Ultrafiltration membrane alkali washing system for treating polymerization centrifugal mother liquor
By combining alkaline washing and steam heating, the problem of ineffective cleaning of ultrafiltration membranes has been solved, achieving efficient cleaning of ultrafiltration membranes, water conservation, and extending the service life of membrane tubes.
Patent Information
- Application Number
- CN202422653572.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-31
- Publication Date
- 2025-11-18
- Estimated Expiration
- 2034-10-31
AI Technical Summary
In the existing technology, during the treatment of mother liquor from polymerization centrifugation, the cleaning effect of ultrafiltration membranes is not obvious and frequent replacements lead to membrane tube damage, resulting in water waste and economic losses.
An alkaline washing system is adopted, which combines a washing tank, a security filter and an ultrafiltration membrane, with steam heating and alkaline solution circulation cleaning to improve the cleaning effect of the ultrafiltration membrane and enable the reuse of the washing water.
It significantly improves the cleaning effect of ultrafiltration membranes, reduces water consumption, extends membrane tube lifespan, and reduces economic losses.
Smart Images
Figure CN223555825U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model belongs to the technical field of chemical production, and particularly relates to an ultrafiltration membrane alkali washing system for treating polymerization centrifugal mother liquor water. BACKGROUND
[0002] In the production process of polyvinyl chloride (PVC) suspension polymerization, a large amount of centrifugal mother liquor water is generated, which is a liquid containing high-concentration small particles and dissolved substances obtained by using a centrifuge to separate the mixed liquid after reaction, but polymer particles of all sizes cannot be completely removed in the centrifugal separation stage, and a small amount of residual polymer particles remain in the mother liquor water. If the mother liquor water is directly discharged without effective treatment, it will cause serious pollution to the environment. Therefore, the polymerization centrifugal mother liquor water usually needs to be purified by effective treatment processes, such as biochemical treatment, membrane separation, chemical precipitation, etc., to meet the environmental discharge standards or achieve the resource utilization of wastewater.
[0003] At present, ultrafiltration membranes are widely used to separate the centrifugal mother liquor water. However, due to the high frequency of use, various pollutants in the used ultrafiltration membranes accumulate on the membrane surface or in the internal channels, resulting in a decrease in membrane flux and a decrease in interception rate, which makes it difficult for the ultrafiltration device to meet the design requirements of water production, and even eventually loses the filtration function. In order to ensure the treatment capacity of the centrifugal mother liquor water, the ultrafiltration membrane tube needs to be frequently replaced and cleaned. The original acid washing method has no obvious effect on the cleaning of the polymerization centrifugal mother liquor ultrafiltration, and at the same time, it has a negative effect on the ultrafiltration membrane, resulting in the scrap of the membrane tube, affecting the treatment capacity of the centrifugal mother liquor water, and causing serious waste of water resources and great economic losses. SUMMARY
[0004] The utility model provides a kind of ultrafiltration membrane alkali washing system for treating polymerization centrifugal mother liquor water, to solve the problem that the cleaning effect of the original acid washing method is not obvious, and at the same time, it can cause damage to the ultrafiltration membrane tube, resulting in the scrap of the membrane tube, causing serious waste of water resources and great economic losses.
[0005] The technical scheme of the utility model is as follows: an ultrafiltration membrane alkali washing system for treating polymerization centrifugal mother liquor water, characterized by comprising a cleaning tank, a security filter and an ultrafiltration membrane, the cleaning tank and the security filter are connected by a cleaning water pipe, the cleaning water pipe is connected to the bottom water inlet of the security filter, the security filter and the ultrafiltration membrane are connected by an ultrafiltration water inlet pipe, one end of the ultrafiltration water inlet pipe is connected to the top water outlet of the security filter, and the other end of the ultrafiltration water inlet pipe is connected to the water inlet of the ultrafiltration membrane.
[0006] As a further improvement of the utility model, the water outlet of the ultrafiltration membrane is connected to a water production pipe, a water production valve is provided on the water production pipe, and a water production return pipe is also provided on the water production pipe, the other end of the water production return pipe is connected to the cleaning tank, and a water production return valve is provided on the water production return pipe.
