Ex parte Steffens

Board of Patent Appeals and Interferences

Mar 15, 2000

08213347 (B.P.A.I. Mar. 15, 2000)

Application for patent filed March 15, 1994.1
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(2) is not binding precedent of the Board.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. 14
UNITED STATES PATENT AND TRADEMARK OFFICE
_____________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
_____________
Ex parte TODD R. STEFFENS
_____________
Appeal No. 1996-3491
Application 08/213,3471
______________
ON BRIEF
_______________
Before JOHN D. SMITH, HANLON and KRATZ, Administrative Patent
Judges.
JOHN D. SMITH, Administrative Patent Judge.
DECISION ON APPEAL
This is an appeal pursuant to 35 U.S.C. § 134 from the
final rejection of claims 1-15, the only claims in the
application.
Appeal No. 1996-3491
Application 08/213,347
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Representative claims 1 and 9 are reproduced below:
1. A process for controlling afterburning in a
fluid catalytic cracking regenerator, comprising:
providing a catalyst bed in the fluid catalytic
cracking regenerator;
providing a regenerator vapor region above the
catalyst bed;
injecting a first and second stream of air into
the catalyst bed, wherein the first and second streams
of air are spaced apart from one another;
taking a temperature measurement in the catalyst
bed;
taking a temperature measurement in the
regenerator vapor region;

calculating the difference between the
temperature of the catalyst bed and the temperature of the
vapor region of the fluid catalytic cracking regenerator as
)T; and
increasing oxygen concentration in one of the
first and second streams of air, when )T has an absolute
value that is greater than a predetermined value, until
the absolute value of )T is less than or equal to
the predetermined value.
9. A process for controlling afterburning in a
fluid catalytic cracking regenerator, comprising:
providing a catalyst bed in the fluid catalytic
cracking regenerator;
providing a regenerator vapor region above the
catalyst bed;
injecting a first and second stream of air into
Appeal No. 1996-3491
Application 08/213,347
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the catalyst bed, wherein the first and second combustion
streams are spaced apart from one another;

