CN111471015B - Device and method for recycling caprolactam in benzene distillation residual liquid - Google Patents
Device and method for recycling caprolactam in benzene distillation residual liquid Download PDFInfo
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- CN111471015B CN111471015B CN201910084455.9A CN201910084455A CN111471015B CN 111471015 B CN111471015 B CN 111471015B CN 201910084455 A CN201910084455 A CN 201910084455A CN 111471015 B CN111471015 B CN 111471015B
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- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 title claims abstract description 177
- JBKVHLHDHHXQEQ-UHFFFAOYSA-N epsilon-caprolactam Chemical compound O=C1CCCCCN1 JBKVHLHDHHXQEQ-UHFFFAOYSA-N 0.000 title claims abstract description 102
- 239000007788 liquid Substances 0.000 title claims abstract description 60
- 238000004821 distillation Methods 0.000 title claims abstract description 49
- 238000000034 method Methods 0.000 title claims abstract description 42
- 238000004064 recycling Methods 0.000 title abstract description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 65
- 230000008569 process Effects 0.000 claims abstract description 30
- 239000012535 impurity Substances 0.000 claims abstract description 20
- 238000000926 separation method Methods 0.000 claims abstract description 19
- AWSFEOSAIZJXLG-UHFFFAOYSA-N azepan-2-one;hydrate Chemical compound O.O=C1CCCCCN1 AWSFEOSAIZJXLG-UHFFFAOYSA-N 0.000 claims abstract description 12
- 239000007791 liquid phase Substances 0.000 claims abstract description 10
- 238000004519 manufacturing process Methods 0.000 claims abstract description 8
- 238000006386 neutralization reaction Methods 0.000 claims abstract description 8
- 230000008707 rearrangement Effects 0.000 claims abstract description 8
- 239000000243 solution Substances 0.000 claims description 19
- 230000003068 static effect Effects 0.000 claims description 15
- 238000002156 mixing Methods 0.000 claims description 12
- 239000002994 raw material Substances 0.000 claims description 7
- 150000002402 hexoses Chemical class 0.000 claims description 4
- 239000011259 mixed solution Substances 0.000 claims description 3
- 238000009413 insulation Methods 0.000 abstract description 6
- 239000000463 material Substances 0.000 abstract description 6
- 238000010992 reflux Methods 0.000 abstract description 2
- 239000012071 phase Substances 0.000 description 10
- 239000007864 aqueous solution Substances 0.000 description 6
- 239000012074 organic phase Substances 0.000 description 6
- 238000000605 extraction Methods 0.000 description 5
- 229920002292 Nylon 6 Polymers 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 239000008346 aqueous phase Substances 0.000 description 3
- 238000002425 crystallisation Methods 0.000 description 3
- 230000008025 crystallization Effects 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 238000011084 recovery Methods 0.000 description 3
- PAYRUJLWNCNPSJ-UHFFFAOYSA-N Aniline Chemical compound NC1=CC=CC=C1 PAYRUJLWNCNPSJ-UHFFFAOYSA-N 0.000 description 2
- YLQBMQCUIZJEEH-UHFFFAOYSA-N Furan Chemical compound C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 238000001704 evaporation Methods 0.000 description 2
- 238000006116 polymerization reaction Methods 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 238000004321 preservation Methods 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 238000007670 refining Methods 0.000 description 2
- 239000007790 solid phase Substances 0.000 description 2
- 239000004094 surface-active agent Substances 0.000 description 2
- 229920002994 synthetic fiber Polymers 0.000 description 2
- 239000012209 synthetic fiber Substances 0.000 description 2
- VEPOHXYIFQMVHW-XOZOLZJESA-N 2,3-dihydroxybutanedioic acid (2S,3S)-3,4-dimethyl-2-phenylmorpholine Chemical compound OC(C(O)C(O)=O)C(O)=O.C[C@H]1[C@@H](OCCN1C)c1ccccc1 VEPOHXYIFQMVHW-XOZOLZJESA-N 0.000 description 1
- 229920006052 Chinlon® Polymers 0.000 description 1
- 239000004677 Nylon Substances 0.000 description 1
- PCNDJXKNXGMECE-UHFFFAOYSA-N Phenazine Natural products C1=CC=CC2=NC3=CC=CC=C3N=C21 PCNDJXKNXGMECE-UHFFFAOYSA-N 0.000 description 1
- 239000004952 Polyamide Substances 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 150000001408 amides Chemical class 0.000 description 1
- 150000004982 aromatic amines Chemical group 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 238000005119 centrifugation Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 239000012043 crude product Substances 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000004945 emulsification Methods 0.000 description 1
