DE2428555A1 - METHOD FOR REMOVAL OF HYDROCARBONS - Google Patents

Description

KNAPSACK AKTIENGESELLSCHAFT

K 1117

Process for removing hydrocarbons

The present invention relates to a method for removing hydrocarbons from exhaust gases from internal combustion engines.

From DT-OS 2 157 624 a method for removing hydrocarbons from the exhaust gases of internal combustion engines, among other things, is known, whereby the exhaust gases are at temperatures of 100 to 700 ⁰ C in the presence of a supported catalyst, which is made of barium aluminate as a carrier and the oxides of copper, Manganese and nickel and optionally cobalt as active ingredients, treated with oxygen-containing gases.

The disadvantage here is that the oxidizing atmosphere also removes the gases from internal combustion engines containing nitrogen oxides hindered. An effective catalytic removal of nitrogen oxides from exhaust gases is namely only possible if the gas stream fed to the catalyst has reducing properties, at least but is neutral (U.S. Patent 2,924,504). '

It is therefore the object of the present invention to provide a method for the removal of hydrocarbons from exhaust gases from internal combustion engines, in which the removal the hydrocarbons takes place under non-oxidizing conditions. This is achieved according to the invention by that the hydrocarbons with steam and / or carbon dioxide at temperatures of 200 to 800 ° C in

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Presence of a catalyst, which is made of oxides of copper, Manganese and nickel as active ingredients on an inert Carrier consists of carbon monoxide, and converts hydrogen. Furthermore, the method according to the invention can also optionally be characterized in that

a) the hydrocarbons are reacted at temperatures from 300 to 600 ° C .;

b) the exhaust gas with a space velocity of 5000 to 200000 liters per hour and per liter of catalyst passes over the catalyst;

c) the oxides of copper, manganese and nickel in weight ratios of the individual elements to each other between 0,1 and 1 are applied to the carrier;

d) the individual elements in a weight ratio of 1: 1: 1 are applied;

e) the inert carrier made of aluminum oxide, spinel or cordierite consists;

f) the carrier is designed as a honeycomb body;

g) the carrier consists of pellets 2 to 5 mm in diameter;

h) to produce the catalyst, the support is ^{heated to 300 to 400 °} C., immersed in a hot, aqueous solution of the nitrates of copper, manganese and nickel and allowed to remain in it for 20 to 40 minutes; shaking off the liquid adhering to the surface of the support; that one dries the coated with the nitrates of the active ingredients carrier 1 to 2 hours at 105 to 130 ° C and then to decompose the

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■ - · _ 3 -

Nitrates slowly to 350 to 45O ⁰ C. and that 5 glows the occupied with the oxides carrier to 15 hours at 700 to 30O ⁰ C and finally 1 to 3 hours at ■ 300 to 500 ° C using a hydrogen-nitrogen mixture activated;

i) Before being impregnated with the nitrates of copper, manganese and nickel, the support is heated to 300 to 400 ° C., immersed in the solution of an aluminum salt and allowed to remain in it for 20 to 40 minutes; shaking off the liquid adhering to the surface of the support; that the covered with aluminum salt carrier "1 to 2 hours at 105 to 120 ⁰ C dried and then slowly to 350 to 500 ⁰ C., and that the used alumina-supported finally annealed 3 to 10 hours at 500 to 80O ⁰ C;

j) the aluminum salt used is aluminum nitrate;

k) the aluminum salt used is aluminum hydroxyl chloride;

1) -before it is impregnated with the nitrates of copper, manganese and nickel, the support is heated to 300 to 400 ° C, immersed in an aqueous slurry of finely divided aluminum oxide and allowed to remain in it for 20 to 40 minutes; shaking off the slurry adhering to the surface of the support; that one dries the alumina support coated with 1 to 2 hours at 105 to 120 ° C, then heated slowly to 350 to 500 ⁰ C and finally holding 3 to 10 hours at these temperatures.

The method according to the invention allows removal the hydrocarbons from oxygen-free or oxygen-poor exhaust gas using the mixed oxide catalysts of the

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Copper, manganese and nickel reactions between hydrocarbons with water vapor and / or carbon dioxide. Carbon monoxide and hydrogen, which are created can be burned on a downstream oxidation catalytic converter after the addition of air will. The downstream connection of an oxidation catalytic converter is necessary anyway, since the exhaust gases from internal combustion engines contain carbon monoxide from the outset.

