CN104475120A - Cobalt-vanadium binary oxide type selective catalytic reduction supported catalyst for diesel engine - Google Patents
Cobalt-vanadium binary oxide type selective catalytic reduction supported catalyst for diesel engine Download PDFInfo
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- CN104475120A CN104475120A CN201410724468.5A CN201410724468A CN104475120A CN 104475120 A CN104475120 A CN 104475120A CN 201410724468 A CN201410724468 A CN 201410724468A CN 104475120 A CN104475120 A CN 104475120A
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Abstract
The invention discloses a cobalt-vanadium binary oxide type selective catalytic reduction supported catalyst for a diesel engine. According to the catalyst, the cobalt-vanadium binary oxide is taken as a main active component, WO3 is taken as a cocatalyst, CeO2, ZrO2, gamma-Al2O3 and anatase type TiO2 are combined to form coating auxiliaries, and 400-mesh cordierite honeycomb ceramics are taken as a supported catalyst carrier. The preparation process of the cobalt-vanadium binary oxide type selective catalytic reduction supported catalyst comprises the following steps: determining the usage amounts of the catalyst raw materials, preparing a coating slurry precursor and a coating slurry, and applying the coating slurry. A urea solution or ammonia gas is taken as a reducing agent for the catalyst. According to the cobalt-vanadium binary oxide type selective catalytic reduction supported catalyst for the diesel engine, low-toxicity Co2O3 is adopted to take the place of high-toxicity V2O5, so that the damage caused by the catalyst is reduced and the low-temperature selective catalytic reduction (SCR) reaction catalytic activity of the catalyst is improved. Cerium oxide and zirconium oxide are added to the coating to enhance the oxygen storage capacity of the catalyst; the alumina sol is taken as a coating binder, so that the raw material cost and process difficulty of catalyst production are reduced.
Description
Technical field
The invention belongs to diesel engine vent gas purification techniques, be specifically related to a kind of Catalysts and its preparation method for purifying vehicle exhaust.
Background technology
Along with the swift and violent growth of Global Trends in Motor Vehicle output, vehicle exhaust has become NO_x in Air Environment (NO
xone of) most important source.And NOx not only itself belongs to poisonous, pungent, but also be the presoma of secondary superfine particulate matter and acid rain, serious harm atmospheric environment and health.As the diesel engine of one of motor vehicle major impetus, not only NOx brake specific exhaust emission is higher, and because the single-machine capacity of diesel engine is generally higher than gasoline engine, therefore the NOx discharge of diesel vehicle is far above gasoline car discharge capacity.In addition, because diesel engine adopts the combustion system of lean-burn, oxygen enrichment, containing oxygen (about 5-13%) in tail gas, cause the NOx control techniques that the gasoline engines such as direct catalytic reduction, three-effect catalysis are conventional, be difficult to apply on a diesel engine.At present, generally acknowledge that SCR (Selective Catalytic Reduction-SCR) technology is the most efficient Diesel NOx purification techniques in the world, not only NOx purification efficiency is high for this technology, and by the complex optimum with engine, can also reduce complete machine oil consumption.
Current automobile-used SCR catalyst, its composition mostly is V
2o
5-WO
3(or MoO
3)-TiO
2-ceramic monolith, because moderate temperature catalytic performance is better, applies in a lot of country.But wherein as the V of main active component
2o
5highly toxic substance, along with its loss in SCR system use procedure will inevitably endanger Environmental security.Meanwhile, as the TiO of one of coating material
2cost is higher, and the Oxygen storage capacity of itself is also bad, is unfavorable for the further raising of loaded catalyst low-temperature SCR reacting catalytic performance.The feature of vanadia-based SCR catalysts is, have good NOx purifying property, but low temperature active is not good in delivery temperature more than 280 DEG C later, is difficult to adapt to the operation of diesel vehicle under road is crowded, the speed of a motor vehicle is slow, delivery temperature is low etc. condition.Therefore, adopt low toxicity developing material to have the low cost SCR catalyst of good low temperature catalytic performance, become the research and development focus of engine manufacturing.
Summary of the invention
The object of the invention is, provide a kind of be suitable for use for diesel engine, with cobalt-vanadium binary oxide type SCR supported catalyst, namely with cobalt-vanadium binary oxide for main active component, with cerium oxide, zirconia and γ-Al
2o
3some substitute TiO
2coating material, diesel engine nitrous oxides selectivity Catalytic Reducing Purification Catalysts and its preparation method.
The technical scheme adopted for realizing object of the present invention is:
(1) form main active component by cobalt-vanadium binary oxide, wherein cobalt, vanadium two kinds of elements are respectively with Co
2o
3and V
2o
5form exist, and Co
2o
3, V
2o
5mass percent be: 30 ~ 70%/70 ~ 30%, mass percent sum is 100%.
(2) by WO
3as co-catalyst.
