Solvent-containing wastewater treatment system

Abstract

The invention provides a treatment system for solvent-containing wastewater, and belongs to the technical field of wastewater treatment.The treatment system for the solvent-containing wastewater comprises an evaporator, a separation tank, a rectifying tower and a phase splitting tank, the separation tank is provided with a first cavity and a second cavity, and wastewater enters the evaporator; gas flowing out of the first gas phase outlet in the evaporator enters the rectifying tower, liquid flowing out of the first liquid phase outlet enters the first chamber, and liquid in the separation tank enters the rectifying tower through the second gas phase outlet after being evaporated; liquid flowing out of the rectifying tower enters the second chamber through the second liquid phase outlet, liquid in the second chamber flows back to the evaporator, gas generated by the rectifying tower enters the phase separation tank through the third gas phase outlet, and the phase separation tank is used for condensing the gas, separating water and enabling the water to flow back to the top of the rectifying tower. In this way, a reusable light phase is formed.

Description

Technical Field

[0001] The invention belongs to the technical field of wastewater treatment, and in particular relates to a treatment system for solvent-containing wastewater. Background Art

[0002] In the pharmaceutical industry, solvents are widely used in various processes such as reactions and extractions. Common solvents include butyl acetate, butanol, dichloromethane, methanol, toluene, and acetone. These solvents are often consumed in large quantities. To reduce production costs and pollutant emissions, recycling and reuse are important aspects of the industry.

[0003] Solvent recovery processes include extractive distillation, azeotropic distillation, conventional distillation, extraction, reaction, and membrane filtration. The appropriate process is selected based on the physical properties of the waste solvent or solvent-wastewater system. For example, the ternary azeotropic system of vinyl acetate, butanol, and water is more suitable for separation using azeotropic distillation, while methanol-water or acetone-water systems can be separated using conventional distillation. Solvent recovery processes must meet wastewater discharge standards, solvent recovery rate, purity, and other requirements while also controlling energy consumption.

[0004] Waste solvents often have complex compositions and contain many trace impurities, such as acids, alkalis, heat-sensitive substances or particulate matter. These impurities sometimes have a significant impact on the recycling process, making it prone to problems such as corrosion, blockage, discoloration, and reduced heat exchanger efficiency.

[0005] Common recovery methods mainly include atmospheric distillation and vacuum distillation. These process solutions can only handle waste solvents with relatively clean composition. For those materials with complex composition, solid content or viscosity, tower blockage, inability to operate normally, and substandard products are prone to occur. Summary of the Invention

[0006] The embodiment of the present invention provides a system for treating solvent-containing wastewater, aiming to solve the technical problems of easy tower blockage, abnormal operation and substandard products in the existing solvent recovery process.

[0007] To achieve the above object, the technical solution adopted by the present invention is to provide a treatment system for solvent-containing wastewater, comprising: an evaporator having a first gas phase outlet and a first liquid phase outlet; a separation tank having a first chamber, a second chamber, and a second gas phase outlet, wherein the first chamber is connected to the first liquid phase outlet, and the liquid in the second chamber is used to flow back to the evaporator; a distillation tower having a second liquid phase outlet and a third gas phase outlet, the distillation tower being in communication with the first gas phase outlet and the second gas phase outlet, and the second liquid phase outlet being in communication with the second chamber; a phase separation tank, connected to the third gas phase outlet, for separating the water phase and flowing the water phase back to the top of the distillation tower; Among them, wastewater enters the evaporator, the gas flowing out of the first gas phase outlet in the evaporator enters the distillation tower, the liquid flowing out of the first liquid phase outlet enters the first chamber, the liquid in the separation tank evaporates and enters the distillation tower through the second gas phase outlet, the liquid flowing out of the distillation tower enters the second chamber through the second liquid phase outlet, the liquid in the second chamber flows back to the evaporator, the gas generated by the distillation tower enters the phase separation tank through the third gas phase outlet, the phase separation tank is used to condense the gas and separate the water and flow it back to the top of the distillation tower to form a reusable light phase.

