JP2003517913A - Improved Fischer-Tropsch activity for cobalt on alumina catalyst without promoter - Google Patents

Abstract

1. A cobalt catalyst for hydrocarbon synthesis on Fischer-Tropsch, said cobalt catalyst comprising cobalt supported on a gamma-alumina support, wherein said cobalt catalyst is not promoted with any noble metals, rhenium, technetium or titanium supported on said a gamma-alumina support, said gamma-alumina support includes a dopant in an amount effective for increasing the activity of said cobalt catalyst for said hydrocarbon synthesis. 2. The cobalt catalyst of claim 1, wherein said amount of titanium dopant is an amount effective to render said cobalt catalyst at least 60% as active as a promoted catalyst which is identical to said cobalt catalyst except that said promoted catalyst is promoted with ruthenium in a ruthenium to cobalt weight ratio of 1: 40. 3. The cobalt catalyst of claim 2, wherein said amount of said titanium dopant is an amount effective to render said cobalt catalyst at least 70% as active as said promoted catalyst. 4. The cobalt catalyst of claim 3, wherein said amount of said titanium dopant is an amount effective to render said cobalt catalyst at least 80% as active as said promoted catalyst. 5. The cobalt catalyst of claim 1, wherein said amount of said titanium dopant, expressed as elemental titanium, is at least 500 ppm by weight of the total weight of said gamma-alumina support. 6. The cobalt catalyst of claim 1, wherein said amount of said titanium dopant, expressed as elemental titanium, is in the range of from about 800 to about 2000 ppm by weight of the total weight of said gamma-alumina support. 7. The cobalt catalyst of claim 1, wherein said amount of said titanium dopant, expressed as elemental titanium, is about 1000 ppm by weight of the total weight of said gamma-alumina support. 8. The cobalt catalyst of claim 1, wherein said cobalt catalyst is an activated catalyst which has been reduced in the presence of hydrogen and at a water vapor partial pressure effective to increase said activity of said cobalt catalyst. 9. The cobalt catalyst of claim 1, wherein said cobalt catalyst is promoted with at least one of potassium and lanthana. 10. The cobalt catalyst of claim 1, wherein said gamma-alumina support is produced from synthetic boehmite and said dopant is added to said gamma-alumina support prior to the crystallization of said synthetic boehmite. 11. A process for producing a hydrocarbon comprising the step of reacting a synthesis gas in the presence of a cobalt catalyst wherein said cobalt catalyst comprises cobalt supported on a gamma-alumina support; said cobalt catalyst is not promoted with any noble metals, rhenium, technetium or titanium supported on said gamma-alumina support and said gamma-alumina support includes a dopant in an amount effective for increasing the activity of said cobalt catalyst for said hydrocarbon synthesis on Fischer-Tropsch. 12. The process of claim 11, wherein said amount of said titanium dopant is an amount effective to render said cobalt catalyst at least 60% as active for said hydrocarbon synthesis as a promoted catalyst which is identical to said cobalt catalyst, except that said promoted catalyst is promoted with ruthenium in ruthenium to cobalt weight ratio of 1: 40. 13. The process of claim 12, wherein said amount of said titanium dopant is an amount effective to render said cobalt catalyst at least 70% as active as said promoted catalyst. 14. The process of claim 12, wherein said amount of said titanium dopant is an amount effective to render said cobalt catalyst at least 80% as active as said promoted catalyst. 15. The process of claim 11, wherein said amount of said titanium dopant, expressed as elemental titanium, is at least 500 ppm by weight of the total weight of said gamma-alumina support. 16. The process of claim 11, wherein said amount of said titanium dopant, expressed as elemental titanium, is in the range of from about 800 to about 2000 ppm by weight of the total weight of said gamma-alumina support. 17. The process of claim 11, wherein said amount of said titanium dopant, expressed as elemental titanium, is about 1000 ppm by weight of the total weight of said gamma-alumina support. 18. The process of claim 11 further comprising the step, prior to said step of reacting, of activating said cobalt catalyst by reducing said cobalt catalyst in the presence of hydrogen and at a water vapor partial pressure effective to increase said activity of said cobalt catalyst. 19. The process of claim 18, wherein said water vapor partial pressure is in the range of from 0 to about 0.1 atmospheres. 20. A cobalt catalyst for hydrocarbon synthesis comprising cobalt supported on a gamma-alumina support, wherein said cobalt catalyst is not promoted with any noble metals, rhenium, technetium or titanium supported on said gamma-alumina support, said gamma-alumina support includes an amount of a titanium dopant, and said cobalt catalyst has been reduced in the presence of hydrogen at a water vapor partial pressure effective to increase the activity of said cobalt catalyst for said hydrocarbon synthesis. 21. The cobalt catalyst of claim 20, wherein said gamma-alumina support includes an amount of a titanium dopant of at least 500 ppm by weight, expressed as elemental titanium, of the total weight of said gamma-alumina support. 22. The cobalt catalyst of claim 21, wherein said amount of said titanium dopant, expressed as elemental titanium, is in the range from about 800 to about 2000 ppm by weight of the total weight of said gamma-alumina support. 23. The cobalt catalyst of claim 21, wherein said gamma-alumina support is produced from synthetic boehmite and said dopant is added to said gamma-alumina support prior to the crystallization of said synthetic boehmite. 24. A process for hydrocarbon synthesis comprising the following steps: (a) reducing a cobalt catalyst in the presence of hydrogen and at a water vapor partial pressure effective to increase the activity of said cobalt catalyst for said hydrocarbon synthesis, wherein said cobalt catalyst comprising cobalt supported on a gamma-alumina support, said gamma-alumina support includes an amount of a titanium dopant, and (b) reacting a synthesis gas in the presence of said cobalt catalyst, wherein said cobalt catalyst is not promoted with any noble metals, rhenium, technetium or titanium supported on said gamma-alumina support. 25. The process of claim 24, wherein said gamma-alumina support includes an amount of a titanium dopant of at least 500 ppm by weight, expressed as elemental titanium, of the total weight of said gamma-alumina support. 26. The process of claim 25, wherein said amount of said titanium dopant, expressed as elemental titanium, is in the range of from about 800 to about 2000 ppm by weight of the total weight of said gamma-alumina support. 27. The method of improving the activity of a cobalt catalyst for hydrocarbon synthesis, comprising said cobalt supported on said gamma-alumina support, said method comprising the step of including in said support a titanium dopant in an amount, expressed as elemental titanium, of at least 500 ppm by weight of the total weight of said alumina support.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. TECHNICAL FIELD The present invention relates to systems and methods for carrying out hydrocarbon synthesis, and cobalt on alumina catalysts employed in such methods.

2. BACKGROUND In the Fischer-Tropsch process, a synthesis gas containing carbon oxide (s) and hydrogen ("syngas") is reacted in the presence of a Fischer-Tropsch catalyst to produce liquid hydrocarbons. Certain advanced cobalt catalysts have been shown to be very effective for Fischer-Tropsch synthesis. However, for these catalysts, many enhancements with noble and / or near noble metals are effective to achieve acceptable Fischer-Tropsch conversion activity in order to enhance the reduction (potential) of cobalt to the extent that Has been needed. In part, these cobalt catalysts were typically quite expensive because of the cost of obtaining and adding such promoters. Therefore, to significantly reduce the cost of cobalt catalysts that are useful for Fischer-Tropsch synthesis and to maintain at least comparable activity levels to those previously obtained by promoting such catalysts with precious metals. The need for means still exists.

