CN1454702A - Fuel-lean vehicular engine exhaust gas catalyzing and purifying method - Google Patents
Fuel-lean vehicular engine exhaust gas catalyzing and purifying method Download PDFInfo
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- CN1454702A CN1454702A CN03140511A CN03140511A CN1454702A CN 1454702 A CN1454702 A CN 1454702A CN 03140511 A CN03140511 A CN 03140511A CN 03140511 A CN03140511 A CN 03140511A CN 1454702 A CN1454702 A CN 1454702A
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- 238000000034 method Methods 0.000 title claims abstract description 26
- 239000003054 catalyst Substances 0.000 claims abstract description 76
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims abstract description 56
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims abstract description 38
- 229910000510 noble metal Inorganic materials 0.000 claims abstract description 19
- 238000000746 purification Methods 0.000 claims abstract description 13
- 239000007921 spray Substances 0.000 claims abstract description 4
- 229910000314 transition metal oxide Inorganic materials 0.000 claims abstract description 4
- 239000000203 mixture Substances 0.000 claims abstract description 3
- 239000004215 Carbon black (E152) Substances 0.000 claims description 28
- 229930195733 hydrocarbon Natural products 0.000 claims description 28
- 150000002430 hydrocarbons Chemical class 0.000 claims description 27
- 230000003197 catalytic effect Effects 0.000 claims description 23
- 230000003647 oxidation Effects 0.000 claims description 15
- 238000007254 oxidation reaction Methods 0.000 claims description 15
- 230000001603 reducing effect Effects 0.000 claims description 15
- 229910052697 platinum Inorganic materials 0.000 claims description 13
- 229910044991 metal oxide Inorganic materials 0.000 claims description 11
- 150000004706 metal oxides Chemical class 0.000 claims description 11
- 229910052709 silver Inorganic materials 0.000 claims description 9
- 229910052718 tin Inorganic materials 0.000 claims description 9
- 230000000694 effects Effects 0.000 claims description 8
- 229910052738 indium Inorganic materials 0.000 claims description 7
- 229910052763 palladium Inorganic materials 0.000 claims description 7
- 239000003595 mist Substances 0.000 claims description 6
- 229910052733 gallium Inorganic materials 0.000 claims description 5
- 230000010718 Oxidation Activity Effects 0.000 claims description 3
- 238000010531 catalytic reduction reaction Methods 0.000 claims description 3
- 239000003426 co-catalyst Substances 0.000 claims description 3
- 229910052746 lanthanum Inorganic materials 0.000 claims description 2
- 229910052727 yttrium Inorganic materials 0.000 claims description 2
- 229910052726 zirconium Inorganic materials 0.000 claims description 2
- 238000006243 chemical reaction Methods 0.000 abstract description 26
- 238000007599 discharging Methods 0.000 abstract description 5
- 230000009467 reduction Effects 0.000 abstract description 2
- MWUXSHHQAYIFBG-UHFFFAOYSA-N Nitric oxide Chemical compound O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 93
- 229910002091 carbon monoxide Inorganic materials 0.000 description 38
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 37
- 229910052760 oxygen Inorganic materials 0.000 description 13
- 239000003638 chemical reducing agent Substances 0.000 description 11
- 238000002156 mixing Methods 0.000 description 7
- 238000002360 preparation method Methods 0.000 description 7
- 238000004088 simulation Methods 0.000 description 7
- IKHGUXGNUITLKF-UHFFFAOYSA-N Acetaldehyde Chemical compound CC=O IKHGUXGNUITLKF-UHFFFAOYSA-N 0.000 description 6
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 6
- 239000001301 oxygen Substances 0.000 description 6
- 230000002829 reductive effect Effects 0.000 description 5
- 238000006555 catalytic reaction Methods 0.000 description 4
- 239000000446 fuel Substances 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 239000005431 greenhouse gas Substances 0.000 description 3
- 238000007654 immersion Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- WSFSSNUMVMOOMR-NJFSPNSNSA-N methanone Chemical compound O=[14CH2] WSFSSNUMVMOOMR-NJFSPNSNSA-N 0.000 description 3
