A vinylidene chloride saponification wastewater treatment system

Abstract

The utility model provides a kind of vinylidene chloride saponification wastewater treatment system, it is characterized in that, including sedimentation tank, the inner of sedimentation tank is equipped with baffle, the baffle is divided into feeding area and sedimentation area by sedimentation tank, baffle bottom is equipped with pass, the feeding area is equipped with baffle, the baffle is divided into first subzone and second subzone by feeding area, the first subzone bottom is connected with feed pipe, the feed pipe is connected with second subzone bottom.This utility model sets up first subzone and second subzone in sedimentation tank, by first subzone and second subzone to add wastewater and mirabilite and flocculating agent in sedimentation tank, and in the process of adding, two stirring pieces are used to stir, ensure that wastewater and mirabilite and flocculating agent are fully mixed, effectively improve sedimentation effect, after sedimentation supernatant is filtered multiple times, sodium chloride brine and impure salt are effectively recovered, and treatment effect is good.

Description

Technical Field

[0001] This utility model belongs to the field of chemical equipment technology and relates to a wastewater treatment system for vinylidene chloride saponification. Background Technology

[0002] Vinylidene chloride (VCC) is an important organic chemical raw material. The mainstream domestic production process involves the saponification reaction of trichloroethane with sodium hydroxide or calcium hydroxide. However, the calcium hydroxide saponification process generates a large amount of saponification wastewater along with VCC. This wastewater is primarily an alkaline aqueous solution containing halogenated hydrocarbons and calcium chloride. It also contains suspended solids and small amounts of metal ions introduced during the preparation of calcium hydroxide. The halogenated hydrocarbons are mainly dichloroethane, trichloroethane, vinyl chloride, and trichloroethylene. The calcium chloride content in the wastewater is approximately 10%, and the COD content is about 300-500 mg / L. This wastewater has high salt and organic matter content. Direct discharge not only fails to meet environmental protection requirements and causes environmental pollution but also wastes resources. According to the "Technical Guidelines for Wastewater Treatment in the Petrochemical Industry" (2023 edition), high-salt organic wastewater needs to achieve "near-zero discharge" and "salt resource utilization."

[0003] The main problems with existing treatment methods are that the wastewater has a high salt content and complex composition. Traditional methods are not ideal for removing ions such as calcium and magnesium, which can easily lead to scaling in subsequent treatment equipment, affecting the normal operation and service life of the treatment system. Moreover, most treatment processes can only partially remove pollutants and cannot achieve the recycling of water resources and the resource recovery of salt substances, resulting in water waste and increased treatment costs. Utility Model Content

[0004] The purpose of this invention is to address the problem of poor wastewater treatment in the production process of vinylidene chloride in the background art, and to provide a vinylidene chloride saponification wastewater treatment system.

[0005] Therefore, the present invention adopts the following technical solution: A wastewater treatment system for vinylidene chloride saponification includes: A sedimentation tank is provided with a baffle plate inside, which divides the sedimentation tank into a feeding zone and a sedimentation zone. The bottom of the baffle plate is provided with an outlet. The feeding zone is provided with a partition plate, which divides the feeding zone into a first section and a second section. The bottom of the first section is connected to a conveying pipe, which is connected to the bottom of the second section. The upper part of the side wall of the sedimentation zone is connected to a first liquid conveying pipe. A sand filter, wherein the sand filter is connected to a first infusion tube and a second infusion tube is connected to the sand filter; An activated carbon filter is connected to a second infusion tube, and the activated carbon filter is also connected to a third infusion tube. A nanofiltration membrane filter, which is connected to a third infusion tube.

[0006] Furthermore, a fourth infusion pipe is connected to the bottom of the sedimentation zone, the fourth infusion pipe is connected to a plate and frame filter press, the plate and frame filter press is connected to a return pipe, and the return pipe is connected to the side wall of the first partition.

[0007] Furthermore, a second infusion valve is provided on the fourth infusion tube.

[0008] Furthermore, the return pipe is equipped with an infusion pump.

[0009] Furthermore, a flow-slowing plate is provided near the inlet in the sedimentation zone. The flow-slowing plate is fixed to the bottom of the sedimentation zone and is arranged along the length of the inlet. The height of the flow-slowing plate is higher than the height of the inlet.

[0010] Furthermore, each of the first and second partitions is provided with a stirring component. The stirring component includes a support, a rotating shaft is provided on the support, a plurality of stirring rods are provided at the lower part of the rotating shaft, and a motor for driving the rotating shaft to rotate is connected to the top of the rotating shaft.

[0011] Furthermore, a first infusion valve is provided on the first infusion tube.

[0012] Furthermore, the nanofiltration membrane filter is connected to a fifth infusion tube, which is connected to an evaporator.

