CN115739174A - Anti-hydrothermal-stability denitration catalyst, preparation method and application thereof, monolithic catalyst and application thereof - Google Patents
Anti-hydrothermal-stability denitration catalyst, preparation method and application thereof, monolithic catalyst and application thereof Download PDFInfo
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- JSKIRARMQDRGJZ-UHFFFAOYSA-N dimagnesium dioxido-bis[(1-oxido-3-oxo-2,4,6,8,9-pentaoxa-1,3-disila-5,7-dialuminabicyclo[3.3.1]nonan-7-yl)oxy]silane Chemical compound [Mg++].[Mg++].[O-][Si]([O-])(O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2)O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2 JSKIRARMQDRGJZ-UHFFFAOYSA-N 0.000 claims description 29
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- NGDQQLAVJWUYSF-UHFFFAOYSA-N 4-methyl-2-phenyl-1,3-thiazole-5-sulfonyl chloride Chemical group S1C(S(Cl)(=O)=O)=C(C)N=C1C1=CC=CC=C1 NGDQQLAVJWUYSF-UHFFFAOYSA-N 0.000 description 9
- XTVVROIMIGLXTD-UHFFFAOYSA-N copper(II) nitrate Chemical compound [Cu+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O XTVVROIMIGLXTD-UHFFFAOYSA-N 0.000 description 9
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- 239000012495 reaction gas Substances 0.000 description 6
- OPQARKPSCNTWTJ-UHFFFAOYSA-L copper(ii) acetate Chemical compound [Cu+2].CC([O-])=O.CC([O-])=O OPQARKPSCNTWTJ-UHFFFAOYSA-L 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 238000010531 catalytic reduction reaction Methods 0.000 description 4
- HSJPMRKMPBAUAU-UHFFFAOYSA-N cerium(3+);trinitrate Chemical group [Ce+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O HSJPMRKMPBAUAU-UHFFFAOYSA-N 0.000 description 4
- 239000007789 gas Substances 0.000 description 4
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- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 3
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- IHCCLXNEEPMSIO-UHFFFAOYSA-N 2-[4-[2-(2,3-dihydro-1H-inden-2-ylamino)pyrimidin-5-yl]piperidin-1-yl]-1-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)ethanone Chemical compound C1C(CC2=CC=CC=C12)NC1=NC=C(C=N1)C1CCN(CC1)CC(=O)N1CC2=C(CC1)NN=N2 IHCCLXNEEPMSIO-UHFFFAOYSA-N 0.000 description 2
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- FYDKNKUEBJQCCN-UHFFFAOYSA-N lanthanum(3+);trinitrate Chemical group [La+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O FYDKNKUEBJQCCN-UHFFFAOYSA-N 0.000 description 2
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- 238000011109 contamination Methods 0.000 description 1
- 229910000365 copper sulfate Inorganic materials 0.000 description 1
- ARUVKPQLZAKDPS-UHFFFAOYSA-L copper(II) sulfate Chemical compound [Cu+2].[O-][S+2]([O-])([O-])[O-] ARUVKPQLZAKDPS-UHFFFAOYSA-L 0.000 description 1
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Abstract
The invention provides a hydrothermal stability resistant denitration catalyst, a preparation method and application thereof, an integral catalyst and application thereof, and belongs to the technical field of hydrothermal stability resistant denitration catalysts. The invention provides a preparation method of a hydrothermal stability resistant denitration catalyst, which comprises the following steps: mixing the SAPO-34 molecular sieve with a rare earth metal salt water solution, and carrying out ion exchange reaction to obtain rare earth modified SAPO-34; subjecting the rare earth to a reactionMixing the modified SAPO-34 with a copper precursor salt solution, and then roasting to obtain rare earth modified Cu-SAPO-34; and carrying out hydrothermal aging on the rare earth modified Cu-SAPO-34 in a water vapor-air mixed atmosphere to obtain the hydrothermal stability resistant denitration catalyst. The catalyst provided by the invention has rich pore structure and strong acidity; has excellent low-temperature catalytic activity, wider active temperature window, good hydrothermal aging resistance and N 2 And (4) selectivity.
Description
Technical Field
The invention relates to the technical field of denitration catalysts, and particularly relates to a hydrothermal-resistant stable denitration catalyst, a preparation method and application thereof, and an integral catalyst and application thereof.
Background
Nitrogen Oxides (NO) x ) Is one of the main pollutants of the atmosphere, can cause environmental problems such as acid rain, photochemical smog, ozone layer damage and the like, and also can harm human health. With NO x Increasingly stringent emission standards for NO x The purification and pollution control of the method are imperative.
Selective catalytic reduction of NO with ammonia x (NH 3 SCR technology) with high denitration efficiency and N 2 Selective, effective reduction of NO x A method of contamination. Currently used industrial NH 3 -the SCR catalyst comprises V 2 O 5 -WO 3 -TiO 2 And V 2 O 5 -MoO 3 -TiO 2 . However, the catalyst has poor low-temperature activity, narrow active temperature window and poor high-temperature stability, contains vanadium compounds and has high toxicity to human bodies and animals. The Cu-SAPO-34 molecular sieve catalyst has N 2 High selectivity, good thermal stability, etc., and is considered to be the optimum NH 3 -denitration catalyst by SCR technology. Chinese patent CN104307564A discloses a preparation method of an auxiliary agent doped Cu-SAPO-34 catalyst, which adopts a liquid ion exchange method to prepare the Cu-SAPO-34 catalyst, then adopts an isometric impregnation method to dope the auxiliary agent, and then calcinates the auxiliary agent doped Cu-SAPO-34 catalyst in an air atmosphere. However, the adjuvant-doped Cu-SAPO-34 catalyst prepared by the above method is used for selective catalytic reduction of NO x When is NO x The temperature range of the conversion rate higher than 90 percent is 200 to 450 ℃, and the active temperature window isAnd (4) narrow.
