CN114505094A - Modification method of ZSM-5 molecular sieve and ZSM-5 molecular sieve catalyst - Google Patents
Modification method of ZSM-5 molecular sieve and ZSM-5 molecular sieve catalyst Download PDFInfo
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- 239000002808 molecular sieve Substances 0.000 title claims abstract description 183
- URGAHOPLAPQHLN-UHFFFAOYSA-N sodium aluminosilicate Chemical compound [Na+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O URGAHOPLAPQHLN-UHFFFAOYSA-N 0.000 title claims abstract description 181
- 239000003054 catalyst Substances 0.000 title claims abstract description 44
- 238000002715 modification method Methods 0.000 title claims abstract description 26
- 239000002253 acid Substances 0.000 claims abstract description 91
- 238000006243 chemical reaction Methods 0.000 claims abstract description 51
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 38
- 239000007788 liquid Substances 0.000 claims abstract description 34
- 238000005406 washing Methods 0.000 claims abstract description 32
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 30
- 239000008367 deionised water Substances 0.000 claims abstract description 30
- 229910021641 deionized water Inorganic materials 0.000 claims abstract description 30
- 238000010438 heat treatment Methods 0.000 claims abstract description 28
- 238000000034 method Methods 0.000 claims abstract description 25
- 238000001035 drying Methods 0.000 claims abstract description 9
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 claims description 23
- 229910052751 metal Inorganic materials 0.000 claims description 19
- 239000002184 metal Substances 0.000 claims description 19
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 9
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 9
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 claims description 6
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 6
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims description 5
- 229910017604 nitric acid Inorganic materials 0.000 claims description 5
- 239000002245 particle Substances 0.000 claims description 4
- 230000035484 reaction time Effects 0.000 claims description 4
- 229910000147 aluminium phosphate Inorganic materials 0.000 claims description 3
- 239000000377 silicon dioxide Substances 0.000 claims description 3
- 239000011148 porous material Substances 0.000 abstract description 17
- 230000008901 benefit Effects 0.000 abstract description 10
- 238000009826 distribution Methods 0.000 abstract description 6
- 238000005265 energy consumption Methods 0.000 abstract description 4
- 230000000052 comparative effect Effects 0.000 description 21
- 239000000843 powder Substances 0.000 description 21
- 230000000694 effects Effects 0.000 description 14
- 238000006317 isomerization reaction Methods 0.000 description 14
- 150000001335 aliphatic alkanes Chemical class 0.000 description 13
- TVMXDCGIABBOFY-UHFFFAOYSA-N octane Chemical compound CCCCCCCC TVMXDCGIABBOFY-UHFFFAOYSA-N 0.000 description 10
- 238000005303 weighing Methods 0.000 description 10
- 238000012986 modification Methods 0.000 description 9
- 230000004048 modification Effects 0.000 description 9
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical group [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 8
- 238000002360 preparation method Methods 0.000 description 7
- 239000000945 filler Substances 0.000 description 6
- 239000012065 filter cake Substances 0.000 description 6
- 239000000047 product Substances 0.000 description 6
- 238000005086 pumping Methods 0.000 description 6
- 238000003756 stirring Methods 0.000 description 6
- 238000010306 acid treatment Methods 0.000 description 5
- NLXLAEXVIDQMFP-UHFFFAOYSA-N Ammonia chloride Chemical compound [NH4+].[Cl-] NLXLAEXVIDQMFP-UHFFFAOYSA-N 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 4
- 230000003197 catalytic effect Effects 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- ZMANZCXQSJIPKH-UHFFFAOYSA-N Triethylamine Chemical compound CCN(CC)CC ZMANZCXQSJIPKH-UHFFFAOYSA-N 0.000 description 3
- 238000001354 calcination Methods 0.000 description 3
- 238000012512 characterization method Methods 0.000 description 3
- 238000005336 cracking Methods 0.000 description 3
- 239000000706 filtrate Substances 0.000 description 3
- 238000001914 filtration Methods 0.000 description 3
- 230000007935 neutral effect Effects 0.000 description 3
- 229910000510 noble metal Inorganic materials 0.000 description 3
- 239000003755 preservative agent Substances 0.000 description 3
- 230000002335 preservative effect Effects 0.000 description 3
- 238000012216 screening Methods 0.000 description 3
- 238000007789 sealing Methods 0.000 description 3
- 238000003786 synthesis reaction Methods 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 239000002841 Lewis acid Substances 0.000 description 2
- JUJWROOIHBZHMG-UHFFFAOYSA-N Pyridine Chemical compound C1=CC=NC=C1 JUJWROOIHBZHMG-UHFFFAOYSA-N 0.000 description 2
- 239000006004 Quartz sand Substances 0.000 description 2
- 241000219782 Sesbania Species 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- -1 amine cations Chemical class 0.000 description 2
- XKMRRTOUMJRJIA-UHFFFAOYSA-N ammonia nh3 Chemical compound N.N XKMRRTOUMJRJIA-UHFFFAOYSA-N 0.000 description 2
- 235000019270 ammonium chloride Nutrition 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 239000003292 glue Substances 0.000 description 2
- 150000007517 lewis acids Chemical class 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229920000742 Cotton Polymers 0.000 description 1
- PIICEJLVQHRZGT-UHFFFAOYSA-N Ethylenediamine Chemical compound NCCN PIICEJLVQHRZGT-UHFFFAOYSA-N 0.000 description 1
- 238000005033 Fourier transform infrared spectroscopy Methods 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- FKNQFGJONOIPTF-UHFFFAOYSA-N Sodium cation Chemical compound [Na+] FKNQFGJONOIPTF-UHFFFAOYSA-N 0.000 description 1
- 229910021536 Zeolite Inorganic materials 0.000 description 1
- 239000002156 adsorbate Substances 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- 150000001412 amines Chemical class 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 239000002585 base Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- HQABUPZFAYXKJW-UHFFFAOYSA-N butan-1-amine Chemical compound CCCCN HQABUPZFAYXKJW-UHFFFAOYSA-N 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
- 150000001768 cations Chemical class 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 229910052593 corundum Inorganic materials 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000003344 environmental pollutant Substances 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 125000005842 heteroatom Chemical group 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 238000010335 hydrothermal treatment Methods 0.000 description 1
- 230000003116 impacting effect Effects 0.000 description 1
- 238000005470 impregnation Methods 0.000 description 1
- 230000000977 initiatory effect Effects 0.000 description 1
- 239000000543 intermediate Substances 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 238000011068 loading method Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000012188 paraffin wax Substances 0.000 description 1
