MAR wastewater low temperature evaporation concentration system

Abstract

The utility model discloses a MAR wastewater low temperature evaporation concentration system, including evaporating tank, heating assembly and heat exchange component, heating assembly includes heater and compressor, heat exchange component includes pre -cooler and heat exchanger A, the secondary steam that wastewater enters evaporating tank and evaporates, and the heat exchanger A is entered after pre -cooler cooling, and the condensed discharge after heat exchange with the medium in heat exchanger A, and the medium in heat exchanger A is transported to compressor after absorbing secondary steam heat and heating, and the secondary heating is entered heater and wastewater heat exchange after compressor compression, and the heat exchanger A is flowed back after cooling through the first expansion valve pressure reduction cooling, and the closed loop circulation is formed, and wastewater and heating medium heat exchange process heat up, and form concentrated liquid and discharge from concentrated liquid export in evaporating tank and evaporate. The utility model discloses a heat exchange component is arranged, realizes the recycling of secondary steam heat, and the heat of secondary steam is given heating medium, and the medium of carrying heat enters compressor, and the energy consumption is reduced, and the heat efficiency of system is improved.

Description

Technical Field

[0001] This utility model relates to the field of wastewater or sewage treatment technology, and in particular to a low-temperature evaporation and concentration system for wastewater based on mechanical air recompression (MAR) technology. Background Technology

[0002] The working principle of a traditional low-temperature wastewater evaporation system is as follows: wastewater is introduced into a distillation kettle through a vacuum system and evaporates into steam under low pressure. After purification, the steam enters a condenser, exchanges heat with circulating cooling water, and condenses into liquid water, which is finally collected in a buffer tank. However, the heat energy released during wastewater evaporation is not effectively recovered and utilized, resulting in energy waste. Summary of the Invention

[0003] To overcome the above-mentioned defects, this utility model provides a low-temperature evaporation and concentration system for MAR wastewater to reduce energy consumption and improve treatment efficiency.

[0004] The technical solution adopted by this utility model to solve its technical problem is as follows: a low-temperature evaporation and concentration system for MAR wastewater is provided, including an evaporator, a heating component, and a heat exchange component; the evaporator is provided with a wastewater inlet and a concentrate outlet; the heating component includes a heater for heating wastewater and a compressor for supplying a medium to the heater; the heat exchange component includes a precooler communicating with the inner cavity of the evaporator and a heat exchanger A disposed between the precooler and the compressor; The wastewater enters the evaporator and evaporates to generate secondary steam. This steam is then cooled by the precooler and enters the heat exchanger A. After exchanging heat with the medium in the heat exchanger A, the steam is condensed and discharged. The medium in the heat exchanger A absorbs the heat from the secondary steam and is heated. It is then sent to the compressor, where it is compressed and heated again before entering the heater to exchange heat with the wastewater. After cooling, the medium is depressurized and cooled by the first expansion valve and flows back to the heat exchanger A, forming a closed-loop cycle. During the heat exchange process between the wastewater and the heating medium, the wastewater is heated and evaporates in the evaporator to form a concentrated liquid, which is discharged from the concentrated liquid outlet.

[0005] As a further improvement of this utility model, the heater is a heating coil installed in the evaporator. The heating coil is composed of multiple horizontally placed U-shaped tubes spaced apart from the inside to the outside. The ports of the multiple U-shaped tubes are connected to a manifold. The manifold is provided with a high-temperature medium inlet A connected to the compressor and a low-temperature medium outlet A connected to the heat exchanger A through the first expansion valve.

[0006] As a further improvement of this utility model, a second expansion valve is provided on the pipeline connecting the compressor to the high-temperature medium inlet A.