[0007] As a further improvement of this utility model, the concentrate outlet of the ultrafiltration membrane is connected to a concentrate drain pipe, the concentrate drain pipe is equipped with a concentrate drain valve, the concentrate drain pipe is also equipped with a concentrate return pipe, the other end of the concentrate return pipe is connected to the cleaning tank, and the concentrate return pipe is equipped with a concentrate return valve.
[0008] As a further improvement of this utility model, the drain outlet of the ultrafiltration membrane is connected to a drain pipe, and the drain pipe is equipped with a bottom drain valve for draining water after daily cleaning.
[0009] As a further improvement of this utility model, the cleaning tank is also connected to a feeding pipe, a steam heating pipe and a thermometer.
[0010] As a further improvement of this utility model, a cleaning pump and a cleaning water valve are sequentially provided on the cleaning water pipe along the water flow direction.
[0011] As a further improvement of this utility model, the water inlet of the security filter is also connected to a clean water pipe, and a clean water valve is provided on the clean water pipe.
[0012] The beneficial effects of this invention are as follows: By changing the traditional cleaning method, this invention cleans the ultrafiltration membrane with alkaline washing and simultaneously heats the centrifuged mother liquor water through a steam pipe, thereby increasing the water permeability pores within the ultrafiltration membrane and significantly improving the cleaning effect. The cleaning water is returned to the cleaning tank through two return water pipes, allowing for repeated recycling. This invention has a simple structure, stable operation, effectively improves the cleaning effect of the ultrafiltration membrane, saves water resources, and has great potential for widespread application. Attached Figure Description
[0013] Figure 1 This is a schematic diagram of the structure of this utility model.
[0014] In the diagram: 1-Cleaning tank, 2-Cleaning pump, 3-Cleaning water pipe, 4-Cleaning water valve, 5-Clean water pipe, 6-Clean water valve, 7-Security filter, 8-Ultrafiltration inlet pipe, 9-Product water pipe, 10-Product water valve, 11-Product water return valve, 12-Product water return pipe, 13-Ultrafiltration membrane, 14-Concentrate drain pipe, 15-Concentrate drain valve, 16-Bottom drain valve, 17-Concentrate return valve, 18-Concentrate return pipe, 19-Feeding pipe, 20-Steam heating pipe, 21-Thermometer. Detailed Implementation
[0015] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.
[0016] like Figure 1As shown, an ultrafiltration membrane alkaline washing system for treating polymer centrifugal mother liquor is characterized by comprising a washing tank 1, a security filter 7, and an ultrafiltration membrane 13. The washing tank 1 and the security filter 7 are connected by a washing water pipe 3, which is connected to the bottom inlet of the security filter 7. The security filter 7 and the ultrafiltration membrane 13 are connected by an ultrafiltration water inlet pipe 8, one end of which is connected to the top outlet of the security filter 7, and the other end of which is connected to the inlet of the ultrafiltration membrane 13.
[0017] The ultrafiltration membrane 13 has a product water outlet connected to a product water pipe 9, a product water valve 10 on the product water pipe 9, a product water return pipe 12 on the product water pipe 9, the other end of the product water return pipe 12 is connected to the cleaning tank 1, and a product water return valve 11 is provided on the product water return pipe 12.
[0018] The concentrate outlet of the ultrafiltration membrane 13 is connected to a concentrate drain pipe 14, a concentrate drain valve 15 is provided on the concentrate drain pipe 14, and a concentrate return pipe 18 is also provided on the concentrate drain pipe 14. The other end of the concentrate return pipe 18 is connected to the cleaning tank 1, and a concentrate return valve 17 is provided on the concentrate return pipe 18.
[0019] The drain outlet of the ultrafiltration membrane 13 is connected to a drain pipe, and a bottom drain valve 16 is provided on the drain pipe for draining after daily cleaning. During cleaning, the pH value of the drained water is measured through the bottom drain valve 16.
[0020] The cleaning tank 1 is also connected to a feeding pipe 19, a steam heating pipe 20, and a thermometer 21.
[0021] A cleaning pump 2 and a cleaning water valve 4 are sequentially installed on the cleaning water pipe 3 along the water flow direction.
[0022] The inlet of the security filter 7 is also connected to a clean water pipe 5, and a clean water valve 6 is installed on the clean water pipe 5.