- 150000002894 organic compounds Chemical class 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 238000011160 research Methods 0.000 description 3
- 230000011218 segmentation Effects 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- 229910021536 Zeolite Inorganic materials 0.000 description 2
- 150000001336 alkenes Chemical class 0.000 description 2
- 238000001354 calcination Methods 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 239000000919 ceramic Substances 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 238000002485 combustion reaction Methods 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 239000000470 constituent Substances 0.000 description 2
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- -1 low-carbon alkanes Chemical class 0.000 description 2
- 229910021645 metal ion Inorganic materials 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 238000006722 reduction reaction Methods 0.000 description 2
- 238000003980 solgel method Methods 0.000 description 2
- 239000010457 zeolite Substances 0.000 description 2
- 241000252206 Cypriniformes Species 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 150000001335 aliphatic alkanes Chemical class 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000000295 complement effect Effects 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000002283 diesel fuel Substances 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 239000003344 environmental pollutant Substances 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000008246 gaseous mixture Substances 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- 231100000719 pollutant Toxicity 0.000 description 1
- 239000012495 reaction gas Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Images
Classifications
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/12—Improving ICE efficiencies
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Abstract
The invention is catalyst purifying method for tails discharged by fuel-lean car engine. The invention provides a method which applies to fuel-lean car engine, reduces NOx in tails efficiently in wide temperature range, and oxidizes HC and CO. The method includes following steps: sprays carbinol or alcohol into discharging pipe, and makes it blend with the engine tails; the mixed gas is transmitted to front grade catalyzing reaction bed which is loaded with transition metal oxide catalyst and the back grade catalyzing reaction bed which is loaded with laden noble metal catalyst, realizes the purification of NOx, HC and CO with high efficiency, and finally discharges normal gas. The invention can spread the range of NOx reduction active temperature.
Description
Technical field
Poor combustion is meant the burning of carrying out under the air excess condition, the present invention relates to the fuel-lean type vehicular engine exhaust catalytic purification method of two kinds of catalyst of a kind of segmentation combination as catalyst system, belongs to the automobile exhaust catalysis and purification technical field.
Background technology
Current, the mainstream technology of automobile exhaust gas purifying is that three-effect catalysis transforms, and this purification techniques requires engine to work under the stoichiometric ratio condition, only is applicable to gasoline engine, and to a certain extent, is to be cost with the economy of sacrificing fuel.Along with to energy-conservation and reduce greenhouse gases CO
2The pay attention to day by day of discharging, the fuel-lean type vehicular engine comprises that the market prospects of diesel engine and fuel-lean type gasoline engine are more and more wide.With gasoline or diesel oil is that the vehicular engine of fuel adopts poor combustion mode can improve fuel availability, improves fuel economy, reduces CO
2Discharging Deng pollutant.But the fuel-lean type engine exhaust is rich in oxygen, and triple effect catalytic converter business-like, that be complementary with the stoichiometric ratio working method can not purify NOx wherein effectively.
