CN117299195B - SCR catalyst with wide temperature window and preparation method and application thereof - Google Patents
SCR catalyst with wide temperature window and preparation method and application thereof Download PDFInfo
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- 239000003054 catalyst Substances 0.000 title claims abstract description 51
- 238000002360 preparation method Methods 0.000 title claims abstract description 17
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 claims abstract description 108
- URGAHOPLAPQHLN-UHFFFAOYSA-N sodium aluminosilicate Chemical compound [Na+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O URGAHOPLAPQHLN-UHFFFAOYSA-N 0.000 claims abstract description 92
- 239000002808 molecular sieve Substances 0.000 claims abstract description 91
- 230000000694 effects Effects 0.000 claims description 27
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 27
- 238000012360 testing method Methods 0.000 claims description 23
- 239000000463 material Substances 0.000 claims description 16
- 238000001035 drying Methods 0.000 claims description 13
- 239000007787 solid Substances 0.000 claims description 12
- 238000005342 ion exchange Methods 0.000 claims description 11
- 230000004913 activation Effects 0.000 claims description 8
- 239000008367 deionised water Substances 0.000 claims description 8
- 229910021641 deionized water Inorganic materials 0.000 claims description 8
- 238000000967 suction filtration Methods 0.000 claims description 8
- 238000005406 washing Methods 0.000 claims description 8
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 6
- 239000003638 chemical reducing agent Substances 0.000 claims description 5
- 229910052757 nitrogen Inorganic materials 0.000 claims description 3
- 229910052751 metal Inorganic materials 0.000 abstract description 36
- 239000002184 metal Substances 0.000 abstract description 36
- 238000000034 method Methods 0.000 abstract description 33
- 230000003197 catalytic effect Effects 0.000 abstract description 25
- 239000010949 copper Substances 0.000 description 48
- UNYSKUBLZGJSLV-UHFFFAOYSA-L calcium;1,3,5,2,4,6$l^{2}-trioxadisilaluminane 2,4-dioxide;dihydroxide;hexahydrate Chemical compound O.O.O.O.O.O.[OH-].[OH-].[Ca+2].O=[Si]1O[Al]O[Si](=O)O1.O=[Si]1O[Al]O[Si](=O)O1 UNYSKUBLZGJSLV-UHFFFAOYSA-L 0.000 description 41
- 229910052676 chabazite Inorganic materials 0.000 description 40
- 239000007789 gas Substances 0.000 description 25
- 230000000052 comparative effect Effects 0.000 description 21
- 238000006243 chemical reaction Methods 0.000 description 17
- 230000008569 process Effects 0.000 description 16
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 14
- 229910052802 copper Inorganic materials 0.000 description 14
- 239000011148 porous material Substances 0.000 description 12
- 239000012266 salt solution Substances 0.000 description 12
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 11
- 229910052717 sulfur Inorganic materials 0.000 description 11
- 239000011593 sulfur Substances 0.000 description 11
- 239000000243 solution Substances 0.000 description 10
- GQPLMRYTRLFLPF-UHFFFAOYSA-N Nitrous Oxide Chemical compound [O-][N+]#N GQPLMRYTRLFLPF-UHFFFAOYSA-N 0.000 description 9
- 238000010531 catalytic reduction reaction Methods 0.000 description 9
- 239000000203 mixture Substances 0.000 description 8
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical group O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 description 7
- 238000001914 filtration Methods 0.000 description 7
- 229910052760 oxygen Inorganic materials 0.000 description 7
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 6
- 238000002156 mixing Methods 0.000 description 6
- 238000000643 oven drying Methods 0.000 description 6
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 5
- 229910021536 Zeolite Inorganic materials 0.000 description 5
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 5
- 239000011261 inert gas Substances 0.000 description 5
- 238000011068 loading method Methods 0.000 description 5
- 229910052710 silicon Inorganic materials 0.000 description 5
- 239000010703 silicon Substances 0.000 description 5
- 239000010457 zeolite Substances 0.000 description 5
- 230000009286 beneficial effect Effects 0.000 description 4
- 229910052739 hydrogen Inorganic materials 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- QPLDLSVMHZLSFG-UHFFFAOYSA-N Copper oxide Chemical compound [Cu]=O QPLDLSVMHZLSFG-UHFFFAOYSA-N 0.000 description 3
- 229910052782 aluminium Inorganic materials 0.000 description 3
- 229910021529 ammonia Inorganic materials 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 230000000977 initiatory effect Effects 0.000 description 3
- 150000002500 ions Chemical class 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- MGWGWNFMUOTEHG-UHFFFAOYSA-N 4-(3,5-dimethylphenyl)-1,3-thiazol-2-amine Chemical compound CC1=CC(C)=CC(C=2N=C(N)SC=2)=C1 MGWGWNFMUOTEHG-UHFFFAOYSA-N 0.000 description 2
- 229910002651 NO3 Inorganic materials 0.000 description 2
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- ZWWCURLKEXEFQT-UHFFFAOYSA-N dinitrogen pentaoxide Chemical compound [O-][N+](=O)O[N+]([O-])=O ZWWCURLKEXEFQT-UHFFFAOYSA-N 0.000 description 2
- WFPZPJSADLPSON-UHFFFAOYSA-N dinitrogen tetraoxide Chemical compound [O-][N+](=O)[N+]([O-])=O WFPZPJSADLPSON-UHFFFAOYSA-N 0.000 description 2
- LZDSILRDTDCIQT-UHFFFAOYSA-N dinitrogen trioxide Chemical compound [O-][N+](=O)N=O LZDSILRDTDCIQT-UHFFFAOYSA-N 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- 239000003344 environmental pollutant Substances 0.000 description 2
