Vinyl chloride recycling and refining device

Abstract

The utility model discloses a vinyl chloride recycling and refining device which comprises a polymerization kettle and an alkaline washing tower, the polymerization kettle is connected with the alkaline washing tower close to the bottom through a pipeline, the bottom of the alkaline washing tower is connected with a polymerization inhibitor tank through a return pipe, and the alkaline washing tower close to the top is connected with the polymerization inhibitor tank through a feeding pipe; the top of the alkaline washing tower is connected with a total condenser through a pipeline, the total condenser is connected with a tail condenser through a pipeline, the top of the tail condenser is connected with an emptying valve through a pipeline, the bottom of the tail condenser is connected with a decanter through a pipeline, and the decanter is connected with the total condenser through a pipeline; the decanter is connected with a dewatering unit through a pipeline, the dewatering unit is connected with a refining tower through a pipeline, the bottom of the refining tower is connected with a reboiler through a pipeline, the top of the reboiler is communicated with the refining tower close to the bottom through a pipeline, the top of the refining tower is connected with a condenser through a pipeline, and the condenser is connected with a liquid storage tank through a pipeline. The device can effectively avoid self-polymerization of the system and remove acidic impurities, inert gases, water and high-boiling residues in vinyl chloride.

Description

Technical Field

[0001] The utility model belongs to the technical field of polyvinyl chloride and relates to a vinyl chloride recovery and refining device. Background Art

[0002] After the reaction in the polymerization kettle of the polyvinyl chloride project is completed, 17% of the vinyl chloride still does not participate in the reaction and needs to be recycled and reused. At this time, the residual vinyl chloride contains some polymerization aids, inert gases, and water. The vinyl chloride with residual polymerization aids, inert gases, and water is easy to form self-polymerization in the vinyl chloride pipeline. At the same time, after this part of the vinyl chloride enters the polymerization kettle and participates in the reaction again, it is easy to cause the polymerization kettle reaction cycle to be long, the unit consumption of polymerization aids is high, which will restrict production capacity and increase the production cost of polyvinyl chloride resin. Utility Model Content

[0003] The utility model aims to provide a vinyl chloride recovery and refining device, which solves the problems existing in the prior art that vinyl chloride is easy to self-polymerize in the vinyl chloride pipeline, and polymerization aids, inert gas and water remain in the vinyl chloride.

[0004] The technical scheme adopted by the utility model is that the vinyl chloride recovery and refining device comprises a polymerization kettle and an alkali washing tower, the polymerization kettle is connected to the alkali washing tower near the bottom through a pipeline, the bottom of the alkali washing tower is connected to an inhibitor tank through a reflux pipe, and the alkali washing tower is connected to the inhibitor tank through a feed pipe near the top, and an inhibitor circulation pump is provided on the feed pipe;

[0005] The top of the alkali washing tower is connected with a full condenser through a pipeline, the full condenser is connected with a tail condenser through a pipeline, the top of the tail condenser is connected with a vent valve through a pipeline, the bottom of the tail condenser is connected with a decanter through a pipeline, the decanter is connected with the full condenser through a pipeline, the decanter and the full condenser are respectively connected with the vent valve through pipelines; the decanter is connected with a water removal unit through a pipeline, the water removal unit is connected with a refining tower through a pipeline, the bottom of the refining tower is connected with a reboiler through a pipeline, the top of the reboiler is connected with a condenser through a pipeline, and the condenser is connected with a liquid storage tank through a pipeline.

[0006] The utility model is also characterized in that:

[0007] In the vinyl chloride recovery and refining device, a high-pressure buffer tank is provided on the pipeline between the alkali washing tower and the polymerization kettle.

[0008] In the vinyl chloride recovery and refining device, an inhibitor heat exchanger is provided on the feed pipe between the alkali washing tower and the inhibitor circulation pump.

[0009] The vinyl chloride recovery and refining device, the water removal unit includes a pre-filter, the pre-filter is connected to a coalescer through a pipeline, the coalescer is connected to a buffer tank through a pipeline, the buffer tank is connected to a solid alkali dryer through a pipeline, and a refining tower feed pump is provided on the pipeline between the buffer tank and the solid alkali dryer; the pre-filter is connected to a decanter through a pipeline, and the solid alkali dryer is connected to a refining tower through a pipeline.

