Fritz PIERRE et al.

Patent Trials and Appeals Board

Nov 30, 2020

2020002543 (P.T.A.B. Nov. 30, 2020)

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.
15/182,050 06/14/2016 Fritz PIERRE JR. 2015EM184 6873
34477 7590 11/30/2020
ExxonMobil Upstream Research Company
22777 Springwoods Village Parkway
(EMHC-N1.4A.607)
Spring, TX 77389
EXAMINER
RAYMOND, KEITH MICHAEL
ART UNIT PAPER NUMBER
3793
NOTIFICATION DATE DELIVERY MODE
11/30/2020 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):
urc-mail-formalities@exxonmobil.com
PTOL-90A (Rev. 04/07)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
____________

Ex parte FRITZ PIERRE, JR., PARAG A. GUPTE,
RICHARD A. HUNTINGTON, and ROBERT D. DENTON

Appeal 2020-002543
Application 15/182,050
Technology Center 3700
____________

Before JENNIFER D. BAHR, JOHN C. KERINS, and
CARL M. DEFRANCO, Administrative Patent Judges.

KERINS, Administrative Patent Judge.

DECISION ON APPEAL

STATEMENT OF THE CASE

Pursuant to 35 U.S.C. § 134(a), Appellant1 appeals from the
Examiner’s decision to reject claims 1–4, 6, 8–11, 13–17, 19, and 21–25.
Claims 5, 7, 18, and 20 are canceled, and claim 12 is withdrawn. We have
jurisdiction under 35 U.S.C. § 6(b).
We AFFIRM IN PART.

1 The term “Appellant” is used herein to refer to “applicant” as defined in 37
C.F.R. § 1.42. Appellant identifies ExxonMobil Upstream Research
Company, as the real party in interest. Appeal Br. 4.
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THE CLAIMED SUBJECT MATTER
Appellant’s invention relates to a liquefied natural gas (LNG)
production system, and method of producing liquefied natural gas.
Claims 1, 4, and 6 are illustrative, and are reproduced below:
1. A liquefied natural gas production system, the system
comprising:

a natural gas stream from a supply of natural gas;

a liquefied nitrogen stream from a refrigerant supply;

at least one heat exchanger that exchanges heat between the
liquefied nitrogen stream and the natural gas stream to at least
partially vaporize the liquefied nitrogen stream, to produce an at
least partially vaporized nitrogen stream, and at least partially
condense the natural gas stream;

a natural gas compressor that compresses the natural gas stream
to a pressure of at least 135 bara to form a compressed natural
gas stream;

a natural gas cooler that cools the compressed natural gas stream
after being compressed by the natural gas compressor; and

a natural gas expander that expands the compressed natural gas
to a pressure less than 200 bara, but no greater than the pressure
to which the natural gas compressor compresses the natural gas
stream, after being cooled by the natural gas cooler;

wherein the natural gas expander is connected to the at least one
heat exchanger to supply natural gas thereto.

4. The liquefied natural gas production system of claim 1,
wherein the at least one heat exchanger comprises a first heat
exchanger, and further comprising a second heat exchanger that
cools the natural gas stream prior to the natural gas stream being
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compressed in the natural gas compressor, wherein the at least
partially vaporized nitrogen stream is used to cool the natural gas
stream in the second heat exchanger.

6. The liquefied natural gas production system of claim 1,
wherein the at least one heat exchanger comprises a first heat
exchanger, and further comprising a second heat exchanger that
cools the compressed natural gas stream prior to the compressed
natural gas stream being cooled in the natural gas cooler, wherein
the at least partially vaporized nitrogen stream is used to cool the
natural gas stream in the second heat exchanger.