- 229920006351 engineering plastic Polymers 0.000 description 1
- 239000003344 environmental pollutant Substances 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000012847 fine chemical Substances 0.000 description 1
- 238000005984 hydrogenation reaction Methods 0.000 description 1
- 230000002209 hydrophobic effect Effects 0.000 description 1
- 238000005342 ion exchange Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- -1 ketoxime Chemical compound 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229920001778 nylon Polymers 0.000 description 1
- 231100000719 pollutant Toxicity 0.000 description 1
- 229920002647 polyamide Polymers 0.000 description 1
- 230000008929 regeneration Effects 0.000 description 1
- 238000011069 regeneration method Methods 0.000 description 1
- 230000037390 scarring Effects 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 238000013517 stratification Methods 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D223/00—Heterocyclic compounds containing seven-membered rings having one nitrogen atom as the only ring hetero atom
- C07D223/02—Heterocyclic compounds containing seven-membered rings having one nitrogen atom as the only ring hetero atom not condensed with other rings
- C07D223/06—Heterocyclic compounds containing seven-membered rings having one nitrogen atom as the only ring hetero atom not condensed with other rings with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
- C07D223/08—Oxygen atoms
- C07D223/10—Oxygen atoms attached in position 2
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D201/00—Preparation, separation, purification or stabilisation of unsubstituted lactams
- C07D201/16—Separation or purification
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)
Abstract
The invention discloses a device and a method for recycling caprolactam in benzene distillation residual liquid, which are characterized in that under the condition of closed heat insulation, the benzene distillation residual liquid is mixed with water, the mixed liquid enters a coarse separation device to obtain a water-containing solution a and residual liquid b, the residual liquid b enters an oil-water separator to obtain a water-containing solution c and residual liquid d, the water-containing solution a and the water-containing solution c return to a neutralization process of a liquid phase rearrangement unit in caprolactam production, and the residual liquid d is subjected to incineration treatment after benzene is recycled by distillation. The invention has simple process flow, high caprolactam yield, caprolactam content in the residual liquid d not higher than 1%, and impurity content of the caprolactam-water solution carrying reflux not higher than 30% of impurities in the benzene distillation residual liquid; besides various material liquid conveying pumps, the process of the invention has no moving equipment and simple and reliable device.
Description
Technical Field
The invention belongs to the field of fine chemical industry, and relates to a device and a method for recovering caprolactam in benzene distillation residual liquid.
Background
Caprolactam (CPL) is one of important organic chemical raw materials, and is mainly used for producing nylon 6 engineering plastics and synthetic fiber nylon 6 (chinlon). When used as a polymerization raw material for nylon 6, the quality requirements are very strict. Particularly, the existence of impurities in caprolactam, although the content is very small, has a great influence on the quality of a finished product of caprolactam, and can seriously influence the quality of synthetic fibers. For example, reducing impurities such as aniline, ketoxime, furan, phenazine, alcohols contained in caprolactam can lead to a decrease in PM value and stability of caprolactam; impurities with chromophore groups such as aromatic amines can cause the color chromaticity of caprolactam to increase and the transparency to decrease; while some basic substances can raise the volatile base of caprolactam. When these trace amounts of chemical impurities are contained, the polyamide is formed, which reduces various properties such as tensile strength and heat resistance of the fiber, and when iron is contained, caprolactam is yellow, and chain formation during polymerization is affected, which causes polycaprolactam to become brittle.
