CN219050888U - Crystal separation system in chloroethylene alkaline washing process - Google Patents
Crystal separation system in chloroethylene alkaline washing process Download PDFInfo
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- CN219050888U CN219050888U CN202223230344.0U CN202223230344U CN219050888U CN 219050888 U CN219050888 U CN 219050888U CN 202223230344 U CN202223230344 U CN 202223230344U CN 219050888 U CN219050888 U CN 219050888U
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- alkali liquor
- alkaline
- alkali
- chloroethylene
- circulation tank
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/10—Process efficiency
Abstract
The utility model discloses a crystallization separation system in the alkali washing process of chloroethylene, which comprises an alkali liquor circulation tank and an alkali washing tower, wherein an overflow baffle is arranged in the alkali liquor circulation tank, the overflow baffle divides the alkali liquor circulation tank into a precipitation area and an overflow area, and the volume of the precipitation area is smaller than that of the overflow area; the bottom of the overflow area is connected with an alkali liquor outlet pipe, the other end of the alkali liquor outlet pipe is connected with an alkali liquor inlet arranged at the top of the alkali washing tower, and an alkali liquor circulating pump is also arranged on the alkali liquor outlet pipe; the bottom of the alkaline washing tower is provided with an alkaline liquor outlet, the alkaline liquor outlet is connected with an alkaline liquor return pipe, and the other end of the alkaline liquor return pipe extends into the alkaline liquor circulation tank and is positioned above the precipitation zone; and a drain valve is also arranged at the bottom of the sedimentation zone. The system effectively solves the problem of blockage in the alkaline washing tower, ensures long-period stable operation of the alkaline washing tower, and has better practicability.
Description
Technical Field
The utility model belongs to the technical field of vinyl chloride production, and particularly relates to a crystal separation system in a vinyl chloride alkaline washing process.
Background
In the process of producing polyvinyl chloride by a calcium carbide method, the purity of vinyl chloride monomer produced by a converter is low, and alkali washing is needed to remove acidic substances such as hydrogen chloride in the monomer. Caustic washing is a chemical absorption operation in which chemical reactions occur during absorption. Carbon dioxide and trace hydrogen chloride can be removed by alkali washing, a dilute solution of sodium hydroxide is usually used as a chemical absorbent, the alkali solution is 10-15% of sodium hydroxide solution, and the crude chloroethylene gas is subjected to alkali washing to be neutral, and the reaction equation is as follows:
2NaOH +CO 2 →Na 2 CO 3 +H 2 o+ heat quantity
HCl+NaOH→NaCl+H 2 The heat quantity of O < + >,
when NaOH is excessive, the reaction proceeds very rapidly, and the sodium bicarbonate produced can be completely converted into sodium carbonate, and carbon dioxide can be almost completely removed. If sodium hydroxide in solution has all formed sodium carbonate, then a significant amount of sodium carbonate, although still capable of absorbing carbon dioxide, reacts quite slowly as follows: na (Na) 2 CO 3 + CO 2 +H 2 O→2NaHCO 3 Because the sodium hydroxide is almost not contained in the solution, the generated sodium bicarbonate is not disappeared any more, and the sodium bicarbonate has smaller solubility in water and is easy to precipitate out, so that pipelines and equipment are blocked, and the production cannot be carried out normally.
Disclosure of Invention
Aiming at the problems in the background technology, the utility model discloses a system for separating crystals in the alkali washing process of vinyl chloride.
The utility model adopts the following technical scheme:
the crystallization separation system in the chloroethylene alkaline washing process comprises an alkali liquor circulation tank and an alkaline washing tower, wherein an overflow baffle is arranged in the alkali liquor circulation tank, the overflow baffle divides the alkali liquor circulation tank into a precipitation area and an overflow area, and the volume of the precipitation area is smaller than that of the overflow area; the bottom of the overflow area is connected with an alkali liquor outlet pipe, the other end of the alkali liquor outlet pipe is connected with an alkali liquor inlet arranged at the top of the alkali washing tower, and an alkali liquor circulating pump is also arranged on the alkali liquor outlet pipe; the bottom of the alkaline washing tower is provided with an alkaline liquor outlet, the alkaline liquor outlet is connected with an alkaline liquor return pipe, and the other end of the alkaline liquor return pipe extends into the alkaline liquor circulation tank and is positioned above the precipitation zone; and a drain valve is also arranged at the bottom of the sedimentation zone. The bottom of the alkaline washing tower is also connected with a chloroethylene inlet pipe, and the top of the alkaline washing tower is also connected with a chloroethylene outlet pipe.
