CN214422544U - Device for producing hexamethylene diamine from caprolactam - Google Patents
Device for producing hexamethylene diamine from caprolactam Download PDFInfo
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- CN214422544U CN214422544U CN202120367206.3U CN202120367206U CN214422544U CN 214422544 U CN214422544 U CN 214422544U CN 202120367206 U CN202120367206 U CN 202120367206U CN 214422544 U CN214422544 U CN 214422544U
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- JBKVHLHDHHXQEQ-UHFFFAOYSA-N epsilon-caprolactam Chemical compound O=C1CCCCCN1 JBKVHLHDHHXQEQ-UHFFFAOYSA-N 0.000 title claims abstract description 328
- NAQMVNRVTILPCV-UHFFFAOYSA-N hexane-1,6-diamine Chemical compound NCCCCCCN NAQMVNRVTILPCV-UHFFFAOYSA-N 0.000 title claims abstract description 300
- 238000006297 dehydration reaction Methods 0.000 claims abstract description 92
- 238000005984 hydrogenation reaction Methods 0.000 claims abstract description 70
- 230000018044 dehydration Effects 0.000 claims abstract description 67
- 239000012071 phase Substances 0.000 claims abstract description 53
- 239000007791 liquid phase Substances 0.000 claims abstract description 29
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims abstract description 24
- 239000012295 chemical reaction liquid Substances 0.000 claims abstract description 9
- 239000002351 wastewater Substances 0.000 claims abstract description 8
- 238000007599 discharging Methods 0.000 claims abstract description 5
- 239000007789 gas Substances 0.000 claims description 45
- 239000003054 catalyst Substances 0.000 claims description 43
- 238000006243 chemical reaction Methods 0.000 claims description 41
- 239000007788 liquid Substances 0.000 claims description 36
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 35
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 34
- 239000001257 hydrogen Substances 0.000 claims description 34
- 229910052739 hydrogen Inorganic materials 0.000 claims description 34
- 239000007787 solid Substances 0.000 claims description 24
- 239000000463 material Substances 0.000 claims description 19
- 239000002904 solvent Substances 0.000 claims description 12
- 238000005406 washing Methods 0.000 claims description 8
- SYECJBOWSGTPLU-UHFFFAOYSA-N hexane-1,1-diamine Chemical compound CCCCCC(N)N SYECJBOWSGTPLU-UHFFFAOYSA-N 0.000 claims description 6
- 239000002699 waste material Substances 0.000 claims description 3
- 238000000926 separation method Methods 0.000 abstract description 12
- 239000003085 diluting agent Substances 0.000 abstract description 8
- 239000000126 substance Substances 0.000 abstract description 6
- AWSFEOSAIZJXLG-UHFFFAOYSA-N azepan-2-one;hydrate Chemical compound O.O=C1CCCCCN1 AWSFEOSAIZJXLG-UHFFFAOYSA-N 0.000 abstract description 5
- 238000005265 energy consumption Methods 0.000 abstract description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical group [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 60
- 239000000203 mixture Substances 0.000 description 51
- KBMSFJFLSXLIDJ-UHFFFAOYSA-N 6-aminohexanenitrile Chemical compound NCCCCCC#N KBMSFJFLSXLIDJ-UHFFFAOYSA-N 0.000 description 44
- 239000000243 solution Substances 0.000 description 27
- 238000009833 condensation Methods 0.000 description 26
- 230000005494 condensation Effects 0.000 description 26
- 239000000047 product Substances 0.000 description 21
- 238000000034 method Methods 0.000 description 19
- GODRGSBJTFNCPC-UHFFFAOYSA-N n'-ethylhexane-1,6-diamine Chemical compound CCNCCCCCCN GODRGSBJTFNCPC-UHFFFAOYSA-N 0.000 description 15
- 239000002994 raw material Substances 0.000 description 14
- 238000001816 cooling Methods 0.000 description 13
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 12
- 238000004519 manufacturing process Methods 0.000 description 12
- 238000004176 ammonification Methods 0.000 description 10
- 238000002156 mixing Methods 0.000 description 9
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 7
- 238000001704 evaporation Methods 0.000 description 7
- YMHQVDAATAEZLO-UHFFFAOYSA-N cyclohexane-1,1-diamine Chemical compound NC1(N)CCCCC1 YMHQVDAATAEZLO-UHFFFAOYSA-N 0.000 description 6
- 239000006227 byproduct Substances 0.000 description 5
- 239000007795 chemical reaction product Substances 0.000 description 5
- 239000007868 Raney catalyst Substances 0.000 description 4
- 229910000564 Raney nickel Inorganic materials 0.000 description 4
- 229910021529 ammonia Inorganic materials 0.000 description 4
- 238000009903 catalytic hydrogenation reaction Methods 0.000 description 4
- GVALZJMUIHGIMD-UHFFFAOYSA-H magnesium phosphate Chemical compound [Mg+2].[Mg+2].[Mg+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O GVALZJMUIHGIMD-UHFFFAOYSA-H 0.000 description 4
- 239000004137 magnesium phosphate Substances 0.000 description 4
- 229910000157 magnesium phosphate Inorganic materials 0.000 description 4
- 229960002261 magnesium phosphate Drugs 0.000 description 4
- 235000010994 magnesium phosphates Nutrition 0.000 description 4
- 229920001778 nylon Polymers 0.000 description 4
- 238000005086 pumping Methods 0.000 description 4
- 238000004064 recycling Methods 0.000 description 4
- 238000011268 retreatment Methods 0.000 description 4
- 238000003756 stirring Methods 0.000 description 4
- 238000003860 storage Methods 0.000 description 4
- 239000004677 Nylon Substances 0.000 description 3
- 125000004122 cyclic group Chemical group 0.000 description 3
- 125000002924 primary amino group Chemical group [H]N([H])* 0.000 description 3
- 125000006239 protecting group Chemical group 0.000 description 3
- SLXKOJJOQWFEFD-UHFFFAOYSA-N 6-aminohexanoic acid Chemical compound NCCCCCC(O)=O SLXKOJJOQWFEFD-UHFFFAOYSA-N 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- 239000012752 auxiliary agent Substances 0.000 description 2
- 238000009835 boiling Methods 0.000 description 2
- 230000003197 catalytic effect Effects 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 230000008020 evaporation Effects 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 150000002825 nitriles Chemical class 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- 239000000376 reactant Substances 0.000 description 2
- 230000002194 synthesizing effect Effects 0.000 description 2
- 229920000305 Nylon 6,10 Polymers 0.000 description 1
- 229920002302 Nylon 6,6 Polymers 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- BTGRAWJCKBQKAO-UHFFFAOYSA-N adiponitrile Chemical compound N#CCCCCC#N BTGRAWJCKBQKAO-UHFFFAOYSA-N 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 229910000316 alkaline earth metal phosphate Inorganic materials 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- 150000001408 amides Chemical class 0.000 description 1
- 150000001412 amines Chemical class 0.000 description 1
- 229960002684 aminocaproic acid Drugs 0.000 description 1
- 125000002843 carboxylic acid group Chemical group 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
- 239000007809 chemical reaction catalyst Substances 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 125000004093 cyano group Chemical group *C#N 0.000 description 1
