CN117185895A - Method and system for producing xylene - Google Patents
Method and system for producing xylene Download PDFInfo
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- CN117185895A CN117185895A CN202210603355.4A CN202210603355A CN117185895A CN 117185895 A CN117185895 A CN 117185895A CN 202210603355 A CN202210603355 A CN 202210603355A CN 117185895 A CN117185895 A CN 117185895A
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- transalkylation
- benzene
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- alkane
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- CTQNGGLPUBDAKN-UHFFFAOYSA-N O-Xylene Chemical compound CC1=CC=CC=C1C CTQNGGLPUBDAKN-UHFFFAOYSA-N 0.000 title claims abstract description 70
- 238000000034 method Methods 0.000 title claims abstract description 62
- 239000008096 xylene Substances 0.000 title claims abstract description 52
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 claims abstract description 260
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 claims abstract description 181
- 238000005804 alkylation reaction Methods 0.000 claims abstract description 121
- 238000010555 transalkylation reaction Methods 0.000 claims abstract description 102
- 150000001335 aliphatic alkanes Chemical class 0.000 claims abstract description 80
- 230000029936 alkylation Effects 0.000 claims abstract description 60
- 150000004945 aromatic hydrocarbons Chemical class 0.000 claims abstract description 60
- 239000001257 hydrogen Substances 0.000 claims abstract description 44
- 229910052739 hydrogen Inorganic materials 0.000 claims abstract description 44
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims abstract description 40
- 238000005984 hydrogenation reaction Methods 0.000 claims abstract description 19
- 239000002994 raw material Substances 0.000 claims abstract description 13
- 230000000694 effects Effects 0.000 claims abstract description 6
- 239000003054 catalyst Substances 0.000 claims description 72
- 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 55
- 239000002808 molecular sieve Substances 0.000 claims description 53
- 239000003921 oil Substances 0.000 claims description 41
- 239000000463 material Substances 0.000 claims description 25
- 239000011230 binding agent Substances 0.000 claims description 23
- 238000005194 fractionation Methods 0.000 claims description 23
- 229910052751 metal Inorganic materials 0.000 claims description 23
- 239000002184 metal Substances 0.000 claims description 23
- WKBOTKDWSSQWDR-UHFFFAOYSA-N Bromine atom Chemical compound [Br] WKBOTKDWSSQWDR-UHFFFAOYSA-N 0.000 claims description 15
- GDTBXPJZTBHREO-UHFFFAOYSA-N bromine Substances BrBr GDTBXPJZTBHREO-UHFFFAOYSA-N 0.000 claims description 15
- 229910052794 bromium Inorganic materials 0.000 claims description 15
- 150000003738 xylenes Chemical class 0.000 claims description 13
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 12
- 229910021536 Zeolite Inorganic materials 0.000 claims description 12
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 claims description 12
- 239000010457 zeolite Substances 0.000 claims description 12
- 229930195735 unsaturated hydrocarbon Natural products 0.000 claims description 11
- 239000007791 liquid phase Substances 0.000 claims description 10
- 238000004821 distillation Methods 0.000 claims description 9
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- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 8
- 238000004891 communication Methods 0.000 claims description 8
- 238000004064 recycling Methods 0.000 claims description 8
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- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 3
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- 238000006243 chemical reaction Methods 0.000 abstract description 37
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- 238000001125 extrusion Methods 0.000 description 7
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 6
- 241000219782 Sesbania Species 0.000 description 6
- 150000001336 alkenes Chemical class 0.000 description 6
- 230000008901 benefit Effects 0.000 description 6
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 description 6
- 229910017604 nitric acid Inorganic materials 0.000 description 6
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- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 description 5
- 238000002360 preparation method Methods 0.000 description 5
- URLKBWYHVLBVBO-UHFFFAOYSA-N Para-Xylene Chemical group CC1=CC=C(C)C=C1 URLKBWYHVLBVBO-UHFFFAOYSA-N 0.000 description 4
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 4
- 125000003118 aryl group Chemical group 0.000 description 4
- 125000004432 carbon atom Chemical group C* 0.000 description 4
- 239000012018 catalyst precursor Substances 0.000 description 4
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- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 3
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 3
- 239000005977 Ethylene Substances 0.000 description 3
- IMNFDUFMRHMDMM-UHFFFAOYSA-N N-Heptane Chemical compound CCCCCCC IMNFDUFMRHMDMM-UHFFFAOYSA-N 0.000 description 3
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 description 3
- 125000000217 alkyl group Chemical group 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 3
- 150000001924 cycloalkanes Chemical class 0.000 description 3
- 229930195733 hydrocarbon Natural products 0.000 description 3
- 150000002430 hydrocarbons Chemical class 0.000 description 3
- 150000002431 hydrogen Chemical class 0.000 description 3
- JRZJOMJEPLMPRA-UHFFFAOYSA-N olefin Natural products CCCCCCCC=C JRZJOMJEPLMPRA-UHFFFAOYSA-N 0.000 description 3
- 238000002407 reforming Methods 0.000 description 3
- FYGHSUNMUKGBRK-UHFFFAOYSA-N 1,2,3-trimethylbenzene Chemical compound CC1=CC=CC(C)=C1C FYGHSUNMUKGBRK-UHFFFAOYSA-N 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- IFTRQJLVEBNKJK-UHFFFAOYSA-N Ethylcyclopentane Chemical compound CCC1CCCC1 IFTRQJLVEBNKJK-UHFFFAOYSA-N 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- OFBQJSOFQDEBGM-UHFFFAOYSA-N Pentane Chemical compound CCCCC OFBQJSOFQDEBGM-UHFFFAOYSA-N 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- KKEYFWRCBNTPAC-UHFFFAOYSA-N Terephthalic acid Chemical compound OC(=O)C1=CC=C(C(O)=O)C=C1 KKEYFWRCBNTPAC-UHFFFAOYSA-N 0.000 description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- 150000004996 alkyl benzenes Chemical class 0.000 description 2
- 238000009835 boiling Methods 0.000 description 2
- 238000001354 calcination Methods 0.000 description 2
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- 229910052799 carbon Inorganic materials 0.000 description 2
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- 238000005516 engineering process Methods 0.000 description 2
- IVSZLXZYQVIEFR-UHFFFAOYSA-N m-xylene Chemical group CC1=CC=CC(C)=C1 IVSZLXZYQVIEFR-UHFFFAOYSA-N 0.000 description 2
- UAEPNZWRGJTJPN-UHFFFAOYSA-N methylcyclohexane Chemical compound CC1CCCCC1 UAEPNZWRGJTJPN-UHFFFAOYSA-N 0.000 description 2
- ZGEGCLOFRBLKSE-UHFFFAOYSA-N methylene hexane Natural products CCCCCC=C ZGEGCLOFRBLKSE-UHFFFAOYSA-N 0.000 description 2
- 238000002715 modification method Methods 0.000 description 2
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- TVMXDCGIABBOFY-UHFFFAOYSA-N octane Chemical compound CCCCCCCC TVMXDCGIABBOFY-UHFFFAOYSA-N 0.000 description 2
- UOHMMEJUHBCKEE-UHFFFAOYSA-N prehnitene Chemical compound CC1=CC=C(C)C(C)=C1C UOHMMEJUHBCKEE-UHFFFAOYSA-N 0.000 description 2
- 239000001294 propane Substances 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
