A high-temperature waste heat cascade recovery compression heat pump system and a method for operating the same

Abstract

The application discloses a high-temperature waste heat cascade recovery compression type heat pump system and an operation method thereof, comprising a high-temperature stage compression type heat pump circuit, a medium-temperature stage compression type heat pump circuit, a flash tank, a water tank and a water vapor compressor. High-temperature waste heat water is flashed to generate steam and condensed water, part of the condensed water is returned to the flash tank after being heat-absorbed by a high-temperature stage condenser, and the rest of the condensed water enters the water tank; the heat source water output by a high-temperature stage evaporator is branched to a medium-temperature stage condenser and a medium-temperature stage evaporator, the medium-temperature stage compression type heat pump circuit transfers the heat released by one branch of heat source water to another branch of heat source water, the heated heat source water is returned to the water tank, mixed with the condensed water in the water tank and then supplied to the high-temperature stage evaporator again, and the cooled heat source water is discharged from the system; the steam generated by the flash tank is sent to the steam compressor to generate steam with higher pressure. The application can improve the heat matching between different temperature stages of the compression type heat pump, reduce the heat exchange temperature difference of the high-temperature stage evaporation side and realize the cascade deep recovery of the high-temperature waste heat.

Description

Technical Field

[0001] This invention belongs to the technical field of compression heat pumps and industrial waste heat recovery, specifically relating to a high-temperature waste heat cascade recovery compression heat pump system and its operation method. Background Technology

[0002] Large amounts of high-temperature waste heat are typically generated in thermal power plants, oil and gas processing, and other industrial production processes. Currently, the high-temperature steam required in these processes is still largely produced using fuel-fired boilers, which not only consumes a significant amount of non-renewable energy but also generates corresponding pollutant emissions. Therefore, employing heat pump technology to recover industrial waste heat, improve its temperature grade, and further meet industrial heating or steam production needs has become an important technological direction in the field of industrial energy conservation.

[0003] Compression heat pumps typically consist of a compressor, condenser, throttling device, and evaporator forming a refrigerant cycle. The evaporator absorbs heat from the heat source medium, and the condenser releases heat to the heat transfer medium, thus transferring heat from a lower temperature side to a higher temperature side. Existing technologies already exist that utilize compression heat pumps to recover industrial waste heat and further combine them with flash evaporation or steam compression technology to produce high-temperature, high-pressure steam.

[0004] However, due to limitations imposed by the properties of the refrigerant, compressor operating conditions, and the temperature range of the heat pump cycle, high-temperature waste water exceeding 100°C generated in scenarios such as thermal power plants, if directly used as a heat source for the evaporator of a compression heat pump, can easily lead to a significant temperature difference between the high-temperature waste water and the heat pump evaporation temperature. This increases energy efficiency losses during heat exchange and reduces the overall operating efficiency of the heat pump system. Existing heat pumps are prone to significant energy efficiency losses when absorbing high-temperature waste heat above 100°C due to the large temperature difference between the heat source and the evaporation temperature.

[0005] Furthermore, when using a single-stage heat pump to recover high-temperature waste heat, the heat source medium after heat absorption by the heat pump evaporator may still have a relatively high temperature. The remaining heat cannot be fully utilized, and the discharged waste water may require further cooling. Simply adding another heat pump unit can be problematic, as different temperature-rated heat pump units have corresponding applicable operating temperature ranges. Lower-temperature-rated heat pump units can operate at lower heat source temperatures, continuing to absorb the low-grade heat remaining after the preceding heat exchange. However, due to limitations imposed by the properties of the circulating working fluid, the compressor's operating range, and the allowable pressure ratio, the temperature of the heat transfer medium achievable on its condenser side is limited, making it difficult to directly raise the lower-temperature heat source to the temperature required for high-temperature heating or steam generation. If the higher temperature requirement is directly met by increasing the temperature rise of the single-stage heat pump, it can easily lead to an increase in the compression ratio and energy consumption, thus affecting the heat pump's operating efficiency.

[0006] Therefore, it is necessary to provide a high-temperature waste heat cascade recovery compression heat pump system and its operation method. By coupling the heat source medium and heat transfer medium between the high-temperature stage compression heat pump circuit and the medium-temperature stage compression heat pump circuit, the medium-temperature stage compression heat pump circuit can transfer part of the heat released by the heat source medium to another part of the heat source medium, and return the heat source medium after heat absorption to the heat source side of the high-temperature stage compression heat pump circuit. This improves the heat matching between heat pumps of different temperature stages, reduces the heat exchange temperature difference of the high-temperature stage evaporator, and realizes the cascade deep recovery of high-temperature waste heat. Summary of the Invention

[0007] To address the aforementioned technical problems in the existing technology, this invention proposes a high-temperature waste heat cascade recovery compression heat pump system and its operation method to solve the above-mentioned technical problems.

[0008] According to a first aspect of the present invention, a high-temperature waste heat cascade recovery compression heat pump system is provided, comprising a high-temperature stage compression heat pump circuit, a medium-temperature stage compression heat pump circuit, a flash tank, a water tank, and a steam compressor. The high-temperature stage compression heat pump circuit includes a high-temperature stage compressor, a high-temperature stage condenser, a first throttling component, and a high-temperature stage evaporator connected in sequence to form a first refrigerant circulation circuit. The medium-temperature stage compression heat pump circuit includes a medium-temperature stage compressor, a medium-temperature stage condenser, a second throttling component, and a medium-temperature stage evaporator connected in sequence to form a second refrigerant circulation circuit. The flash tank is connected to a high-temperature waste heat input pipeline to receive high-temperature waste hot water and generate low-pressure steam and condensate. The condensate output side of the flash tank is divided into a first condensate branch and a second condensate branch. The first condensate branch is connected to the heat transfer medium input side of the high-temperature stage condenser, and the heat transfer medium output side of the high-temperature stage condenser is connected to the flash tank so that the condensate heated by the high-temperature stage condenser returns to the flash tank. The second condensate branch is connected to the first input side of the water tank. The second input side of the water tank is connected to the heat transfer medium output side of the intermediate temperature stage condenser, and the output side of the water tank is connected to the heat source medium input side of the high temperature stage evaporator. The heat source medium output side of the high-temperature stage evaporator is divided into a first heat source branch and a second heat source branch. The first heat source branch is connected to the heat transfer medium input side of the medium-temperature stage condenser so that the water heated by the medium-temperature stage condenser returns to the water tank. The second heat source branch is connected to the heat source medium input side of the medium-temperature stage evaporator. The heat source medium output side of the medium-temperature stage evaporator is connected to the waste heat discharge pipeline. The flash tank's low-pressure steam output side is connected to the input side of the steam compressor; the flash tank is also connected to the steam compressor's cooling water input side via a cooling water pipeline, allowing some of the condensate in the flash tank to be transported to the steam compressor as cooling water. By setting up a high-temperature stage compression heat pump circuit and a medium-temperature stage compression heat pump circuit, and coupling the two compression heat pump circuits together through a special heat source medium and heat transfer medium water circuit, the medium-temperature stage compression heat pump circuit can absorb heat from a portion of the heat source water output from the high-temperature stage evaporator, transfer this heat to another portion of the heat source water, and then return the heat-absorbing heat source water to the high-temperature stage evaporator's supply water cycle. This enables internal heat transfer and reflux between compression heat pumps of different temperature stages, improves the matching degree between waste heat at different temperature grades, reduces the heat exchange temperature difference of the high-temperature stage evaporator, and further improves the utilization rate of high-temperature waste heat.

