Appeal No. 2003-0172
Application 09/810,801
at the expense of the Wernicke ‘520 hydrotreating step, the
yields of ethylene and propylene are increased by, respectively,
about 7 wt% and about 3 wt%.
The feedstock in the examples in the appellants’
specification is different than that in the Wernicke ‘520
examples. The appellants’ feedstock is an Alaskan crude oil
having a hydrogen content of 13.2 wt% and a boiling range mostly
in the below 200ºC to 540ºC range, whereas the feedstock in the
Wernicke ‘520 examples is a gas oil having a hydrogen content of
13.13 wt% and a boiling range of 208ºC to 354ºC. Even though
there is this difference in feedstocks, a comparison of the
yields obtained by the appellants and Wernicke ‘520 is
informative. The appellants’ ranges of yields of ethylene and
propylene are, respectively, 19.3-20.4 wt% and 12.1-12.2 wt%.
These yields, obtained without a hydrotreating step, are
comparable to the yields in the Wernicke ‘520 comparative
example 1 which were obtained without a hydrotreating step, i.e.,
21.0 wt% and 12.2 wt%. Thus, it reasonably appears that the
appellants have merely eliminated the hydrotreating step along
with its function of increasing olefin yield. As indicated
above, doing so would have been prima facie obvious to one of
ordinary skill in the art. The appellants have not shown that,
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