Note: Descriptions are shown in the official language in which they were submitted.
` ~25~3(316~
BACKGROUND AND PROBL~MS
I. FIELD OF THE INVENTION
This invention relates to catalyst composi-
tion useful for the preparation of liquid hydrocarbons
from synthesis gas, and from methanol and to processes
for such use. In particular, it relates to catalysts
useful in a process wherein Clo+ distillate fuels, and
other valuable products, are prepared by reaction of
carbon monoxide and hydrogen, or methanol, over certain
types of cobalt catalysts.
II. THE PRIOR ART
Methane is often available in large quanti-
ties from process streams either as an undesirable
by-product in admixture with other gases, or as an off
gas component of a process unit, or units. More
importantly, however~ methane is the principle
component of natural gas, and it is produced in
considerable quantities in oil and gas fields The
existence of large methane, natural gas reserves
coupled with the need to produce premium grade trans-
portation fuels, particularly middle distillate fuels,
creates a large incentive for the development of a new
gas-to-liquids process. The technology to convert coal
or natural gas to synthesis gas is well established,
and the conversion of the synthesis gas to hydrocarbons
can be carried out via Fischer-Tropsch synthesis. On
the other hand, the technology is also available to
convert natural gas to methanol, a product of limited
marketability. However, to utilize the existing
technology, there is need or catalysts suitable for
the conversion of methanol to high quality transporta-
tion fuels, particularly middle distillate fuels.
Fischer-Tropsch synthesis for the production
of hydrocarbons from carbon monoxide and hydrogen is
now well known in the technical and patent literature.
-` ~L2$~ 3
-- 2 --
The first commercial Fischer-Tropsch operation utilized
a cobalt catalyst, though later more active iron
catalysts were also commercialized. An important
advance in Fischer-Tropsch catalysts occurred with the
use of nickel-thoria on kieselguhr in the early
thirties. This catalyst was followed within a year by
the corresponding cobalt catalyst, 100 Co:18 ThO2:100
kieselguhr, parts by wei~ht, and over the next few
years by catalysts constituted of 100 Co:18 ThO2:200
kieselguhr and -100 Co:5 ThO2:3 MgO:200 kieselguhr,
respectively. The Group VIII non-noble metals, iron,
cobalt, and nickel have been widely used in Fischer-
Tropsch reactions, and these metals have been promoted
with various other metals, and supported in various
ways on various substrates. Most commercial experience
has been based on cobalt and iron catalysts. The cobalt
catalysts, however, are o~ generally low activity
necessitating a multiple staged process, as well as low
synthesis gas throughput. The iron catalysts, on the
other hand, are not really suitable for natural gas
conversion due to the high degree of water gas shift
activity possessed by iron catalysts. Thus, more of the
synthesis gas is converted to carbon dioxide in
accordance with the equation: ~2 + 2CO~(CH2)X + CO2;
with too little of the synthesis gas being converted to
hydrocarbons and water as in the more desirable
reaction, represented by the equation:
2H20+CO ,~ (CH2) X+H20.
There exists a need in the art for a catalyst
and a process useful for the conversion of methanol,
and synthesis gas, respectively, at high conversion
levels, and at high yields to premium grade transport-
ation fuels, especially C10+ distillate fuels; particu-
larly without the production of excessive amounts of
carbon dioxide.
~25~ 3
III. OBJECTS
It isj accordingly, a primary objective of
the present invention to supply these needs~
IV. THE INVENTION
This object and others are achieved in
accordance with the present invention embodying a
cobalt catalyst, especially a thoria promoted cobalt
catalyst, formed by dispersing the cobalt, or thoria
and cobalt, upon a titania or titania-containing
support wherein the rutile:anatase ratio oE the support
is at least about 2:3 to produce, by contact and
reaction with a feed comprising an admixture of ca~bon
monoxide and hydrogen or with methanol, preferably in
the presence of hydrogen, at reaction conditions, a
distillate fuel constituted principally oE an
admixture of linear parafEin and olefins, particularly
a C2-t and more particularly a Clo+ containing
distillate which can be further refined and upgraded to
high quality fuels, and other products such as mogas,
diesel fuel, jet fuel, and specialty solvents,
especially premium middle distillate fuels of carbon
numbers ranging from about Clo to about C20
The cobalt-titania catalyst, or thoria
:promoted cobalt-titania catalyst is one wherein cobalt~
or cobalt and thoria, i5 composited, or dispersed upon
titania, TiO2, or a titania-containing carrier, or
support, and the titania is one having a rutile:anatas
weight ratio o~ at least about 2:3, as determined by
ASTM D 3720-78: Standard Test Method for Ratio of
Anatase_to Rutile In Titanium Dioxide Pigments sy Use
of X-Rav Diffraction. A preferred, and more selective
__ _ _ d _
catalyst for use in methanol conversion reactions is
one containing titania ~herein the rutile:anatase ratio
ranges from about 2:3 to about 3:2. In its preferred
~æ~
-- 4 --
form the titaniar or titania component of the carrier,
or support, when used in the conversion of synthesis
gas will contain a rutile:anatase ratio of at least
about 3:2; generally from about 3:2 to about 100:1, or
greater, and more preferably from about 4:1 to about
100:1, or greater. The cobalt, or cobalt and thoria,
is dispersed on the support in catalytically effective
amounts. In methanol conversion reactions the use of
thoria with the cobalt is particularly preferred.
