Coal chemical black water waste heat refrigerating system

Abstract

The utility model discloses a coal chemical industry black water waste heat refrigerating system which comprises a coal chemical industry black water tower, a first heat exchanger, a lithium bromide refrigerating unit, a first water conveying channel and a second water conveying channel. The black water tower conveys black water to the first heat exchanger through the first water conveying channel so as to heat the heat-conducting medium in the second water conveying channel; the second water conveying channel comprises a high-temperature pipeline and a low-temperature pipeline, a temperature control valve set is arranged at the water outlet end of the first heat exchanger, and the temperature control valve set can control one of the high-temperature pipeline and the low-temperature pipeline to be communicated with the water outlet end. The heat pump condenser can heat the heat-conducting medium in the low-temperature pipeline to the temperature larger than or equal to the preset temperature and then convey the heat-conducting medium to a generator of the lithium bromide refrigeration unit. The problem that the black water temperature fluctuation is large is solved, stable heat output of the lithium bromide refrigeration unit is achieved, and the refrigeration stability of the lithium bromide refrigeration unit can be improved.

Description

Technical Field

[0001] This application belongs to the field of black water waste heat recovery and utilization technology, specifically relating to a coal chemical black water waste heat refrigeration system. Background Technology

[0002] Black water generated during coal chemical production is a type of industrial wastewater characterized by high temperature, high corrosivity, and high solids content. Its temperature typically ranges from 60 to 120°C, and it contains a significant amount of waste heat. Traditional black water treatment primarily relies on direct cooling with cooling towers, which not only wastes heat energy but also requires additional electricity to power the cooling equipment. In recent years, technologies for recovering waste heat from black water for refrigeration have gained increasing attention, particularly lithium bromide absorption refrigeration technology. Because it can utilize medium- and low-temperature heat sources to drive the refrigeration cycle, it is considered an effective way to utilize waste heat from coal chemical production.

[0003] However, due to the large temperature fluctuations of black water in coal chemical production, and the fact that lithium bromide refrigeration systems require a relatively stable high-temperature heat source (typically above 75°C to 85°C), the efficiency of the lithium bromide refrigeration system drops sharply when the black water temperature is low. This leads to frequent start-ups and shutdowns, affecting equipment lifespan. Furthermore, the heat energy contained in the low-temperature black water cannot be effectively utilized, resulting in waste heat. In addition, the inability of black water to provide a stable heat source to the lithium bromide refrigeration system leads to unstable cooling output, failing to meet operational requirements. Utility Model Content

[0004] This application provides a coal chemical black water waste heat refrigeration system to solve the technical problems of unstable cooling by lithium bromide refrigeration units and waste of low-temperature black water waste heat caused by the instability of black water waste heat in traditional technologies.

[0005] The technical solution adopted in this application is as follows:

[0006] A waste heat cooling system for coal chemical black water includes a coal chemical black water tower, a first heat exchanger, a lithium bromide refrigeration unit, a first water supply passage connecting the coal chemical black water tower and the first heat exchanger, and a second water supply passage connecting the first heat exchanger and the lithium bromide refrigeration unit. The second water supply passage is filled with a heat-conducting medium. The coal chemical black water tower supplies black water to the first heat exchanger through the first water supply passage to heat the heat-conducting medium in the second water supply passage. The second water supply passage includes a high-temperature pipeline and a low-temperature pipeline. A temperature control valve assembly is provided at the outlet of the first heat exchanger, and the temperature control valve assembly can control the high-temperature pipeline and the low-temperature pipeline. The low-temperature pipeline is selectively connected to the water outlet. The temperature control valve group is configured such that: when the temperature of the heat transfer medium at the water outlet is ≥ a preset temperature, the high-temperature pipeline is connected to the water outlet; when the temperature of the heat transfer medium at the water outlet is < a preset temperature, the low-temperature pipeline is connected to the water outlet. The refrigeration system also includes a heat pump unit, which includes a heat pump evaporator, a compressor, a heat pump condenser, and an expansion valve. The heat release end of the heat pump condenser is connected to the low-temperature pipeline. The heat pump condenser can heat the heat transfer medium in the low-temperature pipeline to ≥ a preset temperature and then deliver it to the generator of the lithium bromide refrigeration unit.

