CN100531845C - Salt-adding intermittent extraction, rectified separation method of acetonitrile-water azeotropic mixture - Google Patents
Salt-adding intermittent extraction, rectified separation method of acetonitrile-water azeotropic mixture Download PDFInfo
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- CN100531845C CN100531845C CNB2007101507418A CN200710150741A CN100531845C CN 100531845 C CN100531845 C CN 100531845C CN B2007101507418 A CNB2007101507418 A CN B2007101507418A CN 200710150741 A CN200710150741 A CN 200710150741A CN 100531845 C CN100531845 C CN 100531845C
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Abstract
The invention provides a method of batch extractive distillation with salt for separating an acetonitrile-water azeotropic mixture. The method adopts the rectification column of an extractive distillation column, the rectification column has batch operation, glycol solution which contains calcium chloride is taken as extraction solvent, under the normal pressure, the infinite branch reflux operation is firstly carried out, then acetonitrile products, acetonitrile-water transition section fraction and dehydration are orderly withdrawn from the extractive distillation column under the operation conditions of different temperatures and reflux ratios, and then water-glycol transition section fraction is withdrawn under the decompression condition, finally, the glycol extraction solvent which contains the calcium chloride and is stored in a heating pot is pumped into an extraction solvent storage tank, and a new batch acetonitrile-water mixture as well as the acetonitrile-water transition section fraction and the water-glycol transition section fraction are loaded into the heating pot for carrying out the next batch extractive distillation and separation. The method has the advantages that the adopted extraction solvent destroys the acetonitrile-water azeotropic system, the acetonitrile products with high purity can be separated out, the single-tower operation is adopted, the operation is flexible, and the expenditure and the investment of the equipment are less.
Description
Technical field
The present invention relates to a kind of adding salt intermittent extraction rectification separation method of acetonitrile-water azeotropic mixture, belong to the isolation technics of acetonitrile-water azeotropic mixture.
Background technology
Extractive distillation with salt is a kind of extraordinary rectifying isolation technics, salt is dissolved in solvent form mixed extractant, is fit to the separation of azeotropic system.Add this mixed extractant continuously by top and reach the separation purpose with the relative volatility that changes between stock blend toward rectifying column.Extractive distillation with salt has merged the advantage of dissolved salt rectifying and extracting rectifying, it utilizes salting out, improved the solvent effect, reduced ratio of solvent, can also keep extractant circulation and recovery easily, be convenient in industrial realization, have unique advantage and usefulness, be suitable for separating of the azeotropic system and the system of closely boiling.Acetonitrile is a kind of important chemical material and organic solvent, in the solvent recovery process of medical industry, be easy to generate acetonitrile-aqueous mixtures, owing to forming azeotropic mixture, acetonitrile-water is difficult to separate, as not reclaiming, not only pollute the environment, and increase production cost, the separation method of therefore developing acetonitrile-water azeotropic mixture has important meaning.About the article and the patent of separating this mixture more, the data of the acetonitrile that Shang Weijian publishes-water azeotropic system extractive distillation with salt separation aspect.
Summary of the invention
The object of the present invention is to provide a kind of adding salt intermittent extraction rectification separation method of acetonitrile-water azeotropic mixture.With the isolated acetonitrile product purity of this method height, and equipment investment is few.
The present invention is realized by following technical proposals.A kind of adding salt intermittent extraction rectification separation method of acetonitrile-water azeotropic mixture, this method adopts and comprises extractive distillation column, heating kettle at the bottom of the extracting rectifying Tata, the extracting rectifying column overhead connects the rectifier unit of condenser and high-order storage tank and receiving tank, intermittently operated separating acetonitrile-water azeotropic mixture, it is characterized in that comprising following process: the employing mass content is that the ethylene glycol solution of 5-20% calcium chloride is an extractant, extractive distillation column is operated with following condition: under normal pressure, the extractant that the rising steam that still to be heated produces rises to extractive distillation column adds when entering the mouth, be that 25-80 ℃ extractant is introduced extractive distillation column top from the extractant storage tank and carried out total reflux operation with temperature, entering the extractant of extractive distillation column and the volume ratio of extracting rectifying cat head liquid capacity of returns is 0.5:1-5:1; When extracting rectifying cat head temperature is 81-83 ℃, reach 99% product to acetonitrile product jar by extracting rectifying cat head extraction acetonitrile mass content with reflux ratio 1:1-5:1; When extracting rectifying cat head temperature is lower than 81 ℃, stop to add extractant, by extracting rectifying cat head extraction acetonitrile-water changeover portion cut, tower top temperature drops to 77 ℃ earlier in this process with reflux ratio 2:1-10:1, then rises to 99 ℃; When extracting rectifying cat head temperature is 100-101 ℃, with reflux ratio 1:1-4:1 dehydration; When extracting rectifying cat head temperature surpasses 101 ℃, and with extracting rectifying tower top pressure 50KPa operation, with reflux ratio 4:1-8:1, by extracting rectifying cat head recovered water-ethylene glycol changeover portion cut; The water quality content of extractant is less than 0.1% in heating kettle, stop and cool off, extractant is squeezed into the extractant storage tank with pump, heating kettle pack into new a collection of acetonitrile-aqueous mixtures and acetonitrile-water changeover portion cut and water-ethylene glycol changeover portion cut, following batch of batch extracting rectified separation.