[0013] The beneficial effects of this utility model are as follows: a first zone and a second zone are set in the sedimentation tank. Wastewater, sodium sulfate, and flocculant are added to the sedimentation tank through the first zone and the second zone. During the addition process, two agitators are used to stir the mixture to ensure that the wastewater, sodium sulfate, and flocculant are fully mixed, which effectively improves the sedimentation effect. The supernatant after sedimentation is filtered multiple times to effectively recover sodium chloride brine and impurities, resulting in good treatment effect. Attached Figure Description

[0014] Figure 1 This is a schematic front view of the structure of this utility model; In the diagram, 1-sedimentation tank, 2-baffle, 3-feeding area, 301-first zone, 302-second zone, 4-sedimentation zone, 5-outlet, 6-partition, 7-feeding pipe, 8-stirring component, 801-support, 802-rotating shaft, 803-stirring rod, 804-motor, 9-first infusion pipe, 10-first infusion valve, 11-sand filter, 12-second infusion pipe, 13-activated carbon filter, 14-third infusion pipe, 15-nanofiltration membrane filter, 16-fifth infusion pipe, 17-evaporator, 18-fourth infusion pipe, 19-plate and frame filter press, 20-second infusion valve, 21-return pipe, 22-infusion pump, 23-slow flow plate. Detailed Implementation

[0015] The present invention will now be described in detail with reference to the accompanying drawings: As shown in Figure 1, a wastewater treatment system for vinylidene chloride saponification includes a sedimentation tank 1. A baffle 2 divides the sedimentation tank 1 into a feeding zone 3 and a sedimentation zone 4. An outlet 5 at the bottom of the baffle 2 connects the feeding zone 3 and the sedimentation zone 4. A partition 6 divides the feeding zone 3 into a first section 301 and a second section 302. The first section 301 is used to add saponification wastewater and sodium sulfate, while the second section 302 is used to add flocculant. A conveying pipe 7 connects to the bottom of the first section 301 and to the bottom of the second section 302. Wastewater in the first section 301 can be fed into the second section 302 through the conveying pipe 7, and then enters the sedimentation zone 4 through the outlet 5 for sedimentation. To slow the flow rate of wastewater through the inlet 5, a flow-slowing plate 23 is installed near the inlet 5 in the sedimentation zone 4. The flow-slowing plate 23 is fixed to the bottom of the sedimentation zone 4 and is set along the length of the inlet 5. The height of the flow-slowing plate 23 is higher than the height of the inlet 5. The flow-slowing plate 23 can effectively slow down the flow rate of wastewater through the inlet 5, increase the mixing time between the flocculant and the wastewater, and improve the mixing effect. A stirring element 8 is provided in each of the first zone 301 and the second zone 302. The stirring element 8 is used to stir the wastewater, so that the wastewater, sodium sulfate and flocculant are fully mixed. Specifically, the stirring element 8 includes a support 801, which is respectively set at the top of the first zone 301 and the second zone 302. The support 801 is provided with a vertically arranged rotating shaft 802. The lower part of section 2 is equipped with multiple stirring rods 803. The top of the rotating shaft 802 is connected to a motor 804 for driving the rotating shaft 802. The upper part of the side wall of the sedimentation zone 4 is connected to a first infusion pipe 9. The supernatant after sedimentation can be output through the first infusion pipe 9. The first infusion pipe 9 is equipped with a first infusion valve 10. The first infusion pipe 9 is connected to a sand filter 11, which is used to filter suspended particles contained in the supernatant. The sand filter 11 is connected to a second infusion pipe 12, which is connected to an activated carbon filter 13. The activated carbon filter 13 is used to adsorb organic matter such as dichloroethane and vinyl chloride in the wastewater. The activated carbon filter 13 is connected to a third infusion pipe 14, which is connected to a nanofiltration membrane filter 15. The nanofiltration membrane filter 15 is used to filter out impurities (calcium sulfate and a small amount of magnesium salts) from the supernatant. After filtration, sodium chloride brine and concentrate are obtained. The nanofiltration membrane filter 15 is connected to a fifth inlet pipe 16, which is connected to an evaporator 17. The concentrate can be fed into the evaporator 17 through the fifth inlet pipe 16, where it evaporates into crystals. The sodium chloride brine can be transported to relevant treatment equipment, such as an electrocatalytic oxidation reactor. The qualified brine is transported to the chlor-alkali electrolysis system as raw material to realize the recycling of water resources and salt. The bottom of the sedimentation zone 4 is connected to a fourth inlet pipe 18, which is connected to a plate and frame filter press 19. The turbid liquid after settling at the bottom of the sedimentation zone 4 can be transported to the plate and frame filter press 19 through the fourth inlet pipe 18. A second inlet valve 20 is provided on the fourth inlet pipe 18.The plate and frame filter press 19 is connected to a return pipe 21, which is connected to the side wall of the first section 301. A delivery pump 22 is also installed on the return pipe 21, which can return the filtrate after pressing back to the first section 301 for further processing.

