CN114507170B - Process for preparing caprolactam - Google Patents
Process for preparing caprolactam Download PDFInfo
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- CN114507170B CN114507170B CN202210176946.8A CN202210176946A CN114507170B CN 114507170 B CN114507170 B CN 114507170B CN 202210176946 A CN202210176946 A CN 202210176946A CN 114507170 B CN114507170 B CN 114507170B
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- cyclohexanone oxime
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- bed layer
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- JBKVHLHDHHXQEQ-UHFFFAOYSA-N epsilon-caprolactam Chemical compound O=C1CCCCCN1 JBKVHLHDHHXQEQ-UHFFFAOYSA-N 0.000 title claims abstract description 112
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 18
- VEZUQRBDRNJBJY-UHFFFAOYSA-N cyclohexanone oxime Chemical compound ON=C1CCCCC1 VEZUQRBDRNJBJY-UHFFFAOYSA-N 0.000 claims abstract description 229
- 239000003054 catalyst Substances 0.000 claims abstract description 56
- 238000000034 method Methods 0.000 claims abstract description 37
- 238000006237 Beckmann rearrangement reaction Methods 0.000 claims abstract description 29
- 239000012159 carrier gas Substances 0.000 claims abstract description 27
- 230000008569 process Effects 0.000 claims abstract description 18
- 238000006555 catalytic reaction Methods 0.000 claims abstract description 4
- 238000002309 gasification Methods 0.000 claims description 97
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 29
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 24
- 229910052710 silicon Inorganic materials 0.000 claims description 20
- 239000010703 silicon Substances 0.000 claims description 20
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical group [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 19
- 239000002808 molecular sieve Substances 0.000 claims description 14
- URGAHOPLAPQHLN-UHFFFAOYSA-N sodium aluminosilicate Chemical compound [Na+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O URGAHOPLAPQHLN-UHFFFAOYSA-N 0.000 claims description 14
- 229910052757 nitrogen Inorganic materials 0.000 claims description 12
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 8
- 239000010408 film Substances 0.000 claims description 8
- 239000011552 falling film Substances 0.000 claims description 7
- 239000010936 titanium Substances 0.000 claims description 7
- 229910052719 titanium Inorganic materials 0.000 claims description 7
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 6
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims description 6
- 239000002904 solvent Substances 0.000 claims description 6
- 239000000126 substance Substances 0.000 claims description 5
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 claims description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 4
- 229910052796 boron Inorganic materials 0.000 claims description 4
- 230000000630 rising effect Effects 0.000 claims description 4
- 229910052782 aluminium Inorganic materials 0.000 claims description 3
- 229910052786 argon Inorganic materials 0.000 claims description 3
- 239000001569 carbon dioxide Substances 0.000 claims description 3
- 229910002092 carbon dioxide Inorganic materials 0.000 claims description 3
- 238000010438 heat treatment Methods 0.000 claims description 3
- 230000007423 decrease Effects 0.000 claims description 2
- DNIAPMSPPWPWGF-GSVOUGTGSA-N (R)-(-)-Propylene glycol Chemical compound C[C@@H](O)CO DNIAPMSPPWPWGF-GSVOUGTGSA-N 0.000 claims 1
- 238000004939 coking Methods 0.000 abstract description 8
- 238000003763 carbonization Methods 0.000 abstract description 6
- 230000002035 prolonged effect Effects 0.000 abstract description 4
- 238000009833 condensation Methods 0.000 abstract description 3
- 230000005494 condensation Effects 0.000 abstract description 3
- 230000009471 action Effects 0.000 abstract description 2
- 239000007795 chemical reaction product Substances 0.000 description 39
- 239000000047 product Substances 0.000 description 28
- 238000006243 chemical reaction Methods 0.000 description 20
- 239000012071 phase Substances 0.000 description 15
- YPRQFESOPJGYLW-UHFFFAOYSA-N n-cyclohexylidenehydroxylamine;methanol Chemical compound OC.ON=C1CCCCC1 YPRQFESOPJGYLW-UHFFFAOYSA-N 0.000 description 14
- 239000007789 gas Substances 0.000 description 10
- 230000000694 effects Effects 0.000 description 8
- 239000012808 vapor phase Substances 0.000 description 8
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 7
- 230000000052 comparative effect Effects 0.000 description 6
- 230000003197 catalytic effect Effects 0.000 description 5
- 230000008016 vaporization Effects 0.000 description 5
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 4
- 150000001875 compounds Chemical class 0.000 description 4
- 230000009849 deactivation Effects 0.000 description 4
- 150000002191 fatty alcohols Chemical class 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 238000009834 vaporization Methods 0.000 description 4
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 3
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 3
- 229910052742 iron Inorganic materials 0.000 description 3
- 238000002360 preparation method Methods 0.000 description 3
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 2
- LRHPLDYGYMQRHN-UHFFFAOYSA-N N-Butanol Chemical compound CCCCO LRHPLDYGYMQRHN-UHFFFAOYSA-N 0.000 description 2
- DKGAVHZHDRPRBM-UHFFFAOYSA-N Tert-Butanol Chemical compound CC(C)(C)O DKGAVHZHDRPRBM-UHFFFAOYSA-N 0.000 description 2
- BFNBIHQBYMNNAN-UHFFFAOYSA-N ammonium sulfate Chemical compound N.N.OS(O)(=O)=O BFNBIHQBYMNNAN-UHFFFAOYSA-N 0.000 description 2
- 229910052921 ammonium sulfate Inorganic materials 0.000 description 2
- 235000011130 ammonium sulphate Nutrition 0.000 description 2
- 239000006227 byproduct Substances 0.000 description 2
- 239000012295 chemical reaction liquid Substances 0.000 description 2
- 239000000571 coke Substances 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- ZXEKIIBDNHEJCQ-UHFFFAOYSA-N isobutanol Chemical compound CC(C)CO ZXEKIIBDNHEJCQ-UHFFFAOYSA-N 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 239000007791 liquid phase Substances 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 229920001778 nylon Polymers 0.000 description 2
- BDERNNFJNOPAEC-UHFFFAOYSA-N propan-1-ol Chemical compound CCCO BDERNNFJNOPAEC-UHFFFAOYSA-N 0.000 description 2
- 238000007086 side reaction Methods 0.000 description 2
