Extruded titania-based material comprising zirconium oxide

Abstract

Porous, extruded titania-based materials further comprising zirconium oxide and/or prepared using ammonium zirconium carbonate, Fischer-tropsch catalysts comprising them, uses of the foregoing, processes for making and using the same and products obtained from such processes.

Claims

1. A Fischer-Tropsch synthesis catalyst comprising a porous, extruded titania-based material comprising zirconium oxide, and further comprising at least one metal selected from a group consisting of cobalt, iron, nickel, ruthenium and rhodium.

2. A Fischer-Tropsch synthesis catalyst according to claim 1, wherein the porous, extruded titania-based material comprises mesopores and macropores.

3. A Fischer-Tropsch synthesis catalyst according to claim 2, further comprising one or more promoters.

4. A Fischer-Tropsch synthesis catalyst according to claim 3, therein the one or more promoters is selected from a group consisting of rhenium, ruthenium, platinum, palladium, molybdenum, tungsten, boron, zirconium, gallium, thorium, manganese, lanthanum, cerium, and mixtures thereof.

5. A Fischer-Tropsch synthesis catalyst according to claim 2, further comprising cobalt.

6. A Fischer-Tropsch synthesis catalyst according to claim 5, wherein the mesopores have a pore diameter of 15 to 45 nm.

7. A Fischer-Tropsch synthesis catalyst according to claim 5, wherein the macropores have a pore diameter of 60 to 1000 nm.

8. A Fischer-Tropsch synthesis catalyst according to claim 2, wherein the porous, extruded titania-based material has a crush strength of greater than 3.0 lbf.

9. A Fischer-Tropsch synthesis catalyst according to claim 2, wherein the porous, extruded titania-based material is in the form of symmetrical cylinders, dilobes, trilobes, quadralobes or hollow cylinders.

10. A Fischer-Tropsch synthesis catalyst according to claim 2, wherein the mesopores have a pore diameter of 15 to 45 nm.

11. A Fischer-Tropsch synthesis catalyst according to claim 2, wherein the macropores have a pore diameter of 60 to 1000 nm.

12. A Fischer-Tropsch synthesis catalyst according to claim 2, wherein the total pore volume is at least 0.30 ml/g.

13. A Fischer-Tropsch synthesis catalyst according to claim 2, wherein the BET surface area is at least 30 m.sup.2/g.

14. A process for the preparation of a Fischer-Tropsch synthesis catalyst according to claim 2, said process comprising: a) mixing titanium dioxide and one or more porogens to form a homogeneous mixture; b) adding ammonium zirconium carbonate and a solution of one or more thermally decomposable cobalt, iron, nickel, ruthenium or rhodium compound to the mixture, and mixing to form a homogeneous paste; c) extruding the paste to form an extrudate; d) drying and/or calcining the extrudate at a temperature sufficient to convert at least a portion of the ammonium zirconium carbonate to zirconium oxide, to decompose the one or more porogens and to convert the at least one thermally decomposable cobalt, iron, nickel, ruthenium or rhodium compound to an oxide thereof, or to the metal form; and, where an oxide is formed, optionally e) heating the dried and/or calcined extrudate under reducing conditions to convert the at least one cobalt, iron, nickel, ruthenium or rhodium oxide to the metal form.

15. A process for the preparation of Fischer-Tropsch synthesis catalyst according to claim 1, said process comprising: a) mixing titanium dioxide, ammonium zirconium carbonate and a solution of at least one thermally decomposable cobalt, iron, nickel, ruthenium or rhodium compound, to form a homogeneous paste; b) extruding the paste to form an extrudate; c) drying and/or calcining the extrudate at a temperature sufficient to convert at least a portion of the ammonium zirconium carbonate to zirconium oxide, and to convert the at least one thermally decomposable cobalt, iron, nickel, ruthenium or rhodium compound to an oxide thereof, or to the metal form; and, where an oxide is formed, optionally d) heating the dried and/or calcined extrudate under reducing conditions to convert the at least one cobalt, iron, nickel, ruthenium or rhodium oxide to the metal form.

16. A Fisher-Tropsch synthesis catalyst prepared by a process according to claim 15, preferably having a crush strength of greater than 5.0 lbf.

