CN1509813A - Oxygen-enriched tail gas nitrogen oxide purifying catalyst - Google Patents
Oxygen-enriched tail gas nitrogen oxide purifying catalyst Download PDFInfo
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- CN1509813A CN1509813A CNA021579172A CN02157917A CN1509813A CN 1509813 A CN1509813 A CN 1509813A CN A021579172 A CNA021579172 A CN A021579172A CN 02157917 A CN02157917 A CN 02157917A CN 1509813 A CN1509813 A CN 1509813A
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Abstract
A catalyst of removing the NOx, residual organic substance and CO from the oxygen-enriched tail gas from engine contains the porous inorganic carrier, silver, noble metal chosen from Au, Pt, Pd, Ph, Ir and Ru, and other metal chosen from Fe, Cu, Ti, Zr, Ba, Sn, W, Zn, Mo, Ce, Cs, La and Ca.
Description
Technical field
The present invention is used for the nitrogen oxide of purification of exhaust gases of internal combustion engines, particularly utilizes limited carbon monoxide and organic matter selective reducing nitrogen oxide in oxidizing atmosphere, and catalyst also has higher nitrogen oxide reducing activity under lower temperature.
Technical background
These are different with the three-way catalyst that generally is used at present to purify gasoline engine tail gas.The use of three-way catalyst is to be based upon the ratio of strict control petrol engine air and fuel near theoretical air-fuel ratio (stoichiometric proportion), and remaining oxygen content is seldom in the tail gas at this moment.Its mechanism of action is to make carbon monoxide and organic matter as reducing agent nitrogen oxides reduction (NO by catalyst
x) become nitrogen, and the remaining carbon monoxide of catalytic oxidation becomes carbon dioxide and water with organic matter.Nearly all new product gasoline car (not containing lean-burn gasoline motor car) all is equipped with three-way catalyst at present, and what form sharp contrast therewith is that diesel vehicle is not taked similar control techniques basically.The practical air-fuel ratio of diesel engine is much larger than its chemically correct fuel, belong to lean combustion engine, in the tail gas carbon monoxide and organic content seldom, but oxygen content is tens times of gasoline engine, can reach 15% volume ratio, clearly three-way catalyst is not suitable for the operating mode of diesel engine.Diesel engine becomes a main flow direction of following motor vehicle development with its good dynamic property and economy, diesel generation and electricity-Re one residential quarter facility is also more prevalent, yet its discharged nitrous oxides pollution that does not add processing is restricting development of diesel.
Up to the present, for the Rarefied combustion tail gas catalysis and purification technology of nitrogen oxide in diesel engine and the gasoline engine tail gas particularly, the catalyst of studying can be divided into zeolite, load type metal or metal oxide and the carried noble metal three major types of ion-exchange, and reducing agent mainly contains Ammonia, low-carbon alkene, alkane, alcohol, ketone and ether etc.At present, the subject matter that catalyst in the research exists is, zeolite catalyst is to steam and sulfur dioxide poisoning, and hydrothermal stability is poor; The noble metal catalyst poor selectivity, and the active temperature scope is narrow, and most of reducing agent loses the ability of nitrogen oxides reduction at the high-temperature region oxidizing fire; Load type metal or metal oxide catalyst low temperature active when making reducing agent with organic matters such as low-carbon alkene, alkane is still waiting to improve.For example, we had applied for the patent (application number: 02100669.5) of silver catalyst in the past, this catalyst has good anti-sulfur dioxide poisoning ability and hydrothermal stability, and with third rare be in the scope of 400-550 ℃ of simulated exhaust gas temperature of reducing agent, average transformation efficiency of the oxides of nitrogen is 57.7%, but the low temperature active of silver catalyst is relatively poor.
Summary of the invention
The present invention is directed to the problems referred to above, silver catalyst is improved, a kind of particularly diesel engine vent gas oxynitrides (NO of combustion tail gas that is used under the excess oxygen is provided
x) the catalyst of catalytic purification, have good cryogenic nitrogen oxide reducing activity with respect to silver catalyst.