(3) by CeO
2, ZrO
2, γ-Al
2o
3with Detitanium-ore-type TiO
2composition coating aid, the mass ratio of 4 kinds of oxides corresponds to respectively: 10 ~ 30%/0 ~ 20%/20 ~ 50%/20 ~ 50%, and mass percent sum is 100%, meanwhile, described CeO
2and ZrO
2mass percent sum be no more than 40%.
(4) γ-Al in coating aid
2o
3be made up of two parts: a part takes from pure matter γ-Al
2o
3powder; Another part is the γ-Al generated by transforming preparation as the Alumina gel of adhesive coating
2o
3.Wherein pure matter γ-Al
2o
3powder and Alumina gel transform the γ-Al generated
2o
3mass percent be: 50 ~ 75%/50 ~ 25%, mass percent sum is 100%.
(5) with the described cobalt-main active component of vanadium binary oxide, WO
3co-catalyst and by CeO
2, ZrO
2, γ-Al
2o
3with Detitanium-ore-type TiO
2the coating aid of composition, jointly form catalyst coatings, wherein the mass percent of main active component, co-catalyst and coating aid corresponds to respectively: 2 ~ 8%/5 ~ 20%/72 ~ 93%, and mass percent sum is 100%.
(6) use for diesel engine cobalt-vanadium binary oxide type SCR supported catalyst is formed by described catalyst coatings and 400 order cordierite honeycomb ceramic carriers, with the carrier that described 400 object cordierite honeycomb ceramics are described supported catalyst, further, by main active component (cobalt-vanadium binary oxide), co-catalyst (WO
3) and coating aid (CeO
2, ZrO
2, γ-Al
2o
3with Detitanium-ore-type TiO
2) percentage of the catalyst coatings gross weight that forms and cordierite honeycomb ceramic carrier weight is respectively: 10 ~ 30%/90 ~ 70%, mass percent sum is 100%.
The preparation method of use for diesel engine cobalt-vanadium binary oxide type SCR supported catalyst, its concrete technology comprises following four steps:
(1) determination of Kaolinite Preparation of Catalyst raw material dosage;
(2) preparation of coating paste presoma;
(3) preparation of coating paste;
(4) coating of coating paste.
The beneficial effect of feature of the present invention and generation is: the Co adopting low toxicity
2o
3substitute the V of high poison
2o
5, reduce the harm of catalyst to environment and human health, and the low-temperature SCR catalytic reaction that improve catalyst is active.CeO is added in catalyst coat
2, ZrO
2, enhance the Oxygen storage capacity of catalyst, further enhancing Co
2o
3to the improvement result of catalyst S CR low-temperature catalytic activity.Alumina gel is adopted to reduce the cost of material and technology difficulty of producing catalyst as adhesive coating; In addition, γ-Al
2o
3to Detitanium-ore-type TiO
2some substitute not only reduce cost of material, improve the low-temperature SCR reacting catalytic performance of catalyst, and the heat endurance of loaded catalyst is also improved to some extent.
Accompanying drawing explanation
Fig. 1 is SCR catalyst hot laboratory evaluation system schematic diagram.
Wherein: 1-single channel mass flow controller; 2-4 channel quality flow controller; 3-spinner flowmeter; 4-stop valve; 5-air flue; 6-mixing kettle; 7-steam producer; 8-reactor; 9-display temperature controller; 10-heating current display and control instrument; 11-peristaltic pump; 12-NH
3gas cylinder; 13-NO gas cylinder; 14-HC gas cylinder; 15-CO gas cylinder; 16-O
2/ N
2gaseous mixture gas cylinder, wherein O
2volume ratio be 10%, N
2volume ratio be 90%; 17-simulated exhaust gas entrance; 18-NH
3entrance; 19-steam entry; 20-reacts final vacuum outlet (towards gas analyzer).
Fig. 2 is for utilizing described catalyst activity laboratory evaluation system, and in the SCR reaction under embodiment 1 ~ 5 catalysis, NO purification efficiency is with the situation of change of reaction temperature.
Fig. 3 is SCR catalyst catalytic performance engine evaluation system schematic diagram.
Wherein: 21-dynamometer machine; 22-diesel engine; 23-inlet air flow gauge; 24-air inlet air conditioning; 25-NOx sensor; 26-reductant nozzle; 27-exhaust gas temperature sensor; 28-SCR catalyst converter; 29-injection of reducing agent amount of jet control system; 30-reducing agent storage tank; 31-ammonia analyzer; 32-exhaust gas sampling passage; 33-engine emission analyzer.
Fig. 4 for utilizing described catalytic performance engine evaluation system, when diesel exhaust gas temperature is 220 DEG C, during diesel exhaust gas SCR under embodiment 1 ~ 5 catalysis reacts, the purification efficiency of NOx.
Fig. 5 for utilizing described catalytic performance engine evaluation system, when diesel exhaust gas temperature is 350 DEG C, during diesel exhaust gas SCR under embodiment 1 ~ 5 catalysis reacts, the purification efficiency of NOx.