The crude product amide is subjected to the procedures of extraction, back extraction, ion exchange, hydrogenation, evaporation concentration, distillation and the like to obtain the finished product caprolactam which contains almost no impurities. Wherein the crude benzene phase after back extraction is evaporated to recover benzene, and the heavy impurities in the tower bottom are called benzene distillation residual liquid, wherein the components comprise benzene to 20 percent, caprolactam to 70 percent, water and other byproducts to 10 percent by mass percent respectively. The traditional treatment method of benzene distillation raffinate is to concentrate and burn, and a large amount of NO is produced during burning X Not only increases the load of the incinerator and the concentration of the pollutant discharged by the tail gas, but also causes corrosion of the inside of the device equipment; not only a large amount of caprolactam is lost, but also more environmental pollution is caused.
In CN1371906A, a method for recovering caprolactam from benzene distillation residual liquid is disclosed, wherein 90-95% of caprolactam crystals are obtained by adopting a mode of cooling crystallization and centrifugation after further concentration of the benzene distillation residual liquid, and more than 99% of caprolactam is obtained by further distillation. The caprolactam which can be directly used for preparing MC nylon is recovered by the method, but the process of the caprolactam comprises cooling crystallization, so that the problem of equipment scarring in the crystallization process cannot be avoided in actual operation, and the industrial continuous recovery cost is high.
CN104326982a also refers to a method for recovering caprolactam from benzene raffinate, wherein benzene raffinate and water are fed into a centrifugal extractor respectively, then surfactant is added, and the mixture is extracted and separated under the action of the centrifugal extractor. The addition of the surfactants mentioned in this patent is intended to reduce the amount of dissolved impurities in the aqueous phase after extraction, but it is inevitable that new impurities are introduced, which is disadvantageous for further refining of caprolactam.
In CN104817422a, an extraction tower is used to contact and separate the benzene distillation residue from water, in practice, after the benzene distillation residue is mixed with water, the volume of the organic phase is reduced to less than 20%, and if there is no suitable separation structure, the mixture will form serious emulsification, so that the organic phase and the water phase are difficult to separate or the separation speed is extremely slow. In addition, the adsorption process mentioned in the patent will generate a large amount of waste liquid in the regeneration process, thus causing secondary pollution.
Disclosure of Invention
In order to solve the problems in the prior art, the invention aims to provide a simple and efficient method for recovering caprolactam in benzene distillation residual liquid, wherein the recovery rate of caprolactam in the benzene distillation residual liquid after treatment is not lower than 95 percent, and the carried impurity content is not higher than 30 weight percent of the impurity content in the benzene distillation residual liquid.
In order to achieve the aim, the invention provides a method for recovering caprolactam in benzene distillation residual liquid, which comprises the steps of mixing benzene distillation residual liquid with water according to a weight ratio of 1:10-3:1 under the condition of airtight heat insulation, and feeding the mixed liquid into a coarse separation device to obtain a water solution a and a residual liquid b.
The closed heat insulation refers to that after the benzene distillation residual liquid is discharged from the tower bottom of the benzene distillation tower, the benzene distillation residual liquid is kept in a closed heat insulation environment without heat exchange and is conveyed to be mixed with water. The simplest mode of the invention is that two different material pipelines are converged into one pipeline for mixing, thus under the condition of pipeline heat preservation, a closed heat insulation environment can be almost realized, and the problem that residual benzene volatilizes due to severe temperature change, so that excessive impurities are dissolved in water after mixing, or benzene distillation residual liquid forms a solid-liquid phase due to caprolactam precipitation, which is unfavorable for conveying is avoided. Other modes of material meeting are sufficient to form an adiabatic environment.
Preferably, the weight ratio of the benzene distillation residual liquid to the water is 1:2-2:1.
Preferably, the water is derived from water at the top of a caprolactam refining and evaporating unit or fresh process water.
