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WO2022142836A1 - 一种催化组合物、催化剂层、催化装置和气体处理系统 - Google Patents

一种催化组合物、催化剂层、催化装置和气体处理系统 Download PDF

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WO2022142836A1
WO2022142836A1 PCT/CN2021/131411 CN2021131411W WO2022142836A1 WO 2022142836 A1 WO2022142836 A1 WO 2022142836A1 CN 2021131411 W CN2021131411 W CN 2021131411W WO 2022142836 A1 WO2022142836 A1 WO 2022142836A1
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molecular sieve
catalytic
transition metal
layer
catalyst layer
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PCT/CN2021/131411
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English (en)
French (fr)
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唐杨
赵峰
刘中清
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中化学科学技术研究有限公司
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Publication of WO2022142836A1 publication Critical patent/WO2022142836A1/zh

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    • 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
    • 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
    • B01J29/80—Mixtures of different zeolites
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/02—Impregnation, coating or precipitation
    • 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
    • B01J37/30—Ion-exchange
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
    • F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters

Definitions

  • the present invention relates to the field of catalysts, in particular to a catalytic composition, a catalyst layer, a catalytic device and a gas treatment system.
  • the related art employs a selective reduction catalysis (SCR) process to remove nitrogen oxides NO x .
  • SCR selective reduction catalysis
  • an aqueous urea solution is injected into the engine exhaust.
  • the aqueous urea solution undergoes hydrolysis and pyrolysis to generate NH 3 , and then under the action of the SCR catalyst, the NH 3 is enriched in oxygen. It can selectively react with NO x under conditions to generate N 2 and H 2 O.
  • the NOx reduction process can involve one or more of the following chemical reactions:
  • molecular sieves have been used as SCR catalysts.
  • Molecular sieves are microporous crystalline solids with a specific structure, that is, a crystalline or pseudo-crystalline structure formed by molecular tetrahedral unit cells forming a framework in a regular and/or repeated interconnected manner.
  • the framework usually contains silicon, aluminum and oxygen, and may also contain cations in its voids.
  • Unique molecular sieve frameworks recognized by the International Molecular Sieve Association (IZA) Structure Committee are assigned a three-letter code to designate their framework type.
  • Some molecular sieves have cell volumes of a few cubic nanometers and cell openings of several angstroms in diameter, which can be determined by the ring size of their cell openings.
  • “8-ring” refers to a closed ring consisting of 8 tetrahedral-coordinated silicon (or aluminum) atoms and 8 oxygen atoms.
  • Molecular sieves with small pore frameworks ie molecular sieves with a maximum ring size of 8, have found use in SCR applications. Small molecules such as NOx can generally enter or leave the unit cell or diffuse through the channels of small pores, whereas larger molecules such as long chain hydrocarbons cannot.
  • Small pore molecular sieves have the following catalyst layouts, such as AEI, AFT, AFX, BEA, CHA, EAB, EMT, ERI, FAU, GME, JSR, KFI, LEV, LTL, LTN, MFI, MOZ, MSO, MWW, OFF, SAS , SAT, SAV, SBS, SBT, SFW, SSF, SZR, TSC and WEN etc.
  • the SCR catalytic performance of molecular sieves can be improved by cation (Cu 2+ or Fe 3+ ) exchange.
  • cation Cu 2+ or Fe 3+
  • some ions present on the surface or framework of the molecular sieve are replaced by metal cations.
  • the catalytic composition contains a low transition metal loading molecular sieve and a high transition metal loading molecular sieve.
  • the catalytic composition cleverly utilizes the feature of high transition metal loading molecular sieves containing more free transition metals (free metals).
  • the catalytic composition has improved hydrothermal stability (resistance to hydrothermal aging) compared to single component low transition metal loading molecular sieves.
  • the catalytic composition has improved high temperature DeNOx activity compared to single component high transition metal loading molecular sieves.
  • Yet another aspect of the present disclosure provides a novel catalyst layer, which includes a first layer and a second layer, the second layer is located deeper in the catalyst layer than the first layer, the first layer contains a molecular sieve with low transition metal loading, and the second layer is located deeper in the catalyst layer than the first layer.
  • the layers contain high transition metal loading molecular sieves.
  • This scheme cleverly utilizes the temperature gradient characteristic of the catalyst layer when it is working. The first layer contacts the hot air flow before the second layer, so the temperature of the first layer is better than that of the second layer.
  • the overall catalytic activity of the catalyst layer is improved by arranging molecular sieves with low transition metal loadings with better high temperature activity in the first layer and high transition metal loading molecular sieves with better low temperature activity in the second layer.
  • Yet another aspect of the present disclosure provides a novel gas treatment system comprising a first catalytic zone and a second catalytic zone, wherein the first catalytic zone is located upstream of the second catalytic zone relative to the gas stream to be treated passing through the system, and the first catalytic zone is located upstream of the second catalytic zone.
  • One catalytic zone contains low transition metal loading molecular sieves
  • the second catalytic zone contains high transition metal loading molecular sieves.
  • the overall catalytic activity of the gas treatment system is improved by arranging molecular sieves with low transition metal loadings with better high temperature activity in the first catalytic zone, and high transition metal loading molecular sieves with better low temperature activity in the second catalytic zone.
  • the present disclosure provides a catalytic composition comprising:
  • the first molecular sieve contains a first non-aluminum transition metal element with a loading amount of m%;
  • the second molecular sieve contains the second non-aluminum transition metal element with a loading of n%;
  • the loading is based on the weight percentage of oxides of non-aluminum transition metals.
  • first non-aluminum transition metal element and the second non-aluminum transition metal element are each independently selected from one or more of the following: Cu, Fe, Mn and Ce.
  • the weight ratio of the first molecular sieve to the second molecular sieve is 1-100: 1-100.
  • A 1-100, such as 1-2, 2-3, 3-4, 4-5, 5-6, 6 ⁇ 7, 7 ⁇ 8, 8 ⁇ 9, 9 ⁇ 10, 10 ⁇ 20, 20 ⁇ 30, 30 ⁇ 40, 40 ⁇ 50, 50 ⁇ 60, 60 ⁇ 70, 70 ⁇ 80, 80 ⁇ 90, 90 ⁇ 100.
  • the first non-aluminum transition metal is present in the molecular sieve as exchanged metal and/or free metal.
  • the second non-aluminum transition metal is present in the molecular sieve as exchanged metal and/or free metal.
  • non-aluminum transition metals can be exchanged, for example, with atomic constituents at atomic exchange sites in the molecular sieve structure, which can be referred to as "exchange metals.”
  • the transition metal may be present in the molecular sieve as an unexchanged transition metal in salt form, eg, within the pores of the molecular sieve.
  • unexchanged transition metal salts decompose to form transition metal oxides, which may be referred to as "free metals.”
  • the transition metal loading exceeds the saturation limit of atomic exchange sites (ie, all exchange sites are exchanged), unexchanged transition metals may be present in the molecular sieve.
  • 1-50 wt % eg 1-5 wt %, eg 6-10 wt %, eg 11-15 wt %, eg 16-20 wt %, eg 21-25 wt %, such as 26-30 wt%, such as 31-35 wt%, such as 36-40 wt%, such as 41-45 wt%, such as 46-50 wt%) of the non-aluminum transition metal element is present in the form of free metal.
  • the method for quantitatively detecting the loading of free metals in the catalytic composition comprises the following steps: subjecting the slurry containing the catalyst composition to centrifugal treatment, the rotational speed of the centrifugal treatment is 20,000 rpm, and the time is 10 min, and the centrifuged product is collected. In the supernatant liquid, the content value of the non-aluminum transition metal in the supernatant liquid is detected, and the content of the free metal in the catalytic composition is calculated according to the value.
  • the exchange metal loading in the catalytic composition is equal to the difference between the total non-aluminum transition metal loading and the free metal loading.
  • the present disclosure provides a method of preparing the above-described catalytic composition, comprising:
  • a precursor of a first non-aluminum transition metal element eg, a salt of a first non-aluminum transition metal element
  • a first solvent eg, water
  • a precursor of a second non-aluminum transition metal element eg, a salt of a second non-aluminum transition metal element
  • a second solvent eg, water
  • the present disclosure provides a catalyst layer comprising:
  • the first layer contains a first molecular sieve, and the first molecular sieve contains a first non-aluminum transition metal element with a loading amount of m%;
  • the second layer, the second layer contains a second molecular sieve, and the second molecular sieve contains a second non-aluminum transition metal element with a loading of n%;
  • the loading is based on the weight percentage of the oxides of non-aluminum transition metals in the molecular sieve
  • the position of the second layer in the catalyst layer is deeper than that of the first layer
  • first non-aluminum transition metal element and the second non-aluminum transition metal element are each independently selected from one or more of the following: Cu, Fe, Mn and Ce;
  • the weight of the first molecular sieve > the weight of the second molecular sieve ⁇ 0;
  • the weight of the second molecular sieve >the weight of the first molecular sieve ⁇ 0.
  • the first layer and the second layer do not overlap.
  • the depth of the first layer (or second layer) at the catalyst layer is calculated as the distance from the lower surface of the first layer (or second layer) to the upper surface of the catalyst layer.
  • the weight ratio of molecular sieves contained in the first layer to molecular sieves contained in the second layer is 1-5:1-5, such as 1-2:1-2, such as 2:1.
  • the thickness ratio of the first layer to the second layer is from 1 to 5:1 to 5, eg, 2:1.
  • the present disclosure provides a catalytic device comprising a substrate and the catalyst layer described above, the catalyst layer covering at least a portion of the surface of the substrate.
  • the substrate has a porous structure.
  • the substrate has a cellular porous structure.
  • the present disclosure provides a method of preparing the above-described catalyst layer, comprising:
  • the precursor of the first non-aluminum transition metal element for example, the salt of the first non-aluminum transition metal element
  • the first solvent for example, water
  • the present disclosure provides a gas processing system comprising:
  • the first catalytic zone contains a first molecular sieve, and the first molecular sieve contains a first non-aluminum transition metal element with a loading amount of m%;
  • the second catalytic zone, the second catalytic zone contains a second molecular sieve, and the second molecular sieve contains a second non-aluminum transition metal element with a loading amount of n%;
  • first catalytic zone is located upstream of the second catalytic zone relative to the gas stream to be treated passing through the system
  • the loading is based on the weight percentage of the oxides of non-aluminum transition metals in the molecular sieve
  • first non-aluminum transition metal element and the second non-aluminum transition metal element are each independently selected from one or more of the following: Cu, Fe, Mn and Ce.
  • the ratio of the weight of molecular sieve contained in the first catalytic zone to the weight of molecular sieve contained in the second catalytic zone is 1-5:1-5, such as 1-2:1-2, such as 2:1.
