CN110156590A - A method of spirit of vinegar is recycled based on extraction/azeotropic distillation coupling technique - Google Patents
A method of spirit of vinegar is recycled based on extraction/azeotropic distillation coupling technique Download PDFInfo
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- CN110156590A CN110156590A CN201910455822.1A CN201910455822A CN110156590A CN 110156590 A CN110156590 A CN 110156590A CN 201910455822 A CN201910455822 A CN 201910455822A CN 110156590 A CN110156590 A CN 110156590A
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/42—Separation; Purification; Stabilisation; Use of additives
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/42—Separation; Purification; Stabilisation; Use of additives
- C07C51/43—Separation; Purification; Stabilisation; Use of additives by change of the physical state, e.g. crystallisation
- C07C51/44—Separation; Purification; Stabilisation; Use of additives by change of the physical state, e.g. crystallisation by distillation
- C07C51/46—Separation; Purification; Stabilisation; Use of additives by change of the physical state, e.g. crystallisation by distillation by azeotropic distillation
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/42—Separation; Purification; Stabilisation; Use of additives
- C07C51/48—Separation; Purification; Stabilisation; Use of additives by liquid-liquid treatment
Abstract
Use isopropyl acetate and isopropanol mixture as the process flow of the extraction of solvent-azeotropic distillation coupling recycling spirit of vinegar the present invention relates to a kind of.Isopropyl acetate and isopropanol function simultaneously as the entrainer in extractant and azeotropy rectification column in extraction tower in this method.It allows low-concentration acetic acid wastewater and solvent to carry out counter current contacting in extraction tower first, liquid-liquid extraction occurs.Extraction phase rich in acetic acid is sent to azeotropy rectification column, obtains the acetate products of high-purity in azeotropy rectification column tower bottom.Raffinate phase rich in water is admitted to solvent recovery tower recovered overhead solvent.The product of azeotropy rectification column and solvent recovery top of tower is sent into phase-splitter and carries out Phase separation, and organic phase is sent extraction tower bottom back to and recycled, and water phase is sent into solvent recovery tower.The present invention carries out pre- concentrate operation using liquid-liquid extraction method, greatly reduces energy consumption, while using isopropyl acetate and isopropyl alcohol mixed solvent, reduces solvent internal circulating load, it is possible to reduce equipment investment further decreases energy consumption.The present invention has the characteristics that separative efficiency is high, the rate of recovery is high.
Description
Technical field
The present invention relates to a kind of based on extraction/azeotropic distillation coupling technique recycling spirit of vinegar method, belongs to chemical separating
Process, the recycling of acetic acid suitable for low-concentration acetic acid wastewater.
Background technique
Acetic acid is one of most common organic acid, and the purposes in industrial processes is very extensive, may be used as solvent
Or reactant.For example in the production process that p xylene oxidation generates terephthalic acid (TPA), it serves as the solvent of reaction.While it
It is also acetic anhydride, the important source material in the organic syntheses industry such as aspirin.In the use process of acetic acid, it will usually generate dilute
Acetic acid wastewater, and the content of acetic acid will be lower than 2%(mass percent in " national discharge standard " regulation discharge of wastewater), because
Acetic acid is that many chemical separation processes need problems faced in this recovery of acetic acid waste water.The recycling of acetic acid is for green
Color chemical industry plays the role of particularly important.
Currently, mainly including conventional distillation method, azeotropic distillation, esterification process and liquid liquid for separating acetic acid and the method for water
Extraction etc..Conventional distillation method needs many numbers of plates, and it is very uneconomical that higher reflux ratio, which can generate a large amount of energy consumption,
Separation method.Azeotropic distillation can reduce reflux ratio due to joined entrainer, the number of plates needed for reducing, to high concentration
Acetic acid wastewater recycling is very economical environmental protection.However when acetic acid content is lower in acetic acid wastewater, need to increase the amount of entrainer,
Increase the energy consumption of system.