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 1
- 238000006675 Beckmann reaction Methods 0.000 description 1
- 239000004677 Nylon Substances 0.000 description 1
- 235000011114 ammonium hydroxide Nutrition 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- -1 cyclohexanone oxime propanol Chemical compound 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 238000004817 gas chromatography Methods 0.000 description 1
- 238000010574 gas phase reaction Methods 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 230000002779 inactivation Effects 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- TUNNMABEARBOPB-UHFFFAOYSA-N n-cyclohexylidenehydroxylamine;ethanol Chemical compound CCO.ON=C1CCCCC1 TUNNMABEARBOPB-UHFFFAOYSA-N 0.000 description 1
- 238000010606 normalization Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000008707 rearrangement Effects 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D201/00—Preparation, separation, purification or stabilisation of unsubstituted lactams
- C07D201/02—Preparation of lactams
- C07D201/04—Preparation of lactams from or via oximes by Beckmann rearrangement
-
- 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
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Other In-Based Heterocyclic Compounds (AREA)
Abstract
The present invention provides a process for preparing caprolactam. The method comprises the following steps: the method comprises the steps of conveying a gasified product containing cyclohexanone oxime and carrier gas into a reactor, wherein a catalyst is filled in the reactor, the cyclohexanone oxime undergoes a gas-phase Beckmann rearrangement reaction to generate caprolactam under the catalysis of the catalyst, the reactor comprises n fixed bed layers which are sequentially communicated, the catalyst is filled in each fixed bed layer, n is more than or equal to 2 and less than or equal to 6, and n is a natural number. By adopting the technical scheme, the cyclohexanone oxime is conveyed into the reactor with the plurality of communicated fixed bed layers to carry out the gas-phase Beckmann rearrangement reaction under the action of the carrier gas, so that the problems of condensation and carbonization of the cyclohexanone oxime in the feeding process can be effectively controlled, the coking of the catalyst can be effectively reduced, the service time of the catalyst is prolonged, the shutdown risk of the device caused by the replacement of the catalyst is further reduced, and the production efficiency of caprolactam is improved.
Description
Technical Field
The invention relates to the technical field of petrochemical industry, in particular to a method for preparing caprolactam.
Background
Caprolactam is a key raw material for the production of nylon, nylon fibers and industrial cord products, and industrial caprolactam is generally prepared from cyclohexanone oxime. The cyclohexanone oxime is prepared into caprolactam by a gas phase Beckmann rearrangement reaction process catalyzed by sulfuric acid and liquid phase Beckmann rearrangement and MFI structure molecular sieve. The cyclohexanone oxime liquid-phase Beckmann rearrangement process consumes a large amount of sulfuric acid and ammonia water, and a large amount of low-value ammonium sulfate is produced as a byproduct, and meanwhile, equipment corrosion and environmental pollution are caused. The cyclohexanone oxime gas phase rearrangement does not produce byproduct ammonium sulfate, has the advantages of no equipment corrosion, green environmental protection and the like, and is widely focused and studied.
At present, some patents propose a fixed bed gas phase Beckmann rearrangement process with industrial application value, the process heats inert carrier gas containing solvent, then continuously introduces the inert carrier gas into an inlet provided with a multistage series fixed bed reactor, the cyclohexanone oxime is divided into a plurality of parts and added into each stage of series reactors in an equivalent way, and the carrier gas after reaction is recycled through a compressor. In the process, the conversion rate of the cyclohexanone oxime and the selectivity of the caprolactam are effectively improved, but the non-catalytic carbonization is serious in the feeding process of the cyclohexanone oxime, so that the surface of a catalyst is easy to coke and deactivate, further the risk of replacing the catalyst and stopping the device is caused, and the production efficiency of the caprolactam is reduced.
In view of this, the present invention has been made.
Disclosure of Invention
The invention mainly aims to provide a method for preparing caprolactam, which aims to solve the problem that in the existing method for preparing caprolactam by adopting a fixed bed to carry out a vapor phase Beckmann rearrangement reaction, cyclohexanone oxime is condensed and carbonized in the feeding process to cause coking on the surface of a catalyst.
In order to achieve the above object, according to one aspect of the present invention, there is provided a method for preparing caprolactam, comprising: conveying a gasified product containing cyclohexanone oxime and carrier gas into a reactor, wherein a catalyst is filled in the reactor, and the cyclohexanone oxime undergoes a gas-phase Beckmann rearrangement reaction under the catalysis of the catalyst to generate caprolactam;
wherein the reactor comprises n fixed bed layers which are sequentially communicated, each fixed bed layer is filled with a catalyst, n is more than or equal to 2 and less than or equal to 6, and n is a natural number.
Further, each fixed bed layer is vertically arranged in sequence from 1 to n, a first gasification inlet is arranged at the top of the first fixed bed in the reactor, a product outlet is arranged at the bottom of the nth fixed bed layer, and caprolactam is enriched at the bottom of the nth fixed bed layer and is discharged out of the reactor through the product outlet.
Further, the reactor is provided with a plurality of gasification feed inlets, the top parts of the second fixed bed layer and the nth fixed bed layer are provided with the second gasification feed inlets to the nth gasification feed inlets in a one-to-one correspondence manner, and preferably the mass of the gasification added through the first gasification inlet to the gasification added through the nth gasification inlet is sequentially reduced.