  • the ratio of the length of the first catalytic zone in this direction to the length of the second catalytic zone in this direction in the direction of the gas stream to be treated passing through the above system is 1-5:1-5, For example 2:1.
  • the present disclosure provides methods of making the above-described gas processing systems, comprising
  • the precursor of the first non-aluminum transition metal element for example, the salt of the first non-aluminum transition metal element
  • the first solvent for example, water
  • the temperature of the calcination process is 400-500°C.
  • a drying process is also performed before the calcination process.
  • both the first non-aluminum transition metal element and the second non-aluminum transition metal element are copper (Cu) elements.
  • m n.
  • m n
  • n-m ⁇ 0.2 such as n-m ⁇ 0.4, n-m ⁇ 0.6, such as n-m ⁇ 0.8, such as n-m ⁇ 1, such as n-m ⁇ 1.2, such as n-m ⁇ 1.4, such as n-m ⁇ 1.6, such as n-m ⁇ 1.8, such as n-m ⁇ 2.0, such as n-m ⁇ 2.2, such as n-m ⁇ 2.4.
  • n-m 0.2-5.
  • the first molecular sieve and the second molecular sieve are SCR-active molecular sieves.
  • the first molecular sieve and the second molecular sieve are small pore molecular sieves, preferably, the small pore molecular sieves have an average pore size of 0.1-1 nm, such as 0.2-0.8 nm, such as 0.3-0.6 nm, such as 0.3-0.4 nm .
  • the first molecular sieve and the second molecular sieve have the same framework structure.
  • the first molecular sieve and the second molecular sieve have different framework structures.
  • the first molecular sieve and the second molecular sieve each independently have one or more of the following framework structures: AEI, AFT, AFX, BEA, CHA, EAB, EMT, ERI, FAU, GME, JSR, KFI, LEV, LTL, LTN, MFI, MOZ, MSO, MWW, OFF, SAS, SAT, SAV, SBS, SBT, SFW, SSF, SZR, TSC and WEN.
  • framework structures AEI, AFT, AFX, BEA, CHA, EAB, EMT, ERI, FAU, GME, JSR, KFI, LEV, LTL, LTN, MFI, MOZ, MSO, MWW, OFF, SAS, SAT, SAV, SBS, SBT, SFW, SSF, SZR, TSC and WEN.
  • the first molecular sieve and the second molecular sieve each independently have one or more of the following framework structures: AEI, AFT, AFX, CHA, EAB, ERI, KFI, LEV, SAS, SAT, and SAV.
  • the first molecular sieve and the second molecular sieve each independently have one or more of the following framework structures: AEI, CHA.
  • the first molecular sieve and the second molecular sieve have an AEI framework structure.
  • the first molecular sieve has an AEI framework structure and the second molecular sieve has a CHA framework structure.
  • the first molecular sieve is a SSZ-39 molecular sieve and the second molecular sieve is a SSZ-13 molecular sieve.
  • the first molecular sieve and the second molecular sieve each independently have a silica to alumina ratio of 10-50.
  • the catalytic composition, the first catalyst layer, the second catalyst layer, the first catalytic zone, or the second catalytic zone contains zirconia.
  • the weight content of zirconia in the catalytic composition, the first catalyst layer, the second catalyst layer, the first catalytic zone or the second catalytic zone is 1-20 wt %, such as 1-10 wt %, such as 2 -10wt%.
  • a gas permeable cooling layer is provided between the first layer and the second layer.
  • the cooling layer does not contain a selective reduction catalyst.
  • a cooling zone is provided between the first catalytic zone and the second catalytic zone.
  • the cooling layer or the cooling zone has a porous structure, and the temperature of the gas is further lowered after passing/flowing through the cooling layer or the cooling zone.
  • the present disclosure provides the use of a catalytic composition, catalyst layer, catalytic device or gas treatment system for catalytic selective catalytic reduction (SCR), eg, for catalytic selective catalytic reduction (SCR) removal of nitrogen oxides use of things.
  • SCR selective catalytic reduction
  • SCR catalytic selective catalytic reduction
  • the first molecular sieve and the second molecular sieve are each independently a zeolite molecular sieve.
  • the molecular sieve has a silica/alumina molar ratio (SAR ).
  • the catalyst layer is the sintered product of a coating of catalytic slurry.
  • the catalytic slurry contains the following components: a molecular sieve, a precursor of a non-aluminum transition metal (eg, a salt of a non-aluminum transition metal, such as a non-aluminum transition metal acetate or nitrate), and a solvent (eg, water) .
  • a molecular sieve e.g, a molecular sieve
  • a precursor of a non-aluminum transition metal eg, a salt of a non-aluminum transition metal, such as a non-aluminum transition metal acetate or nitrate
  • a solvent eg, water
  • the catalytic slurry also contains a binder (eg, zirconium acetate).
  • a binder eg, zirconium acetate
  • the catalytic slurry also contains acetic acid.
  • the catalytic slurry also contains a surfactant.
  • the catalytic slurry has a solids content of 30-50 wt%.
  • the loading of the catalyst layer on the catalytic device is 1-5 g/inch 3 , such as 2-3 g/inch 3 , such as 2.3 g/inch 3 .
  • the catalytic composition for use in the present invention may be coated on a suitable substrate or may be shaped as an extruded catalyst.
  • the catalyst is coated on a flow-through substrate (ie, a honeycomb monolithic catalyst support having many small parallel channels axially passing through the entire part) or a wall-flow filter, such as a wall-flow filter.
  • the catalysts used in the present invention may be coated, for example, as a washcoat component on a suitable monolithic substrate, such as a metallic or ceramic flow-through monolithic substrate, or a filter substrate, such as a wall-flow filter or sintered metal or partial filter on the device.
  • the catalysts used in the present invention can be synthesized directly onto the substrate.
  • the catalytic compositions of the present invention can be formed into extruded flow-through catalysts. Such extruded catalysts can be formed into catalyst cartridges. Other forms such as pellets, beads or other shaped catalysts are possible.
  • Active coating compositions containing the molecular sieve-supported transition metal catalysts of the present invention for coating onto substrates may contain other ingredients known to those of ordinary skill in the art.
  • a reactive coating composition may additionally comprise a compound selected from the group consisting of alumina, silica, (non - molecular sieve) silica - alumina, naturally occurring clays, TiO2 , ZrO2, CeO2 and SnO2 , and their Adhesives for mixtures and combinations.
  • the catalytic composition can be first prepared as a slurry and applied to a substrate as a reactive coating slurry composition using any known method.
  • the first catalytic zone is provided with a catalyst layer, the catalyst layer contains a first molecular sieve, and the first molecular sieve contains a first non-aluminum transition metal element with a loading of m%.
  • the second catalytic zone is provided with a catalyst layer, the catalyst layer contains a second molecular sieve, and the second molecular sieve contains a second non-aluminum transition metal element with a loading of n%.
  • the first layer contains molecular sieve, and the weight content of molecular sieve is more than 1%, such as more than 10%, such as more than 20%, such as more than 30%, such as more than 40%, based on the total weight of the first layer , such as more than 50%, such as more than 60%, such as more than 70%, such as more than 80%, such as more than 90%, such as 100%.
  • the above molecular sieve refers to the first molecular sieve, the second molecular sieve or the sum of the first molecular sieve and the second molecular sieve.
  • the second layer contains molecular sieve, and based on the total weight of the second layer, the weight content of molecular sieve is 1% or more, such as 10% or more, such as 20% or more, such as 30% or more, such as 40% or more , such as more than 50%, such as more than 60%, such as more than 70%, such as more than 80%, such as more than 90%, such as 100%.
  • the above molecular sieve refers to the first molecular sieve, the second molecular sieve or the sum of the first molecular sieve and the second molecular sieve.
  • the first catalytic zone contains molecular sieve
  • the weight content of molecular sieve is 1% or more, such as 10% or more, such as 20% or more, such as 30% or more, based on the total coating weight of the first catalytic zone, For example, 40% or more, such as 50% or more, such as 60% or more, such as 70% or more, such as 80% or more, such as 90% or more, such as 100%.
  • the above molecular sieve refers to the first molecular sieve, the second molecular sieve or the sum of the first molecular sieve and the second molecular sieve.
  • the second catalytic zone contains molecular sieve, based on the total coating weight of the first layer, the molecular sieve is present in an amount of 1% or more, such as 10% or more, such as 20% or more, such as 30% or more, such as 40% or more, such as 50% or more, such as 60% or more, such as 70% or more, such as 80% or more, such as 90% or more, such as 100%.
  • the above molecular sieve refers to the first molecular sieve, the second molecular sieve or the sum of the first molecular sieve and the second molecular sieve.
  • the first molecular sieve is 0.5-5 g/inch 3 (eg, 0.5-1 g/inch 3 , 1-2 g/inch 3 , 2-3 g/inch 3 , 3-4 g/inch 3 , 4-5 g/inch 3 ) inch 3 , eg, 1.4 g/inch 3 ) loading (based on molecular sieve weight) was deposited on a 1 inch diameter and 3 inch length with a pore density of 400 cpsi (pores per square inch) and a wall thickness of 6 mils.
  • the catalyst is effective to provide 80-100% (eg 90-100%, eg 95-100%) average NO conversion over the following temperature ranges (350-400°C, 400-450°C, 450-500°C or 350-500°C) Rate.
  • the second molecular sieve is 0.5-5 g/inch 3 (eg, 0.5-1 g/inch 3 , 1-2 g/inch 3 , 2-3 g/inch 3 , 3-4 g/inch 3 , 4-5 g/inch 3 ) inch 3 , eg, 0.7 g/inch 3 ) loading (based on molecular sieve weight) was deposited on a 1 inch diameter and 3 inch length with a pore density of 400 cpsi (pores per square inch) and a wall thickness of 6 mils.
  • the catalyst is effective to provide 80-100% (eg 90-100%, eg 95-100%) average NO conversion in the following temperature range (200-250°C or 250-300°C).
  • the catalytic composition, catalyst layer, catalytic device or gas treatment system is characterized in that the molecular sieve is 0.5-5 g/inch 3 (eg, 0.5-1 g/inch 3 , 1-2 g/inch 3 , 2-3 g /inch 3 , 3-4 g/inch 3 , 4-5 g/inch 3 , such as 0.7 g/inch 3 ) loadings (by weight of molecular sieve) deposited on a cell having a pore density of 400 cpsi (pores per square inch) and 6 densities 1 inch diameter and 3 inch length honeycomb porous ceramic support with 1 inch wall thickness in a feed stream containing 500 ppm NO, 500 ppm NH 3 , 10% O 2 , 5% H 2 at a space velocity of 80,000 hr -1 O.