[Syngas (syn) used in the Fischer-Tropsch process]
gas) "is produced, for example, during coal gasification. Methods for obtaining syngas from many hydrocarbons such as natural gas are also well known. Chu et al., U.S. Pat. No. 4,423,265.
No. 4,088,049, the main methods for producing syngas are (a) partial combustion of hydrocarbon fuel with oxygen-containing gas, (b) reaction of hydrocarbon fuel with steam, or (c) combination of these two reactions. It depends on either of the above. Benham
U.S. Pat. No. 4,423,265, et al., Describes two major methods, namely steam reforming and partial oxidation. The Ensaai Clopedia of Chemical Technology, Second Edition, Volume 2, pp. 3553-433 (1996).
: Interscience Publishers, New York City, NY and Third Edition, Volume 11, pages 410-446 (1980: John Willie &.
Sands, New York City, NY) is said to include an excellent summary of gas production, including synthesis gas production, according to Chu et al.

It has long been recognized that it can be converted to hydrocarbons by catalytic hydrogenation of syngas carbon monoxide. General Chemistry of the Fischer-Tropsch synthesis process is as _{follows: (1) CO + 2H 2} → (-CH 2 -) + H 2 O (2) 2CO + H 2 → (-CH 2 -) + CO 2 The type and amount of reaction products obtained by Fischer-Tropsch synthesis, ie, carbon chain length, can vary depending on the kinetics of the process and catalyst selection.

Many attempts at obtaining effective catalysts for the selective conversion of syngas to liquid hydrocarbons have been disclosed. US Patent No. 5,2 to Soled et al.
No. 48,701 gives an overview of related prior art. The two most popular types of catalysts used to date in the Fish-Tropsch synthesis were iron-based catalysts and cobalt-based catalysts. Benham et al., US Patent No. 5,324,
No. 335, iron-based catalysts promote the overall reaction shown in (2) above due to their high aquatic gas shift activity, and cobalt-based catalysts have the reaction formula (2)
) Is being considered.

What has recently been practiced is the loading of catalyst components on porous inorganic refractory oxides. Particularly preferred carriers were silica, alumina, silica-alumina, and titania. In addition, other refractory oxides from Groups III, IV, V, VI and VIII have been used as catalyst supports.

As noted above, a widespread practice is to convert the promoter to a supported catalyst. Promoters have typically included ruthenium and near noble metals. Promoters are known to increase the activity of the catalyst, and sometimes to make the catalyst 3 to 4 times more active than its non-promoter equivalent. Unfortunately, effective promoter materials are typically both very expensive to obtain and to add to the catalyst.

Current cobalt catalysts are typically prepared by impregnating a support with a catalytic material. As described in US Pat. No. 5,252,613 to Chang et al., A typical catalyst preparation involves the impregnation of a titania, silica, or alumina support, for example with cobalt nitrate by precursor wetting or other known methods. And optionally impregnated with accelerator material before or after. The excess liquid is then removed and the catalyst precursor is dried. Following drying, or as a sequence thereof, the catalyst is calcined to convert the salt or compound to its corresponding oxide. The oxide is then reduced by treatment with hydrogen, or a hydrogen-containing gas, for a time sufficient to substantially reduce the oxide to the catalytic form of the element or metal. Long U.S. Pat. No. 5,498,638 relates to U.S. Pat. No. 4,673.
, 993, 4,717,702, 4,477,595, 4,663
, 305, 4,882,824, 5,036,032, 5,140
, 050 and 5,292,705 disclose known catalyst preparation methods.

Fischer-Tropsch synthesis has hitherto been carried out in fixed bed reactors, gas-solid state reactors,
It has been mainly practiced in gas entrained fluidized bed reactors, with fixed bed reactors being the most used. Dyer et al., U.S. Pat. No. 4,670,472, provides a bibliographic bibliography of several documents describing these systems.

However, recently, significant efforts have been directed towards carrying out Fischer-Tropsch synthesis in three-phase (ie solid, liquid and gas / vapor) reactors. One such system is the slurry bubble column reactor (SBCR). SB
In CR, catalyst particles are slurried in liquid hydrocarbons in a reactor chamber, typically a tower. The syngas is then introduced through the bubble-generating distribution plate at the bottom of the column. The gas bubbles pass upward into the tower, creating a favorable turbulence,
At the same time, it reacts in the presence of a catalyst to produce liquid and gaseous hydrocarbon products. The gaseous product is collected at the top of the SBCR, while the liquid is recovered through a filter that separates liquid hydrocarbons from the catalyst fines. U.S. Pat. Nos. 4,684,756, 4,788,222, 5,157,054, 5,348,982 and 5,527,473 refer to systems of this type, The relevant patents and literature are given.

It has been recognized that carrying out Fischer-Tropsch synthesis using the SBCR system offers significant advantages over the reaction systems conventionally used in the past. Ri
The potential benefit of the slurry process over the fixed bed process described in US Pat. No. 4,788,222 by Ce et al. is a better control of the exotherm produced by the Fischer-Tropsch reaction. , And better maintenance of the catalyst by being able to carry out continuous recycle, recovery and regeneration operations. US Pat. Nos. 5,157,054, 5,348,982, 5,527,47
Issue 3 also considers the advantages of the SBCR process. However, the slurry bubble column process is expensive to operate, in part due to the cost of the required catalyst.

SUMMARY OF THE INVENTION The present invention provides "promoter-free" cobalt on alumina catalysts that unexpectedly and surprisingly have a conversion activity that is at least comparable to that of the best promoted catalysts. The catalyst of the present invention also exhibits excellent product selection properties and is particularly effective for use in SBCR processes and other three-phase reaction systems. This significant finding significantly reduces the cost of the Fischer-Tropsch conversion process, as the more expensive promoters are not needed to achieve acceptable results.

In one aspect, the invention provides a cobalt catalyst for hydrocarbon synthesis.
The cobalt catalyst comprises cobalt supported on γ-alumina. The catalyst is not promoted by any precious metal or by any nearby precious metals. However, the γ-alumina support contains a dopant in an amount effective to increase the activity of the catalyst for hydrocarbon synthesis. The dopant is preferably a titanium dopant.

In another aspect, the present invention provides a method for synthesizing hydrocarbons, which comprises reacting syngas in the presence of a cobalt catalyst. The cobalt catalyst comprises cobalt supported on γ-alumina. The catalyst is not promoted by any precious metal or by any nearby precious metals. However, the γ-alumina support contains a dopant in an amount effective to increase the activity of the catalyst for hydrocarbon synthesis. The dopant is preferably a titanium dopant.

