CN1171683C - Coating method of automobile tail gas purifying catalyst - Google Patents
Coating method of automobile tail gas purifying catalyst Download PDFInfo
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- CN1171683C CN1171683C CNB021039011A CN02103901A CN1171683C CN 1171683 C CN1171683 C CN 1171683C CN B021039011 A CNB021039011 A CN B021039011A CN 02103901 A CN02103901 A CN 02103901A CN 1171683 C CN1171683 C CN 1171683C
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Abstract
The present invention discloses a method for coating automobile exhaust gas purifying catalysts, which comprises: serous fluid which comprises noble metal automobile exhaust gas purifying catalysts is coated on a cordierite honeycomb carrier processed with a non-ionic surfactant solution. A catalyst coating adopting the coating method has the advantages of hard cracking and peeling-off and less coating loss.
Description
Technical field
The invention relates to a kind of painting method of catalyst, further say so about a kind of painting method of cleaning catalyst for tail gases of automobiles.
Background technology
Along with the promulgation of Environmental Protection in China rules and progressively strict, it is to administer the highly effective external purification means of motor vehicle exhaust emission that cleaning catalyst for tail gases of automobiles is installed, the purifying vehicle exhaust effect how, closely related with bond strength of catalyst coat and carrier etc., only guaranteed catalyst coat difficult drop-off just can make attached to its lip-deep noble metal continuously effective ground harmful substance is catalytically conveted to innocuous substance.
The durability of carrier preliminary treatment and catalyst coat is closely related, if carrier and Bond Strength of Coating are low, coating easily chaps, peels off, and will directly influence catalytic activity.Thereby to choosing of carrier preliminary treatment and coating processes be improve carrier and anchoring strength of coating, improve the coating microstructure, the key of raising catalytic activity and durability, also be the key of whole technology of preparing.
The disclosed method of JP59039346 is to use organic polymer aqueous solution precoatings such as polyethylene, polypropylene, polystyrene, polyurethane, polyvinyl alcohol or cellulose derivative earlier, applies activated alumina afterwards.The deficiency of this method is that organic polymer is not modified, and does not bring into play the effect that it strengthens intensity between catalyst coat and carrier as yet.
The method that discloses among the JP56124442 does not relate to the content of modified organic polymers precoating, just with containing unmodified polyethylene alcohol, ZrO
2, CeO
2, pure Al
2O
3The salt solution impregnation honeycomb substrate of (aluminum nitrate), magnesium aluminate spinel and Pt, Pd.
The preparation method of disclosed catalyst-coated slurry among the CN1103010 does not include the content of organic polymer precoating, is intending the thin dried glue (Al of water
2O
33H
2O), ceria, talcum powder, rare nitric acid and 5% polyvinyl alcohol simultaneously ball milling form glue, directly cure after the vacuum covering, afterwards dipping 2-60 minute and cure preparation in Cu, La nitrate and among the Pt, the Rh aqueous solution respectively.Organic polymer in this method does not relate to the modification preliminary treatment, and catalyst coat divided for three steps finished, and at first the coated catalysts carrier floods base metal and noble metal afterwards respectively.
We find that in the catalyst-coated method that is provided in the prior art, resulting coating easily chaps and peels off, and causes the loss of measuring on the catalyst coat.
Technical scheme
It is little to the purpose of this invention is to provide on a kind of coating the amount loss, is difficult for be full of cracks and the method for the coating cleaning catalyst for tail gases of automobiles that peels off.
Painting method provided by the invention comprises the steps:
(1) with non-ionic surface active agent as a weight, add the deionized water dissolving of 9 parts of-99 parts of weight, add a kind of acid for adjusting pH and be 0.5-6.0 or add a kind of alkali that to regulate pH be 7.5-9.5, obtain modified solution;
(2) with the modified solution dipping cordierite honeycomb carrier that obtains, 90-130 ℃ after dry 1-5 hour, cleaning catalyst for tail gases of automobiles is mixed with deionized water, regulate pH=1-7, wet ball grinding is the heavy % of solid content 20-45, and grain diameter is the slurry of 1-10 μ m, applies with this slurry, make to measure on the catalyst and reach the heavy % of 10-25, drying and roasting.
