Appeal No. 2003-0172
Application 09/810,801
boiling feedstock must be hydrotreated before being thermally
cracked. In fact, in comparative example 1, Wernicke ‘520
thermally cracks this feedstock without any preceding
hydrotreatment.
The appellants argue that the feedstock used in all of the
Wernicke ‘520 examples, including comparative example 1, contains
13.13 wt% hydrogen, which is within the range recited in the
appellants’ claim 1, yet Wernicke ‘520 hydrotreats this feedstock
in the examples of his invention and shows that this
hydrotreatment increases the olefin yield relative to that
obtained in comparative example 1 (brief, page 5). Hence, the
appellants’ argue, Wernicke ‘520 teaches away from eliminating
the hydrotreating step (brief, pages 5-6).
It would have been prima facie obvious to one of ordinary
skill in the art to eliminate the hydrotreating step along with
its disclosed function of increasing the olefin yield, in order
to reduce the cost of the process. See In re Thompson, 545 F.2d
1290, 1294, 192 USPQ 275, 277 (CCPA 1976).
In the Wernicke ‘520 examples the ranges of the ethylene and
propylene yields are, respectively, 26.2-30.0 wt% and 14.3-
16.1 wt%, whereas in comparative example 1 the ethylene and
propylene yields are, respectively, 21.0 wt% and 12.2 wt%. Thus,
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