PVC (polyvinyl chloride) polymerization wastewater process optimization treatment system

Abstract

The utility model belongs to the technical field of chemical process, and particularly discloses a PVC (polyvinyl chloride) polymerization wastewater process optimization treatment system which comprises a wastewater tank, two overflow baffles are uniformly arranged in the wastewater tank, the wastewater tank is divided into a first precipitation bin, a second precipitation bin and a third precipitation bin by the overflow baffles, a precipitation diverging pipe is arranged in the first precipitation bin, and a precipitation diverging pipe is arranged in the second precipitation bin. The wastewater tank is sequentially connected with a wastewater delivery pump, a coarse filter, a fine filter and a spiral-plate heat exchanger, and the spiral-plate heat exchanger is simultaneously connected with a wastewater stripping tower and a centrifugal mother liquor pool; according to the whole system, the wastewater is precipitated and filtered for multiple times, and the spiral plate heat exchanger is adopted, so that the stable operation of the polymerization wastewater system is realized, the maintenance and cleaning frequency of wastewater treatment equipment is reduced, and the steam consumption of the stripping tower is also reduced, thereby reducing the production cost.

Description

Technical Field

[0001] The utility model belongs to the technical field of chemical process, and in particular relates to a PVC polymerization wastewater process optimization treatment system. Background Art

[0002] In the suspension polymerization process, a large amount of centrifugal mother liquor wastewater is generated when PVC resin particles are separated from water. It contains unreacted vinyl chloride, initiator, dispersant, anti-adhesion agent and some polyvinyl chloride organic matter with low polymerization degree. Due to its complex chemical structure and poor biodegradability, in order to improve the utilization rate of polymerization wastewater, the vinyl chloride in the wastewater needs to be recovered and then transported to the next process for treatment.

[0003] Based on the solubility of vinyl chloride in water and the boiling point of vinyl chloride, the current polymerization wastewater treatment mainly adopts the wastewater stripping and direct heating to recover vinyl chloride process. However, the following problems exist during the operation of the system: the wastewater is directly fed into the stripping tower without prior impurities removal. The residual additives, vinyl chloride and solid impurities react at a certain temperature to generate other blocky compounds, which leads to scaling and clogging of the spiral plate heat exchanger, increasing the steam consumption of the stripping tower, creating safety hazards, seriously affecting the equipment operating rate, and increasing production costs.

[0004] Therefore, it is necessary to design a PVC polymerization wastewater process optimization treatment system to optimize the treatment of the wastewater before it enters the stripping tower, effectively prevent the problem of frequent equipment blockage, and reduce the steam consumption of the stripping tower. Utility Model Content

[0005] In view of the problems of the prior art, the purpose of this utility model is to provide a PVC polymerization wastewater process optimization treatment system to solve the problem of equipment blockage and subsequent system failure caused by reactions between multiple substances in the stripping tower.

[0006] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0007] A PVC polymerization wastewater process optimization treatment system comprises a wastewater tank, wherein a water outlet of the wastewater tank is connected to a wastewater delivery pump, a discharge port of the wastewater delivery pump is connected to a coarse filter, a water outlet of the coarse filter is connected to a fine filter, a water outlet of the fine filter is connected to a spiral plate heat exchanger, a liquid I outlet of the spiral plate heat exchanger is connected to a wastewater stripping tower, a discharge port of the wastewater stripping tower is connected to a liquid II inlet of the spiral plate heat exchanger, and a liquid II outlet of the spiral plate heat exchanger is connected to a centrifugal mother liquor pool; two overflow baffles are evenly arranged in the wastewater tank, and the wastewater tank is divided into a first sedimentation bin, a second sedimentation bin, and a third sedimentation bin by the overflow baffles; a sedimentation diverging pipe is provided in the first sedimentation bin.

[0008] More preferably, drain valves are provided below the first sedimentation bin, the second sedimentation bin and the third sedimentation bin of the wastewater tank.

