Ex Parte Franz et al

Board of Patent Appeals and Interferences

Mar 12, 2009

10794130 (B.P.A.I. Mar. 12, 2009)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte MARCUS FRANZ and JURGEN KUNZEL
____________

Appeal 2008-4928
Application 10/794,130
Technology Center 1700
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Decided:1 March 13, 2009
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Before EDWARD C. KIMLIN, CHUNG K. PAK, and ROMULO H.
DELMENDO, Administrative Patent Judges.

PAK, Administrative Patent Judge.

DECISION ON APPEAL

Appellants appeal under 35 U.S.C. § 134 from the Examiner’s
decision finally rejecting claims 1 through 12, 27, and 28, all of the claims

1 The two-month time period for filing an appeal or commencing a civil
action, as recited in 37 C.F.R. § 1.304, begins to run from the Decided Date
shown on this page of the decision. The time period does not run from the
Mail Date (paper delivery) or Notification Date (electronic delivery).
Appeal 2008-4928
Application 10/794,130

pending in the above-identified application. We have jurisdiction under 35
U.S.C. § 6.
STATEMENT OF THE CASE
The subject matter on appeal is directed to “a process for preparing
hydrogen chloride” (Spec. 1, ll. 7-8). Details of the appealed subject matter
are recited in representative claim 12 reproduced below:
1. A process for preparing hydrogen chloride, which comprises
the steps of:

reacting feed gases, being chlorine with water vapor, in an
endothermic reaction with heat being supplied in a first process step in a first
reactor to give a mixture of hydrogen chloride and oxygen; and

in a second reactor, a second process step, adding a reducing agent to
convert the chlorine which has not been reacted in the first process step into
hydrogen chloride in an exothermic reaction that produces heat and to bind
the oxygen formed in the first process step to the reducing agent; and

transferring the heat produced in the second step from the second
reactor to provide the heat needed in the first process step in the first reactor.

As evidence of unpatentability of the claimed subject matter, the
Examiner has proffered the following prior art references:
Durst DE 199 39 951 A1 Mar. 8, 20013
Nanda et al. (Nanda), “The Kinetics of the Reverse Deacon Reaction,” in 13
Int’l Journal of Hydrogen Energy 67-76 (1988).

2 Appellants have presented substantive arguments directed to the limitations
set forth in claim 1 only. Therefore, for the purposes of this appeal, we limit
our discussion to claim 1 only pursuant to 37 C.F.R. §41.37(c)(1)(vii)(2007),
3 Our reference to this published German Patent Application is to the
corresponding English translation of record.
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The Examiner has finally rejected claims 1 through 12, 27, and 28
under 35 U.S.C. § 103(a) as unpatentable over the combined disclosures of
Nanda and Durst.

ISSUE
Have Appellants identified any reversible error in the Examiner’s
determination that:
1) One of ordinary skill in the art would have been led to employ
the conventional hydrogen chloride producing combustion reactor taught by
Durst after Nanda’s reverse Deacon reaction, with a reasonable expectation
of successfully increasing the production of hydrogen chloride and
minimizing the release of chlorine (a toxic substance) into the atmosphere
within the meaning of 35 U.S.C. § 103(a); and
2) One of ordinary skill in the art would have been led to utilize
the heat recovered from the conventional hydrogen chloride producing
combustion process taught by Durst to at least partially heat Nanda’s reverse
Deacon reaction (an endothermic reaction requiring heat), with a reasonable
expectation of successfully and efficiently utilizing the recovered heat within
the meaning of 35 U.S.C. § 103(a)?