In yet another aspect, the present invention provides a cobalt catalyst for hydrocarbon synthesis comprising cobalt supported on a γ-alumina support. The cobalt catalyst is not promoted by any precious metal or by any nearby precious metals. However, the cobalt catalyst has been reduced in the presence of hydrogen at a steam partial pressure effective to increase the activity of the cobalt catalyst for hydrocarbon synthesis. The water vapor partial pressure is preferably in the range of 0 to 0.1 atm. In yet another aspect, the invention is a hydrocarbon synthesis process; (a) a steam catalyst partial pressure effective to increase the activity of a cobalt catalyst in the presence of hydrogen and the cobalt catalyst for hydrocarbon synthesis. And (b) reacting syngas in the presence of the cobalt catalyst; The cobalt catalyst is not promoted by any precious metal, nor is it promoted by any nearby precious metal.

In yet another aspect, the present invention also provides a method for improving the activity of a cobalt catalyst having an alumina support for hydrocarbon synthesis. The cobalt catalyst is not promoted by any precious metal or by any nearby precious metals. However, the alumina carrier comprises titanium dopan, expressed as elemental titanium, in an amount of at least 500 ppm by weight of the total alumina.

Further objects, features and advantages of the present invention will become apparent upon a review of the accompanying drawings and upon reading this polishing, spine embodiment below. Detailed Description of the Preferred Embodiments Catalyst Composition The present invention provides supported catalysts that are well suited for use in Fischer-Tropsch synthesis. These catalysts are well suited for use in slurry bubble column reactor processes. Preferred examples of general catalysts provided by the present invention include, but are not limited to: (a) supported on preferably doped γ-alumina and promoted by any noble or near noble metal. Cobalt, and (b) one or more selectivity promoters (preferably alkali promoters and / or rare earth oxides such as lantana), but by any noble metal or near noble metal. Is also unpromoted, preferably doped γ
—Cobalt supported on alumina.

A preferred catalyst composition is from about 10 to about 65 pbw (per 100 parts by weight of carrier).
Cobalt; about 0.1 to about 8 pbw potassium (if present); about 0.5
To about 8 pbw lantana (if present). The catalyst is most preferably about 17 to about 45 pbw (more preferably about 20 to about 40 pbw, most preferably about 30 pbw) cobalt (per 100 parts by weight of carrier); about 0.2.
To about 1.0 pbw of potassium (if present); and / or about 0.9 to about 2.1 pbw of lanthana (if present).

Catalyst Carrier The carrier used in the catalyst of the present invention is preferably γ-alumina. We have found that for cobalt catalysts used in both fixed bed and slurry bubble column reactor systems, the specific hydrocarbon employed has little or no effect on product selectivity and overall hydrocarbons. It has been found that it plays a major role in influencing the production rate (ie, catalyst activity). The order of catalytic activity is generally as follows: Al ₂ O ₃ > S
iO ₂ >> TiO _2. The alumina source used and the pretreatment procedure also play a major role in determining the performance of the resulting cobalt-based Fischer-Tropsch catalyst.

The titania supported cobalt catalyst, with or without promoter, was found to have poor Fischer-Tropsch synthesis properties in both fixed bed and SBCR systems. Compared to gamma-alumina and silica, titania supports have a much lower surface area and pore volume. Therefore, the latter does not easily hold high cobalt loadings.

Although silica supports have a relatively high surface area, silica supported cobalt catalysts also provide low Fischer-Tropsch synthesis performance. Silica-supported cobalt catalysts are unsuitable for reaction conditions in the presence of significant amounts of water, such as those encountered in Fischer-Tropsch reaction systems. The formation of cobalt-silica compounds under such conditions is believed to cause such poor performance. To prevent or at least reduce silicate formation, the silica surface should typically be coated with an oxide promoter such as ZrO2 prior to cobalt impregnation.

Properties and Preparation of Preferred Alumina Supports The catalyst supports employed in the present invention preferably have low levels of impurities, especially low levels of sulfur (preferably less than 100 ppm sulfur), spherical morphology, about 10 to about. An average particle size of 150 mμ (more preferably about 20 to about 80 microns),
Γ-alumina having a BET surface area of about 200 to about 260 m ² / g and a porosity of about 0.5 to about 1.0 cm ³ / g after calcination.

The alumina support is preferably made from relatively high purity synthetic boehmite.
As discussed below, boehmite can be produced from aluminum alkoxides of the type obtained as a by-product in the production of synthetic fatty alcohols. Alternatively, a suitable high-purity boehmite material can be produced from an aluminum alkoxide produced by an alcohol / aluminum metal reaction process.

The aluminum alkoxide is preferably hydrolyzed to high purity, synthetic anhydrous alumina. This material is then preferably spray dried to give relatively high surface area, highly porous, spherical boehmite particles. The granular boehmite material is then preferably screened to remove fines and large particles to obtain the desired particle size range (preferably about 20 to about 80 microns). The screened material is calcined to convert the boehmite particles to γ-alumina with the desired surface area and porosity. Preferably the boehmite particles are at least 350 ° C (more preferably about 4 ° C).
It may be calcined at 00 ° C. to about 700 ° C., most preferably about 500 ° C.) for about 3 to about 24 hours (more preferably about 6 to about 16 hours, most preferably about 10 hours). The desired firing temperature is preferably achieved by heating the system at a rate of about 0.5-1.0 degrees C / min.

Suitable commercially supplied boehmite materials for forming the preferred γ-alumina support include, but are in no way limited to, CATAPAL and PURAL alumina supplied by Condea / Vista. As described below, commercial materials of this type are particularly effective when intentionally manufactured to have some target titanium "impurity" level. A product quality report for CATAPAL alumina can have various titania impurity levels of elemental titanium up to 3000 ppm by weight, as these materials are currently manufactured and sold. PURAL products, on the other hand, typically have varying titanium impurity levels up to about 600 ppm.

Doping of γ-Alumina Supports As shown below, we have unexpectedly and surprisingly discovered that the presence of a controlled amount of a dopant (preferably a titania dopant) in a γ-alumina support is present. Notably, it has been discovered that "promoter-free", significantly improves the activity of cobalt-Fischer-Tropsch catalysts on alumina. As used herein, the term "promoter-free" simply means that the catalyst is not promoted by any or near noble metals. The term does not exclude other types of accelerators (eg potassium and / or lantana). As used herein, the phrase "near precious metal" includes rhenium and, although not practical, also includes technetium for use as a promoter.

The titanium dopant should be present in the γ-alumina support in an amount of at least 500 (preferably at least 600) ppm expressed as elemental titanium. This dopant will more preferably be present in the elemental substance in the range of about 800 ppm to about 2000 ppm by weight, and most preferably in the range of about 1000 to about 2000 ppm. The titanium dopant can be added at virtually any time, but most preferably will be added prior to crystallization of boehmite.

As is well known in the art, one method of making synthetic boehmite materials is to recover aluminum alkoxides as a by-product of certain processes used for the production of synthetic fatty alcohols, such as the Ziegler process. To use. The Ziegler process typically (1) reacts high purity alumina powder with ethylene and hydrogen to produce aluminum triethyl; (2) polymerizes ethylene by contacting ethylene with the aluminum triethyl, Thus forming an aluminum alkyl; (3) oxidizing the aluminum alkyl with air to form an aluminum alkoxide; and (4) hydrolyzing the aluminum alkoxide to form an alcohol and an alumina byproduct; Including. The oxidation step of the Ziegler process is typically catalyzed by an organotitanium compound which itself converts to a titanium alkoxide. This titanium alkoxide remains with the aluminum alkoxide and is hydrolyzed at the same time as the aluminum alkoxide, thus giving rise to the originally "doped" alumina by-product with a small amount of titania.