Disclosure of Invention
In view of the above, the invention aims to provide a hydrothermal stability resistant denitration catalyst, a preparation method and an application thereof, and an integral catalyst and an application thereof 2 The selectivity is high.
In order to achieve the above object, the present invention provides the following technical solutions:
the invention provides a preparation method of a hydrothermal stability resistant denitration catalyst, which comprises the following steps:
removing non-framework aluminum from the SAPO-34 molecular sieve by using a dilute phosphoric acid solution to obtain a non-framework aluminum removed SAPO-34 molecular sieve;
mixing the non-framework aluminum removed SAPO-34 molecular sieve with a rare earth metal saline solution, and carrying out ion exchange reaction to obtain rare earth modified SAPO-34;
placing the rare earth modified SAPO-34 into a mixed solution of copper precursor salt and ammonia water for dipping and then roasting to obtain rare earth modified Cu-SAPO-34;
and carrying out hydrothermal aging on the rare earth modified Cu-SAPO-34 in a water vapor-air mixed atmosphere to obtain the hydrothermal stability resistant denitration catalyst.
Preferably, the concentration of the dilute phosphoric acid solution is 0.01-1 mol/L, the temperature of the non-framework aluminum removal treatment is 30-60 ℃, and the time is 20-120 min.
Preferably, the rare earth metal salt in the rare earth metal salt aqueous solution comprises one or more of water-soluble cerium salt, water-soluble lanthanum salt and water-soluble yttrium salt; the concentration of the rare earth metal salt aqueous solution is 0.01-1 mol/L.
Preferably, the temperature of the ion exchange reaction is 80-120 ℃ and the time is 4-12 h.
Preferably, the mass ratio of copper in the rare earth modified SAPO-34 molecular sieve to copper precursor salt is 93-99;
the concentration of the ammonia water is 0.01-0.5 mol/L.
Preferably, the dipping temperature is 30-80 ℃, and the time is 2-8 h;
the roasting temperature is 500-700 ℃, and the roasting time is 2-6 h.
Preferably, the volume fraction of the water vapor in the water vapor-air mixed atmosphere is 4-12%;
the temperature of the hydrothermal aging is 600-800 ℃, and the time is 3-15 h.
The invention provides a hydrothermal stability resistant denitration catalyst prepared by the preparation method of the technical scheme.
The invention provides a monolithic catalyst, which comprises cordierite and a catalytic component coated on the surface of the cordierite; the catalytic component comprises the denitration catalyst with hydrothermal stability.
The invention also provides the application of the anti-hydrothermal stability denitration catalyst or the monolithic catalyst in the technical scheme in selective reduction of nitrogen oxides.
The invention provides a preparation method of a hydrothermal stability resistant denitration catalyst, which comprises the following steps: removing non-framework aluminum from the SAPO-34 molecular sieve by using a dilute phosphoric acid solution to obtain a non-framework aluminum removed SAPO-34 molecular sieve; mixing the non-framework aluminum removed SAPO-34 molecular sieve with a rare earth metal saline solution, and carrying out ion exchange reaction to obtain rare earth modified SAPO-34; placing the rare earth modified SAPO-34 into a mixed solution of copper precursor salt and ammonia water for dipping and then roasting to obtain rare earth modified Cu-SAPO-34; and carrying out hydrothermal aging on the rare earth modified Cu-SAPO-34 in a water vapor-air mixed atmosphere to obtain the hydrothermal stability resistant denitration catalyst. In the invention, the SAPO-34 molecular sieve has rich microporous structure, and is favorable for preventing by-product N in the selective reduction process of nitrogen oxide 2 Generation of O; the rare earth metal ions replace part of NH in the SAPO-34 molecular sieve by ion exchange reaction 4 + The framework Al in the SAPO-34 molecular sieve can be stabilized; in the course of calcination, cu 2+ Form substituted NH in rare earth modified SAPO-34 molecular sieve 4 + Or a copper precursorThe salt forms CuO particles in or outside the pore canal of the rare earth modified SAPO-34 molecular sieve, so that an active center can be provided; hydrothermal aging is carried out in the mixed atmosphere of water vapor and air, and rare earth metal ions not only can stabilize SAPO-34 molecular sieve framework Al, but also can inhibit the preparation of substitutional Cu 2+ Migration and aggregation occur, so the rare earth metal ions play a good stabilizing role on the framework of the SAPO-34 molecular sieve, thereby improving the hydrothermal resistance stability of the catalyst. Moreover, the preparation method provided by the invention has the advantages of simple process and low preparation cost, and is suitable for industrial production.
The invention provides a hydrothermal stability resistant denitration catalyst prepared by the preparation method of the technical scheme. The catalyst provided by the invention has rich pore structures and strong acidity; has excellent low-temperature catalytic activity, wider active temperature window, good hydrothermal aging resistance and N 2 And (4) selectivity.
The invention provides a monolithic catalyst, which comprises cordierite and a catalytic component coated on the surface of the cordierite; the catalytic component comprises the anti-hydrothermal stable denitration catalyst. In the invention, the cordierite can make the reaction gas fully contact with the active component, and the denitration efficiency and the hydrothermal resistance stability of the catalyst are improved. As shown by the results of the examples, the monolithic catalyst selectively catalyzes the reduction of NO x ，NO x The temperature range of the conversion rate of more than or equal to 90 percent is 140 to 480 ℃, and the conversion rate of N is within the range of 100 to 550 DEG C 2 The selectivity of the catalyst is 95.4-100%, which shows that the monolithic catalyst prepared by the invention has excellent low-temperature catalytic activity, wider active temperature window, good hydrothermal aging resistance and high nitrogen selectivity.
Drawings
FIG. 1 is an XRD pattern of Cu-Y-SAPO-34-ed prepared by examples 1 to 6;
FIG. 2 is a graph of the pore size distribution of the Cu-Y-SAPO-34-ed prepared in example 4;
FIG. 3 is NH of Cu-Y-SAPO-34-ed prepared by example 4 3 -TPD map.
