CN1091396C - Catalyst for use in waste gas purification - Google Patents
Catalyst for use in waste gas purification Download PDFInfo
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- CN1091396C CN1091396C CN00104411A CN00104411A CN1091396C CN 1091396 C CN1091396 C CN 1091396C CN 00104411 A CN00104411 A CN 00104411A CN 00104411 A CN00104411 A CN 00104411A CN 1091396 C CN1091396 C CN 1091396C
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Abstract
The present invention relates to a catalyst for purifying exhaust gas, which has the technical scheme that a catalyst carrier adopts a cordierite honeycomb carrier which is coated with oxide containing A (one or more of Ca, Ba 2, Sr and M g), B (one or two kinds of La and Ce) and C (two or three kinds of Zr, Y and Si) or activated alumina coating layers; the active component of the catalyst is composed of rare earth oxide, alkaline earth oxide, transition metal oxide and noble metal. The catalyst has the characteristics that the resistance temperature can reach 1200 DEG C., and the initiation temperature of the catalyst is below 200 DEG C. In addition, the catalyst has large specific surface area and superior durability, and the oxide coating is not easy to fall off. The catalyst can be used for purifying industrial waste gas and automobile exhaust gas containing carbon monoxide, hydrocarbon and oxynitride.
Description
The present invention relates to a kind of Catalysts and its preparation method that is used for purifying exhaust air.More particularly, the present invention relates to a kind of Catalysts and its preparation method that is used for purifying automobile tail gas and industrial waste gas.
Along with developing of automobile industry, the atmosphere pollution of the atmosphere pollution that vehicle exhaust caused, particularly city is very serious.In recent years, the vehicle guaranteeding organic quantity of China is keeping growth faster, and the pollutant of motor vehicle emission has reached very high ratio to the contribution of urban atmospheric pollution.The vehicle exhaust pernicious gas is mainly by CO, NO
x, composition such as CH constitutes.These gases are very big to the harm of health and PE.At present, a urgent task of the control automobile pollution that causes having become the pollution control in city.
Existing at present many research and patents about the cleaning catalyst for tail gases of automobiles aspect, as CN85109694, CN1119127A, CN1072107, US4820678, US5164350, US5182249 etc., these patents can be controlled the discharging of CO, CH, NO effectively.People have higher requirement to cleaning catalyst for tail gases of automobiles, and along with the development of highway construction, the raising of the speed of a motor vehicle requires three-way catalyst to have stable high temperature resistant property.In addition, a large amount of vehicle exhausts is discharged when starting, and the initiation temperature of reduction catalyst becomes a very important direction in the present three-way catalyst development work.
At present, generally adopt active A l during the support modification of exhaust gas purifying catalyst
2O
3, still well-known, along with temperature raises, aluminium oxide can undergo phase transition, and is shown below:
Along with the generation of phase transformation, the specific area of aluminium oxide also can reduce thereupon, thereby causes the catalyst activity component, and particularly the noble metal active component is built up and is wrapped, and causes catalyst activity reduction, the lost of life.Therefore modified aluminas makes it at high temperature still have high-specific surface area, becomes the key in the tai-gas clean-up catalyst development work.Wherein introduced the modification of phosphate in the United States Patent (USP) 5260241 to aluminium oxide.Among the CN1160599A, use the modified oxidized aluminum slurry of ferrochrome lignosulfonate, thereby reach modification aluminum oxide coating layer.
The purpose of this invention is to provide a kind of three-way catalyst, make it have very high catalytic conversion efficiency, good anti-lead, sulfur poisoning performance, and long endurance quality the time, improve the high temperature resistant property of catalyst emphatically, reduce the initiation temperature of catalyst.
The carrier that catalyst of the present invention is selected for use is the cordierite honeycomb carrier, the active oxidation aluminium lamination by three kinds of oxides of ABC and carbonate modification is contained on the surface, A is at least a Ca, Ba, Sr, the oxide of Mg or carbonate, B are La, the mixed oxide of Ce or carbonate, C are: Zr, Y, at least two kinds mixed oxide among the Si.
The weight of the active oxidation aluminium lamination of modification is the 8-25% of vehicle weight, and wherein, A is the 0.5-8% of aluminum oxide coating layer mass fraction, and B is the 3-35% of aluminum oxide coating layer mass fraction, and C is the 0.1-5% of aluminum oxide coating layer mass fraction.
