FISCHER-TROPSCH PROCESS USING REDUCED COBALT CATALYST

Abstract

A process for the conversion of a feed comprising a mixture of hydrogen and carbon monoxide to hydrocarbons, the hydrogen and carbon monoxide in the feed being present in a ratio of from 1:9 to 9:1 by volume, the process comprising the step of contacting the feed at elevated temperatures and atmospheric or elevated pressure with a catalyst comprising titanium dioxide and cobalt wherein the catalyst initially comprises from 30% to 95% metallic cobalt by weight of cobalt.

Claims

1-15. (canceled)

16. A process for the conversion of a feed comprising a mixture of hydrogen and carbon monoxide to hydrocarbons, the hydrogen and carbon monoxide in the feed being present in a ratio of from 1:9 to 9:1 by volume, the process comprising the step of: a. contacting the feed at elevated temperature and atmospheric or elevated pressure with a catalyst comprising titanium dioxide and cobalt; wherein the catalyst initially comprises from 30% to 95% metallic cobalt by weight of cobalt.

17. A process according to claim 16, further comprising the step of: i. pre-treating a catalyst composition comprising: a) titanium dioxide support, and b) oxidic cobalt or a cobalt compound decomposable thereto, with a reducing agent to form the catalyst employed in step a.

18. A process according to claim 16, wherein the catalyst initially comprises from 35% to 90%, preferably from 40% to 85%, and more preferably from 70% to 80% metallic cobalt by weight of cobalt.

19. A process according to claim 17, wherein the catalyst initially comprises from 35% to 90%, preferably from 40% to 85%, and more preferably from 70% to 80% metallic cobalt by weight of cobalt.

20. A process according to claim 17, wherein step i is conducted by exposing the catalyst composition to a hydrogen gas-containing stream, wherein the hydrogen gas-containing stream comprises less than 10% carbon monoxide gas by volume of carbon monoxide gas and hydrogen gas.

21. A process according to claim 17, wherein step i is conducted by exposing the catalyst composition to a carbon monoxide gas-containing stream, wherein the carbon monoxide gas-containing stream comprises less than 10% hydrogen gas by volume of carbon monoxide gas and hydrogen gas.

22. A process according to claim 16, wherein the mixture of hydrogen and carbon monoxide is in the form of synthesis gas, preferably wherein the synthesis gas comprises hydrogen gas and carbon monoxide gas at a ratio in the range of from 0.5:1 to 5:1 by volume, preferably in the range of from 1:1 to 3:1 by volume, more preferably in the range of from 1.6 to 2.2:1 by volume.

23. A process according to claim 16, wherein the catalyst comprises from 5% to 30%, preferably from 5% to 25% and more preferably from 10% to 20%, cobalt by weight of the catalyst.

24. A process according to claim 16, wherein the catalyst further comprises one or more promoters selected from chromium, nickel, iron, molybdenum, tungsten, manganese, boron, zirconium, gallium, thorium, lanthanum, cerium, ruthenium, rhenium, palladium, platinum, compounds and/or mixtures thereof.

25. A process according to claim 24, wherein the promoter is present in an amount of from 0% to 5%, preferably from 0.1% to 3%, and more preferably 0.5% to 2.5%, by weight of the catalyst.

26. A process according to claim 17, wherein the oxidic cobalt or a cobalt compound decomposable thereto is selected from cobalt(III) oxide, cobalt(II,III) oxide, cobalt(II) oxide, compounds decomposable thereto, or mixtures thereof.

27. A process according to claim 17, wherein the step of pre-treating the catalyst composition occurs at a temperature of from 200° C. to 300° C., preferably from 220° C. to 280° C., and more preferably from 230° C. to 250° C.

28. A Fischer-Tropsch catalyst comprising: i. titanium dioxide support, and ii. cobalt wherein the catalyst comprises from 30% to 95%, preferably from 35% to 90%, more preferably from 40% to 85%, and even more preferably from 70% to 80% of metallic cobalt by weight of cobalt.

29. A process for making a Fischer-Tropsch catalyst according to claim 28, comprising the step of: I. reducing a catalyst composition comprising: a) titanium dioxide support, and b) oxidic cobalt or a cobalt compound decomposable thereto, to produce the Fischer-Tropsch catalyst.

30. A product, preferably a fuel, comprising hydrocarbons obtained by a process according to claim 16.

Description

EXAMPLES

Examples 1-6

[0036] Cobalt oxide supported on titanium dioxide was manufactured as a catalyst by impregnating titanium dioxide powder with an aqueous solution of cobalt nitrate hexahydrate, followed by extrusion of the formed paste, and then drying and calcining to yield catalyst extrudates with a cobalt loading of 10% by weight of catalyst and a manganese loading of 1% by weight of catalyst. 0.25 g of the catalyst was loaded into the quartz u-tube reactor of a TPR unit and subjected to reduction under 100% hydrogen gas (at a GHSV of 3800 h.sup.−1) for 15 hours at the temperatures in Table 1 below. As described hereinabove, the degree of reduction was determined using TPR via comparison of the integrated areas of the TCD graphs of the samples against a standard that had been subject to TPR with no reduction step, in order to obtain the percentage hydrogen consumption, and calculation of the degree of reduction as percentage of Co present as Co.sup.0 using Equation 5 detailed hereinabove.