- 231100000719 pollutant Toxicity 0.000 description 1
- UMJSCPRVCHMLSP-UHFFFAOYSA-N pyridine Natural products COC1=CC=CN=C1 UMJSCPRVCHMLSP-UHFFFAOYSA-N 0.000 description 1
- 238000002119 pyrolysis Fourier transform infrared spectroscopy Methods 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 229910001415 sodium ion Inorganic materials 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- BGQMOFGZRJUORO-UHFFFAOYSA-M tetrapropylammonium bromide Chemical compound [Br-].CCC[N+](CCC)(CCC)CCC BGQMOFGZRJUORO-UHFFFAOYSA-M 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 229910001845 yogo sapphire Inorganic materials 0.000 description 1
- 239000010457 zeolite Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J29/00—Catalysts comprising molecular sieves
- B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
- B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
- B01J29/40—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the pentasil type, e.g. types ZSM-5, ZSM-8 or ZSM-11, as exemplified by patent documents US3702886, GB1334243 and US3709979, respectively
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J29/00—Catalysts comprising molecular sieves
- B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
- B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
- B01J29/40—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the pentasil type, e.g. types ZSM-5, ZSM-8 or ZSM-11, as exemplified by patent documents US3702886, GB1334243 and US3709979, respectively
- B01J29/42—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the pentasil type, e.g. types ZSM-5, ZSM-8 or ZSM-11, as exemplified by patent documents US3702886, GB1334243 and US3709979, respectively containing iron group metals, noble metals or copper
- B01J29/44—Noble metals
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J29/00—Catalysts comprising molecular sieves
- B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
- B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
- B01J29/40—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the pentasil type, e.g. types ZSM-5, ZSM-8 or ZSM-11, as exemplified by patent documents US3702886, GB1334243 and US3709979, respectively
- B01J29/48—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the pentasil type, e.g. types ZSM-5, ZSM-8 or ZSM-11, as exemplified by patent documents US3702886, GB1334243 and US3709979, respectively containing arsenic, antimony, bismuth, vanadium, niobium tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J35/00—Catalysts, in general, characterised by their form or physical properties
- B01J35/60—Catalysts, in general, characterised by their form or physical properties characterised by their surface properties or porosity
- B01J35/61—Surface area
- B01J35/615—100-500 m2/g
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J35/00—Catalysts, in general, characterised by their form or physical properties
- B01J35/60—Catalysts, in general, characterised by their form or physical properties characterised by their surface properties or porosity
- B01J35/63—Pore volume
- B01J35/633—Pore volume less than 0.5 ml/g
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
- B01J37/02—Impregnation, coating or precipitation
- B01J37/0201—Impregnation
- B01J37/0207—Pretreatment of the support
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C5/00—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms
- C07C5/22—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms by isomerisation
- C07C5/27—Rearrangement of carbon atoms in the hydrocarbon skeleton
- C07C5/2767—Changing the number of side-chains
- C07C5/277—Catalytic processes
- C07C5/2775—Catalytic processes with crystalline alumino-silicates, e.g. molecular sieves
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2229/00—Aspects of molecular sieve catalysts not covered by B01J29/00
- B01J2229/10—After treatment, characterised by the effect to be obtained
- B01J2229/18—After treatment, characterised by the effect to be obtained to introduce other elements into or onto the molecular sieve itself
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2229/00—Aspects of molecular sieve catalysts not covered by B01J29/00
- B01J2229/30—After treatment, characterised by the means used
- B01J2229/37—Acid treatment
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- Chemical Kinetics & Catalysis (AREA)
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- Crystallography & Structural Chemistry (AREA)
- Catalysts (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention discloses a modification method of a ZSM-5 molecular sieve and a ZSM-5 molecular sieve catalyst, belonging to the field of catalysts. The modification method of the ZSM-5 molecular sieve comprises the following steps: providing an unfreezed ZSM-5 molecular sieve; placing a ZSM-5 molecular sieve without a template agent in a hypergravity impinging stream-rotating packed bed, heating to a reaction temperature, and adding acid liquor into the hypergravity impinging stream-rotating packed bed through a liquid feeding pipe; and continuously adding deionized water into the hypergravity impinging stream-rotating packed bed through the liquid feeding pipe, washing the ZSM-5 molecular sieve modified by the acid liquor, and then drying to obtain the modified ZSM-5 molecular sieve. The method can obtain the modified ZSM-5 molecular sieve with reasonable acid value distribution and step pore channel structure, and has the advantages of simple process, low energy consumption, low pollution emission and low cost.
Description
Technical Field
The invention relates to the field of catalysts, and particularly relates to a modification method of a ZSM-5 molecular sieve and a ZSM-5 molecular sieve catalyst.
Background
The ZSM-5 molecular sieve is a novel zeolite molecular sieve containing organic amine cations, and the chemical composition of the molecular sieve can be expressed by the mole ratio of oxides: 0.9. + -. 0.2M2/nO:Al2O3:5---100SiO2:ZH2O, wherein M is a cation (alkali metal sodium ion and organic amine ion); n is the valence of the cationCounting; z is from 0 to 40. The ZSM-5 molecular sieve contains two crossed pore channel systems: the unique microporous structures of the longitudinal straight-cylinder type pore channel and the transverse sinusoidal pore channel can provide excellent shape-selective performance for the reaction, but on the other hand, the diffusion and mass transfer of reactants, intermediates and products with larger steric hindrance in the pore channel are limited, so the pore channel of the molecular sieve needs to be adjusted to optimize the pore channel structure of the molecular sieve. In addition, the strong acidity and high acid density of the ZSM-5 molecular sieve can ensure that the corresponding catalyst has high initial activity and is quickly deactivated due to the rapid generation of carbon deposit, and the catalyst has important influences on reaction activity, product selectivity and catalyst life, so the acid property of the ZSM-5 molecular sieve also needs to be properly adjusted to adapt to a specific reaction.