- NNGAQKAUYDTUQR-UHFFFAOYSA-N cyclohexanimine Chemical compound N=C1CCCCC1 NNGAQKAUYDTUQR-UHFFFAOYSA-N 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- SNRUBQQJIBEYMU-UHFFFAOYSA-N dodecane Chemical group CCCCCCCCCCCC SNRUBQQJIBEYMU-UHFFFAOYSA-N 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 229920006351 engineering plastic Polymers 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910001463 metal phosphate Inorganic materials 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229910000510 noble metal Inorganic materials 0.000 description 1
- 229910052763 palladium Inorganic materials 0.000 description 1
- 239000010452 phosphate Substances 0.000 description 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 238000010992 reflux Methods 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229910052703 rhodium Inorganic materials 0.000 description 1
- 239000010948 rhodium Substances 0.000 description 1
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 229910000319 transition metal phosphate Inorganic materials 0.000 description 1
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Abstract
The utility model discloses a device for producing hexamethylene diamine by caprolactam, which mainly comprises an ammoniation dehydration reactor, a primary condenser, a secondary condenser, a tertiary condenser and a hydrogenation reactor, and is characterized in that the ammoniation dehydration reactor is provided with a feeding pipeline, and a gas phase outlet of the ammoniation dehydration reactor is connected with an inlet of the primary condenser; the gas phase outlet of the first-stage condenser is connected with the inlet of the second-stage condenser, and the first-stage condenser is provided with a liquid phase outlet; the gas phase outlet of the second-stage condenser is connected with the inlet of the third-stage condenser, and the liquid phase outlet of the second-stage condenser is connected with the inlet of the hydrogenation reactor; the third-stage condenser is provided with a gas phase outlet and a liquid phase outlet for discharging ammonia gas and waste water. The utility model discloses regard as the diluent with caprolactam water solution, reduce the accessory substance and produce, ammoniation dehydration reaction liquid is direct hydrogenation through rectification separation, reduces the energy consumption.
Description
Technical Field
The utility model belongs to the technical field of organic chemical industry, a method for producing hexamethylene diamine by caprolactam is related to, in particular to 6-aminocapronitrile and caprolactam mixture hydrogenation produce hexamethylene diamine's device.
Background
Hexamethylenediamine is a key raw material in the nylon industry, is usually used for synthesizing nylon 66 and nylon 610, and then is prepared into products such as nylon resin, nylon fibers, engineering plastics and the like. The industrial production method of the hexamethylene diamine is mainly a adiponitrile catalytic hydrogenation method, and the method produces impurity diaminocyclohexane which has large influence on the quality of nylon products while producing the hexamethylene diamine, and is difficult to separate. At present, with the increasing expansion of caprolactam production capacity and the decreasing price, the caprolactam method is expected to be popularized industrially. The caprolactam method takes caprolactam as a raw material to prepare 6-aminocapronitrile through catalytic ammoniation, and then the 6-aminocapronitrile is further subjected to catalytic hydrogenation to obtain the hexamethylene diamine.
In the prior art, patent CN107739318A discloses a method and a device for preparing 6-aminocapronitrile by a caprolactam liquid phase method, wherein the method for preparing 6-aminocapronitrile by the caprolactam liquid phase method takes caprolactam as a raw material, and caprolactam reacts with ammonia under the catalysis of phosphoric acid or phosphate to prepare 6-aminocapronitrile, the caprolactam conversion rate is only 48% -65%, and the catalyst is not easy to recover. Patent CN110423201A provides a method for synthesizing hexamethylenediamine from caprolactam as a raw material, which comprises mixing caprolactam, alkali and water, heating and refluxing to obtain 6-aminocaproate, further introducing amino protecting groups to protect terminal amino, then adding acid to neutralize and generate aminocaproic acid with amino protecting groups, drying, adding a dehydration catalyst for amide, heating and reacting in the presence of an ammonia source to convert carboxylic acid groups into cyano groups to obtain product nitrile, extracting and purifying the product nitrile, performing catalytic hydrogenation to generate corresponding amine, and removing the protecting groups to obtain hexamethylenediamine.
CN 112079725A discloses a method for producing hexamethylene diamine, ammonia, hydrogen and caprolactam are mixed and gasified to obtain mixed gas; adding a catalyst into the obtained mixed gas to perform a catalytic ammoniation reaction and a catalytic hydrogenation reaction; and then, condensing and separating the materials obtained by the reaction to obtain reaction liquid, and distilling the obtained reaction liquid to obtain the product hexamethylene diamine. The method integrates caprolactam ammoniation and hydrogenation, but has the defects of high reaction temperature and a plurality of byproducts, and has no industrial application value.
SUMMERY OF THE UTILITY MODEL
The defect that exists to prior art, the utility model provides a by the device of caprolactam production hexamethylene diamine, through preparing 6-aminocapronitrile and 6-aminocapronitrile hydrogenation production hexamethylene diamine technical organic combination to the caprolactam ammoniation, develop a method that has the production hexamethylene diamine that the energy consumption is low, the accessory substance is few, product quality is high.
The technical scheme of the utility model:
a device for producing hexamethylene diamine by caprolactam mainly comprises an ammoniation dehydration reactor, a primary condenser, a secondary condenser, a tertiary condenser and a hydrogenation reactor, and is characterized in that the ammoniation dehydration reactor is provided with a feeding pipeline, and a gas phase outlet of the ammoniation dehydration reactor is connected with an inlet of the primary condenser; the gas phase outlet of the first-stage condenser is connected with the inlet of the second-stage condenser, and the first-stage condenser is provided with a liquid phase outlet; the gas phase outlet of the second-stage condenser is connected with the inlet of the third-stage condenser, and the liquid phase outlet of the second-stage condenser is connected with the inlet of the hydrogenation reactor; the third-stage condenser is provided with a gas phase outlet and a liquid phase outlet for discharging ammonia gas and waste water.
The ammoniation dehydration reactor is a fixed bed reactor or a fluidized bed reactor.
The hydrogenation reactor is a fluidized bed reactor, a stirring reactor or a fixed bed reactor; the reactor is provided with a liquid-solid separator which is provided with an overflow port.
