Process for preparing a cobalt-containing hydrocarbon synthesis catalyst precursor

Abstract

A process for preparing a cobalt-containing hydrocarbon synthesis catalyst precursor includes calcining a loaded catalyst support comprising a catalyst support supporting a cobalt compound. The calcination includes heating the loaded catalyst support over a heating temperature range of 90 C. to 220 C. using (i) one or more high heating rate periods during the heating over the heating temperature range wherein heating of the loaded catalyst support takes place at a heating rate of at least 10 C./minute, and wherein a gas velocity of at least 5 m.sup.3.sub.n/kg cobalt compound/hour is effected over the loaded catalyst support, and (ii) one or more low heating rate periods during the heating over the heating temperature range wherein heating of the loaded catalyst support takes place at a heating rate of less than 6 C./minute. The cobalt compound is thereby calcined, with a cobalt-containing hydrocarbon synthesis catalyst precursor being produced.

Claims

1. A process for preparing a cobalt-containing hydrocarbon synthesis catalyst precursor, which process includes calcining a loaded catalyst support comprising a catalyst support supporting a cobalt salt to decompose the cobalt salt and/or to cause the cobalt salt to react with oxygen, the calcination thereby converting the cobalt salt into a cobalt oxide, the calcination including heating the loaded catalyst support over a heating temperature range of 90 C. to 220 C. using one or more high heating rate periods during the heating over the heating temperature range wherein heating of the loaded catalyst support takes place at a heating rate of at least 10 C./minute, and wherein a gas flow with a space velocity of at least 5 m.sup.3.sub.n/kg cobalt salt/hour is effected over the loaded catalyst support; and one or more low heating rate periods during the heating over the heating temperature range wherein heating of the loaded catalyst support takes place at a heating rate of less than 6 C./minute, thereby to calcine the cobalt salt, with a cobalt-containing hydrocarbon synthesis catalyst precursor being prepared.

2. The process according to claim 1, wherein the heating over the one or more high heating rate periods increases the temperature of the loaded catalyst support by at least 10 C.

3. The process according to claim 1, wherein the one or more high heating rate periods covers only part of the heating temperature range from 90 C. to 220 C.

4. The process according to claim 3, wherein the one or more high heating rate periods is carried out over at least 50% of the heating temperature range of 90 C. to 220 C.

5. The process according to claim 1, which employs two or more high heating rate periods, with at least one of the high heating rate periods being directly followed by a low heating rate period.

6. The process according to claim 1, wherein the one or more low heating rate periods covers the heating temperature range not covered by the high heating rate period(s).

7. The process according to claim 1, wherein the calcination is also carried out above 220 C., with the one or more high heating rate periods being carried out over at least 50% of the whole heating temperature range above 90 C.

8. The process according to claim 1, wherein the heating rate during the high heating rate period(s) is at least 15 C./min.

9. The process according to claim 1, wherein the space velocity of the gas flow during the high heating rate period(s) is at least 10 m.sup.3.sub.n/kg cobalt salt/hour.

10. The process according to claim 1, wherein gas flow over the loaded catalyst support is also affected during the one or more low heating rate periods.

11. The process according to claim 10, wherein the space velocity of the gas flow during the low heating rate period(s) is at least 5 m.sup.3.sub.n/kg cobalt salt/hour.

12. The process according to claim 11, wherein the space velocity of the gas flow during the low heating rate period(s) is the same as the space velocity of the gas flow during the high heating rate period(s).

13. The process according to claim 1, wherein the heating rate during the low heating rate period(s) is less than 5 C./minute.

14. The process according to claim 1, wherein at least one low heating rate period is provided in the heating temperature range above 120 C. and below 190 C.

15. The process according to claim 1, which employs at least one high heating rate period extending over at least part of a first heating temperature range; at least one high heating rate period extending over at least part of a second heating temperature range above the temperature range of the first heating temperature range; and at least one low heating rate period which is between the high heating rate period in the first temperature range and the high heating rate period in the second temperature range.

16. The process according to claim 1, which employs at least one high heating rate period extending over at least part of a first heating temperature range; at least one high heating rate period extending over at least part of a second heating temperature range above the temperature range of the first temperature range; at least one high heating rate period extending over at least part of a third heating temperature range above the temperature range of the second temperature range; at least one low heating rate period which is between the high heating rate period in the first temperature range and the high heating rate period in the second temperature range; and at least one low heating rate period which is between the high heating rate period in the second temperature range and the high heating rate period in the third temperature range.

17. A process for preparing a hydrocarbon synthesis catalyst which includes preparing a catalyst precursor according to claim 1 and then reducing the said catalyst precursor, to obtain the catalyst.

18. The process according to claim 17, wherein the hydrocarbon synthesis catalyst is a Fischer-Tropsch synthesis catalyst.

19. A hydrocarbon synthesis process comprising preparing a hydrocarbon synthesis catalyst as claimed in claim 17 and contacting hydrogen with carbon monoxide at a temperature above 100 C. and a pressure of at least 10 bar with the catalyst in order to produce hydrocarbons and, optionally, oxygenates of hydrocarbons.

20. The process according to claim 19, which includes a hydroprocessing step for converting the hydrocarbons and, optionally, oxygenates thereof to liquid fuels and/or chemicals.

Description

EXAMPLE 1 (INVENTIVE) (TORBED REACTOR (FLUIDISED BED REACTOR) EXAMPLE C1313/1 T)

(1) A particulate supported cobalt-based or cobalt-containing Fischer-Tropsch synthesis catalyst precursor, which, on activation, produces a 16 g Co/100 g Al.sub.2O.sub.3 proprietary slurry phase Fischer-Tropsch synthesis catalyst of the Applicant, was investigated.

(2) The calcination in this example was executed by means of 3 high heating rate periods and 2 low heating rate periods in the 90 to 220 C. range, all in a TORBED reactor (fluidised bed reactor).

(3) Cobalt Impregnation

(4) A representative batch of this pre-reduced catalyst precursor was specifically prepared as follows: Puralox SCCa, pore volume of 0.48 ml/g, from SASOL Germany GmbH of Uberseering 40, 22297 Hamburg, Germany was modified with silicon (using TEOS in ethanol) such that the final silicon level was between 1.3 mass % Si/g of support. A cobalt nitrate containing precursor (or loaded catalyst support) was prepared by incipient wetness impregnation. 15 kg of the above mentioned silica modified gamma alumina support was impregnated with a solution of 12.1 kg of Co(NO.sub.3).sub.2.6H.sub.2O and 7.2 g of Pt(NH.sub.3).sub.4(NO.sub.3).sub.2, and stirred at 69 C. for 2 hours.

(5) Calcination of Cobalt Nitrate Containing Precursor

(6) The precursor was calcined in a TORBED reactor (fluidised bed reactor) (Torftech Ltd, Thatcham, RG19,6HW, United Kingdom) by loading the cobalt nitrate containing precursor batch into the feeder hopper. The temperature of the TORBED reactor (fluidised bed reactor) was set at 100 C., the air flow was set at 75 m3.Math.h.sup.1 and the vibrator feeder speed was set at 10 kg.Math.h.sup.1. After the temperature had stabilized, the valve to the vibrator feeder was opened and the cobalt nitrate containing precursor (at room temperature) was fed by vibration into the TORBED reactor (fluidised bed reactor). The heating rate for the precursor was 22 C./min (i.e. high heating rate period) up to 92 C., while the space velocity was 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour. Thereafter the precursor was treated for about 8 minutes in the TORBED reactor (fluidised bed reactor), while the temperature increased from 92 to 100 C., with a heating rate of 1 C./min (i.e. low heating rate period) and a space velocity of 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour.