- 238000005470 impregnation Methods 0.000 description 2
- 239000011259 mixed solution Substances 0.000 description 2
- JCXJVPUVTGWSNB-UHFFFAOYSA-N nitrogen dioxide Inorganic materials O=[N]=O JCXJVPUVTGWSNB-UHFFFAOYSA-N 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 231100000719 pollutant Toxicity 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 239000012495 reaction gas Substances 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 238000006722 reduction reaction Methods 0.000 description 2
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- 239000005751 Copper oxide Substances 0.000 description 1
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 description 1
- 238000003916 acid precipitation Methods 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 239000003463 adsorbent Substances 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- AZDRQVAHHNSJOQ-UHFFFAOYSA-N alumane Chemical group [AlH3] AZDRQVAHHNSJOQ-UHFFFAOYSA-N 0.000 description 1
- CSDREXVUYHZDNP-UHFFFAOYSA-N alumanylidynesilicon Chemical compound [Al].[Si] CSDREXVUYHZDNP-UHFFFAOYSA-N 0.000 description 1
- 229910000323 aluminium silicate Inorganic materials 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 229910000431 copper oxide Inorganic materials 0.000 description 1
- XTVVROIMIGLXTD-UHFFFAOYSA-N copper(II) nitrate Chemical compound [Cu+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O XTVVROIMIGLXTD-UHFFFAOYSA-N 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000009849 deactivation Effects 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000003517 fume Substances 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 238000011065 in-situ storage Methods 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000001272 nitrous oxide Substances 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000007142 ring opening reaction Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 238000007873 sieving Methods 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000001988 toxicity Effects 0.000 description 1
- 231100000419 toxicity Toxicity 0.000 description 1
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J29/00—Catalysts comprising molecular sieves
- B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
- B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
- B01J29/70—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of types characterised by their specific structure not provided for in groups B01J29/08 - B01J29/65
- B01J29/72—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of types characterised by their specific structure not provided for in groups B01J29/08 - B01J29/65 containing iron group metals, noble metals or copper
- B01J29/76—Iron group metals or copper
- B01J29/763—CHA-type, e.g. Chabazite, LZ-218
-
- 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
- B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
- B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
- B01D53/9404—Removing only nitrogen compounds
- B01D53/9409—Nitrogen oxides
- B01D53/9413—Processes characterised by a specific catalyst
- B01D53/9418—Processes characterised by a specific catalyst for removing nitrogen oxides by selective catalytic reduction [SCR] using a reducing agent in a lean exhaust gas
-
- 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
- B01J37/04—Mixing
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
- B01J37/08—Heat treatment
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
- B01J37/34—Irradiation by, or application of, electric, magnetic or wave energy, e.g. ultrasonic waves ; Ionic sputtering; Flame or plasma spraying; Particle radiation
- B01J37/341—Irradiation by, or application of, electric, magnetic or wave energy, e.g. ultrasonic waves ; Ionic sputtering; Flame or plasma spraying; Particle radiation making use of electric or magnetic fields, wave energy or particle radiation
- B01J37/344—Irradiation by, or application of, electric, magnetic or wave energy, e.g. ultrasonic waves ; Ionic sputtering; Flame or plasma spraying; Particle radiation making use of electric or magnetic fields, wave energy or particle radiation of electromagnetic wave energy
- B01J37/346—Irradiation by, or application of, electric, magnetic or wave energy, e.g. ultrasonic waves ; Ionic sputtering; Flame or plasma spraying; Particle radiation making use of electric or magnetic fields, wave energy or particle radiation of electromagnetic wave energy of microwave energy
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2258/00—Sources of waste gases
- B01D2258/01—Engine exhaust gases
- B01D2258/012—Diesel engines and lean burn gasoline engines
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Abstract
The invention relates to the technical field of SCR catalysts, and discloses a wide temperature window SCR catalyst, a preparation method and application thereof. After the metal-loaded molecular sieve prepared by the method is subjected to microwave treatment, the catalytic performance of the molecular sieve can be remarkably improved, the temperature window is expanded from the conventional temperature of 250-400 ℃ to the temperature range of 150-550 ℃, and the catalytic efficiency on nitrogen oxides is kept very good even under the condition of low temperature or high temperature.
Description
Technical Field
The invention relates to the technical field of SCR catalysts, in particular to a wide temperature window SCR catalyst, a preparation method and application thereof.