The hydrogenation reactor is composed of two or three similar reaction tubes, is a gas-liquid-solid three-phase boiling type fluidized bed reactor, the reaction tubes are lifted to a gas-liquid separator, unreacted hydrogen and liquid in the gas-liquid separator are separated, the hydrogen enters a hydrogen washing tower to wash out entrained solvent, then the hydrogen is pressurized and recycled by a hydrogen circulating compressor, and the washed solvent is returned to the hydrogenation reactor; the lower part of the gas-liquid separator is provided with a liquid-solid separator which is provided with a waste catalyst discharge port and an overflow port; the reaction material and the hydrogen from the hydrogen pressure boosting compressor and the hydrogen circulation compressor are supplied from the bottom of the reaction tube, respectively, and the hydrogen and the reaction liquid rise together from the reaction tube to the gas-liquid separator.
The overflow port of the liquid-solid separator is connected with a dehydration tower, the top of the dehydration tower is provided with water outlet pipeline produced water, the bottom of the dehydration tower is connected with a heavy component removal tower, the bottom of the heavy component removal tower is used for producing heavy components, and the top of the heavy component removal tower is connected with a light component removal tower; separating out light components from the top of the light component removal tower, and connecting the bottom of the light component removal tower with a hexamethylenediamine tower; separating out the hexamethylene diamine product at the top of the hexamethylene diamine tower, and arranging a caprolactam material flow outlet at the bottom of the hexamethylene diamine tower.
In one embodiment, the overflow port of the liquid-solid separator is connected with a dehydration tower, water is produced at the top of the dehydration tower, and the bottom of the dehydration tower is connected with a light component removal tower; separating out light components from the top of the light component removal tower, and connecting the bottom of the light component removal tower with a hexamethylenediamine tower; separating out the hexamethylene diamine product from the top of the hexamethylene diamine tower, arranging a caprolactam material flow outlet at the bottom, and returning the caprolactam to a caprolactam feeding evaporator before the ammoniation dehydration reactor.
The dehydration tower is provided with a flash tank in front, the inlet of the flash tank is connected with the overflow port of the liquid-solid separator, the gas outlet of the flash tank is connected with the hydrogen washing tower, and the liquid outlet of the flash tank is connected with the dehydration tower.
The front of the dehydration tower is provided with a desolventizing tower which is connected with an overflow port of a liquid-solid separator, a solvent outlet at the top of the desolventizing tower is connected with a hydrogenation reactor, and a tower bottom outlet of the desolventizing tower is connected with the dehydration tower. The front of the desolventizing tower is provided with a flash tank, the inlet of the flash tank is connected with the overflow port of the liquid-solid separator, the gas outlet of the flash tank is connected with the hydrogen washing tower, and the liquid outlet of the flash tank is connected with the feeding pipe of the desolventizing tower.
The light component removing tower is formed by connecting two towers in series, a gas phase pipeline at the top of the heavy component removing tower is connected with the bottom of the first light component removing tower, a gas phase outlet pipeline is arranged at the top of the heavy component removing tower, and the bottom of the heavy component removing tower is connected with the second light component removing tower; the top gas phase light component pipeline of the second light component removal tower is connected with the first light component removal tower, and the bottom of the second light component removal tower is connected with the hexamethylenediamine tower.
A method for producing hexamethylene diamine from caprolactam mainly comprises the following steps:
s1: carrying out ammoniation dehydration reaction on ammonia gas and caprolactam under the action of a catalyst to obtain an ammoniation dehydration reaction product;
s2: carrying out primary condensation on the product of the S1 ammoniation dehydration reaction, cooling to 300-315 ℃, and separating out heavy components; carrying out secondary condensation on the primary condensed gas phase, cooling to 140-210 ℃, and separating out condensate containing caprolactam and 6-aminocapronitrile; carrying out third-stage condensation on the gas phase of the second-stage condensation, cooling to 40-60 ℃, separating out water, and returning uncondensed ammonia gas serving as a raw material to the ammoniation dehydration reaction;
s3: carrying out hydrogenation reaction on caprolactam obtained by secondary condensation in S2 and 6-aminocapronitrile condensate under the action of a catalyst, adding water accounting for 5-200% of the total weight of the condensate during the hydrogenation reaction, and carrying out hydrogenation reaction to obtain a mixture containing hexamethylene diamine and caprolactam;
s4: separating the mixture containing the hexamethylene diamine and the caprolactam obtained in the step S3 to obtain the hexamethylene diamine and the caprolactam, and returning the caprolactam serving as a raw material to the ammoniation dehydration reaction.
The ammoniation dehydration reaction catalyst in the step S1 is one or a combination of at least two of alkaline earth metal phosphate, transition metal phosphate and IIIA metal phosphate.
The ammoniation dehydration reaction is carried out in a fixed bed reactor or a fluidized bed reactor.
In the ammonification dehydration reaction, the molar ratio of ammonia gas to caprolactam is 5-50: 1; the temperature of the ammoniation dehydration reaction is 300-500 ℃, the reaction pressure is 0-2.0 MPa, and the gas phase space velocity is 720-3600 h-1。
The hydrogenation of caprolactam and 6-aminocapronitrile in the step S3 is selective hydrogenation, only 6-aminocapronitrile is hydrogenated, and caprolactam does not participate in the hydrogenation reaction; the hydrogenation reactor is a fluidized bed reactor, a stirring reactor or a fixed bed reactor; the stirred reactor is preferably a continuous stirred reactor.
The hydrogenation catalyst of step S3 includes one or a combination of at least two of metal supported catalyst, amorphous nickel, raney nickel, and raney cobalt. The metal-supported catalyst is preferably a noble metal-supported catalyst in which the noble metal comprises at least one of platinum, palladium, nickel or rhodium and the support comprises any one of or a combination of at least two of activated carbon, silica or alumina.
The 6-aminocapronitrile hydrogenation reaction of step S3 is further added with a cocatalyst, wherein the cocatalyst is NaOH, KOH, CH3CH2ONa、CH3One or a combination of at least two of ONa.
Hydrogenation reaction in step S3: the mass ratio of the cocatalyst to the 6-aminocapronitrile is 0.001-0.2: 1; the molar ratio of the hydrogen to the 6-aminocapronitrile is 2-100: 1; the reaction temperature is 30-100 ℃, and the pressure is 0-10.0 MPaG; the mass concentration of the catalyst in the reaction section is 5-40%, and the flow rate of the liquid phase is 0.1-10.0 m/s.