(7) The resultant partially calcined cobalt nitrate containing precursor was unloaded from the reactor hopper and cyclone hopper, and placed into the feeder hopper. The temperature of the TORBED reactor (fluidised bed reactor) was set at 150 C., the air flow was set at 75 m3.Math.h.sup.1 and the vibrator feeder speed was set at 10 kg.Math.h.sup.1. After the temperature had stabilized, the valve to the vibrator feeder was opened and the partially calcined cobalt nitrate containing precursor (at room temperature) was fed by vibration into the TORBED reactor (fluidised bed reactor). The heating rate for the precursor was 39 C./min (i.e. high heating rate period) up to 141 C., while the space velocity was 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour. Thereafter the precursor was treated for about 11 minutes in the TORBED reactor (fluidised bed reactor), while the temperature increased from 141 to 150 C., with a heating rate of 0.8 C./min (i.e. low heating rate period) and an air space velocity of 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour

(8) The resultant cobalt oxide precursor was unloaded from the reactor hopper and cyclone hopper, and placed into the feeder hopper. The temperature of the TORBED reactor (fluidised bed reactor) was set at 270 C., the air flow was set at 75 m3.Math.h.sup.1 and the vibrator feeder speed was set at 10 kg.Math.h.sup.1. After the temperature had stabilized, the valve to the vibrator feeder was opened and the cobalt oxide precursor (at room temperature) was fed by vibration into the TORBED reactor (fluidised bed reactor). The heating rate for the precursor was 77 C./min (i.e. high heating rate period) up to 255 C., while the space velocity was 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour. Thereafter the precursor was treated for about 14 minutes in the TORBED reactor (fluidised bed reactor), while the temperature increased from 255 to 270 C., with a heating rate of 1.1 C./m in and a space velocity of 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour. The resultant particulate supported cobalt-based Fischer-Tropsch catalyst precursor was unloaded from the reactor hopper and cyclone hopper.

EXAMPLE 2 (INVENTIVE) (TORBED REACTOR (FLUIDISED BED REACTOR) EXAMPLE C1316/1 T)

(9) The calcination in this example was executed by means of 4 high heating rate periods and 3 low heating rate periods in the 90 to 220 C. range, all in a TORBED reactor (fluidised bed reactor).

(10) The particulate supported cobalt containing Fischer-Tropsch synthesis catalyst precursor of this example was prepared in a similar manner to that of Example 1, however the calcination of the dried cobalt nitrate containing precursor (or loaded catalyst support) was done as follows:

(11) Calcination of the Cobalt Nitrate Containing Precursor

(12) The precursor was calcined in a TORBED reactor (fluidised bed reactor) by loading the cobalt nitrate containing precursor batch into the feeder hopper. The temperature of the TORBED reactor (fluidised bed reactor) was set at 100 C., the air flow was set at 75 m3.Math.h.sup.1 and the vibrator feeder speed was set at 10 kg.Math.h.sup.1. After the temperature had stabilized, the valve to the vibrator feeder was opened and the cobalt nitrate precursor (at room temperature) was fed by vibration into the TORBED reactor (fluidised bed reactor). The heating rate for the precursor was 22 C./min (i.e. high heating rate period) up to 92 C., while the space velocity was 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour. Thereafter the precursor was treated for about 8 minutes in the TORBED reactor (fluidised bed reactor), while the temperature increased from 92 C. to 100 C., with a heating rate of 1 C./m in (i.e. low heating rate period) and a space velocity of 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour.

(13) The resultant partially calcined cobalt nitrate containing precursor was unloaded from the reactor hopper and cyclone hopper, and placed into the feeder hopper. The temperature of the TORBED reactor (fluidised bed reactor) was set at 150 C., the air flow was set at 75 m3.Math.h.sup.1 and the vibrator feeder speed was set at 10 kg.Math.h.sup.1. After the temperature had stabilized, the valve to the vibrator feeder was opened and the partially calcined cobalt nitrate containing precursor (at room temperature) was fed by vibration into the TORBED reactor (fluidised bed reactor). The heating rate for the precursor was 39 C./min (i.e. high heating rate period) up to 141 C., while the space velocity was 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour. Thereafter the precursor was treated for about 11 minutes in the TORBED reactor (fluidised bed reactor), while the temperature increased from 141 C. to 150 C., with a heating rate of 0.8 C./min (i.e. low heating rate period) and a space velocity of 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour.

(14) The resultant partially calcined cobalt nitrate containing precursor was unloaded from the reactor hopper and cyclone hopper, and placed into the feeder hopper. The temperature of the TORBED reactor (fluidised bed reactor) was set at 170 C., the air flow was set at 75 m3.Math.h.sup.1 and the vibrator feeder speed was set at 10 kg.Math.h.sup.1. After the temperature had stabilized, the valve to the vibrator feeder was opened and the partially calcined cobalt nitrate containing precursor (at room temperature) was fed by vibration into the TORBED reactor (fluidised bed reactor). The heating rate for the precursor was 47 C./min (i.e. high heating rate period) up to 165 C., while the space velocity was 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour. Thereafter the precursor was treated for about 5 minutes in the TORBED reactor (fluidised bed reactor), while the temperature increased from 165 C. to 170 C., with a heating rate of 1 C./min (i.e. low heating rate period) and a space velocity of 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour. The resultant cobalt oxide precursor was unloaded from the reactor hopper and cyclone hopper, and placed into the feeder hopper. The temperature of the TORBED reactor (fluidised bed reactor) was set at 270 C., the air flow was set at 75 m3.Math.h.sup.1 and the vibrator feeder speed was set at 10 kg.Math.h.sup.1. After the temperature had stabilized, the valve to the vibrator feeder was opened and the cobalt nitrate precursor (at room temperature) was fed by vibration into the TORBED reactor (fluidised bed reactor). The heating rate for the precursor was 56 C./min (i.e. high heating rate period) up to 248 C., while the space velocity was 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour. Thereafter the precursor was treated for about 10 minutes in the TORBED reactor (fluidised bed reactor), while the temperature increased from 248 C. to 270 C., with a heating rate of 2.1 C./min and a space velocity of 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour. The resultant particulate supported cobalt-based Fischer-Tropsch synthesis catalyst precursor was unloaded from the reactor hopper and cyclone hopper.

EXAMPLE 3 (INVENTIVE) (ROTARY CALCINER/TORBED REACTOR (FLUIDISED BED REACTOR) EXAMPLE C1320/1 T)

(15) The calcination in this example was executed by means of 1 low heating rate period in a rotary kiln calciner followed by 1 high heating rate period in a TORBED reactor (fluidised bed reactor), all in the 90 C. to 220 C. range.