The catalysts according to the invention are under reducing conditions also catalyzes the removal of nitrogen oxides from the exhaust gases of internal combustion engines.

In the following examples, one gas was used in each case

O ,1 Volume ? 6 n-hexane 10 Volume ? 6 H ₂ O 10 Volume .9 £ CO ₂ 2 Volume ? 6 CO 0 , 2 Volume ? δ o ₂ 0 , 3 Volume ? 4 NO Remainder N "

implemented by the method according to the invention, wherein a Catalyst was used which contained the active ingredients in an atomic ratio of Cu: Mn: Ni = 1: 1: 1. The gas was preheated to the respective measuring temperature and was at a space velocity of 24,000 liters per hour and per liter of catalyst passed over the catalyst. In the converted gas, the The residual levels of NO and η-hexane are determined analytically and the percentage conversion of the components is calculated from this.

The temperatures are listed at which half or 90 % of the component contained in the gas ^(U 50 Hex ' ^U 90 Hex ^{5 U} 50 NO ^{; U} 90 N0 ^} "Wetzt ^was \

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1 ir

A gas of the above composition can be used with the appropriate Adjustment of the fuel / air ratio as exhaust gas in a conventional internal combustion engine attack.

Example 1 '(comparative example)

Catalyst manufacture; An equimolar mixture of the nitrates of copper, manganese and nickel were kneaded at 100 ⁰ C to a tough homogeneous slurry, v / hich 1 hour at 110 ⁰ C dried v / urde. The nitrates were decomposed by heating to 400 ^° C. The resulting mass was pulverized and triturated with a 1% strength solution of methyl cellulose (Tylose ^) to form a pulp that could be driven by an extrusion press. The strand extrudate was annealed for 15 hours at 800 ⁰ C and finally in a hydrogen - activated for 2 hours at 45O ⁰ C atmosphere containing 5 volume% of hydrogen - nitrogen.

Catalyst properties: Specific surface (BET):

1.7 m ² / g 3

Pore volume: 0.3 cm / g

Conversions: U _{50 Ηβχ} : 700 ⁰ C

TT · " ⁵ I ^ n ⁰ P ¹ TT · ZtID ⁰ P

.50 NO · ^ ^{υ uu} 90 NO · ^Lilu ^

Example 2 (comparative example)

Catalyst production: An equimolar mixture of the nitrates of copper, manganese and nickel was kneaded with the same amount of α - aluminum hydroxide (particle size <1 μm) with the addition of water and thickened in vacuo to form a tough paste. The paste was dried at 110 ° C. for 2 hours. The nitrates were decomposed by heating to 400 ° C. The resulting mass was pulverized and the sieve fraction <200 μΐη after pasting with 1% Tylose ^ solution was extruded using an extruder. The S ^ trang-

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extrudate was heated at a temperature increase of 100 C / hour to 1250 ⁰ C and held for 15 hours at this temperature. Nitrogen - - Subsequently, the catalyst in a hydrogen atmosphere was 5 volume% of hydrogen Z hours at 450 ° C activated.

Catalyst properties: Specific surface (BET):

1.0 ni ² / g

■ χ

Pore volume: 0.3 cm / g

Conversions: ^U 50 Hex ^{: 700} ° ^c

NO ^{: 525} ° ^CU 90 NO ^{: 750} ° ^C

Example 3 (comparative example)

Catalyst Preparation: Speralithe v- ^ - Schuttgutträgermaterial (. Pechiney-Saint Gobain) was heated at 35O ⁰ C and immersed in a hot concentrated aqueous equimolar solution of the nitrates of copper, manganese and nickel, and left therein for 30 minutes. After shaking off the adhering to the surface B'lüssigkeit the impregnated bulk was heated for 1 hour at 110 C and then dried at a temperature rise of 50 ° C / hour to ⁰ C AOO. The one with the metal oxides

• Q

Covered carrier material was calcined at 800 ° C. for 10 hours. Finally, the catalyst was activated for 90 minutes at 450 ^° C. in a hydrogen-nitrogen atmosphere with 5 % by volume of hydrogen.

