CN107321344B - Honeycomb denitration catalyst with improved specific surface area and preparation method thereof - Google Patents
Honeycomb denitration catalyst with improved specific surface area and preparation method thereof Download PDFInfo
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- 239000003054 catalyst Substances 0.000 title claims abstract description 150
- 238000002360 preparation method Methods 0.000 title claims abstract description 40
- 239000002243 precursor Substances 0.000 claims abstract description 62
- 238000002156 mixing Methods 0.000 claims abstract description 52
- 239000000843 powder Substances 0.000 claims abstract description 43
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 43
- 238000003756 stirring Methods 0.000 claims abstract description 41
- 239000002002 slurry Substances 0.000 claims abstract description 40
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims abstract description 37
- 229910052720 vanadium Inorganic materials 0.000 claims abstract description 37
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 claims abstract description 37
- 239000010936 titanium Substances 0.000 claims abstract description 35
- 229910052719 titanium Inorganic materials 0.000 claims abstract description 35
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims abstract description 34
- 239000000463 material Substances 0.000 claims abstract description 31
- 238000001035 drying Methods 0.000 claims abstract description 28
- 238000000034 method Methods 0.000 claims abstract description 27
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims abstract description 21
- 229910001930 tungsten oxide Inorganic materials 0.000 claims abstract description 21
- 229910052721 tungsten Inorganic materials 0.000 claims abstract description 18
- 239000010937 tungsten Substances 0.000 claims abstract description 18
- 238000001914 filtration Methods 0.000 claims abstract description 15
- 238000005406 washing Methods 0.000 claims abstract description 15
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 14
- 239000011248 coating agent Substances 0.000 claims abstract description 13
- 238000000576 coating method Methods 0.000 claims abstract description 13
- 230000001376 precipitating effect Effects 0.000 claims abstract description 12
- 238000004537 pulping Methods 0.000 claims abstract description 10
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 claims abstract description 7
- 229910052750 molybdenum Inorganic materials 0.000 claims abstract description 7
- 239000011733 molybdenum Substances 0.000 claims abstract description 7
- 239000012065 filter cake Substances 0.000 claims abstract description 6
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N titanium dioxide Inorganic materials O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 26
- QGLKJKCYBOYXKC-UHFFFAOYSA-N nonaoxidotritungsten Chemical compound O=[W]1(=O)O[W](=O)(=O)O[W](=O)(=O)O1 QGLKJKCYBOYXKC-UHFFFAOYSA-N 0.000 claims description 17
- 238000007789 sealing Methods 0.000 claims description 15
- 239000008367 deionised water Substances 0.000 claims description 12
- 229910021641 deionized water Inorganic materials 0.000 claims description 12
- 239000002245 particle Substances 0.000 claims description 11
- 230000010355 oscillation Effects 0.000 claims description 9
- 239000011148 porous material Substances 0.000 claims description 3
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 claims description 3
- 229920003171 Poly (ethylene oxide) Polymers 0.000 claims description 2
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 claims description 2
- 239000004202 carbamide Substances 0.000 claims description 2
- 238000010907 mechanical stirring Methods 0.000 claims description 2
- -1 polyoxyethylene Polymers 0.000 claims description 2
- 244000275012 Sesbania cannabina Species 0.000 claims 1
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 abstract description 11
- 239000003546 flue gas Substances 0.000 abstract description 11
- 230000008021 deposition Effects 0.000 abstract description 8
- 229910001385 heavy metal Inorganic materials 0.000 abstract 1
- QAOWNCQODCNURD-UHFFFAOYSA-N sulfuric acid group Chemical group S(O)(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 26
- 238000004523 catalytic cracking Methods 0.000 description 21
- 239000002699 waste material Substances 0.000 description 19
- UNTBPXHCXVWYOI-UHFFFAOYSA-O azanium;oxido(dioxo)vanadium Chemical compound [NH4+].[O-][V](=O)=O UNTBPXHCXVWYOI-UHFFFAOYSA-O 0.000 description 15
- 238000006243 chemical reaction Methods 0.000 description 14
- APUPEJJSWDHEBO-UHFFFAOYSA-P ammonium molybdate Chemical compound [NH4+].[NH4+].[O-][Mo]([O-])(=O)=O APUPEJJSWDHEBO-UHFFFAOYSA-P 0.000 description 13
- 239000011609 ammonium molybdate Substances 0.000 description 13
- 229940010552 ammonium molybdate Drugs 0.000 description 13
- 235000018660 ammonium molybdate Nutrition 0.000 description 13
- XAYGUHUYDMLJJV-UHFFFAOYSA-Z decaazanium;dioxido(dioxo)tungsten;hydron;trioxotungsten Chemical compound [H+].[H+].[NH4+].[NH4+].[NH4+].[NH4+].[NH4+].[NH4+].[NH4+].[NH4+].[NH4+].[NH4+].O=[W](=O)=O.O=[W](=O)=O.O=[W](=O)=O.O=[W](=O)=O.O=[W](=O)=O.O=[W](=O)=O.[O-][W]([O-])(=O)=O.[O-][W]([O-])(=O)=O.[O-][W]([O-])(=O)=O.[O-][W]([O-])(=O)=O.[O-][W]([O-])(=O)=O.[O-][W]([O-])(=O)=O XAYGUHUYDMLJJV-UHFFFAOYSA-Z 0.000 description 13
- 229910000349 titanium oxysulfate Inorganic materials 0.000 description 13
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 12
- 235000011114 ammonium hydroxide Nutrition 0.000 description 12
- 241000219782 Sesbania Species 0.000 description 11
- 230000000052 comparative effect Effects 0.000 description 11
- JKQOBWVOAYFWKG-UHFFFAOYSA-N molybdenum trioxide Inorganic materials O=[Mo](=O)=O JKQOBWVOAYFWKG-UHFFFAOYSA-N 0.000 description 11
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 9
- 230000008569 process Effects 0.000 description 9
- WKXHZKXPFJNBIY-UHFFFAOYSA-N titanium tungsten vanadium Chemical compound [Ti][W][V] WKXHZKXPFJNBIY-UHFFFAOYSA-N 0.000 description 9
- XHCLAFWTIXFWPH-UHFFFAOYSA-N [O-2].[O-2].[O-2].[O-2].[O-2].[V+5].[V+5] Chemical group [O-2].[O-2].[O-2].[O-2].[O-2].[V+5].[V+5] XHCLAFWTIXFWPH-UHFFFAOYSA-N 0.000 description 8
- 229910001935 vanadium oxide Inorganic materials 0.000 description 8
- 239000013078 crystal Substances 0.000 description 7
- 230000000694 effects Effects 0.000 description 7
- 238000010009 beating Methods 0.000 description 5
