A DMF water removal device

Abstract

This utility model discloses a DMF dehydration device, including a dehydration reactor and a distillation column. The dehydration reactor is equipped with a DMF inlet pipe, a toluene inlet pipe, and a DMF collection pipe. The dehydration reactor is also equipped with a stirring device and a vacuum device. A distillation vapor inlet pipe connects the dehydration reactor and the distillation column. The distillation column is equipped with a distillation liquid reflux pipe, which is connected to a condenser. The condenser's condensate outlet pipe is connected to a toluene separator. The toluene separator is equipped with a toluene outlet pipe and a wastewater outlet pipe. The toluene outlet pipe is connected to a toluene circulation pump, which is equipped with a toluene circulation pipe connected to the toluene inlet pipe. This invention solves the problems of high energy consumption, large equipment investment, high technical requirements for operation, and the decomposition of DMF under prolonged high-temperature conditions in existing dehydration devices.

Description

Technical Field

[0001] This utility model relates to the field of wastewater treatment, specifically to a DMF dewatering device. Background Technology

[0002] In drug synthesis, dimethylformamide (DMF) is frequently used as a solvent and catalyst in key reactions such as amination, acylation, and formylation due to its excellent properties. After the reaction, subsequent steps such as quenching, extraction, crystallization, filtration, and washing generate large amounts of DMF-containing wastewater, which not only wastes solvent resources but also puts significant pressure on environmental remediation. Therefore, achieving efficient recovery and recycling of DMF has significant economic and environmental benefits.

[0003] However, the azeotropic system formed by DMF and water severely limits its recovery efficiency. Although conventional simple distillation can remove most of the water, it cannot obtain high-purity DMF. When the water content of DMF in wastewater drops to about 5%, the difficulty and cost of further purification increase dramatically.

[0004] Currently, commonly used deep dehydration methods in industry mainly include distillation, molecular sieve adsorption, and salting-out. However, these methods all have significant limitations: high-purity distillation suffers from extremely high energy consumption, large equipment investment, and high technical requirements for operation. Furthermore, DMF carries the risk of thermal decomposition in high-temperature systems over extended periods, necessitating strict control of temperature and time. Molecular sieves have disadvantages such as high pretreatment requirements, limited adsorption capacity, frequent replacement or regeneration, unsuitability for materials with extremely high moisture content, and the potential for wear and pulverization. Salting-out methods suffer from incomplete dehydration, limited efficiency, introduction of new pollution from salts or metal ions, generation of saline wastewater, environmental pollution, and equipment corrosion.

[0005] Therefore, there is an urgent need to develop a DMF dewatering device that can efficiently remove water, generate no new polluting wastewater, and recycle solvent resources. Utility Model Content

[0006] The purpose of this invention is to provide a new DMF dewatering device, which aims to improve the problems of high energy consumption, large equipment investment, high technical requirements for operation, and the decomposition of DMF in a high-temperature system for a long time in existing dewatering devices.

[0007] This utility model is implemented as follows: A DMF dehydration device includes a dehydration reaction vessel and a distillation column. The dehydration reaction vessel is equipped with a water-containing DMF input pipe, a toluene input pipe and a DMF collection pipe. The dehydration reaction vessel is also equipped with a stirring device and a vacuum device. A distillation vapor inlet pipe is connected between the dehydration reactor and the distillation column. The distillation column is equipped with a distillation liquid reflux pipe, which is connected to a condenser. The condenser's condensate outlet pipe is connected to a toluene separator. The toluene separator is equipped with a toluene outlet pipe and a wastewater outlet pipe. The toluene outlet pipe is connected to a toluene circulation pump, which is equipped with a toluene circulation pipe. The toluene circulation pipe is connected to the toluene inlet pipe.

[0008] As one embodiment of this utility model, the above-mentioned stirring device includes a stirring motor, a speed reducer, a stirring rod, and a paddle blade.

[0009] As one embodiment of this utility model, the evaporation temperature of the above-mentioned dehydration reactor is 80-90℃.

[0010] As one embodiment of this utility model, the distillation column is provided with a packing layer, the height of which is 3-4m.

[0011] As one embodiment of this utility model, a distillation reflux pipe is also provided between the dehydration reactor and the distillation column to allow the DMF-containing water in the distillation column to flow back into the dehydration reactor.

[0012] As one embodiment of this utility model, the above-mentioned vacuum device includes a nitrogen filling pipe and a vacuum extraction pipe.

[0013] As one embodiment of this utility model, the vacuum degree inside the vacuum extraction tube is 10-20 kPa.

