CN112430196A - Method and device for refining adiponitrile - Google Patents
Method and device for refining adiponitrile Download PDFInfo
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- CN112430196A CN112430196A CN202011054329.8A CN202011054329A CN112430196A CN 112430196 A CN112430196 A CN 112430196A CN 202011054329 A CN202011054329 A CN 202011054329A CN 112430196 A CN112430196 A CN 112430196A
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- BTGRAWJCKBQKAO-UHFFFAOYSA-N adiponitrile Chemical compound N#CCCCCC#N BTGRAWJCKBQKAO-UHFFFAOYSA-N 0.000 title claims abstract description 316
- 238000007670 refining Methods 0.000 title claims abstract description 50
- 238000000034 method Methods 0.000 title claims abstract description 48
- BGTOWKSIORTVQH-UHFFFAOYSA-N cyclopentanone Chemical compound O=C1CCCC1 BGTOWKSIORTVQH-UHFFFAOYSA-N 0.000 claims abstract description 150
- 239000012535 impurity Substances 0.000 claims abstract description 103
- 239000000047 product Substances 0.000 claims description 42
- 239000000945 filler Substances 0.000 claims description 33
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 20
- 239000012043 crude product Substances 0.000 claims description 18
- 239000000706 filtrate Substances 0.000 claims description 15
- 238000010992 reflux Methods 0.000 claims description 15
- 238000001914 filtration Methods 0.000 claims description 9
- 238000012856 packing Methods 0.000 claims description 9
- 238000000926 separation method Methods 0.000 claims description 6
- 238000001816 cooling Methods 0.000 claims description 4
- 150000002391 heterocyclic compounds Chemical class 0.000 abstract description 8
- 238000009833 condensation Methods 0.000 abstract description 4
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 39
- 229910021529 ammonia Inorganic materials 0.000 description 18
- 238000003860 storage Methods 0.000 description 18
- 239000007789 gas Substances 0.000 description 17
- 239000000463 material Substances 0.000 description 17
- XZUDGZXKOFPLBC-UHFFFAOYSA-N 5-cyanopentanamide Chemical compound NC(=O)CCCCC#N XZUDGZXKOFPLBC-UHFFFAOYSA-N 0.000 description 14
- WNLRTRBMVRJNCN-UHFFFAOYSA-N adipic acid Chemical compound OC(=O)CCCCC(O)=O WNLRTRBMVRJNCN-UHFFFAOYSA-N 0.000 description 14
- 239000007788 liquid Substances 0.000 description 14
- 238000002425 crystallisation Methods 0.000 description 13
- 230000008025 crystallization Effects 0.000 description 13
- 238000001704 evaporation Methods 0.000 description 13
- 150000002576 ketones Chemical class 0.000 description 13
- 230000008020 evaporation Effects 0.000 description 10
- SKUPALMUTWEAPI-UHFFFAOYSA-N 5-cyanopentanoic acid Chemical compound OC(=O)CCCCC#N SKUPALMUTWEAPI-UHFFFAOYSA-N 0.000 description 8
- 238000001514 detection method Methods 0.000 description 8
- NAQMVNRVTILPCV-UHFFFAOYSA-N hexane-1,6-diamine Chemical compound NCCCCCCN NAQMVNRVTILPCV-UHFFFAOYSA-N 0.000 description 8
- 235000011037 adipic acid Nutrition 0.000 description 7
- 239000001361 adipic acid Substances 0.000 description 7
- 238000006243 chemical reaction Methods 0.000 description 7
- 239000000203 mixture Substances 0.000 description 7
- 239000013078 crystal Substances 0.000 description 5
- 230000000052 comparative effect Effects 0.000 description 4
- 238000006482 condensation reaction Methods 0.000 description 4
- 239000000539 dimer Substances 0.000 description 4
- 150000002825 nitriles Chemical class 0.000 description 4
- 238000000746 purification Methods 0.000 description 4
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 3
- -1 ammonia Chemical compound 0.000 description 3
- 235000011114 ammonium hydroxide Nutrition 0.000 description 3
- 238000005262 decarbonization Methods 0.000 description 3
- 238000011161 development Methods 0.000 description 3
- 238000006116 polymerization reaction Methods 0.000 description 3
- 238000004064 recycling Methods 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- GOJUJUVQIVIZAV-UHFFFAOYSA-N 2-amino-4,6-dichloropyrimidine-5-carbaldehyde Chemical group NC1=NC(Cl)=C(C=O)C(Cl)=N1 GOJUJUVQIVIZAV-UHFFFAOYSA-N 0.000 description 2
- 229920002302 Nylon 6,6 Polymers 0.000 description 2
- 239000004952 Polyamide Substances 0.000 description 2
- 239000003153 chemical reaction reagent Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000000835 fiber Substances 0.000 description 2
- RRAMGCGOFNQTLD-UHFFFAOYSA-N hexamethylene diisocyanate Chemical compound O=C=NCCCCCCN=C=O RRAMGCGOFNQTLD-UHFFFAOYSA-N 0.000 description 2
- 238000009776 industrial production Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 229920002647 polyamide Polymers 0.000 description 2
- 238000003786 synthesis reaction Methods 0.000 description 2
- 229940008841 1,6-hexamethylene diisocyanate Drugs 0.000 description 1
- FRMJZJUVLPFLAB-UHFFFAOYSA-N 2-iminocyclopentane-1-carbonitrile Chemical compound N=C1CCCC1C#N FRMJZJUVLPFLAB-UHFFFAOYSA-N 0.000 description 1
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 1
- 239000005057 Hexamethylene diisocyanate Substances 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 239000013556 antirust agent Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 238000007333 cyanation reaction Methods 0.000 description 1
- SVPZJHKVRMRREG-UHFFFAOYSA-N cyclopentanecarbonitrile Chemical compound N#CC1CCCC1 SVPZJHKVRMRREG-UHFFFAOYSA-N 0.000 description 1
- 238000006114 decarboxylation reaction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
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Classifications
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C253/00—Preparation of carboxylic acid nitriles
- C07C253/32—Separation; Purification; Stabilisation; Use of additives
- C07C253/34—Separation; Purification
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention provides a method and a device for refining adiponitrile. According to the method for refining adiponitrile, cyclopentanone in the crude adiponitrile is removed firstly, so that the cyclopentanone can be prevented from generating a large amount of heterocyclic compounds and tar through self-condensation in the subsequent steps, the product quality of the adiponitrile is reduced, the adiponitrile content in the product obtained after removing light component impurities and heavy component impurities is more than 99.8%, and the ICCP content is less than 200 ppm; can well meet the quality requirement of downstream products on adiponitrile.
Description
Technical Field
The invention relates to the technical field of chemical industry, in particular to a method and a device for refining adiponitrile.