In terms of absolute concentration, suitably,
the cobalt is dispersed on the support in amounts
ranging from about 2 percent to about 25 percent,
preferably from about 5 percent to about 15 percent,
based on the total weight of the catalyst composition
(dry basis). The thoria is dispersed on the support in
amounts ranging from about 0.1 percent to about 10
percent, preferably from about 0.5 percent to about 5
percent, based on the total weight of the catalyst
composition (dry basis). Suitably, the thoria promoted
cobalt catalyst contains Co and ThO2 in ratio of
Co:ThO2 ranging from about 20:1 to about 1:1, prefer-
ably from about 15:1 to about 2:1, based on the weight
of the total amount of Co and ThO2 contained on the
catalyst. These catalyst compositions, it has been
found, produce at reaction conditions a product which
is predominately Clo~ linear paraffins and oleEins,
with very little oxygenates. These catalysts provide
high selectivity, high activity and good activity
maintenance in methanol conversion reactions, or in the
conversion of carbon monoxide and hydrogen to
distillate fuels.
In conducting methanol conversion reactions
the partial pressure of methanol within the reaction
:$ æss~3
~ 5 --
mixture is generally maintained above about 100 pounds
per square inch absolute (psia), and preferably above
about 200 psia. It is preferable to conduct the
reaction in the presence of hydrogen which may be added
or ~enerated in situ. Suitably methanol, and hydrogen,
are employed in molar ratio of CH3OH:H2 above about 2:1
and preferably above 8:1, to increase the concentration
of Clo+ hydrocarbons in the product. Suitably, the
CH3OH:~2 molar ratio, where hydrogen is e~ployed,
ranges from about 2:1 to about 60:1, and preferably the
methanol and hydrogen are employed in ~olar ratio
ranging from about 8:1 to about 30:1. Inlet hydrogen
partial pressures preferably range below about 80 psia,
and more preferably below about 40 psia; when hydrogen
is present inlet hydrogen partial pressures preferably
ranging from about 5 psia to about 80 psia, and more
preferably from about 10 psia to about ~0 psia. In
general, the reaction is carried out at liquid hourly
space velocities ranqing from about 0.1 hr~l to about
10 hr~1, preferably froln about 0.2 hr~l to about 2
hr~l, and at temperatures ranging from about 150C to
about 350C, preferably from about 180C to about
250C. Methanol partial pressures preferably range from
about 100 psia to about 1000 psia, more preferably from
about 200 psia to about 700 psia. The product
qenerally and preferably contains 50 percent, or
greater, and more preferably 75 percent, or greater,
Clo+ liquid hydrocarbons which boil above 160C
(320F).
In conducting synthesis gas reactions the
total pressure upon the reaction mixture is generally
maintained equal to or greater than about 95 psia, and
pref rably above about 155 psia, and it is generally
desirable to e~ploy carbon monoxide, and hydrogen, in
molar ratio of H2:CO above about 0.5:1 and preferably
equal to or above 2:1 to increase the concentration of
~2~ 3
-- 6 --
C1ot hydrocarbons in the product. Suitably, ~he Hz:C0
molar ratio ranges from about 0.5:1 to about ~:1, and
preferably the carbon monoxide and hydro~en are
employed in molar ratio H2:C0 ran~ing from about 2:1 to
about 3:1. In general, the reaction is carried out at
gas hourly space velocities rangin~ from about 100
V/~r/V to about 5000 V/Hr/V, preferably from about 300
V/Hr/V to about 1500 V/Hr/V, and at temperatures
ranging rom about 160C to about 290C, preferably
from about 190C to about 260C. Pressures preferably
range from about 95 psia to about 615 psia, more
preferably from about 155 psia to about 415 psia. The
product generally and preferably contains 60 percent,
or greater, and more preferably 75 percentl or greater,
C1o-~ liquid hydrocarbons which boil above 16~C
(320F).
Cobalt-titania, and especially thoria
promoted cobalt-~itania catalysts exhibit high activity
and selectivity in the conversion of methanol, or
conversion of carbon ~onoxide and hydrogen to Clo+
distillate fuels. The catalysts employed in the
practice of this invention are prepared by techniques
known in the art for the preparation oE these and other
catalystsO The catalyst can, or example, be prepared
by gellation, or cogellation techniques. Suitably,
however, cobalt can be composited alone, or with the
thoria, upon a previously pilled, pelleted, beaded,
extruded, or sieved titania or titania-containing
support ~aterial by the impregnation method. In
preparing catalysts, the metal, or metals, is deposited
fro~ solution on the support to provide the desired
absolute amount o~ the metal, or metals. Suitably, the
cobalt is composited with the support by contacting the
support with a solution of a cobalt-containing
compound, or salt, e.g., a nitrate, carbonate or the
like. The thoria, where thoria is to be added, can
~æ$~63
-- 7
then 'oe composited with the support in similar manner,
or the thoria can first be impregnated upon the
support, followed by impregnation o~ the cobalt.
Optionally, the thoria and cobalt can be coimpregnated
upon the support. The cobalt compounds used in the
impregnation can be any organometallic or inorganic
compound which decomposes to give cobalt oxide upon
calcination, such as cobalt nitrate, acetate,
acetylacetonate, naphthenate, carbonyl, or the like
Cobalt nitrate is especially preferred while cobalt
halide and sulfate salts should generally be avoided.