[0014] As one embodiment of this utility model, the above-mentioned wastewater output pipe is connected to a wastewater collection tank.

[0015] In one embodiment of this utility model, a vacuum tube is also connected to the condenser, and a vacuum connection tube is provided on the toluene separator, which is connected to the vacuum tube.

[0016] The beneficial effects of this utility model are: 1. This utility model adopts low-temperature evaporation and low-vacuum operation conditions, which significantly reduces energy consumption, avoids DMF decomposition at high temperatures, improves process safety and stability, and has low overall equipment investment and operating costs. It has good economic efficiency and practicality, realizes efficient recovery and reuse of solvent resources, avoids DMF incineration, and has both economic and environmental benefits. 2. The overall operation process of this utility model is simple, the water removal efficiency is high, and it can stably obtain high-purity DMF with a moisture content of less than 0.1%. The toluene in the process can be recycled, and no wastewater containing salt or metal ions is generated, which meets the requirements of green chemical industry. Attached Figure Description

[0017] The accompanying drawings, which form part of this utility model, are used to provide a further understanding of the utility model, making other features, objects, and characteristics of the utility model more apparent. The illustrative embodiments of the utility model and their descriptions are used to explain the utility model and do not constitute an undue limitation of the utility model.

[0018] Figure 1 This is a schematic diagram of the overall structure and principle of this utility model; Figure 2 This is a schematic diagram of the structure of the dehydration reactor of this utility model; Figure 3 This is a schematic diagram of the structure of the distillation column of this utility model; In the diagram: 1. Dehydration reactor; 11. DMF inlet pipe; 12. Toluene inlet pipe; 13. DMF collection pipe; 2. Distillation column; 21. Distillation vapor inlet pipe; 23. Distillation liquid reflux pipe; 24. Packing layer; 3. Condenser; 31. Condensation outlet pipe; 4. Vacuum pipe; 5. Toluene separator; 51. Toluene outlet pipe; 52. Wastewater outlet pipe; 53. Vacuum connection pipe; 6. Toluene circulation pump; 61. Toluene circulation pipe; 7. Wastewater collection tank; 8. Stirring device; 81. Stirring motor; 82. Stirring rod; 83. Paddle blade; 22. Distillation reflux pipe; 9. Vacuum device; 91. Nitrogen charging pipe; 92. Vacuum extraction pipe. Detailed Implementation

[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0020] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0021] Since the main function of the sealing ring is to seal, it is necessary to ensure that no flash is generated during the production process. Increasing the mold closing pressure in the horizontal direction can solve the problem of flash overflow in the horizontal direction. However, in the vertical direction, it is necessary to avoid excess molten casting material from being discharged in the vertical direction.

[0022] In this example, N,N-dimethylformamide is a toxic substance. When humans or animals continuously inhale large amounts of dimethylformamide, it will cause weight loss and hinder hematopoietic function. Therefore, the DMF dewatering device of this invention is mainly used to remove DMF from wastewater containing DMF through dehydration reaction, distillation separation and toluene recycling, and then recycle and collect it so that the wastewater after DMF removal meets the standards for safe discharge.

[0023] Working principle: Utilizing the azeotropic property of toluene and water, toluene is added to aqueous DMF. The vacuum degree in the dehydration reactor is then adjusted to 10-20 kPa, and the internal temperature of the dehydration reactor is controlled at 80-90℃. Toluene and water are distilled under reduced pressure until no more is collected. The contents of the dehydration reactor are DMF with a water content of less than 0.1%. A 3.5m packed column is installed in distillation column 2 to prevent DMF from being distilled out. After the toluene and water in the toluene receiving tank are separated, the toluene can be recycled.

[0024] like Figures 1-3 As shown, this utility model discloses a DMF dehydration device, including a dehydration reactor 1 and a distillation column 2. The dehydration reactor 1 is equipped with a water-containing DMF input pipe 11, a toluene input pipe 12, and a waste liquid discharge pipe 13. The dehydration reactor 1 is also equipped with a stirring device 8 and a vacuum device 9. A distillation gas phase input pipe 21 is connected between the dehydration reactor 1 and the distillation column 2. A distillation liquid phase reflux pipe 23 is provided on the distillation column 2. The distillation liquid phase reflux pipe 23 is connected to a condenser 3. The condensation output pipe 31 of the condenser 3 is connected to a toluene separation tank 5. The toluene separation tank 5 is equipped with a toluene output pipe 51 and a wastewater output pipe 52. The toluene output pipe 51 is connected to a toluene circulation pump 6. The toluene circulation pump 6 is equipped with a toluene circulation pipe 61, which is connected to the toluene input pipe 12.