Compared with the prior art, the utility model has the following beneficial effects:
according to the utility model, sodium bicarbonate can be effectively prevented from gathering in the alkaline washing tower, the overflow baffle is arranged in the alkaline liquor circulation tank, so that sodium bicarbonate is concentrated on one side of the overflow baffle by gravity sedimentation, and only one side of the overflow baffle is required to be subjected to alkali discharge replacement periodically, so that the problem of blockage in the alkaline washing tower is effectively solved, and long-period operation of the device is ensured.
Drawings
Fig. 1 is a system configuration diagram of the present utility model.
In the figure: 1-an alkali liquor circulation tank; 2-an alkaline washing tower; 3-an alkali liquor outlet pipe; 4-an alkali liquor circulating pump; 5-alkali liquor return pipe; 6-overflow baffles; 7-vinyl chloride inlet pipe; an 8-vinyl chloride outlet pipe; 9-a blow-down valve; 10-alkali liquor replenishing port.
Detailed Description
The utility model is further explained below with reference to the drawings.
As shown in fig. 1, a system for separating crystals in the alkali washing process of vinyl chloride comprises an alkali liquor circulation tank 1 and an alkali washing tower 2, wherein an overflow baffle 6 is arranged in the alkali liquor circulation tank 1, the overflow baffle 6 divides the alkali liquor circulation tank 1 into a precipitation area and an overflow area, and the volume of the precipitation area is smaller than that of the overflow area; the bottom of the overflow area is connected with an alkali liquor outlet pipe 3, the other end of the alkali liquor outlet pipe 3 is connected with an alkali liquor inlet arranged at the top of the alkali washing tower 2, and an alkali liquor circulating pump 4 is also arranged on the alkali liquor outlet pipe 3; the bottom of the alkaline washing tower 2 is provided with an alkaline liquor outlet, the alkaline liquor outlet is connected with an alkaline liquor return pipe 5, the other end of the alkaline liquor return pipe 5 extends into the alkaline liquor circulation tank 1 and is positioned above the sedimentation zone, and the bottom of the sedimentation zone is also provided with a blow-off valve 9.
In order to better neutralize acid gas mixed in the chloroethylene by the alkali liquor, the bottom of the alkali washing tower 2 is provided with a chloroethylene inlet pipe 7, and the top is provided with a chloroethylene outlet pipe 8. When the chloroethylene gas enters the alkaline washing tower 2 from the chloroethylene inlet pipe 7, the chloroethylene gas moves upwards to a filter material layer, and the chloroethylene gas and alkali liquor sprayed by a spray nozzle are subjected to neutralization reaction (a spray assembly is arranged at the top of the alkaline washing tower 2 and used for uniformly spraying the alkali liquor conveyed by the alkali liquor circulation tank 1 on the filter material layer), and the filter material layer is generally provided with a plurality of layers, so that acid gas mixed in the chloroethylene can be fully reacted and removed by using the alkali liquor. Finally, the clean chloroethylene gas is discharged from the chloroethylene outlet pipe 8 to enter the subsequent process.
In order to ensure that excessive sodium bicarbonate in the lye can be fully precipitated and separated, the height of an overflow baffle 6 in the lye circulation tank 1 is 1/2-2/3 of the height of the lye circulation tank 1.
In order to facilitate the addition of lye, the top of the overflow area of the lye circulation tank 1 is also provided with a lye addition port 10.