The effect of invention
The present invention is fully taking into account on the basis of previous studies, is carrying out the result of big quantity research.The catalyst that is provided is oxygen content (for example 10% volume) oxygen content when burning far above stoichiometric proportion in tail gas, and still nitrogen oxide is had very high reducing activity under the water vapor conditions of 10% volume, particularly than the activity under the low exhaust gas temperature.In addition, sulfur dioxide in the tail gas and phosphorus composition there is very strong anti-poisoning capability.
Catalyst of the present invention can be loaded on the same porous inorganic thing carrier simultaneously or with any sequencing by other metal components of the noble metal component of the silver components of 0.1-10% (metallic element weight scaled value), 0.01-1.5% (metallic element weight scaled value) and 1.0-25% (metallic element weight scaled value) and constitute, and also can load on respectively on the different porous inorganic thing carriers to constitute catalyst by mixing.Aforementioned noble metal component is at least a in noble metal group gold, platinum, palladium, rhodium, iridium, the ruthenium, and aforementioned other metal components can be at least a in metal group iron, copper, titanium, zirconium, barium, tin, tungsten, zinc, molybdenum, cerium, caesium, lanthanum, the calcium.
Aforesaid catalyst, when silver components during less than 0.1% (metallic element weight scaled value), the activity of such catalysts particularly conversion ratio of cryogenic nitrogen oxide can reduce.And silver components can reduce the pyrolytic conversion rate of nitrogen oxide during greater than 10% (metallic element weight scaled value).The indication silver components can be the oxide of silver and silver and the form of any inorganic salts and do not change its effect, it is characterized in that silver components has the particle diameter of average 5-1000 nanometer on porous inorganic thing carrier, is preferably average 10-300 nanometer.Aforesaid catalyst, when noble metal component during less than 0.01% (metallic element weight scaled value), the activity of such catalysts particularly conversion ratio of cryogenic nitrogen oxide can reduce.And noble metal component is during greater than 1.5% (metallic element weight scaled value), can preferential combustion and reduce the pyrolytic conversion rate of nitrogen oxide as the organic matter of reducing agent.Aforementioned noble metal component can be the form of the oxide of this noble metal and this noble metal and any inorganic salts and do not change its effect.It is characterized in that silver components has the particle diameter of average 5-300 nanometer on porous inorganic thing carrier, be preferably average 10-50 nanometer.Other metal components of aforementioned 1.0-25% (metallic element weight scaled value) can be the forms of the oxide of this metal and this metal and any inorganic salts and do not change its effect, it act as the co-catalyst or second carrier, looks application and condition and adjusts.The porous inorganic thing carrier of catalyst can be alundum (Al, silica, zeolite, sepiolite, titanium dioxide, zirconium dioxide, zinc oxide, magnesia, tin ash one or more hopcalites or its composite oxides, porous carbon material wherein.Aforesaid porous inorganic thing carrier should have 10 meters squared per gram or bigger specific area, is preferably 30 meters squared per gram or bigger specific area.
According to the present invention, component, noble metal component and other metal components of silver can be by usefulness soluble compound water solution separately with well-known infusion process, and the precipitation method or sol-gel process are deposited on the aforesaid porous inorganic thing carrier.During such as the use infusion process, selected porous inorganic thing carrier can be soaked in silver, noble metal and other metals soluble compounds aqueous solution separately, stirred 1-24 hour, 80-150 ℃ of drying, interim ground is warming up to 700 ℃ from 100 ℃ in air or nitrogen or hydrogen or vacuum.The granular size of component, noble metal component and other metal components of silver can be controlled by adjusting factors such as temperature, time and atmosphere.According to the present invention, also can one or both metal components be carried on the porous inorganic thing carrier by preceding method any order, press with other metal components of quadrat method load then.According to the present invention, component, noble metal component and other metal components of silver also can load on respectively on the different porous inorganic thing carriers and constitute catalyst by mixing.