Chinese patent CN102267889 reports a kind of process flow of extraction-azeotropic distillation coupling, the solvent agent of selection
Such as n-butyl acetate, isobutyl acetate, isopropyl acetate and n-propyl acetate and its mixture are added from extraction tower bottom, but
It is that entire process flow is more complicated, and feeds and need to be separately added into from extraction tower and azeotropy rectification column.
Summary of the invention
In order to solve the deficiencies in the prior art, set forth herein a kind of extraction-azeotropic distillation coupling process flows, and adopt
Use isopropyl acetate and isopropanol as mixed solvent.
The method of the present invention includes following processes:
(1) extraction process
In liquid-liquid extraction tower, dilute acetic acid solution is added from the top of tower, and extractant is added from the bottom of tower, selected extractant
For the mixture of isopropyl acetate and isopropanol, two-phase counter current contacting in extraction tower.What extraction column overhead obtained is containing big
The extraction phase of partial extraction agent, acetic acid and a small amount of water, extraction tower tower bottom are obtained containing a large amount of water, a small amount of extractant and a small amount of
The extraction phase of acetic acid.Extraction phase is sent into azeotropy rectification column, and extraction phase is sent into solvent recovery tower.
(2) azeotropy rectification column and solvent recovery tower distillation process
Extraction phase in process (1) is injected into azeotropy rectification column, azeotropy rectification column tower bottom obtains the acetic acid product of high-purity, tower top
Obtain water and solvent.Overhead product forms water phase (comprising most of water) and organic phase (comprising most of molten after split-phase
Agent).Water phase is passed through solvent recovery tower recovered overhead solvent, organic phase together with the raffinate phase of the extraction tower tower bottom in process (1)
Then it is recycled back to the tower bottom of extraction tower.Supplementing solvent is added in phase-splitter.
This kind of extraction-azeotropic coupling technique is relatively specific for acetic acid waste liquid of the acetic acid quality fraction range between 10-40%
Dehydration.
The operating condition of extraction tower are as follows: operate under normal pressure；Operation temperature is between 10-50 DEG C；Packed tower is selected, is filled out
Material height is equivalent to 20 ~ 30 pieces of theoretical plates；Spirit of vinegar and solvent quality ratio are 1: 1.5 ~ 1: 3.5.
The operating condition of azeotropy rectification column are as follows: operate under normal pressure；Number of theoretical plate is at 25 ~ 35 pieces；Extract the extraction of tower top
Mutually enter height of the position in 12 ~ 17 pieces of theoretical plates of azeotropy rectification column.
The operating condition of solvent recovery tower are as follows: operate under normal pressure；Number of theoretical plate is at 6 ~ 12 pieces；The extraction phase at extraction tower bottom
It is fed with the water phase in phase-splitter in tower top.
The solvent isopropanol of selection and the mass ratio of isopropyl acetate are 1: 5 ~ 1: 20.The recovery rate of the extraction tower
>=96%, mass fraction >=96% of the acetic acid of azeotropy rectification column tower bottom.
Advantages of the present invention: herein using extraction-azeotropic distillation coupling process flow, vinegar lower for acetic acid content
Sour wastewater treatment has preferably economic benefit.On the one hand, liquid-liquid extraction energy consumption is low, can be the case where not consuming big energy
Under have the effect of pre- concentrate for the spirit of vinegar in charging；On the other hand, the solvent used be isopropyl acetate and isopropanol, both
Extractant is served as, entrainer is also functioned as.Compared with the one-component extractant used in the prior art, identical recycling is completed
Under rate requires, it is possible to reduce the solvent internal circulating load in process flow further reduces the energy consumption of azeotropy rectification column in process, also
Equipment size can be reduced, more significant economic benefit is brought.
Detailed description of the invention
Fig. 1 is extraction-azeotropic distillation coupling process flow chart of acetic acid dehydration
T1 is extraction tower in Fig. 1, and T2 is azeotropy rectification column, and T3 is solvent recovery tower, and 1 is dilute acetic acid solution, and 2 be extraction phase, and 3 are
Raffinate phase, 4 be azeotropy rectification column overhead product, and 5 be high-purity acetic acid, and 6 be solvent recovery tower overhead, and 7 be supplementing solvent,
8 be organic phase, that is, the extractant recycled, and 9 be water phase, and 10 be waste water.
