US3546103A - Hydrogenation catalysts on charcoal in guard chamber for removing metals from petroleum residua - Google Patents

Description

United States Patent O 3,546,103 HYDROGENATION CATALYSTS ON CHARCOAL IN GUARD CHAMBER FOR REMOVING METALS FROM PETROLEUM RESIDUA Glen P. Hamner, Baton Rouge, and Ralph B. Mason, Denham Springs, La., assiguors to Esso Research and Engineering Company, a corporation of Delaware No Drawing. Filed Feb. 3, 1969, Ser. No. 796,213 Int. Cl. Cg 23/02, 31/14 U.S. Cl. 208-211 9 Claims ABSTRACT OF THE DISCLOSURE Metals and coke precursors are removed from petroleum residua prior to hydrodesulfurization by contacting the residua with a hydrodesulfurization catalyst supported on charcoal or activated carbon so that the metals may be easily recovered by gasifying or burning the carbon base.

BACKGROUND OF THE INVENTION This invention relates to a method for the removal of metals and coke precursors from heavy feeds to a hydrodesulfurization process.

The higher boiling fractions of crude petroleum often contain traces of vanadium, nickel and other metals which cause rapid deactivation of sulfur resistant catalysts used in the hydrodesulfurization of such fractions. This is particularly true of residuum fractions as a result of which it has not been practical to refine such fractions by a catalytic hydrodesulfurization process.

It has previously been suggested that metals be removed from feeds to a hydrodesulfurization process by first contacting the feedstock with bauxite in the presence or absence of hydrogen under conditions of temperature and pressure such that the metals are deposited on the bauxite as described in U.S. Pats. 2,687,985, filed Jan. 22, 1953, to Porter and Purdy and 2,769,758 filed Mar. 13, 1952, to Porter and Isitt. The use of titania on alumina for the same purpose is described in U.S. Pat. 2,730,487 filed July 1, 1953, to Porter and Purdy.

It is also known to remove asphaltenes as well as metals from a reduced crude prior to desulfurizing the same, by contacting the reduced crude in the presence of hydrogen with a catalyst similar to that used in the subsequent desulfurization stage or with an essentially inert particulate contact material such as tabular alumina, electrician beads, extruded alumina or a low activity catalyst as described in U.S. Pat. 3,362,901 to Szeppe et al., filed I an. 11, 1966, and issued Jan. 9, 1968.

While the above processes are successful in removing metals from heavy petroleum fractions, nevertheless it has been found somewhat diificult to remove the metals from the bauxite, alumina or other supports used in the preliminary treating zone.

SUMMARY OF THE INVENTION In accordance with the present invention the above disadvantages are overcome by first contacting the feedstock in a guard chamber containing a hydrodesulfurization catalyst supported on a charcoal or activated carbon base at elevated temperature and pressure in the presence of hydrogen so that a considerable proportion of the metals and coke precursors are deposited thereon and thereafter passing the thus treated feedstock to a hydrodesulfurization zone under generally more severe conditions than prevails in the first stage whereby the activity of the catalyst is increased and the catalyst life is extended because of reduced metal deposition. In one embodiment the charcoal base can be easily removed by burning or steam gasification to form desirable gas products leaving 3,546,103 Patented Dec. 8, 1970 DESCRIPTION OF THE PREFERRED EMBODIMENTS The charcoal or activated carbon base suitable for use in this invention may be any solid type of carbon capable of supporting metallic catalyst. However it is preferred to use activated carbon which is made by the destructive distillation of carbonaceous material under controlled conditions. The specific area of such a carbon may range from 600 to 2000 square meters per gram.

Any type of sulfactive hydrogenation catalyst may be used in conjunction with the charcoal or activated carbon base. Suitable catalysts include one or more of the oxides or sulfides of a metal of Group VIII in combination with metals of Group II-B and VI-B, such as Ni-W, Ni-Mo, Co-Mo, Co-W, Zn-Mo, Zn-W or mixtures thereof. A typical catalyst contains about 0.1 to 20% by weight of a Group VIII metal such as nickel and about 0.1 to 20% by weight of a Group VI-B metal such as tungsten.

The reaction conditions used in the first stage can vary over wide ranges depending on the particular feed. Generally the conditions include pressures of from about 500 to 1500 p.s.i.g., a temperature of about 650 to 950 F., a feed rate of 0.5 to 20 volumes of feed per volume of catalyst per hour (v./v./hr.) and 1000 to 10,000 s.c.f. per barrel of hydrogen.

The subsequent hydrodesulfurization reaction is accomplished over catalysts which are preferably more active than those used for the preliminary treatment. The active metallic components in the catalyst are a Group VI-B oxide or sulfide, specifically an oxide or sulfide of molybdenum, tungsten, or their mixtures and a Group VIII metal oxide or sulfide, specifically an oxide or sulfide of nickel or cobalt. Suitable catalysts consist of 1 to 15 wt. percent of nickel or cobalt (as oxide) preferably 2 to 10 wt. percent, 5 to 25 wt. percent of tungsten or molybdenum (as oxide), preferably 10 to 20 wt. percent supported on alumina, the alumina preferably containing 1 to 6 wt. percent of silica. A particularly suitable catalyst consists of 3.5 wt. percent of C00" and 12.5 wt. percent M00 on alumina containing about 2.0 wt. percent silica and having a maximum surface area in pores having a diameter of 30 to 70 A. as described in application Ser. No. 648,604 filed June 26, 1967, which was issued as U.S. Patent 3,509,044 on April 28, 1970, to Adams and House and the subject matter of which is incorporated herein by reference.