Round the catalytic purification of fuel-lean type vehicular engine exhaust, carried out 10 years of researches both at home and abroad, its emphasis is how NOx to be reduced to N
2A large amount of studies show that, in certain temperature range, the NOx of hydrocarbons such as low-carbon alkanes, alkene and alcohols in can the SCR oxygen-enriched atmosphere is a kind of fuel-lean type vehicular engine low-emission technology with practical prospect.Three pieces of authoritative survey articles: 1) M.D.Amiridis, T.J.Zhang, R.J.Farrauto.Appl.Catal.B10,203 (1996); 2) A.Fritz, V.Pitchon.Appl.Catal.B13,1 (1997); 3) R.Burch, J.P.Breen, EC.Meunier.Appl.Catal.B39,283 (2002) summarize research in this respect.Generally speaking, up to the present, the catalyst of studying can be divided into the zeolite and the metal oxide three major types of carried noble metal, metal ion exchanged.These catalyst all have certain NO reducing activity, still, only rely on single main active constituent catalyst, and not during additional reducing agent, NO reducing activity temperature range is narrow, and is incompatible with the characteristic of vehicular engine delivery temperature wider range.In addition, for loaded noble metal catalyst, also exist the NO of poor selectivity, significant quantity to be reduced to greenhouse gases N
2O; For the zeolite catalyst of metal ion exchanged, also exist hydrothermal stability poor; For metal oxide catalyst, also exist active temperature to be higher than the problems such as main delivery temperature scope of fuel-lean type vehicular engine.
In order to overcome the deficiency of single main active constituent catalyst, utilize in combination in recent years and done many researchs aspect the catalyst, the result shows, with C
3H
6Or C
3H
8Be reducing agent, segmentation combination Rh/Al
2O
3And Pt/Al
2O
3(H.Hamada.CatalysisSurveys from Japan, 1,53 (1997)), at Ga
2O
3-Al
2O
3In mixes in the catalyst
2O
3(M.Haneda, Y.Kintaichiand H.Hamada.Catalysis Letters, 55,47 (1998)) etc. all have certain collaborative reductive NO effect, or widen the active temperature scope, or improve the NO conversion ratio, but action effect is not remarkable, requires also far apart from practicability.In addition, still there is greenhouse gases N for the catalyst that with the noble metal is NOx reducing activity component
2The generation problem of O.
Summary of the invention
The object of the present invention is to provide a kind of and fuel-lean type vehicular engine suitable, in wider temperature range, can efficiently reduce NOx in the exhaust, and can be CO HC and CO efficient oxidation
2And H
2The method of O with practicability.
The invention discloses two kinds of catalyst of a kind of segmentation combination as catalyst system, work in coordination with and utilize the contained hydrocarbon of engine exhaust and add methyl alcohol or ethanol, can make nitrogen oxide (NOx), hydrocarbon (HC) and carbon monoxide (CO) in the exhaust of fuel-lean type vehicular engine be converted into nitrogen (N as the fuel-lean type vehicular engine exhaust catalytic purification method of NO reducing agent
2), water (H
2O) and carbon dioxide (CO
2).
Technical scheme of the present invention is a kind of fuel-lean type vehicular engine exhaust catalytic purification method, it is characterized in that this method comprises the steps:
(1) at first in the exhaust pipe of engine, sprays into methyl alcohol or ethanol, make it to mix with engine exhaust is full and uniform;
(2) the prime catalytic bed that allows above-mentioned mist enter load type catalyst of transition metal oxide is utilized exhaust institute hydrocarbon-containiproducts and the collaborative reducing NOx effect that adds methyl alcohol or ethanol, reducing NOx; Meanwhile, the contained hydrocarbon of part exhaust and add methyl alcohol or ethanol is oxidized to CO
2, or CO, formaldehyde, acetaldehyde and other organic compounds.
(3) mist that allows the prime catalytic bed discharge enters the back level catalytic bed of load type noble metal catalyst.Utilize the catalytic oxidation ability of noble metal catalyst, catalytic oxidation is residual hydrocarbon, methyl alcohol or the ethanol of the discharge of order reaction bed in the past, and CO, formaldehyde, acetaldehyde and other organic compounds are CO
2And H
2O; Meanwhile, utilize the exhaust institute hydrocarbon-containiproducts, methyl alcohol, the further catalytic reduction of NOx of ethanol that in the prime catalytic bed, do not act on, finally discharge gas up to standard.
The main active component of supported transitional metal oxide catalyst of the present invention is the oxide of Ag, Sn, Co, In or Ga, and catalyst is with Al
2O
3Be coated carrier.
