Ex Parte IIDA et al

Board of Patent Appeals and Interferences

May 27, 2003

09022817 (B.P.A.I. May. 27, 2003)

1
The opinion in support of the decision being entered today was
not written for publication and is not binding precedent of the
Board.
Paper No. 29
UNITED STATES PATENT AND TRADEMARK OFFICE
_____________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
_____________
Ex parte KOZO IIDA,
TORU TAKASHINA and SHINTARO HONJO
_____________
Appeal No. 2002-0864
Application 09/022,817
______________
ON BRIEF
_______________
Before KIMLIN, PAK, and PAWLIKOWSKI, Administrative Patent
Judges.
PAK, Administrative Patent Judge.
DECISION ON APPEAL
This is a decision on an appeal under 35 U.S.C. § 134
from the examiner’s refusal to allow claims 1 and 2, which are
all of the claims pending in the above-identified application.
Appeal No. 2002-0864
Application 09/022,817

2
APPEALED SUBJECT MATTER
The subject matter on appeal is directed to a process
for treating a combustion exhaust gas containing NOx, SOx and
mercury wherein a specific amount of a mercury chlorinating
agent, together with ammonia, is added to the combustion exhaust
gas in the presence of a particular denitrating catalyst to
remove nitrogen oxides while simultaneously converting mercury-
containing compounds to mercury chlorides. See the specifica-
tion, pages 6 and 7. Details of the appealed subject matter are
illustrated in representative claim 1 which is reproduced below:
1. A process for treating combustion exhaust gas
comprising:
adding a mercury chlorinating agent and ammonia to
combustion exhaust gas containing Nox, Sox, and mercury to carry
out removal of nitrogen oxides from the exhaust gas in the
presence of a solid catalyst comprising: (1) a carrier comprised
of at least one compound selected from the group consisting of
TiO2, SiO2, ZrO2, and zeolite, and (2) at least one element
selected from the group consisting of Pt, Ru, Ir, V, W, Mo, Ni,
Co, Fe, Cr, Cu, and Mn, wherein said element is carried by said
carrier, and wherein the mercury chlorinating agent is added in
an amount greater than the stoichiometric amount relative to the
mercury present in the exhaust gas to produce a mercury chloride;
and
wet-desulfurizing the denitrated exhaust gas using an
alkaline absorbing unit.
Appeal No. 2002-0864
Application 09/022,817

1 Our reference to the published German and Japanese patent
applications is to their corresponding English translations of
record.
3
PRIOR ART
The examiner relies on the following prior art
references:1

Kubisa DE 42 08 355 A1 Sep. 23, 1993
(Published German Patent Application)

Tabata et al. (Tabata) JP 6-126134-A May 10, 1994
(Published Japanese Patent Application)
Kato et al. (Kato) JP 6-319950-A Nov. 22, 1994
(Published Japanese Patent Application)
Appellants’ admission at pages 2 and 3 of the specification in
reference to prior art Figure 3 (hereinafter referred to as
“admitted prior art”).
The appellants rely on the following literature:
Jumpei Ando, “Review of Japanese NOx Abatement Technology for
Stationary Sources,” NOx-Symposium Karlsruhe 1985, pp. A1-A42
(hereinafter referred to as “Ando”).

REJECTION
Claims 1 and 2 stand rejected under 35 U.S.C. § 103 as
unpatentable over the combined teachings of the admitted prior
art, Kubisa, Kato and Tabata.
We reverse.
Appeal No. 2002-0864
Application 09/022,817

4
The examiner properly finds (Answer, page 5) that:
The Applicants’ description of the prior
art set forth on pg. 2 to pg. 3 in their
specification discloses a method for treating
combustion exhaust gas from a boiler,
comprising:
adding ammonia to the combustion exhaust
gas so that the ammonia can react with and
remove nitrogen oxides out of the combustion
exhaust gas;
subjecting the4 [sic, the] exhaust gas
to a wet desulfurizing unit so that sulfur
oxides and mercury chloride can be removed
out of the gas.
According to the examiner (Answer, page 6), both Kato and Tabata
teach that the above nitrogen oxide removal (conventional
denitrating step) is normally carried out in the presence of the
claimed denitrating catalyst. We find that both Kato and Tabata
teach that nitrogen oxides are removed from a combustion exhaust
gas with ammonia in the presence of the claimed denitrating
catalyst at a temperature below 600oC. See Kato, pages 18/27
and 21/27 and Tabata, pages 12/17 and 14/17.
The dispositive question is whether it would have been
prima facie obvious to add a specific amount of a mercury
chlorinating agent, together with ammonia, to a combustion
Appeal No. 2002-0864
Application 09/022,817