Catalyst properties: Specific surface (BET):

10.0 m ² / g

■ z

Pore volume: 0.41 cm / g

520 ⁰ CU _{90 Ηβχ} : 700 ⁰ C

^over 50 NO ^{: 245} ° ^CU 90 NO

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509881/0587

■ Example 4 (.according to the invention)

Kq ta 1 vs at ο rl: · c- r ρ tell υπ f ?: A hub body based on aluminum oxide (Feldmühle AG, Plochingen) was ^{heated to 30O 0} C, immersed in a solution of aluminum hydroxyl chloride (170 g Al ^ / kg solution) and Leave in for 40 minutes. After shaking off the surface adhering to the honeycomb body solution, the support was heated for 2 hours at 110 ⁰ C dried and then with a temperature rise of 50 ° C / hour to 450 ° C. Finally, the honeycomb body was annealed at 700 ° C. for 6 hours. After that, he showed a weight gain of 7.8%.

The honeycomb body prepared in this way was heated to 300 ° C. and immersed in an equimolar hot concentrated aqueous solution of the nitrates of copper, manganese and nickel and left in it for 40 minutes. Thereafter, the liquid in the channels of the honeycomb body was partitioned "and the impregnated honeycomb body .1.5 hours at 115 ⁰ C dried. By slowly heating up (50 ° C / hour) to 400 ° C, the nitrates were decomposed. The one with the metal oxides finished honeycomb was calcined for 6 hours at 800 ⁰ C and finally two hours enabled bei.400 ⁰ C in a hydrogen-nitrogen atmosphere (5Vqlumen% hydrogen).

Catalyst properties; Content of oxides of copper, manganese and nickel: 13.5% by weight ■.

Specific surface area (BET): 7,3.m ² / g

■ z

Pore volume: 0.17 cm / g

Conversions: U _{50 Ηθχ} : 440 ⁰ CU _{90 Hex} : 580 ⁰ C ^U 50 NO ^{: 215} ° ^CU 90 NO ^{: 320} ° ^C

Example 5 (according to the invention)

Catalyst production: A cordierite-based honeycomb body (Corning Glass, New York) was heated to 400 ° C,

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immersed in a 50% aqueous solution of Al ₂ (OH) ^ Cl and left in it for 30 minutes. After the liquid adhering to the surface of the honeycomb body had been shaken off, the carrier was ^{dried at 120 °} C. for 1 hour. The dried honeycomb body was heated with a temperature increase of 100 ° C./hour to 500 ° C., the aluminum hydroxyl chloride being decomposed to aluminum oxide. The honeycomb body was then annealed at 800 ° C. for 5 hours.

The thus prepared honeycomb structure was heated to 400 ⁰ C and immersed in an equimolar hot concentrated aqueous solution of the nitrates of copper, manganese and nickel and held therein for 30 minutes. The liquid in the channels of the honeycomb was then shaken out and the impregnated honeycomb was dried at 130 ° C. for 1 hour. The nitrates were decomposed by slowly heating up (60 C / hour) to 450 ° C. The space occupied with the metal oxides honeycomb body was annealed for 10 hours at 750 ⁰ C and finally 3 hours at 300 ⁰ C in an activated hydrogen-nitrogen atmosphere (5Volumen% hydrogen).

Catalyst properties; Content of oxides of copper,

Manganese and Nickel: 17.5 weight ^. Specific surface area (BET): 5.4 m ² / g Pore volume: 0.22 cm / g

Conversions: U _{50 Hex} : 430 ° C _{U 90 Hex} : 520 ^{0 C}

Γ TT 77 (1 P

'50 NO * -'- ' ^{ϋ U} 9O NO * ^' ^{υ υ}

Example 6 (according to the invention)

KataJysatorhersteilung: A honeycomb body as used in Example 5 was heated to 350 ⁰ C, (/ 100 g suspension 6.9 g of Al ₂ 0 · *) immersed in an aqueous suspension of finely divided alumina and left therein for 30 minutes.

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After the suspension adhering to the surface of the honeycomb body had been shaken off, the carrier was ^{dried at 110 °} C. for 1.5 hours. The dried honeycomb body was heated with a temperature increase of 80 ° C./hour to 400 ° C. and kept at this temperature for 5 hours.

