~190℃, thereby providing a driving heat source for the generator 6 of the absorption heat pump device 200; after flash evaporation, the black water at 160℃~180℃ is discharged and transported to the first mixer 2. The main technical parameters of the high-pressure flash tank 1 include: working pressure of 0.8MPa~1.2MPa; working temperature of 170℃~190℃; and processing flow rate of 20 m³ / h~30 m³ / h. The specific structure of the high-pressure flash tank 1 includes: a material of 316L stainless steel; a metal wire mesh demister installed below its steam output end to intercept liquid droplets entrained in the steam; the metal wire mesh of the demister has a mesh size of 0.5mm and three layers; a check valve is installed on the pipeline connected to the liquid output end of the high-pressure flash tank 1 to prevent backflow of the mixture; a pressure sensor and a temperature sensor are installed inside the high-pressure flash tank 1 to monitor the operating conditions in real time; the detection accuracy of the pressure sensor is ±0.01MPa; the detection accuracy of the temperature sensor is ±0.5℃. The first mixer 2 mixes the black water discharged from the high-pressure flash tank 1 with the condensate discharged from the generator 6 to form a temperature-stable mixture, which provides feed for the low-pressure flash tank 3, avoiding the impact of temperature fluctuations on flash evaporation efficiency. The main technical parameters of the first mixer 2 include: a mixing temperature of 140℃~160℃ with a temperature fluctuation of ±5℃; and a mixing pressure of 0.6MPa~0.9MPa. The specific structure of the first mixer 2 includes: a built-in honeycomb mixing core to enhance fluid turbulence and mixing uniformity; wherein the honeycomb pores of the honeycomb mixing core have a pore diameter of 10mm and a length of 300mm; and a flow regulating valve is installed on the pipeline connected to the input end of the first mixer 2 to match the flow rates of the liquid discharged from the high-pressure flash tank 1 and the condensate discharged from the generator 6.

[0051] The low-pressure flash tank 3 performs secondary flash evaporation on the mixed liquid discharged from the first mixer 2, producing low-pressure steam at 120℃~150℃ for direct industrial use; black water at 110℃~140℃ is discharged from the bottom and transported to the second mixer 4. The main technical parameters of the low-pressure flash tank 3 include: working pressure of 0.2 MPa~0.5 MPa; working temperature of 120℃~150℃; and steam output of 5t / h~8t / h. The specific structural design of the low-pressure flash tank 3 includes: a pressure regulating valve at the steam output end to control the steam output pressure; the steam output end of the low-pressure flash tank 3 is also connected to the vacuum flash tank 5 via a steam diversion bypass to transport excess steam to the vacuum flash tank 5, with the proportion of steam transported to the vacuum flash tank 5 being 20%-30%; a level gauge at the bottom of the low-pressure flash tank 3 to control the liquid level; the level gauge can be a magnetic float level gauge.

[0052] The second mixer 4 mixes the black water discharged from the low-pressure flash tank 3 with the unflashed water discharged from the hot water flash tank 14 to form a temperature-stable mixture, which provides feed for the vacuum flash tank 5 and avoids temperature fluctuations affecting flash evaporation efficiency. The main technical parameters of the second mixer 4 include: a mixing temperature of 120℃~130℃, with a temperature fluctuation of ±5℃. The specific structure of the second mixer 4 can be the same as that of the first mixer 2.

[0053] The vacuum flash tank 5 performs deep flash evaporation on the mixture discharged from the second mixer 4 to generate low-grade vacuum steam at 45℃~90℃, which provides a supplementary heat source for the evaporator 9 of the absorption heat pump device 200; the black water discharged after flash evaporation at 35℃~50℃ is transported to the preheating device 300 for the water to be heated.

[0054] II. Absorption heat pump unit 200: Using a lithium bromide solution with a mass concentration of 50%~60% as the working fluid, the preheated water to be heated is heated by a reverse heating method from condenser 7 to absorber 10.

[0055] Generator 6 has a shell-and-tube structure with a shell diameter of 800 mm and a tube length of 3000 mm. The shell side contains a cold-side fluid, namely a dilute lithium bromide solution with a mass concentration of 45%-50%. The tube side contains a hot-side fluid, namely high-temperature steam output from the high-pressure flash tank 1 at a pressure of 0.08-0.2 MPa and a temperature of 130-140℃. High-frequency welded fins are provided on the outer side of the tube side to improve heat exchange efficiency. The generator 6 produces refrigerant steam at a temperature of 150℃-170℃ and a concentrated solution with a mass concentration of 55%-60% at a temperature of 150℃-170℃. A pressure transmitter, temperature sensor, and steam control valve are installed at the inlet of the tube side, i.e., the hot-side input end, while a concentration sensor with an accuracy of ±0.5% is installed at the outlet of the shell side, i.e., the cold-side output end. The control process of generator 6 includes: real-time acquisition of steam pressure and temperature through the pressure transmitter and temperature sensor and feedback to the PLC system; when the steam pressure fluctuation exceeds ±0.02MPa or the temperature fluctuation exceeds ±5℃, the opening of the steam control valve is adjusted in conjunction with the adjustment of the solution pump 11 to regulate the flow rate of the dilute solution, so as to maintain a stable boiling state of the internal dilute solution; the concentration sensor monitors the concentration of the concentrated solution in real time, and the input steam quantity is corrected based on the concentration of the concentrated solution through a PID algorithm to ensure that the concentration deviation is ≤±1%.

