Appeal No. 1997-1371
Application 08/213,290
Claim 1, the only independent claim, is illustrative of the subject matter on appeal
and reads as follows:
A method of producing bleached wood pulp comprising:
digesting wood chips in a digestion stage to produce brownstock pulp and
weak black liquor;
washing the brownstock pulp and extracting the weak black liquor;
introducing the brownstock pulp, after having been washed, into sequential
bleaching stages, including oxygen delignification and ozone bleaching
stages, to produce a bleached wood pulp product;
the oxygen delignification stage utilizing an oxygen containing stream and
the ozone bleaching stage utilizing an ozone/oxygen containing stream and
producing a waste stream principally containing water vapor, carbon
dioxide, ozone, and oxygen;
recovering the waste stream and scrubbing the waste stream with an
aqueous, sodium sulfide and sodium hydroxide containing solution to
remove ozone and carbon dioxide from the waste stream and thereby form a
scrubbed stream; and
forming the oxygen containing stream for use in the oxygen delignification
stage from the at least part of the scrubbed stream.
The references relied upon by the examiner are:
Barker et al. (Barker) 3,860,479 Jan. 14, 1975
Suzuki et al. (Suzuki) 4,855,123 Aug. 8, 1989
Griggs et al. (Griggs) 5,164,043 Nov. 17, 1992
Friend 5,296,097 Mar. 22, 1994
Prior Art Rejections
A. Claims 1 and 2 stand rejected under 35 U.S.C. § 103, with the examiner relying
2
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