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- IRUDSQHLKGNCGF-UHFFFAOYSA-N 2-methylhex-1-ene Chemical compound CCCCC(C)=C IRUDSQHLKGNCGF-UHFFFAOYSA-N 0.000 description 1
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- 229920001353 Dextrin Polymers 0.000 description 1
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- OTMSDBZUPAUEDD-UHFFFAOYSA-N Ethane Chemical compound CC OTMSDBZUPAUEDD-UHFFFAOYSA-N 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- APUPEJJSWDHEBO-UHFFFAOYSA-P ammonium molybdate Chemical compound [NH4+].[NH4+].[O-][Mo]([O-])(=O)=O APUPEJJSWDHEBO-UHFFFAOYSA-P 0.000 description 1
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- GYNNXHKOJHMOHS-UHFFFAOYSA-N methyl-cycloheptane Natural products CC1CCCCCC1 GYNNXHKOJHMOHS-UHFFFAOYSA-N 0.000 description 1
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Abstract
The invention relates to the technical field of petrochemical industry and discloses a method and a system for generating dimethylbenzene. The method comprises the following steps: an alkylation reaction and a transalkylation reaction which are sequentially carried out; under alkylation reaction conditions, alkane is contacted with benzene and hydrogen to carry out alkylation reaction; contacting at least c9+ heavy aromatics from alkylation, toluene, and hydrogen under transalkylation reaction conditions to effect transalkylation; wherein the alkane is raffinate oil and/or raffinate oil after hydrogenation; wherein the weight ratio of benzene to alkane is 1-9:1; wherein the weight ratio of the C9+ heavy aromatic hydrocarbon to the toluene is 1-5:1. The method takes non-aromatic hydrocarbon (C5-C9), in particular non-aromatic hydrocarbon and C9+ heavy aromatic hydrocarbon which are byproducts of catalytic reforming or steam cracking as raw materials, combines alkylation reaction and transalkylation reaction, and has the characteristics of high non-aromatic hydrocarbon conversion rate and high xylene yield.
Description
Technical Field
The invention relates to the technical field of petrochemical industry, in particular to a method and a system for producing dimethylbenzene.
Background
Xylene is the most important part of the basic organic chemical raw material, wherein paraxylene is the main raw material for producing terephthalic acid, polyester fiber and engineering plastics. Currently, the production of xylenes is mainly derived from the reforming process of a refinery and from byproducts of the steam cracking of naphtha to olefins. In the whole production process, a large amount of non-aromatic hydrocarbon (C5-C9) and C9+ heavy aromatic hydrocarbon byproducts exist, and the additional value is low, the application is narrow and the source is wide. Currently, reforming byproduct non-aromatic hydrocarbons are widely used in the production of various types of solvent oils (e.g., no. 6 solvent oil), and a small amount is used as blending gasoline and olefin cracking feedstock. However, the economic benefits of processing and utilization are poor due to the disadvantages of low octane number (RON), low boiling range, low ethylene yield, etc. On the other hand, with the construction and energy expansion transformation of aromatic hydrocarbon combination units and large-scale ethylene units in China, byproduct C9+ heavy aromatic hydrocarbons are more and more, and the method is mainly applied to the extraction of trimethylbenzene and tetramethylbenzene monomers and gasoline blending components at present. However, due to the complex components, the boiling point difference is small, the separation difficulty is large, and the aromatic hydrocarbon content in the national gasoline standard is further limited.
Patent application CN106367116a discloses a method for preparing light aromatic hydrocarbons by using reformed raffinate oil, which converts the reformed raffinate oil into light aromatic hydrocarbons, the yield of the light aromatic hydrocarbons can reach 50-60%, and meanwhile, the octane number (RON) 87-90 gasoline blending component is a byproduct. However, the method still has the problems of high energy consumption, low xylene yield and the like. Patent application CN104557428A discloses a method for increasing yield of dimethylbenzene by alkyl transfer and alkylation of aromatic hydrocarbon, but has the problems of high dry gas yield, low raw material conversion rate and the like. Patent application CN106083512a discloses an apparatus and a process for the preparation of benzene and xylenes from toluene and heavy aromatics, but with a limited methyl content and the production of large amounts of benzene, corresponding to refineries not requiring large amounts of benzene, without any further treatment. Thus, there is a need to develop a process that can directly convert non-aromatic (C5-C9) and c9+ heavy aromatics into high value added products.
Disclosure of Invention
The invention aims to solve the problem of low value-added utilization rate of conversion of non-aromatic hydrocarbon (C5-C9) and C9+ heavy aromatic hydrocarbon in the prior art, and provides a method and a system for producing dimethylbenzene.
In order to achieve the above object, a first aspect of the present invention provides a method for producing xylene, comprising: an alkylation reaction and a transalkylation reaction which are sequentially carried out; under alkylation reaction conditions, alkane is contacted with benzene and hydrogen to carry out alkylation reaction; contacting at least c9+ heavy aromatics from alkylation, toluene, and hydrogen under transalkylation reaction conditions to effect transalkylation; wherein the alkane is raffinate oil and/or raffinate oil after hydrogenation; wherein the weight ratio of benzene to alkane is 1-9:1; wherein the weight ratio of the C9+ heavy aromatic hydrocarbon to the toluene is 1-5:1.
Preferably, the bromine index of the alkane is less than or equal to 500mgBr/100g; further preferably, the alkane has a bromine index of 200mgBr/100g or less.
Preferably, in the alkylation reaction, the weight ratio of benzene to alkane is 4-9:1.
Preferably, in the transalkylation reaction, the weight ratio of the c9+ heavy aromatic hydrocarbon to toluene is 1-2:1.
in a second aspect, the invention provides a system for producing xylenes, the system comprising: the device comprises an alkane supply unit, a benzene supply unit, a hydrogen supply unit, a C9+ heavy aromatic hydrocarbon supply unit, an alkylation reactor and a transalkylation reactor, wherein the alkane supply unit, the benzene supply unit and the hydrogen supply unit are respectively communicated with the alkylation reactor, and the C9+ heavy aromatic hydrocarbon supply unit and the hydrogen supply unit are respectively communicated with the transalkylation reactor.
The system also optionally includes a hydrofinishing reactor disposed between the alkane supply unit and the alkylation reactor.
The inventor of the invention researches and discovers that by using cheap alkane, particularly reforming or steam cracking byproduct non-aromatic hydrocarbon and benzene as raw materials, catalytically producing toluene and xylene through alkane alkylation technology, then performing transalkylation reaction on C9+ heavy aromatic hydrocarbon with low added value and toluene to obtain xylene, recycling benzene in the alkylation reaction through simple separation, recycling toluene in the transalkylation reaction, and finally obtaining high-yield xylene with remarkable economic value.