[0008] In one possible implementation, the separation tank includes: Tank; a partition fixedly disposed in the tank body, wherein opposite sides of the partition form the first chamber and the second chamber, and a top of the partition is spaced from an inner wall of the tank body so that the liquid in the first chamber can overflow into the second chamber; A steam drum is provided at the top of the tank body, and a gas outlet of the steam drum forms the second gas phase outlet.

[0009] In a possible implementation, a first external discharge pipe communicating with the first chamber is provided at the bottom of the tank.

[0010] In a possible implementation, the evaporator is a scraped falling film evaporator.

[0011] In a possible implementation, a condenser is further provided between the third gas phase outlet and the phase separation tank.

[0012] In a possible implementation, the phase separation tank has a fourth gas phase outlet, and the solvent-containing wastewater treatment system further includes a vacuum pump connected to the fourth gas phase outlet.

[0013] In a possible implementation, a second external pipe is provided at the bottom of the distillation tower.

[0014] In a possible implementation, a liquid transmitter is provided on the outside of the distillation tower, and both the liquid inlet side and the liquid outlet side of the liquid transmitter are in communication with the distillation tower.

[0015] In a possible implementation, a power pump is provided between the second chamber and the evaporator, and between the phase separation tank and the distillation tower.

[0016] In a possible implementation, the distillation tower is further provided with a temperature transmitter and a pressure transmitter.

[0017] In the embodiments of the present application, compared with the prior art, the treatment system for solvent-containing wastewater of the present application utilizes a separation tank to enrich particulate matter and penicillin metabolites in a first chamber, and can be cleaned after enrichment for a period of time to prevent them from entering the distillation tower, thereby preventing tower plate blockage; the evaporator is utilized to vaporize a large amount of solvent components in the wastewater, and the decomposition and discoloration of penicillin metabolites are effectively suppressed, and the higher the vaporization rate of the evaporator and the greater the flow rate, the lower the butyl acetate content in the distillation tower wastewater, but the process operating conditions and energy consumption of the evaporator must be considered; the entire treatment system can work intermittently (the evaporator treats a certain amount of wastewater before proceeding to the next treatment) or continuously (the wastewater is continuously treated by the evaporator) to meet different production needs, and has the characteristics of not destroying heat-sensitive components, low energy consumption, and high solvent recovery rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a process flow chart of a system for treating solvent-containing wastewater provided by an embodiment of the present invention.

[0019] Description of reference numerals: 10-evaporator; 11-first gas phase outlet; 12-first liquid phase outlet; 20-separation tank; 21-tank body; 22-partition plate; 23-steam drum; 24-first chamber; 25-second chamber; 26-second gas phase outlet; 27-first external discharge pipe; 30-distillation tower; 31-second liquid phase outlet; 32-third gas phase outlet; 33-second external exhaust pipe; 34-liquid transmitter; 35-temperature transmitter; 36-pressure transmitter; 40-phase separation tank; 41-fourth gas phase outlet; 50-condenser; 60-vacuum pump; 70-Power pump. DETAILED DESCRIPTION

[0020] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0021] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0022] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0023] Unless otherwise specified, the relative arrangement of the parts and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present application. Meanwhile, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to actual proportional relationships. Technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments can have different values. It should be noted that similar numbers and letters represent similar items in the following drawings, and therefore, once an item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0024] In the description of this application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "horizontal, vertical, vertical, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of this application; the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0025] For ease of description, spatially relative terms such as "above", "on the upper surface of", "upper", etc. may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figures. For example, if the device in the figures is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be subsequently positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both the orientations of "above" and "below". The device may also be positioned in other different ways, and the spatially relative descriptions used herein shall be interpreted accordingly.