[0009] In a specific embodiment, the flash tank is equipped with a high-temperature waste heat inlet and a high-temperature stage heat collection water inlet. The high-temperature waste heat inlet is connected to a high-temperature waste heat input pipeline, and the high-temperature stage heat collection water inlet is connected to the heat transfer medium output side of the high-temperature stage condenser, so that the high-temperature waste water and the condensate heated by the high-temperature stage condenser enter the flash tank for flash evaporation respectively. By allowing the original high-temperature waste water and the condensate heated by the high-temperature stage condenser to enter the flash tank separately, the direct utilization of high-temperature waste heat can be combined with the condensation heat release process of the high-temperature stage compression heat pump circuit, so that the heat released by the high-temperature stage condenser can be further used for flash evaporation to produce steam, thereby improving the utilization rate of heat on the condenser side of the heat pump.

[0010] In a specific embodiment, the water tank is used to receive condensate from the second condensate branch and heated water output from the medium-temperature condenser of the medium-temperature compression heat pump loop, and mixes the two to form high-temperature heat source water supplied to the high-temperature evaporator. By mixing the flash condensate with the heat source water heated on the condenser side of the medium-temperature compression heat pump loop in the water tank, the inlet temperature of the high-temperature evaporator can be adjusted while increasing the heat source water flow rate, thus providing the high-temperature evaporator with more suitable heat source conditions and improving the operating status of the high-temperature compression heat pump loop.

[0011] In a specific embodiment, the outlet temperature of the heat transfer medium in the intermediate-temperature stage condenser is lower than the temperature of the condensate transported by the second condensate branch. The outlet water of the intermediate-temperature stage condenser and the condensate transported by the second condensate branch mix in the water tank to form the high-temperature stage heat source water. By making the outlet temperature of the heat transfer medium in the intermediate-temperature stage condenser lower than the temperature of the condensate transported by the second condensate branch, the output water from the intermediate-temperature stage condenser can be used to mix and regulate the temperature of the higher-temperature flash condensate, thereby reducing the inlet heat source temperature of the high-temperature stage evaporator. This maintains a more reasonable matching relationship between the evaporation temperature and the heat source temperature of the high-temperature stage compression heat pump circuit, thereby reducing the heat exchange terminal temperature difference and the corresponding energy efficiency loss.

[0012] In a specific embodiment, the first heat source branch and the second heat source branch are formed by the divergence of the same stream of heat source water output from the high-temperature stage evaporator. The heat source water transported via the first heat source branch absorbs heat transferred from the medium-temperature stage compression heat pump circuit in the medium-temperature stage condenser and then returns to the water tank. The heat source water transported via the second heat source branch further releases heat and cools down in the medium-temperature stage evaporator before being discharged through the waste heat discharge pipeline. By diverting the same stream of heat source water output from the high-temperature stage evaporator into the medium-temperature stage condenser and the medium-temperature stage evaporator respectively, a portion of the heat source water continues to release heat and cool down in the medium-temperature stage evaporator, while the other portion receives heat transferred from the aforementioned heat release branch in the medium-temperature stage compression heat pump circuit in the medium-temperature stage condenser and is heated and flows back. This forms heat transfer between the media on both sides of the medium-temperature stage compression heat pump circuit and heat return between the upper and lower temperature stage heat pumps, improving the deep recovery capability of waste heat.

[0013] In a specific embodiment, under steady-state operation, the high-temperature waste water entering the flash tank also serves as makeup water for the system. The input flow rate of the high-temperature waste water is equal to the sum of the system output steam flow rate and the waste water flow rate discharged through the waste heat discharge pipeline. Utilizing the high-temperature waste water as makeup water for the flash system reduces the need for independent makeup water and establishes a corresponding material balance relationship between waste water input, steam output, and low-temperature waste water discharge, which helps simplify the water supply process and maintain continuous system operation.

[0014] According to a second aspect of the present invention, an operation method for a high-temperature waste heat cascade recovery compression heat pump system as described above is provided, comprising: S1: High-temperature waste water is fed into a flash tank, causing the high-temperature waste water to flash evaporate to form low-pressure steam and condensate, and the condensate is divided into a first part of condensate and a second part of condensate; S2: The high-temperature stage compression heat pump circuit is operated so that the first part of the condensate flows through the heat transfer medium side of the high-temperature stage condenser, absorbs heat and rises in temperature, and then returns to the flash tank to continue flashing, and the second part of the condensate is delivered to the water tank. S3: The heat source water output from the water tank is transported to the heat source medium side of the high-temperature evaporator for heat release, and the heat source water output from the high-temperature evaporator is divided into a first part of heat source water and a second part of heat source water. S4: Run the medium-temperature stage compression heat pump circuit, so that the second part of the heat source water flows through the medium-temperature stage evaporator and releases heat, and the first part of the heat source water flows through the medium-temperature stage condenser and absorbs the heat transferred by the medium-temperature stage compression heat pump circuit. S5: The first part of the heat source water heated by the medium-temperature condenser is transported to the water tank and mixed with the second part of condensate before being resupplyed to the high-temperature evaporator. The second part of the heat source water cooled by the medium-temperature evaporator is discharged from the system. S6: The low-pressure steam output from the flash tank is transported to the steam compressor for compression to obtain finished steam with a pressure higher than that of the low-pressure steam. During the steam compression process, a portion of the condensate in the flash tank is used as cooling water and transported to the steam compressor to cool the steam compression process. By operating the high-temperature stage compression heat pump circuit and the medium-temperature stage compression heat pump circuit respectively, the high-temperature stage compression heat pump circuit first uses the heat required for some of the flash condensate to be increased and returned to the flash stage. Then, the medium-temperature stage compression heat pump circuit transfers a portion of the heat released by the heat source water at the outlet of the high-temperature stage evaporator to another portion of the heat source water, and the water that has absorbed heat returns to the high-temperature stage evaporator side for circulation. A step-by-step heat transfer relationship can be established according to the heat source temperature grade, reducing unreasonable temperature differences in each heat exchange stage and improving the overall waste heat recovery efficiency of the compression heat pump system.