At present, modification of the ZSM-5 molecular sieve generally comprises high-temperature hydrothermal treatment, acid-base modification, heteroatom modification and the like. For example, the related art uses a hydrothermal-citric acid modification method to treat a ZSM-5 molecular sieve, and the basic treatment process is as follows: demoulding agent-ammonium exchange-roasting-high-temperature hydrothermal treatment-citric acid treatment. Removing a template agent generated in the synthesis process of the ZSM-5 molecular sieve by roasting, and then performing ammonium exchange-roasting twice to exchange NaZSM-5 into HZSM-5; then, carrying out high-temperature water heat treatment to partially remove the framework aluminum, reduce the acidity of the molecular sieve and simultaneously achieve the effect of pore expansion, namely modifying the microporous ZSM-5 molecular sieve into a step pore molecular sieve; and finally, treating with citric acid to remove non-framework aluminum in the framework. Finally, the modified ZSM-5 molecular sieve is obtained, and because the acidity of the molecular sieve is reduced, the pore channel is more open, and the acid strength distribution of the molecular sieve tends to be average.
In the process of implementing the invention, the inventor finds that at least the following problems exist in the prior art:
the modification method provided by the related technology has the disadvantages of complicated steps, excessive energy consumption caused by multiple times of roasting, emission of pollutants such as ammonia and acid, and poor environmental protection.
Disclosure of Invention
In view of the above, the present invention provides a modification method of a ZSM-5 molecular sieve and a ZSM-5 molecular sieve catalyst, which can solve the above technical problems.
Specifically, the method comprises the following technical scheme:
in one aspect, an embodiment of the present invention provides a modification method for a ZSM-5 molecular sieve, where the modification method for the ZSM-5 molecular sieve includes: providing an unfreezed ZSM-5 molecular sieve;
placing the ZSM-5 molecular sieve without the template agent in a hypergravity impinging stream-rotating packed bed, heating to the reaction temperature, and adding acid liquor into the hypergravity impinging stream-rotating packed bed through a liquid feeding pipe for reaction;
and after the reaction is finished, continuously adding deionized water into the hypergravity impinging stream-rotating packed bed through the liquid feeding pipe, washing the ZSM-5 molecular sieve modified by the acid liquor, and then drying to obtain the modified ZSM-5 molecular sieve.
In some possible implementations, the silica to alumina ratio of the ZSM-5 molecular sieve without the template is 30 to 60.
In some possible implementations, the rotational speed of the hypergravity impinging stream-rotating packed bed is 800r/min to 2000r/min when the acid solution is used in the reaction with the ZSM-5 molecular sieve without the template agent.
In some possible implementation modes, the acid solution is selected from at least one of nitric acid, hydrochloric acid, citric acid and phosphoric acid, and the mass space velocity of the acid solution is 0.5h-1～8.0h-1。
In some possible implementation manners, when the acid solution is used for reacting with the ZSM-5 molecular sieve without the template agent, the reaction temperature is 400-700 ℃, the temperature is increased to the reaction temperature at the speed of 5-20 ℃/min, and the reaction time is 3-8 h.
In some possible implementation manners, when the ZSM-5 molecular sieve modified by the acid solution is washed by using deionized water, the rotating speed of the supergravity impinging stream-rotating packed bed is 800 r/min-1000 r/min.
In some possible implementation manners, when the ZSM-5 molecular sieve modified by the acid solution is washed by using deionized water, the mass space velocity of the deionized waterIs 3.0h-1～6.0h-1The washing temperature is 100-120 ℃, and the washing time is 10-30 min.
In another aspect, an embodiment of the present invention further provides a ZSM-5 molecular sieve catalyst, where the ZSM-5 molecular sieve catalyst includes: the modified ZSM-5 molecular sieve comprises a modified ZSM-5 molecular sieve and an active component loaded on the modified ZSM-5 molecular sieve;
wherein the modified ZSM-5 molecular sieve is prepared by any one of the modification methods of the ZSM-5 molecular sieve.
In some possible implementations, the active component is selected from at least one of Pt metal, Pd metal, Rh metal, Ni metal, W metal, Mo metal.
In some possible implementations, the ZSM-5 molecular sieve catalyst has a particle size of 20 mesh to 40 mesh.
The technical scheme provided by the embodiment of the invention has the beneficial effects that at least:
the ZSM-5 molecular sieve without the template agent is placed in a hypergravity impinging stream-rotating packed bed to react with acid liquor under the hypergravity condition, so that the modified ZSM-5 molecular sieve with reasonable acid value distribution can be obtained, wherein the B/L value (B/L value) of the modified ZSM-5 molecular sieve
Acid value/Lewis acid value) is less than 0.2, (weak acid value + medium-strong acid value)/strong acid value is more than 3. And the ZSM-5 molecular sieve modified by the acid liquor has a step pore channel structure, and the modified ZSM-5 molecular sieve is used as a carrier to load a catalyst active component, is applied to catalyzing alkane hydroisomerization reaction, and has the advantages of high medium-temperature reaction activity, high alkane isomer selectivity, high double-branched alkane isomer selectivity, high liquid yield and the like. The modification method of the ZSM-5 molecular sieve provided by the embodiment of the invention has the advantages of simple process, low energy consumption (reducing the using amount of acid liquor), low pollution emission (eliminating ammonia nitrogen emission), low cost and the like on the premise of obtaining the modified ZSM-5 molecular sieve with better performance.
Detailed Description
In order to make the technical solutions and advantages of the present invention more clear, embodiments of the present invention will be described in further detail below.
The embodiment of the invention provides a modification method of a ZSM-5 molecular sieve, which comprises the following steps:
step 1, providing a ZSM-5 molecular sieve without a template agent.
And 2, placing the ZSM-5 molecular sieve without the template agent in a hypergravity impinging stream-rotating packed bed, heating to the reaction temperature, and adding acid liquor into the hypergravity impinging stream-rotating packed bed through a liquid feeding pipe for reaction. Wherein the acid solution reaction aims to convert the Na-type molecular sieve into the H-type molecular sieve.
And 3, after the reaction is finished, continuously adding deionized water into the hypergravity impinging stream-rotating packed bed through the liquid feeding pipe, washing the ZSM-5 molecular sieve modified by the acid liquor, and then drying to obtain the modified ZSM-5 molecular sieve. The purpose of washing is to wash away the residual acid solution in the molecular sieve.