Wherein, the mole ratio of Ce among the B: La is 2-4: 1.
Catalyst activity component of the present invention is made up of two-layer:
Ground floor is made up of composite oxides DEF, and its content is the 0.1-10% of catalyst quality mark.
D selects one kind of La, Ce for use; E selects one or both of Mg, Ca, Sr for use; F is made up of the oxide of the oxide of Mn and at least a Cu, Cr, Ni, Fe.
D/E=0.1-7 wherein, E/F=0.1-2.
The second layer is made up of precious metals pt-Rh-Pd, and the total content of noble metal is the 0.001-1.5% of catalyst quality mark.In the noble metal component, the Pt/Rh mass fraction is than being 3-10: 1.
Catalyst of the present invention can also be realized by following measure:
The carrier that catalyst is selected for use is the cordierite honeycomb carrier, the active oxidation aluminium lamination by three kinds of oxides of ABC and carbonate modification is contained on the surface, A is at least a Ca, Ba, Sr, the oxide of Mg or carbonate, B are La, the mixed oxide of Ce or carbonate, C are: Zr, Y, at least two kinds mixed oxide among the Si.
The weight of the active oxidation aluminium lamination of modification is the 8-25% of vehicle weight, and wherein, A is the 0.5-8% of aluminum oxide coating layer mass fraction, and B is the 3-35% of aluminum oxide coating layer mass fraction, and C is the 0.1-5% of aluminum oxide coating layer mass fraction.
Wherein, the mole ratio of Ce among the B: La is 2-4: 1.
Catalyst activity component of the present invention is made up of two-layer:
Ground floor is made up of composite oxides DEF, and its content is the 0.1-10% of catalyst quality mark.
D selects one kind of La, Ce for use; E selects one or both of Mg, Ca, Sr for use; F is made up of the oxide of the oxide of Mn and at least a Cu, Cr, Ni, Fe.
D/E=0.1-7 wherein, E/F=0.1-2.
The second layer, noble metal adopt single Pd, and the total content of noble metal is the 0.001-1.5% of catalyst quality mark, and the oxide of answering at least a La, Mo, Zr is as auxiliary agent, and auxiliary agent content is 1-10 times of noble metal mass fraction.
Preparation of catalysts method of the present invention may further comprise the steps:
1). the preparation of cordierite honeycomb carrier surface modified active alumina layer
A. prepare the glue of modified aluminas: the solution of the aluminum nitrate of the 1-3M for preparing in advance, the salt with the solubility of auxiliary agent joins in the solution simultaneously.The aluminium oxide dry powder or the boehmite that will contain oxide and carbonate auxiliary agent join in the solution by a certain percentage, and the pH value of modulation slurries obtains the modified aluminas glue to 2.0-4.5.
B. adopt the method for dip-coating or spraying to coat the cordierite carrier surface above-mentioned glue, drying after roasting, can form the aluminum oxide coating layer of modification on carrier again.
2). the preparation of catalyst activity component
A. prepare the solution that contains the active component soluble-salt in proportion.But soluble-salt is the metallic compound that thermal decomposition forms metal oxide required in the active component, and what preferentially select for use is nitrate, carbonate, acetate, chloride.
B. adopt infusion process or spraying process, respectively two-layer active component is coated with built in carrier surface in two steps.
C. coat at every turn finish after, dry, roasting.
D. if adopt chloride, then need to handle, obtain finished catalyst with the reducibility gas reduction that contains hydrogen, carbon monoxide, hydrocarbon compound.The catalyst reduction temperature is 200-700 ℃.
In the above-mentioned Preparation of catalysts, dry run needs 8-12 hour.Baking temperature is controlled at 50-150 ℃.
Roasting process generally needs 2-8 hour, is advisable with 4-6 hour, and sintering temperature generally is controlled at 400-850 ℃, is advisable with 500-750 ℃.