[0015] In a specific embodiment, the temperature of the high-temperature waste water is higher than 105°C, and the outlet water temperature of the heat transfer medium of the medium-temperature stage condenser in the medium-temperature stage compression heat pump loop is lower than the temperature of the second part of condensate. By limiting the temperature relationship between the second part of condensate and the outlet temperature of the heat transfer medium of the medium-temperature stage condenser, it is possible to ensure that the original high-temperature waste heat has the corresponding high-temperature heat utilization conditions, while enabling the heated water output from the medium-temperature stage condenser to form a reasonable mixing temperature with the second part of condensate, thus providing suitable heat source conditions for the high-temperature stage evaporator.

[0016] In a specific embodiment, the temperature of the mixed heat source water output from the water tank is lower than the temperature of the second part of condensate, and the output temperature of the heat source medium of the intermediate-temperature evaporator is lower than the output temperature of the heat source medium of the high-temperature evaporator. Through the above-mentioned temperature gradient relationship, the heated water output from the intermediate-temperature condenser can be mixed with the second part of condensate to reduce the inlet heat source temperature of the high-temperature evaporator. At the same time, the intermediate-temperature evaporator can be used to further recover the residual heat in the heat source water output from the high-temperature evaporator, thereby reducing the heat exchange difference at the high-temperature evaporator and realizing the graded cooling utilization of waste heat.

[0017] In a specific embodiment, the high-temperature waste water also serves as makeup water for the flash tank. Based on the input of the high-temperature waste water and the system's steam output requirements, the flow ratios of the first and second portions of condensate, as well as the flow ratios of the first and second portions of heat source water, are adjusted to ensure that, during steady-state operation, the input flow rate of the high-temperature waste water equals the sum of the system's output steam flow rate and the waste water discharge flow rate. By adjusting the aforementioned two flow ratios according to the input of the high-temperature waste water and the system's steam output requirements, the amount of water participating in the circulating flash evaporation, heat recovery, and final discharge from the system can be adjusted, thereby regulating the discharge flow rate of the waste water to maintain the overall water balance of the system and the stability of the liquid level in the flash tank, improving the stability of continuous system operation.

[0018] Compared with existing technologies, this invention sets up a high-temperature stage compression heat pump circuit and a medium-temperature stage compression heat pump circuit, and specially couples the heat source side and heat carrier side of the two heat pump circuits, enabling the high-temperature waste heat to be utilized in stages according to different temperature grades. The high-temperature waste water first enters the flash tank to directly generate some steam at its higher temperature grade. The condensate after flash evaporation then participates in the high-temperature stage compression heat pump cycle, avoiding the excessive heat exchange temperature difference between the heat source temperature and the evaporation temperature caused by directly absorbing all the high-temperature waste heat with the heat pump.

[0019] Furthermore, the heat source water output from the high-temperature evaporator is divided into two parts. One part enters the medium-temperature evaporator to further release heat, while the other part enters the medium-temperature condenser. The medium-temperature compression heat pump loop enhances and transfers the heat released by the first part of the heat source water to the second part. The heated heat source water then returns to the water tank, mixes with the flash condensate, and is resupplyed to the high-temperature evaporator. This allows the medium-temperature heat pump not only to further recover residual heat but also to return the recovered heat to the heat source cycle of the high-temperature heat pump, forming an internal heat transfer and recycling relationship between the two different temperature-stage compression heat pump loops.

[0020] Through the aforementioned cascade coupling, the inlet heat source temperature of the high-temperature stage evaporator can be reduced while increasing the heat source water flow rate, making the heat source temperature more compatible with the evaporation temperature of the high-temperature stage compression heat pump. This reduces the heat exchange differential and corresponding energy efficiency losses of the high-temperature stage evaporator. Simultaneously, the medium-temperature stage evaporator can continue to absorb the residual heat after evaporation in the high-temperature stage, further reducing the temperature of the heat source water discharged from the system. After multi-stage utilization through flash evaporation, the high-temperature stage heat pump, and the medium-temperature stage heat pump, the high-temperature waste heat can be further reduced from above 105℃ to a lower discharge temperature. Attached Figure Description

[0021] The accompanying drawings are included to provide a further understanding of the embodiments and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments and, together with the description, serve to explain the principles of the invention. Other embodiments and many anticipated advantages of the embodiments will be readily recognized as they become better understood through reference to the following detailed description. Elements in the drawings are not necessarily to scale. The same reference numerals refer to corresponding similar parts.

[0022] Figure 1 A schematic diagram of the system framework of a high-temperature waste heat cascade recovery compression heat pump system according to an embodiment of the present invention is shown; Figure 2 A schematic diagram of the operation method of a high-temperature waste heat cascade recovery compression heat pump system according to an embodiment of the present invention is shown.