[0007] The waste heat refrigeration system for black water from coal chemical industry described in this application also includes the following additional technical features:

[0008] The refrigeration system further includes a regenerative pipeline connecting the heat absorption end of the heat pump evaporator to the heat dissipation end of the lithium bromide refrigeration unit, and the lithium bromide refrigeration unit delivers heat to the heat pump evaporator through the regenerative pipeline.

[0009] The refrigeration system further includes a second heat exchanger and a third heat exchanger. The high-temperature pipeline delivers heat to the generator of the lithium bromide refrigeration unit through the second heat exchanger, and the low-temperature pipeline delivers heat to the generator of the lithium bromide refrigeration unit through the third heat exchanger. The high-temperature pipeline passes through the second heat exchanger and is connected to the inlet of the first heat exchanger. The low-temperature pipeline passes through the heat pump unit and the third heat exchanger in sequence and is connected to the inlet of the first heat exchanger.

[0010] The first water conveyance passage passes through the first heat exchanger and is connected to the inlet of the coal chemical black water tower.

[0011] The refrigeration system further includes an outlet pipe that connects the outlet end to the second water supply passage. The temperature control valve group includes a temperature sensor installed on the outer wall of the outlet pipe, a controller, and a three-way solenoid valve. The inlet of the three-way solenoid valve is connected to the outlet pipe, and the two outlets of the three-way solenoid valve are respectively connected to the high-temperature pipeline and the low-temperature pipeline. The controller controls one of the outlets of the three-way solenoid valve to open according to the monitoring signal of the temperature sensor.

[0012] The refrigeration system also includes a filtration unit located between the coal chemical black water tower and the first heat exchanger. The filtration unit is capable of filtering black water impurities in the first water supply path and transmitting the filtered black water to the first heat exchanger through the first water supply path.

[0013] The preset temperature is 80℃.

[0014] The first heat exchanger has a heat inlet passage that is connected to the first water supply passage, and the inner wall of the heat inlet passage is provided with an anti-corrosion layer.

[0015] Along the black water flow path, a first filter screen and a second filter screen are sequentially provided in the heat inlet passage and are detachably connected to the first heat exchanger. The pore size of the first filter screen is larger than that of the second filter screen.

[0016] Preferably, a booster pump is provided in the first water conveyance passage, the high-temperature pipeline, and the low-temperature pipeline to pump the black water or heat transfer medium in the pipeline.

[0017] Due to the adoption of the above technical solution, the beneficial effects achieved by this application are as follows:

[0018] 1. The black water waste heat cooling system of this application is equipped with a first heat exchanger, a first water supply passage, and a second water supply passage, realizing heat exchange between black water and a heat-conducting medium. This avoids the corrosion and blockage problems that may occur if black water directly enters the lithium bromide cooling system. The heat-conducting medium, as an intermediate heat transfer medium, can effectively isolate corrosive components and solid impurities in the black water, protecting key components of the lithium bromide cooling unit and helping to extend its service life. Secondly, the second water supply path includes high-temperature and low-temperature pipelines, equipped with a temperature-controlled valve assembly. When the black water temperature is high enough to provide sufficient heat to the heat transfer medium to reach a preset temperature, the high-temperature pipeline connects to the outlet of the first heat exchanger to transfer the heat transfer medium to the lithium bromide refrigeration unit. Conversely, when the black water temperature is insufficient to provide enough heat to the heat transfer medium, and the temperature of the heat transfer medium is below the preset temperature, the temperature-controlled valve assembly connects the low-temperature pipeline to the outlet of the first heat exchanger, transferring the low-temperature heat transfer medium to the heat pump unit for heating. This raises the temperature of the heat transfer medium above the preset temperature before it is delivered to the lithium bromide refrigeration unit for cooling. This alleviates the problem of large fluctuations in black water temperature, achieving a more stable heat output to the lithium bromide refrigeration unit and contributing to improved cooling stability. Furthermore, by raising the temperature of the low-temperature heat transfer medium through the heat pump, the previously unusable waste heat from the low-temperature black water is converted into a high-quality heat source usable by the lithium bromide refrigeration unit, reducing the waste of low-temperature black water waste heat.