In the painting method provided by the invention, said cleaning catalyst for tail gases of automobiles, it is the cleaning catalyst for tail gases of automobiles that adopts prior art for preparing, they can adopt disclosed patented technology to prepare, for example at the catalyst described in the disclosed technological documents such as CN1239017A, CN1103010A or US5081095.
In the painting method provided by the present invention, said non-ionic surface active agent is meant and does not generate ion in water in the step (1), the surfactant that polyhydroxy or polyoxyethylene groups isoreactivity gene are arranged in the molecule, this surfactant is all more stable to bronsted lowry acids and bases bronsted lowry, mainly contains polyalcohol type and polyoxyethylene-type.Preferred nonionic is one or more the mixture in polyethylene glycol, glycerine, carboxymethyl cellulose, polyvinyl alcohol or the polyacrylic acid.
The acid that being used to described in the step (1) regulated pH is selected from one of formic acid, acetate, hydrochloric acid, citric acid, phosphoric acid or nitric acid or its mixture; The described alkali that is used to regulate pH is selected from ammoniacal liquor, sodium carbonate or and one of NaOH or its mixture.
The painting method of cleaning catalyst for tail gases of automobiles provided by the present invention applies effect by the evaluation of aqueous vapor erosion test.This method is the carrier that takes by weighing a certain amount of coated catalysts with the one thousandth balance, with air purge 5-15 minute of 5atm, use the identical time of water erosion of 1000-2000 ml/min, pH=5-8 afterwards, use 5atm again air purge 5-15 minute, 90-130 ℃ of oven dry, 500-700 ℃ roasting 1-3 hour, use the weight of carrier behind the one thousandth balance weighing aqueous vapor erosion test again, with η (%)=(1-W
After/ W
Before) * 100% calculates amount loss rate on the catalyst coat, wherein, and W
BeforeBe the weight (g) of carrier before the erosion experiment, W
AfterWeight (g) for erosion experiment back carrier.
The painting method of cleaning catalyst for tail gases of automobiles provided by the present invention, than the painting method that prior art provided, the catalyst coat of gained is not seen be full of cracks and peeling phenomenon, the amount loss is littler on the coating.For example, amount is lost in 2.5-2.8% on the painting method coating provided by the invention, and adopts prior art to apply, and the amount loss is up to 23.0-56.3% on the catalyst coat of gained.From to the stereoscan photograph of catalyst coat as can be seen, the resulting catalyst coat of painting method provided by the invention surface does not have crack performance to occur, and there is tangible be full of cracks on the catalyst coat surface of adopting prior art to apply.
Description of drawings
Fig. 1 is the stereoscan photograph of the catalyst coat that obtains through example 7 processes.
Fig. 2 is the stereoscan photograph of the catalyst coat that obtains through Comparative Examples 1 process.
The specific embodiment
The present invention is further illustrated below by example.
The preparation process of the cleaning catalyst for tail gases of automobiles slurries of prior art for preparing is adopted in example 1-3 explanation.
Example 1
Disclosed technology prepares the process of catalyst slurry among this example explanation CN1239017A.
In 500 milliliters of there-necked flasks, add and add 8 gram LaCl under 250 ml deionized water, the stirring
3XH
2O, 10 gram (NH
4)
2Ce (NO
3)
6Make it to dissolve fully.Add ammoniacal liquor under the room temperature, adjust its pH=9, wait to precipitate fully, be warming up to 95 ℃, aging slurries are 1 hour under this temperature, filter, wash the gained filter cake to there not being acid group, and the mixture that gets lanthanum, cerium hydroxide is stand-by.