  • N °C, 450-500°C, or 200-500°C provides an average NO conversion of 80-100% (eg, 90-100%, eg
  • the catalytic composition, catalyst layer, catalytic device, or gas treatment system is characterized in that the catalyst (by weight of molecular sieve) is 0.5-5 g/inch 3 (eg, 0.5-1 g/inch 3 , 1-2 g/inch 3 ) inch 3 , 2-3 g/inch 3 , 3-4 g/inch 3 , 4-5 g/inch 3 , e.g.
  • molecular sieves refer to first molecular sieves or second molecular sieves if not otherwise specified.
  • molecular sieve refers to the sum of the first molecular sieve and the second molecular sieve unless otherwise specified.
  • the non-aluminum transition metal element refers to the first non-aluminum transition metal element or the second non-aluminum transition metal element.
  • the non-aluminum transition metal element refers to the sum of the first non-aluminum transition metal element and the second non-aluminum transition metal element.
  • the catalytic composition/catalyst layer/catalytic device/gas treatment system can treat processes from combustion, such as from internal combustion engines (whether mobile or stationary), gas turbines and coal, oil or natural gas fired plants or engines carried out on the gas.
  • the method can also be used to treat gases from industrial processes such as refining, from refinery furnaces and boilers, furnaces, chemical process industries, coke ovens, municipal waste treatment plants and incinerators, coffee roasting plants, and the like.
  • the catalytic composition/catalyst layer/catalytic device/gas treatment system of the present invention is used to treat fuel from a vehicle internal combustion engine, such as a gasoline engine, under rich fuel conditions, or from a liquid petroleum gas or natural gas powered engine Exhaust gases from stationary engines.
  • a vehicle internal combustion engine such as a gasoline engine
  • a liquid petroleum gas or natural gas powered engine Exhaust gases from stationary engines.
  • Molecular sieves are microporous crystalline solids with a specific structure, that is, a crystalline or pseudo-crystalline structure formed by molecular tetrahedral unit cells forming a framework in a regular and/or repeated interconnected manner.
  • the framework usually contains silicon, aluminum and oxygen, and may also contain cations in its voids.
  • Unique molecular sieve frameworks recognized by the International Molecular Sieve Association (IZA) Structure Committee are assigned a three-letter code to designate their framework type.
  • small pore molecular sieve refers to a molecular sieve having a maximum ring size of 8.
  • catalyst refers to a material that promotes a reaction.
  • catalytic composition refers to a combination of two or more catalysts, eg, a combination of two different materials that promote a reaction.
  • the catalytic composition may be in the form of a washcoat.
  • nitrogen oxides NOx denotes nitrogen oxides, especially nitrous oxide (N 2 O), nitrous oxide (NO), nitrous oxide (N 2 O 3 ), nitrogen dioxide (NO 2 ), tetroxide Dinitrogen (N 2 O 4 ), dinitrogen pentoxide (N 2 O 5 ), nitrogen peroxide (NO 3 ).
  • Consisting of may mean that the content is greater than zero, such as 1% or more, such as 10% or more, such as 20% or more, such as 30% or more, such as 40% or more, such as 50% or more, such as 60% or more , such as more than 70%, such as more than 80%, such as more than 90%, such as 100%.
  • the meanings of "comprising”, “including” and “containing” are equivalent to “consisting of”.
  • % generally refers to % by weight.
  • the catalytic composition/catalyst layer/catalyst device/gas treatment system has improved DeNOx activity.
  • the catalytic composition/catalyst layer/catalyst device/gas treatment system has improved resistance to hydrothermal aging.
  • Figure 1 shows a schematic diagram of the catalyst layout of a catalytic device
  • Figure 2 shows a schematic diagram of the catalyst layout of a catalytic device.
  • the copper loading of molecular sieve is calculated by the following formula:
  • the catalytic device has the following catalyst layout: 3.6 wt% CuO/AEI in the upstream zone and 4.8 wt% CuO/AEI in the downstream zone.
  • FIG. 1 shows a schematic diagram of the catalyst layout of the catalytic device of Example 1.
  • the catalytic device includes a first catalytic zone 11 , the first catalytic zone 11 contains a first molecular sieve, and the first molecular sieve contains a loading of 3.6 wt % copper element; the second catalytic zone 12, the second catalytic zone contains a second molecular sieve, the second molecular sieve contains a copper element with a loading of 4.8 wt%; wherein relative to the gas stream 6 to be treated passing through the system, the first catalytic zone 11 is located upstream of the second catalytic zone 12 .
  • the preparation method of the catalytic device of embodiment 1 is as follows:
  • Preparation of the first slurry 120 g of copper acetate and 1000 g of molecular sieve (AEI structure) were added to 1000 g of deionized water and stirred for 30 minutes. With stirring, 10 g of dilute acetic acid and 150 g of zirconium acetate binder (containing 30% ZrO 2 ) were added In the slurry, a certain amount of surfactant is added to adjust the properties of the slurry, and the slurry is ground, and finally the slurry is prepared to a solid content of 40%.
  • AEI structure molecular sieve
  • Preparation of the second slurry 160 g of copper acetate and 1000 g of molecular sieve (AEI structure, Si-Al ratio 16) were added to 1000 g of deionized water and stirred for 30 minutes. With stirring, 10 g of dilute acetic acid and 150 g of zirconium acetate binder (containing 30 % ZrO 2 ) was added to the slurry, and then a certain amount of surfactant was added to adjust the properties of the slurry, and the slurry was ground, and finally the slurry was prepared to a solid content of 40%.
  • AEI structure, Si-Al ratio 16 molecular sieve
  • a cellular porous ceramic support having a pore density of 400 cpsi (pores per square inch) and a wall thickness of 6 mils, a diameter of 1 inch and a length of 3 inches was provided.
  • the carrier is divided into an upstream region and a downstream region along its length direction, and the length ratio of the upstream region to the downstream region is 2:1.
  • the first slurry is applied to the region upstream of the carrier and the second slurry is applied to the region downstream of the carrier.
  • the coated carrier was dried at 120° C. for 1 h, and calcined at 450° C. for 30 minutes to form a catalyst layer on the carrier to obtain the catalytic device of this embodiment.
  • the upstream area of the catalytic device has a copper-containing molecular sieve (3.6wt%CuO/AEI) with a copper loading of 3.6wt%, and the downstream area is provided with a copper-containing molecular sieve with a copper loading of 4.8wt% (4.8wt%CuO/AEI). AEI).
  • the average copper loading of the molecular sieve on the catalytic device was 4 wt%.
  • the coating loading of the catalytic device was 2.3 g/inch 3 .
  • the catalytic device had the following catalyst layout: 3.6 wt% CuO/AEI in the upstream zone and 4.8 wt% CuO/CHA in the downstream zone.
  • Example 2 is similar to Example 1, the difference is: when preparing the second slurry in Example 2, 1000 g of CHA molecular sieve was used to replace the 1000 g of AEI molecular sieve used in Example 1. After the second slurry of Example 2 is calcined, a copper-containing molecular sieve (4.8 wt% CuO/CHA) with a copper loading of 4.8 wt % can be obtained. Other steps and parameters are the same as in Example 1.
  • the upstream area of the catalytic device is covered with a copper-containing molecular sieve (3.6 wt% CuO/AEI) with a copper loading of 3.6 wt%
  • the downstream area is covered with a copper-containing molecular sieve with a copper loading of 4.8 wt% (4.8 wt% CuO /CHA).
  • the average copper loading of the molecular sieve on the catalytic device was 4 wt%.
  • the coating loading of the catalytic device was 2.3 g/inch 3 .
  • the catalytic device has the following catalyst layout: the upper layer of the catalyst layer is 3.6 wt% CuO/AEI, and the lower layer of the catalyst layer is 4.8 wt% CuO/AEI.
  • FIG. 2 shows a schematic diagram of the catalyst layout of a catalytic device.
  • the catalytic device includes a catalyst layer 2.
  • the catalyst layer 2 includes a first layer 21 and a second layer 22.
  • the first layer 21 contains a first molecular sieve, A molecular sieve contains copper with a copper loading of 3.6 wt %;
  • the second layer 22 contains a second molecular sieve, and the second molecular sieve contains copper with a copper loading of 4.8 wt %.
  • the position of the second layer 22 in the catalyst layer 2 is deeper than that of the first layer 21 , that is, the distance from the second layer 22 to the gas stream 6 to be treated is farther than that of the first layer 21 .
  • Example 1 The same first and second slurries as in Example 1 were prepared.
  • a cellular porous ceramic support having a pore density of 400 cpsi (pores per square inch) and a wall thickness of 6 mils, a diameter of 1 inch and a length of 3 inches was provided.
  • the second slurry was coated on the above-mentioned carrier, and dried at 120° C. for 1 h after coating to serve as the second layer.
  • the first layer was then coated on the undercoat layer, and dried at 120° C. for 1 h after coating to serve as the first layer.
  • the coated carrier was calcined at 450° C. for 30 minutes to form a catalyst layer on the carrier to obtain the catalyst device of Example 3.
  • the catalyst device has a catalyst layer with a double-layer structure.
  • the first layer (upper layer) of the catalyst layer has a copper-containing molecular sieve with a copper loading of 3.6 wt% (3.6 wt% CuO/AEI), and the second layer (lower layer) of the catalyst layer has a copper-containing molecular sieve with a copper loading of 4.8 wt%. (4.8 wt% CuO/AEI), and the dry weight ratio of the first and second layers was 2:1.
  • the average copper loading of the molecular sieve on the catalytic device was 4 wt%.
  • the coating loading of the catalytic device was 2.3 g/inch 3 .
  • the catalytic device has the following catalyst layout: the upper layer of the catalyst layer is 3.6 wt% CuO/AEI, and the lower layer of the catalyst layer is 4.8 wt% CuO/CHA.
  • Example 2 The same first and second slurries as in Example 2 were prepared.
  • a cellular porous ceramic support having a pore density of 400 cpsi (pores per square inch) and a wall thickness of 6 mils, a diameter of 1 inch and a length of 3 inches was provided.
  • the second slurry was coated on the above-mentioned carrier, and dried at 120° C. for 1 h after coating to serve as the second layer.
  • the first layer was then coated on the undercoat layer, and dried at 120° C. for 1 h after coating to serve as the first layer.
  • the coated carrier was calcined at 450° C. for 30 minutes to form a catalyst layer on the carrier to obtain the catalyst device of Example 4.
  • the catalyst device has a catalyst layer with a double-layer structure.
  • the first layer (upper layer) of the catalyst layer has a copper-containing molecular sieve with a copper loading of 3.6 wt% (3.6 wt% CuO/AEI), and the second layer (lower layer) of the catalyst layer has a copper-containing molecular sieve with a copper loading of 4.8 wt%. (4.8 wt% CuO/CHA), and the dry weight ratio of the first and second layers was 2:1.
  • the average copper loading of the molecular sieve on the catalytic device was 4 wt%.