Aforesaid catalyst, preferably be coated on the wall surface of circulation passage of pottery or metal honeycomb with the form of coating, this one-piece type catalyst has the passage of the parallel circulation of many tail gas, and vapour lock is very little, can be applicable to handle diesel engine vent gas or gasoline engine tail gas.The hole density of preferred honeycomb is the 100-400/ square inch.Catalyst is coated on these carrier structures with the concentration of 30-300 gram/every liter of carrier structure.According to different needs, other structures also can be as the structural carrier of catalyst as metallic sieve or open-celled foams.Also catalyst can be made spherical or tabular use.
Be suitable for the tail gas source and comprise Diesel engine, fixing or motor-driven burner such as lean-burn gasoline engine and natural gas engine.It is characterized in that, when the content of oxygen in tail gas catalyst when equivalent burns still effective, but when imperfect combustion hydrocarbon and carbon monoxide content are not enough to be used for nitrogen oxides reduction under the above-mentioned lean burn situation, need to add hydrocarbon/or oxygen-bearing organic matter/or the mixture of hydrocarbon and oxygen-bearing organic matter as reducing agent with nitrogen oxides reduction.
Oxygen content is higher than that the purification of nitrogen oxides method is in the combustion tail gas of stoichiometric proportion when burning oxygen content, aforesaid catalyst can be placed aforesaid exhaust pipe way, add in the upstream of catalyst hydrocarbon/or oxygen-bearing organic matter/or the mixture and the tail gas of hydrocarbon and oxygen-bearing organic matter mix, gaseous mixture is contacted with catalyst at 150-600 ℃, thus make nitrogen oxide and hydrocarbon/or oxygen-bearing organic matter/or the mixture reaction of hydrocarbon and oxygen-bearing organic matter be reduced into nitrogen.Preferred exhaust temperature scope is 250-550 ℃.Unnecessary reducing agent is oxidized to carbon dioxide and water under the effect of catalyst.The method of the interpolation of above-mentioned reducing agent (gaseous state or liquid state) can be carried out with the form of spraying the upstream of catalyst in exhaust pipe.Also above-mentioned reducing agent (gaseous state or liquid state) can be injected in the combustion chambers of internal combustion engines, utilize the remaining component of burning to make reducing agent and contact nitrogen oxide in the reduction tail gas with catalyst.The air/fuel ratio that can also adjust internal combustion engine makes and contains more unburned hydrocarbons and oxygen-bearing organic matter in the tail gas, contacts nitrogen oxide in the reduction tail gas with catalyst.Relatively above several method can obtain most economical and effective Rarefied combustion tail gas nitrogen oxide purification method.
In order to be illustrated more clearly in the present invention, enumerate following examples, but it there is not any restriction to scope of the present invention.
Embodiment 1
(particle diameter is less than 120 orders for 100 gram γ-alundum (Al powder, specific area: be not less than 250 meters squared per gram) be soaked in decide in the mixed aqueous solution of silver nitrate, platinum chloric acid, ferric nitrate of concentration, stirred 1 hour, after 90 ℃ of dryings, in air, interimly be warming up to 700 ℃ from 100 ℃, kept 3 hours, reduce to room temperature, it is standby to get the 0.5-1.0mm particle after the pulverizing, for implementing catalyst A.The silver components load capacity of manufactured goods catalyst is 5.0% (metallic element weight scaled value), and platinum component load capacity is 0.25% (metallic element weight scaled value), and iron component load capacity is 15.0% (metallic element weight scaled value).
Comparative example 1
(particle diameter is less than 120 orders for 100 gram γ-alundum (Al powder, specific area: be not less than 250 meters squared per gram) be soaked in decide in the silver nitrate aqueous solution of concentration, stirred 1 hour, after 90 ℃ of dryings, in air, interimly be warming up to 700 ℃ from 100 ℃, kept 3 hours, reduce to room temperature, it is standby to get the 0.5-1.0mm particle after the pulverizing, is comparative catalyst A.The silver components load capacity of manufactured goods catalyst is 5.0%.
