Note: Descriptions are shown in the official language in which they were submitted.
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~I H 1117
S3~
. The presen-t invention relates to a process for
removing h~drocarbons from -the o~f-gas of in~ternal
combustion engines.
A process for removing hydrocarbons from the off-gas
~ of internal combustion engines has been described in
I German published Specificati.on "Offe~Ale$ungsschriPt"
¦ 2 157 624, wherein the o~f-gas is treated with oxygen-
¦ 10 containing gas at temperatures within -the range 100 and
¦ 700C in contact with a car-rier-supported ca-talyst
containing barlum aluminate as the carrier and oxides of
copper, manganese and nickel and, if desired, cobalt as
the catalytically active ingredien-ts.
This process is not fully satisfactory, however, in
using an oxidiæing atmosphere which does not promote the
decon-tamination of the off-gas of internal combustion
engines from nitrogen oxides oeing equally contained
therein. To ensure an effective ca-talytic removal of
ni-trogen oxldes from o.~-gas, i-t is necessary for -the
catalyst -to be contacted with a gas stream which has
~ reducing properties or is at least neutral (U.S.Paten-t
¦: 2 924 504)
The present invention now provides a process for
removlng hydrocarbons.from the off-gas of internal
combustion engines, under non-oxidizing conditions. The
process of -the present invention comprises more
particul~rly reacting the hydrocarbons with steam and/or
carbon dioxide a-t temperatures within the range 200 and
800~ in con~act with an inert carrier-supporte~ catalyst
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having catalytically ac-tive o:~lles of copper, manganese
and nickel applied to the carrier, and thereby transiorming
-the hydrocarbons to carboYl monoxide and hydrogen. ;~
Further PL e~erred ~eatures 3f the pl~esent process
provide:
a) for th~ hydrocarbons -to be reacted at temperatures
within the range 300 and 600C;
'~J~ for th~ of~-gas to be cont~cted -~tith the catalyst at
a spatial velocity within -the range 5000 and 200 000 l
per hour per l o~ catalyst;
c) for the catalyst carrier to have -the individual oxides
o~ copper, manganese and nickel applied thereto in a
ratio by weight within the ranse 0.1 and 1;
d) for the individual elements to be applied to the
carrier in a ratio by weight o~ 1:1:1,
e~ ~or the inert carrier to consist of alumina, splnel
t~ , or cordierite;
f) ~or the carri.er to be a honey~comb carrier;
g) for the ca~rier to consist o~ pellets having a diameter
~ 20 within the range 2 and 5 mm;
h) ~or the use of` a catalyst made by heating the carrier
to temperatures within the range ~00 and 400C;
impregnating the carrier by dipping it for a period
withirl the range 20 and 40 minutes in a hot aqueous
solution of copper, manganese and nickel nitrates;
; removing liquid adhering super~icially to the carrier
by shaking; drying the carrier so impregnated with -;
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the nitrates o~ the catalytically active elements
for a period within the range 1 and 2 hours at
temperatures wit~in the range 105 and 130~C;
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decompocia~ -t~i~ nitrates to oxides by gladually
heat.ing t}le carr:ie-r to -t~ pera-tures within the range
350 arld 4~0 C; calcining the carrier so co~r~red wi.th
. the o~ides lor a perlod ~ithin the range 5 and 15
ho~rs to temperat-lres w.i-thin -the range 700 and gooc;
and ac-tivating the carrier for a period ~,~itnin the
ran~e 1 and 3 hours at temperatures within the range
300 and 500C by means o a hydrog-n/nitrog~n-mixture;
i) for the use of a catalyst made by first dipping the
carrier for a period within the range 20 and 40
minu-tes in an aluminum salt solution and tn~n
impregnating it with the copper, .nanganese and nickel
nltrate solution; removing liquid adhering superficially
to the carrier by shaking; drying the carrier having
the aluminum salt applied thereto for a period withi~
the range 1 an~ 2 hours -to tempera~ures within -the
range 105 and 120C and gradually heating it -to
temperatures within the range 350 and 500C; and
calcining the carrier having aluminum o~ide applled
thereto for a period within the range 3 and 10 hours
... . . ...
