Note: Descriptions are shown in the official language in which they were submitted.
~5;253S ``
A PROCESS FOR THE PREPARATION OF HYDROCAR~ONS
The invention relates to a process for the preparation
of a hydrocarbon mixture from a mixture monoxide and hydro-
gen having an H2/CO molar ratio of les~ than 1.0, with the
use of an Fe-containing bifunctional cataly~t or catalyat
combination pos~es3ing, in addition to activity for the
conversion of an H2/CO mixture into substantially hydro-
carbon~, activity for the conver~ion of an H20~CO mixture
into an H2/C02 mixture.
In an investigation into said process by the Applicant
it has been ~ound that if the process is carried out at
a certain high space velocity R, a certain high conversion
C can be obtained, but that the stability oP the bifuncti-
nal catalyst or catalyst combination i9 not entirely satis-
factory. On ~urther investigation into said process by the
Applicant it has been found that this drawback can be eli-
minated by contacting carbon monoxide and hydrogen present
in the reaction product, if desired together with other
components o~ the reaction product, in a second stage with
a cobalt- or ruthenium-containing monofunctional catalyst
having activity for the conversion of an H2/CO mixture
into substantially hydrocarbons, with the proviso that
if the feed ~or the 3econd stage has an H2/CO molar ratio
of less than 1.5, water is added to said feed and that in
the seoond stage use is made of a cobalt- or ruthenium
containing bifunctional catalyst or catalyst combination
having, in addition to activity for the conversion of an
H2/CO mixture into substantiall7 hydrocarbons, activity
for the conversion of an H20/CO mixture into an H2iCo2
mixture. Thi~ process not only ensure~ that by the use
of the above-mentioned high space velocity ~ (now based
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on the total cataly~t ~y~tem in th~ ~ir3t and ~econd
qtage) a high converqion can be obtained without ~tabi-
lity problems becoming manifest, but that the con~ersion
obtained moreover has a higher value than the above-men-
tioned conversion C..
The preqent patent application therefore relates
to a proceqs for the preparation of a hydrocarbon mix-
ture, in which a mixture of carbon monoxide and hydrogen
having an H2JC0 molar ratio of lesq than 1.0 i9 contac-
ted in a first qtage with an Fe-containing bifunctional
catalyst or catalyst combination as defined above and
in which carbon monoxide and hydrogen preqent in the
reaction product of the first qtage, if desired together
with other components of said reaction product, are con-
15 tacted in a second stage with a cobalt- or ruthenium-con- :
taining monofunctional catalyst a~ defined above, with
the provi~o that if the feed for the second stage has
an H2~C0 molar ratio of less than 1.5, water i~ added
to 3aid feed and that in the seaond ~tage uqe iq made
of a cobalt- or ruthenium-containing bifunctional cata-
lyst or catalyst combination as defined above.
In the process according to the invention the star-
ting material is an H2/C0 mixture having an H2/C0 molar
ratio of le~q than 1Ø Such H2/C0 mixtures can very
suitably be prepared by steam gasification of a carbon-
containing material. Examples of quch materials are
lignite, anthracite, coke, crude mineral oil and frac-
tion3 thereof as well as oi's produced from tarsand and
bituminous qhale. Steam gasification is preferably carried
30 out at a temperature of 900-1500C and a pressure of
10-100 bar. In the proce~s according to the invention
the qtarting H2/C0 mixture preferably has an H2/C0 molar
ratio of more than 0.25.
The Fe-containing bifunctional catalysts or cataly~t
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535
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combinations that are suitable for u~e in the firYt stage
of the proceYs according to the invention, should posse~3,
in addition to activity for the converqion o~ an H2~C0
mixture into qubstantially hydrooarbon~, activity for
the conversion of an H20/C0 mixture into an H2~C02
mixture. In the fir~t qtage of the proces~ use is pre-
ferably made of a bifunctional cataly~t prepared by im-
pregnation and containing iron on a carrier. Examples
of such catalyqtq are:
a) catalyqts containing 30-75 part~ by weight of iron
and 5-40 parts by weight of magneqium per 100 parts
by weight of alumina and prepared by impregnating
an alumina carrier with one or more aqueous ~olutions
of qaltq of iron and magnesium and ~ubsequently dry-
ing the composition, calcining it at a temperature of
700-1200C and reducing it. Special preference is
given to such catalyqts containing, in addition to
40-60 part~ by weight of iron and 7.5-30 parts by
weight of magnesium, 0.5-5 parts by weight o~ copper
as reduction promoter and 1-5 part-q by weight o~
potassium as qelectivity promoter per tO0 parts by
weight of alumina and calcined at 750-850C and
reduced at 250-350C.
