CN101306981A - Azeotropy process for catalyzing, rectifying and hydrolyzing methyl acetate - Google Patents
Azeotropy process for catalyzing, rectifying and hydrolyzing methyl acetate Download PDFInfo
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Abstract
The invention relates to an azeotropic method used in methyl acetate catalyzing rectification hydrolysis, mainly solving the problems of the prior methyl acetate catalyzing rectification hydrolysis process including complex flows and high energy consumption. The azeotropic method solves the problems better through adopting the technical proposal which comprises the following steps that: water and methyl acetate are mixed and fed in a catalyzing rectification tower from the top of the tower; the top of the tower is of total reflux and a mixture comprising methanol, acetic acid and water is obtained inside a tower bottom; the mixture is fed in a dealcoholization tower, and the distillate at the top of the dealcoholization tower is a methanol aqueous solution, while an acetic aqueous solution is obtained inside a tower bottom; the methanol aqueous solution is fed in an alcohol treating tower, and the distillate at the top of the alcohol treating tower is methanol, while waste water is generated inside a tower bottom; the acetic aqueous solution is fed in an azeotropic rectification tower which takes one sort of benzene, cyclohexane, isopropyl acetate and n-butyl acetate as an azeotropic agent; a biphase mixture of the azeotropic agent and water is obtained inside the top phase splitter of the azeotropic rectification tower with the water collected from the top of the tower and the azeotropic agent returned to the inside of the tower, while pure acetic acid is obtained inside the tower bottom of the azeotropic rectification tower. The azeotropic method can be used in the industrial production for reclaiming byproduct methyl acetate during producing polyvinyl alcohol.
Description
Technical field
The present invention relates to a kind of azeotropy process of catalyzing, rectifying and hydrolyzing methyl acetate.
Background technology
A large amount of by-product methyl acetates is arranged in the polyvinyl alcohol production process, and according to estimates, 1 ton of polyvinyl alcohol of every production is with the ritalin of 1.5～1.7 tons of by-products.Because the ritalin industrial use is little, need it is hydrolyzed into acetic acid and methyl alcohol, behind separation and purification, methyl alcohol is used for vinyl acetate between to for plastic polymerization workshop section, and it is synthetic that acetic acid is used for vinyl acetate between to for plastic.It is the fixed bed hydrolysis process of methyl acetate of catalyzer that domestic and international in the past each manufacturer all adopts with ion exchange resin.The shortcoming of this technology is per pass conversion low (percent hydrolysis can only reach 23%～24%), and a large amount of unreacted ritalins need reclaim circulation, and equipment is huge, energy consumption height, and the separation process complexity of hydrolysate.In recent years, catalytic distillation hydrolysis ritalin technical study is achieved success, and progressively is applied to suitability for industrialized production.Owing to adopted reaction rectification technique, reaction mass is separated in rectifying, and product is in time removed from reaction zone, reaction process always is under the higher ritalin concentration, thereby has improved percent hydrolysis.Industrial applications shows: the methyl acetate hydrolysis rate reaches 53%～57%, compares with the fixed bed hydrolysis process, has enlarged the processing power of equipment, has reduced catalyst consumption and has reduced energy consumption.However, still exist sepn process complexity and a large amount of unhydrolysed ritalins to need the round-robin problem.
Chinese patent literature CN1380273 has introduced present methyl acetate catalysis rectification hydrolysis technique, and the domestic full scale plant that adopts methyl acetate catalysis rectification hydrolysis technique the earliest built up and goes into operation in Fujian textile chemical fiber Group Co.,Ltd in 2000.This technology is mainly by catalytic rectifying tower, extractive distillation column, dealcoholize column, degreasing tower and azeotropy rectification column are formed, ritalin enters extractive distillation column with the ritalin that loops back from the degreasing tower, overhead distillate is a ritalin, the tower still obtains methanol aqueous solution, methanol aqueous solution enters dealcoholize column, overhead distillate is a methyl alcohol, the tower still obtains water, loop back extractive distillation column and make solvent, ritalin and water are mixed into catalytic rectifying tower, the cat head total reflux, the discharging of tower still enters the degreasing tower, and overhead distillate is ritalin and carbinol mixture, the tower still obtains aqueous acetic acid, aqueous acetic acid enters azeotropy rectification column, and overhead distillate is the water that removes, and the tower still obtains acetic acid.Because the extractive distillation column methyl acetate hydrolysis is still incomplete in the technology, follow-up flow process must be recycled by the Dichlorodiphenyl Acetate methyl esters, and ritalin, first alcohol and water form ternary azeotrope, make itself and methyl alcohol and water sepn difficulty, need to increase extractive distillation column and realize separating, so this technology exists flow process complexity, problem that energy consumption is high.