[0023] The meanings of the numbers in the diagram are as follows: 1. Flash tank; 2. High-temperature heat pump unit; 3. Water tank; 4. Medium-temperature heat pump unit; 5. Steam compressor; 6. High-temperature condenser; 7. High-temperature evaporator; 8. Medium-temperature condenser; 9. Medium-temperature evaporator; 10. High-temperature waste water pipe; 11. Condensate outlet pipe; 12. Condensate outlet pipe branch one; 13. Condensate outlet pipe branch two; 14. Water tank supply pipe; 15. High-temperature stage... 16. Evaporator outlet water pipe; 17. High-temperature evaporator outlet water pipe branch 1; 18. Medium-temperature condenser outlet water pipe; 19. High-temperature evaporator outlet water pipe branch 2; 20. Waste heat discharge pipe; 21. High-temperature condenser outlet water pipe; 22. Cooling water pipe; 23. Low-pressure steam pipe; 24. High-pressure steam discharge pipe; 25. No. 1 water pump; 26. No. 3 water pump; 27. No. 1 gate valve; 28. No. 2 gate valve. Detailed Implementation

[0024] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0025] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0026] The specific embodiments of the present invention have been described above, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

[0027] Figure 1 A schematic diagram of the system framework of a high-temperature waste heat cascade recovery compression heat pump system according to an embodiment of the present invention is shown, as follows: Figure 1 As shown, the high-temperature waste heat cascade recovery compression heat pump system of this embodiment includes a flash tank 1, a high-temperature stage heat pump unit 2, a water tank 3, a medium-temperature stage heat pump unit 4, and a steam compressor 5. The high-temperature stage heat pump unit 2 includes a high-temperature stage condenser 6 and a high-temperature stage evaporator 7, and the medium-temperature stage heat pump unit 4 includes a medium-temperature stage condenser 8 and a medium-temperature stage evaporator 9.

[0028] In a specific embodiment, the high-temperature heat pump unit 2 constitutes a high-temperature compression heat pump circuit, and the medium-temperature heat pump unit 4 constitutes a medium-temperature compression heat pump circuit. Specifically, the high-temperature compression heat pump circuit further includes a high-temperature compressor and a first throttling component, and the high-temperature compressor, high-temperature condenser 6, first throttling component, and high-temperature evaporator 7 are sequentially connected to form a first refrigerant circulation circuit; the medium-temperature compression heat pump circuit further includes a medium-temperature compressor and a second throttling component, and the medium-temperature compressor, medium-temperature condenser 8, second throttling component, and medium-temperature evaporator 9 are sequentially connected to form a second refrigerant circulation circuit. Figure 1 To simplify the system framework, only the condenser and evaporator in the two-stage heat pump unit that exchange heat with the external heat source medium and heat transfer medium are shown; the compressor and throttling components are not specifically shown. Preferably, the first refrigerant circulation loop of the high-temperature stage compression heat pump circuit (high-temperature stage heat pump unit 2) uses R1233zd(E) as the working fluid; the second refrigerant circulation loop of the medium-temperature stage compression heat pump circuit (medium-temperature stage heat pump unit 4) uses R134a as the working fluid.

[0029] In the operation of the high-temperature stage compression heat pump circuit, the refrigerant absorbs heat from the external heat source medium in the high-temperature stage evaporator 7, is compressed by the high-temperature stage compressor, enters the high-temperature stage condenser 6, and releases heat to the heat transfer medium in the high-temperature stage condenser 6. Then, after being depressurized by the first throttling device, it re-enters the high-temperature stage evaporator 7, thus forming the first refrigerant cycle. Similarly, in the medium-temperature stage compression heat pump circuit, the refrigerant absorbs heat in the medium-temperature stage evaporator 9, is compressed by the medium-temperature stage compressor, enters the medium-temperature stage condenser 8, releases heat to the corresponding heat transfer medium in the medium-temperature stage condenser 8, and then returns to the medium-temperature stage evaporator 9 through the second throttling device, thus forming the second refrigerant cycle.

[0030] Flash tank 1 is connected to a high-temperature waste water pipeline 10. High-temperature waste water from a thermal power plant or other industrial processes is directly input into flash tank 1 via the high-temperature waste water pipeline 10. After entering flash tank 1, the high-temperature waste water undergoes depressurization and flash evaporation within flash tank 1, thereby directly utilizing its high temperature grade to generate low-pressure steam and condensate. Compared to using all the high-temperature waste water directly as the evaporation heat source for a compression heat pump, this method can first utilize the high temperature grade of the high-temperature waste heat itself to directly generate some steam, thereby reducing the large heat exchange temperature difference caused by the high-temperature heat source directly entering the evaporation side of the heat pump. In this embodiment, 124°C high-temperature waste water directly enters the flash tank and forms 105°C saturated steam and condensate as a typical example.

[0031] In a specific embodiment, the condensate outlet of the flash tank 1 is connected to a condensate outlet pipe 11, which is further divided into a first condensate outlet pipe branch 12 and a second condensate outlet pipe branch 13. The first condensate outlet pipe branch 12 is connected to the heat transfer medium input side of the high-temperature stage condenser 6, and the heat transfer medium output side of the high-temperature stage condenser 6 is connected to the flash tank 1 via a high-temperature stage condenser outlet pipe 20. Thus, a portion of the condensate output from the flash tank 1 enters the high-temperature stage condenser 6 via the first condensate outlet pipe branch 12, where it absorbs heat released by the first refrigerant cycle and heats up. It then returns to the flash tank 1 via the high-temperature stage condenser outlet pipe 20 for flash evaporation again. Therefore, the condenser side of the high-temperature compression heat pump circuit does not supply heat to the external heat-using end alone, but instead gives the increased heat to a portion of the condensate output from the flash tank 1, and then allows this portion of condensate to return to the flash tank 1 to continue generating steam, so that the condensation heat released by the high-temperature compression heat pump circuit can re-enter the flash steam generation process.

[0032] On the other hand, condensate outlet pipe branch 13 is connected to the first input side of water tank 3, allowing another portion of the condensate output from flash tank 1 to enter water tank 3. Water tank 3 also has a second input side, which is connected to the heat transfer medium output side of intermediate temperature stage condenser 8 via intermediate temperature stage condenser outlet pipe 17; the output side of water tank 3 is connected to the heat source medium input side of high temperature stage evaporator 7 via water tank supply pipe 14. Thus, the condensate from flash tank 1 and the heated water output from intermediate temperature stage condenser 8 are mixed in water tank 3, and the mixed water is transported to the high temperature stage evaporator 7 as the heat source medium of the high temperature stage compression heat pump circuit.

