JP3118244B2 - Method for producing surface impregnated dispersed cobalt metal catalyst - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a process for producing a cobalt catalyst in which a metal is impregnated and dispersed as a thin film or coating on the periphery or outer surface of a particulate support or support, particularly a titania support or support.

BACKGROUND OF THE INVENTION Granular catalysts are commonly used in chemical, petroleum and petrochemical processes to chemically convert or convert various gas and liquid feeds to more desirable products. Such catalysts are prepared by dispersing one or more catalytically active metals, or compounds thereof, on a particulate carrier or support. According to common knowledge, the one or more catalytically active metals are generally dispersed as uniformly as possible throughout the particles, providing uniformity of the catalytically active sites outward from the center of the particles.

Fischer-Tropsch synthesis, a process for producing hydrocarbons from carbon monoxide and hydrogen (syngas), is commercially practiced in several parts of the world. This method may be more widely accepted in the United States, if appropriate modifications are made to existing technology. Early Fischer-Tropsch catalysts consisted largely of non-noble metals dispersed throughout a porous inorganic oxide support. In the Fischer-Tropsch reaction, Group VIII non-precious metals, iron, cobalt and nickel are widely used,
And these metals are promoted with various other metals and are supported in various ways on various supports, mainly alumina. However, most commercial experience is based on cobalt and iron catalysts. First commercial fisher
Although the Tropsch operation utilized a cobalt catalyst, later, more active iron catalysts were also commercialized. Cobalt and iron catalysts were made by blending the metal throughout the inorganic oxide. However, early cobalt catalysts generally had low activity requiring the use of a multi-step process and low synthesis gas throughput. On the other hand, iron catalysts produce too much carbon dioxide from synthesis gas and too little carbon monoxide is converted to hydrocarbons.

OBJECTS OF THE INVENTION Accordingly, a first object of the present invention is to provide a catalytically effective amount of cobalt, or cobalt and one or more additional metals, on the periphery or outer surface of a particulate inorganic oxide support, particularly a particulate titania or titanium-containing support. To provide a further improvement in the production of high-productivity Fischer-Tropsch cobalt catalysts by the impregnation method by spraying with water.

Another object of the present invention is to spray, impregnate and disperse cobalt, or cobalt and one or more additional metals, on the surface of the granular carrier particles while heating and maintaining the granular carrier particles in a fluidized state. It is an object of the present invention to provide a spray coating method characterized by the first object.

One particular object of the present invention is a particulate inorganic oxide support,
A compound containing cobalt, or a compound containing cobalt and one or more promoter metals, particularly on the periphery of the particulate titania or titanium-containing carrier, that is, on the outer surface, while keeping the particulate carrier in a fluidized state under heating conditions. To provide a cobalt catalyst useful for Fischer-Tropsch synthesis and a method for producing a promoted cobalt catalyst by using an impregnation method by spray coating.

Another more specific object of the present invention is to spray coat and impregnate cobalt, or cobalt and one or more additional cobalt modifiers or promoter metals, on a heat fluidized granular titania or titania-containing support. It is an object of the present invention to provide a novel process, especially where the titania or titania component has a high rutile: anatase ratio.

These and other objects of the invention are to provide the particulate porous inorganic oxide carrier particles at a temperature of about 50 ° C or higher, preferably from about 50 to about 100 ° C.
The carrier particles in the fluidized bed are contacted and contacted with a liquid dispersion, suitably a suspension or solution, of the one or more compounds of the metal, while maintaining a temperature of from about 70 ° C., more preferably from about 70 to about 90 ° C. By impregnation, a catalytically active layer or film is formed on the peripheral or outer surface of the granular porous inorganic oxide support, on the periphery or on the outer surface, of cobalt effective as a catalyst in a Fischer-Tropsch synthesis reaction, or cobalt and one or more additional metals. The invention is embodied in a method for producing a catalyst coated as a substrate. Preferred inorganic oxide supports are alumina, silica, alumina-silica and titania, among which titania or titania-containing supports, especially rutile titania supports,
Alternatively, the titania or titania component is at least about 3:
Carriers having a rutile: anatase weight ratio of 2 are most preferred. The catalytically active surface layer or membrane has an average thickness of about 20 to
About 250 μm, preferably in the range of about 40 to about 150 μm,
The cobalt content, expressed as the weight of metallic cobalt per unit bulk volume of the catalyst, ranges from about 0.01 to about 0.15 g / cc catalyst, preferably from about 0.03 to about 0.09 g / cc catalyst.

