Note: Descriptions are shown in the official language in which they were submitted.
lZ6~
A PROCESS FOR THE PREPARATION 0~ OXYGEN-CONTAINING
ORGAWIC COMPOUNDS AN~ PARAFFINI(' HYDROCARBONS
The invention relates to a process for the
preparation of oxygen-containing organic compounds and
paraffinic hydrocarbons from a mixture of carbon
monoxide and hydrogen.
Oxygen containing organic compounds such as
methanol, ethanol and dimethyl ether are valuable
end products, ar,~d intermediate products, for instance
for the preparation of aromatic hydrocarbons and
lower olefins. The said oxygen-containing organic
compounds can be prepared by catalytic conversion of
mixtures of carbon monoxide and hydrogen with an
H2/CO molar ratio of at least 0.5. A drawback of
these reactions is that they are thermodynamically
strongly limited, so that a considerable part of the
H2/CO mixture is not converted. According as higher
space velocities are used in the processes, lower
conversions are obtained. It is true that a higher
conversion can be reached by recycling the unconverted
H2/CO mixture, but recycling on a technical scale is
an expensi~e process, which should be avoided if at all
possible. Moreover, recycling the unconverted H2/CO
mixture entails another serious drawback. As a rule,
the reaction product contains in addition to o~ygen-
g
--2--
containing organic compounds formed and unconvertedhydrogen and carbon monoxide a considerable amount of
carbon dioxide. This carbon dioxide has formed by the
reaction of water with carbon monoxide according to
the known C0-shift reaction. The water required for
the C0-shift reaction may originate from an external
source or may have been formed in the preparation of
the oxygen-containing organic compounds. Addition of
water to the H2/C0 mixture in order to make the
C0-shift reaction proceed is carried out if the
available H2/C0 mixture has too low an H2/C0
molar ratio. According to the C0-shift reaction
the C0 content falls and the H2 content rises,
resulting in an increase of the H2/C0 molar ratio.
The C0-shift reaction can be carried out as an external
shift (also designated pre-shift), in which the H2/C0
mixture to be converted, together with added water, is
first conducted over a separate C0-shift catalyst,
before being contacted with the catalyst which has
activity for the conversion of an H2/C0 mixture into
oxygen-containing organic compounds. As the latter
catalysts generally have C0-shift activity as well, an
external shift can be omitted in a number of cases and
the desired increase of the H2/C0 molar ratio of the
feed can be achieved simply by conducting this feed
together with added water over the catalyst which has
activity for the conversion of an H2/C0 mixture
--3--
into oxygen-containing organic compounds. It i9 also
the C0-shift activity of the latter catalyst which
is responsible for the formation of carbon dioxide,
if water is formed in the preparation of the oxygen-
containing orgarlic compounds. This situation presentsitself if ether is formed in the preparation of oxygen-
containing organic compounds. To avoid the building up
of carbon dioxide in the process, the carbon dioxide
should be removed from the recycle stream. Removal of
carbon dioxide ~rom recycle streams on a technical
scale is, ~ust as the recycling itself, an expen-
sive process.
