Ex Parte Rumpf et al

Board of Patent Appeals and Interferences

Mar 28, 2008

09857490 (B.P.A.I. Mar. 28, 2008)

UNITED STATES PATENT AND TRADEMARK OFFICE
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BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
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Ex parte FEDERICK H. RUMPF,
ROSCOE W. TAYLOR, and
ALVIN E. TOOMBS

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Appeal 2008-0984
Application 09/857,490
Technology Center 1700
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Decided: March 28, 2008
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Before CHUNG K. PAK, CATHERINE Q. TIMM, and
JEFFREY T. SMITH, Administrative Patent Judges.

SMITH, Administrative Patent Judge.

DECISION ON APPEAL
Statement of the Case
This is an appeal under 35 U.S.C. § 134 from a final rejection of
claims 2-8 and 15-17. The rejection of claim 18 has been withdrawn. (Ans.
3). We have jurisdiction under 35 U.S.C. § 6.
Appeal 2008-0984
Application 09/857,490

Appellants’ invention relates to a process for the manufacture of
carbon black that employs dewatered, heated off-gas in a fuel rich
combustion strategy. An understanding of Appellants’ invention can be
gleaned from independent claim 15 which appears below:
15. A furnace carbon black producing process comprising the
steps of:
(a) obtaining off-gas from a carbon black furnace,
(b) dewatering and heating the off-gas and substantially
removing any existing carbon black therefrom to obtain
dewatered and heated off-gas, and then
(c) feeding a combustion gas feed stream comprising the
dewatered and heated off-gas and feeding an oxidant gas stream
comprising an oxidant gas to a burner portion of the carbon
black furnace, wherein the carbon black furnace comprises said
burner portion wherein said combustion gas feed stream is
combusted in the presence of said oxidant gas feed stream to
produce hot combustion gases and a reactor portion wherein
carbon black is produced by an interaction of the hot
combustion gases with a hydrocarbon feedstock introduced to
the reactor portion downstream of where said dewatered and
heated off-gas is introduced in the carbon black furnace,
(d) controlling the combustion gas feed stream and oxidant gas
feed stream so that the combusting of the combustion gas feed
in the burner portion to produce hot combustion gases takes
place in a fuel-rich condition so that the combustion gas feed
stream does not completely combust in the burner portion of the
carbon black furnace, and
(e) producing carbon black in the reactor portion of the carbon
black furnace by interaction of the hot combustion gases with a
hydrocarbon feedstock under said fuel rich conditions.
The Examiner relies on the following references in rejecting the
appealed subject matter:
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Application 09/857,490

Rothbühr 4,636,375 Jan. 13, 1987
Doshi 4,690,695 Sep. 1, 1987
Sircar 5,240,472 Aug. 31, 1993
Lynum 5,527,518 Jun. 18, 1996

Claims 2-8 and 15-17 stand rejected under 35 U.S.C. § 103(a) as
follows:
I. Claims 2 and 15-17 stand rejected over Rothbühr.
II. Claims 3 and 8 stand rejected over Rothbühr in view of Sircar and
Doshi.
III. Claims 4-7 stand rejected over Rothbühr in view of Lynum.
We have thoroughly reviewed each of Appellant’s arguments for
patentability. However, we are in complete agreement with the Examiner
that the claimed subject matter would have been obvious to one of ordinary
skill in the art within the meaning of § 103 in view of the applied prior art.
Accordingly, we will sustain the Examiner's rejections.
Under 35 U.S.C. § 103, the factual inquiry into obviousness requires a
determination of: (1) the scope and content of the prior art; (2) the
differences between the claimed subject matter and the prior art; (3) the level
of ordinary skill in the art; and (4) secondary considerations. Graham v.
John Deere Co., 383 U.S. 1, 17-18 (1966). “[A]nalysis [of whether the
subject matter of a claim would have been obvious] need not seek out
precise teachings directed to the specific subject matter of the challenged
claim, for a court can take account of the inferences and creative steps that a
person of ordinary skill in the art would employ.” KSR Int’l Co. v. Teleflex,
Inc., 127 S. Ct. 1727, 1740-41 (2007) quoting In re Kahn, 441 F.3d 977, 988
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Application 09/857,490

