CA1258063A - Metal catalysts supported on rutile titania and use thereof - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

A cobalt catalyst, especially a thoria promoted cobalt catalyst, formed by dispersing the cobalt, or cobalt and thoria, upon a titania or titania-containing support wherein the titania support is one having a rutile:anatase ratio of at least about 2:3. By passing methanol or an admixture of carbon monoxide and hydrogen over the catalyst at reaction conditions, a distillate fuel constituted principally for an admixture of linear paraffin and olefins, particularly a C10+-containing distillate can be formed.

Description

` ~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 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~

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 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 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 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 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 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 ~ ~ 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 , . . .

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 , .

~:: 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 ~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 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~

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 ~

J~ ) O O
~_) ~ h O (15(L) ~ ~1 O ~ :- O
C h ~, 1~ 0 o~
aJ O Q
,_1(~ h S
H ~ 3 ~ 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~
,, 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 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 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.

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.

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.

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~

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.

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 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~
., 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~

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 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.

~ 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~

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 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.

Claims (10)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OF PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS

1. A catalyst composition useful for the conversion of methanol or synthesis gas to hydrocarbons characterized in that it consists essentially of cobalt, or cobalt and thoria in catalytically active amount composited with titania or a titania-containing support, wherein the titania support is one having a rutile:anatase ratio of at least about 2:3.

2. A composition according to Claim 1 further characterized in that the catalyst consists essentially of cobalt dispersed on the support, the catalyst containing from about 2 percent to about 25 percent cobalt, based on the weight of the catalyst composition.

3. A composition according the Claim 1 further characterized in that the catalyst consists essentially of cobalt and thoria dispersed on the support, the catalyst containing from about 2 percent to about 25 percent cobalt, and from about 0.1 percent to about 10 percent thoria, based on the total weight of the catalyst composition.

4. A composition according to any one of claims 1-3 further characterized in that the titania support is one having a rutile:anatase ratio ranging from about 2.3 to about 100:1, or greater.

5. A composition according to either of claims 1 and 3 further characterized in that the titania promoted cobalt catalyst contains Co and ThO2 in ratio of Co:ThO2 ranging from about 20.1 to about 1:1.

6. A composition according to any one of claims 1 to 3 further characterized in that said titania support has a rutile:anatase ratio ranging from about 2:3 to about 3:2.

7. A process for the conversion of methanol or synthesis gas to hydrocarbons using the catalyst composition of claim 1 characterized by contacting said catalyst composition at reactions conditions with a feed comprising an admixture of carbon monoxide and hydrogen or a feed comprising methanol to produce a C2+ containing distillate.

8. A process according to claim 7 further characterized in that said feed comprises an admixture of carbon monoxide and hydrogen in a H2:CO molar ratio equal to or greater than about 0.5:1, at a total pressure of equal to or greater than about 95 psia and at a temperature ranging from about 160°C to about 290°C.

9. A process according to claim 7 further characterized in that said feed comprises methanol at a methanol partial pressure of above about 100 psia.

10. A process according to claim 9 further characterized in that said feed further comprises hydrogen in admixture with said methanol in a methanol:
hydrogen molar ratio of above about 2:1.