17. A process for the preparation of a Fischer-Tropsch synthesis catalyst according to claim 1, said process comprising: a) impregnating a porous, extruded titania-based material, extruded titania-based material with a solution of at least one thermally decomposable cobalt, iron, nickel, ruthenium or rhodium compound; b) drying and/or calcining the impregnated porous, extruded titania-based material, extruded titania-based material at a temperature sufficient to convert the at least one thermally decomposable cobalt, iron, nickel, ruthenium or rhodium compound to an oxide thereof, or to the metal form; and, where an oxide is formed, optionally c) heating the dried and/or calcined porous extruded titania-based material under reducing conditions to convert the at least one cobalt, iron, nickel, ruthenium or rhodium oxide to the metal form.

18. A process for converting a mixture of hydrogen and carbon monoxide gases to hydrocarbons, which process comprises contacting a mixture of hydrogen and carbon monoxide with a Fischer-Tropsch synthesis catalyst according to claim 1.

19. A composition, preferably a fuel composition, comprising hydrocarbons prepared by a process according to claim 18.

20. A process for producing a fuel composition, said process comprising blending hydrocarbons prepared by a process according to claim 18 with one or more fuel components to form the fuel composition.

Description

EXAMPLES

Comparative Example 1

(1) Titania Extrudate not Comprising Zirconium Oxide

(2) Titanium dioxide (Evonik P25) was mixed with distilled water in a mechanical mixer (Vinci MX 0.4) to obtain an extrudable paste with a water to titanium mass ratio of 0.66 g/g. The resultant paste was extruded through a die with an array of 1/16 inch circular orifices using a mechanical extruder (Vinci VTE1) to obtain extrudates with cylindrical shape.

(3) The extrudates were air dried for one hour, then dried at a temperature of between 100 and 120 C. overnight, followed by calcination in air flow at 500 C. for four hours, via a ramp of 2 C./min.

(4) The mechanical strength of the extrudates was analysed using a Varian Benchsaver V200 Tablet Hardness Tester. 50 particles were analysed in each test, and the mean value was calculated.

(5) The surface area of the extrudates was estimated using the BET model to the nitrogen adsorption branch of the isotherms collected at 77K on a Quadrasorb SI unit (Quantachrome).

(6) Pore size and pore volume were characterised using mercury porosimetry conducted on an AutoPore IV (Micromeritics) instrument.

(7) Total pore volume was estimated from mercury intrusion volume at 7000 psia. Pore size distribution of the sample was calculated using the Washburn equation with a contact angle of 130 and a surface tension of bulk mercury of 485 mN/m.

(8) The physical properties of the extrudes were as follows:

(9) Zirconium oxide/titanium oxide ratio: 0 g/g

(10) Crush strength: 4.7 lbf

(11) Geometry: 1/16 inch diameter cylinder

(12) BET surface area: 51 m.sup.2/g

(13) Pore volume: 0.36 ml/g

(14) Mean pore diameter: 33.0 nm.

Example 1

(15) Titania Extrudate Comprising Titanium Oxide (Zirconium Oxide/Titanium Oxide Mass Ratio of 0.1 g/g)

(16) A porous, titania-based extrudate was prepared by mixing titanium oxide (Evonik P25) and an aqueous ammonium zirconium carbonate solution (19.72% zirconium oxide). In the process, the titania powder was first mixed with a predetermined amount of ammonium zirconium carbonate solution in the trough of a mechanical mixer (Vinci MX0.4) and the wetness of the mixture was adjusted with deionised water in order to obtain an extrudable paste. The resultant paste was extruded through a die with 1/16 inch diameter holes using a mechanical extruder (Vinci VTE1) to obtain extrudates with cylindrical rod geometry.

(17) The extrudates were air dried for one hour, then dried at a temperature of between 100 and 120 C. overnight, followed by calcination in air flow at 500 C. for four hours, via a ramp of 2 C./min.

(18) The physical properties of the extrudates were determined as set out in Comparative Example 1, and the results are as follows:

(19) Zirconium oxide/titanium oxide ratio: 0.1 g/g

(20) Geometry: 1/16 inch diameter cylinder

(21) Crush strength: 12.9 lbf

(22) BET surface area: 50 m.sup.2/g

(23) Pore volume: 0.23 ml/g

(24) Mean pore diameter: 25.9 nm.

