Methods of regenerating aromatization catalysts with a decoking step between chlorine and fluorine addition
Methods for regenerating a spent catalyst are disclosed. Such methods may employ a step of chlorinating the spent catalyst in the gas phase, followed by decoking the chlorinated spent catalyst, and then fluorinating the de-coked catalyst in a fluorine-containing solution of a fluorine-containing compound.
1. A method for regenerating a chlorinated spent catalyst comprising a transition metal and a catalyst support, the method comprising:
(i) contacting the chlorinated spent catalyst with a decoking gas stream comprising oxygen to produce a de-coked chlorinated catalyst,
wherein the chlorinated spent catalyst comprises from about 0.5 wt. % to about 3 wt. % of chlorine; and
(ii) contacting the de-coked chlorinated catalyst with a fluorine-containing solution comprising a fluorine-containing compound in the liquid phase to produce a fluorinated catalyst; wherein:
the transition metal comprises a Group 8-11 transition metal; and
the catalyst support comprises a large pore zeolite having an average pore diameter in a range of from about 7 Å to about 12 Å.
2. The method of claim 1 , wherein the chlorinated spent catalyst further comprises fluorine.
3. The method of claim 1 , wherein the chlorinated spent catalyst comprises at least about 1 wt. % carbon.
4. The method of claim 1 , wherein the de-coked chlorinated catalyst comprises less than about 0.5 wt. % carbon.
5. The method of claim 1 , wherein:
step (i) is conducted at a peak decoking temperature in a range from about 300° C. to about 500° C.;
the decoking gas stream comprises an inert gas and oxygen; and
the decoking gas stream is substantially free of halogen-containing compounds.
6. The method of claim 1 , wherein an amount of the fluorine-containing compound in the fluorine-containing solution provides from about 0.1 to about 10 wt. % of fluorine (F) in the fluorine-containing solution.
7. The method of claim 1 , wherein:
step (ii) is conducted at a fluorination temperature in a range from about 20° C. to about 50° C.; and
the fluorine-containing solution comprises water and at least one of ammonium fluoride and tetramethylammonium fluoride.
8. The method of claim 1 , further comprising a drying step, a calcination step, or both a drying step and a calcination step, after step (ii).
9. The method of claim 1 , wherein:
the transition metal comprises platinum; and
the catalyst support comprises a KL-zeolite and a binder comprising alumina, silica, a mixed oxide thereof, or a mixture thereof.
10. The method of claim 9 , wherein:
the de-coked chlorinated catalyst comprises less than about 0.2 wt. % carbon; and
the fluorinated catalyst comprises from about 0.5 wt. % to about 3 wt. % of fluorine.
11. The method of claim 10 , wherein the fluorinated catalyst comprises from about 0.3 wt. % to about 3 wt. % of platinum.
12. The method of claim 11 , wherein:
the decoking gas stream comprises nitrogen and oxygen; and
the fluorine-containing solution comprises water and at least one of ammonium fluoride and tetramethylammonium fluoride.
13. A method for regenerating a de-coked chlorinated catalyst comprising a transition metal and a catalyst support, the method comprising:
contacting the de-coked chlorinated catalyst with a fluorine-containing solution comprising a fluorine-containing compound in the liquid phase to produce a fluorinated catalyst;
wherein:
the de-coked chlorinated catalyst comprises from about 0.5 wt. % to about 3 wt. % of chlorine;
the de-coked chlorinated catalyst comprises less than about 0.5 wt. % carbon;
the transition metal comprises a Group 8-11 transition metal; and
the catalyst support comprises a large pore zeolite having an average pore diameter in a range of from about 7 Å to about 12 Å.
14. The method of claim 13 , wherein the de-coked chlorinated catalyst further comprises fluorine.
15. The method of claim 14 , wherein the fluorinated catalyst comprises from about 0.5 wt. % to about 3 wt. % of fluorine.
16. The method of claim 13 , wherein the de-coked chlorinated catalyst comprises less than about 0.2 wt. % carbon.
17. The method of claim 13 , wherein an amount of the fluorine-containing compound in the fluorine-containing solution provides from about 0.1 to about 10 wt. % of fluorine (F) in the fluorine-containing solution.
18. The method of claim 13 , wherein:
the de-coked chlorinated catalyst is contacted with the fluorine-containing solution at a fluorination temperature in a range from about 20° C. to about 50° C.; and
the fluorine-containing solution comprises water and at least one of ammonium fluoride and tetramethylammonium fluoride.
19. The method of claim 13 , further comprising a step of drying the fluorinated catalyst, a step of calcining the fluorinated catalyst, or both drying and calcining the fluorinated catalyst.
20. The method of claim 13 , wherein:
the transition metal comprises platinum; and
the catalyst support comprises a KL-zeolite and a binder comprising alumina, silica, a mixed oxide thereof, or a mixture thereof.
21. The method of claim 20 , wherein:
the de-coked chlorinated catalyst comprises less than about 0.2 wt. % carbon;
the de-coked chlorinated catalyst further comprises fluorine;
the fluorinated catalyst comprises from about 0.5 wt. % to about 3 wt. % of fluorine; and
the fluorinated catalyst comprises from about 0.3 wt. % to about 3 wt. % of platinum.