Modified catalyst supports and catalysts supported thereon
A modified catalyst support is described in the form of titania particles with a volume-median diameter in the range 100 to 1000 μm modified with one or more refractory oxides of metals selected from the group consisting of zirconium, lanthanum, cerium, yttrium and neodymium, wherein the total refractory oxide content of the modified catalyst support is in the range of 0.1 to 15% by weight, and the modified catalyst support has a pore volume in the range of 0.2 to 0.6 cm 3 /g and an average pore diameter in the range of 30 to 60 nm. The modified catalyst support may be used to prepare cobalt Fischer-Tropsch catalysts suitable for use in fixed bed processes.
1. A modified catalyst support in the form of titania particles with a volume-median diameter in the range of 100 to 1000 mm modified with one or more refractory oxides of metals selected from the group consisting of zirconium, lanthanum, cerium, yttrium and neodymium, wherein the total refractory oxide content of the modified catalyst support is in the range of 0.1 to 15% by weight, and the modified catalyst support has a pore volume in the range of 0.2 to 0.6 cm 3 /g and an average pore diameter in the range of 30 to 60 nm.
2. The modified catalyst support according to claim 1 , wherein the volume-median diameter, D[v,0.5], is in the range of 300 to 900 mm.
3. The modified catalyst support according to claim 1 , wherein the titania particles are spherical with a sphericity (w), of at least about 0.90.
4. The modified catalyst support according to claim 1 , wherein the modified catalyst support has an anatase content of at least 70% by weight of the support.
5. The modified catalyst support according to claim 1 , wherein the modified catalyst support has a chloride content of less than 1500 ppmw.
6. The modified catalyst support according to claim 1 , wherein the refractory oxide consists of zirconia, ZrO 2 .
7. The modified catalyst support according to claim 1 , wherein the refractory oxide content of the modified catalyst support is in the range of 1.5 to 8.5% by weight.
8. The modified catalyst support according to claim 1 , wherein the pore volume is in the range of 0.30 to 0.50 cm 3 /g.
9. The modified catalyst support according to claim 1 , wherein the average pore diameter is in the range of 40 to 60 nm.
10. The modified catalyst support according to claim 1 , wherein the modified catalyst support has a BET surface area in the range of 25 to 75 m 2 /g.
11. A catalyst precursor comprising cobalt oxide crystallites disposed within pores of the modified catalyst support according to claim 1 .
12. The catalyst precursor according to claim 11 , wherein the cobalt oxide crystallites have an average particle size in the range of 6 to 18 nanometres (nm).
13. The catalyst precursor according to claim 11 , wherein a ratio of average cobalt oxide crystallite size to the average pore diameter is in the range of 0.1:1 to 0.6:1.
14. The catalyst precursor according to claim 11 , wherein the catalyst precursor has a cobalt content in the range of 5 to 25% by weight, expressed as Co on a loss free basis.
15. The catalyst precursor according to claim 11 , wherein the catalyst precursor comprises between 1 and 15% by weight in total of one or more additives, selected from oxides of one or more additive metals selected from nickel (Ni), zinc (Zn), thorium (Th), magnesium (Mg), manganese (Mn) or silicon (Si).
16. The catalyst precursor according to claim 11 , wherein the catalyst precursor comprises between 0.01 and 1.00% by weight in total of one or more promoter metals selected from rhodium (Rh), iridium (Ir), ruthenium (Ru), rhenium (Re), platinum (Pt) and palladium (Pd).
17. A process to produce hydrocarbons from a synthesis gas comprising hydrogen and carbon monoxide using the catalyst precursor according to claim 16 in a reactor.
18. A method for preparing the catalyst precursor according to claim 11 comprising the steps of impregnating the modified catalyst support with a cobalt compound to form an impregnated modified titania support and drying and calcining the impregnated modified titania support to form cobalt oxide crystallites within the pores of the modified catalyst support.
19. A combination of the catalyst precursor according to claim 11 , disposed within a catalyst carrier suitable for use in a reaction tube of a reactor.
20. A process to produce hydrocarbons from a synthesis gas comprising hydrogen and carbon monoxide using the combination according to claim 19 in a reactor.
21. The combination of the catalyst precursor according to claim 11 , disposed within channels in a microchannel reactor.
22. A process to produce hydrocarbons from a synthesis gas comprising hydrogen and carbon monoxide using the catalyst precursor according to claim 11 in a reactor.
23. A catalyst comprising cobalt metal crystallites disposed within the pores of the modified catalyst support according to claim 1 .
24. A method for preparing the modified catalyst support according to claim 1 , comprising the steps of impregnating titania particles with a volume-median diameter in the range of 100 to 1000 mm, a pore volume in the range of 0.2 to 0.6 cm 3 /g and an average pore diameter in the range of 30 to 60 nm, with a solution of one or more metals selected from the group consisting of zirconium, lanthanum, cerium, yttrium and neodymium to form an impregnated titania support, and drying and calcining the impregnated titania support to form a refractory metal oxide modified catalyst support comprising refractory oxide in the range of 0.1 to 15% by weight.
25. The method according to claim 24 , wherein the calcining step is performed in a moving bed reactor at a temperature in the range of 400 to 900° C.