[0007] As a further improvement of this utility model, the heater is a wastewater circulation heater located outside the evaporator. The wastewater circulation heater includes a heat exchanger B and a circulation pump. The heat exchanger B includes a shell B for circulating medium and a heat exchange tube B located inside the shell B for circulating wastewater. The shell B is provided with a high-temperature medium inlet B connected to the compressor and a low-temperature medium outlet B connected to the heat exchanger A through a first expansion valve. The heat exchange tube B is connected to the evaporator through the circulation pump. After the wastewater is evaporated in the evaporator, it forms a circulating liquid. The circulating liquid exchanges heat with the medium in the heat exchange tube B in the heat exchanger B and is heated. Then it flows into the evaporator to be evaporated and circulates between the evaporator and the heat exchanger B to be concentrated step by step.

[0008] As a further improvement of this utility model, a filter for filtering crystal particles in the circulating liquid is provided between the heat exchanger B and the circulating pump.

[0009] As a further improvement of this utility model, the precooler includes a shell and a precooling pipe disposed in the shell. The two ends of the shell are respectively connected to the evaporator and the heat exchanger A through pipelines. The precooling pipe is arranged in a spiral shape in the shell and is circulated with cooling water.

[0010] As a further improvement of this utility model, the heat exchanger A includes a shell A and a heat exchange tube A disposed within the shell A. The inlet of the housing A is connected to the first expansion valve, and the outlet is connected to the compressor; the inlet of the heat exchange tube A is connected to the outlet of the housing, and the outlet of the heat exchange tube A extends outside the housing A to discharge the condensate generated after the secondary steam heat exchange.

[0011] As a further improvement of this utility model, the precooler is arranged horizontally or vertically.

[0012] As a further improvement of this utility model, the secondary steam generated in the evaporator at 35 to 40°C is cooled to 28 to 32°C and condensed and discharged after exchanging heat with the medium in the heat exchange component, while the medium is heated to 28 to 32°C and supplied to the compressor.

[0013] As a further improvement of this utility model, the evaporator is placed horizontally, and a lid that can seal the opening is hinged at the top of the tank; the wastewater inlet is located close to the opening of the tank. Meanwhile, an orifice plate for dispersing wastewater is provided below the wastewater inlet inside the evaporator.

[0014] The beneficial effects of this utility model are: by setting up heat exchange components, the heat of secondary steam can be recovered and utilized, and the heat of secondary steam can be transferred to the heating medium, so that the heat-carrying medium enters the compressor, thereby reducing energy consumption and improving the thermal efficiency of the system. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the concentration system structure according to Embodiment 1 of this utility model; Figure 2 This is a schematic diagram of the evaporator structure according to Embodiment 1 of this utility model; Figure 3 This is a schematic diagram showing the layout of each component in Embodiment 1 of this utility model; Figure 4 This is a front view and a cross-sectional view along the AA direction of Embodiment 1 of this utility model; Figure 5 This is a schematic diagram of Embodiment 2 of the present invention.

[0016] Referring to the accompanying drawings, the following explanations are provided: 1. Evaporator; 10. Wastewater Inlet; 11. Concentrate Outlet; 12. Tank Cover; 13. Orifice Plate; 14. Flip-top Clamping Mechanism; 2. Heating Assembly; 21. Compressor; 22. Heating Coil; 221. U-tube; 222. Manifold; 2221. High-Temperature Medium Inlet A; 2222. Low-Temperature Medium Outlet A; 23. Wastewater Circulation Heater; 231. Heat Exchanger B; 2311. Shell B; 23111. High-Temperature Medium Inlet B; 2312. Heat Exchanger Tube B; 23112. Low-Temperature Medium Outlet B; 232. Circulation Pump; 233. Filter; 3. Heat Exchange Assembly; 31. Precooler; 311. Tube Shell; 312. Precooling Tube; 32. Heat Exchanger A; 321. Shell A; 322. Heat Exchanger Tube A; 3221. Condensate Drain; 4. First Expansion Valve; 5. Second Expansion Valve. Detailed Implementation

[0017] The preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

[0018] First, it should be noted that this application incorporates a vacuum system (not shown in the figure) at the bottom of the evaporator. This system creates a vacuum environment of -93 kPa to -98 kPa within the evaporator, utilizing the pressure difference effect to automatically draw in wastewater. Under high vacuum conditions, the wastewater only needs to be heated to approximately 40°C to reach its boiling point and begin evaporation. It should be noted that the aforementioned vacuum evaporation principle is a conventional technique in this field; the focus of this application is on innovative structural design, therefore, this basic process will not be described in detail.