The applicant has carried out an investigation to
find out to what extent it is possible in the prepara-
tion of oxygen-containing organic compounds to realize
by catalytic conversion of an H2/C0 mixture a high
conversion of the H2/C0 mixture into valuable organic
compounds, without the necessity of recycling the
unconverted H2/C0 mixture and removing the carbon
dioxide. This possibilil;y was indead found to exist. To
this end carbon monoxide and hydrogen present in the
reaction product obtained in the catalytic conversion
of the H2/C0 mixture into oxygen-containing organi.c
compounds, if desired together with other components of
this reaction product, should be contacted with a
monofunctional catalyst containing one or more metal
components with catalytic activity for the conversion
t).L~
of an H2/C0 mixture into paraffinic hydrocarbons,
which metal components have been chosen from the group
formed by cobalt, nickel and ruthenium. If the H2/C0
mixture that is available as the feed for the preparation
of the paraffinic hydrocarbons has an H2/C0 molar
ratio lower than 1.5, water should be added to this
feed in an amount sufficient to bring by reaction
with C0 the H2/C0 molar ratio at a value of at least
1.5, and use should be made of a bifunctional catalyst
combination which, in addition to containing tha metal
components with catalytic activity for the conversion
of an H2/C0 mixture into paraffinic hydrocarbons~
also contains one or more metal components with C0-shift
activity. If the conversion of the H2/C0 mixture is
carried out in this way, it is possible, using a high
space velocity, to reach a very high conversion of the
H2/C0 mixture into oxygen-containing organic compounds
and paraffi~ic hydrocarbons. The paraffinic hydrocarbons
obtained in the process are valuable as end product and
as starting material for carrying out catalytic hydro-
carbon conversion processes ~such as aromatization,
isomerization, crackinK and hydro-cracking.
The present patent application therefore relates
to a process for the preparation of oxygen-containing
organic compounds and paraffinic hydrocarbons, in which
process a mixture of carbon monoxide and hydrogen with
an H2/C0 molar ratio of at least 0.5 is contacted in
o~
--5--
a first step with a catalyst containing one or more
metal components with catalytic activity for the
conversion of an H2/C0 mixture into oxygen-containing
organic compounds and in which process carbon monoxide
and hydrogen present in the reaction product from the
first step, if clesired together with other components
of this reaction product, are contacted in a second
step with a monofunctional catalyst as defined above,
on the understanding that if the feed for the second
step has an H2/C0 molar ratio lower than 1.5, water
is added to this feed in an amount sufficient to bring,
by reaction with C0, the H2/C0 molar ratio at a value
of at least 1.5, and that in the second step use is
made of a bifunctional catalyst combination as de~ined
above.
The process according to the invention is highly
flexible as regards the ratio of the amounts of oxygen-
containing organic compounds to paraffinic hydrocarbons
which can be prepared. If it is intended to effect the
highest possible yield o~ oxygen-containing organic
compounds, the circumstances under which the first step
of the process is carried out can be chosen such that
this wish is satisfied, and the unconverted H2/C0
mixture can be converted in the second step into
paraffinic hydrocarbons. If it is intended to effect a
high yield of paraffinic hydrocarbons, the circumstances
under which the first step of the process is carried
--6--
out can be chosen such that the reaction product of the
first skep contains a sufficient amount of unconverted
H2/C0 mixture to guarantee in the second step the
desired high yield of paraffinic hydrocarbons.
In the process according to the invention use is
made of an H2/C0 mixture with an H2/C0 molar ratio
of at least 0.5 as the feed for the first step. Such
H2/C0 mixtures can very suitably be prepared by steam
gasification of a carbon-containing material such as
coal. The steam gasification is preferab]y carried out
at a temperature of 900-1500C and a pressure of
10-100 bar. Preferred H2/C0 mixtures are those with
an H2/C0 molar ratio of 0.75-2.5. If the H2/C0
mixture that is available as the feed for the first
step has an H2/C0 molar ratio lower than 0.5, water
should be added to the H2/C0 mixture in an amount
sufficient to bring, by reaction with C0, the H2/C0
molar ratio at a value of at least 0.5, and the mixture
should be contacted with a catalyst having C0-~hift