Embodiment 2
Enforcement catalyst A and comparative catalyst A that 1.5 grams are made by above method for making are positioned over respectively in the tubular reactor, feed 4 liters/per minute of simulation Rarefied combustion tail gas as shown in table 1, and corresponding air speed (GHSV) is 50,000/ hours.The temperature that enters the simulated exhaust gas of reactor begins to warm to 600 ℃ from 200 ℃, observe catalytic reaction when reaching stable state nitrogen oxide by the situation of third rare reduction.
Utilize chemiluminescence formula nitrogen oxide (nitric oxide, nitrogen dioxide and total nitrogen oxide) analysis-e/or determining by the nitrous oxides concentration in the simulated exhaust gas behind the catalyst (nitric oxide and nitrogen dioxide sum).Experimental result sees Table 2.
Table 1
Constituent concentration
Nitric oxide 700ppm
Carbon monoxide 90ppm
Sulfur dioxide 80ppm
Oxygen 10% volume ratio
Third rare 1500ppm
Nitrogen balance
Water 10% volume ratio
Air speed (GHSV) 50,000/ hours
Table 2
The simulated exhaust gas temperature (℃) 250 300 350 400 450 500 550 600
Comparative catalyst A
Transformation efficiency of the oxides of nitrogen (%) 0.0 11.5 14.0 33.5 67.5 82.0 57.5 21.5
Implement catalyst A
Transformation efficiency of the oxides of nitrogen (%) 9.5 1 8.0 45.5 77.0 85.5 82.5 55.0 23.0
As can be seen from Table 2, use aforesaid enforcement catalyst A can in wider temperature range, remove nitrogen oxide well, amazingly especially be, in low temperature 250-450 ℃ scope, average transformation efficiency of the oxides of nitrogen is 47.1%, exceeds nearly one times than the average transformation efficiency of the oxides of nitrogen 25.3% of comparative catalyst A in the same temperature range.Generally the temperature than the stoichiometric proportion combustion tail gas is low to consider the temperature of Rarefied combustion tail gas, and this is a particularly advantageous factor.
As mentioned above, use catalyst provided by the invention, can the nitrogen oxide in the Rarefied combustion tail gas effectively be purified.Catalyst provided by the invention can be widely used in Diesel engine, the motor vehicles such as lean-burn gasoline engine and natural gas engine or the fixing tail gas clean-up of lean burn device.
Claims (7)
1. one kind is used for the catalyst of purification of combustion tail gas, it is characterized in that, under the environment of oxygen surplus, can optionally utilize simultaneously organic matter and carbon monoxide reduction to remove in the tail gas nitrogen oxide and oxidation and remove imperfect combustion organic matter and carbon monoxide, this catalyst is made of silver components, noble metal component and other metal components that load is held on the porous inorganic thing carrier.
2. the described catalyst of claim 1 as described above is characterized in that, aforementioned noble metal component can be at least a among the following noble metal group, and aforementioned other metal components can be at least a in following other metal groups.
Noble metal group: gold, platinum, palladium, rhodium, iridium, ruthenium
Other metal groups: iron, copper, titanium, zirconium, barium, tin, tungsten, zinc, molybdenum, cerium, caesium, lanthanum, calcium
3. the described catalyst of claim 1 as described above, it is characterized in that, aforementioned silver components, noble metal component and other metal components can be simultaneously or are loaded on the same porous inorganic thing carrier with any sequencing and to constitute catalyst, also can load on respectively on the different porous inorganic thing carriers to constitute catalyst by mixing.
4. the described catalyst of claim 1 as described above, it is characterized in that, the load capacity of the silver components on the aforementioned porous inorganic thing carrier is 0.1-10% (a metallic element weight scaled value), the load capacity of noble metal component is 0.01-1.5% (a metallic element weight scaled value), and other metal component load capacity are 1.0-25% (metallic element weight scaled value).
5. the described catalyst of claim 1 as described above is characterized in that, aforementioned silver components can be the form of the oxide of silver and silver and any inorganic salts and do not change its effect.Aforementioned noble metal component can be the form of the oxide of this noble metal and this noble metal and any inorganic salts and do not change its effect.Aforementioned other metal components can be the forms of the oxide of this metal and this metal and any inorganic salts and do not change its effect.