Get 113 gram boehmites (alumina content is 33 heavy %, and the Shandong catalyst plant is produced) and add deionized water, stirred 30 minutes, be made into the slurries that solid content is 14wt%, adding 1: 1 hydrochloric acid adjusted value is pH=2.8; Adding the above-mentioned mixture that is prepared into lanthanum, cerium hydroxide continues to stir; Under agitation continue to add 113 gram boehmites and 20 gram aluminium colloidal sols (alumina content is 22 heavy %, and the Shandong catalyst plant is produced), continue to stir, make slurries be uniform colloid shape.70 ℃ aging 1 hour, 120 ℃ of dryings 2 hours, 600 ℃ of roasting temperatures 2 hours make modified aluminas.
Press example 8 among the CN1239017A (modified aluminas of example 4 preparations among the CN1239017A) preparation catalyst.With the platinum acid chloride solution of 13.5 milliliters of platiniferous 0.02082 grams per milliliters dipping 30 restrain modified aluminas, then 120 ℃ dry 2 hours down, and, make base coating material 600 ℃ of following roastings 2 hours.
The base coating material that makes is put in the ball mill with 70 gram deionized water mixing wet-millings made slurries in 4 hours.With external diameter is that 20 millimeters, length are 33 millimeters, the sectional area cordierite honeycomb carrier that contains 0.23 millimeter of 300 airflow hole, wall thickness immerses in these slurries per square inch, from slurries, take out again, after blowing away slurries unnecessary in the hole with compressed air, 120 ℃ of dryings 4 hours, 300 ℃ of roastings 2 hours make catalyst.
Example 2
Disclosed method prepares the process of catalyst slurry among this example explanation employing CN1103010A.
1. intend dried glue 1000 grams of thin water aluminium, talcum powder 70 grams, ceria (CeO
2) 80 grams, 100 milliliters of 5% diluted nitric acid aqueous solutions, 200 milliliters of 5% polyvinyl alcohol water solutions, 1500 milliliters of ball millings of distilled water become gluing solution.
2. taking by weighing 1449.6 gram copper nitrates and 1229.0 gram lanthanum nitrates, to be dissolved into 2.51 aqueous solution stand-by.
3. take by weighing the Pt400 milligram, remove nitrate anion with a small amount of chloroazotic acid heating for dissolving after, with distilled water diluting to 260 milliliter, perhaps take by weighing chloroplatinic acid 1060m gram and be dissolved into 260 ml water solution for later use.
4. the method for supported catalyst: earlier with glue coated carrier in 1., 120 ℃ of oven dry 2 hours, 800 ℃ of roastings 3 hours; This carrier of solution impregnation in using then 2., 120 ℃ of oven dry 2 hours, 800 ℃ of roastings 3 hours; This carrier of solution impregnation in using was 3. at last dried 2 hours for 80-120 ℃, and roasting is 2 hours in 500 ℃ of air atmospheres.The carrier that makes constant temperature 2 hours in 400 ℃ of hydrogen or hydrogen/nitrogen (volume ratio 1: 1).
Example 3
The explanation of this example prepares the process of catalyst with disclosed method among the US5081095.
1. 3000 restrain cerous carbonate Ce
2(CO
3)
3Solution (35% water) with 1569 gram glacial acetic acid reactions, makes cerous acetate.Drying, and, make the high specific surface cerium 425 ℃ of roastings 2 hours (being connected with 30 cubic feet/min air).
2. prepare slurries, contain 428 gram γ-Al
2O
3, 22 grams, one water aluminium oxide, the high specific surface cerium that 122 grams make in 1., the 97 gram cerous acetates, 10 gram glacial acetic acid and the 571 gram water that make with method in 1..These slurries contain the oxide of the 50 heavy % that have an appointment.
3. the amine mixed aqueous solution for preparing chlorination Pt and Rh.
4. the method for supported catalyst: with slurries coated carrier in 2., roasting is 1 hour in 8 hours 427 ℃ of air atmospheres of 120 ℃ of oven dry; This carrier of solution impregnation in using again 3. makes its load about 0.0038 ounce metal Pt and Rh, 427 ℃ of roastings 1 hour.
