CN114054075B - Preparation method of composite modified zeolite molecular sieve catalyst - Google Patents
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- 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
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- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/86—Catalytic processes
- B01D53/8621—Removing nitrogen compounds
- B01D53/8625—Nitrogen oxides
- B01D53/8628—Processes characterised by a specific catalyst
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- B01J29/00—Catalysts comprising molecular sieves
- B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
- B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
- B01J29/40—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the pentasil type, e.g. types ZSM-5, ZSM-8 or ZSM-11, as exemplified by patent documents US3702886, GB1334243 and US3709979, respectively
- B01J29/42—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the pentasil type, e.g. types ZSM-5, ZSM-8 or ZSM-11, as exemplified by patent documents US3702886, GB1334243 and US3709979, respectively containing iron group metals, noble metals or copper
- B01J29/46—Iron group metals or copper
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- 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
- B01J29/7615—Zeolite Beta
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- B01J2229/00—Aspects of molecular sieve catalysts not covered by B01J29/00
- B01J2229/10—After treatment, characterised by the effect to be obtained
- B01J2229/18—After treatment, characterised by the effect to be obtained to introduce other elements into or onto the molecular sieve itself
- B01J2229/186—After treatment, characterised by the effect to be obtained to introduce other elements into or onto the molecular sieve itself not in framework positions
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- Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
Abstract
The application discloses a preparation method of a composite modified zeolite molecular sieve catalyst, which is characterized in that a carrier zeolite molecular sieve after dehydration pretreatment is placed in a gradient modified solution for multi-step impregnation. The preparation method can regulate and control the metal loading and species so as to achieve the aim of regulating the quantity and the existence state of the catalytic active center. The obtained composite modified zeolite molecular sieve catalyst has the characteristics of high catalytic activity, wide temperature window and high thermal stability, and has important application value in the field of automobile tail gas denitration.
Description
Technical Field
The application relates to a preparation method of a composite modified zeolite molecular sieve catalyst, and belongs to the technical field of denitration catalysts.
Background
Nitrogen Oxides (NO) x ) Is an important substance polluting the atmosphere, and the emission of a large amount of the important substance can cause serious environmental problems such as acid rain, photochemical smog, ozone layer damage and the like. NO in atmosphere x Mainly from emissions from stationary and mobile sources. Stationary sources mainly include power plants, cement plants, and other industrial emissions, and mobile sources are mainly motor vehicles. Compared with the mobile source of the motor vehicle, the fixed source dyeing source (coal-fired power plant) is relatively concentrated, and NO is controlled under the macroscopic regulation of the national policy for several years x The control effect is obvious, so that the control of the mobile source of the motor vehicle becomes a key link of the atmospheric pollution control in China. "annual report of environmental management of vehicles in 2016 China" shows that China has already been in ChinaSeven years continue to become the first country of world motor vehicle production and marketing, and the quantity of motor vehicles kept in China continues to increase. The holding capacity of the national motor vehicles is increased from 19006.2 to 26002.5 ten thousand from 2010 to 2015, and the annual growth is 6.5%. This also brings about an increase in pollutant emissions, up to 584.9 thousand tons of nitrogen oxides in 2015 national automotive pollutant emissions, where diesel NO x The emission sharing rate was 69%. In recent years, with the increasing shortage of global petroleum resources and the increasing of greenhouse gas effect, there is a trend of diesel oil production of motor vehicles at home and abroad. Compared with gasoline vehicles, the diesel vehicle adopts the lean burn technology, has high efficiency and can greatly reduce CO 2 Is used for the discharge amount of the fuel. Under the promotion of energy conservation and emission reduction policies, diesel engines adopting lean burn technology are increasingly receiving widespread attention. It is expected that the occupancy of Chinese diesel cars will reach over 30% by 2020. Urban air pollution in China is gradually changed from soot type pollution to motor vehicle tail gas type pollution.