Furthermore, the invention can convert alkane (C5-C9), in particular non-aromatic hydrocarbon and C9+ heavy aromatic hydrocarbon which are byproducts of catalytic reforming or steam cracking, into dimethylbenzene, greatly improves the added value thereof, has high dimethylbenzene yield, and can byproduct high-quality olefin pyrolysis materials of at least one of ethane, propane and the like; the method has the characteristics of simple process flow, high product rise value and the like, successfully solves the problem of the outlet of alkane (C5-C9) and C9+ heavy aromatic hydrocarbon, can fully utilize the methyl source in the alkane, and has remarkable direct economic benefit.
Drawings
Fig. 1 is a schematic diagram of a system provided by the present invention.
Description of the reference numerals
1-hydrofining reactor 2-alkylation reactor 3-stripping tower
4-benzene fractionating tower 5-toluene fractionating tower 6-xylene fractionating tower
7-transalkylation reactor 8-alkane feed unit 9-benzene feed unit
10-Hydrogen supply Unit 11-C9+ heavy aromatic supply Unit
Detailed Description
The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein.
In a first aspect, the invention provides a process for producing xylenes, the process comprising: an alkylation reaction and a transalkylation reaction which are sequentially carried out; under alkylation reaction conditions, alkane is contacted with benzene and hydrogen to carry out alkylation reaction; wherein at least c9+ heavy aromatics from the alkylation reaction, toluene and hydrogen are contacted under transalkylation reaction conditions to effect transalkylation reaction; the alkane is raffinate oil and/or raffinate oil after hydrogenation; wherein the weight ratio of benzene to alkane is 1-9:1; wherein the weight ratio of the C9+ heavy aromatic hydrocarbon to the toluene is 1-5:1.
By adopting the method, the cheap alkane and benzene are used as raw materials, toluene and xylene are produced by catalysis through an alkane alkylation technology, then the benzene and the xylene are obtained by alkyl transfer of the C9+ heavy aromatic hydrocarbon with low added value and the toluene, the benzene is recycled in the alkylation reaction through simple separation, the toluene is recycled in the alkyl transfer reaction, finally the high-yield xylene is obtained, and the yield of the xylene is obviously improved.
In the present invention, "at least part of the c9+ heavy aromatics from the alkylation reaction" is understood to mean that the c9+ heavy aromatics may all be derived from the alkylation reaction, and when the amount of alkylation reaction is insufficient to provide the c9+ heavy aromatics required for the transalkylation reaction, it is understood that the c9+ heavy aromatics source comprises two parts, and a part of the c9+ heavy aromatics derived from the alkylation reaction, i.e. "at least part of the c9+ heavy aromatics derived from the alkylation reaction" as described above; the other part is provided off-system, for example from a c9+ cut fraction from catalytic reforming and/or steam cracking.
In the present invention, toluene is understood to be derived from the alkylation reaction.
According to the present invention, it is preferable that the bromine index of the alkane is 500mgBr/100g or less, and it is further preferable that the bromine index of the alkane is 200mgBr/100g or less. Further research by the inventor finds that the alkane meeting the bromine index under the preferred scheme of the invention is favorable for alkylation reaction, and particularly has a larger influence on the activity of the catalyst, so that the alkane has better reaction performance.
In the present invention, the raffinate oil is a raffinate oil conventionally defined in the art, and will not be described herein. Preferably, the raffinate is a catalytically reformed and/or steam cracked raffinate.
In the present invention, it is noted that the term "non-aromatic" as used herein means that the component is substantially free of aromatic hydrocarbons, rather than being absolutely free of aromatic hydrocarbons. Aromatics in minor amounts (less than 1 wt%) may be referred to as non-aromatic components when the raffinate oil contains less than 1 wt%.
In the present invention, the raffinate oil is mainly composed of an alkane selected from at least one of normal alkane, isoparaffin and cycloalkane, and a small amount of unsaturated hydrocarbon such as at least one of olefin and aromatic hydrocarbon. Preferably, the raffinate oil comprises 95 to 99.99 wt.% C5-C9 alkanes and 0.01 to 5 wt.% C5-C9 unsaturated hydrocarbons.
Further, the "C5-C9 alkane" in the present invention means an alkane having a total number of carbon atoms of 5 to 9, and includes straight-chain alkane, branched alkane or cycloalkane, and specifically may be straight-chain alkane, branched alkane or cycloalkane having a total number of carbon atoms of 5, 6, 7, 8 and 9, and may be, for example, n-pentane, n-hexane, n-heptane, methylcyclohexane, ethylcyclopentane and the like. The "C5-C9 unsaturated hydrocarbon" means an unsaturated hydrocarbon having a total of 5 to 9 carbon atoms, and includes olefins or aromatic hydrocarbons, specifically, olefins or aromatic hydrocarbons having a total of 5, 6, 7, 8 and 9 carbon atoms, for example, hexene, heptene, methyl hexene, benzene and the like.
In the present invention, it is understood that when the composition of the raffinate oil does not meet the required bromine index, the raffinate oil may be hydrogenated to meet the required bromine index after being hydrogenated and saturated; when the unsaturated hydrocarbon content in the composition of the raffinate oil is low and meets the required bromine index, the raffinate oil can be directly used as the alkane for subsequent alkylation without hydrogenation.
According to the invention, preferably, the alkane is hydrogenated raffinate oil, and the hydrogenation condition is that the raffinate oil satisfies the bromine index after hydrogenation. Preferably, the hydrogenation is carried out in the presence of hydrogen, the hydrogen (notably, hydrogen in the hydrogenation process) and alkane having a hydrogen to oil volume ratio of from 100 to 500:1, more preferably from 150 to 200:1.
In the present invention, preferably, the hydrogenation is carried out in the presence of a hydrogenation catalyst.
In a preferred embodiment, the hydrogenation conditions comprise: the mass airspeed of the alkane is 1-8h -1 More preferably 1 to 5 hours -1 The temperature is 150-200deg.C, more preferably 165-180deg.C, and the pressure is 1-5MPa, more preferably 3-5MPa.
In the present invention, the hydrogenation catalysts conventionally defined in the art are suitable for use in the present invention, provided that the desired bromine index is achieved after the alkane is hydrosaturated. Preferably, the hydrogenation catalyst comprises a carrier and a metal active component supported on the carrier, wherein the metal active component is selected from at least one of group VIII elements, group VIB elements, group IIB elements and group IIA elements.
In a preferred embodiment, the metal active component is present in an amount of from 10 to 20% by weight, based on the total amount of catalyst, and the support is present in an amount of from 80 to 90% by weight, based on the element.
In the present invention, the selection range of the carrier type is wide. Preferably, the support is selected from at least one of alumina, titania, zirconia and silica; more preferably alumina.
In the present invention, the selection range of the kind of the metal active component is wide. Preferably, the metal active component is selected from at least one of a group VIII metal element, a group VIB metal element, a group IIB metal element, and a group IIA metal element. More preferably, the metal active component is selected from at least one of Ni, mo, W, zn and Mg.
In the present invention, the hydrogenation catalyst may be commercially available, for example, RN-1 catalyst, from chinese petrochemical catalyst company, or may be prepared by an existing method, and will not be described herein.