[0019] The MAR wastewater low-temperature evaporation and concentration system provided in this application is used for evaporating and concentrating wastewater at low temperatures. It includes an evaporator tank 1, a heating assembly 2, and a heat exchange assembly 3. (See attached document) Figure 1This application, through integrated design and compact layout of components, enables the rapid and efficient assembly, disassembly, installation and debugging of the system, effectively improving the overall operating efficiency and maintainability of the system.

[0020] The evaporator 1 is equipped with a wastewater inlet 10 and a concentrate outlet 11. The heating assembly 2 includes a heater for heating the wastewater and a compressor 21 for supplying the heating medium. The heat exchange assembly 3 includes a precooler 31 connected to the inner cavity of the evaporator 1 and a heat exchanger A32 located between the precooler 31 and the compressor 21. The evaporator 1 provides a sealed, low-pressure environment with an internal pressure of 0.03–0.04 MPa. Under this environment, the boiling point of the wastewater is lowered, allowing evaporation without high temperatures. The heating assembly heats the wastewater entering the evaporator to approximately 40°C, causing it to evaporate at this temperature, thereby achieving wastewater concentration. The heat exchange assembly contributes to energy conservation and reduced consumption in the system.

[0021] Specifically, the secondary steam generated by the evaporation of wastewater in the evaporator 1 is cooled by the precooler 31 and enters the heat exchanger A32. After exchanging heat with the medium in the heat exchanger A32, it is condensed and discharged. The medium in the heat exchanger A32 absorbs the heat of the secondary steam and is heated. It is then sent to the compressor 21, where it is compressed and heated again before entering the heater to exchange heat with the wastewater. After cooling, it is depressurized and cooled by the first expansion valve 4 and flows back to the heat exchanger A32, forming a closed loop. During the heat exchange process between the wastewater and the heating medium, the wastewater is heated and evaporated in the evaporator 1 to form a concentrated liquid, which is discharged from the concentrated liquid outlet 11.

[0022] In other words, the medium inside the heating element cools down after exchanging heat with the wastewater. The heat exchange component then uses secondary steam to exchange heat with the cooled medium, raising its temperature before it enters the compressor. Because the medium entering the compressor is at a higher temperature, the compressor's energy consumption is reduced, lowering equipment operating costs. Simultaneously, effective heat recovery and utilization further reduce the overall system's energy consumption and improve its energy efficiency.

[0023] See Figures 1 to 4 Embodiment 1 provided by this utility model.

[0024] The evaporator 1 is horizontally positioned, with a lid 12 hinged to its top opening for sealing. A wastewater inlet 10 is located near the opening. The lid 12 is automatically opened and closed via a flip-top clamping mechanism 14. Additionally, a concentrate outlet 24 for discharging concentrated liquid is located on the side of the evaporator 1, and a wastewater inlet 23 is connected to a wastewater supply device (not shown in the diagram). The evaporator 1 features a top-opening structure, facilitating subsequent cleaning and maintenance of the tank's interior. A perforated plate 13 is installed below the wastewater inlet 10 inside the evaporator 1 to disperse the wastewater. When wastewater enters the evaporator 1 from the wastewater inlet 10, it is first dispersed into a water mist by the perforated plate 13, thereby increasing the heat exchange area between the wastewater and the tank interior, promoting evaporation, and improving evaporation efficiency.

