Appeal No. 97-3640
Application No. 08/406,272
Strack describes a process for separating propylene from a mixture of cracked hydrocarbons
produced by a cracking unit. A feed 10 of alkanes, naphtha or gas oil, or combinations thereof is
introduced into a cracking furnace 12. The cracked gases 11 leaving the furnace 12 are quenched 14
and compressed 17. The compressed gases are fed into an acid gas removal vessel 16 where they
undergo acid gas removal, typically with the addition of a base such as NaOH 18. The gases are dried
in dehydration system 13 and thereafter separated into various fractions. (abstract; col. 4, lines 15-43).
The examiner relies on Strack "[t]o the extent the Skraba reference is construed as not
describing sodium hydroxide in its description of the 'caustic' zone" (Ans. page 4, paragraph 4). The
examiner also relies on Strack to show that effluent steam-cracked gases in line 19 have water in them
when they contact the caustic washer/acid gas removal vessel based upon subsequent drying in
dehydration system 13 (Ans. paragraph bridging pages 4-5). Finally, the examiner states the relative
amounts of sodium hydroxide (oxygen-containing metal compound) to CO (claims 9-11); and, the
2
specific reaction conditions of temperature (claims 16-17) and pressure (claims 18-19) are well known,
art-recognized, result-effective variables and concludes it would have been obvious to one of ordinary
skill in the art to optimize these variables (Ans. page 5, paragraph three).
Appellant argues neither Skraba nor Strack teaches a positive step of "adding" water to an
olefin-containing fluid and thereafter contacting the water-containing fluid with a composition such as
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Last modified: November 3, 2007