[0025] Specifically, such as Figures 1-2 As shown, the dehydration reactor 1 is the main reaction component of this device. It is equipped with a DMF inlet pipe 11 containing aqueous solution, a toluene inlet pipe 12, and a wastewater outlet pipe 13. During operation, aqueous DMF wastewater enters the dehydration reactor through the DMF inlet pipe 11. Simultaneously, toluene also enters the dehydration reactor 1 through the toluene inlet pipe 12. Toluene acts as an azeotropic agent here, forming an azeotrope with water, thus more effectively separating water from the DMF. After the reaction is complete, the toluene and water are distilled under reduced pressure until no more water is collected. The contents of the dehydration reactor are DMF with a water content of less than 0.1%, which is then discharged through the DMF collection pipe 13. The DMF is collected through the DMF collection pipe 13, achieving DMF recovery and ensuring that the wastewater after DMF removal meets safe discharge standards.

[0026] To improve the reaction rate, a stirring device 8 is also installed on the dehydration reactor 1. The stirring device consists of a stirring motor, a reducer, a stirring rod, and a paddle blade. The stirring motor drives the stirring rod to rotate, which in turn drives the paddle blade to rotate inside the reactor. This paddle blade design effectively stirs the materials inside the reactor, ensuring thorough mixing of toluene and DMF wastewater and improving the efficiency of azeotropic dehydration. The speed of the stirring motor can be adjusted according to the actual reaction conditions, generally between 50 and 200 r / min.

[0027] In order to lower the boiling point of water, thereby reducing the reaction temperature, preventing DMF from decomposing at high temperatures, and improving process safety and stability, a vacuum device 9 is installed on the dehydration reactor 1.

[0028] The vacuum device 9 includes a nitrogen charging pipe 91 and a vacuum extraction pipe 92. During the reaction, the internal gas is first replaced by the nitrogen charging pipe 91, and then the nitrogen in the reactor is extracted by the vacuum extraction pipe 92, creating a certain vacuum level inside the reactor, controlled at 10-20 kPa. A lower vacuum level helps to lower the boiling point of water. The evaporation temperature of the dehydration reactor is controlled at 80-90℃. Within this temperature range, the azeotropic reaction proceeds smoothly while avoiding excessive decomposition of DMF.

[0029] like Figure 1 and Figure 3 As shown, to prevent DMF from being carried out by distillation during the reduced-pressure evaporation process, a distillation column 2 is also installed on the dehydration reactor 1. The distillation column 2 is connected to the dehydration reactor 1 via a distillation vapor inlet pipe 21. The vapor containing DMF, toluene, and water evaporated at low temperature from the dehydration reactor enters the distillation column 1 through the distillation vapor inlet pipe 21. A packing layer 24 with a height of 3.5m is installed inside the distillation column 2. The function of the packing layer is to isolate DMF and prevent it from entering the subsequent condenser 3 during distillation.

[0030] In distillation column 2, due to the different boiling points of each component, the vapors of DMF, toluene and water will undergo multiple gas-liquid exchanges in the packing layer 24 to achieve preliminary separation. Distillation column 2 is equipped with a distillation liquid reflux pipe 23, and the vapor after distillation separation enters the condenser 3 through the distillation liquid reflux pipe 23.

[0031] Meanwhile, a distillation reflux pipe 22 is also installed between the dehydration reactor 1 and the distillation column 2. During the distillation process, the water containing DMF at the bottom will flow back from the distillation column 2 to the dehydration reactor 1 for another azeotropic dehydration reaction.

[0032] like Figure 1As shown, the condenser 3 of this invention is connected to the distillation column 2 via a liquid reflux pipe 23. The vapor exiting the distillation column 2 enters the condenser 3 and exchanges heat with the cooling medium inside the condenser 3, thus liquefying the vapor. The vapor consists of toluene and water. To recover the toluene, a toluene separator 4 is connected to the condenser output pipe 31 of the condenser 3. The liquefied mixture enters the toluene separator 5 through the condenser output pipe 31.

[0033] The condenser 3 is also connected to a vacuum tube 4, which is connected to a vacuum connection tube 53 on the toluene separator 5. The vacuum system can maintain a negative pressure state in the condenser and the toluene separator, which is beneficial for the condensation of vapor and the flow of liquid.