Currently, NO x Selective Catalytic Reduction (SCR) technology is an important technology for removing NO from diesel vehicle exhaust x Is a commercial technology of (a). The first generation of industrialized diesel vehicle tail gas catalyst is WO 3 Or MoO 3 Doped V 2 O 5 /TiO 2 The main active center of the catalyst is a toxic vanadium element, and the catalyst is easy to evaporate in the use process to cause environmental pollution. In addition, the catalyst generates N under the conditions of narrow temperature window and high temperature 2 O byproducts, etc., and cannot be used in combination with diesel particulate traps. For the above reasons, countries such as europe and america and japan have prohibited the use of this catalyst in diesel vehicle exhaust systems. In recent years, the emission standards of motor vehicle exhaust gas have been increased in China, and five standards (Euro V) of motor vehicles have been implemented since 1 st 2017, and recently, environmental protection units have issued "letters of opinion about the requirements for national environmental protection standards of compression ignition, gas fuel ignition engines and exhaust pollutant emission limits of automobiles and measurement methods (Chinese sixth stage) (requirements for opinion draft)" and "six standards (Euro VI) of diesel vehicles are about to be implemented. Therefore, the environment-friendly and high-efficiency diesel vehicle tail gas NO is developed x Removal catalystThe chemical agent has important theoretical and practical significance.
Environment-friendly NH 3 The SCR molecular sieve based catalyst has the advantages of high catalytic activity, wide temperature window, high thermal stability and high space velocity treatment capability, and is widely focused and applied to diesel vehicle exhaust gas treatment systems in europe, the united states, japan and other countries. Molecular sieve based NH 3 The development of SCR catalysts has undergone the history of MFI, BEA, FAU, MOR to CHA molecular sieves of different topologies as supports. In recent years, cu modified catalysts having SSZ-13 zeolite molecular sieves with CHA topology as supports have received widespread attention. The studies found that different Cu species (Cu + ，Cu 2+ CuOcluster) plays a respective catalytic role at different temperatures, which is also why copper-modified catalysts have a broad activity temperature window. However, in the catalyst preparation process, the proportion and distribution state of each copper species are difficult to control, so that the activity of the Cu/SSZ-13 catalyst has large difference. In the preparation process of the catalyst, how to effectively regulate the proportion of copper species to obtain the catalyst with high catalytic activity, wide temperature window and high thermal stability is a technical difficulty. Therefore, a new preparation method of the composite modified zeolite molecular sieve catalyst with high catalytic activity, wide temperature window and high thermal stability is still needed to be developed.
Disclosure of Invention
Aiming at the problems existing in the preparation of the existing automobile exhaust denitration catalyst, namely: the catalytically active central Cu species (Cu in the catalyst + ，Cu 2+ CuO clusters) ratio and distribution state are difficult to control, so that the activity difference of the catalyst is larger. The catalyst is obtained from 200 to 400 ℃ and NO x The conversion rate reaches 99%,400-500 ℃, NO x The conversion rate reaches more than 90 percent. After the reaction temperature is higher than 500 ℃, the catalytic performance is slightly reduced, butNO x Conversion is still>80％。
According to one aspect of the application, a preparation method of a composite modified zeolite molecular sieve catalyst is provided, and the method utilizes the gradient change of the concentration of a modifying solution in the modification process to regulate and control the metal loading and species so as to achieve the quantity and the existence state of the prepared catalytic active center, so that the composite modified zeolite molecular sieve catalyst with high catalytic activity, wide temperature window and high thermal stability is obtained.