Detailed Description
The invention provides a preparation method of a hydrothermal stability resistant denitration catalyst, which comprises the following steps:
removing non-framework aluminum from the SAPO-34 molecular sieve by using a dilute phosphoric acid solution to obtain a non-framework aluminum removed SAPO-34 molecular sieve;
mixing the non-framework aluminum removed SAPO-34 molecular sieve with a rare earth metal saline solution, and carrying out ion exchange reaction to obtain rare earth modified SAPO-34;
placing the rare earth modified SAPO-34 into a mixed solution of copper precursor salt and ammonia water for dipping and then roasting to obtain rare earth modified Cu-SAPO-34;
and carrying out hydrothermal aging on the rare earth modified Cu-SAPO-34 in a water vapor-air mixed atmosphere to obtain the hydrothermal stability resistant denitration catalyst.
In the present invention, unless otherwise specified, all the raw material components are commercially available products well known to those skilled in the art.
The method utilizes dilute phosphoric acid solution to remove non-framework aluminum from the SAPO-34 molecular sieve to obtain the non-framework aluminum removed SAPO-34 molecular sieve.
In the present invention, the concentration of the diluted phosphoric acid solution is preferably 0.01 to 1mol/L, more preferably 0.2 to 0.7mol/L, and most preferably 0.3 to 0.6mol/L. In the invention, the temperature of the non-framework aluminum removing treatment is preferably 30-60 ℃, more preferably 40-50 ℃, and most preferably 45 ℃; the time for the non-framework aluminum removal treatment is preferably 30 to 120min, more preferably 50 to 100min, and most preferably 60 to 90min.
After the non-framework aluminum removed SAPO-34 molecular sieve is obtained, the non-framework aluminum removed SAPO-34 molecular sieve and the rare earth metal saline solution are mixed for ion exchange reaction to obtain the rare earth modified SAPO-34 (rare earth-SAPO-34).
In the invention, the rare earth metal salt in the rare earth metal salt aqueous solution preferably comprises one or more of water-soluble cerium salt, water-soluble lanthanum salt and water-soluble yttrium salt; the water-soluble cerium salt is preferably cerium nitrate; the water-soluble lanthanum salt is preferably lanthanum nitrate; the water-soluble yttrium salt is preferably yttrium nitrate. In the present invention, the concentration of the aqueous rare earth metal salt solution is preferably 0.01 to 1mol/L, more preferably 0.2 to 0.7mol/L, and most preferably 0.3 to 0.6mol/L.
In the present invention, the mixing method is preferably stirring mixing, and the speed and time of the stirring mixing are not particularly limited in the present invention, and the raw materials may be uniformly mixed.
In the present invention, the temperature of the ion exchange reaction is preferably 80 to 120 ℃, more preferably 90 to 110 ℃, and most preferably 100 ℃; the time of the ion exchange reaction is preferably 4 to 12 hours, more preferably 6 to 10 hours, and most preferably 8 to 10 hours. In the invention, during the ion exchange reaction, rare earth metal ions replace part of NH in the SAPO-34 molecular sieve 4 + (ii) a The exchange rate of the ion exchange is preferably 10% or less, more preferably 1 to 10%, most preferably 5%.
After the ion exchange reaction, the invention preferably further comprises the steps of carrying out solid-liquid separation on a system of the ion exchange reaction, washing the obtained solid component and then drying to obtain the rare earth modified SAPO-34. The solid-liquid separation method is not particularly limited, and a solid-liquid separation method known to those skilled in the art, such as filtration, may be employed. In the present invention, the solvent used for the washing preferably includes water and/or anhydrous ethanol; the number of washing is preferably 3 to 5, more preferably 4; the amount of the washing solvent used in the present invention is not particularly limited, and the aqueous solution of the rare earth metal salt remaining on the surface of the solid product and the exchanged NH can be removed 4 + And (5) removing. In the present invention, the temperature of the drying is preferably 60 to 100 ℃, more preferably 70 to 90 ℃, and most preferably 80 ℃; the drying time is preferably 12 to 48 hours, more preferably 20 to 40 hours, and most preferably 25 to 30 hours.
After the rare earth modified SAPO-34 is obtained, the rare earth modified SAPO-34 is placed in a mixed solution of copper precursor salt and ammonia water for dipping and then is roasted to obtain the rare earth modified Cu-SAPO-34 (Cu-rare earth-SAPO-34).
In the present invention, the copper precursor salt preferably includes one or more of copper nitrate, copper acetate and copper sulfate. In the present invention, the mass ratio of copper in the rare earth modified SAPO-34 molecular sieve and the copper precursor salt is preferably 93 to 99, more preferably 94 to 6 to 98, and most preferably 95 to 97. In the present invention, the concentration of the aqueous ammonia is 0.01 to 0.5mol/L, more preferably 0.05 to 0.4mol/L, and most preferably 0.1 to 0.3mol/L. In the present invention, the concentration of copper in the mixed solution is preferably 0.05 to 0.5mol/L, and more preferably 0.15 to 0.3mol/L.
In the present invention, the temperature of the impregnation is preferably 30 to 80 ℃, more preferably 40 to 70 ℃, and most preferably 50 to 60 ℃; the time for the impregnation is preferably 2 to 8 hours, more preferably 3 to 7 hours, and most preferably 4 to 6 hours; the impregnation is preferably carried out under the heating condition of a water bath; the vessel used for the impregnation is not particularly limited in the present invention, and a vessel well known to those skilled in the art may be used, and in the specific embodiment of the present invention, the impregnation is preferably performed in a beaker. The invention adopts a dipping and mixing mode, which is beneficial to better dispersing the active components on the molecular sieve carrier.
After the impregnation, the invention preferably further comprises drying the obtained impregnated product, wherein the drying temperature is preferably 80-120 ℃, and more preferably 90-110 ℃; the drying time is preferably 6 to 24 hours, more preferably 8 to 12 hours.