The ZSM-5 molecular sieve without the template agent is placed in a hypergravity impinging stream-rotating packed bed to react with acid liquor under the hypergravity condition, so that the modified ZSM-5 molecular sieve with reasonable acid value distribution can be obtained, wherein the B/L value (B/L value) of the modified ZSM-5 molecular sieve
Acid value/Lewis acid value) is less than 0.2, (weak acid value + medium-strong acid value)/strong acid value is more than 3. And the ZSM-5 molecular sieve modified by the acid liquor has a step pore channel structure, and the modified ZSM-5 molecular sieve is used as a carrier to load a catalyst active component, is applied to catalyzing alkane hydroisomerization reaction, and has the advantages of high medium-temperature reaction activity, high alkane isomer selectivity, high double-branched alkane isomer selectivity, high liquid yield and the like. The modification method of the ZSM-5 molecular sieve provided by the embodiment of the invention has the advantages of simple process (reduced acid liquor consumption) and low energy consumption on the premise of obtaining the modified ZSM-5 molecular sieve with better performance,low pollution discharge (eliminating ammonia nitrogen discharge), low cost and the like.
The following is a description of the steps involved in the above modification method of the ZSM-5 molecular sieve:
for step 1, a ZSM-5 molecular sieve without a template is provided, and the ZSM-5 molecular sieve without a template is used as a raw material in the embodiment of the present invention, because a template is usually used to guide the formation of a molecular sieve structure during the synthesis of the ZSM-5 molecular sieve, and the template is usually removed after the synthesis of the molecular sieve to form a smooth pore channel. The traditional preparation process is that firstly, Na-type molecular sieve containing template agent is synthesized, then the template agent is removed by high-temperature roasting, and then the Na-type molecular sieve is converted into H-type molecular sieve by acid exchange. The method provided by the embodiment of the invention can remove the template agent while exchanging acid.
Wherein the template agent is used for guiding all organic amines formed by a ZSM-5 molecular sieve framework, such as tetrapropylammonium bromide, n-butylamine, triethylamine, ethylenediamine and the like. For example, ZSM-5 molecular sieve without a template agent refers to NaZSM-5 molecular sieve.
In some possible implementations, the silica to alumina ratio of the unfrozen ZSM-5 molecular sieve is greater than 20, such as 30 to 60.
In some possible implementations, the rotational speed of the high gravity impinging stream-rotating packed bed is 800r/min to 2000r/min, such as 800r/min, 1000r/min, 1200r/min, 1500r/min, 1700r/min, 2000r/min, etc., when an acid solution is used to react with the ZSM-5 molecular sieve without the template agent.
The rotating speed of the hypergravity impinging stream-rotating packed bed during the acid solution reaction is limited, because the hypergravity impinging stream-rotating packed bed utilizes two high-speed jet streams to impinge oppositely to form an impinging fog surface which enters the rotating packed bed along the radial direction, the acid solution fog surface is further strengthened in the rotating packed bed for mixing reaction, and the high-temperature acid treatment effect is improved through the rotating speed.
In some possible implementations, the acid solution used in embodiments of the present invention is selected from nitric acid, hydrochloric acid, citric acid, phosphorusAt least one acid, and the mass space velocity of the acid liquor is 0.5h-1～8.0h-1The design is adopted to obtain proper jet flow impact fog surface size, droplet particle size and the like, and further obtain better high-temperature acid treatment effect.
In some possible implementations, when acid solution is used to react with ZSM-5 molecular sieve without template, the reaction temperature is 400-700 deg.C, the temperature is raised to the reaction temperature at the rate of 5-20 deg.C/min, and the reaction time is 3-8 h.
For example, the above reaction temperatures include, but are not limited to: 400 deg.C, 450 deg.C, 500 deg.C, 550 deg.C, 600 deg.C, 650 deg.C, 700 deg.C, etc.
Ramp rates include, but are not limited to: 5 ℃/min, 10 ℃/min, 12 ℃/min, 15 ℃/min, 18 ℃/min, 20 ℃/min and the like.
Reaction times include, but are not limited to: 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, etc.
Under the above operation parameters, the acid solution is used for modifying the ZSM-5 molecular sieve without the template agent, so that a better modification effect can be obtained, and the ZSM-5 molecular sieve modified by the acid solution can obtain an expected step pore channel structure.
In some possible implementation manners, when the ZSM-5 molecular sieve modified by the acid solution is washed by using deionized water, the rotating speed of the hypergravity impinging stream-rotating packed bed is 800r/min to 1000r/min, such as 800r/min, 850r/min, 900r/min, 950r/min, 1000r/min, and the like.
The rotating speed of the hypergravity impinging stream-rotating packed bed during deionized water washing is limited, because the hypergravity impinging stream-rotating packed bed utilizes two high-speed jet streams to impinge oppositely to form an impinging fog surface which enters the rotating packed bed along the radial direction, the acid liquor fog surface is further strengthened in the rotating packed bed for mixing reaction, and the high-temperature acid treatment effect is improved through the rotating speed.
In some possible implementation modes, when deionized water is used for washing the ZSM-5 molecular sieve modified by the acid liquor, the mass space velocity of the deionized water is 3.0h-1～6.0h-1Washing ofThe temperature is 100-120 ℃, and the washing time is 10-30 min.
For example, the above washing temperatures include, but are not limited to: 100 ℃, 110 ℃, 120 ℃ and the like.
Wash times include, but are not limited to: 10 minutes, 15 minutes, 20 minutes, 25 minutes, etc.
The mass space velocity of deionized water includes, but is not limited to: 3.0h-1、4.0h-1、5.0h-1、6.0h-1And the like.
The deionized water is washed under the above operation parameters, and a better washing effect can be obtained on the premise of not influencing the structure of the modified ZSM-5 molecular sieve.
In another aspect, an embodiment of the present invention further provides a ZSM-5 molecular sieve catalyst, where the ZSM-5 molecular sieve catalyst includes: the modified ZSM-5 molecular sieve and an active component loaded on the modified ZSM-5 molecular sieve; wherein the modified ZSM-5 molecular sieve is prepared by any one of the modification methods of the ZSM-5 molecular sieve.