The salts may be dissolved in a suitable solvent, eOg.,
water, or hydrocarbon solvent such as acetone, pentane
or the like. The amount of impregnation solution used
should be sufficient to completely immerse the carrier,
usually within the range from about 1 to 20 times the
carrier by volume, depending on the concentration of
the cobalt-containing compound in the impregnation
solution. The impregnation treatment can be carried
out under a wide range of conditions including ambient
or elevated temperatures. Metal components other than
thorium may also be added as promoters. Exemplary of
such promoters are nickel, platinum, palladium, rhodium
and lanthanium. In general, however, the addition of
these metals have not been found to provide any
significant benefit. In fact, surprisingly, the
addition of copper and iron appear to have had a
somewhat adverse effect upon the reaction. For this
reason, the preferred catalyst is one which consists
essentially of cobalt, or cobalt and thoria, dispersed
upon the titania, or titania-containing support; or, in
other words, catalysts which do not contain a signifi-
can't amount of a metal, or metals, other than cobalt,
or metals other than cobalt and thorium, dispersed upon
the titania or titania-containing support.
Titania is used as a support, or in combin-
ation with other materials for forming a support,
examples of such other materials being non-acidic
-- 8
materials as SiO2, MgO, ZrO2 and A12O3. The titania
used for the support however, is necessarily one which
contains a ruti~e anatase ratio of at least about 2:3,
as determined by x-ray diffraction (ASTM D 3720-78).
The titania supports in catalysts used in the produc-
tion of methanol contain a rutile:anatase ratio of
preferably from about 2:3 to about 3:2. In conducting
synthesis gas conversion reactions, the rutile:anatase
ratio is at least about 3:2. Preferably, when the
catalyst is used in synthesis gas conversion reactions,
the titania contains a rutile:anatase ratio of from 3:2
to about 100:1, or greater, preferably from
about 4:1 to about 100:1, or greater. The surface area
of such forms of titania are less than about 50 m2/g.
These weight concentrations of rutile provide generally
optimum activity, and Clo+ hydrocarbon selectivity
without significant gas and CO2 make.
The catalyst, a~ter impregnation, is dried by
heating at a temperature above about 0C, preferably
between 0C and 125C, in the presence of nitrogen or
oxygen, or both, in an air stream or under vacuum. It
is necessary to activate the cobalt-titania, or thoria
promoted cobalt-titania catalyst prior to use.
Preferably, the catalyst is contacted with oxygen, air,
or other oxygen-containing gas at temperature suffi-
cient to oxidize the cobalt and convert the cobalt to
Co3O4. Temperatures ranging above about 150C, and
; preerably above about 200C are satisfactory to
convert the cobalt to the oxide, but temperatures above
about 500C are to be avoided unless necessary for
regeneration oE a severely deactivated catalyst.
Suitably, the oxidation of the cobalt is achieved at
temperatures ranging from about 150C to about 300C.
The metal, or metals, contained on the catalyst are
then reduced. Reduction is performed hy contact of the
catalystl whether or not previously oxidized, with a
reducing gas, suitably with hydrogen or a
hydrogen-containing gas stream at temperatures above
about 200C; preferably above about 250C. ~uitably,
the catalyst is reduced at temperatures ranging from
about 200C to about 500C for periods ranging Erom
about 0.5 to about 24 hours at pressures ranging from
ambient to about 40 atmospheres. A gas containing
hydrogen and inert components in admixture is
satisfac~ory for use in carrying out the reduction~
The cobalt, and thoria promoted
cobalt-titania catalysts of this invention can be
regenerated, and reactivated to restore their initial
activity and selectivity after use by stripping the
catalyst with a hydrocarbon solvent, or with a gas.
Preferably the catalyst is stripped with a gas, mos~
preferably with hydrogen, or a gas which is inert or
non-reactive at stripping conditions such as nitrogen,
carbon dioxide, or methane. The stripping removes the
hydrocarbons which are liquid at reaction conditions.
Gas stripping can be performed at substantially the
same temperatures and pressures at which the reaction
is carried out. Pressures can be lower however, as low
as a~mospheric. Temperatures can thus range from about
160C to about 290C, preferably from about 190C to
about 260C, and pressures from about 14.7 psia to
about 615 psia, preferably from about 155 psia to about
41~ psia.
If it is necessary to remove coke from the
catalyst, the catalyst can be contacted with a dilute
o~ygen-containing gas and the coke burned from the
catalyst at controlled temperature below the sintering
temperature of the catalyst. The temperature of the
burn is controlled by controlling the oxygen concentra-
tion and inlet gas temperature, this taking into
consideration the amount of coke to be removed and the
i3
-- 10 --
time desired to complete the burn. Generally, the
catalys~ is treated with a gas having an oxygen partial
pressure of at least about 0.1 psi, and preferably in
the range of from about 0.3 psi to about 200, psi to
provide a temp~ra~ure ranging from about 300C to about
550C, at static or dynamic conditions, preferably the
latter, for a time sufficient to remove the coke
deposits. Coke burn-off can be accomplished by Eirst
introducing only enough oxygen to initiate the burn
while maintaining a temperature on the low side of this
range, and gradually increasing the temperature as the
flame front is advanced by additional oxygen injection
until the temperature has reached optimum. Most of the
coke can be readily removed in this way. The catalyst
is then reactivated, reduced, and made ready for use by
treatment with hydrogen or hydrogen-containing gas as
with a fresh catalyst.
The invention will be more fully understood
by reerence to the following examples and demonstra-
tions which present comparative data illustrating its
more salient eatures.
The data given in the examples which follow
were obtained in a s~all fixed bed reactor unit, gas
chromatographic analytical data having been obtained
during the runs which were conducted over various
periods. All parts are in terms of weight units e~cept
as otherwise specified. Feed compositions are
expressed as molar ratios of the components.