Background
Adiponitrile (ADN) also known as 1, 4-dicyanobutane, formula NC (CH)3)4CN is colorless oily liquid, has slight smell and stable property. The polyamide fiber is mainly used for producing intermediate hexamethylene diamine of polyamide fiber, rubber accelerator and antirust agent: addition of adiponitrile to hydrogenAnd (3) generating hexamethylene diamine, and reacting the hexamethylene diamine with adipic acid to generate nylon 66 salt under a strict material ratio. Adiponitrile, an important intermediate in the synthesis of nylon 66, is the most prominent and valuable industrial use for adiponitrile development. Hexamethylenediamine can also synthesize 1, 6-Hexamethylene Diisocyanate (HDI), which is another important application of the development of a downstream product chain of adiponitrile; with the rapid development of technology, the use of adiponitrile in the fields of light industry, electronics and other organic synthesis is also gradually developed.
The products for the industrial production of ADN include not only adiponitrile, which is the main product, but also many by-products, and therefore, how to purify ADN more economically and efficiently in industrial production is a goal pursued. For example, the prior art discloses a method for refining adiponitrile, which comprises the following steps:
a. preparing a crude nitrile mixture by using adipic acid and ammonia in a cyanation reactor, and obtaining a mixture mainly containing adiponitrile after washing, filtering, decanting and drying; the mixture contains impurities mainly including delta-cyano valeramide, delta-cyano valeramide and Imido Cyano Cyclopentane (ICCP), and the content of all the other impurities is less than 1%; preheating the mixture containing adiponitrile to 170-220 ℃, then sending the mixture into a tray at the 23 rd layer, the 25 th layer or the 27 th layer of a light component removal tower for separation and purification, collecting the adiponitrile at the bottom of the tower, and discharging light components at the top of the tower;
b. the temperature of the adiponitrile collected at the bottom of the tower is controlled at 180-230 ℃, the adiponitrile enters a lower tray of a de-heavy tower for separation and purification, the refined adiponitrile is discharged from the top of the de-heavy tower, condensed by a condenser and cooled to 30-50 ℃ in an adiponitrile cooler, and finally enters a storage tank for storage. Wherein, the temperature of the material at the bottom of the light component removal tower is heated and circulated by a reboiler by a pump, the temperature is controlled within 200-240 ℃, and the pressure at the bottom of the light component removal tower is controlled within 5-20 KPaA.
In the method for refining adiponitrile disclosed in the above document, cyclopentanone in the crude nitrile mixture is self-condensed to produce heterocyclic compounds and tar under the high temperature condition of the light ends removal column, resulting in a reduction in the product quality of adiponitrile.
Disclosure of Invention
Therefore, the technical problem to be solved by the invention is to overcome the defects of low quality and low yield of adiponitrile products prepared by the adiponitrile refining method in the prior art, thereby providing the adiponitrile refining method and the adiponitrile refining device.
Therefore, the invention provides the following technical scheme:
a method for refining adiponitrile includes removing cyclopentanone from crude adiponitrile.
Optionally, comprising separating an azeotrope of cyclopentanone and water from the crude adiponitrile to achieve cyclopentanone removal.
Optionally, a ketone removing tower is adopted to remove cyclopentanone, the temperature at the bottom of the ketone removing tower is controlled to be 140-;
the de-ketonizing tower is a filler rectifying tower.
Compared with a packed de-ketonizer, the temperature of the bottom of the plate de-ketonizer cannot be reduced to the limited temperature of the bottom of the de-ketonizer, and cyclopentanone is easy to polymerize to form heterocyclic compounds and tar due to too high temperature, so that the quality of adiponitrile is influenced finally.
Optionally, the pressure of the top of the ketone removing tower is 100-200mmHg, and the temperature of the top of the ketone removing tower is controlled to be 40-60 ℃.
Optionally, the reflux ratio of the de-ketonizer is between 1 and 3.
And the method also comprises the step of carrying out light component removal treatment on the crude adiponitrile product subjected to cyclopentanone removal, wherein the light component removal treatment is carried out by adopting a filler light component removal tower, the temperature at the bottom of the filler light component removal tower is controlled to 160-195 ℃, the pressure at the bottom of the filler light component removal tower is 20-65mmHg, the temperature at the top of the filler light component removal tower is controlled to 140-180 ℃, and the pressure at the top of the filler light component removal tower is 5-50 mm.
Optionally, the method further comprises the step of carrying out heavy removal treatment on the crude adiponitrile subjected to light removal treatment, wherein the heavy removal treatment is carried out by adopting a filler heavy removal tower, the temperature at the bottom of the heavy removal tower is controlled to 160-195 ℃, the pressure at the bottom of the heavy removal tower is 20-65mmHg, the temperature at the top of the heavy removal tower is controlled to 150-180 ℃, and the pressure at the top of the heavy removal tower is 10-50 mmHg.
Optionally, the reflux ratio of the de-heavies column is from 0.8 to 3.0.
Optionally, partially recycling the removed cyclopentanone to the top of the ketone removing tower after condensation for controlling the temperature of the top of the ketone removing tower;
and/or condensing light component impurities obtained by separation at the top of the packed light component removal tower, then partially circulating the condensed light component impurities to the top of the packed light component removal tower for controlling the temperature at the top of the tower, crystallizing the rest of the condensed light component impurities, crystallizing most ICCP contained in the light component impurities out, filtering the crystals to obtain filtrate, wherein the content of adiponitrile in the filtrate is higher than 92 percent, and circulating the filtrate to the packed light component removal tower to recover the adiponitrile in the filtrate;
and/or condensing adiponitrile separated from the top of the filler de-weighting tower, then recycling part of the adiponitrile into the filler de-weighting tower for controlling the temperature at the top of the filler de-weighting tower, and cooling the rest part of the adiponitrile to obtain the adiponitrile product.
The removed cyclopentanone (including water, ammonia and other light component impurities with low boiling point) is cooled and then partially circulated to the top of the de-ketonizer for controlling the temperature of the top of the de-ketonizer, so that adiponitrile is prevented from being carried in the removed cyclopentanone and other impurities, and the yield of adiponitrile is improved; and impurities containing cyclopentanone for circulation only form circulation at the top of the de-ketonizer, which does not cause accumulation of cyclopentanone in the de-ketonizer, and crude adiponitrile separated from the bottom of the de-ketonizer does not contain cyclopentanone.
Optionally, the temperature of the condensed light component impurities is 80-100 ℃;
optionally, in order to reduce the temperature in the bottom of the light component removal column, the light component removal column may be split into two columns, before the heavy component removal treatment is performed on the crude adiponitrile subjected to the light component removal treatment, a secondary light component removal treatment is performed on the crude adiponitrile subjected to the first light component removal column, the secondary light component removal treatment is performed by using a second filler light component removal column, the temperature at the bottom of the second filler light component removal column is controlled to 160-195 ℃, the pressure at the bottom of the second filler light component removal column is 20-65mmHg, the temperature at the top of the second filler light component removal column is controlled to 140-180 ℃, and the pressure at the top of the second filler light.
Optionally, evaporating and condensing heavy component impurities obtained by the heavy component removal treatment, and then circulating the heavy component impurities to a heavy component removal tower;
the evaporation temperature is controlled to be 150-190 ℃, and the pressure is 10-60 mmHg;
and condensing adiponitrile obtained by the de-weight treatment, then circulating part of the adiponitrile into the filler de-weight tower for controlling the temperature at the top of the filler de-weight tower, and further cooling the rest part of the adiponitrile to obtain the adiponitrile product.