Separating the mixture of hexamethylene diamine and caprolactam in the step S4: the liquid phase overflowed from the hydrogenation reactor contains hexamethylene diamine, caprolactam, water, entrained catalyst, cocatalyst and the like, flows to a filter after being flashed by a flash tank, the entrained catalyst is removed by the filter, the liquid phase mixture is sent to an auxiliary agent decanter, the cocatalyst solution is separated from the mixture, and the mixture containing hexamethylene diamine and caprolactam is sent to a dehydration tower; the temperature of the top of the dehydration tower is 45-55 ℃, the pressure is 85-95 mmHgA, water and HMI are extracted from the top of the dehydration tower, and the mixture containing hexamethylene diamine and caprolactam at the bottom of the dehydration tower is sent to a de-weighting tower; separating heavy tar containing the auxiliary agent mud from the bottom of the heavy component removal tower, and sending a mixture containing hexamethylene diamine and caprolactam separated from the top of the tower to a light component removal tower; the temperature of the top of the light component removal tower is 90-100 ℃, the pressure is 10-40 mmHgA, light components are separated from the top of the tower, and a mixture containing hexamethylene diamine and caprolactam at the bottom of the tower is sent to a hexamethylene diamine tower; the temperature of the top of the hexamethylenediamine tower is 102-106 ℃, the pressure is 30-35mmHgA, caprolactam extracted from the bottom of the tower is recycled, refined hexamethylenediamine is extracted from the side line of the higher section of the tower, and the material discharged from the top of the tower returns to the lightness-removing tower.
Another separation scheme for the hydrogenated stream: separating the mixture of hexamethylene diamine and caprolactam in the step S4: the liquid phase overflowed from the hydrogenation reactor contains hexamethylenediamine, caprolactam, water, entrained catalyst, cocatalyst and the like, flows to a filter after being flashed by a flash tank, the entrained catalyst is removed by the filter, the liquid phase mixture is sent to a cocatalyst decanter, the cocatalyst solution is separated from the mixture, and the mixture containing hexamethylenediamine and caprolactam is sent to a dehydration tower; the temperature of the top of the dehydration tower is 45-55 ℃, the pressure is 85-95 mmHgA, water and HMI are extracted from the top of the dehydration tower, and the mixture containing hexamethylene diamine and caprolactam at the bottom of the dehydration tower is sent to a light component removal tower; the temperature of the top of the light component removal tower is 90-100 ℃, the pressure is 10-40 mmHgA, light components are separated from the top of the tower, and a mixture containing hexamethylene diamine and caprolactam at the bottom of the tower is sent to a hexamethylene diamine tower; the temperature of the top of the hexamethylene diamine tower is 102-106 ℃, the pressure is 30-35mmHgA, refined hexamethylene diamine is extracted from the side line of the higher section of the tower, the material discharged from the top of the tower returns to a lightness-removing tower, the mixture containing caprolactam is extracted from the bottom of the tower and sent to a caprolactam evaporator in front of an ammoniation dehydration reactor, and heavy components are discharged from the bottom of the caprolactam evaporator.
The light component removal tower is characterized in that the light component removal tower is formed by connecting two light component removal towers in series, steam from the heavy component removal tower is supplied from the bottom of the first light component removal tower, light components separated from the top of the first light component removal tower are sent out of a battery compartment, and tower bottom liquid is sent to the second light component removal tower through a second light component removal tower feeding tank; in the second lightness-removing tower, the light components remained in the feed are separated out at the top of the tower, the light components separated out at the top of the tower are returned to the first lightness-removing tower for further treatment, and the hexamethylenediamine and caprolactam liquid containing a small amount of heavy components at the bottom of the tower are sent to the hexamethylenediamine tower.
Characteristics and effects of the utility model
The utility model discloses carry out 6-aminocapronitrile hydrogenation with caprolactam mixture stream, the caprolactam aqueous solution is favorable to 6-aminocapronitrile hydrogenation to can control the caprolactam not by the hydrogenation, utilize the caprolactam aqueous solution as 6-aminocapronitrile hydrogenation reaction diluent, need not add ethanol as the diluent, reduced accessory substance N-Et-HMD (N-ethyl hexamethylene diamine), BHT (dihexyl triamine), tar production.
The utility model discloses pass through the condensation mode separation with caprolactam ammoniation dehydration reactant, retrieve the ammonia, do not pass through rectification separation, directly carry out the hydrogenation with 6-aminocapronitrile and caprolactam mixture together, through adding water, realize only 6-aminocapronitrile hydrogenation, caprolactam is not hydrogenated.
The utility model discloses saved the energy consumption of ammoniation dehydration reactant rectification separation, also reduced hydrogenation's accessory substance simultaneously, the hexamethylene diamine product of can reducing steam consumption 1.5 t/t. The one-way conversion rate of caprolactam can reach 50-70%, and the selectivity of hexamethylene diamine can reach 99%.
The utility model discloses an preferred embodiment does not establish and takes off heavy tower when hydrogenation product separation, will contain the caprolactam of heavy branch and pass through ammoniation dehydration reaction feeding caprolactam evaporimeter, through caprolactam evaporation, subtracts the chemical separation flow like this, can reduce steam consumption 0.5t/t product simultaneously.
Drawings
FIG. 1 is a schematic diagram showing the structure of a device for preparing hexamethylenediamine from caprolactam;
wherein: 1-an ammoniation dehydration reactor, 2-a first-stage condenser, 3-a second-stage condenser, 4-a third-stage condenser and 5-a hydrogenation reactor;
a-ammoniation dehydration reaction feed stream, B-heavy components condensed by a first-stage condenser, C-third-stage condenser condensate liquid water and D-third-stage condenser gas-phase ammonia gas.
Detailed Description
The present invention will be further described with reference to the following examples and drawings, but the present invention is not limited to these examples.
As can be seen from figure 1, the utility model relates to a device for producing hexamethylene diamine by caprolactam, which mainly comprises an ammonification dehydration reactor, a first-level condenser, a second-level condenser, a third-level condenser and a hydrogenation reactor, and is characterized in that the ammonification dehydration reactor is provided with a feeding pipeline, and a gas phase outlet of the ammonification dehydration reactor is connected with an inlet of the first-level condenser; the gas phase outlet of the first-stage condenser is connected with the inlet of the second-stage condenser, and the first-stage condenser is provided with a liquid phase outlet; the gas phase outlet of the second-stage condenser is connected with the inlet of the third-stage condenser, and the liquid phase outlet of the second-stage condenser is connected with the inlet of the hydrogenation reactor; the third-stage condenser is provided with a gas phase outlet and a liquid phase outlet for discharging ammonia gas and waste water.
The ammoniation dehydration reactor is a fixed bed reactor or a fluidized bed reactor.
The hydrogenation reactor is a fluidized bed reactor, a stirring reactor or a fixed bed reactor; the reactor is provided with a liquid-solid separator which is provided with an overflow port.