In the present invention, the temperature of the roasting is preferably 500 to 700 ℃, more preferably 550 to 650 ℃, and most preferably 600 ℃; the roasting time is preferably 2 to 6 hours, more preferably 3 to 5 hours, and most preferably 3 hours. In the invention, the active component copper is loaded on the SAPO-34 modified by rare earth in the roasting process, and specifically, the copper is firstly Cu 2+ Cation (NH) occupying form of SAPO-34 4 + ) Exchange sites, but Cu 2+ The exchange capacity of the catalyst is limited, and a small amount of free copper is formed into CuO which is dispersed in or out of the pore canal of the molecular sieve in the roasting process.
After the rare earth modified Cu-SAPO-34 is obtained, the rare earth modified Cu-SAPO-34 is subjected to hydrothermal aging in a water vapor-air mixed atmosphere to obtain the water-heat resistant stable denitration catalyst (Cu-rare earth-SAPO-34-agent).
In the present invention, the water vaporThe volume fraction of water vapor in the gas-air mixed atmosphere is preferably 4 to 12%, more preferably 6 to 9%, most preferably 7 to 8%. In the present invention, the temperature of the hydrothermal aging is preferably 600 to 800 ℃, more preferably 650 to 750 ℃; the hydrothermal aging time is preferably 3 to 15 hours, more preferably 5 to 12 hours, and most preferably 8 to 10 hours. In the invention, during the hydrothermal aging process, the rare earth metal ions can not only stabilize the framework Al of the SAPO-34 molecular sieve, but also inhibit the generation of substitutional Cu 2+ Migration and aggregation occur, and the catalyst has good stabilizing effect on the framework of the SAPO-34 molecular sieve, so that the hydrothermal stability of the denitrification catalyst with hydrothermal stability is improved. The structure of the molecular sieve of the catalyst which is not modified by rare earth is destroyed after hydrothermal aging, and the active Cu 2+ The species is converted to CuO, resulting in severe deactivation of the catalyst.
The invention provides a hydrothermal stability resistant denitration catalyst prepared by the preparation method of the technical scheme. In the invention, the anti-hydrothermal-stability denitration catalyst comprises a rare earth metal ion substituted SAPO-34 molecular sieve and an active component, wherein the active component comprises Cu 2+ And/or CuO, the rare earth metal ion and Cu 2+ NH located in the SAPO-34 molecular sieve 4 + On the site, the CuO is positioned in the pore canal and outside the pore canal of the SAPO-34 molecular sieve.
In the invention, in the anti-hydrothermal-stability denitration catalyst, the mass of Cu is preferably 1-10%, more preferably 2-8% and most preferably 3-7% of that of the SAPO-34 molecular sieve; the mass of the rare earth metal is preferably 0.1 to 10%, more preferably 0.5 to 8%, and most preferably 1 to 5% of the hydrothermal stability resistant denitration catalyst.
The invention provides a monolithic catalyst, which comprises cordierite and a catalytic component coated on the surface of the cordierite; the catalytic component comprises the anti-hydrothermal stable denitration catalyst.
In the present invention, the cordierite preferably has a pore diameter of 0.1 to 1mm, more preferably 0.3 to 0.8mm, and most preferably 0.5 to 0.6mm. The catalyst takes cordierite as a substrate of the catalyst, so that reaction gas can be fully contacted with active components, and the denitration efficiency is improved; moreover, compared with other carriers, the cordierite has small pressure drop, and the open straight channels can treat exhaust gas containing more particulate matters and smoke dust; the mechanical strength is high in a mobile source denitration system; the tolerance is strong, the thermal stability is good, and the expansion and deformation are not easy to occur; the price is low.
In the present invention, the catalytic component further includes an aluminum sol, and the present invention is not particularly limited to the aluminum sol, and any aluminum sol known to those skilled in the art may be used.
In the invention, the mass ratio of the hydrothermal-resistant stable denitration catalyst to the aluminum sol is preferably 1: (0.05 to 0.3), more preferably 1: (0.1-0.2).
In the present invention, the preparation method of the monolithic catalyst preferably comprises the following steps: mixing a hydrothermal-resistant stable denitration catalyst with water, adding alumina sol, and mixing to obtain slurry; and coating the slurry on the surface of cordierite, and drying to obtain the monolithic catalyst. In the invention, the mass ratio of the hydrothermal stability resistant denitration catalyst to water is preferably 1: (1 to 5), more preferably 1: (2-4). In the present invention, the coating is preferably performed by dipping; the temperature of the impregnation is preferably room temperature, and the time of the impregnation is preferably 20 to 60min, and more preferably 30 to 50min. The invention preferably also comprises drying after blowing off residual slurry in the coated product pore channels; the drying temperature is preferably 80-120 ℃, and more preferably 90-100 ℃; the drying time is preferably 1 to 2 hours, more preferably 1.5 hours. In the invention, the coating amount of the anti-hydrothermal stable denitration catalyst is preferably 100-200 g/L, more preferably 120-180 g/L, and most preferably 150-160 g/L; the coating amount of the aluminum sol is preferably 20 to 40g/L, and more preferably 30g/L. The coating method of the present invention is not particularly limited, and a coating method known to those skilled in the art may be used.
The invention also provides the application of the anti-hydrothermal stability denitration catalyst or the monolithic catalyst in the technical scheme in selective reduction of nitrogen oxides.
In the present invention, the method of application preferably comprises the steps of: the catalyst is placed in a fixed bed fluidity reactor, and reaction gas is introduced for selective reduction reaction. In the invention, the catalyst is the anti-hydrothermal stable denitration catalyst or the monolithic catalyst. In the present invention, the reaction gas is NH 3 、NO、O 2 And N 2 In the mixed gas of (1), NH 3 And the volume concentration of NO is independently preferably 400 to 800ppm, more preferably 600ppm; o in the mixed gas 2 The volume concentration of (b) is preferably 2 to 10%, more preferably 5%. In the present invention, the total flow rate of the mixed gas is preferably 200 to 600mL/min, more preferably 400mL/min; the space velocity is preferably 40000-100000 h -1 More preferably 60000h -1 . In the present invention, the amount of the catalyst to be used is preferably 0.1 to 0.6mL, more preferably 0.2 to 0.5mL. In the present invention, the temperature of the selective reduction reaction is preferably 150 to 500 ℃, more preferably 175 to 450 ℃, and most preferably 200 to 400 ℃.
