CN101927171A - Tail gas purification catalyst for gas fuel engine and preparation method thereof - Google Patents

Abstract

The invention discloses a tail gas purification catalyst for a gas fuel engine and a preparation method thereof. A combustible gas serving as an alternative fuel for the engine has the advantages of high storage efficiency, good automotive dynamic performance, high cost performance, lower pollution emission and the like, therefore an automobile with a gas fuel engine is a tendency of automobile industrial development. The combustible gas has unique properties, so purification catalysis of the burned tail gas requires good low-ignition temperature and good high-temperature stability. In terms of per liter of a metal honeycomb carrier, the tail gas purification catalyst comprises the following components by weight: 50-120g of gamma-Al2O3, 8-20g of rare-earth metal oxide, 1-10g of transition metal oxide, 0.5-5g of alkaline-earth metal oxide and 0.5-1.5g of noble metal. The tail gas purification catalyst prepared by the components has good low-ignition temperature and good high-temperature stability; and the exhaust emission of the engine conforms to Euro IV Emission Standard.

Description

Tail gas purification catalyst for gas fuel engine and preparation method thereof

Technical field

What the present invention relates to is a kind of tail gas purification catalyst for gas fuel engine and preparation method thereof.

Background technology

Automobile engine is based on petroleum based fuels substantially, discharge during automobile engine work and contain toxic gases such as CO, CH, NOx in a large number, pollutant atmosphere greatly is not though electric jet technology and the extensive use of three-element catalytic transformation technology at present also tackles the problem at its root; In recent years, people are in research and adopt all gases fuel to replace the fuel of petroleum based fuels as automobile engine, these gases comprise natural gas, liquefied petroleum gas, coal gas or the like, these fuel gas have the storage efficiency height as engine replacing fuel, automobile dynamic quality is good, ratio of performance to price height, advantages such as disposal of pollutants is lower, the gaseous propellant engine automobile will be the direction of automobile industry development, and China is the country of a petroleum resources shortage, and the fuel gas aboundresources, along with the construction of West-East National Gas Transmission Project, the development of gaseous propellant engine has more realistic meaning.

Fuel gas has compared with gasoline as engine fuel that some is different: 1. the fuel gas composition mainly is a methane, and methane is the most dysoxidizable compound of hydrocarbon compound, is difficult to the methane gas conversion ratio that reaches high with the three-way catalyst of gasoline automobile; 2. the octane number height of fuel gas, burning velocity is different from gasoline, and temperature height in the cylinder requires the tail gas reforming catalyst high temperature resistant, and changing capability is strong; 3. mixture strength is different from gasoline during three-way catalyst maximum conversion efficient, and the former air-fuel ratio is near 17.1, and the latter is near 14.7; 4. ignition energy is higher than gasoline during gas fuel burning.Therefore require the tai-gas clean-up catalyst of flame engine to have good low light-off temperature and high-temperature stability.

Summary of the invention

Purpose of the present invention just provides a kind of tail gas purification catalyst for gas fuel engine, solves existing petrolic tai-gas clean-up catalyst to the unfavorable problem of the exhaust purification catalytic of gaseous propellant engine.

Another object of the present invention just provides the preparation method that the gaseous propellant engine tail gas clean-up is urged agent.

The object of the present invention is achieved like this: tail gas purification catalyst for gas fuel engine is the component that contains following weight number in every liter of metal beehive carrier: γ-Al ₂O ₃50-120g, rare-earth oxide 8-20g, transition metal oxide 1-10g, alkaline earth oxide 0.5-5g, noble metal 0.5-1.5g; Described metal beehive carrier is prepared from by the siderochrome aluminum slice, and described siderochrome aluminum slice contains the chemical composition of following percentage by weight, and wherein C is 0.015-0.001%, Si is 0.8-0.1%, and Mn is 0.8-0.1%, and Al is 9.0-2.0%, Cr is 31-10%, and La is 0.15-0.01%; Siderochrome aluminum slice thickness is 0.01-0.15mm, the smooth surface no concave-convex.