[0025] The heater is a heating coil 22 located inside the evaporator 1. The heating coil 22 consists of multiple horizontally placed U-shaped tubes 221 spaced apart from the inside out. The ports of the multiple U-shaped tubes 221 are connected to a manifold 222. The manifold 222 has a high-temperature medium inlet A2221 connected to the compressor 21 and a low-temperature medium outlet A2222 connected to the heat exchanger A32 through the first expansion valve 4. It can automatically adjust the flow rate and pressure of the medium according to the system's operating parameters, improving the system's operating efficiency and stability. In addition, the heating coil 22, composed of multiple U-shaped tubes 221, not only increases the total length of the heating tubes within a limited space, providing a larger heating surface area and improving heating efficiency, but also integrates multiple U-shaped tubes 221 into the manifold 222, making installation relatively simple and allowing operators to easily disassemble and install them when replacement or maintenance is required.

[0026] Furthermore, the precooler 31 includes a shell 311 and a precooling pipe 312 disposed within the shell 311. The two ends of the shell 311 are respectively connected to the evaporator 2 and the heat exchanger A32 via pipelines. The precooling pipe 312 is arranged in a spiral shape within the shell 311 and is circulated with cooling water. The heat exchanger A32 includes a shell A321 and a heat exchange pipe A322 disposed within the shell A321. The inlet of the shell A321 is connected to the first expansion valve 4, and the outlet is connected to the compressor 21. The inlet of the heat exchange pipe A322 is connected to the outlet of the shell 311, and the outlet of the heat exchange pipe A322 extends outside the shell A321 to discharge the condensate generated after the secondary steam heat exchange.

[0027] Specifically, after the wastewater enters the evaporator 2, it is evaporated to produce secondary steam at 37°C. This secondary steam then passes through the precooler 31 and exchanges heat with the circulating cooling water in the precooling pipe 312. The steam temperature is rapidly reduced to 30°C, achieving a thermal balance. The cooled steam then enters the heat exchanger A32, where it exchanges heat again with the medium returning to A32, raising the medium's temperature to 30°C. This not only avoids energy waste but also reduces the compressor's energy consumption. Actual testing and data analysis show that this energy utilization method improves efficiency by 20%, enhancing the economy and environmental friendliness of the entire wastewater concentration system. Simultaneously, the condensate from the liquefied steam is discharged from the condensate drain outlet 3211 at the bottom of the heat exchanger A32 and collected for further treatment.

[0028] In addition, a second expansion valve 5 is installed on the pipeline connecting the compressor 21 to the high-temperature medium inlet A2221 to throttle and reduce the pressure of the medium, so as to ensure that the medium entering the heater has a suitable pressure and temperature.

[0029] Furthermore, the precooler 31 can be configured horizontally or vertically to accommodate different installation spaces and process requirements. Horizontal configuration is suitable for large-scale concentration systems, where the internal precooling tubes 312 are arranged in a tubular configuration (similar to a heating tube assembly). Vertical configuration is suitable for small, lightweight concentration systems, where the internal precooling tubes 312 are arranged spirally within the tube shell 311.

[0030] Specifically, the 37°C secondary steam output from the evaporator is cooled to 30°C by the precooler 31 and enters the heat exchanger A32. Simultaneously, the compressor provides a 45°C high-temperature medium that enters the heating coil 22 through the high-temperature medium inlet A2221. After exchanging heat with the wastewater in the evaporator, the medium cools to 40°C, then is depressurized and cooled to 25°C by the first expansion valve 4 before entering the heat exchanger A32. There, it exchanges heat with the 30°C secondary steam and is heated to 30°C. The heated steam then enters the compressor, is compressed, and is heated to 45°C before entering the heating coil 22, forming a closed-loop circulation of the heating medium. This continuous heating of the wastewater achieves concentration. Furthermore, the secondary steam that has completed heat exchange in the heat exchanger A32 is cooled and discharged as condensate, achieving both heat recovery and convenient collection of condensate.

[0031] See Figure 5 and in conjunction with the appendix Figures 1 to 4 The schematic diagram of Embodiment 2 provided by this utility model.