The "Schulz-Flory Alpha" is a known method
for describing the product distribution in
Fischer-Tropsch synthesis reactions. The Schulz-Flory
Alpha i5 the ratio of the rate of chain propagation
to the rate of propagation plus termination, and is described fro~
the plot of ln (Wn~n) versus n, where Wn is the wei~ht fraction of
~;~5~ gi3
-- 11 --
product with a carbon number of n. In the examples
~elow, an Alpha value was derived from the C10/C20
portion of the product. The Alpha value is thus
indicative of the selectivity of the catalyst for
producing heavy hydrocarbons from ~he synthesis gas,
and is indicative of the approximate amount of C10+
hydrocarbons in the produc~. For example, a
Schulz-Flory Alpha of 0.80 corresponds to about 35% by
weight of C10~ hydrocarbons in the product, a generally
acceptable level o~ Clc~ hydrocarbons. A Schulz-Flory
Alpha of 0.85, a preferred Alpha value, corresponds to
about 54~ by weight of C10+ hydrocarbons in the
products, and a Schulz-Flory Alpha of 0.90, a rnore
preferred Alpha value, corresponds to about 74~ by
weight of Clo+ hydrocarbons in the product.
The catalysts of this invention used in the
examples below were prepared by the following
procedure: Titania (Degussa P-25*TiO2) was used as the
support for all of the catalysts after mixing with
Sterotex*(a vegetable stearine used as a lubricant and
is a product of Capital City Products Co.), and after
pilling, grinding, and screening to either 60-150 mesh
or 16-20 mesh (Tyler). Two versions of TiO2 were
prepared by calcining portions of the TiO2 in air at
500C and 600C, respectively, overnight. This gave
TiO2 supports with the following properties;
-
Surface
CalcinationRutile:Anatase Area Pore Volume
Temperature, CRatio(l) m2/9 ml/~
500 1.2:1 33 - 36 0.18 - 0.40
600 >30:1 10 - 16 0.11 - 0.15
_
11) ASTM D 372Q-78
Catalysts, of 16-20 mesh size, were prepared from
selected portions o these materials by simple
*Trademark
impregnation of the support with cobaltous nitrate or
perrhenic acid, orboth, from acetone solution using a
rotary evaporator, drying in a vacuum oven at 150C,
and calcining of the catalysts for three hours in
flowing air in a quartz tube. The catalysts were
charged to a reactor, reduced in H2 at 450C for one
hour, and then reacted with syngas or methanol at the
conditions described in the examples.
.
V. EXAMPLES
A. Methanol Conversion
Examples 1 through 6 which follow exemplify
methanol conversion reactions.
In the example which immediately follows a
series of runs were conducted with a thoria promoted
cobalt-titania catalyst to demonstrate the effect of
pressure, notably methanol partial pressure in
converting methanol, and hydrogen to hydrocarbons.
Example 1
A feed constituting an admixture of methanol
and hydrogen in varying molar ratios of CH30H:H2 was
contacted over a thoria promoted cobalt-titania
catalyst (12% Co-2~ ThO2-TiO2) at total pressures
ranging from ambient to 614.7 psia, methanol partial
pressures ranging from 2 to 492 psia, at a temperature
oE 230C and at space velocities of 3500 GHSV and 500
GHSV, respectively. The feed was diluted in certain
cases with carbon dioxide and argon ~Ar); the argon
being added to maintain good operability in terms of
obtaining acceptable material balances. Reference is
made to Table I.
~25~ 3
-- 13 --
~ ~ I
~r ~ I I
g o
I L~ I
~ ~ I
o
' I ~t-
~r ~ I ~ I ~ ~ ~D
I O I o r~
l I ~o~
. I I ~ ~
(~ ~ r1
~D r~ O ~ O r~
fll ~ O U~ ~ ....
~ U~ ~ O ~ O
O l ~ l
, ~ To I ~D U~ U'l ~)
~1 1 7
~oa~
O r- I I 1`
d~ ~r ~r , o , ~r~
r-1 0 1~
r~ o
~ I O ~ O
a
~ O
C~ O O V
O ~ J Co
L~
u~ ~ a) ul r~
a) ` {1~ ) E ~ Co o ~ ~ ,~
~ ~ s ~ o s ~)(n ~ ~ o o
~ ~ L~ ~ ~ ~C V
u~ v ~ ~ a) ~ o
m o ~ o :, ~ ~ ._,
a) E~ ~ E o
G E~
~%~ 3C~3
, . . .
- 14 -
Inlet methanol partial pressures ranging
above about 100 psia, and preferably above about 200
psia, it has been found are required to ensure optimum
conversion of methanol to hydrocarbons. Low inlet
methanol partial pressures favor conversion of methanol
to only H2 and CO with very little hydrocarbon
production. The impact of pressure on conversion and
selectivity are clearly illustrated in Table I. Inlet
methanol partial pressures should range from about 100
psia to about 1000 psia, preferably from about 200 psia
to about 700 psia. Total pressure will depend on the
amount of H2, CO2, or other inerts present in the
reaction mixture.
Low partial pressures of hydrogen are preferred in
order to maximize the yield oE the desired heavy
hydrocarbons at the expense o light hydrocarbons. For
cobalt-titania/ and thoria promoted cobalt-titania
catalysts, the preferred inlet hydrogen partial
pressure is generally maintained below about 80 psia,
and preferably below about 40 psia.
Example 2
Exam~le 1 was repeated utilizing both
cobalt-thoria-titania catalyst, and an unpromoted
cobalt-titania catalyst, at 414.7 psia, GHSV = 500, 40
CH30H:2 H2:1 C02:7 Ar. Reference is made to Table II.
As shown in the table, the selectivity to heavy
hydrocarbons is particularly high, especially at low
temperature.
~S~i3
, .
-- 15 --
~:: o
~: .,~ ~~ ~ a
E~ o ~ ~
I` I ~ ~ ~~ ~ O ~
.. o ~ u~ ~ o ~ I` ~ O
o U
~>
,., _~
.