b) cataly3ts containing 10-40 part~ by weight o~ iron
and 0.25-10 parts by weight of chromium per 100 parts
by weight of ~ilica and prepared by impregnating a
~ilica carrier with one or more aqueous solutions of
s~ltq of iron and of chromium ~ollowed by drying the
compo~ition, calcining it and reducing it at a tempe-
rature o~ 350-750C. Special preference is given to
quch catalysts containing, in addition to 20-35 parts
by weight of iron and 0.5-5 part~ by weight of chro-
mium, 1-5 parts by weight of potaqsium as selectivi-
ty promoter per 100 part~ by weight of qilica and
calcined at 350-700 C and reduced at 350-500C.
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53Si
The first stage of the proces~ according to the in-
vention can very suitably be carried out by passing the
feed in upward or downward direction through a vertically
arranged reactor containing a fixed or moving bed of the
Fe-containing bifunctional cataly:3t or catalyst combina-
tion. The first stage can, for example, be carried out in
fixed-bed operation, bunker-flow operation, ebullated-bed
operation or fluidized-bed operation. The ~ir~t stage of
the operation i9 preferably carried out under the ~ollow-
ing conditions: a temperature of 200-350C and in par-
ticular of 250-350C, a pressure of 10-70 bar and in par-
ticular of 20-50 bar and a space velocity of 500-5000 and
in particular of 500-2500 Nl of gas/l of catalyst~h.
In the process according to the invention carbon
monoxide and hydrogen pre~ent in the reaction product
of the ~irst stage are used as feed ~or the second stage.
In addition to carbon monoxide and hydrogen, the feed
for the qecond stage~ay contain other components oP the
reaction product of the ~irst stage. For example, it is
possible to use as feed for the second stage the C2
fraction or C4 fraction of the reaction product of the
first stage and even the entire reaction product of the
first stage. In the second stage of the procesq accor-
dins to the lnvention the aim is that the largest possi-
ble quantity Or the carbon monoxide present in the feedfor the second stage iq converted into substantially
hydrocarbons over a monofunctional cobalt- or ruthenium-
containing catalyst having activity for this reaction.
~o t~is end the H2/C0 molar ratio in the feed for the
second stage must be at least 1.5 and preferably
1.75-2.25. If an H2/C0 mixture with a high H2/C0 molar
ratio is used a~ reed for the first stage, it is possi-
ble in the proces~ according to the inYention to obtain
a reaction product from the first stage having an H2/C0
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~52S3S
molar ratio of at least 1.5~ which is suitable as such to be converted in the
second stage over said catalyst.
If in the process according to the invention a reaction product
having an H2/C0 molar ratio of less than 1.5 is obtained from the first stage,
water should be added to the feed for the second stage and a cobalt- or ruthenium-
containing bifunctional catalyst or catalyst combination should be used in the
second stage that has, in addition to activity for the conversion of an H2/C0
mixture into substantially hydrocarbons, activity for the conversion of an
H20/C0 mixture into an H2/C02 mixture.
If in the process according to the invention the feed for the
second stage has an H2/C0 molar ratio of less than 105, a bifunctional catalyst
combination consisting of two separate catalysts is preferably used in the
second stage, which catalysts will for convenience be indicated as catalysts
A and B. Catalyst A is the cobalt- or ruthenium-containing catalyst having
activity for the conversion of an H2/C0 mixture into substantially hydrocarbons
and catalyst B is the catalyst with activity for the conversion of an H20/C0
mixture into an H2/C02 mixtureO Both in the use of a monofunctional catalyst
and in the use of a bifunctional catalyst combination in the second stage of
the process according to the invention, as catalyst A preference is given to
a cobalt catalyst and in particular to a catalyst prepared by impregnation and
containing cobalt on a carrier. Very suitable for the present object are
catalysts containing 10-40 parts by weight of cobalt and 0.25-5 parts by weight
of zirconium, titanium or chromium per 100 parts by weight of silica and
prepared by impregnating a si~ica carrier with one or more aqueous solutions
of salts of cobalt and zirconium, titanium or chromium, followed by drying
the composition, calcining it at 350-700C and reducing it at 200-350C.
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Catalyqts containing copper and ZillC and in which the
Cu/Zn ato~ic ratio lies between 0.25 and 4.0 are espe-
cially eligible as catalyst~ 3. In the cobalt- or ruthe-
nlum-containing bifunctional catalyst combination~ the
catalysts A and B can be present as a physical mixture.