[0010] The vinyl chloride recovery and refining device is provided with an inhibitor addition port on the pipeline between the alkali washing tower and the full condenser, on the pipeline between the full condenser and the decanter, on the pipeline between the pre-filter and the coalescer, on the pipeline between the coalescer and the buffer tank, on the pipeline between the solid alkali dryer and the refining tower, and on the pipeline between the condenser and the liquid storage tank.

[0011] The beneficial effects of the utility model are:

[0012] 1. Improve the purity of recovered monomers.

[0013] 2. Shorten the reaction cycle of the polymerization kettle and increase production capacity.

[0014] 3. Avoid self-aggregation of the recycling system and improve system operation efficiency.

[0015] 4. Reduce the consumption of additives and reduce production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the utility model device;

[0017] Figure 2 It is a schematic diagram of the structure of the utility model device.

[0018] In the figure, 1. polymerization kettle, 2. high-pressure buffer tank, 3. alkali washing tower, 4. inhibitor tank, 5. inhibitor circulation pump, 6. inhibitor heat exchanger, 7. full condenser, 8. tail condenser, 9. decanter, 10. pre-filter, 11. coalescer, 12. buffer tank, 13. refining tower feed pump, 14. solid alkali dryer, 15. refining tower, 16. reboiler, 17. condenser, 18. liquid storage tank, 19. inhibitor addition inlet, 20. vent valve, 21. reflux pipe, 22. feed pipe. DETAILED DESCRIPTION

[0019] The utility model is described in detail below with reference to the accompanying drawings and specific implementation modes.

[0020] The utility model provides a vinyl chloride recovery and refining device, such as Figure 1 As shown, it includes a polymerization kettle 1 and an alkali washing tower 3, the polymerization kettle 1 is connected to the alkali washing tower 3 near the bottom through a pipeline, the bottom of the alkali washing tower 3 is connected to an inhibitor tank 4 through a reflux pipe 21, and the alkali washing tower 3 is connected to the inhibitor tank 4 near the top through a feed pipe 22, and an inhibitor circulation pump 5 is provided on the feed pipe 22;

[0021] like Figure 2 As shown, a high-pressure buffer tank 2 is provided on the pipeline between the alkali washing tower 3 and the polymerization kettle 1, and an inhibitor heat exchanger 6 is provided on the feed pipe 22 between the alkali washing tower 3 and the inhibitor circulation pump 5. The function of the high-pressure buffer tank 2 is to buffer the gas phase vinyl chloride coming from the polymerization kettle 1 so that it can smoothly enter the alkali washing tower 3 near the bottom. The function of the inhibitor heat exchanger 6 is to maintain the inhibitor at a suitable temperature.

[0022] The inhibitor tank 4 contains a mixed solution of weak alkaline inhibitor and water, which enters the top of the alkali washing tower 3 along the feed pipe 22 through the inhibitor circulation pump 5, neutralizes with the gaseous vinyl chloride entering near the bottom of the alkali washing tower 3, and removes acidic impurities in the vinyl chloride.

[0023] The top of the alkali washing tower 3 is connected to a full condenser 7 through a pipeline, the full condenser 7 is connected to a tail condenser 8 through a pipeline, the top of the tail condenser 8 is connected to a vent valve 20 through a pipeline, the bottom of the tail condenser 8 is connected to a decanter 9 through a pipeline, the decanter 9 is connected to the full condenser 7 through a pipeline, the decanter 9 and the full condenser 7 are respectively connected to the vent valve 20 through pipelines; the function of the vent valve 20 is to maintain the pressure balance inside the full condenser 7, the tail condenser 8 and the decanter 9. When the pressure inside the full condenser 7, the tail condenser 8 and the decanter 9 is too high, the vent valve is opened to vent the inert gas inside the full condenser 7, the tail condenser 8 and the decanter 9, and the inert gas enters the next stage of the pressure swing adsorption process.

[0024] The gaseous vinyl chloride enters the full condenser 7 through a pipeline for the first condensation, the condensed vinyl chloride enters the decanter 9 through a pipeline, the uncondensed gaseous vinyl chloride enters the tail condenser 8 through a pipeline for the second condensation, and the vinyl chloride condensed in the tail condenser 8 enters the decanter 9 through a pipeline. The liquid vinyl chloride is allowed to stand in the decanter 9, and due to the different densities of water and vinyl chloride monomer, it will be separated into layers after standing, with water in the lower layer and vinyl chloride in the upper layer.