FINDINGS OF FACT
The Factual Findings set forth below are supported by a
preponderance of the evidence:
1. Nanda teaches a reverse Deacon reaction process in which chlorine
(Cl2) and steam (H2O) are preheated at 175 to 200o C and then reacted at a
temperature of about 879 K (606o C) to produce an effluent gas containing
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hydrogen chloride (HCl) and oxygen (Compare Nanda, pp. 67-68 and 71-72,
and Fig. 4 with Appellants’ claims 1, 2, and 4).
2. Nanda teaches that its reverse Deacon reaction liberates oxygen from
water and is a known source for hydrogen production (pp. 67-68).
3. Nanda teaches that the effluent gas resulting from the reverse Deacon
reaction contains unreacted chlorine, in addition to hydrogen chloride and
oxygen (p. 68).
4. Appellants do not dispute the Examiner’s finding that Nanda’s reverse
Deacon reaction is an endothermic reaction (heat absorbing reaction
requiring an outside heat source). (Compare Ans. 4, with App. Br. 4-11 and
Reply Br. 4-6).
5. Appellants do not specifically challenge the Examiner’s official notice
that “it is well known in the art that the [reverse Deacon] reaction as stated
above is an equilibrium reaction and a catalyst is known to be used to
produce chlorine from hydrogen chloride” (Compare Ans. 5 with App. Br.
4-11 and Reply Br. 4-6).
6. Appellants do not dispute the Examiner’s conclusion that it would
have been obvious to one skilled in the art to use the known catalyst recited
in claims 10 and 12 in the reverse Deacon process taught by Nanda
(Compare Ans.5 with App. Br. 4-11 and Reply Br. 4-6).
7. Nanda is silent as to treating the effluent gas further with a reducing
gas (e.g., hydrogen or methane) to remove chlorine and produce additional
hydrogen chloride, and utilizing the heat produced from such further
treatment in its reverse Deacon reaction process (see generally Nanda).
8. Appellants do not dispute the Examiner’s finding that chlorine is a
toxic material (Compare Ans. 5 with App. Br. 4-11 and Reply Br. 4-6).
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9. Appellants acknowledge that further treating an effluent gas
containing hydrogen chloride, oxygen, and chlorine from a first hydrogen
chloride producing reaction stage with a reducing agent in a second stage
was known to be used to ensure “virtually complete removal of the oxygen
from the offgas and reaction of the chlorine to hydrogen chloride” (Spec. 4-
5).
10. Durst also teaches a reaction system useful for producing hydrogen
chloride by combusting an effluent gas containing chlorine, oxygen, and a
hydrogen source, such as methane, propane, etc., (corresponding to those
recited in Appellants’ claim 6) in a porous burner (p. 14) .
11. Durst in reference to Figures 6 and 7 describes a system for producing
hydrogen chloride, comprising combusting in a porous burner a mixture of
hydrogen, chlorine, fuel (e.g., methane), oxidant, and a portion of the
reaction product stream resulting therefrom (e.g., hydrogen chloride, etc.),
recovering heat from the reaction product stream, recycling a portion of the
reaction product stream to the porous burner, and treating the other part of
the reaction product stream to recover hydrogen chloride (pp. 19-20 and
Figs. 6-7).
12. Appellants do not dispute the Examiner’s finding that Durst’s
combustion reaction is an exothermic reaction (heat producing or generating
reaction) (Compare Ans. 5 with App. Br. 4-11 and Reply Br. 4-6).
13. Durst teaches (p. 19) that:
The reaction products [from the porous burner 1] move from
here via a line 27 into a heat exchanger 28 for cooling. The
heat exchanger can be cooled with water, for example.
Alternatively, utilization of the heat is also possible by
generating hot water or low pressure steam there for further use.

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14. Durst teaches (p. 20) that:
It goes without saying that other gases such as inert gases or
water vapor can also be supplied for temperature regulation, if
the external conditions require this. If the combustion
temperature is lower than the predetermined target value, the
calorific power must be increased by supplying natural gas.

15. Appellants have not proffered any persuasive evidence to show that
the conventional hydrogen chloride producing combustion reaction of the
type taught by Durst is unpredictable. (See generally App. Br. and Reply
Br.)

PRINCIPLES OF LAW
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, if necessary.
Graham v. John Deere Co., 383 U.S. 1, 17-18 (1966). According to KSR
Int’l Co. v. Teleflex, Inc., 127 S. Ct. 1727, 1740-41 (2007):
[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.

See also DyStar Textilfarben GmbH & Co. Deutschland KG v. C.H. Patrick
Co., 464 F.3d 1356, 1361 (Fed. Cir. 2006) (“The motivation need not be
found in the references sought to be combined, but may be found in any
number of sources, including common knowledge, the prior art as a whole,
or the nature of the problem itself.”); In re Hoeschele, 406 F.2d 1403, 1406-
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407 (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”). The common
knowledge attributable to one of ordinary skill in the art includes what was
admittedly known in the art by Appellants at the time of the invention. See
In re Nomiya, 509 F.2d 566, 570-71 (CCPA 1975) (The admitted prior art in
applicant’s Specification may be used in determining the patentability of a
claimed invention.); see also In re Davis, 305 F.2d 501, 503 (CCPA 1962).
KSR, 127 S. Ct. at 1740-42 (partly quoting Sakraida v. Ag Pro, Inc.,
425 U.S. 273, 282 (1976)) further instructs that:
[W]hen a patent “simply arranges old elements with each
performing the same function it had been known to perform”
and yields no more than one would expect from such an
arrangement, the combination is obvious. . . .
. . . .
When there is a design need or market pressure to solve a
problem and there are a finite number of identified, predictable
solutions, a person of ordinary skill has good reason to pursue
the known options within his or her technical grasp. If this
leads to the anticipated success, it is likely the product . . . of
ordinary skill and common sense.