Background
Nitrogen oxide NO in tail gas generated by oxygen-enriched lean combustion of diesel engine x (NO and NO) 2 ) Has become road NO x The main source of emission is that the emission amount reaches more than 70% of the total emission amount of the mobile source of the motor vehicle. NO (NO) x Serious environmental problems such as photochemical smog, acid rain, ozone generation and the like can be caused. Increasingly stringent emission standards, NO, are beginning to be implemented throughout the country x The emission limit was reduced from 60 mg/km to 35 mg/km. Currently, ammonia selective catalytic reduction (NH 3 -SCR) is considered to eliminate NO x By the most efficient technique of using SCR catalyst and adding reductant NH 3 NO is carried out under the oxygen-enriched condition of 290-400 DEG C x Selective catalytic reduction to N 2 。
Compared with carriers such as metal oxide, the molecular sieve material has the advantages of unique pore channel structure, regular pore size distribution, larger specific surface area, rich ion exchange sites and the like, and has more and more outstanding application value in the aspect of purifying tail gas pollutants of motor vehicles. Compared with molecular sieves with relatively large equivalent pore sizes of ZSM-5 and Beta and generating more macromolecular hydrocarbons in the reaction, the eight-membered ring small pore molecular sieve has a small pore structure, so that the eight-membered ring small pore molecular sieve has relatively excellent small molecular shape selectivity, carbon deposition resistance and the like, and is widely applied to the removal of tail gas pollutants of motor vehicles in recent years. Wherein SSZ-13 molecular sieve with CHA topological structure is prepared by introducing copper (Cu) by ion exchange and drying, roasting and heat treating to obtain catalyst pair NO x The removal rate is 90The active temperature window (i.e., T90) of% and above is typically 180-450 ℃, and can also exhibit good hydrothermal stability and N 2 The selectivity is increasingly applied to the field of diesel vehicle denitration catalysts.
The He Hong team of the national academy of sciences discovers that the Cu loading amount is 1.7 to 4.8 weight percent, which is most beneficial to NH of Cu-SSZ-13 3 -SCR performance. In order to study the denitration activity of Cu-SSZ-13 along with the change of temperature, scientific researchers have made many researches in terms of simulating the working conditions of different mileage of vehicle operation, and the result shows that Cu-SSZ-13 has excellent denitration performance in a medium temperature range window. Compared with the T90 activity temperature window (280-460 ℃) obtained by an ion exchange method, the 2wt% Cu-SSZ-13 prepared by the dipping method of the Chinese petroleum university (Huadong) Liu Yun team has wider range of 220-480 ℃, has higher denitration activity at high temperature, and is considered to be possibly that the Cu-SSZ-13 prepared by the ion exchange method contains more Cu (OH) + Z species, which tend to transform into clusters of less chemically active CuO, affecting catalytic activity. The denitration activity of Cu-SSZ-13 with Cu loading capacity of 3.8wt% prepared by He Hong team by adopting one-step in-situ method in the medium temperature range of 250-450 ℃ is higher than 90%, and enough Cu is found out 2+ The ions can exhibit higher NH 3 SCR Activity, while excessive Cu 2+ Ions are easy to accumulate to form CuO x Clusters, which cause collapse of the zeolite structure during hydrothermal aging and thus deactivation.
In general, cu/small pore molecular sieves are considered to be the most promising SCR catalyst materials. However, NO in the low temperature portion and the high temperature portion x There is still a large space for improving the catalytic activity.
Disclosure of Invention
The invention aims to provide a wide temperature window SCR catalyst, a preparation method and application thereof, and a molecular sieve loaded with metal is treated by microwaves, so that the temperature window for selective catalytic reduction of nitrogen oxides is remarkably widened, and NO in a low-temperature part and a high-temperature part of an SCR catalyst material in the prior art is solved x The catalytic activity still has the technical problem of great promotion space.
The invention provides a preparation method of a wide temperature window SCR catalyst, which comprises the following steps:
s1, preparing a CHA molecular sieve loaded with metal;
s2, carrying out microwave treatment on the CHA molecular sieve loaded with the metal to obtain a catalyst;
the metal is Cu, and the mass ratio of Cu element to the molecular sieve in the catalyst is 0.1-10.0%.
Further, the mass ratio of Cu element to the molecular sieve in the catalyst is 0.5-4.5%.
Further, in S2, the microwave treatment includes: and carrying out microwave treatment for 5-90 min under the conditions of the power density of 1500-3000W/g and the temperature of 50-220 ℃.
Further, in the step S2, in the microwave treatment process, inert gas is continuously introduced, and the flow rate of the inert gas is 20-500mL/min.
Further, in S1, preparing a metal-loaded CHA molecular sieve comprises: mixing a soluble salt solution of a metal element with the CHA molecular sieve to obtain a mixture, and roasting solid matters in the mixture at the temperature of 350-600 ℃ to obtain the metal-loaded CHA molecular sieve.
Further, the ratio of the amount of the substances of the silicon element to the aluminum element in the CHA molecular sieve is 10-25.
Further, the CHA-type molecular sieve has a ratio of the amount of elemental silicon to the amount of elemental aluminum species of 10.
Further, the CHA molecular sieve is an SSZ-13 type zeolite molecular sieve.
The invention also provides a catalyst prepared by the preparation method.
The catalyst can be used for reducing nitrogen oxides into nitrogen under the condition of introducing a reducing agent within the temperature range of 150-550 ℃.
Compared with the prior art, the invention has the beneficial effects that:
after the metal-loaded molecular sieve prepared by the method is subjected to microwave treatment, the catalytic performance of the molecular sieve can be remarkably improved, the temperature window is expanded from the conventional temperature of 250-400 ℃ to the temperature range of 150-550 ℃, and the catalytic efficiency of nitrogen oxides is kept very good even under the condition of low temperature or high temperature.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.