Detailed description of the invention
Below by way of specific embodiment also by reference to the accompanying drawings, technical scheme of the present invention is further described.It should be noted that described embodiment is narrative, but not determinate, the content that the present invention is contained is not limited to following embodiment.
Use for diesel engine cobalt-vanadium binary oxide type SCR supported catalyst, comprises cobalt-vanadium binary oxide, tungstic acid, cerium oxide, zirconia, γ-Al
2o
3, Detitanium-ore-type TiO
2and cordierite honeycomb ceramic carrier etc.
Form main active component by cobalt-vanadium binary oxide, wherein cobalt, vanadium two kinds of elements are respectively with Co
2o
3and V
2o
5form exist, and Co
2o
3and V
2o
5mass percent be: 30 ~ 70%/70 ~ 30%, mass percent sum is 100%.By WO
3as co-catalyst; By CeO
2, ZrO
2, γ-Al
2o
3with Detitanium-ore-type TiO
2composition coating aid, the mass ratio of above-mentioned 4 kinds of oxides is respectively: 10 ~ 30%/0 ~ 20%/20 ~ 50%/20 ~ 50%, and mass percent sum is 100%, and CeO
2and ZrO
2mass percent sum be no more than 40%.With the cobalt-main active component of vanadium binary oxide, WO
3co-catalyst and by CeO
2, ZrO
2, γ-Al
2o
3with Detitanium-ore-type TiO
2the coating aid of composition, forms catalyst coatings jointly.Wherein the mass percent of main active component, co-catalyst and coating aid corresponds to respectively: 2 ~ 8%/5 ~ 20%/72 ~ 93%, and mass percent sum is 100%.With 400 object cordierite honeycomb ceramics for supported catalyst agent carrier, use for diesel engine cobalt-vanadium binary oxide type SCR supported catalyst is formed, wherein by main active component (cobalt-vanadium binary oxide), co-catalyst (WO by described catalyst coatings and 400 order cordierite honeycomb ceramic carriers
3) and coating aid (CeO
2, ZrO
2, γ-Al
2o
3with Detitanium-ore-type TiO
2) percentage of the catalyst coatings gross weight that forms and cordierite honeycomb ceramic carrier weight is respectively: 10 ~ 30%/90 ~ 70%, mass percent sum is 100%.
γ-Al in coating aid
2o
3be made up of two parts: a part takes from pure matter γ-Al
2o
3powder; Another part is the γ-Al generated by transforming preparation as the Alumina gel of adhesive coating
2o
3, wherein pure matter γ-Al
2o
3powder and Alumina gel transform the γ-Al generated
2o
3mass percent be: 50 ~ 75%/50 ~ 25%, mass percent sum is 100%.
Embodiment 1
(1) determination of Kaolinite Preparation of Catalyst raw material dosage
Design needs Co in the main active component of Kaolinite Preparation of Catalyst
2o
3and V
2o
5mass ratio be: 66.7%:33.3%; The mass ratio of main active component, co-catalyst and coating aid is: 3%:9%:88%; CeO in coating aid
2, ZrO
2, γ-Al
2o
3with Detitanium-ore-type TiO
2mass ratio be: 20%:10%:20%:50%; Pure matter γ-Al in coating aid
2o
3powder and Alumina gel transform and generate γ-Al
2o
3mass ratio be: 50%:50%; The mass ratio of coating and carrier is 20%:80%.The 400 order cordierite honeycomb ceramic carriers planning to apply are 800g, can calculate the content of various component in described cobalt-vanadium binary oxide type SCR supported catalyst accordingly: Co
2o
34g, V
2o
52g, WO
318g, CeO
235.2g, ZrO
217.6g, pure matter γ-Al
2o
3γ-the Al that powder 17.6g, Alumina gel change into
2o
317.6g and Detitanium-ore-type TiO
2powder 88g, calculates the precursor material consumption of Kaolinite Preparation of Catalyst: Co (NO according to conversion scale
3)
26H
2o 14.0g, NH
4vO
32.6g, (NH
4)
10w
12o
41xH
2o 19.7g, Ce (NO
3)
36H
2o 88.8g and Zr (NO
3)
45H
2o 61.3g.Al in different model Alumina gel
2o
3content is different, for AS-200 type Alumina gel adhesive, and Al in this model Alumina gel
2o
3mass content is 10.8%, and the requirement calculating described model Alumina gel is 163.0g.
(2) preparation of coating paste presoma
Co (NO is taken by aforementioned fixed quality
3)
26H
2o, NH
4vO
3, (NH
4)
10w
12o
41xH
2o, Ce (NO
3)
36H
2o, Zr (NO
3)
45H
2o, and these five kinds of slaines and 33.2g oxalic acid are added in 2800ml deionized water be dissolved into mixed solution.To determine the pure matter γ-Al of quality
2o
3powder and Detitanium-ore-type TiO
2powder adds in mixed solution, and at 80 DEG C high degree of agitation 6h, by liquid evaporate to dryness after having stirred.Then at 100 DEG C, the powder after evaporate to dryness is dried 6h, then by this powder high-temperature roasting 2h at 600 DEG C.Product of roasting, after grinding, can obtain coating paste precursor powder.