Preferably, the mixing of the benzene raffinate and water is accomplished in a static mixer, and after mixing in an adiabatic environment, the mixed liquor is not homogeneous, but does not exhibit a gas phase or a solid phase, so the static mixer is selected so long as sufficient radial liquid-liquid circulation mixing can be achieved, including but not limited to SV, SK, SH, SX, SL static mixers.
Preferably, the benzene raffinate is mixed with water for a residence time of at least 0.01 hours, preferably from 0.1 to 0.3 hours.
Preferably, the crude separator is a crude separator having a coalescer structure therein. The invention utilizes the low solubility of the water phase and the organic phase and the different density to separate liquid from liquid under the condition of no mechanical power and heat exchange, and the lipophilic and hydrophobic effects of the surface of the coalescer to coalesce the tiny oil drops, thereby accelerating the separation of the organic phase and the water phase. The bulk structure of the coarse separator may be a tank, a tower, or other structure, as long as it is closed, pressure resistant, and capable of containing a coalescer therein.
Preferably, the residence time of the mixed liquor in the coarse separator is at least 0.5h, preferably 0.5 to 3h.
Preferably, the operating pressure of the crude separator is 0.01 to 1.0Mpa, preferably 0.2 to 0.9Mpa. The pressure of the separation process of the mixed solution in the coarse separator is maintained to be capable of meeting the requirement that the aqueous solution a and the residual liquid b of the coarse separator can enter the next process; too high a pressure may lead to an unnecessary increase in the solubility of the raffinate b in the aqueous solution a, thereby bringing in a large amount of impurities.
Preferably, the operating temperature of the crude separator is from 0 to 70 ℃, preferably from 20 to 45 ℃.
Preferably, the raffinate b enters an oil-water separator to obtain a hexose solution c and a raffinate d, the hexose solution c returns to a neutralization process of a liquid phase rearrangement unit for caprolactam production, and the raffinate d is subjected to incineration treatment after benzene is distilled and recovered.
Preferably, the number of the oil-water separators is at least one, and when the number of the oil-water separators is two or more, the residual liquid b sequentially enters the oil-water separators to carry out multistage separation.
Preferably, the oil-water separator is a tower, a tank or an oil-water separator working under dynamic state for layering organic phase and water phase under static state, and preferably, the oil-water separator is used, so that separation with small occupied area and high efficiency can be realized.
Preferably, the residence time of the raffinate b in the oil-water separator is at least 1h, preferably from 2 to 4h.
Preferably, when a column or tank is used for the stratification of the organic phase and the aqueous phase with standing, the process is operated at a pressure of 0.01 to 1.0Mpa, preferably 0.2 to 0.9Mpa.
Preferably, the caprolactam content in the raffinate d is not higher than 1wt%, and the impurity content in the aqueous solution a and the aqueous solution c is not higher than 30wt% of the impurity content in the benzene distillation raffinate.
The invention also provides a device for recovering caprolactam in benzene distillation residual liquid, which comprises a water delivery pump, a raw material delivery pump connected to a benzene distillation tower kettle, a static mixer connected to the raw material delivery pump and the water delivery pump, a coarse separator connected to the static mixer, a residual liquid delivery pump connected to an outlet at the upper part of the coarse separator, and a caprolactam-water solution storage tank connected to an outlet at the lower part of the coarse separator.
Preferably, the device further comprises an oil-water separator connected with an upper outlet of the coarse separator and a residual liquid conveying pump, wherein the residual liquid conveying pump is connected with an upper outlet of the oil-water separator, and the caprolactam-water solution storage tank is connected with a lower outlet of the oil-water separator.
More preferably, the number of the oil-water separators is at least one, and when the number of the oil separators is two or more, the oil-water separators are sequentially connected in series for multistage separation.
Preferably, the outlet of the caprolactam-water solution storage tank is connected with a discharge pump, and the discharge pump is used for returning the caprolactam-water solution to the neutralization process of the liquid phase rearrangement unit for caprolactam production.
