A solvent recovery method and system for high-solvent wastewater in pharmaceutical and chemical industries

Abstract

The invention discloses a solvent recovery method and system for high-solvent wastewater in pharmaceutical and chemical industries, wherein a security filter and an ultrafiltration device are used to finely filter the high-solvent wastewater to obtain a filtered solution; the filtered solution is treated again by a security filter and an AMS nanofiltration device to obtain a recovered solvent. The recovery system comprises a raw water tank, which is sequentially connected to a raw water booster pump, a first security filter and an ultrafiltration device via a pipeline, the water outlet of the ultrafiltration device is connected to a transfer water tank via a pipeline, and the return water outlet of the ultrafiltration device is connected to the raw water tank via a pipeline; the transfer water tank is sequentially connected to a concentrated liquid booster pump, a second security filter, a high-pressure pump and an AMS nanofiltration device via a pipeline, the water outlet of the AMS nanofiltration device is connected to a terminal water tank via a pipeline, and the return water outlet of the AMS nanofiltration device is connected to the transfer water tank via a pipeline. The invention has the characteristics of being easy to operate, being able to effectively improve the solvent purification effect and the water recycling rate.

Description

Technical Field

[0001] The invention relates to a recovery and treatment system for pharmaceutical and chemical high-solvent wastewater, in particular to a solvent recovery method and system for pharmaceutical and chemical high-solvent wastewater. Background Art

[0002] Most of the production processes in the pharmaceutical chemical industry involve multiple links such as synthesis, extraction, and distillation. A large amount of organic matter such as solvents, additives, and catalysts are introduced into the production process. When the chemical reaction is incomplete or solvent media are used in the production process, the wastewater will contain various organic acids, alcohols, aldehydes, ketones, ethers, and epoxides, and the pollutant content is very high. This leads to complex pollutant composition of production wastewater, high content of toxic and harmful substances, high salt content in some wastewater, and high content of ammonia nitrogen and organic nitrogen, which brings great difficulty to the treatment of wastewater. Halogenated hydrocarbons such as dichloromethane are the main solvents in the pharmaceutical industry. In order to reduce consumption, pollution, and recycle resources, it is necessary to treat the wastewater generated by dichloromethane and other solvents. For the recycling of solvent wastewater such as dichloromethane, the existing solvent recycling mainly adopts dehydration method to reduce the water content in the solvent and remove other organic components; the dehydration method mainly adopts dehydration with a dehydrating agent, and commonly used dehydrating agents include alkaline dehydrating agents, acidic dehydrating agents and neutral dehydrating agents, such as alkaline dehydrating agents such as calcium hydride and acidic dehydrating agents, neutral dehydrating agents such as molecular sieves; they can reduce the water content in the solvent to about 0.5%; but the operation is relatively troublesome, not only other organic components are difficult to remove, but also involves the problem of recycling and application, the water content and other organic components of the recovered solvent are still relatively high, and the recycling effect is not ideal. Moreover, in this process, the discharge of wastewater is also large, and the utilization rate of water circulation is also low. Therefore, the existing technology has the problems of cumbersome operation, unsatisfactory purification effect and low water circulation utilization rate. Summary of the invention

[0003] The purpose of the present invention is to provide a solvent recovery method and system for pharmaceutical chemical high-solvent wastewater. The present invention is easy to operate, can effectively improve the solvent purification effect and increase the water recycling rate.

[0004] The technical solution of the present invention is a solvent recovery method for high-solvent wastewater in pharmaceutical and chemical industries, which uses a security filter and an ultrafiltration device to finely filter the high-solvent wastewater to obtain a filtered solution; and uses a security filter and an AMS nanofiltration device to re-treat the filtered solution to obtain a recovered solvent.

[0005] In the aforementioned solvent recovery method for high-solvent wastewater in pharmaceutical and chemical industries, during the use of the AMS nanofiltration device, the service life of the AMS nanofiltration membrane is increased by gradually increasing the wastewater temperature according to the rate of decrease of the liquid outlet velocity; every time the liquid outlet velocity decreases by 5%, the wastewater temperature increases by 5°C until the wastewater temperature reaches the set threshold.