Summary of the invention
Technical problem to be solved by this invention is flow process complexity, a problem that energy consumption is high in the prior art methyl acetate catalysis rectification hydrolysis technique, a kind of azeotropy process of new catalyzing, rectifying and hydrolyzing methyl acetate is provided, and this method has that flow process is simple, characteristic of low energy consumption.
In order to solve the problems of the technologies described above, the technical solution used in the present invention is as follows: a kind of azeotropy process of catalyzing, rectifying and hydrolyzing methyl acetate, may further comprise the steps: a) mixing of water and ritalin enters catalytic rectifying tower by cat head, the cat head total reflux, and the tower still obtains the mixture of methyl alcohol, acetic acid and water; B) mixture of methyl alcohol, acetic acid and water enters dealcoholize column, and the dealcoholize column overhead distillate is a methanol aqueous solution, and the tower still obtains aqueous acetic acid; C) methanol aqueous solution enters pure treating tower, and pure treating tower overhead distillate is a methyl alcohol, and the discharging of tower still is a waste water; D) to enter with at least a in benzene, hexanaphthene, Iso Butyl Acetate or the n-butyl acetate be the azeotropy rectification column of entrainer to aqueous acetic acid, obtain the two-phase mixture of entrainer and water at its cat head phase splitter, water is from the cat head extraction, and entrainer returns in the tower, obtains pure acetic acid at the tower still.
In technique scheme, the theoretical plate number of catalytic rectifying tower is 15～50, wherein conversion zone is on tower top, and occupying the theoretical tray of whole tower 1/4～3/4, operational condition is: charging is by the cat head charging, the cat head total reflux, trim the top of column amount and charging ritalin mass ratio 2～10: 1, ritalin and quality are than 1～5: 1, and 85～95 ℃ of tower top temperatures, 90～100 ℃ of tower still temperature; The theoretical plate number of dealcoholize column is 10～50, and feed entrance point is the middle and lower part of tower, and reflux ratio is 1～10, and tower top temperature is 64.7～95 ℃, and tower still temperature is 100～118 ℃; Pure and mild acid in the dealcoholize column separates fully, and the mass percentage concentration of tower still acetic acid is greater than 50%; The theoretical plate number of alcohol treating tower is 10～40, and feed entrance point is the middle and lower part of tower, and reflux ratio is 2～7, and tower top temperature is 64.7～65.8 ℃, and tower still temperature is 99～105 ℃; The theoretical plate number of azeotropy rectification column is 10～50, and the aqueous acetic acid feed entrance point is the middle and lower part of tower, and reflux ratio is 0.5～4, and tower top temperature is 64～100 ℃, and tower still temperature is 115～118 ℃.
Because ritalin of the present invention complete hydrolysis in catalytic rectifying tower, the problem that does not exist ritalin to reclaim, and employing azeotropic distillation separating acetic acid and water, therefore make that technical process of the present invention is short, under suitable operational condition, its cat head can the former technology of loss-rate reduce 15%, and tower still energy consumption reduces 20%.
Description of drawings
Fig. 1 is the azeotropic process flow diagram of catalyzing, rectifying and hydrolyzing methyl acetate.