To improve the activity and regeneration ability of the catalyst, rhenium,
Metals such as zirconium, hafnium, cerium, thorium and Raun or compounds of these metals can be added to the cobalt. Thus, the thin catalytically active layer or film formed on the surface of the support particles, in particular titania or titania-containing support particles, may contain, in addition to the cobalt of the catalytically active layer, rhenium, zirconium, hafnium, cerium, thorium and uranium, or these. It may contain one or more of each other, or mixtures of these with other metals, or these compounds. Thus,
Preferred thin catalytically active layers or membranes supported on a support, especially a titania or titania-containing support, are cobalt rhenium, cobalt zirconium, cobalt hafnium,
Cobalt-cerium, cobalt-thorium and cobalt-round are included in the presence or absence of other metals or compounds thereof.

Spraying the support particles with a suspension or solution containing a compound of cobalt or one or more compounds of cobalt and one or more additional metals, which is fluidized in the bed and effective as a catalyst in the Fischer-Tropsch synthesis reaction. I do. The temperature of the bed during spraying should be above 50 ° C, preferably from about 50 to about 100 ° C, more preferably from about 70 to about 90 ° C. Suitably, the carrier particles are fluidized with a gas, preferably air, and the fluidized bed of carrier particles is sprayed with the suspension or solution through one or more nozzles. Important and novel features of the method of the present invention are the temperature and flow rate of air, one or more metals,
Operating within the specified range of flow rates of the suspension or solution from one or more nozzles and one or more nozzles into the bed results in a very high particle drying capacity during spraying. The temperature of the bed during spraying, or the spraying, in the production of one or more metal films or coatings of the required uniform thickness on the granular particles, for example the coating of a cobalt metal film on a granular titania support. The temperature should be maintained above about 50 ° C, preferably between about 50 and about 100 ° C, more preferably between about 70 and about 90 ° C. Also, the ratio of solution feed rate to fluidizing gas or air velocity is less than about 21.2 g solution / m ³ air (0.6 g solution / ft ³ air), preferably about 3.53 to about 21.2 g / m ³ (about 0.1 to 0.6g /
ft ³ ), more preferably about 10.6 to about 17.7 g / m ³ (about 0.3 to about
0.5 g / ft ³ ). By employing these parameters together, a high metal recovery is obtained, the drying capacity is controlled and the average thickness is from about 20 to about 250
μm, preferably from about 40 to about 150 μm, and the content of one or more such metals, expressed as the weight of metal-like metal per unit bulk volume of the catalyst, is from about 0.01 to about 0.15 g / m
A catalyst is produced that ranges from cc, preferably from about 0.03 to about 0.09 g / cc catalyst. When the temperature of the fluidizing gas is on the high temperature side, the solution-to-gas ratio of the higher side of the specified range is preferable, and conversely, when the temperature of the fluidizing gas is on the low temperature side, it is specified. The solution to gas ratio on the lower side of the range is preferred. The content of one or more metals in the solution and the porosity of the carrier will also, to some extent, affect the thickness of one or more of the metals under a given set of spraying conditions. About cobalt,
For example, when operating within the specified preferred conditions,
The thickness of the cobalt film ranges from about 100 to about 250 μm for a volumetric cobalt content of about 6 g / 100 cc. Generally, the concentration of one or more metal compounds in the suspension or solution will be about 5% or more, preferably 10% or more. Preferably, a solution is used, and the solution can be saturated or supersaturated with one or more metal compounds. The optimum concentration is probably best determined by one or more particular compounds used. Low concentrations require longer spray times, while higher concentrations shorten spray times. In order to obtain the required content of one or more metals for the film thickness, a balance between the specific solution concentration and the required spray time is required.

Although several types of bed fluidizers are described in the literature, certain types and sizes of fluidized bed devices themselves affect the depth of impregnation of one or more metals below the peripheral surface of the particulate support. Does not seem to have. Known devices include, for example, fluidized bed granulators / dryers fitted with nozzles entering from above or below the bed, rotary granulators, and Wurster columns. Such equipment is available from Glatt Air Tecnics, Inc. of Ramsey, NJ, USA.
Chniques, Inc.) as a one-top sprayer (Versa-Glatt model) and a 20-top sprayer, model GPCG-5, and the Coatin Press of Verona, Wisconsin, USA.
g Place, Inc.) as a 20 bottom sprayer. The top inlet nozzle appears to have less particle breakage. Typically, in the operation of these devices, the air flow rate is adjusted to the required rate to properly fluidize the carrier particles, and then the metal solution addition rate is adjusted to the air flow rate. .