[0006] A solvent recovery system for pharmaceutical and chemical high-solvent wastewater comprises a raw water tank, which is sequentially connected to a raw water booster pump, a first safety filter and an ultrafiltration device via a pipeline, a water outlet of the ultrafiltration device is connected to a transfer water tank via a pipeline, and a water return port of the ultrafiltration device is connected to the raw water tank via a pipeline; the transfer water tank is sequentially connected to a concentrate booster pump, a second safety filter, a high-pressure pump and an AMS nanofiltration device via a pipeline, a water outlet of the AMS nanofiltration device is connected to a terminal water tank via a pipeline, and a water return port of the AMS nanofiltration device is connected to the transfer water tank via a pipeline.

[0007] In the aforementioned solvent recovery system for pharmaceutical and chemical high-solvent wastewater, the transfer water tank is a cylindrical tank body; the inner wall of the transfer water tank is provided with a spirally distributed first heat conducting plate.

[0008] In the aforementioned solvent recovery system for high-solvent wastewater in pharmaceutical and chemical industries, a temperature regulating jacket is provided outside the transfer water tank, and a heating water tank is provided at the bottom of the temperature regulating jacket; a hot water inlet is provided at the lower end of the temperature regulating jacket, and the hot water inlet is connected to the water outlet of the heating water tank through a hot water pipe; a cold water outlet is provided at the upper end of the temperature regulating jacket, and the cold water outlet is connected to the water inlet of the heating water tank through a cold water pipe.

[0009] In the aforementioned solvent recovery system for pharmaceutical and chemical high-solvent wastewater, a water delivery pump is provided on the hot water pipe.

[0010] In the aforementioned solvent recovery system for pharmaceutical and chemical high-solvent wastewater, a group of evenly distributed middle-layer heating tubes are provided in the middle layer of the heating water tank, and upper-layer heating tubes and lower-layer heating tubes distributed vertically are provided between adjacent middle-layer heating tubes.

[0011] In the aforementioned solvent recovery system for pharmaceutical and chemical high-solvent wastewater, the lower heating tube and the upper heating tube are both arranged inclined, with an inclination angle of 40-50 degrees.

[0012] In the aforementioned solvent recovery system for high-solvent wastewater in pharmaceutical and chemical industries, the transfer water tank is fixed to the ground via a support; a lifting mechanism is provided at the bottom of the heating water tank; the lifting mechanism includes a plurality of guide rods symmetrically arranged on the side wall of the heating water tank, a lifting cylinder is provided at the bottom of the heating water tank, and a water tank fixing seat is provided at the output end of the lifting cylinder; a group of evenly arranged second heat conducting plates are provided on the bottom surface of the temperature regulating jacket, and a heating groove corresponding to the position of the second heat conducting plates is provided on the upper end surface of the heating water tank; the cross-section of the second heat conducting plate is a trapezoidal structure; and air guide grooves are provided between adjacent second heat conducting plates.

[0013] In the aforementioned solvent recovery system for pharmaceutical and chemical high-solvent wastewater, both the hot water pipe and the cold water pipe are provided with metal telescopic pipes.

[0014] Compared with the prior art, the present invention uses an ultrafiltration device and an AMS nanofiltration device to perform double filtration on wastewater containing solvents, extracts residual solvents from mother liquor wastewater, and recycles and reuses to create economic benefits, thereby replacing the traditional method of recovering solvents by dehydration method, which is not only simple in process and convenient in operation, but also has a good purification effect; at the same time, the present invention uses an ultrafiltration device to perform preliminary filtration on wastewater, and uses an AMS nanofiltration device to perform secondary filtration on wastewater, and the two are effectively combined, which can reduce the amount of wastewater during separation and filtration, and facilitate the application of in-situ water, thereby improving the utilization rate of water circulation in the pharmaceutical chemical industry and reducing the discharge of wastewater; after physical separation by nanofiltration membrane, the concentration of pollutants in the wastewater is significantly reduced, which can be applied in situ or directly go to the wastewater treatment station, and the residual solvent in the concentrate can be re-extracted. The present invention uses the nanofiltration membrane in the AMS nanofiltration device for phase-free separation, and the drug components can be concentrated and reused without being destroyed, which can reduce the amount of mother liquor wastewater generated, reduce the concentration of pollutants in the mother liquor wastewater, and reduce the pressure of subsequent sewage treatment, thereby effectively improving the water circulation utilization rate. In summary, the present invention has the characteristics of being easy to operate, being able to effectively improve the solvent purification effect and increasing the water recycling rate.

