CN102675066B - Method for inhibiting polymerization of acetaldehyde in polyvinyl alcohol and vinyl acetate production process - Google Patents
Method for inhibiting polymerization of acetaldehyde in polyvinyl alcohol and vinyl acetate production process Download PDFInfo
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- CN102675066B CN102675066B CN201210195794.2A CN201210195794A CN102675066B CN 102675066 B CN102675066 B CN 102675066B CN 201210195794 A CN201210195794 A CN 201210195794A CN 102675066 B CN102675066 B CN 102675066B
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Abstract
The invention belongs to the field of chemical industry, and provides a method for inhibiting polymerization of acetaldehyde in a polyvinyl alcohol and vinyl acetate production process, which is implemented in a way that: in the acetaldehyde refinement and recycling process, a polymerization inhibitor is added to prevent acetaldehyde from self-polymerization, and the pH value of the acetaldehyde water solution is regulated to 4.5-5.6; and the polymerization inhibitor is a mixed solution of acetic acid and sodium acetate in a mass ratio of (0.02-0.4):1, and the addition concentration of the polymerization inhibitor is 25-2000ppm. The method provided by the invention has the advantages of favorable polymerization inhibition effect, low cost and the like, and can obviously enhance the quality of vinyl acetate and recovery rate of acetaldehyde; and the polymerization inhibitor can not be easily decomposed and has stable properties.
Description
Technical field
The invention belongs to chemical field, relate to the method for the acetaldehyde inhibition in a kind of polyvinyl alcohol (PVA) and vinyl acetate between to for plastic (VAc) production process.The invention still further relates to polyvinyl alcohol produce in the method for the refining acetaldehyde inhibition with the production process such as recovery, sodium acetate recycling of synthetic and refining, the acetaldehyde of vinyl acetate between to for plastic.
Background technology
In polyvinyl alcohol (PVA) and vinyl acetate between to for plastic (VAc) production process, the refining technical process with reclaiming of acetaldehyde is as shown in Figure 1: vinyl acetate between to for plastic 1 reaction solution containing acetaldehyde enters dealdehyder tower A, dealdehyder tower A tower reactor vinyl acetate between to for plastic and acetic acid 2 enter vinyl acetate between to for plastic treating tower B and obtain smart vinyl acetate between to for plastic 3, vinyl acetate between to for plastic and aldehydes gas 4 that dealdehyder tower A tower top distillates enter partial condenser C, vinyl acetate between to for plastic and acetaldehyde partial condensation liquid 5 return to dealdehyder tower A, part vinyl acetate between to for plastic and acetaldehyde 6 enter acetaldehyde extraction tower D, vinyl acetate between to for plastic raffinate 8 containing a small amount of acetaldehyde in acetaldehyde extraction tower D returns to dealdehyder tower A, partial condenser C top enters acetaldehyde water wash column E containing the not solidifying gas 7 of acetylene and a small amount of acetaldehyde and vinyl acetate between to for plastic, in acetaldehyde extraction tower D tower reactor containing the extraction liquid 9 of a small amount of vinyl acetate between to for plastic containing entering in acetaldehyde treating tower raw material tank F containing the acetaldehyde solution 10 of a small amount of vinyl acetate between to for plastic in the acetaldehyde solution of a small amount of vinyl acetate between to for plastic and acetaldehyde water wash column E tower reactor, acetaldehyde in acetaldehyde treating tower raw material tank F, vinyl acetate between to for plastic 12 enters acetaldehyde treating tower G, acetaldehyde treating tower G tower top distillates smart acetaldehyde 11, acetaldehyde treating tower G middle part extraction vinyl acetate between to for plastic and acetaldehyde mixed solution 13 return to acetaldehyde extraction tower D.
Acetaldehyde refining with recovery process process in often there is acetaldehyde autohemagglutination, cause that acetaldehyde treating tower overhead product acetaldehyde concentration declines to a great extent, acetaldehyde recovery rate reduces, the situation such as acetaldehyde severe overweight, the reduction of finished product polyvinyl alcohol quality in vinyl acetate between to for plastic treating tower overhead product vinyl acetate between to for plastic.And acetaldehyde autohemagglutination brings unsafe factor to oxidation of acetaldehyde operation.This is a great problem of puzzlement polyvinyl alcohol resin and vinyl acetate production enterprise always.