Cobalt titania catalysts are particularly preferred. cobalt·
The titania catalyst is ASTM D3720-78, the ratio of anatase to rutile in titanium dioxide pigment in titanium dioxide pigment by using X-ray diffraction.
Pigments by Use of X-Ray Diffraction) as determined by the standard test method, titania having a rutile: anatase weight ratio of at least about 3: 2, or cobalt on a titania-containing carrier or support. A catalyst in which a promoter is dispersed as a thin catalytically active film. Generally, the cobalt titania catalyst is a catalyst wherein the titania has a rutile: anatase ratio in the range of at least 3: 2 to 100: 1 or more, more preferably about 4: 1 to about 100: 1 or more. When each of rhenium, zirconium, hafnium, cerium, thorium or uranium metal is added to cobalt as a promoter to form a thin catalytically active film, the weight ratio of cobalt: metal promoter is about 30: 1 to about 30: 1. 2: 1, preferably about 20: 1 to about
Metal is added to cobalt at a concentration sufficient to be in the 5: 1 range. Rhenium and hafnium are the preferred promoter metals, with rhenium being more effective in promoting improved activity retention on an absolute basis and hafnium being more effective on a price-effectiveness basis. These catalyst compositions have been found to have low methane selectivity, produce products that are primarily C ₁₀₊ linear paraffins and olefins, and have very low oxygenation products. These catalysts also provide high activity, high selectivity and high activity retention in the conversion of carbon monoxide and hydrogen to distillate fuels.

After the end of spraying, the impregnated metal compound must be decomposed into the corresponding metal oxide. Preferably, one or more metal components, for example cobalt, in order to convert the cobalt to C ₀₃ O _4, at a temperature sufficient to oxidize, contacting the catalyst with oxygen, air or other oxygen-containing gas . Approximately 150 ° C to convert metals, especially cobalt, to oxides
Above, preferably a temperature of about 200 ° C. or higher is sufficient. About 5
Temperatures above 00 ° C should be avoided. Suitably 1
The decomposition of one or more metal compounds is performed at a temperature in the range of about 150 to about 300C. This decomposition step can be carried out in a fluidized bed apparatus or in an external oven or calciner.

The cobalt catalysts prepared by the process of the present invention have proven particularly useful for the production of liquid hydrocarbons from synthesis gas with high productivity and have low methane production. These cobalt catalysts contain essentially all of the active metal, especially cobalt, on the outer peripheral surface of the carrier particle, with the metal being substantially excluded from the inner surface of the particle. The high metal content in the thin edges or shells on the outer surface of the particles maximizes the reaction between hydrogen and carbon monoxide at the surface of the catalyst particles. This avoids the usual diffusion limitations of most prior art catalysts, and the catalysts of the present invention behave more ideally, approaching the behavior of powdery catalysts without diffusion limitations. However, unlike the use of powdered catalysts, the reactant flow through the catalyst bed is virtually unhindered due to the large size of the catalyst. Large-scale production of catalysts of this type, which is extremely difficult, if not impossible at all with the known techniques, is easily achieved by the process according to the invention.

At a practice of synthesis gas reaction, the total pressure of the reaction mixture of CO and H ₂ are generally about 5.624kg / cm ² gauge pressure (80 psig) or more, preferably coercive above about 9.844kg / cm ² gauge pressure (140 psig) Dripping. In order to increase the concentration of _{C10 +} hydrocarbons in the product, generally it will exceed about 0.5: 1, preferably about 1.
It is desirable to use a carbon monoxide and hydrogen molar ratio of H ₂ : CO of 7: 1 or more. Suitably, H _2: CO molar ratio of about 0.5: 1
Carbon monoxide and hydrogen are used in a molar ratio of H ₂ : CO in the range of about 1.7: 1 to about 2.5: 1, preferably in the range of about 4: 1. Generally, from about 100 to about 5000 V / Hr / V, preferably from about 300 to about 1500 V /, measured as the standard volume of a gas mixture of carbon monoxide and hydrogen per hour per unit volume of catalyst (0 ° C., 1 atmosphere). Hr
The reaction takes place at gas hourly space velocities in the range of / V. The reaction is carried out at a temperature ranging from about 160 to about 290C, preferably from about 190 to about 260C. Pressure is preferably from about 5.624 to about 42.18 kg / c
m ² gauge pressure (about 80 to about 600 psig), more preferably from about 9.8
It ranges from 44 to about 28.12 kg / cm ² gauge pressure (about 140 to about 400 psig). The product generally and preferably comprises at least 60%, more preferably at least 75%, _C10 + liquid hydrocarbons having a boiling point of at least 320 ° F.

