Ex parte Barchas

Board of Patent Appeals and Interferences

Aug 6, 2001

08696578 (B.P.A.I. Aug. 6, 2001)

The opinion in support of the decision being entered today was not
written for publication and is not binding precedent of the Board.

Paper No. 18

UNITED STATES PATENT AND TRADEMARK OFFICE
__________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
__________

Ex parte RICHARD BARCHAS
__________

Appeal No. 1998-2624
Application No. 08/696,578
___________

ON BRIEF
___________

Before KRATZ, DELMENDO and PAWLIKOWSKI, Administrative Patent
Judges.

DELMENDO, Administrative Patent Judge.

DECISION ON APPEAL

This is a decision on an appeal under 35 U.S.C. § 134 from
the examiner’s final rejection of claims 1 through 23, which are
all of the claims pending in the subject application.
The subject matter on appeal relates to a process for the
recovery of olefins from cracked gases. Further details of this
appealed subject matter are recited in illustrative claims 1 and
23 reproduced below:
1. A process for the recovery of olefins from
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Application No. 08/696,578

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cracked gases comprising:

(a) compressing the cracked gas to a pressure
ranging from about 50 to about 250 psig to
produce a compressed cracked gas stream;

(b) washing said compressed gas to remove acidic
gases from said compressed cracked gas stream to
produce a washed compressed cracked gas stream;

(c) selectively hydrogenating acetylenes and
dienes contained in the washed compressed cracked gas
stream to produce a hydrogenated washed compressed gas
stream;

(d) scrubbing said hydrogenated washed compressed
gas stream in an absorber tower with a scrubbing
solution comprising a metallic salt to form a scrubbed
gaseous stream rich in paraffins and hydrogen and a
scrubbed liquid stream rich in olefins and rich
scrubbing solution;

(e) stripping said scrubbed liquid stream in an
olefin stripper to produce a stripped gas stream rich
in olefins and a lean liquid stream;

(f) separating said stripped gas stream rich in
olefins into at least one of an ethylene-rich product
stream, a propylene-rich product stream and a butene-
rich product stream.

23. A process for the recovery of olefins from
cracked gases comprising:

(a) compressing the cracked gas to a pressure
ranging from about 50 to about 250 psig to produce a
compressed cracked gas stream;

(b) washing said compressed cracked gas to remove
acidic gases from said compressed cracked gas stream
to produce a washed compressed cracked gas stream;

(c) selectively hydrogenating acetylenes and
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Application No. 08/696,578

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dienes contained in the washed compressed cracked gas
stream to produce a hydrogenated washed compressed gas
stream;

(d) scrubbing said hydrogenated washed compressed
gas stream in an absorber tower with a scrubbing
solution comprising a metallic salt to form a scrubbed
gaseous stream substantially comprising hydrogen,
methane, ethane, propane and butane; and scrubbed
liquid stream substantially comprising ethylene,
propylene, butylenes and scrubbing solution;

(e) stripping said scrubbed liquid stream in an
olefin stripper to produce a stripped gas stream rich
in olefins and a lean liquid stream; and

(f) separating said stripped gas stream rich in
olefins into at least one of an ethylene-rich product
stream, a propylene-rich product stream and a butene-
rich product stream.

The examiner relies on the following prior art references
as evidence of unpatentability:
Rupp 2,514,294 Jul. 4, 1950
Dunlop et al. 3,401,112 Sep. 10, 1968
(Dunlop)
Montgomery 4,128,595 Dec. 5,
1978
Lendle et al. 4,810,798 Mar. 7, 1989
(Lendle)
Mehra et al. 5,326,929 Jul. 5, 1994
(Mehra)

The following grounds of rejection are presented for our
review in this appeal:
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Application No. 08/696,578