The ZSM-5 molecular sieve catalyst provided by the embodiment of the invention uses the modified ZSM-5 molecular sieve prepared by any one of the modification methods of the ZSM-5 molecular sieve, and when the modified ZSM-5 molecular sieve is used as a carrier to load an active component, the modified ZSM-5 molecular sieve can be used for catalyzing alkane hydroisomerization reaction, and has the advantages of effectively improving the selectivity of high-octane-number products such as double-branched-chain products and the like in the aspect of catalytic effect, and further improving the octane number of an isomerized product. Even if the reaction is carried out at a low temperature of 200 ℃, high isomerization selectivity can still be obtained.
In some possible implementations, the active component is selected from at least one of Pt metal, Pd metal, Rh metal, Ni metal, W metal, Mo metal.
The metal is selected, so that the ZSM-5 molecular sieve catalyst can be used for catalyzing alkane hydroisomerization reaction, and a good catalytic effect is obtained.
In some possible implementation modes, the particle size of the ZSM-5 molecular sieve catalyst is 20 meshes to 40 meshes, and the ZSM-5 molecular sieve catalyst with the mesh number has more proper specific surface area, so that the catalytic activity of the catalyst is further improved.
For the preparation of the above ZSM-5 molecular sieve catalyst, see the following steps:
the modified ZSM-5 molecular sieve obtained by the modification method provided by the embodiment of the invention is screened, an isometric impregnation method is adopted to load active components, the active components are naturally dried, and then the ZSM-5 molecular sieve catalyst is obtained by roasting.
Wherein, the screening treatment modes include but are not limited to: and (4) tabletting and screening or extruding and forming and screening.
Further, the ZSM-5 molecular sieve catalyst provided in the embodiments of the present invention further includes: sesbania powder or alumina dry glue. Thus, during preparation, the modified ZSM-5 molecular sieve doped sesbania powder and the alumina dry glue are extruded into strips and then screened.
The catalytic performance of the modified ZSM-5 molecular sieve catalyst provided by the embodiments of the present invention can be evaluated by alkane isomerization, as follows:
5g of modified ZSM-5 molecular sieve catalyst is placed in a catalyst bed layer of a 10mL micro continuous flow fixed bed reactor, quartz sand is filled at the upper end, and an iron wire mesh layer, a quartz cotton layer, a ceramic ball and quartz sand are sequentially filled at the lower end from bottom to top.
N-octane is used as a model compound, and the reaction is carried out according to a certain reaction temperature, reaction pressure, hydrogen-oil volume ratio and mass airspeed.
For example, when the above-described paraffin isomerization reaction is carried out, the respective operating parameters are as follows:
the reaction temperature T is 200 ℃ to 400 ℃, for example, 200 ℃, 250 ℃, 300 ℃, 350 ℃, 400 ℃ and the like;
the reaction pressure P is 1MPa to 2MPa, for example, 1MPa, 1.2MPa, 1.5MPa, 1.7MPa, 2MPa, etc.;
the volume ratio of the hydrogen to the oil is 300-400, such as 300, 320, 340, 350, 370, 380, 400 and the like;
the mass space velocity WHSV is 1.0h-1～2.0h-1For example, 1.0h-1、1.2h-1、1.5h-1、1.7h-1、1.8h-1、2.0h-1And the like.
The following detailed description will be provided for the purpose of illustrating the embodiments and the advantageous effects thereof, and is not intended to limit the scope of the present invention.
Example 1
This example 1 provides a modified ZSM-5 molecular sieve, which is modified by the following method:
weighing a certain amount of NaZSM-5 molecular sieve raw powder without the template-stripping agent, fixing the powder on a hypergravity impinging stream-rotating filler bed, and heating to 480 ℃ by adopting a program of 5 ℃/min.
Setting the rotating speed of the hypergravity impinging stream-rotating packed bed at 1500r/min, circularly pumping dilute hydrochloric acid with the concentration of 0.5mol/L into the hypergravity impinging stream-rotating packed bed by a liquid feed pump through a liquid feed pipe, wherein the mass airspeed is WHSV of 3.0h-1And reacting for 6 hours by using acid liquor.
And after the acid liquor reaction is finished, continuously adding deionized water into the hypergravity impinging stream-rotating packed bed through the liquid feeding pipe, stopping heating, and washing the ZSM-5 molecular sieve modified by the acid liquor. The rotating speed of the hypergravity impinging stream-rotating packed bed is set to be 1000r/min, and the mass airspeed WHSV is set to be 5.0h-1And after washing for 20 minutes, stopping feeding the deionized water, stopping rotating the hypergravity impinging stream-rotating packed bed, heating to 120 ℃, and keeping for 2 hours.
Example 2
This example 2 provides a modified ZSM-5 molecular sieve, which is modified by the following method:
weighing a certain amount of NaZSM-5 molecular sieve raw powder without the template agent, fixing the powder on a hypergravity impinging stream-rotating filler bed, and heating to 550 ℃ by adopting a program of 20 ℃/min.
Setting the rotating speed of the hypergravity impinging stream-rotating packed bed at 2000r/min, circularly pumping dilute hydrochloric acid with the concentration of 2.5mol/L into the hypergravity impinging stream-rotating packed bed by a liquid feed pump through a liquid feed pipe, wherein the mass airspeed is WHSV of 0.5h-1And reacting for 5 hours by using acid liquor.
After the acid liquor reaction is finished, the acid liquor is continuously fed into the reactor through the liquidAnd adding deionized water into the hypergravity impinging stream-rotating packed bed through the material pipe, stopping heating, and washing the ZSM-5 molecular sieve modified by the acid liquor. The rotating speed of the hypergravity impinging stream-rotating packed bed is set to be 1000r/min, and the mass airspeed WHSV is set to be 5.0h-1And after washing for 22 minutes, stopping feeding the deionized water, stopping rotating the hypergravity impinging stream-rotating packed bed, and heating to 115 ℃ for 2 hours.
Example 3
This example 3 provides a modified ZSM-5 molecular sieve, which is modified by the following method:
weighing a certain amount of NaZSM-5 molecular sieve raw powder without the template agent, fixing the powder on a hypergravity impinging stream-rotating filler bed, and heating to 700 ℃ by adopting a program of 15 ℃/min.
