FISCHER-TROPSCH PROCESS USING REDUCTIVELY-ACTIVATED 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 steps of: pre-treating a catalyst composition comprising titanium dioxide support and oxidic cobalt or a cobalt compound decomposable thereto, for a period of from 1 to 50 hours, with a hydrogen gas-containing stream comprising less than 10% carbon monoxide gas by volume of carbon monoxide gas and hydrogen gas, to form a reductively-activated catalyst; and contacting the feed at elevated temperature and atmospheric or elevated pressure with the reductively-activated catalyst; wherein the step of pre-treating the catalyst composition is conducted within a temperature range of from 200 C. to less than 300 C., preferably from 220 C. to 280 C., more preferably from 250 C. to 270 C.

Claims

1-16. (canceled)

17. 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 steps of: a. pre-treating a catalyst composition comprising: i. titanium dioxide support, and ii. oxidic cobalt or a cobalt compound decomposable thereto, for a period of from 1 to 50 hours, with a hydrogen gas-containing stream comprising less than 10% carbon monoxide gas by volume of carbon monoxide gas and hydrogen gas, to form a reductively-activated catalyst; and b. contacting the feed at elevated temperature and atmospheric or elevated pressure with the reductively-activated catalyst; wherein the step of pre-treating the catalyst composition is conducted within a temperature range of from 200 C. to less than 300 C., preferably from 220 C. to 280 C., more preferably from 250 C. to 270 C.

18. A process according to claim 17, wherein step a occurs for a period of from 5 to 35 hours, preferably from 7 to 20 hours, and even more preferably from 10 to 15 hours.

19. A process according claim 17, wherein the gas hourly space velocity (GHSV) of the hydrogen gas-containing stream in step a is in the range of from 100 to 10000 h-.sup.1, preferably from 250 to 5000 h-.sup.1, such as from 250 to 3000 h- and more preferably from 250 to 2000 h-.sup.1.

20. A process according to claim 17, wherein the step of pre-treating the catalyst composition is conducted within a temperature range of from 250 C. to less than 300 C., preferably from 250 C. to 280 C., more preferably from 250 C. to 270 C.

21. A process according to claim 17, wherein step a is carried out at a feed pressure of from 10 to 5500 kPa, preferably from 20 to 3000 kPa, more preferably from 50 to 1000 kPa, and even more preferably from 100 to 800 kPa.

22. A process according to claim 17, 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 17, wherein the catalyst composition and/or the reductively-activated 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 17, wherein the catalyst composition and/or the reductively-activated 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 24, wherein the promoter is manganese and is present in an amount of from 0.5% to 2.5%, preferably from 1% to 2.5% and more preferably from 1.5% to 2.25%.

27. A process according to claim 24, wherein the promoter is manganese and is present in an amount of from from 0.1% to 1.5%, preferably from 0.5% to 1.5%, more preferably from 0.75% to 1.25% and even more preferably from 0.8% to 1.2%.

28. 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.

29. A product, preferably a fuel, comprising hydrocarbons obtained by a process according to claim 17.

30. A process for making a Fischer-Tropsch catalyst comprising the step of: c. treating a catalyst composition comprising: i. titanium dioxide support, and ii. oxidic cobalt or a cobalt compound decomposable thereto, for a period of from 1 to 50 hours, with a hydrogen gas-containing stream comprising less than 10% carbon monoxide gas by volume of carbon monoxide gas and hydrogen gas, to form the Fischer-Tropsch catalyst, wherein the step of pre-treating the catalyst composition is conducted within a temperature range of from 200 C. to less than 300 C., preferably from 220 C. to 280 C., more preferably from 250 C. to 270 C.

31. A Fischer-Tropsch catalyst produced by the process of claim 30.

Description

EXAMPLES

Examples 1-4

[0029] 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. The catalyst sample was thus 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 1 (inventive): 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 2 (Inventive)

[0030] 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 3 (Inventive)

[0031] 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 4 (Comparative)

[0032] 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.

[0033] 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 1. 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 example 4, despite the milder reduction conditions. Example 3 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 2. Furthermore, Example 3 actually demonstrates a relatively small loss of C5+ selectivity versus example 4 despite a 40 C. drop in activation temperature, while a much more significant loss of C5+ selectivity is seen between example 3 and example 2 with only a 20 C. drop in activation temperature. This steeper loss of C5+ selectivity is then maintained to example 1.

TABLE-US-00001 TABLE 1 Performance data of examples 1-4 in conversion of syngas to hydrocarbons Example 1 2 3 4 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 5-7

[0034] 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 2) 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:

[0035] From room temperature, ramped to 150 C. at a rate of 2 C./min, then ramped to 240 C. (example 5), 260 C. (example 6) or 300 C. (example 7, comparative) at a rate of 1 C./min, before dwelling at this final temperature for 15 hours.

[0036] 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 5 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 example 7, 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. Similarly, example 6 provides comparable performance to example 7 despite less catalyst having been used.

TABLE-US-00002 TABLE 2 Performance data of examples 5-7 in conversion of syngas to hydrocarbons Example 5 6 7 Mass of Catalyst (g) 8.6 8.8 9.4 Pre-reduction Temperature ( C.) 240 260 300 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

[0037] 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.

[0038] 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.

[0039] 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.