The invention has the advantages that and adopt extractant to destroy acetonitrile-water azeotropic system, isolate the high-purity acetonitrile product, adopt single tower operation, flexible operation, cost of equipment less investment.
Description of drawings
Fig. 1 is apparatus of the present invention and schematic flow sheet.
Among the figure: 1-extractant storage tank, 2-extractive distillation column, 3-heating kettle, 4-condenser, 5-acetonitrile product jar, 6-acetonitrile-water changeover portion cut receiving tank, 7-dehydration receiving tank, 8-water-ethylene glycol changeover portion cut receiving tank.
The specific embodiment
The idiographic flow of Fig. 1: acetonitrile-aqueous mixtures adds in the heating kettle 3, open the thermal source of heating kettle and the low-temperature receiver of condenser 4, treat that the interior rising steam of extractive distillation column rises to extractant and adds when entering the mouth, extractant is introduced into batch extracting rectified tower top from extractant storage tank 1, infinite reflux a period of time, when the acetonitrile mass content reaches 99% discharging when requiring, enter acetonitrile product jar 5, when ethane nitrile content is lower than product requirement in the extracting rectifying overhead fraction, the cut of extracting rectifying cat head extraction enters that acetonitrile-water changeover portion cut receiving tank 6 (at this moment, stop to add extractant), when water quality content reaches 99% in the extracting rectifying overhead fraction, the material of extraction enters dehydration receiving tank 7, water quality content is lower than 98% in the extracting rectifying overhead fraction, the cut of extraction enters water-ethylene glycol changeover portion cut receiving tank 8, when the water quality content of heating kettle extractant less than 0.1% the time, stop.Heating kettle is the mixed extractant of high concentration, squeezes into the extractant storage tank and recycles.The material of two changeover portions is put in the heating kettle when next group distills.
Embodiment one
Adopt batch extraction rectification device, wherein the extractive distillation column diameter is φ 40mm, interior dress Dixon ring filler, and bed stuffing height is 1.15m, the extractant import is at distance cat head 0.15m place.(wherein acetonitrile 80% to drop into 500ml acetonitrile-aqueous mixtures at heating kettle, water 20%, be mass percent), test the ethylene glycol solution that selected mixed extractant is a calcium chloride (containing calcium chloride 10%), open heating kettle thermal source and condenser low-temperature receiver, then extractive distillation column brings into operation, treat that the interior rising steam of extractive distillation column rises to extractant and adds when entering the mouth, extractant is added in the extractive distillation column by the extractant import, and the control extractant adds speed 600ml/h, total reflux operation, when extracting rectifying cat head temperature is 81.5-82 ℃, ethane nitrile content in the cut 〉=99% beginning discharging, reflux ratio is 2:1, discharging speed is 200ml/h.When extracting rectifying cat head temperature during less than 81 ℃, stop to add extractant, with the reflux ratio 8:1 extraction acetonitrile-water changeover portion, extracting rectifying cat head temperature drops to 77 ℃ earlier in this process, then rise to 99 ℃,, dewater with reflux ratio 2:1 when extracting rectifying cat head temperature is 100-101 ℃, when extracting rectifying cat head temperature is higher than 101 ℃, adopt the 50kPa operation, reflux ratio is 4:1, recovered water-ethylene glycol changeover portion, the water quality content of heating kettle extractant stopped less than 0.1% o'clock.