The main active component of loaded noble metal catalyst of the present invention is Pt or Pd, and catalyst is with Al
2O
3Be coated carrier.
The oxide of La, Y or Zr of can mixing in the coated carrier of supported transitional metal oxide catalyst of the present invention and loaded noble metal catalyst is made co-catalyst.
Experiment shows, Ag/Al
2O
3With Pt/Al
2O
3Be combined as the catalyst combination of combination property optimum.
Catalyst system of the present invention is formed by supported transitional metal oxide catalyst and loaded noble metal catalyst tandem compound, and reaction gas through supported transitional metal oxide catalyst, passes through loaded noble metal catalyst earlier again.The main NOx that takes place is reduced to N on supported transitional metal oxide catalyst
2Reaction; Main generation organic compound and CO are oxidized to CO on loaded noble metal catalyst
2And H
2The reaction of O.
The present invention compared with prior art has the following advantages and beneficial effect: 1) active temperature of methyl alcohol and ethanol reducing NOx is low, and the active temperature height of contained alkene of engine exhaust and alkane reducing NOx.The collaborative reducing NOx effect of utilizing the different reducing agents of two classes can improve the NOx conversion ratio, widens the active temperature scope, also can reduce methyl alcohol or consumption of ethanol; 2) at supported transitional metal oxide catalyst surface NO x reducing activity temperature height, and low in loaded noble metal catalyst surface NO x reducing activity temperature, be used in combination two class catalyst, can improve the NOx conversion ratio, widen the active temperature scope; 3) loaded noble metal catalyst is very high for the oxidation activity of each hydrocarbon, oxygen-bearing hydrocarbon and CO, just they can be oxidized to CO at low temperatures
2And H
2O.Therefore, series load type noble metal catalyst after supported transitional metal oxide catalyst, but the efficient oxidation not hydrocarbon of complete oxidation, oxygen-bearing hydrocarbon and CO on front stage catalyst, and the hydrocarbon that in the prime catalytic reaction, produces, oxygen-bearing hydrocarbon and CO, guarantee hydrocarbon, oxygen-bearing hydrocarbon and CO qualified discharge.
Description of drawings
Fig. 1 is the structural principle schematic diagram of fuel-lean type vehicular engine exhaust catalytic purification method equipment therefor.
The specific embodiment
The method of the invention combination has utilized vehicular engine exhaust institute hydrocarbon-containiproducts and has added methyl alcohol or ethanol at Ag/Al
2O
3, Co/Al
2O
3, Ga/Al
2O
3, In/Al
2O
3Or Sn/Al
2O
3Work in coordination with the effect of reducing NOx on the catalyst, significantly widened the active temperature scope of reducing NOx.Simultaneously, consider that the vehicular engine exhaust contains some at Ag/Al
2O
3, Co/Al
2O
3, Ga/Al
2O
3, In/Al
2O
3Or Sn/Al
2O
3Hydrocarbon and CO that can not complete oxidation on the catalyst, and at Ag/Al
2O
3, Co/Al
2O
3, Ga/Al
2O
3, In/Al
2O
3Or Sn/Al
2O
3In the catalytic reduction of NOx process, can generate CO and formaldehyde, acetaldehyde or other harmful organic products on the catalyst, Pt/Al connects thereafter
2O
3Or Pd/Al
2O
3Catalyst.Utilize Pt/Al
2O
3Or Pd/Al
2O
3The low-temperature oxidation activity of catalyst, can be under lower temperature each hydrocarbon of oxidation and CO be CO
2And H
2O prevents hydrocarbon and the CO discharging that exceeds standard.In addition, under lower temperature, Pt/Al
2O
3Or Pd/Al
2O
3Catalyst also has certain reducing NOx activity.