Appeal No. 1996-3491
Application 08/213,347
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taking a temperature measurement in at least two
separate locations within the regenerator vapor region;
calculating the difference between the
temperature measurement of each location within the
regenerator vapor region as )T; and
increasing oxygen concentration in one of the
first and second streams of air, when )T has an absolute
value that is greater than a predetermined value, until
the absolute value of )T is less than or equal to the
predetermined value.
Prior art references relied upon by the examiner as
evidence
of obviousness are:
Pohlenz 3,206,393 Sep.
14, 1965
Luckenbach 4,243,517 Jan.
6, 1981
Cabrera et al. (Cabrera) 4,849,091
Jul. 18, 1989
Appealed claims 1-15 stand rejected under 35 U.S.C. §
112, second paragraph, as being indefinite for failing to
particularly point out and distinctly claim the subject matter
which applicant regards as the invention. Appealed claims 1-8
stand rejected under 35 U.S.C. § 103 as being unpatentable
over the combination of Pohlenz and Luckenbach. Appealed
claims 9-15 stand rejected under 35 U.S.C. § 103 as being
unpatentable over the combination of Cabrera and Luckenbach.
Appeal No. 1996-3491
Application 08/213,347
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BACKGROUND
The subject matter of the claims on appeal is directed to
a process for controlling afterburning in a fluid catalytic
cracking generator. Fluid catalytic cracking is a hydrocarbon
cracking process in which vaporized hydrocarbon feed is
cracked in the presence of microsperoidal catalyst particles
(specification, page 1, lines 22-24). During the cracking
process, carbonaceous material deposits on the surface of the
catalyst and essentially coats it (specification, page 2, line
1) to produce a catalyst which is referred to as “coked”
(specification, page 2, lines 1 and 2). Eventually, the
accumulation of carbonaceous material deactivates the catalyst
to the point that it becomes ineffective in enhancing the
equilibrium balance of the cracking reaction under standard
cracking conditions (specification, page 2, lines 4-10), and
such a deactivated catalyst is then referred to as a “spent”
catalyst which requires regeneration. For this purpose, the
catalyst is transferred to a regeneration section of a fluid
catalytic cracking unit wherein the coated coke on the
catalyst is combusted by injection of air into a bed of the
spent catalyst in the regenerator section. However,
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Application 08/213,347
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unrecovered volatile hydrocarbons typically pass with the
spent catalyst into the regeneration section wherein they are
combusted in preference to the coke on the spent catalyst, and
this results in the exhaustion of the oxygen in the air in
localized areas, e.g., where the spent catalyst and volatile
hydrocarbons enter the regeneration section. Because such
localized areas in the dense phase catalyst bed are
essentially starved of oxygen, carbon monoxide, rather than
carbon dioxide, is formed by the combustion of the coke in the
dense bed. The carbon monoxide thus formed in these localized
areas passes from the dense catalyst bed into a dilute
catalyst phase (regenerator vapor region) where it may react
with oxygen in that region to cause “afterburning” with the
concomitant generation of heat and substantial increase in
temperature in the regenerator vapor region to such an extent
that the catalyst is again deactivated. See Luckenbach at
column 2, lines 2-59. Accordingly, “afterburning” produces
undesirable regions of excess heat in regions of low catalyst
density zones and detrimentally affects the regeneration of
the catalyst and risks mechanical damage of the regenerator
vessel (specification, page 2, lines 21-24).
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Application 08/213,347
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Appellants address the
afterburning problem by strategically increasing the
concentration of oxygen present in the regenerator in areas in
which the oxygen is starved and carbon monoxide is
preferentially produced. Specifically, appellants increase
the presence of oxygen in the regenerator by directly
injecting oxygen into one of two air streams and thus increase
the oxygen concentration in an air stream that is injected
into the catalyst bed. Significantly, this increase in oxygen
concentration is effected in appellants’ process in response
to a temperature differential that results from the excess
heat produced by the “afterburning” combustion. Accordingly,
appellants’ claimed process recites the critical step of
“increasing oxygen concentration in one of the first and
second streams of air, when the )T has an absolute value that
is greater than a predetermined value, until the absolute
value of )T is less than or equal to the predetermined value
(appealed claim 1, emphasis added).”
THE REJECTION UNDER 35 U.S.C. § 112, SECOND PARAGRAPH
The examiner rejected claims 1-15 under 35 U.S.C. § 112,
second paragraph, as being indefinite for failing to
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Application 08/213,347
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particularly point out and distinctly claim the subject matter
which applicant regards as the invention. The examiner bases
this rejection on the appellants’ use of the phrase
“predetermined value” in independent claims 1 and 9
(examiner’s answer, pages 3-4). Specifically, the examiner
argues that the phrase refers to no precise value which would
permit a person of ordinary skill in the art to fully
understand the metes and bounds of the invention (examiner’s
answer, page 9).
Appeal No. 1996-3491
Application 08/213,347
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We will not sustain this rejection. The “definiteness of
the language employed must be analyzed-not in a vacuum, but
always in light of the teachings of the prior art and of the
particular application disclosure as it would be interpreted
by one possessing the ordinary level of skill in the pertinent
art.” In re Moore, 439 F.2d 1232, 1235, 169 USPQ 236, 238
(CCPA 1971). Appellants have provided ample guidance on pages
8-13 of their specification for determining the “predetermined
value” for the temperature differential )T. We particularly
note that on page 13, lines 10-12, appellants provide the
precise values sought by the examiner. This is sufficient
guidance to one possessing the ordinary level of skill in this
art to determine the metes and bounds of the questioned claim
language.
THE REJECTIONS UNDER 35 U.S.C. § 103
The examiner has rejected appealed claims 1-8 under
35 U.S.C. § 103 as being unpatentable over the combination of
Pohlenz and Luckenbach and appealed claims 9-15 under 35
U.S.C.
§ 103 as being unpatentable over the combination of Cabrera
and Luckenbach.
Appeal No. 1996-3491
Application 08/213,347
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We will not sustain either of these rejections.
Appellants essentially concede that prior art workers have
utilized temperature differentials as an indication of the
occurrence of afterburning and that the value of a temperature
differential ()T) has been controlled by increasing or
decreasing the total amount of oxygen or air input to a dense
catalyst bed in a regenerator section. See the specification
at page
4. Appellants’ characterize the prior art use of a
temperature differential control as involving the regulation
of the rate of injection of air to increase the oxygen
concentration in a regeneration zone (appeal brief, pages 9
and 10). On the other hand, the invention as claimed uses a
temperature differential to increase the concentration of
oxygen in a stream of air that is fed into the regeneration
zone. See Figure 1 of the application wherein system
controller 122 controls flow valves 123 and 124 of oxygen
supply line 125 for increasing the oxygen concentration in air
streams 115 and 113 prior to the introduction of the air into
the regenerator section. As argued by appellants and
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Application 08/213,347
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acknowledged by the examiner, the prior art does not disclose
this feature of the claimed invention, i.e., a step in which
the oxygen concentration is increased in one of the first or
second streams of air. At best, the “secondary reference” to
Luckenbach teaches that one can use as oxygen-containing
regeneration gas either air or oxygen-enriched air (col. 4,
lines 62-64). Such a teaching is not equivalent to increasing
the oxygen concentration of an air stream in response to a
temperature differential.
The examiner argues that a person of ordinary skill in
the art would recognize that the amount of oxygen can be
controlled by “one of two equivalent methods” (examiner’s
answer, page 10). The equivalent methods contemplated by the
examiner are (1) controlling the rate of introduction of air
while maintaining its concentration of oxygen constant and (2)
controlling the concentration of oxygen in the air while
maintaining the rate of air delivery constant. The examiner
has cited no prior art, however, which discloses the control
of an oxygen concentration in an air stream in response to any
process parameter, much less for the purpose recited in the
claimed process. Thus in the record before us, there is no
Appeal No. 1996-3491
Application 08/213,347
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objective evidence of the method (2) itself, much less of its
alleged equivalency with method (1). Absent such evidentiary
support, the examiner has not established a prima facie case
of obviousness for the herein claimed process. Because there
is an inadequate factual basis to support a legal conclusion
of obviousness, the examiner’s rejections cannot be sustained.
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Application 08/213,347
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The decision of the examiner is reversed.
REVERSED
)
JOHN D. SMITH )
Administrative Patent Judge )
)
)
) BOARD OF PATENT
ADRIENE LEPIANE HANLON )
Administrative Patent Judge ) APPEALS AND
)
) INTERFERENCES
)
PETER F. KRATZ )
Administrative Patent Judge )
JDS:hh
Appeal No. 1996-3491
Application 08/213,347
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EXXON RESEARCH AND ENGINEERING COMPANY
P.O. BOX 390
FLORHAM PARK, NJ 07932