activity. Addin~, water to the H~/C0 mixture and
contacting the mixture with a catalyst having C0-shift
activity is also possible in those cases where the
H2/C0 mixture already has an H2/C0 molar ratio of
at least 0.5, but where it is desirable to use an
H2/C0 mixture with a higher H2/C0 molar ratio. The
increase of the H2/C0 molar ratio can be carried out
as a so-called external C0-shift, in which the water-
~6~0~3
containing H2/C0 mixture is contacted, in a separatestep previous to the first step of the process according
to the invention, with a separate catalyst with C0-shift
activity. As the catalysts used in khe first step of
the process according to the invention as a rule have,
in addition to t,heir activity for the conversion of an
H2/C0 mixture into oxygen-containing organic compounds,
C0-shift activity, the increase of the H2/C0 molar
ratio may also be carried out as an internal C0-shift,
in which process the water-containing H2/C0 mixture
is contacted directly with the catalyst in the first
step of the process according to the invention. If in
the process use is made of an external C0-shift, it is
preferred not to apply carbon dioxide removal to the
reaction product. In the first step of the process
according to the invention an H2/C0 mixture which may
contain water and/or carbon dioxide, is contacted with
a catalyst containing one or more metal components with
catalytic activity for the conversion of an H2/C0
mixture into oxygen-containing organic compounds. It is
preferred to use in the first step a catalyst capable
of converting an H2/C0 mixture into substantially
methanol or dimethy~ ether. Examples of suitable
catalysts capable of converting an H2/C0 mixture into
substantially methanol are catalysts containing:
(a) zinc oxide and chromium oxide,
(b) copper, zinc oxide and chromium oxide,
~ 3
--8--
(c) copper, zinc oxide and aluminium oxide, and
(d) copper, zinc oxide and oxides of rare earths.
Examples of suitable catalysts having the capability
of converting an H2/C0 mixture into substantially
dimethyl ether are catalysts containing one of the
methanol synthesi.s functions under (a)-(d) and,in
addition, an acid function 9 such as a physical mixture
of gamma alumina and a composition containing copper,
zinc oxide and chromium oxide. The first step of the
process according to the invention is preferably
carried out at a temperature of 175-350C and a pressure
of 30-300 bar and in particular at a temperature o~
225-325C and a pressure of 50-150 bar.
In the process according to the invention carbon
monoxide and hydrogen present in the reaction product
from the first step, if desired together with other
components of this reaction product, are used as the
feed for the second step. If necessary, the complete
reaction product from the first step may be used as the
feed for the second step. In the second step of the
process accordin~ to the invention as much as possible
of the C0 present in the feed for the second step is to
be converted into paraffinic hydrocarbons over a
monofunctional catalyst containing one or more metal
components with catalytic activity for the conversion
of an H2/C0 mixture into paraffinic hydrocarbons,
which metal components have been chosen from the group
g ~ (3~3~
formed by cobalt, nickel and ruthenium. To this encd the
H2/C0 molar ratio ln the feed for the second step
should be at least 1.5 and preferably 1.75-2.25~ If use
is made of an H2~C0 mixture with a high H2/C0 molar
ratio as the feed for the first step, the first step of
the process according to the invention can yield a
reaction product in which an H2/C0 mixture is
present which has an H2/C0 molar ratio of at least
1.5 and which is as such suitable for conversion over
the said catalyst in the second step. An attractive way
of ensuring that in the process according to the
invention the reactiorl product from the first step has
an H2/C0 molar ratio of at least 1.5, is adding water
to the feed for the first step. Thanks to the C0-shift
activity of the catalyst in the first step this water
reacts with C0 from the feed to form an H2/C02
mixture. Adding water to the ~eecl for the first step
may be employed in the process according to the invention
both in cases in which, without water addition, a
reaction product would have been obtained from the
first step with an H2/C0 molar ratio lower than 1.5,
and in cases in which, also without water addition, a
reaction product would have been obtained already from
the first step with an H2/C0 molar ratio of at least
1.5, but where it is desirable that the feed contacted
with the catalyst in the second step should have a
higher H2/C0 molar ratio.