FIG. 1 is a graph showing the catalytic performance of Cu-SSZ-13 samples prepared in example 1 and comparative example 1 of the present invention;
FIG. 2 is a graph of the catalytic performance of Cu-SSZ-13 samples prepared in example 2 and comparative example 2 of the present invention;
FIG. 3 is a graph of the catalytic performance of a Cu-SSZ-13 sample prepared in example 3 of the present application;
FIG. 4 is a graph of the catalytic performance of Cu-SSZ-13 samples prepared in example 4 and comparative example 4 of the present invention;
FIG. 5 is a graph showing the catalytic performance of Cu-SSZ-13, cu-ZSM-5, and Cu-Beta samples prepared in examples 1, 5, and 6 of the present invention;
FIG. 6 is a graph showing the water and sulfur resistance of Cu-SSZ-13 samples prepared in example 1 and comparative example 1 of the present invention;
FIG. 7 is a graph showing the water resistance of Cu-SSZ-13 samples prepared in example 1 and comparative example 1 of the present invention;
FIG. 8 is a graph showing sulfur resistance of Cu-SSZ-13 samples prepared in example 1 and comparative example 1 according to the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below. It will be apparent that the described embodiments are only some, but not all, embodiments of the invention. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the invention, are within the scope of the invention.
The units in weight volume percent are well known to those skilled in the art and refer, for example, to the weight of solute in 100 milliliters of solution.
In the present invention, the concentration unit "M" of the solution represents mol/L.
Nitrogen oxides refer to compounds consisting of only two elements, nitrogen and oxygen, and include various compounds such as nitrous oxide (N) 2 O), nitric Oxide (NO), nitrogen dioxide (NO 2 ) Dinitrogen trioxide (N) 2 O 3 ) Dinitrogen tetroxide (N) 2 O 4 ) And dinitrogen pentoxide (N) 2 O 5 ) Etc. Thus, in the environment, several gas mixtures are exposed, often called nitrate fumes (gases), mainly nitric oxide and nitrogen dioxide, and mainly nitric oxide. Nitrogen oxides all have varying degrees of toxicity.
The term "molecular sieve" is an artificially synthesized hydrated aluminosilicate (zeolite) or natural zeolite having a molecular sieving effect.
The CHA molecular sieve is a small pore molecular sieve due to the special cage-type pore structure.
The microwave is an electromagnetic wave with a frequency of 300 MHz-300 GHz.
The power density of the microwave treatment refers to the microwave power applied per sample to be treated.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. In addition, any methods and materials similar or equivalent to those described herein can be used in the methods of the present invention. The preferred methods and materials described herein are presented for illustrative purposes only.
Most of the existing SCR catalysts have NO at low temperature of 150-250 ℃ and high temperature of 450-550 DEG C x The catalytic activity is to be improved. Different from the catalyst in the prior art, the temperature window of the SCR catalyst is widened by more than two metal modified molecular sieves. The invention provides a preparation method of a wide temperature window SCR catalyst, which is based on a conventional ion exchange or impregnation method to obtain a supported metal/small pore molecular sieve, and adopts a microwave external field treatment technology to perform activation pretreatment and displayThe method for improving the catalytic activity of the catalyst and widening the SCR reaction temperature window comprises the following steps: preparing a metal-loaded CHA molecular sieve; and carrying out microwave treatment on the CHA molecular sieve loaded with the metal to obtain the catalyst.
Compared with the microwave treatment applied in the preparation process of the CHA molecular sieve or the process of loading the Cu metal into the CHA molecular sieve, the catalytic performance of the finally obtained CHA molecular sieve loaded with the Cu metal in a nitrogen oxide reduction system is not obviously changed due to the microwave application. The microwave treatment step is carried out after the metal is loaded on the molecular sieve through the steps of drying, roasting and the like, and the temperature window for selective catalytic reduction of nitrogen oxides is relatively wide.
Specifically: by applying a microwave field to a Cu-loaded CHA molecular sieve, the surface properties of the CHA molecular sieve are affected first, and after microwave irradiation onto the CHA molecular sieve surface, the plugged pores are opened by frequent vibratory collisions of a large number of moving neighboring particles, increasing the porosity and pore volume, thereby increasing the surface area, resulting in an increase in the ion exchange capacity of the CHA molecular sieve. Meanwhile, the dispersion degree of Cu species loaded on the molecular sieve is improved, and accordingly, the adsorption capacity/reactivity of the adsorbent/catalyst is improved.
Further, cu may be selected as the metal.
In certain embodiments, the Cu element is present in the catalyst in an amount of 0.1 to 10.0wt%.
The content of the metal element in the catalyst means a ratio of the mass of the metal element to the mass of the molecular sieve. As the copper content increases, the temperature window T90 of Cu-SSZ-13 (the temperature range where the nitrogen oxide conversion exceeds 90%) shifts from high to low. The copper content directly affects the chemical state of the copper active species in the catalyst, and at low copper content, the copper species is represented by Z 2 The Cu (II) form is preferentially loaded near the six-membered ring, so that excellent high-temperature catalytic activity is realized, and as the copper content increases, copper species enter near the eight-membered ring of the SSZ-13 molecular sieve to form ZCu (II) OH, and the active copper species in the state are beneficial to the selective catalytic reduction of low-temperature nitrogen oxides. Copper content is increased to a certain degree, catalystSurface copper oxide species increase, catalytic oxidation capacity increase, byproducts increase, and NH is not favored 3 -SCR reaction. Considering the actual emission temperature range of the automobile exhaust, the optimal copper content should be controlled to be 0.5-4.5 wt%. (proton acid center (B acid center) formed by framework aluminum atoms on molecular sieves is denoted as Z)
In the preparation process, the microwave treatment conditions are as follows:
and carrying out microwave treatment under the condition that the power density is 1500-3000W/g, wherein the temperature is controlled to be 50-220 ℃ in the microwave treatment process.