at temperatures ~ithin -the range 500 and 800C;
j) for aluminum nitrate to be used as -the aluminum salt;
k) for alumin~m hydroxychloride to be used as the
aluminum salt;
l~ for the use of a catalyst made by ~irst dippin~ the `~
carrier for a period within the range 20 and 40
minutes in an aqueous suspension of finely divided
~ alumina and then impregnating it ~ith the copper,
; manganese and nickel nitrate solutlonj remo~ing liquid
adherinO~ super~icially to the carrier by shaking;
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drying the carrier having t.le alu.-nina applied thereto
for a period within the ran~e 1 and 2 hours at
tem~eratures within the range 105 and 120C; gradually
heating the carrier to tempera-tures w.ithin the range ~:
350 and 50GC and maintaining it within that ~.
remperature range for a period with~.n the range 3
. and 10 hours. .
The process o~ the present inven~icn, wher ein
advantage is taken of those reactions which occur between .
hydrocarbons and steam and/or carbon dioxi~e in contact .~ .
with mixed oxide catalysts of copper~ manganese and
nickel, enables hydrocarbons to be removed from off-gas ~:
being free or substantially free frorn oxygen. Resulting
carbon monoxide and hydrogen are delivered to an oxidation ~-.
catalyst placed downstream of the mixed oxide cat~lyst,
admixed wit'n a.r and burnt. Needless to say it is
.necessary for a do~mstream catalyst to be used to ensure
. the oxidatlon of carbon monoxide contained from the onset - - -
in the off-gas of internal combustion èngines. ..:
. The catalysts used in the process of the present
~inve.ntion also enable nitrogen oxides to be removed
catalytically from the off-gas of internal combustion .
engines, under reducing conditions... . . . -
~ . In each cf the following Examples~ a-gas containlng
::~ .O.1 % by volume of n-hexane, .
10 % by volume of H20, :
10 % by volume of C02, - . . .
2 % by volume of C0, - .
0.2 % by volume of 2~
0.3 % by volume of N0, . ... -
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the balance being N2
was reac-ted as described herein i.n contact Wit}l a
catalyst con~aining the catalytically active incredients
Cu:Mn:Ni in the atomlc ratio of 1:1:1. The gas was heated
in each particular case to the lest temperature and
contacted with the catalyst at a spatial velocity of
24 000 liter per hour per liter of catalystc The residual
con~entratlon of ~0 and n-hecane, res~ectively, in the
reacted gas was identiYied and the conversion in % of ~-
these two substances was calculated therefrom .
The temperatures referred to in the Examples are
those at which 50 and 90 %, respectively, of NO and n-
hexane, respectively, were found to have been converted
(U50 hex; UgO hex; U50 NO; UgO NO)
The gas composition indicated hereinàbove is 'ypical
; of an exhaust gas of an internal combustion engine, with
an appropriate ratio of fuel to air.
EXAMpLE 1: (Comparative Example)
.. . ..
Preparation of_catal~st
20~ A~ equimolar blend of copper, manganese and nickel
nitrabes was kneaded at 100C to give a viscous homogeneous
mass, which ~as dried for 1 hour at 110C. Following -this,
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the mass was heated to 400C to decompose the nitrates.
The resultin~ mass was pulverized and -triturated lJIith a
~ 1 % solution of meth71cellulose (TYLOS ~ to obtain
; ~ material suitable for treatment in an extruder. The
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; extruded strands were calcined for 15 hours at 800C and
finally ~ctivated for 2 hours at 450C with 5 % by volume
of hydrogen, in a hydrogen-nitrogen atmosphere.