[0056] The condenser 7 has a shell-and-tube structure with a shell diameter of 600 mm and a tube length of 2500 mm. The shell side contains the hot-side fluid, which is refrigerant water vapor separated from the generator 6 at a temperature of 150℃-170℃. The tube side contains preheated water to be heated at a temperature of 80℃-90℃. A steam regulating valve is provided at the shell-side inlet, i.e., the hot-side input end, to control the temperature rise of the water to be heated to 80℃-90℃ after heat exchange with the refrigerant water vapor. The refrigerant water vapor is cooled and condensed into refrigerant water at 90℃-99℃ and discharged from the shell-side outlet, i.e., the hot-side output end. Then, it is depressurized to 0.02 MPa-0.03 MPa by the refrigerant water control valve 8. A pressure sensor and a steam regulating valve are installed at the shell-side inlet, a temperature transmitter is installed at the tube-side outlet, and a temperature sensor is installed at the refrigerant water outlet. The control process of condenser 7 includes: the PLC system sets the target temperature of the water to be heated after it is output from the tube-side outlet to 80℃-90℃, and dynamically adjusts the opening of the steam regulating valve at the shell-side inlet according to the tube-side outlet temperature monitored by the temperature transmitter; when the temperature deviation exceeds ±2℃, the opening step of the steam regulating valve is adjusted in a step of 0.5% / s; in addition, the temperature sensor monitors the output temperature of the refrigerant water in real time, providing feedback signals for the subsequent adjustment of the refrigerant water control valve 8.

[0057] Evaporator 9 is a shell-and-tube structure with a shell diameter of 500 mm and a tube length of 2000 mm. The shell side contains the cold-side fluid, i.e., refrigerant water at a temperature of 90℃-95℃ after pressure reduction. The tube side contains the hot-side fluid, i.e., low-temperature steam output from vacuum flash tank 5 at a temperature of 45℃-90℃ and a pressure of -0.08~-0.09 MPa. Multiple baffles with a spacing of 120 mm are installed on the inner side of the tube side to extend the residence time of the steam to 15 seconds. The refrigerant water vapor at a temperature of 90℃-95℃ produced at the shell-side outlet of evaporator 9 is delivered to absorber 10. A flow sensor and a vacuum pressure transmitter are installed at the tube-side inlet, i.e., the hot-side input end. A temperature field distribution sensor is installed inside the shell side, with multiple temperature measurement points spaced 50 mm apart. The control process of evaporator 9 includes: real-time monitoring of the steam flow and pressure in the input tube side through flow sensors and vacuum pressure transmitters; automatic activation of the steam disturbance device in the tube side when the steam temperature change exceeds 5℃; and adjustment of the opening of the regulating valve on the steam distribution pipeline connected to the vacuum flash tank 5 in conjunction with the temperature feedback of the refrigerant water vapor monitored by the temperature field distribution sensor in the shell side, to ensure the stability of the heat load in evaporator 9 and make the temperature fluctuation of the refrigerant water vapor ≤±3℃.

[0058] The absorber 10 has a shell-and-tube structure with a shell diameter of 700 mm and a tube length of 3000 mm. The concentrated solution spray structure is a porous spray plate with spray holes of 2.5 mm in diameter and 12 mm in spacing. The shell side contains the hot-side fluid, which is a concentrated solution with a mass concentration of 55%-60% and refrigerant water vapor. The tube side contains the cold-side fluid, which is the water to be heated to 80℃-90℃ after being heated by the condenser 7. A pressure sensor is installed at the shell-side inlet (cold-side input), a temperature transmitter is installed at the tube-side outlet (cold-side input), and a dilute solution concentration sensor is installed at the shell-side outlet (hot-side output). The control process of the absorber 10 includes: heating the water to be heated to 120℃-130℃ by adjusting the spray volume of the concentrated solution; the control of the absorber 10 includes: when the output temperature of the water to be heated detected by the temperature transmitter deviates from the target range of ±2℃, a dual regulation mechanism is triggered, that is, the circulation volume of the dilute solution is adjusted by the frequency conversion of the solution pump 11, thereby changing the spray volume of the concentrated solution, and simultaneously adjusting the supply of low-temperature steam to the evaporator 9; the dilute concentration solution sensor monitors the concentration of the regenerated dilute solution in real time, and when the concentration deviation exceeds ±1%, the steam volume of the high-temperature steam input into the generator 6 is automatically corrected to form a concentration closed-loop control; the pressure sensor at the shell-side inlet monitors the input pressure of the concentrated solution, and adjusts the solution control valve 13 according to the input pressure to ensure that the spray pressure of the spray structure is stable at 0.05MPa-0.06MPa and the spray coverage is ≥98%.