A method for preparing a composite modified zeolite molecular sieve catalyst, which at least comprises the following steps:
(1) Carrying out dehydration pretreatment on a carrier zeolite molecular sieve;
(2) Placing the carrier zeolite molecular sieve subjected to dehydration pretreatment in a copper salt aqueous solution I, impregnating the carrier zeolite molecular sieve with the copper salt aqueous solution I, and filtering to obtain a solid I;
the concentration of the copper salt aqueous solution I is 1-10M;
(3) Placing the solid I obtained in the step (2) into a copper salt water solution II, dipping the II, and filtering to obtain a solid II;
the concentration of the copper salt aqueous solution II is 0.1-1.0M;
(4) Placing the solid II obtained in the step (3) into a copper salt water solution III, adding ferric salt and/or rare earth metal salt, dipping the III, and filtering to obtain a solid III;
the concentration of the copper salt aqueous solution III is 0.01-0.10M;
(5) And (3) drying and roasting the solid III obtained in the step (4) to obtain the composite modified zeolite molecular sieve catalyst.
Optionally, in the step (2), the concentration of the copper salt aqueous solution I is 5 to 10M.
Optionally, in the step (2), the concentration of the copper salt aqueous solution I is 2 to 8M.
Optionally, in step (2), the upper limit of the concentration of the copper salt aqueous solution I is selected from 2M, 3M, 4M, 5M, 6M, 7M, 7.5M, 8M, 9M or 10M; the lower limit is selected from 9M, 8M, 7.5M, 7M, 6M, 5M, 4M, 3M, 2M or 1M.
Optionally, in the step (3), the concentration of the copper salt aqueous solution II is 0.5-1.0M.
Optionally, in the step (3), the concentration of the copper salt aqueous solution II is 0.2-0.8M.
Optionally, in step (3), the upper limit of the concentration of the copper salt aqueous solution I is selected from 0.2M, 0.3M, 0.4M, 0.5M, 0.6M, 0.7M, 0.75M, 0.8M, 0.9M or 1.0M; the lower limit is selected from 0.9M, 0.8M, 0.75M, 0.7M, 0.6M, 0.5M, 0.4M, 0.3M, 0.2M or 0.1M.
Optionally, in the step (4), the concentration of the copper salt aqueous solution II is 0.05-0.10M.
Optionally, in the step (4), the concentration of the copper salt aqueous solution II is 0.02-0.08M.
Optionally, in step (4), the upper limit of the concentration of the copper salt aqueous solution I is selected from 0.02M, 0.03M, 0.04M, 0.05M, 0.06M, 0.07M, 0.075M, 0.08M, 0.09M or 0.10M; the lower limit is selected from 0.09M, 0.08M, 0.075M, 0.07M, 0.06M, 0.05M, 0.04M, 0.03M, 0.02M, or 0.01M.
Optionally, the carrier zeolite molecular sieve is selected from at least one of CHA-type zeolite molecular sieve, MFI-type zeolite molecular sieve, BEA-type zeolite molecular sieve.
Optionally, the CHA zeolite molecular sieve is selected from at least one of SSZ-13 zeolite molecular sieve, SAPO zeolite molecular sieve.
Optionally, the MFI-type zeolite molecular sieve is selected from at least one of ZSM-5 zeolite molecular sieve and S-1 zeolite molecular sieve.
Optionally, the BEA-type zeolite molecular sieve is selected from Beta zeolite molecular sieves.
Optionally, the copper salt in the copper salt aqueous solution is at least one selected from copper nitrate, copper acetate and copper sulfate.
Optionally, in step (4), the iron salt is selected from at least one of ferric nitrate, ferric sulfate, ferric chloride.
Optionally, the dosage of the ferric salt is 0.3-10% of the mass of the carrier zeolite molecular sieve;
wherein the amount of the iron salt is calculated by the mass of the Fe element contained therein.
Optionally, the amount of the iron salt is such that the upper limit of the percentage by mass of the supported zeolite molecular sieve is selected from 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%; the lower limit is selected from 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5% or 0.3%.
Optionally, in step (4), the rare earth metal of the rare earth metal salt is selected from at least one of La, ce, pr, nb.
Optionally, the rare earth metal salt is used in an amount of 0.3 to 10 percent of the mass of the carrier zeolite molecular sieve;
wherein the amount of the rare earth metal salt is calculated based on the mass of the rare earth metal element contained therein.