5
exhaust gas in the presence of a specific denitrating catalyst
to convert mercury compounds therein to mercury chlorides, while
simultaneously removing nitrogen oxides. On this record, we
answer this question in the negative.
As found by the examiner (Answer, page 5), Kubisa
discloses treating a combusted waste gas containing at least
sulfur dioxide, hydrogen chloride, and mercury with an added
amount of a mercury chlorinating agent, i.e., hydrogen chloride,
to remove mercury in the form of mercury chlorides at a
temperature of 800 to 850°C. See also Kubisa, pages 1-3.
Kubisa discloses that converting mercury into mercury chloride
allows the efficient and effective removal of the mercury content
in the waste gas possible. See pages 2-3. According to Kubisa
(page 6), the resulting waste gas can then be further treated to
remove sulfur oxides and nitric oxides.
Given the similarity between the waste gas and the
admittedly known power furnace boiler gas above (Brief, page 5),
we concur with the examiner that the prior art references as a
whole would have provided sufficient suggestion and/or motivation
to employ a mercury chlorinating agent, such as hydrogen
Appeal No. 2002-0864
Application 09/022,817

6
chloride, in the admittedly known method as modified and/or
explained by Kato and Tabata. However, we determine that the
combined teachings of these prior art references would not have
resulted in the claimed invention inasmuch as they would have
suggested the desirability of converting mercury and/or mercury
compounds in a boiler gas to mercury chloride before denitrating
it in the presence of ammonia and a specific denitrating
catalyst.
In reaching this determination, we have also considered
the teachings of Ando relied upon by both the examiner and the
appellants. See the Answer, page 8, and the Brief, pages 4-5.
While Ando teaches and/or suggests that a temperature applicable
to a non-catalytic denitration reaction step (reacting nitrogen
oxides with ammonia in the absence of a catalyst) is equally
applicable to a temperature for converting mercury/mercury
compounds into mercury chloride (chlorination)(see page A39),
it does not teach or suggest that both the above-mentioned
chlorination and denitration reactions can be carried out
simultaneously in the presence of a specific denitration catalyst
(see Ando in its entirety). Specifically, the examiner has not
Appeal No. 2002-0864
Application 09/022,817

2 Indeed, as indicated supra, both Kato and Tabata teach
that a catalytic denitration step involving the claimed catalysts
is desirably carried out at a temperature below 600oC which is
much below the mercury chlorination temperature suggested by
Kubisa.
3 Since no prima facie case is established, we need not
address the sufficiency of the secondary evidence proffered by
the appellants. See, e.g., In re Piasecki, 745 F.2d 1468, 1472,
223 USPQ 785, 788 (Fed. Cir. 1984).
7
demonstrated that the temperature range taught by Ando to be
useful for a non-catalytic denitrating step is also applicable to
the admittedly known catalytic denitration step as explained
and/or modified by Kato and Tabata.2 Nor has the examiner
demonstrated that one of ordinary skill in the art would have
reasonably expected to obtain the same or similar chlorination
reaction taught by Kubisa in the presence of, inter alia, the
claimed denitration catalyst.
On this record, the examiner simply has not established
a prima facie case of obviousness regarding the claimed subject
matter within the meaning of 35 U.S.C. § 103.3 Accordingly, we
reverse the aforementioned Section 103 rejection.
Appeal No. 2002-0864
Application 09/022,817

8
The decision of the examiner is reversed.
REVERSED
EDWARD C. KIMLIN )
Administrative Patent Judge )
)
)
) BOARD OF PATENT
CHUNG K. PAK ) APPEALS AND
Administrative Patent Judge ) INTERFERENCES
)
)
)
BEVERLY A. PAWLIKOWSKI )
Administrative Patent Judge )
CKP:psb
Appeal No. 2002-0864
Application 09/022,817

9
Myers Bigel Sibley & Sajoveck
P.O. Box 37428
Raleigh, NC 27627