CN115555002A - Denitration catalyst and preparation method thereof - Google Patents
Denitration catalyst and preparation method thereof Download PDFInfo
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- CN115555002A CN115555002A CN202110746822.4A CN202110746822A CN115555002A CN 115555002 A CN115555002 A CN 115555002A CN 202110746822 A CN202110746822 A CN 202110746822A CN 115555002 A CN115555002 A CN 115555002A
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- 239000003054 catalyst Substances 0.000 title claims abstract description 157
- 238000002360 preparation method Methods 0.000 title claims abstract description 28
- 239000000243 solution Substances 0.000 claims abstract description 124
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 61
- 239000000843 powder Substances 0.000 claims abstract description 56
- 239000002243 precursor Substances 0.000 claims abstract description 56
- 238000002156 mixing Methods 0.000 claims abstract description 55
- 238000001035 drying Methods 0.000 claims abstract description 48
- 239000002002 slurry Substances 0.000 claims abstract description 45
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims abstract description 40
- 239000010936 titanium Substances 0.000 claims abstract description 38
- 229910052719 titanium Inorganic materials 0.000 claims abstract description 38
- 238000001914 filtration Methods 0.000 claims abstract description 35
- 238000005406 washing Methods 0.000 claims abstract description 35
- 239000008367 deionised water Substances 0.000 claims abstract description 29
- 229910021641 deionized water Inorganic materials 0.000 claims abstract description 29
- 239000012065 filter cake Substances 0.000 claims abstract description 29
- 230000001376 precipitating effect Effects 0.000 claims abstract description 27
- 229910052720 vanadium Inorganic materials 0.000 claims abstract description 26
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 claims abstract description 26
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 22
- 239000013078 crystal Substances 0.000 claims abstract description 20
- 239000002270 dispersing agent Substances 0.000 claims abstract description 19
- 238000000227 grinding Methods 0.000 claims abstract description 16
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 14
- 239000002253 acid Substances 0.000 claims abstract description 12
- 239000011259 mixed solution Substances 0.000 claims abstract description 11
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims abstract description 10
- 238000000034 method Methods 0.000 claims description 29
- 229910010413 TiO 2 Inorganic materials 0.000 claims description 25
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 claims description 23
- UNTBPXHCXVWYOI-UHFFFAOYSA-O azanium;oxido(dioxo)vanadium Chemical compound [NH4+].[O-][V](=O)=O UNTBPXHCXVWYOI-UHFFFAOYSA-O 0.000 claims description 18
- 229910000349 titanium oxysulfate Inorganic materials 0.000 claims description 17
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims description 17
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 claims description 16
- 229910052750 molybdenum Inorganic materials 0.000 claims description 16
- 239000011733 molybdenum Substances 0.000 claims description 16
- 229910052721 tungsten Inorganic materials 0.000 claims description 16
- 239000010937 tungsten Substances 0.000 claims description 16
- 229910018072 Al 2 O 3 Inorganic materials 0.000 claims description 15
- DIZPMCHEQGEION-UHFFFAOYSA-H aluminium sulfate (anhydrous) Chemical group [Al+3].[Al+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O DIZPMCHEQGEION-UHFFFAOYSA-H 0.000 claims description 15
- 229920002401 polyacrylamide Polymers 0.000 claims description 7
- 229920000642 polymer Polymers 0.000 claims description 5
- 239000002202 Polyethylene glycol Substances 0.000 claims description 4
- 229920001223 polyethylene glycol Polymers 0.000 claims description 4
- QGAVSDVURUSLQK-UHFFFAOYSA-N ammonium heptamolybdate Chemical compound N.N.N.N.N.N.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.[Mo].[Mo].[Mo].[Mo].[Mo].[Mo].[Mo] QGAVSDVURUSLQK-UHFFFAOYSA-N 0.000 claims description 3
- XUFUCDNVOXXQQC-UHFFFAOYSA-L azane;hydroxy-(hydroxy(dioxo)molybdenio)oxy-dioxomolybdenum Chemical compound N.N.O[Mo](=O)(=O)O[Mo](O)(=O)=O XUFUCDNVOXXQQC-UHFFFAOYSA-L 0.000 claims description 3
- XAYGUHUYDMLJJV-UHFFFAOYSA-Z decaazanium;dioxido(dioxo)tungsten;hydron;trioxotungsten Chemical group [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 claims description 3
- 150000007522 mineralic acids Chemical class 0.000 claims description 3
- 238000001354 calcination Methods 0.000 claims description 2
- -1 polyethylene pyrrolidone Polymers 0.000 claims description 2
- 238000004519 manufacturing process Methods 0.000 claims 1
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 abstract description 21
- 230000000694 effects Effects 0.000 abstract description 21
- 239000003546 flue gas Substances 0.000 abstract description 21
- 230000007547 defect Effects 0.000 abstract description 15
- 239000003513 alkali Substances 0.000 abstract description 6
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 68
- 238000003756 stirring Methods 0.000 description 45
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 36
- 238000006243 chemical reaction Methods 0.000 description 31
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 26
- 239000000463 material Substances 0.000 description 21
- 238000011156 evaluation Methods 0.000 description 18
- 239000000758 substrate Substances 0.000 description 16
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 13
- 235000011114 ammonium hydroxide Nutrition 0.000 description 13
- 239000000428 dust Substances 0.000 description 12
- 230000000052 comparative effect Effects 0.000 description 10
- 229920000036 polyvinylpyrrolidone Polymers 0.000 description 10
- 235000013855 polyvinylpyrrolidone Nutrition 0.000 description 10
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- 238000005303 weighing Methods 0.000 description 6
- APUPEJJSWDHEBO-UHFFFAOYSA-P ammonium molybdate Chemical compound [NH4+].[NH4+].[O-][Mo]([O-])(=O)=O APUPEJJSWDHEBO-UHFFFAOYSA-P 0.000 description 5
- 239000011609 ammonium molybdate Substances 0.000 description 5
- 229940010552 ammonium molybdate Drugs 0.000 description 5
- 235000018660 ammonium molybdate Nutrition 0.000 description 5