Optionally, the rare earth metal salt is used in an amount such that the upper limit of the percentage by mass of the carrier zeolite molecular sieve is selected from 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%; the lower limit is selected from 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5% or 0.3%.
Optionally, the rare earth metal salt is selected from at least one of nitrate, sulfate, chloride, carbonate, acetate, oxalate of rare earth metal.
Optionally, in step (2), the conditions of impregnation I are: stirring at 40-80 deg.c for 2-20 hr.
Optionally, in step (3), the conditions of impregnation II are: stirring at 40-80 deg.c for 2-20 hr.
Optionally, in step (4), the conditions of impregnation III are: stirring at 40-80 deg.c for 2-20 hr.
In this application, the impregnation conditions of the individual steps are independent of each other.
Optionally, in the composite modified zeolite molecular sieve catalyst, the loading of Cu element is 1-10wt% and the loading of the multi-element metal element is 0.1-5wt%;
wherein the multi-element metal element refers to iron and/or rare earth metal element.
According to yet another aspect of the present application, a denitration catalyst is provided.
A denitration catalyst comprises at least one of the composite modified zeolite molecular sieve catalysts prepared by the preparation method of the composite modified zeolite molecular sieve catalyst.
According to a further aspect of the present application, there is provided the use of the above denitration catalyst for denitration of automobile exhaust.
The catalyst obtained by the method has different Cu species (Cu + ，Cu 2+ CuO clusters) have reasonable existence state and quantity distribution, play respective catalytic roles at different temperatures, and the particle size of the metal oxide is moderate due to the existence of the composite metal, especially in a high-temperature region, so that the phenomenon of rapid reduction of high-temperature activity caused by metal agglomeration is inhibited. Reaction conditions: catalyst 1g (20-40 mesh), [ NO ]]＝[NH 3 ]＝500ppm，[O 2 ]=5%, he as carrier gas, ghsv=126000h -1 From 200 to 400 ℃, NO x The conversion rate reaches 99%,400-500 ℃, NO x The conversion rate reaches more than 90 percent. After the reaction temperature is higher than 500 ℃, the catalytic performance is slightly reduced, but NO x Conversion is still>80%. The composite modified zeolite molecular sieve catalyst has the characteristics of high catalytic activity, wide temperature window and high thermal stability.
In this application, "room temperature" refers to 25 ℃.
In this application, unless otherwise indicated, numerical ranges refer to any value within the range and include the endpoints.
The beneficial effects that this application can produce include:
according to the preparation method of the composite modified zeolite molecular sieve catalyst, the composite modified Cu, fe and rare earth metal elements are impregnated, and the concentration gradient change of the modifying liquid is utilized in the preparation process to effectively regulate and control the metal loading and species, so that the purposes of regulating the number and the existence state of catalytic active centers are achieved, and the composite modified zeolite molecular sieve catalyst with high catalytic activity, wide temperature window and high thermal stability is obtained. Solves the problems that the traditional single-concentration impregnation modification method can lead to uneven distribution of copper species in catalytic active centers, insufficient quantity of ionic active centers or larger metal oxide particles, and the phenomenon of insufficient low-temperature activity or too fast high-temperature activity reduction, etc. The composite modified zeolite molecular sieve catalyst has wide application prospect in the field of automobile exhaust denitration when being used as a denitration catalyst.
Drawings
Fig. 1 is a Transmission Electron Microscope (TEM) test chart of the catalyst of example 1 and comparative example 1, in which fig. 1a is a test chart of sample 1# and fig. 1b is a test chart of sample d1#.
Fig. 2 is a graph showing the performance test of the catalyst denitration reaction.
Detailed Description
The present application is described in detail below with reference to examples, but the present application is not limited to these examples.
Unless otherwise indicated, all starting materials in the examples of the present application were purchased commercially. Unless otherwise indicated, the analytical methods in the examples employed both conventional settings of the instrument and conventional analytical methods.
Wherein the SSZ-13 zeolite molecular sieve is purchased from the company of Qwanda chemical technology.