  • the coating loading of the catalytic device was 2.3 g/inch 3 .
  • Preparation of the first suspension 120g of copper acetate and 1000g of molecular sieves (AEI structure, silicon-alumina ratio of 16) were added to deionized water and stirred for 30 minutes, followed by adding 10g of dilute acetic acid and 150g of zirconium acetate binder ( containing 30% ZrO 2 ) to obtain a first suspension.
  • AEI structure silicon-alumina ratio of 16
  • Preparation of the second suspension add 160g copper acetate and 1000g molecular sieve (AEI structure, the ratio of silicon to aluminum is 16) into 1000g deionized water and stir for 30 minutes, add 10g dilute acetic acid and 150g zirconium acetate binder (containing 30% ZrO 2 ) to obtain a second suspension.
  • AEI structure the ratio of silicon to aluminum is 16
  • Preparation of mixed slurry Mix the first suspension and the second suspension according to the dry weight ratio of 2:1, then add a certain amount of surfactant to adjust the properties of the slurry, and grind, and finally prepare the slurry to 40% solids content.
  • a cellular porous ceramic support having a pore density of 400 cpsi (pores per square inch) and a wall thickness of 6 mils, a diameter of 1 inch and a length of 3 inches was provided.
  • the mixed slurry was coated on the above carrier, the coated carrier was dried at 120°C for 1 h, and calcined at 450°C for 30 minutes to form a catalyst layer on the carrier to obtain the catalyst device of Example 5.
  • the catalyst layer contains a mixed first copper-containing molecular sieve and a second copper-containing molecular sieve, and the mass ratio of the two is 2:1.
  • the first copper-containing molecular sieve is a copper-containing molecular sieve with a copper loading of 3.6wt% (3.6wt%CuO/AEI)
  • the second copper-containing molecular sieve is a copper-containing molecular sieve with a copper loading of 4.8wt% (4.8wt%CuO/AEI).
  • the average copper loading of the molecular sieve on the catalytic device was 4 wt%.
  • the coating loading of the catalytic device was 2.3 g/inch 3 .
  • Example 6 is similar to Example 5, with the difference that: when preparing the second suspension in Example 6, 1000g of CHA molecular sieves were used to replace the 1000g of AEI molecular sieves used in Example 5. Other steps and parameters are the same as in Example 5.
  • the catalyst layer contains a mixed first copper-containing molecular sieve and a second copper-containing molecular sieve, and the mass ratio of the two is 2:1.
  • the first copper-containing molecular sieve is a copper-containing molecular sieve with a copper loading of 3.6wt% (3.6wt%CuO/AEI)
  • the second copper-containing molecular sieve is a copper-containing molecular sieve with a copper loading of 4.8wt% (4.8wt%CuO/CHA).
  • the average copper loading of the molecular sieve on the catalytic device was 4 wt%.
  • the coating loading of the catalytic device was 2.3 g/inch 3 .
  • a cellular porous ceramic support having a pore density of 400 cpsi (pores per square inch) and a wall thickness of 6 mils, a diameter of 1 inch and a length of 3 inches was provided.
  • the mixed slurry was coated on the carrier, the coated carrier was dried at 120° C. for 1 h, and calcined at 450° C. for 30 minutes to form a catalyst layer on the carrier to obtain the catalytic device of Comparative Example 1.
  • the catalyst layer contains a single-component molecular sieve, that is, a copper-containing molecular sieve with a copper loading of 4 wt % (4 wt % CuO/AEI).
  • the coating loading of the catalytic device was 2.3 g/inch 3 .
  • Example 2 is similar to Comparative Example 1, the difference is: when preparing the slurry of the copper-loaded molecular sieve in Comparative Example 2, 1000 g of CHA molecular sieve was used to replace the 1000 g of AEI molecular sieve used in Comparative Example 1. Other steps and parameters are the same as in Comparative Example 1.
  • the catalyst layer contains a single-component molecular sieve, that is, a copper-containing molecular sieve with a copper loading of 4 wt % (4 wt % CuO/CHA).
  • the coating loading of the catalytic device was 2.3 g/inch 3 .
  • a reactor comprising the catalytic device of the comparative example of the above-described embodiment is provided.
  • the gas to be catalyzed was introduced into the reactor, and its composition was as follows: 500 ppm NO, 500 ppm NH 3 , 10% O 2 , 5% H 2 O, and N 2 was used as the balance gas.
  • the catalytic reaction was carried out at a space velocity of 80,000 h ⁇ 1 in the temperature range of 150°C-600°C.
  • the composition of the gas before and after the catalytic reaction was analyzed, and the NOx conversion rate was calculated according to the following formula:
  • (1) represents the mass of each component in the gas before the catalytic reaction
  • (2) represents the mass of each corresponding component in the gas after the catalytic reaction.
  • Hydrothermal aging of fresh catalytic units The hydrothermal aging treatment conditions are as follows: in an atmosphere of 10% H 2 O content, at a temperature of 700° C., for 50 hours.