[0026] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0027] Please also refer to Figure 1 , the treatment system of solvent-containing wastewater provided by the present invention is now described. The treatment system of solvent-containing wastewater includes an evaporator 10, a separator 20, a distillation tower 30, and a phase-separation tank 40. The evaporator 10 has a first gas phase outlet 11 and a first liquid phase outlet 12; the separator 20 has a first chamber 24, a second chamber 25, and a second gas phase outlet 26. The first chamber 24 is connected to the first liquid phase outlet 12, and the liquid in the second chamber 25 is used to flow back to the evaporator 10; the distillation tower 30 has a second liquid phase outlet 31 and a third gas phase outlet 32. The distillation tower 30 is connected to the first gas phase outlet 11 and the second gas phase outlet 26, and the second liquid phase outlet 31 is connected to the second chamber 25; the phase-separation tank 40 is connected to the third gas phase outlet 32, and the phase-separation tank 40 is used to separate the water phase and flow it back to the top of the distillation tower 30; Among them, the wastewater enters the evaporator 10, the gas flowing out of the first gas phase outlet 11 in the evaporator 10 enters the distillation tower 30, the liquid flowing out of the first liquid phase outlet 12 enters the first chamber 24, and the liquid in the separation tank 20 evaporates and enters the distillation tower 30 through the second gas phase outlet 26. The liquid flowing out of the distillation tower 30 enters the second chamber 25 through the second liquid phase outlet 31. The liquid in the second chamber 25 flows back to the evaporator 10, and the gas generated by the distillation tower 30 enters the phase separation tank 40 through the third gas phase outlet 32. The phase separation tank 40 is used to condense the gas and separate the water and flow it back to the top of the distillation tower 30 to form a reusable light phase.

[0028] The specific use process of the solvent-containing wastewater treatment system provided in this embodiment is as follows: Wastewater containing a small amount of butyl acetate, penicillin metabolites and particulate matter is mixed into the inlet pipe of the evaporator 10 from the tank area. After being heated to 40-45°C, the liquid flows out from the first liquid phase outlet 12 and enters the first chamber 24 in the separation tank 20. The gas generated by evaporation in the evaporator 10 (through the first gas phase outlet 11) enters the distillation tower 30. In this process, the particulate matter and penicillin metabolites will not be vaporized and enter the distillation tower 30, and preliminary separation is achieved here. After the liquid (through the first liquid phase outlet 12) enters the first chamber 24 in the separation tank 20, the particulate matter will settle and remain in the first chamber 24. As the liquid gradually enters, the liquid gradually The liquid gradually overflows into the second chamber 25. The liquid in the second chamber 25 mixes with the liquid from the distillation tower 30 (flowing out from the second liquid phase outlet 31), returns to the evaporator 10 to vaporize the butyl acetate and water azeotrope, and then re-enters the distillation tower 30. The liquid inside the separation tank 20 is vaporized (through the second gas phase outlet 26) and enters the distillation tower 30. The distillation tower 30 performs distillation to generate gas. The gas (flowing out from the third gas phase outlet 32) is condensed and enters the phase separation tank 40. The phase separation tank 40 separates the water and gas, and re-transports the separated water to the top of the distillation tower 30. The light phase with a butyl acetate content of up to 98% in the top of the tower is sent out for reuse.

[0029] Compared with the prior art, the solvent-containing wastewater treatment system of the present application utilizes a separation tank 20 to enrich particulate matter and penicillin metabolites in a first chamber 24, and can be cleaned after a period of enrichment to prevent them from entering the distillation tower 30, thereby preventing tower plate blockage; the evaporator 10 is utilized to vaporize a large amount of solvent components in the wastewater, and effectively inhibit the decomposition and discoloration of penicillin metabolites; and the higher the vaporization rate of the evaporator 10 and the greater the flow rate, the lower the butyl acetate content in the wastewater of the distillation tower 30, but the process operating conditions and energy consumption of the evaporator 10 must be considered; the entire treatment system can operate intermittently (the evaporator 10 treats a certain amount of wastewater before proceeding to the next treatment) or continuously (the wastewater is continuously treated by the evaporator 10) to meet different production needs, and has the characteristics of not destroying heat-sensitive components, low energy consumption, and high solvent recovery rate.