Further, the gasifies also comprise water, the mass ratio of water to cyclohexanone oxime is 0.1-5:10-80, preferably 0.2-2:20-60.
Further, the molar ratio of carrier gas to cyclohexanone oxime is 5-50:1, preferably 10-30:1.
Further, the carrier gas comprises at least one of nitrogen, argon, or carbon dioxide.
Further, the mass space velocity of cyclohexanone oxime is 0.2 to 10h -1, preferably 0.5 to 3h -1.
Further, the temperature of the vapor phase Beckmann rearrangement reaction is 300 to 400 ℃, preferably 330 to 380 ℃, and the pressure of the vapor phase Beckmann rearrangement reaction is 0 to 1MPaG, preferably 0 to 0.5MPaG.
Further, the catalyst is a silicon-based molecular sieve with an MFI structure, the silicon-based molecular sieve comprises doping elements, and the molar ratio of the doping elements to the silicon elements is 0-0.02:1.
Further, the doping element includes at least one of aluminum, titanium, boron, or iron.
Further, the method for preparing caprolactam further comprises a preparation process of the gasified substance, wherein the preparation process comprises the following steps: and gasifying the cyclohexanone oxime solution by using carrier gas under the heating condition to obtain a gasified substance.
Further, the gasification temperature is 120-200 ℃, preferably 140-180 ℃, and the pressure is 0-0.5MPaG, preferably 0.1-0.3MPaG.
Further, the concentration of the cyclohexanone oxime solution is 10wt% to 80wt%, preferably 20wt% to 60wt%.
Further, the cyclohexanone oxime solution comprises a solvent, preferably a C1-C6 fatty alcohol, and optionally water.
Further, the vaporization is effected in a falling film evaporator, a rising film evaporator or a wiped film evaporator.
By adopting the technical scheme, the cyclohexanone oxime is conveyed into the reactor with the plurality of communicated fixed bed layers to carry out the gas-phase Beckmann rearrangement reaction under the action of the carrier gas, so that the problems of condensation and carbonization of the cyclohexanone oxime in the feeding process can be effectively controlled, the coking of the catalyst can be effectively reduced, the service time of the catalyst is prolonged, the shutdown risk of the device caused by the replacement of the catalyst is further reduced, and the production efficiency of caprolactam is improved.
Drawings
The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the application. In the drawings:
Fig. 1 shows a schematic structure of a reactor employed in example 1 according to the present invention.
Wherein the above figures include the following reference numerals:
101. A first fixed bed layer; 102. a second fixed bed layer; 103. a third fixed bed layer; 104. a first vapor inlet; 105. a product outlet; 106. a second vapor feed port; 107. a third vapor feed port; 201. falling film evaporator.
Detailed Description
It should be noted that, without conflict, the embodiments of the present application and features of the embodiments may be combined with each other. The application will be described in detail below with reference to the drawings in connection with embodiments.
As analyzed by the background technology of the application, the existing fixed bed gas phase Beckmann rearrangement technology with industrial value respectively adds cyclohexanone oxime and inert carrier gas containing solvent into a multi-stage reactor, and the non-catalytic carbonization of the cyclohexanone oxime is serious in the feeding process of directly adding the cyclohexanone oxime into the reactor, so that the surface of the catalyst is easy to coke and deactivate, and further the technical problems of shortened service life of the catalyst and reduced caprolactam production efficiency caused by replacing the catalyst are caused. In order to solve the above problems, the present application provides a method for preparing caprolactam, the method comprising: conveying a gasified product containing cyclohexanone oxime and carrier gas into a reactor, wherein a catalyst is filled in the reactor, and the cyclohexanone oxime undergoes a gas-phase Beckmann rearrangement reaction under the catalysis of the catalyst to generate caprolactam; wherein the reactor comprises n fixed bed layers which are sequentially communicated, each fixed bed layer is filled with a catalyst, n is more than or equal to 2 and less than or equal to 6, and n is a natural number.
According to the method for preparing caprolactam, the cyclohexanone oxime is gasified by using the carrier gas to obtain the gasified product, then the cyclohexanone oxime is conveyed to the reactor with the plurality of communicated fixed bed layers to generate the gas-phase Beckmann rearrangement reaction under the carrier tape effect of the carrier gas in the gasified product, and the concentration of the cyclohexanone oxime at a high temperature is reduced due to the gasification effect of the carrier gas, so that the non-catalytic carbonization phenomenon in the independent feeding process of the cyclohexanone oxime is effectively controlled, the coking deactivation of a catalyst is effectively reduced, the service time of the catalyst is prolonged, the equipment stop risk caused by the replacement of the catalyst is further reduced, and the production efficiency of caprolactam is improved.
Typically, but not by way of limitation, n is, for example, 2, 3, 4, 5 or 6.
In order to further improve the preparation efficiency of the cyclohexanone oxime, the gasification compound containing the cyclohexanone oxime and the carrier gas is conveniently conveyed into the reactor, and in the reactor, the fixed bed layers are preferably vertically arranged in sequence from 1 to n, namely, the first fixed bed layer and the second fixed bed layer … … are sequentially arranged on the nth fixed bed layer, a first gasification compound inlet is arranged at the top of the first fixed bed layer, a product outlet is arranged at the bottom of the nth fixed bed layer, and caprolactam generated by the gas-phase Beckmann reaction of the cyclohexanone oxime is enriched at the bottom of the nth fixed bed layer and is discharged out of the reactor through the product outlet.
In the present application, the type of carrier gas is not limited, and any medium that does not react with cyclohexanone oxime and caprolactam may be used, including, but not limited to, a mixed gas of one or more of nitrogen, argon, or carbon dioxide.