[0019] 2. In a preferred embodiment of this application, by setting up a regenerative pipeline connecting the heat absorption end of the heat pump evaporator to the heat dissipation end of the lithium bromide refrigeration unit, the waste heat generated during the operation of the lithium bromide refrigeration unit can be recovered and utilized, and then transported to the heat pump evaporator as a heat source. Specifically, the heat pump evaporator contains refrigerant, which is in a low-temperature liquid state in the heat pump evaporator. The waste heat from the lithium bromide refrigeration unit heats the low-temperature liquid refrigerant through a heat exchanger, thereby evaporating it into a low-temperature, low-pressure gas. Then, the compressor of the heat pump unit, driven by electrical energy, compresses the low-temperature gas into a high-temperature, high-pressure gas. The high-temperature gas releases heat in the condenser to heat the heat transfer medium, and condenses itself into a high-pressure liquid. The high-pressure liquid is depressurized through an expansion valve and returns to the heat pump evaporator for re-absorption and circulation. That is, the role of the waste heat from the lithium bromide refrigeration unit is to preheat the refrigerant in the heat pump evaporator, increase its temperature, thereby reducing the compression energy consumption of the subsequent compressor and realizing the utilization of waste heat from the lithium bromide refrigeration unit.

[0020] 3. In a preferred embodiment of this application, the high-temperature pipeline delivers heat to the lithium bromide refrigeration unit via a second heat exchanger, while the low-temperature pipeline works in conjunction with the heat pump unit via a third heat exchanger, thereby increasing the heat exchange rate between the high-temperature and low-temperature pipelines. Furthermore, since the high-temperature and low-temperature pipelines are respectively connected to the first heat exchanger, the heat-conducting medium inside each pipeline heats the lithium bromide refrigeration unit and then circulates back into the first heat exchanger to absorb heat, thus achieving cyclic heating of the lithium bromide refrigeration unit.

[0021] 4. In a preferred embodiment of this application, the first water conveyance passage passes through the first heat exchanger and connects to the inlet of the coal chemical black water tower, guiding the heat-exchanged black water back to the coal chemical black water tower, forming a closed black water circulation system. This ensures that the black water remains in a closed loop throughout the entire treatment process, significantly improving the recycling efficiency of the black water, reducing the need for fresh water replenishment, and lowering the amount of black water treated, thus achieving the recycling of water resources. Furthermore, the closed loop also improves the safety and stability of the system, reduces the probability of external impurities entering the refrigeration system, thereby reducing the probability of equipment failure and making the system operation more reliable.

[0022] 5. As a preferred embodiment of this application, the design combining an external temperature sensor with a three-way solenoid valve enables relatively accurate monitoring of temperature changes in the heat transfer medium and rapid corresponding pipeline switching actions. The connection status between the water outlet and the high-temperature and low-temperature pipelines is adjusted according to the relative relationship between the heat transfer medium temperature and the preset temperature, thus optimizing the structural design of the refrigeration system.

[0023] 6. In a preferred embodiment of this application, the filtration unit pre-treats the black water entering the first heat exchanger, effectively intercepting solid particles and impurities in the black water and reducing the probability of these substances entering the first heat exchanger and causing blockage or wear. This reduces the cleaning and maintenance burden on the first heat exchanger, helps extend the service life of the refrigeration system, and improves the operational reliability of the refrigeration system. Attached Figure Description

[0024] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments of this application and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0025] Figure 1 This is a schematic diagram of a waste heat refrigeration system for black water from coal chemical industry according to one embodiment of this application;

[0026] Figure 2 This is a schematic diagram of a lithium bromide refrigeration unit and a heat pump unit according to one embodiment of this application.

[0027] List of components and reference numerals:

[0028] 1. Coal chemical black water tower;

[0029] 2. First heat exchanger;

[0030] 3 lithium bromide refrigeration units;

[0031] 4. First water conveyance route;

[0032] 5 Second water supply passage, 51 High temperature pipeline, 52 Low temperature pipeline;

[0033] 6 heat pump units;

[0034] 7. Second heat exchanger;

[0035] 8. Third heat exchanger;

[0036] 9. Water outlet pipes;

[0037] 10 temperature sensors;

[0038] 11 controllers;

[0039] 12-way solenoid valve;

[0040] 13 filter units;

[0041] 14. Pressure pump;

[0042] 15 heat return pipes. Detailed Implementation

[0043] To more clearly illustrate the overall concept of this application, a detailed explanation is provided below with reference to the accompanying drawings.

[0044] Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of this application is not limited to the specific embodiments disclosed below. It should be noted that, unless otherwise specified, the embodiments of this application and the features thereof can be combined with each other.

[0045] Furthermore, it should be understood in the description of this application that the terms "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application 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 this application.