Another method of forming synthetic boehmite uses aluminum alkoxides produced by reacting alcohols with high purity aluminum powder. Aluminum alkoxides are hydrolyzed to form alcohols, which are recycled for use in the alkoxide production process, and alumina. Since this method does not include an oxidation step, the alumina byproduct is typically titanium free. However, for the purposes of the present invention, any desired amount of titanium dopant is added to the alumina byproduct, for example, by adding the titanium alkoxide to the aluminum alkoxide, or by hydrolyzing the aluminum alkoxide and titanium alkoxide simultaneously. , Can be included. If desired, the same method can be used to add other dopants such as silica, lanthanum, barium and the like.

Traditionally, carrier manufacturers and catalyst users have simply considered that if titania was present in the alumina carrier, it was a harmless impurity. Of the synthetic boehmite products currently available on the market, some are made by the Ziegler process, others are made by the aluminum alkoxide hydrolysis described above,
Yet another is made by a combination of these methods of combining the resulting products or product precursors together. Such products are sold and used interchangeably without concern for the small amount of titanium (if any) present.

Thus, the amount of titanium present in a commercial γ-alumina support can vary from as high as 0 ppm to 3000 ppm or more. Titanium concentration can also vary significantly from batch to batch in the same commercial product.

As shown in FIG. 1, titania has a significant adverse effect on the activity of ruthenium promoter-containing cobalt on alumina catalysts employed in slurry bubble column reactors. Figure 1
Shows the activity (g-HCl / kg-cat / hr) of three ruthenium promoter-containing catalysts (Catalysts 1, 2, 3) prepared and tested in Example 1 below. Catalysts 1, 2 and 3 were identical except for that: Catalyst 3 was formed on a γ-alumina support which was known to have a titania concentration of about 7 ppm by weight expressed as titanium; Catalyst 2 was about 500 It was formed on a γ-alumina support that was found to have a titania concentration of ppm by weight; and Catalyst 3 was formed on a γ-alumina support that was known to have a titania concentration of about 1000 ppm by weight. As the titania concentration in the support increases, the activity of the catalyst, ie, the activity starting from about 1400 for catalyst 3 decreases to about 1322 for catalyst 2, and catalyst 1
To about 1195. Therefore, any artistic preference for the presence of titanium would have been that titanium should not be present in the γ-alumina support.

However, in contrast to the "precious metal promoter-containing" catalyst adverse effects on the activity of the catalyst employed in the slurry bubble column reactor, "promoter-free" cobalt on alumina in all Fischer-Tropsch reaction systems. It has been discovered that the activity of the catalyst is unexpectedly and surprisingly improved when both controlled dopants are present in the catalyst support. The "promoter-free" catalyst of the present invention has an activity that is at least close to that of the kinzoku-promoted catalyst. Moreover, the catalysts of the present invention are much less expensive to manufacture because they do not have to be promoted with noble metals. Thus, the present invention significantly reduces the cost of Fischer-Tropsch processes, especially those performed in slurry bubble columns and other three-phase reaction systems with high catalyst attrition loss.

Catalyst Preparation Although other preparation methods may be used, the catalyst component of the catalyst of the present invention is preferably a solution of an aqueous solution suitable to achieve precursor wetting of the catalyst material with the desired component loading. Added by full aqueous impregnation with composition and volume. The promoter-containing catalyst is most preferably prepared by fully aqueous co-impregnation. Examples of typical promoters include, but are not limited to, metal oxides such as oxides of Zr, La, K, and oxidation of elements from groups IA, IIA, IVA, VA and VIA. The thing is included.

Complete aqueous impregnation of cobalt into the support (with or without the desired one or more promoters) is preferably (a) calcining the alumina support in the manner described above; (b ) Impregnating the support with an aqueous solution of cobalt nitrate sufficient to achieve precursor wetting at the desired cobalt loading; (c) adding the resulting catalyst precursor under moderate agitation to about 80- Dry at 130 ° C for about 5-24 hours to remove water,
Obtaining a dry catalyst; and (d) adding the dry catalyst in air or nitrogen to about 0.5-2.
Calcining by slowly raising the temperature of the system to about 250-400 ° C. at a rate of 0 ° C./min and then holding for at least 2 hours gives the catalyst in oxide form.
Multiple impregnation / co-impregnation step (b) can be used when higher cobalt loading is desired.

Alkali (eg, potassium) and / or rare earth oxide (eg, lantana) de-promoted catalysts include, for example, potassium nitrate [KNO ₃ ], lantana nitrate [La (NO ₃ ) ₃ .
6H ₂ O] and / or other precursors can be prepared by dissolving them in the same solution containing the cobalt precursor. Alkali promoters, especially potassium, can significantly improve product selectivity and reduce methane production. Moreover, when used in suitable amounts, the alkaline promoter does not substantially reduce the catalytic activity. Lantana (
The addition of La ₂ O ₃ ) promoters can enhance the attrition resistance of the catalyst. The improved attrition resistance provided by the addition of La ₂ O ₃ does not adversely affect Fischer-Tropsch activity or Fischer-Tropsch selectivity. The preferred alkali and lanthana concentration ranges have been given previously.

Catalyst Activation In order to provide optimum performance, the catalyst is presently in a hydrogen-containing gas at a slow temperature, preferably at a rate of about 0.5-2.0 ° C./min. 250-40
It is preferably activated by raising to 0 ° C. (preferably about 350 ° C.) and holding at that desired temperature for at least 2 hours for reduction. After reduction, the catalyst is preferably cooled in flowing nitrogen.

The reducing gas preferably comprises from about 1% to 100% by volume hydrogen, with the balance (if present) being a odorous gas, typically nitrogen. The reducing gas is preferably fed at a rate of about 2-4 (preferably about 3) liters per hour per gram of catalyst. The reduction operation is preferably carried out in a fluidized bed reactor. The reduction operation is most preferably carried out under conditions (ie temperature, flow rate, hydrogen concentration, etc.) effective to ensure that a very low water vapor partial pressure is maintained during the operation.

As mentioned above, this activation procedure unexpectedly increases the activity of the "promoter-free" cobalt catalyst of the present invention. Fischer-Tropsch Reaction Process The catalyst prepared and activated according to the present invention can generally be employed in any Fischer-Tropsch synthesis process. When applicable to SBCR or continuous stirred tank reactor (CSTR) systems, the catalyst is preferably a Fischer-Tropsch wax or a synthetic fluid having properties similar to those of Fischer-Tropsch wax (eg, certificate SYNFLUID Che
It will be slurried in C ₃₀ -C ₅₀ range isoparaffin polyalphaolefin) as those available from VRON. The catalyst slurry will preferably have a catalyst concentration in the range of about 5 to about 40% by weight, based on the total weight of the slurry.

The synthesis gas feed used in the reaction process is about 0.5 to 2.
It has a CO: H2 volume ratio of 0 and preferably contains from 0 to about 60 volume% of an inert gas (ie, nitrogen, argon, or other inert gas) based on the total volume of the feed. The inert gas is preferably nitrogen.