When the second stage of the proce~s i9 carried out with
the use of a fixed cataly~t bed, the bed is preferably
built up of two or more alternating layers of particle
of cataly~t B and catalyst A, re~pectively. In the pro-
ce~s according to the invention water can be added tothe feed for the second qtage and a bifunctional cata-
lyst combination can be used in the qecond stage both
in ca~es where the reaction product of the ~irst ~tage
haq an H2/C0 molar ratio of less than 1.5, and in cases
where the reaction product of the first qtage already
has an H2/C0 molar ratio of at leaqt 1.5, it being desi-
rable, however, that the ~eed which iq contacted with
catalyst A in the qecond qtage has a higher H2/C0 molar
ratio. I~ ln the process according to the invention an
embodiment i9 chosen in which water iq added to the feed
for the second qtage and a bifunctional catalyqt combi-
nation i~ uqed in the second qtage, the quantity of ~a-
ter required i3 mainly determined by the H2~C0 molar
ratio of the feed for the second stage, the activity
of the catalyst combination for the conversion of an
H20/C0 mixture into an H2~C02 mixture and the desirable
H2/C0 molar ratio of the product that i9 contacted with
catalyst A.
The second qtage of the process according to the
invention can very suitably be carried out by passing
the feed in upward or downward direction through a ver~
tically arranged reactor containing a fixed bed of the
monofunctional cataly~t or of the bifunctional catalyst
or catalyst combination. The second stage of the process
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~ 2535
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can also be carried out using a qu:3pension of the cata-
lyst or catalyst combination in a hydrocarbon oil.
The ~econd stage of the Drocess ia preferably car-
ried out under the followiing cond:Ltions: a temperature
of 125-350C, in particular of 175--275C and a pre3sure
of 1-150 bar, in particular of 5-100 bar.
The invention will now be illustrated with reference
to the following example.
EXAMPLE
The following catalysts were used during the inves-
tigation:
Catalyst 1
Co/Zr/SiO2 catalyst containing 25 parts by weight of
cobalt and 1.8 parts by weight of zirconium per 100 parts
15 by weight of silica and prepared by impregnating a silica
carrier with an aqueous solution cantaining a cobalt
and a zirconium salt, followed by drying the compositiqn,
calcining it at 500C and reducing it at 280C.
Catalyst 2
Fe/Mg~Cu/K/Al203 catalyst containing 50 parts by weight
of iron, 20 parts by weight Or magnesium, 2.5 parts by
weight of copper and 4 parts by weight of potassium per
100 parts by weight of alumina and prepared by impreg-
nating an alumina carrier with an aqueous solution con-
taining an iron, magnesium, copper and a potassium 3alt,
followed by drying the composition, calcining it at 800C
and reducing it at 325C.
Catalyst 3
Cu/Zn/Al203 catalyst with a Cu/Zn atomic ratio of 0.55.
Catalyst mixture I
Catalyst mixture I consisted of a layer of catalyst 3
and a layer of catalyst 1 in a volume ratio o~ 1 : 2.
The catalysts 1 and 2 and the catalyst mixture I were
tested for the preparation in one or two stages of a
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hydrocarbon mixture from an H2/C0 mixture. The test was
carried out in one or two reactors o~ 50 ml each containing
a fixed catalyst bed. Fi~e experiments ~ere carried out.
Experiments 1 and 3 were carried out in one stage; the other
experiments in two stages. In all experiments a temperature
of 280C was used in the first stage. In all experiments
that were carried out in two stages the temperature was
230C in the second stage. In all experiments the pressure
was 30 bar and the space velocity based on the total
catalyst system was 1000 ~l.l .h 1, In the experiments
2 and 5 the total reaction product from the first stage
was used as feed for the second stage. In experiment 4
the C4 fraction of the product from the first stage was
used as feed for the second stage. The results of the
experiments are stated in the Table.
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535
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N O O ~ I I I I Is\ O
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N N
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h ~q O O ~h h O ~ ~ ~ ~ ~ ~ ~h h~
O O ~ :~ ~ O O O O
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O c~ h h h h+~ ~ h h ~ h h
O q~ h h O O ~ ~il O OO O
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~1~1 N 06-1 U~ N O O N O
h R rl~1 0 h
h ~ ~O O h h~ O ~ ~ ~ h h a) h h
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Of the experiment3 3tated in the table only the
two-qtage experiments 2, 4 and 5 are in accordanoe with
the invention. The one-qtage experiments 1 and 3 fall
outside the 3cope of the invention. For comparison they
have been included in the patent application.
The advantages of the two-stage process according
to the invention in re3pect of conversion of the H2/CO
mixture and 3t~bility of the Fe-containing bifunctional
catalyst are evident on comparing the result~ of:
experiment 2 with that of experiment 1, and
experimentS4 and 5 with that of experiment 3.
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