[0059] Solution pump 11 is a variable frequency centrifugal pump, and an electromagnetic flow meter is installed at the outlet. The control process of solution pump 11 includes: the electromagnetic flow meter monitors the fluid of dilute solution in real time and feeds it back to the PLC system; the frequency of solution pump 11 is dynamically adjusted through PID algorithm to achieve precise matching between the flow rate of dilute solution and the heat load of generator 6; combined with the concentration and temperature of dilute solution, the set value of dilute solution flow rate is automatically corrected to ensure stable solution circulation.

[0060] The solution heat exchanger is a plate heat exchanger with counter-current heat exchange. The cold-side fluid is a dilute solution, and the hot-side fluid is a concentrated solution. After heat exchange within the heat exchanger, the dilute solution heats up by 30℃-40℃, while the concentrated solution cools down by 130℃-140℃. Temperature and pressure sensors are installed at the cold-side input and output ends of the solution heat exchanger, respectively. The control process of the solution heat exchanger includes: real-time monitoring of the dilute solution temperature before and after heat exchange using the temperature sensors at the cold-side input and output ends; then, combining this with the inlet and outlet temperature data of the concentrated solution, adjusting the flow rate of solution pump 11 to ensure that the output temperature fluctuation of the dilute solution is ≤±3℃; and monitoring the pressure using the pressure sensors at the cold-side input and output ends. When the pressure difference exceeds 0.3MPa, an automatic cleaning warning signal is issued.

[0061] The solution control valve 13 is a needle-type throttle valve that can reduce the pressure of the concentrated solution from 0.8MPa-1.0MPa to 0.02MPa-0.03MPa to match the working pressure of the absorber 10. The control process of the solution control valve 13 includes: dynamically adjusting the opening of the solution control valve 13 according to the coupling relationship between the shell-side pressure of the absorber 10 and the flow rate of the concentrated solution through a control algorithm; and automatically correcting the opening of the valve solution control valve 13 based on the temperature and concentration of the concentrated solution to avoid uneven spraying caused by pressure fluctuations.

[0062] III. Preheating device for water to be heated 300: The preheating device 300 for the water to be heated is a plate heat exchanger, with hemispherical turbulence protrusions on the hot side channel. Ash water at 45℃-90℃ discharged from the vacuum flash tank 5 enters the hot side channel of the preheating device 300, while fresh water at 20℃-30℃ enters the cold side channel. After heat exchange, the water is preheated to 50℃-60℃ and then transported to the tube side of the condenser 7. The black water is cooled to 60℃-70℃ to meet discharge standards. Temperature and flow sensors are installed at the inlet and outlet of both the hot and cold sides of the preheating device 300, and a water quality monitoring sensor is also installed at the hot side outlet. The control process of the preheating device 300 for hot water includes: temperature and flow sensors at the inlet and outlet of the hot and cold sides monitor the inlet and outlet temperatures and flow rates of the hot water and black water in real time; then, the waste heat recovery efficiency is calculated in real time based on the inlet and outlet temperatures and flow rates; when the waste heat recovery efficiency is lower than 85%, the flow rate of the hot water or the flow rate of the black water is automatically adjusted; and the water quality of the black water is monitored in real time by a water quality monitoring sensor to ensure that the discharge meets the standards.

[0063] IV. Steam generator 400 to be heated: The working pressure of the flash evaporator 14 of the steam generator 400 is 1.0 MPa - 1.2 MPa, the working temperature is 180℃ - 190℃, and the material is 316L stainless steel. The flash evaporator 14 is equipped with a PTFE microporous filter membrane at the steam output end to remove trace impurities such as salts and metal ions from the steam. The water to be heated after being heated by the absorber 10 has a temperature of 120℃-130℃. It enters the flash tank 14 and flashes under a pressure of 1.0 MPa-1.2 MPa to generate industrial steam with a pressure of 1.0 MPa and a temperature of 120℃-130℃. The steam is output from the steam output end to the second steam external supply pipeline 22. The water to be heated at 120℃-130℃ that has not been flashed is discharged from the liquid phase output end at the bottom and input into the second mixer 4 through the water input pipeline 19. It is then combined with the black water discharged from the low-pressure flash tank 3 and transported to the vacuum flash tank 5 for flashing to achieve secondary recovery of waste heat. The flash evaporator 14 for heated water is equipped with a pressure transmitter and a level sensor. A flow sensor and a purity detector are installed at the steam output end of the flash evaporator 14. Regulating valves are installed at the input, steam output, and liquid output ends of the flash evaporator 14. The control process of the flash evaporator 14 includes: monitoring the pressure and liquid level within the flash evaporator 14 via the pressure transmitter and level sensor and feeding this information back to the PLC system; adjusting the opening of the regulating valves at the input, steam output, and liquid output ends of the flash evaporator 14 via the PLC system to maintain a stable pressure within the flash evaporator 14 at 1.0MPa-1.2MPa and a liquid level controlled within the range of 30%-70%; automatically adjusting the input flow and pressure parameters of the heated water when the purity of the output steam is lower than 99.99% or when the steam output flow rate fluctuates by more than ±5%, ensuring stable steam quality.