Spirit of vinegar 1 and extractant 8 enter from T1 tower top and tower bottom respectively, after extraction and separation, extraction phase 2 and raffinate phase
3 produce from tower top and tower bottom respectively.Logistics 2 enters azeotropy rectification column T2, and logistics 3 enters solvent recovery tower T3 tower top.The tower of T2
The product 6 of top product 4 and T3 tower top condenses through condenser after mixing and is sent into phase-splitter split-phase, wherein organic phase logistics (extraction
Agent 8) it is sent into T1 bottom cycle, water phase logistics 9 is sent at the top of T3.T2 and T3 tower bottom respectively obtains high-purity acetic acid stream 5 and gives up
Water logistics 10, supplementing solvent logistics 7 are added at the top of phase-splitter.
Specific embodiment
Embodiment 1
The specific flow chart of embodiment is referring to Fig. 1.The material of the present embodiment forms based on mass fraction.
The flow of logistics 1 is 5000 kg/h, and the mass fraction of acetic acid is 30%, and the mass fraction of water is 70%, feeding temperature
It is 40 DEG C, from extraction tower T1 top-feed.Extraction tower T1 selects packed tower, and tower diameter is 0.8 m, operation temperature 40
DEG C, it operates under normal pressure, number of theoretical plate is 26 pieces.8 flow of logistics is 5403 kg/h, wherein the mass fraction of isopropyl acetate
It is 76.9%, the mass fraction of isopropanol is 19.2%, and the mass fraction of water is 3.9%.2 feed entrance point of logistics is the 14th piece of theory
Plate, flow are 6724 kg/h, and wherein the mass fraction of water is 10%, and the mass fraction of acetic acid is 22%, the quality of isopropyl acetate
Score is 61%, and the mass fraction of isopropanol is 7%.The mass flow of logistics 3 is 3680 kg/h, and wherein the mass fraction of water is
83%, the mass fraction of isopropyl acetate is 3%, and the mass fraction of isopropanol is 14%, the mass fraction < 0.05% of acetic acid.Azeotropic
The operating condition of rectifying column T2 are as follows: atmospheric operation, tower top temperature are 74 DEG C, and column bottom temperature is that 118 DEG C of number of theoretical plates are 26 pieces,
Tower diameter is 1.2 m, and overhead reflux ratio is 0.666.The mass flow of logistics 5 is 1503 kg/h, and the mass fraction of acetic acid is
99.7%.The flow of logistics 4 is 5220 kg/h, and wherein the mass fraction of water is 13%, and the mass fraction of isopropyl acetate is 79%,
The mass fraction of isopropanol is 8%.The operating condition of solvent recovery tower: atmospheric operation, number of theoretical plate are 9 pieces, and tower diameter is 0.6 m,
Tower top temperature is 75 DEG C, and column bottom temperature is 100 DEG C.
The flow of logistics 10 is 3500 kg/h, and the mass fraction of water is 99.5%.The logistics 6 that tower top obtains, mass flow
For 1077 kg/h, wherein the mass fraction of water is 26%, and the mass fraction of isopropanol is 14%, the mass fraction of isopropyl acetate
It is 60%.The mass flow of logistics 9 is 897 kg/h, and wherein the mass fraction of water is 82%, and the mass fraction of isopropyl acetate is
3%, the mass fraction of isopropanol is 15%, and the rate of recovery of entire process flow acetic acid reaches 99%.
Embodiment 2
Keep the operating condition such as embodiment 1 of extraction tower T1 and solvent recovery tower T3 constant, the reflux ratio of azeotropy rectification column T2 is
1.4, other operating conditions are constant, change the ratio of isopropyl acetate and isopropanol in extractant, the quality point of isopropyl acetate
Number is 95%, and the mass fraction of isopropanol is 5%.The rate of recovery of acetic acid is 97% after entire process flow separation.Acetate products
The mass flow of logistics 5 is 1461.26 kg/h, and the mass fraction of acetic acid is 99.8%.The mass flow of waste water streams 10 is
3539 kg/h, the mass fraction of water are 99%.