- 238000000975 co-precipitation Methods 0.000 description 5
- 239000002253 acid Substances 0.000 description 4
- 230000003197 catalytic effect Effects 0.000 description 4
- 238000011156 evaluation Methods 0.000 description 4
- 238000011065 in-situ storage Methods 0.000 description 4
- MAKDTFFYCIMFQP-UHFFFAOYSA-N titanium tungsten Chemical compound [Ti].[W] MAKDTFFYCIMFQP-UHFFFAOYSA-N 0.000 description 4
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 description 3
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 3
- 239000013543 active substance Substances 0.000 description 3
- 230000007547 defect Effects 0.000 description 3
- 239000006185 dispersion Substances 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 239000003344 environmental pollutant Substances 0.000 description 3
- 229910044991 metal oxide Inorganic materials 0.000 description 3
- 229910000476 molybdenum oxide Inorganic materials 0.000 description 3
- PQQKPALAQIIWST-UHFFFAOYSA-N oxomolybdenum Chemical compound [Mo]=O PQQKPALAQIIWST-UHFFFAOYSA-N 0.000 description 3
- 231100000719 pollutant Toxicity 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 238000001027 hydrothermal synthesis Methods 0.000 description 2
- 239000011261 inert gas Substances 0.000 description 2
- 150000004706 metal oxides Chemical class 0.000 description 2
- 229910003455 mixed metal oxide Inorganic materials 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 238000012216 screening Methods 0.000 description 2
- 239000004408 titanium dioxide Substances 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 238000004220 aggregation Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- XKMRRTOUMJRJIA-UHFFFAOYSA-N ammonia nh3 Chemical compound N.N XKMRRTOUMJRJIA-UHFFFAOYSA-N 0.000 description 1
- 238000010531 catalytic reduction reaction Methods 0.000 description 1
- 238000012512 characterization method Methods 0.000 description 1
- 239000003245 coal Substances 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000006477 desulfuration reaction Methods 0.000 description 1
- 230000023556 desulfurization Effects 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 238000012854 evaluation process Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000004927 fusion Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 229910052602 gypsum Inorganic materials 0.000 description 1
- 239000010440 gypsum Substances 0.000 description 1
- 229910010272 inorganic material Inorganic materials 0.000 description 1
- 239000011147 inorganic material Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 239000002105 nanoparticle Substances 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 235000006408 oxalic acid Nutrition 0.000 description 1
- ZFUASHFORHAKBU-UHFFFAOYSA-N oxygen(2-) titanium(4+) trioxotungsten Chemical compound [W](=O)(=O)=O.[O-2].[O-2].[Ti+4] ZFUASHFORHAKBU-UHFFFAOYSA-N 0.000 description 1
- 238000005504 petroleum refining Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000006722 reduction reaction Methods 0.000 description 1
- 238000013341 scale-up Methods 0.000 description 1
- 239000000779 smoke Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- ZNOKGRXACCSDPY-UHFFFAOYSA-N tungsten(VI) oxide Inorganic materials O=[W](=O)=O ZNOKGRXACCSDPY-UHFFFAOYSA-N 0.000 description 1
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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
- B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
- B01J23/16—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
- B01J23/24—Chromium, molybdenum or tungsten
- B01J23/30—Tungsten
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/86—Catalytic processes
- B01D53/8621—Removing nitrogen compounds
- B01D53/8625—Nitrogen oxides
- B01D53/8628—Processes characterised by a specific catalyst
-
- 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
- B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
- B01J23/002—Mixed oxides other than spinels, e.g. perovskite
-
- 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
- B01J35/50—Catalysts, in general, characterised by their form or physical properties characterised by their shape or configuration
- B01J35/56—Foraminous structures having flow-through passages or channels, e.g. grids or three-dimensional monoliths
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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
- 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
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2258/00—Sources of waste gases
- B01D2258/02—Other waste gases
- B01D2258/0283—Flue gases
-
- 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
- B01J2523/00—Constitutive chemical elements of heterogeneous catalysts
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- Materials Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Organic Chemistry (AREA)
- Environmental & Geological Engineering (AREA)
- Health & Medical Sciences (AREA)
- Biomedical Technology (AREA)
- Analytical Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
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- Exhaust Gas Treatment By Means Of Catalyst (AREA)
Abstract
The invention discloses a honeycomb denitration catalyst with improved specific surface area and a preparation method thereof, and the preparation method comprises the following steps: (1) pulping the activated alumina; (2) dissolving a titanium source precursor; (3) dissolving a tungsten source precursor, and mixing the tungsten source precursor with the materials in the steps (1) and (2); (4) uniformly mixing the materials obtained in the step (3), adjusting the pH value of the materials to 8-13, precipitating, filtering and washing to obtain a filter cake; (5) adding water into the filter cake obtained in the step (4), mixing into slurry, adding a vanadium source precursor solution, mixing, drying and roasting to form powder; (6) and (3) mixing the solution formed by the molybdenum source precursor and the powder in the step (5) into slurry, stirring, adding a pore-forming agent, stirring for the second time, standing, extruding into a honeycomb shape, drying, coating the surface with nano-tungsten oxide, and roasting to obtain the denitration catalyst. The denitration catalyst prepared by the method can improve the specific surface area of the catalyst and resist the uneven deposition of heavy metals in flue gas on the surface of the denitration catalyst.