(16) The particulate supported cobalt containing Fischer-Tropsch synthesis catalyst precursor of this example was prepared in a similar manner to that of Example 1, however the calcination of the dried cobalt nitrate containing precursor (or loaded catalyst support) was done as follows:

(17) Calcination of Cobalt Nitrate Containing Precursor

(18) The precursor was calcined in a rotary calciner by loading the cobalt nitrate containing precursor batch (at room temperature) into the stainless steel calcination tube. The temperature of the rotary calciner was increased by 1 C./min from room temperature to 130 C. and the air flow was low, being obtained by natural convection inside the calcination tube (i.e. low heating rate period).

(19) The resultant partially calcined cobalt nitrate containing precursor was left to cool to room temperature where after the material was further calcined in a TORBED reactor (fluidised bed reactor). The partially calcined cobalt nitrate containing precursor batch was calcined in the TORBED reactor (fluidised bed reactor) by loading the cobalt nitrate containing precursor into the feeder hopper. The temperature of the TORBED reactor (fluidised bed reactor) was set at 270 C., the air flow was set at 75 m3.Math.h.sup.1 and the vibrator feeder speed was set at 10 kg.Math.h.sup.1. After the temperature had stabilized, the valve to the vibrator feeder was opened and the cobalt nitrate containing precursor (at room temperature) was fed by vibration into the TORBED reactor (fluidised bed reactor). The heating rate for the precursor was 77 C./min up to 255 C., while the space velocity was 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour (i.e. high heating rate period). Thereafter the precursor was treated for about 14 minutes in the TORBED reactor (fluidised bed reactor), while the temperature increased from 255 C. to 270 C., with a heating rate of 1.1 C./m in and a space velocity of 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour. The resultant particulate supported cobalt-based Fischer-Tropsch synthesis catalyst precursor was unloaded from the reactor hopper and cyclone hopper.

EXAMPLE 4 (INVENTIVE) (FLUIDISED BED CALCINER/TORBED REACTOR (FLUIDISED BED REACTOR) EXAMPLE C1317/1 T)

(20) The calcination in this example was executed by means of 1 low heating rate period in a fluidised bed calciner followed by 1 high heating rate period in a TORBED reactor (fluidised bed reactor), all in the 90 C. to 220 C. range.

(21) The particulate supported cobalt-containing Fischer-Tropsch synthesis catalyst precursor of this example was prepared in a similar manner to that of Example 1, however the calcination of the dried cobalt nitrate containing precursor (or loaded catalyst support) was done as follows:

(22) Calcination of Cobalt Nitrate Containing Precursor

(23) The precursor was calcined in a fluidised bed calciner by loading the cobalt nitrate containing precursor batch (at room temperature) into the fluidised bed calcination unit. The temperature of the fluidised bed calciner was increased by 1 C./m in from room temperature to 130 C. and the air flow was 2 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour (i.e. low heating rate period).

(24) The resultant partially calcined cobalt nitrate containing precursor was left to cool to room temperature where after the material was further calcined in a TORBED reactor (fluidised bed reactor). The partially calcined cobalt nitrate containing precursor was calcined in the TORBED reactor (fluidised bed reactor) by loading the cobalt nitrate containing precursor batch into the feeder hopper. The temperature of the TORBED reactor (fluidised bed reactor) was set at 270 C., the air flow was set at 75 m3.Math.h.sup.1 and the vibrator feeder speed was set at 10 kg.Math.h.sup.1. After the temperature had stabilized, the valve to the vibrator feeder was opened and the cobalt nitrate precursor (at room temperature) was fed by vibration into the TORBED reactor (fluidised bed reactor). The heating rate for the precursor was 77 C./min up to 255 C., while the space velocity was 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour (i.e. high heating rate period). Thereafter the precursor was treated for about 14 minutes in the TORBED reactor (fluidised bed reactor), while the temperature increased from 255 C. to 270 C., with a heating rate of 1.1 C./min and a space velocity of 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour. The resultant particulate supported cobalt-based Fischer-Tropsch synthesis catalyst precursor was unloaded from the reactor hopper and cyclone hopper.

EXAMPLE 5 (COMPARATIVE) (FLUIDISED BED CALCINED EXAMPLE C1212/1 T)

(25) The calcination in this example was executed by means of 1 low heating rate period in a fluidised bed calciner in the 90 to 220 C. range.

(26) The precursor of this example was prepared in a similar manner to that of Example 1.

(27) Calcination of cobalt nitrate containing precursor (or loaded catalyst support) The precursor was calcined in a fluidised bed calciner by loading the cobalt nitrate containing precursor batch into the fluidised bed calcination unit. The temperature of the fluidised bed calciner was increased by 1 C./m in from room temperature to 250 C. and the air flow was 2 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour (i.e. low heating rate period). The calcined cobalt oxide containing precursor was left in the calciner to cool to room temperature after which it was unloaded.

EXAMPLE 6 (INVENTIVE) (TORBED REACTOR (FLUIDISED BED REACTOR) EXAMPLE C1338/1 S)

(28) The calcination in this example was executed by means of 3 high heating rate periods and 2 low heating rate periods in the 90 to 220 C. range all in a TORBED reactor (fluidised bed reactor).

(29) The precursor of this example was prepared and calcined in a similar manner to that of Example 1. The Puralox support was modified with aqueous monosilicic acid and contained a higher Si load (1.9%) compared to Example 1 (1.3%).

EXAMPLE 7 (INVENTIVE) (TORBED REACTOR (FLUIDISED BED REACTOR) EXAMPLE C1339/1 S)

(30) The calcination in this example was executed by means of 4 high heating rate periods and 3 low heating rate periods in the 90 to 220 C. range al in a TORBED reactor (fluidised bed reactor).

(31) The precursor of this example was prepared and calcined in a similar manner to that of Example 2.

(32) The Puralox support was modified with aqueous monosilicic acid and contained a higher Si load (1.9%) compared to Example 1 (1.3%).

EXAMPLE 8 (INVENTIVE) (TORBED REACTOR (FLUIDISED BED REACTOR)/FLUIDISED BED CALCINER EXAMPLE C1342/1 S)

(33) The calcination in this example was executed by means of 2 high and 2 low heating rate periods in a TORBED reactor (fluidized bed reactor), followed by 1 low heating period in a fluidised bed calciner, all in the 90 C. to 220 C. range.

(34) The cobalt nitrate containing precursor (or loaded catalyst support) of this example was prepared in a similar manner to that of Example 1.

(35) The Puralox support was modified with aqueous monosilicic acid and contained a higher Si load (1.9%) compared to Example 1 (1.3%).

(36) The calcination of the cobalt nitrate containing precursor was done as follows:

(37) Calcination of Cobalt Nitrate Containing Precursor

(38) The precursor was calcined in a TORBED reactor (fluidised bed reactor) by loading the cobalt nitrate containing precursor batch into the feeder hopper. The temperature of the TORBED reactor (fluidised bed reactor) was set at 100 C., the air flow was set at 75 m3.Math.h.sup.1 and the vibrator feeder speed was set at 10 kg.Math.h.sup.1. After the temperature had stabilized, the valve to the vibrator feeder was opened and the cobalt nitrate precursor (at room temperature) was fed by vibration into the TORBED reactor (fluidised bed reactor). The heating rate for the precursor was 22 C./min (i.e. high heating rate period) up to 92 C., while the space velocity was 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour. Thereafter the precursor was treated for about 8 minutes in the TORBED reactor (fluidised bed reactor), while the temperature increased from 92 C. to 100 C., with a heating rate of 1 C./m in (i.e. low heating rate period) and a space velocity of 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour. The resultant partially calcined cobalt nitrate containing precursor was unloaded from the reactor hopper and cyclone hopper, and placed into the feeder hopper.