The invention has the beneficial effects that:
the invention utilizes the benzene distillation raffinate of the tower bottom liquid of the benzene distillation tower to be fully mixed with water under the condition of heat insulation and airtight, and then carries out one-step or multi-step separation so as to realize the recycling of caprolactam-water solution. After treatment, the caprolactam-water solution is returned to the neutralization process of the liquid phase rearrangement unit for caprolactam production for recycling, and residual liquid of the benzene distillation residual liquid is burned after benzene distillation; besides various material liquid conveying pumps, the process of the invention has no moving equipment and simple and reliable device.
Drawings
FIG. 1 is a process flow diagram of the present invention;
1, a water delivery pump; 2. a raw material delivery pump; 3. a static mixer; 4. a coarse separator; 5. an oil-water separator; 6. a raffinate transfer pump; 7. a caprolactam-water solution storage tank; 8. and a discharging pump.
Detailed Description
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The invention may be embodied in many other forms than described herein and similarly modified by those skilled in the art without departing from the spirit or scope of the invention, which is therefore not limited to the specific embodiments disclosed below.
The benzene distillation residual liquid is contacted with water before entering the static mixer in the simplest mode, two different material pipelines are converged into one pipeline which goes to the static mixer, so that under the condition of heat preservation of the pipeline, a closed heat-insulating environment can be almost realized, the volatilization of residual benzene caused by severe temperature change is avoided, excessive impurities are dissolved in water after mixing, or the benzene distillation residual liquid is formed into a solid-liquid phase by precipitation of caprolactam, which is unfavorable for conveying. Other modes of material meeting are sufficient to form an adiabatic environment.
After mixing in an adiabatic environment, the mixture is not homogeneous, but does not appear in the gas phase or solid phase, so the static mixer is selected so long as adequate mixing is achieved. The temperature after mixing is determined by the temperature before mixing the water and the benzene distillation residue, the amount of substances and the heat capacity of each, and an additional heat exchanger is not needed to adjust the temperature of the mixed solution.
The bulk separator for coarse separation of the mixed liquor may be tank, tower or other structure, so long as it is airtight, pressure-proof and capable of holding a coalescer.
The pressure of the separation process carried out in the mixed liquor coarse separator is maintained to be capable of meeting the requirement that the water phase and the oil phase of the coarse separator can enter the next process; too high a pressure may result in an unnecessary increase in the solubility of the oil phase in the aqueous phase.
The oil-water separator for further separating the upper residual liquid b is preferably an oil-water separator, so that the separation of a small amount of water in the oil with small occupied area and high efficiency can be realized.
The following are specific examples.
And (3) respectively conveying benzene distillation residual liquid and water to an inlet of a static mixer by using a pump at different flow rates, conveying the mixed liquid into a coarse separation device, returning the separated aqueous solution a to a neutralization process of a liquid phase rearrangement unit for caprolactam production, separating residual liquid b again by using an oil-water separator, returning the obtained aqueous solution c to a neutralization process of the liquid phase rearrangement unit for caprolactam production, and finally recycling benzene from the residual liquid d and carrying out incineration treatment. Several sets of different conditions are listed below to illustrate the patent case.
During the experiment, the selection of the type of static mixer, the type of coalescer, the type of coarse separator and the type of oil-water separator, under the similar process conditions as the above examples, the numerical fluctuation range of caprolactam recovery rate and impurity reflux rate is basically within 0.1-0.5%, and the realization of the process is not affected.
The above examples and comparative examples only represent a few embodiments of the present invention, which are described in more detail and detail, but are not to be construed as limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention.