Description
Technical Field
The invention relates to a honeycomb denitration catalyst with an improved specific surface area and a preparation method thereof, in particular to a denitration catalyst capable of resisting uneven vanadium deposition in flue gas and a preparation method thereof, and belongs to the technical field of novel inorganic materials.
Background
Nitrogen Oxides (NO)x) Is one of the main atmospheric pollutants, and the emission requirements are increasingly strict. The stipulation in the 'twelve five' comprehensive working scheme for energy conservation and emission reduction in China is as follows: by 2015, the total national nitrogen oxide emissions were reduced by 10% compared to 2010. GB13223-2001 'atmospheric pollutant emission standard of thermal power plant' issued by the national environmental protection department in 9 months 2011 makes more strict requirements on NOx emission concentration of the thermal power plant: the newly built, expanded and reconstructed coal-fired boiler is specified in the third period of time, and the maximum allowable NOx emission concentration is 100mg/m3. The requirements of the emission standard of pollutants for petroleum refining industry issued by the national environmental protection department are as follows: beginning at 7 months and 1 day in 2015, the requirement of nitrogen oxide in regenerated flue gas discharged by newly-built catalytic cracking device is less than 200mg/m3Particular emission limits of less than 100mg/m3Existing enterprises of 7/1/2017 also implement the standard. Among the various flue gas denitration technologies, Selective Catalytic Reduction (SCR) is still the mainstream technology in the world, and NO thereofxThe removal rate can reach 80-90%. Among them, the denitration catalyst is the core of the SCR technology, developed countries developed a series of denitration catalysts aiming at the characteristics of coal quality, boiler type and the like in the last 80 th century, and many scientific research units and enterprises in China also carried out a series of researches aiming at the conditions of coal-fired boilers and catalytic cracking flue gas in China and developed some denitration catalysts.
CN201010537130 proposes a method for preparing a denitration catalyst by using a hydrothermal method, which comprises mixing a titanium source precursor and a tungsten source precursor, placing the mixture in an autoclave for hydrothermal reaction, filtering, washing and drying to obtain a titanium-tungsten powder denitration catalyst, and introducing vanadium, molybdenum and other elements to prepare a multi-metal oxide catalyst. The active component of the catalyst prepared by the method has small crystal grains and larger specific surface area, but the phenomenon of higher aggregation degree of the same materials can be caused because the active component is not fully mixed, and the activity of the catalyst can be influenced to a certain extent.
CN201110345605 provides a preparation method of a denitration catalyst, which comprises sequentially adding ammonium tungstate, ammonium molybdate and ammonium metavanadate into metatitanic acid slurry, performing ultrasonic pulping, adjusting the pH value to 4.0-6.5, standing, separating and drying to obtain catalyst powder. The method has simple process and low cost, but ammonium metavanadate is added as a solid, the solubility of vanadium is to be verified, and SO is high in activity although the vanadium is not uniformly dispersed2/SO3The conversion rate is higher, and the use performance of the catalyst is influenced.
CN201210400949 proposes a preparation method of titanium dioxide-tungsten trioxide composite powder, which is to add ammonium paratungstate solution into metatitanic acid slurry, stir and directly vacuum-dry to obtain a finished product. The method has simple process, but the titanium-tungsten mixing strength is lower, and the performance of the material is influenced to a certain extent.
In summary, the preparation of the denitration catalyst involves the mixing of various metal oxides, and the difference of the mixing mode and the process cannot completely distinguish the denitration performance of the catalyst, NOxThe conversion rate can reach more than 90 percent, which shows that the catalytic activity of the specific metal oxide is higher, and higher NO can still be obtained due to uneven dispersionxAnd (4) conversion rate. The quality of the overall performance of the catalyst needs to be verified from other aspects of characterization, and the preparation of the catalyst also needs to be compatible with the operability of industrial scale-up.
Disclosure of Invention
The invention mainly aims to provide a honeycomb denitration catalyst with improved specific surface area and a preparation method thereof, so as to overcome the defect of unbalanced active centers of the denitration catalyst in high-temperature flue gas in the prior art, and the catalyst can resist the uneven deposition of vanadium oxide in the flue gas on the surface, increase the specific surface area of the catalyst and improve the performance of the catalyst.
The invention aims to realize the purpose, the honeycomb denitration catalyst with the improved specific surface area and the preparation method thereof, and the preparation method comprises the following steps:
(1) pulping the activated alumina;
(2) dissolving a titanium source precursor to form a solution;
(3) dissolving a tungsten source precursor, and uniformly mixing the tungsten source precursor with the solution obtained in the step (1) and the step (2);
(4) uniformly mixing the solution obtained in the step (3), adjusting the pH value of the solution to 8-13, precipitating, filtering and washing to obtain a filter cake;
(5) adding deionized water into the filter cake obtained in the step (4), mixing into a slurry, adding a vanadium source precursor solution, mixing uniformly, drying, and roasting to form a powder;
(6) and (3) mixing the solution formed by the molybdenum source precursor and the powder in the step (5) into slurry, stirring, adding a pore-forming agent, stirring for the second time, sealing, standing, extruding into a honeycomb shape, drying, coating the surface with nano-tungsten oxide, and roasting to form the denitration catalyst.