(3) preparation of coating paste
Take the Alumina gel determining quality, and joined in 1630ml deionized water, then add the polyethylene glycol that 10g molecular weight is 20000, regulate the pH value of mixed solution for 3 ~ 4 with glacial acetic acid, then continue to stir the mixture to form homogeneous solution.In this solution, add the coating paste precursor powder prepared, then make coating paste precursor powder dispersed in a liquid by fierce stirring, namely obtain coating paste.
(4) coating of coating paste
Take the 400 order cordierite honeycomb ceramic carriers determining quality, after cleaning, drying, be immersed in the coating paste prepared.Take out and scribble the cordierite honeycomb ceramic carrier of slurry, blow off in the duct in and remain coating paste, dry 8h at 110 DEG C, then at 600 DEG C roasting 3h.Repeat the coating-drying-baking operation of coating paste, until coating slurry is used up, cobalt-vanadium binary oxide type SCR supported catalyst can be obtained.
Embodiment 2
(1) determination of Kaolinite Preparation of Catalyst raw material dosage
Design needs Co in the main active component of Kaolinite Preparation of Catalyst
2o
3and V
2o
5mass ratio be: 50%:50%; The mass ratio of main active component, co-catalyst and coating aid is: 2%:5%:93%; CeO in coating aid
2, ZrO
2, γ-Al
2o
3with Detitanium-ore-type TiO
2mass ratio be: 30%:0%:30%:40%; Pure matter γ-Al in coating aid
2o
3powder and Alumina gel transform and generate γ-Al
2o
3mass ratio be: 50%:50%; The mass ratio of coating and carrier is 30%:70%.The 400 order cordierite honeycomb ceramic carriers planning to apply are 700g, can calculate the content of various component in cobalt-vanadium binary oxide type SCR supported catalyst accordingly: Co
2o
33g, V
2o
53g, WO
315g, CeO
283.7g, pure matter γ-Al
2o
3γ-the Al that powder 41.85g, Alumina gel change into
2o
341.85g and Detitanium-ore-type TiO
2powder 111.6g, and the precursor material consumption calculating Kaolinite Preparation of Catalyst according to conversion scale: Co (NO
3)
26H
2o 10.5g, NH
4vO
33.9g, (NH
4)
10w
12o
41xH
2o 16.4g, Ce (NO
3)
36H
2o 211.1g and AS-200 type Alumina gel 387.5g.
(2) preparation of coating paste presoma
Co (NO is taken by aforementioned fixed quality
3)
26H
2o, NH
4vO
3, (NH
4)
10w
12o
41xH
2o, Ce (NO
3)
36H
2o, Zr (NO
3)
45H
2o, and these five kinds of slaines and 28.8g oxalic acid are added in 4800ml deionized water be dissolved into mixed solution.To determine the pure matter γ-Al of quality
2o
3powder and Detitanium-ore-type TiO
2powder adds in mixed solution, and at 60 DEG C high degree of agitation 8h, by liquid evaporate to dryness after having stirred.Then at 60 DEG C, the powder after evaporate to dryness is dried 12h, then by this powder roasting 3h at 500 DEG C.Product of roasting, after grinding, can obtain coating paste precursor powder.
(3) preparation of coating paste
Take the Alumina gel determining quality, and joined in 2000ml deionized water, then add the polyethylene glycol that 30g molecular weight is 20000, regulate the pH value of mixed solution for 3 ~ 4 with glacial acetic acid, then continue to stir the mixture to form homogeneous solution.In this solution, add the coating paste precursor powder prepared, then make coating paste precursor powder dispersed in a liquid by fierce stirring, namely obtain coating paste.
(4) coating of coating paste
Take the 400 order cordierite honeycomb ceramic carriers determining quality, after cleaning, drying, be immersed in the coating paste prepared.Take out and scribble the cordierite honeycomb ceramic carrier of slurry, blow off in the duct in and remain coating paste, dry 12h at 80 DEG C, then at 600 DEG C roasting 3h.Repeat the coating-drying-baking operation of coating paste, until coating slurry is used up, cobalt-vanadium binary oxide type SCR supported catalyst can be obtained.