The analytical method in the examples of the present application is as follows:
the loading of the metal in the catalyst is tested by an X-ray fluorescence spectrum (X-ray Fluorescence Spectromete, XRF for short) analysis method, and the analysis and test instrument is a BrookSRS 3400 spectrometer.
The particles of the metal in the catalyst are observed by a transmission electron microscope (Transmission Electron Microscope, TEM for short), and the analysis and test instrument is a Philips-FEI company Tecnai F30 field emission transmission electron microscope.
The denitration performance of the catalyst is evaluated by the following method: catalyst 1g (20-40 mesh), [ NO ]]＝[NH 3 ]＝500ppm，[O 2 ]=5%, he as carrier gas, ghsv=126000h -1 。
Wherein GHSV is an abbreviation for gas hourly space velocity, i.e.: gas hourly space velocity.
Wherein NO x Conversion= (1- [ NO] An outlet /[NO] An inlet )╳100％
In the present application, the conventional drying or calcining method is adopted for the dehydration pretreatment of the zeolite molecular sieve, and in the examples, the dehydration pretreatment of the zeolite molecular sieve is carried out according to the following method: the catalyst was placed in a muffle furnace and calcined at 600 c for 5 hours at room temperature for 2 hours.
Example 1
10g of SSZ-13 zeolite molecular sieve after dehydration pretreatment is put into 8M copper nitrate solution, stirred for 10h at 50 ℃, and the obtained solid is filtered. The solid was then put into a 0.8M copper nitrate solution, stirred at 50℃for 10 hours, and filtered to give a solid. The solid was then put into a 0.08M copper nitrate solution, and 0.2g of iron nitrate and 0.34g of cerium nitrate were added thereto, stirred at 50℃for 10 hours, and filtered to obtain a solid. Drying and roasting the solid to obtain the composite modified zeolite molecular sieve catalyst, which is marked as sample No. 1.
Example 2
10g of SSZ-13 zeolite molecular sieve after dehydration pretreatment is put into 5M copper acetate solution, stirred for 10h at 50 ℃, and the obtained solid is filtered. The solid was then put into a 0.5M copper acetate solution, stirred at 50℃for 10 hours, and filtered to give a solid. The solid was then put into a 0.05M copper acetate solution, and 0.2g of iron nitrate and 0.34g of cerium nitrate were added thereto, stirred at 50℃for 10 hours, and filtered to obtain a solid. Drying and roasting the solid to obtain the composite modified zeolite molecular sieve catalyst, which is marked as sample No. 2.
Example 3
10g of SSZ-13 zeolite molecular sieve after dehydration pretreatment is put into 5M copper acetate solution, stirred for 10h at 50 ℃, and the obtained solid is filtered. The solid was then put into a 0.5M copper acetate solution, stirred at 50℃for 10 hours, and filtered to give a solid. The solid was then put into a 0.05M copper acetate solution, and 0.2g of iron nitrate and 0.28g of lanthanum nitrate were added thereto, stirred at 50℃for 10 hours, and filtered to obtain a solid. Drying and roasting the solid to obtain the composite modified zeolite molecular sieve catalyst, which is marked as sample No. 3.
Example 4
10g of SSZ-13 zeolite molecular sieve after dehydration pretreatment was put into 7.5M copper sulfate solution, stirred at 60℃for 10 hours, and the resulting solid was filtered. The solid was then put into a 0.75M copper sulfate solution, stirred at 60℃for 10 hours, and filtered to give a solid. The solid was then placed in a 0.075M copper sulfate solution, 0.2g ferric nitrate was added, stirred at 60℃for 10 hours, and filtered to give a solid. Drying and roasting the solid to obtain the composite modified zeolite molecular sieve catalyst, which is marked as sample No. 4.