[0064] V. The black water waste heat recovery system of this embodiment can ultimately output industrial steam with a temperature higher than ≥120℃, and the temperature fluctuation is within ±2℃, which meets the process requirements for medium and high pressure steam in coal chemical process; and the COP (coefficient of performance) of absorption heat pump device 200 reaches 99.97%, and the overall efficiency of the entire black water waste heat recovery system is 1.43: the temperature of the water to be heated can be raised to 130℃ through the reverse heating method from condenser 7 to absorber 10.

[0065] Implementation Method 2

[0066] This invention also provides a method for recovering waste heat from black water, comprising the following steps: Black water side start-up: High-temperature black water is transported to the black water flash evaporation device for flash evaporation. First, the generated high-temperature steam is transported to generator 6. Then, after the low-temperature steam generated by the black water flash evaporation device reaches its preset temperature, the low-temperature steam is transported to the hot side of the evaporator. Finally, the flash-evaporated low-temperature black water is transported to the hot side of the preheating device for the water to be heated.

[0067] Specifically, black water at 170℃~190℃ is input into the high-pressure flash tank 1, and the input flow rate of the black water is gradually increased from 10m³ / h to 20m³ / h~30m³ / h; when the flash pressure of the high-pressure flash tank 1 reaches 0.8MPa, the valve on the high-temperature steam output pipeline 16 is opened to supply high-temperature steam to the generator 6; when the pressure stabilizes at 1.0MPa, the liquid phase outlet valve of the high-pressure flash tank 1 is opened to supply liquid phase at 160℃~180℃ to the first mixer 2; the flow regulating valve of the first mixer 2 is started, and when the temperature of the mixed liquid stabilizes at 140℃~160℃, the outlet valve of the first mixer 2 is opened to supply the mixed liquid to the low-pressure flash tank 3; when the flash pressure of the low-pressure flash tank 3 reaches 0.2MPa... When the vacuum flash tank 5 is activated, the variable frequency vacuum pump (initial frequency 40Hz) is started to pump the vacuum to -0.085MPa; when the pressure of the low-pressure flash tank 3 stabilizes at 0.3MPa, the liquid phase outlet valve of the low-pressure flash tank 3 is opened to deliver liquid phase at 110℃~140℃ to the second mixer 4; when the temperature of the mixture in the second mixer 4 stabilizes at 120℃~130℃, the outlet valve of the second mixer 4 is opened to deliver the mixture to the vacuum flash tank 5; when the vacuum flash tank 5 generates low-temperature steam at 45℃~90℃, the valve on the low-temperature steam output pipeline 20 is opened to deliver low-temperature steam to the evaporator 9.

[0068] Heat pump start-up: The dilute solution is delivered to the cold side of generator 6; when the temperature of the dilute solution in generator 6 rises to its preset temperature, the refrigerant water vapor in generator 6 is delivered to the hot side of condenser 7; when the hot side of condenser 7 produces refrigerant water at the preset temperature, the refrigerant water is delivered to the cold side of evaporator 9; until the refrigerant water exchanges heat with low-temperature steam to form refrigerant water vapor at the preset temperature, the refrigerant water vapor is delivered to the hot side of absorber 10; the concentrated lithium bromide solution produced on the cold side of generator 6 is delivered to the hot side of absorber 10.

[0069] Specifically, the solution pump 11 is started at an initial frequency of 30Hz, delivering a 45%~50% concentration dilute lithium bromide solution to the solution heat exchanger 12, and then into the cold side of the generator 6. When the temperature of the dilute solution in the generator 6 rises to 150℃, the inlet valve for refrigerant vapor in the condenser 7 is opened, allowing refrigerant vapor at 150℃~170℃ to enter the hot side of the condenser 7. When refrigerant water at 90℃~99℃ is generated on the hot side of the condenser 7, the refrigerant water control valve 8 is opened (initial opening 30%), supplying refrigerant water to the cold side of the generator 6. Refrigerant water is supplied to the cold side of evaporator 9. When the refrigerant water on the cold side of evaporator 9 absorbs heat from low-temperature steam and vaporizes into refrigerant water vapor at 90℃~95℃, the refrigerant water vapor outlet valve of evaporator 9 is opened to supply refrigerant water vapor to the hot side of absorber 10. The opening degree of solution control valve 13 is adjusted (initially 50%) to ensure that the concentrated solution (55%~60%) is evenly sprayed to the shell side of absorber 10, ensuring that the spray pressure is stable at 0.05MPa~0.06MPa and the spray coverage is ≥98%.