As shown in Figure 1, after the gas of discharging from fuel-lean type vehicular engine 1 enters the exhaust pipe of engine 2, at first evenly mix with methyl alcohol or the ethanol that nozzle 3 sprays into, flow through the prime catalytic bed 4 of load type catalyst of transition metal oxide then earlier, in this reaction bed, the main NOx reduction reaction that takes place, NOx is by methyl alcohol, ethanol and the hydrocarbon-containiproducts reduction of engine exhaust institute.Then, mist enters the back level catalytic bed 5 of load type noble metal catalyst, and in this reaction bed, on the one hand, NOx is further reduced by hydrocarbon; On the other hand, HC and CO are oxidized to CO
2And H
2O.Experimental study shows, with NO, C
3H
6, O
2, CO, SO
2, H
2O, He or N
2The exhaust of gaseous mixture simulation fuel-lean type vehicular engine, to load on Al
2O
3On Ag, Co, Ga, In or Sn oxide with load on Al
2O
3On Pt or Pd tandem compound constitute catalyst, add methyl alcohol or ethanol and engine exhaust institute hydrocarbon-containiproducts and work in coordination with and make reducing agent.When air speed is 30,000～55,000h
-1, the mol ratio of methyl alcohol or ethanol/NOx is 1～4 o'clock, in about 230～550 ℃ temperature range, the NOx conversion ratio can reach more than 60%; More than 250 ℃, hydrocarbon just can be converted into CO fully about
2And H
2O.
Ag/Al of the present invention
2O
3, Co/Al
2O
3, Ga/Al
2O
3, In/Al
2O
3, Sn/Al
2O
3And Pt/Al
2O
3, Pd/Al
2O
3Catalyst can adopt step sol-gel process preparation, i.e. preparation earlier contains the Al of active component A g, Co, Ga, In, Sn or Pt, Pd
2O
3Colloidal sol is coated on the ceramic honeycomb carrier, drying and calcination process then again.Also can adopt immersion process for preparing, promptly earlier with Al
2O
3Be coated on the ceramic honeycomb carrier, and then dipping active component A g, Co, In, Sn or Pt, Pd etc., last, carry out drying and calcination process.At Al
2O
3The oxide of La, Ya or Zr of can mixing in the coating is made co-catalyst.When adopting that a step, sol-gel process prepared, the load capacity of Ag, Co, Ga, In, Sn and Pt, Pd is respectively about 5%, 5%, 27%, 5%, 5% and 2%, 2%; When adopting immersion process for preparing, the load capacity of Ag, Co, In, Sn and Pt, Pd is respectively about 2%, 2%, 2%, 2% and 1%, 1%.
The exhaust of simulation fuel-lean type vehicular engine is by 1000ppm NO, 1000ppm C
3H
6, 3000ppm CO, 8%O
2, 1%H
2O, 100ppmSO
2And N
2Form, additional reducing agent is CH
3OH, its concentration is 2200ppm.Combination catalyst is by Ag/Al
2O
3And Pt/Al
2O
3Be composed in series, two kinds of catalyst all adopt the preparation of sol-gel mixing method, and the weight percentage of Ag and Pt is respectively 5% and 2%.When air speed is 33,000h
-1, when reaction temperature was 230～500 ℃, the NOx conversion ratio was higher than 60%, and about more than 250 ℃, but HC and CO complete oxidation are CO
2And H
2O.
The exhaust of simulation fuel-lean type vehicular engine is by 1000ppm NO, 1000ppm C
3H
6, 8%O
2, 1%H
2O, 100ppmSO
2And N
2Form, additional reducing agent is C
2H
5OH, its concentration is 2300ppm.Combination catalyst is by Ag/Al
2O
3And Pt/Al
2O
3Be composed in series, two kinds of catalyst all adopt the preparation of sol-gel mixing method, and the weight percentage of Ag and Pt is respectively 5% and 2%.When air speed is 33,000h
-1, when reaction temperature was 300～550 ℃, the NOx conversion ratio was higher than 60%, about more than 300 ℃, but the HC complete oxidation.