[0025] The decanter 9 is connected to a water removal unit through a pipeline, the water removal unit is connected to a refining tower 15 through a pipeline, the bottom of the refining tower 15 is connected to a reboiler 16 through a pipeline, the top of the reboiler 16 is connected to the bottom of the refining tower 15 through a pipeline, the top of the refining tower 15 is connected to a condenser 17 through a pipeline, and the condenser 17 is connected to a liquid storage tank 18 through a pipeline.

[0026] The liquid vinyl chloride entering the refining tower 15 flows into the reboiler 16 by self-pressure and is heated to become gaseous vinyl chloride. The gaseous vinyl chloride enters the refining tower 15 and flows into the condenser 17 through a pipeline, while the high-boiling substances in the vinyl chloride remain in the reboiler 16 and are removed. The gaseous vinyl chloride flowing into the condenser 17 is condensed and enters the liquid storage tank 18 through a pipeline by self-pressure to be used in the polymerization kettle 1.

[0027] The water removal unit includes a pre-filter 10, the pre-filter 10 is connected to a coalescer 11 through a pipeline, the coalescer 11 is connected to a buffer tank 12 through a pipeline, the buffer tank 12 is connected to a solid alkali dryer 14 through a pipeline, and a refining tower feed pump 13 is provided on the pipeline between the buffer tank 12 and the solid alkali dryer 14; the pre-filter 10 is connected to the decanter 9 through a pipeline, and the solid alkali dryer 14 is connected to the refining tower 15 through a pipeline.

[0028] After standing in the decanter 9, the liquid vinyl chloride in the upper layer flows into the pre-filter 10 through the pipeline at self-pressure, and impurities such as PVC are filtered out, and then flows into the coalescer 11 through the pipeline at self-pressure. After standing, it is dehydrated again by density difference and water layering to form crude vinyl chloride, which flows into the buffer tank 12 through the pipeline, and then is pumped to the solid alkali dryer 14 through the refining tower feed pump 13. After drying and dehydration, it flows into the refining tower 15 through the pipeline.

[0029] A polymerization inhibitor adding port 19 is provided on the pipeline between the alkali washing tower 3 and the full condenser 7. After the polymerization inhibitor is added from the polymerization inhibitor adding port 19, the self-polymerization of the vinyl chloride entering the full condenser 7 can be prevented;

[0030] A polymerization inhibitor adding port 19 is provided on the pipeline between the full condenser 7 and the decanter 9. After the polymerization inhibitor is added from the polymerization inhibitor adding port 19, the self-polymerization of the vinyl chloride entering the decanter 9 can be prevented;

[0031] A polymerization inhibitor adding port 19 is provided on the pipeline between the pre-filter 10 and the coalescer 11. After the polymerization inhibitor is added from the polymerization inhibitor adding port 19, the self-polymerization of the vinyl chloride entering the coalescer 11 can be prevented.

[0032] A polymerization inhibitor inlet 19 is provided on the pipeline between the coalescer 11 and the buffer tank 12. After the polymerization inhibitor is added from the polymerization inhibitor inlet 19, the self-polymerization of the vinyl chloride entering the buffer tank 12 can be prevented.

[0033] A polymerization inhibitor adding port 19 is provided on the pipeline between the solid alkali dryer 14 and the refining tower 15. After the polymerization inhibitor is added from the polymerization inhibitor adding port 19, the self-polymerization of the vinyl chloride entering the refining tower 15 can be prevented;

[0034] A polymerization inhibitor inlet 19 is provided on the pipeline between the condenser 17 and the liquid storage tank 18. After the polymerization inhibitor is added from the polymerization inhibitor inlet 19, the self-polymerization of the vinyl chloride entering the liquid storage tank 18 can be prevented.

[0035] The working principle is:

[0036] The gaseous vinyl chloride remaining after the reaction in the polymerization kettle 1 is recovered to the high-pressure buffer tank 2 by self-pressure, and the pressurized gaseous vinyl chloride in the high-pressure buffer tank 2 enters the alkali washing tower 3; at the same time, the mixed solution of the weak alkaline inhibitor and water in the inhibitor tank 4 enters the top of the alkali washing tower 3 along the feed pipe 22 through the inhibitor circulation pump 5, and is neutralized with the gaseous vinyl chloride entering near the bottom of the alkali washing tower 3 to remove acidic impurities in the vinyl chloride.