Example 4
The preparation method of this example explanation cordierite honeycomb carrier preprocessing solution.
(1) in 3000 milliliters beaker, claims 200 gram polyvinyl alcohol (Beijing Chemical Plant, the degree of polymerization 1000), add deionized water and make it be dissolved as the unmodified polyethylene alcoholic solution that concentration is 2 heavy %.
(2) in above-mentioned solution, add concentrated hydrochloric acid, obtain the modified poly ethylene alcoholic solution of pH=2 after the dissolving.
Example 5
(1) polyvinyl alcohol in the example 4 is changed into glycerine (chemical pure, Beijing Chemical Plant), concentration is 4 heavy %; (2) add formic acid, obtain the modification glycerine solution of pH=4.Other with example 4 in identical.
Example 6
(1) polyvinyl alcohol in the example 4 is changed into carboxymethyl cellulose (chemical pure, Beijing Chemical Plant), concentration is 6 heavy %; (2) add ammoniacal liquor, obtain the modified carboxy methyl cellulose solution of pH=8.Other with example 4 in identical.
Example 7
Get 20 gram cordierite honeycomb carriers (Corning Incorporated, 400 hole/square feet), dipping is 5 minutes in the modified poly ethylene alcoholic solution of example 4 preparations, oven dry.After applying with the catalyst slurry of example 1 preparation, 130 ℃ of oven dry, 650 ℃ of roastings 2 hours.
Coating effect by aqueous vapor erosion test evaluation catalyst:
After the air purge catalyst of 5atm 10 minutes, use the identical time of water erosion of 1500 ml/min, pH=6.8 instead, use the air purge catalyst 10 minutes of 5atm again, 130 ℃ of oven dry, 650 ℃ of roastings 2 hours, with the weight of the honeycomb substrate of the forward and backward coated catalysts of one thousandth balance weighing aqueous vapor erosion test, according to formula η (%)=(1-W
After/ W
Before) * 100% calculates amount loss rate on the catalyst coat, in the formula, and W
Before: the weight (g) of carrier before the erosion experiment, W
After: the weight (g) of erosion experiment back carrier is calculated amount loss η on the catalyst coat
1
The analysis of catalyst coat surface topography is carried out with the ISI-60 ESEM that American I Si Corporation produces, and analysis condition is: accelerating potential 20KV, inclination angle 30, operating distance 15mm.
The stereoscan photograph of surface topography is seen shown in Figure 1.
Comparative Examples 1
Get 20 gram cordierite honeycomb carriers, the unmodified polyethylene alcoholic solution that in the base coating material slurries of example 1 preparation, adds preparation in the example 4 (1), method by example 1 applies again, 130 ℃ of oven dry, 650 ℃ of roasting 2h, after the air purge catalyst of 5atm 10 minutes, use 1500 ml/min instead, the identical time of water erosion of pH=6.8, use the air purge catalyst 10 minutes of 5atm again, 130 ℃ of oven dry, 650 ℃ of roasting 2h are before one thousandth balance weighing aqueous vapor erosion test, the honeycomb substrate weight of back coated catalysts is calculated amount loss η on the catalyst coat
2
The stereoscan photograph of surface topography is seen shown in Figure 2.
Comparative Examples 2
Get 20 gram cordierite honeycomb carriers, in example 4 (1), flooded 5 minutes oven dry in the unmodified polyethylene alcoholic solution of preparation.The method for preparing catalyst with example 1 applies, 130 ℃ of oven dry, 650 ℃ of roasting 2h, after the air purge catalyst of 5atm 10 minutes, the identical time of water erosion of using 1500 ml/min, pH=6.8 instead, use the air purge catalyst 10 minutes of 5atm again, 130 ℃ of oven dry, 650 ℃ of roasting 2h, the weight of the honeycomb substrate of the forward and backward coated catalysts of usefulness one thousandth balance weighing aqueous vapor erosion test is calculated amount loss η on the catalyst coat
3
The surface topography of the coated catalyst coat of this Comparative Examples has the feature of Fig. 2.
