Catalyst – solid sorbent – or support therefor: product or process – Zeolite or clay – including gallium analogs
Reexamination Certificate
1999-10-25
2001-02-27
Bell, Mark L. (Department: 1755)
Catalyst, solid sorbent, or support therefor: product or process
Zeolite or clay, including gallium analogs
C502S064000, C502S066000, C502S068000, C502S071000, C502S074000, C502S077000, C502S084000, C502S249000, C502S259000, C502S337000, C502S354000
Reexamination Certificate
active
06194337
ABSTRACT:
BACKGROUND OF INVENTION
I. Field of the Invention
The present invention relates to compositions for fluid catalytic cracking processes.
II. Description of the Prior Art
In an FCC process, metals accumulate onto the catalyst, the catalyst becomes deactivated with time and in order to maintain FCC unit activity, a fraction of the unit inventory is withdrawn and fresh catalyst is added. The spent catalyst (withdrawn catalyst) contains a dynamic mixture of catalyst particles from very old/high metals, low activity to newer/low metals high activity.
Antimony has frequently been added to cracking catalyst to “passivate” the catalyst and reduce the production of hydrogen and other undesirable light gaseous products, e.g., in U.S. Pat. Nos. 4,459,366, 4,457,693, 3,711,422, and 4,334,979.
Magnetic separation has been taught by a number of U.S. patents such as U.S. Pat. Nos. 4,406,773, 5,147,527, 5,106,486, 5,171,424, and 5,230,869 to Hettinger et al., which teaches the removal of inactive catalyst and sorbents from mixtures of active and inactive particulates so that the active particulates can be recovered for reuse.
However, it has not been previously taught that the passivating advantage of antimony on conversion on catalyst and sorbents can be coupled with the enhanced magnetic susceptible of metals to obtain the advantages of passivation and selective recovery of more active particulate.
SUMMARY OF THE INVENTION
I. General Statement of the Invention
Accordingly, the present invention provides a catalytic cracking catalyst comprising zeolite, kaolin, alumina and/or silica and 0.1-10 wt. % antimony [and 0.005-15wt. % antimony] and 100-5,000 wt. Ppm Ni, on an elemental metal basis.
Particularly preferred is a process as described above wherein at least a portion of the particulates in the mixture comprises iron, the combination of antimony plus iron having been found to have synergistic magnetic properties according to the discovery of the invention.
Also particularly preferred is a process in which at least a portion of the antimony is added by mixing in the feed so as to cause said antimony to deposit gradually over time onto the catalyst. (Sorbent may also be used according to the techniques of U.S. Pat. No. 4,237,312 in place of catalyst or intermixed with catalyst.)
The antimony can be included in the particulate catalyst or sorbent during the manufacture of the particulate; e.g. by compounding it, or by ion exchanging onto the surface of the catalyst, or dipping the catalyst into a solution or suspension of antimony compounds during manufacture of the catalyst or sorbent.
The invention is preferred for situations where the particulates are a high valued specialty catalyst or additive which it is desired to recover for recycle.
The invention embodies a system for the conversion of a metal containing hydrocarbon feed into lower molecular weight products comprising in combination: a) a source of antimony-containing moiety decomposable under FCC conditions; b) a contacting zone wherein said feed can be contacted with catalyst for hydrocarbon conversion purposes; c) a hydrocarbon feed which gradually exhausts the activity of said catalyst, over repeated contacts with said hydrocarbon feed; and d) a magnetic separator operably connected to separate at least a portion of said particulates after contact with said feed; said separators separating said particulates into at least a portion having a magnetic susceptibility greater than the average aforesaid mixture and at least a second portion having a magnetic susceptibility lower than the average aforesaid mixture.
Particularly preferred are compositions of matter comprising with one or more of zeolite, kaolin, alumina and/or silica and 0.1-10 wt. % antimony suitable for cracking hydrocarbon feedstocks containing nickel and/or iron.
Sb Compounds
Sb can be added to feed in the form of antimony acetate (a commercial 97% composition, is available); Nalco colloidal antimony compositions available from Nalco Chemical Co.; antimony pentoxide and the other antimony compounds described in the various patents of Phillips Petroleum Company; and any other compound of antimony which does not deleteriously affect the cracking process or the magnetic separation.
Sb Addition
As described above, the antimony can be impregnated into the catalyst during its manufacture, can be ion exchanged onto the surface of the catalyst before use, can be dipped or otherwise coated onto the surface before use, or can otherwise be present in virgin catalyst as it is introduced into the FCC or RCC cracking system. Amounts of antimony on catalyst are shown in Table III. The invention is useful with a wide variety of conventional catalyst and sorbents used for hydrocarbon conversion.
Antimony can be incorporated into a catalyst during manufacture in order to “tag” that particular catalyst. This is especially important when attempting to separate out and recover a particularly valuable catalyst, e.g. a ZSM-5 or other specialty catalyst or catalyst additive, as in U.S. Pat. No. 5,538,624. For example, if the ZSM-5 contains substantial amounts of catalyst, and if nickel accumulates along with iron on the surface of the catalyst during repeated cracking cycles, that ZSM-5-containing catalyst can readily be recovered by magnetic separation because of the high magnetic susceptibility imparted by the presence of all three metals in combination.
Alternatively, the Sb can be injected into the feed continuously or periodically or can be injected into the hot catalyst return line, or the recycle line from the magnetic separator back to the FCC unit.
Magnetic Separation
The magnetic separator can be of the HGMS type (high gradient magnetic separator), the RERMS type (rare earth roller magnetic separator), or other permanent magnet type, or electromagnetic magnets installed in roller-type magnetic separators, or can be of the electrostatic variety, as described in the text by Svoboda entitled
Magnetic Methods for the Treatment of Minerals.
II. Utility of the Invention
The present invention is useful for a wide variety of hydrocarbon conversion processes including, without limitation, fluid catalytic cracking, the RCC heavy oil conversion process, hydrotreating, catalytic reforming, and various sorbent processes such as the MRS™ process of Ashland Oil, Inc. The invention permits the separation of a high activity sorbent or catalyst or other particulate portion from a mixture comprising spent particles and active particles. The active portion can be recycled back to a contactor for contact with additional quantities of hydrocarbon feeds to be converted. Also, the invention permits the preferential removal of particularly high value or particularly specialized particles which have been added to a particle mixture for optimum conversion of the hydrocarbon feed.
REFERENCES:
patent: 3657155 (1972-04-01), Yoshino et al.
patent: 3686138 (1972-08-01), Yoshino et al.
patent: 4080395 (1978-03-01), Butter
patent: 4326993 (1982-04-01), Chester et al.
patent: 4877514 (1989-10-01), Hettinger et al.
patent: 4929583 (1990-05-01), Pasek et al.
patent: 5110775 (1992-05-01), Owen
patent: 5179054 (1993-01-01), Schipper et al.
Goolsby Terry L.
Mitchell Maurice M.
Bell Mark L.
Hailey Patricia L.
Marathon Ashland Petroleum LLC
Stone Richard D.
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