[0009] More preferably, a nitrogen distributor is provided in the third precipitation bin, and the nitrogen distributor is connected to a nitrogen inlet valve.

[0010] More preferably, a heat exchanger inlet valve is provided between the fine filter and the spiral plate heat exchanger.

[0011] Compared with the prior art, the present invention has the following beneficial effects:

[0012] The utility model aims at the wastewater with multiple components generated after PVC polymerization. First, it precipitates the wastewater through a wastewater tank. By installing an overflow baffle in the wastewater tank, the wastewater tank is divided into three sedimentation chambers, and a sedimentation diverging pipe is installed in the water inlet pipe of the wastewater tank, so that most of the solid impurities are settled and discharged before the wastewater enters the filter.

[0013] Two-stage filtration is completed through coarse filters and fine filters, thereby reducing impurities entering the spiral plate heat exchanger and stripping tower, effectively preventing the problem of frequent blockage of the heat exchanger, and ensuring the stability and efficiency of the stripping tower in vinyl chloride recovery. At the same time, the use of large-channel spiral plate heat exchangers reduces the steam consumption of the stripping tower, thereby reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a process flow chart of the utility model;

[0015] The meanings of the accompanying figures are as follows: 1. Wastewater tank; 1-1. First sedimentation tank; 1-2. Second sedimentation tank; 1-3. Third sedimentation tank; 2. Overflow baffle; 3. Sedimentation divergence pipe; 4. Nitrogen distributor; 5. Nitrogen inlet valve; 6. Drain valve; 7. Wastewater transfer pump; 8. Coarse filter; 9. Fine filter; 10. Heat exchanger inlet valve; 11. Spiral plate heat exchanger; 12. Wastewater stripping tower; 13. Centrifugal mother liquor tank. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solutions and advantages of 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.

[0017] In the description of the utility model, it is understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the utility model and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the utility model.

[0018] As shown in Figure 1 A PVC polymer wastewater process optimization treatment system, including wastewater tank 1, two overflow baffles 2 are uniformly arranged in wastewater tank 1, wastewater tank 1 is divided into first sedimentation bin 1-1, second sedimentation bin 1-2 and third sedimentation bin 1-3 by overflow baffle 2, three bins make solid particles in wastewater precipitate gradually, reduce the solid matter content in wastewater entering stripping tower, the lower portion of first sedimentation bin 1-1, second sedimentation bin 1-2 and third sedimentation bin 1-3 of wastewater tank 1 is equipped with blowdown valve 6, and the deposited material is discharged through blowdown valve 6 regularly, to avoid blockage during conveying, a sedimentation diverging pipe 3 is arranged in first sedimentation bin 1-1, to slow down the flow rate of wastewater entering the wastewater tank, enhance the sedimentation effect of solid matter in wastewater, a nitrogen gas distributor 4 is arranged in third sedimentation bin 1-3, nitrogen gas is introduced to mix the wastewater that cannot be precipitated, to facilitate conveying, the nitrogen gas distributor 4 is connected with nitrogen gas inlet valve 5, to control the flow of nitrogen gas to the nitrogen gas distributor.