Embodiment 3
(1) determination of Kaolinite Preparation of Catalyst raw material dosage
Design needs Co in the main active component of Kaolinite Preparation of Catalyst
2o
3and V
2o
5mass ratio be: 50%:50%; The mass ratio of main active component, co-catalyst and coating aid is: 8%:20%:72%; CeO in coating aid
2, ZrO
2, γ-Al
2o
3with Detitanium-ore-type TiO
2mass ratio be: 30%:0%:50%:20%; Pure matter γ-Al in coating aid
2o
3powder and Alumina gel transform and generate γ-Al
2o
3mass ratio be: 50%:50%; The mass ratio of coating and carrier is 10%:90%.The 400 order cordierite honeycomb ceramic carriers planning to apply are 900g, can calculate the content of various component in cobalt-vanadium binary oxide type SCR supported catalyst accordingly: Co
2o
34g, V
2o
54g, WO
320g, CeO
221.6g, pure matter γ-Al
2o
3γ-the Al that powder 18g, Alumina gel change into
2o
318g and Detitanium-ore-type TiO
2powder 14.4g, and the precursor material consumption calculating Kaolinite Preparation of Catalyst according to conversion scale: Co (NO
3)
26H
2o 14.0g, NH
4vO
35.1g, (NH
4)
10w
12o
41xH
2o21.9g, Ce (NO
3)
36H
2o 54.5g and AS-200 type Alumina gel 166.7g.
(2) preparation of coating paste presoma
Co (NO is taken by aforementioned fixed quality
3)
26H
2o, NH
4vO
3, (NH
4)
10w
12o
41xH
2o, Ce (NO
3)
36H
2o, Zr (NO
3)
45H
2o, and these five kinds of slaines and 38.2g oxalic acid are added in 2800ml deionized water be dissolved into mixed solution.To determine the pure matter γ-Al of quality
2o
3powder and Detitanium-ore-type TiO
2powder adds in mixed solution, and at 90 DEG C high degree of agitation 4h, by liquid evaporate to dryness after having stirred.Then at 120 DEG C, the powder after evaporate to dryness is dried 4h, then by this powder high-temperature roasting 3h at 550 DEG C.Product of roasting, after grinding, can obtain coating paste precursor powder.
(3) preparation of coating paste
Take the Alumina gel determining quality, and joined in 1000ml deionized water, then add the polyethylene glycol that 15g molecular weight is 20000, regulate the pH value of mixed solution for 3 ~ 4 with glacial acetic acid, then continue to stir the mixture to form homogeneous solution.In this solution, add the coating paste precursor powder prepared, then make coating paste precursor powder dispersed in a liquid by fierce stirring, namely obtain coating paste.
(4) coating of coating paste
Take the 400 order cordierite honeycomb ceramic carriers determining quality, after cleaning, drying, be immersed in the coating paste prepared.Take out and scribble the cordierite honeycomb ceramic carrier of slurry, blow residual liquid in duct off, dry 12h at 80 DEG C, then at 550 DEG C roasting 4h.Repeat the coating-drying-baking operation of coating paste, until coating slurry is used up, cobalt-vanadium binary oxide type SCR supported catalyst can be obtained.
Embodiment 4
(1) determination of Kaolinite Preparation of Catalyst raw material dosage
Design needs Co in the main active component of Kaolinite Preparation of Catalyst
2o
3and V
2o
5mass ratio be: 33.3%:66.7%; The mass ratio of main active component, co-catalyst and coating aid is: 3%:7%:90%; CeO in coating aid
2, ZrO
2, γ-Al
2o
3with Detitanium-ore-type TiO
2mass ratio be: 10%:20%:30%:40%; Pure matter γ-Al in coating aid
2o
3powder and Alumina gel transform and generate γ-Al
2o
3mass ratio be: 75%:25%; The mass ratio of coating and carrier is 20%:80%.The 400 order cordierite honeycomb ceramic carriers planning to apply are 800g, can calculate the content of various component in cobalt-vanadium binary oxide type SCR supported catalyst accordingly: Co
2o
32g, V
2o
54g, WO
314g, CeO
218g, ZrO
236g, pure matter γ-Al
2o
3γ-the Al that powder 40.5g, Alumina gel change into
2o
313.5g and Detitanium-ore-type TiO
2powder 72g, and the precursor material consumption calculating Kaolinite Preparation of Catalyst according to conversion scale: Co (NO
3)
26H
2o 7.0g, NH
4vO
35.1g, (NH
4)
10w
12o
41xH
2o 15.3g, Ce (NO
3)
36H
2o 45.4g, Zr (NO
3)
45H
2o 125.4g and AS-200 type Alumina gel 125g.
(2) preparation of coating paste presoma
Co (NO is taken by aforementioned fixed quality
3)
26H
2o, NH
4vO
3, (NH
4)
10w
12o
41xH
2o, Ce (NO
3)
36H
2o, Zr (NO
3)
45H
2o, and these five kinds of slaines and 24.2g oxalic acid are added in 3000ml deionized water be dissolved into mixed solution.To determine the pure matter γ-Al of quality
2o
3powder and Detitanium-ore-type TiO
2powder adds in mixed solution, and at 80 DEG C high degree of agitation 5h, by liquid evaporate to dryness after having stirred.Then at 100 DEG C, the powder after evaporate to dryness is dried 8h, then by this powder high-temperature roasting 2h at 600 DEG C.Product of roasting, after grinding, can obtain coating paste precursor powder.