In the invention, the titanium source precursor, the tungsten source precursor, the vanadium source precursor, the pore-forming agent and the activated alumina are all used substances commonly used for preparing the denitration catalyst in the prior art, and the dosage is also selected according to the process characteristics, but the invention is not particularly limited. The invention also recommends a preferred scheme.
The activated alumina in the step (1) of the invention has a particle size of 10-500 meshes, preferably 180-400 meshes, and a specific surface area of 60-200 m2The pore volume is preferably 0.40-0.80 cm/g3/g。
In the method, the active alumina mass and titanium source precursor (TiO) in the step (1)2In terms of) 3 to 20:100, preferably 3 to 10: 100.
In the preparation method of the denitration catalyst, the titanium source precursor in the step (2) is preferably titanyl sulfate or metatitanic acid, the titanium source precursor is dissolved, and the solvent is preferably sulfuric acid, water, nitric acid or oxalic acid.
In the preparation method of the denitration catalyst, the tungsten source precursor in the step (3) is preferably ammonium paratungstate orAmmonium metatungstate, tungsten source precursor and tungsten oxide precursor3The precursor of the titanium source is calculated as TiO2Preferably, the mass ratio of the tungsten source precursor to the titanium source precursor used in the step (3) is 2.0-5.0: 100.
The preparation method of the denitration catalyst comprises the steps of (3), (5) and (6) adopting mechanical stirring and mixing, hydrodynamic mixing or \ and ultrasonic oscillation mixing, wherein the mixing time of the steps of (3) and (5) is preferably 0.5-3 h, the mixing time of the step of (6) is preferably 10-60 min, and the sealing and standing time of the step of (6) is preferably 8-30 h.
In the preparation method of the denitration catalyst, the agent used for adjusting the pH value in the step (4) is preferably ammonia water or potassium hydroxide, and the adjusted pH value is preferably 8-13.
In the preparation method of the denitration catalyst, a vanadium source precursor in the vanadium source precursor solution in the step (5) is preferably ammonium metavanadate or ammonium vanadate, and the vanadium source precursor is represented by V2O5The precursor of the titanium source is TiO2The mass ratio of the vanadium source precursor to the titanium source precursor is preferably 1.0-6.0: 100.
The preparation method of the denitration catalyst provided by the invention is characterized in that the roasting temperature in the step (5) and the roasting time in the step (6) are both preferably 400-650 ℃, and the roasting time is preferably 4-10 h.
In the preparation method of the denitration catalyst, the molybdenum source precursor in the step (6) is preferably ammonium molybdate, and MoO is used as the molybdenum source precursor3The precursor of the titanium source is calculated as TiO2The mass ratio of the molybdenum source precursor to the titanium source precursor is preferably 0.5-2: 100.
The preparation method of the denitration catalyst comprises the step (6), wherein the pore-forming agent added in the step (6) is preferably one or more of urea, polyoxyethylene and sesbania powder, and the mass ratio of the added pore-forming agent to the titanium source precursor is preferably 0.5-1.5: 100.
The preparation method of the denitration catalyst comprises the step (6) of preparing the nano tungsten oxideIn the amount of WO3The precursor of the titanium source is calculated as TiO2The mass ratio of the tungsten oxide to the titanium source precursor is 1-10: 100, preferably 3-6: 100.
The invention also provides a denitration catalyst, which is prepared by the preparation method of the denitration catalyst.
The invention has the beneficial effects that:
(1) in the preparation process of the catalyst, the active alumina is adopted, and the interior of the active alumina is provided with rich nano-scale micropores, so that the active sites in the catalyst are increased. After the active alumina is mixed with the titanium and the tungsten in the ionic state, amorphous titanium oxide and tungsten oxide can be promoted to wrap the active alumina more tightly, the strength of the catalyst is improved, and the specific surface area of the catalyst (the specific surface area is 130 m) is also improved due to the use of the active alumina2More than g) and porosity, improves the efficiency of the catalyst, does not need the protection of inert gas in the preparation process of the catalyst, and reduces the preparation cost.
(2) By utilizing an in-situ mixing method, titanium atoms and tungsten atoms are mixed at an atomic level, so that crystals generated in a subsequent coprecipitation process have more lattice defects, the particle size of mixed metal oxides is small and uniform, the specific surface area is large, the crystal transition temperature of titanium dioxide crystals is increased, and the exertion of catalytic activity is facilitated;
(3) the method of ultrasonic-assisted mixing is adopted, so that the mixing of various materials at the atomic level is more uniform;
(4) the vanadium source is added when the active alumina, the titanium source and the tungsten source coprecipitation material are not roasted, the vanadium source penetrates deeper on the surface of the titanium-tungsten particles, the connection is tighter, the dispersion is more uniform, the active sites are more, and the activity of the catalyst is more stable after roasting;
(5) after the prepared vanadium-tungsten-titanium powder material is roasted for one time, a layer of molybdenum oxide is covered on the surface of the vanadium-tungsten-titanium powder material, and meanwhile, a pore-forming agent is added, so that the surface of catalyst particles has more tungsten oxide adhesion, and meanwhile, the vanadium-tungsten-titanium powder material also has rich space network-shaped nano-scale micropores and higher specific surface area and crushing strength, not only can be used for resisting the uneven deposition of vanadium oxide on the surface of the vanadium-tungsten-titanium powder material in flue gas, but also can be.
(6) After the catalyst is formed and dried, a layer of nano-scale tungsten oxide is coated on the surface of the catalyst, so that the performance of the catalyst is improved.
Detailed Description
The following examples illustrate the invention in detail: the present example is carried out on the premise of the technical scheme of the present invention, and detailed embodiments and processes are given, but the scope of the present invention is not limited to the following examples, and the experimental methods without specific conditions noted in the following examples are generally performed according to conventional conditions.