[0046] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0047] In this application, unless otherwise expressly specified and limited, the "above" or "below" of the second feature can mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. In the description of this specification, references to terms such as "an embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples.

[0048] like Figure 1As shown, a waste heat refrigeration system for coal chemical black water includes a coal chemical black water tower 1, a first heat exchanger 2, a lithium bromide refrigeration unit 3, a first water supply passage 4 connecting the coal chemical black water tower 1 and the first heat exchanger 2, and a second water supply passage 5 connecting the first heat exchanger 2 and the lithium bromide refrigeration unit 3. The second water supply passage 5 is filled with a heat-conducting medium. The coal chemical black water tower 1 supplies black water to the first heat exchanger 2 through the first water supply passage 4 to heat the heat-conducting medium in the second water supply passage 5. The second water supply passage 5 includes a high-temperature pipe 51 and a low-temperature pipe 52. A temperature control valve assembly is provided at the outlet of the first heat exchanger 2. The temperature control valve assembly can... The high-temperature pipeline 51 and the low-temperature pipeline 52 are selectively connected to the water outlet. The temperature control valve group is set as follows: when the temperature of the heat transfer medium at the water outlet is ≥ the preset temperature, the high-temperature pipeline 51 is connected to the water outlet; when the temperature of the heat transfer medium at the water outlet is < the preset temperature, the low-temperature pipeline 52 is connected to the water outlet. The refrigeration system also includes a heat pump unit 6, which includes a heat pump evaporator, a compressor, a heat pump condenser, and an expansion valve. The heat release end of the heat pump condenser is connected to the low-temperature pipeline 52. The heat pump condenser can heat the heat transfer medium in the low-temperature pipeline 52 to ≥ the preset temperature and then deliver it to the generator of the lithium bromide refrigeration unit 3.

[0049] The black water waste heat cooling system of this application is equipped with a first heat exchanger 2, a first water supply passage 4, and a second water supply passage 5, realizing heat exchange between black water and a heat-conducting medium. This avoids the corrosion and blockage problems that may occur if black water directly enters the lithium bromide cooling system. The heat-conducting medium, as an intermediate heat transfer medium, can effectively isolate corrosive components and solid impurities in the black water, protecting the key components of the lithium bromide cooling unit 3 and helping to extend its service life. Secondly, the second water supply passage 5 includes a high-temperature pipe 51 and a low-temperature pipe 52, and is equipped with a temperature control valve assembly. When the black water temperature is high enough to provide sufficient heat to the heat transfer medium to reach a preset temperature or higher, the high-temperature pipe 51 connects to the outlet of the first heat exchanger 2 to transfer the heat transfer medium to the lithium bromide refrigeration unit 3. Conversely, when the black water temperature is insufficient to provide enough heat to the heat transfer medium, and the temperature of the heat transfer medium is below the preset temperature, the temperature control valve assembly controls the low-temperature pipe 52 to connect to the outlet of the first heat exchanger 2, transferring the low-temperature heat transfer medium to the heat pump unit 6 for heating, raising the heat transfer medium to above the preset temperature before it is delivered to the lithium bromide refrigeration unit 3 for cooling. In this way, the problem of large fluctuations in black water temperature is alleviated, and a more stable heat output to the lithium bromide refrigeration unit 3 is achieved, which helps to improve the cooling stability of the lithium bromide refrigeration unit 3. Furthermore, by using a heat pump to raise the temperature of the low-temperature heat transfer medium, the previously unusable low-temperature black water waste heat is converted into a high-quality heat source that can be used by the lithium bromide refrigeration unit 3, thus reducing the waste of low-temperature black water waste heat.

[0050] Preferably, the lithium bromide refrigeration unit 3 is connected to the air conditioning terminal equipment, and the cold air it produces is delivered to the air conditioning terminal equipment.

[0051] The working principle of the lithium bromide refrigeration unit 3 is as follows: Based on the properties of lithium bromide solution, which has strong hygroscopic properties, it can absorb water vapor and release heat. In the lithium bromide refrigeration unit 3, heat is transferred from the second water supply channel to the generator, heating the lithium bromide solution and causing the water in it to evaporate, forming water vapor. The water vapor enters the condenser of the lithium bromide refrigeration unit 3 and is condensed into liquid water by cooling water. The liquid water enters the evaporator of the lithium bromide refrigeration unit 3, evaporates under low pressure, absorbs heat, and produces a cooling effect. The evaporated water vapor is absorbed by the concentrated lithium bromide solution, reforming the dilute solution and completing the cycle, thus achieving heat absorption and refrigeration.