.. o o o~ CO
~ ~ o ~ . ~ U: . . CO
O Of~ O ' 1-- ' ' ~ O
~ ,~ ~ l~ ~ ~ o o~ 1~ ~ o
:C ~ .
o o
a) ~ ~ .
Q
E~ o . ~
I o o~
O O O
Il 1;~ N ~) ~ t` O ~r 0~ ~ O
~ o~
5: ~
~ O
In o'~
~) V ,5:: 0
0 3 v
a~ o 5::
C ` s~
C~ o C ~ ~ ,,
o _~ V o ~ ~ ~:
~r 0 ~ ~ $
_, ` ~ ~ V V ~,
a)
~ ~ O Q (~ r-l O
::5 C h r1 0 0 ~--
v o a. Ll O C~
0 0 ~ N
~1 a~ 1: O~
0 ~ o .a Q dP :~
V
0 a~ 3 r~s IJ O
~) P C) C,) 3 tJ~
~25~i3
- 16 -
~roln the values given for the Schulz-Flory Alpha, it is
apparent that the conversion of the methanol to heavy
hydrocarbons, and the selectivity of the catlysts for
producing Clo+ hydrocarbons are quite high. The
Co-TiO2 catalyst produces about 58% by weight C10+
hydrocarbons in the product, and the ThO2 promoted
Co-TiO2 catalyst produces a product containing
approximately 65% by weight and 80% by weight Clo+
hydrocarbons, at 230C and 200C, respectively.
Example 3
The product made from the Co-ThO2-TiO2
catalysts consists predominately of linear olefins and
paraffins with a small amount of branched paraffins and
olefins. Reeerence is made to Table III which shows
the distribution of compounds within the C8 eraction
obtained by reaction of the methanol, and hydroc~en,
over the (12% Co-l~ ThO2-TiO2), after 35 hours, at
230C, 414.7 psia, GHSV - 500 and 40 CH30H:2 H2:1 C02 7
Ar.
Table III
Component in C8Wt.~
n-octane 78.2
l-octene 0.6
4-octenes 6.5
2-methylheptane 4.8
3-methylheptane 6.9
4-methlyheptane 3.0
Hydrogen in relatively small amount, as
earlier suggested, is desirable to promote conversion
of the methanol to hydrocarbons. The absolute hydrogen
concentration is also of importance in promoting
conversion, selectivity and yield in the production of
the Clo~ hydrocarbons from methanol. Partial pressures
less than about 80 psia are preferred, and more
63
- 17 -
preferably less than 40 psia, in order to produce the
higher molecular weight liquid hydrocarbons. H2
partial pressures above about 80 psia, or even 40 psia,
favor a lighter, more paraffinic product.
Example 4
An admixture constituted of methanol and
argon to which hydrogen was added in varying concentra-
tions was passed into a reactor charged with a thoria
promoted cobalt-titania catalyst, at 230C, CH30H = 332
psia, argon (83-H2 psia) and GHSV=500. Measurements
were made of the CH30H conversion, and carbon product
distribution in terms of weight percent hydrocarbons,
carbon monoxide, carbon dioxide and dimethyl ether
(DME) formation. The results are given in Table IV.
~2~
-- 18 --
Cl~ . ~ . .
o ~ O u~ o a
InCOOD 0~0~-
Il
,_ ~ ~ ~ D
r ~
.~1 ~ ~ CO O ~n co ~D
H _~ . ~~D
S:~ Ll~ O
~1) O 0
Q ~ o~ o~r ru~
~ ~C dP
~ 3
.~ .,,
.. u~ tn
P~ ~:
. ~ ~
o
U~ Q . Q
~ ~1 h
a) ~ h IU
:r: ~ 3 ~
C) 01 Ul O
tr~ ~ h
~C ~
0 0
J~ ) O O
~_) ~ h
O (15(L) ~ ~1
O ~ :- O
C h ~,
1~ 0 o~
aJ O Q
,_1(~ h
S
H ~ 3
-- 19 --
~ he addition of hydrogen to the reactor, it
will be observed, increases the amount of methanol
conversion. A hydrogen inlet pressure of 17 psia thus
raises the conversion of the methanol by 14 percent
(52%-38~), and the conversion of C2+ hydrocarbons is
increased by 6.5 percent (Bl.1%-7406%). Increasing the
inlet hydrogen partial pressure to 83 psia raises the
amount of methanol conversion an additional 31 percent,
viZo r from 52 wt. % to 83 wt. ~. However, C2+
hydrocarbon selectivity is decreased somewhat, i.e.,
from 81.1 wt. % to 70.9 wt. %. Moreover, the
hydrocarbon product is somewhat lighter, as indicated
by the higher methane, and a Schulz-Flory Alpha of 0082
is obtained.
xample 5
A series of runs were made, at similar
conditions, by contact of methanol with fixed beds oE
catalyst, as identified in Table V, contained in a
stainless steel tube reactor. The runs were conducted
at 230C, 414.7 psia, GHSV = 500 and 40 CH30H:2 H2:1
C02:7 Ar. Measurements were made of the CH30H
conversion with each of these catalysts, and analysis
made of the wt. % carbon product distribution in terms
of C0, C02, dimethyl ether, CH~ and C2~ hydrocarbons.
The wt. % methane that was produced was also recorded.
Reference is made to Table V.