- AZDRQVAHHNSJOQ-UHFFFAOYSA-N alumane Chemical group [AlH3] AZDRQVAHHNSJOQ-UHFFFAOYSA-N 0.000 description 4
- 230000009286 beneficial effect Effects 0.000 description 4
- 239000002245 particle Substances 0.000 description 4
- MSOUIOOSDCFNQJ-UHFFFAOYSA-N [Mo].[W].[Ti] Chemical compound [Mo].[W].[Ti] MSOUIOOSDCFNQJ-UHFFFAOYSA-N 0.000 description 3
- 230000009471 action Effects 0.000 description 3
- 238000004523 catalytic cracking Methods 0.000 description 3
- 230000003197 catalytic effect Effects 0.000 description 3
- 239000006185 dispersion Substances 0.000 description 3
- 239000003344 environmental pollutant Substances 0.000 description 3
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- 238000002386 leaching Methods 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 231100000719 pollutant Toxicity 0.000 description 3
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 2
- 239000005977 Ethylene Substances 0.000 description 2
- XHCLAFWTIXFWPH-UHFFFAOYSA-N [O-2].[O-2].[O-2].[O-2].[O-2].[V+5].[V+5] Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[V+5].[V+5] XHCLAFWTIXFWPH-UHFFFAOYSA-N 0.000 description 2
- 229910000287 alkaline earth metal oxide Inorganic materials 0.000 description 2
- UQZIWOQVLUASCR-UHFFFAOYSA-N alumane;titanium Chemical compound [AlH3].[Ti] UQZIWOQVLUASCR-UHFFFAOYSA-N 0.000 description 2
- XKMRRTOUMJRJIA-UHFFFAOYSA-N ammonia nh3 Chemical compound N.N XKMRRTOUMJRJIA-UHFFFAOYSA-N 0.000 description 2
- 238000000975 co-precipitation Methods 0.000 description 2
- 239000000084 colloidal system Substances 0.000 description 2
- 238000005336 cracking Methods 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 238000001027 hydrothermal synthesis Methods 0.000 description 2
- 229910044991 metal oxide Inorganic materials 0.000 description 2
- 229910003455 mixed metal oxide Inorganic materials 0.000 description 2
- 230000008929 regeneration Effects 0.000 description 2
- 238000011069 regeneration method Methods 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 239000013589 supplement Substances 0.000 description 2
- 229910001935 vanadium oxide Inorganic materials 0.000 description 2
- 239000011149 active material Substances 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 238000004220 aggregation Methods 0.000 description 1
- 238000010531 catalytic reduction reaction Methods 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000012512 characterization method Methods 0.000 description 1
- 238000006477 desulfuration reaction Methods 0.000 description 1
- 230000023556 desulfurization Effects 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 238000007499 fusion processing Methods 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
- 239000012535 impurity Substances 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 229910000480 nickel oxide Inorganic materials 0.000 description 1
- 238000000643 oven drying Methods 0.000 description 1
- GNRSAWUEBMWBQH-UHFFFAOYSA-N oxonickel Chemical compound [Ni]=O GNRSAWUEBMWBQH-UHFFFAOYSA-N 0.000 description 1
- 238000005504 petroleum refining Methods 0.000 description 1
- 238000004537 pulping Methods 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 238000013341 scale-up Methods 0.000 description 1
- 238000012216 screening Methods 0.000 description 1
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- 239000000779 smoke Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- MAKDTFFYCIMFQP-UHFFFAOYSA-N titanium tungsten Chemical compound [Ti].[W] MAKDTFFYCIMFQP-UHFFFAOYSA-N 0.000 description 1
- LSGOVYNHVSXFFJ-UHFFFAOYSA-N vanadate(3-) Chemical compound [O-][V]([O-])([O-])=O LSGOVYNHVSXFFJ-UHFFFAOYSA-N 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
- 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
- B01J21/00—Catalysts comprising the elements, oxides, or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium, or hafnium
- B01J21/06—Silicon, titanium, zirconium or hafnium; Oxides or hydroxides thereof
- B01J21/063—Titanium; Oxides or hydroxides thereof
-
- 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
- B01J37/0009—Use of binding agents; Moulding; Pressing; Powdering; Granulating; Addition of materials ameliorating the mechanical properties of the product catalyst
- B01J37/0018—Addition of a binding agent or of material, later completely removed among others as result of heat treatment, leaching or washing,(e.g. forming of pores; protective layer, desintegrating by heat)
-
- 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
- B01J37/03—Precipitation; Co-precipitation
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Materials Engineering (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)
- Catalysts (AREA)
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
Abstract
The invention discloses a preparation method of a denitration catalyst, which comprises the following steps: dissolving a titanium source precursor in acid to form a titanium source precursor solution; dissolving an aluminum source precursor to form a solution, and uniformly mixing the solution with a titanium source precursor solution to obtain a mixed solution; adjusting the pH value of the mixed solution to 7-11, precipitating, filtering, washing and drying to form primary anatase crystal form powder; mixing the primary anatase crystal form powder with a strong alkali solution to form slurry, precipitating, filtering and washing to obtain a filter cake; adding deionized water into the filter cake to prepare slurry, adding the active component solution, uniformly mixing, drying, roasting, and grinding into powder; and mixing the powder with a vanadium source precursor solution and a high molecular dispersing agent to form slurry, drying and roasting to form the denitration catalyst. The denitration catalyst prepared by the invention can overcome the defect of poor activity of the denitration catalyst in flue gas in the prior art. The invention also discloses a denitration catalyst.
Description
Technical Field
The invention belongs to the technical field of inorganic new materials, particularly relates to a denitration catalyst and a preparation method thereof, and particularly relates to a denitration catalyst which overcomes the defects of uneven dispersion of active components and unstable activity of the denitration catalyst in the prior art and a preparation method thereof.
