IL46006A

IL46006A - Catalyst reducing the toxic contaminants of combustion engine exhaust gas and process for preparation thereof

Info

Publication number: IL46006A
Application number: IL46006A
Authority: IL
Original assignee: Hoechst Ag
Priority date: 1973-11-24
Filing date: 1974-11-06
Publication date: 1977-05-31
Also published as: FR2252487B1; DE2358664A1; RO63718A; BR7409806A; AT339868B; SE407157B; DK608574A; SE7414660L; CH603995A5; IT1023341B; JPS5084484A; FR2252487A1; PL96832B1; CS193039B2; GB1465986A; NL7415137A; BE822503A; CA1029360A; DD115048A5; IL46006A0

Description

THE H 1088 The present invention relates to a catalyst toxic contaminants of engine exhaust and to a process for making It is known German Patent the exhaust gas of combustion engines can be decontaminated with the use of catalysts containing copper manganese and nickel oxides as their active are deposited on a filler In anattempt to reduce the decrease of which occurs upon the passage of exhaust gas through the and in view of the high ratio of catalyst surface area to catalyst it has been proposed in German Patent Specifications 1 097 344 and 1 187 535 to deposit the above metal oxides on honey comb Copper manganese and nickel which are deposited considerably less active catalytically than an identical oxide combination which is deposited on a filler It is accordingly an object of the present invention to provide catalyst oxides of and nickel are applied on to a ceramic honey comb carrier so as to remain fully active To this the tion provides for an intermediary layer of aluminum oxide to be applied on to the honey comb carrier prior to impregnating it with the catalytically active It is more particularly possible for the intermediary layer of aluminum oxide to be used in a proportion within the range 5 and 15 based on the The process of the present invention for making the catalyst heating the honey comb carrier to temperatures within the range 300 and introducing the hot carrier into a concentrated solution of an aluminum salt of a volatile acid for a period within the range 15 and 60 blowing out the carrier and drying it at room temperature heating the dry carrier for a period within the range 1 and 4 hours to temperatures within the range 350 and and then calcining it for a period within the range 2 and 6 hours to temperatures within the range and with the resultant formation of an intermediary layer of aluminum oxide on the honey comb heating the carrier to temperatures within the range 300 and dipping the hot carrier in a hot concentrated aqueous solution of catalytically active nickel and manganese salts of volatile acids and allowing it to remain therein for a period within the range 5 and 60 blowing out the carrier and drying it a period within the range 1 4 hours temperatures within the range 350 and 4 and calcining it for a period within the range 5 and 20 hours at temperatures within the range 700 and Further preferred features of the process of present invention for the honey comb carrier having the intermediary er and the catalytically active ingredients thereon to be heated for a period within the range 1 and 3 hours to temperatures within the range 400 and in a slightly reducing for the honey comb carrier to be heated in a nitrogen mixture containing approximately 5 of for aluminum nitrate to be used as the aluminum for aluminum hydroxychloride to be used as the aluminum salt for nitrates to be used as the nickel and manganese and for the aqueous solution to contain Cu and Ni and Mn in a ratio by weight of For an identical molar ratio of identical catalytically active the catalyst of the present invention enables nitrogen especially carbon monoxide and to be converted more and the decrease of pressure to be kept at a lower than with the use of a filler The following Examples illustrate the Example 1 describes the preparation of a filler catalyst and Example 2 describes the preparation of a conventional honey comb Examples and 4 desribe the honey comb of the present In all of the following oxides of nickel and manganese were used as the catalytically active catalyst in a molar ratio of of The gas tested in each of the Examples consisted of 20 000 pprn of 250 pprn of 000 pprn of by volume of the balance being N EXAMPLE 1 Prior art Pellets 5 mm in diameter having a strength of 12 to 15 kg per pellet and a specific surface area of 2 m the method of Brunauer Emmet and were used as the The pellets were made by granulating a blend of a product of Martinswerke with mately 5 weight of bentonite A product of on a rotating and by drying and calcining the resulting spheroidal granules for hours at The pellets were heated to and impregnated over a period of minutes with a hot concentrated aqueous solution of nickel and manganese The solution in excess was the impregnated pellets were dried and heated within 3 hours from 200 to so as to effect decomposition of the The filler catalyst so was aged artificially by heating it for 17 hours to in air and activated by treatment at with a mixture of by volume of by volume of The filler catalyst was contacted for 10 hours at with the test then cooled and tested while flowing the test gas thereover at a spatial velocity of 24 000 liter of gas per liter of catalyst per The following conversion rates were EXAMPLE Prior art A honey comb carrier 24 mm in diameter and 77 mm which consisted substantially of cordierit MgO 5 was heated to impregnated with the catalytically active which were in the manner described in Example The honey comb catalyst so made was aged artificially by heating it for 17 hours to in and activated by treatment at with a mixture of 95 by volume of and 5 by volume of The honey catalyst so made contained 18 weight of metal oxide mixture on 82 weight of It was tested in the manner described in 1 and the following resu Its were Catalyst of A honey comb carrier 24 mm in diameter and 77 which consisted substantially of cordierit 2MgO 5si0 was heated to dipped in a hot 50 aqueous aluminum nitrate solution and allowed to remain therein for 30 After having been blown out and the honey comb carrier was heated over a period of 3 hours from 200 to to effect decomposition of the nitrate and maintained for hours at The honey comb carrier so treated was impregnated with the catalytically active aged and activated in the manner described in Example The resulting honey comb catalyst contained 17 weight of metal oxide mixture andSweight of aluminum oxide on 75 weight of It was tested in the manner described in Example 1 and the following results were EXAMPLE Catalyst of A honey comb carrier diameter and 77 mm which consisted substantially of aluminum oxide a product of Feldmuhle was heated to dipped in a hot A aqueous solution of hydroxychloride and allowed to remain therein for 30 minutes After having been blown and the honey comb carrier was heated within 3 hours to and calcined a further 5 hours at The catalyst so made was aged and activated in the manner described in Example It contained 18 weight of metal oxide mixture and 8 weight of aluminum oxide on 74 weight of It was tested in the manner described in Example 1 and the following results were After contact with the test gas at 0 After contact with the test gas at 600 C EXAMPLE Four honey comb catalysts prepared as described in Example were tested in a motor endurance test on a four cylinder engine placed in a test stand and provided an adjustable electronic fuel revolution counter and fluid friction Two each of which had two honey comb catalysts were positioned in the outlet of the Secondary air was supplied at a place the two The following results were obtained at a speed of rpm and Catalyst Sec air Exhaust gas corning from Exhaust gas downstrea bed of catalyst ppra NO Vol Hexane Hexane 660 260 2680 20 60 670 260 2640 91 80 680 260 2640 55 120 680 7 1 260 2640 800 680 260 2600 30 1000 I insufficientOCRQuality