-1o ~26~ L9
If in the process according to the invention,
whether or not after water addition to the feed for the
first step, a reaction product is obtained from the
first step with an H2/C0 molar ratio lower than 1.5 9
water should be added to the feed for the second step
in an amount sufficient to bring, by reaction with C0
the H2/C0 molar ratio at a value of at least 1.5, and
in the second step use should be made of a bifunctional
catalyst combination which, in addition to the metal
components with catalytic activity for the conversion
of an H2/C0 mixture into paraffinic hydrocarbons,
also contains one or more metal components with C0-shift
activity. The bifunctional catalyst combinations that
may be used in the second step of the process according
to the invention are preferably composed of two
separate catalysts, which for convenience will be
designated catalyst A and catalyst B. Catalyst A is the
one containing the metal components with catalytic
activity for the conversion of an H2/C0 mixture into
20 paraf~inic hydrocarbons and which metal components have
been chosen from the group formed by cobalt, nickel and
ruthenium. Catalyst B is the one containing the metal
components with C0 shifk activity. Both if a mono-
functional catalyst is used and if a bifunctional
25 catalyst combination is used in the second step of the
process according to the invention, it is preferred to
use as catalyst A a cobalt catalyst such as a cobalt
60~
catalyst prepared by impregnation. Very suitable
for the present purpose are catalysts that contain
10-40 pbw cobalt and 0.25-5 pbw zirconium, titanium or
chromium per 100 pbw silica and which have been prepared
by impregnating a silica carrier with one or more
aqueous solutions of salts of cobalt and zirconium,
titanium or chromium, followed by drying the compositon,
calcining at 350-700C and reducing at 200-350C.
Suitable B-catalysts are the usual CO-shift catalysts.
In the bifunctional catalyst combinations the catalysts
A and B may be present as physical mixture. When the
second step of t;he process is carried out using a fixed
catalyst bed, this bed is preferably built up of two or
more alternating layers of particles of, successively,
catalyst B and catalyst A. Water addition to the feed
for the second step together with the use of a bi-
functional catalyst combination in the second step can
be used in the process according to the invention both
in cases in which the reaction product ~rom the first
step has an H2/CO molar ratio lower than 1.5, and in
cases in which the reaction product from the first step
already has an H2/C0 molar ratio of at least 1.5, but
where it is desired that the feed contacted in the
second step with catalyst A should have a higher
H2/C0 molar ratio. The second step of the process
according to the invention is preferably carried out at
a temperature of 125-300C and a pressure of 1-150 bar
~6~)0~
and in particular at a temperature of 175-275C and
a pressure of 5-100 bar.
The oxygen-containing organic compounds prepared
in the two-step process can very suitably be used as
starting material for the catalytic conversion into
lower olefins and/or aromatic hydrocarbons. This
conversion is preferably carried out by contacting the
oxygen-containing organic compounds at a temperature of
300-600C, a pressure of 1-50 bar and a space velocity
of 0.2-15 kg.kg-1.h-1 with a crystalline metal
silicate as the catalyst. It is preferred to use in
this conversion pressures of 1-10 bar.
Very suitable catalysts fcr the conversion of the
oxygen-containing organic compounds are crystalline
metal silicates characterized in that after one hour's
calcining in air at 500C they have the following
properties:
(a) thermally stable up to a temperature of at least
600C
(b) an X-ray po~der diffraction pattern showing
as the strongest lines the four lines given in
Table A.
~LZ6~0~
13-
Table A
d(~) Relative intensity
11.1 + 0.2 VS
10.0 + 0.2 VS
3.84 + 0.07 S
3.72 ~ 0.06 S
wherein the letters used have the following meanings:
VS = very strong; S = strong, and
(c) in the form~la w~ich represents the composition of
the silicate expressed in moles of the oxides, and
in which in addition to oxides of hydrogen, alkali
metal and silicon, one or more oxides of a trivalent
metal A chosen from the group formed by aluminium,
iron, gallium, rhodium, chromium and scandium are
present, the SiO2/A.203 molar ratio (further
designated m in this patent application) is more
than 10. These crystalline metal silicates will in
this patent application further be designated:
"silicates ~f type 1". The expression "thermally
stable up to a temperature of at least tC", as
used in this patent application, means that when
the silicate is heated up to a temperature of
tC, the X-ray powder diffraction pattern of the
silicate does not substantially change. The silicates
of type 1 can be prepared starting from an aqueous
~L~6~)0~9
mixture containing the following compounds: one or
more compounds of an alkali metal (M), one or more
compounds containing a quaternary organic cation
(R), one or more silicon compounds and one or more
compounds in which a trivalent metal A chosen from
the group formed by aluminium, iron, gallium,
rhodium, chromium and scandium is present. The
preparation of the silicates of type 1 is effected
by maintaining the mixture at elevated temperature
until the silicate has formed, separating it from
the mother l~quor and calcining it. In the aqueous
mixture from which the silicates of type 1 are
prepared the various compounds should be present in
the following ratios, expressed in moles of the
oxides:
M20 : SiO2 = 0.01 - 0-35 t
R20 : SiO2 - 0.01 - 0.4,
SiO2 : A203 > 10, and
H20 : SiO2 - 5 - 65.