(39) The temperature of the TORBED reactor (fluidised bed reactor) was set at 150 C., the air flow was set at 75 m3.Math.h.sup.1 and the vibrator feeder speed was set at 10 kg.Math.h.sup.1. After the temperature had stabilized, the valve to the vibrator feeder was opened and the partially calcined cobalt nitrate containing precursor (at room temperature) was fed by vibration into the TORBED reactor (fluidised bed reactor). The heating rate for the precursor was 39 C./min (i.e. high heating rate period) up to 141 C., while the space velocity was 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour. Thereafter the precursor was treated for about 11 minutes in the TORBED reactor (fluidised bed reactor), while the temperature increased from 141 C. to 150 C., with a heating rate of 0.8 C./min (i.e. low heating rate period) and a space velocity of 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour. The resultant partially calcined cobalt nitrate containing precursor was unloaded from the reactor hopper and cyclone hopper, and placed into the fluidised bed calciner.

(40) The partially calcined cobalt nitrate containing precursor was calcined in the fluidised bed calciner by loading the cobalt nitrate containing precursor batch into the fluidised bed calcinations unit. The temperature of the fluidised bed calciner was increased by 1 C./m in from room temperature to 250 C. and the air flow was 2 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour (i.e. low heating rate period). The resultant calcined cobalt oxide containing precursor, i.e. particulate supported cobalt-containing Fischer-Tropsch synthesis catalyst precursor, was left to cool to room temperature where after the material was unloaded.

EXAMPLE 9 (INVENTIVE) (TORBED REACTOR (FLUIDISED BED REACTOR)/FLUIDISED BED CALCINER/TORBED REACTOR (FLUIDISED BED REACTOR) CALCINER EXAMPLE C1343/1 S)

(41) The calcination in this example was executed by means of 2 high and 2 low heating rate periods in a TORBED reactor (fluidised bed reactor), followed by 1 low heating rate period in a fluidised bed calciner, and finally another high heating rate period in a TORBED reactor (fluidised bed reactor), all in the 90 to 220 C. range.

(42) The cobalt nitrate containing precursor or loaded catalyst support of this example was prepared in a similar manner to that of Example 1.

(43) The Puralox support was modified with aqueous monosilicic acid and contained a higher Si load (1.9%) compared to Example 1 (1.3%).

(44) The calcination of the cobalt nitrate containing precursor was done as follows:

(45) Calcination of Cobalt Nitrate Containing Precursor

(46) The precursor was calcined in a TORBED reactor (fluidised bed reactor) by loading the cobalt nitrate containing precursor batch into the feeder hopper. The temperature of the TORBED reactor (fluidised bed reactor) was set at 100 C., the air flow was set at 75 m3.Math.h.sup.1 and the vibrator feeder speed was set at 10 kg.Math.h.sup.1. After the temperature had stabilized, the valve to the vibrator feeder was opened and the cobalt nitrate precursor (at room temperature) was fed by vibration into the TORBED reactor (fluidised bed reactor). The heating rate for the precursor was 22 C./min (i.e. high heating rate period) up to 92 C., while the space velocity was 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour. Thereafter the precursor was treated for about 8 minutes in the TORBED reactor (fluidised bed reactor), while the temperature increased from 92 C. to 100 C., with a heating rate of 1 C./m in (i.e. low heating rate period) and a space velocity of 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour.

(47) The resultant partially calcined cobalt nitrate containing precursor was unloaded from the reactor hopper and cyclone hopper, and placed into the feeder hopper. The temperature of the TORBED reactor (fluidised bed reactor) was set at 150 C., the air flow was set at 75 m3.Math.h.sup.1 and the vibrator feeder speed was set at 10 kg.Math.h.sup.1. After the temperature had stabilized, the valve to the vibrator feeder was opened and the partially calcined cobalt nitrate containing precursor (at room temperature) was fed by vibration into the TORBED reactor (fluidised bed reactor). The heating rate for the precursor was 39 C./min (i.e. high heating rate period) up to 141 C., while the space velocity was 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour. Thereafter the precursor was treated for about 11 minutes in the TORBED reactor (fluidised bed reactor), while the temperature increased from 141 C. to 150 C., with a heating rate of 0.8 C./min (i.e. low heating rate period) and a space velocity of 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour.

(48) The resultant partially calcined cobalt nitrate containing precursor (at room temperature) was unloaded from the reactor hopper and cyclone hopper, and placed into the fluidised bed calciner. The temperature of the fluidised bed calciner was increased by 1 C./min from room temperature to 160 C. and the air flow was 2 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour (i.e. low heating rate period).

(49) The resultant partially calcined cobalt nitrate containing precursor was thereafter calcined in a TORBED reactor (fluidised bed reactor) by loading the cobalt nitrate containing precursor batch into the feeder hopper. The temperature of the TORBED reactor (fluidised bed reactor) was set at 270 C., the air flow was set at 75 m3.Math.h.sup.1 and the vibrator feeder speed was set at 10 kg.Math.h.sup.1. After the temperature had stabilized, the valve to the vibrator feeder was opened and the cobalt nitrate precursor (at room temperature) was fed by vibration into the TORBED reactor (fluidised bed reactor). The heating rate for the precursor was 77 C./min up to 255 C., while the space velocity was 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour (i.e. high heating rate period). Thereafter the precursor was treated for about 14 minutes in the TORBED reactor (fluidised bed reactor), while the temperature increased from 255 C. to 270 C., with a heating rate of 1.1 C./min and a space velocity of 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour. The resultant cobalt oxide precursor was unloaded from the reactor and cyclone hopper.

EXAMPLE 10A AND 10B (COMPARATIVE) (FLUIDISED BED CALCINER EXAMPLES C1107/1 T AND C1107/2 T)

(50) The calcination in this example was executed by means of 1 low heating period in a fluidised bed calciner in the 90 to 220 C. range.

(51) Particulate supported cobalt-based Fischer-Tropsch synthesis catalyst precursors, which, on activation, produce a 30 g Co/100 g Al.sub.2O.sub.3 and a 16 g Co/100 g Al.sub.2O.sub.3 proprietary slurry phase Fischer-Tropsch synthesis catalyst of the Applicant, were investigated.

(52) Cobalt Impregnation

(53) First impregnation to obtain a precursor with 16 g Co/100gSupport (Example 10A)

(54) A representative batch of this pre-reduced catalyst precursor was specifically prepared as follows: Puralox SCCa, pore volume of 0.48 ml/g, from SASOL Germany GmbH of Uberseering 40, 22297 Hamburg, Germany was modified with silicon such that the final silicon level was 1.3 mass % Si/g of support. A cobalt nitrate containing precursor was prepared by slurry impregnation. 50.0 g of the above mentioned silica modified gamma alumina support was impregnated with a solution of 50.0 g H.sub.2O, 39.5 g of Co(NO.sub.3).sub.2.6H.sub.2O and 0.0248 g of Pt(NH.sub.3).sub.4(NO.sub.3).sub.2, and dried under increased temperature from 60 to 85 C. and vacuum from 260 to 50 mbar for 6 hours. This precursor was calcined as described below.