In the present invention, the alkylation reaction is capable of converting more of the alkanes (preferably C5-C9 alkanes) in the alkane to alkylbenzenes (principally toluene and xylenes). Preferably, the weight ratio of benzene to alkane is 4-9:1.
In the present invention, the conditions for the alkylation reaction are selected in a wide range. Preferably, the alkylation reaction conditions include: the temperature is 450-550 ℃, the pressure is 1-7MPa, and the weight space velocity of benzene and alkane is 1-10h -1 The volume ratio of hydrogen to oil is 500-2000:1; further preferably, the alkylation reaction conditions include: the temperature is 480-520 ℃, the pressure is 3-5MPa, and the weight space velocity of benzene and alkane is 4-8h -1 The volume ratio of hydrogen to oil is 1000-2000:1. In the invention, the unsaturated hydrocarbon existing in the alkylation reaction can be better hydrogenated by adopting the proper amount of hydrogen so as to avoid the adverse effects caused by the possible polymerization or polycondensation of the unsaturated hydrocarbon (including the unsaturated hydrocarbon in alkane, the unsaturated hydrocarbon generated by side reactions such as hydrogen transfer and the like possibly occurring in the alkylation reaction) in the alkylation reaction to form carbon deposit.
In the present invention, preferably, the alkylation reaction is carried out in the presence of an alkylation catalyst comprising a molecular sieve, a binder, and optionally an active metal component, and further preferably, the alkylation catalyst comprises a molecular sieve and a binder. The alkylation catalyst has the advantages of high benzene single pass conversion rate and high toluene and xylene yields.
In the invention, the selection range of the types of the molecular sieve is wider. Preferably, the molecular sieve is selected from at least one of ZSM-5 molecular sieve, MCM-22 molecular sieve, ZSM-12 molecular sieve, beta molecular sieve and MOR zeolite molecular sieve, more preferably ZSM-5 molecular sieve.
In a preferred embodiment, the molecular sieve has a molar ratio of silicon to aluminum of from 20 to 70, preferably from 20 to 50. The adoption of the preferable scheme has the advantages of high raw material conversion rate and good selectivity of target products.
In the present invention, the molecular sieve may be an acid-modified molecular sieve or an acid-unmodified molecular sieve, and preferably the molecular sieve is an acid-modified ammonium molecular sieve, and the acid modification method is a method existing in the art. Preferably, the acid is at least one selected from citric acid, phosphoric acid, hydrochloric acid and oxalic acid, and can be selected by one skilled in the art according to the needs, and will not be described herein.
In the present invention, the kind of the binder is not particularly limited, and binders conventionally defined in the art are suitable for the present invention. Preferably, the binder is alumina and/or silica.
In a preferred embodiment, the metal component is selected from at least one of Mg, re, cu, mo, la, K, na and Pt, more preferably at least one of Re, pt and Mo.
In the present invention, the amount of each substance in the alkylation catalyst is not particularly limited as long as the alkylation reaction is facilitated. Preferably, the metal component is contained in an amount of 0 to 0.5 parts by weight in terms of elements and the binder is contained in an amount of 10 to 40 parts by weight based on 100 parts by weight of the alkylation catalyst.
In the present invention, the preparation method of the alkylation catalyst has a wide selection range, so long as the above-mentioned alkylation catalyst can be obtained. In a particularly preferred embodiment, the alkylation catalyst is prepared by the following method: the molecular sieve is mixed with a binder to form, dried and calcined, and then optionally impregnated with a metal component. In the present invention, the molding method is not limited, and may be, for example, an existing standard molding method, specifically, a method of mixing molecular sieve powder with a binder, adding the mixture to a bar extruder equipped with a die, and extruding the powder as a bar extrudate. In the present invention, the impregnation method is not particularly limited as long as the metal component is impregnated on the baked product, and for example, the impregnation method may be performed according to any impregnation method existing in the art, for example, at least one of co-impregnation, stepwise impregnation and isovolumetric impregnation, and the present invention is not limited thereto. In the present invention, the timing of introducing the metal component is also not particularly limited, and may be performed, for example, after the molecular sieve is prepared. Specifically, for example, the molding and baking may be performed before the molding and baking, or may be performed after the molding and baking; the metal component can also be introduced in the process of preparing the molecular sieve, specifically, for example, the metal component is supported on alumina in advance and then mixed with the molecular sieve for molding, and the metal component can be selected by a person skilled in the art according to actual requirements.
According to one embodiment of the invention, the alkylation catalyst is obtained by the following method: mixing molecular sieve with binder, adding into extrusion machine with mould, extruding powder into bar-shaped extrudate, drying, roasting, optionally introducing metal component by impregnation method, drying and roasting to obtain alkylation catalyst.
In the present invention, the types and amounts of each substance in the alkylation catalyst are described above, and will not be described in detail herein.
In the present invention, the method of preparing the transalkylation catalyst comprises introducing an extrusion aid and/or a peptizing agent during the molding process.
In the present invention, the types and amounts of the extrusion aid and the peptizing agent are not particularly limited, and those skilled in the art can select the types and amounts of the extrusion aid and the peptizing agent in a reasonable range according to the specific conditions of extrusion molding. Preferably, the extrusion aid is selected from at least one of sesbania powder, dextrin and methylcellulose. Preferably, the peptizing agent is selected from at least one of nitric acid, acetic acid, and citric acid.
In a preferred embodiment, the extrusion aid is used in an amount of 2.5 to 10 parts by weight and the peptizing agent is used in an amount of 2.5 to 5 parts by weight based on 100 parts by weight of the molecular sieve.
In the present invention, the drying conditions used in the molding and impregnating processes may be selected from a wide range of conditions, and may be conventional drying conditions in the art. Preferably, the drying conditions of the shaping and impregnation each independently comprise a drying temperature of 100-120 ℃ for a period of 12-24 hours.
In the invention, the conditions for the calcination in the molding and impregnation process are selected in a wide range, and can be conventional calcination conditions in the field. Preferably, the firing conditions for the molding and the impregnating each independently include a firing temperature of 500 to 600 ℃, a firing time of 2 to 12 hours, and further preferably, a firing temperature of 500 to 550 ℃, and a firing time of 2 to 5 hours.
In the present invention, the amount of each substance used in the transalkylation reaction is not particularly limited. Preferably, in the transalkylation reaction, the weight ratio of the c9+ heavy aromatic hydrocarbon to toluene is 1-2:1. the xylene yield can be increased by limiting the amount of toluene and c9+ heavy aromatics used.
In the present invention, the conditions for the transalkylation reaction are selected in a wide range. Preferably, the transalkylation reaction conditions include: the temperature is 250-450 ℃, the pressure is 1-7MPa, and the weight space velocity of toluene and C9+ heavy aromatics is 1-6h -1 The volume ratio of hydrogen to oil is 500-2000:1; further preferably, the temperature is 300-450 ℃, the pressure is 2-4MPa, and the weight space velocity of toluene and C9+ heavy aromatics is 1-4h -1 The volume ratio of hydrogen to oil is 1000-2000:1. By adopting the preferred embodiment, the catalyst has the advantages of stable operation and high xylene yield.