Example 8
Get 20 gram cordierite honeycomb carriers, in example 5 (2), flooded 5 minutes oven dry in the modification glycerine solution of preparation.Apply with the 4. middle disclosed supported catalyst agent method of describing of CN1103010A of example 2,130 ℃ of oven dry, 650 ℃ of roasting 2h, after the air purge catalyst of 5atm 10 minutes, the identical time of water erosion of using 1500 ml/min, pH=6.8 instead, use the air purge catalyst 10 minutes of 5atm again, 130 ℃ of oven dry, 650 ℃ of roasting 2h with the honeycomb substrate weight of the forward and backward coated catalysts of one thousandth balance weighing aqueous vapor erosion test, calculate amount loss η on the catalyst coat
4
The surface topography of the coated catalyst coat of this example has the feature of Fig. 1.
Comparative Examples 3
Get the homemade cordierite honeycomb carrier of 20 grams, the unmodified glycerine solution that adds example 5 (1) preparations in the slurries in example 2, apply by the disclosed supported catalyst agent method of describing in the example 2 of CN1103010A again, 130 ℃ of oven dry, 650 ℃ of roasting 2h, after the air purge catalyst of 5atm 10 minutes, use 1500 ml/min instead, the identical time of water erosion of pH=6.8, use the air purge catalyst 10 minutes of 5atm again, 130 ℃ of oven dry, 650 ℃ of roasting 2h are before one thousandth balance weighing aqueous vapor erosion test, the weight of the honeycomb substrate of back coated catalysts is calculated amount loss η on the catalyst coat
5
The surface topography of the coated catalyst coat of this Comparative Examples has the feature of Fig. 2.
Comparative Examples 4
Get the homemade cordierite honeycomb carrier of 20 grams, in example 5 (1), flooded 5 minutes oven dry in the unmodified glycerine solution of preparation.Apply with the disclosed supported catalyst agent method of describing in the example 2 of CN1103010A, 130 ℃ of oven dry, 650 ℃ of roasting 2h, after the air purge catalyst of 5atm 10 minutes, the identical time of water erosion of using 1500 ml/min, pH=6.8 instead, use the air purge catalyst 10 minutes of 5atm again, 130 ℃ of oven dry, 650 ℃ of roasting 2h, the weight of the carrier honeycomb substrate of the forward and backward coated catalysts of usefulness one thousandth balance weighing aqueous vapor erosion test is calculated amount loss η on the catalyst coat
6
The surface topography of the coated catalyst coat of this Comparative Examples has the feature of Fig. 2.
Example 9
Get 20 gram cordierite honeycomb carriers, dipping is 5 minutes in the modified carboxy methyl cellulose solution of example 6 preparations, apply with the 4. middle disclosed supported catalyst agent method of describing of US5081095 of example 3 again after the oven dry, 130 ℃ of oven dry, 650 ℃ of roasting 2h, after the air purge catalyst of 5atm 10 minutes, use 1500 ml/min instead, the identical time of water erosion of pH=6.8, use the air purge catalyst 10 minutes of 5atm again, 130 ℃ of oven dry, 650 ℃ of roasting 2h are before one thousandth balance weighing aqueous vapor erosion test, the weight of the honeycomb substrate of back coated catalysts is calculated amount loss η on the catalyst coat
7
The surface topography of the coated catalyst coat of this example has the feature of Fig. 1.
Comparative Examples 5
Get 20 gram cordierite honeycomb carriers, the unmodified carboxymethyl cellulose that in the slurries that example 3 is described, adds preparation in the example 6 (1), apply with the disclosed supported catalyst agent method of US5081095 again, 130 ℃ of oven dry, 650 ℃ of roasting 2h, after the air purge catalyst of 5atm 10 minutes, use 1500 ml/min instead, the identical time of water erosion of pH=6.8, use the air purge catalyst 10 minutes of 5atm again, 130 ℃ of oven dry, 650 ℃ of roasting 2h are before one thousandth balance weighing aqueous vapor erosion test, the weight of the honeycomb substrate of back coated catalysts is calculated amount loss η on the catalyst coat according to formula
8
The surface topography of the coated catalyst coat of this Comparative Examples has the feature of Fig. 2.