In addition, in order to improve heat transfer efficiency and avoid local hot spots, in some embodiments of the present application, the reactor has a plurality of gasification feed inlets, and the second gasification feed inlets to the nth gasification feed inlets are disposed on top of the second fixed bed layer to the nth fixed bed layer in a one-to-one correspondence. The cyclohexanone oxime is added into a reactor in a batch mode by a feeding mode, so that the gasified matters are conveyed to each fixed bed layer in a segmented mode to carry out gas-phase Beckmann rearrangement reaction; and simultaneously, the 2 nd to n th fixed bed layers can utilize the heat released after the reaction of the previous fixed bed layer to preheat the gasifies added from the feed inlets at the top of each fixed bed layer to the reaction temperature and then enter the Beckmann rearrangement reaction of the present-stage fixed bed layer reaction, thereby being beneficial to saving energy and reducing emission, realizing the comprehensive utilization of energy, simultaneously taking into account the thermosensitive property of cyclohexanone oxime and the high reaction temperature required by the gas phase reaction, improving the heat transfer efficiency, reducing the temperature rise of hot spots in the reactor, further reducing the risk of coking and inactivation of the catalyst, effectively prolonging the service life of the catalyst and improving the selectivity of caprolactam.
In order to further improve the comprehensive utilization rate and the heat transfer efficiency of the resources, the mass of the gasifiers added through the first gasifiers inlet to the mass of the gasifiers added through the nth gasifiers inlet is preferably reduced in sequence, namely, the mass of the gasifiers added through the first gasifiers inlet is more than or equal to the mass of the gasifiers added through the second gasifiers inlet is more than or equal to … … and more than or equal to the mass of the gasifiers added through the nth gasifiers inlet.
In order to increase the activity of the catalyst, it is preferable that water is also included in the vapor. Since too high an amount of water may cause an increase in side reactions such as hydrolysis of cyclohexanone oxime, affecting the selectivity of caprolactam, it is preferable that the mass ratio of water to cyclohexanone oxime is 0.1-5:10-80, and especially when the mass ratio of water to cyclohexanone oxime is 0.2-2:20-60, the activity of the catalyst is higher, and the selectivity of caprolactam is further improved. The gasification compound of the application contains water, and the water enters along with the gasification compound in each level of fixed bed layer, thereby being more beneficial to controlling the water content in each level of fixed bed and further being more beneficial to improving the selectivity of caprolactam in each level of fixed bed layer.
In order to further reduce the risk of coking and deactivation of the catalyst and improve the stability of the cyclohexanone oxime feeding process, preferably, the molar ratio of carrier gas to cyclohexanone oxime in the gasification is 5-50:1, and especially when the molar ratio of carrier gas to cyclohexanone oxime in the gasification is 10-30:1, the risk of coking and deactivation of the catalyst is easier to reduce and the stability of the cyclohexanone oxime feeding process is improved.
Typically, but not by way of limitation, the molar ratio of carrier gas to cyclohexanone oxime in the gasifier is, for example, 5:1, 10:1, 15:1, 20:1, 25:1, 30:1, 35:1, 40:1, 45:1 or 50:1, and the mass ratio of water to cyclohexanone oxime is, for example, 0.1:10、0.1:20、0.1:50、0.1:80、0.2:10、0.2:20、0.2:40、0.2:60、0.2:80、0.5:10、0.5:20、0.5:40、0.5:60、1:20、1:60、1:80、2:20、2:40、2:80、3:10、3:20、3:50 or 3:80.
In order to increase the conversion of cyclohexanone oxime and the selectivity of caprolactam, it is preferred that the mass space velocity of cyclohexanone oxime in the reactor is in the range of 0.2 to 10h -1, especially when the mass space velocity of cyclohexanone oxime is in the range of 0.5 to 3h -1, the conversion of cyclohexanone oxime and the selectivity of caprolactam are further increased.
The mass space velocity of cyclohexanone oxime in the above-mentioned reactor means the ratio of the mass of cyclohexanone oxime fed into the reactor per hour to the total catalyst in the reactor.
Typically, but not by way of limitation, the mass space velocity of cyclohexanone oxime in the reactor is, for example, 0.2h-1、0.5h-1、0.8h-1、1h-1、1.5h-1、2h-1、2.5h-1、3h-1、3.5h-1、4h-1、4.5h-1 5h-1、6h-1、7h-1、8h-1、9h-1 or 10h -1.
In order to improve the efficiency of the vapor phase Beckmann rearrangement reaction of the cyclohexanone oxime, it is preferable that the temperature of the vapor phase Beckmann rearrangement reaction is 300 to 400℃and the pressure is 0 to 0.5MPaG, and especially when the temperature of the vapor phase Beckmann rearrangement reaction is 330 to 380℃and the pressure is 0 to 0.3MPaG, the efficiency of the vapor phase Beckmann rearrangement reaction of the cyclohexanone oxime is higher.
Typically, but not by way of limitation, the temperature of the gas phase Beckmann rearrangement reaction is, for example, 300 ℃, 320 ℃, 350 ℃, 380 ℃ or 400 ℃, and the pressure is, for example, 0MPa, 0.1MPa, 0.2MPa, 0.3MPa, 0.4MPa or 0.5MPa.
In order to increase the reaction efficiency of the vapor phase beckmann rearrangement reaction, in some embodiments of the present application, a silicon-based molecular sieve having an MFI structure is used as a catalyst. In order to further improve the catalytic efficiency of the catalyst, the molecular sieve can comprise doping elements, and the molar ratio of the doping elements to silicon is preferably 0-0.02:1, so that the efficiency of the gas phase Beckmann rearrangement reaction is higher.