The impregnation with the oxides of copper, manganese and nickel and the activation took place as described in Example 3 .

Catalyst properties; Content of oxides of copper,

Manganese and Nickel: 18.4 weight ^

■. · Specific surface area (BET): 5.9 m ² / g. ■ Pore volume: 0.21 cm / g

Conversions: U _{50 Ηβχ} : 405 ° CU _{90 Ηβχ} : 57O ⁰ C ^U 50 NO ^{: 230} ° ^CU 90 NO ^:

Example 7 (according to the invention)

Catalyst production: A cordierite-based honeycomb body (American Lava, Tennessee) was provided with an aluminum oxide layer as described in Example 5. Likewise, the application of the active ingredients and. the activation according to Example 5 carried out.

Catalyst properties: content of oxides of copper,

Manganese and nickel: 14.0 weight ^ specific surface area (BET): 6.6 m ² / g pore volume: 0.18 cm / g

^U 50 Hex ^{: 430} ° ^CU 90 Hex ^{: 520} ° ^{C U} 50 W '' ²⁵⁵ ° ^CU 90 NO ^{: 370} ° ^C

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- ίο -

Example 8 (according to the invention)

Catalyst production: A honeycomb body used as in Example 4 was heated to 400 ° C., immersed in an aqueous solution of aluminum nitrate (68 g Al-O ^ / kg solution) and left therein for 20 minutes. After shaking off the solution adhering to the surface of the honeycomb body, the carrier was dried for 2 hours at 120 ° C. and then ^{heated to 500 °} C. with a temperature increase of 60 ° C./hour and held at this temperature for 5 hours. Thereafter, the honeycomb body showed a weight increase of 10.8 % . ■

The active components were applied and activated to the honeycomb body prepared in this way according to example 4. ·

Catalyst properties: content of oxides of copper,

Manganese and nickel: 23.0% by weight

Specific surface (BET):

5.2 m ² / g

Pore volume: 0.17 cm / g

Conversions: U _{50 Hex} : 440 ⁰ CU _{90 Ηθχ} : 580 ⁰ C ^U 50 NO ^{: 215} ° ^{C. U} 90 NO ^{: 320} ° ^C

Example 9 (according to the invention)

Catalyst production: α - aluminum hydroxide was mixed with 5 weight ^ bentonite and after adding 1% Tylose ^ - '- solution rolled into pellets on a granulating plate. The fraction of 4 to 5 mm in diameter was heated at a temperature rise of 50 C / hour to 400 ⁰ C and then brought to a temperature of 145 ° ° C with 100 ° C / hour and held there for 17 hours. The pellets now had a diameter of

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2.5 mm and a strength of 5 kg / pellet.

The pellets were placed at a temperature of 350 ° C. in a 90 ° C. concentrated aqueous solution of an equimolar mixture of the nitrates of copper, manganese and nickel, in which they remained for 30 minutes. After decanting the excess solution, the pellets were heated l.ur decomposition of the nitrates at a temperature increase of 100 ° C / hour to 400 ⁰ C, before the temperature for 15 hours at 800 ⁰ C was increased. Finally, the impregnated pellets were activated in a hydrogen-nitrogen atmosphere (5% by volume hydrogen) at 450 ° C. for 2 hours.

Catalyst properties: Specific surface (BET):

5.3 m / g

Pore volume: 0.31 cm / g

Conversions: U _{50 Rex} : 480 ⁰ CU _{90 Rex} : 610 ⁰ C " ^U 50 NO ^{; 275} ° ^CU 90 NO ^{: 39O} ° ^C

Example 10 (according to the invention)

Catalyst production: 199 parts of α - aluminum hydroxide (99.7% by weight Al (OH) _x ; 80 % <0.5 μπϊ; specific surface area:

2
7 m / g) and 1 part of α-aluminum oxide (99.5% by weight Al ₀ O ^; mean grain size: 0.6 μm; specific surface area: 8.5 m / g) were intimately mixed in an aqueous slurry by vigorous stirring. After drying the slurry at 110 C, the powdery 'mass was with. 1% Tylose ^ solution made into a paste and extruded through an extruder to form strands with a diameter of 5 mm. The strands were comminuted in the moist state into sections 5 mm in length. The sections were heated after drying at 100 C with a temperature increase of 100 C / hour to 400 ⁰ C. Eventually the temperature got up

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Increased 14OO ° C and the strand sections were 17 hours held at this temperature. The sections which had now shrunk to a diameter of 3.2 mm showed a strength of 2.3 kg / mm.

