CN117924082A - Method and device for controlling benzene content in vinyl acetate - Google Patents
Method and device for controlling benzene content in vinyl acetate Download PDFInfo
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- CN117924082A CN117924082A CN202410073596.1A CN202410073596A CN117924082A CN 117924082 A CN117924082 A CN 117924082A CN 202410073596 A CN202410073596 A CN 202410073596A CN 117924082 A CN117924082 A CN 117924082A
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- vinyl acetate
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- styrene
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- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 title claims abstract description 93
- XTXRWKRVRITETP-UHFFFAOYSA-N Vinyl acetate Chemical compound CC(=O)OC=C XTXRWKRVRITETP-UHFFFAOYSA-N 0.000 title claims abstract description 90
- 238000000034 method Methods 0.000 title claims abstract description 24
- 238000000926 separation method Methods 0.000 claims abstract description 30
- 238000003860 storage Methods 0.000 claims abstract description 16
- 239000012295 chemical reaction liquid Substances 0.000 claims abstract description 15
- 238000000746 purification Methods 0.000 claims abstract description 14
- 239000000203 mixture Substances 0.000 claims abstract description 5
- 238000002156 mixing Methods 0.000 claims abstract description 3
- 238000004821 distillation Methods 0.000 claims description 26
- WRPYDXWBHXAKPT-UHFFFAOYSA-N (2-ethenylphenyl) acetate Chemical compound CC(=O)OC1=CC=CC=C1C=C WRPYDXWBHXAKPT-UHFFFAOYSA-N 0.000 claims description 14
- 238000010992 reflux Methods 0.000 claims description 13
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 claims description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 8
- 239000002826 coolant Substances 0.000 claims description 7
- 238000004519 manufacturing process Methods 0.000 abstract description 5
- 239000007788 liquid Substances 0.000 description 18
- 238000009835 boiling Methods 0.000 description 6
- 239000012535 impurity Substances 0.000 description 5
- HSFWRNGVRCDJHI-UHFFFAOYSA-N alpha-acetylene Natural products C#C HSFWRNGVRCDJHI-UHFFFAOYSA-N 0.000 description 4
- 125000002534 ethynyl group Chemical group [H]C#C* 0.000 description 4
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 3
- XEKOWRVHYACXOJ-UHFFFAOYSA-N Ethyl acetate Chemical compound CCOC(C)=O XEKOWRVHYACXOJ-UHFFFAOYSA-N 0.000 description 3
- 239000004372 Polyvinyl alcohol Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 229920002451 polyvinyl alcohol Polymers 0.000 description 3
- IKHGUXGNUITLKF-UHFFFAOYSA-N Acetaldehyde Chemical compound CC=O IKHGUXGNUITLKF-UHFFFAOYSA-N 0.000 description 2
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 2
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 2
- 239000005977 Ethylene Substances 0.000 description 2
- 150000001299 aldehydes Chemical class 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- DHKHKXVYLBGOIT-UHFFFAOYSA-N 1,1-Diethoxyethane Chemical compound CCOC(C)OCC DHKHKXVYLBGOIT-UHFFFAOYSA-N 0.000 description 1
- 239000005997 Calcium carbide Substances 0.000 description 1
- 229920002978 Vinylon Polymers 0.000 description 1
- 239000011354 acetal resin Substances 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- MLUCVPSAIODCQM-NSCUHMNNSA-N crotonaldehyde Chemical compound C\C=C\C=O MLUCVPSAIODCQM-NSCUHMNNSA-N 0.000 description 1
- MLUCVPSAIODCQM-UHFFFAOYSA-N crotonaldehyde Natural products CC=CC=O MLUCVPSAIODCQM-UHFFFAOYSA-N 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000003973 paint Substances 0.000 description 1
- 229920006324 polyoxymethylene Polymers 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 238000007086 side reaction Methods 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- CLZWAWBPWVRRGI-UHFFFAOYSA-N tert-butyl 2-[2-[2-[2-[bis[2-[(2-methylpropan-2-yl)oxy]-2-oxoethyl]amino]-5-bromophenoxy]ethoxy]-4-methyl-n-[2-[(2-methylpropan-2-yl)oxy]-2-oxoethyl]anilino]acetate Chemical compound CC1=CC=C(N(CC(=O)OC(C)(C)C)CC(=O)OC(C)(C)C)C(OCCOC=2C(=CC=C(Br)C=2)N(CC(=O)OC(C)(C)C)CC(=O)OC(C)(C)C)=C1 CLZWAWBPWVRRGI-UHFFFAOYSA-N 0.000 description 1
- 229920006163 vinyl copolymer Polymers 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Landscapes
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention discloses a method and a device for controlling benzene content in vinyl acetate, which relate to the technical field of vinyl acetate production, and the method comprises the following steps: firstly, introducing vinyl acetate reaction liquid produced by a fixed bed into a coarse separation tower, shunting part of vinyl acetate in the coarse separation tower into a rectification tower A, mixing the rest distilled vinyl acetate with recycled vinyl acetate, and then feeding the mixture into a high-styrene vinyl acetate purification tower; introducing the bottom distillate in the rectifying tower A into a rectifying tower B for continuous rectification, and introducing the top distillate into a high-benzene vinyl acetate purifying tower; feeding the bottoms in the rectifying column B into a high-styrene acetate purifying column, and introducing the overhead into a low-styrene acetate storage tank; the vinyl acetate can be separated into the vinyl acetate and the low-styrene vinyl acetate through twice rectification, and the use requirements of different clients can be met.