Background
Nitrogen Oxides (NO) x ) Is one of the main atmospheric pollutants, and the emission requirements are increasingly strict. GB13223-2001, issued by the national environmental protection ministry in 9 months 2011, the emission standard of atmospheric pollutants of thermal power plants makes more strict requirements on the NOx emission concentration of the thermal power plants: 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/m 3 . The requirements of the emission standard of pollutants for petroleum refining industry issued by the national environmental protection department are as follows: the requirement of newly-built catalytic cracking unit for discharging nitrogen oxides in the regenerated flue gas is less than 200mg/m from 7 months to 1 day in 2015 3 Particular emission limits of less than 100mg/m 3 Existing enterprises of 7 months and 1 day in 2017 also perform the sameAnd (4) standard. Among the various flue gas denitration techniques, selective Catalytic Reduction (SCR) is still the mainstream technique in the world, and NO thereof x The 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 of different boiler types in the last 80 th century, and many scientific research units and enterprises in China also carried out a series of researches on the fuel boiler flue gas and refining flue gas conditions in China, and developed some denitration catalysts.
CN201010537130.0 proposes a method for preparing a denitration catalyst by using a hydrothermal method, which comprises the steps of firstly 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 simultaneously introducing elements such as vanadium, molybdenum and the like 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.
CN201110345605.0 provides a preparation method of a denitration catalyst, which comprises the steps of sequentially adding ammonium tungstate, ammonium molybdate and ammonium metavanadate into metatitanic acid slurry, carrying out 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 dispersed 2 /SO 3 The conversion rate is high, and the use performance of the catalyst is influenced.
In conclusion, the preparation of the denitration catalyst involves the mixing of various metal oxides, the difference of the mixing mode and the process has great influence on the denitration performance of the catalyst, and part of the formula NO x The conversion rate can reach more than 90 percent, but the high denitration rate can generate the problem of unstable activity and is difficult to deal with the rapid change of the components of the flue gas and the long-period stable operation. Therefore, the quality of the overall performance of the catalyst needs to be verified from other aspects of characterization, and the preparation of the catalyst is compatible with industrial scale-up operabilityAnd (5) performing sexual function.
Disclosure of Invention
The invention mainly aims to provide a preparation method of a denitration catalyst, which overcomes the defects of uneven dispersion of active components and unstable activity of the denitration catalyst in the prior art.
Therefore, the invention provides a preparation method of a denitration catalyst, which comprises the following steps:
(1) Dissolving a titanium source precursor in acid to form a titanium source precursor solution;
(2) Dissolving an aluminum source precursor to form a solution, and uniformly mixing the solution with a titanium source precursor solution to obtain a mixed solution;
(3) Adjusting the pH value of the mixed solution to 7-11, precipitating, filtering, washing and drying to form primary anatase crystal form powder;
(4) Mixing the primary anatase crystal form powder with a strong alkali solution to form slurry, precipitating, filtering and washing to obtain a filter cake;
(5) Adding deionized water into the filter cake to prepare slurry, adding the active component solution, uniformly mixing, drying, roasting, and grinding into powder; wherein the active component solution is a solution consisting of one or two of a tungsten source precursor and a molybdenum source precursor;
(6) And (4) mixing the powder obtained in the step (5), a vanadium source precursor solution and a high molecular dispersing agent to obtain slurry, drying and roasting to obtain the denitration catalyst.
In the preparation method of the denitration catalyst, the titanium source precursor is preferably titanyl sulfate or metatitanic acid, the acid is an inorganic acid, and the titanium content in the titanium source precursor solution is TiO 2 The weight is 15-40 g/L.
In the preparation method of the denitration catalyst, the aluminum source precursor is preferably aluminum sulfate, and the aluminum source precursor is preferably Al 2 O 3 And TiO 2 The mass ratio of aluminum to titanium in the mixed solution is 0.1 to 5.0.
According to the preparation method of the denitration catalyst, the tungsten source precursor is preferably ammonium paratungstate or ammonium metatungstate, the molybdenum source precursor is one or more of ammonium dimolybdate, ammonium trimolybdate, ammonium tetramolybdate, ammonium heptamolybdate or ammonium octamolybdate, and the mass ratio of tungsten to molybdenum in the active component solution is 1.0-10.0.
In the preparation method of the denitration catalyst, it is preferable that the vanadium source precursor in the vanadium source precursor solution is ammonium metavanadate, and V is used 2 O 5 And TiO 2 In terms of mass, the mass ratio of vanadium in the vanadium source precursor solution to titanium in the powder in step (5) is 0.1 to 5.0, more preferably 0.3 to 3.0.
In the preparation method of the denitration catalyst, the mixing time in the step (4) is preferably 1-24 hours, and the water content of the slurry in the steps (4), (5) and (6) is preferably 25-65 wt%.
In the method for preparing the denitration catalyst of the present invention, tiO is preferably used 2 And (3) the mass ratio of the addition amount of the polymer dispersant to the titanium in the powder in the step (5) is 0.1-2.0.
In the preparation method of the denitration catalyst, the polymer dispersant is preferably one or more selected from polyethylene glycol, polyacrylamide and polyethylene pyrrolidone. The macromolecular dispersing agent provided by the invention can uniformly disperse the active vanadium source precursor by utilizing the characteristics of the molecular structure of the macromolecular dispersing agent, and simultaneously, micropores are left on the catalyst substrate after roasting, so that the micropore structure of the catalyst is increased.
In the preparation method of the denitration catalyst of the present invention, it is preferable that in the step (5) and the step (6), the calcination conditions are both: the temperature is 350-620 ℃, and the time is 2-12 h.
Therefore, the invention also provides a denitration catalyst, which is prepared by the preparation method of the denitration catalyst.
The invention has the following beneficial effects:
(1) Mixing titanium atoms and aluminum atoms at a molecular level by using an in-situ mixing method, so that crystals with lattice defects are generated in a subsequent coprecipitation process, and the mixed metal oxide has small and uniform particle size;
(2) Aluminum atoms in the titanium-aluminum crystal lattice are dissolved out by using strong base, so that the crystal lattice defect of the titanium substrate is greatly increased, the crystal lattice defect of the aluminum dissolved out by using the strong base is a surface position which is easy to contact with flue gas in the flue gas atmosphere, and the SCR catalytic activity can be effectively exerted after the position supplement of the cocatalyst component, so that the denitration effect is improved under the same condition;
(3) And one or two of tungsten and molybdenum elements are added to the titanium substrate after the aluminum element is dissolved out, and because more lattice defects exist, the tungsten or molybdenum elements are added, so that the lattice defects of the roasted hybrid substrate are more stable, and the anatase type of the crystal form of the titanium substrate can be kept from being transformed during high-temperature roasting, thereby being more beneficial to keeping high denitration effect.