The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. It should be apparent that the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1
(1) Placing the SAPO-34 molecular sieve in a dilute nitric acid solution with the concentration of 0.5mol/L, removing non-framework aluminum for 60min at the temperature of 45 ℃, filtering and naturally drying, placing the obtained SAPO-34 molecular sieve without the non-framework aluminum in a cerium nitrate solution with the concentration of 0.6mol/L, carrying out ion exchange for 12h in a water bath at the temperature of 80 ℃, filtering, washing the obtained solid product with deionized water for 5 times, and then drying for 12h at the temperature of 80 ℃ to obtain Ce-SAPO-34;
(2) Adding the Ce-SAPO-34 and copper nitrate into 5mL of ammonia water solution with the concentration of 0.1mol/L according to the mass ratio of SAPO-34 to copper being 97, stirring for 6h under the condition of water bath at 60 ℃, drying the obtained impregnation product at 100 ℃ for 12h, and roasting for 3h at 500 ℃ to obtain Cu-Ce-SAPO-34;
(3) Carrying out hydrothermal aging treatment on Cu-Ce-SAPO-34 for 10h in a water vapor-air mixed atmosphere at the temperature of 750 ℃ to obtain Cu-Ce-SAPO-34-agent, wherein the volume fraction of water vapor in the mixed atmosphere is 5%;
(4) Coating Cu-Ce-SAPO-34-agent, mixing with water, adding alumina sol, and uniformly mixing to obtain slurry; and (2) dipping cordierite with the pore diameter of 0.1-1 mm in the slurry for 50min, taking out, blowing out residual slurry in product pore channels, and drying at 80 ℃ for 1.5h to obtain the monolithic catalyst, wherein the coating amount of Cu-Ce-SAPO-34-agent is 160g/L, and the mass ratio of the anti-hydrothermal stable denitration catalyst to the alumina sol to the water is 1:0.2:1.93.
example 2
(1) Placing the SAPO-34 molecular sieve in a dilute nitric acid solution with the concentration of 0.5mol/L, removing non-framework aluminum for 60min at the temperature of 45 ℃, filtering and naturally drying, placing the obtained SAPO-34 molecular sieve without the non-framework aluminum in a lanthanum nitrate solution with the concentration of 0.6mol/L, heating in a water bath at the temperature of 80 ℃ for 12h, carrying out ion exchange and filtration, washing the obtained solid product with deionized water for 5 times, and then drying at the temperature of 80 ℃ for 12h to obtain La-SAPO-34;
(2) Adding the La-SAPO-34 and copper nitrate into 5mL of ammonia water solution with the concentration of 0.1mol/L according to the mass ratio of SAPO-34 to copper of 97, stirring for 6h under the condition of water bath at 60 ℃, drying the obtained impregnation product at 100 ℃ for 12h, and roasting for 3h at 500 ℃ to obtain Cu-La-SAPO-34;
(3) Carrying out hydrothermal aging treatment on Cu-La-SAPO-34 for 10h in a water vapor-air mixed atmosphere at the temperature of 750 ℃ to obtain Cu-La-SAPO-34-agent, wherein the volume fraction of water vapor in the mixed atmosphere is 5%;
(4) Mixing Cu-La-SAPO-34-aid with water, adding alumina sol, and uniformly mixing to obtain slurry; dipping cordierite with the pore diameter of 0.1-1 mm in the slurry for 30min, taking out, blowing off residual slurry in a product pore channel, and drying at 120 ℃ for 1.5h to obtain the monolithic catalyst, wherein the coating amount of Cu-La-SAPO-34-agent is 160g/L, and the mass ratio of the hydrothermal-resistant stable denitration catalyst to aluminum sol to water is 1:0.13:2.
example 3
(1) Placing the SAPO-34 molecular sieve in a dilute nitric acid solution with the concentration of 0.5mol/L, removing non-framework aluminum for 60min at the temperature of 45 ℃, filtering and naturally drying, placing the obtained non-framework aluminum-removed SAPO-34 molecular sieve in an yttrium nitrate solution with the concentration of 0.6mol/L, heating in a water bath at the temperature of 80 ℃ for 12h, carrying out ion exchange and filtration, washing the obtained solid product with deionized water for 5 times, and then drying at the temperature of 80 ℃ for 12h to obtain Y-SAPO-34;
(2) Adding the Y-SAPO-34 and copper nitrate into 5mL of ammonia water solution with the concentration of 0.1mol/L according to the mass ratio of SAPO-34 to copper of 97, stirring for 6h under the condition of water bath at 60 ℃, drying the obtained impregnation product at 100 ℃ for 12h, and roasting for 3h at 500 ℃ to obtain Cu-Y-SAPO-34;
(3) Carrying out hydrothermal aging treatment on Cu-Y-SAPO-34 for 10h in a water vapor-air mixed atmosphere at the temperature of 750 ℃ to obtain Cu-Y-SAPO-34-agent, wherein the volume fraction of water vapor in the mixed atmosphere is 5%;
(4) Mixing Cu-Y-SAPO-34-aid with water, adding alumina sol, and uniformly mixing to obtain slurry; dipping cordierite with the pore diameter of 0.1-1 mm into the slurry for 20min, taking out, blowing off residual slurry in a product pore channel, and drying at 100 ℃ for 1.5h to obtain the monolithic catalyst, wherein the coating amount of Cu-Y-SAPO-34-agent is 160g/L, and the mass ratio of the hydrothermal-resistant stable denitration catalyst to aluminum sol to water is 1:0.19:1.94.