The doping elements are not limited in kind, and any element capable of improving the catalytic efficiency of the silicon-based molecular sieve may be used, and commonly used doping elements include, but are not limited to, one or more of aluminum, titanium, boron or iron.
In order to increase the caprolactam yield, the above catalyst is preferably packed in a fully fixed bed.
Typically, but not by way of limitation, the mole ratio of doping element to silicon is, for example, 0.005:1, 0.01:1, 0.015:1, or 0.02:1.
In some embodiments of the present application, the above-described method for producing caprolactam further comprises a process for producing a vapor, the process comprising:
The cyclohexanone oxime solution is gasified by using carrier gas under heating condition to obtain the gasified product, and the preferable gasification condition is: the temperature is 120-200 ℃, the pressure is 0-0.5MPa, so that the gasification efficiency of the cyclohexanone oxime is improved, and particularly, when the temperature is 140-180 ℃, the pressure is 0-0.3MPaG, the gasification efficiency of the cyclohexanone oxime is higher.
Typically, but not by way of limitation, the temperature of gasification is, for example, 100 ℃, 120 ℃, 150 ℃, 180 ℃, or 200 ℃, and the pressure is, for example, 0MPa, 0.1MPa, 0.2MPa, 0.3MPa, 0.4MPa, or 0.5 MPa.
The apparatus for carrying out the above vaporization is not limited, and any apparatus capable of carrying out the vaporization of the solution may be used, and common vaporization apparatuses such as a falling film evaporator, a rising film evaporator or a wiped film evaporator may be used for vaporizing the cyclohexanone oxime solution.
The above-mentioned cyclohexanone oxime solution for preparing a vapor is mainly prepared by dissolving cyclohexanone oxime in a solvent, preferably a C1-C6 fatty alcohol, so as to facilitate the improvement of the solubility of cyclohexanone oxime. The C1-C6 fatty alcohols may be either straight chain or branched chain fatty alcohols, for example: one or more of methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol or tert-butanol. Preferably, the cyclohexanone oxime solution is gasified more advantageously when the mass concentration of the cyclohexanone oxime is 10% to 80%, and particularly when the mass concentration of the cyclohexanone oxime is 20% to 60%, the gasification efficiency is higher.
Preferably, the water in the above-mentioned gasified product is carried in from the cyclohexanone oxime solution, and the mass content of water in the cyclohexanone oxime solution is preferably 0.1 to 5% to reduce side reactions while improving the catalyst activity, and particularly when the mass content of water is further preferably 0.2 to 2%, the conversion rate of cyclohexanone oxime and the selectivity of caprolactam are higher when the gasification of the cyclohexanone oxime solution is followed by the gas-phase Beckmann rearrangement reaction with the gasified product formed by the carrier gas.
Typically, but not by way of limitation, the cyclohexanone oxime solution has a water mass content of e.g. 0.1%, 0.2%, 0.5%, 0.8%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5% or 4% and a cyclohexanone oxime mass concentration of e.g. 10%, 20%, 30%, 40%, 50%, 60%, 70% or 80%.
The advantageous effects of the present application will be further described below with reference to examples and comparative examples. In the examples below, a 3% decrease in one of the cyclohexanone oxime conversion and caprolactam selectivity relative to the corresponding value of the reaction plateau is regarded as catalyst deactivation, which is the end of catalyst life.
The following "%" is abbreviated "wt%".
Example 1
The embodiment provides a method for preparing caprolactam, wherein the process flow chart is shown in fig. 1, and the method comprises the following steps:
(1) Mixing and gasifying cyclohexanone oxime methanol solution with concentration of 20% and water content of 1% and nitrogen in a falling film evaporator 201 to obtain a gasified substance; wherein the gasification temperature is 175 ℃, the pressure is 0.25MPaG, and the molar ratio of nitrogen to cyclohexanone oxime is 15:1.
(2) Dividing the gasified matters into a first gasified matters, a second gasified matters and a third gasified matters, wherein the mass ratio of the three gasified matters is 50:25:25, the three gasified matters are respectively introduced into a reactor for gas-phase Beckmann rearrangement reaction, the mass airspeed of cyclohexanone oxime is 1h -1, the temperature in the reactor is 360 ℃, the pressure is 0.25MPa, as shown in figure 1, the reactor comprises a first fixed bed layer 101, a second fixed bed layer 102 and a third fixed bed layer 103 which are sequentially communicated from top to bottom and are vertically arranged, the three fixed bed layers are equally filled with an MFI structure high silicon molecular sieve catalyst doped with titanium elements (the molar ratio of titanium to silicon is 0.001), the top of the first fixed bed layer to the top of the third fixed layer are respectively provided with a first gasified matter inlet 104, a second gasified matter feed inlet 106 and a third gasified matter feed inlet 107 in a one-to-one correspondence mode, the bottom of the third fixed bed layer is provided with a product outlet 105, the first gasified matters are added into the first fixed bed layer 101 through the first fixed bed layer from top to bottom, the first gasified products are generated through the first fixed bed layer 101, then the first gasified products are generated through the first fixed bed layer 101 and are mixed with the third gasified products generated through the third fixed bed layer from the second fixed bed layer 103 and are discharged into the third gasified products through the third fixed bed layer from the third layer 106.
Example 2
The embodiment provides a method for preparing caprolactam, which is different from embodiment 1 in that in step (2), the gasification is divided into a first gasification and a second gasification, the mass ratio of the first gasification to the second gasification is 60:40, the reactor comprises a first fixed bed layer and a second fixed bed layer, the equal amount of catalyst filled in the two fixed bed layers is the same as embodiment 1, a first gasification inlet is arranged at the top of the first fixed bed layer, a second gasification feed port is arranged at the top of the second fixed bed layer, the first gasification is added into the first fixed bed layer from the first gasification inlet to react to generate a first reaction product, the first reaction product is mixed with the second gasification added from the second gasification feed port to react to generate a second reaction product, and the second reaction product is discharged from a product outlet at the bottom of the second fixed bed layer and collected.