The exhaust of simulation fuel-lean type vehicular engine is by 1000ppm NO, 600ppm C
3H
6, 8%O
2, 5000ppm CO, 1%H
2O, 100ppmSO
2And N
2Form, additional reducing agent is CH
3OH, its concentration is 3500ppm.Combination catalyst is by Sn/Al
2O
3And Pt/Al
2O
3Be composed in series, two kinds of catalyst all adopt the preparation of sol-gel mixing method, and the weight percentage of Sn and Pt is respectively 5% and 2%.When air speed is 33,000h
-1, when reaction temperature was 200～550 ℃, the NOx conversion ratio was higher than 60%, and about more than 250 ℃, but HC and CO complete oxidation are CO
2And H
2O.
The exhaust of simulation fuel-lean type vehicular engine is by 1000ppm NO, 1000ppm C
3H
6, 8%O
2, 1%H
2O, 100ppmSO
2And N
2Form, additional reducing agent is C
2H
5OH, its concentration is 3300ppm.Combination catalyst is by Sn/Al
2O
3And Pt/Al
2O
3Be composed in series, two kinds of catalyst all adopt the preparation of sol-gel mixing method, and the weight percentage of Sn and Pt is respectively 5% and 2%.When air speed is 33,000h
-1, when reaction temperature was 250～550 ℃, the NOx conversion ratio was higher than 60%, about more than 300 ℃, but the HC complete oxidation.At prime Sn/Al
2O
3A large amount of CO that reaction generates on the catalyst, about more than 250 ℃, can be by back level Pt/Al
2O
3The catalyst complete oxidation.
The exhaust of simulation fuel-lean type vehicular engine is by 1000ppm NO, 500ppm C
3H
6, 8%O
2, 1%H
2O, 100ppmSO
2And N
2Form, additional reducing agent is CH
3OH, its concentration is 3500ppm.Combination catalyst is by Ag/Al
2O
3And Pt/Al
2O
3Be composed in series, two kinds of catalyst all adopt the preparation of sol-gel mixing method, and the weight percentage of Ag and Pt is respectively 5% and 2%.When air speed is 47,000h
-1, when reaction temperature was 250～500 ℃, the NOx conversion ratio was higher than 60%, and more than 250 ℃, the HC complete oxidation is CO about
2And H
2O.When reaction temperature during greater than 250 ℃, combination catalyst agent outlet does not detect CO.
Embodiment 6
The exhaust of simulation fuel-lean type vehicular engine is by 1000ppm NO, 1000ppm C
3H
6, 8%O
2, 1%H
2O, 100ppmSO
2And N
2Form, additional reducing agent is C
2H
5OH, its concentration is 2200ppm.Combination catalyst is by Ag/Al
2O
3And Pt/Al
2O
3Be composed in series, two kinds of catalyst all adopt immersion process for preparing, and the weight percentage of Ag and Pt is respectively 2% and 1%.When air speed is 33,000h
-1, when reaction temperature was 250～500 ℃, the NOx conversion ratio was higher than 60%, and more than 250 ℃, the HC complete oxidation is CO about
2And H
2O.When reaction temperature during greater than 250 ℃, combination catalyst agent outlet does not detect CO.
Claims (4)
1. a fuel-lean type vehicular engine exhaust catalytic purification method is characterized in that this method comprises the steps:
(1) at first in the exhaust pipe of engine, sprays into methyl alcohol or ethanol, make it to mix with engine exhaust is full and uniform;
(2) allow above-mentioned mist enter the prime catalytic bed of load type catalyst of transition metal oxide, utilize exhaust institute hydrocarbon-containiproducts and the collaborative reducing NOx effect that adds methyl alcohol or ethanol, reducing NOx, and make the contained hydrocarbon of part exhaust and add methyl alcohol or ethanol is oxidized;
(3) mist that allows the prime catalytic bed discharge enters the back level catalytic bed of load type noble metal catalyst, utilizes the oxidation activity of noble metal catalyst, hydrocarbon, methyl alcohol, ethanol and CO that the described mist of efficient oxidation contains; And utilize exhaust institute hydrocarbon-containiproducts, methyl alcohol, the further catalytic reduction of NOx of ethanol that in the prime catalytic bed, does not act on, finally discharge gas up to standard.