example 4
(1) Placing the SAPO-34 molecular sieve in a dilute nitric acid solution with the concentration of 0.5mol/L, removing non-framework aluminum for 60min at the temperature of 45 ℃, filtering and naturally drying, placing the obtained non-framework aluminum-removed SAPO-34 molecular sieve in an yttrium nitrate solution with the concentration of 0.3mol/L, heating in a water bath at the temperature of 80 ℃ for 12h, carrying out ion exchange and filtration, washing the obtained solid product with deionized water for 5 times, and then drying at the temperature of 80 ℃ for 12h to obtain Y-SAPO-34;
(2) Adding the Y-SAPO-34 and copper nitrate into 5mL of 0.1mol/L ammonia water solution according to the mass ratio of SAPO-34 to copper being 98, stirring for 6h under the condition of 60 ℃ water bath, drying the obtained impregnated product at 100 ℃ for 12h, and roasting for 3h at 500 ℃ to obtain Cu-Y-SAPO-34;
(3) Carrying out hydrothermal aging treatment on Cu-Y-SAPO-34 for 10h in a water vapor-air mixed atmosphere at the temperature of 750 ℃ to obtain Cu-Y-SAPO-34-agent, wherein the volume fraction of water vapor in the mixed atmosphere is 5%;
(4) Mixing Cu-Y-SAPO-34-aid with water, adding alumina sol, and uniformly mixing to obtain slurry; dipping cordierite with the pore diameter of 0.1-1 mm in the slurry for 40min, taking out, blowing off residual slurry in a product pore channel, and drying at 120 ℃ for 1.5h to obtain the monolithic catalyst, wherein the coating amount of Cu-Y-SAPO-34-agent is 160g/L, and the mass ratio of the hydrothermal-resistant stable denitration catalyst to aluminum sol to water is 1:0.2:1.93.
example 5
(1) Placing the SAPO-34 molecular sieve in a dilute nitric acid solution with the concentration of 0.5mol/L, removing non-framework aluminum for 60min at the temperature of 45 ℃, filtering and naturally drying, placing the obtained non-framework aluminum-removed SAPO-34 molecular sieve in an yttrium nitrate solution with the concentration of 0.3mol/L, heating in a water bath at the temperature of 80 ℃ for 12h, carrying out ion exchange and filtration, washing the obtained solid product with deionized water for 5 times, and then drying at the temperature of 80 ℃ for 12h to obtain Y-SAPO-34;
(2) Adding the Y-SAPO-34 and copper acetate into 5mL of 0.1mol/L ammonia water solution according to the mass ratio of SAPO-34 to copper being 98, stirring for 6h under the condition of 60 ℃ water bath, drying the obtained impregnation product at 100 ℃ for 12h, and roasting for 3h at 500 ℃ to obtain Cu-Y-SAPO-34;
(3) Carrying out hydrothermal aging treatment on Cu-Y-SAPO-34 for 10h in a water vapor-air mixed atmosphere at the temperature of 750 ℃ to obtain Cu-Y-SAPO-34-agent, wherein the volume fraction of water vapor in the mixed atmosphere is 5%;
(4) Mixing Cu-Y-SAPO-34-ged and water, adding alumina sol, and uniformly mixing to obtain slurry; and (2) dipping cordierite with the pore diameter of 0.1-1 mm in the slurry for 50min, taking out, blowing out residual slurry in product pore channels, and drying at 80 ℃ for 1.5h to obtain the monolithic catalyst, wherein the coating amount of Cu-Y-SAPO-34-agent is 160g/L, and the mass ratio of the anti-hydrothermal stable denitration catalyst to the alumina sol to the water is 1:0.13:2.
example 6
(1) Placing the SAPO-34 molecular sieve in a dilute nitric acid solution with the concentration of 0.5mol/L, removing non-framework aluminum for 60min at the temperature of 45 ℃, filtering and naturally drying, placing the obtained non-framework aluminum-removed SAPO-34 molecular sieve in an yttrium nitrate solution with the concentration of 0.3mol/L, heating in a water bath at the temperature of 80 ℃ for 12h, carrying out ion exchange and filtration, washing the obtained solid product with deionized water for 5 times, and then drying at the temperature of 80 ℃ for 12h to obtain Y-SAPO-34;
(2) Adding the Y-SAPO-34 and copper acetate into 5mL of 0.1mol/L ammonia water solution according to the mass ratio of SAPO-34 to copper being 98, stirring for 6h under the condition of 60 ℃ water bath, drying the obtained impregnation product at 100 ℃ for 12h, and roasting for 3h at 500 ℃ to obtain Cu-Y-SAPO-34;
(3) Carrying out hydrothermal aging treatment on Cu-Y-SAPO-34 for 10h in a water vapor-air mixed atmosphere at the temperature of 750 ℃ to obtain Cu-Y-SAPO-34-aid, wherein the volume fraction of water vapor in the mixed atmosphere is 10%;
(4) Mixing Cu-Y-SAPO-34-ged and water, adding alumina sol, and uniformly mixing to obtain slurry; and (2) dipping cordierite with the pore diameter of 0.1-1 mm in the slurry for 50min, taking out, blowing out residual slurry in product pore channels, and drying at 100 ℃ for 1.5h to obtain the monolithic catalyst, wherein the coating amount of Cu-Y-SAPO-34-agent is 160g/L, and the mass ratio of the anti-hydrothermal stable denitration catalyst to the alumina sol to the water is 1:0.19:1.94.
the XRD patterns of the Cu-Y-SAPO-34-formed materials prepared in examples 1 to 6 are shown in FIG. 1, and it can be seen from FIG. 1 that the Cu-Y-SAPO-34-formed materials prepared in examples 1 to 6 of the present invention all have SAPO-34 structure.
The pore size distribution of Cu-Y-SAPO-34-ed prepared in example 4 is shown in FIG. 2, and it can be seen from FIG. 2 that Cu-Y-SAPO-34-ed has a rich pore structure.
NH of Cu-Y-SAPO-34-ed prepared in example 4 3 FIG. 3 shows a TPD diagram, and it can be seen from FIG. 3 that the Cu-Y-SAPO-34-formed toolHas abundant acidic sites.