Titanium source precursor solution:
in the present invention, the titanium source precursor is dissolved in sulfuric acid to form a solution, and the titanium source precursor is not particularly limited, but is usually limited to titanyl sulfate or metatitanic acid, and the solution of the titanium source precursor is made of TiO2The content of the titanium source precursor is preferably 15-40 g/L. If the concentration is less than 15g/L, the solution is too dilute, the combination with other materials is loose, and the production efficiency is low; if it exceeds 40g/L, the mixing strength with other materials is lowered due to too high concentration, resulting in poor fusion.
The mixing process of the catalyst sample and the catalytic cracking waste catalyst comprises the following steps: crushing the prepared fresh catalyst, and screening to obtain 20-40 mesh powder; screening catalytic cracking waste catalysts (LDC series) and taking 40-60 mesh powder, wherein the content of vanadium oxide in the catalytic cracking waste catalysts is about 1%. The two powders were mixed at a mass ratio of 1:1, mixed at 350 ℃ for 24 hours in an air atmosphere, and then sieved to obtain catalyst powders for evaluation. In the process of contacting and mixing the fresh catalyst and the waste catalytic cracking catalyst, active substances vanadium in the waste catalytic cracking catalyst are unevenly transferred to the fresh catalyst, SO that the active substances vanadium oxide on the surface of the fresh catalyst are intensively accumulated, the local activity of the catalyst is enhanced, and the SO of the catalyst is increased2/SO3The conversion rate and the overall performance of the denitration catalyst are reduced.
NOxConversion evaluation conditions: space velocity of 20000h-1Reaction temperature of 350 ℃ and inlet gas NOx600mg/Nm3、SO2Is 1000mg/Nm3Ammonia to nitrogen ratio of 1, water contentThe amount was 10%.
NOx、SO2The concentration measuring method comprises the following steps: a continuous on-line flue gas analyzer, siemens ULTRAMAT 23.
SO2/SO3The conversion rate determination method comprises the following steps: limestone-gypsum wet flue gas desulfurization device performance acceptance test specification (DL/T998-2006).
The following examples are specific illustrations of the present invention, and "%" described in examples and comparative examples means mass percent.
Activated alumina: the particle size is 300 meshes, the specific surface area is 120m2G, pore volume of 70cm3/g。
Example 1:
adding water to 20g of activated alumina, beating to form a slurry, and adding TiO2A total of 500g of titanyl sulfate was dissolved in the sulfuric acid solution to form a TiO-containing solution2At 35g/L of solution, a solution containing WO was added3Measuring 10g of ammonium paratungstate solution, oscillating for 2 hours by ultrasonic wave, gradually adding ammonia water to adjust the pH value to 9.5, precipitating completely, filtering and washing; then the washed materials are made into slurry with the water content of 50 percent by deionized water, and V is added2O5Measuring 5g of ammonium metavanadate solution, stirring and simultaneously carrying out ultrasonic oscillation for 1.5h, directly drying, and roasting at the temperature of 620 ℃ for 6 h; mixing the calcined powder with MoO3Preparing slurry containing 30% of water from 10g of ammonium molybdate, adding 4g of sesbania powder after stirring, stirring for 40min, sealing and standing for 24h, extruding into a honeycomb shape, drying, coating 15g of nano tungsten oxide, and roasting at 600 ℃ for 8h to obtain the denitration catalyst. The specific surface area of the catalyst is 136m2(ii) in terms of/g. The obtained fresh catalyst and the catalyst after being mixed with the catalytic cracking vanadium-containing waste catalyst at high temperature are respectively evaluated, and the results are shown in the data of table 1.
Comparative example 1:
in the preparation process of the catalyst, active alumina is not added, namely TiO is added2A total of 500g of titanyl sulfate was dissolved in the sulfuric acid solution to form a TiO-containing solution2At 35g/L of solution, a solution containing WO was added3Metering 10g of ammonium paratungstate solution, oscillating for 2 hours by ultrasonic wave, gradually adding ammonia water to adjust the pH value to 9.5, filtering after complete precipitation,Washing; then the washed materials are made into slurry with the water content of 50 percent by deionized water, and V is added2O5Measuring 5g of ammonium metavanadate solution, stirring and simultaneously carrying out ultrasonic oscillation for 1.5h, directly drying, and roasting at the temperature of 620 ℃ for 6 h; mixing the calcined powder with MoO3Preparing 10g of ammonium molybdate solution into slurry containing 30% of water, adding 4g of sesbania powder after stirring, stirring for 40min, sealing and standing for 24h, extruding into a honeycomb shape, drying, coating 15g of nano tungsten oxide, and roasting at 600 ℃ for 8h to obtain the denitration catalyst. The specific surface area of the catalyst is 122m2(ii) in terms of/g. The obtained fresh catalyst and the catalyst after being mixed with the catalytic cracking vanadium-containing waste catalyst at high temperature are respectively evaluated, and the results are shown in the data of table 1.
Example 2
Adding water to 40g of activated alumina, beating to form a slurry, and adding TiO2A total of 500g of titanyl sulfate was dissolved in the sulfuric acid solution to form a TiO-containing solution2Adding a solution containing WO at a concentration of 40g/L3Measuring 15g of ammonium paratungstate solution, oscillating for 1h by ultrasonic wave, gradually adding ammonia water to adjust the pH value to 9.0, precipitating completely, filtering and washing; then the washed materials are made into slurry with the water content of 50 percent by deionized water, and V is added2O5Measuring 20g of ammonium metavanadate solution, stirring and simultaneously carrying out ultrasonic oscillation for 1.5h, directly drying, and roasting at 400 ℃ for 6 h; mixing the calcined powder with MoO3Preparing slurry containing 30% of water from 3g of ammonium molybdate, adding 4g of sesbania powder after stirring, stirring for 40min, sealing and standing for 10h, extruding into a honeycomb shape, drying, coating 25g of nano tungsten oxide, and roasting at 500 ℃ for 8h to obtain the denitration catalyst. The obtained fresh catalyst and the catalyst after being mixed with the catalytic cracking vanadium-containing waste catalyst at high temperature are respectively evaluated, and the results are shown in the data of table 1.