(55) Second impregnation to obtain a precursor with 30 g Co/100gSupport (Example 10B)

(56) 50.0 g of the calcined first impregnated precursor was used to prepare a precursor containing 30 g Co/100 g Support. The calcined precursor was impregnated with a solution of 50.0 g H.sub.2O, 28.38 g of Co(NO.sub.3).sub.2.6H.sub.2O and 0.0407 g of Pt(NH.sub.3).sub.4(NO.sub.3).sub.2, and dried under increased temperature from 60 to 85 C. and vacuum from 260 to 50 mbar for 6 hours. This precursor was calcined as described below.

(57) Calcination of Dried Cobalt Nitrate Containing Precursor

(58) The dried precursor (at room temperature) was loaded into a fluidised bed calcination unit. Calcination was performed at atmospheric pressure. The air flow was set at 2 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour. The temperature was increased by 1 C./min (i.e. low heating rate period) from room temperature to 250 C. and held for 6 hours at 250 C. The calcined precursor was left to cool down to room temperature and unloaded.

EXAMPLE 11A AND 11B (COMPARATIVE) (TORBED REACTOR (FLUIDISED BED REACTOR) CALCINER EXAMPLES C742/1 T AND C742/2 T)

(59) The calcination in this example was executed by means of 1 high heating rate period in a TORBED calciner (TORBED reactorfluidised bed reactor) in the 90 to 220 C. range.

(60) Particulate supported cobalt-based Fischer-Tropsch synthesis catalyst precursors, which, on activation, produce a 30 g Co/100 g Al.sub.2O.sub.3 and a 16 g Co/100 g Al.sub.2O.sub.3 proprietary slurry phase Fischer-Tropsch synthesis catalyst of the Applicant, were investigated.

(61) Cobalt Impregnation

(62) Example 11A C742/1: First impregnation to obtain a precursor with 16 gCo/100gSupport.

(63) A representative batch of this pre-reduced catalyst precursor was specifically prepared as follows: Puralox SCCa, pore volume of 0.48 ml/g, from SASOL Germany GmbH of Uberseering 40, 22297 Hamburg, Germany was modified with silicon such that the final silicon level was between 0 to 1.9 mass % Si/g of support. A cobalt nitrate containing precursor was prepared by slurry impregnation. 15 kg of the above mentioned silica modified gamma alumina support was impregnated with a solution of 15 kg distilled water, 11.9 kg of Co(NO.sub.3).sub.2.6H.sub.2O and 7.44 g of Pt(NH.sub.3).sub.4(NO.sub.3).sub.2. The temperature of this slurry was increased to 60 C. after which a pressure of 20 kPa(a) was applied. During the first 3 hours of the drying step, the temperature was increased slowly and reached 95 C. after 3 hours. After 3 hours the pressure was decreased to 3-15 kPa(a), and a drying rate of 2.5 m %/h at the point of incipient wetness was used. The complete impregnation and drying step took 9 hours, after which the treated uncalcined cobalt nitrate containing precursor was unloaded. This precursor was calcined as described below.

(64) Second impregnation to obtain a precursor with 30 g Co/100gSupport (Example 11B)

(65) 10 kg of the calcined cobalt oxide containing precursor was used to prepare the precursor containing 30 g Co/100 g Support. The calcined precursor was impregnated with a solution of 7.5 kg distilled water, 5.7 kg of Co(NO.sub.3).sub.2.6H.sub.2O and 8.15 g of Pt(NH.sub.3).sub.4(NO.sub.3).sub.2, and dried under increased temperature and vacuum. The temperature of this slurry was increased to 60 C. after which a pressure of 20 kPa(a) was applied. During the first 3 hours of the drying step, the temperature was increased slowly and reached 95 C. after 3 hours. After 3 hours the pressure was decreased to 3-15 kPa(a), and a drying rate of 2.5 m %/h at the point of incipient wetness was used. The complete impregnation and drying step took 9 hours, after which the treated uncalcined precursor containing cobalt nitrate was unloaded. This precursor was calcined as described below.

(66) Calcination of Dried Cobalt Nitrate Containing Precursor

(67) The uncalcined cobalt nitrate containing precursor was calcined in a TORBED reactor (fluidised bed reactor) by loading the cobalt nitrate containing precursor batch into the feeder hopper. The temperature of the TORBED reactor (fluidised bed reactor) was set at 270 C., the air flow was set at 75 m3.Math.h.sup.1 and the vibrator feeder speed was set at 10 kg. h.sup.1. After the temperature had stabilized, the valve to the vibrator feeder was opened and the cobalt nitrate precursor (at room temperature) was fed by vibration into the TORBED reactor (fluidised bed reactor). The heating rate for the precursor was 77 C./min up to 255 C., while the space velocity was 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour (i.e. high heating rate period). Thereafter the precursor was treated for about 14 minutes in the TORBED reactor (fluidised bed reactor), while the temperature increased from 255 C. to 270 C., with a heating rate of 1.1 C./min and a space velocity of 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour.

(68) The resultant cobalt-based Fischer-Tropsch synthesis catalyst precursor was unloaded from the reactor hopper and cyclone hopper.

EXAMPLE 12 (INVENTIVE) (TORBED REACTOR (FLUIDISED BED REACTOR) CALCINER EXAMPLE C1118/1 T)

(69) The calcination in this example was executed by means of 2 high and 1 low heating rate periods in a TORBED reactor (fluidised bed reactor), all in the 90 to 220 C. range.

(70) A particulate supported cobalt-based Fischer-Tropsch synthesis catalyst precursor, which, on activation, produces a 16 g Co/100 g Al.sub.2O.sub.3 proprietary slurry phase Fischer-Tropsch synthesis catalyst of the Applicant, was investigated.

(71) Cobalt Impregnation

(72) The precursor of this example was prepared in a similar manner to that of Example 11, first impregnation only, to obtain a precursor with 16 g Co/100 g Support. The uncalcined precursor was calcined as follows:

(73) Calcination of Cobalt Nitrate Containing Precursor (or Loaded Catalyst Support)

(74) The precursor was calcined in a TORBED reactor (fluidised bed reactor) by loading the cobalt nitrate containing precursor batch into the feeder hopper. The temperature of the TORBED reactor (fluidised bed reactor) was set at 150 C., the air flow was set at 75 m3.Math.h.sup.1 and the vibrator feeder speed was set at 10 kg.Math.h.sup.1. After the temperature had stabilized, the valve to the vibrator feeder was opened and the partially calcined cobalt nitrate containing precursor (at room temperature) was fed by vibration into the TORBED reactor (fluidised bed reactor). The heating rate for the precursor was 39 C./min (i.e. high heating rate period) up to 141 C., while the space velocity was 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour. Thereafter the precursor was treated for about 11 minutes in the TORBED reactor (fluidised bed reactor), while the temperature increased from 141 C. to 150 C., with a heating rate of 0.8 C./min (i.e. low heating rate period) and a space velocity of 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour.