Prior to the start of the reaction process, the activated catalyst is most preferably kept in an inert atmosphere. Prior to adding the catalyst to it, the slurry fluid is preferably purged with nitrogen to remove dissolved oxygen. The slurry composition is also transferred to the reaction system, preferably under an inert atmosphere.

A particularly preferred SBCR reaction procedure is (a) filling the SBCR with the activated catalyst slurry under an inert atmosphere, and (b) bringing the SBCR under an inert atmosphere under the desired pretreatment conditions (preferably about 220 ° C.). To about 250 ° C. and a pressure in the range of about 50 to about 500 psig), (c) replacing the inert gas with hydrogen, and allowing the system to reach the above conditions for about 2 hours to about Maintained for 20 hours (d
) Purge the system with an inert gas and adjust the temperature of the reaction system to
Lower to at least about 10 ° C below the desired operating temperature, (e) carefully replace the inert gas with the desired syngas, and (f) desired operating temperature, preferably from about 190 ° C to about 300 ° C. Heating and pressurizing to a desired operating pressure, preferably in the range of about 50 to about 500 psig;

Noble Metal-Promoted Cobalt Catalysts Noble or near-precious metal promotion has long been believed to be necessary to provide truly viable cobalt catalysts for commercial Fischer-Tropsch applications. Up until now, the accepted view in the art was that Co / Al2 containing no promoter was used.
The O3 catalyst was only 50% to less than 25% less active than the same catalyst except that it was promoted with one or more noble metals. US patent fee 5,
157,054 and other references discuss the need for ruthenium or other promoters for acceptable performance. However, the present invention unexpectedly and surprisingly provides a "promoter-free" cobalt on alumina catalyst having an activity that is at least comparable to that of a noble metal promoted cobalt catalyst.
As will be apparent to those skilled in the art, eliminating the use of noble metal promoters without significant reduction in catalytic performance can be achieved by the Fischer-Tropsch process, especially in reaction systems characterized by high commercial attrition losses. -Significantly increase the cost efficiency of the process.

As surprisingly shown in FIGS. 1 and 2, the tests set forth below demonstrate that the activated, promoter-free, cobalt-on-alumina catalyst prepared according to the present invention is a highly desirable ruthenium-promoted catalyst. It shows that it shows a level of performance comparable to. Surprisingly, these results were obtained primarily by the use of a doped gamma-alumina support. However, the very low steam partial pressure maintained during the catalyst activation procedure used, especially during the reduction procedure, also surprisingly increased the activity of the promoter-free catalyst.

The amount of dopant used is at least 60% (preferably at least 70%, most preferably at least 90%) of the activity of the otherwise identical catalyst promoted by ruthenium at a ruthenium: cobalt ratio of 1:40. ). The amount of ° C-Pantone needed to obtain the desired level of activity for any given application can thus be determined.

As mentioned above, the dopant is at least 500 ppm (preferably at least about 800 ppm to about 2000 ppm) based on the total weight of the γ-alumina support.
And is most preferably added prior to crystallization of the boehmite precursor.

Low Steam Partial Pressure With respect to the beneficial effect obtained by maintaining a very low steam partial pressure during the reduction process, the presence of steam in the activation system is dependent on the presence of some difficult-to-reduce or non-reducible cobalt- It is believed to promote the formation of alumina compounds. A temperature programmed reduction test conducted by the Applicant appears to accelerate the reduction reaction such that the presence of a noble metal promoter, such as ruthenium, may counteract the unfavorable effects of water vapor, as opposed to a catalyst containing no promoter. It revealed that.

When activating a promoter-free catalyst according to the present invention, the partial pressure of water vapor in the activation system is preferably maintained at a level or below effective to increase the activity of the catalyst. The water vapor partial pressure effective to give such results can be readily determined for any promoter-free, cobalt on alumina catalyst. The values required to obtain the desired results will vary depending on the particular catalyst selected, but it is currently preferred to maintain the water vapor partial pressure in the activation system below 0.1 atmosphere.

[0049]

【Example】

In Examples 1-4 below, certain cobalt on alumina catalysts were prepared and tested in various Fischer-Tropsch reaction systems. Prior to testing, each catalyst was reduced in pure hydrogen by gradually increasing the temperature of the catalyst in pure hydrogen at a rate of 1.0 ° C / min to about 350 ° C and maintaining this temperature for 10 hours. Hydrogen was fed at a rate of about 3 liters per hour per gram of catalyst. After reduction, the catalyst was cooled in flowing nitrogen. For the slurry bubble column reactor (SBCR) tests conducted in Examples 1-4B, the reduction operation was conducted in a fluidized bed reactor. After cooling to ambient temperature, the catalyst is weighed and leached even in SYNFLUID, then at 230 ° C. and 450 psigde using 900 sl / hr syngas and 15-20 grams of reducing catalyst.
An SBCR test was conducted. Syngas contains 60% nitrogen and 2 H2 / C
It had an O ratio. In each case, SBCR results refer to those obtained after 24 hours of operation. For the fixed bed microreactor (FBR) test, the catalyst was reduced in-situ using the same procedure as described immediately above. Prior to the introduction of syngas, the reducing catalyst was cooled 10-15 ° C below the reaction temperature. The FBR test uses 0.5-1.0 grams of catalyst and an H2 / CO ratio of 2 at atmospheric pressure and 230.
It was carried out at various conditions (i.e. low conversion) at 0 ° C. FB quoted in each case
R test results are obtained after 24 hours of operation.

Example 1 Effect of Titania Impurities on the Activity of Ru Promoter Added Catalysts in a Slurry Bubble Column Reactor (SBCR) The following ruthenium promoter added cobalt on alumina catalysts Prepared and had the same loading of cobalt and ruthenium. These catalysts differed only in the amount of titanium "impurities" contained in the γ-alumina support. All of these aluminas were manufactured by Condea / Vista.

Catalyst 1: (CA with 20 wt% cobalt and 0.5 wt% ruthenium
Ru promoter-containing cobalt catalyst on TAPAL B alumina) Boehmite type CATAPAL supplied by Condea / Vista
The B alumina was calcined at 500 ° C. for 10 hours to convert it to γ-alumina. It is then pre-sieved to 400-170 mesh (ie, particle size range greater than 38 microns and less than 88 microns) and precursor wetted (about 1.2 ml / g) at the desired Co and Ru loadings. To achieve the appropriate amount of cobalt nitrate [
_{Co (NO 3) 2 6H 2} O ] and ruthenium (III) nitrosyl nitrate [
Ru (NO) (NO ₃ ). xH ₂ O] aqueous solution. The catalyst precursor was then dried in air at 115 ° C. for 5 hours and calcined in air at 300 ° C. for 2 hours (
At a heating rate of about 1 ° C / min up to 300 ° C).

Reduction Operation Before Reaction The catalyst was reduced by heating to 350 ° C. at 1 ° C./min in a pure hydrogen flow of 300 cc / g / hr and holding for 10 hours.