[0030] It should be noted that: Evaporator 10 is a scraper falling film evaporator 10, which primarily comprises a heating chamber, a scraper assembly, and a separation chamber. The heating chamber, constructed from a jacket or tubes, provides the heat required for evaporation. A heat medium (hot water at 50°C, which is inexpensive and will not cause decomposition or discoloration of penicillin metabolites, and prevents the heavy phase in the wastewater from entering the distillation column 30) circulates within the heating chamber, heating the material within the tubes. The scraper assembly consists of a rotating shaft and scrapers, which are attached to the inner wall of the heating tubes by springs or other means. Rotating the shaft rotates the scrapers, forming a uniform liquid film on the inner wall of the tubes. The separation chamber, located below the heating chamber, separates the secondary vapor produced by evaporation from the concentrated liquid phase.

[0031] In some embodiments, the separation tank 20 may be Figure 1 The structure shown. Figure 1 The separation tank 20 includes a tank body 21, a partition 22 and a steam drum 23. The partition 22 is fixed in the tank body 21. The opposite sides of the partition 22 form a first chamber 24 and a second chamber 25. The top of the partition 22 is spaced from the inner wall of the tank body 21 so that the liquid phase in the first chamber 24 can overflow into the second chamber 25; the steam drum 23 is arranged at the top of the tank body 21, and the gas outlet of the steam drum 23 forms a second gas phase outlet 26.

[0032] The partition 22 divides the space inside the tank body 21 into a first chamber 24 and a second chamber 25. Since the top of the partition 22 is separated from the inner wall of the tank body 21, it can ensure that the liquid in the first chamber 24 can overflow into the second chamber 25, and no particulate matter will appear in the second chamber 25. Because the second chamber 25 is connected to the distillation tower 30 and needs to receive liquid from the distillation tower 30, the absence of particulate matter in the second chamber 25 means that no particulate matter will enter the distillation tower 30 due to factors such as backflow, thereby avoiding tower blockage.

[0033] Steam drum 23 comprises a main vessel and internal auxiliary devices (such as a cyclone separator, baffle separator, or porous plate). The main vessel is fixed to the top of tank body 21 and can be positioned directly above second chamber 25. Since second chamber 25 is entirely liquid, steam drum 23 vaporizes the liquid to form gas during operation. However, since first chamber 24 and second chamber 25 are connected, any liquid in first chamber 24 will also vaporize. The provision of steam drum 23 ensures stable collection of the gas phase, preventing the gas phase from carrying liquid impurities into distillation column 30, thereby improving the separation efficiency of distillation column 30. It also simplifies the structure of separation tank 20 and reduces equipment complexity.

[0034] In some embodiments, an improved embodiment of the separation tank 20 can be as follows Figure 1 The structure shown. Figure 1The bottom of the tank body 21 is provided with a first external discharge pipe 27 in communication with the first chamber 24. The first external discharge pipe 27 can be provided at the bottom of the first chamber 24. Since sediment is regularly accumulated in the first chamber 24, when the sediment exceeds the height of the partition 22, it will enter the second chamber 25, causing the risk of blockage of the distillation tower 30. Therefore, the first external discharge pipe 27 is provided to regularly discharge the sediment in the first chamber 24, thereby ensuring the long-term stable operation of the separation tank 20. Compared with directly disassembling the separation tank 20 to clean the first chamber 24, the technical solution of this embodiment can reduce the frequency of equipment maintenance and production interruption time.

[0035] In order to facilitate the discharge of sediment, a valve can be set on the first external discharge pipe 27. The size of the first external discharge pipe 27 can be larger to facilitate the discharge of sediment. When cleaning is required, the valve can be opened to operate.