THE REJECTIONS
The Examiner rejects:
(i) claims 1–3, 6, 13–16, 19, 20, and 24 under 35 U.S.C. § 103 as
being unpatentable over Christensen (WO 2015/110443 A2, published July
30, 2015) in view of Audun (US 2010/0251763 A1, published Oct. 7, 2010);
(ii) claims 4 and 17 under 35 U.S.C. § 103 as being unpatentable over
Christensen in view of Audun and Buijs (US 2009/0064713 A1, published
Mar. 12, 2009); and
(iii) claims 8–11, 21–23, and 25 under 35 U.S.C. § 103 as being
unpatentable over Christensen in view of Audun and Krishnamurthy (US
5,100,635, issued Mar. 31, 1992).
ANALYSIS
Claims 1–3, 6, 13–16, 19, 20, and 24--§ 103--Christensen/Audun
Appellant states that, for the purposes of this appeal, pertaining to this
ground of rejection, claims 1–3, 13–16, 20, and 24 stand or fall together.
Appeal Br. 13. Appellant argues separately the patentability of claims 6 and
19 as a group. Appeal Br. 15–17. We take claim 1 as representative of the
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first group, and claim 6 as representative of the second group, and discuss
each below.
Claim 1
The Examiner finds that Christensen discloses all limitations of
claim 1, including a refrigerant supply, with the exception that the
refrigerant supply is not disclosed as specifically being a liquefied nitrogen
(LIN) stream that at least partially vaporizes as a result of heat exchange
with a natural gas supply. Final Act. 4–5. The Examiner cites to the
disclosure in Auden of the use of liquid nitrogen as a refrigerant in a natural
gas liquefying system, and concludes that it would have been obvious to use
liquefied nitrogen as a vaporizing refrigerant in Christensen in order to
improve the cooling effects and require less overall refrigerant. Id. at 5. The
Examiner further points out that liquid nitrogen may be stored in smaller
tanks than may gaseous nitrogen, allowing for easier transport and holding at
the supply point. Id.
Appellant notes that Christensen employs gaseous nitrogen, and not
liquid nitrogen, and discloses that “only the heat capacity of the nitrogen gas
is used for transfer of heat, and not the phase transition between gas and
liquid.” Appeal Br. 14, quoting Christensen ¶ 28. Pointing out that gaseous
nitrogen has the capability of being used to liquefy natural gas, Appellant
argues that it would be inefficient and a waste of valuable space in the
Christensen FLNG/CLSO2 system to liquefy the nitrogen gas onboard the
system for the purpose of being used to liquefy a natural gas stream. Id.

2 FLNG is an acronym for a “Floating Liquefied Natural Gas” offshore
production facility, and CLSO is an acronym for a “Coastal Liquefaction,
Storage, and Offloading” onshore facility, on which natural gas
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In support of this position, Appellant argues that chilling a gaseous
nitrogen refrigerant to a liquid state would require larger or additional
compression systems and consume energy not only in cooling the gaseous
nitrogen, but also in producing the phase change from gas to liquid. Appeal
Br. 14. Appellant argues that all equipment, vessels, and piping used for
processing, handling, and storage of liquefied nitrogen would require
additional insulation or possibly redesign of parts of the system. Id.
Appellant concludes that “[i]t is entirely possible that the extra cost, space,
and maintenance of such modifications and replacements would more than
outweigh the smaller storage tank for the liquid nitrogen,” asserted by the
Examiner to be the reason for making the proposed modification. Id. at 14–
15. Appellant argues, in addition, that the proposed modification to use
liquefied nitrogen would not have been obvious “especially when . . .
Christensen specifically disavows its use.” Id. at 15.
The Examiner responds that much of what Appellant identifies as
potential drawbacks associated with using liquid nitrogen pertains to adding
nitrogen liquefaction equipment to the system, so as to convert vaporized,
gaseous, nitrogen back to a liquid state, and points out that this is not the
modification proposed in the obviousness rejection. Ans. 4. The Examiner
clarifies that the proposed modification to use liquefied nitrogen in the
Christensen system is to procure/purchase liquefied nitrogen from an
external source, and simply have it stored in a tank, as disclosed in Auden.
Id. The Examiner notes that Auden cites back to a much earlier issued

preprocessing is performed in order to preserve valuable space on the
FLNG. Christensen, ¶¶ 4, 10.
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patent3 as disclosing transport of liquid nitrogen (LIN) to a field site/source
of natural gas for use in cooling and liquefying natural gas to produce LNG,
which has the effect of reducing the equipment required at the field site. Id.
at 4–5, citing Auden ¶ 17. As such, Appellant’s arguments, directed to the
proposed modification requiring larger or additional compression systems
and consuming additional energy in cooling the gaseous nitrogen and
producing a phase change from gas to liquid, are not responsive to the
Examiner’s basis for the rejection.
Appellant counters that Christensen discloses that its gaseous nitrogen
is circulated in a cooling system to recool warmed gas using compressors,
air cooled heat exchangers, and LNG exchangers, and that a person of
ordinary skill in the art “could not have ignored the circulatory nature of
Christensen’s cooling system,” and would have maintained a circulatory
system even were the process modified to employ liquefied nitrogen. Reply
Br. 4. Appellant additionally maintains that, even if the circulating cooling
system were replaced, as the Examiner proposes, the existing equipment
would require additional insulation or possible redesign, as argued
previously.
“A person of ordinary skill is also a person of ordinary creativity, not
an automaton.” KSR Int'l. Co. v. Teleflex lnc., 550 U.S. 398, 421 (2007).
Appellant’s suggestion that a person of ordinary skill in the art would retain
the circulatory nature of the Christensen cooling circuit, essentially
regardless of the refrigerant chosen or considered for use, amounts to blind
adherence to the status quo, as might be expected from an automaton.
Audun discloses an approach to producing LNG that uses liquefied nitrogen