[0070] Start-up of the water to be heated: The water to be heated is input into the cold side of the water preheating device 300 to exchange heat with the low-temperature black water; until the water to be heated in the water preheating device 300 reaches the preset temperature, the preheated water to be heated is sent to the cold side of the condenser 7 to exchange heat with the refrigerant steam; until the water to be heated in the condenser 7 reaches the preset temperature, the water to be heated is sent to the cold side of the absorber 10; until the water to be heated in the absorber 10 reaches the preset temperature.

[0071] Specifically, open the inlet valve of the ambient temperature water to be heated, and gradually increase the flow rate from 5 m³ / h to 15 m³ / h~20 m³ / h, sending it to the cold side of the water preheating device 300; when the temperature of the water to be heated on the cold side of the water preheating device 300 rises to 50℃~60℃, open the outlet valve of the cold side of the water preheating device 300 to supply water to the cold side of the condenser 7; when the temperature of the water to be heated on the cold side of the condenser 7 rises to 80℃~90℃, open the outlet valve of the cold side of the condenser 7 to supply water to the cold side of the absorber 10; when the temperature of the water to be heated on the cold side of the absorber 10 rises to 120℃~130℃, open the outlet valve of the cold side of the absorber 10 to supply water to the flash tank 14; when the flash pressure of the flash tank 14 rises to 1.0 MPa, open the second external steam supply pipeline 22. The valve on the top supplies steam to the outside; when the liquid level in the flash tank 14 of the water to be heated rises to 30%, the liquid phase outlet valve of the flash tank 14 of the water to be heated is opened to deliver the unflashed liquid phase to the second mixer 4.

[0072] The black water waste heat recovery system has entered a stable operation phase.

[0073] Furthermore, in an embodiment of the present invention, the operation of the blackwater waste heat recovery system also includes adjusting the blackwater waste heat recovery system during the stable operation phase: Monitor the output parameters of the external heat source supplied by the blackwater waste heat recovery system. Based on the output parameters of the external heat source, analyze and determine the real-time load of the external heat source; The black water waste heat recovery system is adjusted according to the real-time load and load demand of the external heat source under different load conditions.

[0074] The adjustment of the black water waste heat recovery system includes, but is not limited to, adjusting the black water input, black water output, high-temperature steam output, low-temperature steam output, and flash pressure of the black water flash evaporator 100. It may also include the steam diversion flow rate of the external steam supplied by the first external steam supply pipeline 18 of the black water flash evaporator 100 to the vacuum flash tank 5; it may also include the flow rate of concentrated solution and dilute solution between the generator 6 and absorber 10 of the absorption heat pump device 200, and the flow rate of refrigerant water between the condenser 7 and evaporator 9; it may also include the input of the water to be heated in the preheating device 300; and it may also include the flash pressure of the water flash tank 14 and the output of the external steam supplied by the second external steam supply pipeline 22.

[0075] In some embodiments of the present invention, the external heat source includes externally supplied steam via the first external steam supply pipeline 18. In other embodiments of the present invention, the external heat source further includes externally supplied steam via the second external steam supply pipeline 22. In still other embodiments of the present invention, the water to be heated, after being heated by the absorber 10, can be supplied directly as externally supplied hot water without entering the water to be heated steam generator 400; therefore, the external heat source may also include externally supplied hot water.

[0076] The output parameters of the external heat source include its flow rate and pressure. Based on the flow rate and pressure of the external heat source, the real-time load of the external heat source, i.e., its flow rate (mass flow rate), can be analyzed and calculated. The specific enthalpy at the corresponding pressure. The load demand of the external heat source is the flow rate and pressure of the external heat source that needs to be supplied to the external equipment. The load demand of the external heat source is then analyzed and calculated in the same way.

[0077] Based on the real-time load and load demand of the external heat source, the black water waste heat recovery system is adjusted according to the load conditions, including the following steps: Based on the ratio between the real-time load of the external heat source and the load demand, the current operating condition of the black water waste heat recovery system is analyzed as normal load condition, load surge condition, or load drop condition. For example, in this embodiment, if the real-time load is 80% to 100% of the load demand, the current operating condition is normal load condition; if the increase in load demand compared to the real-time load is greater than or equal to 30%, the current operating condition is load surge condition; if the decrease in load demand compared to the real-time load is greater than or equal to 50%, the current operating condition is load drop condition. If the current operating condition is under normal load, the adjustment of the black water waste heat recovery system includes the following steps: adjusting the flash pressure of the black water flash evaporator 100 according to the input of black water into the black water flash evaporator 100 and the output of external steam from the first external steam supply pipeline 18; adjusting the input of high-temperature steam and the circulation rate of the working fluid solution of the absorption heat pump device 200 according to the concentration of the working fluid solution; adjusting the delivery rate of the concentrated and dilute solutions of the absorption heat pump device 200 according to the temperature difference between the concentrated and dilute solutions; and adjusting the input of the water to be heated according to the temperature of the water to be heated after preheating in the water preheating device 300.