(3) preparation of coating paste
Take the Alumina gel determining quality, and joined in 1250ml deionized water, then add the polyethylene glycol that 10g molecular weight is 20000, regulate the pH value of mixed solution for 3 ~ 4 with glacial acetic acid, then continue to stir the mixture to form homogeneous solution.In this solution, add the coating paste precursor powder prepared, then make coating paste precursor powder dispersed in a liquid by fierce stirring, namely obtain coating paste.
(4) coating of coating paste
Take the 400 order cordierite honeycomb ceramic carriers determining quality, after cleaning, drying, be immersed in the coating paste prepared.Take out and scribble the cordierite honeycomb ceramic carrier of slurry, blow residual liquid in duct off, dry 8h at 100 DEG C, then at 550 DEG C roasting 4h.Repeat the coating-drying-baking operation of coating paste, until coating slurry is used up, cobalt-vanadium binary oxide type SCR supported catalyst can be obtained.
Embodiment 5
(1) determination of Kaolinite Preparation of Catalyst raw material dosage
Design needs Co in the main active component of Kaolinite Preparation of Catalyst
2o
3and V
2o
5mass ratio be: 50%:50%; The mass ratio of main active component, co-catalyst and coating aid is: 5%:10%:85%; CeO in coating aid
2, ZrO
2, γ-Al
2o
3with Detitanium-ore-type TiO
2mass ratio be: 30%:0%:20%:50%; Pure matter γ-Al in coating aid
2o
3powder and Alumina gel transform and generate γ-Al
2o
3mass ratio be: 50%:50%; The mass ratio of coating and carrier is 15%:85%.The 400 order cordierite honeycomb ceramic carriers planning to apply are 850g, can calculate the content of various component in described cobalt-vanadium binary oxide type SCR supported catalyst accordingly: Co
2o
33.75g, V
2o
53.75g, WO
315g, CeO
238.25g, pure matter γ-Al
2o
3γ-the Al that powder 12.75g, Alumina gel change into
2o
312.75g and Detitanium-ore-type TiO
2powder 63.75g, and the precursor material consumption calculating Kaolinite Preparation of Catalyst according to conversion scale: Co (NO
3)
26H
2o 13.16g, NH
4vO
34.82g, (NH
4)
10w
12o
41xH
2o 16.4g, Ce (NO
3)
36H
2o 96.48g and AS-200 type Alumina gel 118.06g.
(2) preparation of coating paste presoma
Co (NO is taken by aforementioned fixed quality
3)
26H
2o, NH
4vO
3, (NH
4)
10w
12o
41xH
2o, Ce (NO
3)
36H
2o, Zr (NO
3)
45H
2o, and these five kinds of slaines and 35.96g oxalic acid are added in 2600ml deionized water be dissolved into mixed solution.To determine the pure matter γ-Al of quality
2o
3powder and Detitanium-ore-type TiO
2powder adds in mixed solution, and at 90 DEG C high degree of agitation 4h, by liquid evaporate to dryness after having stirred.Then at 100 DEG C, the powder after evaporate to dryness is dried 8h, then by this powder high-temperature roasting 2h at 600 DEG C.Product of roasting, after grinding, can obtain coating paste precursor powder.
(3) preparation of coating paste
Take the Alumina gel determining quality, and joined in 1000ml deionized water, then add the polyethylene glycol that 15g molecular weight is 20000, regulate the pH value of mixed solution for 3 ~ 4 with glacial acetic acid, then continue to stir the mixture to form homogeneous solution.In this solution, add the coating paste precursor powder prepared, then make coating paste precursor powder dispersed in a liquid by fierce stirring, namely obtain coating paste.
(4) coating of coating paste
Take the 400 order cordierite honeycomb ceramic carriers determining quality, after cleaning, drying, be immersed in the coating paste prepared.Take out and scribble the cordierite honeycomb ceramic carrier of slurry, blow residual liquid in duct off, dry 8h at 110 DEG C, then at 600 DEG C roasting 3h.Repeat the coating-drying-baking operation of coating paste, until coating slurry is used up, cobalt-vanadium binary oxide type SCR supported catalyst can be obtained.