The present invention is described by reference to the following examples and descriptions, which show comparative data that illustrate the more salient features of the present invention.
It will be more fully understood. Unless noted otherwise,
All parts are by weight.

Examples 1-10 A set of supports for use in the preparation of the catalyst were obtained from reliable commercial sources or were prepared from granular titania alumina (9
Manufactured from 6.5% Ti / 3.5% Al ₂ O ₃ ), silica, alumina in both extrudate and spherical form. The composition of the carrier, its physical size and shape, and some physical properties, namely surface area (SA) in m ² / g (BET), pore volume (PV) and porosity measured by mercury injection The results are shown in Table 1.

Table 2 shows the catalysts prepared from these supports. The supports used in the preparation of the catalyst are indicated by the support numbers in Table 1.

An aqueous solution of cobalt nitrate (11-13% by weight Co) and perrhenic acid (1-1.3% by weight Re) was used to make a set of 15 catalysts. These catalysts are available in fluidized bed sprayers, 1 and 20 top sprayers, respectively, from Glatt Aia Techniques, Inc., and 20 from Coating Place, Inc. Manufactured individually in a bottom sprayer. The catalyst was calcined as shown in Table 2. The second table, loaded weight of the fluidized bed nebulizer solution rate (g / min), fluidizing air velocity (ft ³ / min (CFM), the solution: air ratio (g / ft ^3), the average in the spray Bed temperature, calcination method,% by weight of Co-Re on final catalyst: average depth from outer surface, ie Co- on outer surface of carrier particles
Re thickness, ie electron probe analyzer (JEOL C
The RIM thickness measured with ompany, Model No. JXA-50A) is also shown. The Co-Re surface layer thickness, or RIM, is a measure of the success or failure of a given catalyst preparation. The metal distribution was found to be non-uniform throughout this depth, and the concentration often decreased with increasing distance from the peripheral surface of the particles. However, measurements taken within the particles and on a particle-by-particle basis generally showed good uniformity, especially for the successful catalyst preparations Nos. 1-10 according to the present invention. In addition to the average RIM thickness, metal recovery was also an important criterion of success, with metal recovery exceeding 90% by weight except for Example 12.

The following conclusions can be drawn from the preparations described in Table 2. That is, Preparations Nos. 1-4a show that there is a strong relationship between spray temperature and RIM thickness when other conditions are relatively constant. Over a range of 50-100 ° C., the higher the temperature, the thinner the RIM. Note that Production Nos. 1-3 were sprayed at a low solution: air ratio.

Preparations 4a and 4b show that the RIM thickness depends to some extent on the final firing step. The molten nitrate moves further into the support during heating before decomposing into oxides. This movement of the metal towards the center of the particles can be minimized by rapid heating, and atomizers are the best way to do this.
An alternative is to use a low solution: air ratio during spraying. Excessive drying of this can help minimize the tendency of the RIM to migrate later during firing. A solution: air ratio of 0.56 is at the high end of the acceptable range. When a small portion was removed from the atomizer immediately after spraying and then fired in a tube unit, the RIM increased significantly.

Comparison of Preparation No. 5 with Preparation No. 2 shows that the RIM thickness is a function of the cobalt content. The less cobalt sprayed onto the carrier under certain spray conditions, the thinner the RIM.

Preparation No. 6 shows that exceptionally thin RIM can be made with high metal content. In this case, Preparation No. 5 was simply returned to the atomizer for another impregnation after firing. A very thin RIM was obtained compared to the single impregnation preparation No. 2.

Preparations Nos. 7 and 8 show that the RIM thickness is a function of the porosity of the carrier. When the carrier has a high pore volume, the RI
M is thinner (Production No. 7 for Production No. 4a).

Preparations No. 9 and No. 10 show success on silica and alumina supports.

Preparations Nos. 11 and 12 show the adverse effects of operating outside the preferred temperature range. Preparation No. 11 shows that spraying below 50 ° C. does not give a RIM despite a low solution: air ratio. Also, only 2.8% of cobalt was precipitated. Preparation No. 12
Spraying at 110 ° C gives a thin RIM, but does not
It shows that only 60% is finally deposited on the catalyst. The balance of cobalt and expensive rhenium was carried off from the top as fines. It appears that "spray drying" of the solution and decomposition of the nitrate occurred before the solution reached the carrier.