Each of Catalysts 2 and 3 below was prepared similarly to Catalyst 1. Catalysts 2 and 3
The specific supports adopted for were as follows: Catalyst 2: PURAL SB carrier supplied by Condea / Vista Catalyst 3: PURAL SB1 carrier supplied by Condea / Vista Specific adopted by Catalyst 1 PURAL B carrier of about 1000 wt pp intentionally added as part of the Ziegler process prior to crystallization of boehmite.
It was determined to contain titania "impurities" in an amount of m (expressed as ppm by weight of titanium). In contrast, the specific PURAL SB employed in catalyst 2
The carrier material was prepared by the blending method and was found to contain about 500 ppm titanium. The PURAL SB1 support employed in Catalyst 3 was identical to PURAL SB except that efforts were made to prevent the addition of titanium. Elemental analysis revealed that the PURAL SB1 support contained only 7 ppm titanium. PURAL B, PURAL SB and PURAL
The crystalline properties of the SB1 support are substantially the same.

FIG. 1 shows the activity (expressed in g-HC / kg-cat / hr) exhibited by catalysts 1-3 at the end of 24 hours of operation in SBCR. Catalyst 1
A comparison of 3 illustrates the deleterious effects of titania on the activity of ruthenium promoter containing cobalt on alumina catalysts. The activity decreases significantly with increasing amount of titania in the carrier. Catalyst 3 gives an activity of about 1400 and also gives 80.5 for C ₅ ⁺ .
It then had a selectivity (% C) of 8.4 for CH ₄ . Catalyst 2 is about 1322
And had selectivities of 81.9 and 8.5 for C ₅ ⁺ and CH ₄ , respectively. Catalyst 1 gave an activity of about 1195 and was 82.2 (C ₅ ⁺ ).
And 8.2 (CH ₄ ) selectivity.

Example 2 Effect of Titania Doping on the Activity of a Promoter-Free Catalyst in a Slurry Bubble Column Reactor Catalysts 4-6 below each had catalyst 1-except that they contained no promoter. Three
Was the same as

Catalyst 4 (alumina-supported cobalt catalyst containing 20 wt% cobalt and no promoter) Boehmite type CATAPAL supplied by Condea / Vista
The B alumina was calcined at 500 ° C. for 10 hours to convert it to γ-alumina. It is then pre-sieved to 400-170 mesh (ie, particle size in the range greater than 38 microns and less than 88 microns) to achieve precursor wetting (about 1.2 ml / g) at the desired Co loading. The appropriate amount of cobalt nitrate [Co (N
O ₃₎ was impregnated with an aqueous solution of ₂ 6H ₂ O]. The catalyst precursor was then dried in air at 115 ° C. for 5 hours and calcined in air at 300 ° C. for 2 hours (up to about 300 ° C.
° C / min heating rate).

Reduction Operation Before Reaction The catalyst was reduced by heating to 350 ° C. at 1 ° C./min in a pure hydrogen flow of 300 cc / g / hr and holding for 10 hours.

Each of Catalysts 5 and 6 below was prepared in the same manner as Catalyst 4. Catalysts 5 and 6
The specific supports employed for were as follows: Catalyst 5: PURAL SB support as described above Catalyst 6: PURAL SB1 support as described above Catalysts 4-6 were tested in a slurry bubble column reactor. Their activity (expressed in g-HC / kg-cat / hr) after 24 hours of operation is also shown in FIG. In stark contrast to the results obtained with ruthenium promoter containing catalysts 1-3, the presence of titania in the γ-alumina support unexpectedly and surprisingly significantly improved the activity of the non-promoter containing catalyst. Catalyst 6 (7 ppm Ti) gave an activity of about 606 and had a selectivity (% C) of 85.6 (C ₅ ⁺ ) and 5.2 (CH ₄ ). Catalyst 5 (500 ppm Ti) gave an activity of about 775 and had a selectivity of 84.0 (C ₅ ⁺ ) and 6.2 (CH ₄ ). Catalyst 4 (1000ppm Ti) is about 10
It gave an activity of 32 and had a selectivity of 86.5 (C ₅ ⁺ ) and 6.0 (CH ₄ ). Therefore, in this SBCR test, the activity of catalyst 4 without promoter was 86% of the activity provided by catalyst 1 with ruthenium promoter. Moreover,
The selectivity provided by Catalyst 4 was significantly superior to that of the ruthenium promoter containing catalyst.

Example 3 Effect of Titania Doping on the Activity of Promoter-Free Catalysts in Fixed Bed Reactors Ruthenium promoter-containing catalysts 1 and 3 and promoter-free catalysts 4 and 6 were
A fixed bed reactor (FBR) was also tested under the above conditions (atmospheric pressure and 220 ° C. temperature). FIG. 2 again reveals a striking, unexpected, and surprising effect of titania doping on the activity of the promoter-free catalyst. Although the activity exhibited by the two ruthenium promoter containing catalysts remained relatively constant (Catalyst 1
220 and 200 g-HC / kg-cat / hr for 3 and 3, respectively,
The activity of the titanium-doped (1000 ppm) promoter-free catalyst 4 was three times higher than that of the undoped (7 ppm) promoter-free catalyst 6. Further, the activity of the catalyst 6 containing no promoter (7 ppm Ti) was only about 2% of the activity of the catalyst 3 containing promoter, while the catalyst 4 containing no promoter (1000 ppm Ti) contained the catalyst 3
The activity was about 75%.

Example 4 Effect of Titania Doping on the Performance of Ru Promoter-Containing Catalysts and Promoter-Free Catalysts in a Continuous Stirred Tank Reactor SBCR results shown in FIG. 1 are promoter-free, cobalt on alumina catalysts. Ruthenium promoter-containing catalyst 1 and non-promoter-containing catalyst 4 were tested in a continuous stirred tank reactor (CSTR) to see if they exhibited the intrinsic activity of. As mentioned above, both catalysts were supported on CATAPAL alumina containing 1000 ppm by weight of titania. In CSTR mass transfer restrictions can be neglected and true intrinsic kinetics can be measured. The performance of the two cobalt catalysts in CSTR was evaluated under the reaction conditions adopted in SBCR. SBCR and FBR
The surprising and surprising results obtained in the tests surprisingly show that the results shown in the CSTR by catalyst 1 with promoter and catalyst 4 without promoter are substantially within experimental error. Was the same. At 240 ° C. and 450 psig, ruthenium promoter-containing catalyst 1 and promoter-free catalyst 4 were 1390 and 133, respectively.
The activity was 0 (g-HC / g-cat / h).

Example 5 Temperature Programmed Reduction Studies of the Effects of Titania Doping It is well known that noble metal promoters enhance the reducibility of cobalt. The effect of titania on the reducibility of promoterless catalysts 4 and 6 was measured using temperature programmed reduction (TPR). These results were compared with the TPR results obtained for Ruthenium promoter containing catalysts 1 and 3.

In each case, the calcined catalyst was first dried for 30 minutes at 120 ° C. under a stream of argon. The TPR tests, a 5% H ₂ / Ar gas mixture was used as the reducing gas.
The reducing gas flow rate was 30 cm ³ / min. During the reduction test, the catalyst was heated to 900 ° C at a rate of 5 ° C / min. The exhaust gas was released through a cold trap (below 50 ° C) to condense and collect the water generated in the reduction reaction. The amount of H ₂ consumed by the catalyst was monitored using a thermal conductivity detector (TCD) and recorded as a function of temperature. From this data (and assuming the oxide is in the form of Co ₃ O ₄ ), 9
The total reducibility of each catalyst up to a temperature of 00 ° C was measured and expressed as the percentage of completely reduced cobalt. Table 1 shows the reduction rates of the catalysts 1, 3, 4, and 6 at 900 ° C. Table 1 also shows the low and high reduction temperature peaks exhibited by each catalyst.