[0033] By mixing the water output from the intermediate-temperature condenser 8 with the flash condensate in the water tank 3, the flow rate of the heat source medium supplied to the high-temperature evaporator 7 can be increased. Simultaneously, the temperature of the heat source medium entering the high-temperature evaporator 7 can be adjusted, making the temperature of the heat source medium more closely match the evaporation temperature of the high-temperature compression heat pump circuit. This mixing method increases the flow rate of the high-temperature heat source water while reducing the temperature of the heat source water entering the high-temperature evaporator, thereby reducing the heat exchange differential and increasing the heat exchange capacity of the high-temperature heat pump.

[0034] In a specific embodiment, the heat source medium output side of the high-temperature evaporator 7 is connected to the high-temperature evaporator outlet water pipe 15, which is further divided into a first branch 16 and a second branch 18. The first branch 16 connects to the heat transfer medium input side of the medium-temperature condenser 8, while the second branch 18 connects to the heat source medium input side of the medium-temperature evaporator 9. Therefore, the same stream of heat source water output from the high-temperature evaporator 7 is divided into two parts: the first part enters the medium-temperature condenser 8 via the first branch 16, serving as the heat transfer medium on the condensing side of the medium-temperature compression heat pump loop; the second part enters the medium-temperature evaporator 9 via the second branch 18, serving as the heat source medium on the evaporating side of the medium-temperature compression heat pump loop.

[0035] During the operation of the intermediate-temperature stage compression heat pump loop, the second portion of heat source water entering the intermediate-temperature stage evaporator 9 continues to release its residual heat, further reducing its temperature, and is discharged from the system through the waste heat discharge pipe 19. Simultaneously, the heat absorbed by the intermediate-temperature stage evaporator 9 is transferred through the second refrigerant cycle and released in the intermediate-temperature stage condenser 8, causing the first portion of heat source water entering the intermediate-temperature stage condenser 8 to absorb heat and increase its temperature. The heated first portion of heat source water returns to the water tank 3 through the intermediate-temperature stage condenser outlet pipe 17, mixes with the condensate entering the water tank 3 through the condensate outlet pipe branch 13, and then serves again as the heat source medium for the high-temperature stage evaporator 7. Thus, the intermediate-temperature stage compression heat pump loop actually transfers heat between the two portions of the same heat source water output from the high-temperature stage evaporator 7: one portion of the heat source water continues to release heat and decrease in temperature, while the other portion receives the transferred heat, increases in temperature, and returns to the high-temperature stage compression heat pump loop. In this way, an internal heat return relationship can be formed between "high-temperature evaporator 7 - medium-temperature evaporator 9 / medium-temperature condenser 8 - water tank 3 - high-temperature evaporator 7", so that the residual heat recovered by the medium-temperature compression heat pump circuit can re-participate in the next stage heat pump cycle, instead of simply being output to the external heat-using end.

[0036] In a specific embodiment, the low-pressure steam generated by the flash tank 1 is transported to the steam compressor 5 via the low-pressure steam pipeline 22. The steam compressor 5 compresses the low-pressure steam, increasing its pressure and temperature, and outputs it through the high-pressure steam discharge pipeline 23 to meet industrial steam demand. The flash tank 1 is also connected to the cooling water input side of the steam compressor 5 via a cooling water pipeline, so that some of the condensate in the flash tank 1 is transported to the steam compressor 5 as cooling water. In this embodiment, the steam compressor 5 mainly serves as the steam output pressure boosting unit of the high-temperature waste heat cascade recovery compression heat pump system, without changing the thermal coupling relationship between the two compression heat pump circuits mentioned above.

[0037] In one specific embodiment, the temperature of the high-temperature waste water can be 124°C. The high-temperature waste water first enters the flash tank 1 and flashes to form saturated steam and condensate at approximately 105°C. Part of the condensate is heated to approximately 110°C by the high-temperature stage condenser 6 and then returned to the flash tank 1. Another part of the condensate enters the water tank 3 and mixes with the approximately 85°C heat source water output from the medium-temperature stage condenser 8 to form high-temperature stage heat source water at approximately 88°C. This heat source water enters the high-temperature stage evaporator 7 and is cooled to approximately 75°C. It is then diverted to the medium-temperature stage condenser 8 and the medium-temperature stage evaporator 9. The portion of the heat source water entering the medium-temperature stage evaporator 9 is further cooled to approximately 32°C before being discharged.

[0038] Through the coupling relationship between the aforementioned two-stage compression heat pump loop and its external heat source medium and heat transfer medium, high-temperature waste heat can be sequentially processed through direct flash evaporation, high-temperature stage compression heat pump recovery, and further recovery by the medium-temperature stage compression heat pump. A portion of the heat recovered by the medium-temperature stage compression heat pump is then returned to the heat source cycle of the high-temperature stage heat pump, thereby improving the heat matching between different temperature grades. After multi-stage utilization, the high-temperature waste heat can be reduced to below 35℃, while simultaneously reducing the heat exchange differential at the high-temperature stage evaporator and increasing the heat exchange capacity of the heat pump.

[0039] In a specific embodiment, a first water pump 24 can be installed on the condensate outlet pipe 11, and a second water pump 25 can be installed on the water tank supply pipe 14 to provide circulating power for the corresponding water circuits. A first gate valve 27 and a second gate valve 28 can also be installed on the corresponding branch lines to regulate the flow rate of the corresponding branch. The flash tank 1 can also supply cooling water to the steam compressor 5 through the cooling water pipe 21, and a third water pump 26 can be installed on the cooling water pipe 21. The above-mentioned pumps and valves can be configured and adjusted according to the actual operating conditions of the system.

[0040] Continue to refer to Figure 2 , Figure 2 A schematic diagram of the operation method of a high-temperature waste heat cascade recovery compression heat pump system according to an embodiment of the present invention is shown, such as... Figure 2 As shown, the running method includes the following steps: S1: High-temperature waste water is fed into a flash tank, where it flashes to form low-pressure steam and condensate, and the condensate is divided into a first part of condensate and a second part of condensate.