The hydrogenation reactor is composed of two or three similar reaction tubes, is a gas-liquid-solid three-phase boiling type fluidized bed reactor, the reaction tubes are lifted to a gas-liquid separator, unreacted hydrogen and liquid in the gas-liquid separator are separated, the hydrogen enters a hydrogen washing tower to wash out entrained solvent, then the hydrogen is pressurized and recycled by a hydrogen circulating compressor, and the washed solvent is returned to the hydrogenation reactor; the lower part of the gas-liquid separator is provided with a liquid-solid separator which is provided with a waste catalyst discharge port and an overflow port; the reaction material and the hydrogen from the hydrogen pressure boosting compressor and the hydrogen circulation compressor are supplied from the bottom of the reaction tube, respectively, and the hydrogen and the reaction liquid rise together from the reaction tube to the gas-liquid separator.
The overflow port of the liquid-solid separator is connected with a dehydration tower, the top of the dehydration tower is provided with water outlet pipeline produced water, the bottom of the dehydration tower is connected with a heavy component removal tower, the bottom of the heavy component removal tower is used for producing heavy components, and the top of the heavy component removal tower is connected with a light component removal tower; separating out light components from the top of the light component removal tower, and connecting the bottom of the light component removal tower with a hexamethylenediamine tower; separating out the hexamethylene diamine product at the top of the hexamethylene diamine tower, and arranging a caprolactam material flow outlet at the bottom of the hexamethylene diamine tower.
In one embodiment, the overflow port of the liquid-solid separator is connected with a dehydration tower, water is produced at the top of the dehydration tower, and the bottom of the dehydration tower is connected with a light component removal tower; separating out light components from the top of the light component removal tower, and connecting the bottom of the light component removal tower with a hexamethylenediamine tower; separating out the hexamethylene diamine product from the top of the hexamethylene diamine tower, arranging a caprolactam material flow outlet at the bottom, and returning the caprolactam to a caprolactam feeding evaporator before the ammoniation dehydration reactor.
The dehydration tower is provided with a flash tank in front, the inlet of the flash tank is connected with the overflow port of the liquid-solid separator, the gas outlet of the flash tank is connected with the hydrogen washing tower, and the liquid outlet of the flash tank is connected with the dehydration tower.
The front of the dehydration tower is provided with a desolventizing tower which is connected with an overflow port of a liquid-solid separator, a solvent outlet at the top of the desolventizing tower is connected with a hydrogenation reactor, and a tower bottom outlet of the desolventizing tower is connected with the dehydration tower. The front of the desolventizing tower is provided with a flash tank, the inlet of the flash tank is connected with the overflow port of the liquid-solid separator, the gas outlet of the flash tank is connected with the hydrogen washing tower, and the liquid outlet of the flash tank is connected with the feeding pipe of the desolventizing tower.
The light component removing tower is formed by connecting two towers in series, a gas phase pipeline at the top of the heavy component removing tower is connected with the bottom of the first light component removing tower, a gas phase outlet pipeline is arranged at the top of the heavy component removing tower, and the bottom of the heavy component removing tower is connected with the second light component removing tower; the top gas phase light component pipeline of the second light component removal tower is connected with the first light component removal tower, and the bottom of the second light component removal tower is connected with the hexamethylenediamine tower.
The following are several embodiments of the present invention.
Example 1:
production of hexamethylenediamine from caprolactam
Evaporating caprolactam in an evaporator, and mixing the caprolactam with hot ammonia gas according to a mol ratio of 1: 30, mixing the mixture, putting the mixture into a fixed bed reactor filled with a magnesium phosphate catalyst, controlling the temperature to be 300-400 ℃, and controlling the reaction pressure to be 0-1.0 MPa; the gas phase space velocity is 720-3600 h-1；
Carrying out primary condensation on the ammoniation dehydration reaction product obtained above, cooling to 300-315 ℃, and separating out heavy components; carrying out secondary condensation on the primary condensed gas phase, cooling to 140-210 ℃, and separating out condensate containing caprolactam and 6-aminocapronitrile; carrying out third-stage condensation on the gas phase of the second-stage condensation, cooling to 40-60 ℃, separating out water, and returning gas-phase ammonia gas to the ammoniation dehydration reaction to be used as a raw material for recycling;
and (3) carrying out hydrogenation reaction on caprolactam obtained by secondary condensation and 6-aminocapronitrile condensate under the action of a catalyst to obtain a mixture containing crude hexamethylene diamine and caprolactam. The hydrogenation reaction is carried out in a fluidized bed reactor consisting of three reaction tubes, the hydrogenation catalyst is of a Raney nickel type, the cocatalyst is NaOH, and water are added into reaction feed liquid: the mass ratio of (caprolactam + 6-aminocapronitrile) is 0.5:1, the mass ratio of the cocatalyst to 6-aminocapronitrile is 0.001-0.1: 1, and the molar ratio of hydrogen to 6-aminocapronitrile is 2-8: 1; the reaction pressure is gauge pressure of 1.5-3.0 MPa at 60-80 ℃, the mass concentration of the catalyst at the reaction section is 25%, and the flow rate of the reaction liquid phase is 2.0-4.0 m/s;
the method comprises the following steps of (1) enabling a liquid phase overflowing from a hydrogenation reactor to contain hexamethylenediamine, caprolactam, water, an entrained catalyst, NaOH and the like to flow to a filter feeding tank after being flashed by a flash tank, removing the entrained catalyst through a filter, feeding a hexamethylenediamine and caprolactam mixture of the liquid phase solution into an NaOH decanter, separating the NaOH solution from the hexamethylenediamine and caprolactam solution, feeding a crude hexamethylenediamine and caprolactam solution into a dehydration tower, separating water and HMI (cyclohexylimine) from the hexamethylenediamine and caprolactam mixture under the conditions that the temperature of the tower top is 45-55 ℃ and the pressure of the tower top is 85-95 mmHgA, pumping out the mixture from the tower top, feeding the mixture into a wastewater pretreatment system, feeding a hexamethylenediamine and caprolactam mixture flow liquid at the tower bottom into a de-weighting tower for treatment, and separating heavy tar containing NaOH slurry from the hexamethylenediamine and caprolactam liquid at the tower bottom of the de-weighting tower; sending the crude hexamethylenediamine and caprolactam liquid at the top of the tower to a lightness removing tower for treatment, separating light components such as DCH (diaminocyclohexane) from the top of the tower under the conditions that the temperature at the top of the tower is 90-100 ℃ and the pressure at the top of the tower is 10-40 mmHgA, and sending the solution containing hexamethylenediamine and caprolactam at the bottom of the tower to a hexamethylenediamine tower; under the conditions that the temperature of the top of the hexamethylenediamine tower is 102-106 ℃ and the pressure of the top of the hexamethylenediamine tower is 30-35mmHgA, extracting caprolactam from the bottom of the hexamethylenediamine tower for cyclic utilization; and (3) collecting refined hexamethylene diamine at the side line of the higher section of the tower, sending the refined hexamethylene diamine to a hexamethylene diamine storage tank in a tank field, and returning the discharged material at the top of the hexamethylene diamine tower to a light component removal tower feeding tank for retreatment.