6. the described catalyst of claim 1 as described above, it is characterized in that aforementioned porous inorganic thing carrier can be alundum (Al, silica, zeolite, sepiolite, titanium dioxide, zirconium dioxide, zinc oxide, magnesia, tin ash one or more hopcalites or its composite oxides, porous carbon material wherein.Aforesaid porous inorganic thing carrier should have 10 meters squared per gram or bigger specific area.Aforesaid porous inorganic oxide carrier can be Powdered also can be the coccoid of moulding.
7. the described catalyst of claim 1 as described above is characterized in that, according to different requirements catalyst is coated in the form of coating on the wall surface of circulation passage of pottery or metal honeycomb, or catalyst is made spherical or tabular.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100355488C (en) * | 2003-05-07 | 2007-12-19 | 韩国高化环保技术有限公司 | Catalytic process for nitrogen oxides reduction by multi-injection and use thereof |
| CN101068616B (en) * | 2004-10-04 | 2011-07-13 | 巴斯福股份公司 | Zeolite catalyst for the simultaneous removal of carbon monoxide and hydrocarbons from oxygen-rich exhaust gases and processes for the manufacture thereof |
| CN101632926B (en) * | 2009-04-09 | 2012-05-16 | 大连华昌隆减排技术有限公司 | Exhaust gas catalysts and exhaust-gas catalytic converter |
| CN102787888A (en) * | 2011-05-19 | 2012-11-21 | 通用汽车环球科技运作有限责任公司 | Oxidation catalysts for engines producing low temperature exhaust streams |
| CN101537351B (en) * | 2008-03-21 | 2013-03-27 | 北京合创同盛科技有限公司 | Catalyst for catalytic combustion |
| CN103433028A (en) * | 2013-08-16 | 2013-12-11 | 南京工业大学 | Three-way NOx, CO and HC removing catalyst used in marine engine, and preparation method thereof |
| CN103949249A (en) * | 2014-04-11 | 2014-07-30 | 浙江大学 | Catalyst used for gas-fired boiler carbon monoxide selective reduction of nitrogen oxides, and preparation method thereof |
| CN104307561A (en) * | 2014-07-15 | 2015-01-28 | 台州欧信环保净化器有限公司 | Oxidative catalyst used for purifying diesel vehicle exhaust, and manufacturing method thereof |
| CN105032410A (en) * | 2015-06-03 | 2015-11-11 | 中国科学院生态环境研究中心 | Ag/Al2O3 catalyst as well as preparation method and application thereof |
| CN106977959A (en) * | 2017-03-28 | 2017-07-25 | 常州大学 | A kind of preparation method of cleaning of off-gas type modified pitch |
| CN110013829A (en) * | 2019-01-21 | 2019-07-16 | 北京工业大学 | Order mesoporous CMK-3 load Ba/Rh or K/Mo adsorbent of a kind of cryogenic absorption NOx and preparation method thereof |
| CN110821610A (en) * | 2019-12-11 | 2020-02-21 | 湘潭大学 | Gasoline car sleeve type molecular sieve hydrocarbon adsorption type catalytic converter |
| WO2020082198A1 (en) * | 2018-10-22 | 2020-04-30 | Pujing Chemical Industry Co., Ltd | Catalyst for treatment of tail gas and preparation thereof |
| CN114669295A (en) * | 2022-03-25 | 2022-06-28 | 无锡威孚环保催化剂有限公司 | Catalyst for reducing exhaust emission of gas engine and application thereof |
| CN114762828A (en) * | 2021-01-13 | 2022-07-19 | 长城汽车股份有限公司 | Anti-sulfur poisoning catalyst, LNT device, tail gas treatment system and vehicle |
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2002
- 2002-12-20 CN CN 02157917 patent/CN1209195C/en not_active Expired - Fee Related
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| CN100355488C (en) * | 2003-05-07 | 2007-12-19 | 韩国高化环保技术有限公司 | Catalytic process for nitrogen oxides reduction by multi-injection and use thereof |