Described rare-earth oxide is La ₂O ₃, CeO ₂, Y ₂O ₃, Nd ₂O ₃In two or more any combination, transition metal oxide is ZrO ₂, TiO ₂, one or more any combination among NiO, CoO, the CuO, alkaline earth oxide is one or more any combination among BaO, SrO, CaO, the MgO, noble metal is one or more any combination among Pt, Pd, the Rh.

Its preparation method may further comprise the steps:

(1) gets the rare-earth oxide of above-mentioned formula ratio, transition metal oxide, alkaline earth oxide is mixed with three kinds of solution with 1 nitrate that is 65-70% than amount and the concentration of 3-6 respectively, three kinds of solution merges and mixes with the equivalent deionized water and obtains mixed solution, and mixed solution is the limit stirring in mixed process, the limit dropping ammonia, accent PH is 9-12, obtain precipitation, suction filtration gets filter cake;

(2) equal 1 with mixed solution than aluminium colloidal sol: 10-20 and mixed solution equal 1 than polyvinyl alcohol: the amount of 10-20, get the γ-Al of commercially available aluminium colloidal sol and polyvinyl alcohol and formula ratio ₂O ₃Mix, be made into the active oxidation aluminum slurry, the filter cake that step (1) is obtained adds, and in ball mill ball milling 24-56 hour, obtains the mixed slurry of uniform particle size;

(3) the siderochrome aluminum slice is prepared into metal beehive carrier according to a conventional method, on the surface of one liter of metal beehive carrier, above-mentioned mixed slurry in the coating, under 130-180 ℃ of condition dry 3-5 hour then, calcining 3-5 hour under 500-1000 ℃ of condition again;

(4) get formula ratio noble metal and watery hydrochloric acid and be mixed with the precious metal salt acid salt solution that bullion content is 20-50%, the metal beehive carrier that calcining is good floods in the precious metal salt hydrochlorate fully, then under the 130-180 ℃ of condition dry 3-5 hour, roasting 3-5 hour promptly under 500-1000 ℃ of condition.

Take the present invention of above-mentioned measure, cheap, under normal condition, have good low light-off temperature, and high-temperature stability.Behind 1050 ℃, 24 hours senile experiment, be that the volumn concentration of CO is 1.35% in simulation gas, CH ₄Content is 0.25%, and Nox content is 0.2%, O ₂Content is 4.2%, CO ₂Content is 6%, N ₂Environment detection down for diluent gas has good low light-off temperature and high-temperature stability equally, and the present invention detects the working condition tests result through Tianjin internal combustion engine inspection center of country:

The discharging composition	CO?	HC?	Nox?
				g/kw.h?	0.01?	0.24?	2.99?
Europe IV standard is sex-limited	4.0?	1.1?	3.5?

Therefore, the present invention has good purification and urges effect, and through behind the purifying and catalyzing of the present invention, the exhaust emissions of engine meets Europe IV discharge standard, has extensive market prospects.

The specific embodiment

Embodiment 1

(1) gets rare-earth oxide La ₂O ₃, CeO ₂Totally 8 restrain transition metal oxide ZrO ₂3 grams, alkaline earth oxide BaO, SrO be totally 0.5 gram, is that 68% nitrate is mixed with lanthanum nitrate, cerous nitrate solution, zirconium nitrate solution with 24 grams, 9 grams, 2 gram concentration respectively, barium nitrate, strontium nitrate solution, above-mentioned three kinds of solution merge and mix with the equivalent deionized water and obtain mixed solution, and mixed solution is the limit stirring in mixed process, the limit dropping ammonia, accent PH is 9-12, obtain precipitation, suction filtration gets filter cake;