(4) Under the action of a macromolecular dispersant, a vanadium source is fully dispersed on a hybridized base material, and meanwhile, under the influence of a cocatalyst component tungsten or molybdenum on the base material with larger lattice defects, the vanadium source penetrates deeper on the surface of titanium-tungsten (molybdenum) particles, is connected more tightly, is dispersed more uniformly, and has higher and stable catalyst activity after roasting.
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.
The invention provides a preparation method of a denitration catalyst, which comprises the following steps:
(1) Dissolving a titanium source precursor in acid to form a titanium source precursor solution;
(2) Dissolving an aluminum source precursor to form a solution, and uniformly mixing the solution with a titanium source precursor solution to obtain a mixed solution;
(3) Adjusting the pH value of the mixed solution to 7-11, precipitating, filtering, washing and drying to form primary anatase crystal form powder;
(4) Mixing the primary anatase crystal form powder with a strong alkali solution to form slurry, precipitating, filtering and washing to obtain a filter cake;
(5) Adding deionized water into the filter cake to prepare slurry, adding the active component solution, uniformly mixing, drying, roasting, and grinding into powder; wherein the active component solution is a solution consisting of one or two of a tungsten source precursor and a molybdenum source precursor;
(6) And (4) mixing the powder obtained in the step (5), a vanadium source precursor solution and a high molecular dispersing agent to obtain slurry, drying and roasting to obtain the denitration catalyst.
In some embodiments, it is preferred that the titanium source precursor is titanyl sulfate or metatitanic acid, the acid is an inorganic acid, and the titanium content of the titanium source precursor solution is in the form of TiO 2 The weight is 15-40 g/L.
In some embodiments, it is preferred that the aluminum source precursor is aluminum sulfate, in the form of Al 2 O 3 And TiO 2 The mass ratio of aluminum to titanium in the mixed solution is 0.1 to 5.0.
In some embodiments, it is preferable that the tungsten source precursor is ammonium paratungstate or ammonium metatungstate, the molybdenum source precursor is one or more of ammonium dimolybdate, ammonium trimolybdate, ammonium tetramolybdate, ammonium heptamolybdate, or ammonium octamolybdate, and a mass ratio of tungsten to molybdenum in the active component solution is 1.0 to 10.0.
In some embodiments, it is preferable that the vanadium source precursor in the vanadium source precursor solution is ammonium metavanadate, and V is 2 O 5 And TiO 2 The mass ratio of vanadium in the vanadium source precursor solution to titanium in the powder in the step (5) is 0.1 to 5.0, more preferably 0.3 to 3.0.
In some embodiments, it is preferable that the mixing time in step (4) is 1 to 24 hours, and the water content of the slurry in step (4), step (5) and step (6) is 25 to 65wt%.
In some embodiments, it is preferred to use TiO 2 And (3) the mass ratio of the addition amount of the polymer dispersant to the titanium in the powder in the step (5) is 0.1-2.0.
In some embodiments, it is preferable that the polymeric dispersant is one or more selected from polyethylene glycol, polyacrylamide, and polyvinyl pyrrolidone. The macromolecular dispersing agent provided by the invention can uniformly disperse the active vanadium source precursor by utilizing the characteristics of the molecular structure of the macromolecular dispersing agent, and simultaneously, micropores are left on the catalyst substrate after roasting, so that the micropore structure of the catalyst is increased.
In some embodiments, it is preferable that in step (5) and step (6), the firing conditions are both: the temperature is 350-620 ℃, and the time is 2-12 h.
The denitration catalyst provided by the invention is prepared by the preparation method of the denitration catalyst.
The following examples
Preparation of a catalyst sample: the prepared fresh catalyst is crushed and sieved to obtain 20-40 mesh powder for evaluation.
The mixed treatment process of the catalyst sample and the flue dust comprises the following steps: preparing a fresh catalyst sample; screening the flue dust, and taking 40-60 meshes of powder, wherein the dust contains impurities such as vanadium oxide, nickel oxide, alkali and alkaline earth metal oxide and the like. The two kinds of powders were mixed in a mass ratio of 1:1, mixed at 420 ℃ for 72 hours in an air atmosphere, and then the catalyst powder was sieved out for evaluation. In the process of contacting and mixing the fresh catalyst and the flue dust, harmful substances in the dust are unevenly transferred to the fresh catalyst, SO that the surface activity and the selectivity of the fresh catalyst are reduced, and the SO of the catalyst is increased 2 /SO 3 The conversion rate and the overall performance of the denitration catalyst are reduced.
NO x Conversion evaluation conditions: airspeed of 30000h -1 Reaction temperature 300 ℃ and inlet gas NO x 600mg/Nm 3 、SO 2 600mg/Nm 3 The ammonia-nitrogen ratio is 1, and the water content is 8%.
NO x 、SO 2 The concentration measuring method comprises the following steps: smoke continuous on-line analyzer, siemens ULTRAMAT23.
SO 2 /SO 3 The conversion rate determination method comprises the following steps: limestone-gypsum wet flue gas desulfurization device performance acceptance test specification (DL/T99)8-2006)。
The following examples are specific illustrations of the present invention, and "%" described in examples and comparative examples means mass percent.
Example 1:
will be made of TiO 2 Dissolving 100g of titanyl sulfate in 200ml of 2mol/L sulfuric acid to form a solution; will be mixed with Al 2 O 3 A total of 4g of aluminum sulfate was dissolved in 20ml of deionized water to prepare a solution. Uniformly mixing the two solutions, adjusting the pH value to 10 by using ammonia water, completely precipitating, filtering, washing and drying; putting the dried material into 5mol/L sodium hydroxide solution, stirring and mixing for 12h, precipitating, filtering and washing to obtain a filter cake; preparing the filter cake into slurry with water content of 40% by using deionized water, and adding WO 3 Metering 5g of ammonium metatungstate solution, stirring for 2 hours, drying, roasting at 550 ℃ for 4 hours, and grinding into powder; mixing the calcined powder with V 2 O 5 Preparing slurry containing 30% of water by counting 1.0g of ammonium metatungsten vanadate solution, adding 0.8g of polyvinylpyrrolidone after stirring, stirring for 90min, sealing and standing for 24h, drying, and roasting at 600 ℃ for 8h to obtain the denitration catalyst.