~ariation oi~ the quaternary organic cation in-
corporated into the aqueous mixture yields silicates of
type 1 which differs at significant points as regards
their complete X-ray powder diffraction pattern.
The complex X ray powder diffraction pattern of an
iron silicate and of an aluminium silicate both prepared
using a tetrapropylammonium compound is given in Table B.
~L2~;~0~9
-15-
Table B
Relative Relative
d(R) intensity d(~) intensity
_
11.1 100 3.84 (D) 57
10.0 (D) 70 3.70 (D) 31
8.93 I 3.63 16
7.99 1 3.47 <1
7.42 2 3.43 5
6.68 7 3.34 2
6.35 11 3.30 5
5.97 17 3.25
5.70 7 3.05 `8
5.56 10 2.98 11
5.35 ~ 2.96 3
4.98(D) 6 2.86 2
4.60 4 2.73 2
4.35 5 2.60 2
4.25 7 2.48 3
4.07 2 2.40 2
4.00 4
(D) - doublet
~O~
-16-
The complete X-ray powder diffraction pattern of
an iron silicate and of an aluminium silicate prepared
using a tetrabutylammonium compound or a tetrabutylphos
phonium compound is given in Table C.
Table C
Relative Relative
d(~tensity d(~) intensity
11.1 100 3.84 65
10.0 70 3.70 20
7.42 2 3.63 <2
6.68 5 3.47 2
6.35 2 3.34
5.97 16 3.30 4
5.70 <1 3.05 5
5.56 8 2.98 9
4.98 6 2.86
4.60 3 2.60 2
4.35 5 2.~18 3
4.25 <1 2.40 . 2
4.00 <1
When silicates of type 1 are used as catalysts for
the conversion of the oxygen-containing organic compounds,
preference is given to silicates containing only one of
~ ~ 60 ~9
-17-
the above mentioned trivalent metals and in particular
to silicates containing as trivalent metal aluminium,
iron or gallium.
Other very suitable catalysts for the conversion
of the oxygen-corltaining organic compounds are the
following crystalline aluminosilicates: faujasite,
zeolite Y, zeolite X, mordenite, erionite, offretite,
zeolite ~, ferririte, chabasite and zeolite ZSM-34.
These crystalline aluminosilicates will in this patent
application further designated: "silicates of type 2".
Other very suitable catalysts for the conversion
of the oxygen-ccontaining organic compounds are silicates
of type 1 or type 2 upon which one or more catalytically
active metals have been deposited by impregnation or
ion exchange. These crystalline silicates will in this
patent application further be designated: "silicates of
type 3". Preference is given to silicates of type 3
upon which magnesium or manganese has been deposited.
If it is intended to convert the oxygen-containing
organic compounds into substantially aromatic hydrocar-
bons, the conversion is preferably carried out at a
temperature of 300-40noc and a space velocity of
0.5-5 kg.kg-1.h-1 and the preferred catalyst is a
silicate of type 1, whose m is less than 200.
If it is intended to convert the oxygen-containing
organic compounds into substantially lower olefins, the
conversion is preferably carried out either at a
.