Comparative example 2
Adding no nano-tungsten oxide in the preparation process of the catalyst, namely adding 40g of active alumina, fully mixing and pulping to form slurry, and adding TiO2A total of 500g of titanyl sulfate was dissolved in the sulfuric acid solution to form a TiO-containing solution2Adding a solution containing WO at a concentration of 40g/L3Measuring 40g of ammonium paratungstate solution, and ultrasonically oscillatingGradually adding ammonia water after 1h to adjust the pH value to 9.0, filtering and washing after complete precipitation; then the washed materials are made into slurry with the water content of 50 percent by deionized water, and V is added2O5Measuring 20g of ammonium metavanadate solution, stirring and simultaneously carrying out ultrasonic oscillation for 1.5h, directly drying, and roasting at 400 ℃ for 6 h; mixing the calcined powder with MoO3Preparing slurry containing 30% of water by using 3g of ammonium molybdate solution, adding 4g of sesbania powder after stirring, stirring for 40min, sealing and standing for 10h, extruding into a honeycomb shape, drying, and roasting at 500 ℃ for 8h to obtain the denitration catalyst. The obtained fresh catalyst and the catalyst after being mixed with the catalytic cracking vanadium-containing waste catalyst at high temperature are respectively evaluated, and the results are shown in the data of table 1.
Example 3
Adding 20g of activated alumina to water, beating to form a slurry, and adding TiO2A total of 500g of titanyl sulfate was dissolved in the sulfuric acid solution to form a TiO-containing solution2Adding a solution containing WO at a concentration of 40g/L3Measuring 12.5g of ammonium paratungstate solution, oscillating for 3 hours by ultrasonic wave, gradually adding ammonia water to adjust the pH value to 10.5, precipitating completely, filtering and washing; then the washed materials are made into slurry with the water content of 35 percent by deionized water, and V is added2O5Measuring 30g of ammonium metavanadate solution, stirring and simultaneously carrying out ultrasonic oscillation for 1.5h, directly drying, and roasting at 400 ℃ for 6 h; mixing the calcined powder with MoO3Preparing slurry containing 30% of water from 3g of ammonium molybdate, adding 4g of sesbania powder after stirring, stirring for 40min, sealing and standing for 10h, extruding into a honeycomb shape, drying, coating 25g of nano tungsten oxide, and roasting at 500 ℃ for 8h to obtain the denitration catalyst. The obtained fresh catalyst and the catalyst after being mixed with the catalytic cracking vanadium-containing waste catalyst at high temperature are respectively evaluated, and the results are shown in the data of table 1.
Comparative example 3
Adding a vanadium source after the first roasting, namely: adding 20g of activated alumina to water, beating to form a slurry, and adding TiO2A total of 500g of titanyl sulfate was dissolved in the sulfuric acid solution to form a TiO-containing solution2Adding a solution containing WO at a concentration of 40g/L3Measuring 12.5g ammonium paratungstate solution, oscillating for 3h with ultrasonic wave, gradually adding ammonia water for blendingAdjusting the pH value to 10.5, completely precipitating, filtering, washing, drying, and roasting at 400 ℃ for 6 hours; adding V into the calcined powder2O530g of ammonium metavanadate solution are added with MoO3Preparing slurry containing 30% of water from 3g of ammonium molybdate, adding 4g of sesbania powder after stirring, stirring for 40min, sealing and standing for 10h, extruding into a honeycomb shape, drying, coating 25g of nano tungsten oxide, and roasting at 500 ℃ for 8h to obtain the denitration catalyst. The obtained fresh catalyst and the catalyst after being mixed with the catalytic cracking vanadium-containing waste catalyst at high temperature are respectively evaluated, and the results are shown in the data of table 1.
Example 4
Adding 50g of activated alumina to water, beating to form a slurry, and adding TiO2A total of 500g of titanyl sulfate was dissolved in the sulfuric acid solution to form a TiO-containing solution2Adding a solution containing WO at a concentration of 40g/L3Measuring 25g of ammonium paratungstate solution, mechanically stirring for 3h, gradually adding ammonia water to adjust the pH value to 10.5, completely precipitating, filtering and washing; then the washed materials are made into slurry with the water content of 35 percent by deionized water, and V is added2O5Measuring 30g of ammonium metavanadate solution, mechanically stirring for 0.5h, directly drying, and roasting at 650 ℃ for 6 h; mixing the calcined powder with MoO3Preparing slurry containing 30% of water from 2.5g of ammonium molybdate, stirring, adding 2.5g of sesbania powder, stirring for 40min, sealing and standing for 10h, extruding into a honeycomb shape, drying, coating 15g of nano tungsten oxide, and roasting at 650 ℃ for 8h to obtain the denitration catalyst. The obtained fresh catalyst and the catalyst after being mixed with the catalytic cracking vanadium-containing waste catalyst at high temperature are respectively evaluated, and the results are shown in the data of table 1.
Comparative example 4
The catalyst is prepared by roasting only once, i.e. adding 50g of activated alumina into water, pulping to form a slurry, and adding TiO2A total of 500g of titanyl sulfate was dissolved in the sulfuric acid solution to form a TiO-containing solution2Adding a solution containing WO at a concentration of 40g/L3Measuring 25g of ammonium paratungstate solution, mechanically stirring for 3h, gradually adding ammonia water to adjust the pH value to 10.5, completely precipitating, filtering and washing; then the washed materials are made into slurry with the water content of 35 percent by deionized water, and the slurry is addedWith V2O530g of ammonium metavanadate solution are mechanically stirred for 0.5h and then mixed with MoO3Preparing slurry containing 30% of water from 2.5g of ammonium molybdate, stirring, adding 2.5g of sesbania powder, stirring for 40min, sealing and standing for 10h, extruding into a honeycomb shape, drying, coating 15g of nano tungsten oxide, and roasting at 650 ℃ for 8h to obtain the denitration catalyst. The obtained fresh catalyst and the catalyst after being mixed with the catalytic cracking vanadium-containing waste catalyst at high temperature are respectively evaluated, and the results are shown in the data of table 1.