Setting the rotating speed of the hypergravity impinging stream-rotating packed bed at 800r/min, circularly pumping dilute nitric acid with the concentration of 1mol/L into the hypergravity impinging stream-rotating packed bed by a liquid feed pump through a liquid feed pipe, wherein the mass airspeed is WHSV of 5h-1And reacting for 3 hours by using acid liquor.
And after the acid liquor reaction is finished, continuously adding deionized water into the hypergravity impinging stream-rotating packed bed through the liquid feeding pipe, stopping heating, and washing the ZSM-5 molecular sieve modified by the acid liquor. Setting the rotating speed of the hypergravity impinging stream-rotating packed bed to be 900r/min and the mass airspeed WHSV to be 5.5h-1And after washing for 25 minutes, stopping feeding the deionized water, stopping rotating the hypergravity impinging stream-rotating packed bed, heating to 115 ℃ and keeping for 2 hours.
Example 4
This example 4 provides a modified ZSM-5 molecular sieve, which is modified by the following method:
weighing a certain amount of NaZSM-5 molecular sieve raw powder without the template agent, fixing the powder on a hypergravity impinging stream-rotating filler bed, and heating to 400 ℃ by adopting a program of 10 ℃/min.
Setting the rotating speed of the hypergravity impinging stream-rotating packed bed to be 1500r/min, circularly pumping dilute nitric acid with the concentration of 0.5mol/L into the hypergravity impinging stream-rotating packed bed by a liquid feed pump through a liquid feed pipe, wherein the mass airspeed is WHSV of 2h-1And reacting for 4 hours by using acid liquor.
And after the acid liquor reaction is finished, continuously adding deionized water into the hypergravity impinging stream-rotating packed bed through the liquid feeding pipe, stopping heating, and washing the ZSM-5 molecular sieve modified by the acid liquor. The rotating speed of the hypergravity impinging stream-rotating packed bed is set to be 1000r/min, and the mass airspeed WHSV is set to be 5.0h-1And after washing for 20 minutes, stopping feeding the deionized water, stopping rotating the hypergravity impinging stream-rotating packed bed, heating to 120 ℃, and keeping for 2 hours.
Example 5
This example 5 provides a modified ZSM-5 molecular sieve, which was modified by the following method:
weighing a certain amount of NaZSM-5 molecular sieve raw powder without the template agent, fixing the powder on a hypergravity impinging stream-rotating filler bed, and heating to 640 ℃ by adopting a program of 10 ℃/min.
Setting the rotating speed of the hypergravity impinging stream-rotating packed bed to be 1800r/min, circularly pumping citric acid with the concentration of 0.1mol/L into the hypergravity impinging stream-rotating packed bed by a liquid feed pump through a liquid feed pipe, wherein the mass airspeed is WHSV of 8h-1And reacting for 4 hours by using acid liquor.
And after the acid liquor reaction is finished, continuously adding deionized water into the hypergravity impinging stream-rotating packed bed through the liquid feeding pipe, stopping heating, and washing the ZSM-5 molecular sieve modified by the acid liquor. Setting the rotating speed of the hypergravity impinging stream-rotating packed bed at 950r/min and the mass airspeed WHSV at 6.0h-1And after washing for 15 minutes, stopping feeding the deionized water, stopping rotating the hypergravity impinging stream-rotating packed bed, heating to 120 ℃, and keeping for 2 hours.
Example 6
This example 6 provides a modified ZSM-5 molecular sieve, which was modified by the following method:
weighing a certain amount of NaZSM-5 molecular sieve raw powder without the template agent, fixing the powder on a hypergravity impinging stream-rotating filler bed, and heating to 550 ℃ by adopting a program of 15 ℃/min.
Setting the rotating speed of the hypergravity impinging stream-rotating packed bed to be 1500r/min, and impacting the hypergravity impinging stream to the hypergravity by a liquid feed pump through a liquid feed pipeThe impact flow-rotating packed bed circularly injects phosphoric acid with the concentration of 0.5mol/L, and the mass space velocity is WHSV of 3h-1And reacting for 4 hours by using acid liquor.
And after the acid liquor reaction is finished, continuously adding deionized water into the hypergravity impinging stream-rotating packed bed through the liquid feeding pipe, stopping heating, and washing the ZSM-5 molecular sieve modified by the acid liquor. The rotating speed of the hypergravity impinging stream-rotating packed bed is set to be 1000r/min, and the mass airspeed WHSV is set to be 4.5h-1And after washing for 20 minutes, stopping feeding the deionized water, stopping rotating the hypergravity impinging stream-rotating packed bed, heating to 110 ℃ and keeping for 2 hours.