~;25i~
,,
-- 20 --
Table V
230C~ 414.7 psia, GHSV= 500, 40 CH3O~1:2 H2:1 C02:7 AR
W~. ~
C~130HCarbon Product CH4 in
Con~7er- Distribution, Wt. % Hydro-
Catalyst sionCO ~ ~~ carbons
12% Co-2% ThO2-- 70 2.9 12.6 0.5 7.4 76.6 8.8
Tio2
100 Co:5 ThO2; 97 1.0 38.4 -- 19.5 41.1 32.2
8 MgO:200
Kieselguhr(l)
9 Co:l Cu:2 2û 16.7 42.4 0.2 5~2 35.5 12.8
ThO2(2)
12% Co-SiO2 38 ~.3 22.3 0.1 7.0 66.3 9.6
12% Co-~u2o3 64 2.8 21.8 2.~ 9.9 63.1 13.6
(1) Prepared by procedure given at page 137 and
ollowing; The Fischer-Tropsch _nd Related
Syntheses, Storch, Golumbic and Anderson, John
Wiley and Sons, Inc., New York (1951).
(2) Shima, K.; Morita, T.; Mujazoki Diagaku Kogakuba
Kenkyu, 25 19-24 (1979).
These data show that the thoria promoted
cobalt-titania catalyst, as contrasted with prior art
cobalt catalysts, is clearly the superior catalyst. It
produces high conversion o the methanol (70 wt. %),
and high produckion of C2+ hydrocarbons (76.6 wt. %)
with low Inethane in the carbon product distribution
(8.8 wt. 2;). Whereas the 100 Co:5 ThO2:8 MgO:200
Kieselguhr ca~alyst provides extremely high conversion
of the methanol (97 wt. %), the production of C2+
hydrocarbons (41.1 wt. ~) is extremely low, and the
production of CO2 is unacceptably high (38.4 wt. ~).
Essentially one-third (32.2 wt. %) o the total
hydrocarbons that are produced is methane. The
~2~ 3
- 21 -
methanol conversion level (20 wt. %~ of the 9 Co l Cu:2
ThO2! albeit a thoria promoted cobalt catalyst, is
abysmal; and the CO2 production level (42.4 wt. %)
unaccep~able. Only 35.5 wt. % of the carbon product
distribution is hydrocarbons. The me~thanol conversion
level of the 12% Co-SiO~ (38 wt. ~) is likewise poor,
with fairly high production of CO2 (22.3 wt. %~. The
12% Co-Al2O3 catalyst, while superior to the 9 Co:l
Cu;2 ThO2 and 12~ Co-Sio2 catalysts, provides only 64
wt. % conversion of the methanol, with high production
of C2 (21.8 wt~ ~). The C2+ hydrocarbons product make
is only 63.1 wt. % as co~pared with 76.6 wt. ~ for the
12% Co-2~ ThO2-TiO2 catalyst.
The following data show the effect of
different rutile contents on cobalt-titania catalysts
used in the conversion of methanol to hydrocarbons.
Thus, two 12~ Co-TiO2 catalysts, identical except that
the TiO2 base used to form one catalyst had a
rutile:anatase weight ratio of 1.2:1, and the other a
rutile:anatase weight ratio greater than 30:1, were
used to convert methanol to hydrocarbons. The runs,
made at identical conditions, were made at 230C, 414.7
psia, GHSV = 500 and 40 CH30H:2 H2:1 C02:7 Ar.
Reference is made to Table VI.
~5~ 3
- 22 -
Table VI
Effect of Rutile Content on I2
Co-TiO~ Catalysts
230C, 414.7 psia, GHSV = 500,
~10 CH30H:2 H2:1 Co2:7 AR
TiO2 Properties
Rutile:Anatase Ratio, Wt. 1.2:1 >30.1
Surface Area, m2/g 36 10
Pore Volume, ml/g 0.30 0.11
C~30H Conversion 66 100
Carbon Product Distribution, Wt.%
CO 2.6 0.8
C2 15.6 27.8
CH4 9.0 17.1
c2+ 72.8 5~.3
These data clearly show that the catalyst
which contai-ns 1.2:1 ratio of rutile:anatase is the
superior catalyst. Albeit the catalyst which contains
a weight ratio of >30:1 rutile:anatase provides higher
conversion, the methane gas make is almost double that
of other catalyst (17.1% vs. 9.0%), and the catalyst is
far less selective in the production of C2+
hydrocarbons (54.3~ vs. 72.8~) r Moreover, the catalyst
which contains >30:1 rutile:anatase is more active in
converting the methanol to carbon dioxide (27.8% vs.
15.h~).
B. S nthesis Gas Conversion
Y
Examples 7 through 9 which follow exemplify
synthesis gas conversion.
63
- 23 -
In the example which immediately follows a
series of runs were conducted with several known
Fischer-Tropsch catalysts, these being compa~ed with a
run using a cobalt-titania catalyst to demonstrate the
particularly high effectiveness oE the latter in
converting synthesis gas to hydrocarbons.
EXAMPLE 7
A feed constituted of an admixture oE carbon
monoxide and hydrogen in molar ratio of H2:C0 of 2:1
was contacted over a cobalt-titania catalyst (Catalyst
A; 12% Co-TiO2; 0.9:1 rutile:anatase) and several known
cobalt catalysts, viz., 100 Co:5 ThO2:8 MgO:200
kieselguhr (Catalyst B), 12% Co/SiO2 (Catalyst C) and
25 Co:1.8 Ti:100 SiO2 (Catalyst D), respectively~ at
temperature of 230C, at a pressure of 164.7 psia, and
at a space velocity oE 400 hr~l. The data shown in
Table VII demonstrate the level of CO conversion 70
hours after initiation of the runs, the CO2
selectivity, CH4 selectivity, C2~ selectivity, and the
Shulz-Flory Alpha value, which is a measure of the
ability of a catalyst to produce Clo~ hydrocarbons.