Researchist Wu Chuanying, the Xia Sulan of Sichuan University and China Petrochemical Industry's Sichuan vinylon plant, the stopper that Liu Hongwei proposes to make of alkali acetaldehyde, be shown in " the acetaldehyde polymerization analysis of causes and modification measures in acetic acid acetaldehyde device Ethanal distillation column "; The Liu Rui of Nanjing University of Technology river proposes to make of ammonium acetate, Triammonium citrate, hexamethylenetetramine, triethylamine the stopper of acetaldehyde, sees " research of the reason of acetaldehyde autohemagglutination and inhibition countermeasure ".The truly have certain effect of these stoppers to acetaldehyde inhibition, but also Shortcomings: such as witch passes the people such as English and does stopper with alkali, in actual production process, can cause the hydrolysis of vinyl acetate between to for plastic, affect the quality of vinyl acetate between to for plastic thereby the impurity such as generation acetaldehyde and crotonic aldehyde enter vinyl acetate between to for plastic refining system; Four kinds of ammonium salts that Liu Ruijiang proposes easily decompose in acetaldehyde treating process, and then cause the hydrolysis of vinyl acetate between to for plastic, and have introduced new impurity because the decomposition of ammonium salt makes reaction system.
Summary of the invention
For the deficiencies in the prior art, the invention provides the method for acetaldehyde inhibition in a kind of polyvinyl alcohol and vinyl acetate production process.The method adopts in and recovery process process refining at acetaldehyde adds stopper to reach the object that stops acetaldehyde autohemagglutination.Method of the present invention has compared with method in background technology that polymerization inhibition effect is good, cost is low, can significantly improve smart vinyl acetate between to for plastic quality and acetaldehyde recovery rate, stopper is difficult for the advantages such as decomposition, stable in properties.
Technical scheme of the present invention is:
A kind of method of acetaldehyde inhibition in polyvinyl alcohol and vinyl acetate production process, acetaldehyde refining with recovery process process in add stopper and prevent acetaldehyde autohemagglutination, and regulate acetaldehyde refining with recovery process process in the pH value of acetaldehyde solution in 4.5～5.6 scopes; Described stopper is the mixed solution of acetic acid and sodium-acetate, and wherein the mass ratio of acetic acid and sodium-acetate is 0.02～0.4: 1, and it is 25ppm～2000ppm that stopper adds concentration.
Described acetaldehyde refining with recovery process process in add stopper, concrete point of addition comprises acetaldehyde water wash column, acetaldehyde extraction tower, acetaldehyde treating tower or acetaldehyde treating tower raw material tank.
Described acetaldehyde refining with recovery process process in add stopper, concrete mode of adding is continuous adding or portion-wise addition, the described portion-wise addition intermittent time is 2-3 hour.
The present invention will be further explained below:
1, acetaldehyde refining with recovery process process in add acetic acid and sodium-acetate mixed solution as stopper, it forms buffered soln in acetaldehyde solution, the generation of retardance acetaldehyde polymer.Compared with the stopper of existing bibliographical information, it has advantages of and is difficult for decomposing and can cause vinyl acetate between to for plastic hydrolysis in acetaldehyde treating tower.
2, the mass ratio of acetic acid and sodium-acetate is 0.02～0.4: 1, can make the pH value in system be controlled in the scope of 4.5-5.6.If pH value is lower than 4.5, polymerization inhibition effect is poor; If pH value higher than 5.6, can cause the hydrolysis of vinyl acetate between to for plastic in acetaldehyde treating tower and generate acetaldehyde and acetic acid, and further reaction generation crotonic aldehyde of acetaldehyde.
3, in acetaldehyde solution, inhibitor concentration is controlled at best results within the scope of 25ppm～2000ppm.Inhibitor concentration is higher than 2000ppm, the stopper indifference of its polymerization inhibition effect and 2000ppm, and inhibitor concentration is lower than 25ppm, and the polymer that has acetaldehyde generates, and does not reach inhibition object.
Compared with prior art, the present invention has following advantage:
1, the selected stopper polymerization inhibition effect of the present invention is good, cost is low.
2, the selected stopper stable in properties of the present invention, compared with the stopper of existing bibliographical information: have advantages of the hydrolysis that is difficult for decomposing and can not causing vinyl acetate between to for plastic in acetaldehyde treating tower.
3, the present invention can significantly improve acetaldehyde recovery rate in polyvinyl alcohol and vinyl acetate production process.
4, the present invention can significantly reduce acetaldehyde in smart vinyl acetate between to for plastic, and smart vinyl acetate between to for plastic purity is reached more than 99.8%.
5, the present invention can significantly improve smart acetaldehyde purity, add stopper after smart acetaldehyde purity reach more than 99.5%.
Brief description of the drawings
Below in conjunction with accompanying drawing, the present invention is further elaborated.
