Ex parte LU et al.

Board of Patent Appeals and Interferences

Aug 23, 1999

08240800 (B.P.A.I. Aug. 23, 1999)

Application for patent filed May 10, 1994. According1
to appellants, this application is a continuation of
Application No. 08/059,243, filed May 7, 1993, now abandoned.
-1-
THIS OPINION WAS NOT WRITTEN FOR PUBLICATION
The opinion in support of the decision being entered
today (1) was not written for publication in a law
journal and (2) is not binding precedent of the Board.
Paper No. 23
UNITED STATES PATENT AND TRADEMARK OFFICE
________________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
________________
Ex parte WEI-KAO LU, CHARLES Q. JIA,
VISHWAPRAKASH S. HEGDE and STEVEN HOI-CHIU NG
________________
Appeal No. 96-1188
Application No. 08/240,8001
________________
ON BRIEF
________________
Before KIMLIN, JOHN D. SMITH and OWENS, Administrative Patent
Judges.
KIMLIN, Administrative Patent Judge.
DECISION ON APPEAL
Appeal No. 96-1188
Application No. 08/240,800
-2-
This is an appeal from the final rejection of claims 23-
44, all the claims remaining in the present application.
Claim 23 is illustrative:
23. A process for desulfurizing sulfur dioxide-
containing gas comprising the steps of:
a) absorbing sulfur dioxide gas into an aqueous
sulfide solution to remove said sulfur dioxide
from a stream of gas, said aqueous sulfide
solution being contained in a reactor,
b) absorbing additional sulfur dioxide gas into said
reactor to form hydrogen sulfide gas,
c) removing hydrogen sulfide gas from said reactor,
d) absorbing additional sulfur dioxide gas in said
reactor, after said removal of hydrogen sulfide
gas, to form bisulfite in said reactor, and
e) removing aqueous bisulfite-containing solution
from said reactor, with said hydrogen sulfide and
bisulfite being the principal products of steps
b) and d).
The examiner relies upon the following references as
evidence of obviousness:
Strong et al. (Strong) 3,784,630 Jan. 8, 1974
Miller 4,837,001 Jun. 6, 1989
Talonen et al. (Talonen) 4,937,057 Jun. 26, 1990
Brannland et al. (Canada '378) 948,378 Jun. 4, 1974
(Canadian patent)
Appellants' claimed invention is directed to a process
for desulfurizing sulfur dioxide-containing gas which entails
Appeal No. 96-1188
Application No. 08/240,800
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passing the gas into an aqueous sulfide solution which
ultimately forms hydrogen sulfide gas, removing the hydrogen
sulfide from the reactor, absorbing additional sulfur dioxide
gas in the solution to form bisulfite, and removing the
bisulfite-containing solution from the reactor.
Appealed claims 23-31 and 33-44 stand rejected under
35 U.S.C. § 103 as being unpatentable over Canada '378 in view
of Talonen and Strong. In addition, claims 23-44 stand
rejected under 35 U.S.C. § 103 as being unpatentable over
Canada '378 in view of Talonen and Strong in further view of
Miller.
Upon careful consideration of the opposing arguments
presented on appeal, we concur with appellants that the prior
art relied upon by the examiner fails to establish a prima
facie case of obviousness for the claimed subject matter.
Accordingly, we will not sustain the examiner's rejections.
In our view, the examiner has not established that the
collective teachings of Canada '378, Talonen, Strong and
Miller teach or suggest the manipulative steps of the claimed
process, namely, (1) forming hydrogen sulfide gas by absorbing
sulfur dioxide into an aqueous sulfide solution, (2) removing
Appeal No. 96-1188
Application No. 08/240,800
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hydrogen sulfide from the reactor, (3) forming bisulfite in
the solution by absorbing additional sulfur dioxide after
removal of the hydrogen sulfide gas, and (4) removing the
aqueous bisulfite-containing solution from the reactor.
Although Talonen discloses at column 4 that bisulfite and
hydrogen sulfide are products of some of the reactions that
occur during the introduction of sulfur dioxide into a sulfide
solution, neither Talonen nor any of the other cited
references provides a teaching of the sequence of steps
defined by the process presently on appeal. Canada '378
discloses a process for inhibiting the emission of hydrogen
sulfide during the absorption of sulfur dioxide in a sulfide
solution and fails to teach the generation of bisulfite.
Talonen, in the paragraph bridging columns 4 and 5, teaches
that bisulfite is first produced when sulphur dioxide is
introduced into a sulphide solution and, then, after a certain
amount of sulphur dioxide is absorbed by the sodium sulphide,
plenty of hydrogen sulphide is released from the solution.
Also, Talonen does not disclose removing bisulfite as a
product but, rather, elemental sulfur is the product of the
Talonen process.
Appeal No. 96-1188
Application No. 08/240,800
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Strong does not alleviate the deficiencies of Canada '378
and Talonen. Strong discloses the absorption of sulfur
dioxide gas in an aqueous sulfide solution to form a
precipitate that is predominantly metal sulfite and elemental
sulfur. Strong does not disclose the production of hydrogen
sulfide and, although the reference teaches that it is
possible to form some metal bisulfite, it is disclosed that
"the bisulfite forms only when the pH of the solution is
relatively low, and at such pH, there is an insufficient
absorption of sulfur dioxide in the slurry, and excessive
sulfur dioxide may pass through the slurry to atmosphere"
(column 4, lines 3-7). Since the primary goal of Strong is to
obtain the maximum removal of sulfur dioxide (column 4, lines
7 et seq.), it is clear that Strong provides a teaching away
from the claimed process of forming bisulfite in the reactor.
The examiner states at page 3 of the Answer that "[i]t
would have been obvious to one having ordinary skill in the
art at the time the invention was made to have modified the
scrubbing system of '378 as suggested by Talonen and Strong
because doing so assures complete removal of SO ." However,x
the examiner has failed to sufficiently explain how the
Appeal No. 96-1188
Application No. 08/240,800
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process of Canada '378 would be modified in accordance with
the teachings of Talonen and Strong such that appellants'
claimed process would result. It appears to us that the
examiner has found that various sulfur dioxide scrubbing
processes in the prior art which utilize aqueous sulfide
solutions generate hydrogen sulfide gas and bisulfite and,
therefore, concludes that one of ordinary skill in the art
would be able to somehow modify all the prior art processes to
arrive at the claimed process. However, it is well settled
that the prior art must provide some teaching or suggestion of
the claimed process or some motivation why one of ordinary
skill in the art would perform the claimed steps. Inasmuch as
the examiner has not established on this record the requisite
teaching, suggestion or motivation, we must conclude that the
examiner has not established a prima facie case of obviousness
for the claimed subject matter.
In conclusion, based on the foregoing, we are constrained
to reverse the examiner's rejections.
REVERSED
EDWARD C. KIMLIN )
Appeal No. 96-1188
Application No. 08/240,800
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Administrative Patent Judge )
)
)
)
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JOHN D. SMITH ) BOARD OF PATENT
Administrative Patent Judge ) APPEALS AND
) INTERFERENCES
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TERRY J. OWENS )
Administrative Patent Judge )
ECK:clm
Appeal No. 96-1188
Application No. 08/240,800
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Edward A. Steen, Patent Counsel
Inco Patents & Licensing
Park 80 West
Plaza Two
Saddle Brook, NJ 07662