-- 24 --
N ~ f~
~ ~ ~ In ~
:~ o Dci~
. I o
U~ ~ ~ O I O O
~1
Il ~ 0~ ~
O ~ V . . . . ~:S ~ C
~) t~ o ~ ~ ~ ~: ~ S
c~u~3 ~ ~ o
0 .
_ .
'> h ~ oP ~ CO O
~1 S 3 a~ ' \D r- ~ ~ U
O C~ ~ 3 ~ 1 ~ a~
~n ~A N D ~1 ~ ~D ~ S C --
H O O ~) . ~ ,~, ~ . ~ h
H . rl . tl~ 3 ~ h e
O O . h U7 ~--o/ z
~` ~ O h 3: a) r~1 N ~ .
1 ~;r ~ aJ ) ~ ~ N r~ 5 14
o ~ Vo ~ C V
V 11 V C~ h E-~ ~,
a ~ ~ v u~
~ ~ .. ~ ~'` O
U~ ~ ~I ,. n
N . ~ N
ll ~, ~ m O N. ~ ~ . 0 o 5:: o
E~ ~ o J~ ~ O ~ C~ ~ O U~ a
u~ 7u1 tn t ) h V ~ ~
~o~O ~o s~o~ :~ O C~ 3
N ~l o~ N ~ In O
~ ~ ~ ~ co ~ ~ ~ ~ ~
v JJ
f~
- 25 -
These data thus clearly show that Catalyst A~
the Co/TiO2 catalyst, is unique as re~ards its superior
activity and selectivity. Moreover, the high
Shulz-Flory Alpha value indicates an ability of this
catalyst to produce in the product more than about 75
Clo+ hydrocarbons.
The following data show that the rutile
content oE the TiO2 support from which the catalyst is
formed is significant, the CO conversion of the
catalyst increasing as the rutile content of the TiO2
support is increased.
The following example demonstrates the effect
of the rutile content of the TiO2 supports from which
cobalt-titania catalysts are formed, and the effects oE
the cobalt metal distribution upon the surface of the
supports. In a Eirst pair oE runs, the rutile content
of one support from which a catalyst is ormed has a
rutile:anatase ratio of 1.2:1, and the ot-her a
rutile:anatase ratio >30:1 In a second pair of runs,
the rutile:anatase ratio of one support from which a
catalyst is formed is about 1.2:1, and the other >30:1.
EXAMPLE 8
Two 12~ Co/TiO2 catalysts were formed fcr use
in a first pair of side-by-side runs by impregnating
cobalt upon two portions of TiO2 16-20 mesh (Tyler)
particles, the first portion having a rutile:anatase
ratio of about 1.2:1 and the other a rutile:anatase of
>30:1. Reference is made to Table VIII, Columns 2 and
3. Two additional portions of a 16-20 mesh (Tyler)
TiO2 were similarly impregnated with cobalt, the first
hav;ng a rutile:anatase ratio of about 1.2:1 and the
other a rutile:anatase ratio of >30:1. Reference is
made to Table VIII, Columns 4 and 5. The first pair of
~2~il!3~63
- 26 -
catalysts (Columns 2 and 3) were similarly dried, and
then calcined in air for 3 hours at 250C. The second
pair of catalysts (Columns 4 and 5) were then similarly
dried and then calcined in air for 3 hours at 500Co
These catalysts were then charged in equal quantities
to the fixed bed reactor as previously described,
reduced with hydrogen, and separate runs made with each
catalys~ at identical conditions, viz., 200C, 294.7
psia, GHSV = 1000 and H2:CO of 2.15:1. The following
data was taken aEter 20 hours operation, reference
again being made to Table VIII.
5~
.,
-- 27 --
o
o ~ o . ~, . ~
~ o o r~ o
~ ~ o ~r . I o ,-
~ O ~ ~ o In u~
C~ ~ ~
~ ~ . ~ Ln o~
O ~o u~
~ ~ o
r C~ 11 ~
U c ~ ~ o t~ ) o cr,
H ~_1 C (1~
~ ~ 3 ~ 3
E~ O ~ ~r o`
lJ ~n a~ ._,
o a
c~ ~ ~ ,_ ~n
~ :~: o ~ a.) a.) : O ~ ~1
~ ~ f~ E ~ ~ ` (IS
O :E ~ o ~
C N ~' 3 ' ~ C_) C ) U~ Ut
O ,~
'~ 0 0 ~I
E~ o
~;25~
- 28 -
The catalysts having the higher rutile
content, or catalysts having the better cobalt metal
dispersion (as measured by conventional dynamic 2
chemisorption), are significantly more active in
converting the CO and H2 to hydrocarbons; albeit it
will be noted, the gas and CO2 content of the catalysts
having the higher rutile content are slightly debited,
and the C2+ hydrocarbons content of the product
slightly lower.
EXA~PLE 9
In another series of demonstrations, cobalt
was dispersed on portions of 60-150 mesh (Tyler)
titania by the heat decomposltion of a cobalt carbonyl
compound, Co2(CO)g; deposited from a pentane solution;
a procedure descrihed by reEerence to articles by A. S.
Lisitsyn, V. L. Kuznetsov, and Yu. 1. Ermakov entitled
(1) "Catalysts Obtained By The Reaction of
Transition-Element Organometallic Compounds With
Oxide-Support Surfaces, Hydrogenation of Carbon
Monoxide on Catalysts Supports" and (2) "Catalysts
Obtained By The Reaction Of Transition Element
Organometallic Compounds With Oxygen-Support Surfaces.