The conversion per pass of the ammonification and dehydration of the caprolactam is 50-70 percent, the purity of the hexamethylene diamine product is 99.9 percent, the generation of a by-product N-Et-HMD (N-ethylhexamethylene diamine) is reduced because ethanol is not used as a solvent, the N-Et-HMD cannot be detected, meanwhile, a caprolactam water solution plays a role of a diluent in the hydrogenation reaction process, the hydrogenation selectivity of the 6-aminocapronitrile is improved, the selectivity reaches 99 percent, and the consumption of the raw material caprolactam is reduced. Conventionally, ethanol is used as a diluent, and the amount of N-Et-HMD in a hydrogenation product reaches 1.5-2.5%.
Because the rectification separation of the caprolactam ammoniation dehydration reaction material flow is not needed, the steam consumption can be reduced by 1.5 t/t.
Example 2
Production of hexamethylenediamine from caprolactam
Evaporating caprolactam in an evaporator, and mixing the caprolactam with hot ammonia gas according to a mol ratio of 1: 30, mixing and feeding the mixture into a fixed bed reactor filled with a magnesium phosphate catalyst, controlling the temperature at 300 ℃ and the temperature at 400 ℃, and controlling the reaction pressure at 0-1.0 MPa; the gas phase space velocity is 730-3600 h-1；
Performing primary condensation on the ammoniation dehydration reaction product obtained above, cooling to the temperature of 300 ℃ and 315 ℃, and separating out heavy components; then the primary condensed gas phase is subjected to secondary condensation, cooled to 140 ℃ and 210 ℃, and condensed liquid containing caprolactam and 6-aminocapronitrile is separated; carrying out third-stage condensation on the gas phase of the second-stage condensation, cooling to 40-60 ℃, separating water, and returning gas-phase ammonia gas to the ammoniation dehydration reaction to be used as a raw material for recycling;
and (3) carrying out hydrogenation reaction on caprolactam obtained by secondary condensation and 6-aminocapronitrile condensate under the action of a catalyst to obtain a mixture containing crude hexamethylene diamine and caprolactam. The hydrogenation reaction is carried out in a continuous stirring reactor, the hydrogenation catalyst is of a Raney nickel type, the concentration and mass concentration of the catalyst are 5% -30%, the cocatalyst is NaOH, and water are added into the reaction solution: the mass ratio of (caprolactam + 6-aminocapronitrile) is 0.8:1, the mass ratio of the cocatalyst to 6-aminocapronitrile is 0.001-0.1: 1, and the molar ratio of hydrogen to 6-aminocapronitrile is 2-8: 1; the reaction pressure is 1.5-3.0 MPa gauge pressure at 60-80 ℃;
the method comprises the following steps of (1) enabling a liquid phase overflowing from a hydrogenation reactor to contain hexamethylenediamine, caprolactam, water, an entrained catalyst, NaOH and the like to flow to a filter feeding tank after being flashed by a flash tank, removing the entrained catalyst through a filter, feeding a hexamethylenediamine and caprolactam mixture of the liquid phase solution into an NaOH decanter, separating the NaOH solution from crude hexamethylenediamine and caprolactam solution, feeding the crude hexamethylenediamine and caprolactam solution into a dehydration tower, separating water and HMI (human machine interface) from the crude hexamethylenediamine and caprolactam mixture under the conditions that the temperature of the tower top is 45-55 ℃ and the pressure of the tower top is 85-95 mmHgA, pumping out the mixture from the tower top, feeding the mixture into a wastewater pretreatment system, feeding a hexamethylenediamine and caprolactam mixture flow liquid at the tower bottom into a de-weighting tower for treatment, and separating heavy tar containing NaOH mud from the hexamethylenediamine and caprolactam liquid at the tower bottom of the de-weighting tower; sending the crude hexamethylenediamine and caprolactam liquid at the top of the tower to a lightness-removing tower for treatment, separating light components such as DCH from the top of the tower under the conditions that the temperature at the top of the tower is 90-100 ℃ and the pressure at the top of the tower is 10-40 mmHgA, and sending the solution containing hexamethylenediamine and caprolactam at the bottom of the tower to a hexamethylenediamine tower; under the conditions that the temperature of the top of the hexamethylenediamine tower is 102-106 ℃ and the pressure of the top of the hexamethylenediamine tower is 30-35mmHgA, extracting caprolactam from the bottom of the hexamethylenediamine tower for cyclic utilization; and (3) collecting refined hexamethylene diamine at the side line of the higher section of the tower, sending the refined hexamethylene diamine to a hexamethylene diamine storage tank in a tank field, and returning the discharged material at the top of the hexamethylene diamine tower to a light component removal tower feeding tank for retreatment.
The conversion per pass of the ammonification and dehydration of the caprolactam is 50-70 percent, the purity of the hexamethylene diamine product is 99.9 percent, the generation of a by-product N-Et-HMD (N-ethylhexamethylene diamine) is reduced because ethanol is not used as a solvent, the N-Et-HMD cannot be detected, meanwhile, a caprolactam water solution plays a role of a diluent in the hydrogenation reaction process, the hydrogenation selectivity of the 6-aminocapronitrile is improved, the selectivity reaches 99 percent, and the consumption of the raw material caprolactam is reduced.
The steam consumption can be reduced by 1.5t/t because the rectification separation of caprolactam ammonification dehydration reaction material flow is not needed.