In re Fulton, 391 F.3d 1195, 1201 (Fed. Cir. 2004) states that “[t]he
prior art’s mere disclosure of more than one alternative does not constitute a
teaching away from any of these alternatives because such disclosure does
not criticize, discredit, or otherwise discourage the solution claimed in the …
application.”
The burden is on Appellants to identify reversible error in the
appealed § 103 rejection. Cf. In re Kahn, 441 F.3d 977, 985-986 (Fed. Cir.
2006); see also 37 C.F.R. § 41.37(c)(1)(vii).
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ANALYSES AND CONCLUSIONS OF LAW
As indicated supra, Nanda describes a hydrogen chloride producing
endothermic reaction (reverse Deacon reaction) process in which chlorine
and steam are reacted to produce an effluent gas containing hydrogen
chloride, unreacted chlorine, oxygen, and possibly hydrogen. This
endothermic reaction (reverse Deacon reaction) process, according to
Nanda, is useful for producing oxygen and hydrogen from water, in addition
to producing hydrogen chloride. Nanda does not mention treating the
effluent gas containing hydrogen chloride, unreacted chlorine, and oxygen
resulting from its endothermic reaction (reverse Deacon reaction) process
further with a reducing gas (e.g., hydrogen or methane) and utilizing the heat
produced from such further treatment in its endothermic reaction (reverse
Deacon reaction) process.
However, Durst teaches an exothermic combustion reaction process
for combusting an effluent gas containing hydrogen chloride, oxygen,
chlorine, and reducing gases to produce a product stream containing more
hydrogen chloride and recovering the heat from such product stream for
further use. Appellants also acknowledge that the combustion reaction of
the type taught by Durst is known for further treating an effluent gas
containing hydrogen chloride, oxygen, and chlorine from a first hydrogen
chloride producing reaction stage to ensure the virtually complete removal
of oxygen and chlorine in the effluent gas. Moreover, Appellants do not
challenge the Examiner’s finding that chlorine is a toxic substance.
Given the above teachings, we concur with the Examiner that one of
ordinary skill in the art would have been led to employ the conventional
hydrogen chloride producing combustion reactor taught by Durst to treat the
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effluent gas from Nanda’s reverse Deacon reaction reactor, with a
reasonable expectation of successfully increasing the production of
hydrogen chloride and minimizing the emission of chlorine (a toxic
substance) into the atmosphere. One of ordinary skill in the art would also
have been led to utilize the heat recovered from the conventional combustion
process taught by Durst to at least partially heat Nanda’s reverse Deacon
reaction (an endothermic reaction requiring heat), motivated by a reasonable
expectation of successfully maximizing the recovered waste heat. As stated
in KSR, 127 S. Ct. at 1740 (quoting Sakraida, 425 U.S. at 282:
[W]hen a patent “simply arranges old elements with each
performing the same function it had been known to perform”
and yields no more than one would expect from such an
arrangement, the combination is obvious.

In reaching these determinations, we have considered Appellants’
argument relating to the unpredictable nature of employing the conventional
hydrogen chloride producing combustion process taught by Durst to treat the
effluent gas from Nanda’s reverse Deacon reaction. However, as is apparent
from the discussion above, combusting the effluent of the type produced in
Nanda’s reverse Deacon reaction to produce hydrogen chloride and, at the
same time, minimize or prevent a toxic substance, chlorine, from being
released into the environment is well known. Appellants have not proffered
any persuasive evidence to show that the conventional hydrogen chloride
producing combustion process of the type taught by Durst is unpredictable.
Appellants’ “teaching-away” argument relating to the recovery of
waste heat is equally unsupported by factual evidence. Nowhere does Durst
criticize, discredit, or otherwise discourage one of ordinary skill in the art
from recovering waste heat from its exothermic combustion reaction for the
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purpose of reusing it in a location where heat is needed. In fact, Durst
specifically teaches recovering the heat from the product stream resulting
from Durst’s conventional exothermic combustion process for further
utilization.
Accordingly, based on the reasons set forth in the Answer and above,
we determine that the preponderance of evidence weighs most heavily in
favor of obviousness within the meaning of 35 U.S.C. § 103(a).

ORDER
In view of the foregoing, the decision of the Examiner is affirmed.

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

AFFIRMED

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