  • the data in Table 1 shows that the front and rear distribution of the molecular sieve layout (ie, the front low copper loading, the rear high copper loading) can significantly improve the NOx conversion rate at low temperature and high temperature compared with a single coating, while the upper and lower distribution of the molecular sieve layout (ie The low copper loading in the upper layer, and the high copper loading in the lower layer) slightly improved the NOx conversion at high temperature, while the uniform mixed coating of the two slurries showed little improvement over the single coating.
  • the front and rear layout ie, low copper loading in the front, high copper loading in the rear
  • the free copper content in the mixed slurries of Examples 5 and 6 and Comparative Examples 1 and 2 was detected by the following method: the mixed slurries were centrifuged at 20,000 rpm and 10 minutes for centrifugation time. The supernatant of the centrifuged product was collected, and the copper content in the supernatant was tested by ICP-MS. The results are shown in Table 2.
  • the free copper level of the uniformly mixed slurry is basically the average effect of the single slurry level in the comparative example, and there is no significant difference due to the difference between the uniform mixing of high copper loading and low copper loading. , which may also be one of the reasons why the uniform mixing of high and low copper loadings does not differ much in NOx conversion from a single slurry.
  • the proportion of free copper in the slurry of the AEI molecular sieve is relatively small, which is also the front and rear layout of the AEI molecular sieve (ie low copper loading at the front, high copper loading at the back) in the example.

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Abstract

一种催化组合物、催化剂层、催化装置和气体处理系统。该催化组合物、催化剂层和气体处理系统具有改善的SCR活性。

Description

一种催化组合物、催化剂层、催化装置和气体处理系统 技术领域
本发明涉及催化剂领域，具体涉及一种催化组合物、催化剂层、催化装置和气体处理系统。
背景技术
相关技术采用选择还原催化(SCR)过程脱除氮氧化物NO x。在一个示例性的SCR过程中，将尿素水溶液喷入发动机尾气中，在180℃以上的温度，尿素水溶液通过水解和热解反应生成NH 3，随后在SCR催化剂的作用下，NH 3在富氧条件下选择性地和NO x发生反应，生成N 2和H 2O。NO x还原过程可以涉及以下一个或多个化学反应：
1)4NH 3+4NO+O 2＝4N 2+6H 2O(标准SCR反应)
2)4NH 3+2NO+2NO 2＝4N 2+6H 2O(快速SCR反应)
3)4NH 3+3NO 2＝3.5N 2+6H 2O(慢速SCR反应)
相关技术中，分子筛已被用作SCR催化剂。分子筛是具有特定结构的微孔结晶固体，即通过分子四面体晶胞以规则和/或重复的相互连接方式构成骨架所形成的结晶或者伪结晶结构。在骨架中通常含有硅、铝和氧，并还可以在其空隙中含有阳离子。国际分子筛协会(IZA)结构委员会承认的独特分子筛骨架被分配三个字母的代码以指定其骨架类型。
一些分子筛具有几立方纳米的晶胞体积和直径几埃的晶胞开口，该晶胞可由它们的晶胞开口的环尺寸决定。例如“8-环”指的是由8个四面体配位的硅(或铝)原子与8个氧原子构成的封闭环。具有小孔骨架的分子筛，即最大环尺寸为8的分子筛，已经发现可用于SCR应用。小分子如NOx通常可以进入或离开该晶胞或通过小孔隙的通道扩散，而较大的分子如长链烃类不能。小孔分子筛有如下催化剂布局，如AEI、AFT、AFX、BEA、CHA、EAB、EMT、ERI、FAU、GME、JSR、KFI、LEV、LTL、LTN、MFI、MOZ、MSO、MWW、OFF、SAS、SAT、SAV、SBS、SBT、SFW、SSF、SZR、TSC和WEN等。
相关技术中，分子筛的SCR催化性能可以通过阳离子(Cu 2+或Fe 3+)交换来改善。阳离子交换过程中，存在于分子筛表面或骨架中的一部分离子被金属阳离子取代。
相关文献记载了对于Cu交换的AEI(SSZ-39)和CHA(SSZ-13)的DeNOx活性的研究。对于Cu交换的CHA结构分子筛(SSZ-13)，其在低温时(<约250℃)表现 出较高的氮氧化物转化率(即较高的DeNOx活性)；对于Cu交换的AEI结构分子筛(SSZ-39)，其在高温(>约350℃)表现出较高的DeNOx活性。此外，Cu交换的AEI结构分子筛(SSZ-39)表现出较高的水热稳定性(Shan,Yulong,et al.A Comparative Study of the Activity and Hydrothermal Stability of Al-rich Cu-SSZ-39 and Cu-SSZ-13.Applied Catalysis B:Environmental 264(2019):118511.)。
发明内容
本公开一方面提供一种新型的催化组合物。该催化组合物含有低过渡金属负载量分子筛和高过渡金属负载量分子筛。该催化组合物巧妙利用了高过渡金属负载量分子筛含有较多游离过渡金属(游离金属)的特点。由于游离金属能够抑制分子筛的DeNOx活性随水热降级，当低过渡金属负载量分子筛和高过渡金属负载量分子筛混合后，高过渡金属负载量分子筛中的游离金属能够分散至催化组合物整体，使得低过渡金属负载量分子筛也有机会利用游离金属，进而高过渡金属负载量分子筛与低过渡金属负载量分子筛形成了协同增效的效果，使得催化组合物的催化活性和抗老化稳定性获得出人意料地改善。该催化组合物与单一成分的低过渡金属负载量分子筛相比，其具有改善的水热稳定性(抗水热老化)。该催化组合物与单一成分的高过渡金属负载量分子筛相比，其具有改善的高温DeNOx活性。
本公开再一方面提供一种新型催化剂层，其包括第一层和第二层，第二层在催化剂层中的位置比第一层更深，第一层含有低过渡金属负载量分子筛，第二层含有高过渡金属负载量分子筛。该方案巧妙利用催化剂层工作时存在温度梯度的特点，第一层比第二层先接触热气流，所以第一层温度比第二层更好。通过在第一层设置高温活性更好的低过渡金属负载量分子筛，在第二层设置低温活性更好的高过渡金属负载量分子筛，实现了催化剂层总体催化活性的提高。
本公开再一方面提供一种新型气体处理系统，其包括第一催化区和第二催化区，其中相对于穿过该系统的待处理气流，第一催化区位于第二催化区的上游，第一催化区含有低过渡金属负载量分子筛，第二催化区含有高过渡金属负载量分子筛。该方案巧妙利用催化区工作时存在温度梯度的特点，第一催化区比第二催化区先接触热气流，所以第一催化区比第二催化区温度更好。通过在第一催化区设置高温活性更好的低过渡金属负载量分子筛，在第二催化区设置低温活性更好的高过渡金属负载量分子筛，实现了气体处理系统总体催化活性的提高。
基于上述发明构思，进一步详述本公开方案如下：
在一些方面，本公开提供一种催化组合物，包括：
第一分子筛，第一分子筛含有负载量为m％的第一非铝过渡金属元素；
第二分子筛，第二分子筛含有负载量为n％的第二非铝过渡金属元素；
其中，0＜m≤n＜100；
其中，负载量以非铝过渡金属的氧化物的重量百分含量计。
其中，第一非铝过渡金属元素和第二非铝过渡金属元素各自独立地选自以下的一种或多种：Cu、Fe、Mn和Ce。
在一些实施方案中，第一分子筛与第二分子筛的重量比为1～100:1～100。
在一些实施方案中，第一分子筛与第二分子筛的重量比为A:B，其中，A＝1～100，例如1～2、2～3、3～4、4～5、5～6、6～7、7～8、8～9、9～10、10～20、20～30、30～40、40～50、50～60、60～70、70～80、80～90、90～100；B＝1～100，例如1～2、2～3、3～4、4～5、5～6、6～7、7～8、8～9、9～10、10～20、20～30、30～40、40～50、50～60、60～70、70～80、80～90、90～100。
在一些实施方案中，第一非铝过渡金属以交换金属和/或游离金属的形式存在于分子筛中。
在一些实施方案中，第二非铝过渡金属以交换金属和/或游离金属的形式存在于分子筛中。
在一些实施方案中，非铝过渡金属可以例如与分子筛结构中的原子交换位点处的原子成分交换，其可以被称作“交换金属”。另外或者，该过渡金属可以作为盐形式的未交换的过渡金属存在于分子筛中，例如存在于分子筛的孔隙内。在煅烧时，未交换的过渡金属盐分解形成过渡金属氧化物，其可以被称作“游离金属”。当过渡金属载量超过原子交换位点的饱和限(即所有交换位点已交换)时，在分子筛中可能存在未交换的过渡金属。
在一些实施方案中，对于分子筛上负载的非铝过渡金属元素，1～50wt％(例如1～5wt％，例如6～10wt％，例如11～15wt％，例如16～20wt％，例如21～25wt％，例如26～30wt％，例如31～35wt％，例如36～40wt％，例如41～45wt％，例如46～50wt％)的所述非铝过渡金属元素以游离金属的形式存在。
在一些实施方案中，催化组合物中的游离金属的负载量定量检测方法包括以下步骤：将含有催化剂组合物的浆料进行离心处理，离心处理的转速为20000rpm，时间为 10min，采集离心后产物上清液，检测上清液中非铝过渡金属的含量值，根据该值计算游离金属在催化组合物中的含量。
在一些实施方案中，催化组合物中的交换金属的负载量等于总非铝过渡金属负载量与游离金属负载量之差。
在一些方面，本公开提供上述催化组合物的制备方法，包括：
-将第一未负载非铝过渡金属的分子筛、第一非铝过渡金属元素的前体(例如第一非铝过渡金属元素的盐)和第一溶剂(例如水)混合，获得第一悬浊液；
-将第二未负载非铝过渡金属的分子筛、第二非铝过渡金属元素的前体(例如第二非铝过渡金属元素的盐)和第二溶剂(例如水)混合，获得第二悬浊液；
-将第一悬浊液与第二悬浊液混合，获得混合浆料；
-对上一步产物进行焙烧处理。