In a preferred scheme, the microwave treatment is carried out under the condition that the power density is 1800-2500W/g, and the temperature is controlled to be 60-110 ℃ in the microwave treatment process.
When the CHA molecular sieve loaded with the metal Cu is subjected to microwave treatment, the CHA molecular sieve loaded with the metal Cu is treated in the power range and the temperature range by controlling microwaves, and more moving adjacent particles frequently vibrate and collide to open the blocked holes, so that the ion exchange capacity of the CHA molecular sieve and the dispersion degree of Cu species are further increased. In particular in NH 3 In the system of SCR, the catalyst has better catalytic activity.
The microwave treatment time is generally controlled to be 5 min-90 min; preferably, the microwave treatment time is controlled to be 10-40 min. More preferably, the microwave treatment time is 20-40 min. Treating for 20 min-40 min under the condition of the power density, especially for 30min, under NH 3 In SCR systems, the catalyst activity after microwave treatment is significantly improved compared to the catalyst before the treatment at low temperatures (below 200 ℃, e.g. 150 ℃) or at high temperatures (above 450 ℃, e.g. 500 ℃, 550 ℃).
In certain embodiments, the process gas is continuously introduced during the microwave treatment, e.g., containing O 2 And N 2 The mixed gas is introduced into the reactor or contains N 2 Is a gas of (a) a gas of (b). Alternatively, the flow rate of the process gas is 20-500mL/min. The microwave treatment is carried out in the atmosphere, which is more beneficial to improving the selective catalytic reduction performance of the molecular sieve on nitrogen oxides.
In particular, in microwave treatment, inert gas is used as the treatment gas, e.g. N 2 The treatment gas quantity is 20-500mL/min, and the microwave treatment is accompanied with energy output, so that the oxidation condition of the active component copper can be avoided under the protection of inert gas. The obtained treated Cu-loaded CHA molecular sieve has stronger catalytic performance. The Cu-loaded CHA molecular sieve treated under such conditions is used as a catalyst for nitrogen oxide reduction at low temperatures (e.g., less than 150 ℃) or at high temperatures (greater than 500 ℃) with nitrogen oxide conversion rates of greater than 90%.
More preferably, the amount of the inert gas is 50 to 150mL/min.
In addition, in the present invention, for the specific selection of the CHA-type molecular sieve, it is generally preferable that the ratio of the amount of the silicon element to the amount of the aluminum element in the CHA-type molecular sieve is 10 to 25, for example, the CHA-type molecular sieve may be an SSZ-13-type zeolite molecular sieve, and the SSZ-13 molecular sieve is a micro-porous molecular sieve having a Chabazite (CHA) structure, and has a higher silicon-to-aluminum ratio (i.e., the ratio of the amount of the silicon element to the amount of the aluminum element in the molecular sieve) composition and a cage-like crystal structure with eight-membered ring openings. In certain embodiments, the SSZ-13 type zeolite molecular sieve has a crystallite size between 100nm and 3 μm. The SSZ-13 molecular sieve can be selected from commercial products or homemade SSZ-13 molecular sieve products, so long as the silicon-aluminum ratio is 10-25, preferably 10, and the conditions are met
Compared with the SSZ-13 type molecular sieve before the microwave treatment, the temperature window for selective catalytic reduction of nitrogen oxides is obviously widened after the SSZ-13 type molecular sieve loaded with Cu is subjected to the microwave treatment. Under certain microwave treatment conditions, the selective catalytic reduction of nitrogen oxides can be improved by more than 10% compared with the selective catalytic reduction of nitrogen oxides without microwave treatment at the temperature of below 200 ℃ or above 450 ℃.
The invention also provides a preparation method of the CHA molecular sieve loaded with metal, which comprises the following steps:
and mixing the soluble salt solution of the metal element with the CHA molecular sieve, and roasting the solid matters obtained after the mixing step at the temperature of 350-600 ℃ to obtain the metal-loaded CHA molecular sieve.
The soluble salt solution of the metal element may be one or a mixture of nitrate, acetate or chloride. The metal element includes Cu element.
When the soluble salt solution of the metal element is mixed with the CHA molecular sieve, the subsequent process steps can be determined according to the dosage relation of Cu and the CHA molecular sieve in the soluble salt solution.
The mass ratio of the CHA molecular sieve to Cu in the soluble salt solution is 10-1000. Preferably, the mass ratio of the SSZ-13 molecular sieve to the mixed liquor is 1/10.
The concentration of solute (e.g., copper nitrate) in the soluble salt solution is determined by the metal content to be supported.
When the mass ratio of the CHA molecular sieve to copper in the salt solution exceeds 100, the metal loading process adopts an impregnation method, and the specific preparation method comprises the following steps: and mixing the soluble salt solution of the metal element with the CHA molecular sieve, drying the obtained mixture, and roasting at the temperature of 350-600 ℃ to obtain the metal-loaded CHA molecular sieve.
When the mass ratio of the CHA molecular sieve to copper in the salt solution is 10-100, the metal loading process adopts an ion exchange method, and the specific preparation method comprises the following steps: mixing a soluble salt solution of a metal element with the CHA molecular sieve, filtering the obtained mixture, drying the obtained solid substance, and roasting at the temperature of 350-600 ℃ to obtain the metal-loaded CHA molecular sieve.