Cata~st proPerties: Specific surface area (~ET):
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1 7 m2/g
vol~le of ~ores~ 0.3 cm~/~
Convi~y~-:Lo-rl U5G hex 7
U50 N0 3~0 C rJc~o N0 410 C
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EX~IPLE 2: (Comparative Example)
Pre~aration of catal~rst
~ = =
An equimoIar blend Gf co~per, m~ngane~e a-nd nicl~el
nitrates and an iden-tical quantity of ~-aluminum hy~roxide
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(particle size less th~ m) were kneaded under vacuum ``
hile water was added toobtainaviscous paste, which was
dried for 2 hours at 110C. The dry paste was heated to
400C to decompose the nitrates. The resulting mass ~ra~
pulverized aIld a sieve fraction thereof, consisting of
particles with a size of less -than 200 ~m, was made into
a paste with the use of a 1 % TYLOS~solution, and -the
paste was del vered to an extruder. The e~truded strands
ere heated to 1250C while the temperature was increased h; ' '
at a rate o~ 100C per hour, and maintained at that
20~ temperature for 15 hours. Following thii~, the catalyst t~as
activated fo~ 2 hours at 450C with 5 % by volume o~
hydrogen, i~ a hydrogen-nitrogen atmosphere.
Catalyst pro~erties: Specific surface area (BET): 1.0 m2/g
Volume of pores: O.Z9 cm3/g
ConVersl-n-- U50 hex 7
U ~2~ir U 7~;or
50 NO ' ~ ' `' 90 NO (~ v .
EXAMPLE 3: (Comparative~Example)
3~ SPERALITHER (a product of Pechiney-St.Gobain), i.e. .~
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loosely agC~regated carrier mate~rial was heated to ~50
dipped in Q hot consen-trated equinlolar aqueous solution
of ccpper, manganese and nickel rîitrates and allowed -to
remain therein for 30 mlnutes.Liquid which adhered
superficially to the loosely aggregated material was
removed by shaking~ ~he impregnated material was dried
for 1 hour at 110C and heated to 400C while increasing
the temperature at iniervals o~ 50C/hour. The-carrier
material so covered with the metal oxides was calcined
for 10 hours at 800C and the resulting catalyst was
finally activated for 90 minutes at 450C by means of
5 % by vol~e of hydrogen, in a hydrogen/nitrogen
atmosphereO
Catal st pro~erties: Specific surface area (BET): 10.0 m2/g
Volume of pores: 0.41 cm3/g
Conve s r- U50 hex 520 C UgO hex 700 C
- ~U50 N0 2~C U : 330C
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ExAr~PLE 4: (Invention)
Pre~aration of catal~st
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Honey comb material ~ased on aluminum oxide (a
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p~oduct o~ FeldmUhle AG, Plochingen) was heated to 350C,
dipped in a solution of aluminum hydroxychloride (170 g
Al203/kg solution) and allowed to remain therein for 40
minutes. Solution which ad~ered superficially to the honey
conlb material was removed therefrom by shaking, the
carrier was dried ~or 2 hours at 110C and~heated to
450~ hile increasing the temperature at intervals of
; i 50C per hour. Following this, the honey comb carrier was
calcined for 6 hours at 700C. It~ wèight w~s ~ound to
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have been increased by 7.~ %.
The honey comb carrier so treated was heated to 30VC 5
dipped in an equimolar hot concentra-ted aqueous solution
of copper~ manganese and nickel nitrates and allowe~ to
remain therein for 40 minutes Liquid contained ln the
passageways of the honey-comb oarrier was removed by
snaking and the impregnated carrier was dried for 1.5
hours a-t 115C. Following this, it was gradually heated to
400C, while increasing the temperature at intervals of
50C/hour, to decompose the nitra-tes. The honey comb
carrier so covered with the metal oxides was finally
calcined for 6 hours at 800C and ac~ivated for 2 hours
at 400C with 5 % by volume of hydrogen, in a hydrogen
nitrogen-atmosphere.
