WO2022142836A1 - Composition catalytique, couche de catalyseur, dispositif catalytique et système de traitement de gaz - Google Patents

Composition catalytique, couche de catalyseur, dispositif catalytique et système de traitement de gaz 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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Chinese (zh)
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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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    • 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

L'invention concerne une composition catalytique, une couche de catalyseur, un dispositif catalytique et un système de traitement de gaz. La composition catalytique, la couche de catalyseur et le système de traitement de gaz présentent une activité SCR améliorée.
PCT/CN2021/131411 2020-12-28 2021-11-18 Composition catalytique, couche de catalyseur, dispositif catalytique et système de traitement de gaz WO2022142836A1 (fr)

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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
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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