[0034] The toluene separator 5 receives the mixed liquid from the condenser 3. Within the toluene separator 5, stratification occurs due to the density difference between toluene and water. The toluene separator 5 is equipped with a toluene outlet pipe 51 and a wastewater outlet pipe 52. The upper layer of toluene is connected to a toluene circulation pump 6 via the toluene outlet pipe 51. The toluene circulation pump 6 then re-feeds the toluene through the toluene circulation pipe 61 back to the toluene inlet pipe 12 of the dehydration reactor 1, achieving the recycling of toluene, improving toluene utilization, and reducing production costs.

[0035] The toluene waste liquid in the lower layer of the toluene separator 5 contains a small amount of water and impurities. It is connected to the wastewater collection tank 7 through the wastewater output pipe 52 and then undergoes unified wastewater treatment until it meets the discharge standards.

[0036] The device operation process is as follows: First, in the dehydration reactor 1, the air inside is replaced with nitrogen three times through the nitrogen filling pipe 91. Then, 8000L of waste liquid containing water DMF is pumped into the dehydration reactor through the water DMF input pipe 11. Then, 1300L of toluene is pumped into the dehydration reactor through the toluene input pipe 12. The stirring device 8 is used to stir and mix thoroughly. Secondly, the interior is vacuumed. The vacuum level is controlled at 10~20 kPa through the vacuum pump pipe 92. After the pressure stabilizes, the dehydration reactor 1 is heated and the temperature is controlled at 80~90℃. The vapor in the dehydration reactor 1 enters the distillation column 2 and is separated into components through the 3.5-meter packed column 24. The azeotropic substances of toluene and water are condensed by the condenser 3 and collected in the toluene separation tank 5, while DMF is returned to the dehydration reactor 1 through the distillation reflux pipe 22. Once almost no distillate is collected, the dehydration reactor 1 is cooled, and nitrogen is introduced through the nitrogen purging pipe 91. The DMF in the dehydration reactor 1 can then be recovered and transferred through the DMF collection pipe 13. The distillate in the toluene separator 5 is allowed to settle completely before being separated into layers. The lower layer of wastewater is placed in the wastewater collection tank 7, while the upper layer of toluene is pumped back into the toluene input pipe 12 through the toluene circulation pump 6 and the toluene circulation pipe 61, ready for use in the next batch of water-containing DMF for dehydration.

[0037] Furthermore, the technical solutions of the various embodiments of this utility model can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0038] The above-described embodiments are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of this utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the appended claims.

Claims

1. A DMF dewatering device, characterized in that, It includes a dehydration reactor (1) and a distillation column (2). The dehydration reactor (1) is equipped with a water-containing DMF inlet pipe (11), a toluene inlet pipe (12) and a DMF collection pipe (13). The dehydration reactor (1) is also equipped with a stirring device (8) and a vacuum device (9). A distillation vapor inlet pipe (21) is connected between the dehydration reactor (1) and the distillation column (2). A distillation liquid reflux pipe (23) is provided on the distillation column (2). A condenser (3) is connected to the distillation liquid reflux pipe (23). A toluene separator (5) is connected to the condenser outlet pipe (31). A toluene outlet pipe (51) and a wastewater outlet pipe (52) are provided on the toluene separator (5). A toluene circulation pump (6) is connected to the toluene circulation pump (6). A toluene circulation pipe (61) is provided on the toluene circulation pump (6). The toluene circulation pipe (61) is connected to the toluene inlet pipe (12).

2. The DMF dewatering device according to claim 1, characterized in that, The stirring device (8) includes a stirring motor (81), a speed reducer, a stirring rod (82), and a paddle blade (83).

3. The DMF dewatering device according to claim 2, characterized in that, The evaporation temperature of the dehydration reactor (1) is 80-90℃.

4. The DMF dewatering device according to claim 3, characterized in that, The distillation column (2) is provided with a packing layer (24) with a height of 3-4m.

5. The DMF dewatering device according to claim 4, characterized in that, A distillation reflux pipe (22) is also provided between the dehydration reactor (1) and the distillation column (2), through which the DMF-containing water in the distillation column (2) is refluxed back into the dehydration reactor (1).

6. The DMF dewatering device according to claim 5, characterized in that... The vacuum device (9) includes a nitrogen filling pipe (91) and a vacuum extraction pipe (92).

7. The DMF dewatering device according to claim 6, characterized in that, The vacuum level inside the vacuum extraction pipe (92) is 10-20 kPa.

8. The DMF dewatering device according to claim 1, characterized in that, The wastewater output pipe (52) is connected to a wastewater collection tank (7).

9. The DMF dewatering device according to claim 1, characterized in that, The condenser (3) is also connected to a vacuum tube (4), and the toluene separator (5) is provided with a vacuum connection tube (53), which is connected to the vacuum tube (4).

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