Example 5
Pulping 15g of activated alumina to form a slurry, and adding TiO2A total of 500g of titanyl sulfate was dissolved in the sulfuric acid solution to form a TiO-containing solution2At 35g/L of solution, a solution containing WO was added3Measuring 10g of ammonium paratungstate solution, mechanically stirring for 0.5h, gradually adding ammonia water to adjust the pH value to 9.0, precipitating completely, filtering and washing; then the washed materials are made into slurry with the water content of 35 percent by deionized water, and V is added2O5Measuring 5g of ammonium metavanadate solution, stirring and simultaneously carrying out ultrasonic oscillation for 0.5h, directly drying, and roasting at 400 ℃ for 6 h; mixing the calcined powder with MoO3Preparing slurry containing 35% of water from 10g of ammonium molybdate, adding 7.5g of sesbania powder after stirring, stirring for 40min, sealing and standing for 10h, extruding into a honeycomb shape, drying, coating 30g of nano tungsten oxide, and roasting at 400 ℃ for 8h to obtain the denitration catalyst. The obtained fresh catalyst and the catalyst after being mixed with the catalytic cracking vanadium-containing waste catalyst at high temperature are respectively evaluated, and the results are shown in the data of table 1.
Comparative example 5
Pulping 15g of activated alumina to form a slurry without adding pore-forming agent after primary roasting, and adding TiO2A total of 500g of titanyl sulfate was dissolved in the sulfuric acid solution to form a TiO-containing solution2At 35g/L of solution, a solution containing WO was added3Measuring 10g of ammonium paratungstate solution, mechanically stirring for 0.5h, gradually adding ammonia water to adjust the pH value to 9.0, precipitating completely, filtering and washing; then the washed materials are made into slurry with the water content of 35 percent by deionized water, and V is added2O5Measuring 5g ammonium metavanadate solution, stirring while ultrasonic oscillating for 0.5h, directly dryingRoasting at 400 deg.c for 6 hr; mixing the calcined powder with MoO3Preparing slurry containing 35% of water from 10g of ammonium molybdate, stirring for 40min, sealing and standing for 10h, extruding into a honeycomb shape, drying, coating 30g of nano tungsten oxide, and roasting at 400 ℃ for 8h to obtain the denitration catalyst. The obtained fresh catalyst and the catalyst after being mixed with the catalytic cracking vanadium-containing waste catalyst at high temperature are respectively evaluated, and the results are shown in the data of table 1.
Example 6
Pulping 30g of activated alumina to form a slurry, and adding TiO2A total of 500g of titanyl sulfate was dissolved in the sulfuric acid solution to form a TiO-containing solution2At 35g/L of solution, a solution containing WO was added3Measuring 17.5g of ammonium paratungstate solution, oscillating for 2 hours by ultrasonic wave, gradually adding ammonia water to adjust the pH value to 9.5, precipitating completely, filtering and washing; then the washed materials are made into slurry with the water content of 40 percent by deionized water, and V is added2O5Measuring 15g of ammonium metavanadate solution, stirring and simultaneously carrying out ultrasonic oscillation for 2 hours, directly drying, and roasting at 530 ℃ for 6 hours; mixing the calcined powder with MoO3Preparing slurry containing 35% of water from 5g of ammonium molybdate, adding 5g of sesbania powder after stirring, stirring for 40min, sealing and standing for 20h, extruding into a honeycomb shape, drying, coating 20g of nano tungsten oxide, and roasting at 520 ℃ for 8h to obtain the denitration catalyst. The obtained fresh catalyst and the catalyst after being mixed with the catalytic cracking vanadium-containing waste catalyst at high temperature are respectively evaluated, and the results are shown in the data of table 1.
TABLE 1 comparative table of evaluation data of examples and comparative examples
By way of examples and comparative examples it was found that: the denitration catalyst for resisting uneven vanadium deposition has a good effect, the mixing level of active substances reaches the molecular level through in-situ ultrasonic mixing, slightly-dispersed nano particles are obtained through coprecipitation, vanadium oxide is introduced into the particle surface and the shallow layer, a catalyst intermediate is obtained through roasting, then a cocatalyst is introduced through strengthening under the action of a pore-forming agent, and the catalyst is obtained through roastingTo obtain the final catalyst, NO in catalyst evaluationxThe conversion rate of the catalyst can reach more than 99 percent when the ammonia nitrogen ratio is 1, and SO is obtained after the catalyst is mixed with the catalytic cracking vanadium-containing waste catalyst2/SO3The conversion rate is hardly increased, which shows that the surface of the catalyst hardly generates polycrystalline deposition of vanadium oxide, and the catalyst has excellent performance; in the preparation method of the denitration catalyst, if the denitration catalyst is not treated in the step (6), only the vanadium-tungsten-titanium catalyst sample after the first roasting is reserved, and SO is added after the catalytic cracking of the vanadium-containing waste catalyst2/SO3The conversion rate is slightly increased; if no pore-forming agent is added in the step (6), SO is added after the catalytic cracking vanadium-containing waste catalyst is mixed and treated2/SO3The conversion rate is slightly increased; if the catalyst is prepared by one-time roasting in the preparation process, or the vanadium source is added after one-time roasting, NO in the evaluation process of the catalystxWith a slight decrease in the conversion of SO2/SO3The conversion increased slightly. In summary, when the fresh denitration catalyst and the treated catalyst prepared by the invention are evaluated under the same conditions, SO is2/SO3The conversion rate is lower than that of other comparative samples, and the effect of resisting the uneven deposition of vanadium oxide in smoke is good.
