Ex Parte Evans et al

Patent Trial and Appeal Board

Oct 16, 2017

12691100 (P.T.A.B. Oct. 16, 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.
12/691,100 01/21/2010 Megan V. Evans 40978US 9089
28841 7590 10/18/2017
ConocoPhillips Company
600 North Dairy Ashford
Houston, TX 77079-1175
EXAMINER
RAYMOND, KEITH MICHAEL
ART UNIT PAPER NUMBER
3744
NOTIFICATION DATE DELIVERY MODE
10/18/2017 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):
Legal-IP@conocophillips.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte MEGAN V. EVANS, ATTILIO J. PRADERIO, and
LISAM. STRASSLE
Appeal 2015-004920
Application 12/691,100
Technology Center 3700
Before JAMES P. CALVE, GEORGE R. HOSKINS, and
ARTHUR M. PESLAK, Administrative Patent Judges.
HOSKINS, Administrative Patent Judge.
DECISION ON APPEAL
STATEMENT OF THE CASE
Megan V. Evans et al. (“Appellants”)1 appeal under 35 U.S.C. § 134
from the Examiner’s decision rejecting claims 1—24 under 35 U.S.C. § 103
as unpatentable over Hulsey (US 2007/0283718 Al, published Dec. 13,
2007) and Eaton (US 7,866,184 B2, issued Jan. 11, 2011). The Board has
jurisdiction over the appeal under 35 U.S.C. § 6(b).
We REVERSE.
1 The Appeal Brief identifies CONOCOPHILLIPS COMPANY as the real
party in interest. Br. 1.
Appeal 2015-004920
Application 12/691,100
CLAIMED SUBJECT MATTER
Claims 1 and 11 are independent. Claim 1 illustrates the claimed
subject matter, and it recites:
1 [.] A process for liquefying natural gas, said process
comprising the steps of:
a. cooling a natural gas stream in a first refrigeration cycle
employing a first refrigerant, wherein the first refrigerant cycle
includes a plurality of first refrigerant cooling stages, wherein the
natural gas stream comprises a plurality of heavy components;
b. downstream of the first refrigerant cycle, further cooling
the natural gas stream in a final refrigeration cycle employing a
final refrigerant, wherein the final refrigeration cycle is a closed
loop methane final refrigerant cycle, wherein the final refrigerant
predominately comprises less than 10 mole percent nitrogen,
wherein the final refrigeration cycle includes a plurality of final
refrigerant cooling stages, wherein the plurality of final
refrigerant cooling stages includes a first cooling stage and a final
cooling stage, wherein the temperature of the final refrigeration
cycle operates at a lower temperature than the temperature of the
first refrigeration cycle;
c. delivering the natural gas stream to a natural gas product
storage tank, wherein evaporation of a portion of the natural gas
stream occurs within the natural gas product storage tank
resulting in boil-off gas;
d. compressing [at] least a portion of the boil-off gas; and
e. delivering at least a portion of the compressed boil-off
gas from the natural gas product storage tank to the final cooling
stage of the closed loop methane final refrigeration cycle,
wherein at least a portion of the compressed boil-off gas serves
as the final refrigerant in the final cooling stage of the closed loop
methane refrigerant final refrigerant cycle.
Supplemental Appeal Brief (filed Nov. 20, 2014) (hereafter “Claims App.”),
3 (emphasis added).
2
Appeal 2015-004920
Application 12/691,100
ANALYSIS
In rejecting claim 1, the Examiner finds Hulsey’s Figure 1 illustrates a
process for liquefying natural gas substantially as claimed, except that
Hulsey’s final refrigerant cycle is not a “closed loop” methane refrigerant
cycle. Final Act. 3—5. In this regard, Hulsey describes its final refrigeration
cycle as “an open methane refrigeration cycle.” Hulsey 141 (emphases
added); see also id. 118 (differentiating between “closed” and “open”
refrigeration cycles). Concerning the boil-off limitations in claim 1, the
Examiner cites Hulsey’s disclosure that liquefied natural gas stored in
tank 99 will generate “boil-off vapors” which “are removed from tank 99 via
conduit 144” to be “compressed in compressor 96 [sic 81]” and introduced
into the methane refrigerant cycle via conduit 138. Hulsey, Fig. 1,144; see
Final Act. 5.