Alternatively, the crude adiponitrile refers to an adiponitrile product containing impurities such as cyclopentanone, including but not limited to an unrefined cyclopentanone-containing adiponitrile product produced by an existing production process or a refined cyclopentanone-containing adiponitrile product produced by an existing process, provided that the content of cyclopentanone is not less than 0.1 wt%, which belongs to the crude adiponitrile product of the invention.
For example, the crude adiponitrile product has an adiponitrile content of 88 to 92 wt%, a water content of 7.0 to 8.0 wt%, a 5-cyanovaleramide content of 0.8 to 2.0 wt%, an ICCP content of 0.2 to 0.5 wt%, a cyclopentanone content of 0.1 to 0.5 wt%, and a residual impurity content of less than 0.5 wt%.
The invention also provides a refining device of adiponitrile, which comprises,
the de-ketonizing device comprises an adiponitrile crude product inlet, a cyclopentanone-containing impurity outlet and a crude adiponitrile outlet;
the de-lightening device comprises a crude adiponitrile inlet and an adiponitrile solution outlet, and the crude adiponitrile inlet is communicated with the crude adiponitrile outlet of the de-ketonizer;
the de-weighting device comprises an adiponitrile outlet and an adiponitrile solution inlet, and the adiponitrile solution inlet is communicated with the adiponitrile solution outlet of the de-weighting device.
Optionally, the de-ketonizing apparatus is a packed rectification column.
Optionally, the refining apparatus further comprises a de-ketonizer; the bottom of the de-ketonizer is communicated with a de-ketonizer and forms a circulation.
Optionally, the refining apparatus further comprises a de-ketonizer; the de-ketonizing apparatus further comprises a cyclopentanone-containing impurity inlet; and the impurity outlet containing cyclopentanone is communicated with the impurity inlet containing cyclopentanone through a de-ketonizing condenser.
Optionally, the de-ketonizing condenser is in communication with a vacuum device.
Optionally, the refining apparatus further comprises a light ends removal condenser; the light component impurity outlet is communicated with the light component impurity inlet through a light component removal condenser.
Optionally, the lightness-removing condenser is communicated with the crude adiponitrile inlet of the lightness-removing device through a crystallizing device and a filtering device in sequence.
Optionally, the crystallization device comprises a crystallization feed tank and a crystallization tank which are communicated in sequence; the filtering device comprises a filter and a filtrate storage tank which are communicated in sequence.
Optionally, the refining device further comprises a light component removal reboiler, and the bottom of the packed light component removal tower is communicated with the light component removal reboiler and forms a circulation.
Optionally, the lightness-removing apparatus comprises 1 or 2 packed lightness-removing columns;
when the lightness-removing device comprises 1 packed lightness-removing column, the adiponitrile solution outlet of the lightness-removing column is communicated with the adiponitrile solution inlet of the weight-removing device.
When the lightness-removing device comprises 2 packed lightness-removing columns, the lightness-removing device comprises a first packed lightness-removing column and a second packed lightness-removing column; an adiponitrile solution outlet of the first packing lightness-removing tower is communicated with an adiponitrile solution inlet at the top of the second packing lightness-removing tower, and a bottom outlet of the second packing lightness-removing tower is communicated with an adiponitrile solution inlet of the weight removal device.
Optionally, the top outlet of the second packed light component removal tower is communicated with the second light component impurity inlet of the first packed light component removal tower through a second light component removal tower condenser.
Optionally, the heavy component impurity outlet of the de-weighting device is communicated with the recovered adiponitrile inlet of the de-weighting device sequentially through the evaporator and the evaporative condenser.
Optionally, the adiponitrile outlet of the de-weighting device is respectively communicated with the adiponitrile inlet of the de-weighting device and the adiponitrile storage tank through a de-weighting condenser;
the de-weighting condenser is communicated with a de-weighting vacuum device.
Optionally, the refining apparatus further comprises a de-heavy reboiler; the de-weighting device is a filler de-weighting tower, and the bottom of the filler de-weighting tower is communicated with a de-weighting reboiler to form circulation.
The technical scheme of the invention has the following advantages:
1. most of the existing methods for refining adiponitrile separate and remove light component impurities in the crude adiponitrile, and then remove heavy component impurities to obtain the adiponitrile product. Wherein the light component impurities include water, cyclopentanone, ammonia, 2-cyano-1-Iminocyclopentane (ICCP), etc.; heavy component impurities include 5-cyanovaleramide, 5-cyanovaleric acid (ammonium), and the like. In order to remove most of light component impurities in the crude adiponitrile product, the materials at the lower part of the light component removal tower need to be heated to 200 ℃ and 240 ℃, and the pressure is controlled to be 37.5-150 mmHg; under the condition, however, cyclopentanone can undergo self-condensation reaction to generate a large amount of heterocyclic compounds and tar, and adiponitrile can undergo self-polymerization to generate adiponitrile dimer and tar; resulting in a reduction in the product quality and yield of adiponitrile.
The inventor finds that the light component impurities can be separated and removed step by step through a large amount of process researches: firstly, cyclopentanone is removed, and then other light component impurities are separated, so that the cyclopentanone can be effectively prevented from self-condensing to generate heterocyclic compounds and tar in the subsequent treatment process. Compared with the traditional method for purifying adiponitrile, the method for refining adiponitrile provided by the invention has the advantages that cyclopentanone in the crude adiponitrile product is removed firstly, and the cyclopentanone is prevented from undergoing self-condensation in the subsequent rectification step to generate heterocyclic compounds and tar, so that the product quality and yield of adiponitrile are reduced. The adiponitrile content in the product refined by the adiponitrile refining method provided by the invention is more than 99.8%, and the ICCP content is less than 200 ppm; can well meet the quality requirement of downstream products on adiponitrile.
2. The method for refining adiponitrile provided by the invention utilizes the characteristic that cyclopentanone and water can form an azeotrope, the azeotropic point is 93.5 ℃, and the cyclopentanone does not undergo a condensation reaction at the temperature, so that the cyclopentanone in the crude adiponitrile product is removed at the temperature lower than the temperature at which the cyclopentanone can undergo the condensation reaction, and the phenomenon that the cyclopentanone undergoes a self-condensation reaction to generate a heterocyclic compound and tar in the subsequent steps is avoided, thereby improving the quality of adiponitrile.
3. When the temperature of the adiponitrile for rectification is higher than 195 ℃, the adiponitrile is polymerized to form dimer, and acid substances such as 5-cyanovaleric acid and the like are decarboxylated and polymerized to generate tar, so that the temperature of each rectifying tower kettle is strictly controlled to be lower than 195 ℃, preferably lower than 190 ℃, and the adiponitrile dimer and the tar can be effectively prevented from being generated; the packed tower can reduce the pressure drop of the rectifying tower, reduce the temperature of the tower kettle and avoid the polymerization of adiponitrile and the decarboxylation polymerization of acidic substances; the method for refining adiponitrile provided by the invention can further improve the quality and yield of adiponitrile by controlling the temperature of the de-ketonizer and adopting the packed tower.