[0052] This application does not limit the type of heat transfer medium, but organic heat transfer oil, high-pressure water, etc. are preferred heat transfer media.

[0053] Preferably, a booster pump 14 is provided in the first water conveying passage 4, the high-temperature pipeline 51 and the low-temperature pipeline 52 respectively, for pumping black water or heat transfer medium in the pipeline.

[0054] As a preferred embodiment of this application, such as Figure 1 , Figure 2 As shown, the refrigeration system also includes a regenerative pipe 15 that connects the heat absorption end of the heat pump evaporator to the heat dissipation end of the lithium bromide refrigeration unit 3. The lithium bromide refrigeration unit 3 transfers heat to the heat pump evaporator through the regenerative pipe 15.

[0055] Specifically, Figure 2 In this diagram, a1 refers to the generator of lithium bromide refrigeration unit 3, b1 refers to the condenser of lithium bromide refrigeration unit 3, c1 refers to the evaporator of lithium bromide refrigeration unit 3, and d1 refers to the absorber of lithium bromide refrigeration unit 3; a2 refers to the evaporator of heat pump unit 6, b2 refers to the compressor of heat pump unit 6, c2 refers to the condenser of heat pump unit 6, and d2 refers to the expansion valve of heat pump unit 6. The heat generated during the condensation process of the condenser of lithium bromide refrigeration unit 3 is transferred to the evaporator of heat pump unit 6 through a heat exchanger to preheat the working fluid of heat pump unit 3.

[0056] By setting up a heat recovery pipe 15 connecting the heat absorption end of the heat pump evaporator to the heat dissipation end of the lithium bromide refrigeration unit 3, the waste heat generated during the operation of the lithium bromide refrigeration unit 3 can be recovered and utilized, and then transported to the heat pump evaporator as a heat source. Specifically, the heat pump evaporator contains refrigerant, which is in a low-temperature liquid state in the heat pump evaporator. The waste heat of the lithium bromide refrigeration unit 3 heats the low-temperature liquid refrigerant through a heat exchanger, thereby evaporating it into a low-temperature, low-pressure gas. Then, the compressor of the heat pump unit 6, driven by electric energy, compresses the low-temperature gas into a high-temperature, high-pressure gas. The high-temperature gas releases heat in the condenser to heat the heat transfer medium, and condenses itself into a high-pressure liquid. The high-pressure liquid is depressurized through an expansion valve and returns to the heat pump evaporator for re-absorption and circulation. In other words, the waste heat of the lithium bromide refrigeration unit 3 serves to preheat the refrigerant in the heat pump evaporator, raising its temperature, thereby reducing the compression energy consumption of the subsequent compressor and realizing the utilization of waste heat from the lithium bromide refrigeration unit 3.

[0057] As a preferred embodiment of this application, such as Figure 1 As shown, the refrigeration system also includes a second heat exchanger 7 and a third heat exchanger 8. The high-temperature pipeline 51 delivers heat to the generator of the lithium bromide refrigeration unit 3 through the second heat exchanger 7, and the low-temperature pipeline 52 delivers heat to the generator of the lithium bromide refrigeration unit 3 through the third heat exchanger 8. The high-temperature pipeline 51 passes through the second heat exchanger 7 and is connected to the inlet of the first heat exchanger 2. The low-temperature pipeline 52 passes through the heat pump unit 6 and the third heat exchanger 8 in sequence and is connected to the inlet of the first heat exchanger 2.

[0058] The high-temperature pipe 51 transfers heat to the lithium bromide refrigeration unit 3 through the second heat exchanger 7, while the low-temperature pipe 52 works in conjunction with the heat pump unit 6 through the third heat exchanger 8, thereby increasing the heat exchange rate between the high-temperature pipe 51 and the low-temperature pipe 52. Furthermore, since the high-temperature pipe 51 and the low-temperature pipe 52 are respectively connected to the first heat exchanger 2, the heat-conducting medium inside them heats the lithium bromide refrigeration unit 3 and then circulates back into the first heat exchanger 2 to absorb heat, thus achieving cyclic heating of the lithium bromide refrigeration unit 3.

[0059] As a preferred embodiment of this application, such as Figure 1 As shown, the first water conveyance passage 4 passes through the first heat exchanger 2 and is connected to the inlet of the coal chemical black water tower 1.