_talyst pro~verties: Content of copper, manganese and nickel
oxides: 13.5 weight %
Specific surface area (BET): 7.3 m2/g
Volume of pores: 0.17 cm3/g
ConverSin: U50 hex U 580C
~50 N0 : 215 C Ugo NO : 320 C
EXAMPLE 5: (Invention)
Preparation of catalys-t
; Honey comb material based on cordierite (Corning Glass,
New York) w~s heated to 400C, dipped in a 50 % aqueous
solution of Al2(0H)5Cl and allowed to remain therein for
30 minutes. Liquid which adhered superficially to the honey
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comb material was removed therefrom by shaking, the carrier
was dried for 1 hour at 120C, and heated to 500C while
increasing the temperatu!~e a~ intervals of 100C/~our,
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wh?r~y the aluminu?. hydro-~Yychlorid~ -was decompo~e~ to
alumin~lm oxi~e. Follcl.~ing this, the honey oomb material
was calcirled ~or 5 hours at 800C.
The honey comb material so treated was heated to
400C, dipped in an equimolar hot concentrated aqueous
solution of copper, manganese and nickel nitrates and
allowed to remain therein for 30 minutes. Liquid
contained in +he passaOe~rays of the 'noney comb carrier
w~s removed by shaking and the impregnated carrier was
dried for 1 hour at 130C. The nitrates were decomposed
by gradual heating to 450C, whlle increasing the
temperature at intervals of 60C/hour. The honey comb
carrier so covered with metal oxides was calcined for
10 hours at 750C and finally activated for 3 hours at
300C with 5 /0 by volu~e of hydrogen, in a hydrogen/
nitrogen-atmosphere.
Catalyst pro~ert_es: Content of copper, manganese and nickel
oxid~s: 17. 5 waight %
Specific surfac:e area (BET): 5.4 m2/g
Volume of pores: 0.22 cm3/g
- ConverSln: U50 hex 3 90 hex : 520~C
U50 N0 255 C UgO N0 : 370C
E~AMPLE 6 (Invention)
Prepara-tion of catalyst: ~ - - i
Honey comb material the same as that used in Example
5 was heated to 350C, dipped in an aqueous suspension of -~
finely dispersed alumina (6.9 g Al203/100 g suspension) ;~
and allowed to remain therein for 30 minutes. Suspenslon
; 30 which adhered superfieially to the honey com~b carr.ier was
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removed therefrom by shaking and the carrier was dried
f`or 1 . 5 h at 110C. The dry honey comb carrier was heated.:
to 400C, while the -temperature was :increased at interv~ils~: .
of 80C/h~ and main-tained a-t th2t temperature for 5 hours~
. The carrier was impregnated wi-th copper, manganese
and nickel oxides and the ca-talyst was activated i.n the :
manner described in Example 5. . .~:
,
Ca~al~st properties: Content of copper, manganese and nickel
. oxides: 18.4 weight % - : ;
10~ . Specific surface area (BET): 5.9 m2/g
Volume of pores: 0.21 cm3/g ..
ConverSi~n: Ur~o hex U90 hex : 570 C . -
U50 N0 : 230C U90 N0 : 280 C -
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E~AMPI.E 7: (Inven~tion)
~ Preparation of catalyst
: Honey comb material based on cordierite ~Amsricanl ; :
Lava, Tennessee) wa3 covered wi-th an alumina layer in the
manner described in Example 5. The cataIytically ac-tive
..
ingredients were applied to the carrier and -the cata].yst
~: was activated in the manner described in Example 5.
Catalyst proDertiss: Content of copper, manganese and nickel
oxides: 14.0 weight % :.
Spec~.~ic surface area (BET): 6.6 m2/g '.;
Volume of pores: 0.18 cm3/~
Con~ersion: U o h : 4~0C U90 h~ : 520C ;~
- 5 ex ~x -
50 N0 255 C U90 N0 3 ~ ;
,;~;.