(25) Compared with the pure titania extrudates prepared in Comparative Example 1, the extrudates of Example 1 having a zirconium oxide, titanium oxide ratio of 0.1 g/g exhibited substantially higher mechanical strength.

Comparative Example 2

(26) Titania Extrudate Comprising Mesopores and Macropores but not Comprising Zirconium Oxide

(27) A porous, titania-based extrudate having macropores and mesopores was prepared by homogenising a mixture of titanium (Evonik P25) and cellulose fibre (Aldrich) with a cellulose/titanium oxide ratio of 0.5 g/g in a plastic jar using a tubular mixer. The resulting mixture was then formulated with deionised water in a mechanical mixer (Simpson Muller) to obtain an extrudable paste.

(28) The resultant paste was extruded through a die with 1/16 inch circular orifice using a mechanical extruder (Bonnet) to obtain extrudates with cylindrical rod geometry.

(29) The extrudates were dried and calcined as set out in Comparative Example 1.

(30) The extrudates of Comparative Example 2 were characterised as set out in Comparative Example 1.

(31) The calcined extrudate of Comparative Example 2 exhibited a bi-modal pore size distribution with peaks at 30.2 nm and 124.9 nm, respectively. The physical properties of the extrudates are set out below:

(32) Zirconium oxide/titanium oxide ratio: 0 g/g

(33) Geometry: 6 inch diameter cylinder

(34) Crush strength: less than 1.0 lbf

(35) BET surface area: 47.3 m.sup.2/g

(36) Pore volume: 0.52 ml/g

(37) Mean pore diameter: bi-modal pores centred at 30.2 nm and 124.9 nm.

Example 2

(38) Titania Extrudate Comprising Mesopores and Macropores Prepared Using a Cellulose Porogen and Comprising Zirconium Oxide (Zirconium Oxide/Titanium Oxide Mass Ratio 0.2 g/g)

(39) A porous, titania-based extrudate comprising mesopores and macropores and further comprising zirconium oxide was prepared by mixing titanium oxide (Evonik P25) and cellulose fibre (Aldrich) with a cellulose/titanium oxide ratio of 0.5 g/g in a plastic jar using a tubular mixer. The resultant mixture was then formulated with a determined amount of ammonium zirconium carbonate solution (19.72 wt % zirconium oxide) in a mechanical mixer (Vinci MX0.4) to obtain a mixture comprising a sufficient amount of ammonium zirconium carbonate so that total conversion of the ammonium zirconium carbonate in the final product would result in a zirconium oxide/titanium oxide ratio of 0.2 g/g. The wetness of the mixture was adjusted with deionised water to obtain an extrudable paste.

(40) The resultant paste was extruded through a die with 1/16 inch diameter holes to obtain extrudates with cylindrical rod geometry using a mechanical extruder (Vinci VTE1).

(41) The extrudates were air dried for one hour, then dried in air flow at a temperature of between 100 and 120 C. overnight. The dried extrudates were calcined in air at 500 C. for four hours, via a ramp of 2 C./min.

(42) The calcined extrudates were characterised as set out in Comparative Example 1, and the results are set out below:

(43) Zirconium oxide/titanium oxide ratio: 0.2 g/g

(44) Geometry: 1/16 inch diameter cylinder

(45) Crush strength: 4.8 lbf

(46) BET surface area: 56 m.sup.2/g

(47) Pore volume: 0.50 ml/g

(48) Mean pore diameter: bi-modal pores centred at 24.1 nm and 168.5 nm, respectively.

(49) A comparison of the results of the Example 2 and Comparative Example 1 shows that incorporating ammonium zirconium carbonate solution before extrusion provides substantially improved mechanical strength in the final extrudate without significantly affecting surface area, pore volume or mean pore diameter/distribution.

Example 3

(50) Porous, Titanic Extrudate Comprising Mesopores and Macropores Further Comprising Zirconium Oxide

(51) The procedure of Example 2 was repeated, with the exception that mixing of titanium oxide and ammonium zirconium carbonate was carried out in an alternative mechanical mixer (Simpson Muller) and extrusion of the paste was carried out using an alternative mechanical extruder (Bonnet Extruder).