Example 5
10g of the dried SSZ-13 zeolite molecular sieve was placed in a 7.5M copper sulfate solution, stirred at 60℃for 10 hours, and the resulting solid was filtered. The solid was then put into a 0.75M copper sulfate solution, stirred at 60℃for 10 hours, and filtered to give a solid. The solid was then placed in a 0.075M copper sulfate solution, 0.51g praseodymium nitrate was added, and the mixture was stirred at 60℃for 10 hours, and the mixture was filtered to obtain a solid. Drying and roasting the solid to obtain the composite modified zeolite molecular sieve catalyst, which is marked as sample No. 5.
Example 6
10g of the dehydrated and pretreated zeolite Beta molecular sieve is placed in 2M copper nitrate solution, stirred for 10 hours at 60 ℃, and the obtained solid is filtered. The solid was then put into a 0.2M copper nitrate solution, stirred at 60℃for 10 hours, and filtered to give a solid. The solid was then put into a 0.02M copper nitrate solution, and 0.2g of iron nitrate and 0.34g of cerium nitrate were added thereto, stirred at 60℃for 10 hours, and filtered to obtain a solid. Drying and roasting the solid to obtain the composite modified zeolite molecular sieve catalyst, which is marked as sample No. 6.
Example 7
10g of the ZSM-5 zeolite molecular sieve after dehydration pretreatment is put into a 3M copper acetate solution, stirred for 10 hours at 60 ℃, and the obtained solid is filtered. The solid was then put into a 0.3M copper acetate solution, stirred at 60℃for 10 hours, and filtered to give a solid. The solid was then put into a 0.03M copper acetate solution, and 0.2g of iron nitrate and 0.34g of cerium nitrate were added thereto, stirred at 60℃for 10 hours, and filtered to obtain a solid. Drying and roasting the solid to obtain the composite modified zeolite molecular sieve catalyst, which is marked as sample No. 7.
Comparative example 1
10g of SSZ-13 zeolite molecular sieve after dehydration pretreatment is put into 8M copper acetate solution, 0.2g of ferric nitrate and 0.34g of cerium nitrate are added, and the mixture is stirred for 10 hours at 50 ℃ and filtered to obtain solid. Drying and roasting the solid to obtain the composite modified zeolite molecular sieve catalyst, which is marked as a sample D1#.
Example 8
The composite modified zeolite molecular sieve catalyst prepared in the above examples was analyzed for metal loading and particle size. Taking sample 1# as a typical example, fig. 1 (a) is a transmission electron micrograph of the sample, and fig. 1 (b) is a transmission electron micrograph of a sample of D1#, by comparison, it can be seen that the load metal is smaller in particle size, concentrated in 4.0-4.5 nm, and uniformly distributed on the surface of the carrier molecular sieve by a concentration gradient method, i.e., the load metal particles of sample 1#. Through XRF analysis test, the loading of Cu element in sample 1# was 2.56wt%, the loading of Fe element was 0.32wt%, the loading of rare earth cerium element was 0.43wt%, while the loading of Cu element in sample D1# was 1.39wt%, the loading of Fe element was 0.21wt%, and the loading of rare earth cerium element was 0.74wt%.
Example 9
The application of the composite modified zeolite molecular sieve catalyst prepared in the above example as a denitration catalyst is evaluated under the following conditions: catalyst 1g (20-40 mesh), [ NO ]]＝[NH 3 ]＝500ppm，[O 2 ]=5%, he as carrier gas, ghsv=126000h -1 . The evaluation results are shown in FIG. 2.
As is typical for sample 1# -5#, it can be seen that NO is present at 200-400℃ x The conversion rate reaches 95%,400-500 ℃, NO x The conversion rate reaches more than 90 percent. After the reaction temperature is higher than 500 ℃, the catalytic performance is slightly reduced, but NO x Conversion is still>80%. Wherein D1# is between 200 and 400 ℃, NO x The conversion rate is only about 90%, and the denitration efficiency of the catalyst is obviously reduced after the high-temperature section is 500 ℃.