Claims (1)
1. the adding salt intermittent extraction rectification separation method of an acetonitrile-water azeotropic mixture, this method adopts and comprises extractive distillation column, heating kettle at the bottom of the extracting rectifying Tata, the extracting rectifying column overhead connects the rectifier unit of condenser and high-order storage tank and receiving tank, intermittently operated separating acetonitrile-water azeotropic mixture, it is characterized in that comprising following process: the employing mass content is that the ethylene glycol solution of 5-20% calcium chloride is an extractant, extractive distillation column is operated with following condition: under normal pressure, the extractant that the rising steam that still to be heated produces rises to extractive distillation column adds when entering the mouth, be that 25-80 ℃ extractant is introduced extractive distillation column top from the extractant storage tank and carried out total reflux operation with temperature, entering the extractant of extractive distillation column and the volume ratio of extracting rectifying cat head liquid capacity of returns is 0.5:1-5:1; When extracting rectifying cat head temperature is 81-83 ℃, reach 99% product to acetonitrile product jar by extracting rectifying cat head extraction acetonitrile mass content with reflux ratio 1:1-5:1; When extracting rectifying cat head temperature is lower than 81 ℃, stop to add extractant, by extracting rectifying cat head extraction acetonitrile-water changeover portion cut, tower top temperature drops to 77 ℃ earlier in this process with reflux ratio 2:1-10:1, then rises to 99 ℃; When extracting rectifying cat head temperature is 100-101 ℃, with reflux ratio 1:1-4:1 dehydration; When extracting rectifying cat head temperature surpasses 101 ℃, and with extracting rectifying tower top pressure 50KPa operation, with reflux ratio 4:1-8:1, by extracting rectifying cat head recovered water-ethylene glycol changeover portion cut; The water quality content of extractant is less than 0.1% in heating kettle, stop and cool off, extractant is squeezed into the extractant storage tank with pump, heating kettle pack into new a collection of acetonitrile-aqueous mixtures and acetonitrile-water changeover portion cut and water-ethylene glycol changeover portion cut, following batch of batch extracting rectified separation.
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| Application Number | Priority Date | Filing Date | Title |
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| CNB2007101507418A CN100531845C (en) | 2007-12-05 | 2007-12-05 | Salt-adding intermittent extraction, rectified separation method of acetonitrile-water azeotropic mixture |
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| CNB2007101507418A CN100531845C (en) | 2007-12-05 | 2007-12-05 | Salt-adding intermittent extraction, rectified separation method of acetonitrile-water azeotropic mixture |
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| CN100531845C true CN100531845C (en) | 2009-08-26 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102527072B (en) * | 2012-03-23 | 2014-08-13 | 济南大学 | Batch extraction distillation separation method for propyl alcohol-propyl formate azeotropic mixture |
| CN103601618A (en) * | 2013-11-22 | 2014-02-26 | 天津大学 | Method for extracting, rectifying and separating alcohol-water azeotropic mixture |
| CN103641700A (en) * | 2013-11-22 | 2014-03-19 | 天津大学 | Method for separating butanone-water azeotrope through extraction distillation |
| CN103601653A (en) * | 2013-11-22 | 2014-02-26 | 天津大学 | Method for extracting, rectifying and separating acetonitrile-water azeotropic mixture |
| CN103588620A (en) * | 2013-11-22 | 2014-02-19 | 天津大学 | Method for separating isopropyl alcohol-water azeotropic mixture through extractive distillation |
| CN104961651A (en) * | 2015-05-18 | 2015-10-07 | 中国石油大学(华东) | Method for separation of acetonitrile and water by use of extraction rectification dividing wall column |
| CN107400064A (en) * | 2016-05-18 | 2017-11-28 | 辽宁石油化工大学 | A kind of divided wall extractive distillation column refines the method containing water-acetonitrile |
| CN108623440B (en) * | 2017-03-16 | 2020-05-12 | 中昊晨光化工研究院有限公司 | Separation and purification method of 1,1,2, 2-tetrafluoroethyl-2 ', 2', 3 ', 3' -tetrafluoropropyl ether |
| CN109231635B (en) * | 2018-11-20 | 2023-05-09 | 江苏九天高科技股份有限公司 | Wastewater treatment process |
| CN118359517B (en) * | 2024-04-19 | 2024-09-24 | 扬州贝尔新环境科技有限公司 | Production process of anhydrous acetonitrile |
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