[0019] The water outlet of wastewater tank 1 is connected with wastewater conveying pump 7, the discharge outlet of wastewater conveying pump 7 is connected with coarse filter 8, the water outlet of coarse filter 8 is connected with fine filter 9, coarse filter 8 is located at the front end of fine filter 9, mainly filters large particle matter in wastewater, fine filter 9 performs secondary filtration on wastewater, the water outlet of fine filter 9 is connected with spiral plate heat exchanger 11, the liquid I outlet of spiral plate heat exchanger 11 is connected with wastewater stripping tower 12, the liquid discharge port of wastewater stripping tower 12 is connected with the liquid II inlet of spiral plate heat exchanger 11, the liquid II outlet of spiral plate heat exchanger 11 is connected with centrifugal mother liquor tank 13, spiral plate heat exchanger 11 exchanges heat with inlet and outlet tower wastewater, preheats inlet tower wastewater, reduces stripping tower steam consumption, wastewater stripping tower 12 recovers chloroethylene in wastewater by evaporation, the evaporated wastewater enters spiral plate heat exchanger 11 to perform mass transfer and heat transfer on wastewater before entering the stripping tower, and finally is conveyed to centrifugal mother liquor tank 13, centrifugal mother liquor tank 13 is located at the end of the device, collects the stripped wastewater, and conveys it to the next processing procedure, heat exchanger inlet valve 10 is arranged between fine filter 9 and spiral plate heat exchanger 11, to cut off the front section conveying wastewater when cleaning or repairing spiral plate heat exchanger 11.

[0020] The utility model discloses in the specific use, the wastewater from the each device of polymerization is through the precipitation of big -sized solid object after the dispersion pipe 3, then after the first sedimentation bin 1-1, second sedimentation bin 1-2, third sedimentation bin 1-3 secondary precipitation, open nitrogen inlet valve 5, make nitrogen distributor 4 even discharge nitrogen, realize before entering wastewater delivery pump 7 solid impurities complete most settlement discharge, and wastewater delivery pump 7 is transported to the coarse filter 8 to the fine filter 9 again, after mass transfer and heat transfer through spiral plate exchange 11, is transported to wastewater stripping column 12, after recycling vinyl chloride in wastewater, remaining wastewater is transported to centrifugal mother liquor pool 13 again through spiral plate exchange 11, is transported to the next process treatment again. The whole process through the wastewater multiple sedimentation filtration and adopt spiral plate heat exchanger after, the stable operation of polymerization wastewater system is guaranteed, reduces the maintenance and the cleaning frequency of wastewater treatment equipment, also reduces the stripping column steam consumption, thereby reduces the production cost.

[0021] The above is only the preferred embodiment of the utility model, and does not limit the utility model, and any modification, equivalent replacement and improvement, etc. within the spirit and principle of the utility model should be included in the protection scope of the utility model.

Claims

1. A PVC polymerization wastewater process optimization treatment system, including a wastewater tank, characterized by: The water outlet of the wastewater tank (1) is connected to a wastewater delivery pump (7), the discharge port of the wastewater delivery pump (7) is connected to a coarse filter (8), the water outlet of the coarse filter (8) is connected to a fine filter (9), the water outlet of the fine filter (9) is connected to a spiral plate heat exchanger (11), the liquid I outlet of the spiral plate heat exchanger (11) is connected to a wastewater stripping tower (12), the discharge port of the wastewater stripping tower (12) is connected to the liquid II inlet of the spiral plate heat exchanger (11), and the liquid II outlet of the spiral plate heat exchanger (11) is connected to a centrifugal mother liquor pool (13); two overflow baffles (2) are evenly arranged in the wastewater tank (1), and the wastewater tank (1) is divided into a first sedimentation bin (1-1), a second sedimentation bin (1-2) and a third sedimentation bin (1-3) by the overflow baffles (2); the first sedimentation bin (1-1) is provided with a sedimentation diverging pipe (3).

2. The PVC polymerization wastewater process optimization treatment system according to claim 1, characterized in that: Drain valves (6) are provided below the first sedimentation bin (1-1), the second sedimentation bin (1-2) and the third sedimentation bin (1-3) of the wastewater tank (1).

3. The PVC polymerization wastewater process optimization treatment system according to claim 1, characterized in that: A nitrogen distributor (4) is provided in the third sedimentation bin (1-3), and the nitrogen distributor (4) is connected to a nitrogen inlet valve (5).

4. The PVC polymerization wastewater process optimization treatment system according to claim 1, characterized in that: A heat exchanger inlet valve (10) is provided between the fine filter (9) and the spiral plate heat exchanger (11).

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