[0063]

[Table 1]

As expected, both the ruthenium promoter containing catalysts were almost completely reduced (98% +) under the conditions used in the TPR experiments. Furthermore, they were reduced at lower temperatures than the non-promoter analogues. However, a comparison of the results obtained with the promoter-free catalyst shows that titania doping is again significant.
Shows that it has a beneficial effect. Like the ruthenium promoter-containing catalyst, the promoter-free catalyst with the doped support was fully (99%) reduced. However, the promoterless catalyst with no dopant was only 90% reduced.

It is possible that certain refractory cobalt-alumina compounds can be formed during the reduction, especially when the reducing system has a relatively high water vapor partial pressure, as is typical of the case. Believable. Noble metal promoters that allow cobalt reduction at lower temperatures help prevent the formation of these compounds and / or increase their reducibility. Our finding is that for promoter-free cobalt-on-alumina catalysts, the presence of a controlled amount of dopant support helps prevent the formation of cobalt-alumina compounds, thus improving the overall reducibility of the catalyst. Suggest to do something. This would explain the significant improvement in Fischer-Tropsch activity observed for promoter-free cobalt on alumina catalysts with doped supports.

Example 6 To test the effect of water vapor partial pressure during the reduction process, two different batches of the same promoter-free, 20 wt% cobalt on alumina catalyst (ie, 50 g (
Laboratory scale batches and 220 g batches) were reduced as described below and then tested in SBCR.

Test 1: 50 g (laboratory scale) batch with 100% H 2 3 L / g catalyst
Reduction was performed at 350 ° C. for 18 hours at a flow rate of not less than / hour. The SBCR test was started by charging 15 g of reduced catalyst. The reaction conditions were as follows: temperature of 220 ° C., pressure of 450 psig, total gas flow of 900 sl / hr at 60% N ₂ , and 2
H ₂ / CO ratio. The CO conversion is 13.6%, and the hydrocarbon productivity (activity) is
0.66 g HC / g cat. / Hr, and the CH ₄ selectivity was 3.2%.

Test 1: A 220 g batch of the same catalyst was reduced under the same conditions except that a hydrogen flow rate of 1.8 L / h of catalyst was used. The SBCR test was started under the charge of 15 g of reduced catalyst and carried out under the same reaction conditions as Test 1. The CO conversion is only 3.4% and the hydrocarbon productivity (activity) is just 0.17 g HC / g
cat. It was / hr.

Re-reduction of the catalyst used in trial 2 with smaller batches did not give better results. The catalyst was irreversibly damaged during the first reduction. Additional large batch reductions (ca. 0.6-1 kg) produced similarly inactive or very low activity catalysts.

These results suggest that the reduction of larger batches has a negative effect on the reducibility of the catalyst. Example 7 Following the unsuccessful, intended reduction of a large batch of promoter-free Co / Al2O3 catalyst, and the presence of a relatively high water vapor partial pressure during the initial stages of the reduction process, their low reducibility. In view of the cause of the above, it was suggested that a higher reduction temperature may give improved reducibility. Therefore, two laboratory scale batches of the same Co / Al 2 O 3 catalyst used in Example 6 (about 50
g) was reduced at 410 ° C. and 380 ° C., respectively. To test the effect of high water vapor partial pressure, the hydrogen stream used for each reduction was saturated with water vapor by passing it through a saturator at room temperature before use in the reduction system.

The SBCR test was again conducted under the same reaction conditions as described in Example 6. Despite the different reduction temperatures used, each batch had less than 1% CO conversion activity. This result shows that the high water concentration in the hydrogen stream has a significant effect on the reducibility of the catalyst, and that under such conditions the use of elevated reduction temperature does not improve the reducibility of the catalyst. Indicated. It is believed that the high water vapor partial pressure caused the formation of cobalt-alumina compounds that were very difficult or impossible to reduce. The use of higher reduction temperatures appears to actually enhance the production of such compounds, rather than enhance the reduction process.

Thus, the present invention is well adapted to carry out the objects and attain the ends and advantages mentioned, as well as those inherent therein. While this invention has been described with particularity, it will be apparent that many modifications can be made without departing from the spirit and scope of this disclosure. It is understood that the invention is not limited to the embodiments shown here for illustrative purposes.

[Brief description of drawings]

FIG. 1 is a graph comparing the effect of titanium dopant concentration on the activity of ruthenium promoter-containing and “promoter-free” catalysts for the SBCR-implemented Fischer-Tropsch synthesis process. give. Each test included 15-25 grams of catalyst that was sieved outside the SBCR to 400-150 mesh, calcined, and then reduced / activated. Each Fischer-Tropsch reaction test was conducted at 450 psig and 2 with a synthesis gas flow rate of 15 liters per minute.
Performed at 30 ° C. The syngas was diluted with 60% nitrogen and H ₂ : CO 2
Had a ratio.

FIG. 2 shows a comparison of the effect of titanium dopant concentration on the activity of ruthenium promoter-containing and “promoter-free” catalysts for Fischer-Tropsch synthesis carried out in a fixed bed reactor. Give a graph. In each case, each Fischer-Tropsch reaction has a pressure of 1 atm, a temperature of 220 ° C. and a H _{2 of 2} :
Performed at CO ratio.

─────────────────────────────────────────────────── ─── Continued front page    (81) Designated countries EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, I T, LU, MC, NL, PT, SE), OA (BF, BJ , CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, GM, K E, LS, MW, SD, SL, SZ, UG, ZW), E A (AM, AZ, BY, KG, KZ, MD, RU, TJ , TM), AL, AM, AT, AU, AZ, BA, BB , BG, BR, BY, CA, CH, CN, CU, CZ, DE, DK, EE, ES, FI, GB, GD, GE, G H, GM, HR, HU, ID, IL, IN, IS, JP , KE, KG, KP, KR, KZ, LC, LK, LR, LS, LT, LU, LV, MD, MG, MK, MN, M W, MX, NO, NZ, PL, PT, RO, RU, SD , SE, SG, SI, SK, SL, TJ, TM, TR, TT, UA, UG, UZ, VN, YU, ZW (72) Inventor Goodwin, James G             Pennsylvania, USA 16066,             Cranberry Township, Raglan             De Drive 219 F-term (reference) 4G069 AA03 AA08 BA01A BA01B                       BC01C BC03A BC41A BC50A                       BC50B BC67A BC67B BC70A                       BC70B CC23 DA06 DA08                       EA02Y EA04Y EB18Y EC03Y                       EC07Y FA01 FB44 FC02                       FC08                 4H029 CA00 DA00

Claims (39)

