Methods of regenerating aromatization catalysts

Patent metadata

Field	Value
Publication number	US-9943837-B2
Application number	US-201414230373-A
Country	US
Kind code	B2
Filing date	Mar 31, 2014
Priority date	Mar 5, 2012
Publication date	Apr 17, 2018
Grant date	Apr 17, 2018

Abstract

Methods for treating or rejuvenating a spent catalyst are disclosed. Such methods can employ a step of halogenating the spent catalyst, followed by decoking the halogenated spent catalyst.

First claim

That which is claimed is:

1. A method of treating a spent catalyst comprising a transition metal and a catalyst support, the method comprising:
(1) contacting the spent catalyst with a halogen-containing stream to produce a halogenated spent catalyst, wherein the halogen-containing stream comprises from about 250 to about 5000 ppmv of a chlorine-containing compound and from about 250 to about 5000 ppmv of a fluorine-containing compound;
(2) contacting the halogenated spent catalyst with a purging stream consisting essentially of an inert gas; and
(3) contacting the halogenated spent catalyst with a decoking gas stream comprising oxygen.

2. The method of claim 1 , wherein the halogen-containing stream comprises Cl 2 , F 2 , and nitrogen, and is substantially free of oxygen-containing compounds.

3. The method of claim 2 , wherein:
step (1) is conducted at a halogenation temperature in a range from about 120° C. to about 320° C.; and
a molar ratio of Cl:F in the halogen-containing stream is in a range from about 0.2:1 to about 10:1.

4. The method of claim 1 , wherein the spent catalyst comprises:
platinum on a KL-zeolite;
a support matrix comprising alumina, silica, a mixed oxide thereof, or a mixture thereof;
from about 0.025 wt. % to about 5 wt. % chlorine; and
from about 0.025 wt. % to about 5 wt. % fluorine.

5. The method of claim 1 , wherein:
step (2) is conducted at a purging temperature in a range from about 150° C. to about 400° C.; and
the purging stream consists essentially of nitrogen.

6. The method of claim 1 , wherein:
step (3) is conducted at a peak decoking temperature in a range from about 300° C. to about 500° C.; and
the decoking gas stream in step (3) comprises air or a mixture of nitrogen and oxygen.

7. The method of claim 1 , further comprising a pre-drying step prior to step (1), the pre-drying step comprising contacting the spent catalyst with a pre-drying gas stream consisting essentially of an inert gas.

8. The method of claim 1 , further comprising a re-coking pretreatment step prior to step (1), the re-coking pretreatment step comprising contacting the spent catalyst with a pretreatment stream comprising molecular hydrogen and a hydrocarbon feed comprising C 6 -C 8 alkanes and/or cycloalkanes.

9. The method of claim 1 , further comprising a partial decoking step prior to step (1), the partial decoking step comprising contacting the spent catalyst with a partial decoking gas stream comprising oxygen at a partial decoking temperature in a range from about 150° C. to about 250° C.

10. The method of claim 1 , further comprising a reducing step after step (3), the reducing step comprising contacting the de-coked catalyst with a reducing gas stream comprising molecular hydrogen.

11. The method of claim 10 , wherein the reducing gas stream comprises at least about 25 mole % molecular hydrogen.

12. A reforming process comprising:
(a) contacting a hydrocarbon feed with an aromatization catalyst comprising a transition metal and a catalyst support under reforming conditions in a reactor system to produce an aromatic product;
(b) performing step (a) for a time period sufficient to form a spent aromatization catalyst;
(c) contacting the spent aromatization catalyst with a halogen-containing stream to produce a halogenated spent catalyst, wherein the halogen-containing stream comprises from about 250 to about 5000 ppmv of a chlorine-containing compound and from about 250 to about 5000 ppmv of a fluorine-containing compound;
(d) contacting the halogenated spent catalyst with a purging stream consisting essentially of an inert gas; and
(e) contacting the halogenated spent catalyst with a decoking gas stream comprising oxygen.

13. The process of claim 12 , wherein the reforming process is an in situ process.

14. The process of claim 12 , wherein steps (c)-(e) are performed in a vessel external to the reactor system.

15. A method of treating a spent catalyst comprising a transition metal and a catalyst support, the method comprising:
(1) contacting the spent catalyst with a halogen-containing stream comprising chlorine and fluorine to produce a halogenated spent catalyst;
(2) contacting the halogenated spent catalyst with a purging stream consisting essentially of an inert gas; and
(3) contacting the halogenated spent catalyst with a decoking gas stream comprising oxygen.

16. The method of claim 15 , wherein the spent catalyst comprises:
platinum on a KL-zeolite;
from about 0.1 wt. % to about 10 wt. % platinum;
a support matrix comprising alumina, silica, a mixed oxide thereof, or a mixture thereof;
from about 0.025 wt. % to about 5 wt. % chlorine; and
from about 0.025 wt. % to about 5 wt. % fluorine.

17. The method of claim 16 , further comprising a hydrocarbon treatment step prior to step (3), the hydrocarbon treatment step comprising contacting the halogenated spent catalyst with a hydrocarbon treatment stream comprising a hydrocarbon feed comprising C 6 -C 8 alkanes and/or cycloalkanes.

18. The method of claim 16 , wherein:
the halogen-containing stream comprises Cl 2 , F 2 , and nitrogen, and is substantially free of oxygen-containing compounds; and
a molar ratio of Cl:F in the halogen-containing stream is in a range from about 0.2:1 to about 10:1.

19. The method of claim 16 , wherein:
step (2) is conducted at a purging temperature in a range from about 150° C. to about 400° C.; and
the purging stream consists essentially of nitrogen.

20. The method of claim 16 , wherein:
step (3) is conducted at a peak decoking temperature in a range from about 300° C. to about 500° C.; and
the decoking gas stream in step (3) comprises air or a mixture of nitrogen and oxygen.

Assignees

• Chevron Phillips Chemical Co Lp

Inventors

• Wu An-Hsiang

Classifications

• C10G11/05

  Crystalline alumino-silicates, e.g. molecular sieves · CPC title

• B01J37/18

  with gases containing free hydrogen · CPC title

• B01J38/46

  fluorine-containing · CPC title

• C07C5/325

  of the platinum group · CPC title

• B01J29/7415

  Zeolite Beta · CPC title