Appeal No. 1998-2624
Application No. 08/696,578
demethanization step described in Mehra. In re Dembiczak, 175
F.3d 994, 999, 50 USPQ2d 1614, 1617 (Fed. Cir. 1999) ("[T]he
best defense against the subtle but powerful attraction of a
hindsight-based obviousness analysis is rigorous application of
the requirement for a showing of the teaching or motivation to
combine prior art references.").
Nor is there any evidence in the applied prior art to
establish that one of ordinary skill in the art would have made
such a substitution with a reasonable expectation of success,
consistent with the objectives stated in Mehra. In re Vaeck,
947 F.2d 488, 493, 20 USPQ2d 1438, 1442 (Fed. Cir. 1991) (citing
In re Dow Chemical Co., 837 F.2d 469, 473, 5 USPQ2d 1529, 1531
(Fed. Cir. 1988).
Regarding Mehra’s discussion of the prior art (column 2,
line 26 to column 3, line 7), we note the following:
A low-pressure debutanizing stripper is located
in the compression train to remove C5 and heavier
fractions from the cracked gas. . .
The C3-and-lighter fraction is fed to the
absorber column. The C2’s and C3’s are absorbed by
the solvent while methane and lighter components,
together with some ethylene, leave the top of the
absorber. This overhead stream is fed to a small
tail-end demethanizer where essentially all the C2’s
are recovered. [Col. 2, ll. 31-34, 58-63.]
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