[0041] In a specific embodiment, the high-temperature waste water is directly fed into the flash tank, where it undergoes depressurization flash evaporation to form low-pressure saturated steam and condensate. This prioritizes utilizing the relatively high temperature and grade of the waste water to generate some steam, eliminating the need to use all of the waste water as a heat source for the heat pump evaporator. The temperature of the waste water can exceed 105°C. For example, under typical operating conditions, the waste water temperature is 124°C, which, after flash evaporation, forms saturated steam at approximately 105°C and condensate at approximately 105°C. Further, the condensate formed during flash evaporation is divided into a first portion and a second portion after output. The first portion is reheated by the high-temperature stage compression heat pump loop and returned to the flash tank, while the second portion enters the water tank to participate in the mixing and regulation of the heat source water in the high-temperature stage evaporator. Through this diversion, the condensate after flash evaporation can perform both circulating flash evaporation and heat source temperature regulation functions.

[0042] S2: The high-temperature stage compression heat pump circuit is operated so that the first part of the condensate flows through the heat transfer medium side of the high-temperature stage condenser, absorbs heat and rises in temperature, and then returns to the flash tank to continue flashing, while the second part of the condensate is delivered to the water tank.

[0043] In a specific embodiment, during the operation of the high-temperature stage compression heat pump loop, the high-temperature stage evaporator absorbs heat from its heat source medium, and the high-temperature stage compressor compresses the refrigerant, causing the refrigerant to release heat to the first portion of condensate in the high-temperature stage condenser, thereby raising the temperature of the first portion of condensate. The heated first portion of condensate is then returned to the flash tank for further flash evaporation, so that the heat gained by the high-temperature stage compression heat pump loop can be reused for steam generation. For example, under the typical operating conditions described above, a portion of the approximately 105°C condensate formed by flash evaporation can be heated to approximately 110°C by the high-temperature stage condenser and returned to the flash tank, thereby generating low-pressure saturated steam at approximately 105°C again. The saturated steam in the flash tank can therefore include steam formed by direct flash evaporation of the original high-temperature waste water and steam formed by flash evaporation of condensate reheated by the high-temperature stage condenser. Another portion of the condensate is sent to a water tank to be mixed with heated water output from the intermediate-temperature stage condenser in subsequent steps. In actual operation, the flow ratio between the first part of condensate and the second part of condensate can be adjusted according to the flash steam production, the high-temperature heat pump load, and the required amount of mixed water in the water tank.

[0044] S3: The heat source water output from the water tank is transported to the heat source medium side of the high-temperature evaporator for heat release, and the heat source water output from the high-temperature evaporator is divided into a first part of heat source water and a second part of heat source water.

[0045] In a specific embodiment, the heat source water in the tank is formed by mixing the second portion of condensate with the first portion of heat source water subsequently returned from the intermediate-temperature stage condenser. This mixing increases the flow rate of heat source water supplied to the high-temperature stage evaporator while simultaneously regulating the temperature of the heat source entering the high-temperature stage evaporator, thereby reducing the temperature difference between the high-temperature heat source water and the evaporation temperature of the high-temperature stage compression heat pump loop. For example, under typical operating conditions, the water temperature output from the intermediate-temperature stage condenser is approximately 85°C. After mixing with the flash condensate entering the tank, it forms heat source water at a temperature of approximately 88°C. This heat source water then releases heat and cools down to approximately 75°C after entering the high-temperature stage evaporator. This mixing method simultaneously increases the heat source flow rate of the high-temperature stage evaporator and reduces the heat source inlet temperature, thereby reducing the heat exchange differential. Furthermore, the heat source water that has released heat after passing through the high-temperature stage evaporator is not directly discharged in its entirety, but is further divided into a first portion of heat source water and a second portion of heat source water, which serve as the heat transfer medium on the condenser side and the heat source medium on the evaporation side of the intermediate-temperature compression heat pump loop, respectively.

[0046] S4: The medium-temperature stage compression heat pump circuit is operated, so that the second part of the heat source water flows through the medium-temperature stage evaporator and releases heat, and the first part of the heat source water flows through the medium-temperature stage condenser and absorbs the heat transferred by the medium-temperature stage compression heat pump circuit.

[0047] In a specific embodiment, during the operation of the medium-temperature stage compression heat pump loop, the second portion of heat source water serves as the heat source medium for the medium-temperature stage evaporator, continuing to release residual heat within it. The heat absorbed by the medium-temperature stage evaporator is then boosted by the medium-temperature stage compressor and released in the medium-temperature stage condenser, where it is absorbed by the first portion of heat source water. Thus, the medium-temperature stage compression heat pump loop achieves heat transfer between the two portions of heat source water from the high-temperature stage evaporator. The second portion of heat source water continues to cool and release residual heat, while the first portion absorbs the transferred heat and heats up. The medium-temperature stage compression heat pump loop thereby transfers the residual heat from the second portion of heat source water to the first portion, rather than directly releasing the recovered heat to the outside of the system. During operation, the flow ratio of the first and second portions of heat source water can be adjusted to regulate the waste heat recovery load of the medium-temperature stage evaporator and the heat carrying capacity of the medium-temperature stage condenser, ensuring that the heat exchange on both sides matches the heat source demand of the high-temperature stage heat pump.

[0048] S5: The first part of the heat source water, heated by the medium-temperature stage condenser, is transported to the water tank and mixed with the second part of the condensate before being resupplyed to the high-temperature stage evaporator. The second part of the heat source water, cooled by the medium-temperature stage evaporator, is discharged from the system.

[0049] In a specific embodiment, the first portion of the heat source water, after absorbing heat and heating up in the intermediate-temperature condenser, returns to the water tank and mixes with the second portion of condensate from the flash tank. This mixed heat source water is then transported back to the high-temperature evaporator, thus forming a heat source water return path of "high-temperature evaporator—intermediate-temperature condenser—water tank—high-temperature evaporator." Simultaneously, the second portion of the heat source water, after further releasing heat in the intermediate-temperature evaporator, is discharged as low-temperature water after the completion of the cascade waste heat recovery process. Through this method, the heat recovered by the intermediate-temperature compression heat pump loop can return to the heat source side of the high-temperature compression heat pump loop, allowing heat from different temperature levels to be recycled within the system, while further cooling the second portion of heat source water to be discharged. Under typical operating conditions, a portion of the approximately 75°C heat source water output from the high-temperature evaporator is further cooled to approximately 32°C by the intermediate-temperature evaporator before being discharged from the system. Furthermore, the outlet water temperature of the heat transfer medium in the medium-temperature stage condenser is lower than the temperature of the condensate in the second section, so that when it is mixed with the condensate in the second section, it can regulate the temperature of the heat source water at the inlet of the high-temperature stage evaporator.