Claims (3)
1. a kind of based on extraction-azeotropic distillation coupling technique recycling spirit of vinegar method, it is characterised in that: this method is using extraction
Take-azeotropic distillation coupling technique, wherein include extraction tower, azeotropy rectification column, solvent recovery tower, phase-splitter, with isopropyl acetate/
Isopropanol binary mixture is extractant and entrainer, and the following steps are included: (1) allows low-concentration acetic acid wastewater and extractant to exist
Counter current contacting is carried out in extraction tower, liquid-liquid extraction occurs, and extraction phase is sent to azeotropy rectification column, and raffinate phase is admitted to solvent recovery
Top of tower recycling design；(2) azeotropy rectification column tower bottom obtains the acetate products of high-purity, and the product at top is sent to phase-splitter
In；(3) organic phase in phase-splitter is sent extraction tower bottom back to and is recycled, and water phase is sent into solvent recovery tower；(4) solvent recovery tower
Tower bottom obtains the waste water for meeting emission request, and overhead product, which enters in phase-splitter, to be recycled；The isopropanol/isopropyl acetate binary
The mass ratio of isopropanol and isopropyl acetate is 1: 3.5 ~ 20 in mixture.
2. method according to claim 1, which is characterized in that the process conditions of extraction tower are as follows: normal pressure and operation temperature 10 ~
Between 50 DEG C, 20 ~ 30 pieces of theoretical plates, spirit of vinegar and extractant mass ratio are 1: 1 ~ 3.5；The process conditions of azeotropy rectification column are as follows:
Normal pressure, for number of theoretical plate at 25 ~ 35 pieces, feed tray position is the 12nd ~ 17 piece of theoretical plate；The process conditions of solvent recovery tower are as follows:
Normal pressure, for number of theoretical plate at 6 ~ 12 pieces, feed entrance point is tower top.
3. method according to claim 1, which is characterized in that this method be suitable for acetic acid quality fraction range 10 ~ 40% it
Between acetic acid waste liquid dehydration.
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| CN201910455822.1A CN110156590A (en) | 2019-05-29 | 2019-05-29 | A method of spirit of vinegar is recycled based on extraction/azeotropic distillation coupling technique |
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| CN201910455822.1A CN110156590A (en) | 2019-05-29 | 2019-05-29 | A method of spirit of vinegar is recycled based on extraction/azeotropic distillation coupling technique |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110833701A (en) * | 2019-11-20 | 2020-02-25 | 榆林学院 | Device for purifying acetic acid in vinyl acetate production by ethylene method |
| CN111348998A (en) * | 2020-04-17 | 2020-06-30 | 湖北三里枫香科技有限公司 | Energy-saving environment-friendly acetic acid production process |
| CN113754522A (en) * | 2021-10-12 | 2021-12-07 | 华东理工大学 | Separation process of water-propylene glycol monomethyl ether-propylene glycol ternary system |
| CN113968782A (en) * | 2021-11-24 | 2022-01-25 | 南通醋酸纤维有限公司 | Method for removing impurities in recycled acetic acid |
-
2019
- 2019-05-29 CN CN201910455822.1A patent/CN110156590A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110833701A (en) * | 2019-11-20 | 2020-02-25 | 榆林学院 | Device for purifying acetic acid in vinyl acetate production by ethylene method |
| CN111348998A (en) * | 2020-04-17 | 2020-06-30 | 湖北三里枫香科技有限公司 | Energy-saving environment-friendly acetic acid production process |
| CN113754522A (en) * | 2021-10-12 | 2021-12-07 | 华东理工大学 | Separation process of water-propylene glycol monomethyl ether-propylene glycol ternary system |
| CN113968782A (en) * | 2021-11-24 | 2022-01-25 | 南通醋酸纤维有限公司 | Method for removing impurities in recycled acetic acid |
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