(52) The extrudates were dried and calcined as set out in Example 2 and were subsequently characterised as set out in Comparative Example 1. The physical properties of the calcined extrudates are set out below:

(53) Zirconium oxide/titanium oxide ratio: 0.2 g/g

(54) Geometry: 1/16 inch diameter cylinder

(55) Crush strength: 6.2 lbf

(56) BET surface area: 55 m.sup.2/g

(57) Pore volume: 0.46 ml/g

(58) Mean pore diameter: bi-modal pores centred at 24.1 nm and 111.4 nm, respectively.

Example 4

(59) Porous, Titania Extrudate Comprising Mesopores and Macropores Further Comprising Zirconium Oxide

(60) The procedure of Example 3 was repeated, with the exception that the dried extrudates were calcined in air at 600 C. for four hours, via a ramp of 2 C./min.

(61) The extrudates of Example 4 were characterised as set out in Comparative Example and the results are set out below:

(62) Zirconium oxide/titanium oxide ratio: 0.2 g/g

(63) Geometry: 1/16 inch diameter cylinder

(64) Crush strength: 7.3 lbf

(65) BET surface area: 50 m.sup.2/g

(66) Pore volume: 0.5 ml/g

(67) Mean pore diameter: bi-modal pores centred at 24.1 nm and 111.4 nm, respectively.

(68) A comparison of the results of Example 4 and Example 3 indicates that increasing the calcining temperature from 500 C. to 600 C. can significantly increase crush strength.

Example 5

Porous, Titanic Extrudate Comprising Mesopores and Macropores Further Comprising Zirconium Oxide

(69) The procedure of Example 3 was repeated, with the exception that the homogenous paste was extruded through an array of 1/16 inch cylindrical trilobe orifices to obtain extrudates with cylindrical trilobe geometry. The extrudates were dried and calcined as set out in Example 2, and were characterised as set out in Comparative Example 1. The physical properties of the extrudates are set out below:

(70) Zirconium oxide/titanium oxide ratio: 0.2 g/g

(71) Geometry: 1/16 inch diameter cylindrical trilobe

(72) Crush strength: 10.0 lbf

(73) BET surface area: 55 m.sup.2/g

(74) Pore volume: 0.48 ml/g

(75) Mean pore diameter: bi-modal pores centred at 24.1 nm and 111.4 nm, respectively.

(76) A comparison of the results of Example 5 and Example 3 indicates that changing the geometry of the extrudates from cylindrical to cylindrical trilobes can significantly increase crush strength.

Comparative Example 3

(77) Porous Titania Extrudate Comprising Mesopores and Macropores but not Comprising Zirconium Oxide

(78) The procedure of Example 5 was repeated, with the exception that the ammonium zirconium carbonate solution was replaced by deionised water. The resultant paste was extruded, dried and calcined as set out in Example 5.

(79) The calcined extrudates were characterised as set out in Comparative Example 1, and the results are set out below:

(80) Zirconium oxide/titanium oxide ratio: 0 g/g

(81) Geometry: 1/16 inch diameter cylindrical trilobe

(82) Crush strength: less than 1.0 lbf

(83) BET surface area: 51.8 m.sup.2/g

(84) volume: 0.52 ml/g

(85) Mean pore diameter: bi-modal pores centred at 27.9 nm and 139.4 nm, respectively.

(86) A comparison of the results of Comparative Example 3 and Example 5 indicate that, in the absence of ammonium zirconium carbonate/zirconium oxide, trilobe geometry does not significantly contribute to crush strength.

(87) In summary, comparing the titania extrudates with bi-modal pores (Comparative Example 2 versus Examples 3-4; Comparative Example 3 versus Example 5), the extrudates prepared using ammonium zirconium carbonate generally exhibit equivalent pore volumes and surface areas, but substantially improved mechanical strength, irrespective of the formulation equipment and geometry of the extrudates.

(88) The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Instead, unless otherwise specified, each such dimension is intended to mean both the recited value and a functionally equivalent range surrounding that value. For example, a dimension disclosed as 40 mm is intended to mean about 40 mm.

(89) Every document cited herein, including any cross referenced or related patent or application, is hereby incorporated herein by reference in its entirety unless expressly excluded or otherwise limited. The citation of any document is not an admission that it is prior art with respect to any invention disclosed or claimed herein or that it alone, or in any combination with any other reference or references, teaches, suggests or discloses any such invention. Further, to the extent that any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to that term in this document shall govern.

(90) While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope and spirit of this invention.