Fig. 1 is the refining process flow sheet with reclaiming of acetaldehyde in polyvinyl alcohol and vinyl acetate production process;
In the drawings: A-dealdehyder tower, B-vinyl acetate between to for plastic treating tower, C-partial condenser, D-acetaldehyde extraction tower, E-acetaldehyde water wash column, F-acetaldehyde treating tower raw material tank, G-acetaldehyde treating tower, 1-is containing the vinyl acetate between to for plastic of acetaldehyde, 2-vinyl acetate between to for plastic and acetic acid, 3-essence vinyl acetate between to for plastic, 4-vinyl acetate between to for plastic and aldehydes gas, 5-vinyl acetate between to for plastic and acetaldehyde phlegma, 6-vinyl acetate between to for plastic and acetaldehyde, the not solidifying gas of 7-acetylene and a small amount of acetaldehyde and vinyl acetate between to for plastic, in 8-acetaldehyde extraction tower, contain the vinyl acetate between to for plastic raffinate of a small amount of acetaldehyde, in 9-acetaldehyde extraction tower tower reactor, contain the acetaldehyde solution of a small amount of vinyl acetate between to for plastic, in 10-acetaldehyde water wash column tower reactor, contain the acetaldehyde solution of a small amount of vinyl acetate between to for plastic, 11-essence acetaldehyde, 12-acetaldehyde and vinyl acetate between to for plastic, vinyl acetate between to for plastic and the acetaldehyde mixed solution of the middle part extraction of 13-acetaldehyde treating tower.
Embodiment
Describe the present invention below by embodiment, be necessary to point out that at this following examples are only for the inventive method is specifically described, and can not be interpreted as in the embodiment shown in protection domain of the presently claimed invention is strictly limited in.The personnel in this field can make some nonessential improvement and adjustment to the inventive method according to foregoing invention content.Described in the present invention and embodiment, percentage composition all refers to quality percentage composition.
embodiment 1
The refining technical process with reclaiming of acetaldehyde: with reference to process flow sheet shown in Fig. 1, vinyl acetate between to for plastic 1 reaction solution containing acetaldehyde enters dealdehyder tower A, dealdehyder tower A tower reactor vinyl acetate between to for plastic and acetic acid 2 enter vinyl acetate between to for plastic treating tower B and obtain smart vinyl acetate between to for plastic 3, vinyl acetate between to for plastic and aldehydes gas 4 that dealdehyder tower A tower top distillates enter partial condenser C, vinyl acetate between to for plastic and acetaldehyde partial condensation liquid 5 return to dealdehyder tower A, part vinyl acetate between to for plastic and acetaldehyde 6 enter acetaldehyde extraction tower D, the raffinate 8 of acetaldehyde extraction tower D returns to dealdehyder tower A, partial condenser C top enters acetaldehyde water wash column E containing the not solidifying gas 7 of acetylene and a small amount of acetaldehyde, the acetaldehyde solution 10 that is acetaldehyde solution and acetaldehyde water wash column E tower reactor containing the extraction liquid 9 of a small amount of vinyl acetate between to for plastic in acetaldehyde extraction tower D enters in acetaldehyde treating tower raw material tank F, acetaldehyde in acetaldehyde treating tower raw material tank F, vinyl acetate between to for plastic 12 enters acetaldehyde treating tower G, acetaldehyde treating tower G tower top distillates smart acetaldehyde 11, acetaldehyde treating tower G middle part extraction vinyl acetate between to for plastic and acetaldehyde mixed solution 13 return to acetaldehyde extraction tower D.
In this production process, stopper is the mixed solution of acetic acid and sodium-acetate, from acetaldehyde water wash column E be added continuously to acetaldehyde refining with recovery process process, the mass ratio of acetic acid and sodium-acetate is 0.02: 1, interpolation concentration is 750ppm, and in regulation system, the pH value of acetaldehyde solution is 4.5.
Effect: do not add before stopper, the paraldehyde quality percentage composition that acetaldehyde treating tower G distillates is 12.37%, smart acetaldehyde purity is 87.21%, and other foreign matter content is 0.420%, and other impurity comprises acetate in minute methyl esters, vinyl acetate between to for plastic, water etc.The smart vinyl acetate between to for plastic purity that vinyl acetate between to for plastic treating tower B distillates is 99.32%; Add after stopper, the paraldehyde quality percentage composition that acetaldehyde treating tower G distillates is 0.076%, smart acetaldehyde purity is 99.51%, and other foreign matter content is 0.414%.The smart vinyl acetate between to for plastic purity that vinyl acetate between to for plastic treating tower B distillates is 99.93%.
embodiment 2
With reference to technical process shown in Fig. 1, identical with embodiment 1, difference is that stopper adds (middle intermittently 3 hours) to refining and recovery system from acetaldehyde treating tower G at twice, the mass ratio of acetic acid and sodium-acetate is 0.4: 1, interpolation concentration is 2000ppm, and in regulation system, the pH value of acetaldehyde solution is 5.6.
