Claims
- 1. A process for treating a spent hydrotreating catalyst comprising shaped, generally cylindrical, regular geometric particles having substantially the same diameter, varying length and an L/D greater than one, said particles having carbonaceous and metallic deposits resulting from a hydrocarbon feedstock which process comprises
- passing said particles to a length grading zone comprising a rotating cylindrical drum having inwardly opening indentations in a cylindrical wall thereof, the indentations having a transverse diameter L.sub.1 in the range of 0.8 to about 24 millimeters;
- rotating said drum about a longitudinal axis thereof at a speed sufficient to entrap in the indentations and convey particles having a length below L.sub.1 upwardly to a height permitting the particles to fall into a fixed upwardly opening trough, while retaining particles having a length above L.sub.1 in a bottom portion of said drum; conveying the particles in the trough out a first outlet; whereby at last about 80 percent of said particles with a length less than L.sub.1 are separated from the desired particles which ave a length greater than L.sub.1 ; said particles having a length greater than L.sub.1 comprising relatively uncontaminated particles and heavily contaminated particles;
- conveying the particles in the bottom of the said drum out a second outlet, separate from said first outlet to a density grading zone in which said relatively uncontaminated particles are suspended in a gas above said heavily contaminated particles, said heavily contaminated particles are caused to move upwardly along an inclined, vibrating surface and are thereafter collected at a first density grading zone outlet, said relatively uncontaminated particles contact a lower portion of said vibrating surface and are collected at a second density grading zone outlet, withdrawing said relatively uncontaminated particles from a third density grading zone outlet and passing said relatively uncontaminated catalyst particles to a hydrotreating zone, and contacting a hydrocarbon feedstock under hydrotreating conditions.
- 2. The process of claim 1 wherein prior to passing said particles to said length grading zone, said particles are passed to a regeneration zone and carbon deposits are removed from the surface of said particles.
- 3. The process of claim 1 wherein said catalyst comprises particles having an L/D greater than 1, but less than 2.0.
- 4. The process of claim 1, wherein said catalyst comprises particles rendered free flowing by treatment with an inert stripping gas while heating.
- 5. The process of claim 1 wherein said catalyst comprises particles containing active catalytic metals from the group of cobalt, nickel, molybdenum, titanium or tungsten on a refractory metal oxide support.
- 6. The process of claim 1 wherein said catalyst comprises pelletized or extruded alumina, silica-alumina, silica, molecular sieves or combinations thereof.
- 7. The process of claim 1 where L.sub.1 is in the range of from about 0.8 to about 6 millimeters.
- 8. The process of claim 2 wherein said regenerated catalyst particles are contacted with a leaching acid to remove heavy metals.
- 9. The process of claim 1 wherein said relatively uncontaminated catalyst-type particles are contacted with oxygen under regeneration conditions.
- 10. The process of claim 1 wherein said catalyst particles comprise a mixture of a supported catalyst and the support of said catalyst.
Parent Case Info
This is a continuation of application Ser. No. 06/837,690 filed Mar. 10, 1986, now abandoned. U.S. Pat. No. 4,720,473 to Welch et al is a division of application Ser. No. 06/837,690, now abandoned.
US Referenced Citations (39)
Foreign Referenced Citations (1)
Number |
Date |
Country |
223639 |
May 1987 |
EPX |
Non-Patent Literature Citations (9)
Entry |
Carter Day Uni-Flow Cylinder (8 pages). |
Triple/s Dynamics--Dry Separations for the Processing Industries (12 pages). |
Triple/s Dynamics--V-135D & V-135E Fluidized-Bed Separator (2 pages). |
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Continuations (1)
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Number |
Date |
Country |
Parent |
837690 |
Mar 1986 |
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