1 is catalytic rectifying tower among Fig. 1, and 2 is dealcoholize column, and 3 is pure treating tower, 4 is azeotropy rectification column, and 5 is mixing tank, and 6 is water, 7 is ritalin, and 8 is the ritalin aqueous solution, and 9 is the aqueous solution of methyl alcohol, acetic acid, 10 is methanol aqueous solution, 11 is aqueous acetic acid, and 12 is methyl alcohol, and 13 is waste water, 14 is water, and 15 is acetic acid.
The present invention is further illustrated below by specific embodiment, and still, scope of the present invention has more than and is limited to the scope that embodiment covers.
Embodiment
[embodiment 1]
By flow process shown in Figure 1: the number of theoretical plate of catalytic rectifying tower is 15, wherein the 10 theoretical stage loading catalysts in tower top.Ritalin and water are respectively with 1 kilogram/hour, 1.4 kilogram/hour flow enters catalytic rectifying tower, the trim the top of column amount is 8 kilograms/hour, the control tower top temperature is 87～92 ℃, and it is 50 dealcoholize column that the discharging of tower still enters number of theoretical plate, and feed entrance point is the 30th theoretical stage, reflux ratio is 2, tower top temperature is 80～85 ℃, and overhead distillate is a methanol aqueous solution, and the discharging of tower still is an aqueous acetic acid, methanol aqueous solution enters pure treating tower, number of theoretical plate is 15, and feed entrance point is the 10th a block of column plate, and reflux ratio is 6, the control tower top temperature is 64.7～65.8 ℃, overhead distillate is a methyl alcohol, and the tower still obtains waste water, and aqueous acetic acid enters azeotropy rectification column, entrainer is an Iso Butyl Acetate, entrainer is 1.5 with the raw materials quality ratio, and number of theoretical plate is 15, and the raw material feed entrance point is the 10th theoretical stage, entrainer is disposable to add from cat head, reflux ratio is 4, and control tower still temperature is 115～118 ℃, and the cat head extraction is a water, the tower still obtains acetic acid, and the analytical results of each logistics and the energy consumption of Ge Ta see Table 1 and table 2 respectively.
The analytical results of each logistics of table 1 (quality %)
The energy consumption of each tower of table 2 (million Jiao/hour)
[embodiment 2]
The number of theoretical plate of catalytic rectifying tower is 45, wherein the 12 theoretical stage loading catalysts in tower top.Ritalin and water enter catalytic rectifying tower with 1 kilogram/hour, 1.2 kilograms/hour flow respectively, the trim the top of column amount is 2 kilograms/hour, the control tower top temperature is 87～92 ℃, the equipment of other each tower and operating parameters such as embodiment 1, the analytical results of each logistics and the energy consumption of Ge Ta see Table 3 and table 4 respectively.
The analytical results of each logistics of table 3 (quality %)
The energy consumption of each tower of table 4 (million Jiao/hour)
[embodiment 3]
Only change the condition of dealcoholize column, other each condition such as embodiment 1.The number of theoretical plate of dealcoholize column is 10, and feed entrance point is the 6th a block of theoretical tray, and reflux ratio is 8, and the control tower top temperature is 80～85 ℃, and after the stable operation, the analytical results of each logistics and the energy consumption of Ge Ta see Table 5 and table 6 respectively.
The analytical results of each logistics of table 5 (quality %)
The energy consumption of each tower of table 6 (million Jiao/hour)
[embodiment 4]
Only change the condition of azeotropy rectification column, other each condition such as embodiment 1.The entrainer of azeotropy rectification column changes n-butyl acetate into, and number of theoretical plate still is 45, and the principle feed entrance point is the 30th a block of column plate, and reflux ratio is 1, and control tower still temperature is 115～118 ℃, and the analytical results of each logistics and the energy consumption of Ge Ta see Table 7 and table 8 respectively.