[0032] The difference between Example 2 and Example 1 is that the heater is a wastewater circulation heater 23 located outside the evaporator 1. The wastewater circulation heater 23 includes a heat exchanger B231 and a circulation pump 232. The heat exchanger B231 includes a shell B2311 for circulating medium and a heat exchange tube B2312 located inside the shell B2311 for circulating wastewater. The shell B2311 has a high-temperature medium inlet B23111 connected to the compressor 21 and a low-temperature medium outlet B23112 connected to the heat exchanger A32 through the first expansion valve 4. The heat exchange tube B2312 is connected to the evaporator 1 through the circulation pump 232. The specific working process is as follows: after the wastewater evaporates in the evaporator 1, it forms a circulating liquid. The circulating liquid flows into the heat exchanger B231, where it exchanges heat with the medium in the heat exchange tube B2312, thereby achieving a temperature increase. The heated circulating liquid then flows back to the evaporator 1 to continue evaporating. In this way, the circulating liquid continuously circulates between evaporator 1 and heat exchanger B231, thereby achieving staged concentration.

[0033] Furthermore, a filter 233 is added between the heat exchanger B231 and the circulating pump 232 to filter out the salt crystals generated during the heating and circulation of the circulating liquid, ensuring smooth flow of the circulating liquid and stable operation of the system.

[0034] The MAR wastewater low-temperature evaporation and concentration system provided by this utility model achieves the recovery and utilization of secondary steam heat by setting up heat exchange components. The heat of the secondary steam is transferred to the heating medium, allowing the heat-carrying medium to enter the compressor, thereby reducing energy consumption and improving the system's thermal efficiency. The system adopts a reasonable structural design and workflow, enabling the wastewater to fully evaporate in the evaporator to form a high-concentration concentrate, effectively achieving wastewater reduction and resource utilization. In addition, the top of the evaporator is equipped with a sealable lid, facilitating inspection and maintenance of the evaporator's interior. The filter can filter out crystal particles in the circulating liquid, preventing equipment blockage, extending equipment life, and reducing operation and maintenance costs.

[0035] Many specific details have been set forth in the above description to provide a full understanding of this utility model. However, the above description is only a preferred embodiment of this utility model, and this utility model can be implemented in many other ways different from those described herein. Therefore, this utility model is not limited to the specific embodiments disclosed above. Furthermore, any person skilled in the art can make many possible variations and modifications to the technical solution of this utility model using the methods and techniques disclosed above, or modify it into equivalent embodiments with equivalent changes, without departing from the scope of the technical solution of this utility model. Any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this utility model, without departing from the content of the technical solution of this utility model, shall still fall within the protection scope of the technical solution of this utility model.

Claims

1. A low-temperature evaporation and concentration system for MAR wastewater, characterized in that, The system includes an evaporator (1), a heating assembly (2), and a heat exchange assembly (3). The evaporator (1) is provided with a wastewater inlet (10) and a concentrate outlet (11). The heating assembly (2) includes a heater for heating wastewater and a compressor (21) for supplying a medium to the heater. The heat exchange assembly (3) includes a precooler (31) communicating with the inner cavity of the evaporator (1) and a heat exchanger A (32) located between the precooler (31) and the compressor (21). The wastewater enters the evaporator (1) and evaporates to generate secondary steam. The secondary steam is cooled by the precooler (31) and enters the heat exchanger A (32). After exchanging heat with the medium in the heat exchanger A (32), the steam is condensed and discharged. The medium in the heat exchanger A (32) absorbs the heat of the secondary steam and is heated. It is then sent to the compressor (21). After being compressed by the compressor (21), the medium is heated again and enters the heater to exchange heat with the wastewater. After being cooled, the medium is depressurized and cooled by the first expansion valve (4) and flows back to the heat exchanger A (32), forming a closed loop. The wastewater is heated during the heat exchange with the heating medium and evaporates in the evaporator (1) to form a concentrated liquid, which is discharged from the concentrated liquid outlet (11).