Example 3
The embodiment provides a method for preparing caprolactam, which is different from embodiment 1 in that in step (2), the gasification is divided into a first gasification, a second gasification, a third gasification and a fourth gasification, the mass ratio of the four is 45:25:15:15, the reactor comprises a first fixed bed layer, a second fixed bed layer, a third fixed bed layer and a fourth fixed bed layer which are sequentially arranged from top to bottom, the catalysts which are equally loaded in the four fixed bed layers are the same as embodiment 1, a first gasification inlet, a second gasification feed port, a third gasification feed port and a fourth gasification feed port are sequentially arranged from top to bottom of the first to fourth fixed bed layers, the fourth gasification is added into the first fixed bed layer from the first gasification inlet to generate a first reaction product, the first reaction product is mixed with the second gasification added from the second gasification feed port and then enters the fourth fixed bed layer to generate a second reaction product, the second reaction product is mixed with the third gasification added from the third gasification feed port and enters the fourth fixed bed layer from the fourth fixed bed layer to generate a fourth reaction product, and the fourth gasification product is discharged from the fourth gasification feed port to generate a fourth reaction product after the fourth gasification feed port enters the fourth fixed bed layer from the fourth gasification feed port to generate a fourth reaction product.
Example 4
The present embodiment provides a method for preparing caprolactam, which is different from embodiment 1 in that in step (2), the gasification is divided into a first gasification, a second gasification, a third gasification, a fourth gasification and a fifth gasification, the mass ratio of the fifth gasification is 40:20:15:15:10, and the reactor comprises a first fixed bed layer, a second fixed bed layer, a third fixed bed layer, a fourth fixed bed layer and a fifth fixed bed layer which are sequentially arranged from top to bottom, and the five fixed bed layers are equally filled with the catalyst in embodiment 1. The five fixed bed layers are sequentially provided with a first gasification object inlet, a second gasification object feeding port, a third gasification object feeding port, a fourth gasification object feeding port and a fifth gasification object feeding port in a one-to-one correspondence mode from the top of one to the top of five, the first gasification object is added into the first fixed bed layer from the first gasification object inlet to react to generate a first reaction product, the first reaction product is mixed with the second gasification object added from the second gasification object feeding port to enter the second fixed bed layer to react to generate a second reaction product, the second reaction product is mixed with the third gasification object added from the third gasification object feeding port to enter the third fixed bed layer to react to generate a third reaction product, the third reaction product is mixed with the fourth gasification object added from the fourth gasification object feeding port to enter the fourth fixed bed layer to react to generate a fourth reaction product, the fourth reaction product is mixed with the fifth gasification object added from the fifth feeding port to enter the fifth fixed bed to react to generate a fifth reaction product, and the fifth reaction product is discharged from a product outlet at the bottom of the fifth fixed bed to react to generate a third reaction product, and the fifth reaction product is collected.
Example 5
The present embodiment provides a method for preparing caprolactam, which is different from embodiment 1 in that in step (2), the gasifiable is divided into a first gasifiable, a second gasifiable, a third gasifiable, a fourth gasifiable, a fifth gasifiable and a sixth gasifiable, the mass ratio of the sixth gasifiable is 35:20:15:10:5, and the reactor comprises a first fixed bed layer, a second fixed bed layer, a third fixed bed layer, a fourth fixed bed layer, a fifth fixed bed layer and a sixth fixed bed layer which are sequentially arranged from top to bottom, the catalyst of equal amount of the sixth fixed bed layer is the same as embodiment 1, the sixth solid bed layer is sequentially provided with a first gasifiable inlet, a second gasifiable feed inlet, a third gasifiable feed inlet, a fourth gasifiable feed inlet, a fifth gasifiable feed inlet and a sixth gasifiable feed inlet from first fixed bed layer to generate a first reaction product, the second reaction product is added into the first fixed bed layer from the first fixed bed layer, the second reaction product is added into the fifth fixed bed layer from the second fixed bed layer to the third fixed bed layer, the fifth reaction product is added into the fifth reaction product is mixed with the fifth gasifiable product is generated from the fifth reaction product, the fifth reaction product is added into the fourth fixed bed layer from the fifth reaction layer, and the second reaction product is added into the fifth reaction product is formed from the fourth reaction product, and the gasification product is added into the fourth reaction product is formed from the fourth gasification feed inlet, and the third gasification mixture is formed from the fourth gasification mixture after the fourth gasification is added into the fourth gasification product is added into the fourth gasification mixture is formed from the top and the top is formed into the mixture, the sixth reaction product exits the reactor at a product outlet at the bottom of the sixth fixed bed and is collected.
Example 6
The difference between this example and example 1 is that the catalyst is an MFI structure high silicon molecular sieve doped with aluminum element, and the molar ratio of titanium to silicon is 0.001.
Example 7
The difference between this example and example 1 is that the catalyst is a boron-doped MFI structure high silicon molecular sieve, and the molar ratio of boron to silicon is 0.001.
Example 8
The difference between this example and example 1 is that the catalyst is a high silicon molecular sieve of MFI structure doped with iron element, and the molar ratio of iron to silicon is 0.001.
Example 9
This example differs from example 1 in that the catalyst is an MFI structure all-silica molecular sieve.
Example 10
The difference between this example and example 1 is that the catalyst is an MFI structure all-silicon molecular sieve doped with titanium element, and the molar ratio of titanium to silicon is 2.
Example 11
This example differs from example 1 in that the gasification temperature in step (1) is 120 ℃.
Example 12
This example differs from example 1 in that the gasification temperature in step (1) is 160 ℃.