The analytical results of each logistics of table 7 (quality %)
The energy consumption of each tower of table 8 (million Jiao/hour)
[comparative example 1]
Adopt the technical process among the patent CN1380273, wherein the number of theoretical plate of catalytic rectifying tower is 15, wherein the 8 theoretical stage loading catalysts in tower top.Ritalin and water are respectively with 1 kilogram/hour, 0.4 kilogram/hour flow enters catalytic rectifying tower, the trim the top of column amount is 3 kilograms/hour, it is 20 degreasing tower that the discharging of tower still enters number of theoretical plate, feed entrance point is the 15th theoretical stage, reflux ratio is 3, overhead distillate mixes back extractive distillation column, the number of theoretical plate of extractive distillation column is 20, the solvent feed position is the 3rd a block of column plate, and the raw material charging is the 12nd a block of column plate, and reflux ratio is 2, the overhead distillate ritalin enters catalytic rectifying tower, the discharging of tower still enters dealcoholize column, and the dealcoholize column cat head obtains pure methyl alcohol, and the tower still is a waste water, the tower still discharging of degreasing tower enters azeotropy rectification column, the number of theoretical plate of azeotropy rectification column is 20, and feed entrance point is the 13rd a block of column plate, and entrainer is an Iso Butyl Acetate, cat head phase splitter oil phase returns in the tower, water discharging, tower still obtain acetic acid (moisture mass percent 0.02%), and the energy consumption data of each tower sees Table 9.
The energy consumption of each tower of table 9 (million Jiao/hour)
Claims (6)
1, a kind of azeotropy process of catalyzing, rectifying and hydrolyzing methyl acetate may further comprise the steps:
A) mixing of water and ritalin enters catalytic rectifying tower by cat head, the cat head total reflux, and the tower still obtains the mixture of methyl alcohol, acetic acid and water;
B) mixture of methyl alcohol, acetic acid and water enters dealcoholize column, and the dealcoholize column overhead distillate is a methanol aqueous solution, and the tower still obtains aqueous acetic acid;
C) methanol aqueous solution enters pure treating tower, and pure treating tower overhead distillate is a methyl alcohol, and the discharging of tower still is a waste water;
D) to enter with at least a in benzene, hexanaphthene, Iso Butyl Acetate or the n-butyl acetate be the azeotropy rectification column of entrainer to aqueous acetic acid, obtain the two-phase mixture of entrainer and water at its cat head phase splitter, water is from the cat head extraction, and entrainer returns in the tower, obtains pure acetic acid at the tower still.
2, according to the azeotropy process of right 1 described catalyzing, rectifying and hydrolyzing methyl acetate, the theoretical plate number that it is characterized in that catalytic rectifying tower is 15～50, wherein conversion zone is on tower top, and occupying the theoretical tray of whole tower 1/4～3/4, operational condition is: charging is by the cat head charging, the cat head total reflux, trim the top of column amount and charging ritalin mass ratio 2～10: 1, ritalin and quality are than 1～5: 1, and 85～95 ℃ of tower top temperatures, 90～100 ℃ of tower still temperature.
3, according to the azeotropy process of right 1 described catalyzing, rectifying and hydrolyzing methyl acetate, the theoretical plate number that it is characterized in that dealcoholize column is 10～50, and feed entrance point is the middle and lower part of tower, and reflux ratio is 1～10, tower top temperature is 64.7～95 ℃, and tower still temperature is 100～118 ℃.
4, according to the azeotropy process of right 1 described catalyzing, rectifying and hydrolyzing methyl acetate, it is characterized in that the pure and mild acid in the dealcoholize column separates fully, the mass percentage concentration of tower still acetic acid is greater than 50%.
5, according to the azeotropy process of right 1 described catalyzing, rectifying and hydrolyzing methyl acetate, the theoretical plate number that it is characterized in that pure treating tower is 10～40, and feed entrance point is the middle and lower part of tower, and reflux ratio is 2～7, tower top temperature is 64.7～65.8 ℃, and tower still temperature is 99～105 ℃.
6, according to the azeotropy process of right 1 described catalyzing, rectifying and hydrolyzing methyl acetate, the theoretical plate number that it is characterized in that azeotropy rectification column is 10～50, and the aqueous acetic acid feed entrance point is the middle and lower part of tower, and reflux ratio is 0.5～4, tower top temperature is 64～100 ℃, and tower still temperature is 115～118 ℃.
