Ex Parte McElroy et al

Patent Trial and Appeal Board

Aug 4, 2017

11491487 (P.T.A.B. Aug. 4, 2017)

United States Patent and Trademark Office
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
Address: COMMISSIONER FOR PATENTS
P.O.Box 1450
Alexandria, Virginia 22313-1450
www.uspto.gov
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
11/491,487 07/24/2006 James McElroy 7917-218 3346
22208 7590 08/08/2017
The Marbury Law Group, PLLC
11800 SUNRISE VALLEY DRIVE
15TH FLOOR
RESTON, VA 20191
EXAMINER
THOMAS, BRENT C
ART UNIT PAPER NUMBER
1724
NOTIFICATION DATE DELIVERY MODE
08/08/2017 ELECTRONIC
Please find below and/or attached an Office communication concerning this application or proceeding.
The time period for reply, if any, is set in the attached communication.
Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the
following e-mail address(es):
ptonotices @marburylaw.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte JAMES McELROY,
SWAMINATHAN VENKATARAMAN,
JOHN FINN, M. DOUGLAS LeVAN,
and FRED MITLITSKY
Appeal 2016-003360
Application 11/491,487
Technology Center 1700
Before ADRIENE LEPIANE HANLON, N. WHITNEY WILSON, and
SHELDON M. McGEE, Administrative Patent Judges.
HANLON, Administrative Patent Judge.
DECISION ON APPEAL
A. STATEMENT OF THE CASE
The Appellants filed an appeal under 35 U.S.C. § 134 from an Examiner’s
decision rejecting claims 1—6 and 25—30. We have jurisdiction under 35 U.S.C.
§ 6(b).
We REVERSE.
The claims on appeal are directed to a method of operating a fuel cell
system. Claim 1 is reproduced below from the Claims Appendix of the Appeal
Brief dated August 20, 2015 (“App. Br.”). The limitations at issue are italicized.
Appeal 2016-003360
Application 11/491,487
1. A method of operating a fuel cell system, comprising:
providing a fuel inlet stream into a fuel cell stack;
operating the fuel cell stack to generate electricity, an air
exhaust stream and a fuel exhaust stream, the fuel exhaust stream
having a temperature above 200 C and a first composition
immediately after leaving the fuel cell stack;
heating the fuel inlet stream with the entire fuel exhaust stream
in a fuel heat exchanger,
heating a fuel cell stack air inlet stream with an output of the
fuel heat exchanger in an air preheater heat exchanger;
splitting the fuel exhaust stream into a first split fuel exhaust
stream and a second split fuel exhaust stream such that the first and
second split fuel exhaust streams have the same first composition;
lowering a temperature of at least the entire of the first or
second split fuel exhaust streams to 200 C or less;
recycling the first split fuel exhaust stream into the fuel inlet
stream; and
burning the second fuel exhaust stream with the air exhaust
stream, wherein heating the fuel inlet stream is performed prior to
burning the second fuel exhaust stream',
wherein neither the fuel exhaust stream, the first split fuel
exhaust stream nor the second split fuel exhaust stream is passed
through a water gas shift reactor.
App. Br. 14.
The Examiner maintains the following grounds of rejection on appeal:
(1) claims 1, 2, and 25—29 under 35 U.S.C. § 103(a) as unpatentable over
Kelly et al.1 in view of Gottmann et al.;2
1 US 2006/0263657 Al, published November 23, 2006 (“Kelly”).
2 US 2004/0191598 Al, published September 30, 2004 (“Gottmann”).
2
Appeal 2016-003360
Application 11/491,487
(2) claims 3—6 under 35 U.S.C. § 103(a) as unpatentable over Kelly in
view of Gottmann, and further in view of Keefer;3 and
(3) claim 30 under 35 U.S.C. § 103(a) as unpatentable over Kelly in view
of Gottmann, and further in view of Reiser et al.4
B. DISCUSSION
The Examiner finds Kelly discloses a method of operating a fuel cell system
as recited in claim 1 with the exception that Kelly does not teach heating the fuel
inlet stream (i.e., from fuel tank 12) with the entire fuel exhaust stream (streams 62
and 53) in a fuel heat exchanger. Non-Final 4.5 Kelly Figure 1 is reproduced
below.
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FIG. 1.
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Kelly Figure 1 is a schematic drawing of an
embodiment of a solid oxide fuel cell stack system.
3 US 2005/0106429 Al, published May 19, 2005 (“Keefer”).
4 US 2004/0157094 Al, published August 12, 2004 (“Reiser”).
5 Non-Final Action dated May 21, 2015.
3
Appeal 2016-003360
Application 11/491,487
The Examiner finds that in the same field of endeavor, Gottmann teaches
heating a fuel inlet stream (in conduit 56) with a fuel exhaust stream (in conduit
58) in fuel heat exchanger 54. Non-Final 4. Gottmann Figure 5 is reproduced
below.
Gottmann Figure 5 is a schematic drawing of the
major components of a solid oxide regenerative fuel cell.
The Examiner concludes that it would have been obvious to one of ordinary
skill in the art “to use the fuel heat exchange method of Gottman [sic] with the
method of Kelly for the benefit of releasing waste heat from the exhaust gas to the
inlet gas.” Non-Final 5; see also Non-Final 3 (finding that Gottmann’s heat
