Appeal 2007-3383
Application 10/452,939
removing sulphur from a gas in order to prevent deactivation of the catalyst
by the aromatic hydrocarbons (i.e., benzene, toluene and xylenes) and
because use of such multiple stages are known in the Claus process as
disclosed by both Michel and Tellier.
Moreover, contrary to Appellants’ arguments, Tellier’s first
embodiment indicates that the “Claus reactors” (i.e., more than one reactor
in the series of reactors) are modified to have a first, protecting deoxidation
catalyst followed by traditional Claus catalyst (i.e., the series of reactors
would have the F-A-F-A catalyst arrangement) (Tellier, col. 2, ll. 12-22).
Tellier’s claim to “at least one catalytic reaction zone having a deoxidation
catalyst and the Claus oxide catalyst” further indicates that Tellier discloses
multiple reactors in series having the deoxidation catalyst and the traditional
Claus catalyst in each reactor of the series (i.e., the F-A-F-A catalyst
arrangement) (Tellier, claim 1).
Regarding claim 38, the additional recitation that the “feed contains
200 ppm or less O2” is suggested by Tellier. Tellier discloses that the
oxygen in the feed may be “up to 5000 vpm” (i.e., zero to 5000 vpm)
(Tellier col. 2, ll. 24-26). Moreover, Tellier’s disclosure that oxygen is
detrimental to the catalysts provides further suggestion to decrease the
concentration of oxygen in the feed. Thus, Appellants’ argument that the
lowest amount Tellier discloses is 800 vpm in Example 8 is not persuasive.
We add that for independent claims 1 and 38, the Examiner relies on
Tellier’s disclosure to use a series of reactors as providing motivation for
using a series of the reactors containing both deoxidation catalyst and
traditional Claus catalyst (Answer 7). Michel, while bolstering the
Examiner’s position that it is known to use multiple catalytic stages in the
8
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