In summary, it can be seen that the conventional single concentration impregnation modification method can lead to uneven distribution of copper species in catalytic active sites, insufficient number of ionic active sites or larger metal oxide particles; the zeolite molecular sieve catalyst subjected to composite modification can effectively regulate and control the metal loading and species, and achieves the purposes of regulating the number and the existence state of the catalytic active centers. The denitration catalytic performance evaluation shows that the zeolite molecular sieve catalyst after composite modification has the characteristics of high catalytic activity, wide temperature window and high thermal stability.
The foregoing description is only a few examples of the present application and is not intended to limit the present application in any way, and although the present application is disclosed in the preferred examples, it is not intended to limit the present application, and any person skilled in the art may make some changes or modifications to the disclosed technology without departing from the scope of the technical solution of the present application, and the technical solution is equivalent to the equivalent embodiments.
Claims (13)
1. The preparation method of the composite modified zeolite molecular sieve catalyst is characterized by at least comprising the following steps:
(1) Carrying out dehydration pretreatment on a carrier zeolite molecular sieve;
(2) Placing the carrier zeolite molecular sieve subjected to dehydration pretreatment in a copper salt aqueous solution I, impregnating the carrier zeolite molecular sieve with the copper salt aqueous solution I, and filtering to obtain a solid I;
the concentration of the copper salt aqueous solution I is 1-10M;
(3) Placing the solid I obtained in the step (2) into a copper salt water solution II, dipping the II, and filtering to obtain a solid II;
the concentration of the copper salt aqueous solution II is 0.1-1.0M;
(4) Placing the solid II obtained in the step (3) into a copper salt water solution III, adding ferric salt and/or rare earth metal salt, dipping the III, and filtering to obtain a solid III;
the concentration of the copper salt aqueous solution III is 0.01-0.10M;
(5) Drying and roasting the solid III obtained in the step (4) to obtain the composite modified zeolite molecular sieve catalyst;
in the composite modified zeolite molecular sieve catalyst, the load of Cu element is 0.3-10wt% and the load of multi-element metal element is 0.1-5wt%;
wherein the multi-element metal element refers to iron and/or rare earth metal element.
2. The method for producing a composite modified zeolite molecular sieve catalyst according to claim 1, wherein the carrier zeolite molecular sieve is at least one selected from CHA-type zeolite molecular sieve, MFI-type zeolite molecular sieve, BEA-type zeolite molecular sieve.
3. The method for preparing a composite modified zeolite molecular sieve catalyst according to claim 2, wherein the CHA-type zeolite molecular sieve is at least one selected from SSZ-13 zeolite molecular sieve and SAPO zeolite molecular sieve.
4. The method for preparing a composite modified zeolite molecular sieve catalyst according to claim 2, wherein the MFI-type zeolite molecular sieve is at least one selected from the group consisting of ZSM-5 zeolite molecular sieve and S-1 zeolite molecular sieve.
5. The method of preparing a composite modified zeolite molecular sieve catalyst according to claim 2, wherein the BEA-type zeolite molecular sieve is selected from Beta zeolite molecular sieves.
6. The method for preparing the composite modified zeolite molecular sieve catalyst according to claim 1, wherein the copper salt in the copper salt aqueous solution is at least one selected from copper nitrate, copper acetate and copper sulfate.
7. The method for preparing a composite modified zeolite molecular sieve catalyst according to claim 1, wherein in the step (4), the iron salt is at least one selected from the group consisting of ferric nitrate, ferric sulfate and ferric chloride.
8. The method for preparing a composite modified zeolite molecular sieve catalyst according to claim 1, wherein the amount of the ferric salt is 0.3-10% of the mass of the carrier zeolite molecular sieve;
wherein the amount of the iron salt is calculated by the mass of the Fe element contained therein.
9. The method for preparing a composite modified zeolite molecular sieve catalyst according to claim 1, wherein in step (4), the rare earth metal of the rare earth metal salt is selected from at least one of La, ce, pr, nb.