Claims

WHAT WE CLAIM IS: Ψ

1. ) Catalyst reducing the toxic contaminants of exhaust gas of combustion engines, the catalyst, which consists essentially of a ceramic honey comb structure as carrier arid a mixture of copper, nickel and manganese oxides as catalytically active ingredients, having an intermediary layer of aluminum oxide applied to the honey comb carrier, the layer being applied thereonto prior to impregnating the carrier with the catalytically active ingredients,

2. ) A catalyst as claimed in claim 1 , containing the intermediary layer of aluminum oxide in a proportion within the range 5 and 15 weight %, based on the catalyst .

3. ) A process for making a catalyst as claimed in claim 1 or 2, which comprises: heating the honey comb carrier to temperatures within the range 300 and 400°C ; introducing the -hot carrier into a concentrated solution of an aluminum salt of a volatile acid for a period 'within the range 15 and 60 minutes; blowing- out the carrier and drying it at room temperature; heating the dry carrier for a period within the range 1 and 4 hours to temperatures within the range 350 and 450°C and then calcining it for a period within the range 2 and 6 hours to temperatures within the range 500 and 700°C with the resultant formation of an intermediary layer of aluminum oxide on the honey comb carrier; heating the carrier to temperatures within the range 300 and 400 C; dipping the hot carrier in a hot concentrated aqueous solution of ca talytically active copper, nickel and manganese salts of volatile acids and allowing it to remain therein for a period within the range 15 and 60 minutes; blowing out the carrier and drying it for a period within the range 1 and 4 hours at temperatures within the range 350 and 450°C ; and calcinin it for a period within the range 5 and 20 hours at temperatures within the range 700 and 1000°C.

4. ) A process as claimed in claim 3, wherein the honey comb carrier having the intermediary layer and the catalytically active ingredients deposited thereon is heated for a period within the range 1 and 3 hours to temperatures within the range 400 and 500°C, in a slightly reducing atmosphere*

5. ) A process as claimed in claim 4, wherein the honey comb carrier is heated in a hydrogen/nitrogen mixture containing approximately 5 % of hydrogen.

6. ) A process as claimed in any one of claims .3 to 5, wherei aluinium nitrate is used as the aluminum salt.

7. ) A process as claimed in any one of claims 3 to 5 , wherein aluminum hydroxychloride is used as the aluminum salt.

8. ) A process as claimed in any one .of claims 3 to 7,

9. ) A process as claimed in any. one of claims 3 to 8, wherein the aqueous solution contains Cu and i and Mn. in a ratio by weight of 1:1:1.

10. ) A catalyst as claimed in claim 1 or 2 substantially as described in Example 3 or .

11. A process for making a catalyst as claimed in any one of claims 3 to 9 conducted substantially as described in Example 3 or .

12. ) A catalyst whenever obtained by a process as claimed in any one of claims 3 to 9 ana 11. Regc!. A'.icrneys P.O. Box 33H6, TEL-AVIV, ISRAEL