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102179059A (en) * | 2011-02-24 | 2011-09-14 | 中国石油大学(华东) | Hydrolysis separation device of methyl acetate and process method thereof |
| CN102775272A (en) * | 2012-08-14 | 2012-11-14 | 北京旭阳化工技术研究院有限公司 | Preparation method of succinic acid |
| WO2012164573A2 (en) | 2011-05-27 | 2012-12-06 | Reliance Industries Ltd., | Hydrolysis and esterification with acid catalysts |
| CN102875353A (en) * | 2012-10-16 | 2013-01-16 | 江苏沿江化工资源开发研究院有限公司 | Method for extracting acetic acid from carbon-soot-containing acetic acid water solution through dust removal/side-stream discharge/azeotropic rectification |
| CN102992993A (en) * | 2011-09-17 | 2013-03-27 | 天华化工机械及自动化研究设计院有限公司 | Acetic acid+water azeotropic-rectification energy-saving consumption-reduction method by adding heat pump |
| CN109467499A (en) * | 2018-08-03 | 2019-03-15 | 天津大学 | The anticorrosion process and device of methyl acetate hydrolysis and acetic acid refining during polyvinyl alcohol disposing mother liquor |
| CN109467497A (en) * | 2018-08-03 | 2019-03-15 | 内蒙古蒙维科技有限公司 | A kind of recovery process and device of polyvinyl alcohol alcohol hydrolysis mother liquor |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1057079C (en) * | 1996-02-09 | 2000-10-04 | 福州大学 | Catalystic rectification and hydrolization technology and equipment for methyl acetate |
| CN100418939C (en) * | 2006-09-15 | 2008-09-17 | 福州大学 | Hydrolysis process of methyl acetate as by-product of producing refined terephthalic acid and apparatus thereof |
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- 2007-05-16 CN CN2007100407041A patent/CN101306981B/en active Active
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| CN102179059A (en) * | 2011-02-24 | 2011-09-14 | 中国石油大学(华东) | Hydrolysis separation device of methyl acetate and process method thereof |
| WO2012164573A2 (en) | 2011-05-27 | 2012-12-06 | Reliance Industries Ltd., | Hydrolysis and esterification with acid catalysts |
| CN102992993A (en) * | 2011-09-17 | 2013-03-27 | 天华化工机械及自动化研究设计院有限公司 | Acetic acid+water azeotropic-rectification energy-saving consumption-reduction method by adding heat pump |
| CN102992993B (en) * | 2011-09-17 | 2014-08-27 | 天华化工机械及自动化研究设计院有限公司 | Acetic acid+water azeotropic-rectification energy-saving consumption-reduction method by adding heat pump |
| CN102775272A (en) * | 2012-08-14 | 2012-11-14 | 北京旭阳化工技术研究院有限公司 | Preparation method of succinic acid |
| CN102875353A (en) * | 2012-10-16 | 2013-01-16 | 江苏沿江化工资源开发研究院有限公司 | Method for extracting acetic acid from carbon-soot-containing acetic acid water solution through dust removal/side-stream discharge/azeotropic rectification |
| CN102875353B (en) * | 2012-10-16 | 2014-11-26 | 江苏沿江化工资源开发研究院有限公司 | Method for extracting acetic acid from carbon-soot-containing acetic acid water solution through dust removal/side-stream discharge/azeotropic rectification |
| CN109467499A (en) * | 2018-08-03 | 2019-03-15 | 天津大学 | The anticorrosion process and device of methyl acetate hydrolysis and acetic acid refining during polyvinyl alcohol disposing mother liquor |
| CN109467497A (en) * | 2018-08-03 | 2019-03-15 | 内蒙古蒙维科技有限公司 | A kind of recovery process and device of polyvinyl alcohol alcohol hydrolysis mother liquor |
| CN109467497B (en) * | 2018-08-03 | 2023-11-10 | 内蒙古蒙维科技有限公司 | Recovery process and device for polyvinyl alcohol alcoholysis mother liquor |
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