The obtained fresh catalyst and the catalyst mixed with dust in catalytic cracking regeneration flue gas at high temperature are respectively evaluated. Evaluation results were as follows: fresh catalyst NO x Conversion rate is 97.8%, and catalyst NO is obtained after mixing treatment x The conversion was 97.7%.
Comparative example 1:
will contain TiO 2 Dissolving 100g of titanyl sulfate in 200ml of 2mol/L sulfuric acid to form a solution, adjusting the pH value to 10 by using ammonia water, and filtering, washing and drying after complete precipitation; putting the dried material into 5mol/L sodium hydroxide solution, stirring for 12h, precipitating, filtering and washing to obtain a filter cake; preparing the filter cake into slurry with the water content of 40% by using deionized water, and adding WO 3 5g of ammonium metatungstate solution is counted, stirred for 2 hours, dried, roasted for 4 hours at the temperature of 550 ℃, and ground into powder; mixing the calcined powder with V 2 O 5 Preparing slurry containing 30% water from 1.0g ammonium metavanadate solution, stirring, adding 0.8g polyvinylpyrrolidone, stirring for 90min, sealing, standing for 24 hr, oven drying, and roasting at 600 deg.C for 8And h, obtaining the denitration catalyst.
In contrast to example 1, no aluminum element was involved in the preparation of the catalyst.
The obtained fresh catalyst and the catalyst mixed with dust in catalytic cracking regeneration flue gas at high temperature are respectively evaluated. Evaluation results were as follows: fresh catalyst NO x Conversion rate of 91.6%, mixed treated catalyst NO x The conversion was 89.4%.
Example 2
Will be made of TiO 2 Dissolving 100g of titanyl sulfate in 200ml of 2mol/L sulfuric acid to form a solution; will be mixed with Al 2 O 3 A total of 3g of aluminum sulfate was dissolved in 20ml of deionized water to prepare a solution. Uniformly mixing the two solutions, adjusting the pH value to 9.5 by using ammonia water, completely precipitating, filtering, washing and drying; putting the dried material into a 4mol/L sodium hydroxide solution, stirring for 12 hours, precipitating, filtering and washing to obtain a filter cake; preparing the filter cake into slurry with the water content of 35% by using deionized water, and adding WO 3 Weighing 4g of ammonium metatungstate solution, stirring for 2 hours, drying, roasting at 550 ℃ for 4 hours, and grinding into powder; the powder after roasting is mixed with V 2 O 5 0.9g of ammonium metavanadate solution is prepared into slurry with the water content of 30 percent, 1.0g of polyethylene glycol is added after stirring, the mixture is stirred for 100min, sealed and kept stand for 24h, dried and roasted at 600 ℃ for 8h to obtain the denitration catalyst.
The fresh catalyst obtained above and the catalyst after being mixed with colloid dust in the flue gas of the ethylene cracking furnace at high temperature are respectively evaluated. Evaluation results were as follows: fresh catalyst NO x Conversion rate of 96.3%, mixed treated catalyst NO x The conversion was 96.1%.
Comparative example 2
Will contain TiO 2 Dissolving 100g of titanyl sulfate in 200ml of 2mol/L sulfuric acid to form a solution; will contain Al 2 O 3 A3 g portion of aluminum sulfate was dissolved in deionized water to form a solution. Uniformly mixing the two solutions, adjusting the pH value to 9.5 by using ammonia water, completely precipitating, filtering, washing and drying; putting the dried material into a 4mol/L sodium hydroxide solution, stirring for 12 hours, precipitating, filtering and washing to obtain a filter cake; deionized water is used for filter cakePreparing into slurry with water content of 35%, adding WO 3 Weighing 4g of ammonium metatungstate solution, stirring for 2 hours, drying, roasting at 550 ℃ for 4 hours, and grinding into powder; mixing the calcined powder with V 2 O 5 0.9g of ammonium metavanadate solution is prepared into slurry with the water content of 30 percent, the slurry is stirred for 100min, sealed and kept stand for 24h, dried and roasted at 600 ℃ for 8h to obtain the denitration catalyst.
In contrast to example 2, no polymeric dispersant was involved in the catalyst preparation step.
The fresh catalyst and the catalyst mixed with colloid dust in the flue gas of the ethylene cracking furnace at high temperature are respectively evaluated. Evaluation results were as follows: fresh catalyst NO x Conversion rate of 92.5 percent and catalyst NO after mixed treatment x The conversion was 91.0%.
Example 3
Will contain TiO 2 Dissolving 100g of titanyl sulfate in 200ml of 2mol/L sulfuric acid to form a solution; will contain Al 2 O 3 2g of aluminum sulfate was dissolved in 20ml of deionized water to prepare a solution. Uniformly mixing the two solutions, adjusting the pH value to 9 by using ammonia water, and filtering, washing and drying after complete precipitation; putting the dried material into 3mol/L sodium hydroxide solution, stirring for 10h, precipitating, filtering, washing to obtain a filter cake; preparing the filter cake into slurry with the water content of 30% by using deionized water, and adding WO 3 Weighing 7g of ammonium metatungstate solution, stirring for 2 hours, drying, roasting at 550 ℃ for 4 hours, and grinding into powder; mixing the calcined powder with V 2 O 5 Preparing 1.2g of ammonium metavanadate solution into slurry containing 40% of water, stirring, adding 1.0g of polyacrylamide, stirring for 100min, sealing and standing for 24h, drying, and roasting at 600 ℃ for 8h to obtain the denitration catalyst.
The fresh catalyst obtained above was evaluated. Evaluation results were as follows: fresh catalyst NO x The conversion was 96.8%.