[0036] In some embodiments, an improved embodiment of the above-mentioned solvent-containing wastewater treatment system can be adopted as follows Figure 1 The structure shown. Figure 1 A condenser 50 is further provided between the third gas phase outlet 32 ​​and the phase separation tank 40 .

[0037] It should be explained that the distillation tower 30 includes a tower body, a pedal + downcomer + overflow weir located inside the tower body, a reboiler located at the bottom of the tower, and a condenser 50 located at the top of the tower. The distillation tower 30 utilizes the different volatilities of the components in the mixture (volatile components: low boiling point, easier to vaporize; non-volatile components: high boiling point, more difficult to vaporize) to gradually achieve component separation through "reverse flow + multiple mass transfer" of the gas-liquid two phases in the tower.

[0038] Directly discharging the gas from the top of the distillation tower 30 will cause energy waste. By setting a third gas phase outlet 32, the gas there is condensed (condensed to 30°C) and then enters the phase separation tank 40, which can enable the phase separation tank 40 to separate the gas therein, separate the gas and water, and discharge the water back to the top of the tower.

[0039] The technical solution of this embodiment condenses the gas flowing out of the distillation tower 30 into liquid, avoiding incomplete separation caused by the coexistence of gas and liquid in the phase separation tank 40, and improving the phase separation efficiency; the temperature of the material after condensation is reduced, which reduces the gas phase loss in the phase separation tank 40, improves the solvent recovery efficiency, and reduces the load of the phase separation tank 40.

[0040] It should be noted that the phase separation tank 40 includes a shell, a feeding device, an enhanced separation structure (corrugated plates, filler stacking, etc.), and a discharging device. It uses the density difference of immiscible fluids to achieve the sedimentation or buoyancy of the dispersed phase (small phase) to the continuous phase (large phase) under the action of gravity, and finally forms a clear stratified interface, and then completes the separation through precise discharge.

[0041] The structure of the phase separation tank 40 is similar to that of the separation tank 20. It has two chambers inside (hereinafter referred to as chamber a and chamber b). The gas from the distillation tower 30 enters chamber a after condensation. Chamber a has an enhanced separation structure. The liquid is settled and separated in chamber a to obtain water. The excess water will overflow into chamber b. A pipe is provided at the bottom of chamber a, which allows the water at the bottom of chamber a to flow back to the top of the distillation tower 30, thereby obtaining a light phase with a butyl acetate content of up to 98%. The main components of chamber b are water overflowing from chamber a and gas located on top of the water. The top of chamber b is provided with an outlet connected to a vacuum pump 60. The vacuum pump 60 is used to maintain the entire system in a vacuum state. An external discharge pipe can also be provided at the bottom of chamber b to regularly discharge the water in chamber b to prevent deterioration caused by long-term storage. The discharge of water in chamber b can also ensure the balance of inflow and outflow in the phase separation tank 40 and maintain the vacuum environment.

[0042] Specifically, considering the requirements and feasibility of the phase separation tank 40 during operation, a pressure gauge, a safety valve, a temperature sensor, etc. may be provided on the phase separation tank 40 .

[0043] As an alternative embodiment, without setting up the condenser 50, a refrigerant such as ice cubes can be set on the periphery of the gas phase pipeline connecting the distillation tower 30 and the phase separation tank 40 to achieve preliminary condensation of the gas phase in the pipe during the flow. This structure has low cost and is easy to arrange.

[0044] In some embodiments, an improved embodiment of the phase separation tank 40 can be as follows: Figure 1 The structure shown. Figure 1 The phase separation tank 40 has a fourth gas phase outlet 41, and the solvent-containing wastewater treatment system further includes a vacuum pump 60 connected to the fourth gas phase outlet 41. The vacuum pump 60 achieves a vacuum throughout the entire system, ensuring a vacuum level of 20 kPa. Under vacuum conditions, the azeotropic temperature of butyl acetate and water drops from over 90°C at atmospheric pressure to 40-45°C, further reducing the heating temperature of the evaporator 10 and preventing decomposition of heat-sensitive substances. The low boiling point makes the solvent more easily vaporized, increasing the gas phase output of the evaporator 10 and improving the processing capacity of the distillation column 30. It also reduces the accumulation of non-condensable gases within the system, preventing a decrease in heat transfer efficiency.