[0015] In addition, the present invention utilizes the characteristic that the pore size of the nanofiltration membrane will become larger when heated, and sets a temperature regulating jacket outside the transfer water tank to adjust the temperature of the waste liquid in the transfer water tank, thereby adjusting the pore size of the nanofiltration membrane. When the pore size of the nanofiltration membrane becomes smaller due to the accumulation of impurities during the working process, the passage rate of the solvent to be separated is greatly reduced. The present invention can extend the service life of the nanofiltration membrane and reduce the number of times the nanofiltration membrane is cleaned and replaced by gradually increasing the temperature during use, which can not only reduce the cost of use, but also improve the filtration efficiency. At the same time, the present invention comprises a temperature regulating jacket and a heating water tank to form a heating device for the transfer water tank, thereby ensuring the constant water temperature in the temperature regulating jacket; a middle-layer heating tube is placed in the heating water tank, and an upper-layer heating tube and a lower-layer heating tube arranged obliquely are set between adjacent middle-layer heating tubes to heat the liquid. By changing the flow direction of the liquid, the liquid is heated in multiple directions, thereby effectively improving the heating efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the structure of the present invention;

[0017] Figure 2 It is a schematic diagram of the structure of the temperature regulating jacket and the heating water tank;

[0018] Figure 3 It is a structural diagram of the lifting mechanism;

[0019] Figure 4 It is a side view of the lifting mechanism.

[0020] The markings in the accompanying drawings are: 1-raw water tank, 2-raw water booster pump, 3-ultrafiltration device, 4-transfer water tank, 5-concentrate booster pump, 6-second safety filter, 7-high pressure pump, 8-AMS nanofiltration device, 9-terminal water tank, 10-first heat conductive plate, 11-temperature regulating jacket, 12-heating water tank, 13-hot water pipe, 14-cold water pipe, 15-middle layer heating pipe, 16-upper layer heating pipe, 17-lower layer heating pipe, 18-first safety filter, 19-guide rod, 20-lifting cylinder, 21-water tank fixing seat, 22-second heat conductive plate, 23-heating groove, 24-air guide groove, 25-metal telescopic tube. DETAILED DESCRIPTION

[0021] The present invention is further described below in conjunction with the accompanying drawings and embodiments, but they are not intended to limit the present invention.

[0022] Embodiment: A solvent recovery method for high-solvent wastewater in pharmaceutical and chemical industries, wherein the high-solvent wastewater is finely filtered using a security filter and an ultrafiltration device to obtain a filtered solution; and the filtered solution is re-processed using a security filter and an AMS nanofiltration device to obtain a recovered solvent.

[0023] The service life of the AMS nanofiltration membrane is increased by gradually increasing the wastewater temperature according to the rate of decrease of the liquid outlet velocity; every time the liquid outlet velocity decreases by 5%, the wastewater temperature increases by 5°C until the wastewater temperature reaches the set threshold. It is used to adjust the pore size of the AMS nanofiltration membrane in the AMS nanofiltration device to prevent the nanofiltration membrane from being blocked and extend the service life of the nanofiltration membrane.

[0024] A solvent recovery system for high-solvent wastewater in pharmaceutical and chemical industries, comprising: Figures 1 to 4 As shown, it includes a raw water tank 1, which is connected to a raw water booster pump 2, a first safety filter 18 and an ultrafiltration device 3 in sequence through pipelines, a water outlet of the ultrafiltration device 3 is connected to a transfer water tank 4 through a pipeline, and a return water outlet of the ultrafiltration device 3 is connected to the raw water tank 1 through a pipeline; the transfer water tank 4 is connected to a concentrate booster pump 5, a second safety filter 6, a high-pressure pump 7 and an AMS nanofiltration device 8 in sequence through pipelines, a water outlet of the AMS nanofiltration device 8 is connected to a terminal water tank 9 through a pipeline, and a return water outlet of the AMS nanofiltration device 8 is connected to the transfer water tank 4 through a pipeline.