TABLE-US-00001 TABLE 1 Temperature Programmed Reduction (TPR) of cobalt oxide/manganese on titanium dioxide support Reduction Temperature Degree of Reduction Example (° C.) (% of Co as Co.sup.0) 1 No Pre-treatment 0 2 200 28 3 220 51 4 240 74 5 260 99 6 (comparative) 300 97

Examples 7-10

[0037] The catalyst sample was cobalt oxide on titanium dioxide support, 10 wt. % cobalt loading, 1 wt. % manganese loading. 9.6 g of catalyst sample was loaded into a metal liner of a multi-channel catalyst-screening microreactor. Each channel of the microreactor underwent the same drying procedure in parallel, before the catalysts were activated according to the following protocols under 100% H.sub.2 gas at a GHSV of 3800 h.sup.−1 and pressure of 1 atm:

Example 7 (comparative): From room temperature ramped to 150° C. at a rate of 2° C./min, then ramped to 200° C. at a rate of 1° C./min, before dwelling at 200° C. for 15 hours.
Example 8 (inventive): From room temperature ramped to 150° C. at a rate of 2° C./min, then ramped to 240° C. at a rate of 1° C./min, before dwelling at 240° C. for 15 hours.
Example 9 (comparative): From room temperature ramped to 150° C. at a rate of 2° C./min, then ramped to 260° C. at a rate of 1° C./min, before dwelling at 260° C. for 15 hours.
Example 10 (comparative): From room temperature ramped to 150° C. at a rate of 2° C./min, then ramped to 300° C. at a rate of 1° C./min, before dwelling at 300° C. for 15 hours.

[0038] The liners were then cooled, purged with nitrogen, and temperature ramped identically under a 1.8:1 H.sub.2:CO molar stream of syngas in 18% N.sub.2 at 30 barg total pressure at a GHSV of 1250 h.sup.−1. Each example was operated at a temperature of 201-214° C. in order to achieve the same level of conversion, under identical operating conditions with results presented in Table 2. The data for the inventive example shows acceptable selectivity to C.sub.5+ and CH.sub.4 alongside a similar temperature to reach the same CO conversion rate versus comparative examples 9 and 10, despite the milder reduction conditions leading to a lower degree of reduction. Example 8 also shows improved selectivity to C.sub.5+ and CH.sub.4 alongside a lower temperature to reach the same CO conversion rate versus example 7.

TABLE-US-00002 TABLE 2 Performance data of examples 7-10 in conversion of syngas to hydrocarbons Example 7 8 9 10 Pre-reduction Temperature (° C.) 200 240 260 300 GHSV (h.sup.−1) 1250 1250 1250 1250 Temperature (° C.) 214 201 200 198 CO Conversion (%) 67 65 65 65 C.sub.5+ Selectivity (%) 74.8 81.8 85.0 86.8 CH.sub.4 Selectivity (%) 15.0 10.8 8.9 7.4

Examples 11-13

[0039] The catalyst sample was cobalt oxide on titanium dioxide support, 10 wt. % cobalt loading, 2 wt. % manganese loading. Each catalyst sample (mass provided in Table 3) was loaded into a metal liner of a multi-channel catalyst-screening microreactor. Each channel of the microreactor underwent the same drying procedure in parallel, before the catalysts were activated according to the following protocols under 100% H.sub.2 gas at a GHSV 3800 h.sup.−1 and pressure of 1 atm:

From room temperature, ramped to 150° C. at a rate of 2° C./min, then ramped to 240° C. (example 11), 260° C. (example 12) or 300° C. (example 13) at a rate of 1° C./min, before dwelling at this final temperature for 15 hours.
The liners were then cooled, purged with nitrogen, and temperature ramped identically under a 1.8:1 H.sub.2:CO molar stream of syngas in 18% N.sub.2 at 30 barg total pressure and a GHSV of 1250 h.sup.−1. Each example was operated at a temperature of 195° C. under identical operating conditions with results presented in Table 3. The data for example 11 clearly shows improved selectivity to C.sub.5+ and similar selectivity to CH.sub.4 alongside similar temperatures to reach the same CO conversion rate versus the example 13, despite the milder reduction conditions leading to a lower degree of reduction, and even despite a lower mass of catalyst having been used, indicating improved activity.

TABLE-US-00003 TABLE 3 Performance data of examples 11-13 in conversion of syngas to hydrocarbons Example 11 12 13 Mass of Catalyst (g) 8.6 8.8 9.4 Pre-reduction 240 260 300 Temperature (° C.) GHSV (h.sup.−1) 1250 1250 1250 Temperature (° C.) 204 206 203 CO Conversion (%) 64 64 63 C.sub.5+ Selectivity (%) 83.7 81.0 82.5 CH.sub.4 Selectivity (%) 9.3 10.1 9.2

[0040] 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.”

[0041] 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.

[0042] 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.