4
I. Claims 1 through 3, 5 through 13, 20, and 23 under 35
U.S.C. § 103(a) as unpatentable over Mehra in view of
Dunlop. (Examiner’s answer, pages 4-6.)
II. Claims 12 and 13 under 35 U.S.C. § 103(a) as
unpatentable over Mehra in view of Dunlop and further
in view of Rupp. (Id. at page 6.)
III. Claim 4 under 35 U.S.C. § 103(a) as unpatentable over
Mehra in view of Dunlop and further in view of
Montgomery. (Id. at page 7.)
IV. Claims 14 through 19, 21, and 22 under 35 U.S.C. §
103(a) as unpatentable over Mehra in view of Dunlop
and further in view of Lendle. (Id.)
We reverse the aforementioned rejections for reasons which
follow.
Under 35 U.S.C. ' 103, the initial burden of establishing a
prima facie case of obviousness rests on the examiner. In re
Piasecki, 745 F.2d 1468, 1471-72, 223 USPQ 785, 787-88 (Fed.
Cir. 1984). In this case, it is our determination that the
examiner has not met the initial burden of proof.

As pointed out by the appellants (appeal brief, page 8),
appealed claim 1 recites the steps of "(d) scrubbing said
hydrogenated washed compressed gas stream in an absorber tower
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Application No. 08/696,578

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with a scrubbing solution comprising a metallic salt to form a
scrubbed gaseous stream rich in paraffins and hydrogen and a
scrubbed liquid stream rich in olefins and rich scrubbing
solution; (e) stripping said scrubbed liquid stream in an olefin
stripper to produce a stripped gas stream rich in olefins and a
lean liquid stream..." Similar language is also recited in
appealed claim 23, the only other independent claim.
The examiner relies on Mehra’s abstract and Mehra’s
discussion of the prior art. (Examiner’s answer, page 5.)
However, the examiner admits that Mehra does not describe the
use of a scrubbing solution comprising a metallic salt as
recited in appealed claims 1 and 23. (Id.) Notwithstanding
this difference, the examiner held as follows:
It would have been obvious to one skilled in the
art to modify the Mehra et al process in view of the
teachings of Dunlop et al to remove the desired
olefins because Dunlop et al disclose that the
solution comprising cuprous nitrate and pyridine is
not expensive if compared with other materials (col.
1, lines 34-47). [Id.]

According to the examiner, "Mehra et al do not limit what kind
of absorbing solvent can be used for their demethanization
absorber (column 3, lines 25-31) although a physical solvent is
preferred (column 7, lines 28-32)." (Id. at page 8.) The
examiner further explains:
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[I]t would have been obvious to one of ordinary skill
in the art to employ the solvent disclosed by Dunlop
to separate paraffins (including methane) from the
gaseous mixture of olefins and paraffins and hydrogen
in the Mehra et al demethanization absorber. This is
because (1) the Dunlop et al absorbent solution is not
expensive (2) it can separate paraffins (including
methane) from the mixture of olefins and paraffins and
especially, (3) since the Dunlop et al absorbent
solution can separate olefins from paraffins including
methane, the additional conventional downstream
separation steps *** required/needed in the Mehra et
al process such as separating ethylene (an olefin)
from ethane (a paraffin) and separating propylene
(olefin) from propane (a paraffin) can be eliminated
or reduced to a smaller scale. [Id. at p. 9.]

Initially, we note that the examiner has combined Mehra’s
discussion of the prior art with Mehra’s disclosure of the
hydrogen and ethylene recovery process. However, the basis for
mixing the two disclosures as if they related to exactly the
same process is not entirely clear to us. Nevertheless, we are
in substantial agreement with the appellant’s arguments that the
examiner’s basic position is not well founded. (Appeal brief,
pages 7 through 14; reply brief, pages 1-7.)
Mehra’s abstract describes a process for contacting an
olefins-containing feed gas stream, which has been freed of CO2
and sulfur compounds, compressed, cooled, and dried, with a
solvent in an intercooled and reboiled demethanizing absorber to
produce a rich solvent bottom stream containing ethylene and
heavier hydrocarbons and an absorber overhead stream. According
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Application No. 08/696,578