The present invention preferably employs an ion exchange process to support the metal on the CHA molecular sieve. The CHA molecular sieve is preferably an SSZ-13 molecular sieve.
When the SSZ-13 molecular sieve loaded with Cu is prepared, the roasting temperature is controlled to be 450-550 ℃. Preferably, the temperature rising rate during roasting is controlled to be 2-5 ℃/min.
Under the roasting condition, the morphology of Cu species can be maintained, and the original framework of the molecular sieve can be maintained. After microwave treatment under certain conditions, the catalyst performance is better in an SCR reaction system for removing nitrogen oxides.
In certain embodiments, the temperature of the soluble salt solution of the metal element and the SSZ-13 molecular sieve is controlled to be between room temperature and 80 ℃. Preferably, the temperature during mixing is controlled at 60-80 ℃.
In the nitrogen oxide SCR reaction system, the CHA molecular sieve treated by the microwave not only has remarkably improved catalytic performance at low temperature or high temperature, but also maintains good water resistance and sulfur resistance.
On the other hand, the catalyst is applied to the reaction of catalyzing and reducing the nitrogen oxides, wherein the nitrogen oxides are reduced under the action of the catalyst under the condition that the reaction temperature is 150-550 ℃ and a reducing agent is introduced.
The reducing agent can be ammonia, CO, or the like. Preferably, ammonia is used as the reducing gas.
Preferably, the reaction temperature is 150 to 200 ℃, or 450 to 550 ℃. In this high or low temperature range, shows better catalytic performance than the prior art catalysts.
More preferably, the reaction temperature is about 150 ℃, or 500 ℃ to 550 ℃, and the catalyst performance is higher in amplitude.
The microwave treated CHA molecular sieves of the present invention and catalytic performance in SCR systems for nitrogen oxide removal are further described below in conjunction with specific examples.
In the following examples, SCR activity tests were performed on the resulting catalysts, and specific experimental methods were:
NH 3 SCR activity test specific operations are as follows: catalyst materials (40, mg) prepared in examples 1 to 6 and comparative examples 1 to 2 were weighed, respectively, and put into a quartz tube of a reaction furnace. Setting the total flow of the gas to be 100mL/min and N 2 Is balance gas; setting the inlet concentration of the reaction gas to be NO 500ppm and NH 3 500ppm、N 2 85%、O 2 500ppm. Setting the temperature of a reaction furnace, carrying out programmed heating at a heating rate of 5 ℃/min, detecting the concentration of an air outlet at intervals of 50 ℃ within a temperature range of 150-550 ℃, and passing the initial NO x Concentration comparison yields NO conversion.
Example 1
10g of SSZ-13 molecular sieve (Si/Al=10), 100g of deionized water and 0.63g of solid (CH) 3 COO) 2 Cu•H 2 O was mixed and stirred in a beaker, and ion-exchanged in a water bath at 80℃for 5 hours (rotation speed 450 r/min). Filtering, washing to neutrality, and oven drying at 100deg.C for 12 hr. And (5) after suction filtration and drying, repeating exchange once. And (3) heating the dried sample to 550 ℃ at a speed of 5 ℃/min, roasting for 4 hours to obtain a Cu-SSZ-13 sample, and tabletting (40-60 meshes).
At N 2 Setting the microwave power to 250W in the (flow rate of 100 mL/min) atmosphere, after the temperature rises to 50 ℃, placing 0.1g of the prepared Cu-SSZ-13 material into a microwave oven, controlling the temperature within the range of 50-220 ℃, and performing activation treatment for 30min to perform SCR activity test.
Example 2
10g of SSZ-13 molecular sieve (Si/Al=10), 100g of deionized water and 0.63g of solid (CH) 3 COO) 2 Cu•H 2 O was mixed and stirred in a beaker, and ion-exchanged in a water bath at 80℃for 5 hours (rotation speed 450 r/min). Filtering, washing to neutrality, and oven drying at 100deg.C for 12 hr. And (5) after suction filtration and drying, repeating exchange once. And roasting the dried sample at 550 ℃ for 4 hours to obtain a Cu-SSZ-13 sample, and tabletting (40-60 meshes).
At O 2 O with a ratio of 10 vol% 2 /N 2 Setting the microwave power to 250W in the mixed gas (flow 100 mL/min) atmosphere, after the temperature rises to 50 ℃, placing 0.1g of the prepared Cu-SSZ-13 material into a microwave oven, controlling the temperature within the range of 50-220 ℃, and performing activation treatment for 30min to perform SCR activity test.
Example 3
10g of SSZ-13 molecular sieve (Si/Al=10), 100g of deionized water and 0.63g of solid (CH) 3 COO) 2 Cu•H 2 O was mixed and stirred in a beaker, and ion-exchanged in a water bath at 80℃for 5 hours (rotation speed 450 r/min). Filtering, washing to neutrality, and oven drying at 100deg.C for 12 hr. And (5) after suction filtration and drying, repeating exchange once. And roasting the dried sample at 550 ℃ for 4 hours to obtain a Cu-SSZ-13 sample, and tabletting (40-60 meshes).