在一些方面，本公开提供一种催化剂层，包括：
第一层，第一层含有第一分子筛，第一分子筛含有负载量为m％的第一非铝过渡金属元素；
第二层，第二层含有第二分子筛，第二分子筛含有负载量为n％的第二非铝过渡金属元素；
其中，0＜m≤n＜100；
其中，负载量以非铝过渡金属的氧化物在分子筛中的重量百分含量计；
其中，第二层在催化剂层中的位置比第一层更深；
其中，第一非铝过渡金属元素和第二非铝过渡金属元素各自独立地选自以下的一种或多种：Cu、Fe、Mn和Ce；
优选地，第一层中，第一分子筛的重量＞第二分子筛的重量≥0；
优选地，第二层中，第二分子筛的重量＞第一分子筛的重量≥0。
在一些实施方案中，第一层与第二层不重叠。
在一些实施方案中，第一层(或第二层)在催化剂层的深度以第一层(或第二层)的下表面到催化剂层的上表面的距离计算。
在一些实施方案中，第一层所含分子筛的重量与第二层所含分子筛的重量比为1～5：1～5，例如1～2：1～2，例如2：1。
在一些实施方案中，第一层与第二层的厚度比为1～5：1～5，例如2：1。
在一些方面，本公开提供一种催化装置，包括基底和上述的催化剂层，催化剂层 覆于基底的至少部分表面。
在一些实施方案中，基底具有多孔结构。
在一些实施方案中，基底具有蜂窝多孔结构。
在一些方面，本公开提供制备上述催化剂层的方法，包括：
(1)将第一未负载非铝过渡金属的分子筛、第一非铝过渡金属元素的前体(例如第一非铝过渡金属元素的盐)和第一溶剂(例如水)混合，获得第一浆料；
(2)将第二未负载非铝过渡金属的分子筛、第二非铝过渡金属元素的前体(例如第二非铝过渡金属元素的盐)和第二溶剂(例如水)混合，获得第二浆料；
(3)将第一浆料和第二浆料分别涂覆在基底上，第二浆料涂覆层比第一浆料涂覆层更靠近基底；
(4)对上一步产物进行焙烧处理。
在一些方面，本公开提供一种气体处理系统，其包含：
第一催化区，第一催化区含有第一分子筛，第一分子筛含有负载量为m％的第一非铝过渡金属元素；
第二催化区，第二催化区含有第二分子筛，第二分子筛含有负载量为n％的第二非铝过渡金属元素；
其中相对于穿过该系统的待处理气流，第一催化区位于第二催化区的上游；
其中，0＜m≤n＜100；
其中，负载量以非铝过渡金属的氧化物在分子筛中的重量百分含量计；
其中，第一非铝过渡金属元素和第二非铝过渡金属元素各自独立地选自以下的一种或多种：Cu、Fe、Mn和Ce。
在一些实施方案中，第一催化区中，第一分子筛的重量＞第二分子筛的重量≥0。
在一些实施方案中，第二催化区中，第二分子筛的重量＞第一分子筛的重量≥0。
在一些实施方案中，第一催化区所含分子筛的重量与第二催化区所含分子筛的重量的比为1～5：1～5，例如1～2：1～2，例如2：1。
在一些实施方案中，沿穿过上述系统的待处理气流的方向，第一催化区在该方向上的长度与第二催化区在该方向上的长度之比为1～5：1～5，例如2：1。
在一些方面，本公开提供制备上述气体处理系统的方法，包括
(1)将第一未负载非铝过渡金属的分子筛、第一非铝过渡金属元素的前体(例如第一非铝过渡金属元素的盐)和第一溶剂(例如水)混合，获得第一浆料；
(2)将第二未负载非铝过渡金属的分子筛、第二非铝过渡金属元素的前体(例如第二非铝过渡金属元素的盐)和第二溶剂(例如水)混合，获得第二浆料；
(3)将第一浆料和第二浆料分别涂覆在基底的第一涂覆区和第二涂覆区，其中相对于穿过该系统的待处理气流，第一涂覆区位于第二涂覆区的上游；
(4)对上一步产物进行焙烧处理。
在一些实施方案中，焙烧处理的温度为400～500℃。
在一些实施方案中，焙烧处理前还实施干燥处理的操作。
在一些实施方案中，第一非铝过渡金属元素和第二非铝过渡金属元素均为铜(Cu)元素。
在一些实施方案中，m＝n。
在一些实施方案中，m＜n。
在一些实施方案中，n-m≥0.2，例如n-m≥0.4，n-m≥0.6，例如n-m≥0.8，例如n-m≥1，例如n-m≥1.2，例如n-m≥1.4，例如n-m≥1.6，例如n-m≥1.8，例如n-m≥2.0，例如n-m≥2.2，例如n-m≥2.4。
在一些实施方案中，n-m＝0.2～5。
在一些实施方案中，m＝1～10，例如m＝2～7，例如m＝2～5，例如m＝3.2～4，例如m＝3.5～3.7。
在一些实施方案中，n＝1～10，例如m＝2～7，例如n＝2～5，例如n＝4.4～5.2，例如n＝4.7～4.9。
在一些实施方案中，第一分子筛和第二分子筛为SCR活性分子筛。
在一些实施方案中，第一分子筛和第二分子筛为小孔分子筛，优选地，小孔分子筛的平均孔尺寸为0.1～1nm，例如0.2～0.8nm，例如0.3～0.6nm，例如0.3-0.4nm。
在一些实施方案中，第一分子筛与第二分子筛具有相同的骨架结构。
在一些实施方案中，第一分子筛与第二分子筛具有不同的骨架结构。
在一些实施方案中，第一分子筛和第二分子筛各自独立地具有以下一种或多种骨架结构：AEI、AFT、AFX、BEA、CHA、EAB、EMT、ERI、FAU、GME、JSR、KFI、LEV、LTL、LTN、MFI、MOZ、MSO、MWW、OFF、SAS、SAT、SAV、SBS、SBT、SFW、SSF、SZR、TSC和WEN。
在一些实施方案中，第一分子筛和第二分子筛各自独立地具有以下一种或多种骨架结构：AEI、AFT、AFX、CHA、EAB、ERI、KFI、LEV、SAS、SAT和SAV。
在一些实施方案中，第一分子筛和第二分子筛各自独立地具有以下一种或多种骨架结构：AEI、CHA。
在一些实施方案中，第一分子筛和第二分子筛具有AEI骨架结构。
在一些实施方案中，第一分子筛具有AEI骨架结构，第二分子筛具有CHA骨架结构。
在一些实施方案中，第一分子筛为SSZ-39分子筛，第二分子筛为SSZ-13分子筛。
在一些实施方案中，第一分子筛和第二分子筛各自独立地具有10-50的二氧化硅与氧化铝之比。
在一些实施方案中，催化组合物、第一催化剂层、第二催化剂层、第一催化区或第二催化区含有氧化锆。
在一些实施方案中，催化组合物、第一催化剂层、第二催化剂层、第一催化区或第二催化区中，氧化锆的重量含量为1～20wt％，例如1～10wt％，例如2-10wt％。
在一些实施方案中，第一层和第二层之间设置有气体可通过的降温层。
在一些实施方案中，降温层不含有选择性还原反应催化剂。
在一些实施方案中，第一催化区与第二催化区之间设置有降温区。
在一些实施方案中，降温层或降温区具有多孔结构，气体穿过/流经降温层或降温区后温度得以进一步降低。
在一些方面，本公开提供催化组合物、催化剂层、催化装置或气体处理系统用于催化选择性催化还原反应(SCR)的用途，例如用于催化选择性催化还原反应(SCR)脱除氮氧化物的用途。
在一些实施方案中，第一分子筛和第二分子筛各自独立地为沸石分子筛。
在一些实施方案中，分子筛具有10至200、10至100、10至75、10至60、10至50、10～40、10～30或10～20的二氧化硅/氧化铝摩尔比(SAR)。
在一些实施方案中，催化剂层是催化浆料的涂层的烧结产物。
在一些实施方案中，催化浆料含有以下成分：分子筛、非铝过渡金属的前体(例如非铝过渡金属的盐，例如非铝过渡金属的乙酸盐或硝酸盐)和溶剂(例如水)。
在一些实施方案中，催化浆料还含有粘结剂(例如乙酸锆)。
在一些实施方案中，催化浆料还含有乙酸。
在一些实施方案中，催化浆料还含有表面活性剂。
在一些实施方案中，催化浆料具有30～50wt％的固体含量。
在一些实施方案中，催化装置上催化剂层的负载量为1～5g/inch 3，例如2～3g/inch 3，例如2.3g/inch 3。
用于本发明的催化组合物可以涂布在合适的基底上或可作为挤出型催化剂成形。在一个实施方案中，在流通型基底(即具有轴向经过整个部件的许多小的平行通道的蜂窝整料催化剂载体)或壁流过滤器，如壁流过滤器上涂布该催化剂。用于本发明的催化剂可例如作为活性涂层(washcoat)组分涂布在合适的整料基底，如金属或陶瓷流通型整料基底或过滤基底，如壁流过滤器或烧结金属或部分过滤器上。或者，用于本发明的催化剂可以直接合成到基底上。或者，本发明的催化组合物可以成形成挤出型流通催化剂。这种挤出型催化剂可成形为催化剂筒。其它形式，如丸粒、珠粒或其它成型催化剂是可行的。
用于涂布到基底上的含有本发明的分子筛负载的过渡金属催化剂的活性涂层组合物可包含本领域普通技术人员已知的其它成分。例如，这样的活性涂层组合物可另外包含选自氧化铝、二氧化硅、(非分子筛)二氧化硅-氧化铝、天然存在的粘土、TiO 2、ZrO 2、CeO 2和SnO 2及其混合物和组合的粘合剂。该催化组合物可首先作为浆料制备并作为活性涂层浆料组合物使用任何已知方法施加到基底上。
在一些实施方案中，第一催化区设置有催化剂层，催化剂层含有第一分子筛，第一分子筛含有负载量为m％的第一非铝过渡金属元素。
在一些实施方案中，第二催化区设置有催化剂层，催化剂层含有第二分子筛，第二分子筛含有负载量为n％的第二非铝过渡金属元素。
在一些实施方案中，第一层含有分子筛，以第一层的总重量为基准，分子筛的重量含量为1％以上，例如10％以上，例如20％以上，例如30％以上，例如40％以上，例如50％以上，例如60％以上，例如70％以上，例如80％以上，例如90％以上，例如100％。上述分子筛是指第一分子筛、第二分子筛或第一分子筛与第二分子筛的总和。
在一些实施方案中，第二层含有分子筛，以第二层的总重量为基准，分子筛的重量含量为1％以上，例如10％以上，例如20％以上，例如30％以上，例如40％以上，例如50％以上，例如60％以上，例如70％以上，例如80％以上，例如90％以上，例如100％。上述分子筛是指第一分子筛、第二分子筛或第一分子筛与第二分子筛的总和。
在一些实施方案中，第一催化区含有分子筛，以第一催化区的总涂层重量为基准，分子筛的重量含量为1％以上，例如10％以上，例如20％以上，例如30％以上，例如40％以上，例如50％以上，例如60％以上，例如70％以上，例如80％以上，例如90％ 以上，例如100％。上述分子筛是指第一分子筛、第二分子筛或第一分子筛与第二分子筛的总和。
在一些实施方案中，第二催化区含有分子筛，以第一层的总涂层重量为基准，分子筛的重量含量为1％以上，例如10％以上，例如20％以上，例如30％以上，例如40％以上，例如50％以上，例如60％以上，例如70％以上，例如80％以上，例如90％以上，例如100％。上述分子筛是指第一分子筛、第二分子筛或第一分子筛与第二分子筛的总和。
在一些实施方案中，第一分子筛以0.5～5g/inch 3(例如0.5～1g/inch 3、1～2g/inch 3、2～3g/inch 3、3～4g/inch 3、4～5g/inch 3，例如1.4g/inch 3)的载量(以分子筛重量计)沉积于具有400cpsi(孔每平方英寸)的孔密度和6密尔的壁厚度，直径为1英寸，长度为3英寸的蜂窝多孔陶瓷载体上，并在80,000hr -1的空速下在进料流包含500ppm NO、500ppmNH 3、10％O 2、5％H 2O、以N 2为平衡气的情况下测试时，该催化剂有效地在以下温度区间(350～400℃、400～450℃、450～500℃或350-500℃)提供80～100％(例如90～100％，例如95～100％)平均NO转化率。
在一些实施方案中，第二分子筛以0.5～5g/inch 3(例如0.5～1g/inch 3、1～2g/inch 3、2～3g/inch 3、3～4g/inch 3、4～5g/inch 3，例如0.7g/inch 3)的载量(以分子筛重量计)沉积于具有400cpsi(孔每平方英寸)的孔密度和6密尔的壁厚度，直径为1英寸，长度为3英寸的蜂窝多孔陶瓷载体上，并在80,000hr -1的空速下在进料流包含500ppm NO、500ppmNH 3、10％O 2、5％H 2O、以N 2为平衡气的情况下测试时，该催化剂有效地在以下温度区间(200-250℃或250～300℃)提供80～100％(例如90～100％，例如95～100％)平均NO转化率。