In the present invention, preferably, the transalkylation reaction is carried out in the presence of a transalkylation catalyst comprising a transalkylation molecular sieve, a binder, and optionally an active component, and further preferably, the transalkylation catalyst comprises a transalkylation molecular sieve, a binder, and an active component.
In the present invention, the range of selection of the type of the transalkylation molecular sieve is wide, for example, the transalkylation molecular sieve is at least one selected from the group consisting of ZSM-5 molecular sieve, MCM-22 molecular sieve, ZSM-12 molecular sieve, beta molecular sieve and MOR zeolite catalyst, and more preferably is MOR zeolite molecular sieve.
In a preferred embodiment, the transalkylation molecular sieve has a molar ratio of silica to alumina of 20 to 70, preferably 20 to 50. Under the preferable scheme, the method is more beneficial to improving the yield of the dimethylbenzene.
In the present invention, the transalkylation molecular sieve is an ammonium molecular sieve modified by acid, and the acid modification method and the acid type in the present invention are described above, and are not described herein.
In a preferred embodiment, the binder is alumina and/or silica.
In a preferred embodiment, the active component is selected from at least one of Mo, re, bi, sn and Pt, more preferably at least one of Mo, bi and Pt. By adopting the preferred embodiment, the conversion rate of C9+ heavy aromatic hydrocarbon is high, and the xylene yield is high.
In the present invention, the content of each substance in the transalkylation catalyst is not particularly limited. Preferably, the active component is contained in an amount of 0.01 to 1 part by weight in terms of element and the binder is contained in an amount of 10 to 45 parts by weight, based on 100 parts by weight of the transalkylation catalyst, and further preferably, the active component is contained in an amount of 0.01 to 0.8 part by weight in terms of element and the binder is contained in an amount of 20 to 45 parts by weight. In the present invention, the preparation method of the transalkylation catalyst has a wide selection range, so long as the transalkylation reaction can be facilitated, for example, the transalkylation catalyst can be prepared by using the same preparation method as that of the alkylation catalyst, and the specific preparation method is described in the foregoing, and is not described herein.
To further allow for better directed conversion of the alkylation reaction to alkylbenzenes (primarily toluene and xylenes), as shown in FIG. 1, in one embodiment, the process for producing xylenes comprises: (1) Optionally hydrogenating the raffinate oil under hydrogenation conditions to obtain alkanes (hydrogenated raffinate oil); (2) Under the alkylation reaction condition, the alkane is contacted with benzene and hydrogen to carry out alkylation reaction, the weight ratio of the benzene to the alkane is 1-9:1, the alkylation reaction is carried out in the presence of an alkylation catalyst, the temperature is 450-550 ℃, the pressure is 1-7MPa, and the weight space velocity of the benzene and the alkane is 1-10h -1 The volume ratio of hydrogen to oil is 500-2000:1; (3) Contacting at least C9+ heavy aromatics from alkylation, toluene, and hydrogen under transalkylation reaction conditions, the weight ratio of C9+ heavy aromatics to toluene being 1:5-1, the transalkylation reaction in the presence of a transalkylation catalystThe temperature is 250-450 ℃, the pressure is 1-7MPa, and the weight space velocity of toluene and C9+ heavy aromatics is 1-6h -1 The volume ratio of hydrogen to oil is 500-2000:1. Under the preferred scheme, the conversion rate of benzene and C9+ heavy aromatics and the yield of xylene are optimal, the conversion rate of benzene reaches 38.85%, the conversion rate of C9+ heavy aromatics reaches 58.23%, and the yield of xylene reaches more than 32.17%.
According to a preferred embodiment of the present invention, as shown in fig. 1, the method further comprises: the aromatic hydrocarbon-containing product obtained by the alkylation reaction and the transalkylation reaction is optionally cooled and then subjected to gas-liquid separation to obtain a gas-phase material (for example, light hydrocarbon such as ethylene, propane and the like shown in fig. 1) and a liquid-phase material. In the present invention, the cooling is preferably to 25 ℃ or lower.
According to a preferred embodiment of the present invention, as shown in fig. 1, the method further comprises: fractionating the liquid phase material to obtain benzene, toluene, xylene and C9+ heavy aromatic hydrocarbon.
The conditions of the fractionation are not limited in the present invention as long as the above-mentioned several materials are obtained. Preferably, the process of fractionation comprises: first fractionating to obtain benzene with a distillation range of 65-85 ℃; then carrying out second fractionation to obtain toluene, wherein the distillation range of the toluene is 85-105 ℃; and then carrying out third fractionation to obtain dimethylbenzene and C9+ heavy aromatic hydrocarbon, wherein the distillation range of the dimethylbenzene is 105-145 ℃.
According to the invention, preferably, the method further comprises: recycling the benzene obtained by fractionation into the alkylation reaction, and recycling the toluene obtained by fractionation and C9+ heavy aromatic hydrocarbon into the transalkylation reaction. The advantage of adopting the preferred embodiment is that the methyl of alkane in the raffinate oil can be fully utilized, and the maximum utilization of methyl is realized.
In a second aspect, the invention provides a system for producing xylenes, as shown in FIG. 1, the system comprising: an alkane supply unit 8, a benzene supply unit 9, a hydrogen supply unit 10, a C9+ heavy aromatic hydrocarbon supply unit 11, an alkylation reactor 2 and a transalkylation reactor 7, wherein the alkane supply unit 10, the benzene supply unit 9 and the hydrogen supply unit 10 are respectively communicated with the alkylation reactor 2, the C9+ heavy aromatic hydrocarbon supply unit 11 and the hydrogen supply unit 10 are respectively communicated with the transalkylation reactor 7, and the alkylation reactor 2 and the transalkylation reactor 7 are respectively communicated.
The system also optionally comprises a hydrofinishing reactor 1, said hydrofinishing reactor 1 being arranged between said alkane supply unit 8 and said alkylation reactor 2.
In the present invention, it is noted that the alkane supply unit 8 and the alkylation reactor 2 may be in direct communication; a hydrofining reactor 1 may also be provided, i.e. the alkane feed unit 8 and the alkylation reactor 2 are each in communication with the hydrofining reactor 1.
According to the system provided by the invention, the system preferably further comprises a stripping tower 3, wherein the stripping tower 3 is used for gas-liquid separation to obtain gas-phase materials and liquid-phase materials.
According to the system provided by the invention, preferably, the system further comprises a benzene fractionating tower 4, the benzene fractionating tower 4 carries out first fractionation on the liquid phase material separated by the stripping tower 3 to obtain benzene, an inlet of the benzene fractionating tower 4 is communicated with a liquid outlet at the bottom of the stripping tower 3, and an overhead benzene material outlet of the benzene fractionating tower 4 is communicated with the benzene supply unit 9 for recycling unreacted benzene in alkylation reaction.