(75) The resultant partially calcined cobalt nitrate containing precursor was unloaded from the reactor hopper and cyclone hopper, and loaded into the feeder hopper of the TORBED reactor (fluidised bed reactor). The temperature of the TORBED reactor (fluidised bed reactor) was set at 250 C., the air flow was set at 75 m3.Math.h.sup.1 and the vibrator feeder speed was set at 10 kg.Math.h.sup.1. After the temperature had stabilized, the valve to the vibrator feeder was opened and the cobalt nitrate precursor (at room temperature) was fed by vibration into the TORBED reactor (fluidised bed reactor). The heating rate for the precursor was 70 C./min up to 240 C., while the space velocity was 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour (i.e. high heating rate period). Thereafter the precursor was treated for about 10 minutes in the TORBED reactor (fluidised bed reactor), while the temperature increased from 240 C. to 250 C., with a heating rate of 1 C./min and a space velocity of 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour. The resultant particulate supported cobalt-based Fischer-Tropsch synthesis catalyst precursor was unloaded from the reactor hopper and cyclone hopper.

EXAMPLE 13 (INVENTIVE) (TORBED REACTOR (FLUIDISED BED REACTOR) CALCINER EXAMPLE C1149/2 T)

(76) The calcination in this example was executed by means of 3 high and 2 low heating rate periods in a TORBED reactor (fluidised bed reactor), all in the 90 C. to 220 C. range.

(77) A particulate supported cobalt-based Fischer-Tropsch synthesis catalyst precursor, which, on activation, produces a 30 g Co/100 g Al.sub.2O.sub.3 proprietary slurry phase Fischer-Tropsch synthesis catalyst of the Applicant, was investigated.

(78) Cobalt Impregnation

(79) The precursor of this example was prepared in a similar manner to that of Example 11, first and second impregnations, to obtain a precursor with 30 g Co/100 g Support. The uncalcined precursor was calcined as follows:

(80) Calcination of dried cobalt nitrate containing precursor (or loaded catalyst support) Calcination after the first impregnation in the TORBED reactor (fluidised bed reactor) was performed in a similar manner to Example 1. Calcination after the second impregnation was performed as follows:

(81) The precursor was calcined in a TORBED reactor (fluidised bed reactor) by loading the cobalt nitrate containing precursor batch into the feeder hopper. The temperature of the TORBED reactor (fluidised bed reactor) was set at 100 C., the air flow was set at 75 m3.Math.h.sup.1 and the vibrator feeder speed was set at 10 kg.Math.h.sup.1. After the temperature had stabilized, the valve to the vibrator feeder was opened and the cobalt nitrate precursor (at room temperature) was fed by vibration into the TORBED reactor (fluidised bed reactor). The heating rate for the precursor was 22 C./min (i.e. high heating rate period) up to 92 C., while the space velocity was 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour. Thereafter the precursor was treated for about 8 minutes in the TORBED reactor (fluidised bed reactor), while the temperature increased from 92 C. to 100 C., with a heating rate of 1 C./m in (i.e. low heating rate period) and a space velocity of 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour.

(82) The resultant partially calcined cobalt nitrate containing precursor was unloaded from the reactor hopper and cyclone hopper, and placed into the feeder hopper. The temperature of the TORBED reactor (fluidised bed reactor) was set at 130 C., the air flow was set at 75 m3.Math.h.sup.1 and the vibrator feeder speed was set at 10 kg.Math.h.sup.1. After the temperature had stabilized, the valve to the vibrator feeder was opened and the partially calcined cobalt nitrate containing precursor (at room temperature) was fed by vibration into the TORBED reactor (fluidised bed reactor). The heating rate for the precursor was 13 C./min (i.e. high heating rate period) up to 101 C., while the space velocity was 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour. Thereafter the precursor was treated for about 6 minutes in the TORBED reactor (fluidised bed reactor), while the temperature increased from 101 C. to 130 C., with a heating rate of 5 C./min (i.e. low heating rate period) and a space velocity of 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour.

(83) The resultant cobalt oxide precursor was unloaded from the reactor hopper and cyclone hopper, and placed into the feeder hopper. The temperature of the TORBED reactor (fluidised bed reactor) was set at 270 C., the air flow was set at 75 m3.Math.h.sup.1 and the vibrator feeder speed was set at 10 kg.Math.h.sup.1. After the temperature had stabilized, the valve to the vibrator feeder was opened and the cobalt nitrate precursor (at room temperature) was fed by vibration into the TORBED reactor (fluidised bed reactor). The heating rate for the precursor was 77 C./min up to 255 C., while the space velocity was 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour (i.e. high heating rate period). Thereafter the precursor was treated for about 14 minutes in the TORBED reactor (fluidised bed reactor), while the temperature increased from 255 C. to 270 C., with a heating rate of 1.1 C./m in and a space velocity of 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour. The resultant particulate supported cobalt-based Fischer-Tropsch synthesis catalyst precursor was unloaded from the reactor hopper and cyclone hopper.

EXAMPLE 14 (INVENTIVE) (TORBED REACTOR (FLUIDISED BED REACTOR) EXAMPLE C1212/2 T)

(84) The calcination in this example was executed by means of 3 high and 2 low heating rate periods in a TORBED reactor (fluidised bed reactor), all in the 90 to 220 C. range.

(85) A particulate supported cobalt-based Fischer-Tropsch synthesis catalyst precursor, which, on activation, produces a 30 g Co/100 g Al.sub.2O.sub.3 proprietary slurry phase Fischer-Tropsch synthesis catalyst of the Applicant, was investigated.

(86) The precursor was prepared and calcined in a similar manner to that of Example 1 to obtain a first impregnated and calcined cobalt oxide containing precursor.

(87) To obtain a precursor with 30 g Co/100 g Support prepared by incipient wetness impregnation, 10 kg of the calcined cobalt oxide containing precursor was used. 6.0 kg of Co(NO.sub.3).sub.2.6H.sub.2O and 7.6 g of Pt(NH.sub.3).sub.4(NO.sub.3).sub.2 was used to impregnate the calcined cobalt oxide containing precursor and stirred at 69 C. for 2 hours.

(88) Calcination of the cobalt nitrate and cobalt oxide containing precursor after the second impregnation was performed in similar fashion to the calcinations after second impregnation of Example 13.

EXAMPLE 15 (COMPARATIVE) (FLUIDISED BED CALCINED EXAMPLE C1441/1S)

(89) The calcination in this example was executed by means of 1 low heating rate period in a fluidised bed calciner, in the 90 to 220 C. range.

(90) A particulate supported cobalt-based Fischer-Tropsch synthesis catalyst precursor, which, on activation, produces a 16 g Co/100 g Al.sub.2O.sub.3 proprietary slurry phase Fischer-Tropsch synthesis catalyst of the Applicant, was investigated.

(91) Cobalt Impregnation

(92) The cobalt nitrate containing precursor was prepared in a similar manner to Example 10A. The precursor was prepared using the same Puralox modified support used for preparation of Example 6.

(93) Calcination of Dried Cobalt Nitrate Containing Precursor

(94) The dried precursor was loaded into a fluidised bed calcination unit. Calcination was performed at atmospheric pressure. The air flow was set at 2 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour. The temperature was increased by 1 C./m in from room temperature to 250 C. and held for 6 hours at 250 C. The calcined precursor was left to cool down to room temperature and unloaded.

EXAMPLE 16 (COMPARATIVE) (TORBED REACTOR (FLUIDISED BED REACTOR) CALCINER EXAMPLE C1871/1 S)

(95) The calcination in this example was executed by means of 3 high and 2 low heating rate periods in a TORBED reactor (fluidised bed reactor), all in the 90 to 220 C. range.