Comparative example 1
Preparation of HZSM-5 molecular sieve
The HZSM-5 molecular sieve related to the comparative example 1 is obtained by roasting after traditional ammonium exchange, and the preparation method comprises the following steps:
(1) baking the demoulding agent: weighing a certain amount of NaZSM-5 molecular sieve raw powder without a template agent, placing the raw powder in a muffle furnace, raising the temperature to 550 ℃ by a program of 2 ℃/min, and roasting the raw powder at 550 ℃ for 6 hours to obtain a1。
(2) Ammonium exchange and roasting: weighing a certain amount of the above-mentioned a1Adding 1.0mol/L ammonium chloride solution into a beaker, sealing the beaker by using a preservative film, and fully stirring the beaker, wherein the solid-liquid mass ratio is 1: 10. Stirring continuously for 4h in a constant temperature water bath at 80 ℃. And (3) after the water bath is finished, cooling to room temperature, filtering, washing the filter cake with deionized water until the filtrate is neutral, and finally placing the filter cake in a 120 ℃ oven for drying for 12 hours. Placing in a muffle furnace, heating to 520 deg.C at a temperature of 2 deg.C/min, and calcining at 520 deg.C for 6 hr to obtain a2。
(3) Secondary ammonium exchange and roasting: a is to2Repeating the steps of ammonium exchange and roasting to obtain the HZSM-5 molecular sieve a3。
Comparative example 2
Preparation of non-hypergravity modified ZSM-5 molecular sieve
The method for treating the modified ZSM-5 molecular sieve under the non-hypergravity condition, which is related by the comparative example 2, comprises the following steps:
(1) modifying a ZSM-5 molecular sieve under a non-hypergravity condition: weighingFixing a certain amount of NaZSM-5 molecular sieve raw powder without a template agent on a hypergravity impinging stream-rotating packed bed, heating to 480 ℃ by adopting a program of 5 ℃/min, setting the rotating speed of the hypergravity impinging stream-rotating packed bed to be 0r/min, circularly pumping 0.5mol/L dilute hydrochloric acid by a liquid feed pump, wherein the mass space velocity is WHSV of 3h-1Reacting for 4h to obtain b1。
(2) Washing and drying: changing liquid feeding into deionized water and stopping heating, setting the rotating speed of a supergravity device at 1000r/min and the mass airspeed at WHSV of 5.0h-1After washing for 20min, stopping liquid feeding, stopping rotation, heating to 120 ℃ and keeping for 2h to obtain b2。
Comparative example 3
The comparative example relates to a traditional modified ZSM-5 molecular sieve treatment method, which comprises the following steps:
(1) baking the demoulding agent: weighing a certain amount of commercial ZSM-5 molecular sieve raw powder, placing the raw powder in a muffle furnace, raising the temperature to 550 ℃ at a program of 2 ℃/min, and roasting the raw powder for 6 hours at 550 ℃ to obtain c1。
(2) Ammonium exchange and roasting: weighing a certain amount of the above c1Adding 1.0mol/L ammonium chloride solution into a beaker, sealing the beaker by using a preservative film, and fully stirring the beaker, wherein the solid-liquid mass ratio is 1: 10. Stirring continuously for 4h in a constant temperature water bath at 80 ℃. And (3) after the water bath is finished, cooling to room temperature, filtering, washing a filter cake by deionized water until the filtrate is neutral, and finally placing the filter cake in a 120 ℃ oven for drying for 12 hours. Placing in a muffle furnace, heating to 520 deg.C at a temperature of 2 deg.C/min, and calcining at 520 deg.C for 6 hr to obtain c2。
(3) Secondary ammonium exchange and roasting: c is to2Repeating the ammonium exchange and calcination steps to obtain c3。
(4) Hydrothermal modification: c above3Molecular sieve at 480 deg.C and WHSV of 1h-1Introducing 100% of water vapor for treatment for 4h to obtain c4。
(5) And (3) citric acid treatment: c above4Placing the mixture into a beaker, adding 1.2mol/L citric acid with the solid-liquid mass ratio of 1:10, sealing the mixture by using a preservative film, and fully stirring the mixture. Stirring is continuously carried out for 6h in a constant temperature water bath at 65 ℃. Water bathCooling to room temperature after the reaction is finished, filtering, washing the filter cake with deionized water until the filtrate is neutral, and finally placing the filter cake in a drying oven at 120 ℃ for drying for 12h to obtain c5。
Test example 1
In order to prove the technical effect of the method provided by the embodiment of the invention on the regulation and control of the acid property distribution (distribution of B acid and L acid) of the modified ZSM-5 molecular sieve, pyridine IS used as an adsorbate, a Nicolet IS50 type Fourier transform infrared spectrometer of Thermal Fisher company in America IS adopted to measure the contents of the B acid and the L acid of the modified ZSM-5 molecular sieve provided by the above embodiments and the proportion, and the test results are shown in Table 1.
TABLE 1 Py-FTIR characterization results of ZSM-5 molecular sieves treated in each example and comparative example
As can be seen from Table 1, the acidity and acid content of the sample of comparative example 3, which had undergone the conventional hydrothermal modification method, were greatly improved, but the acid content of B was still high, and the B/L value was 0.6, which easily caused cracking, compared to the acid content of HZSM-5 obtained in comparative example 1. The modified ZSM-5 molecular sieve provided by the embodiments 1-6 of the invention has greatly reduced B acid amount, properly increased L acid amount and greatly reduced strong acid amount, wherein the B/L ratio is lower than 0.2, and the ratio of (weak acid + medium strong acid)/strong acid is larger than 3.
Test example 2
In order to prove the technical effect of the scheme provided by the embodiment of the invention on the regulation and control of the pore channel structure of the ZSM-5 molecular sieve, the structural parameters such as the specific surface area, the pore structure and the like of the various modified ZSM-5 molecular sieves are measured by adopting a full-automatic adsorption instrument of ASAP 2460 model of Mciromerics company in America, and the results are shown in Table 2.
TABLE 2 BET characterisation results of ZSM-5 molecular sieves treated in each example and comparative example
As can be seen from the data in Table 2, the modified ZSM-5 molecular sieves of examples 1-6 of the present invention provide a greater improvement in the specific surface and pore volume than the conventional HZSM-5 prior to modification (provided in comparative example 1). The conventional modification methods (comparative example 2 and comparative example 3) also have some improvement in the channel structure, but have a gap compared with the examples of the present invention.
Test example 3
The above examples and comparative examples were prepared as catalysts according to Table 3, respectively, and used to catalyze the isomerization of paraffins under different conditions, and the results of the catalytic reactions obtained are shown in Table 4.
As can be seen from the data in Table 4, the catalyst using the modified ZSM-5 molecular sieve as the carrier provided by the embodiment of the invention has excellent ability for catalyzing the isomerization reaction of the alkane at medium temperature, even if the catalyst is reacted at a low temperature of 200 ℃, the conversion rate can still reach more than 70%, and the total isomerization selectivity reaches 90%. Wherein, under the reaction condition of 200 ℃, the conversion rate of n-octane of the catalyst provided by the embodiment 1 reaches 70.6 percent, the total selectivity of isomerization is still maintained at 78.3 percent, the selectivity of C8 double-branched chain reaches 12.0 percent, and the yield of C8 double-branched chain isomer reaches 8.4 percent.
EXAMPLE 3 the modified ZSM-5 molecular sieve obtained by the modification method of the present invention has a high isomerization performance even under the condition of loading non-noble metals such as Ni/Mo.
③ the carrier modification of comparative example 1 caused cracking reaction because the acidity was not improved.
And fourthly, the catalyst of the comparative example 2 is modified under the condition of non-supergravity, and the catalyst of the comparative example 3 adopts the traditional modification mode of the ZSM-5 molecular sieve, so that the acid property of the molecular sieve is improved to a certain extent, the octane isomerization selectivity is improved, but the effect is far worse than that of the catalyst of the modified ZSM-5 carrier obtained by the invention.