The reaction medium of catalyst of the present invention is the gas that contains CO, CH, Nox and molecular oxygen, can contain CO2, water vapour and other inert gases.By under standard temperature and pressure (STP), calculate gas space velocity be preferably: during 5000-100000
-1
Ternary of the present invention meets catalyst commonly used in metal oxide catalyst and the prior art and compares and have following advantage:
1. because the oxide of ABC three dvielements and carbonate to the modification of activated alumina, make aluminum oxide coating layer have better heat resistance, the high temperature sintering of coating can be stoped effectively and the specific area that causes reduces, the reduction of catalytic activity.Catalyst 1000 ℃ 12 hours aging after, the specific area of coating still reaches 120m2/g, has guaranteed that the high temperature of catalyst uses active.
2. catalyst low-temperature activity is good, the T of CO, CH, NOx
50All dropped to below 200 ℃ the emission status of tail gas when helping to improve engine cold-start.
Ternary composite metal oxide catalyst of the present invention will be further specified by following embodiment.
Embodiment 1.
The preparation method of aluminum oxide coating layer.
Take by weighing 2001 gram aluminum nitrates, 120 gram cerous nitrates are dissolved in 2000 ml distilled waters, get 1000 milliliters of this solution, add 12 gram calcium nitrate, 15 gram lanthanum nitrates, 8 gram zirconium nitrates, 2 gram yttrium nitrates, after the stirring and dissolving, add 150 gram boehmites and 10 gram silicon tetrachlorides again, after stirring, the pH value of reconciling slurry with nitric acid is 3.4, promptly gets the A1 glue.
Get 1000 milliliters of above-mentioned aluminum nitrate, cerous nitrate solutions in addition again, add 11 gram magnesium nitrates, 15 gram lanthanum nitrates, 8 gram zirconium nitrates and 2 gram yttrium nitrates, after stirring, add 150 gram boehmites and 20 gram brium carbonates again, after stirring, the pH value of reconciling slurry with nitric acid is 3.4, promptly gets the A2 glue.
The cordierite honeycomb carrier coats the active oxidation aluminized coating through dip coating.After carrier put into glue 5-10 minute, take out, blow away slurries unnecessary in the duct with compressed air, in 100 ℃ of dryings, dip-coating once promptly gets the carrier for preparing after dry, the roasting again.According to the difference of glue, prepared three kinds of different carriers, 400 grams respectively, glue A1-A1 makes carrier X, and glue A1-A2 makes carrier Y, and glue A2-A2 makes carrier Z.
Embodiment 2-5, the preparation method of catalyst activity component.
Embodiment 2. gets 400 milliliters of 1M manganese nitrate solutions, 370 milliliters of 0.8M lanthanum nitrate hexahydrates, 40 milliliters of 0.4M strontium nitrate solutions, 50 milliliters of 0.8M nickel nitrate solutions, the palladium nitrate solution of 99 milliliters of 16mg/ml, the mixed maceration extract that gets.Take by weighing carrier " X " 100 grams, behind 50 ℃ of this solution of dipping, 80 ℃ of dryings.After 600 ℃ of roastings, promptly make catalyst 1#.
Embodiment 3. takes by weighing carrier " Z " 100 grams, behind 50 ℃ of this solution of dipping, 80 ℃ of dryings.After 600 ℃ of roastings, promptly make catalyst 2#.
Embodiment 4. usefulness 100 gram carriers " Y " flood by 400 milliliters of 1M manganese nitrate solutions 370 milliliters of 0.8M lanthanum nitrate hexahydrates, 40 milliliters of 0.4M magnesium nitrate solutions, 50 milliliters of 0.8M nickel nitrate solutions, the maceration extract of the iron nitrate solution preparation of 55 milliliters of 0.5M is after the drying, 500 ℃ of roastings.And then the dipping contain palladium 1.8mg/ml, contain the solution of Pt, Rh (3: 1) 0.40mg/ml, after the drying, at 600 ℃ of roasting 4-6 hours, with hydrogen 400 ℃ the reduction 4 hours, promptly get catalyst 3#
Embodiment 5 usefulness 100 gram carriers " Y " flood by 400 milliliters of 0.8M manganese nitrate solutions, 200 milliliters of 0.75M magnesium nitrate solutions, and 50 milliliters of 0.8M nickel nitrate solutions, the maceration extract of the cerous nitrate solution preparation of 55 milliliters of 0.5M is after the drying, 500 ℃ of roastings.And then flood the solution that contains Pt, Rh (5: 1) 1.8mg/ml, after the drying,, 400 ℃ of reduction 4 hours, promptly get catalyst 4# with hydrogen at 600 ℃ of roasting 4-6 hours
6. examples of embodiment illustrate that catalyst provided by the invention is in breadboard evaluation result.
