Note: Descriptions are shown in the official language in which they were submitted.
aye 37S
K 5966
PROCESS FOR THE PRODUCTION OF HYDROCARBONS
The invention relates to a process for the production of
hydrocarbons from synthesis gas, characterized in that the
synthesis gas is passed at elevated pressure and temperature
over a catalyst consisting of zirconium oxide promoted with at
least one alkaline earth metal cc~Found and/or at least one
Group III b metal cc~pound. The group III b metals of the
Periodic Table of Elements are defined in the "Handbook of
Chemistry and Physics", Thea edition (1962), page 448. The
catalyst may be supported on a suitable carrier such as alumina
or silica.
In the process according to the invention the starting
material is synthesis gas, i.e. a gaseous mixture consisting
substantially of Ho and CO. Such H2/CO mixtures can very
suitably be prepared by steam gasification or partial cc~bustion
of a carbon-containing material. Examples of such materials are
wood, peat, brawn coal, bituminous coal, anthracite, coke, crude
mineral oil and fractions thereof as well as tars and oils
extracted from tar sand and bitterns shale. The steam gasify-
cation or partial combustion is preferably carried out at a
temperature of 900-1600C and a pressure of 10-100 bar. In the
process according to the invention it is ac~van-tageolls to star-t
from an H2/CO mixture with an HO molar ratio of ore than
0.25 and less -than 6.
The intention is to convert the largest possible quantity
Of the CO present in the feed into hydrocarbons. To this end the
H2/CO molar ratio in the feed is suitably about 1Ø
The process according to thy invention can very suitably be
carried out by conducting the feed in upward or downward
375
direction through a vertically mounted reactor containing a
fixed bed of the catalyst or by passing the gaseous feeds
upwardly through a fluid catalyst bed. The process can also be
carried out using a suspension of the catalyst or catalyst
combination in a hydrocarbon oil. The process is preferably
carried out under the following conditions: a temperature in the
range from 200 to 600C and in particular from 300 to 500C, a
pressure in the range from 0.1 to 1000 bar and in particular
from 5 to 200 bar and a space velocity in the range from 100 to
lo 5000 No synthesis gas/l catalyst hour
In order to improve the hydrocarbon yield of the process
according to the invention a catalyst is applied having an
extensive specific surface area, preferably in the range from 20
to 500 mug Such a ZrO2 catalyst is prepared in the following
way: a zirconyl salt, e.g. a chloride or nitrate is solved in
water. While stirring ammonia is gradually added to the solution
until the pi of the solution is in the range from 7 to 10. The
precipitated zirconium hydroxide is separated from the solution
by filtration and washed. It is calcined during 1 to 24 hours in
air at a temperature in the range from 300 to 1000C.
By adding an alkaline earth metal compound and/or a Group
III b metal compound to the catalyst the selectivity for Kiwi-
drocarbons and especially the selectivity for iso-butene is
improved. Therefore, the process is carried out using a catalyst
promoted with an alkaline earth metal compound and/or a Group
III b metal compound, preferably a metal oxide.
In order to improve the activity and stability of the
catalyst it is advantageously calcined before being used,
suitably at a temperature in the range from 400 to 800C.
Although any alkaline earth metal compound may be used as
catalyst promoter in the present process, preference is given to
a calcium compound and/or barium compound because it is readily
available, cheap and it gives good results as to selectivity
improvement. Of the Group III b metals yttrium is particularly
preferred.
The promoter metal content of the catalyst is advantageous-
lye chosen between 0.05 and 50% by weight, and preferably button and 10~ by weight.
The invention will new be elucidated by means of the
following Examples.
Employ 1
A gaseous mixture of hydrogen and carbon monoxide having a
KIWI molar ratio of l was passed over a bed of zirconium
oxide catalyst particles containing 1% by weight of calcium in
the form of Coo and having a specific surface area of 97 mug
which was the result of a previous calcination step carried out
in air for 2 hours at 500C. The catalyst particles size was
from 0.4-0.6 mm.
The reaction conditions were chosen as follows:
Temperature : 450C
Pros Æ e : 20 bar as.
Gas hourly space velocity: 1000 Nl/l.h
me CO-conversion to hydrocarbons was 17%.
The hydrocarbon product had the following composition:
Hydrocarbons Paraffins Olefins
Of 45'1 _ _
C2 7.6 3.3 4.3
C3 4.3 2.2 2.1
iso-C4 24.7 9.2 15.5
n-C4 3.8 not determined not determine
C5 14.4 not determined not determine
pi
-- 4 --
The C3-product consisted for 49% of propane.
me molar ratio between butane and butane in the product
was 1.9.
Comparative e~Eeriment 1
The experiment of Example 1 was repeated using the same
conditions with the exception of the catalyst not containing
calcium.
me CO-conversion was 30~.
m e hydrocarbon product composition was:
Hydrocarbons Paraffins Olefins i
White White White
Of 6128 126 2
C3 8.1 6.5 1.6
iso-C4 7.3 2.3 5.0
n-C4 2.4 0.4 2.0
C5 2.2 not determine not determined
_
By comparing the results given in the Example with those of
the ccmparati~e experiment it can be concluded that by adding an
alkaline earth metal compound to the catalyst the olefin content
of the product is increased and especially the selectivity to
iso-butene is markedly improved.5 EXEMPT 2
m e experiment of Example 1 was repeated, using the same
conditions, over a catalyst comprising White ZrO2 and White spa
in the form of Boo, and having a surface area of 85 mug which
was the result of a previous calcination step carried out in air
for 2 hours at 500C. me catalyst particles size was from
0.4-0.6 mm. m e CO-conversion to hydrocarbons was 21.5%.
I
-- 5 --
The hydrocarbon product had the following composition:
_ Hydrocarbons Paraffins Olefins
White White White
Clue 41.1
C213.0 6.9 6.1
C35.8 2.3 3.5
is C23.8 6.2 17.6
n-C 8.9 not determined not determined
C57.4 not determined not determined .
EXAMPLE 3
A gaseous mixture of hydrogen and carbon monoxide having a
KIWI molar ratio of 3 was passed over a bed of zirconium
oxide catalyst particles containing 1% by weight of yttrium in
the form of YO-YO and having a specific surface area of 85 mug
which was the result of a previous calcination step carried out
in air for 2 hours at 500C. The catalyst particles size was
from 0.4-0.6 mm.
m e reaction conditions were chosen as follows:
Tem~rature : 450C
Pressure : 80 bar
Gas hourly space velocity: 594 Nl/l.h
The CO-conversion to hydrocarbons was 16~.
The hydrocarbon product had the following composition:
-- 6 --
Hydrocarbons Paraffins Olefins
White White White
Of 27.0 27
C2 6.4 4.8 1.6
C3 6.8 5.5 1 1.3
iso-C4 27.4 5.4 122.0
n-C4 5.8 not determined not determine
C5 26.5 not determined not determine