在一些实施方案中，催化组合物，催化剂层，催化装置或气体处理系统具有以下特征，分子筛以0.5～5g/inch 3(例如0.5～1g/inch 3、1～2g/inch 3、2～3g/inch 3、3～4g/inch 3、4～5g/inch 3，例如0.7g/inch 3)的载量(以分子筛重量计)沉积于具有400cpsi(孔每平方英寸)的孔密度和6密尔的壁厚度，直径为1英寸，长度为3英寸的蜂窝多孔陶瓷载体上，在80,000hr -1的空速下在进料流包含500ppm NO、500ppmNH 3、10％O 2、5％H 2O、以N 2为平衡气的情况下测试时，其有效地在以下温度区间(200-250℃、250～300℃、300～350℃、350-400℃、350～400℃、400～450℃、450～500℃或200～500℃)提供80～100％(例如90～100％，例如95～100％)平均NO转化率。
在一些实施方案中，催化组合物，催化剂层，催化装置或气体处理系统具有以下 特征，催化剂(以分子筛重量计)以0.5～5g/inch 3(例如0.5～1g/inch 3、1～2g/inch 3、2～3g/inch 3、3～4g/inch 3、4～5g/inch 3，例如0.7g/inch 3)的载量沉积于具有400cpsi(孔每平方英寸)的孔密度和6密尔的壁厚度，直径为1英寸，长度为3英寸的蜂窝多孔陶瓷载体上，在80,000hr -1的空速下在进料流包含500ppm NO、500ppmNH 3、10％O 2、5％H 2O、以N 2为平衡气的情况下测试时，其有效地在以下温度区间(200-250℃、250～300℃、300～350℃、350-400℃、350～400℃、400～450℃、450～500℃或200～500℃)提供50～100％(例如60～100％，70～100％，80～100％，90～100％，例如95～100％)平均N 2选择性。
在一些实施方案中，如果没有特别说明，分子筛是指第一分子筛或第二分子筛。
在一些实施方案中，如果没有特别说明，分子筛是指第一分子筛和第二分子筛之和。
在一些实施方案中，如果没有特别说明，非铝过渡金属元素是指第一非铝过渡金属元素或第二非铝过渡金属元素。
在一些实施方案中，如果没有特别说明，非铝过渡金属元素是指第一非铝过渡金属元素和第二非铝过渡金属元素之和。
在一些实施方案中，催化组合物/催化剂层/催化装置/气体处理系统可以处理来自燃烧过程，如来自内燃机(无论是移动还是固定的)、燃气轮机和燃煤、燃油或燃天然气的工厂或发动机的气体上进行。该方法也可用于处理来自工业工艺，如精炼、来自炼油厂加热炉和锅炉、熔炉、化学加工工业、炼焦炉、市政垃圾处理厂和焚化炉、咖啡烘焙工厂等的气体。在一个具体实施方案中，本发明的催化组合物/催化剂层/催化装置/气体处理系统用于处理来自在富燃条件下的车辆内燃机，如汽油机，或来自以液体石油气或天然气为动力的固定式发动机的废气。
术语说明：
分子筛是具有特定结构的微孔结晶固体，即通过分子四面体晶胞以规则和/或重复的相互连接方式构成骨架所形成的结晶或者伪结晶结构。在骨架中通常含有硅、铝和氧，并还可以在其空隙中含有阳离子。国际分子筛协会(IZA)结构委员会承认的独特分子筛骨架被分配三个字母的代码以指定其骨架类型。
本公开的一些分子筛符合标准《GB/T 36203-2018分子筛》。
术语“小孔分子筛”是指最大环尺寸为8的分子筛。
如本文所用，术语“催化剂”指促进反应的材料。
术语“催化组合物”指两种或更多种催化剂的组合，例如促进反应的两种不同材料的组合。催化组合物可以为洗涂层的形式。
术语氮氧化物NOx表示氮氧化物，尤其是一氧化二氮(N 2O)、一氧化氮(NO)、三氧化二氮(N 2O 3)、二氧化氮(NO 2)、四氧化二氮(N 2O 4)、五氧化二氮(N 2O 5)、过氧化氮(NO 3)。
“包含”“包括”“含有”可以是指含量大于零，例如1％以上，例如10％以上，例如20％以上，例如30％以上，例如40％以上，例如50％以上，例如60％以上，例如70％以上，例如80％以上，例如90％以上，例如100％。当含量为100％时，“包含”“包括”“含有”的含义相当于“由…构成”。
如无特别说明，％一般指重量％。
有益效果
本公开一项或多项技术方案具有以下一项或多项有益效果：
(1)催化组合物/催化剂层/催化装置/气体处理系统具有改善的DeNOx活性。
(2)催化组合物/催化剂层/催化装置/气体处理系统具有改善的抗水热老化性能。
(3)催化组合物/催化剂层/催化装置/气体处理系统制备方法简单、成本低、适合大规模应用。
(4)催化组合物中的高过渡金属负载量分子筛与低过渡金属负载量分子筛形成了协同增效的技术效果。
附图说明
图1示出一个催化装置的催化剂布局示意图；
图2示出一个催化装置的催化剂布局示意图。
具体实施方式
下面将结合实施例对本发明的实施方案进行详细描述，但是本领域技术人员将会理解，下列实施例仅用于说明本发明，而不应视为限定本发明的范围。实施例中未注明具体条件者，按照常规条件或制造商建议的条件进行。所用药品或仪器未注明生产厂商者，均为可以通过市购获得的常规产品。
以下实施例中，分子筛的铜负载量按如下公式计算：
Figure PCTCN2021131411-appb-000001
实施例1
本例中，催化装置具有如下催化剂布局：上游区3.6wt％CuO/AEI，下游区4.8wt％CuO/AEI。
图1示出实施例1的催化装置的催化剂布局示意图，如图所示，该催化装置包括第一催化区11，第一催化区11含有第一分子筛，第一分子筛含有负载量为3.6wt％的铜元素；第二催化区12，第二催化区含有第二分子筛，第二分子筛含有负载量为4.8wt％的铜元素；其中相对于穿过该系统的待处理气流6，第一催化区11位于第二催化区12的上游。
实施例1的催化装置的制备方法如下：
第一浆料的制备：将120g的乙酸铜和1000g分子筛(AEI结构)加入1000g去离子水中搅拌30分钟，随着搅拌将10g稀乙酸和150g乙酸锆粘合剂(包含30％ZrO 2)加入浆料中，再加入一定量的表面活性剂调节浆料性质，并进行研磨，最终将浆料制备至40％固体含量。
第二浆料的制备：将160g的乙酸铜和1000g分子筛(AEI结构，硅铝比16)加入1000g去离子水中搅拌30分钟，随着搅拌将10g稀乙酸和150g乙酸锆粘合剂(包含30％ZrO 2)加入浆料中，再加入一定量的表面活性剂调节浆料性质，并进行研磨，最终将浆料制备至40％固体含量。
提供一个具有400cpsi(孔每平方英寸)的孔密度和6密尔的壁厚度，直径为1英寸，长度为3英寸的蜂窝多孔陶瓷载体。沿该载体的长度方向将其划分为上游区域和下游区域，上游区域与下游区域的长度比为2:1。将第一浆料涂敷在载体上游区域，将第二浆料涂敷在载体下游区域。将涂敷的载体在120℃干燥1h，并在450℃下焙烧30分钟，在载体上形成催化剂层，获得本实施例的催化装置。
本例中，催化装置的上游区域有铜负载量3.6wt％的含铜分子筛(3.6wt％CuO/AEI)，下游区域设有铜负载量为4.8wt％的含铜分子筛(4.8wt％CuO/AEI)。催化装置上分子筛的平均的铜负载量为4wt％。催化装置的涂层负载量为2.3g/inch 3。
实施例2
催化装置具有如下催化剂布局：上游区3.6wt％CuO/AEI，下游区4.8wt％CuO/CHA。
实施例2与实施例1相似，区别在于：实施例2在制备第二浆料时，使用1000g CHA 分子筛替换实施例1中使用的1000g AEI分子筛。实施例2的第二浆料焙烧后可获铜负载量为4.8wt％的含铜分子筛(4.8wt％CuO/CHA)。其它步骤和参数与实施例1相同。
本例中，催化装置的上游区域覆有铜负载量3.6wt％的含铜分子筛(3.6wt％CuO/AEI)，下游区域覆有铜负载量为4.8wt％的含铜分子筛(4.8wt％CuO/CHA)。催化装置上分子筛的平均的铜负载量为4wt％。催化装置的涂层负载量为2.3g/inch 3。
实施例3
催化装置具有如下催化剂布局：催化剂层上层3.6wt％CuO/AEI，催化剂层下层4.8wt％CuO/AEI。
图2示出一个催化装置的催化剂布局的示意图，如图所示，该催化装置包括催化剂层2，催化剂层2包括第一层21和第二层22，第一层21含有第一分子筛，第一分子筛含有铜负载量为3.6wt％的铜元素；第二层22含有第二分子筛，第二分子筛含有铜负载量为4.8wt％的铜元素。第二层22在催化剂层2中的位置比第一层21更深，即第二层22到待处理气流6的距离比第一层21更远。
本实施例的催化装置的制备方法如下：
制备与实施例1相同的第一浆料和第二浆料。
提供一个具有400cpsi(孔每平方英寸)的孔密度和6密尔的壁厚度，直径为1英寸，长度为3英寸的蜂窝多孔陶瓷载体。将第二浆料涂敷在上述载体上，涂敷后经过120℃干燥1h，作为第二层。再将第一涂敷在下涂层上，涂敷后经过120℃干燥1h，作为第一层。将涂敷的载体在450℃下焙烧30分钟，在载体上形成催化剂层，获得实施例3的催化装置。
本例中，催化装置有双层结构的催化剂层。催化剂层的第一层(上层)有铜负载量3.6wt％的含铜分子筛(3.6wt％CuO/AEI)，催化剂层的第二层(下层)有铜负载量为4.8wt％的含铜分子筛(4.8wt％CuO/AEI)，第一层和第二层的干重比为2:1。催化装置上分子筛的平均的铜负载量为4wt％。催化装置的涂层负载量为2.3g/inch 3。
实施例4
催化装置具有如下催化剂布局：催化剂层上层3.6wt％CuO/AEI，催化剂层下层4.8wt％CuO/CHA。
本实施例的催化装置的制备方法如下：
制备与实施例2相同的第一浆料和第二浆料。
提供一个具有400cpsi(孔每平方英寸)的孔密度和6密尔的壁厚度，直径为1英寸，长度为3英寸的蜂窝多孔陶瓷载体。将第二浆料涂敷在上述载体上，涂敷后经过120℃干燥1h，作为第二层。再将第一涂敷在下涂层上，涂敷后经过120℃干燥1h，作为第一层。将涂敷的载体在450℃下焙烧30分钟，在载体上形成催化剂层，获得实施例4的催化装置。
本例中，催化装置有双层结构的催化剂层。催化剂层的第一层(上层)有铜负载量3.6wt％的含铜分子筛(3.6wt％CuO/AEI)，催化剂层的第二层(下层)有铜负载量为4.8wt％的含铜分子筛(4.8wt％CuO/CHA)，第一层和第二层的干重比为2:1。催化装置上分子筛的平均的铜负载量为4wt％。催化装置的涂层负载量为2.3g/inch 3。
实施例5
本实施例的催化装置的制备方法如下：
第一悬浊液的制备：将120g的乙酸铜和1000g的分子筛(AEI结构，硅铝比为16)加入去离子水中搅拌30分钟，随着搅拌加入10g稀乙酸和150g乙酸锆粘合剂(包含30％ZrO 2)，获得第一悬浊液。
第二悬浊液的制备：将160g乙酸铜和1000g分子筛(AEI结构，硅铝比为16)加入1000g去离子水中搅拌30分钟，随着搅拌加入10g稀乙酸和150g乙酸锆粘合剂(包含30％ZrO 2)，获得第二悬浊液。
混合浆料的制备：将第一悬浊液与第二悬浊液按干重比2:1混合，再加入一定量的表面活性剂调节浆料性质，并进行研磨，最终将浆料制备至40％固体含量。
提供一个具有400cpsi(孔每平方英寸)的孔密度和6密尔的壁厚度，直径为1英寸，长度为3英寸的蜂窝多孔陶瓷载体。将混合浆料涂覆在上述载体上，将涂敷的载体在120℃干燥1h，并在450℃下焙烧30分钟，在载体上形成催化剂层，获得实施例5的催化装置。
本例中，催化剂层含有混合的第一含铜分子筛和第二含铜分子筛，二者质量比为2:1。第一含铜分子筛是铜负载量为3.6wt％的含铜分子筛(3.6wt％CuO/AEI)，第二含铜分子筛是铜负载量为4.8wt％的含铜分子筛(4.8wt％CuO/AEI)。催化装置上分子筛的平均的铜负载量为4wt％。催化装置的涂层负载量为2.3g/inch 3。
实施例6
实施例6与实施例5相似，区别在于：实施例6在制备第二悬浊液时，使用1000g CHA分子筛替换实施例5中使用的1000g AEI分子筛。其它步骤和参数与实施例5相同。
本例中，催化剂层含有混合的第一含铜分子筛和第二含铜分子筛，二者质量比为2:1。第一含铜分子筛是铜负载量为3.6wt％的含铜分子筛(3.6wt％CuO/AEI)，第二含铜分子筛是铜负载量为4.8wt％的含铜分子筛(4.8wt％CuO/CHA)。催化装置上分子筛的平均的铜负载量为4wt％。催化装置的涂层负载量为2.3g/inch 3。
对比例1：
本实施例的催化装置的制备方法如下：