Description
Technical Field
The invention relates to the technical field of vinyl acetate production, in particular to a method for controlling benzene content in vinyl acetate.
Background
Vinyl acetate is widely used for producing a series of chemical and chemical fiber products such as polyvinyl alcohol, paint, slurry, adhesive, vinylon, film, vinyl copolymer resin, acetal resin and the like, and the application thereof relates to various industries. As an intermediate raw material of polyvinyl alcohol, PVA varieties are currently widely demanded, and high-quality vinyl acetate is more required to be supplied as a raw material.
In the prior art, the vinyl acetate production mainly comprises an ethylene gas phase method and an acetylene gas phase method, the ethylene method has high vinyl acetate quality and better economic benefit than the acetylene method, but in some areas with rich calcium carbide resources, the acetylene method still has certain regional advantages.
The acetylene method for producing vinyl acetate is divided into a fixed bed method and a fluidized bed method, wherein the aldehyde content of the fixed bed is obviously reduced compared with that of the fluidized bed, but the benzene content of a side reaction product is increased, and the activity and downstream application of the vinyl acetate are also influenced.
Disclosure of Invention
The invention aims to provide a method for controlling benzene content in vinyl acetate, which solves the following technical problems:
in the production of vinyl acetate by a fixed bed process, how to reduce the benzene content in vinyl acetate.
The aim of the invention can be achieved by the following technical scheme:
A method for controlling benzene content in vinyl acetate comprising the steps of:
The first step: introducing the vinyl acetate reaction liquid produced by the fixed bed into a coarse separation tower, shunting part of vinyl acetate in the coarse separation tower into a rectification A tower, mixing the rest distilled vinyl acetate with recycled vinyl acetate, and then feeding the mixture into a high-styrene vinyl acetate purification tower;
And a second step of: introducing the bottom distillate in the rectifying tower A into a rectifying tower B for continuous rectification, and introducing the top distillate into a high-benzene vinyl acetate purifying tower;
and a third step of: the bottoms from column B is sent to a high styrene purification column and the overhead is introduced into a low styrene storage tank.
In a further aspect of the invention: in the rectification A tower, part of the distillate at the top of the tower needs to be led out to flow back to the rectification A tower for repeated rectification, and the reflux ratio is 1.8+/-0.2.
In a further aspect of the invention: the feeding temperature of partial vinyl acetate in the crude separation tower is 38+/-1 ℃ when the partial vinyl acetate in the crude separation tower is shunted into the rectification tower A.
In a further aspect of the invention: the heat source of the rectifying tower A is steam, and the temperature of the sensitive plate is controlled to be 68+/-1 ℃.
In a further aspect of the invention: in the rectifying column B, it is necessary to draw out a part of the reflux of the overhead into the rectifying column B for repeated rectification, and the reflux ratio is 0.7.+ -. 0.2.
In a further aspect of the invention: the heat source of the rectifying tower B is steam, and the temperature of the sensitive plate is controlled to be 75+/-1 ℃.
In a further aspect of the invention: the condensers of the rectification A tower and the rectification B tower are used as cooling mediums through circulating water.