As can be seen from the specific surface area data of the examples and the comparative examples, the specific surface area of the catalyst is obviously increased and the catalytic efficiency is further improved in the in-situ preparation process of adding the activated alumina into the catalyst after pulping.
The invention has the beneficial effects that:
(1) in the preparation process of the catalyst, the active alumina is adopted, and the interior of the active alumina is provided with rich nano-scale micropores, so that the active sites in the catalyst are increased. After the active alumina is mixed with the titanium and the tungsten in the ionic state, amorphous titanium oxide and tungsten oxide can be promoted to wrap the active alumina more tightly, the strength of the catalyst is improved, the specific surface area and the porosity of the catalyst are improved, the efficiency of the catalyst is improved, meanwhile, the inert gas protection is not needed in the preparation process of the catalyst, and the preparation cost is reduced.
(2) By utilizing an in-situ mixing method, titanium atoms and tungsten atoms are mixed at a molecular level, so that crystals generated in a subsequent coprecipitation process have more lattice defects, the particle size of mixed metal oxides is small and uniform, the specific surface area is large, the crystal transition temperature of titanium dioxide crystals is increased, and the exertion of catalytic activity is facilitated;
(3) the method of ultrasonic-assisted mixing is adopted, so that the mixing of various materials at the atomic level is more uniform;
(4) the vanadium source is added when the active alumina, the titanium source and the tungsten source coprecipitation material are not roasted, the vanadium source penetrates deeper on the surface of the titanium-tungsten particles, the connection is tighter, the dispersion is more uniform, the active sites are more, and the activity of the catalyst is more stable after roasting;
(5) after the prepared vanadium-tungsten-titanium powder material is roasted for one time, a layer of molybdenum oxide is covered on the surface of the vanadium-tungsten-titanium powder material, and meanwhile, a pore-forming agent is added, so that the surface of catalyst particles has more molybdenum oxide adhesion, and meanwhile, the vanadium-tungsten-titanium powder material also has rich space network-shaped nano-scale micropores and higher specific surface area and crushing strength, not only can be used for resisting the uneven deposition of vanadium oxide on the surface of the vanadium-tungsten-titanium powder material in flue gas, but also can be.
The present invention is capable of other embodiments, and various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (12)
1. A preparation method of a honeycomb denitration catalyst with improved specific surface area is characterized by comprising the following steps:
(1) adding water into activated alumina, and pulping;
(2) dissolving a titanium source precursor to form a solution;
(3) dissolving a tungsten source precursor, and uniformly mixing the tungsten source precursor with the materials in the steps (1) and (2);
(4) adjusting the pH value of the solution uniformly mixed in the step (3) to 8-13, precipitating, filtering and washing to obtain a filter cake;
(5) adding deionized water into the filter cake obtained in the step (4), mixing into a slurry, adding a vanadium source precursor solution, mixing uniformly, drying, and roasting to form a powder;
(6) and (3) mixing the solution formed by the molybdenum source precursor and the powder in the step (5) into slurry, stirring, adding a pore-forming agent, stirring for the second time, sealing, standing, extruding into a honeycomb shape, drying, coating with nano-tungsten oxide, and roasting to form the denitration catalyst.
2. The preparation method according to claim 1, wherein the activated alumina in the step (1) has a particle size of 10 to 500 meshes and a specific surface area of 60 to 200m2A pore volume of 0.40-0.80 cm/g3/g。
3. The preparation method according to claim 2, wherein the particle size of the activated alumina in the step (1) is 180-400 meshes.
4. The method according to claim 1, wherein the step (3) of mixing the materials comprises mixing activated alumina with TiO2The mass ratio of the titanium source precursor is 3-20: 100.
5. The method according to claim 4, wherein the activated alumina is mixed with TiO in the step (3)2The mass ratio of the titanium source precursor is 3-10: 100.
6. The method according to claim 1, wherein in the step (3), the tungsten source precursor is selected from the group consisting of WO3The precursor of the titanium source is calculated as TiO2The mass ratio of the tungsten source precursor to the titanium source precursor is 2.0-5.0: 100.
7. The preparation method of claim 1, wherein the mixing modes in the step (3), the step (5) and the step (6) are mechanical stirring mixing, hydrodynamic mixing or \ and ultrasonic oscillation mixing, the mixing time of the step (3) and the step (5) is 0.5-3 h, the mixing time of the step (6) is 10-60 min, and the sealing standing time of the step (6) is 8-30 h.
8. The method according to claim 1, wherein the vanadium source precursor in the vanadium source precursor solution of step (5) is represented by V2O5The precursor of the titanium source is calculated as TiO2And the mass ratio of the vanadium source precursor to the titanium source precursor is 1-6: 100.
9. The method according to claim 1, wherein in the step (6), the precursor of the titanium source is TiO2And the mass ratio of the addition amount of the nano-scale tungsten oxide to the titanium source precursor is 3-6: 100.
10. The preparation method of claim 1, wherein the roasting temperature in the step (5) and the roasting time in the step (6) are both 400-650 ℃ and 4-10 h.
11. The preparation method of claim 1, wherein the pore-forming agent is one or more of urea, polyoxyethylene and sesbania powder, and the pore-forming agent is added in an amount corresponding to that of TiO2The mass ratio of the titanium source precursor is 0.5-1.5: 100.
12. A honeycomb denitration catalyst with an increased specific surface area, which is prepared by the method for preparing a honeycomb denitration catalyst with an increased specific surface area according to any one of claims 1 to 11.
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