Above-mentioned catalyst is made into, and diameter is 10 millimeters, and length is 20 millimeters small cylinder, and the internal diameter of packing into is in 12 millimeters the quartz reactor, with the heating furnace reactor of heating.Reactor feed gas consists of: CO9000ppm, CH500ppm, CO
211000ppm, NO
x800ppm, O
2500ppm, this unstripped gas be with air speed 10000-40000h-1, by reaction tube, and since 100 ℃, 30 ℃ of every risings, after the stable reaction, CO, CH, NOX content in the tail gas in assaying reaction device exit calculate the gas conversion ratio.With conversion ratio reaction temperature is mapped, try to achieve conversion ratio and be 50% o'clock reaction temperature T50, this value shows the cryogenic property of catalyst.Listed the reaction result of above-mentioned catalyst in the table.
Table. the reaction result of catalyst
| Catalyst | T50，℃ | 300 ℃, conversion ratio % | ||||
| CO | CH | NO x | CO | CH | NO x | |
| 1# | 205 | 218 | 220 | 94.51 | 93.22 | 90.32 |
| 2# | 210 | 221 | 220 | 93.43 | 90.78 | 91.22 |
| 3# | 190 | 198 | 195 | 96.91 | 93.11 | 92.71 |
| 4# | 185 | 197 | 193 | 99.01 | 95.21 | 93.53 |
Claims (5)
1. purifying exhaust air catalyst that is used for is characterized in that:
The carrier that catalyst is selected for use is the cordierite honeycomb carrier, the active oxidation aluminium lamination by three kinds of oxides of ABC and carbonate modification is contained on the surface, A is at least a Ca, Ba, Sr, the oxide of Mg or carbonate, B are La, the mixed oxide of Ce or carbonate, C are: Zr, Y, at least two kinds mixed oxide among the Si;
The weight of the active oxidation aluminium lamination of modification is the 8-25% of vehicle weight, and wherein, A is the 0.5-8% of aluminum oxide coating layer mass fraction, and B is the 3-35% of aluminum oxide coating layer mass fraction, and C is the 0.1-5% of aluminum oxide coating layer mass fraction;
Wherein, the mole ratio of Ce among the B: La is 2-4: 1;
The catalyst activity component is made up of two-layer:
Ground floor is made up of composite oxides DEF, and its content is the 0.1-10% of catalyst quality mark;
D selects one kind of La, Ce for use; E selects one or both of Mg, Ca, Sr for use; F is made up of the oxide of the oxide of Mn and at least a Cu, Cr, Ni, Fe;
D/E=0.1-7 wherein, E/F=0.1-2;
The second layer is made up of the Pt-Rh-Pd noble metal, and the total content of noble metal is the 0.001-1.5% of catalyst quality mark; In the noble metal component, the Pt/Rh mass fraction is than being 3-10: 1.
2. catalyst that is used for purifying exhaust air is characterized in that:
The carrier that catalyst is selected for use is the cordierite honeycomb carrier, the active oxidation aluminium lamination by three kinds of oxides of ABC and carbonate modification is contained on the surface, A is at least a Ca, Ba, Sr, the oxide of Mg or carbonate, B are La, the mixed oxide of Ce or carbonate, C are: Zr, Y, at least two kinds mixed oxide among the Si;
The weight of the active oxidation aluminium lamination of modification is the 8-25% of vehicle weight, and wherein, A is the 0.5-8% of aluminum oxide coating layer mass fraction, and B is the 3-35% of aluminum oxide coating layer mass fraction, and C is the 0.1-5% of aluminum oxide coating layer mass fraction;
Wherein, the mole ratio of Ce among the B: La is 2-4: 1;
The catalyst activity component is made up of two-layer:
Ground floor is made up of composite oxides DEF, and its content is the 0.1-10% of catalyst quality mark;
D selects one kind of La, Ce for use; E selects one or both of Mg, Ca, Sr for use; F is made up of the oxide of the oxide of Mn and at least a Cu, Cr, Ni, Fe;
D/E=0.1-7 wherein, E/F=0.1-2;
The second layer, noble metal adopt single Pd, and the total content of noble metal is the 0.001-1.5% of catalyst quality mark, and the oxide of answering at least a La, Mo, Zr is as auxiliary agent, and auxiliary agent content is 1-10 times of noble metal mass fraction.
