CN100560204C - Catalyst for purification of nitrogen oxides in the sulfur-bearing oxygen enrichment tail gas - Google Patents
Catalyst for purification of nitrogen oxides in the sulfur-bearing oxygen enrichment tail gas Download PDFInfo
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- CN100560204C CN100560204C CNB2003101218797A CN200310121879A CN100560204C CN 100560204 C CN100560204 C CN 100560204C CN B2003101218797 A CNB2003101218797 A CN B2003101218797A CN 200310121879 A CN200310121879 A CN 200310121879A CN 100560204 C CN100560204 C CN 100560204C
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Abstract
The invention provides a kind of catalyst of nitrogen oxide in the tail gas that is used under the catalytic reduction excess oxygen, in tail gas, contain SO
2Condition under, can optionally reduce simultaneously and remove nitrogen oxide and imperfect combustion organic matter and the carbon monoxide of oxidation removal in the Rarefied combustion tail gas, be suitable for the tail gas source and comprise motor-driven or fixed combustion devices such as Diesel engine, lean-burn gasoline engine and natural gas engine.This catalyst loads on the same porous inorganic thing carrier simultaneously or with any sequencing and constitutes by loading on silver components on the porous inorganic thing carrier, noble metal component, other metal components and carrier improver, also can load on respectively on the different porous inorganic thing carriers to constitute catalyst by mixing.It is characterized in that aforementioned noble metal component can be at least a among the following noble metal group, aforementioned other metal components can be at least a in following other metal groups, and the carrier improver can be at least a in the following carrier improver.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; Carrier improver: aluminium colloidal sol, Ludox.
Description
Technical field
The present invention is used for the nitrogen oxide of purification of exhaust gases of internal combustion engines, particularly under excess oxygen, utilizes limited carbon monoxide and organic matter selective reducing nitrogen oxide, and catalyst contains the SO of higher concentration under lower reaction temperature and in the tail gas
2Condition under, higher nitrogen oxide reducing activity is also arranged.
Technical background
This catalyst is 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 (14.1 ± 0.1), 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 diesel engine actual mixing ratio 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.
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: 02157917.2) of the silver catalyst that the interpolation noble metal improves in the past, this catalyst has good low temperature active, and with third rare be in the scope of 300-550 ℃ of simulated exhaust gas temperature of reducing agent, average transformation efficiency of the oxides of nitrogen is 67.8%, but, in the middle of tail gas, have certain density SO
2In the time of (80ppm), the low temperature removal of nitrogen oxide activity of this catalyst is relatively poor.
Summary of the invention
The present invention is directed to the problems referred to above, the silver catalyst that noble metal improves further improved, provide a kind of be used under the excess oxygen combustion tail gas particularly diesel engine vent gas contain certain density SO
2Condition under the catalyst of catalytic cleaning nitrogen oxide, the silver catalyst that improves with respect to noble metal has good cryogenic nitrogen oxide reducing activity.
The effect of invention
The present invention is fully taking into account on the basis of previous studies, has carried out the result of a large amount of thoroughgoing and painstaking researchs.The catalyst that is provided is oxygen content (for example 10% volume) oxygen content when burning far above stoichiometric proportion in tail gas, the steam of 10% volume and 80ppm SO
2Still nitrogen oxide had very high reducing activity under the condition, particularly catalyst (the application number: 02157917.2) be greatly improved before improving than the activity under the low exhaust gas temperature.
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), 1.0-25% (metallic element weight scaled value) and 0.5-15% (alundum (Al or silica scaled value) carrier improver 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 conversion ratio of activity of such catalysts nitrogen oxide can be very low, and silver components can reduce the pyrolytic conversion rate of nitrogen oxide during greater than 10% (metallic element weight scaled value).The silver components of indication 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, zeolite, sepiolite, titanium 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 oxides 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, can be in silver, noble metal and other metal oxides soluble compounds aqueous solution separately with selected porous inorganic thing carrier impregnation, stirred 2-15 hour, 110-150 ℃ 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 oxides 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 integrated 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 Preparation of catalysts
(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) impregnated in certain density silver nitrate, palladium nitrate, ferric nitrate and the silica aqueous solution, stirred 1 hour, after 110 ℃ 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), palladium component load capacity is 0.5% (metallic element weight scaled value), and iron component load capacity is that 15.0% (metallic element weight scaled value), silicon components load capacity are 10% (SiO
2The 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 the silver nitrate of concentration, in the mixed aqueous solution of palladium nitrate, ferric nitrate, stirred 1 hour, after 90 ℃ of dryings, interim ground is warming up to 700 ℃ from 100 ℃ in air, 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% (metallic element weight scaled value), and palladium component load capacity is 0.5% (metallic element weight scaled value), and iron component load capacity is 15.0% (metallic element weight scaled value).
Embodiment 2 excess oxygen propylene selective reduction NO
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.
By the nitrous oxides concentration in the simulated exhaust gas behind the catalyst (nitric oxide and nitrogen dioxide sum), see Table 1, utilize chemiluminescence formula nitrogen oxide (nitric oxide, nitrogen dioxide and total nitrogen oxide) analysis-e/or determining.Experimental result sees Table 2.