Example 7
(1) Placing the SAPO-34 molecular sieve in a dilute nitric acid solution with the concentration of 0.5mol/L, removing non-framework aluminum at the temperature of 45 ℃, treating for 60min, filtering, naturally drying the obtained solid components in air, placing the obtained non-framework aluminum-removed SAPO-34 molecular sieve in an yttrium nitrate solution with the concentration of 0.3mol/L, heating for 12h in a water bath at the temperature of 80 ℃, carrying out ion exchange, filtering, washing the obtained solid product with deionized water for 5 times, and then drying for 12h at the temperature of 80 ℃ to obtain Y-SAPO-34;
(2) Adding the Y-SAPO-34 and copper acetate into 5mL of 0.1mol/L ammonia water solution according to the mass ratio of SAPO-34 to copper of 99, stirring for 6h under the condition of 60 ℃ water bath, drying the obtained impregnation product at 100 ℃ for 12h, and roasting at 600 ℃ for 3h to obtain Cu-Y-SAPO-34;
(3) Carrying out hydrothermal aging treatment on Cu-Y-SAPO-34 for 10h in a water vapor-air mixed atmosphere at the temperature of 750 ℃ to obtain Cu-Y-SAPO-34-agent, wherein the volume fraction of water vapor in the mixed atmosphere is 10%;
(4) And coating the Cu-Y-SAPO-34-agent on cordierite with the pore diameter of 0.1-1 mm to obtain the monolithic catalyst, wherein the coating amount of the Cu-Y-SAPO-34-agent is 160g/L.
Example 8
(1) Placing the SAPO-34 molecular sieve in a dilute nitric acid solution with the concentration of 0.5mol/L, removing non-framework aluminum for 60min at the temperature of 45 ℃, filtering and naturally drying, placing the obtained non-framework aluminum-removed SAPO-34 molecular sieve in an yttrium nitrate solution with the concentration of 0.3mol/L, heating in a water bath at the temperature of 80 ℃ for 12h, carrying out ion exchange and filtration, washing the obtained solid product with deionized water for 5 times, and then drying at the temperature of 80 ℃ for 12h to obtain Y-SAPO-34;
(2) Adding the Y-SAPO-34 and copper acetate into an ammonia water solution with the concentration of 0.1mol/L according to the weight ratio of SAPO-34 to copper of 93;
(3) Carrying out hydrothermal aging treatment on Cu-Y-SAPO-34 for 10h in a water vapor-air mixed atmosphere at the temperature of 750 ℃ to obtain Cu-Y-SAPO-34-agent, wherein the volume fraction of water vapor in the mixed atmosphere is 10%;
(4) And coating the Cu-Y-SAPO-34-agent on cordierite with the pore diameter of 0.1-1 mm to obtain the monolithic catalyst, wherein the coating amount of the Cu-Y-SAPO-34-agent is 160g/L.
Example 9
Cu-Y-SAPO-34 and monolithic catalyst were prepared as in example 6, except that the yttrium nitrate solution was at a concentration of 0.01mol/L.
Example 10
Cu-Y-SAPO-34 and monolithic catalyst were prepared as in example 6, except that the yttrium nitrate solution was at a concentration of 0.7mol/L.
Example 11
Cu-Y-SAPO-34 and a monolithic catalyst were prepared as in example 6, with the exception that the mixed atmosphere had a 4% volume fraction of water vapor.
Example 12
Cu-Y-SAPO-34 and monolithic catalyst were prepared as in example 6, except that the volume fraction of water vapor in the mixed atmosphere was 11%.
Example 13
Cu-Y-SAPO-34 and monolithic catalyst were prepared as in example 6, except that hydrothermal aging was carried out at 600 ℃ for 15h.
Example 14
Cu-Y-SAPO-34 and a monolithic catalyst were prepared as in example 6, with the difference that the hydrothermal aging temperature was 800 ℃ and the hydrothermal aging time was 3 hours.
Comparative example 1
And (3) coating the prepared Cu-Ce-SAPO-34 obtained in the step (2) in the example 1 on cordierite with the pore diameter of 0.1-1 mm to obtain an integral catalyst, wherein the coating amount of the Cu-Ce-SAPO-34 is 160g/L.
Comparative example 2
The prepared Cu-La-SAPO-34 obtained in the step (2) of the example 2 is coated on cordierite with the pore diameter of 0.1-1 mm to obtain a monolithic catalyst, wherein the coating amount of the Cu-La-SAPO-34 is 160g/L.
Comparative example 3
The prepared Cu-Y-SAPO-34 obtained in the step (2) of example 3 is coated on cordierite with the pore diameter of 0.1-1 mm to obtain a monolithic catalyst, wherein the coating amount of the Cu-Y-SAPO-34 is 160g/L.
Comparative example 4
The prepared Cu-Y-SAPO-34 obtained in the step (2) of the example 4 is coated on cordierite with the pore diameter of 0.1-1 mm to obtain a monolithic catalyst, wherein the coating amount of the Cu-Y-SAPO-34 is 160g/L.
Comparative example 5
The prepared Cu-Y-SAPO-34 obtained in the step (2) of example 5 is coated on cordierite with the pore diameter of 0.1-1 mm to obtain a monolithic catalyst, wherein the coating amount of the Cu-Y-SAPO-34 is 160g/L.
Comparative example 6
The prepared Cu-Y-SAPO-34 obtained in step (2) of example 6 was coated on cordierite having a pore size of 0.1 to 1mm to obtain a monolithic catalyst, wherein the coating amount of the Cu-Y-SAPO-34 was 160g/L.
Comparative example 7
(1) Adding the SAPO-34 molecular sieve and copper nitrate into a ball mill for ball milling for 6h, then roasting for 3h at 500 ℃, washing for 5 times by using absolute ethyl alcohol, and drying for 12h at 80 ℃ to obtain Cu-SAPO-34; the mass ratio of the SAPO-34 molecular sieve to copper in the copper nitrate is 97;
(2) And (3) coating the Cu-SAPO-34 on cordierite with the pore diameter of 0.1-1 mm to obtain the monolithic catalyst, wherein the coating amount of the Cu-SAPO-34 is 160g/L.