At N 2 (flow rate 100 mL/min) the microwave power was set to 100W in the atmosphere, and after the temperature was raised to 50 ℃, 0.1g of the obtained Cu-SS was obtainedAnd placing the Z-13 material in a microwave oven, controlling the temperature within the range of 50-220 ℃, and performing activation treatment for 30min to perform SCR activity test.
Example 4
10g of SSZ-13 molecular sieve (Si/Al=10), 100g of deionized water and 0.63g of solid (CH) 3 COO) 2 Cu•H 2 O was mixed and stirred in a beaker, and ion-exchanged in a water bath at 80℃for 5 hours (rotation speed 450 r/min). Filtering, washing to neutrality, and oven drying at 100deg.C for 12 hr. And (5) after suction filtration and drying, repeating exchange once. And roasting the dried sample at 550 ℃ for 4 hours to obtain a Cu-SSZ-13 sample, and tabletting (40-60 meshes).
At N 2 Setting the microwave power to 250W in the (flow rate of 100 mL/min) atmosphere, after the temperature rises to 50 ℃, placing 0.1g of the prepared Cu-SSZ-13 material into a microwave oven, controlling the temperature within the range of 50-220 ℃, and performing activation treatment for 15min to perform SCR activity test.
Example 5
10g of ZSM-5 molecular sieve (Si/Al=10.5) was admixed with 100g of deionized water and 0.63g of solid (CH 3 COO) 2 Cu•H 2 O was mixed and stirred in a beaker, and ion-exchanged in a water bath at 80℃for 5 hours (rotation speed 450 r/min). Filtering, washing to neutrality, and oven drying at 100deg.C for 12 hr. And (5) after suction filtration and drying, repeating exchange once. And roasting the dried sample at 550 ℃ for 4 hours to obtain a Cu-ZSM-5 sample, and tabletting (40-60 meshes).
At N 2 Setting the microwave power to 250W in the (flow rate of 100 mL/min) atmosphere, after the temperature rises to 50 ℃, placing 0.1g of the prepared Cu-ZSM-5 material into a microwave oven, controlling the temperature within the range of 50-220 ℃, and performing activation treatment for 30min to perform SCR activity test.
Example 6
10g of Beta molecular sieve (Si/Al=12.5) was combined with 100g of deionized water and 0.63g of solid (CH 3 COO) 2 Cu•H 2 O was mixed and stirred in a beaker, and ion-exchanged in a water bath at 80℃for 5 hours (rotation speed 450 r/min). Filtering, washing to neutrality, and oven drying at 100deg.C for 12 hr. And (5) after suction filtration and drying, repeating exchange once. Dried sample at 55Roasting for 4 hours at 0 ℃ to obtain a Cu-Beta sample, and tabletting (40-60 meshes).
At N 2 Setting the microwave power to 250W in the (flow rate of 100 mL/min) atmosphere, after the temperature rises to 50 ℃, placing 0.1g of the prepared Cu-Beta material into a microwave oven, controlling the temperature within the range of 50-220 ℃, and performing activation treatment for 30min to perform SCR activity test.
Comparative example 1
Other raw material ratios and process flows of the embodiment are the same as those of the embodiment 1, except that: the obtained Cu-SSZ-13 material sample is directly subjected to SCR activity test without microwave treatment.
Comparative example 2
10g of SSZ-13 molecular sieve (Si/Al=10), 100g of deionized water and 0.63g of solid (CH) 3 COO) 2 Cu•H 2 O is mixed and stirred in a beaker, water bath ion exchange is carried out for 5 hours (the rotating speed is 450 r/min) at 80 ℃, and the mixture is treated with (CH) in an SSZ-13 molecular sieve 3 COO) 2 Cu•H 2 Washing the O ion exchanged solution, placing the beaker with the mixed solution directly in a microwave oven, and adding the mixed solution into O 2 O with a ratio of 10 vol% 2 /N 2 And (3) in the atmosphere of mixed gas (flow 100 mL/min), drying for 30min under the power of 250W to obtain a dry Cu-SSZ-13 molecular sieve solid sample, tabletting (40-60 meshes), and then carrying out SCR activity test.
Comparative example 3
The other raw material ratios and the process flow of this comparative example were the same as in example 1, except that the microwave treatment was applied to the 100 ℃ baking process, and the Cu-SSZ-13 material sample obtained after baking was not subjected to the microwave treatment. The catalyst obtained in this comparative example was subjected to SCR activity test, and its catalytic activity was comparable to that of comparative example 1.
Comparative example 4
Other raw material ratios and process flows of the comparative example are the same as those of example 4, except that the obtained Cu-SSZ-13 material sample was directly subjected to SCR activity test without microwave treatment.
The SCR activity test results of examples 1 to 6 and comparative examples 1 to 4 are shown in FIGS. 1 to 5.
From the comparison of example 1 and comparative example 1 and the comparison of example 4 and comparative example 4, it is known whether the microwave treatment has a significant influence on the performance of the catalyst during the preparation of the catalyst.
From a comparison of example 2 and comparative example 2 and a comparison of example 1 and comparative example 3, it is evident that the step of microwave treatment application has a significant effect on the performance of the catalyst.
As can be seen from comparison of examples 1-4, the selection of the process gas, the power of the microwaves and the time all have significant effects on the performance of the catalyst, wherein the optimal scheme is example 1.
From a comparison of example 1 and examples 5 and 6, it is evident that the type of molecular sieve, i.e. the ratio of the amounts of substances of elemental silicon to elemental aluminum in the molecular sieve, has a significant effect on the performance of the final catalyst, wherein the optimal solution is example 1.