| CN101068616B (en) * | 2004-10-04 | 2011-07-13 | 巴斯福股份公司 | Zeolite catalyst for the simultaneous removal of carbon monoxide and hydrocarbons from oxygen-rich exhaust gases and processes for the manufacture thereof |
| CN101537351B (en) * | 2008-03-21 | 2013-03-27 | 北京合创同盛科技有限公司 | Catalyst for catalytic combustion |
| CN101632926B (en) * | 2009-04-09 | 2012-05-16 | 大连华昌隆减排技术有限公司 | Exhaust gas catalysts and exhaust-gas catalytic converter |
| CN102787888A (en) * | 2011-05-19 | 2012-11-21 | 通用汽车环球科技运作有限责任公司 | Oxidation catalysts for engines producing low temperature exhaust streams |
| CN102787888B (en) * | 2011-05-19 | 2015-05-27 | 通用汽车环球科技运作有限责任公司 | Oxidation catalysts for engines producing low temperature exhaust streams |
| CN103433028A (en) * | 2013-08-16 | 2013-12-11 | 南京工业大学 | Three-way NOx, CO and HC removing catalyst used in marine engine, and preparation method thereof |
| CN103949249A (en) * | 2014-04-11 | 2014-07-30 | 浙江大学 | Catalyst used for gas-fired boiler carbon monoxide selective reduction of nitrogen oxides, and preparation method thereof |
| CN104307561A (en) * | 2014-07-15 | 2015-01-28 | 台州欧信环保净化器有限公司 | Oxidative catalyst used for purifying diesel vehicle exhaust, and manufacturing method thereof |
| CN105032410B (en) * | 2015-06-03 | 2017-08-11 | 中国科学院生态环境研究中心 | A kind of Ag/Al2O3Catalyst, preparation method and its usage |
| CN105032410A (en) * | 2015-06-03 | 2015-11-11 | 中国科学院生态环境研究中心 | Ag/Al2O3 catalyst as well as preparation method and application thereof |
| CN106977959A (en) * | 2017-03-28 | 2017-07-25 | 常州大学 | A kind of preparation method of cleaning of off-gas type modified pitch |
| WO2020082198A1 (en) * | 2018-10-22 | 2020-04-30 | Pujing Chemical Industry Co., Ltd | Catalyst for treatment of tail gas and preparation thereof |
| CN110013829A (en) * | 2019-01-21 | 2019-07-16 | 北京工业大学 | Order mesoporous CMK-3 load Ba/Rh or K/Mo adsorbent of a kind of cryogenic absorption NOx and preparation method thereof |
| CN110013829B (en) * | 2019-01-21 | 2022-03-15 | 北京工业大学 | Low-temperature NOx adsorption ordered mesoporous CMK-3 loaded Ba/Rh or K/Mo adsorbent and preparation method thereof |
| CN110821610A (en) * | 2019-12-11 | 2020-02-21 | 湘潭大学 | Gasoline car sleeve type molecular sieve hydrocarbon adsorption type catalytic converter |
| CN110821610B (en) * | 2019-12-11 | 2021-11-12 | 湘潭大学 | Gasoline car sleeve type molecular sieve hydrocarbon adsorption type catalytic converter |
| CN114762828A (en) * | 2021-01-13 | 2022-07-19 | 长城汽车股份有限公司 | Anti-sulfur poisoning catalyst, LNT device, tail gas treatment system and vehicle |
| CN114762828B (en) * | 2021-01-13 | 2024-04-05 | 长城汽车股份有限公司 | Sulfur poisoning resistant catalyst, LNT device, tail gas treatment system and vehicle |
| CN114669295A (en) * | 2022-03-25 | 2022-06-28 | 无锡威孚环保催化剂有限公司 | Catalyst for reducing exhaust emission of gas engine and application thereof |
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Assignee: Changzhou hi tech Environmental Protection Technology Co.,Ltd. Assignor: Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences Contract record no.: 2010320000436 Denomination of invention: Oxygen-enriched tail gas nitrogen oxide purifying catalyst Granted publication date: 20050706 License type: Exclusive License Open date: 20040707 Record date: 20100504 |
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