(2) get 450 gram aluminium colloidal sols and 450 gram polyvinyl alcohol and 50 gram γ-Al ₂O ₃Mix, be made into the active oxidation aluminum slurry, add above-mentioned filter cake, in ball mill ball milling 24-56 hour, obtain the mixed slurry of uniform particle size;

(3) the siderochrome aluminum slice is prepared into metal beehive carrier according to a conventional method, on the surface of one liter of metal beehive carrier, above-mentioned mixed slurry in the coating, under 130-180 ℃ of condition dry 3-5 hour then, calcining 3-5 hour under 500-1000 ℃ of condition again;

(4) get 0.5 gram precious metals pt, and to be mixed with bullion content with watery hydrochloric acid be 20% chlorine palladium acid solution, the metal beehive carrier that calcining is good floods in chlorine palladium acid solution fully, then under the 130-180 ℃ of condition dry 3-5 hour, roasting 3-5 hour promptly under 500-1000 ℃ of condition.

Embodiment 2

(1) gets rare-earth oxide La ₂O ₃, Nd ₂O ₃Totally 20 restrain transition metal oxide ZrO ₂, CoO totally 10 the gram, alkaline earth oxide BaO, CaO be totally 5 grams, is that 68% nitrate is mixed with lanthanum nitrate, neodymium nitrate solution, zirconium nitrate, cobalt nitrate solution with 120 grams, 60 grams, 30 gram concentration respectively, barium nitrate, calcium nitrate solution, above-mentioned three kinds of solution merge and mix with the equivalent deionized water and obtain mixed solution, and mixed solution is the limit stirring in mixed process, the limit dropping ammonia, accent PH is 9-12, obtain precipitation, suction filtration gets filter cake;

(2) get 2450 gram aluminium colloidal sols and 2450 gram polyvinyl alcohol and 120 gram γ-Al ₂O ₃Mix, be made into the active oxidation aluminum slurry, add above-mentioned filter cake, in ball mill ball milling 24-56 hour, obtain the mixed slurry of uniform particle size;

(3) the siderochrome aluminum slice is prepared into metal beehive carrier according to a conventional method, on the surface of one liter of metal beehive carrier, above-mentioned mixed slurry in the coating, under 130-180 ℃ of condition dry 3-5 hour then, calcining 3-5 hour under 500-1000 ℃ of condition again;

(4) get 1.5 gram precious metals pts, Rh altogether, and to be mixed with bullion content with watery hydrochloric acid respectively be 20% chlorine palladium acid, rhodium chloride solution, the metal beehive carrier that calcining is good floods in chlorine palladium acid solution fully, then under the 130-180 ℃ of condition dry 3-5 hour, roasting 3-5 hour promptly under 500-1000 ℃ of condition.

Embodiment 3

(1) gets rare-earth oxide CeO ₂, Y ₂O ₃Totally 15 restrain transition metal oxide ZrO ₂, CuO totally 5 the gram, alkaline earth oxide SrO, MgO be totally 3 grams, is that 68% nitrate is mixed with cerous nitrate, yttrium nitrate solution, zirconium nitrate, copper nitrate solution with 70 grams, 20 grams, 15 gram concentration respectively, strontium nitrate, magnesium nitrate solution, above-mentioned three kinds of solution merge and mix with the equivalent deionized water and obtain mixed solution, and mixed solution is the limit stirring in mixed process, the limit dropping ammonia, accent PH is 9-12, obtain precipitation, suction filtration gets filter cake;

(2) get 1900 gram aluminium colloidal sols and 1900 gram polyvinyl alcohol and 100 gram γ-Al ₂O ₃Mix, be made into the active oxidation aluminum slurry, add above-mentioned filter cake, in ball mill ball milling 24-56 hour, obtain the mixed slurry of uniform particle size;

(3) the siderochrome aluminum slice is prepared into metal beehive carrier according to a conventional method, on the surface of one liter of metal beehive carrier, above-mentioned mixed slurry in the coating, under 130-180 ℃ of condition dry 3-5 hour then, calcining 3-5 hour under 500-1000 ℃ of condition again;

(4) get 1 gram precious metals pd, Rh altogether, and to be mixed with bullion content with watery hydrochloric acid respectively be 20% chloroplatinic acid, rhodium chloride solution, the metal beehive carrier that calcining is good floods in chlorine palladium acid solution fully, then under the 130-180 ℃ of condition dry 3-5 hour, roasting 3-5 hour promptly under 500-1000 ℃ of condition.