4. According to the method for refining adiponitrile, the reflux ratio of the de-ketonizer is controlled, and the temperature and the pressure of the de-ketonizer are combined, so that the low-boiling-point light components such as water, cyclopentanone and ammonia are removed from the top of the tower under the vacuum condition of relatively low temperature, and the removed cyclopentanone is ensured not to carry out adiponitrile.
5. The method for refining adiponitrile provided by the invention can prevent adiponitrile dimer from being generated due to long-time high-temperature heating of adiponitrile by controlling the temperature and the pressure of the light component removal tower, thereby preventing the yield and the quality of adiponitrile from being reduced.
6. According to the method for refining adiponitrile provided by the invention, a large amount of adiponitrile can be entrained in light component impurities separated from the top of the filler lightness-removing column, and the amount of adiponitrile entrained in the light component impurities can be reduced by circulating part of the condensed light component impurities to the filler lightness-removing column to control the temperature at the top of the filler lightness-removing column; meanwhile, the content of adiponitrile in filtrate obtained after the residual light component impurities are crystallized and filtered (ICCP is crystallized and filtered out), the filtrate with high adiponitrile content is directly sent back to the filler lightness-removing tower to recover adiponitrile, the yield of adiponitrile is improved, and the ICCP is removed through crystallization, so that the ICCP cannot be accumulated in a system.
7. According to the method for refining adiponitrile provided by the invention, the mixture of adiponitrile and heavy components and second light component impurities are obtained by carrying out secondary light component removal on the crude adiponitrile subjected to light component removal treatment before heavy component removal treatment, so that the light component impurities, especially ICCP, can be completely removed, and the influence of the ICCP on the quality of adiponitrile is prevented.
8. In the method for refining adiponitrile provided by the invention, the impurities of the second light component mainly comprise ICCP and adiponitrile; the second light component impurity is cooled and then circulated to the first filler lightness-removing tower for lightness-removing treatment again, so that the effect of removing ICCP in adiponitrile can be improved.
9. According to the refining device for adiponitrile, the ketonizing device is arranged, and by utilizing the azeotropic characteristic of cyclopentanone and water, cyclopentanone, water, ammonia and most light component impurities in the crude product of adiponitrile are removed, so that the cyclopentanone can be prevented from undergoing self-condensation in the subsequent rectification process to generate a large amount of heterocyclic compounds and tar; resulting in a reduction in the product quality of adiponitrile. The adiponitrile content in the product refined by the adiponitrile refining device provided by the invention is more than 99.8%, and the ICCP content is less than 200 ppm; can well meet the quality requirement of downstream products on adiponitrile.
10. The refining device of adiponitrile provided by the invention can further reduce the temperature of the tower kettle of the filler lightness-removing tower by arranging 2 filler lightness-removing towers which are connected in series, thereby reducing the content of ICCP and adiponitrile dimer in the product and improving the quality of adiponitrile.
11. The refining device of adiponitrile provided by the invention has the advantages that the reboiler is respectively arranged at the bottom of the ketone removing tower, the bottom of the light component removing tower and the bottom of the heavy component removing tower, the driving force of rectification is provided, the temperature of the bottom materials of each tower is controlled, and the quality of adiponitrile is improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
FIG. 1 is a schematic view of an apparatus for refining adiponitrile according to the present invention;
FIG. 2 is a schematic view of another apparatus for refining adiponitrile according to the present invention.
Reference numerals:
1. a de-ketonizing reboiler; 2. a ketone removing tower; 3. an evaporation reboiler; 4. an adiponitrile storage tank; 5. a de-ketonizing condenser; 6. a crude adiponitrile storage tank; 7. a vacuum pump; 8. a first vacuum device; 9. a first lightness-removing condenser; 10. a raffinate evaporator; 11. a filtrate storage tank; 12. a filter; 13. a crystallization feed tank; 14. a first lightness-removing column; 15. a first lightness-removing reboiler; 16. a crystallization tank; 17. a second lightness-removing condenser; 18. a second vacuum device; 19. a second lightness-removing tower; 20. a second lightness-removing reboiler; 21. a de-heavy reboiler; 22. a de-weighting tower; 23. a de-weighting condenser; 24. a de-weighting vacuum device; 25. an adiponitrile condenser; 26. and (4) evaporating the condenser.
Detailed Description
The following examples are provided to further understand the present invention, not to limit the scope of the present invention, but to provide the best mode, not to limit the content and the protection scope of the present invention, and any product similar or similar to the present invention, which is obtained by combining the present invention with other prior art features, falls within the protection scope of the present invention.
The examples do not show the specific experimental steps or conditions, and can be performed according to the conventional experimental steps described in the literature in the field. The reagents or instruments used are not indicated by manufacturers, and are all conventional reagent products which can be obtained commercially.
In order to reduce the pressure drop of the column and the temperature of the column bottom, a packed column (comprising structured packing and random packing) is adopted in each example, and a plate column is adopted in a comparative example.
In order to illustrate the effects of the present invention, in the following examples, an unrefined product obtained by reacting adipic acid with ammonia was used as a purification target, and the contents of the respective components in the product were slightly different because the process conditions and the raw materials were not completely identical, and generally, the unrefined product obtained by the process had an adiponitrile content of 88 to 92 wt%, a water content of 7.0 to 8.0 wt%, a 5-cyanovaleramide content of 1.0 to 2.0 wt%, an ICCP content of 0.2 to 0.5 wt%, and a cyclopentanone content of 0.1 to 0.5 wt%. It should be noted that the crude adiponitrile according to the present invention is not limited to the purification objects used in the following examples, and the crude adiponitrile according to the present invention refers to an adiponitrile product containing cyclopentanone and having a content of not less than 0.1 wt%, and includes, but is not limited to, an unrefined adiponitrile product produced by any existing production process or a adiponitrile product refined by an existing process, as long as the content of cyclopentanone is not less than 0.1 wt%.
Example 1
This example provides an apparatus for purifying adiponitrile, as shown in FIG. 1, comprising,
the de-ketonizer 2 is a packing rectifying tower and comprises an adiponitrile crude product inlet, a crude adiponitrile outlet, a cyclopentanone-containing impurity outlet and a cyclopentanone-containing impurity inlet. A de-ketone reboiler 1 is arranged on the outer side of the bottom of the de-ketone tower 2, and the bottom material of the de-ketone tower 2 is heated by the de-ketone reboiler 1 and then circulates to the bottom of the de-ketone tower 2, so that the temperature of the bottom material of the de-ketone tower 2 is controlled, and power is provided for the operation of the de-ketone tower 2;
an impurity outlet containing cyclopentanone of the de-ketonizer 2 is communicated with an inlet of a de-ketonizer condenser 5, and a condensate outlet of the de-ketonizer condenser 5 is respectively communicated with the impurity inlet containing cyclopentanone of the de-ketonizer 2 and a pipeline for recovering ammonia; the impurity outlet containing cyclopentanone is communicated with the impurity inlet containing cyclopentanone through a de-ketonizer 5, and forms a circulation at the top of the de-ketonizer 2, so as to control the temperature of the top material of the de-ketonizer 2 and prevent the gas phase at the top of the de-ketonizer from taking away adiponitrile;
the de-ketonizing condenser 5 is also communicated with a vacuum pump 7 and is used for controlling the vacuum degree of the de-ketonizing tower 2.