[0025] The transfer water tank 4 is a cylindrical tank; the inner wall of the transfer water tank 4 is provided with a spirally distributed first heat conducting sheet 10. The first heat conducting sheet is also provided with a flow hole to facilitate the flow of water. By providing the first heat conducting sheet, on the one hand, the purpose of rapid heat conduction can be achieved, and on the other hand, it can also play the purpose of turbulence, prevent sedimentation, and improve the uniformity of mixing.

[0026] A temperature regulating jacket 11 is also provided outside the transfer water tank 4, and a heating water tank 12 is provided at the bottom of the temperature regulating jacket 11; a hot water inlet is provided at the lower end of the temperature regulating jacket 11, and the hot water inlet is connected to the water outlet of the heating water tank 12 through a hot water pipe 13; a cold water outlet is provided at the upper end of the temperature regulating jacket 11, and the cold water outlet is connected to the water inlet of the heating water tank 12 through a cold water pipe 14.

[0027] The hot water pipe 13 is provided with a water delivery pump.

[0028] A group of evenly distributed middle layer heating tubes 15 are provided in the middle layer of the heating water tank 12 , and upper layer heating tubes 16 and lower layer heating tubes 17 are provided between adjacent middle layer heating tubes 15 .

[0029] The lower heating tube 17 and the upper heating tube 16 are both arranged tilted, with the tilt angle being 40-50 degrees.

[0030] The transfer water tank 4 is fixed to the ground via a support; a lifting mechanism is provided at the bottom of the heating water tank 12; the lifting mechanism includes a plurality of guide rods 19 symmetrically arranged on the side walls of the heating water tank 12, a lifting cylinder 20 is provided at the bottom of the heating water tank 12, and a water tank fixing seat 21 is provided at the output end of the lifting cylinder 20; a group of evenly arranged second heat conducting plates 22 are provided on the bottom surface of the temperature regulating jacket 11, and a heating groove 23 corresponding to the position of the second heat conducting plates 22 is provided on the upper end surface of the heating water tank 12; the cross-section of the second heat conducting plates 22 is a trapezoidal structure; and air guide grooves 24 are provided between adjacent second heat conducting plates 22.

[0031] The hot water pipe 13 and the cold water pipe 14 are both provided with metal telescopic pipes 25 .

[0032] By setting up a lifting mechanism, the distance between the heating water tank and the temperature regulating jacket can be flexibly adjusted, thereby achieving rapid temperature regulation and improving the accuracy of temperature regulation. When the second heat conducting sheet is in contact with the heating groove, the contact area can be increased and the heating speed can be improved; when the second heat conducting sheet is separated from the heating groove, the temperature can be regulated by the outside air, and an air guide groove is set between adjacent second heat conducting sheets, which can not only play a role in guiding flow, but also increase wind speed and improve the cooling speed.

[0033] The working process of the present invention is as follows: the wastewater containing solvent in the workshop is sent into the raw water tank, and the wastewater is pressurized by the raw water booster pump, and the wastewater is sent to the first security filter and the ultrafiltration device for ultrafiltration precision filtration to remove impurities below about 0.03 microns in the wastewater. Subsequently, the treated concentrated solution is sent to the transfer water tank, and the concentrated solution is sent to the second security filter for filtration in turn under the action of the concentrated solution booster pump, and is sent to the AMS nanofiltration device for filtration under the action of the high-pressure pump. Under the selective permeability characteristics of the AMS-Nano-ProS-3011-2540 solvent-stabilized nanofiltration membrane, the water molecules and solvent organic matter in the concentrated solution pass through the membrane under the action of the axial piston pump 6.0MPa and converge in the water production side, with a water production of about 50L / h, and the remaining substances are concentrated on the return water side.

[0034] A water flow meter is installed in the pipeline connecting the terminal water tank and the AMS nanofiltration device. When the water flow meter detects, every time the liquid outlet speed drops by 5%, the wastewater temperature is controlled to increase by 5 degrees Celsius. When the temperature reaches the set threshold, the controller will control the heating tube to stop heating, and the AMS nanofiltration membrane needs to be replaced. The results are shown in Table 1 below.