According to the system provided by the invention, preferably, the system further comprises a toluene fractionating tower 5, wherein the inlet of the toluene fractionating tower 5 is communicated with the bottom outlet of the benzene fractionating tower 4 and is used for carrying out second fractionation on liquid phase materials obtained from the bottom outlet of the benzene fractionating tower 4 to obtain toluene, and the top toluene material outlet of the toluene fractionating tower 5 is communicated with the transalkylation reactor 7 and is used for providing toluene for transalkylation reaction.
According to the system provided by the invention, preferably, the system further comprises a xylene fractionation tower 6, wherein the inlet of the xylene fractionation tower 6 is communicated with the bottom outlet of the toluene fractionation tower 5; and the liquid phase material obtained from the bottom outlet of the toluene fractionating tower 5 is subjected to third fractionation to obtain dimethylbenzene and C9+ heavy aromatic hydrocarbon.
According to the system provided by the invention, the system further comprises a tower bottom C9+ heavy aromatic hydrocarbon material outlet separated by the xylene fractionating tower 6 is communicated with the transalkylation reactor 7.
The system provided by the invention can realize the method of the first aspect, combines alkylation reaction and transalkylation reaction, and particularly, by taking alkane as a methyl source reagent to carry out the alkylation reaction in the system, benzene can be effectively converted into toluene and dimethylbenzene, and the introduction of reaction hydrogen is beneficial to reducing the carbon deposition rate of a catalyst, improving the stability of the catalyst and further carrying out the transalkylation reaction, thereby being more beneficial to improving the yield of dimethylbenzene.
The present invention will be described in detail by examples.
Example 1
(1) SiO is made of 2 /Al 2 O 3 Ammonium ZSM-5 zeolite (from China petrochemical catalyst Co., ltd.) in a molar ratio of 25, 47.05g and 14.3g gamma-Al 2 O 3 Uniformly mixing, adding a certain amount of sesbania powder and dilute nitric acid, extruding, forming, drying at 120 ℃ for 12 hours, and then placing in a muffle furnace for roasting at 550 ℃ for 4 hours to obtain the alkylation catalyst W-1.
(2) SiO is made of 2 /Al 2 O 3 Ammonium Beta zeolite (available from China petrochemical catalyst Co., ltd.) having a molar ratio of 50, 47.05g to 35g of gamma-Al 2 O 3 Uniformly mixing, adding a certain amount of sesbania powder and dilute nitric acid, extruding, molding, drying at 120 ℃ for 12 hours, placing in a muffle furnace for roasting at 550 ℃ for 4 hours to obtain a transalkylation catalyst precursor, immersing a certain amount of chloroplatinic acid solution, drying at 120 ℃ for 12 hours, placing in the muffle furnace for roasting at 550 ℃ for 4 hours, and obtaining the transalkylation catalyst V-1 (0.5 wt% Pt/catalyst V-1).
(3) Using the system shown in FIG. 1, 3g of alkylation catalyst W-1 was placed in alkylation reactor 2 and 5g of transalkylation catalyst V-1 was placed in transalkylation reactor 7. The top of the alkylation reactor 2 was fed with hydrogen and a material containing benzene and alkane (for steam cracking, the composition is shown in Table 1, the bromine index of the alkane is 125mgBr/100 g) to contact with the alkylation catalyst inside the alkylation reactor 2, and the top of the transalkylation reactor 7 was fed with hydrogen and a material containing toluene and C9+ heavy aromatics, the composition of which is shown in Table 2, to contact with the transalkylation catalyst inside the transalkylation reactor 7.
Wherein, the alkylation reaction conditions are as follows: weight space velocity 7h -1 The temperature is 500 ℃, the pressure is 3MPa, the hydrogen-oil volume ratio is 1000, and the reaction raw material benzene: alkane = 4:1 (weight ratio). The transalkylation reaction conditions were: weight space velocity 2h -1 The temperature is 370 ℃, the pressure is 2.7MPa, the hydrogen-oil volume ratio is 1000, and the reaction raw material toluene: c9+ heavy aromatics=1:1 (weight ratio).
Specifically, in example 1, a system shown in fig. 1 is adopted, hydrogen is provided by a hydrogen supply unit 10, alkane and benzene are provided by an alkane supply unit 8 and a benzene supply unit 9 respectively, and then the mixture enters an alkylation reactor 2 to carry out alkylation reaction (alkylation reaction conditions are as described above) to obtain an alkylation reaction product, the alkylation reaction product is cooled and treated, then enters a stripping tower 3 to carry out gas-liquid separation, light hydrocarbons are separated (as shown in fig. 1), the bottom material of the stripping tower 3 enters a benzene fractionating tower 4 to carry out first fractionation (the distillation range is 65-85 ℃), benzene is fractionated, a part of benzene is returned to the alkylation reactor 2 to carry out alkylation reaction, and the bottom material of the benzene fractionating tower 4 enters a toluene fractionating tower 5 (the distillation range is 85-105 ℃), and toluene is fractionated. The bottom material of the toluene fractionating tower 5 enters a xylene fractionating tower 6 (the distillation range is 105-145 ℃) to fractionate the xylenes and C9+ heavy aromatics. Toluene enters the transalkylation reactor 7 to carry out transalkylation reaction (the transalkylation reaction conditions are as described above) with the C9+ heavy aromatic hydrocarbon supplied by the C9+ heavy aromatic hydrocarbon supply unit 11 and the C9+ heavy aromatic hydrocarbon distilled off by the xylene fractionation column 6, and hydrogen can be supplied through the hydrogen supply unit 10, and the transfer product after the transalkylation reaction can be returned to the alkylation reactor 2 for reuse.
The product content was tested by gas chromatography and benzene conversion, c9+ heavy aromatics conversion and xylene yield were calculated as shown in table 3.
The calculation formula of benzene conversion is = (raw material benzene mass-residual benzene mass)/raw material benzene mass x 100%.
The formula of conversion of c9+ heavy aromatics is = (mass of c9+ heavy aromatics of raw material-mass of remaining c9+ heavy aromatics)/mass of c9+ heavy aromatics of raw material ×100%.
The calculation formula of the xylene yield is =the mass of xylenes in the product/(total mass of raw benzene and c9+ heavy aromatics) ×100%, the xylenes being a mixture of ortho-, para-and meta-xylene.
Example 2
(1) SiO is made of 2 /Al 2 O 3 Ammonium ZSM-5 zeolite (from China petrochemical catalyst Co., ltd.) in a molar ratio of 25, 47.05g and 14.3g gamma-Al 2 O 3 Uniformly mixing, adding a certain amount of sesbania powder and dilute nitric acid, extruding, molding, drying at 120 ℃ for 12 hours, placing in a muffle furnace for roasting at 550 ℃ for 4 hours to obtain an alkylation catalyst precursor, immersing a certain amount of chloroplatinic acid solution, drying at 120 ℃ for 12 hours, placing in the muffle furnace for roasting at 550 ℃ for 4 hours, and obtaining the alkylation catalyst W-2 (0.5 wt% Pt/catalyst W-2).
(2) The same transalkylation catalyst V-1 (0.5 wt.% Pt/Beta) as in example 1 was used.