A first lightness-removing column 14 which is a packed column and comprises a crude adiponitrile inlet, a first light component impurity outlet, a first light component impurity inlet and a first adiponitrile solution outlet; the crude adiponitrile outlet of the ketone removing tower 2 is communicated with the crude adiponitrile inlet of a first lightness-removing tower 14 through a crude adiponitrile storage tank 6, a first lightness-removing reboiler 15 is arranged on the outer side of the bottom of the first lightness-removing tower 14, and the bottom material of the first lightness-removing tower 14 is heated by the first lightness-removing reboiler 15 and then circulates to the bottom of the first lightness-removing tower 14, so that the temperature of the bottom material of the first lightness-removing tower 14 is controlled, and power is provided for the operation of the first lightness-removing tower;
a first light component impurity outlet of the first lightness-removing column 14 is communicated with an inlet of a first lightness-removing condenser 9, a condensate outlet of the first lightness-removing condenser 9 is respectively communicated with a crystallization feeding tank 13 and a first light component impurity inlet of the first lightness-removing column 14, the first lightness-removing column 14 is communicated with the first light component impurity inlet through the first lightness-removing condenser 9, a circulation is formed at the top of the first lightness-removing column 14, and the circulation is used for controlling the temperature of materials at the top of the first lightness-removing column 14 and carrying away adiponitrile from a gas phase as little as possible;
the crystallization feeding tank 13 is communicated with a crude adiponitrile inlet of the first lightness-removing column 14 sequentially through a crystallization tank 16, a filter 12, a filtrate storage tank 11 and a crude adiponitrile storage tank 6;
the first lightness-removing condenser 9 is communicated with the first vacuum device 8 and is used for controlling the vacuum degree of the first lightness-removing tower 14; the first lightness-removing column 14 further comprises a second light component impurity inlet.
And a second light component removal tower 19 which is a packed tower and comprises a second light component impurity outlet, an adiponitrile solution inlet and an adiponitrile solution outlet. An adiponitrile solution inlet on the side line at the top of the second lightness-removing column 19 is communicated with an adiponitrile solution outlet at the bottom of the first lightness-removing column 14; the second light component impurity outlet is communicated with a second light component impurity inlet at the bottom of the first light component removal tower 14 through a second light component removal condenser 17; the second lightness-removing condenser 17 is also communicated with a second vacuum device 18 and is used for controlling the vacuum degree of a second lightness-removing tower 19;
a second lightness-removing reboiler 20 is arranged on the outer side of the bottom of the second lightness-removing tower 19, and the material at the bottom of the second lightness-removing tower 19 is heated by the second lightness-removing reboiler 20 and then circulates to the bottom of the second lightness-removing tower 19, so that the temperature of the material at the bottom of the second lightness-removing tower 19 is controlled, and power is provided for the operation of the second lightness-removing tower 19;
the heavy component removing tower 22 is a packed tower and comprises an adiponitrile solution inlet, an adiponitrile outlet, an adiponitrile inlet, an adiponitrile outlet containing heavy components and an evaporated liquid inlet. The adiponitrile solution inlet is communicated with the adiponitrile solution outlet of the second light component removal tower 19; the adiponitrile outlet is communicated with the inlet of a de-heavy condenser 23, and the condensate outlet of the de-heavy condenser 23 is respectively communicated with the adiponitrile inlet of a de-heavy tower 22 and an adiponitrile condenser 25; the adiponitrile outlet of the de-heavy tower 22 is communicated with the adiponitrile inlet through a de-heavy condenser 23 to form a cycle; for controlling the temperature of the top material of the de-weighting tower 22 and preventing heavy component impurities from being carried out of the gas phase at the top of the tower; the adiponitrile condenser 25 is also communicated with the adiponitrile storage tank 4;
the adiponitrile outlet containing the heavy components is communicated with the raffinate evaporator 10, the top outlet of the raffinate evaporator 10 is communicated with an evaporated liquid inlet of the de-weighting tower 22 through an evaporative condenser 26, and the evaporative condenser 26 and the de-weighting condenser 23 are respectively communicated with a de-weighting vacuum device 24 and used for controlling the vacuum degrees of the de-weighting tower 22 and the raffinate evaporator 10; a heavy component removal reboiler 21 is arranged on the outer side of the bottom of the heavy component removal tower 22, and the bottom material of the heavy component removal tower 22 is heated by the heavy component removal reboiler 21 and then circulated to the bottom of the heavy component removal tower 22 to control the temperature of the bottom material of the heavy component removal tower 22; the outer side of the bottom of the raffinate evaporator 10 is provided with an evaporation reboiler 3, and the bottom material of the raffinate evaporator 10 is heated by the evaporation reboiler 3 and then circulated to the bottom of the raffinate evaporator 10 to control the temperature of the bottom material of the raffinate evaporator 10.
As an alternative embodiment of the above apparatus, the second light ends removal column 19 may not be provided, and as shown in FIG. 2, the adiponitrile solution outlet at the bottom of the first light ends removal column 14 is directly connected to the adiponitrile solution inlet of the heavy ends removal column 22.
Example 2
This example provides a method for refining adiponitrile, using the apparatus shown in FIG. 2, comprising the steps of:
the crude product which is mainly adiponitrile and is obtained by the reaction of adipic acid and ammonia is the crude product of adiponitrile. Through detection, the content of each component in the adiponitrile crude product is as follows: adiponitrile 89.5%, water 7.68%, cyclopentanone 0.378%, ICCP about 0.376%, ammonia 0.323%, and other light components 0.08%, and heavy components (including 5-cyanovaleramide, 5-cyanovaleric acid, dimers of adiponitrile, etc.) about 1.663% (of which 5-cyanovaleramide is 1.345%).
And (3) removing ketone:
feeding the adiponitrile crude product into the middle part of a de-ketonizer, controlling the pressure of the de-ketonizer to be 150mmHg, the temperature of the top of the de-ketonizer to be 55 ℃, and the reflux ratio to be 1.2; impurities containing cyclopentanone (mainly ammonia, azeotrope of cyclopentanone and water, water and part of light component impurities) are obtained from the tower top through rectification treatment, most of condensate of the impurities containing cyclopentanone condensed by the de-ketonizing condenser is used as reflux liquid to be circulated to the tower top of the de-ketonizing tower so as to control the temperature of the tower top, the rest is sent to an ammonia water storage tank, and the uncondensed gas containing the cyclopentanone impurities is sent to a decarbonization tower to recover ammonia gas therein;
controlling the temperature at the bottom of the de-ketonizer to be 160 ℃ and the pressure to be 160mmHg, and obtaining the crude adiponitrile at the bottom of the de-ketonizer.
