Aromatics isomerization using a dual-catalyst system
AssigneeUop LLC
InventorsSanjay B. Sharma, Aaron J. Imrie
Life of this patent
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Abstract
This invention is drawn to a catalyst system comprising two or more molecular sieves, including at least one non-zeolitlc molecular sieve and one zeolitic aluminosilicate, having specified contrasting pore structures and to a process for isomerizing a non-equilibrium mixture of xylenes and ethylbenzene using the subject catalyst system to obtain an improved yield of para-xylene from the mixture relative to prior-art processes.
Claims6
A process for the isomerization of a non-equilibrium feed mixture of 10 xylenes and ethylbenzene comprising contacting the feed mixture with a catalyst system comprising a physical mixture of a first catalyst comprising from about 0.1 to 2 mass-% of at least one platinum-group metal component, about 10 to 90 mass-% of at least one non-zeolitic molecular sieve, and an inorganic-oxide binder;
- and a second catalyst comprising from 0.02 to 0.08 mass-% of at least one platinum-group metal component, from about 10 to 99 mass-% of at least one zeolitic aluminosilicate, and an inorganic-oxide, wherein the content of platinum-group metal is no more than about 30% of the content of platinum-group metal in the first catalyst, at isomerization conditions comprising a temperature of from about 300° to 600° C., a pressure of from about 100 kPa to 5 MPa and a liquid hourly space velocity of from about 0.5 to 50 hr−1 with respect to the combined catalyst system to obtain an isomerized product comprising a higher proportion of at least one xylene isomer than in the feed mixture.
A process for the isomerization of a non-equilibrium feed mixture of xylenes and ethylbenzene comprising the steps of:
- (a) contacting the feed mixture with a first catalyst comprising from about 0.1 to 2 mass-% of at least one platinum-group metal component, about 10 to 90 mass-% of at least one non-zeolitic molecular sieve, and an inorganic-oxide binder;
- at first isomerization conditions comprising a temperature of from about 100° to 600° C., a pressure of from about 100 kPa to 5 MPa and a liquid hourly space velocity of from about 1 to 100 hr−1, to obtain an isomerized intermediate;
- and,
- (b) contacting the isomerized intermediate with a second catalyst comprising from 0.02 to 0.08 mass-% of at least one platinum-group metal component, from about 10 to 99 mass-% of at least one zeolitic aluminosilicate, and an inorganic-oxide binder, wherein the content of platinum-group metal is no more than about 30% of the content of platinum-group metal in the first catalyst, at second isomerization conditions comprising a temperature of from about 100° to 600° C., a pressure of from about 100 kPa to 5 MPa and a liquid hourly space velocity of from about 1 to 100 hr−1, to obtain an isomerized product comprising a higher proportion of at least one xylene isomer than in the feed mixture.
Dependencies are inferred from the claim text.