[0023] In use, open the valve of the feed pipe 19 and add 5% alkali solution (sodium hydroxide) to the cleaning tank 1. When the liquid level reaches 70% in the cleaning tank 1, close the valve of the feed pipe 19 and open the valve on the steam heating pipe 20 at the bottom of the cleaning tank to start heating the alkali solution in the cleaning tank 1. Observe the temperature of the alkali solution with the thermometer 21 until it reaches 40℃. Close the clear water valve 6, product water valve 10, and concentrate drain valve 15. Open the bottom drain valve 16 to drain the residual water in the ultrafiltration membrane 13. After the drainage is completed, open the product water return valve 11, concentrate return valve 17, and cleaning water valve 4 in sequence to start the cleaning pump 2 to perform alkali washing on the ultrafiltration membrane 13. At the same time, start monitoring the pH value at the drain valve 16. When the drainage pH value shows strong alkalinity (generally 13-14), close the bottom drain valve 16. After the entire device has been running for 1 hour, stop the cleaning pump 2 and soak the ultrafiltration membrane tube 13 for about 30 minutes. Repeat this process 2-3 times to complete the alkaline washing process. Close the valves of the cleaning pump 2, steam heating pipe 20, return water valve 11, concentrate return water valve 17, and cleaning water valve 4. Open the clean water valve 6 and the bottom drain valve 16 to clean the ultrafiltration membrane with clean water. When the drainage pH value at the bottom drain valve 16 reaches neutral, open the product water valve 10 and the concentrate drain valve 15 in sequence, and close the bottom drain valve 16. The ultrafiltration system will start producing water normally. Manually drain the wastewater in the cleaning tank 1 to complete the cleaning of the ultrafiltration membrane.
Claims
1. An ultrafiltration membrane alkaline washing system for treating polymer centrifugal mother liquor water, characterized in that: The system includes a cleaning tank (1), a security filter (7), and an ultrafiltration membrane (13). The cleaning tank (1) and the security filter (7) are connected by a cleaning water pipe (3), which is connected to the bottom inlet of the security filter (7). The security filter (7) and the ultrafiltration membrane (13) are connected by an ultrafiltration inlet pipe (8), with one end of the ultrafiltration inlet pipe (8) connected to the top outlet of the security filter (7) and the other end connected to the inlet of the ultrafiltration membrane (13).
2. The ultrafiltration membrane alkaline washing system for treating polymer centrifugal mother liquor water according to claim 1, characterized in that: The ultrafiltration membrane (13) has a water outlet connected to a water outlet pipe (9), a water outlet valve (10) on the water outlet pipe (9), a water outlet return pipe (12) on the water outlet pipe (9), the other end of the water outlet return pipe (12) is connected to the cleaning tank (1), and a water outlet return valve (11) is provided on the water outlet return pipe (12).
3. The ultrafiltration membrane alkaline washing system for treating polymer centrifugal mother liquor water according to claim 2, characterized in that: The concentrate outlet of the ultrafiltration membrane (13) is connected to a concentrate drain pipe (14), a concentrate drain valve (15) is provided on the concentrate drain pipe (14), a concentrate return pipe (18) is also provided on the concentrate drain pipe (14), the other end of the concentrate return pipe (18) is connected to the cleaning tank (1), and a concentrate return valve (17) is provided on the concentrate return pipe (18).
4. The ultrafiltration membrane alkaline washing system for treating polymer centrifugal mother liquor water according to claim 3, characterized in that: The drain outlet of the ultrafiltration membrane (13) is connected to a drain pipe, and a bottom drain valve (16) is provided on the drain pipe.
5. The ultrafiltration membrane alkaline washing system for treating polymer centrifugal mother liquor water according to claim 1, characterized in that: The cleaning tank (1) is also connected to a feeding pipe (19), a steam heating pipe (20), and a thermometer (21).
6. The ultrafiltration membrane alkaline washing system for treating polymer centrifugal mother liquor water according to claim 1, characterized in that: The cleaning water pipe (3) is equipped with a cleaning pump (2) and a cleaning water valve (4) in sequence along the water flow direction.
7. The ultrafiltration membrane alkaline washing system for treating polymer centrifugal mother liquor water according to claim 1, characterized in that: The inlet of the security filter (7) is also connected to a clean water pipe (5), and a clean water valve (6) is provided on the clean water pipe (5).