[Claims] 1. A cobalt catalyst for hydrocarbon synthesis, the cobalt catalyst comprising cobalt supported on a γ-alumina support: the cobalt catalyst is not promoted by any noble metal and Co., characterized in that it is also not promoted by the noble metals of the above; and that the γ-alumina support contains a dopant in an amount effective to increase the activity of the cobalt catalyst for the synthesis of the hydrocarbon. catalyst. 2. The cobalt catalyst of claim 1, wherein the dopant is a titanium dopant. 3. The amount of the titanium dopant is 1: 4 with respect to the cobalt catalyst.
An amount effective to make it at least 60% more active than a promoted catalyst that is identical to the cobalt catalyst except that it is promoted by ruthenium at a ruthenium: cobalt weight ratio of 0. The cobalt catalyst according to claim 2. 4. The cobalt catalyst of claim 3, wherein the amount of titanium dopant is an amount effective to cause the cobalt catalyst to be at least 70% more active as compared to the promoted catalyst. 5. The cobalt catalyst of claim 3 wherein the amount of titanium dopant is an amount effective to cause the cobalt catalyst to be at least 80% more active as compared to the promoted catalyst. 6. A cobalt catalyst according to claim 1, wherein the amount of titanium dopant is at least 500 ppm by weight, expressed as elemental titanium, of the total weight of the γ-alumina support. 7. The cobalt catalyst of claim 2 wherein the amount of titanium dopant, expressed as elemental titanium, is in the range of about 800 to about 2000 ppm by weight of the total weight of the γ-alumina support. 8. A cobalt catalyst according to claim 2 wherein the amount of titanium dopant is about 1000 ppm by weight of the total weight of the γ-alumina support, expressed in elemental titanium. 9. The cobalt catalyst of claim 2 wherein the cobalt catalyst is an activated catalyst that has been reduced in the presence of hydrogen and at a steam partial pressure effective to increase the activity of the cobalt catalyst. 10. The steam partial pressure is in the range of 0 to about 0.1 atm.
Cobalt catalyst. 11. The cobalt catalyst of claim 2 wherein the cobalt catalyst is promoted with at least one of potassium and lanthana. 12. The γ-alumina support is formed from synthetic boehmite; and the dopant is added to the γ prior to crystallization of the synthetic boehmite.
A cobalt catalyst according to claim 1, characterized in that it is added to an alumina support. 13. A hydrocarbon synthesis method comprising the step of reacting syngas in the presence of a cobalt catalyst, wherein the cobalt catalyst comprises cobalt supported on a γ-alumina support; Not promoted by noble metals and not promoted by any nearby noble metals; and the γ-alumina support is in an amount effective to increase the activity of the cobalt catalyst for the hydrocarbon synthesis. Including a dopant; The method above. 14. The method of claim 13 wherein said dopant is a titanium dopant. 15. The amount of the titanium dopant is such that the cobalt catalyst is 1:
To have at least 60% higher activity for the hydrocarbon synthesis compared to a promoted catalyst that is identical to the cobalt catalyst except that it is promoted by ruthenium at a ruthenium: cobalt weight ratio of 40. 15. The method of claim 14, which is an effective amount. 16. The method of claim 15, wherein the amount of titanium dopant is an amount effective to cause the cobalt catalyst to be at least 70% more active as compared to the promoted catalyst. 17. The method of claim 15, wherein the amount of titanium dopant is an amount effective to cause the cobalt catalyst to be at least 80% more active as compared to the promoted catalyst. 18. The method of claim 14, wherein the amount of titanium dopant is at least 500 ppm by weight of the total weight of the γ-alumina support, expressed as elemental titanium. 19. The amount of titanium dopant, expressed in elemental titanium,
15. The method of claim 14, which is in the range of about 800 to about 2000 ppm by weight of the total weight of the [gamma] -alumina carrier. 20. The method of claim 14, wherein the amount of titanium dopant is about 1000 ppm by weight of total elemental titanium, expressed as elemental titanium. 21. A step of activating the cobalt catalyst prior to the reaction step by reducing the cobalt catalyst in the presence of hydrogen and at a steam partial pressure effective to increase the activity of the cobalt catalyst. 15. The method of claim 14 including. 22. The water vapor partial pressure is in the range of 0 to about 0.1 atm.
Method 2. 23. The reaction step is carried out in a slurry bubble column reactor.
the method of. 24. The method of claim 13, wherein the hydrocarbon synthesis is a Fischer-Tropsch process. 25. The gamma-alumina support is formed from synthetic boehmite; and the dopant is added to the gamma prior to crystallization of the synthetic boehmite.
A method according to claim 13, characterized in that it is added to an alumina support. 26. A cobalt catalyst for the synthesis of hydrocarbons containing cobalt supported on a γ-alumina support, wherein the cobalt catalyst is not promoted by any precious metal and by any nearby precious metal. Unpromoted; and the cobalt catalyst was reduced in the presence of hydrogen at a steam partial pressure effective to increase the activity of the cobalt catalyst for the synthesis of hydrocarbons; catalyst. 27. The water vapor partial pressure is in the range of 0 to about 0.1 atmosphere.
6 cobalt catalyst. 28. The cobalt catalyst of claim 26, wherein the γ-alumina support comprises titanium dopant, expressed in elemental titanium, in an amount of at least 500 ppm by weight of the total weight of the γ-alumina support. 29. The cobalt catalyst of claim 28, wherein the amount of titanium dopant, expressed as elemental titanium, is in the range of about 800 to about 2000 ppm by weight of the total weight of the γ-alumina support. 30. The gamma-alumina support is formed from synthetic boehmite; and the dopant is added to the gamma prior to crystallization of the synthetic boehmite.
A cobalt catalyst according to claim 28, characterized in that it is added to an alumina support. 31. A method of synthesizing a hydrocarbon; (a) increasing the activity of a cobalt catalyst containing cobalt supported on a γ-alumina support in the presence of hydrogen and for synthesizing the hydrocarbon catalyst. With a partial pressure of water vapor effective to :; and (b) reacting syngas in the presence of the cobalt catalyst; wherein the cobalt catalyst is not promoted by any noble metal and The above method characterized in that it is not promoted even by a noble metal. 32. Step (a) is carried out in a fixed bed vessel;                   Step (b) is carried out in a slurry bubble column reactor; 32. The method of claim 31. 33. The steam partial pressure is in the range of 0 to about 0.1 atm.
Method 1. 34. The method of claim 31, wherein the gamma-alumina support comprises titanium dopant, expressed in elemental titanium, in an amount of at least 500 ppm by weight of the total weight of the gamma-alumina support. 35. The method of claim 34, wherein the amount of titanium dopant, expressed as elemental titanium, is in the range of about 800 to about 2000 ppm by weight of the total weight of the γ-alumina support. 36. The method of claim 31, wherein the hydrocarbon synthesis is a Fischer-Tropsch process. 37. A method of improving the activity of a cobalt catalyst for hydrocarbon synthesis, wherein the cobalt catalyst has an alumina support and the cobalt catalyst is not promoted by any noble metal, and Not promoted by any near-noble metal, the method comprises the step of including a titanium dopant in the carrier, expressed as elemental titanium, in an amount of at least 500 ppm of the total weight of the alumina carrier. The above method. 38. The method of claim 37, wherein the amount of titanium dopant expressed in elemental titanium is in the range of about 800 to about 2000 ppm of the total weight of the alumina support. 39. The method of claim 37, further comprising the step of reducing the cobalt catalyst in hydrogen at a water vapor partial pressure of 0 to about 0.1 atmosphere.