Utilize the SCR catalyst hot laboratory evaluation system shown in Fig. 1, the NO SCR purifying property of above-described embodiment 1-5 is evaluated.Its test method is: in reactor 8, add catalyst 10mL.Be 9.5L/min, CO by the NO in the CO in the oxygen in steel cylinder 16, nitrogen mixed gas, steel cylinder 15, the propane in steel cylinder 14 and steel cylinder 13 according to oxygen, nitrogen mixed gas by 4 channel quality flow controllers 2 be 8.0mL/min, the flow velocity of propane to be 2.5mL/min, NO be 8.0mL/min enters respectively in mixing kettle 6 and mix, then mist enters in reactor 8 again.In adjustment steam producer 7, the growing amount of steam is 500mL/min, and is added in reactor by steam by steam entry 19.And the NH in steel cylinder 12
3gas, under the control of single channel quality controller 1, enters reactor 8 with the flow velocity of 8.0mL/min, and SCR catalytic reaction occurs the catalyst surface of the gaseous mixture flowed out with mixing kettle 6 in reactor 8.The experimental temperature scope of reactor is 150-550 DEG C, is controlled by display temperature controller 9.Reacted gaseous mixture enters after discharging from 20 mouthfuls and carries out NO concentration analysis regardless of light infrared analysis system.As calculated, under this experiment condition, in reactor 8, the air speed of SCR reaction is 60000h
-1.Utilize described catalyst activity laboratory evaluation system, under embodiment 1 ~ 5 catalysis SCR reaction in, NO purification efficiency with reaction temperature situation of change as shown in Figure 2.
Utilize the SCR catalyst reactive engine evaluation system shown in Fig. 3, the NOx selective catalytic reduction purifying property of above-described embodiment 1-5 is evaluated.Its test method is: need embodiment 1-5 to cut, be combined into 7L cylindrical load type catalyst before experiment, and carry out encapsulation process to described cutting, the cylindrical load type catalyst that is combined into.Use moment of torsion and the rotating speed of dynamometer machine 21 Control experiment engine (CY4102 diesel engine) 22, the ratio of adjustment engine exhaust flow and loaded catalyst volume is 60000h-1, and the delivery temperature successively controlling SCR catalyst central point is respectively 220 DEG C and 350 DEG C, carries out catalyst activity measurement.In test, measuring-signal is delivered to injection of reducing agent amount of jet control system 29 by NOx sensor (Siemens's NOx sensor) 25 and exhaust gas temperature sensor 27, calculate the injection dosage of reducing agent through single board computer wherein and corresponding software, and by adjustment reductant nozzle 26 dutycycle by the reducing agent urea solution in storage tank 30 by determining that metering sprays in gas extraction system.Enter in SCR catalyst 28 after the NH3 gas formed after urea decomposition mixes with the exhaust of engine 22 and carry out SCR catalytic reaction.The concentration of NOx and NH3 after reaction in gaseous mixture carries out quantitative analysis by engine emission analyzer 33 and ammonia analyzer 31 respectively.Utilize described catalytic performance engine evaluation system, when diesel exhaust gas temperature is respectively 220 DEG C and 350 DEG C, during the diesel exhaust gas SCR under embodiment 1 ~ 5 catalysis reacts, the purification efficiency of NOx respectively as shown in Figure 4 and Figure 5.
Claims (7)
1. use for diesel engine cobalt-vanadium binary oxide type SCR supported catalyst, comprises cobalt-vanadium binary oxide, tungstic acid, cerium oxide, zirconia, γ-Al
2o
3, Detitanium-ore-type TiO
2and cordierite honeycomb ceramic carrier, it is characterized in that: form main active component by cobalt-vanadium binary oxide, wherein cobalt, vanadium two kinds of elements are respectively with Co
2o
3and V
2o
5form exist, and Co
2o
3, V
2o
5mass percent be: 30 ~ 70%/70 ~ 30%, mass percent sum is 100%.
2., according to use for diesel engine cobalt according to claim 1-vanadium binary oxide type SCR supported catalyst, it is characterized in that: by WO
3as co-catalyst.
3., according to use for diesel engine cobalt according to claim 1-vanadium binary oxide type SCR supported catalyst, it is characterized in that: by CeO
2, ZrO
2, γ-Al
2o
3with Detitanium-ore-type TiO
2composition coating aid, and the mass ratio of described 4 kinds of oxides corresponds to respectively: 10 ~ 30%/0 ~ 20%/20 ~ 50%/20 ~ 50%, mass percent sum is 100%, wherein CeO
2and ZrO
2mass percent sum be no more than 40%.
4., according to the use for diesel engine cobalt described in claim 1 or 3-vanadium binary oxide type SCR supported catalyst, it is characterized in that :-the Al of γ described in coating aid
2o
3be made up of two parts, a part takes from pure matter γ-Al
2o
3powder, another part is the γ-Al generated by transforming preparation as the Alumina gel of adhesive coating
2o
3, wherein pure matter γ-Al
2o
3powder and Alumina gel transform the γ-Al generated
2o
3mass percent be: 50 ~ 75%/50 ~ 25%, mass percent sum is 100%.
5., according to the use for diesel engine cobalt described in claim 1 or 2 or 3-vanadium binary oxide type SCR supported catalyst, it is characterized in that: with described cobalt-vanadium binary oxide for main active component, WO
3for co-catalyst and by CeO
2, ZrO
2, γ-Al
2o
3with Detitanium-ore-type TiO
2the coating aid of composition, jointly form catalyst coatings, wherein, the mass percent of described main active component, co-catalyst and coating aid corresponds to respectively: 2 ~ 8%/5 ~ 20%/72 ~ 93%, and mass percent sum is 100%.