An apparatus for controlling benzene content in vinyl acetate as above, comprising a crude separation column, a rectification column a, a rectification column B, a high styrene acetate purification column and a low styrene acetate storage tank, wherein:
The split pipe of the rough separation tower is connected with the feed inlet of the rectification A tower;
the top of the rectifying tower A is provided with a condenser A and a distillation tank A, and the distillation tank A is connected with a high-styrene acetate purifying tower through a pump body A1; the bottom discharge port of the rectifying tower A is connected with the feed port of the rectifying tower B through a pump body A2;
The top of the rectifying tower B is provided with a condenser B and a distillation tank B, and the distillation tank B is connected with a low-styrene acetate storage tank through a pump body B1; the bottom discharge port of the rectifying tower B is connected with a high styrene acetate purifying tower through a pump body B2.
In a further aspect of the invention: the distillation tank A is connected with a feed inlet of the rectifying tower A; the distillation tank B is connected with a feed inlet of the rectifying tower B.
The invention has the beneficial effects that:
The invention divides the crude vinyl acetate distilled from the crude separation tower, and carries out secondary rectification on the divided liquid, because the boiling point of the vinyl acetate is smaller than that of benzene, the temperature of a sensitive plate of a rectification tower A is controlled to be 68+/-1 ℃ during rectification, the temperature is smaller than that of the vinyl acetate and the benzene, and the low-boiling-point impurity composition in the vinyl acetate can be distilled from the top of the tower, and the vinyl acetate and the benzene can be distilled from the bottom of the tower; in the rectifying tower B, the temperature of a sensitive plate of the rectifying tower B is controlled to be 75+/-1 ℃, and the temperature is higher than the boiling point of vinyl acetate and lower than the boiling point of benzene, so that the vinyl acetate can be distilled out from the tower top, and the benzene can be distilled out from the tower bottom, so that the low-styrene vinyl acetate can be obtained from the tower top, the quality of the vinyl acetate can be further improved, and the requirements of high-end customers can be met; and meanwhile, other components in the secondary rectification process are recycled and enter a high-styrene acetate purifying tower for purification, so that the resource waste is avoided.
Drawings
The invention is further described below with reference to the accompanying drawings.
Fig. 1 is a schematic structural view of embodiment 1 in the present invention.
In the figure: 1. a rectifying tower A; 2. a condenser A; 3. a distillation tank A; 4. a pump body A1; 5. a pump body A2; 6. rectifying a B tower; 7. a condenser B; 8. a distillation tank B; 9. a pump body B1; 10. pump body B2.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Example 1
As shown in fig. 1, the invention discloses a device for controlling benzene content in vinyl acetate, which comprises a rough separation tower, a rectification tower a1, a rectification tower B6, a high-styrene acetate purifying tower and a low-styrene acetate storage tank, wherein:
the feeding port of the rough separation tower is connected with the reaction liquid outlet of the fixed bed for producing vinyl acetate, the discharging port of the rough separation tower is provided with a split pipe, and the split pipe is connected with the feeding port of the rectifying tower A1;
The top of the rectifying tower A1 is provided with a condenser A2 and a distillation tank A3, and the distillation tank A3 is connected with a high-styrene acetate purifying tower through a pump body A14 and is also connected with a feed inlet of the rectifying tower A1; the bottom discharge port of the rectifying tower A1 is connected with the feed port of the rectifying tower B6 through a pump body A25;
the top of the rectifying tower B6 is provided with a condenser B7 and a distillation tank B8, and the distillation tank B8 is connected with a low-styrene acetate storage tank through a pump body B19 and is also connected with a feed inlet of the rectifying tower A1; the bottom discharge port of the rectifying tower B6 is connected with a high styrene acetate purifying tower through a pump body B210.