Example 3
Production of hexamethylenediamine from caprolactam
Evaporating caprolactam in an evaporator, and mixing the caprolactam with hot ammonia gas according to a mol ratio of 1: 30, mixing the mixture, putting the mixture into a fixed bed reactor filled with a magnesium phosphate catalyst, controlling the temperature to be 300-400 ℃, and controlling the reaction pressure to be 0-1.0 MPa; the gas phase space velocity is 730-3600 h-1；
Performing primary condensation on the ammoniation dehydration reaction product obtained above, cooling to the temperature of 300 ℃ and 315 ℃, and separating out heavy components; then the primary condensed gas phase is subjected to secondary condensation, cooled to 140 ℃ and 180 ℃, and condensed liquid containing caprolactam and 6-aminocapronitrile is separated; carrying out third-stage condensation on the gas phase of the second-stage condensation, cooling to 40-60 ℃, separating water, and returning gas-phase ammonia gas to the ammoniation dehydration reaction to be used as a raw material for recycling;
and (3) carrying out hydrogenation reaction on caprolactam obtained by secondary condensation and 6-aminocapronitrile condensate under the action of a catalyst to obtain a mixture containing crude hexamethylene diamine and caprolactam. The hydrogenation reaction is carried out in a fixed bed reactor, the hydrogenation catalyst is a Raney nickel type forming catalyst, the catalyst is filled in the fixed bed reactor, the cocatalyst is NaOH, and water are added into reaction feed liquid: the mass ratio of (caprolactam + 6-aminocapronitrile) is 0.5:1, the mass ratio of the cocatalyst to 6-aminocapronitrile is 0.001-0.1: 1, and the molar ratio of hydrogen to 6-aminocapronitrile is 2-8: 1; 60-80 ℃, the reaction pressure is the gauge pressure of 0.5-3.0 MPa, and the airspeed of the reaction liquid phase is 0.5-50h-1；
The method comprises the following steps of (1) enabling a liquid phase overflowing from a hydrogenation reactor to contain hexamethylenediamine, caprolactam, water, an entrained catalyst, NaOH and the like to flow to a filter feeding tank after being flashed by a flash tank, removing the entrained catalyst through a filter, feeding a hexamethylenediamine and caprolactam mixture of the liquid phase solution into an NaOH decanter, separating the NaOH solution from crude hexamethylenediamine and caprolactam solution, feeding the crude hexamethylenediamine and caprolactam solution into a dehydration tower, separating water and HMI (human machine interface) from the crude hexamethylenediamine and caprolactam mixture under the conditions that the temperature of the tower top is 45-55 ℃ and the pressure of the tower top is 85-95 mmHgA, pumping out the mixture from the tower top, feeding the mixture into a wastewater pretreatment system, feeding a hexamethylenediamine and caprolactam mixture flow liquid at the tower bottom into a de-weighting tower for treatment, and separating heavy tar containing NaOH mud from the hexamethylenediamine and caprolactam liquid at the tower bottom of the de-weighting tower; sending the crude hexamethylenediamine and caprolactam liquid at the top of the tower to a lightness-removing tower for treatment, separating light components such as DCH from the top of the tower under the conditions that the temperature at the top of the tower is 90-100 ℃ and the pressure at the top of the tower is 10-40 mmHgA, and sending the solution containing hexamethylenediamine and caprolactam at the bottom of the tower to a hexamethylenediamine tower; under the conditions that the temperature of the top of the hexamethylenediamine tower is 102-106 ℃ and the pressure of the top of the hexamethylenediamine tower is 30-35mmHgA, extracting caprolactam from the bottom of the hexamethylenediamine tower for cyclic utilization; and (3) collecting refined hexamethylene diamine at the side line of the higher section of the tower, sending the refined hexamethylene diamine to a hexamethylene diamine storage tank in a tank field, and returning the discharged material at the top of the hexamethylene diamine tower to a light component removal tower feeding tank for retreatment.
The conversion per pass of the ammonification and dehydration of the caprolactam is 40-50 percent, the purity of the hexamethylene diamine product is 99.9 percent, the generation of a by-product N-Et-HMD (N-ethylhexamethylene diamine) is reduced because ethanol is not used as a solvent, the N-Et-HMD cannot be detected, meanwhile, a caprolactam water solution plays a role of a diluent in the hydrogenation reaction process, the hydrogenation selectivity of the 6-aminocapronitrile is improved, the selectivity reaches 99 percent, and the consumption of the raw material caprolactam is reduced.
The steam consumption can be reduced by 1.5t/t because the rectification separation of caprolactam ammonification dehydration reaction material flow is not needed.
Example 4
Production of hexamethylenediamine from caprolactam
Evaporating caprolactam in an evaporator, and mixing the caprolactam with hot ammonia gas according to a mol ratio of 1: 30, mixing the mixture, putting the mixture into a fixed bed reactor filled with a magnesium phosphate catalyst, controlling the temperature to be 300-400 ℃, and controlling the reaction pressure to be 0-1.0 MPa; the gas phase space velocity is 730-3600 h-1；
Carrying out primary condensation on the ammoniation dehydration reaction product obtained above, cooling to 300-315 ℃, and separating out heavy components; carrying out secondary condensation on the primary condensed gas phase, cooling to 140-210 ℃, and separating out condensate containing caprolactam and 6-aminocapronitrile; carrying out third-stage condensation on the gas phase of the second-stage condensation, cooling to 40-60 ℃, separating out water, and returning gas-phase ammonia gas to the ammoniation dehydration reaction to be used as a raw material for recycling;
and (3) carrying out hydrogenation reaction on caprolactam obtained by secondary condensation and 6-aminocapronitrile condensate under the action of a catalyst to obtain a mixture containing crude hexamethylene diamine and caprolactam. The hydrogenation reaction is carried out in a fixed bed reactor, the hydrogenation catalyst is a Raney nickel type forming catalyst, the catalyst is filled in the fixed bed reactor, the cocatalyst is NaOH, and water are added into reaction feed liquid: the mass ratio of (caprolactam + 6-aminocapronitrile) is 1.5:1, the mass ratio of the cocatalyst to 6-aminocapronitrile is 0.001-0.1: 1, and the molar ratio of hydrogen to 6-aminocapronitrile is 2-8: 1; 60-80 ℃, the reaction pressure is the gauge pressure of 0.5-3.0 MPa, and the airspeed of the reaction liquid phase is 0.5-50h-1；
Separating a mixture containing crude hexamethylene diamine and caprolactam, feeding a liquid phase overflowing from a hydrogenation reactor containing hexamethylene diamine, caprolactam, water, an entrained catalyst, NaOH and the like after flash evaporation by a flash tank to a filter feeding tank, removing the entrained catalyst by a filter, feeding the hexamethylene diamine and caprolactam mixture of the liquid phase solution to an NaOH decanter, separating the NaOH solution from the crude hexamethylene diamine and caprolactam solution, feeding the crude hexamethylene diamine and caprolactam solution to a dehydration tower, separating water and HMI (human machine interface) from the crude hexamethylene diamine and caprolactam mixture after the water and the HMI are separated from the crude hexamethylene diamine and caprolactam mixture at the tower top temperature of 45-55 ℃ and the tower top pressure of 85-95 mmHgA, pumping the water and HMI and the caprolactam mixture from the tower top to a wastewater pretreatment system, feeding the hexamethylene diamine and caprolactam mixture flow liquid at the tower bottom to a lightness removing tower for treatment, and separating light components such as DCH from the tower top under the conditions of the tower top temperature of 90-100 ℃ and the tower top pressure of 10-40 mmHgA, the solution containing hexanediamine and caprolactam at the bottom of the tower is sent to a hexanediamine tower; extracting caprolactam from the bottom of a hexamethylenediamine tower under the conditions that the temperature of the top of the hexamethylenediamine tower is 102-106 ℃ and the pressure of the top of the hexamethylenediamine tower is 30-35mmHgA, sending the caprolactam to a caprolactam evaporator fed by an ammoniation dehydration reaction, and discharging heavy components from the bottom of the caprolactam evaporator; and (3) collecting refined hexamethylene diamine at the side line of the higher section of the tower, sending the refined hexamethylene diamine to a hexamethylene diamine storage tank in a tank field, and returning the discharged material at the top of the hexamethylene diamine tower to a light component removal tower feeding tank for retreatment.