(Fed. Cir. 2006); In re Bozek, 416 F.2d 1385, 1390 (CCPA 1969) (“Having
established that this knowledge was in the art, the examiner could then
properly rely, as put forth by the solicitor, on a conclusion of obviousness
‘from common knowledge and common sense of the person of ordinary skill
in the art without any specific hint or suggestion in a particular reference.’”);
In re Hoeschele, 406 F.2d 1403, 1406-07 (CCPA 1969) (“[I]t is proper to
take into account not only specific teachings of the references but also the
inferences which one skilled in the art would reasonably be expected to draw
therefrom . . .”).
Claims 2 and 15-17 stand rejected over Rothbühr. The Examiner
finds that Rothbühr describes a furnace carbon black producing process
comprising the steps of treating carbon black off-gas to remove water and
carbon, then recycling it. (Ans. 3). The Examiner finds that Rothbühr
suggests heating the off gas before recycling to increase the carbon yield,
and/or efficiency of combustion. The Examiner finds that Rothbühr
describes a fuel rich combustion gas feed stream. (Ans. 3).
Appellants contend that Rothbühr does not teach or suggest a fuel-rich
condition used in a carbon black producing process wherein an off-gas is
recycled as required by steps (d)-(e) of claim 15. Rather, Rothbühr teaches a
lean gas strategy for carbon black production which teaches away from the
claimed invention. (App. Br. 12-15).1
The issue presented is as follows:

1 Appellants’ arguments are limited to the utilization of fuel rich conditions.
Appellants have not argued that the remaining process steps of claim 15 are
not obvious to a person of ordinary skill in the art.
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Appeal 2008-0984
Application 09/857,490

Has the Examiner reasonably determined that a person of ordinary
skill in the art would have found it obvious to perform a furnace carbon
black producing process comprising a fuel-rich condition wherein an off-gas
is recycled, within the meaning of 35 U.S.C. § 103? On this record, we
answer this question in the affirmative.
The Specification discloses it is known to operate a furnace carbon
black production process under fuel rich conditions employing an excess of
the natural gas relative to the air or other oxidant gas stream. The
Specification discloses this process is undesirable because of
uneconomically high cost. Specifically the Specification states:
It is widely recognized that the furnace carbon black process does
not operate at desirable efficiency levels. Employing air and
natural gas as the feedstreams to the burner, efficiency typically
would not exceed sixty percent (60%) for a lean burn operation,
that is, an operation in which the natural gas is feed at less than
stoichiometric amount relative to the oxygen content of the air feed
stream. It is desirable to have the hot combustion gases produced
in the burner at temperatures sufficiently high to effect efficient
pyrolysis of the hydrocarbon feedstock, also referred to as the
"make hydrocarbon" to produce carbon black, while not having the
temperature of the combustion gases excessively high, which
could cause damage to the refractory lining of the combustion zone
and/or the reaction zone. Operating at nearly stoichiometric
conditions, with feed rates high enough to meet throughput
requirements and other necessary operating conditions, may
produce excessively high temperatures. Operating under fuel rich
conditions, that is, employing an excess of the natural gas relative
to the air or other oxidant gas stream, may produce tolerable
combustion gas temperatures coupled with improved yield, even
yield in excess of sixty percent (60%). Under such operating
conditions, however, it has been found that the raw material costs
generally are uneconomically high. Accordingly, it is typical to
operate under a fuel lean combustion strategy to achieve adequate
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throughput and tolerable raw material costs, notwithstanding the
resultant low carbon black yield.

(Spec. 1-2).
Rothbühr discloses it is known to operate a furnace carbon black
production process under a variety of conditions. Rothbühr discloses fuel
gas, combustion air, and carbon black raw material quantity are decisive
values for the operation of a carbon black reactor. Rothbühr discloses these
values are not variable arbitrarily. (Col. 1-2). Rothbühr discloses the
following limiting factors are generally controlling:
The volume of combustion air used determines the
developing volume of exhaust gas and thus fixes the through-
put of the production plant. In view of a profitable method of
operation, one will strive to realize the maximumally useable
volume of combustion air.

The fuel gas required for energy production (or some
other fuel) is mostly employed in such volumes, related to the
volume of oxygen introduced with the combustion air, that it is
present in deficiency. On the other hand, it is one of the
principles of the furnace black process that the volume of
oxygen is used in deficiency relative to the fuel and carbon
black raw material volume. Whenever one wishes to achieve
high yields, i.e., whenever as little as possible air-oxygen is to
come into contact with the carbon black raw material and is to
burn the latter, as high volumes as possible as fuel gas are used.
A 60-70% turnover of the air-oxygen with the fuel gas is a
value quite customary in practice. A limitation on the fuel gas
volume used arises primarily from the temperature resistance of
the ceramic lining because a high amount of fuel gas leads to
higher temperature loads.