The trend of the vinyl acetate reaction liquid in the device is as follows:
After the vinyl acetate reaction liquid generated by the fixed bed is firstly fed into a rough separation tower and subjected to rough separation, a large part of vinyl acetate liquid and recycled vinyl acetate are fed into a high-styrene acetate purification tower together, a small part of vinyl acetate liquid is fed into a rectification A tower 1 from a return pipe, the rectification A tower 1 is subjected to rectification, a gas phase at the top of the rectification A tower 1 is fed into a condenser A2 to be condensed into liquid and fed into a distillation tank A3, wherein part of liquid in the distillation tank A3 is pumped into the high-styrene acetate purification tower through a pump body A14, and the liquid is returned into the rectification A tower 1 for repeated rectification; the distillate at the bottom of the rectifying tower A1 is pumped into the rectifying tower B6 through the pump body A25;
the distillate at the bottom of the rectifying tower A1 is pumped into a rectifying tower B6 through a pump body A25 and then subjected to secondary rectification, the gas phase at the top of the rectifying tower B6 enters a condenser B7 to be condensed into liquid and enters a distilling tank B8, wherein part of the liquid in the distilling tank B8 is pumped into a low-styrene acetate storage tank through a pump body B19, and part of the liquid is refluxed into the rectifying tower B6 to be rectified repeatedly; the distillate at the bottom of the rectifying tower B6 is pumped into a high styrene acetate purifying tower through a pump body B210.
Example 2
The vinyl acetate liquid from the fixed bed was treated using the apparatus of example 1.
Introducing vinyl acetate reaction liquid into a rough separation tower, introducing part of the reaction liquid into a rectification A tower from a shunt pipe after rough separation, and introducing the rest of the reaction liquid into a high-styrene acetate purification tower; the feeding amount entering the rectifying tower A is controlled to be 5.6m 3/h by an adjusting valve, the feeding temperature is 37 ℃, steam is used as a heat source of the rectifying tower A, the temperature of a sensitive plate of the steam is controlled to be 67 ℃, the gas phase at the top of the tower enters a condenser A, circulating water is used as a cooling medium, distilled condensate enters a distillation tank A and then is partially sent to a high-styrene acetate purifying tower through a pump body A1, and partial condensate flows back to the rectifying tower A for repeated rectification, wherein the reflux ratio is 1.6; vinyl acetate from the bottom of the rectifying tower A is sent into a rectifying tower B through a pump body A2, steam is used as a heat source of the rectifying tower B, the temperature of a sensitive plate of the steam is controlled to be 74 ℃, gas phase at the top of the tower enters a condenser B, circulating water is used as a pit cooling medium, distilled condensate enters a distillation tank B and then is sent to a low-styrene acetate storage tank through a pump body B1 to be partially returned to the rectifying tower B for repeated rectification, and the reflux ratio is 0.5; vinyl acetate from the bottom of the rectifying tower B is sent into a high-styrene-acetate purifying tower through a pump body A2.
Wherein the vinyl acetate obtained in the low-styrene-acetate storage tank is low-styrene-acetate; the vinyl acetate liquid from the rough separation tower, the rectifying tower A and the rectifying tower B is collected in the high-styrene acetate purifying tower, and the high-styrene acetate purifying tower is used for purifying the vinyl acetate liquid to obtain the high-styrene acetate.
Example 3
The vinyl acetate liquid from the fixed bed was treated using the apparatus of example 1.
Introducing vinyl acetate reaction liquid into a rough separation tower, introducing part of the reaction liquid into a rectification A tower from a shunt pipe after rough separation, and introducing the rest of the reaction liquid into a high-styrene acetate purification tower; the feeding amount entering the rectifying tower A is controlled to be 5.6m 3/h by an adjusting valve, the feeding temperature is 38 ℃, steam is used as a heat source of the rectifying tower A, the temperature of a sensitive plate of the steam is controlled to be 68 ℃, the gas phase at the top of the tower enters a condenser A, circulating water is used as a cooling medium, distilled condensate enters a distillation tank A and is sent to a high-styrene acetate purifying tower through a pump body A1 partially, and partial condensate flows back to the rectifying tower A for repeated rectification, wherein the reflux ratio is 1.8; vinyl acetate from the bottom of the rectifying tower A is sent into a rectifying tower B through a pump body A2, steam is used as a heat source of the rectifying tower B, the temperature of a sensitive plate of the steam is controlled to be 75 ℃, gas phase at the top of the tower enters a condenser B, circulating water is used as a pit cooling medium, distilled condensate enters a distillation tank B and then is sent to a low-styrene acetate storage tank through a pump body B1 to be partially returned to the rectifying tower B for repeated rectification, and the reflux ratio is 0.7; vinyl acetate from the bottom of the rectifying tower B is sent into a high-styrene-acetate purifying tower through a pump body A2.