涂层浆料的制备：将133.3g的乙酸铜和1000gAEI结构的分子筛(硅铝比为16)加入1000g去离子水中搅拌30分钟，随着搅拌将加入10g稀乙酸和150g乙酸锆粘合剂(包含30％ZrO 2)，再加入一定量的表面活性剂调节浆料性质，并进行研磨，最终将浆料制备至40％固体含量。该焙烧后可获铜负载量为4.0wt％的含铜分子筛(4.0wt％CuO/AEI)
提供一个具有400cpsi(孔每平方英寸)的孔密度和6密尔的壁厚度，直径为1英寸，长度为3英寸的蜂窝多孔陶瓷载体。将混合浆料涂覆在上述载体上，将涂敷的载体在120℃干燥1h，并在450℃下焙烧30分钟，在载体上形成催化剂层，获得对比例1的催化装置。
本例中，催化剂层含有单一成分的分子筛，即铜负载量为4wt％的含铜分子筛(4wt％CuO/AEI)。催化装置的涂层负载量为2.3g/inch 3。
对比例2：
实施例2与对比例1相似，区别在于：对比例2在制备负载铜的分子筛的浆料时，使用1000g CHA分子筛替换对比例1中使用的1000g AEI分子筛。其它步骤和参数与对比例1相同。
本例中，催化剂层含有单一成分的分子筛，即铜负载量为4wt％的含铜分子筛(4wt％CuO/CHA)。催化装置的涂层负载量为2.3g/inch 3。
分析检测1：催化反应测试
提供包含上述实施例的对比例的催化装置的反应器。向反应器中通入待催化气体， 其成分如下500ppm NO、500ppmNH 3、10％O 2、5％H 2O、以N 2为平衡气。在150℃-600℃温度范围以80,000h -1的空速进行催化反应。分析催化反应前后气体的成分，根据如下公式计算NOx转化率：
Figure PCTCN2021131411-appb-000002
其中(1)表示催化反应前气体中各成分的质量，(2)表示催化反应后气体中各相应成分的质量。
分析检测2：水热老化稳定性
对新鲜的催化装置进行水热老化处理。水热老化处理条件如下：在10％H 2O含量的气氛中，在700℃的温度下，放置50小时。
然后对水热老化处理后的催化装置进行催化反应测试，测试其NOx转化率。
各实施例的低温和高温的NOx转化率见表1。
表1：
Figure PCTCN2021131411-appb-000003
表1中数据显示，分子筛布局的前后分布(即前低铜负载量，后高铜负载量)较单一涂层能够较明显提升低温和高温时的NOx转化率，而分子筛布局的上下分布(即上层低铜负载量，下层高铜负载量)些许提升了高温时的NOx转化率，而两种浆料的 均匀混合涂敷较单一涂层基本没有改善。
总之，从结果上看，前后布局(即前低铜负载量，后高铜负载量)在提高低温和高温时的NOx转化率(尤其是高温时的转化率)方面作用最为显著。
分析检测3：游离铜含量的检测
对实施例5、6和对比例1，2的混合浆料中的游离铜含量进行检测，方法如下：将混合浆料进行离心处理，离心转速为20000rpm，离心时间为10min。采集离心产物的上清液，用ICP-MS测试上清液中的铜含量，结果见表2。
表2：
Figure PCTCN2021131411-appb-000004
从表2结果可以看出，均匀混合的浆料的游离铜水平基本是比较例中单一浆料水平的平均效应，并没有由于高铜负载量和低铜负载量均匀混合的差别带来显著不同，这也可能是高铜负载量和低铜负载量均匀混合与单一浆料在NOx转化率上差别不大的原因之一。另外，从结果可以看出，AEI结构分子筛的浆料的游离铜占比相对较少，这也是AEI结构分子筛前后布局(即前低铜负载量，后高铜负载量)在实施例中表现最好的原因之一。
尽管本发明的具体实施方式已经得到详细的描述，但本领域技术人员将理解：根据已经公开的所有教导，可以对细节进行各种修改变动，并且这些改变均在本发明的保护范围之内。本发明的全部范围由所附权利要求及其任何等同物给出。

Claims (15)

  1. 一种催化组合物，包括
    第一分子筛，所述第一分子筛含有负载量为m％的第一非铝过渡金属元素；
    第二分子筛，所述第二分子筛含有负载量为n％的第二非铝过渡金属元素；
    其中，0＜m≤n＜100；
    其中，所述负载量以所述非铝过渡金属的氧化物的重量百分含量计；
    其中，所述第一非铝过渡金属元素和第二非铝过渡金属元素各自独立地选自以下的一种或多种：Cu、Fe、Mn和Ce；
    优选地，对于分子筛上负载的非铝过渡金属元素，1～50wt％的所述非铝过渡金属元素以游离金属的形式存在。
  2. 一种催化剂层，包括
    第一层，所述第一层含有第一分子筛，所述第一分子筛含有负载量为m％的第一非铝过渡金属元素；
    第二层，所述第二层含有第二分子筛，所述第二分子筛含有负载量为n％的第二非铝过渡金属元素；
    其中，0＜m≤n＜100；
    其中，所述负载量以所述非铝过渡金属的氧化物在分子筛中的重量百分含量计；
    其中，所述第二层在催化剂层中的位置比第一层更深；
    其中，所述第一非铝过渡金属元素和第二非铝过渡金属元素各自独立地选自以下的一种或多种：Cu、Fe、Mn和Ce。
  3. 根据权利要求2所述的催化剂层，其中，第一层中，第一分子筛的重量＞第二分子筛的重量≥0。
  4. 根据权利要求2所述的催化剂层，其中，第二层中，第二分子筛的重量＞第一分子筛的重量≥0。
  5. 根据权利要求2所述的催化剂层，其中，第一层和第二层之间设置有气体可通过的降温层；
    优选地，所述降温层不含选择性还原反应催化剂。
  6. 一种催化装置，包括基底和权利要求2所述的催化剂层，所述催化剂层覆于所述基底的至少部分表面；
    优选地，所述基底具有多孔结构。
  7. 一种气体处理系统，其包含：
    第一催化区，所述第一催化区含有第一分子筛，所述第一分子筛含有负载量为m％的第一非铝过渡金属元素；
    第二催化区，所述第二催化区含有第二分子筛，所述第二分子筛含有负载量为n％的第二非铝过渡金属元素；
    其中相对于穿过该系统的待处理气流，第一催化区位于第二催化区的上游；
    其中，0＜m≤n＜100；
    其中，所述负载量以所述非铝过渡金属的氧化物在分子筛中的重量百分含量计；
    其中，所述第一非铝过渡金属元素和第二非铝过渡金属元素各自独立地选自以下的一种或多种：Cu、Fe、Mn和Ce。
  8. 根据权利要求7所述的气体处理系统，其中，第一催化区中，第一分子筛的重量＞第二分子筛的重量≥0。
  9. 根据权利要求7所述的气体处理系统，其中，第二催化区中，第二分子筛的重量＞第一分子筛的重量≥0。
  10. 根据权利要求1所述的催化组合物，权利要求2所述的催化剂层，权利要求6所述的催化装置或权利要求7所述的气体处理系统，其中，m＜n；
    优选地，例如n-m≥0.2，例如n-m≥0.4，例如n-m≥0.6，例如n-m≥0.8，例如n-m≥1，例如n-m≥1.2，例如n-m≥1.4，例如n-m≥1.6，例如n-m≥1.8，例如n-m≥2.0，例如n-m≥2.2，例如n-m≥2.4。
  11. 根据权利要求1所述的催化组合物，权利要求2所述的催化剂层，权利要求6所述的催化装置或权利要求7所述的气体处理系统，其中，
    m＝1～10，例如m＝2～5，例如m＝3.2～4，例如m＝3.5～3.7；
    n＝1～10，例如n＝2～5，例如n＝4.4～5.2，例如n＝4.7～4.9。
  12. 根据权利要求1所述的催化组合物，权利要求2所述的催化剂层，权利要求6所述的催化装置或权利要求7所述的气体处理系统，其具有以下一项或多项特征：
    -第一分子筛和第二分子筛为SCR活性分子筛；
    -第一分子筛和第二分子筛为小孔分子筛，优选地，小孔分子筛的孔尺寸为0.1～1nm，例如0.3-0.4nm；
    -第一分子筛和第二分子筛各自独立地具有10-50的二氧化硅与氧化铝之比。
  13. 根据权利要求1所述的催化组合物，权利要求2所述的催化剂层，权利要求6 所述的催化装置或权利要求7所述的气体处理系统，其中，第一分子筛和第二分子筛各自独立地具有以下一种或多种骨架结构：AEI、AFT、AFX、BEA、CHA、EAB、EMT、ERI、FAU、GME、JSR、KFI、LEV、LTL、LTN、MFI、MOZ、MSO、MWW、OFF、SAS、SAT、SAV、SBS、SBT、SFW、SSF、SZR、TSC和WEN；
    优选地，第一分子筛和第二分子筛各自独立地具有以下一种或多种骨架结构：AEI、AFT、AFX、CHA、EAB、ERI、KFI、LEV、SAS、SAT和SAV；
    优选地，第一分子筛和第二分子筛各自独立地具有以下一种或多种骨架结构：AEI、CHA；
    优选地，第一分子筛和第二分子筛具有AEI骨架结构；
    优选地，第一分子筛具有AEI骨架结构，第二分子筛具有CHA骨架结构；
    优选地，第一分子筛为SSZ-39分子筛，第二分子筛为SSZ-13分子筛。
  14. 根据权利要求1所述的催化组合物，权利要求2所述的催化剂层，权利要求6所述的催化装置或权利要求7所述的气体处理系统，其中还含有氧化锆；
    优选地，氧化锆在其中的含量为1～20wt％，例如2-10wt％。
  15. 权利要求1所述的催化组合物，权利要求2所述的催化剂层，权利要求6所述的催化装置或权利要求7所述的气体处理系统用于催化选择性催化还原反应的用途。
PCT/CN2021/131411 2020-12-28 2021-11-18 一种催化组合物、催化剂层、催化装置和气体处理系统 WO2022142836A1 (zh)

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CN102215960A (zh) * 2008-11-06 2011-10-12 巴斯夫公司 具有低二氧化硅与氧化铝比率的菱沸石催化剂
CN102821847A (zh) * 2009-11-30 2012-12-12 约翰逊马西有限公司 处理瞬时nox排放的催化剂
EP2857084A1 (fr) * 2013-10-07 2015-04-08 Peugeot Citroën Automobiles Sa Dispositif de traitement des gaz d' échappement
CN105264188A (zh) * 2013-04-24 2016-01-20 庄信万丰股份有限公司 包括催化型分区涂覆的过滤器基底的强制点火发动机和排气系统
CN107106982A (zh) * 2014-11-19 2017-08-29 庄信万丰股份有限公司 组合 scr 与 pna 用于低温排放控制
CN110114130A (zh) * 2016-12-05 2019-08-09 巴斯夫公司 用于氧化NO、氧化烃类、氧化NH3和选择性催化还原NOx的四功能催化剂

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102215960A (zh) * 2008-11-06 2011-10-12 巴斯夫公司 具有低二氧化硅与氧化铝比率的菱沸石催化剂
CN102821847A (zh) * 2009-11-30 2012-12-12 约翰逊马西有限公司 处理瞬时nox排放的催化剂
CN105264188A (zh) * 2013-04-24 2016-01-20 庄信万丰股份有限公司 包括催化型分区涂覆的过滤器基底的强制点火发动机和排气系统
EP2857084A1 (fr) * 2013-10-07 2015-04-08 Peugeot Citroën Automobiles Sa Dispositif de traitement des gaz d' échappement
CN107106982A (zh) * 2014-11-19 2017-08-29 庄信万丰股份有限公司 组合 scr 与 pna 用于低温排放控制
CN110114130A (zh) * 2016-12-05 2019-08-09 巴斯夫公司 用于氧化NO、氧化烃类、氧化NH3和选择性催化还原NOx的四功能催化剂

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