exchanger “would provide the benefit of a separate source of heat in addition to the
post-combustor heat exchanger [58] of Kelly”).
The Appellants provide a modified Kelly Figure 1, reproduced below,
showing the modification proposed by the Examiner (i.e., a heat exchanger at the
4
Appeal 2016-003360
Application 11/491,487
outlet of fuel cell stack 38 upstream of split fuel exhaust streams 62 and 53).6
Reply Br. 3.7
Modified Kelly Figure 1 is a schematic drawing showing
Gottmann’s heat exchanger at the outlet of
solid oxide fuel cell stack 38.
The Appellants argue that “there is no reason to add the heat exchanger of
Gottmann to the method of Kelly because the heat exchanger of Gottmann is
duplicative of the existing heat exchanger 58 of Kelly.” App. Br. 5. That is, the
Appellants argue that in Kelly’s system:
The first portion 53 of the fuel exhaust of Kelly is provided to a
combustor 52 and then the combustor 52 exhaust stream is provided
to the heat exchanger side 58 of the reformer 36. The combusted first
portion 53 of the fuel exhaust stream then exchanges heat with the
6 The position of Gottmann’s heat exchanger in Kelly’s system satisfies the
limitation in claim 1 that the fuel inlet stream is heated prior to burning the second
fuel exhaust stream with the air exhaust stream as, for example, in a combustor.
7 Reply Brief dated February 12, 2016.
5
Appeal 2016-003360
Application 11/491,487
fuel inlet stream in the heat exchanger side 58 of the reformer
exchanges.
App. Br. 6.
In response, the Examiner finds:
[T]he fuel heat exchanger of Gottman [sic] operates differently than
the heat exchanger of Kelly. The fuel heat exchanger of Gottman
[sic] is the closest device to the fuel cell of Gottman [sic] along the
fuel inlet and outlet streams and uses the heat from the exiting fuel
exhaust stream to heat entering fuel inlet stream [0042, fig. 5]. Since
this exchange consumes no fuel it provides an efficient way to heat the
incoming fuel using the waste heat from the exhaust fuel. When
combined with the fuel cell device of Kelly this additional fuel heat
exchanger would allow for more efficient heating of the incoming fuel
since it does not rely upon combustion to provide heat.
Ans. 6 (emphasis added).8
The Appellants argue:
[I]f the heat exchanger of Gottmann is . . . located, [as proposed by the
Examiner,] then both split streams 53 and 62 will have less heat and
be at a lower temperature than split streams 53 and 62 in the system of
Kelly absent the additional heat exchanger [of Gottmann], Thus, in
the combined system as proposed by the Examiner, reduced heat is
provided to the combustor 52 as discussed in the Appeal Brief....
Thus, in the proposed combined system, ... the combustor 52 . . .
receive[s] less heat.
Reply Br. 3; see also App. Br. 9 (arguing that if Gottmann’s heat exchanger 54
were located as proposed by the Examiner, “the fuel exhaust stream exiting heat
exchanger 54 and entering combustor 52 would be at a lower temperature than the
fuel exhaust stream 53 of Kelly which enters the combustor 52 directly from the
fuel cell stack 38”).
8 Examiner’s Answer dated December 16, 2015.
6
Appeal 2016-003360
Application 11/491,487
The Appellants argue that in Kelly’s modified system, additional heat would
be added, such as by providing additional fuel to combustor 52. However, the
Appellants argue that “[djoing so . . . would negate the alleged benefit from adding
a heat exchanger that “consumes no fuel” as suggested by the Examiner. Reply Br.
4.
The Appellants’ argument is persuasive of reversible error. The Examiner
finds that adding Gottmann’s heat exchanger upstream of combustor 52 “provides
an efficient way to heat the incoming fuel using the waste heat from the exhaust
fuel.” Ans. 6. In Kelly’s modified system, however, fuel inlet stream 12/37 is not
only heated in Gottmann’s heat exchanger upstream of combustor 52 but also is
heated in reformer 36/heat exchanger 58 downstream of combustor 52. Kelly 117.
In the modified system, a reduced-temperature fuel exhaust stream 53 enters
combustor 52, and a hot exhaust gas stream exiting combustor 52 supplies heat to
the fuel inlet stream at heat exchanger side 58 of reformer 3 6.9 The Examiner does
not explain, in any detail, why Kelly’s modified system, which comprises two heat
exchangers (one upstream of compressor 52 and one downstream of compressor
52) “provides an efficient way to heat the incoming fuel.” Ans. 6. For that reason,
the Examiner has failed to show that modifying Kelly’s system as proposed
“would allow for more efficient heating of the incoming fuel.” See Ans. 6.
The § 103(a) rejection of claims 1, 2, and 25—29 is not sustained.
The Examiner does not rely on Keefer or Reiser to cure the deficiency in the
rejection of claim 1 identified above. Therefore, the § 103(a) rejections of claims
3—6 and 30 also are not sustained.
9 The heated fuel inlet stream subsequently enters fuel cell stack 38 at the location
of reference numeral 37 in Kelly Figure 1.
7
Appeal 2016-003360
Application 11/491,487
C. DECISION
The Examiner’s decision is reversed.
REVERSED
8