Effect: do not add before stopper, the paraldehyde quality percentage composition that acetaldehyde treating tower G distillates is 9.77%, smart acetaldehyde purity is 90.12%, and other foreign matter content is 0.110%.The smart vinyl acetate between to for plastic purity that vinyl acetate between to for plastic treating tower B distillates is 98.84%; Add after stopper, the paraldehyde quality percentage composition that acetaldehyde treating tower G distillates is 0.075%, smart acetaldehyde purity is 99.82%, and other foreign matter content is 0.105%.The smart vinyl acetate between to for plastic purity that vinyl acetate between to for plastic treating tower B distillates is 99.95%.
embodiment 3
With reference to technical process shown in Fig. 1, identical with embodiment 1, difference is that stopper adds (middle intermittently 3 hours) to refining and recovery system from acetaldehyde treating tower raw material tank F at twice, the mass ratio of acetic acid and sodium-acetate is 0.1: 1, interpolation concentration is 25ppm, and in regulation system, the pH value of acetaldehyde solution is 4.8.
Effect: do not add before stopper, the paraldehyde quality percentage composition that acetaldehyde treating tower G distillates is 20.77%, smart acetaldehyde purity is 78.78%, and other foreign matter content is 0.450%.The smart vinyl acetate between to for plastic purity that vinyl acetate between to for plastic treating tower B distillates is 98.53%; Add after stopper, the paraldehyde quality percentage composition that acetaldehyde treating tower G distillates is 0.077%, smart acetaldehyde purity is 99.61%, and other foreign matter content is 0.313%.The smart vinyl acetate between to for plastic purity that vinyl acetate between to for plastic treating tower B distillates is 99.92%.
embodiment 4
With reference to technical process shown in Fig. 1, identical with embodiment 1, difference is that stopper joins refining and recovery system from acetaldehyde extraction tower D, and the mass ratio of acetic acid and sodium-acetate is 0.3: 1, and interpolation concentration is 1500ppm, and regulating refining system pH value is 5.2.
Effect: do not add before stopper, the paraldehyde quality percentage composition that acetaldehyde treating tower G distillates is 6.43%, smart acetaldehyde purity is 93.44%, and other foreign matter content is 0.130%.The smart vinyl acetate between to for plastic purity that vinyl acetate between to for plastic treating tower B distillates is 99.07%; Add after stopper, the paraldehyde quality percentage composition that acetaldehyde treating tower G distillates is 0.073%, smart acetaldehyde purity is 99.80%, and other foreign matter content is 0.127%.The smart vinyl acetate between to for plastic purity that vinyl acetate between to for plastic treating tower B distillates is 99.94%.
The experimental data contrast (percentage composition is quality percentage composition) as shown in table 1 of embodiment 1-4:
The effect experimental data of acetaldehyde inhibition under the processing parameter of table 1 embodiment 1-4
Claims (3)
1. the method for acetaldehyde inhibition in a polyvinyl alcohol and vinyl acetate production process, it is characterized in that, acetaldehyde refining with recovery process process in add stopper and prevent acetaldehyde autohemagglutination, and regulate acetaldehyde refining with recovery process process in the pH value of acetaldehyde solution in 4.5～5.6 scopes; Described stopper is the mixed solution of acetic acid and sodium-acetate, and wherein the mass ratio of acetic acid and sodium-acetate is 0.02～0.4: 1, and it is 25ppm～2000ppm that stopper adds concentration.
2. the method for acetaldehyde inhibition in polyvinyl alcohol according to claim 1 and vinyl acetate production process, it is characterized in that, described acetaldehyde refining with recovery process process in add stopper, concrete point of addition comprises acetaldehyde water wash column (E), acetaldehyde extraction tower (D), acetaldehyde treating tower (G) or acetaldehyde treating tower raw material tank (F).
3. the method for acetaldehyde inhibition in polyvinyl alcohol according to claim 1 and 2 and vinyl acetate production process, it is characterized in that, described acetaldehyde refining with recovery process process in add stopper, concrete mode of adding is continuous adding or portion-wise addition, and the described portion-wise addition intermittent time is 2-3 hour.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101821224A (en) * | 2007-04-05 | 2010-09-01 | 马丁家族托拉斯 | Stablize the method for aldehyde |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101821224A (en) * | 2007-04-05 | 2010-09-01 | 马丁家族托拉斯 | Stablize the method for aldehyde |
Non-Patent Citations (4)
| Title |
|---|
| 乙醛阻聚对策和罐装安全预测研究;刘瑞江等;《化工生产与技术》;20081231;第15卷(第5期);49-53 * |
| 刘瑞江等.乙醛阻聚对策和罐装安全预测研究.《化工生产与技术》.2008,第15卷(第5期),49-53. |
| 巫传英等.醋酸乙烯装置乙醛精馏塔中乙醛聚合原因分析及改造措施.《天然气化工》.2009,第34卷(第3期),63-66. |
| 醋酸乙烯装置乙醛精馏塔中乙醛聚合原因分析及改造措施;巫传英等;《天然气化工》;20091231;第34卷(第3期);63-66 * |
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