3. according to claim 1 or 2 described Preparation of catalysts methods, it is characterized in that in turn including the following steps:
1). the preparation of cordierite honeycomb carrier surface modified active alumina layer
A. prepare the glue of modified aluminas: the solution of the aluminum nitrate of the 1-3M for preparing in advance, the salt with the solubility of auxiliary agent joins in the solution simultaneously; The aluminium oxide dry powder or the boehmite that will contain oxide and carbonate auxiliary agent join in the solution by a certain percentage, and the pH value of modulation slurries obtains the modified aluminas glue to 2.0-4.5;
B. adopt the method for dip-coating or spraying to coat the cordierite carrier surface above-mentioned glue, drying after roasting, can form the aluminum oxide coating layer of modification on carrier again;
2). the preparation of catalyst activity component
A. prepare the solution that contains the active component soluble-salt in proportion; What soluble-salt was selected for use is nitrate, carbonate, acetate, chloride;
B. adopt infusion process or spraying process, respectively two-layer active component is coated with built in carrier surface in two steps;
C. coat finish after, dry, roasting;
D. if adopt chloride, handle, obtain finished catalyst with the reducibility gas reduction that contains hydrogen, carbon monoxide, hydrocarbon compound; The catalyst reduction temperature is 200-700 ℃.
4. by the described Preparation of catalysts method of claim 3, it is characterized in that dry run 6-12 hour, baking temperature is controlled at 60-120 ℃.
5. by the described Preparation of catalysts method of claim 3, it is characterized in that roasting process 2-8 hour, sintering temperature is controlled at 400-850 ℃.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN00104411A CN1091396C (en) | 2000-06-21 | 2000-06-21 | Catalyst for use in waste gas purification |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN00104411A CN1091396C (en) | 2000-06-21 | 2000-06-21 | Catalyst for use in waste gas purification |
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| CN1277892A CN1277892A (en) | 2000-12-27 |
| CN1091396C true CN1091396C (en) | 2002-09-25 |
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| CN00104411A Expired - Fee Related CN1091396C (en) | 2000-06-21 | 2000-06-21 | Catalyst for use in waste gas purification |
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| CN1171007C (en) * | 2001-11-22 | 2004-10-13 | 李树胜 | Purifying system for high power output and low-temp tail gas discharge of IC engine |
| CN1311903C (en) * | 2004-12-09 | 2007-04-25 | 天津化工研究设计院 | Method for preparing rare earth base high-performance three-effect catalyst |
| CN100364662C (en) * | 2005-08-29 | 2008-01-30 | 浙江大学 | Process for preparing rare-earth composite porous aluminium oxide loaded Pd catalyst |
| JP4831753B2 (en) * | 2006-06-13 | 2011-12-07 | 株式会社豊田中央研究所 | Exhaust gas purification catalyst |
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| CN106040281A (en) * | 2016-06-08 | 2016-10-26 | 安徽新态环保科技有限公司 | Nanometer repairing agent for three-way catalytic converters |
| CN106732529A (en) * | 2016-11-09 | 2017-05-31 | 上海派特贵金属环保科技有限公司 | A kind of SCR denitration and preparation method thereof |
| CN111315476A (en) * | 2017-11-13 | 2020-06-19 | 三井金属矿业株式会社 | Nitrogen oxide storage material and exhaust gas purification catalyst |
| CN111054389B (en) * | 2019-11-25 | 2023-06-30 | 李俊鸿 | Methanol low-temperature heating catalyst and preparation method thereof |
| CN111111642B (en) * | 2019-12-26 | 2023-01-24 | 山东国瓷功能材料股份有限公司 | Denitration catalyst and preparation method and application thereof |
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| US4820678A (en) * | 1986-07-30 | 1989-04-11 | Beijing Polytechnic University | Method for preparing rare earth metal catalysts with honeycomb-like alloy supports and catalysts obtained thereby |
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