Top Nos. 13 and 14 indicate that good RIM is not obtained when using a high solution: air ratio.

In addition, a series of Fischer-Tropsch experiments were performed with catalysts successfully manufactured in fluid bed technology to demonstrate the utility of these RIM catalysts. All were successful and the data obtained agreed well with the predicted performance based on the cobalt content and RIM thickness of each catalyst preparation. The results obtained for catalyst preparation 4a can be considered illustrative. Preparation No. 4a was thus used for the conversion of synthesis gas to heavy hydrocarbons. After reducing a portion of the catalyst at 450 ° C. for 1 hour, for a feed containing 65% H ₂ /31% CO / 4% Ne, 200 ° C., 19.684 kg / cm ² gauge (280 psig), GHSV =
The reaction was performed at 1,000. After 20 hours of operation, the CO conversion was 79%. Reacted CO 1 product selectivity represented by the number of moles of CO were converted to product per mole of 6.0% CH _4, it was 0.4% CO ₂ and 93.4% C _2+.

Obviously, various changes and modifications can be made without departing from the spirit and scope of the invention.

────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Kennis Lloyd Lilly Beitung Rouge Rodney Drive, Louisiana, USA 1289 (56) References JP-A-63-147545 (JP, A) (58) Fields investigated (Int. Cl. . ^7, DB name) B01J 21/00 - 37/36

Claims (13)

(57) [Claims] 1. A catalytically effective amount of cobalt is dispersed as a layer on the peripheral outer surface of a particulate porous inorganic oxide support to produce a catalyst useful for the conversion of synthesis gas to hydrocarbons, and A method for preparing a catalyst, comprising contacting said carrier particles with a spray comprising one or more decomposable compounds of said metal, wherein the bed of said carrier particles is brought into contact with a gas at a temperature in the range of 50-100 ° C by 50-50 ° C. The bed of heated carrier particles is maintained in a fluidized state at a temperature in the range of 100 ° C. and the heated bed of carrier particles is a liquid in which one or more compounds of cobalt are dispersed, the ratio of the flow rate of the liquid to the flow rate of the fluidizing gas. Is sprayed at a flow rate sufficient to be less than 21.2 g liquid / m ³ fluidizing gas (0.6 g liquid / ft ³ fluidizing gas), the average thickness is in the range of 20-250 μm, and Content is in the range of 0.01 to 0.15 g / cc, calculated as metal-like metal per unit packed bulk volume of catalyst A production method comprising forming a surface layer of the metal on the particles. 2. A liquid flow velocity: fluidizing gas velocity velocity ratio of 10.6.
^{~17.7g / m 3 (0.3~0.5g / ft} 3) The process according to claim 1, wherein the range of. 3. The method according to claim 1, wherein the one or more decomposable metal compounds comprises a compound containing cobalt, and a compound selected from the group consisting of rhenium, hafnium, zirconium, cerium, thorium and uranium, and wherein the one or more cobalt compounds are selected from the group consisting of: The method according to claim 1, wherein said additional metal is dispersed as a surface layer on said carrier. 4. The catalyst according to claim 1, wherein the catalytically active surface layer has an average thickness in the range of from 40 to 150 μm and a cobalt content of from 0.03 to 0.09 g / m.
2. The method according to claim 1, wherein the range is cc. 5. The process according to claim 1, wherein said carrier comprises alumina, silica, silica-alumina, titania or a mixture of alumina, silica or titania. 6. The method according to claim 5, wherein said carrier comprises titania. 7. The method of claim 6, wherein the titania has a rutile: anatase weight ratio of at least 3: 2. 8. The method of claim 7 wherein the titania has a rutile: anatase weight ratio in the range of at least 3: 2 to 100: 1 and greater. 9. The ratio of the flow rate of the liquid to the flow rate of the fluidizing gas containing the dispersed metal compound is 10.6-17.7 g / m ³ (0.3-0.5 g / ft).
^{3. The} method according to claim 1, wherein the method falls within the range of ³ ). 10. The method according to claim 1, wherein the liquid in which the one or more compounds of cobalt are dispersed is water. 11. The method according to claim 1, wherein the fluidizing gas is air. 12. The method according to claim 1, wherein the temperature of the fluidizing gas ranges from 70 to 90 ° C. 13. The method according to claim 12, wherein the fluidizing gas is air.