[0050] S6: The low-pressure steam output from the flash tank is delivered to the steam compressor for compression to obtain finished steam with a pressure higher than that of the low-pressure steam. During the steam compression process, part of the condensate in the flash tank is delivered to the steam compressor as cooling water to cool the steam compression process.

[0051] In a specific embodiment, the low-pressure saturated steam generated in the flash tank is input into a steam compressor, which increases its pressure and temperature to obtain finished steam that meets the user's requirements. The input low-pressure steam may simultaneously include steam generated from the initial flash evaporation of high-temperature waste water and steam generated from the first portion of condensate that has been heated by a high-temperature condenser and then returned to the flash tank.

[0052] During the steam compression process, a portion of the condensate can be drawn from the flash tank as cooling water and sent to the steam compressor for intermediate cooling to control the exhaust temperature of the steam compressor. Under typical operating conditions, finished steam with an exhaust superheat of approximately 10°C and a gauge pressure of approximately 6 bar can be obtained. The above pressure and temperature are only given as a specific operating condition and are not intended to limit the scope of protection of this invention.

[0053] In a further embodiment, the temperature of the high-temperature waste water is higher than 105°C, and the outlet water temperature of the heat transfer medium in the intermediate-temperature condenser is lower than the temperature of the second-stage condensate. This temperature relationship ensures that the high-temperature waste water is suitable for direct flash evaporation, and that the heated water output from the intermediate-temperature condenser, when mixed with the flash condensate, can still regulate the inlet heat source temperature of the high-temperature evaporator. It should be noted that the aforementioned 105°C is not the only limiting value for the micro-pressure steam and condensate; it can be adjusted according to the working pressure of the flash tank, the target steam state, and the operating temperature of the two-stage compression heat pump circuit. The use of 124°C high-temperature waste water and 105°C flash saturated steam in this embodiment is merely a specific example.

[0054] In a further embodiment, the flow ratio between the first portion of condensate and the second portion of condensate, as well as the flow ratio between the first portion of heat source water and the second portion of heat source water, can be adjusted. By adjusting the condensate flow ratio, the amount of condensate returning to the high-temperature stage condenser for circulating heating and the amount of condensate entering the water tank for mixing can be changed; by adjusting the heat source water flow ratio, the amount of heat source water entering the medium-temperature stage condenser and the medium-temperature stage evaporator can be changed, thereby adjusting the heat exchange load on both sides of the medium-temperature stage compression heat pump loop. The above-mentioned flow ratio adjustment can also be used to adjust the flow rate of the waste hot water finally discharged from the system through the medium-temperature stage evaporator, so as to maintain the total water balance of the system and the stability of the flash tank liquid level in accordance with the system steam output demand.

[0055] In a further embodiment, the high-temperature waste water also serves as makeup water for the flash tank. Based on the input of the high-temperature waste water and the system's steam output requirements, the flow ratio between the first and second portions of condensate and the flow ratio between the first and second portions of heat source water can be adjusted to regulate the discharge flow of the waste water after cooling in the intermediate-temperature evaporator, thereby maintaining the overall system water balance and a stable liquid level in the flash tank. Under steady-state operation, the input of the high-temperature waste water, the system's steam output, and the discharge of the waste water satisfy the corresponding material balance relationship. Under ideal steady-state material balance, the input flow rate of the high-temperature waste water corresponds to the sum of the system's output steam flow rate and the discharge flow rate of the waste water. This allows the system to replenish the water loss caused by steam output while generating steam using continuously input high-temperature waste water, eliminating the need for a separate flash tank makeup water source.

[0056] In a further embodiment, temperature parameters at corresponding locations of the high-temperature stage compression heat pump circuit, the medium-temperature stage compression heat pump circuit, the flash tank, and the steam compressor can be collected, as well as pressure parameters at corresponding locations of the flash tank and the steam compressor. Based on the collected temperature and pressure parameters, the flow rate of each branch, the operating conditions of the heat pump, and the steam compression process can be adjusted to adapt to different high-temperature waste heat input temperatures, waste heat flow rates, and user steam demands.

[0057] In a specific operational embodiment, high-temperature waste water at approximately 124°C is input into the flash tank, where it forms saturated steam and condensate at approximately 105°C. A portion of the condensate is heated to approximately 110°C by a high-temperature condenser and returned to the flash tank for further flashing; the other portion is sent to the water tank. Water at approximately 85°C output from the intermediate-temperature condenser returns to the water tank and mixes with the condensate to form high-temperature heat source water at approximately 88°C. This high-temperature heat source water releases heat in the high-temperature evaporator, reducing its temperature to approximately 75°C. It then splits into two parts: one part enters the intermediate-temperature condenser, absorbs heat, and returns to the water tank; the other part enters the intermediate-temperature evaporator, further releases heat, and cools to approximately 32°C before being discharged from the system. The approximately 105°C saturated steam output from the flash tank is sent to a steam compressor for compression. Simultaneously, some condensate is drawn from the flash tank for intermediate cooling during the compression process, ultimately yielding finished steam with a gauge pressure of approximately 6 bar and an exhaust superheat of approximately 10°C. Through the above operation process, the high-temperature waste heat is successively recovered through direct flash evaporation, high-temperature stage compression heat pump recovery, and medium-temperature stage compression heat pump. While using the high-temperature waste heat to generate steam, the temperature of the remaining waste heat is gradually reduced, and some of the remaining heat is returned to the heat source cycle of the high-temperature stage heat pump through the medium-temperature stage compression heat pump loop, thereby realizing the cascade and recycling of high-temperature waste heat.

[0058] In the description of this invention, it should be understood that the terms "upper," "lower," "inner," "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The simple fact that certain measures are recited in mutually different dependent claims does not indicate that combinations of these measures cannot be used for improvement. Any reference signs in the claims should not be construed as limiting the scope.