Comparative example 3
Will contain TiO 2 Dissolving 100g of titanyl sulfate in 200ml of 2mol/L sulfuric acid to form a solution; will contain Al 2 O 3 A total of 2g of aluminum sulfate was dissolved in deionized water to form a solution. Mixing the above two solutions, and adding ammoniaAdjusting the pH value to 9 with water, filtering, washing and drying after complete precipitation; preparing the dried material into slurry with the water content of 30% by using deionized water, and adding WO 3 Weighing 7g of ammonium metatungstate solution, stirring for 2 hours, drying, roasting at 550 ℃ for 4 hours, and grinding into powder; mixing the calcined powder with V 2 O 5 Preparing 1.2g of ammonium metavanadate solution into slurry containing 40% of water, stirring, adding 1.0g of polyacrylamide, stirring for 100min, sealing and standing for 24h, drying, and roasting at 600 ℃ for 8h to obtain the denitration catalyst.
Compared with the example 3, the preparation step of the catalyst does not adopt a process step of leaching the aluminum element by alkali.
The fresh catalyst obtained above was evaluated. Evaluation results were as follows: fresh catalyst NO x The conversion was 93.5%.
Example 4
Will contain TiO 2 Dissolving 100g of titanyl sulfate in 200ml of 2mol/L sulfuric acid to form a solution; will contain Al 2 O 3 A total of 4.5g of aluminum sulfate was dissolved in 20ml of deionized water to prepare a solution. Uniformly mixing the two solutions, adjusting the pH value to 10 by using ammonia water, and filtering, washing and drying after complete precipitation; putting the dried material into a 4mol/L sodium hydroxide solution, stirring for 12 hours, precipitating, filtering and washing to obtain a filter cake; preparing the filter cake into slurry with the water content of 40% by using deionized water, and adding WO 3 Weighing 4g of ammonium metatungstate solution, stirring for 2 hours, drying, roasting at 550 ℃ for 4 hours, and grinding into powder; mixing the calcined powder with V 2 O 5 Preparing slurry containing 30% of water by counting 1.8g of ammonium metavanadate solution, adding 1.2g of polyvinylpyrrolidone after stirring, stirring for 90min, sealing and standing for 24h, drying, and roasting at 600 ℃ for 8h to obtain the denitration catalyst.
The obtained fresh catalyst and the catalyst mixed with the dust in the flue gas of the coal-fired boiler at high temperature are respectively evaluated. Evaluation results were as follows: fresh catalyst NO x Conversion rate of 98.4%, mixed treated catalyst NO x The conversion was 98.2%.
Comparative example 4
Will contain TiO 2 100g of titanyl sulfate was dissolved in 200ml of 2mol/L sulfurForming a solution with an acid; will contain Al 2 O 3 A total of 4.5g of aluminum sulfate was dissolved in 20ml of deionized water to prepare a solution. Uniformly mixing the two solutions, adjusting the pH value to 10 by using ammonia water, completely precipitating, filtering, washing and drying; putting the dried material into a 4mol/L sodium hydroxide solution, stirring for 12 hours, precipitating, filtering and washing to obtain a filter cake; preparing the filter cake into slurry with the water content of 40% by using deionized water, and adding WO 3 Weighing 4g of ammonium metatungstate solution, stirring for 2 hours, drying, roasting at 550 ℃ for 4 hours, and grinding into powder; mixing the calcined powder with V 2 O 5 Preparing slurry containing 30% of water by counting 1.8g of ammonium metavanadate solution, adding 1.2g of polyvinylpyrrolidone after stirring, stirring for 90min, sealing and standing for 24h, drying, and roasting at 600 ℃ for 8h to obtain the denitration catalyst.
In contrast to example 4, the catalyst preparation procedure was carried out without the addition of polyvinylpyrrolidone.
The fresh catalyst and the catalyst mixed with the dust in the flue gas of the coal-fired boiler at high temperature are respectively evaluated. Evaluation results were as follows: fresh catalyst NO x Conversion rate of 93.8%, mixed treated catalyst NO x The conversion was 92.5%.
Example 5
Will contain TiO 2 Dissolving 100g of titanyl sulfate in 200ml of 2mol/L sulfuric acid to form a solution; will contain Al 2 O 3 A total of 5.0g of aluminum sulfate was dissolved in 20ml of deionized water to prepare a solution. Uniformly mixing the two solutions, adjusting the pH value to 10 by using ammonia water, completely precipitating, filtering, washing and drying; putting the dried material into a 4.5mol/L sodium hydroxide solution, stirring for 10h, precipitating, filtering and washing to obtain a filter cake; preparing the filter cake into slurry with the water content of 40% by using deionized water, and adding MoO 3 5g of ammonium molybdate solution is counted, stirred for 3 hours and then dried, roasted for 4 hours at 550 ℃, and ground into powder; mixing the calcined powder with V 2 O 5 Preparing 1.2g of ammonium metavanadate solution into slurry with the water content of 30%, stirring, adding 1.0g of polyvinylpyrrolidone, stirring for 90min, sealing and standing for 24h, drying, and roasting at 600 ℃ for 8h to obtain the denitration catalyst.
The obtained fresh catalyst and the catalyst mixed with the dust in the flue gas of the coal-fired boiler at high temperature are respectively evaluated. Evaluation results were as follows: fresh catalyst NO x Conversion rate is 97.9%, and catalyst NO is obtained after mixing treatment x The conversion was 97.7%.
Comparative example 5
Will contain TiO 2 Dissolving 100g of titanyl sulfate in 200ml of 2mol/L sulfuric acid to form a solution; will contain Al 2 O 3 Aluminum sulfate (5.0 g) was dissolved in 20ml of deionized water to prepare a solution. Uniformly mixing the two solutions, adjusting the pH value to 10 by using ammonia water, and filtering, washing and drying after complete precipitation; putting the dried material into a 4.5mol/L sodium hydroxide solution, stirring for 10 hours, fully washing and filtering; roasting at 550 ℃ for 4h, and grinding into powder; the powder after roasting is mixed with V 2 O 5 Preparing 1.2g of ammonium metavanadate solution into slurry with the water content of 30%, stirring, adding 1.0g of polyvinylpyrrolidone, stirring for 90min, sealing and standing for 24h, drying, and roasting at 600 ℃ for 8h to obtain the denitration catalyst.