[0037] The gaseous vinyl chloride enters the full condenser 7 through a pipeline for the first condensation, the condensed vinyl chloride enters the decanter 9 through a pipeline, the uncondensed gaseous vinyl chloride enters the tail condenser 8 through a pipeline for the second condensation, and the vinyl chloride condensed in the tail condenser 8 enters the decanter 9 through a pipeline. The liquid vinyl chloride is allowed to stand in the decanter 9, and due to the different densities of water and vinyl chloride monomer, it will be separated into layers after standing, with water in the lower layer and vinyl chloride in the upper layer.

[0038] After standing in the decanter 9, the liquid vinyl chloride in the upper layer flows into the pre-filter 10 through the pipeline at self-pressure, and impurities such as PVC are filtered out, and then flows into the coalescer 11 through the pipeline at self-pressure. After standing, it is dehydrated again by density difference and water layering to form crude vinyl chloride, which flows into the buffer tank 12 through the pipeline, and then is pumped to the solid alkali dryer 14 through the refining tower feed pump 13. After drying and dehydration, it flows into the refining tower 15 through the pipeline.

[0039] The liquid vinyl chloride entering the refining tower 15 flows into the reboiler 16 by self-pressure and is heated to become gaseous vinyl chloride. The gaseous vinyl chloride enters the refining tower 15 and flows into the condenser 17 through a pipeline, while the high-boiling substances in the vinyl chloride remain in the reboiler 16 and are removed. The gaseous vinyl chloride flowing into the condenser 17 is condensed and enters the liquid storage tank 18 through a pipeline by self-pressure to be used in the polymerization kettle 1.

[0040] Acidic impurities in vinyl chloride are removed through acid-base neutralization, and the water in the monomer is removed by utilizing the difference in density between water and vinyl chloride monomer. Finally, high-boiling substances in vinyl chloride are removed based on the difference in boiling points between vinyl chloride and high-boiling substances. At the same time, by adding an inhibitor addition port, self-polymerization of the system is effectively avoided, and finally the recovery and refining of vinyl chloride is achieved.

[0041] After the device was put into use, the self-polymerization of the system was significantly improved, and the reaction time of the single reactor of polymerization reactor 1 was shortened by an average of 20 minutes. Calculated at 8,000 hours per year, 384 more reactors were added each year, and each reactor was calculated at 32 tons, and 12,288 tons of PVC resin was produced throughout the year.

[0042] Example 1

[0043] The utility model provides a vinyl chloride recovery and refining device, such as Figure 1As shown, it includes a polymerization kettle 1 and an alkali washing tower 3, the polymerization kettle 1 is connected to the alkali washing tower 3 near the bottom through a pipeline, the bottom of the alkali washing tower 3 is connected to an inhibitor tank 4 through a reflux pipe 21, and the alkali washing tower 3 is connected to the inhibitor tank 4 near the top through a feed pipe 22, and an inhibitor circulation pump 5 is provided on the feed pipe 22;

[0044] The top of the alkali washing tower 3 is connected to a full condenser 7 through a pipeline, the full condenser 7 is connected to a tail condenser 8 through a pipeline, the top of the tail condenser 8 is connected to a vent valve 20 through a pipeline, the bottom of the tail condenser 8 is connected to a decanter 9 through a pipeline, the decanter 9 is connected to the full condenser 7 through a pipeline, the decanter 9 and the full condenser 7 are respectively connected to the vent valve 20 through pipelines; the decanter 9 is connected to a dewatering unit through a pipeline, the dewatering unit is connected to a refining tower 15 through a pipeline, the bottom of the refining tower 15 is connected to a reboiler 16 through a pipeline, the top of the reboiler 16 is connected to the refining tower 15 near the bottom through a pipeline, the top of the refining tower 15 is connected to a condenser 17 through a pipeline, and the condenser 17 is connected to a liquid storage tank 18 through a pipeline.