Table 1
Table 2
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 42%, is 3.5 times of average transformation efficiency of the oxides of nitrogen 12% 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 be in very wide temperature range, the nitrogen oxide in the higher Rarefied combustion tail gas of sulfur content is effectively 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 (4)
1. one kind is used for the catalyst of purification of combustion tail gas, it is characterized in that, under excess oxygen, contains higher SO in the tail gas
2The environment of concentration under, 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 by the silver components that loads on the porous inorganic thing carrier, noble metal component, other metal components and carrier improver component constitute, the load capacity of silver components is 0.1-10% by metal element wt scaled value, noble metal component is a gold, platinum, palladium, rhodium, iridium, at least a in the ruthenium, load capacity is 0.01-1.5% by metal element wt scaled value, other metal components are iron, copper, titanium, tin, zinc, at least a in the molybdenum, load capacity is 1.0-25% by metal element wt scaled value, the carrier improver is an aluminium colloidal sol, at least a in the Ludox, load capacity is 0.5-15% by alundum (Al or silica scaled value.
2. catalyst as claimed in claim 1, it is characterized in that, described silver components, noble metal component, other metal components and carrier improver load on the same porous inorganic thing carrier simultaneously or with any sequencing and constitute catalyst, or load on respectively on the different porous inorganic thing carriers and constitute catalyst by mixing.
3. catalyst as claimed in claim 1, it is characterized in that, described porous inorganic thing carrier is a kind of in alundum (Al, silica, titanium dioxide, zirconium dioxide, zinc oxide, magnesia, the tin ash or greater than a kind of mixture or its composite oxides, described porous inorganic thing carrier has 10 meters squared per gram or bigger specific area, and described porous inorganic oxide carrier is Powdered or moulding coccoid.
4. catalyst as claimed in claim 1 is characterized in that, 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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| CNB2003101218797A CN100560204C (en) | 2003-12-24 | 2003-12-24 | Catalyst for purification of nitrogen oxides in the sulfur-bearing oxygen enrichment tail gas |
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| CNB2003101218797A CN100560204C (en) | 2003-12-24 | 2003-12-24 | Catalyst for purification of nitrogen oxides in the sulfur-bearing oxygen enrichment tail gas |
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| CN100560204C true CN100560204C (en) | 2009-11-18 |
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| CN102600840A (en) * | 2007-08-09 | 2012-07-25 | 宜安德株式会社 | Catalyst for removing carbon monoxide, hydrocarbons and particulate matters in engine |
| CN102380377B (en) * | 2011-09-07 | 2015-04-22 | 中国第一汽车股份有限公司 | Metal-foam structure unit for POC (particle oxidation catalyst) postprocessor |
| KR101907147B1 (en) * | 2012-03-28 | 2018-10-12 | 현대중공업 주식회사 | Metallic filter for exhaust gas of marine |
| CN102962061A (en) * | 2012-11-09 | 2013-03-13 | 陕西超能石化科技有限公司 | Multifunctional catalyst for removing NOX and SOX in catalytic cracking regeneration flue gas and preparation method of multifunctional catalyst |
| CN103908965B (en) * | 2014-03-14 | 2015-11-18 | 中国石油集团工程设计有限责任公司 | A kind of low-temperature oxidation catalyst for the treatment of sulfur-containing tail gas and preparation method thereof |
| CN105536823B (en) * | 2014-10-28 | 2017-09-29 | 中国石油化工股份有限公司 | A kind of Sulfur-resistant catalytic-combustioncatalyst catalyst and preparation method 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 |
| 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 |
| CN113457660B (en) * | 2021-06-30 | 2023-04-28 | 无锡威孚环保催化剂有限公司 | Catalyst for particle catcher of gasoline car and preparation method thereof |
Citations (4)
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|---|---|---|---|---|
| CN1187780A (en) * | 1995-06-15 | 1998-07-15 | 恩格尔哈德公司 | Diesel engine exhaust gas catalyst and method of use thereof |
| US6093378A (en) * | 1997-05-07 | 2000-07-25 | Engelhard Corporation | Four-way diesel exhaust catalyst and method of use |
| CN1315228A (en) * | 2000-03-01 | 2001-10-03 | dmc2德古萨金属催化剂塞尔德克股份公司 | Catalyst for purifying waste gas from diesel engine and preparing process thereof |
| CN1439455A (en) * | 2002-02-20 | 2003-09-03 | 中国科学院生态环境研究中心 | Rarefied combustion tail gas nitrogen oxide purification catalyst and its purification |
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2003
- 2003-12-24 CN CNB2003101218797A patent/CN100560204C/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1187780A (en) * | 1995-06-15 | 1998-07-15 | 恩格尔哈德公司 | Diesel engine exhaust gas catalyst and method of use thereof |
| US6093378A (en) * | 1997-05-07 | 2000-07-25 | Engelhard Corporation | Four-way diesel exhaust catalyst and method of use |
| CN1315228A (en) * | 2000-03-01 | 2001-10-03 | dmc2德古萨金属催化剂塞尔德克股份公司 | Catalyst for purifying waste gas from diesel engine and preparing process thereof |
| CN1439455A (en) * | 2002-02-20 | 2003-09-03 | 中国科学院生态环境研究中心 | Rarefied combustion tail gas nitrogen oxide purification catalyst and its purification |
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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: Purifying catalyst for nitrogen oxides in sulfur containing oxygen enriching tail gas Granted publication date: 20091118 License type: Exclusive License Open date: 20050629 Record date: 20100504 |
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Granted publication date: 20091118 Termination date: 20211224 |