Comparative Examples 6
Get 20 gram cordierite honeycomb carriers, dipping is 5 minutes in the unmodified cmc soln of example 6 (1) preparations, oven dry.Apply with the disclosed supported catalyst agent method of describing in the example 3 of US5081095,130 ℃ of oven dry, 650 ℃ of roasting 2h, after the air purge catalyst of 5atm 10 minutes, the identical time of water erosion of using 1500 ml/min, pH=6.8 instead, use the air purge catalyst 10 minutes of 5atm again, 130 ℃ of oven dry, 650 ℃ of roasting 2h, the weight of the honeycomb substrate of the forward and backward coated catalysts of usefulness one thousandth balance weighing aqueous vapor erosion test is calculated amount loss η on the catalyst coat
9
The surface topography of the coated catalyst coat of this Comparative Examples has the feature of Fig. 2.
Table 1
Examples comparative contrast contrast contrast contrast contrast
7 8 9
Numbering example 1 example 2 examples 3 examples 4 examples 5 examples 6
Coating η
1η
2η
3η
4η
5η
6η
7η
8η
9
Last amount
Lose 2.5 54.8 25.5 2.8 55.0 26.5 2.6 56.3 23.0
(％)
Claims (4)
1, a kind of method that applies cleaning catalyst for tail gases of automobiles, be that cleaning catalyst for tail gases of automobiles is added deionized water, make the heavy % solid content of 20-45, after wet ball grinding is the slurry of 1-10 μ m to grain diameter, be coated on the cordierite honeycomb carrier, make to measure on the catalyst and reach the heavy % of 10-25, and obtain through conventional dry and roasting, it is characterized in that the said cordierite honeycomb carrier of this method carries out preliminary treatment with nonionic surfactant solution, said nonionic surfactant solution is as a weight with non-ionic surface active agent, the deionized water dissolving that adds 9 parts of-99 parts of weight adds a kind of acid for adjusting pH and is 0.5-6.0 or add a kind of alkali and regulates pH and obtain behind the 7.5-9.5.
2, in accordance with the method for claim 1, it is characterized in that wherein said non-ionic surface active agent is selected from one or more the mixture in polyethylene glycol, glycerine, carboxymethyl cellulose, polyvinyl alcohol or the polyacrylic acid.
3, in accordance with the method for claim 1, it is characterized in that the described acid that is used to regulate pH is selected from one of formic acid, acetate, hydrochloric acid, citric acid, phosphoric acid or nitric acid or its mixture.
4, in accordance with the method for claim 1, it is characterized in that the described alkali that is used to regulate pH is selected from ammoniacal liquor, sodium carbonate or and one of NaOH or its mixture.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB021039011A CN1171683C (en) | 2002-02-07 | 2002-02-07 | Coating method of automobile tail gas purifying catalyst |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB021039011A CN1171683C (en) | 2002-02-07 | 2002-02-07 | Coating method of automobile tail gas purifying catalyst |
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| Publication Number | Publication Date |
|---|---|
| CN1436599A CN1436599A (en) | 2003-08-20 |
| CN1171683C true CN1171683C (en) | 2004-10-20 |
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|---|---|---|---|
| CNB021039011A Expired - Lifetime CN1171683C (en) | 2002-02-07 | 2002-02-07 | Coating method of automobile tail gas purifying catalyst |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9662636B2 (en) | 2014-04-17 | 2017-05-30 | Basf Corporation | Zoned catalyst composites |
| CN105597750B (en) * | 2016-01-06 | 2017-12-29 | 中自环保科技股份有限公司 | A kind of flawless three-way catalyst coating paste, catalyst and preparation method thereof |
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2002
- 2002-02-07 CN CNB021039011A patent/CN1171683C/en not_active Expired - Lifetime
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