Experimental example
The test example is to test sulfur resistance and water resistance of the Cu-SSZ-13 samples prepared in the example 1 and the comparative example 1.
(1) Sulfur resistance test conditions: total gas flow 100mL/min, 5 vol% O 2 ，500ppm NO，500ppm NH 3 ，150 ppm SO 2 The balance gas is N 2 . At a reaction temperature of 300 ℃, 150 ppm SO was introduced after testing the initial activity without sulfur 2 Sample activity was measured for 22 hours in succession. The experimental results are shown in fig. 8.
(2) Water resistance test: total gas flow 100mL/min, 5 vol% O 2 ，500ppm NO，500ppm NH 3 ，5 vol% H 2 O, balance gas N 2 . At a reaction temperature of 300 ℃, after testing the initial activity without water, 5 vol% H was introduced 2 O was tested for sample activity for 22 hours in succession. The experimental results are shown in fig. 7.
(3) Sulfur resistance water resistance test: total gas flow 100mL/min, 5 vol% O 2 ，500ppm NO，500ppm NH 3 ，5 vol% H 2 O，150 ppm SO 2 The balance gas is N 2 . At a reaction temperature of 300 ℃, after testing the initial activity without introducing sulfur and water,introducing 150 ppm SO 2 5 vol% H 2 O is continuously detected for 10 hours to detect the activity of the sample, and then SO in the reaction gas is cut off 2 And H 2 O gas for 3 hours, and test for performance recovery. The experimental results are shown in fig. 6.
From the aspect of sulfur resistance and water resistance, the catalyst subjected to microwave treatment can protect good catalytic activity in the SCR system in the atmosphere of sulfur and water at the same time, and has sulfur resistance and water resistance. And the catalytic performance can be improved compared with the catalyst which is not treated by microwaves.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present application. As used in this specification, the terms "a," "an," "the," and/or "the" are not intended to be limiting, but rather are to be construed as covering the singular and the plural, unless the context clearly dictates otherwise. The terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method or apparatus comprising such elements.
It should also be noted that the positional or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the positional or positional relationship shown in the drawings, are merely for convenience of describing the present invention and simplifying the description, and do not indicate or imply that the apparatus or element in question must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention. Unless specifically stated or limited otherwise, the terms "mounted," "connected," and the like are to be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the essence of the corresponding technical solutions from the technical solutions of the embodiments of the present invention.
Claims (3)
1. The preparation method of the wide temperature window SCR catalyst is characterized by comprising the following steps of:
10g of SSZ-13 molecular sieve with Si/Al=10, 100g of deionized water and 0.63g of solid (CH 3 COO) 2 Cu•H 2 O is mixed and stirred in a beaker, water bath ion exchange is carried out for 5 hours at the temperature of 80 ℃ and the rotating speed of 450r/min, suction filtration is carried out, washing is carried out to neutrality, drying is carried out for 12 hours in a baking oven at the temperature of 100 ℃, suction filtration and drying are carried out, repeated exchange is carried out once, the dried sample is heated to 550 ℃ at the speed of 5 ℃/min and baked for 4 hours, a Cu-SSZ-13 sample is obtained, and tabletting is carried out to 40-60 meshes;
at N 2 Setting the microwave power to 250W in the atmosphere with the flow of 100mL/min, after the temperature is raised to 50 ℃, placing 0.1g of the prepared Cu-SSZ-13 material into a microwave oven, controlling the temperature within the range of 50-220 ℃, and performing activation treatment for 30min to perform SCR activity test.
2. A catalyst prepared by the preparation process of claim 1.
3. The catalyst of claim 2 or the catalyst prepared by the preparation method of claim 1, which is used for reducing nitrogen oxides into nitrogen under the condition of introducing a reducing agent at the temperature of 150-550 ℃.
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| KR970014833A (en) * | 1995-09-05 | 1997-04-28 | 강박광 | Method for preparing a highly dispersed mixed metal oxide supported catalyst |
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| WO2013097677A1 (en) * | 2011-12-30 | 2013-07-04 | 湘潭大学 | Microwave catalyst and preparation process and use thereof |
| WO2015051502A1 (en) * | 2013-10-09 | 2015-04-16 | 浙江大学 | Method for regenerating scr denitration catalyst assisted by microwaves and device therefor |
| CN117019214A (en) * | 2023-08-10 | 2023-11-10 | 天津工业大学 | Preparation method of catalyst for improving denitration performance of metal modified SSZ-13 |
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| KR970014833A (en) * | 1995-09-05 | 1997-04-28 | 강박광 | Method for preparing a highly dispersed mixed metal oxide supported catalyst |
| WO2013097677A1 (en) * | 2011-12-30 | 2013-07-04 | 湘潭大学 | Microwave catalyst and preparation process and use thereof |
| CN103127950A (en) * | 2013-02-22 | 2013-06-05 | 岳阳怡天化工有限公司 | Cu-ZSM catalyst, and preparation method and application thereof |
| WO2015051502A1 (en) * | 2013-10-09 | 2015-04-16 | 浙江大学 | Method for regenerating scr denitration catalyst assisted by microwaves and device therefor |
| CN117019214A (en) * | 2023-08-10 | 2023-11-10 | 天津工业大学 | Preparation method of catalyst for improving denitration performance of metal modified SSZ-13 |
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