[0045] In some embodiments, an improved embodiment of the distillation tower 30 can be as follows Figure 1 The structure shown. Figure 1A second external discharge pipe 33 is provided at the bottom of the distillation tower 30. Since the entire system is in a vacuum state, the inflow and outflow of the distillation tower 30 must be balanced to maintain a vacuum environment. After distillation and separation, the low-solvent content wastewater (butyl acetate ≤ 100 ppm) remaining at the bottom of the tower is discharged from the system through the second external discharge pipe 33. This not only allows for the timely discharge of purified wastewater, preventing accumulation at the bottom of the tower that could cause abnormal liquid levels in the distillation tower 30, thus ensuring stable distillation operation, but also maintains the system's vacuum environment.

[0046] It should be noted that the butyl acetate content in the wastewater is as low as 100 ppm, meeting environmental emission standards while also avoiding solvent waste at the bottom of the tower, achieving both environmental and economic benefits. A discharge pump and valve can be provided on the second discharge pipe 33. When discharge is required, the valve and discharge pump are opened, and the discharge pump extracts the wastewater from the bottom of the distillation tower 30 for discharge.

[0047] Specifically, a liquid transmitter 34 is provided on the outside of the distillation tower 30, with both the liquid inlet and liquid outlet sides of the liquid transmitter 34 in communication with the distillation tower 30. The liquid transmitter 34 detects the pressure difference or liquid level of the liquid phase within the tower, providing real-time feedback on changes in the liquid volume / liquid level within the distillation tower 30. This signal is transmitted to the control system, enabling real-time monitoring of the liquid level within the distillation tower 30 and ensuring continuous and stable operation of the system. Furthermore, based on the detection value of the liquid level transmitter, the inlet and outlet volumes of the upstream and downstream streams of the distillation tower 30 can be adjusted to avoid a decrease in solvent recovery due to abnormal liquid levels.

[0048] The liquid inlet and outlet sides of the liquid transmitter 34 are both provided with switch valves, and the working state of the liquid transmitter 34 (eg, open or close) can be switched by adjusting the switch valves.

[0049] The distillation tower 30 is also equipped with a temperature transmitter 35 and a pressure transmitter 36. The temperature transmitter 35 monitors the temperature of different trays within the distillation tower 30 (e.g., the top, the middle, and the bottom) in real time, reflecting the progress of solvent-water separation. The pressure transmitter 36 monitors the pressure within the distillation tower 30 in real time and cooperates with the vacuum pump 60 to maintain a stable vacuum level in the system. Both signals are transmitted to the control system for adjusting parameters such as heating capacity, vacuum pump 60 pumping speed, and reflux ratio. This structure combines parameter visualization with precise control, preventing product substandardness or equipment failure caused by temperature or pressure anomalies. Real-time parameter adjustment reduces energy consumption while ensuring solvent recovery and light phase purity, achieving a balanced balance between technical performance and economic efficiency.

[0050] In order to conveniently receive the detection values ​​and working conditions of the liquid transmitter 34, the temperature transmitter 35 and the pressure transmitter 36, a PLC system can be set up, and the liquid transmitter 34, the temperature transmitter 35 and the pressure transmitter 36 can be connected to the PLC system through wire connection or communication connection. Then, when the distillation tower 30 is working, the detection values ​​and working conditions (such as whether they are turned on) of the liquid transmitter 34, the temperature transmitter 35 and the pressure transmitter 36 can be observed through the PLC system. The liquid transmitter 34, the temperature transmitter 35 and the pressure transmitter 36 can also be controlled through the PLC system. For example, a standard value can be set. When the value detected by a certain transmitter exceeds the standard value, the PLC system will issue an alarm (through an audible and visual alarm) to remind the operator to check in time to ensure the safety and accuracy of the entire processing process.