Whenever one starts with a method of operation which
uses the maximum combustion air volume and the greatest
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possible fuel gas volume, then the carbon black raw material
volume is also fixed by the selection of the carbon black
quality: higher inputs of oil lead to coarser carbon black (larger
primary particle size) with higher yields, lower oil volumes on
the contrary lead to correspondingly finer carbon black (smaller
primary particle size) with lower yields.
(Col. 1, l. 39 - col. 2, l. 4).
Thus, the present record establishes that it was known to a person of
ordinary skill in the art that operating a furnace carbon black production
process under fuel rich conditions may produce tolerable combustion gas
temperatures coupled with improved yield, even yield in excess of sixty
percent (60%). (Spec. 2). The person of ordinary skill in the art would have
recognized the modifications that were required in order to operate under
fuel rich conditions. See Rothbühr which discloses that the temperature
resistance of the ceramic lining is a limitation on the fuel gas volume used in
a furnace carbon black production process. (Col. 1, ll. 57-62). Also,
Rothbühr suggests heating the off gas before recycling to increase the carbon
yield, and/or efficiency of combustion. As such, the present record reveals
that it would have been obvious to a person of ordinary skill in the art to
operate a furnace carbon black production process under either fuel rich or
fuel lean conditions and heating the off gas before recycling to increase the
carbon yield, and/or efficiency of combustion. The nature of the fuel rich
process taught by Rothbuhr would not deter a person of ordinary skill in the
art from operating its process under either fuel rich or fuel lean conditions.2

2 Appellants have not substantively and specifically argued the remaining
process limitations of the independent claim.
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Application 09/857,490

Regarding claim 2, Rothbuhr suggests that any fuel rich conditions
can be used so long as the temperature is not so high as to damage the
reactor lining.
Appellants contend that Rothbühr does not teach or suggest the
recitations of Claim 16. In support of this argument, Appellants rely on
Rothbühr’s Example 1 and the reference cited therein.
The Examiner in the answer correctly asserts that Rothbühr discloses
the recycling of off gas. (Ans. 5; Rothbühr, cols. 4 and 9). Appellants has
not challenged the Examiner’s position in the responsive Brief.
Claims 3 and 8 stand rejected over Rothbühr in view of Sircar and
Doshi. Appellants contend that Sircar and Doshi do not relate to carbon
black producing processes and do not overcome the deficiencies of
Rothbühr. According to Appellants, the Examiner has not provided proper
motivation why one skilled in the art would look to Sircar and Doshi for
PSA. (App. Br. 22-23)
We do not agree. As properly determined by the Examiner, Rothbühr
describes a furnace carbon black production process that comprises the step
of dewatering gas. Sircar and Doshi both describe dewatering gas utilizing
PSA is a known technique. (Ans. 3-4). A person of ordinary skill in the art
would have looked to the PSA techniques taught by Sircar and Doshi for the
well known purposes of dewatering gases.
Claims 4-7 stand rejected over Rothbühr in view of Lynum. The
Examiner cited Lynum for describing heating the recycle gases utilizing
plasma heating. The present record reveals that when recycling the off gas
from a carbon black production process, the gas is subject to heating. (Spec.
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Application 09/857,490

2-3). As such, a person of ordinary skill in the art would been led to reheat
the recycle gas of Rothbühr utilizing well known heating techniques,
including plasma heating. Appellants have not asserted that unexpected
results are obtained when utilizing the plasma heating technique.
For the foregoing reasons and those presented in the Answer, the
rejections of claims 2-8 and 15-17 under 35 U.S.C. § 103(a) are affirmed.
As a final point with respect to the § 103 rejection, we note that Appellants
base no argument upon objective evidence of nonobviousness, such as
unexpected results.

ORDER
The rejection of claims 2-8 and 15-17 under 35 U.S.C. § 103(a) is
affirmed.
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Application 09/857,490

No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a)(1)(iv).

AFFIRMED

tf/ls

MARTHA ANN FINNEGAN
CABOT CORPORATION
157 CONCORD ROAD
BILLERICA, MA 01821

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