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to Mehra, the absorber overhead stream is fed to a methane
absorber which recovers a hydrogen product stream as overhead
and produces a rich solvent stream as bottoms. Mehra’s abstract
further teaches:
When recovering up to 50% of the incoming
hydrogen, this rich solvent stream from the methane
absorber is fed to the demethanizing absorber, but
when recovering from 20% to 100% of the incoming
hydrogen, this rich solvent stream is recycled in part
to the demethanizing absorber and in part is fed to a
methane stripper which sends its bottoms to the
methane absorber and its overhead to an auto
refrigerated recovery unit which removes H2, CH4, and
CO as a fuel gas product and produces an ethylene and
heavier stream. The rich solvent stream from the
demethanizing absorber is separated in a solvent
regenerator into an overhead stream of ethylene and
heavier hydrocarbons and a bottom lean solvent stream
for recycle to the methane absorber and then to the
demethanizing absorber. The bottom stream of the
recovery unit and the overhead stream of the solvent
regenerator are combined to form an ethylene and
heavier product stream.

By contrast, Dunlop’s teachings are directed to an entirely
different purpose. Specifically, Dunlop teaches various
separation processes including the recovery of monoolefins from
paraffins using various metal salts. (Column 1, lines 20-47.)
From our perspective, neither Mehra nor Dunlop provides any
evidence that one of ordinary skill in the art would have
considered the separation process described in Dunlop to be
interchangeable with, much less desirable over, the
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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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In the appellant’s claimed process, however, the feed into
the absorber tower is not a "C3-and-lighter fraction." Instead,
the feed is a "hydrogenated washed compressed gas stream"
produced from steps (a) through (c) of appealed claim 1 or 23.
The examiner’s rejection does not account for this difference.
The remaining references have been applied only for the
purpose of addressing the additional features recited in the
dependent claims. However, they do not remedy the fundamental
deficiencies in the examiner’s combination of Mehra and Dunlop.
Because the examiner has not pointed to a specific
teaching, motivation, or suggestion in the prior art to combine
the references so as to arrive at the here claimed invention, we
hold that the examiner has engaged in impermissible hindsight
reconstruction using the appellant’s own specification as a
template. In re Fritch, 972 F.2d 1260, 1266, 23 USPQ2d 1780,
1784 (Fed. Cir. 1992); Interconnect Planning Corp. v. Feil, 774
F.2d 1132, 1138, 227 USPQ 543, 547 (Fed. Cir. 1985); W. L. Gore
& Assoc. v. Garlock, Inc., 721 F.2d 1540, 1553, 220 USPQ 303,
312-13 (Fed. Cir. 1983).
In summary, the examiner’s rejections of (i) claims 1
through 3, 5 through 13, 20, and 23 under 35 U.S.C. § 103(a) as
unpatentable over Mehra in view of Dunlop, (ii) claims 12 and 13
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Application No. 08/696,578

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under 35 U.S.C. § 103(a) as unpatentable over Mehra in view of
Dunlop and further in view of Rupp, (iii) claim 4 under 35
U.S.C. § 103(a) as unpatentable over Mehra in view of Dunlop and
further in view of Montgomery, and (iv) claims 14 through 19,
21, and 22 under 35 U.S.C. § 103(a) as unpatentable over Mehra
in view of Dunlop and further in view of Lendle are reversed.

The decision of the examiner is reversed.
REVERSED

PETER F. KRATZ )
Administrative Patent Judge )
)
)
)
) BOARD OF PATENT
ROMULO H. DELMENDO )
Administrative Patent Judge ) APPEALS AND
)
) INTERFERENCES
)
)
BEVERLY A. PAWLIKOWSKI )
Administrative Patent Judge )

Appeal No. 1998-2624
Application No. 08/696,578

11

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