~6~ L9
-18-
temperature of 400-6000C, a space velocity of
1-10 kg.kg-1.h-1 and using as the catalyst a
silicate of type 1, whose m is more than 200, or at a
temperature of 300~500C, a pressure of 1-5 bar, a
space velocity of 0.2-2 kg.kg-1.h-1 and using as
the catalyst a silicate of type 2 or type 3.
~ or the catalytic conversion of oxygen-containing
organic compounds into lower olefins and/or aromatic
hydrocarbons it is preferred to start from a feed of
dimethyl ether or a mixture of oxygen-containing
organic compounds consisting substantially of dimethyl
ether. In addition to C4- olefins and Cs~ hydro-
carbons, C4- paraffins are formed in the catalytic
conversion of oxygen-containing organic compounds. In
the conversion it is desirable to suppress the formation
of C4- paraffins as much as possible. An investi-
gation by the Applicant has shown that in the catalytic
conversion of the oxygen-containing organic co~pounds
the selectivity to C4- paraffins is lower if the
oxygen-containing organic compounds are not used
as such as the feed, but diluted. Suitable diluents
are, inter alia t water, carbon monoxide, carbon
dioxide, hydrogen and C4- paraffins.
The combination of the two-step process according
to tha invention with a process for the catalytic
conversion of oxygen-containing organic compounds into
lower olefins and/or aromatic hydrocarbons is very
~2~)0:19
-19-
attractive, because the reaction product from the flrst
step of the prooess according to the invention contains
at least a number of the above-mentioned diluents,
viz.: unconverted hydrogen and carbon monoxide and
further water and/or dioxide and/or C4- paraffins.
The combination of the two-step process according
to the invention with a process for the catalytic
conversion of oxygen-containing organic compounds into
lower olefins and/or aromatic hydrocarbons may be
0 carried in three ways.
Accord~ing to the first embodiment the reaction
product from the first step consisting of oxygen-
containing organic cornpounds, hydrogen, carbon monoxide
and a by-product containing carbon dioxide and/or water
and/or C4- paraffins is separated into at least two
fractions of which one contains all the oxygen-containing
organic compounds and at least 50%v of the by-product,
and one contains all of the hydrogen and carbon monoxide.
The latter fraction may contain the rest of the by-
20 product. The frackion containing the oxygen-containing
organic compounds is catalytically converted into lower
olefins and/or aromatic hydrocabons and the fraation
containing hydrogen and carbon monoxide is catalytically
converted in the ~reviously mentioned second step of
25 the process according to the invention. In this embodiment
the reaction product from the first step is separated
preferably into two fractions, of which one contains
20-
all the oxygen-containing organic compounds and all of
the by-product, and the other contains all of the
hydrogen and carbon monoxide.
According to the second embodiment, at least all
of the hydrogen, carbon monoxide and oxygen-containing
organic compounds of the reaction product from the
first step are together used as the feed for the second
step of the process according to the invention. By
preference, the complete reaction product from the
first step is used as the feed for the second step. The
reaction product of the second step, which consists
substantially of oxygen-containing organic compounds
formed in the first step and of paraffinic hydrocarbons
formed in the second step, and which contains in
addition, inter alia, unconverted hydrogen and carbon
monoxide, water and possible carbon dioxide, may be
used as such as the feed for the additional process
step in which catalytic conversion of the oxygen-contai-
ning organic compounds into lower olefins and/or
aromatic hydrocarbons takes place. In view of the
possibility that part of the Cs+ paraffinic hydro-
carbons formed in the second step is converted in the
additional process step into aromatic hydrocarbons,
which may be undesirable, it is preferred to separate
the Cs+ hydrocarbons from the reaction product of
the second step before using this reaction product as
the feed for the additional process step.