And (3) light component removal:
crude adiponitrile obtained at the bottom of the de-ketonizer, namely the crude adiponitrile without cyclopentanone, enters the middle upper part of the light component removal tower, the temperature at the top of the light component removal tower is controlled at 140 ℃, and the pressure is 5 mmHg; condensing light component impurities discharged from the top of the light component removal tower to 85 ℃, and then partially circulating the light component impurities to the top of the light component removal tower for controlling the temperature of the top of the light component removal tower; and the rest part is subjected to ICCP crystallization, and the filtrate after filtering off ICCP crystals is returned to the crude adiponitrile storage tank to be mixed with crude adiponitrile, and is circulated to the light component removal tower to recover adiponitrile therein.
The temperature of the bottom of the light component removal tower is controlled to be 195 ℃; the pressure was 65mmHg, and a solution of adiponitrile containing little or no trace of ICCP was obtained at the bottom of the lightness-removing column.
A step of removing the weight:
the adiponitrile solution discharged from the bottom of the light component removal tower, namely the crude adiponitrile subjected to light component removal treatment enters the middle lower part of the heavy component removal tower, the reflux ratio of the heavy component removal tower is controlled to be 3.0, the temperature at the top of the tower is controlled to be 155 ℃, and the pressure is 10 mmHg; the bottom temperature was controlled at 185 ℃ and the pressure at 25 mmHg. After condensing the gas-phase adiponitrile discharged from the top of the de-heavy tower, partially circulating the gas-phase adiponitrile to the top of the de-heavy tower to control the temperature of the top of the de-heavy tower, and cooling the rest part to 30-50 ℃ to obtain an adiponitrile product, wherein the adiponitrile content in the adiponitrile product is 99.82% through detection; the ICCP content was 190 ppm; the VATP (2-amyl-4-amino-5, 6-trimethylenepyrimidine) content is 300 ppm; adiponitrile containing heavy component impurities (the heavy component impurities mainly comprise 5-cyanovaleramide, and also comprise trace 5-cyanovaleric acid, 2-amyl-4-amino-5, 6-trimethylenepyrimidine and 2-amino (3,4,5,6) -ditrimethylenepyridine) which is discharged from the bottom of the de-heavy tower and evaporated at 154 ℃ and 10mmHg, and adiponitrile gas phase containing trace heavy component impurities and an evaporation residual liquid are obtained, wherein the adiponitrile gas phase containing trace heavy component impurities is condensed and circulated to the lower part of the de-heavy tower to recover adiponitrile therein, and the evaporation residual liquid mainly comprises 5-cyanovaleramide and a small amount of adiponitrile, so the adiponitrile is sent to a reaction system for recycling.
Example 3
This example provides a method for refining adiponitrile, using the apparatus shown in FIG. 1, comprising the steps of:
the crude product which is mainly adiponitrile and is obtained by the reaction of adipic acid and ammonia is the crude product of adiponitrile. Through detection, the content of each component in the crude product is as follows: adiponitrile 88.7%, water 7.96%, cyclopentanone 0.14%, ICCP about 0.466%, ammonia 0.203%, and other light components 0.06%, and heavy components (including 5-cyanovaleramide, 5-cyanovaleric acid, dimer of adiponitrile, etc.) about 2.167% (of which 5-cyanovaleramide is 1.961%).
And (3) removing ketone:
feeding the crude adiponitrile into the middle part of a de-ketonizer, controlling the pressure of the top of the de-ketonizer to be 200mmHg, the temperature of the top of the de-ketonizer to be 60 ℃, and the reflux ratio to be 3; impurities containing cyclopentanone (mainly ammonia, azeotrope of cyclopentanone and water, water and part of light component impurities) are obtained from the tower top through rectification treatment, most of condensate of the impurities containing cyclopentanone condensed by the de-ketonizing condenser is used as reflux liquid to be circulated to the tower top of the de-ketonizing tower so as to control the temperature of the tower top, the rest is sent to an ammonia water storage tank, and the uncondensed gas containing the cyclopentanone impurities is sent to a decarbonization tower to recover ammonia gas therein;
the temperature of the bottom of the de-ketonizer is controlled at 165 ℃, the pressure is 210mmHg, and the crude adiponitrile is obtained at the bottom of the tower.
And (3) light component removal:
feeding crude adiponitrile obtained at the bottom of the de-ketonizer, namely the crude adiponitrile without cyclopentanone, into the middle lower part of the first light component removal tower, controlling the temperature at the top of the first light component removal tower to be 180 ℃ and the pressure to be 50 mmHg; condensing the first light component impurities discharged from the top of the first light component removal tower to 85 ℃, and then partially circulating the first light component impurities to the top of the first light component removal tower for controlling the temperature of the top of the first light component removal tower; and the rest part is subjected to ICCP crystallization, and the filtrate after filtering off ICCP crystals is returned to the crude adiponitrile storage tank to be mixed with crude adiponitrile, and is circulated to the light component removal tower to recover adiponitrile therein.
The temperature of the bottom of the first lightness-removing tower is controlled to be 190 ℃; the pressure was 60 mmHg. Feeding the adiponitrile solution discharged from the bottom of the first lightness-removing column into a second lightness-removing column, and controlling the temperature at the top of the second lightness-removing column to be 160 ℃ and the pressure to be 15 mmHg; the temperature of the bottom of the second lightness-removing tower is controlled to be 180 ℃; the pressure is 50 mmHg; and condensing second light component impurities (adiponitrile gas phase containing trace ICCP) discharged from the top of the second lightness-removing column, circulating the condensed second light component impurities to the lower part of the first lightness-removing column to remove the ICCP, and recovering the adiponitrile in the second light component impurities.
A step of removing the weight:
the adiponitrile solution discharged from the bottom of the second light component removal tower, namely the adiponitrile crude product subjected to secondary light component removal treatment enters the middle lower part of the heavy component removal tower, the reflux ratio of the heavy component removal tower is controlled to be 1.0, the temperature at the top of the tower is controlled to be 172 ℃, and the pressure is 20 mmHg; the temperature of the bottom of the column was controlled at 180 ℃ and the pressure at 50 mmHg. After the gas-phase adiponitrile discharged from the top of the de-heavy tower is condensed, part of the gas-phase adiponitrile circulates to the top of the de-heavy tower to control the temperature of the top of the de-heavy tower, and the rest part of the gas-phase adiponitrile is condensed to 30-50 ℃ again to obtain an adiponitrile product, wherein the adiponitrile content in the adiponitrile product is 99.89% through detection; ICCP content was 145 ppm; the VATP (2-amyl-4-amino-5, 6-trimethylenepyrimidine) content is 320 ppm;
adiponitrile (the heavy component impurities mainly comprise 5-cyanovaleramide, and trace 5-cyanovaleric acid, trace VATP and (2-amino (3,4,5,6) -ditrimethylenepyridine) containing the heavy component impurities discharged from the bottom of the de-heavy tower are evaporated at the temperature of 160 ℃ and the pressure of 15mmHg to obtain adiponitrile gas phase containing the trace heavy component impurities and an evaporation residual liquid, the adiponitrile gas phase containing the trace heavy component impurities is condensed and circulated to the lower part of the de-heavy tower to recover adiponitrile therein, and the evaporation residual liquid containing the heavy component impurities is sent to a reaction system to recover organic matters therein.