Wherein the vinyl acetate obtained in the low-styrene-acetate storage tank is low-styrene-acetate; the vinyl acetate liquid from the rough separation tower, the rectifying tower A and the rectifying tower B is collected in the high-styrene acetate purifying tower, and the high-styrene acetate purifying tower is used for purifying the vinyl acetate liquid to obtain the high-styrene acetate.
Example 4
The vinyl acetate liquid from the fixed bed was treated using the apparatus of example 1.
Introducing vinyl acetate reaction liquid into a rough separation tower, introducing part of the reaction liquid into a rectification A tower from a shunt pipe after rough separation, and introducing the rest of the reaction liquid into a high-styrene acetate purification tower; the feeding amount entering the rectifying tower A is controlled to be 5.6m 3/h by an adjusting valve, the feeding temperature is 39 ℃, steam is used as a heat source of the rectifying tower A, the temperature of a sensitive plate of the steam is controlled to be 69 ℃, the gas phase at the top of the tower enters a condenser A, circulating water is used as a cooling medium, distilled condensate enters a distillation tank A and then is partially sent to a high-styrene acetate purifying tower through a pump body A1, and partial condensate flows back to the rectifying tower A for repeated rectification, wherein the reflux ratio is 2; vinyl acetate from the bottom of the rectifying tower A is sent into a rectifying tower B through a pump body A2, steam is used as a heat source of the rectifying tower B, the temperature of a sensitive plate of the steam is controlled to be 76 ℃, a gas phase at the top of the tower enters a condenser B, circulating water is used as a pit cooling medium, distilled condensate enters a distillation tank B and is sent to a low-styrene acetate storage tank through a pump body B1 to be partially returned to the rectifying tower B for repeated rectification, and the reflux ratio is 0.9; vinyl acetate from the bottom of the rectifying tower B is sent into a high-styrene-acetate purifying tower through a pump body A2.
Wherein the vinyl acetate obtained in the low-styrene-acetate storage tank is low-styrene-acetate; the vinyl acetate liquid from the rough separation tower, the rectifying tower A and the rectifying tower B is collected in the high-styrene acetate purifying tower, and the high-styrene acetate purifying tower is used for purifying the vinyl acetate liquid to obtain the high-styrene acetate.
The low styrene acetate and the high styrene acetate obtained in examples 2 to 4 were each examined, and the results of examination of the low styrene acetate are shown in Table 1, and the results of examination of the high styrene acetate are shown in Table 2, and tables 1 to 2 are as follows:
TABLE 1
| Analysis item | Example 2 | Example 3 | Example 4 |
| Appearance of | Colorless and transparent, free of mechanical impurities | Colorless and transparent, free of mechanical impurities | Colorless and transparent, free of mechanical impurities |
| Moisture, percent | 0.009 | 0.009 | 0.009 |
| Ethyl acetate% | 0.002 | 0.003 | 0.002 |
| Aldehyde (calculated as acetaldehyde)% | 0.001 | 0.001 | 0.001 |
| Acidity (in acetic acid)%, percent | 0.0001 | 0.0005 | 0.0004 |
| Acetone,% | 0.001 | 0.001 | 0.001 |
| Crotonaldehyde, percent | 0.0001 | 0.0001 | 0.0001 |
| Purity of% | 99.95 | 99.94 | 99.96 |
| Activity level | 8m50s0 | 8m48s8 | 9m5s9 |
| Benzene, ppm | 0.05 | 0.1 | 0.05 |
TABLE 2
Analysis of the data in Table 1-2 shows that in examples 2-4, the low styrene acetate produced has better activity than the high styrene acetate, the benzene content is greatly reduced, and various indexes have more excellent performance because:
In the invention, during the preparation of vinyl acetate, during the step of transferring vinyl acetate from a crude separation tower to a high-styrene acetate purification tower for treatment, part of vinyl acetate from the crude separation tower is rectified twice, and the boiling point of vinyl acetate is (72.5 ℃) lower than that of benzene (80.1), so that during rectification, the temperature of a sensitive plate of a rectification tower A is controlled to be 68+/-1 ℃, and is lower than that of vinyl acetate and benzene, so that a low-boiling-point impurity composition in the vinyl acetate can be distilled from the top of the tower, and the vinyl acetate and benzene can be distilled from the bottom of the tower; in the rectifying tower B, the temperature of the sensitive plate of the rectifying tower B is controlled to be 75+/-1 ℃, and the temperature is higher than the boiling point of vinyl acetate and lower than the boiling point of benzene, so that the vinyl acetate can be distilled out from the tower top, and the benzene can be distilled out from the tower bottom, so that the low-styrene vinyl acetate can be obtained from the tower top.