Above-mentioned three resulting the present invention of embodiment after testing, the result is as follows:

Following table be the present invention in normal condition and after through 1050 ℃, 24 hours senile experiment, the volumn concentration of CO is 1.35% in simulation gas, CH ₄Content is 0.25%, and Nox content is 0.2%, O ₂Content is 4.2%, CO ₂Content is 6%, N ₂Be the data that detect under the environment of diluent gas:

Claims (3)

1. tail gas purification catalyst for gas fuel engine is characterized in that containing in every liter of metal beehive carrier the component of following weight number: γ-Al ₂O ₃50-120g, rare-earth oxide 8-20g, transition metal oxide 1-10g, alkaline earth oxide 0.5-5g, noble metal 0.5-1.5g; Described metal beehive carrier is prepared from by the siderochrome aluminum slice, and described siderochrome aluminum slice contains the chemical composition of following percentage by weight, and wherein C is 0.015-0.001%, Si is 0.8-0.1%, and Mn is 0.8-0.1%, and Al is 9.0-2.0%, Cr is 31-10%, and La is 0.15-0.01%; Siderochrome aluminum slice thickness is 0.01-0.15mm, the smooth surface no concave-convex.

2. tail gas purification catalyst for gas fuel engine according to claim 1 is characterized in that rare-earth oxide is La ₂O ₃, CeO ₂, Y ₂O ₃, Nd ₂O ₃In two or more any combination, transition metal oxide is ZrO ₂, TiO ₂, one or more any combination among NiO, CoO, the CuO, alkaline earth oxide is one or more any combination among BaO, SrO, CaO, the MgO, noble metal is one or more any combination among Pt, Pd, the Rh.

3. the preparation method of a kind of tail gas purification catalyst for gas fuel engine as claimed in claim 1 is characterized in that it may further comprise the steps:

(1) gets the rare-earth oxide of above-mentioned formula ratio, transition metal oxide, alkaline earth oxide is mixed with three kinds of solution with 1 nitrate that is 65-70% than amount and the concentration of 3-6 respectively, three kinds of solution merges and mixes with the equivalent deionized water and obtains mixed solution, and mixed solution is the limit stirring in mixed process, the limit dropping ammonia, accent PH is 9-12, obtain precipitation, suction filtration gets filter cake;

(2) equal 1 with mixed solution than aluminium colloidal sol: 10-20 and mixed solution equal 1 than polyvinyl alcohol: the amount of 10-20, get the γ-Al of commercially available aluminium colloidal sol and polyvinyl alcohol and formula ratio ₂O ₃Mix, be made into the active oxidation aluminum slurry, the filter cake that step (1) is obtained adds, and in ball mill ball milling 24-56 hour, obtains the mixed slurry of uniform particle size;

(3) the siderochrome aluminum slice is prepared into metal beehive carrier according to a conventional method, on the surface of one liter of metal beehive carrier, above-mentioned mixed slurry in the coating, under 130-180 ℃ of condition dry 3-5 hour then, calcining 3-5 hour under 500-1000 ℃ of condition again;

(4) get formula ratio noble metal and watery hydrochloric acid and be mixed with the precious metal salt acid salt solution that bullion content is 20-50%, the metal beehive carrier that calcining is good floods in the precious metal salt hydrochlorate fully, then under the 130-180 ℃ of condition dry 3-5 hour, roasting 3-5 hour promptly under 500-1000 ℃ of condition.