-21-
According to the third embodiment, at least all of
the hydrogen, carbon monoxide and oxygen-containing
organic compounds of the reaction product from the
first step are together contacted in the additional
process step with the catalyst converting the oxygen-
containing organic compounds into lower olefins and/or
aromatic hydrocarbons. By preference, the complete
reaction product from the first step is used as the
feed for the additional process step. Of the reaction
product from the additional process step, which contains
hydrogen, carbon monoxide, C4- olefins, a Cs~ fraction
rich in aromatics, C4- paraffins, water and pos-
sibly carbon dioxide originating from the first step,
at least hydrogen and carbon monoxide should be used as
the feed for the second step of the process according
to the invention. If desired, the complete reaction
product from the additional process step may be used as
the feed for the second step of the process according
to the invention. It is preferred to separate the
C4- olefins from the reaction product of the
additional process step before using this reaction
product as the feed for the second step of the process
according to the invention.
The Applicant has found that if in the second step
of the process use is made of the previously mentioned
cobalt-impregnation catalyst promoted with zirconium,
titaniurn or chromium, a mixture of heavy paraffinic
-22- ~26~9
hydrocarbons is obtained, which is pre-eminently
suitable for high-yield conversion into middle distillate
by hydrocracking. The hydrocracking operation is
characterized by a very ~ow gas production and hydrogen
5 consumption.
The invention will now be explained with reference
to the following example.
Example
In the investigation use was made of the following
10 catalysts.
Catalyst 1
_
A Cu/ZnO/Cr203 catalyst with a Cu/Zn/Cr
atomic ratio of 5:3:2.
Catalyst 2
_
~-Al203 calcined at 800C.
Catalyst 3
A Cu/ZnO/Al203 catalyst with a Cu/Zn atomic
ratio of 0.55.
3~)~9
-23-
Catalyst L~
A Co/Zr/SiO2 catalyst that contained 25 pbw
cobalt and 0.9 pbw zirconium per lO0 pbw silica and
which had been prepared by impregnating a silica
carrier with an aqueous solution containing a cobalt
and a zirconium salt, followed by drying the composition,
calcining it at 500C and reducing it at 250C.
Catalyst 5
_
A crystall:i.ne aluminium silicate which, after one
hour's calcining in air at 500C, had the following
properties:
(a) thermally stable up to a temperature of at least
800C,
(b) an X-ray powder diffraction pattern substantially
as shown in Table B, and
(c) in the formula representing the composition of the
silicate, expressed in moles of the oxides, the
SiO2/Al203 molar ratio was higher than 10.
Catalyst mlxture I
A physical mixture of catalyst 1 and catalyst 2
in a weight rat:io of l:1.
-2l~ 60~9
Catalyst mixture II
A layer of catalyst 3 and a layer of catalyst Ll
in a volume ratio of 1:2.
The catalysts 1 and 4 and the catalyst mixtures I
and II were tested for the preparation of methanol or
dimethyl ether in one step and for the preparation of
paraffinic hydrocarbons and methanol or dimethyl ether
in two steps. The test was carried out in one or two
50-ml reactors containing a fixed catalyst bed. Seven
experiments were carried out. The experiments 1, 2 and
4 were carried out in one step; the other experiments
were carried out in two steps. In all the experiments a
pressure of 60 bar was used in the first step. In all
the experirnents carried out in two steps the complete
reaction product from the first step was used as the
feed for the second step. The feed for the first step
of experiment 7 had been obtained from an H2/C0
starting mixture with an H2/C0 molar ratio of 0.5.
To this H2/C0 mixture so much water was added that
after performing an external C0-shift over catalyst 3
an H2/C0 molar ratio of 1.0 was reached. The C02
formed in the C0-shift (14.3 %v based on the gas
mixture) was not separated off. The C02-containing
H2/C0 mixture with an H2~C0 molar ratio of 1.0 was
used as the feed for the first step of experiment 7.
The results of the experiments 1-7 are listed in
Table D.