As can be seen from table 4, compared with various proportions, the catalyst using the modified ZSM-5 molecular sieve provided in the embodiment of the present invention as a carrier has higher alkane isomer selectivity, double-branched alkane isomer selectivity, and liquid yield, and has significant advantages in isomerization performance. Therefore, the catalyst using the modified ZSM-5 molecular sieve obtained by the modification method of the embodiment of the invention as the carrier has higher reaction activity, high isomerization selectivity and more excellent isomerization performance even if Ni/Mo non-noble metal is used as the reaction at the low temperature of 200 ℃ of the dehydrogenation center. In addition, the catalyst prepared by the modification method provided by the embodiment of the invention can use non-noble metal as an active component, has the advantages of simple process, low pollution emission, energy conservation and low cost, and has good economic benefit and industrialization potential.
TABLE 3 preparation of catalysts and conditions applied to isomerization of alkanes
TABLE 4 characterization results for n-octane isomerization for each example and comparative example
| X％ | SMB | SDB | S | S＜C8 | Y | YDB | |
| Example 1 | 70.6 | 78.3 | 12.0 | 90.2 | 9.8 | 63.7 | 8.4 |
| Example 2 | 70.5 | 78.6 | 11.9 | 90.5 | 9.5 | 63.8 | 8.4 |
| Example 3 | 79.8 | 76.9 | 11.9 | 88.8 | 11.2 | 70.9 | 9.5 |
| Example 4 | 84.3 | 69.4 | 12.8 | 82.2 | 17.8 | 69.3 | 10.8 |
| Example 5 | 85.1 | 58.3 | 12.4 | 70.7 | 29.3 | 60.1 | 10.5 |
| Example 6 | 79.6 | 77.5 | 11.8 | 89.3 | 10.7 | 71.1 | 9.4 |
| Comparative example 1 | 91.2 | 8.5 | 1.4 | 9.9 | 90.1 | 9.1 | 1.3 |
| Comparative example 2 | 70.5 | 35.2 | 2.0 | 37.2 | 62.8 | 26.2 | 1.4 |
| Comparative example 3 | 77.2 | 39.5 | 2.3 | 41.8 | 58.2 | 32.3 | 1.8 |
Remarking: (ii) X-n-octane conversion; sMB-single branched octane isomer selectivity; sDB-double branched octane isomer selectivity; the total selectivity of S-iso-octane products; s＜C8-cracking selectivity; yield of the Y-octane isomer; y isDBYield of double branched octane isomers.
The above description is only for the convenience of understanding the technical solutions of the present invention by those skilled in the art, and is not intended to limit the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A modification method of a ZSM-5 molecular sieve is characterized by comprising the following steps: providing a ZSM-5 molecular sieve without a template agent;
placing the ZSM-5 molecular sieve without the template agent in a hypergravity impinging stream-rotating packed bed, heating to the reaction temperature, and adding acid liquor into the hypergravity impinging stream-rotating packed bed through a liquid feeding pipe for reaction;
and after the reaction is finished, continuously adding deionized water into the hypergravity impinging stream-rotating packed bed through the liquid feeding pipe, washing the ZSM-5 molecular sieve modified by the acid liquor, and then drying to obtain the modified ZSM-5 molecular sieve.
2. The method for modifying the ZSM-5 molecular sieve of claim 1, wherein the silica to alumina ratio of the ZSM-5 molecular sieve without the template is 30 to 60.
3. The method for modifying the ZSM-5 molecular sieve of claim 1, wherein the rotational speed of the hypergravity impinging stream-rotating packed bed is 800r/min to 2000r/min when the acid solution is used for reacting with the ZSM-5 molecular sieve without the template agent.
4. The modification method of the ZSM-5 molecular sieve of claim 1, wherein the acid solution is selected from at least one of nitric acid, hydrochloric acid, citric acid and phosphoric acid, and the mass space velocity of the acid solution is 0.5h-1～8.0h-1。
5. The method for modifying the ZSM-5 molecular sieve of claim 1, wherein when the acid solution is used to react with the ZSM-5 molecular sieve without the template agent, the reaction temperature is 400 ℃ to 700 ℃, the temperature is increased to the reaction temperature at a rate of 5 ℃/min to 20 ℃/min, and the reaction time is 3h to 8 h.
6. The method for modifying the ZSM-5 molecular sieve of claim 1, wherein the rotating speed of the hypergravity impinging stream-rotating packed bed is 800r/min to 1000r/min when the ZSM-5 molecular sieve modified by the acid solution is washed by deionized water.
7. The ZSM-5 molecular sieve modification method of claim 6, wherein the mass space velocity of deionized water is 3.0h when the ZSM-5 molecular sieve modified by the acid solution is washed by the deionized water-1～6.0h-1The washing temperature is 100-120 ℃, and the washing time is 10-30 min.
8. A ZSM-5 molecular sieve catalyst, wherein the ZSM-5 molecular sieve catalyst comprises: the modified ZSM-5 molecular sieve comprises a modified ZSM-5 molecular sieve and an active component loaded on the modified ZSM-5 molecular sieve;
wherein the modified ZSM-5 molecular sieve is prepared by the method of modifying a ZSM-5 molecular sieve according to any one of claims 1 to 7.
9. The ZSM-5 molecular sieve catalyst as claimed in claim 8, wherein the active component is selected from at least one of Pt metal, Pd metal, Rh metal, Ni metal, W metal, Mo metal.
10. The ZSM-5 molecular sieve catalyst as claimed in claim 8 or 9, wherein the ZSM-5 molecular sieve catalyst has a particle size of 20-40 mesh.
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| US20080103272A1 (en) * | 2004-06-25 | 2008-05-01 | Chen Yuan-Ju Ray | Reactor Systems for use in Polymerization Processes |
| US20130129576A1 (en) * | 2010-04-02 | 2013-05-23 | Nanjing University | Multiphase catalytic tower-type impinging-stream reactor |
| CN106564908A (en) * | 2016-11-14 | 2017-04-19 | 中北大学 | Method for microwave synthesis of ZSM-5 molecular sieve by means of strengthening of impinging stream-rotating packed bed |
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