(96) This example was prepared and calcined in the same manner as Example 13, except that the space velocity was 4.0 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour during all the heating rate periods.

EXAMPLE 17 (INVENTIVE) (TORBED REACTOR (FLUIDISED BED REACTOR) CALCINER EXAMPLE C1209/1T (6))

(97) The calcination in this example was executed by means of 3 high and 2 low heating rate periods in a TORBED reactor (fluidised bed reactor), all in the 90 to 220 C. range.

(98) This example was prepared and calcined in the same manner as Example 13, except that the space velocity was 7.4 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour during all the heating rate periods.

EXAMPLE 18 (INVENTIVE) (TORBED REACTOR (FLUIDISED BED REACTOR) CALCINER EXAMPLE C1209/1T (11)

(99) The calcination in this example was executed by means of 3 high and 2 low heating rate periods in a TORBED reactor (fluidised bed reactor), all in the 90 to 220 C. range.

(100) This example was prepared and calcined in the same manner as Example 13, except that the space velocity was 13.8 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour during all the heating rate periods.

EXAMPLE 19 (INVENTIVE) (TORBED REACTOR (FLUIDISED BED REACTOR) CALCINER EXAMPLE C1209/1T (16)

(101) The calcination in this example was executed by means of 3 high and 2 low heating rate periods in a TORBED reactor (fluidised bed reactor), all in the 90 to 220 C. range.

(102) This example was prepared and calcined in the same manner as Example 13, including using a space velocity of 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour during all the heating periods.

EXAMPLE 20 (INVENTIVE) (TORBED REACTOR (FLUIDISED BED REACTOR)/FLUIDISED BED CALCINER EXAMPLE C1869/1 S)

(103) The calcination in this example was executed by means of 1 high and 1 low heating rate periods in a TORBED reactor (fluidised bed reactor), followed by 1 low heating period in a fluidised bed calciner, all in the 90 C. to 220 C. range.

(104) The cobalt nitrate containing precursor (or loaded catalyst support) of this example was prepared in a similar manner to that of Example 1.

(105) The Puralox support was modified with aqueous silicic acid and contained a higher Si load (1.9% Si) compared to Example 1 (1.3%).

(106) The calcination of the cobalt nitrate containing precursor was done as follows:

(107) Calcination of Cobalt Nitrate Containing Precursor

(108) The precursor was calcined in a TORBED reactor (fluidised bed reactor) by loading the cobalt nitrate containing precursor batch into the feeder hopper. The temperature of the TORBED reactor (fluidised bed reactor) was set at 150 C., the air flow was set at 75 m3.Math.h.sup.1 and the vibrator feeder speed was set at 10 kg.Math.h.sup.1. After the temperature had stabilized, the valve to the vibrator feeder was opened and the cobalt nitrate precursor (at room temperature) was fed by vibration into the TORBED reactor (fluidised bed reactor). The heating rate for the precursor was 39 C./min (i.e. high heating rate period) up to 141 C., while the space velocity was 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour. Thereafter the precursor was treated for about 11 minutes in the TORBED reactor (fluidised bed reactor), while the temperature increased from 141 C. to 150 C., with a heating rate of 0.8 C./min (i.e. low heating rate period) and a space velocity of 20 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour. The resultant partially calcined cobalt nitrate containing precursor was unloaded from the reactor hopper and cyclone hopper, and placed into the fluidised bed calciner.

(109) The partially calcined cobalt nitrate containing precursor was calcined in the fluidised bed calciner by loading the cobalt nitrate containing precursor batch into the fluidised bed calcinations unit. The temperature of the fluidised bed calciner was increased by 4 C./min from room temperature to 250 C. and the air flow was 2 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O/hour (i.e. low heating rate period). The resultant calcined cobalt oxide containing precursor, i.e. particulate supported cobalt-containing Fischer-Tropsch synthesis catalyst precursor, was left to cool to room temperature where after the material was unloaded.

EXAMPLE 21 (COMPARATIVE) (TORBED REACTOR (FLUIDISED BED REACTOR)/FLUIDISED BED CALCINER EXAMPLE C1752/1 S)

(110) The calcination in this example was executed by means of 1 high and 1 low heating rate periods in a TORBED reactor (fluidised bed reactor), followed by 1 high heating period (but only slightly above the heating rate required for a low heating rate period) in a fluidised bed calciner, all in the 90 C. to 220 C. range.

(111) The cobalt nitrate containing precursor (or loaded catalyst support) of this example was prepared in a similar manner to that of Example 1.

(112) The Puralox support was modified with aqueous silicic acid and contained a higher Si load (1.9% Si) compared to Example 1 (1.3%).

(113) The calcination of the cobalt nitrate containing precursor was effected in a similar fashion as in Example 20, except that the heating rate in the low heating rate period in the fluidised bed was 7 C./min instead of 4 C./min.

EXAMPLE 22 (XRD ANALYSES)

(114) The calcined samples from Examples 1-21 were subjected to a powdered X ray diffraction analysis as follows:

(115) The samples were packed into stainless steel holders. The Philips X'Pert Pro multi-purpose diffractometer (XRD-2 system) was used to do the analyses. Instrument settings were as follows: Tube voltage: 40 kV Tube current: 40 mA Source: Cobalt (wavelength 1.78897 ) Soller slit: 0.04 rad. Beam mask: 10 mm Automatic divergence slit Irradiated length: 10 mm Anti-scatter slit: 2 Filter: Iron Detector: X'Celerator Scan from: 5 2 Scan to: 105 2 Step size: 0.0167 2 Time per step: 150 s Scan duration: 2 hours

(116) X'Pert HighScore Plus software was used to identify the crystalline phases present in the sample. Topas was used for quantitative phase analysis using the fundamental parameter approach. The full pattern refinement technique was used to determine the average crystallite sizes. The sample adsorption was fixed at 10 cm.sup.1.

(117) The average crystallite sizes are listed in Tables 1, 2, 3, 4 and 5.

EXAMPLE 23 (FISCHER-TROPSCH TESTING)

(118) Some of the calcined catalyst precursor samples were subjected to a reduction or activation procedure as follows: In a fluidised bed (20 mm internal diameter) reduction unit, the calcined cobalt oxide containing precursor was reduced, at atmospheric pressure, utilizing an undiluted H.sub.2 reducing gas as total feed gas at a space velocity of 13.7 m.sup.3.sub.n per kilogram reducible cobalt per hour, whilst applying the following temperature program: heat from 25 C. to 425 C. at 1 C./min, and hold isothermally at 425 C. for 10 hours. After cooling down, the reduced catalyst was loaded into molten wax under an inert atmosphere to protect the sample from oxidizing. The precursor was thus thereby transformed into a corresponding catalyst.

(119) The reduced and wax coated catalyst sample was loaded in a micro slurry reactor and tested for Fischer-Tropsch synthesis performance using the following procedure: The catalyst was evaluated in a laboratory scale reactor under FTS conditions (230 C., 17.5 bar.sub.g pressure, H.sub.2:CO inlet ratio of 1.6:1 for catalysts and at synthesis gas conversions of 605%).

(120) The results are reported in Table 1.