-25~ 00:~3
In experiment 8 a three-step process was simulated
for the converslon of an H2/C0 mixture into aromatic
hydrocarbons, lower olefins and paraffinic hydrocarbons,
using the composition of the product from the first
5 step of experiment 7 listed in Table D.
Experiment 8
The product f`rom the first step of experi~ent 7
can be separated into two fractions, viz. a fraction A
consisting of hydrogen and carbon monoxide with an
H2/C0 molar ratio of 0.88 and a fraction B consisting
of dimethyl ether, carbon dioxide and water in a volume
ratio of 24.1 : 70.5 : 5.4. In experiment 8 the two
fractions were converted separately.
Fraction A was conducted over catalyst mixture II
at a temperature of 240C, a pressure of 36 bar, a
space velocity of 1000 Nl.l-1.h~1 and with addition
of 0.171 water per l catalyst per hour. The conversion
of the H~/C0 mixture was 87 %v. When the conversion
o~ the H2/C0 mixture in the first step of experiment
7 is taken into account, this means a total conversion
of the H2/C0 mixture of 93 %v.
Fraction B was conducted over catalyst 5 at a
temperature of 500C, and a pressure of 1 bar and a
space velocity of 1 g dimethyl ether/g catalyst/h. The
conversion of dimethyl ether was 100~. The hydrocarbon
-26_ ~ 2 6 0 0~ 9
mixture formed had the following composition:
30 ~w of a C5-~ fraction rich in aromatics,
60 ~w of a C4- olefin fraction,
10 ~w of a Cl~~ paraffin fraction.
Of the experiments 1-8 described above, only the
two-step experiments 3 and 5-7 and the three-step
experiment 8 are experiments according to the invention.
The one-step experiments l, 2 and Ll are outside the
scope of the invention. They have been included in the
patent application for comparison.
The following remarks can be made with regard to
the results listed in Table D.
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-28- ~ 3
The experiments 1 and 2 show the one-step prepara-
tion of methanol. In experiment 1 a low conversion of
the H2/C0 mixture is reached (41 ~v). In comparison
with experiment 1 the space velocity in experiment 2
has been reduced by a factor of 4. The result of
experiment 2 shows that this causes an increase in the
conversion of the H2/C0 mixture (from 41 to 56 %v),
but the conversion achieved is still much too low for
using the process on a technical scale without recycling
the unconverted H2/C0 mixture.
Experiment 3 demonstrates the preparation of
methanol and paraffinic hydrocarbons using the two-step
process according to the invention.With use of the same
space velocity as in experiment 2 (now based on the
total catalyst volume in the first step and the second
step) a conversion of the H2/C0 mixture of 94 %v is
reached now.
Experiment 4 shows the one-step preparation of
dimethyl ether. In comparison with experiment 2 (one~step
preparation of methanol) the conversion of the H2/G0
mixture is higher now (66 instead of 56 %v), but the
conversion achieved is still far too low for using the
process on a technical scale without recycling the
unconverted H2/C0 mixture.
Experiments 5-7 show the preparation of dimethyl
ether and paraffinic hydrocarbons using the two-step
process according to the invention. In comparison with
-29~ 0 0~ ~
experiment 4, in experiment 5 a conversion of the
H2/CO mixture is reached of 93 %v, using the same
total amount of catalyst. Experiments 5 and 6 demonstrate
the two step process according to the invention,
starting from H2/CO mixtures with different H2/CO
molar ratios. In view of the low H2/CO molar ratio of
the product from the first step of experiment 5 (1.0),
water is added to the feed for the second step in this
experiment. Experiment 7 is a variant of experiment 5,
in which the H2/CO mixture with H2/CO molar ratio 1.0,
which is used as the feed for the first step, has
been obtained by applying an external CO-shift to an
H2/CO mixture with an H2/CO molar ratio of 0.5 and
in which the C02 formed is not removed. Just as in
experiment 5, in experiment 7 water is added to the
feed for the second step in view of the low H2/CO
molar ratio of the product from the first step (o.88).