In contrast to example 5, the catalyst was prepared without the addition of an appropriate amount of ammonium molybdate solution.
The obtained fresh catalyst and the catalyst mixed with the dust in the flue gas of the coal-fired boiler at high temperature are respectively evaluated. Evaluation results were as follows: fresh catalyst NO x Conversion rate 86.3%, mixed treated catalyst NO x The conversion was 83.1%.
Example 6
Will contain TiO 2 Dissolving 100g of titanyl sulfate in 200ml of 2mol/L sulfuric acid to form a solution; will contain Al 2 O 3 Aluminum sulfate (1.0 g) was dissolved in 20ml of deionized water to prepare a solution. Uniformly mixing the two solutions, adjusting the pH value to 10 by using ammonia water, completely precipitating, filtering, washing and drying; putting the dried material into 2mol/L sodium hydroxide solution, stirring for 10h, precipitating, filtering, washing to obtain a filter cake; preparing the filter cake into slurry with the water content of 35% by using deionized water, and adding MoO 3 Metering 3.5g of ammonium molybdate solution, stirring for 3h, drying, roasting at 550 ℃ for 4h, and grinding into powder; mixing the calcined powder with V 2 O 5 0.6g of ammonium metavanadate solution is prepared into slurry with the water content of 30%, 0.8g of polyvinylpyrrolidone is added after stirring, the mixture is stirred for 90min, sealed and kept stand for 24h, dried and roasted at 600 ℃ for 8h to obtain the denitration catalyst.
The obtained fresh catalyst and the catalyst mixed with the dust in the flue gas of the coal-fired boiler at high temperature are respectively evaluated. Evaluation results were as follows: fresh catalyst NO x Conversion rate of 96.3%, mixed treated catalyst NO x The conversion was 96.0%.
Comparative example 6
Will contain TiO 2 Dissolving 100g of titanyl sulfate in 200ml of 2mol/L sulfuric acid to form a solution; will contain Al 2 O 3 Aluminum sulfate (1.0 g) was dissolved in 20ml of deionized water to prepare a solution. Uniformly mixing the two solutions, adjusting the pH value to 10 by using ammonia water, completely precipitating, filtering, washing and drying; putting the dried material into 2mol/L sodium hydroxide solution, stirring for 10h, precipitating, filtering, washing to obtain a filter cake; preparing the filter cake into slurry with the water content of 35% by using deionized water, and adding MoO 3 Metering 3.5g of ammonium molybdate solution, stirring for 3h, drying, roasting at 550 ℃ for 4h, and grinding into powder; mixing the calcined powder with V 2 O 5 0.6g of ammonium metavanadate solution is prepared into slurry with the water content of 30 percent, the slurry is stirred for 90min, sealed and kept stand for 24h, dried and roasted at 600 ℃ for 8h to obtain the denitration catalyst.
In contrast to example 6, the catalyst preparation procedure was carried out without the addition of polyvinylpyrrolidone.
The obtained fresh catalyst and the catalyst mixed with the dust in the flue gas of the coal-fired boiler at high temperature are respectively evaluated. Evaluation results were as follows: fresh catalyst NO x Conversion rate of 92.8 percent and catalyst NO after mixed treatment x The conversion was 91.3%.
Example 7
Will contain TiO 2 Dissolving 100g of titanyl sulfate in 200ml of 2mol/L sulfuric acid to form a solution; will contain Al 2 O 3 A total of 5g of aluminum sulfate was dissolved in 20ml of deionized water to form a solution. Mixing the above two solutions, adjusting pH to 9 with ammonia water, precipitating completely, filtering,Washing and drying; putting the dried material into a 4.5mol/L sodium hydroxide solution, stirring for 10h, precipitating, filtering and washing to obtain a filter cake; preparing the filter cake into slurry with the water content of 35% by using deionized water, and adding WO 3 Metering 10g of ammonium metatungstate solution, stirring for 2 hours, drying, roasting at 550 ℃ for 4 hours, and grinding into powder; mixing the calcined powder with V 2 O 5 Preparing 1.0g of ammonium metavanadate solution into slurry containing 40% of water, stirring, adding 1.1g of polyacrylamide, stirring for 100min, sealing and standing for 24h, drying, and roasting at 610 ℃ for 8h to obtain the denitration catalyst.
The fresh catalyst obtained above was evaluated. Evaluation results were as follows: fresh catalyst NO x The conversion was 95.9%.
Comparative example 7
Will contain TiO 2 Dissolving 100g of titanyl sulfate in 200ml of 2mol/L sulfuric acid to form a solution; adjusting the pH value to 9 by using ammonia water, filtering, washing and drying after complete precipitation; preparing the dried material into slurry with the water content of 35% by using deionized water, and adding WO 3 Measuring 10g of ammonium metatungstate solution, stirring for 2h, drying, roasting at 550 ℃ for 4h, and grinding into powder; mixing the calcined powder with V 2 O 5 Preparing slurry containing 40% of water by metering 1.0g of ammonium metavanadate solution, adding 1.1g of polyacrylamide after stirring, stirring for 100min, sealing and standing for 24h, drying, and roasting at 610 ℃ for 8h to obtain the denitration catalyst.
In contrast to example 7, the catalyst was prepared without the use of a basic leaching of the aluminum element.
The fresh catalyst obtained above was evaluated. Evaluation results were as follows: fresh catalyst NO x The conversion was 92.2%.