Catalytic Properties of 5ystems Prepared By The
Pyrolysis of Co(Co)g on Oxide Supports In The Reaction
CO + H2 Depending On Their Composition And Pretreament"
Institute of Catalysis, Siberian Branch of the Academy
of Sciences of the USSR, Novosibirsk. Translated from
Kinetika i Kataliz, Vol. 23,_ No. _~ pp. 919-931,
July-August, 1982. August, 1982. Two of these
catalysts, referred to in columns two and three in
Table IX were prepared from TiO2 having a
rutile:anatase ratio of 1:2.6 (110 m2/gm surface area),
and are believed representative of prior art catalysts,
and three of these catalysts referred to in columns
four, five, and six were prepared from TiO2 containing
a rutile:anatase ratio >30:1. A sixth catalyst was
prepared from cobalt nitrate, by impregnation of a TiO2
support material having a rutile:anatase ratio >30:1
63
- 29 -
with a cobalt nitrate in acetone solution. The several
catalysts, each of which con~ained between 9.3 wt. %
and 11.1 wt. ~ cobalt as shown by analysis, were
pretreated (1) at temperatures approximating 250C for
one hour in vacuum, or (2) in air at ~his temperature
for three hours followed by a one hour period of
treatment at 450C with hydrogen, or (3) with hydrogen
at 450 for one hour, as shown in the Table. Reference
is made to Table IX.
63
-- 30 --
~ O O
~ o o
Ln ~ ., ) O (-' ,CU'l
~ Z A
C~l ~:
~
O ~: '
~1 0
o ~ o
t~ R
:I: ~ ~ O ~ S
o ~ ~ ~ ~
O ~ C > A I: ~1 ~ I,-
o
,_1 ~1 0
~I ~ Ln O
> O .-1 ~`I O
U~ ~ . . 4 u~ h
~.C ~r .~ ~ u~
, O
ar c ) A ~ I
Q. ~ O
~ ~` ~ ~1 0 .
~ ~ Q ~ O h ~
.¢ ~ ~~ o ~ s cn
E~ ~ co ~ ) A
Co)
O
O
~I r~l O I .
,. ~ ~ U~ O
U~ O W ~ U~
u~ 4 t~ r
:~ o ~ ~ 1 ~ I
~) ~ O
:~
U~ C I V
O
5~ O L~
~ 4 N r~ .C
O , ~ .- In C ~
O JJ
u~
o :~
~ ~o ~, .,~ ~
0 ~ J
~ ~ 0
J~ h N
15 ~ (U a ~o o
:~ C O E~
C) a) E o
E~ ) E
d~ Or-l IIJ h o~
U~,~ O J~ O U~ ~.) `'
~ V ~1
J.J O ::~ h O
3 ~ p s o
~L2~8~16~
- 31 -
These data clearly show that the amount of
conversion of the feed to hydrocarbons is very, very
low with the cat~lysts prepared from a TiO2 base
containing a rutile:anatase ratio of 1:2.6 viz., 30
percent when the catalyst is treated at 257C for 1
hour under vacuum as described by the reference
procedure, supra. It is even poorer, viz., 5 percent,
when the catalyst is pretreated with air and then
reduced in accordance with the process of this
invention. Methane make is very, very high in either
instance, viz., 13 5 percent and 1501 percent, respec-
tively. The superior performance of the catalyst
formed Erom the high rutile:anatase Tio2 support is
particularly manifest when the % C0 conversion between
the catalysts formed from the low rutile:anatase TiO2
support (30% and 5%, respectively) is compared with the
% C0 conversions obtained with the catalyst formed ~rom
the high rutile:anatase TiO2 supports (5g~, 97%, 93%
and 95%, respectively). The CO conversion is poor
because the poor dispersion of the cobalt, as
determined by the 02-chemisorption data.
In pretreating a catalyst of this invention,
wherein the cobalt of the of thee starting cobalt
carbonyl compound is dispersed on a TiO2 base having
rutile:anatase ratio of >30:1, the performance of the
catalyst is drastically improved. Pretreating in
accordance with the reference procedure, the percent C0
conversion to hydrocarbons is essentially doubled,
viz., 59 percent vis-a-vis 30 percent and methane make
is drastically reduced, viz., from 13.5 percent to 4.9
percent. When the preferred pretreat of the present
invention is e~ployed, i.e., air activation followed by
hydrogen reduction, the percent C0 conversion rises to
97 percent, with only 5.~ percent methane production;
and even when a similar catalyst is reduced without a
preceeding air treat, 93 percent CO conversion is
obtained, with only 5 6 percent gas make.
~25~163
- 32 -
The Co impregnated catalyst produced from a
TiO2 base having a rutile:anatase ratio >30.1,
pretreated with both air and hydrogen, provides 95
percent selectivity of the CO to hydrocarbons, with a
gas make of only 4.5 percent.
These reactions can be conducted with these
catalysts in fixed bed, or slurry bed reactors with or
without the recycle of any unconverted gas and/or
liquid product. The Clo+ product that is obtained is
an admixture of linear paraffins and olefins which can
be further reEined and upgraded to high quality middle
distillate fuels, or such other products as mogas,
diesel fuel, jet fuel, specialty solvents and the like.
A premium grade middle distillate fuel of carbon number
ranging from about Clo to about C20 can also be
produced from the Clo+ hydrocarbon product. The
catalyst is constituted of cobalt or cobalt and thoria
supported on a rutile form of TiO2 or
rutile-titania-containing support which can contain
such non-acidic materials as SiO2, MgO, ZrO2, Al2O3.
The catalyst is preferably reduced with a H2-containing
gas at start-up.