[0078] In this embodiment, under normal load conditions, on the black water side: the flash pressure of the high-pressure flash tank 1 is maintained at 1.0MPa~1.1MPa, and the input flow rate of black water is 20m³ / h~30m³ / h; the flash pressure of the low-pressure flash tank 3 is 0.3MPa~0.4MPa, and the output flow rate of the external steam supplied by the first external steam supply pipeline 18 is 5t / h~8t / h; the vacuum degree of the vacuum flash tank 5 is -0.085MPa~-0.09MPa; on the heat pump side: the concentration of the concentrated solution is monitored by the concentration sensor of the generator 6, and if it deviates from the concentration of the concentrated solution... 55%~60% (deviation ±1%), adjust the valve opening on the high-temperature steam output pipeline 16 (step 0.5% / s), and synchronously adjust the frequency of the solution pump 11 (±1Hz) to maintain a stable concentration; maintain the outlet temperature of the hot side of the solution heat exchanger 12 (i.e., the temperature of the output concentrated solution) at 30℃~40℃ and the outlet temperature of the cold side (i.e., the temperature of the output dilute solution) at 75℃~90℃. If the temperature difference deviates, adjust the flow rate of the dilute solution by adjusting the solution pump 11; on the side of the water to be heated: maintain the outlet temperature of the cold side of the preheating device 300 at 50℃~60℃. If it is lower than 50℃, reduce the opening of the inlet valve of the water to be heated to reduce the flow rate of the water to be heated by 2m³ / h; in addition, the steam purity of the flash tank 14 of the water to be heated is maintained at ≥99.99% through the PTFE microporous filter membrane. If the purity is insufficient, fine-tune the flash pressure of the flash tank 14 of the water to be heated, such as increasing it by 0.05MPa.

[0079] If the current operating condition is a sudden increase in load, the adjustment of the black water waste heat recovery system includes the following steps: increasing the black water input of the black water flash evaporator 100 and increasing the flash pressure of the black water flash evaporator 100, as well as increasing the output of low-temperature steam; increasing the flow rate of concentrated solution between generator 6 and absorber 10 and increasing the flow rate of refrigerant water between condenser 7 and evaporator 9; increasing the input of water to be heated; in addition, the flash pressure of the water to be heated flash tank 14 can be increased to increase the output of external steam from the second external steam supply pipeline 22.

[0080] In this embodiment, under a sudden load increase, on the black water side: the inlet valve of the high-pressure flash tank 1 is opened, increasing the flow rate from 25 m³ / h to 30 m³ / h and the pressure from 1.0 MPa to 1.1 MPa; the steam diversion valve from the low-pressure flash tank 3 to the vacuum flash tank 5 is opened (opening degree 20%~30%) to supplement low-temperature steam; on the heat pump side: the frequency of the solution pump 11 is increased from 30 Hz to 40 Hz, and the opening degree of the solution control valve 13 is increased from 50% to 70% to increase the concentrated solution spraying volume; the opening degree of the refrigerant water control valve 8 is opened (+10%) to increase the refrigerant water circulation volume; on the hot water side: the opening degree of the hot water inlet valve is increased, increasing the flow rate from 20 m³ / h to 25 m³ / h to ensure that the cold side water volume of the absorber 10 matches the heat load; the pressure of the hot water flash tank 14 is increased from 1.1 MPa to 1.2 MPa to increase steam production.

[0081] If the current operating condition is a sudden load drop, the adjustment of the black water waste heat recovery system includes the following steps: reducing the input of black water to the black water flash evaporator 100 and reducing the flash pressure of the water flash evaporator; reducing the circulation volume of the working solution; reducing the input of the water to be heated; in addition, it also includes reducing the frequency of the vacuum pump of the vacuum flash tank 5 to maintain the flash pressure (i.e., its vacuum degree) of the vacuum flash tank 5, avoiding excessive vacuuming and increasing energy consumption; it also includes reducing the flash pressure of the water to be heated flash tank 14 to reduce the output of the external steam supplied by the second external steam supply pipeline 22.

[0082] In this embodiment, under a sudden load drop, on the black water side: the inlet valve of the high-pressure flash tank 1 is closed, the flow rate decreases from 25 m³ / h to 15 m³ / h, and the pressure decreases from 1.0 MPa to 0.8 MPa; the pressure of the low-pressure flash tank 3 decreases from 0.3 MPa to 0.2 MPa, and the steam diversion valve is closed; on the heat pump side: the frequency of the solution pump 11 decreases from 30 Hz to 25 Hz, and the opening of the solution control valve 13 decreases from 50% to 30%; the frequency of the variable frequency vacuum pump decreases from 40 Hz to 30 Hz, and the vacuum degree of the vacuum flash tank 5 is maintained at -0.08 MPa; on the hot water side: the opening of the hot water inlet valve is reduced, and the flow rate decreases from 20 m³ / h to 10 m³ / h; the pressure of the hot water flash tank 14 decreases from 1.1 MPa to 1.0 MPa, and the liquid level is controlled at 30%~50%.