[0060] The first water conveyance channel 4 passes through the first heat exchanger 2 and connects to the inlet of the coal chemical black water tower 1, guiding the heat-exchanged black water back to the coal chemical black water tower 1, forming a closed black water circulation system. This ensures that the black water remains in a closed loop throughout the entire treatment process, significantly improving the recycling efficiency of the black water, reducing the need for fresh water replenishment, and lowering the amount of black water treated, thus achieving the recycling of water resources. Furthermore, the closed loop also improves the system's safety and stability, reducing the probability of external impurities entering the refrigeration system, thereby reducing the probability of equipment failure and making the system operation more reliable.

[0061] Preferably, a spray tower is provided between the first water conveying passage 4 and the inlet of the coal chemical black water tower 1 to cool the black water in the first water conveying passage 4, and the cooled black water is then transported to the coal chemical black water tower 1.

[0062] As a preferred embodiment of this application, such as Figure 1 As shown, the refrigeration system also includes an outlet pipe 9 that connects the outlet end to the second water supply passage 5. The temperature control valve group includes a temperature sensor 10 installed on the outer wall of the outlet pipe 9, a controller 11, and a three-way solenoid valve 12. The inlet of the three-way solenoid valve 12 is connected to the outlet pipe 9, and the two outlets of the three-way solenoid valve 12 are connected to the high-temperature pipeline 51 and the low-temperature pipeline 52, respectively. The controller 11 controls one of the outlets of the three-way solenoid valve 12 to open according to the monitoring signal of the temperature sensor 10.

[0063] By combining an external temperature sensor 10 with a three-way solenoid valve 12, the design can accurately monitor the temperature changes of the heat transfer medium and quickly switch pipelines accordingly. The connection between the water outlet and the high-temperature pipeline 51 and the low-temperature pipeline 52 is adjusted based on the relative relationship between the heat transfer medium temperature and the preset temperature, thus optimizing the structural design of the refrigeration system.

[0064] As a preferred embodiment of this application, such as Figure 1 As shown, the refrigeration system also includes a filter unit 13 located between the coal chemical black water tower 1 and the first heat exchanger 2. The filter unit 13 can filter black water impurities in the first water conveying passage 4 and transmit the filtered black water to the first heat exchanger 2 through the first water conveying passage 4.

[0065] The filter unit 13 pre-treats the black water entering the first heat exchanger 2, effectively intercepting solid particles and impurities in the black water and reducing the probability of these substances entering the first heat exchanger 2 and causing blockage or wear. This reduces the cleaning and maintenance burden on the first heat exchanger 2, helps extend the service life of the refrigeration system, and improves the operational reliability of the refrigeration system.

[0066] In a preferred embodiment of this application, the preset temperature is 80°C.

[0067] This temperature setting ensures both the efficient and stable operation of the lithium bromide refrigeration unit 3 and the full utilization of the waste heat resources of the black water. The operating temperature of 80℃ allows the heat pump unit 6 to operate within its optimal efficiency range, maximizing energy conversion efficiency. This temperature setting also fully considers the temperature distribution characteristics of black water from coal chemical processes, enabling the system to maintain stable operation under most conditions. Furthermore, this operating temperature helps extend the equipment's lifespan and avoids accelerated material aging caused by excessively high temperatures.

[0068] In a preferred embodiment of this application, the first heat exchanger 2 has a heat inlet passage that is connected to the first water supply passage 4, and the inner wall of the heat inlet passage is provided with an anti-corrosion layer.

[0069] Since black water may contain acidic or highly corrosive substances, which may damage the first heat exchanger 2, the application of the anti-corrosion layer protects the first heat exchanger 2 from the corrosive components in the black water as much as possible, and significantly extends the service life of the first heat exchanger 2.

[0070] Preferably, along the black water flow path, a first filter screen and a second filter screen are sequentially provided in the heat inlet passage, which are detachably connected to the first heat exchanger 2. The pore size of the first filter screen is larger than that of the second filter screen.

[0071] The first and second filters employ different pore sizes, enabling graded filtration of particles of varying sizes in the black water. This ensures effective filtration while optimizing flow performance, sequentially separating large and small solid waste particles from the black water, thus reducing the probability of blockage in the heat inlet passage. The detachable design makes maintenance and replacement of the first and second filters more convenient, significantly simplifying the daily maintenance of the first heat exchanger 2.