(3) Using the system shown in FIG. 1, 3g of alkylation catalyst W-2 was placed in alkylation reactor 2 and 5g of transalkylation catalyst V-1 was placed in transalkylation reactor 7. The benzene conversion, c9+ heavy aromatics conversion, and xylene yield were calculated by gas chromatography testing the product content using the same alkylation reaction feedstock and conditions and transalkylation reaction feedstock and conditions as in example 1, as shown in table 3.
Example 3
(1) According to the method of example 1, except that SiO was used 2 /Al 2 O 3 Ammonium ZSM-5 zeolite (available from China petrochemical catalyst Co., ltd.) having a molar ratio of 38, to give alkylation catalyst W-3.
(2) The same transalkylation catalyst V-1 as in example 1 was used.
(3) Using the system shown in FIG. 1, 3g of alkylation catalyst W-3 was placed in alkylation reactor 2 and 5g of transalkylation catalyst V-1 was placed in transalkylation reactor 7. The benzene conversion, c9+ heavy aromatics conversion, and xylene yield were calculated by gas chromatography testing the product content using the same alkylation reaction feedstock and conditions and transalkylation reaction feedstock and conditions as in example 1, as shown in table 3.
Example 4
(1) The same alkylation catalyst W-3 as in example 3 was used.
(2) SiO is made of 2 /Al 2 O 3 Ammonium MOR zeolite (available from China petrochemical catalyst Co., ltd.) having a molar ratio of 30, 47.05g and 35g gamma-Al 2 O 3 Uniformly mixing, adding a certain amount of sesbania powder and dilute nitric acid, extruding, molding, drying at 120 ℃ for 12 hours, placing in a muffle furnace for roasting at 550 ℃ for 4 hours to obtain a transalkylation catalyst precursor, immersing a certain amount of chloroplatinic acid solution, drying at 120 ℃ for 12 hours, and placing in the muffle furnace for roasting at 550 ℃ for 4 hours to obtain the transalkylation catalyst V-2 (0.5 wt% Pt/catalyst V-2).
(3) Using the system shown in FIG. 1, 3g of alkylation catalyst W-3 was placed in alkylation reactor 2 and 5g of catalyst V-2 was placed in transalkylation reactor 7. The benzene conversion, c9+ heavy aromatics conversion, and xylene yield were calculated by gas chromatography testing the product content using the same alkylation reaction feedstock and conditions and transalkylation reaction feedstock and conditions as in example 1, as shown in table 3.
Example 5
(1) SiO is made of 2 /Al 2 O 3 Ammonium ZSM-5 zeolite (from China petrochemical catalyst Co., ltd.) having a molar ratio of 38, 47.05g and 14.3g gamma-Al 2 O 3 Uniformly mixing, adding a certain amount of sesbania powder and dilute nitric acid, extruding, molding, drying at 120 ℃ for 12 hours, placing in a muffle furnace for roasting at 550 ℃ for 4 hours to obtain an alkylation catalyst precursor, immersing a certain amount of ammonium molybdate solution, drying at 120 ℃ for 12 hours, placing in the muffle furnace for roasting at 550 ℃ for 4 hours to obtain an alkylation catalyst W-4 (0.5 wt% Mo/catalyst W-4).
(2) The same transalkylation catalyst V-2 as in example 4 was used.
(3) Using the system shown in FIG. 1, 3g of alkylation catalyst W-4 was placed in alkylation reactor 2 and 5g of transalkylation catalyst V-2 was placed in transalkylation reactor 7. The benzene conversion, c9+ heavy aromatics conversion, and xylene yield were calculated by gas chromatography testing the product content using the same alkylation reaction feedstock and conditions and transalkylation reaction feedstock and conditions as in example 1, as shown in table 3.
Example 6
The process of example 4 is followed except that the alkane is hydrogenated raffinate. Using the system as described in FIG. 1, alkane (bromine index of catalytic reforming was 1200mgBr/100 g) was contacted with hydrogenation catalyst (i.e. RN-1 catalyst, 13.05 wt% Mo-2.75 wt% Ni/RN-1 catalyst available from China petrochemical catalyst Co., ltd.) in hydrofining reactor 1, and unsaturated hydrocarbons were removed by hydrogenation to obtain hydrogenated raffinate oil composition having bromine index of 165mgBr/100g as shown in Table 1. Wherein, the hydrogenation conditions are as follows: the volume ratio of hydrogen oil is 150:1, and the mass airspeed of raffinate oil is 5h -1 The benzene conversion, c9+ heavy aromatics conversion and xylene yield were calculated by gas chromatography testing the product content under the same conditions as in example 4 at 165 ℃ and 3MPa, as shown in table 3.
Example 7
According to the method of example 4, except that the active components of the transalkylation catalyst were Mo and Bi, transalkylation catalyst V-3 (0.3 wt.% Mo/0.5 wt.% Bi-MOR) was produced under the same conditions as in example 4, and the product content was tested by gas chromatography to calculate benzene conversion, C9+ heavy aromatics conversion and xylene yield as shown in Table 3.
Example 8
The method of example 4 is followed, except that the benzene and alkane are present in a weight ratio of 1:1, wherein the weight ratio of the C9+ heavy aromatic hydrocarbon to the toluene is 1: the transalkylation catalyst V-3 of example 7 was used, and the benzene conversion, C9+ heavy aromatics conversion and xylene yield were calculated by gas chromatography testing the product content under the same conditions as in example 4, as shown in Table 3.
Example 9
The method of example 4 was followed, except that the benzene and alkane weight ratio was 9:1, wherein the weight ratio of the C9+ heavy aromatic hydrocarbon to toluene is 5: the transalkylation catalyst V-3 of example 7 was used, and the benzene conversion, C9+ heavy aromatics conversion and xylene yield were calculated by gas chromatography testing the product content under the same conditions as in example 4, as shown in Table 3.
Comparative example 1
The method of example 4 was followed, except that the benzene and alkane weight ratio was 20:1, wherein the weight ratio of the C9+ heavy aromatic hydrocarbon to toluene is 20: the transalkylation catalyst V-3 of example 7 was used, and the benzene conversion, C9+ heavy aromatics conversion and xylene yield were calculated by gas chromatography testing the product content under the same conditions as in example 4, as shown in Table 3.
TABLE 1 content of components in hydrocarbons (wt.%)
Note that: in table 1 "-" indicates no inclusion.
TABLE 2
TABLE 3 Table 3
As can be seen from the above Table 3, the method of the present invention can combine alkylation reaction and transalkylation reaction with non-aromatic hydrocarbon (C5-C9), especially non-aromatic hydrocarbon and C9+ heavy aromatic hydrocarbon as byproducts of catalytic reforming or steam cracking, as raw materials, and has the characteristics of high conversion rate of non-aromatic hydrocarbon and high yield of xylene.
The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, a number of simple variants of the technical solution of the invention are possible, including combinations of the individual technical features in any other suitable way, which simple variants and combinations should likewise be regarded as being disclosed by the invention, all falling within the scope of protection of the invention.