[0083] In addition, pre-boot preparations should be performed before the system starts, including the following steps: Equipment Inspection: Check the door seals of high-pressure flash tank 1, low-pressure flash tank 3, and vacuum flash tank 5, as well as the sealing of generator 6 and condenser 7, to ensure there are no leaks; check the on / off status of valves on each pipeline (such as valves on high-temperature steam output pipeline 16 and valves on high-temperature condensate return pipeline 17) to ensure they are initially closed; and check the response status of actuators, such as solution pump 11, variable frequency vacuum pump, and each electrically controlled valve, to ensure they operate normally. Working fluid preparation: Inject a 45%~50% lithium bromide dilute solution into absorber 10, with the liquid level reaching 1 / 2 of the shell side of absorber 10 (which can be monitored by a magnetic float level gauge); Inject deionized water into refrigerant water delivery line 25, open the vent valve to purge air bubbles from the line, and then close it. Parameter preset: Set the target parameters for each device. For example, in some embodiments, the flash pressure of the high-pressure flash tank 1 is 1.0 MPa and the temperature is 180°C; the flash pressure of the low-pressure flash tank 3 is 0.3 MPa and the temperature is 130°C; the vacuum degree of the vacuum flash tank 5 is -0.085 MPa; and the flash pressure of the water to be heated flash tank 14 is 1.1 MPa and the liquid level is 30%-70%. Sensor calibration: Calibrate each sensor. In some embodiments, the pressure sensor of the high-pressure flash tank 1 is calibrated to ±0.01 MPa, the concentration sensor of the generator 6 is calibrated to ±0.5%, and the temperature sensor of the preheating device 300 for the water to be heated is calibrated to ±0.2°C to ensure accurate data acquisition.

[0084] After completing the waste heat recovery of the black water, shutdown and maintenance are performed, including the following steps: Reduce load: First, close the inlet valve of the water to be heated and gradually reduce the input flow rate of the water to be heated from 15 m³ / h to 5 m³ / h; then close the inlet valve of the high-temperature black water and gradually reduce the input flow rate of the black water from 20 m³ / h to 10 m³ / h; finally, close the valves of the first external steam supply pipeline 18 and the second external steam supply pipeline 22 to stop supplying steam to the outside. Equipment shutdown: Close refrigerant water control valve 8 to stop refrigerant water circulation; stop solution pump 11 and recover the dilute solution (45%~50%) in absorber 10 to the storage tank (if the concentration is lower than 45%, replenish the concentrated solution to 45%); stop the variable frequency vacuum pump of vacuum flash tank 5 and break the vacuum of vacuum flash tank 5 (introduce nitrogen). Equipment maintenance: For the preheating device 300 for hot water: if the pressure difference between the hot and cold sides exceeds 0.3MPa, disassemble and clean the hemispherical turbulence protrusions in the hot side channel and remove the dirt; for the high-pressure flash tank 1: check the metal wire mesh demister (3 layers, 0.5mm aperture). If more than 5% of the liquid droplets are trapped, replace the wire mesh. Sensor calibration: Recalibrate the concentration sensor of generator 6 and the temperature transmitter of absorber 10 to ensure that the accuracy meets the requirements (concentration ±0.5%, temperature ±0.2℃). System evacuation: Open the drain valves of each device to drain the residual liquid in the black water flash evaporator 100 and the steam generator 400; close all valves and ensure the equipment is protected against moisture and dust.

[0085] The above descriptions are merely a few embodiments of the present invention. Those skilled in the art can make various modifications or variations to the embodiments of the present invention based on the content disclosed in the application documents without departing from the spirit and scope of the present invention.

Claims

1. A black water waste heat recovery system, characterized in that, It includes a black water flash evaporation device, an absorption heat pump device, and a preheating device for the water to be heated. The absorption heat pump device includes a generator, an absorber, a condenser, and an evaporator. The black water flash evaporation device is equipped with a high-temperature steam output pipeline, a high-temperature condensate return pipeline, a first external steam supply pipeline, a low-temperature steam output pipeline, and a black water output pipeline. The input end of the high-temperature steam output pipeline, the output end of the high-temperature condensate return pipeline, the input end of the first external steam supply pipeline, and the input end of the low-temperature steam output pipeline are arranged along the black water conveying direction of the black water flash evaporation device. The cold side of the preheating device for the water to be heated, the cold side of the condenser, and the cold side of the absorber are connected along the direction of water delivery for the water to be heated, and the output end of the black water output pipeline is connected to the input end of the hot side of the preheating device for the water to be heated. The output end of the high-temperature steam output pipeline is connected to the hot-side input end of the generator, the input end of the high-temperature condensate return pipeline is connected to the hot-side output end of the generator, and the output end of the low-temperature steam output pipeline is connected to the hot-side input end of the evaporator.

2. The black water waste heat recovery system as described in claim 1, characterized in that, The black water waste heat recovery system also includes a steam generator to be heated, the input end of which is connected to the cold side output end of the absorber, and the steam generator to be heated is provided with a second external steam supply pipeline.

3. The black water waste heat recovery system as described in claim 2, characterized in that, The steam generator for heating water includes a flash tank for heating water, and the steam output end of the flash tank for heating water is connected to the input end of the second external steam supply pipeline.