[0072] For any parts not mentioned in this application, existing technologies may be used or referenced.

[0073] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0074] The above description is merely an embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of this application should be included within the scope of the claims of this application.

Claims

1. A waste heat refrigeration system for black water from coal chemical industry, characterized in that, The system includes a coal chemical black water tower, a first heat exchanger, a lithium bromide refrigeration unit, a first water supply passage connecting the coal chemical black water tower and the first heat exchanger, and a second water supply passage connecting the first heat exchanger and the lithium bromide refrigeration unit. The second water supply passage is filled with a heat-conducting medium. The coal chemical black water tower supplies black water to the first heat exchanger through the first water supply passage to heat the heat-conducting medium in the second water supply passage. The second water supply path includes a high-temperature pipeline and a low-temperature pipeline. A temperature control valve assembly is installed at the outlet of the first heat exchanger. This temperature control valve assembly can selectively connect either the high-temperature pipeline or the low-temperature pipeline to the outlet. The temperature control valve assembly is configured as follows: When the temperature of the heat-conducting medium at the water outlet is greater than or equal to the preset temperature, the high-temperature pipeline is connected to the water outlet. When the temperature of the heat-conducting medium at the water outlet is less than the preset temperature, the low-temperature pipeline is connected to the water outlet. The refrigeration system also includes a heat pump unit, which includes a heat pump evaporator, a compressor, a heat pump condenser, and an expansion valve. The heat release end of the heat pump condenser is connected to the low-temperature pipeline. The heat pump condenser can heat the heat transfer medium in the low-temperature pipeline to a temperature ≥ a preset temperature and then deliver it to the generator of the lithium bromide refrigeration unit.

2. The waste heat refrigeration system for black water from coal chemical industry according to claim 1, characterized in that, The refrigeration system further includes a regenerative pipeline connecting the heat absorption end of the heat pump evaporator to the heat dissipation end of the lithium bromide refrigeration unit, and the lithium bromide refrigeration unit delivers heat to the heat pump evaporator through the regenerative pipeline.

3. The waste heat refrigeration system for black water from coal chemical industry according to claim 1, characterized in that, The refrigeration system further includes a second heat exchanger and a third heat exchanger. The high-temperature pipeline delivers heat to the generator of the lithium bromide refrigeration unit through the second heat exchanger, and the low-temperature pipeline delivers heat to the generator of the lithium bromide refrigeration unit through the third heat exchanger. The high-temperature pipeline passes through the second heat exchanger and is connected to the inlet of the first heat exchanger. The low-temperature pipeline passes through the heat pump unit and the third heat exchanger in sequence and is connected to the inlet of the first heat exchanger.

4. The waste heat refrigeration system for black water from coal chemical industry according to claim 1, characterized in that, The first water conveyance passage passes through the first heat exchanger and is connected to the inlet of the coal chemical black water tower.

5. The waste heat refrigeration system for black water from coal chemical industry according to claim 1, characterized in that, The refrigeration system further includes an outlet pipe that connects the outlet end to the second water supply passage. The temperature control valve group includes a temperature sensor installed on the outer wall of the outlet pipe, a controller, and a three-way solenoid valve. The inlet of the three-way solenoid valve is connected to the outlet pipe, and the two outlets of the three-way solenoid valve are respectively connected to the high-temperature pipeline and the low-temperature pipeline. The controller controls one of the outlets of the three-way solenoid valve to open according to the monitoring signal of the temperature sensor.

6. The waste heat refrigeration system for black water from coal chemical industry according to claim 1, characterized in that, The refrigeration system also includes a filtration unit located between the coal chemical black water tower and the first heat exchanger. The filtration unit is capable of filtering black water impurities in the first water supply path and transmitting the filtered black water to the first heat exchanger through the first water supply path.

7. The waste heat refrigeration system for black water from coal chemical industry according to claim 1, characterized in that, The preset temperature is 80℃.

8. The waste heat refrigeration system for black water from coal chemical industry according to claim 1, characterized in that, The first heat exchanger has a heat inlet passage that is connected to the first water supply passage, and the inner wall of the heat inlet passage is provided with an anti-corrosion layer.

9. The waste heat refrigeration system for coal chemical black water according to claim 8, characterized in that, Along the black water flow path, a first filter screen and a second filter screen are sequentially provided in the heat inlet passage, which are detachably connected to the first heat exchanger. The pore size of the first filter screen is larger than that of the second filter screen.

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