In the description of the present invention, it should be understood that the terms "upper," "lower," "left," "right," and the like indicate an orientation or a positional relationship based on that shown in the drawings, and are merely for convenience of description and for simplifying the description, and do not indicate or imply that the apparatus or element in question must have a specific orientation, as well as a specific orientation configuration and operation, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present invention, unless otherwise indicated, the meaning of "a plurality" is two or more.
In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and the like are to be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.
The foregoing describes one embodiment of the present invention in detail, but the disclosure is only a preferred embodiment of the present invention and should not be construed as limiting the scope of the invention. All equivalent changes and modifications within the scope of the present invention are intended to be covered by the present invention.
Claims (9)
1. A method for controlling benzene content in vinyl acetate comprising the steps of:
The first step: introducing the vinyl acetate reaction liquid produced by the fixed bed into a coarse separation tower, shunting part of vinyl acetate in the coarse separation tower into a rectification A tower, mixing the rest distilled vinyl acetate with recycled vinyl acetate, and then feeding the mixture into a high-styrene vinyl acetate purification tower;
And a second step of: introducing the bottom distillate in the rectifying tower A into a rectifying tower B for continuous rectification, and introducing the top distillate into a high-benzene vinyl acetate purifying tower;
and a third step of: the bottoms from column B is sent to a high styrene purification column and the overhead is introduced into a low styrene storage tank.
2. The method for controlling benzene content in vinyl acetate according to claim 1, wherein in the rectifying a column, it is necessary to draw out a part of the reflux of the overhead into the rectifying a column for repeated rectification, and the reflux ratio is 1.8±0.2.
3. The method for controlling benzene content in vinyl acetate according to claim 2, wherein the feeding temperature at which part of vinyl acetate in the crude separation column is branched into the rectification a column is 38±1 ℃.
4. A method for controlling benzene content in vinyl acetate according to claim 3, wherein the heat source of the rectifying a tower is steam, and the temperature of the sensitive plate is controlled to be 68±1 ℃.
5. The method for controlling benzene content in vinyl acetate according to claim 1, wherein in the rectifying column B, it is necessary to draw out a part of the reflux of the overhead into the rectifying column B for repeated rectification, and the reflux ratio is 0.7±0.2.
6. The method for controlling benzene content in vinyl acetate according to claim 5, wherein the heat source of the rectifying column B is steam, and the temperature of the sensitive plate is controlled to be 75±1 ℃.
7. The method for controlling benzene content in vinyl acetate according to claim 1, wherein condensers of the rectification a column and the rectification B column use circulating water as a cooling medium.
8. An apparatus for use in the method for controlling benzene content in vinyl acetate according to any one of claims 1 to 7, comprising a crude separation column, a rectification a column, a rectification B column, a high styrene acetate purification column, and a low styrene acetate storage tank, wherein:
The split pipe of the rough separation tower is connected with the feed inlet of the rectification A tower;
The top of the rectifying tower A is provided with a condenser A and a distillation tank A, and the distillation tank A is connected with a high-styrene acetate purifying tower through a pump body A1; the bottom discharge port of the rectifying tower A is connected with the feed port of the rectifying tower B through a pump body A2;
the top of the rectifying tower B is provided with a condenser B and a distillation tank B, and the distillation tank B is connected with a low-styrene acetate storage tank through a pump body B1; and a discharge hole at the bottom of the rectifying tower B is connected with a high styrene acetate purifying tower through a pump body B2.
9. The device according to claim 8, wherein the distillation tank A is connected with a feed inlet of a rectification A column; and the distillation tank B is connected with a feed inlet of the rectifying tower B.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410073596.1A CN117924082A (en) | 2024-01-18 | 2024-01-18 | Method and device for controlling benzene content in vinyl acetate |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410073596.1A CN117924082A (en) | 2024-01-18 | 2024-01-18 | Method and device for controlling benzene content in vinyl acetate |
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| Publication Number | Publication Date |
|---|---|
| CN117924082A true CN117924082A (en) | 2024-04-26 |
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| CN202410073596.1A Pending CN117924082A (en) | 2024-01-18 | 2024-01-18 | Method and device for controlling benzene content in vinyl acetate |
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