Claims

1. A high-temperature waste heat cascade recovery compression heat pump system, characterized in that, This includes high-temperature stage compression heat pump circuits, medium-temperature stage compression heat pump circuits, flash tanks, water tanks, and steam compressors; The high-temperature stage compression heat pump circuit includes a high-temperature stage compressor, a high-temperature stage condenser, a first throttling component, and a high-temperature stage evaporator connected in sequence to form a first refrigerant circulation circuit. The medium-temperature stage compression heat pump circuit includes a medium-temperature stage compressor, a medium-temperature stage condenser, a second throttling component, and a medium-temperature stage evaporator connected in sequence to form a second refrigerant circulation circuit. The flash tank is connected to a high-temperature waste heat input pipeline for receiving high-temperature waste hot water and generating low-pressure steam and condensate. The condensate output side of the flash tank is divided into a first condensate branch and a second condensate branch. The first condensate branch is connected to the heat transfer medium input side of the high-temperature stage condenser, and the heat transfer medium output side of the high-temperature stage condenser is connected to the flash tank so that the condensate heated by the high-temperature stage condenser returns to the flash tank. The second condensate branch is connected to the first input side of the water tank; The second input side of the water tank is connected to the heat transfer medium output side of the intermediate temperature stage condenser, and the output side of the water tank is connected to the heat source medium input side of the high temperature stage evaporator. The heat source medium output side of the high-temperature stage evaporator is divided into a first heat source branch and a second heat source branch. The first heat source branch is connected to the heat transfer medium input side of the medium-temperature stage condenser so that the water heated by the medium-temperature stage condenser returns to the water tank. The second heat source branch is connected to the heat source medium input side of the medium-temperature stage evaporator. The heat source medium output side of the medium-temperature stage evaporator is connected to the waste heat discharge pipeline. The low-pressure steam output side of the flash tank is connected to the input side of the steam compressor; the flash tank is also connected to the cooling water input side of the steam compressor through a cooling water pipeline, so that part of the condensate in the flash tank is transported to the steam compressor as cooling water.

2. The high-temperature waste heat cascade recovery compression heat pump system according to claim 1, characterized in that, The flash tank is equipped with a high-temperature waste heat inlet and a high-temperature heat collection water inlet. The high-temperature waste heat inlet is connected to the high-temperature waste heat input pipeline, and the high-temperature heat collection water inlet is connected to the heat transfer medium output side of the high-temperature condenser, so that the high-temperature waste water and the condensate heated by the high-temperature condenser enter the flash tank for flash evaporation.

3. The high-temperature waste heat cascade recovery compression heat pump system according to claim 1, characterized in that, The water tank is used to receive the condensate transported by the second condensate branch and the heated water output from the medium-temperature stage condenser of the medium-temperature stage compression heat pump circuit, and mix the two to form high-temperature stage heat source water supplied to the high-temperature stage evaporator.

4. The high-temperature waste heat cascade recovery compression heat pump system according to claim 3, characterized in that, The outlet water temperature of the heat transfer medium of the intermediate-temperature stage condenser is lower than the temperature of the condensate transported by the second condensate branch. The outlet water of the intermediate-temperature stage condenser and the condensate transported by the second condensate branch are mixed in the water tank to form the high-temperature stage heat source water.

5. The high-temperature waste heat cascade recovery compression heat pump system according to claim 1, characterized in that, The first heat source branch and the second heat source branch are formed by the same stream of heat source water output from the high-temperature stage evaporator. The heat source water transported by the first heat source branch absorbs the heat transferred by the medium-temperature stage compression heat pump circuit in the medium-temperature stage condenser and then returns to the water tank. The heat source water transported by the second heat source branch further releases heat and cools down in the medium-temperature stage evaporator and is then discharged through the waste heat discharge pipeline.

6. The high-temperature waste heat cascade recovery compression heat pump system according to claim 1, characterized in that, Under steady-state operation, the high-temperature waste water entering the flash tank also serves as the system's makeup water. The input flow rate of the high-temperature waste water is equal to the sum of the system's output steam flow rate and the waste water flow rate discharged through the waste heat discharge pipeline.

7. A method for operating a high-temperature waste heat cascade recovery compression heat pump system as described in any one of claims 1-6, characterized in that, include: S1: High-temperature waste water is fed into a flash tank, causing the high-temperature waste water to flash evaporate to form low-pressure steam and condensate, and the condensate is divided into a first part of condensate and a second part of condensate; S2: Run the high-temperature stage compression heat pump circuit, so that the first part of condensate flows through the heat transfer medium side of the high-temperature stage condenser and absorbs heat to increase its temperature before returning to the flash tank to continue flash evaporation, and delivers the second part of condensate to the water tank. S3: The heat source water output from the water tank is transported to the heat source medium side of the high-temperature evaporator for heat release, and the heat source water output from the high-temperature evaporator is divided into a first part of heat source water and a second part of heat source water. S4: Run the medium-temperature stage compression heat pump circuit, so that the second part of the heat source water flows through the medium-temperature stage evaporator and releases heat, and so that the first part of the heat source water flows through the medium-temperature stage condenser and absorbs the heat transferred by the medium-temperature stage compression heat pump circuit. S5: The first part of the heat source water heated by the medium-temperature condenser is transported to the water tank and mixed with the second part of condensate before being resupplyed to the high-temperature evaporator. The second part of the heat source water cooled by the medium-temperature evaporator is discharged from the system. S6: The low-pressure steam output from the flash tank is delivered to the steam compressor for compression to obtain finished steam with a pressure higher than that of the low-pressure steam. During the steam compression process, part of the condensate in the flash tank is delivered to the steam compressor as cooling water to cool the steam compression process.

8. The operating method according to claim 7, characterized in that, The temperature of the high-temperature waste water is higher than 105°C, and the outlet water temperature of the heat transfer medium of the medium-temperature stage condenser in the medium-temperature stage compression heat pump circuit is lower than the temperature of the second part of the condensate.

9. The operating method according to claim 7, characterized in that, The temperature of the mixed heat source water output from the water tank is lower than the temperature of the second part of condensate, and the output temperature of the heat source medium of the medium-temperature evaporator is lower than the output temperature of the heat source medium of the high-temperature evaporator.

10. The operating method according to claim 7, characterized in that, The high-temperature waste water also serves as makeup water for the flash tank. Based on the input of the high-temperature waste water and the system's steam output requirements, the flow ratio of the first part of condensate to the second part of condensate, as well as the flow ratio of the first part of heat source water to the second part of heat source water, are adjusted to regulate the discharge flow of waste water, maintain the total water balance of the system, and stabilize the liquid level in the flash tank.

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