[0051] In some embodiments, an improved embodiment of the above-mentioned solvent-containing wastewater treatment system can be adopted as follows Figure 1 The structure shown. Figure 1 A power pump 70 is installed between the second chamber 25 and the evaporator 10, and between the phase-separation tank 40 and the distillation tower 30. The liquid in the second chamber 25 is pressurized by the power pump 70, overcoming the resistance of the pipeline and flowing back to the evaporator 10, ensuring smooth liquid phase circulation. The water phase in the phase-separation tank 40 is also pressurized by the power pump 70 and stably delivered to the top of the distillation tower 30, maintaining the reflux flow required for distillation.

[0052] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A system for treating solvent-containing wastewater, characterized in that: include: an evaporator having a first gas phase outlet and a first liquid phase outlet; a separation tank having a first chamber, a second chamber, and a second gas phase outlet, wherein the first chamber is connected to the first liquid phase outlet, and the liquid in the second chamber is used to flow back to the evaporator; a distillation tower having a second liquid phase outlet and a third gas phase outlet, the distillation tower being in communication with the first gas phase outlet and the second gas phase outlet, and the second liquid phase outlet being in communication with the second chamber; a phase separation tank, connected to the third gas phase outlet, for separating the water phase and flowing the water phase back to the top of the distillation tower; Among them, wastewater enters the evaporator, the gas flowing out of the first gas phase outlet in the evaporator enters the distillation tower, the liquid flowing out of the first liquid phase outlet enters the first chamber, the liquid in the separation tank evaporates and enters the distillation tower through the second gas phase outlet, the liquid flowing out of the distillation tower enters the second chamber through the second liquid phase outlet, the liquid in the second chamber flows back to the evaporator, the gas generated by the distillation tower enters the phase separation tank through the third gas phase outlet, the phase separation tank is used to condense the gas and separate the water and flow it back to the top of the distillation tower to form a reusable light phase.

2. The solvent-containing wastewater treatment system according to claim 1, characterized in that: The separation tank comprises: Tank; a partition fixedly disposed in the tank body, wherein opposite sides of the partition form the first chamber and the second chamber, and a top of the partition is spaced from an inner wall of the tank body so that the liquid in the first chamber can overflow into the second chamber; A steam drum is provided at the top of the tank body, and a gas outlet of the steam drum forms the second gas phase outlet.

3. The solvent-containing wastewater treatment system according to claim 2, characterized in that: The bottom of the tank body is provided with a first external discharge pipe communicating with the first chamber.

4. The solvent-containing wastewater treatment system according to claim 1, wherein: The evaporator is a scraped falling film evaporator.

5. The solvent-containing wastewater treatment system according to claim 1, wherein: A condenser is further provided between the third gas phase outlet and the phase separation tank.

6. The solvent-containing wastewater treatment system according to claim 1, wherein: The phase separation tank has a fourth gas phase outlet, and the solvent-containing wastewater treatment system also includes a vacuum pump connected to the fourth gas phase outlet.

7. The solvent-containing wastewater treatment system according to claim 1, wherein: A second external pipe is provided at the bottom of the distillation tower.

8. The solvent-containing wastewater treatment system according to claim 7, characterized in that: A liquid transmitter is provided on the outside of the distillation tower, and both the liquid inlet side and the liquid outlet side of the liquid transmitter are in communication with the distillation tower.

9. The system for treating solvent-containing wastewater according to claim 1, wherein: A power pump is provided between the second chamber and the evaporator, and between the phase separation tank and the distillation tower.

10. The solvent-containing wastewater treatment system according to claim 1, wherein: The distillation tower is also provided with a temperature transmitter and a pressure transmitter.

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