2. fuel-lean type vehicular engine exhaust catalytic purification method according to claim 1, it is characterized in that: the main active component of described supported transitional metal oxide catalyst is the oxide of Ag, Sn, Co, In or Ga, and catalyst is with Al
2O
3Be coated carrier.
3. fuel-lean type vehicular engine exhaust catalytic purification method according to claim 1 and 2, it is characterized in that: the main active component of described loaded noble metal catalyst is Pt or Pd, and catalyst is with Al
2O
3Be coated carrier.
4. fuel-lean type vehicular engine exhaust catalytic purification method according to claim 3, it is characterized in that: the oxide of can mix in the coated carrier of described supported transitional metal oxide catalyst and loaded noble metal catalyst La, Y or Zr is made co-catalyst.
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|---|---|---|---|
| CNB031405118A CN1208118C (en) | 2003-05-27 | 2003-05-27 | Fuel-lean vehicular engine exhaust gas catalyzing and purifying method |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB031405118A CN1208118C (en) | 2003-05-27 | 2003-05-27 | Fuel-lean vehicular engine exhaust gas catalyzing and purifying method |
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| Publication Number | Publication Date |
|---|---|
| CN1454702A true CN1454702A (en) | 2003-11-12 |
| CN1208118C CN1208118C (en) | 2005-06-29 |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100371072C (en) * | 2005-09-30 | 2008-02-27 | 清华大学 | Preparation process of selective reduction catalyst for lean-burn gasoline motor car exhausted gas nitrogen oxide |
| CN101542085B (en) * | 2007-03-19 | 2011-08-17 | 丰田自动车株式会社 | Exhaust cleaner for internal combustion engine |
| CN103008002A (en) * | 2012-12-11 | 2013-04-03 | 清华大学 | Preparation method and application of Fe and Cu composite molecular sieve catalyst |
| CN103945918A (en) * | 2011-10-06 | 2014-07-23 | 马克卡车公司 | Diesel oxidation catalyst and method of treating engine exhaust gas |
| CN106984304A (en) * | 2017-04-28 | 2017-07-28 | 华南理工大学 | A kind of Ru Ag bimetal composite denitrating catalysts and its preparation method and application |
-
2003
- 2003-05-27 CN CNB031405118A patent/CN1208118C/en not_active Expired - Fee Related
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100371072C (en) * | 2005-09-30 | 2008-02-27 | 清华大学 | Preparation process of selective reduction catalyst for lean-burn gasoline motor car exhausted gas nitrogen oxide |
| CN101542085B (en) * | 2007-03-19 | 2011-08-17 | 丰田自动车株式会社 | Exhaust cleaner for internal combustion engine |
| US8215101B2 (en) | 2007-03-19 | 2012-07-10 | Toyota Jidosha Kabushiki Kaisha | Exhaust purification device of an internal combustion engine |
| CN103945918A (en) * | 2011-10-06 | 2014-07-23 | 马克卡车公司 | Diesel oxidation catalyst and method of treating engine exhaust gas |
| CN103008002A (en) * | 2012-12-11 | 2013-04-03 | 清华大学 | Preparation method and application of Fe and Cu composite molecular sieve catalyst |
| CN103008002B (en) * | 2012-12-11 | 2015-02-18 | 清华大学 | Preparation method and application of Fe and Cu composite molecular sieve catalyst |
| CN106984304A (en) * | 2017-04-28 | 2017-07-28 | 华南理工大学 | A kind of Ru Ag bimetal composite denitrating catalysts and its preparation method and application |
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