The reaction conditions in the hydrodesulfurization step may range between 500-825 F., preferably 650-800, 500-2500 p.s.i.g., preferably 800-1800 p.s.i.g., a space velocity of 0.2 to 5.0 v./v./hr., preferably 0.5-2.0, and a hydrogen rate of 500-7500 s.c.f. per barrel, preferably 1000-5000.

The feed stock is preferably a petroleum residium 30 to of which boils above 900 F. and which is obtained from crude oils by distillation or treating or by some other type of separation. The residuum may be a blend of high boiling materials such as atmospheric bottoms, vacuum bottoms, deasphalted oil visbreaker bottoms, gas oil cuts and the like. All of these materials contain about 25 p.p.m. or more each of nickel or vanadium measured as the oxides NiO and V 0 The following example is included to illustrate the effectiveness of the instant process for the preliminary 3 treatment of petroleum residuum prior to hydrodesulfurization thereof without limiting the same.

EXAMPLE Three runs were carried out using West Texas residuum and Bachaquero residuum as feed. In each case the feed was passed over a nickel-tungsten catalyst (2.3% Ni and 11.4% W) on activated charcoal at a temperature of 800 F., 1000 p.s.i.g., 1 v./v./hr. at a 5000 s.c.f. of H per barrel gas rate. The metals were recovered by burning the charcoal and recovering the metals from the ash.

The following data were obtained.

Bacliaquero West Texas Feed 400 F. Feed Run No Prod. Distr Feed F 08d CO and CO2 0.8 0.4 0.5 1.7 1.1 1.9 0.7 0.7 0.8 100 97. 0 97. 8 100 96. 8

ct on Gravity, API 18. 3 29. 3 25. 5 15. 2 24. 7 Sulfur, wt. percent 2. 2 0. 0. 64 2. 4 0. 55 6. 0 0. 8 2. 5 10. 5 3. 4 24 l 1 400 56 12 1 1 57 12 Wt. percent on feed (output basis).

The above data show that metal removal from the pretreatment was excellent 1 ppm.) with West Texas residuum and satisfactory with the high-metal content Bachaquero residuum 70 p.p.m.). The Conradson carbon level of both feed stocks was reduced considerably, indicating the removal of coke precursors. Furthermore more than 60% desulfurization was realized. Substantially complete desulfurization can thus be obtained in a second stage conventional hydrodesulfurization step using cobalt molybdate catalyst with high catalyst activity maintenance level for a long period of time due to the previous removal of metals from the feed.

The nature of the present invention having thus been fully set forth and specific examples of the same given, what is claimed as new, useful, and unobvious and desired to be secured by Letters Patent is:

1. A process for the removal of metals and coke precursors from a hydrocarbon residuum containing the same which comprises contacting said residuum at 65095 0 E, 500-1500 p.s.i.g., a feed rate of 0.5 to volumes of residuum per volume of catalyst per hour and in the presence of 1000 to 10,000 standard cubic feet of hydrogen per barrel of feed and a catalyst comprising an oxide or sulfide of a metal of Group II-B or VI-B together with a Group VIII metal on charcoal for a period of time to remove a substantial quantity of the metals.

2. The process of claim 1 in which the catalyst is nickel oxide and tungsten oxide on charcoal.

3. The process of claim 2 in which the catalyst contains 2.3 wt. percent Ni and 11.4 wt. percent W.

4. A process for the two-stage treatment of a hydrocarbon residuum containing a substantial quantity of metals and coke precursors which comprises pretreating said residuum in a first stage with a contact material comprising an oxide or sulfide of a metal of Group II or VI- B together with a Group VIII metal on charcoal at 650 950 F., 500-1500 p.s.i.g., a feed rate of 0.5 to 20 volumes of feed per volume of catalyst per hour and in the presence of 1000 to 10,000 standard cubic feet of hydrogen per barrel of feed for a period of time to remove a substantial quantity of the metals and coke precursors and subsequently contacting the thus pretreated feed in a second stage with a hydrodesulfurizing catalyst comprising an oxide or sulfide of a Group VI-B and a Group VIII metal on alumina at a temperature of 500-825 F., a pressure of 500-2500 p.s.i.g., a space velocity of 0.2 to 5.0 v./v./hr. and a hydrogen rate of 500-7500 s.c.f./bbl.

5. The process of claim 4 in which the second stage catalyst is 1020 wt. percent molybdenum oxide and 2- 20 wt. percent cobalt oxide on alumina containing l-6 wt. percent silica.

6. The process of claim 5 in which the alumina has a maximum surface area in pores having a diameter of 30- A.

7. The process of claim 4 in which the metals are removed from the first stage catalyst by burning.

8. The process of claim 4 in which the catalyst of the first stage is regenerated by partial oxidation.

9. The process of claim 4 in which the catalyst of the first stage is regenerated by steam gasification.

References Cited UNITED STATES PATENTS 2,687,985 8/1954 Porter et al 208211 2,755,225 7/1956 Porter et al 208-211 2,766,183 10/1956 Porter et al. 208-211 2,987,467 6/1961 Keith et a1. 208-211 3,367,862 2/1968 Mason et al. 208-253 FOREIGN PATENTS 282,513 3/1965 Australia. 682,387 11/1952 Great Britain.

DELBERT E. GANTZ, Primary Examiner G. I. CRASANAKIS, Assistant Examiner US. Cl. X.R.