The application of the active ingredients to this carrier material and activation was carried out as indicated in Example 9.

Catalyst properties: Specific surface (BET):

4.8 m ² / g pore volume: 0.24 cm / g

Conversions: U _{50 Ηβχ} : 470 ⁰ CU _{90 Rex} : 500 ° C ^U 50 NO ^{: 220} ° ^CU 90 NO ^{: 280} ° ^C

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Claims (13)

- 13 - Claims: 1) Process for removing hydrocarbons from exhaust gases from internal combustion engines, characterized in that the hydrocarbons are mixed with water vapor and / or carbon dioxide at temperatures of 200 to 800 ⁰ C in the presence of a catalyst which consists of oxides of copper, manganese and nickel as active components insists on an inert carrier, to carbon monoxide, and converts hydrogen. 2) Process according to claim 1, characterized in that the hydrocarbons are reacted at temperatures of 300 to 600 ° C. 3) Method according to claim 1 or 2, characterized in that the exhaust gas is passed over the catalyst at a space velocity of 5000 to 200,000 liters per hour and per liter of catalyst. ■ 4) Method according to one of claims 1 to 3, characterized in that the oxides of copper, manganese and nickel are applied to the carrier in weight ratios of the individual elements between 0.1 and 1. 5) Method according to claim 4, characterized in that the individual elements are applied in a weight ratio of 1: 1: 1. 6) Method according to one of claims 1 to 5, characterized in that the inert carrier consists of aluminum oxide, spinel and cordierite. 7) Method according to one of claims 1 to 6, characterized in that the carrier is designed as a honeycomb body. - 14-509881 / 058 7 8) Method according to one of claims 1 to 7, characterized in that the carrier consists of pellets of 2 to 5 mm in diameter. 9) Process according to one of claims 1 to 8, characterized in that the carrier is heated to 300 to 400 ° C for the preparation of the catalyst, immersed in a hot, aqueous solution of the nitrates of copper, manganese and nickel and 20 to 40 minutes lets linger in it; shaking off the liquid adhering to the surface of the support; that the carrier covered with the nitrates of the active constituents is ^{dried for 1 to 2 hours at 105 to 130 °} C. and then slowly ^{heated to 350 to 450 °} C. to decompose the nitrates and that the carrier covered with the oxides is added for 5 to 15 hours 700 to 900 ⁰ C anneals and closes "Borrowed 1 to 3 hours at 300 to 500 ⁰ C with the help of a hydrogen-nitrogen mixture activated. 10) Method according to claim 9, characterized in that the carrier is heated to 300 to 400 ° C before its impregnation with the nitrates of copper, manganese and nickel, immersed in the solution of an aluminum salt and allowed to linger in it for 20 to 40 minutes; shaking off the liquid adhering to the surface of the support; that the support coated with aluminum salt is dried for 1 to 2 hours at 105 to 120 ° C. and then slowly ^{heated to 350 to 500 °} C. and that the support coated with aluminum oxide is finally ^{annealed at 500 to 800 °} C. for 3 to 10 hours. 11) Method according to claim 10, characterized in that aluminum nitrate is used as the aluminum salt. 12) Method according to claim 10, characterized in that there is used as aluminum salt aluminum hydroxyl chloride. - 15 509 881/0587 13) Method according to claim 9, characterized in that the carrier is ^{heated to 300 to 40O 0} C before its impregnation with the nitrates of copper, manganese and nickel, immersed in an aqueous slurry of finely divided aluminum oxide and dwell in it for 20 to 40 minutes leaves; shaking off the slurry adhering to the surface of the support; that the support covered with aluminum oxide is ^{dried for 1 to 2 hours at 105 to 120 °} C., then slowly heated to 350 to 500 ° C. and finally held at these temperatures for 3 to 10 hours. 509881/0587