Example 13
This example differs from example 1 in that the gasification temperature in step (1) is 200 ℃.
Example 14
This example differs from example 1 in that the gasification pressure in step (1) was 0MPaG, and in step (2), the pressure in the reactor was 0MPaG.
Example 15
This example differs from example 1 in that the gasification pressure in step (1) was 0.3MPaG and the pressure in the reactor in step (2) was 0.3MPaG.
Example 16
This example differs from example 1 in that the gasification pressure in step (1) was 0.5MPaG and the pressure in the reactor in step (2) was 0.5MPaG.
Example 17
This example differs from example 1 in that a rising film evaporator is used instead of a falling film evaporator in step (1).
Example 18
This example is different from example 1 in that a wiped film evaporator is used instead of a falling film evaporator in step (1), and the mass concentration of the cyclohexanone oxime methanol solution used is 10% and the water content is 1%.
Example 19
This example differs from example 1 in that the concentration of the cyclohexanone oxime methanol solution in step (1) is 40%.
Example 20
This example differs from example 1 in that the concentration of the cyclohexanone oxime methanol solution in step (1) is 60%.
Example 21
This example differs from example 1 in that in step (2), the temperature in the reactor was 300 ℃.
Example 22
This example differs from example 1 in that in step (2) the temperature in the reactor was 400 ℃.
Example 23
This example differs from example 1 in that the water content of the cyclohexanone oxime methanol solution in step (1) is 0.1%.
Example 24
This example differs from example 1 in that the water content of the cyclohexanone oxime methanol solution in step (1) is 1.5%.
Example 25
This example differs from example 1 in that the water content of the cyclohexanone oxime methanol solution in step (1) is 5%.
Example 26
This example differs from example 1 in that the mass space velocity of cyclohexanone oxime in step (2) is 0.5h -1.
Example 27
This example differs from example 1 in that the mass space velocity of cyclohexanone oxime in step (2) is 1.5h -1.
Example 28
This example differs from example 1 in that the mass space velocity of cyclohexanone oxime in step (2) is 3.0h -1.
Example 29
This example differs from example 1 in that the molar ratio of nitrogen to cyclohexanone oxime in step (1) is 10:1.
Example 30
This example differs from example 1 in that the molar ratio of nitrogen to cyclohexanone oxime in step (1) is 20:1.
Example 31
This example differs from example 1 in that the molar ratio of nitrogen to cyclohexanone oxime in step (1) is 30:1.
Example 32
This example differs from example 1 in that the cyclohexanone oxime ethanol solution is used in step (1) instead of the cyclohexanone oxime methanol solution, and the concentration and the water content are the same as those in example 1.
Example 33
This example is different from example 1 in that in step (1), a cyclohexanone oxime propanol solution is used instead of a cyclohexanone oxime methanol solution, and the concentration and water content are the same as those in example 1.
Example 34
This example differs from example 1 in that in step (1), the water content of the cyclohexanone oxime methanol solution is 0.2%.
Example 35
This example differs from example 1 in that in step (1), the water content of the cyclohexanone oxime methanol solution is 2%.
Example 36
This example differs from example 1 in that in step (1), the cyclohexanone oxime methanol solution contains no water.
Example 37
This example differs from example 1 in that in step (1), the water content of the cyclohexanone oxime methanol solution is 10%.
Example 38
This example differs from example 1 in that the molar ratio of nitrogen to cyclohexanone oxime in step (1) is 5:1.
Example 39
This example differs from example 1 in that the molar ratio of nitrogen to cyclohexanone oxime in step (1) is 50:1.
Example 40
This example differs from example 1 in that the molar ratio of nitrogen to cyclohexanone oxime in step (1) is 4:1, and the mass concentration of the cyclohexanone oxime methanol solution is 80%, and the water content is 1%.
Example 41
This example differs from example 1 in that the molar ratio of nitrogen to cyclohexanone oxime in step (1) is 80:1.
Example 42
This example differs from example 1 in that the mass space velocity of cyclohexanone oxime in step (2) is 0.2h -1.
Example 43
This example differs from example 1 in that the mass space velocity of cyclohexanone oxime in step (2) is 10h -1.
Example 44
This example differs from example 1 in that the mass space velocity of cyclohexanone oxime in step (2) is 0.1h -1.
Example 45
This example differs from example 1 in that the mass space velocity of cyclohexanone oxime in step (2) is 20h -1.
Example 46
The difference between this embodiment and embodiment 1 is that in step (2), the top of the second fixed bed layer and the top of the third fixed bed layer are provided with feed inlets, the gasified matters are introduced into the reactor from the first gasified matters inlet at the top of the first fixed bed layer, and the reaction products are obtained by sequentially passing through the first fixed bed layer, the second fixed bed layer and the third fixed bed layer, and the reaction products are discharged from the reactor from the product at the bottom of the third fixed bed layer and collected.
Comparative example 1
This comparative example differs from example 1 in that in step (1) no cyclohexanone oxime was added to the vapor, in step (2) the vapor was introduced into the reactor from the top of the first fixed bed, the liquid cyclohexanone oxime was divided into three equal portions, and three portions of cyclohexanone oxime were added to the reactor from the first vapor inlet, the second vapor feed port and the third vapor feed port, respectively.
Comparative example 2
This comparative example is different from example 1 in that in step (1), no cyclohexanone oxime was added to the gasified product, and in step (2), the gasified product was fed into the first fixed bed layer, the second fixed bed layer and the third fixed bed layer in this order from the top of the first fixed bed layer, the liquid cyclohexanone oxime was divided into three portions of first cyclohexanone oxime, second cyclohexanone oxime and third cyclohexanone oxime, respectively, in a mass ratio of 50:25:25, and the first cyclohexanone oxime, the second cyclohexanone oxime and the third cyclohexanone oxime were fed into the reactor from the first gas inlet, the second gas feed port and the third gas feed port, respectively.
