Appeal No. 1996-3493
Application No. 08/451,697
a catalyst to be considered attrition resistant, the attrition ratio (AR) should be less than or equal to2
about 3" (specification, page 15, lines 12-14). Thus, in this case, the words “attrition resistant,” as
specifically defined in the specification, are essential to point out the invention defined by the claims, i.e.,
they breathe life and meaning to the claims. Therefore, in this case, the preamble does limit the scope
of the claims to a defined “attrition resistant” catalyst composition. Thus, it follows that the examiner
has failed to address all of the claim limitations. In short, the examiner has not pointed out and we do
not find where Bergna, Abrams or Beck disclose or suggest catalysts having an attrition ratio less than
or equal to 3, i.e., “attrition resistant” as explicitly defined in the specification.
Secondly, viewing the invention as a whole, we find that neither Bergna, Abrams nor Beck
provide sufficient guidance or direction to enable one of ordinary skill in the art to select the particular
combination of rho and/or chabazite acidic zeolites with only certain specific particulate binders to
provide a catalyst composition having an attrition ratio less than or equal to 3 as defined in the
2 As set forth in the paragraph bridging pages 14-15 of the specification,
Attrition measurements are performed using an attrition mill which simulates particle
attrition near the gas spargers of a fluidized bed. A catalyst charge is loaded into a column fitted
with a single 0.016" perforation. Air flows through the perforation, fluidizes the catalyst bed, and
causes attrition. For most measurements, the constant air flow through the mill is calibrated to
yield a linear velocity of 760 ft/s through the orifice; this compares to a typical velocity of 150 ft/s
in a commercial fuel spargers. The attrition mill measurement accelerates attrition by a factor of
roughly thirty. A 24 hour attrition measurement is a reliable indicator of attrition in a commercial
reactor. Attrited fines (i.e., those particles lower than 20 micrometers in diameter) are collected in
an overhead flask which is fitted with a porous thimble. Flask weight, recorded as a function of
time, is used to calculate attrition. The determination of attrition is calculated as an attrition ratio,
AR: catalyst attrition divided by the attrition rate of a fluid cracking catalyst standard (FCC). The
FCC standard is supplied by Davison Chemical, Baltimore Maryland (SMR-5-5209-0293).
- 7 -
Page: Previous 1 2 3 4 5 6 7 8 9 Next
Last modified: November 3, 2007