Appeal No. 98-3017 2
Application No. 08/437,986
THE INVENTION
The invention is directed to a method of producing a xylene isomer comprising treating a
feed stream containing a mixture of xylene isomers and ethyl benzene with an
isomerization cracking catalyst which converts the ethylbenzene to benzene. Thereafter,
benzene and a specific xylene are sequentially removed. The remaining feed stream is
treated with a second isomerization/cracking catalyst and recycled. Additional features of
the claimed subject matter are set forth in the following illustrative claim.
THE CLAIM
Claim 7 is illustrative of appellants’ invention and is reproduced below.
1. A method for producing at least one xylene isomer product from a feed stream
comprising at least ortho-xylene, meta-xylene, ethylbenzene and para-xylene, the
method comprising the steps of:
starting with a feed stream comprising at least para-xylene, meta-xylene, ortho-
xylene and ethylbenzene;
feeding the feed stream into a pretreatment unit having an isomerization/cracking
catalyst therein in an amount sufficient to cause an approximately 90%
conversion of ethylbenzene to benzene and removing the converted benzene
from the stream;
passing the stream of xylenes to an xylene isomer specific separator;
removing the desired isomer from the stream;
passing the stream through an isomerization unit having an isomerization/cracking
catalyst therein;
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