Claims (10)
1. A method of producing xylenes, the method comprising: an alkylation reaction and a transalkylation reaction which are sequentially carried out; under alkylation reaction conditions, alkane is contacted with benzene and hydrogen to carry out alkylation reaction; contacting at least c9+ heavy aromatics from alkylation, toluene, and hydrogen under transalkylation reaction conditions to effect transalkylation; wherein the alkane is raffinate oil and/or raffinate oil after hydrogenation; wherein the weight ratio of benzene to alkane is 1-9:1; wherein the weight ratio of the C9+ heavy aromatic hydrocarbon to the toluene is 1-5:1.
2. The process according to claim 1, wherein the alkane has a bromine index of 500mgBr/100g or less;
preferably, the bromine index of the alkane is less than or equal to 200mgBr/100g;
preferably, the raffinate is a catalytically reformed and/or steam cracked raffinate;
preferably, the raffinate oil comprises 95 to 99.99 wt.% C5-C9 alkanes and 0.01 to 5 wt.% C5-C9 unsaturated hydrocarbons;
preferably, in the alkylation reaction, the weight ratio of benzene to alkane is 4-9:1.
3. The process of claim 1 or 2, wherein the alkylation reaction conditions comprise: the temperature is 450-550 ℃, the pressure is 1-7MPa, and the weight space velocity of benzene and alkane is 1-10h -1 The volume ratio of hydrogen to oil is 500-2000:1;
preferably, the alkylation reaction conditions include: the temperature is 480-520 ℃, the pressure is 3-5MPa, and the weight space velocity of benzene and alkane is 4-8h -1 The volume ratio of hydrogen to oil is 1000-2000:1;
preferably, the alkylation reaction is carried out in the presence of an alkylation catalyst comprising a molecular sieve, a binder, and optionally a metal component, further preferably, the alkylation catalyst comprises a molecular sieve and a binder;
preferably, the molecular sieve is selected from at least one of a ZSM-5 molecular sieve, an MCM-22 molecular sieve, a ZSM-12 molecular sieve, a Beta molecular sieve, and a MOR zeolite molecular sieve, more preferably a ZSM-5 molecular sieve;
preferably, the molecular sieve has a molar ratio of silicon to aluminum of 20 to 70, more preferably 20 to 50;
preferably, the binder is alumina and/or silica;
preferably, the metal component is selected from at least one of Mg, re, cu, mo, la, K and Pt elements;
preferably, the metal component is contained in an amount of 0 to 0.5 parts by weight in terms of elements and the binder is contained in an amount of 10 to 40 parts by weight based on 100 parts by weight of the alkylation catalyst.
4. A process according to any one of claims 1 to 3, wherein the weight ratio of c9+ heavy aromatics to toluene in the transalkylation reaction is 1-2:1.
5. The method of any of claims 1-4, wherein the transalkylation reaction conditions include: the temperature is 250-450 ℃, the pressure is 1-7MPa, and the weight space velocity of toluene and C9+ heavy aromatics is 1-6h -1 The volume ratio of hydrogen to oil is 500-2000:1; preferably, the temperature is 300-450 ℃, the pressure is 2-4MPa, and the weight space velocity of toluene and C9+ heavy aromatics is 1-4h -1 The volume ratio of hydrogen to oil is 1000-2000:1;
preferably, the transalkylation reaction is carried out in the presence of a transalkylation catalyst comprising a transalkylation molecular sieve, a binder, and optionally an active component, further preferably, the transalkylation catalyst comprises a transalkylation molecular sieve, a binder, and an active component;
preferably, the transalkylation molecular sieve is selected from at least one of a ZSM-5 molecular sieve, a MCM-22 molecular sieve, a ZSM-12 molecular sieve, a Beta molecular sieve, and a MOR zeolite molecular sieve, more preferably a MOR zeolite molecular sieve;
preferably, the transalkylation molecular sieve has a molar ratio of silicon to aluminum of 20 to 70, more preferably 20 to 50;
preferably, the binder is alumina and/or silica;
preferably, the active component is selected from at least one of Mo, re, bi, sn and Pt elements;
preferably, the active component is contained in an amount of 0.01 to 1 part by weight in terms of element and the binder is contained in an amount of 10 to 45 parts by weight, based on 100 parts by weight of the transalkylation catalyst, and further preferably, the active component is contained in an amount of 0.01 to 0.8 part by weight in terms of element and the binder is contained in an amount of 20 to 45 parts by weight.
6. The method according to any one of claims 1-5, wherein the method further comprises: optionally cooling the aromatic hydrocarbon-containing product obtained by the alkylation reaction and the transalkylation reaction, and then carrying out gas-liquid separation to obtain a gas-phase material and a liquid-phase material.
7. The method of claim 6, wherein the method further comprises: fractionating the liquid phase material to obtain benzene, toluene, xylene and C9+ heavy aromatic hydrocarbon;
preferably, the process of fractionation comprises: first fractionating to obtain benzene with a distillation range of 65-85 ℃; then carrying out second fractionation to obtain toluene, wherein the distillation range of the toluene is 85-105 ℃; and then carrying out third fractionation to obtain dimethylbenzene and C9+ heavy aromatic hydrocarbon, wherein the distillation range of the dimethylbenzene is 105-145 ℃.
8. The method of claim 7, wherein the method further comprises: recycling the benzene obtained by fractionation into the alkylation reaction, and recycling the toluene obtained by fractionation and C9+ heavy aromatic hydrocarbon into the transalkylation reaction.
9. A system for producing xylenes, the system comprising: an alkane feed unit, a benzene feed unit, a hydrogen feed unit, a c9+ heavy aromatic hydrocarbon feed unit, an alkylation reactor and a transalkylation reactor, wherein the alkane feed unit, the benzene feed unit and the hydrogen feed unit are respectively in communication with the alkylation reactor, the c9+ heavy aromatic hydrocarbon feed unit and the hydrogen feed unit are respectively in communication with the transalkylation reactor, and the alkylation reactor and the transalkylation reactor are in communication;
the system also optionally includes a hydrofinishing reactor disposed between the alkane supply unit and the alkylation reactor.
10. The system of claim 9, further comprising a stripper for gas-liquid separation to obtain a gas phase material and a liquid phase material;
preferably, the system further comprises a benzene fractionating tower, wherein the inlet of the benzene fractionating tower is communicated with the bottom liquid phase material outlet of the stripping tower, and the top benzene material outlet of the benzene fractionating tower is communicated with the benzene supply unit and is used for recycling unreacted benzene as alkylation reaction raw material;
more preferably, the system further comprises a toluene fractionation column having an inlet in communication with a bottom outlet of the benzene fractionation column, and an overhead toluene feed outlet in communication with the transalkylation reactor for providing transalkylation-reacted toluene;
further preferably, the system further comprises a xylene fractionation column, the inlet of which is in communication with the bottom outlet of the toluene fractionation column.
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| CN202210603355.4A CN117185895A (en) | 2022-05-30 | 2022-05-30 | Method and system for producing xylene |
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| CN202210603355.4A CN117185895A (en) | 2022-05-30 | 2022-05-30 | Method and system for producing xylene |
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