[0035] Table 1. Comparison of purification effects

[0036]

[0037] Take two AMS nanofiltration devices with similar nanofiltration membrane blockage conditions

[0038] Reference example: The water temperature of the AMS nanofiltration device was controlled to be fixed at room temperature 25°C, and other parameters were adjusted in accordance with the present invention. A solvent recovery test was conducted, and the results are shown in Table 2 below.

[0039] Table 2. Comparison of purification effects

[0040]

[0041] The results show that the embodiments of the present invention can significantly increase the service life of the AMS nanofiltration membrane while ensuring that the obtained dichloromethane has a high purity.

Claims

1. A solvent recovery method for high-solvent wastewater in pharmaceutical and chemical industries, characterized by: The high-solvent wastewater is finely filtered using a security filter and an ultrafiltration device to obtain a filtered solution; the filtered solution is re-processed using a security filter and an AMS nanofiltration device to obtain a recovered solvent; During the use of the AMS nanofiltration device, the service life of the AMS nanofiltration membrane is increased by gradually increasing the wastewater temperature according to the rate of decrease of the liquid outlet velocity; every time the liquid outlet velocity decreases by 5%, the wastewater temperature increases by 5°C until the wastewater temperature reaches the set threshold; The invention comprises a raw water tank (1), wherein the raw water tank (1) is connected to a raw water booster pump (2), a first safety filter (18) and an ultrafiltration device (3) in sequence via a pipeline; the water outlet of the ultrafiltration device (3) is connected to a transfer water tank (4) via a pipeline; the water return port of the ultrafiltration device (3) is connected to the raw water tank (1) via a pipeline; the transfer water tank (4) is connected to a concentrate booster pump (5), a second safety filter (6), a high-pressure pump (7) and an AMS nanofiltration device (8) in sequence via a pipeline; the water outlet of the AMS nanofiltration device (8) is connected to a terminal water tank (9) via a pipeline; and the water return port of the AMS nanofiltration device (8) is connected to the transfer water tank (4) via a pipeline; The transfer water tank (4) is a cylindrical tank body; the inner wall of the transfer water tank (4) is provided with a spirally distributed first heat conducting sheet (10); The transfer water tank (4) is also provided with a temperature regulating jacket (11) outside, and a heating water tank (12) is provided at the bottom of the temperature regulating jacket (11); a hot water inlet is provided at the lower end of the temperature regulating jacket (11), and the hot water inlet is connected to the water outlet of the heating water tank (12) via a hot water pipe (13); a cold water outlet is provided at the upper end of the temperature regulating jacket (11), and the cold water outlet is connected to the water inlet of the heating water tank (12) via a cold water pipe (14); the transfer water tank (4) is fixed to the ground via a support; a lifting mechanism is provided at the bottom of the heating water tank (12); the lifting mechanism includes The invention comprises a plurality of guide rods (19) symmetrically arranged on the side wall of a heating water tank (12); a lifting cylinder (20) is provided at the bottom of the heating water tank (12); and a water tank fixing seat (21) is provided at the output end of the lifting cylinder (20); a group of evenly arranged second heat conducting plates (22) are provided on the bottom surface of the temperature regulating jacket (11); a heating groove (23) corresponding to the position of the second heat conducting plates (22) is provided on the upper end surface of the heating water tank (12); the cross section of the second heat conducting plates (22) is a trapezoidal structure; and air guide grooves (24) are provided between adjacent second heat conducting plates (22).

2. A solvent recovery method for pharmaceutical and chemical high-solvent wastewater according to claim 1, characterized in that: The hot water pipe (13) is provided with a water delivery pump.

3. A solvent recovery method for pharmaceutical and chemical high-solvent wastewater according to claim 1, characterized in that: A group of evenly distributed middle layer heating tubes (15) are provided in the middle layer of the heating water tank (12), and upper layer heating tubes (16) and lower layer heating tubes (17) are provided between adjacent middle layer heating tubes (15) and are distributed up and down.

4. A solvent recovery method for pharmaceutical and chemical high-solvent wastewater according to claim 3, characterized in that: The lower layer heating tube (17) and the upper layer heating tube (16) are both arranged in an inclined manner, with an inclination angle of 40-50 degrees.

5. A solvent recovery method for pharmaceutical and chemical high-solvent wastewater according to claim 1, characterized in that: The hot water pipe (13) and the cold water pipe (14) are both provided with a metal telescopic pipe (25).

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