EXAMPLE 24 (PSD ANALYSES)

(121) The particle size distribution of the catalyst precursor samples after the last calcination step was analyzed by means of a commercially available Saturn DigiSizer 5200. This was done for Examples 10A, 10B, 11A, 11B, 12, 13, 14, 20 and 21.

(122) The percentage of fine material smaller than 45 micron in the catalyst precursor is presented in Table 1 and Table 5.

(123) TABLE-US-00001 TABLE 1 Percentage of fines in catalyst precursor, Co.sub.3O.sub.4 crystallite size and relative FT activity for samples of the composition 30 gCo/0.075 gPt/1.3 gSi/100 gAl.sub.2O.sub.3(10B, 11B, 13, 14) and 16 gCo/0.075 gPt/1.3 gSi/100 gAl.sub.2O.sub.3 (10A, 11A, 12). Sample Fines <45 m Co.sub.3O.sub.4 Relative FT FT run Example No Name (%) () activity number 10A (comp) C1107/1 T 1.1 128 100 BJ049 11A (comp C742/1 T 12.4 88 12 (inv) C1118/1 T 4.3 60 114 BJ048 10B (comp) C1107/2 T 2.0 170 100 BJ052 11B (comp) C742/2 T 9.1 118 124 705F 13 (inv) C1149.2 T 2.5 100 131 BK057 14 (inv) C1212/2 T 1.1 120 143 CE044 (NOTE: The relative FT activities for Examples 10A and 12 are relative to that of Example 10A, while the relative FT activities for Examples 10B, 11B, 13 and 14 are relative to that of Example 10B.)
(NOTE: The relative FT activities for Examples 10A and 12 are relative to that of Example 10A, while the relative FT activities for Examples 10B, 11B, 13 and 14 are relative to that of Example 10B.)

(124) Table 1 shows that with the catalyst preparation process according to the invention a cobalt FT catalyst is produced that has an increased FT activity, smaller Co.sub.3O.sub.4 crystallites (i.e. in the catalyst precursor) with little breaking up the catalyst precursor in the calcination process. It also shows that in general an increased FT activity is accompanied by a decrease in the Co.sub.3O.sub.4 crystallite size.

(125) In more detail, comparative catalyst examples 10A and 10B, which were produced in a one step process with a low heating rate and low gas space velocity, showed that few catalyst fines were produced, however the catalyst activity of 100 was relatively low for both examples. A Co.sub.3O.sub.4 size for example 10A of 128 is large (i.e. for a 16 g Co/100 g Al.sub.2O.sub.3 catalyst) and compares well to the relatively low activity.

(126) Comparative catalyst example 11B, which was produced by a one step process with a high heating rate and a high gas space velocity, showed significantly improved catalyst activity of 124, while a large amount of catalyst fines was produced. Co.sub.3O.sub.4 sizes for examples 11A and 11B of 88 and 118 respectively are small (i.e. for a 16 g Co/100 g Al.sub.2O.sub.3 and 30 g Co/100 g Al.sub.2O.sub.3 catalyst respectively) and compares well to the relatively high activity.

(127) Inventive catalyst example 12 and 14, which were produced by a process using 2 high and 1 low heating rate periods, showed significantly improved catalyst activities of 114 and 143 respectively, and only a small amount of catalyst fines were produced. Co.sub.3O.sub.4 sizes for examples 12 and 14 of 60 and 120 respectively are small (i.e. for a 16 g Co/100 g Al.sub.2O.sub.3 and 30 g Co/100 g Al.sub.2O.sub.3 catalyst respectively) and compares well to the relatively high activity.

(128) Inventive catalyst example 13, which was produced by a process using 3 high and 2 low heating rate periods, showed a significantly improved catalyst activity of 131, and only a small amount of catalyst fines were produced. A Co.sub.3O.sub.4 size for example 13 of 100 is small (i.e. for a 30 g Co/100 g Al.sub.2O.sub.3 catalyst respectively) and compares well to the relatively high activity.

(129) TABLE-US-00002 TABLE 2 Co.sub.3O.sub.4 crystallite size for samples of the composition 16 gCo/0.04 gPt/1.3 gSi/100 gAl.sub.2O.sub.3 Example No Sample Name Co.sub.3O.sub.4 () 1 C1313/1 T 80 2 C1316/1 T 80 3 C1320/1 T 110 4 C1317/1 T 110 5 (comp) C1212/1 T 130 10A (comp) C1107/1 T 128

(130) Table 2 shows that with the catalyst preparation process according to the invention cobalt FT catalysts (i.e. examples 1-4) are produced that contain smaller Co.sub.3O.sub.4 crystallites (i.e. in the catalyst precursor). These Examples were all prepared by means of a process using a combination of at least one high and at least one low heating rate period. In the light of the observed relationship between Co.sub.3O.sub.4 crystallite size and FT activity in Table 1, the examples in Table 2 with smaller crystallites will also have increased FT activity.

(131) TABLE-US-00003 TABLE 3 Co.sub.3O.sub.4 crystallite size for samples of the composition 16 gCo/0.04 gPt/1.9 gSi/100 gAl.sub.2O.sub.3 Example No Sample Name Co.sub.3O.sub.4 () 6 C1338/1 S 140 7 C1339/1 S 110 8 C1342/1 S 140 9 C1343/1 S 120 15 (comp) C1441/1 S 150

(132) Examples 6-9 were all prepared by means of a process using a combination of at least one high and at least one low heating rate period. These examples resulted in a catalyst with a Co.sub.3O.sub.4 crystallite size of between 110 and 140 , which is smaller than the comparative example 15, which was prepared by means of a one step process. The smaller Co.sub.3O.sub.4 sizes will result in a catalyst with improved FT activity, while the combination of high and low heating rate periods will ensure that only few amounts of catalyst fines will be produced.

(133) TABLE-US-00004 TABLE 4 Co.sub.3O.sub.4 crystallite size for samples of the composition 16 gCo/0.04 gPt/1.9 gSi/100 gAl.sub.2O.sub.3 Example No Sample Name SV* Co.sub.3O.sub.4 () 16 (comp) C1871/1 S 4.0 120 17 C1209/1 T (6) 7.4 97 18 C1209/1 T (11) 13.8 99 19 C1209/1 T (16) 20 98 *SV is in m.sup.3.sub.n/kg Co(NO.sub.3).sub.26H.sub.2O/hour

(134) Table 4 shows that when using a space velocity of less than 5 m.sup.3.sub.n/kg Co(NO.sub.3).sub.2.6H.sub.2O)/hour, an undesired high cobalt crystallite size is obtained.

(135) TABLE-US-00005 TABLE 5 Co.sub.3O.sub.4 crystallite size for samples of the composition 16 gCo/0.04 gPt/1.9 gSi/100 gAl.sub.2O.sub.3 Sample HR Fines <45 m Example No Name SV* ( C./min) Co.sub.3O.sub.4 () (%) 20 C1869/1 S 2 4 140 1.5 21 (comp) C1752/1S 2 7 140 2.6 *SV is in m.sup.3.sub.n/kg Co(NO.sub.3).sub.26H.sub.2O/hour

(136) Table 5 shows that when the heating rate is in excess of 6 C./min for the low heating rate, the catalyst particle start to break-up: 2.6% fines compared to 1.5% fines for the sample with a heating rate of 4 C/m in.