Example 4
This example provides a method for refining adiponitrile, using the apparatus shown in FIG. 1, comprising the steps of:
the crude product which is mainly adiponitrile and is obtained by the reaction of adipic acid and ammonia is the crude product of adiponitrile. Through detection, the content of each component in the crude product is as follows: adiponitrile 91.2%, water 7.09%, cyclopentanone 0.128%, ICCP about 0.206%, ammonia 0.204%, and other light components 0.05%, and heavy components (including 5-cyanovaleramide, 5-cyanovaleric acid, dimer of adiponitrile, etc.) about 1.12% (of which 5-cyanovaleramide is 0.92%).
And (3) removing ketone:
feeding the crude nitrile solution mainly containing adiponitrile into the middle part of a de-ketonizer, controlling the pressure of the top of the de-ketonizer to be 100mmHg, the temperature of the top of the de-ketonizer to be 40 ℃, and the reflux ratio to be 2; impurities containing cyclopentanone (mainly ammonia, azeotrope of cyclopentanone and water, water and part of light component impurities) are obtained from the tower top through rectification treatment, most of the impurities containing cyclopentanone are used as reflux liquid to be circulated to the tower top of the ketonization tower after being condensed by the ketonization condenser so as to control the temperature of the tower top, the rest part of the impurities are sent to an ammonia water storage tank, and the uncondensed gases containing cyclopentanone impurities are sent to a decarbonization tower to recover ammonia gas therein;
controlling the temperature of the bottom of the ketone removing tower to be 142 ℃ and the pressure to be 120 mmHg; crude adiponitrile is obtained at the bottom of the tower.
And (3) light component removal:
feeding crude adiponitrile obtained at the bottom of the de-ketonizer, namely the crude adiponitrile without cyclopentanone, into the middle part of a light component removal tower of a first tower, controlling the temperature at the top of the light component removal tower to be 160 ℃ and the pressure to be 15 mmHg; condensing the first light component impurities discharged from the top of the first light component removal tower to 90 ℃, and then partially circulating the first light component impurities to the top of the first light component removal tower for controlling the temperature of the top of the first light component removal tower; and the rest part is subjected to ICCP crystallization, and the filtrate after filtering off ICCP crystals is returned to the crude adiponitrile storage tank to be mixed with crude adiponitrile, and is circulated to the light component removal tower to recover adiponitrile therein.
The temperature of the bottom of the first lightness-removing tower is controlled at 180 ℃; the pressure is 50 mmHg;
feeding the adiponitrile solution discharged from the bottom of the first lightness-removing column into a second lightness-removing column, and controlling the temperature at the top of the second lightness-removing column to be 160 ℃ and the pressure to be 15 mmHg; the temperature of the bottom of the second lightness-removing tower is controlled at 180 ℃; the pressure is 50 mmHg; and condensing second light component impurities (adiponitrile gas phase containing trace ICCP) discharged from the top of the second lightness-removing column, circulating the condensed second light component impurities to the lower part of the first lightness-removing column to remove the ICCP, and recovering the adiponitrile in the second light component impurities.
A step of removing the weight:
the adiponitrile solution (containing heavy component impurities) discharged from the bottom of the second light component removal tower enters the middle lower part of the heavy component removal tower, the reflux ratio of the heavy component removal tower is controlled to be 2.0, the temperature at the top of the tower is controlled to be 160 ℃, and the pressure is 15 mmHg; the bottom temperature was 178 ℃ and the pressure was 40 mmHg. Most of gas-phase adiponitrile discharged from the top of the de-heavy tower is condensed and then circulates to the top of the de-heavy tower to control the temperature of the top of the tower, and the rest is condensed again to 30-50 ℃ to obtain an adiponitrile product, wherein the adiponitrile content in the adiponitrile product is 99.92% through detection; ICCP content 120 ppm; the VATP (2-amyl-4-amino-5, 6-trimethylenepyrimidine) content is 300 ppm;
adiponitrile containing heavy component impurities and discharged from the bottom of the de-heavy tower enters an evaporator, and is evaporated at 190 ℃ under 60mmHg to obtain adiponitrile gas phase with low content of the heavy component impurities and evaporation residual liquid; the adiponitrile gas phase with low content of heavy component impurities is condensed and then circulated back to the de-heavy tower to recover adiponitrile, and the evaporation residual liquid is discharged to a separation tower to recover the residual adiponitrile.
Comparative example 1
This comparative example provides a method for refining adiponitrile, using an apparatus similar to that of fig. 2 except that the apparatus used in this comparative example does not include a de-ketonizer, a de-ketonizer reboiler, a de-ketonizer condenser, and a vacuum pump communicating with the de-ketonizer condenser; the method comprises the following steps:
the crude product which is mainly adiponitrile and is obtained by the reaction of adipic acid and ammonia is the crude product of adiponitrile. Through detection, the content of each component in the crude product is as follows: adiponitrile 89.5%, water 7.68%, cyclopentanone 0.38%, ICCP about 0.38%, ammonia 0.32%, and other light components 0.05%, and heavy components (including 5-cyanovaleramide, 5-cyanovaleric acid, adiponitrile dimer, etc.) about 1.69% (of which 5-cyanovaleramide is 1.35%).
And (3) light component removal:
feeding the crude nitrile solution into the middle upper part of a lightness-removing column, controlling the temperature at the top of the lightness-removing column to be 150 ℃ and the pressure to be 10 mmHg; condensing light component impurities discharged from the top of the light component removal tower to 100 ℃, and then partially circulating the light component impurities to the top of the light component removal tower for controlling the temperature of the top of the light component removal tower; and the rest part is subjected to ICCP crystallization, and the filtrate after filtering off ICCP crystals is returned to the crude adiponitrile storage tank to be mixed with crude adiponitrile, and is circulated to the light component removal tower to recover adiponitrile therein.
The temperature of the bottom of the light component removal tower is controlled at 215 ℃; the pressure is 80 mmHg;
a step of removing the weight:
the adiponitrile solution discharged from the bottom of the light component removal tower is sent to the middle lower part of the heavy component removal tower, the reflux ratio of the heavy component removal tower is controlled to be 1.65, the temperature at the top of the tower is controlled to be 155 ℃, and the pressure is 10 mmHg; the bottom pressure was 58mmHg and the temperature was controlled to 204 ℃. After condensing the gas-phase adiponitrile discharged from the top of the de-heavy tower, partially circulating the gas-phase adiponitrile to the top of the de-heavy tower to control the temperature of the top of the de-heavy tower, and re-condensing the rest part to 30-50 ℃ to obtain an adiponitrile product, wherein the adiponitrile content in the adiponitrile product is 99.7% through detection; ICCP content was 880 ppm; the VATP (2-amyl-4-amino-5, 6-trimethylenepyrimidine) content is 1450 ppm;
evaporating adiponitrile solution containing heavy component impurities discharged from the bottom of the de-heavy tower at 154 ℃ under 10mmHg to obtain adiponitrile gas phase containing the heavy component impurities and heavy residual liquid; and condensing the adiponitrile gas phase containing heavy component impurities, circulating the gas phase to the bottom of the de-weighting tower to recover adiponitrile, and sending the evaporated residual liquid to a separation tower of the reaction part to recover residual adiponitrile.