[0016] The method of using this utility model is as follows: First, wastewater is added to the first section 301 of the feeding zone 3 in the sedimentation tank 1. Simultaneously, sodium sulfate is added and stirred by the agitator 8 to ensure uniform mixing. At the same time, the wastewater in the first section 301 is fed into the second section 302 through the conveying pipe. Meanwhile, flocculant is added to the second section 302 and thoroughly mixed with the wastewater by the agitator 8. Adding and stirring the sodium sulfate and flocculant separately ensures uniform mixing with the wastewater. The mixed wastewater then enters the sedimentation zone 4 through the outlet 5. Once the water level in the sedimentation zone 4 reaches the set level, the feeding of wastewater and sodium sulfate mixture into the first section 301 is stopped, and the feeding of flocculant into the second section 302 is also stopped. The agitator 8 is then turned off to stop stirring, and the sedimentation process continues. Water settles in sedimentation zone 4. After sedimentation, the first infusion valve 10 is opened to input the supernatant into the sand filter 11 through the first infusion pipe 9 to filter the suspended particles contained in the supernatant. The filtered supernatant is then transported to the activated carbon filter 13 through the second infusion pipe 12. The activated carbon filter 13 adsorbs organic matter such as dichloroethane and vinyl chloride in the supernatant. After removing the organic matter, the supernatant is transported to the nanofiltration membrane filter 15 through the third infusion pipe 14 to remove impurities from the supernatant. After filtration, sodium chloride brine and a concentrated solution containing impurities are obtained. The concentrated solution can be input into the evaporator 17 through the fifth infusion pipe 16 to evaporate the water in the concentrated solution. The evaporated solution can be crystallized through a crystallizer and dried after crystallization to recover all the impurities.

[0017] After the supernatant in sedimentation zone 4 is discharged, the second infusion valve 20 can be opened to transport the sludge at the bottom of sedimentation zone 4 to the plate and frame filter press 14 through the fourth infusion pipe 18 for filtration. The filtrate is then transported back to the first partition 301 for further processing through the return pipe 21 under the action of the infusion pump 22.

Claims

1. A wastewater treatment system for vinylidene chloride saponification, characterized in that, include: A sedimentation tank (1) is provided with a baffle (2) inside the sedimentation tank (1), the baffle (2) divides the sedimentation tank (1) into a feeding area (3) and a sedimentation area (4), the bottom of the baffle (2) is provided with an outlet (5), the feeding area (3) is provided with a partition, the partition divides the feeding area (3) into a first partition (301) and a second partition (302), the bottom of the first partition (301) is connected to a conveying pipe (7), the conveying pipe (7) is connected to the bottom of the second partition (302), and the upper part of the side wall of the sedimentation area (4) is connected to a first liquid delivery pipe (9); A sand filter (11) is connected to a first infusion tube (9), and a second infusion tube (12) is connected to the sand filter (11). Activated carbon filter (13), the activated carbon filter (13) is connected to the second infusion tube (12), and the activated carbon filter (13) is connected to the third infusion tube (14). Nanofiltration membrane filter (15), which is connected to the third infusion tube (14).

2. The vinylidene chloride saponification wastewater treatment system according to claim 1, characterized in that, The bottom of the sedimentation zone (4) is connected to a fourth infusion pipe (18), the fourth infusion pipe (18) is connected to a plate and frame filter press (19), the plate and frame filter press (19) is connected to a return pipe (21), and the return pipe (21) is connected to the side wall of the first partition (301).

3. The vinylidene chloride saponification wastewater treatment system according to claim 2, characterized in that, The fourth infusion tube (18) is equipped with a second infusion valve (20).

4. The vinylidene chloride saponification wastewater treatment system according to claim 2, characterized in that, The return pipe (21) is equipped with an infusion pump (22).

5. The vinylidene chloride saponification wastewater treatment system according to claim 1, characterized in that, A flow buffer plate (23) is provided in the sedimentation zone (4) near the outlet (5). The flow buffer plate (23) is fixed to the bottom of the sedimentation zone (4) and is set along the length of the outlet (5). The height of the flow buffer plate (23) is higher than the height of the outlet (5).

6. The vinylidene chloride saponification wastewater treatment system according to claim 1, characterized in that, Each of the first partition (301) and the second partition (302) is provided with a stirring component (8). The stirring component (8) includes a support (801), a rotating shaft (802) is provided on the support (801), a plurality of stirring rods (803) are provided at the lower part of the rotating shaft (802), and a motor (804) for driving the rotating shaft (802) to rotate is connected to the top of the rotating shaft (802).

7. The vinylidene chloride saponification wastewater treatment system according to claim 1, characterized in that, The first infusion tube (9) is equipped with a first infusion valve (10).

8. The vinylidene chloride saponification wastewater treatment system according to claim 1, characterized in that, The nanofiltration membrane filter (15) is connected to a fifth infusion tube (16), and the fifth infusion tube (16) is connected to an evaporator (17).

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