Through the examples and comparative examples, it was found that: the denitration catalyst of the embodiment has good denitration effect, the titanium substrate and the aluminum element form an excellent mixed substrate material through primary in-situ mixing, the aluminum element is leached out through an alkali fusion process, and then the cocatalyst component is supplemented to enter the substrate, so that the high-temperature crystal form stability of the catalyst substrate and the lattice distortion of the substrate can be increased, and meanwhile, the uniform dispersion of the main active material vanadium species can be promoted to enter the substrateThereby improving the denitration activity of the catalyst. Under the action of a polymer dispersant, vanadium oxide is introduced to the prepared titanium-tungsten (molybdenum) substrate, and the denitration catalyst is obtained after roasting. NO in catalyst evaluation x The conversion rate of (A) is that the ammonia-nitrogen ratio is 1 and the space velocity is 30000h -1 When the denitration catalyst is used, the denitration rate can reach over 96 percent, and good denitration performance is shown; after the catalyst is mixed with actual flue dust, the activity of the catalyst is only slightly reduced, which indicates that the catalyst has excellent performance; in the preparation method of the denitration catalyst, if the denitration catalyst is not subjected to the treatment in the step (3), the leaching of aluminum element is not carried out, the denitration activity of a roasted catalyst sample is poor, and the denitration activity is reduced more after the denitration catalyst is mixed with flue dust; if the high molecular dispersing agent is not added in the treatment in the step (6), the denitration activity of the roasted catalyst sample is also crossed, and the denitration activity is also reduced to a certain extent after the catalyst sample is mixed with flue dust. In a word, when the fresh denitration catalyst and the treated catalyst prepared by the method are evaluated under the same condition, the denitration activity is lower than that of other comparative samples, and the catalyst has good catalytic activity.
In conclusion, the beneficial effects of the invention are as follows:
(1) Mixing titanium atoms and aluminum atoms at a molecular level by using an in-situ mixing method, so that crystals with lattice defects are generated in a subsequent coprecipitation process, and the mixed metal oxide has small and uniform particle size;
(2) Aluminum atoms in the titanium-aluminum crystal lattice are dissolved out by using strong base, so that the crystal lattice defect of the titanium substrate is greatly increased, the crystal lattice defect of the aluminum dissolved out by using the strong base is a surface position which is easy to contact with flue gas in the flue gas atmosphere, and the SCR catalytic activity can be effectively exerted after the position supplement of the cocatalyst component, so that the denitration effect is improved under the same condition;
(3) And one or two of tungsten and molybdenum elements are added to the titanium substrate after the aluminum element is dissolved out, and because more lattice defects exist, the tungsten or molybdenum elements are added, so that the lattice defects of the roasted hybrid substrate are more stable, and the anatase type of the crystal form of the titanium substrate can be kept from being transformed during high-temperature roasting, thereby being more beneficial to keeping high denitration effect.
(4) Under the action of a macromolecular dispersant, a vanadium source is fully dispersed on a hybridized base material, and meanwhile, under the influence of a cocatalyst component tungsten or molybdenum on the base material with larger lattice defects, the vanadium source penetrates deeper on the surface of titanium-tungsten (molybdenum) particles, is connected more tightly, is dispersed more uniformly, and has higher and stable catalyst activity after roasting.
The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and it is therefore intended that all such changes and modifications as fall within the true spirit and scope of the invention be considered as within the following claims.
Claims (10)
1. A preparation method of a denitration catalyst is characterized by comprising the following steps:
(1) Dissolving a titanium source precursor in acid to form a titanium source precursor solution;
(2) Dissolving an aluminum source precursor to form a solution, and uniformly mixing the solution with a titanium source precursor solution to obtain a mixed solution;
(3) Adjusting the pH value of the mixed solution to 7-11, precipitating, filtering, washing and drying to form primary anatase crystal form powder;
(4) Mixing the primary anatase crystal form powder and a strong base solution to form slurry, precipitating, filtering and washing to obtain a filter cake;
(5) Adding deionized water into the filter cake to prepare slurry, adding the active component solution, uniformly mixing, drying, roasting, and grinding into powder; wherein the active component solution is a solution consisting of one or two of a tungsten source precursor and a molybdenum source precursor;
(6) And (4) mixing the powder obtained in the step (5), a vanadium source precursor solution and a high molecular dispersing agent to obtain slurry, drying and roasting to obtain the denitration catalyst.
2. The method for preparing a denitration catalyst according to claim 1, wherein the titanium source precursor is titanyl sulfate or metatitanic acid, the acid is an inorganic acid, and the titanium content in the titanium source precursor solution is TiO 2 The weight is 15-40 g/L.
3. The method of claim 1, wherein the aluminum source precursor is aluminum sulfate, and the aluminum source precursor is Al 2 O 3 And TiO 2 The mass ratio of aluminum to titanium in the mixed solution is 0.1-5.0.
4. The method for preparing a denitration catalyst according to claim 1, wherein the tungsten source precursor is ammonium paratungstate or ammonium metatungstate, the molybdenum source precursor is one or more of ammonium dimolybdate, ammonium trimolybdate, ammonium tetramolybdate, ammonium heptamolybdate or ammonium octamolybdate, and the mass ratio of tungsten to molybdenum in the active component solution is 1.0-10.0.
5. The method for preparing a denitration catalyst according to claim 1, wherein the vanadium source precursor in the vanadium source precursor solution is ammonium metavanadate, and V is the amount of V 2 O 5 And TiO 2 The mass ratio of vanadium in the vanadium source precursor solution to titanium in the powder in the step (5) is 0.1-5.0, preferably 0.3-3.0.
6. The method for preparing a denitration catalyst according to claim 1, wherein the mixing time in the step (4) is 1 to 24 hours, and the water content of the slurry in the steps (4), (5) and (6) is 25 to 65wt%.
7. The method of claim 1, wherein the denitration catalyst is TiO 2 And (3) the mass ratio of the addition amount of the polymer dispersant to the titanium in the powder in the step (5) is 0.1-2.0.
8. The method for preparing a denitration catalyst according to claim 1, wherein the polymeric dispersant is one or more selected from polyethylene glycol, polyacrylamide, and polyethylene pyrrolidone.
9. The method of producing a denitration catalyst according to claim 1, wherein in the step (5) and the step (6), the conditions of the calcination are: the temperature is 350-620 ℃, and the time is 2-12 h.
10. A denitration catalyst produced by the method for producing a denitration catalyst according to any one of claims 1 to 9.
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| CN115555002B (en) | 2023-11-28 |
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