The Examiner finds Eaton discloses a natural gas liquefying process
that, like Hulsey’s process, delivers a portion of boil-off gas from the
liquefied natural gas stream to join with the methane refrigerant of a final
refrigerant cycle. Final Act. 5 (citing Eaton, Fig. 1, where conduit 141 and
conduit 143 join at tee 41); see also Eaton, 12:7—25 (“[predominantly
methane vapors exit separator vessel 75 via conduit 141” to be “introduced
into the predominantly methane refrigerant stream” via conduit 144). The
Examiner describes the methane refrigerant cycle of Eaton’s Figure 1 as a
“semi-closed loop” that “allows for a closed refrigeration cycle” when
valve 412 within conduit 107 is closed. Adv. Act. 2; see Eaton, Fig. 2,
9:48—10:5. The Examiner further determines “[i]t would have been obvious
to not return the methane refrigerant back to the feed stream by shutting
down the flow [through] valve [412] in order to fill up the refrigerant loop to
3
Appeal 2015-004920
Application 12/691,100
proper capacity when for example no refrigerant has yet accumulated in
vessel 400.” Adv. Act. 2.
Appellants argue the Examiner errs in finding Eaton’s Figure 1
discloses a closed loop methane refrigerant cycle, as recited in claim 1.
Br. 5. Appellants assert Eaton fails to disclose the complete closing of
valve 412, because Eaton “does not suggest that the amount of methane
refrigerant introduced back into the natural gas stream is zero.” Id.
We agree with Appellants. It is, first, important to recognize that
claim 1 is representative of all claims on appeal in reciting “[a] process for
liquefying natural gas” (Claims App. 3 (emphasis added)), not an apparatus
for liquefying natural gas. Thus, it is not sufficient for Eaton’s Figure 1 to
disclose an apparatus which is merely capable of forming a closed loop final
refrigerant cycle. In order to support the Examiner’s determination that it
would have been obvious, based on the “flow schematic and apparatus set
forth in” Eaton’s Figures 1—2 (Eaton, 6:39-44), to modify Hulsey’s process
to include a closed loop final refrigerant cycle, Eaton must disclose a process
that expressly includes the complete closing of valve 412 to support the
Examiner’s finding that Eaton, Figure 1 discloses a closed refrigeration
cycle when this condition occurs. Adv. Act. 2; see Ans. 2.
The Examiner does not cite to a preponderance of the evidence to
support such a finding. See Final Act. 5—6; Adv. Act. 2.2 The Examiner
2 The Final Office Action finds “Eaton clearly provides a closed loop.”
Final Act. 5 (emphasis added). The Advisory Action, by contrast, finds
“Eaton clearly teaches a semi-closed loop which provides a valve structure
that allows for a closed refrigeration cycle.” Adv. Act. 2 (emphases added)
We resolve this apparent inconsistency in understanding that the Advisory
4
Appeal 2015-004920
Application 12/691,100
finds Eaton merely “allows for a closed refrigeration cycle” by the complete
closing of valve 412. Adv. Act. 2. As just discussed, that finding is, by
itself, insufficient. We agree with Appellants that the Eaton process
disclosed in connection with the flow schematic and apparatus of Figures 1—
2 does not include the complete closing of valve 412. See Eaton, 9:48—10:5
(disclosing that flow control unit 406 receives level indicator signal 404 and,
in response, “automatically adjust[s]” valves 412 and 416 to maintain an
appropriate amount of methane refrigerant within vessel 400).
The Examiner goes on to determine it would have been obvious to
close valve 412 completely, even if such complete closure is not expressly
disclosed by Eaton, in order “to not return the methane refrigerant back to
the feed stream [at 118 etc.]” and thereby “fill up the refrigerant
loop [at 105 etc.] to proper capacity when for example no refrigerant has yet
accumulated in vessel 400.” Adv. Act. 2. This determination does not
provide a rational underpinning sufficient to support the legal conclusion of
obviousness. See In re Kahn, 441 F.3d 977, 988 (Fed. Cir. 2006), cited with
approval in KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398, 418 (2007). Eaton
indicates that vessel 400 may be filled with refrigerant even without the
complete closure of valve 412. Eaton, 9:48—10:5. Thus, the need to fill
vessel 400 does not provide a rational basis for modifying the Eaton
liquefaction process such that valve 412 would be completely closed,
thereby cutting off the flow of refrigerant to mix with the natural gas within
Action explains the basis for the initial finding in the Final Office Action,
namely, that Eaton discloses a closed loop by virtue of the capability of
valve 412 to be closed.