Test examples
The reaction products collected in the above examples and comparative examples were weighed and sampled respectively for analysis, and the conversion of cyclohexanone oxime and caprolactam selectivity were calculated, and the results are shown in Table 1 below. Wherein, the reaction product adopts an area normalization method to measure the content in the sample through gas chromatography; the calculation method of cyclohexanone oxime conversion and caprolactam selectivity is as follows:
Cyclohexanone oxime conversion (%) = { (a-B)/a } ×100%;
selectivity of caprolactam (%) = { C/(a-B) } ×100%
A is the molar content of cyclohexanone oxime in the gasified substance before reaction;
B is the molar content of cyclohexanone oxime in the reaction liquid after the reaction;
C is the increase of caprolactam mole content in the reaction liquid after the reaction.
TABLE 1 cyclohexanone oxime conversion and caprolactam selectivity data sheet
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From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects: the cyclohexanone oxime is conveyed into a reactor with a plurality of communicated fixed bed layers to carry out gas-phase Beckmann rearrangement reaction under the carrier effect of carrier gas, so that the problems of condensation and carbonization of the cyclohexanone oxime in the feeding process can be effectively controlled, the coking of the catalyst can be effectively reduced, the service time of the catalyst is prolonged, the device stop risk caused by replacing the catalyst is further reduced, and the production efficiency of caprolactam is improved.
The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (8)
1. A process for preparing caprolactam comprising: conveying a gasified product containing cyclohexanone oxime and carrier gas into a reactor, wherein a catalyst is filled in the reactor, and the cyclohexanone oxime undergoes a gas-phase Beckmann rearrangement reaction under the catalysis of the catalyst to generate caprolactam;
The reactor comprises n fixed bed layers which are sequentially communicated, wherein each fixed bed layer is filled with the catalyst, and n is 3 or 6;
the molar ratio of the carrier gas to the cyclohexanone oxime is 15:1;
the mass airspeed of the cyclohexanone oxime is 0.2-10h -1;
the temperature of the gas-phase Beckmann rearrangement reaction is 360 ℃, and the pressure of the gas-phase Beckmann rearrangement reaction is 0-0.3MpaG;
The catalyst is a silicon-based molecular sieve with an MFI structure, the silicon-based molecular sieve comprises doping elements, the molar ratio of the doping elements to the silicon elements is 0-0.02:1, the catalyst does not contain 0, and the doping elements comprise at least one of aluminum, titanium and boron;
The method further includes a process for preparing the vapor, the process comprising: gasifying the cyclohexanone oxime solution by using the carrier gas under the heating condition to obtain the gasified substance; the gasification temperature is 175 ℃, and the gasification pressure is 0-0.3 MPaG;
The concentration of the cyclohexanone oxime solution is 20-60 wt%; the cyclohexanone oxime solution comprises solvent and water, and has a water content of 1wt%.
2. The method for producing caprolactam according to claim 1, wherein each of the fixed bed layers is vertically arranged in order from 1 to n, a first gasification inlet is arranged at the top of the first fixed bed layer, a product outlet is arranged at the bottom of the nth fixed bed layer, and caprolactam is enriched at the bottom of the nth fixed bed layer and is discharged from the reactor through the product outlet.
3. The method for preparing caprolactam according to claim 2, wherein the reactor is provided with a plurality of gasification feed inlets, and the second gasification feed inlets to the nth gasification feed inlets are arranged on top of the second fixed bed layer to the nth fixed bed layer in a one-to-one correspondence.
4. A process for preparing caprolactam according to claim 3, wherein the mass of the gasifies added through the first gasifies inlet to the gasifies added through the nth gasifies inlet decreases in sequence.
5. A process for preparing caprolactam as claimed in any one of claims 1 to 4, wherein,
The carrier gas includes at least one of nitrogen, argon, or carbon dioxide.
6. Process for preparing caprolactam according to any one of claims 1 to 4, characterized in that the mass space velocity of the cyclohexanone oxime is 0.5-3h -1.
7. The method for preparing caprolactam according to claim 1, wherein the solvent is a C1-C6 aliphatic alcohol.
8. The process for preparing caprolactam according to claim 1, wherein the gasification is effected in a falling film evaporator, a rising film evaporator or a wiped film evaporator.
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| CN1621405A (en) * | 2003-11-28 | 2005-06-01 | 中国石油化工股份有限公司 | Process for preparing caprolactam by cyclohexanone-oxime gas phase rearrangement |
| CN101434569A (en) * | 2007-11-15 | 2009-05-20 | 中国石油化工股份有限公司 | Method and equipment for preparing caprolactam from cyclohexanone oxime |
| CN103889950A (en) * | 2011-10-17 | 2014-06-25 | 住友化学株式会社 | Production method for epsilon-caprolactam |
| WO2016148200A1 (en) * | 2015-03-17 | 2016-09-22 | 住友化学株式会社 | METHOD FOR PRODUCING ε-CAPROLACTAM |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN1621405A (en) * | 2003-11-28 | 2005-06-01 | 中国石油化工股份有限公司 | Process for preparing caprolactam by cyclohexanone-oxime gas phase rearrangement |
| CN101434569A (en) * | 2007-11-15 | 2009-05-20 | 中国石油化工股份有限公司 | Method and equipment for preparing caprolactam from cyclohexanone oxime |
| CN103889950A (en) * | 2011-10-17 | 2014-06-25 | 住友化学株式会社 | Production method for epsilon-caprolactam |
| WO2016148200A1 (en) * | 2015-03-17 | 2016-09-22 | 住友化学株式会社 | METHOD FOR PRODUCING ε-CAPROLACTAM |
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