The conversion per pass of the ammonification and dehydration of the caprolactam is 40-50 percent, the purity of the hexamethylene diamine product is 99.9 percent, the generation of a by-product N-Et-HMD (N-ethylhexamethylene diamine) is reduced because ethanol is not used as a solvent, the N-Et-HMD cannot be detected, meanwhile, a caprolactam water solution plays a role of a diluent in the hydrogenation reaction process, the hydrogenation selectivity of the 6-aminocapronitrile is improved, the selectivity reaches 99 percent, and the consumption of the raw material caprolactam is reduced.
In the embodiment, caprolactam fed by ammoniation dehydration reaction is used for evaporating to remove heavy components, a heavy component removing tower in the separation of hydrogenation products is omitted, and the steam consumption of each ton of products can be reduced by 0.5t/t of hexamethylene diamine. Thus, the steam consumption can be reduced by 2.0t/t compared with the prior separation process.
Claims (10)
1. A device for producing hexamethylene diamine by caprolactam mainly comprises an ammoniation dehydration reactor, a primary condenser, a secondary condenser, a tertiary condenser and a hydrogenation reactor, and is characterized in that the ammoniation dehydration reactor is provided with a feeding pipeline, and a gas phase outlet of the ammoniation dehydration reactor is connected with an inlet of the primary condenser; the gas phase outlet of the first-stage condenser is connected with the inlet of the second-stage condenser, and the first-stage condenser is provided with a liquid phase outlet; the gas phase outlet of the second-stage condenser is connected with the inlet of the third-stage condenser, and the liquid phase outlet of the second-stage condenser is connected with the inlet of the hydrogenation reactor; the third-stage condenser is provided with a gas phase outlet and a liquid phase outlet for discharging ammonia gas and waste water.
2. The apparatus for producing hexamethylenediamine from caprolactam according to claim 1, wherein the ammoniation dehydration reactor is a fixed bed reactor or a fluidized bed reactor.
3. The apparatus for producing hexamethylenediamine from caprolactam according to claim 1, wherein the hydrogenation reactor is a fluidized bed reactor, a stirred reactor or a fixed bed reactor; the reactor is provided with a liquid-solid separator which is provided with an overflow port.
4. The apparatus for producing hexanediamine from caprolactam according to claim 1, wherein said hydrogenation reactor is composed of two or three similar reaction tubes, and is a gas, liquid and solid three-phase fluidized bed reactor, and the reaction tubes are raised to a gas-liquid separator; the lower part of the gas-liquid separator is provided with a liquid-solid separator which is provided with a waste catalyst discharge port and an overflow port; the reaction material and the hydrogen from the hydrogen pressure boosting compressor and the hydrogen circulation compressor are supplied from the bottom of the reaction tube, respectively, and the hydrogen and the reaction liquid rise together from the reaction tube to the gas-liquid separator.
5. The apparatus for producing hexanediamine from caprolactam of claim 3, wherein the overflow port of the liquid-solid separator is connected with a dehydration column, the top of the dehydration column is provided with a water outlet pipeline, the bottom of the dehydration column is connected with a heavy component removal column, the bottom of the heavy component removal column is used for extracting heavy components, and the top of the heavy component removal column is connected with a light component removal column; the bottom of the light component removal tower is connected with a hexamethylenediamine tower; separating out the hexamethylene diamine product at the top of the hexamethylene diamine tower, and arranging a caprolactam material flow outlet at the bottom of the hexamethylene diamine tower.
6. The apparatus for producing hexanediamine from caprolactam of claim 3, wherein the overflow port of the liquid-solid separator is connected with a dehydration column, the water is produced at the top of the dehydration column, and the bottom of the dehydration column is connected with a light component removal column; separating out light components from the top of the light component removal tower, and connecting the bottom of the light component removal tower with a hexamethylenediamine tower; separating out the hexamethylene diamine product from the top of the hexamethylene diamine tower, arranging a caprolactam material flow outlet at the bottom, and returning the caprolactam to a caprolactam feeding evaporator before the ammoniation dehydration reactor.
7. The apparatus according to claim 5 or 6, wherein a flash tank is arranged in front of the dehydration tower, an inlet of the flash tank is connected with an overflow port of the liquid-solid separator, a gas phase outlet of the flash tank is connected with the hydrogen washing tower, and a liquid phase outlet of the flash tank is connected with the dehydration tower.
8. The apparatus according to claim 5 or 6, wherein a desolventizing tower is arranged in front of the dehydrating tower, the desolventizing tower is connected with an overflow port of a liquid-solid separator, a solvent outlet at the top of the desolventizing tower is connected with the hydrogenation reactor, and a solvent outlet at the bottom of the desolventizing tower is connected with the dehydrating tower.
9. The apparatus of claim 8, wherein a flash tank is arranged in front of the desolventizing tower, an inlet of the flash tank is connected with an overflow port of the liquid-solid separator, a gas phase outlet of the flash tank is connected with the hydrogen washing tower, and a liquid phase outlet of the flash tank is connected with a feeding pipe of the desolventizing tower.
10. The apparatus for producing hexanediamine from caprolactam of claim 5, wherein the lightness-removing column comprises two columns connected in series, the top gas phase line of the heavies-removing column is connected with the bottom of the first lightness-removing column, the top of the first lightness-removing column is provided with a gas phase outlet line, and the bottom of the first lightness-removing column is connected with the second lightness-removing column; the top gas phase light component pipeline of the second light component removal tower is connected with the first light component removal tower, and the bottom of the second light component removal tower is connected with the hexamethylenediamine tower.
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Effective date of registration: 20211110 Address after: 315812 room b602, building 1, No. 275 Xintuo Road, Daxie Development Zone, Ningbo, Zhejiang Patentee after: Ningbo Jiaer New Material Technology Co., Ltd Address before: 414000 xiangtian International Garden, qiusuo West Road, Yueyanglou District, Yueyang City, Hunan Province Patentee before: Chen natural |