5
Appeal 2015-004920
Application 12/691,100
conduit 118, which mixing serves the function of helping to liquefy the
natural gas.
Alternatively to relying on Eaton’s Figure 1—2 as disclosing a closed
loop cycle, the Examiner finds that closed loop methane final refrigerant
cycles were well known in the art, citing Appellants’ Specification at
paragraph 7 and Eaton’s disclosure at column 1, lines 54—60. Adv. Act. 2;
Ans. 2—3. The Examiner finds “the interchangeability and distinct
advantages of closed and open loop refrigeration systems” were known to
persons of ordinary skill in the art. Adv. Act. 2; Ans. 5 (citing Eaton, 1:54—
60, 2:1—21). The Examiner determines it would have been obvious to
modify Hulsey’s open loop final methane refrigerant cycle to be a closed
loop final methane refrigerant cycle, while continuing to utilize the boil-off
vapors from the liquefied natural gas stored in tank 99 to supplement the
methane refrigerant. Adv. Act. 2; Ans. 2—3. This would have been done,
according to the Examiner, “to save and reutilize the methane and not waste
refrigerant as is done in open cycles,” and/or “to avoid utilizing external
methane to replace lost refrigerant which can lead to unnecessary costs
wherein available process methane can instead be utilized.” Final Act. 6.
Appellants contend that while it may be the case that closed loop
systems were known in the prior art, a person of ordinary skill in the art
would not operate Hulsey as a closed loop system, “given the type of
refrigerant being utilized” in Hulsey. Br. 6.
We determine the Examiner does not provide a rational underpinning,
supported by a preponderance of the evidence, sufficient to support the
conclusion that a person of ordinary skill in the art would have modified
Hulsey’s open methane refrigerant cycle to be a closed methane refrigerant
6
Appeal 2015-004920
Application 12/691,100
cycle. In particular, the Examiner has not cited evidence to establish that
Hulsey’s open methane refrigerant cycle either “waste[s]” the methane
refrigerant or “utilizes] external methane to replace lost refrigerant.” See
Final Act. 6. That is, these might be problems in some open refrigerant
cycles, but the Examiner has not explained sufficiently why these would
have been problems in Hulsey’s open refrigerant cycle. Our review of
Hulsey, instead, indicates that all of the methane refrigerant is either
(a) recycled back through the refrigeration loop, or (b) supplied to the
natural gas stream being liquefied and eventually stored within tank 99 for
later usage. Either way, the refrigerant is used, not wasted. Furthermore,
the Examiner does not cite, and we cannot find, any disclosure in Hulsey
indicating Hulsey’s process requires introducing any methane refrigerant,
apart from what is taken from the natural gas stream via conduit 125.
Compare Hulsey, Fig. 1 (failing to disclose where methane might be
introduced into the methane refrigerant loop other than conduit 125), with
Spec. 135 & Fig. 2 (conduit 123 introduces methane refrigerant into
methane refrigerant loop). And, as already discussed, the natural gas
diverted via Hulsey’s conduit 125 either remains within the refrigerant loop
or is stored in tank 99 for later usage.
The Examiner, more generally, also finds “the interchangeability and
distinct advantages of closed and open loop refrigeration systems” were well
known, so it would have been obvious to change Hulsey’s open loop to be a
closed loop. See, e.g., Adv. Act. 2; Ans. 5 (citing Eaton, 2:1—21). This
finding is insufficient to establish obviousness by, again, not providing a
reason why modifying Hulsey’s open loop to be a closed loop would have
provided an advantage. The cited Eaton disclosure discusses some
7
Appeal 2015-004920
Application 12/691,100
disadvantages of some closed loop systems (Eaton, 2:1—10), and some
disadvantages of some open loop systems {id. at 2:10-21). However, the
Examiner does not explain how the identified general disadvantages of some
open loops would apply to Hulsey’s open loop, or explain how modifying
Hulsey’s open loop to be a closed loop would improve upon any such
applicable disadvantages.
For the foregoing reasons, we do not sustain the rejection of claim 1
as having been obvious over Hulsey and Eaton. The Examiner’s additional
consideration of the other rejected claims 2—24 does not cure the noted
deficiency as to claim 1. See Final Act. 6—9. We, therefore, likewise do not
sustain the rejection of those claims as having been obvious over Hulsey and
Eaton.
DECISION
The rejection of claims 1—24 as having been obvious over Hulsey and
Eaton is reversed.
REVERSED
8