It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.
Claims (13)
1. A method for refining adiponitrile is characterized by comprising the step of removing cyclopentanone in crude adiponitrile.
2. The method for refining adiponitrile according to claim 1, wherein an azeotrope of cyclopentanone and water is separated from the crude adiponitrile to achieve cyclopentanone removal.
3. The method for refining adiponitrile according to claim 1 or 2, wherein the removal of cyclopentanone is carried out by using a de-ketonizer, and the bottom temperature of the de-ketonizer is controlled to be 140-;
the de-ketonizing tower is a filler rectifying tower.
4. The method for refining adiponitrile according to claim 3, wherein said top pressure of said ketone-removing column is 100-200mmHg and the temperature at the top of said column is controlled to 40-60 ℃.
5. The method of refining adiponitrile according to claim 4, wherein said de-ketonizer has a reflux ratio of 1 to 3.
6. A method for refining adiponitrile according to any one of claims 1 to 5, wherein said method further comprises subjecting the crude adiponitrile from which cyclopentanone has been removed to a light ends removal treatment by means of a packed light ends removal column, wherein the temperature at the bottom of said packed light ends removal column is controlled to 160-195 ℃ and the pressure at the bottom of said packed light ends removal column is 20-65mmHg, the temperature at the top of said packed light ends removal column is controlled to 140-180 ℃ and the pressure at the top of said packed light ends removal column is 5-50 mmHg.
7. The method for refining adiponitrile according to claim 6, wherein said method further comprises the step of removing the weight of the crude adiponitrile after the light ends removal treatment, wherein said weight removal treatment is carried out by using a packed weight removal column, the temperature at the bottom of said weight removal column is controlled to 160-195 ℃, the pressure at the bottom of said column is controlled to 20-65mmHg, the temperature at the top of said column is controlled to 150-180 ℃, and the pressure at the top of said column is controlled to 10-50 mmHg.
8. The method of refining adiponitrile according to claim 7, wherein said de-heavy column has a reflux ratio of 0.8 to 3.0.
9. A refining process of adiponitrile as recited in claim 7 or 8, wherein before the weight removal treatment of the crude adiponitrile subjected to the weight removal treatment, the method further comprises subjecting the crude adiponitrile subjected to the weight removal treatment to a secondary weight removal treatment, wherein the secondary weight removal treatment is carried out by using a second packed weight removal column, the temperature at the bottom of the second packed weight removal column is controlled to 160-195 ℃, the pressure at the bottom of the second packed weight removal column is controlled to 20-65mmHg, the temperature at the top of the second packed weight removal column is controlled to 140-180 ℃, and the pressure at the top of the second packed weight removal column is controlled to 10-50 mmHg.
10. The method for refining adiponitrile according to claim 7 or 8, wherein the removed cyclopentanone is partially recycled to the top of the de-ketonizer column after being condensed for controlling the temperature of the top of the de-ketonizer column;
and/or condensing light component impurities obtained by separation at the top of the filler light component removal tower, then partially circulating the condensed light component impurities to the top of the filler light component removal tower for controlling the temperature at the top of the tower, and crystallizing and filtering the rest of the condensed light component impurities to obtain filtrate, and circulating the filtrate to the filler light component removal tower;
and/or condensing adiponitrile separated from the top of the filler de-weighting tower, then circulating part of the adiponitrile into the filler de-weighting tower for controlling the temperature at the top of the de-filler de-weighting tower, and cooling the rest part of the adiponitrile to obtain the adiponitrile product.
11. An apparatus for refining adiponitrile, comprising,
the de-ketonizing device comprises an adiponitrile crude product inlet, a cyclopentanone-containing impurity outlet and a crude adiponitrile outlet;
the de-lightening device comprises a crude adiponitrile inlet and an adiponitrile solution outlet, and the crude adiponitrile inlet is communicated with the crude adiponitrile outlet of the de-ketonizer;
the de-weighting device comprises an adiponitrile outlet and an adiponitrile solution inlet, and the adiponitrile solution inlet is communicated with the adiponitrile solution outlet of the de-weighting device.
12. The adiponitrile refining apparatus according to claim 11, wherein the de-ketonizer is a packed rectifying column.
13. The adiponitrile refining apparatus according to claim 11 or 12, wherein the lightness-removing means comprises 1 or 2 packed lightness-removing columns;
when the light component removal device comprises 1 packed light component removal tower, the adiponitrile solution outlet of the packed light component removal tower is communicated with the adiponitrile solution inlet of the heavy component removal device;
when the lightness-removing device comprises 2 packed lightness-removing columns, the lightness-removing device comprises a first packed lightness-removing column and a second packed lightness-removing column; an adiponitrile solution outlet of the first packing lightness-removing tower is communicated with an adiponitrile solution inlet at the top of the second packing lightness-removing tower, and a bottom outlet of the second packing lightness-removing tower is communicated with an adiponitrile solution inlet of the weight removal device.
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| DE857048C (en) * | 1941-03-19 | 1952-11-27 | Basf Ag | Process for the catalytic production of carboxylic acid dinitriles |
| DE857194C (en) * | 1942-12-19 | 1952-11-27 | Basf Ag | Process for the preparation of dinitriles from aliphatic ª ‡, ªÏ-dicarboxylic acids |
| GB731458A (en) * | 1951-12-06 | 1955-06-08 | Basf Ag | Improvements in the production of pure adipic acid dinitrile |
| US3299116A (en) * | 1963-02-20 | 1967-01-17 | Rhodiatoce | Continuous process for producing adiponitrile |
| US3325532A (en) * | 1963-08-15 | 1967-06-13 | Ici Ltd | Manufacture of adiponitrile |
| US3451900A (en) * | 1966-06-14 | 1969-06-24 | Vickers Zimmer Ag | Adiponitrile recovery by multistage vacuum distillation |
| GB1354565A (en) * | 1970-06-24 | 1974-06-05 | Rhone Poulenc Sa | Process for the purification of adiponitrile |
| CN1031368A (en) * | 1988-03-26 | 1989-03-01 | 高云清 | From the heavy constituent of adiponitrile synthesizer discharging, extract the method for adiponitrile etc. |
| US5228956A (en) * | 1992-10-02 | 1993-07-20 | Lloyd Berg | Separation of 3-pentanone from formic acid by extractive distillation |
| CN108409606A (en) * | 2018-06-01 | 2018-08-17 | 重庆华峰化工有限公司 | A kind of production system of adiponitrile |
| CN108467351A (en) * | 2018-06-01 | 2018-08-31 | 重庆华峰化工有限公司 | A kind of adiponitrile refining system |
| CN108484442A (en) * | 2018-06-01 | 2018-09-04 | 重庆华峰化工有限公司 | A kind of process for purification of adiponitrile |
| CN208471947U (en) * | 2018-06-01 | 2019-02-05 | 重庆华峰化工有限公司 | A kind of adiponitrile refining system |
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