10. The method for preparing a composite modified zeolite molecular sieve catalyst according to claim 1, wherein the rare earth metal salt is used in an amount of 0.3 to 10% of the mass of the carrier zeolite molecular sieve;
wherein the amount of the rare earth metal salt is calculated based on the mass of the rare earth metal element contained therein.
11. The method for preparing a composite modified zeolite molecular sieve catalyst according to claim 1, wherein in the step (2), the conditions of impregnation I are: stirring for 2-20 h at 40-80 ℃;
in step (3), the conditions for impregnation II are: stirring for 2-20 h at 40-80 ℃;
in the step (4), the conditions of the impregnation III are as follows: stirring at 40-80 deg.c for 2-20 hr.
12. A denitration catalyst comprising at least one of the composite modified zeolite molecular sieve catalysts prepared by the method for preparing the composite modified zeolite molecular sieve catalyst according to any one of claims 1 to 11.
13. Use of the denitration catalyst as claimed in claim 12 in the denitration of automobile exhaust.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105413737A (en) * | 2015-11-06 | 2016-03-23 | 中国第一汽车股份有限公司 | Ion exchange/impregnation continuous preparation Fe-based molecular sieve SCR catalyst |
| CN108883403A (en) * | 2016-02-03 | 2018-11-23 | 巴斯夫公司 | The chabasie catalyst that copper and iron exchange altogether |
| CN109174173A (en) * | 2018-09-30 | 2019-01-11 | 中自环保科技股份有限公司 | A kind of molecular sieve SCR catalyst preparation method and its catalyst of preparation |
| CN109433252A (en) * | 2018-11-30 | 2019-03-08 | 大连理工大学 | A kind of CO2Aoxidize C2H6Dehydrogenation C2H4Catalyst and preparation method thereof |
-
2020
- 2020-07-31 CN CN202010762301.3A patent/CN114054075B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105413737A (en) * | 2015-11-06 | 2016-03-23 | 中国第一汽车股份有限公司 | Ion exchange/impregnation continuous preparation Fe-based molecular sieve SCR catalyst |
| CN108883403A (en) * | 2016-02-03 | 2018-11-23 | 巴斯夫公司 | The chabasie catalyst that copper and iron exchange altogether |
| CN109174173A (en) * | 2018-09-30 | 2019-01-11 | 中自环保科技股份有限公司 | A kind of molecular sieve SCR catalyst preparation method and its catalyst of preparation |
| CN109433252A (en) * | 2018-11-30 | 2019-03-08 | 大连理工大学 | A kind of CO2Aoxidize C2H6Dehydrogenation C2H4Catalyst and preparation method thereof |
Non-Patent Citations (7)
| Title |
|---|
| A multi-site kinetic model for NH3-SCR over Cu/SSZ-13;Louise Olsson等;《Applied Catalysis B: Environmental》;20150228;212–224 * |
| Mechanistic study of hydrothermally aged Cu/SSZ-13 catalysts for ammonia-SCR;Kirsten Leistnera等;《Catalysis Today》;20170425;55–64 * |
| Migration of Cu species in Cu/SAPO-34 during hydrothermal aging;Lei Wang等;《Journal of Catalysis》;20130718;68–77 * |
| One step synthesis of Fe-SSZ-13 zeolite by hydrothermal method;Kangning Niu等;《Journal of Solid State Chemistry》;20200323;121330-121336 * |
| Structure–activity relationships in NH3-SCR over Cu-SSZ-13 as probed by reaction kinetics and EPR studies;Feng Gao等;《Journal of Catalysis》;20130131;20–29 * |
| The Ce doping Cu/ZSM-5 as a new superior catalyst to remove NO from diesel engine exhaust;Lei Pang等;《Chemical Engineering Journal》;20140527;394–401 * |
| 用CO 连续吸附原位DRIFT 法研究Cu/SSZ-13 的Cu+存在状态;刘家旭等;《第十九届全国分子筛学术大会（武汉）》;20171024;FA-08 * |
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