6. according to the use for diesel engine cobalt described in claim 1 or 5-vanadium binary oxide type SCR supported catalyst, it is characterized in that: with 400 object cordierite honeycomb ceramics for supported catalyst agent carrier, described use for diesel engine cobalt-vanadium binary oxide type SCR supported catalyst is formed, by cobalt-vanadium binary oxide, WO by described catalyst coatings and 400 order cordierite honeycomb ceramic carriers
3, CeO
2, ZrO
2, γ-Al
2o
3and Detitanium-ore-type TiO
2the catalyst coatings gross weight of composition and the percentage of cordierite honeycomb ceramic carrier weight are respectively: 10 ~ 30%/90 ~ 70%, and mass percent sum is 100%.
7., according to a preparation method for use for diesel engine cobalt according to claim 1-vanadium binary oxide type SCR supported catalyst, raw materials comprises: Co (NO
3)
26H
2o, NH
4vO
3, (NH
4)
10w
12o
41xH
2o, Ce (NO
3)
36H
2o, Zr (NO
3)
45H
2o, AS-200 type Alumina gel solution, pure matter γ-Al
2o
3powder, Detitanium-ore-type TiO
2powder, 400 order cordierite honeycomb ceramic carriers, oxalic acid, molecular weight are polyethylene glycol, glacial acetic acid and the deionized water of 20000, it is characterized in that: concrete technology comprises the following steps:
(1) determination of Kaolinite Preparation of Catalyst raw material dosage
With proportioning each described in claim 1 to 6, calculate Co in catalyst respectively
2o
3, V
2o
5, WO
3, CeO
2, ZrO
2, pure matter γ-Al
2o
3γ-the Al that powder, Alumina gel change into
2o
3, Detitanium-ore-type TiO
2the quality of powder and each constituent of cordierite honeycomb ceramic carrier; Again respectively according to every 582.1g Co (NO
3)
26H
2o produces 165.86g Co
2o
3; Every 233.96g NH
4vO
3produce 182.0g V
2o
5; Every 3042.58g (NH
4)
10w
12o
41xH
2o produces 2782.2g WO
3; Every 434.12gCe (NO
3)
36H
2o produces 172.11g CeO
2; Every 429.32g Zr (NO
3)
45H
2o produces 123.22g ZrO
2; Every 925.9gAS-200 type Alumina gel solution produces 100g γ-Al
2o
3ratio, converse needed raw material Co (NO
3)
26H
2o, NH
4vO
3, (NH
4)
10w
12o
41xH
2o, Ce (NO
3)
36H
2o, Zr (NO
3)
45H
2the quality of O and AS-200 type Alumina gel solution;
(2) preparation of coating paste presoma
Co (NO is taken by described fixed quality
3)
26H
2o, NH
4vO
3, (NH
4)
10w
12o
41xH
2o, Ce (NO
3)
36H
2o, Zr (NO
3)
45H
2o, and be Co (NO by described five kinds of slaines and quality
3)
26H
2o and NH
4vO
3the oxalic acid that gross mass is 2 times, add according to every 1g slaine add 15 ~ 30ml deionized water ratio weigh deionized water in be dissolved into mixed solution; To determine the pure matter γ-Al of quality
2o
3powder and Detitanium-ore-type TiO
2powder adds in mixed solution, and at 60 ~ 90 DEG C high degree of agitation 4-8h, by liquid evaporate to dryness after having stirred; Then at 60 ~ 120 DEG C, the powder after evaporate to dryness is dried 4 ~ 12h, then by this powder high-temperature roasting 2 ~ 3h at 500 ~ 600 DEG C; Product of roasting, after grinding, can obtain coating paste precursor powder;
(3) preparation of coating paste
Take the Alumina gel determining quality, and joined according to every 1g Alumina gel add 5 ~ 10ml deionized water ratio weigh deionized water in be dissolved into mixed solution; Add according to coating gross mass 5 ~ 15% ratio the polyethylene glycol that molecular weight is 20000 again, then regulate the pH value of mixed solution for 3 ~ 4 with glacial acetic acid, continue to stir described mixture to form homogeneous solution; In this solution, add the coating paste precursor powder prepared, then make coating paste precursor powder dispersed in a liquid by fierce stirring, namely obtain coating paste;
(4) coating of coating paste
Take the 400 order cordierite honeycomb ceramic carriers determining quality, after cleaning, drying, be immersed in the coating paste prepared; Take out the cordierite honeycomb ceramic carrier scribbling slurry, blow residual liquid in duct off, dry 6 ~ 12h at 80 ~ 120 DEG C, high-temperature roasting 3 ~ 5h at 500 ~ 600 DEG C again, repeat the coating-drying-baking operation of described coating paste, until coating slurry is used up, cobalt-vanadium binary oxide type SCR supported catalyst can be obtained.
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