Claims (7)
1. A process for recovering caprolactam from benzene distillation residues, characterized in that: under the airtight and adiabatic condition, mixing benzene distillation residual liquid and water according to the weight ratio of 1:10-3:1, and enabling the mixed liquid to enter a coarse separation device to obtain a water solution a and residual liquid b; the crude separator is a crude separator internally provided with a coalescer structure; the residence time of the mixed solution in the coarse separation separator is at least 0.5h, the operation pressure of the coarse separation separator is 0.01-1.0 Mpa, and the operation temperature is 0-70 ℃;
the benzene distillation residual liquid and water are mixed in a static mixer, and the residence time is at least 0.01h;
the residence time of the residual liquid b in the oil-water separator is at least 1h, and the process operating pressure is 0.01-1.0 Mpa;
the residual liquid b enters an oil-water separator to obtain a hexose solution c and a residual liquid d, the hexose solution c returns to a neutralization process of a liquid phase rearrangement unit for caprolactam production, and the residual liquid d is subjected to incineration treatment after benzene is distilled and recovered;
the method for recovering caprolactam in benzene distillation residual liquid is realized by a device which comprises a water conveying pump, a raw material conveying pump connected with a benzene distillation tower kettle, a static mixer connected with the raw material conveying pump and the water conveying pump, a coarse separator connected with the static mixer, a residual liquid conveying pump connected with an outlet at the upper part of the coarse separator and a caprolactam-water solution storage tank connected with an outlet at the lower part of the coarse separator.
2. A process for recovering caprolactam from a benzene distillation residual according to claim 1, wherein: the weight ratio of the benzene distillation residual liquid to the water is 1:2-2:1.
3. A process for recovering caprolactam from a benzene distillation residual according to claim 1, wherein: and when the number of the oil-water separators is two or more, the residual liquid b sequentially enters the oil-water separators to carry out multistage separation.
4. A process for recovering caprolactam from a benzene distillation residual according to claim 1, wherein: the caprolactam content in the raffinate d is not higher than 1wt%, and the impurity content in the aqueous caprae seu solution a and the aqueous caprae seu solution c is not higher than 30wt% of the impurity content in the benzene distillation raffinate.
5. A process for recovering caprolactam from a benzene distillation residual according to claim 1, wherein: the device also comprises an oil-water separator connected with the upper outlet of the coarse separator and a raffinate conveying pump, wherein the raffinate conveying pump is connected with the upper outlet of the oil-water separator, and the caprolactam-water solution storage tank is connected with the lower outlet of the oil-water separator.
6. The process for recovering caprolactam from a benzene distillation residual according to claim 5, wherein: and when the oil separator is provided with two or more than two oil separators, the oil separators are sequentially connected in series for multistage separation.
7. A process for recovering caprolactam from a benzene distillation residual according to claim 1, wherein: and the outlet of the caprolactam-water solution storage tank is connected with a discharge pump, and the discharge pump is used for returning the caprolactam-water solution to the neutralization process of the liquid phase rearrangement unit for caprolactam production.
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| CN201910084455.9A CN111471015B (en) | 2019-01-24 | 2019-01-24 | Device and method for recycling caprolactam in benzene distillation residual liquid |
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| CN201910084455.9A CN111471015B (en) | 2019-01-24 | 2019-01-24 | Device and method for recycling caprolactam in benzene distillation residual liquid |
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| CN111471015B true CN111471015B (en) | 2024-01-30 |
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1998049140A1 (en) * | 1997-04-29 | 1998-11-05 | Dsm N.V. | Process for recovering caprolactam from a neutralized rearrangement mixture |
| CN103539738A (en) * | 2013-11-01 | 2014-01-29 | 华东理工大学 | Method and device for recovering caprolactam in benzene distillation residue |
-
2019
- 2019-01-24 CN CN201910084455.9A patent/CN111471015B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1998049140A1 (en) * | 1997-04-29 | 1998-11-05 | Dsm N.V. | Process for recovering caprolactam from a neutralized rearrangement mixture |
| CN103539738A (en) * | 2013-11-01 | 2014-01-29 | 华东理工大学 | Method and device for recovering caprolactam in benzene distillation residue |
| CN104326982A (en) * | 2013-11-01 | 2015-02-04 | 华东理工大学 | Method and device for recycling caprolactam in benzene distillation residual liquid |
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| CN111471015A (en) | 2020-07-31 |
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