The working process of the utility model is as follows:
firstly, the crystallization separation system is subjected to pressurizing leakage test replacement, no leakage is required, and the oxygen content in a pipeline is less than or equal to 0.2 percent. And then opening an alkali liquor replenishing port 10, and replenishing 30% -40% sodium hydroxide solution into the alkali liquor circulation tank 1, wherein the adding amount is enough to be enough to overflow the overflow baffle 6. Then an alkali liquor circulating pump 4 is started to send alkali liquor into the alkali washing tower 2, then the valves on a chloroethylene inlet pipe 7 and a chloroethylene outlet pipe 8 are opened, chloroethylene air current mixed with acid gases such as hydrogen chloride is contacted with the alkali liquor to generate neutralization reaction, waste alkali liquor after the reaction flows into the bottom of the alkali washing tower 2 under the action of gravity and enters the alkali liquor circulating tank 1 through an alkali liquor return pipe 5, after full precipitation is carried out in a precipitation zone, supernatant liquor turns over an overflow baffle 6 to enter an overflow zone and is pumped by the alkali liquor circulating pump 4 to enter the next circulation. And (3) manually and periodically opening a blow-down valve 9 at the bottom of the sedimentation zone of the alkali liquor circulation tank 1 to discharge sodium bicarbonate and waste alkali.
Since sodium bicarbonate precipitate hardly occurs in the alkali liquor circulation tank 1 when the concentration of the sodium hydroxide solution is high at the beginning, but as the reaction proceeds gradually, precipitate occurs gradually in the alkali liquor circulation tank 1, and in order to avoid blocking caused by that part of precipitate enters the alkali wash tower 2 again along with the circulation of the alkali liquor, an overflow baffle 6 is arranged in the alkali liquor circulation tank 1 to intercept and precipitate excessive sodium hydroxide. Meanwhile, in order to ensure the neutralization and washing effects of the alkaline washing tower 2 and avoid the blocking of a filter layer, an alkaline solution supplementing port 10 is opened to supplement alkaline solution into the alkaline solution circulating tank 1 during the discharge of the sediment so as to improve the concentration of the alkaline solution.
In the working process, in order to conveniently observe the liquid level and the deposition accumulation condition in the alkali liquor circulation tank 1, the alkali liquor circulation tank 1 can be made of transparent glass fiber reinforced plastics.
The remaining non-exhaustive description uses equivalents of the prior art to perform the same function, and the above description is only a preferred embodiment of the present utility model, and is not intended to limit the utility model, and the scope of the utility model is defined by the claims.
Claims (4)
1. A crystallization separation system in the process of washing chloroethylene with alkali is characterized in that: the device comprises an alkali liquor circulation tank (1) and an alkali washing tower (2), wherein an overflow baffle (6) is arranged in the alkali liquor circulation tank (1), the overflow baffle (6) divides the alkali liquor circulation tank (1) into a precipitation area and an overflow area, and the volume of the precipitation area is smaller than that of the overflow area; the bottom of the overflow area is connected with an alkali liquor outlet pipe (3), the other end of the alkali liquor outlet pipe (3) is connected with an alkali liquor inlet arranged at the top of the alkali washing tower (2), and an alkali liquor circulating pump (4) is also arranged on the alkali liquor outlet pipe (3); the bottom of the alkaline washing tower (2) is provided with an alkaline solution outlet, the alkaline solution outlet is connected with an alkaline solution return pipe (5), the other end of the alkaline solution return pipe (5) extends into the alkaline solution circulation tank (1) and is positioned above the sedimentation zone, and the bottom of the sedimentation zone is also provided with a blow-down valve (9).
2. A system for separating crystals in a chloroethylene alkaline washing process as claimed in claim 1, wherein: the bottom of the alkaline washing tower (2) is provided with a chloroethylene inlet pipe (7), and the top of the alkaline washing tower is provided with a chloroethylene outlet pipe (8).
3. A system for separating crystals in a chloroethylene alkaline washing process as claimed in claim 1, wherein: the height of the overflow baffle (6) is one half to two thirds of the height of the alkali liquor circulation tank (1).
4. A system for separating crystals in a chloroethylene alkaline washing process as claimed in claim 1, wherein: the top of the overflow area is also provided with an alkali liquor supplementing port (10).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202223230344.0U CN219050888U (en) | 2022-12-03 | 2022-12-03 | Crystal separation system in chloroethylene alkaline washing process |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202223230344.0U CN219050888U (en) | 2022-12-03 | 2022-12-03 | Crystal separation system in chloroethylene alkaline washing process |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN219050888U true CN219050888U (en) | 2023-05-23 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202223230344.0U Active CN219050888U (en) | 2022-12-03 | 2022-12-03 | Crystal separation system in chloroethylene alkaline washing process |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN219050888U (en) |
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2022
- 2022-12-03 CN CN202223230344.0U patent/CN219050888U/en active Active
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