2. The MAR wastewater low-temperature evaporation and concentration system according to claim 1, characterized in that: The heater is a heating coil (22) located in the evaporator (1). The heating coil (22) is composed of multiple horizontally placed U-shaped tubes (221) spaced apart from the inside to the outside. The ports of the multiple U-shaped tubes (221) are connected to a manifold (222). The manifold (222) is provided with a high-temperature medium inlet A (2221) connected to the compressor (21) and a low-temperature medium outlet A (2222) connected to the heat exchanger A (32) through the first expansion valve (4).

3. The MAR wastewater low-temperature evaporation and concentration system according to claim 2, characterized in that: The compressor (21) is connected to the pipeline of the high-temperature medium inlet A (2221) by a second expansion valve (5).

4. The MAR wastewater low-temperature evaporation and concentration system according to claim 1, characterized in that: The heater is a wastewater circulation heater (23) located outside the evaporator (1). The wastewater circulation heater (23) includes a heat exchanger B (231) and a circulation pump (232). The heat exchanger B (231) includes a shell B (2311) for circulating medium and a heat exchange tube B (2312) for circulating wastewater located inside the shell B (2311). The shell B (2311) is provided with a high-temperature medium inlet B (23111) connected to the compressor (21) and a pump that passes through the first An expansion valve (4) is connected to the low-temperature medium outlet B (23112) of the heat exchanger A (32); the heat exchange tube B (2312) is connected to the evaporator (1) through the circulation pump (232). The wastewater is evaporated in the evaporator (1) to form a circulating liquid. The circulating liquid exchanges heat with the medium in the heat exchange tube B (2312) in the heat exchanger B (231) and then flows into the evaporator (1) to be evaporated. It is then circulated between the evaporator (1) and the heat exchanger B (231) and concentrated step by step.

5. The MAR wastewater low-temperature evaporation and concentration system according to claim 4, characterized in that: A filter (233) for filtering crystals in the circulating liquid is provided between the heat exchanger B (231) and the circulating pump (232).

6. The MAR wastewater low-temperature evaporation and concentration system according to claim 3 or 5, characterized in that: The precooler (31) includes a shell (311) and a precooling pipe (312) disposed in the shell (311). The two ends of the shell (311) are respectively connected to the evaporator (1) and the heat exchanger A (32) through pipelines. The precooling pipe (312) is arranged in a spiral shape in the shell (311) and is circulated with cooling water.

7. The MAR wastewater low-temperature evaporation and concentration system according to claim 6, characterized in that: The heat exchanger A (32) includes a shell A (321) and a heat exchange tube A (322) disposed in the shell A (321). The inlet of the housing A (321) is connected to the first expansion valve (4), and the outlet is connected to the compressor (21); the inlet of the heat exchange tube A (322) is connected to the outlet of the tube shell (311), and the outlet of the heat exchange tube A (322) extends to the outside of the housing A (321) to discharge the condensate generated after the secondary steam heat exchange.

8. The MAR wastewater low-temperature evaporation and concentration system according to claim 6, characterized in that: The precooler (31) is arranged horizontally or vertically.

9. The MAR wastewater low-temperature evaporation and concentration system according to claim 1, characterized in that: The secondary steam generated in the evaporator (1) at 35 to 40°C is cooled to 28 to 32°C and condensed and discharged after exchanging heat with the medium in the heat exchange component (3), while the medium is heated to 28 to 32°C and supplied to the compressor (21).

10. The MAR wastewater low-temperature evaporation and concentration system according to claim 1, characterized in that: The evaporator (1) is placed horizontally, and a lid (12) that can seal the opening of the tank is hinged at the top of the tank opening; the wastewater inlet (10) is located close to the opening of the tank. Meanwhile, an orifice plate (13) for dispersing wastewater is provided inside the evaporator (1) near the bottom of the wastewater inlet (10).

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