Comparative example 8
(1) Adding the SAPO-34 molecular sieve and copper nitrate into a ball mill for ball milling for 6h, then roasting for 3h at 500 ℃, washing for 5 times by using absolute ethyl alcohol, and drying for 12h at 80 ℃ to obtain Cu-SAPO-34; the mass ratio of the SAPO-34 molecular sieve to copper in the copper nitrate is 97;
(2) Carrying out hydrothermal aging treatment on Cu-SAPO-34 for 10h in a water vapor-air mixed atmosphere at the temperature of 750 ℃ to obtain Cu-SAPO-34-agent, wherein the volume fraction of water vapor in the mixed atmosphere is 5%;
(3) And coating the Cu-SAPO-34-agent on cordierite with the pore diameter of 0.1-1 mm to obtain the monolithic catalyst, wherein the coating amount of the Cu-SAPO-34-agent is 160g/L.
Application example 1
The monolithic catalysts prepared in examples 1 to 14 and comparative examples 1 to 8 were placed in a fixed bed flow reactor, and a selective reduction reaction was performed by introducing a reaction gas having a composition of 600ppm NH 3 +600ppmNO+5％O 2 +N 2 The total flow of the reaction gas is 400mL/min, and the space velocity is 60000h -1 The temperature of the selective reduction reaction is 150 to 500 ℃, and NO is catalyzed by the monolithic catalysts prepared in examples 1 to 14 and comparative examples 1 to 8 at different reaction temperatures x The conversion of (A) is shown in tables 1 to 3, NO x The temperature interval of the selective catalytic reduction reaction with a conversion rate of not less than 90% is shown in Table 4, N 2 The selectivity of (A) is shown in tables 5 to 7.
Table 1 the monolithic catalysts prepared in examples 1 to 6 catalyze NO at different reaction temperatures x Conversion rate of (2)
TABLE 2 integral catalysts prepared in comparative examples 1 to 8 catalyze NO at different reaction temperatures x Conversion rate of (2)
Table 3 the monolithic catalysts prepared in examples 9 to 14 catalyze NO at different reaction temperatures x Conversion rate of (2)
TABLE 4 NO catalyzed by monolithic catalysts prepared in examples 1 to 14 and comparative examples 1 to 8 x Temperature interval of selective catalytic reduction reaction with conversion rate of more than or equal to 90 percent
TABLE 5 catalysts prepared in examples 1-8 for catalyzing N at different reaction temperatures 2 Selectivity of (2)
TABLE 6 integral catalysts prepared in comparative examples 1 to 8 catalyze N at different reaction temperatures 2 Selectivity of (2)
Table 7 monolithic catalysts prepared in examples 9-14 catalyze N at different reaction temperatures 2 Selectivity of (2)
As can be seen from tables 1-7, the monolithic catalysts prepared according to the present invention selectively catalyze the reduction of NO x ，NO x The temperature range of the conversion rate of more than or equal to 90 percent is 140 to 480 ℃, and the temperature range is 100 to 550 DEG CPair of N in the enclosure 2 The selectivity of the catalyst is 95.4-100%, which shows that the catalyst prepared by the invention has excellent low-temperature catalytic activity, wider active temperature window, good hydrothermal aging resistance and high nitrogen selectivity.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
Claims (10)
1. A preparation method of a hydrothermal stability resistant denitration catalyst is characterized by comprising the following steps:
removing non-framework aluminum from the SAPO-34 molecular sieve by using a dilute phosphoric acid solution to obtain a non-framework aluminum removed SAPO-34 molecular sieve;
mixing the non-framework aluminum removed SAPO-34 molecular sieve with a rare earth metal saline solution, and carrying out ion exchange reaction to obtain rare earth modified SAPO-34;
placing the rare earth modified SAPO-34 into a mixed solution of copper precursor salt and ammonia water for dipping and then roasting to obtain rare earth modified Cu-SAPO-34;
and carrying out hydrothermal aging on the rare earth modified Cu-SAPO-34 in a water vapor-air mixed atmosphere to obtain the hydrothermal stability resistant denitration catalyst.
2. The preparation method of claim 1, wherein the concentration of the dilute phosphoric acid solution is 0.01-1 mol/L, the temperature of the non-framework aluminum removal treatment is 30-60 ℃, and the time is 20-120 min.
3. The method according to claim 1, wherein the rare earth metal salt in the aqueous solution of a rare earth metal salt comprises one or more of a water-soluble cerium salt, a water-soluble lanthanum salt, and a water-soluble yttrium salt; the concentration of the rare earth metal salt aqueous solution is 0.01-1 mol/L.
4. The method according to claim 1 or 2, wherein the temperature of the ion exchange reaction is 80 to 120 ℃ and the time is 4 to 12 hours.
5. The preparation method according to claim 1, wherein the mass ratio of copper in the rare earth modified SAPO-34 molecular sieve to copper precursor salt is 93 to 99;
the concentration of the ammonia water is 0.01-0.5 mol/L.
6. The method according to claim 1 or 5, wherein the impregnation is carried out at a temperature of 30 to 80 ℃ for 2 to 8 hours;
the roasting temperature is 500-700 ℃, and the roasting time is 2-6 h.
7. The preparation method according to claim 1, wherein the volume fraction of the water vapor in the water vapor-air mixed atmosphere is 4 to 12%;
the temperature of the hydrothermal aging is 600-800 ℃, and the time is 3-15 h.
8. The denitration catalyst with hydrothermal stability prepared by the preparation method of any one of claims 1 to 7.
9. A monolithic catalyst comprising cordierite and a catalytic component coated on the surface of the cordierite; the catalytic component comprises the hydrothermal stable denitration catalyst of claim 7.
10. Use of the hydrothermally stable denitration catalyst of claim 8 or the monolithic catalyst of claim 9 in selective reduction of nitrogen oxides.
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