Process for the preparation of a catalyst based on cobalt and sc

Details Process for the preparation of a catalyst based on cobalt and sc Process for the preparation of a catalyst based on cobalt and sc

1999-03-18

2000-08-01

Richter, Johann

Chemistry: fischer-tropsch processes; or purification or recover

Group viii metal containing catalyst utilized for the...

518700, 502263, 502314, 502327, C07C 2700, B01J 2108, B01J 2300, B01J 2340

Patent

active

060967900

DESCRIPTION:

BRIEF SUMMARY
The present invention relates to a process for the preparation of a catalyst and its use in the conversion of synthesis gas according to the Fischer-Tropsch process.
More specifically, the present invention relates to a process for the preparation of a catalyst comprising Co and Sc supported on an inert carrier.
The selection of cobalt is due to the fact that this favours the formation of paraffins with a high molecular weight preventing the formation of branched products, olefins and compounds containing oxygen.
The use of catalysts based on cobalt goes back to the first works of Fischer in 1932 (H. H. Storch, N. Golumbic, R. B. Anderson, "The Fischer Tropsch and Related Synthesis", John Wiley & son, Inc., New York, 1951, pages 345-367) which developed the Co/ThO.sub.2 /Mg0/kieselguhr system.
The evolution of these systems subsequently led to the idenfitication of various promoters to be coupled with cobalt in order to increase the selectivity to hydrocarbons with a high moleuclar weight, this mainly in the last twenty years. In fact, the increase in price of crude oil in the 70s' provided the incentive for exploring other ways of producing liquid fuels and chemicals.
U.S. Pat. No. 4,088,671 describes a catalyst for Fischer-Tropsch having cobalt and ruthenium as active ingredients, the former being present in a larger quantity with respect to the latter.
WO93/05000 describes a catalyst essentially consisting of cobalt (1-50% by weight), scandium (0.01-25% by weight) and an appropriate carrier selected from alumina, silica, silica-alumina, kieselguhr, prepared according to the usual preparation techniques among which impregnation of the carrier with aqueous solutions of the corresponding salts. The above catalyst, particularly efficient in the conversion of synthesis gas to give a hydrocarbon product with a high content of paraffins, has the disadvantage however of requiring high reaction temperatures and producing large quantities of methane.
A process has been found for the preparation of a catalyst, supported on an inert material, essentially consisting of a larger quantity of cobalt and a smaller quantity of scandium, which overcomes the drawbacks mentioned above. With this process, in fact, it is possible to obtain a supported catalyst based on cobalt and scandium which allows high conversions of CO to paraffins with a high molecular weight with low selectivities to methane, operating at lower temperatures than those described in WO 93/05000.
In accordance with this, the present invention relates to a process for the preparation of a catalyst comprising an inert carrier selected from at least one oxide of at least one element selected from Si, Ti, Al, Zr, Zn, Mg, Sn, preferably silicon, in the form of elements or oxides, a larger quantity of cobalt and smaller quantities of scandium, characterized in that it comprises at least the following steps: least part of the inert carrier, by the deposition of cobalt on the inert carrier; subsequent calcination, reduction and passivation of the inert carrier containing cobalt; catalytic precursor (A); subsequent calcination, reduction and passivation of the inert carrier containing cobalt and scandium.
A further object of the present invention relates to the catalyst which can be obtained with the above process.
In the process of the present invention, step (1) consists in an initial deposition of cobalt on the inert carrier. This deposition, like that of the second element in step (2), can be carried out according to various techniques known to experts in the field, for example exchange, impregnation, dry impregnation (also called of the incipient imbibition), precipitation, gelation and mechanical mixing.
In the preferred embodiment, the deposition of cobalt in step (1) is carried out by the dry impregnation technique. According to this method the material to be impregnated is put in contact with a volume of solution more or less equal to the pore volume.
In step (1) it is preferable to use aqueous solutions of cobalt salts. Any kind of cobalt salts can be us

REFERENCES:
patent: 4585798 (1986-04-01), Beuther et al.
patent: 5856365 (1999-01-01), Zennaro et al.

Affiliated with

Also associated with

Rating

Process for the preparation of a catalyst based on cobalt and sc does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Process for the preparation of a catalyst based on cobalt and sc, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for the preparation of a catalyst based on cobalt and sc will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-664550