[0045] Example 2

[0046] On the basis of Example 1, a high-pressure buffer tank 2 is provided on the pipeline between the alkali washing tower 3 and the polymerization kettle 1. A polymerization inhibitor heat exchanger 6 is provided on the feed pipe 22 between the alkali washing tower 3 and the polymerization inhibitor circulation pump 5.

[0047] Example 3

[0048] On the basis of Example 2, the above-mentioned water removal unit includes a pre-filter 10, the pre-filter 10 is connected to the coalescer 11 through a pipeline, the coalescer 11 is connected to the buffer tank 12 through a pipeline, the buffer tank 12 is connected to the solid alkali dryer 14 through a pipeline, and a refining tower feed pump 13 is provided on the pipeline between the buffer tank 12 and the solid alkali dryer 14; the pre-filter 10 is connected to the decanter 9 through a pipeline, and the solid alkali dryer 14 is connected to the refining tower 15 through a pipeline.

[0049] An inhibitor addition port 19 is provided on the pipeline between the alkali washing tower 3 and the full condenser 7, on the pipeline between the full condenser 7 and the decanter 9, on the pipeline between the pre-filter 10 and the coalescer 11, on the pipeline between the coalescer 11 and the buffer tank 12, on the pipeline between the solid alkali dryer 14 and the refining tower 15, and on the pipeline between the condenser 17 and the liquid storage tank 18.

Claims

1. Vinyl chloride recovery and refining device, characterized in that: The invention comprises a polymerization kettle (1) and an alkali washing tower (3), wherein the polymerization kettle (1) is connected to the bottom of the alkali washing tower (3) through a pipeline, the bottom of the alkali washing tower (3) is connected to a polymerization inhibitor tank (4) through a reflux pipe (21), and the top of the alkali washing tower (3) is connected to the polymerization inhibitor tank (4) through a feed pipe (22), and the feed pipe (22) is provided with a polymerization inhibitor circulation pump (5); The top of the alkali washing tower (3) is connected to a full condenser (7) through a pipeline, the full condenser (7) is connected to a tail condenser (8) through a pipeline, the top of the tail condenser (8) is connected to a vent valve (20) through a pipeline, the bottom of the tail condenser (8) is connected to a decanter (9) through a pipeline, the decanter (9) is connected to the full condenser (7) through a pipeline, the decanter (9) and the full condenser (7) are respectively connected to the vent valve (20) through pipelines; the decanter (9) is connected to a dewatering unit through a pipeline, the dewatering unit is connected to a refining tower (15) through a pipeline, the bottom of the refining tower (15) is connected to a reboiler (16) through a pipeline, the top of the reboiler (16) is connected to a portion near the bottom of the refining tower (15) through a pipeline, the top of the refining tower (15) is connected to a condenser (17) through a pipeline, and the condenser (17) is connected to a liquid storage tank (18) through a pipeline.

2. The vinyl chloride recovery and refining device according to claim 1, characterized in that: A high-pressure buffer tank (2) is provided on the pipeline between the alkali washing tower (3) and the polymerization kettle (1).

3. The vinyl chloride recovery and refining device according to claim 1, characterized in that: A polymerization inhibitor heat exchanger (6) is provided on the feed pipe (22) between the alkali washing tower (3) and the polymerization inhibitor circulation pump (5).

4. The vinyl chloride recovery and purification device according to claim 2 or claim 3, characterized in that: The dewatering unit comprises a pre-filter (10), the pre-filter (10) is connected to a coalescer (11) via a pipeline, the coalescer (11) is connected to a buffer tank (12) via a pipeline, the buffer tank (12) is connected to a solid alkali dryer (14) via a pipeline, and a refining tower feed pump (13) is provided on the pipeline between the buffer tank (12) and the solid alkali dryer (14); the pre-filter (10) is connected to a decanter (9) via a pipeline, and the solid alkali dryer (14) is connected to a refining tower (15) via a pipeline.

5. The vinyl chloride recovery and purification device according to claim 4, characterized in that: An inhibitor addition port (19) is provided on the pipeline between the alkali washing tower (3) and the full condenser (7), on the pipeline between the full condenser (7) and the decanter (9), on the pipeline between the pre-filter (10) and the coalescer (11), on the pipeline between the coalescer (11) and the buffer tank (12), on the pipeline between the solid alkali dryer (14) and the refining tower (15), and on the pipeline between the condenser (17) and the liquid storage tank (18).

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