~ EXAMPLE 8:~(Invention)
1 30
' Prep~ration of catal~st
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H~ney comb material the same as that used in Example
4 was heated to 400C, dipped in an aqueous solution of
aluminum nitra-te (68 g Al203/kg solution) and allowed to
remain therein for 20 minu-tes. Solutlon which adhered
superficially to -the honey comb ma-terial was removed
-there~rom by shaking, the carrier was dried ~or 2 hours
at 120C, then heated -to 500C, while the temperature was
' increased at intervals of 60C/h, and maintained at that -~'
temperature for 5 hours. The weight of the honey comb
material so treated was found to have increased by 10.8
weight %. ,'
The catalytically active ingredients were applied
to the carrier and the catalyst was activated in the "
manner described in Example 4. , ,
'~ Catalyst ~oper-ties: Content of copper, manganese and nickel
oxides: 23.0 weight % ,
Specific surface area (BET): 5.2 m2/g `,
Volume of pores: 0.17 cm3/g ''
ConverSin: U50 hex UgO hex : 580C
U50 N0 215 C UgO N0 3
;',~ ' EXAMPLE 9: (Invention)
Prepara-tion of cata~st ~ -
' ~ a-aluminum hydroxide was rapidly blended with 5
weight,% of ben-tonite, the blend was admixed with a 1 %
TYL05 ~ solution and the whole was made into pellets on
` a granulating plate. A frac-tion consis-ting of pellets
; having a diameter within the range 4 and 5 mm was heated
irst to 400C, while the temperature was increased at
~- 30 in-tervals of 50C/h, then to 1450C, while the temperature
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was increased a-t intervals of 100C/h, and maintained at
-- -that higher temperature for 17 hours. The pellets so
treated had a diameter of 2.5 mmand a s-trength of 5 kg/
pellet.
A-t a temperature o~ 350 C, the pellets were dipped
in a hot (90C) concentrated aqueous solution of an
equimolar blend of copper, manganese and nickel nitrates
and allowed to remain -therein for 30 minutes. Solution in
excess was poured off, the pelle-ts were heated to 400C,
10 ~ while the temperature was increased at lntervals of 100C/
h, to decompose the nitrates. Following this, the tempera-
ture was increased to 800C and maintained for 15 hours.
The impregnated pellets were finally activated for 2
~ - hours a-t 450C with 5 % by volume of hydrogen7 in a~
" hydrogen/nitrogen-atmosphere.
Catal~st properties: Specific surface area (BET): 5.3 m /g
Volume of pores: 0.31 cm3/g
Conversion: U50 hex 480 C UgO hex 610 C
50 MO : 275 C UgO I~O 390C
EXAMPLE 10- (Inventior~)
~ : . ...... ........ . .
'g~ Preparation of catalyst
199 parts o~ ~-aluminum hydroxide (99.7 weight %
Al(OH)3; 80 ~O particles with a size of less than 0,5 ~m;
specific surface area 7 m2/g) and 1 part of aluminum
oxide (99.5 weight % Al203; mean particle size: 0.6 ~m;
speciflc surface area: 8.5 m2/g) were intimately blended
by thorough agitation in an aqueous suspensior.. The
:;:,
suspension Was dried at 110C, the resulting pulverulent
mass was made into a pas~;e with a 1 % TYLOS ~ sol~tion
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and extruded into strand.s having a diameter of 5 mm. The
strands were out while moist to s-trand sections 5 mm
long, which were dried at 100C and -then hea-ted -to 400C
while increasing the temperature a-t intervals of 100C/h.
The temperature was finally increased to 1400C and the
strand sec-tions were maintained at that temperature for
17 hours, whereby their diameter was reduced to 3.2 mm.
The strand sections so treated had a strength of 2.3 kg
mm.
The catalytically active ingredients were applied
to the carrier and the catalyst was activated in the
manner described in Example 9.
Catalyst properties: Speci~ic surface area (BET): 4.8 m2/g
Volume o~ pores: 0.24 cm3/g ;-
Conversion: U50 hex 470C UgO hex 500 C
50 N0 : 220 CUgO N0 : 280C.
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