4. The black water waste heat recovery system as described in claim 2, characterized in that, The black water flash evaporation device is also provided with a water input pipeline to be heated. The output end of the water input pipeline to be heated is located between the output end of the high-temperature condensate return pipeline and the input end of the low-temperature steam output pipeline in the direction of black water transportation. The input end of the water input pipeline to be heated is connected to the liquid phase output end of the steam generator to be heated.

5. The black water waste heat recovery system as described in claim 4, characterized in that, The black water flash evaporation device includes a high-pressure flash tank, a low-pressure flash tank, and a vacuum flash tank connected sequentially along its black water conveyance direction. The steam output end of the high-pressure flash tank is connected to the input end of the high-temperature steam output pipeline. The steam output end of the low-pressure flash tank is connected to the input end of the first external steam supply pipeline. The steam output end of the vacuum flash tank is connected to the input end of the low-temperature steam output pipeline. The liquid phase output end of the vacuum flash tank is connected to the black water output pipeline. The output end of the high-temperature condensate return pipeline is connected between the high-pressure flash tank and the low-pressure flash tank. The output end of the water to be heated input pipeline is connected between the low-pressure flash tank and the vacuum flash tank.

6. The black water waste heat recovery system as described in claim 5, characterized in that, The black water flash evaporation device further includes a first mixer and a second mixer. The first mixer is connected to the liquid phase output end of the high-pressure flash tank and the liquid phase input end of the low-pressure flash tank, and is also connected to the output end of the high-temperature condensate return pipeline. The second mixer is connected to the liquid phase output end of the low-pressure flash tank and the liquid phase input end of the vacuum flash tank, and is also connected to the output end of the water to be heated input pipeline.

7. The black water waste heat recovery system as described in claim 1, characterized in that, The generator and the absorber are connected to form a solution circulation loop through a dilute solution delivery pipeline and a concentrated solution delivery pipeline. The generator is connected to one end of the refrigerant water delivery pipeline through the condenser, and the absorber is connected to the other end of the refrigerant water delivery pipeline through the evaporator. The absorption heat pump device further includes a solution heat exchanger, which is located in the concentrated solution delivery pipeline and the dilute solution delivery pipeline to exchange heat between the concentrated solution and the dilute solution.

8. The black water waste heat recovery system as described in claim 7, characterized in that, The absorber is equipped with a concentrated solution spraying structure at its hot side input end, and a solution control valve is provided between the absorber and the solution heat exchanger in the concentrated solution delivery pipeline.

9. The black water waste heat recovery system as described in claim 7, characterized in that, The cold side input end of the evaporator is equipped with a refrigerant water spray structure, and the refrigerant water delivery pipeline is equipped with a refrigerant water control valve.

10. The black water waste heat recovery system as described in claim 7, characterized in that, The generator is equipped with a dilute solution spraying structure at the cold side input end, and a solution pump is provided between the absorber and the solution heat exchanger in the dilute solution delivery pipeline.

11. A method for recovering waste heat from black water, characterized in that, The blackwater waste heat recovery system according to any one of claims 1-10, the blackwater waste heat recovery method includes the following steps: Black water side start-up: High-temperature black water is transported to the black water flash evaporation device for flash evaporation. First, the generated high-temperature steam is transported to the hot side of the generator. Then, after the low-temperature steam generated by the black water flash evaporation device reaches its preset temperature, the low-temperature steam is transported to the hot side of the evaporator. Finally, the flash-evaporated low-temperature black water is transported to the hot side of the preheating device for the water to be heated. Heat pump start-up: A dilute solution is delivered to the cold side of the generator; when the temperature of the dilute solution in the generator rises to its preset temperature, refrigerant water vapor in the generator is delivered to the hot side of the condenser; when refrigerant water at the preset temperature is generated on the hot side of the condenser, the refrigerant water is delivered to the cold side of the evaporator; until the refrigerant water exchanges heat with low-temperature steam to form refrigerant water vapor at the preset temperature, the refrigerant water vapor is delivered to the hot side of the absorber; the concentrated solution generated on the cold side of the generator is delivered to the hot side of the absorber. Start-up of the water to be heated: The water to be heated is input into the cold side of the water preheating device to exchange heat with the low-temperature black water; until the water to be heated in the water preheating device reaches the preset temperature, the preheated water is sent to the cold side of the condenser to exchange heat with the refrigerant steam; until the water to be heated in the condenser reaches the preset temperature, the water to be heated is sent to the cold side of the absorber; until the water to be heated in the absorber reaches the preset temperature; The black water waste heat recovery system has entered a stable operation phase.

12. The black water waste heat recovery method as described in claim 11, characterized in that, The blackwater waste heat recovery method further includes adjusting the blackwater waste heat recovery system during the stable operation phase: Monitor the output parameters of the external heat source supplied by the black water waste heat recovery system; Based on the output parameters of the external heat source, the real-time load of the external heat source is analyzed and determined; The black water waste heat recovery system is adjusted according to the real-time load and load demand of the external heat source under different load conditions.

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