3 Williams, US 3,400,547, issued September 10, 1968.
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as a refrigerant. Particularly in view of the complications that Appellant
identifies with circulating and recooling nitrogen to liquid phase, it would
appear that a person skilled in the art looking to obtain the advantages of
using LIN as a refrigerant in an LNG process would adopt the Audun
approach of supplying the LIN from a tank, and jettison the cooling circuit
of Christensen, as proposed by the Examiner.
Appellant’s further argument that some of the equipment would
require additional insulation or some unspecified redesign in order to be
suitable for cryogenic service does not persuade us of error in the rejection.
Appellant has not established that such additional modifications, if needed,
would require greater than ordinary skill in the art. Further, “[a] given
course of action often has simultaneous advantages and disadvantages, and
this does not necessarily obviate motivation to combine.” Medichem, S.A. v.
Rolabo, S.L., 437 F.3d 1157, 1165 (Fed. Cir. 2006) (citation omitted). In the
present situation, Appellant does not dispute that the Examiner’s proposed
modification would provide the advantage of reduced storage space for the
refrigerant, but simply maintains that extra cost, space and maintenance
might possibly outweigh the benefit of having a smaller refrigerant tank.
Reply Br. 4.
Accordingly, we are not persuaded of error in the proposed
combination of references, and sustain the rejection of claim 1. Claims 2, 3,
13–16, 20 and 24 fall with claim 1.
Claim 6
Claim 6 depends from claim 1, and requires both first and second heat
exchangers, with the second heat exchanger cooling the natural gas stream
after the natural gas stream is compressed, and prior to the natural gas
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stream being cooled in a natural gas cooler. The Examiner finds that
Christensen does not disclose a first and second heat exchanger, with the
second heat exchanger functioning as set forth in claim 6, and takes the
position that it would have been obvious, in view of the presence of
“second” heat exchanger HX-101 in Audun, to add a second heat exchanger
to the Christensen system to cool the natural gas stream subsequent to
compression and prior to being cooled in a natural gas cooler, as called for in
claim 6. Final Act. 5–6. The reason advanced by the Examiner is that the
modification would maximize the use of the refrigerant and not require
additional refrigerant sources. Id. at 6.
Appellant points out that the modification proposed by the Examiner
would require the transport of the refrigerant from the FLNG offshore
facility in Christensen, where a first heat exchanger resides in component 5,
to the remote, onshore, CLSO facility, where the natural gas compressor 10
and the natural gas cooler 11 physically reside. Appeal Br. 16. Appellant
argues that the large physical separation between the FLNG and CLSO
would make sharing of the refrigerant between the two heat exchangers
impractical, and that the nitrogen refrigerant would likely lose much of its
cooling capacity during such transport. Id. The Examiner replies that the
transport of fluids, including refrigerated fluids, is commonly done in the art
and doing so between the Christensen FLNG and CLSO would have been
achieved using only ordinary skill. Ans. 7.
Appellant has the better position here. Notwithstanding the
Examiner’s broad, sweeping, generalities as to the transporting of refrigerant
fluids being within the level of ordinary skill in the art (see Answer 7),
Audun evidences that the Examiner’s proposed modification would lead to
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problems best avoided. According to Audun, “the heat exchange device is
[preferably] provided on the combined carrier. This avoids the problematic
cryogenic transfer of LNG, LCO2, and LIN between the combined carrier
and the field site, as all transfers will be in the gaseous or supercritical
phase.” Augun ¶ 39. This is in addition to the dubious alleged benefit of
exhausting all of the cooling capacity of the nitrogen refrigerant, assuming
any remains after transport from the FLNG to CLSO facility, asserted by the
Examiner.
The rejection of claim 6, and of claim 19, rejected on the same basis,
is therefore not sustained.

Claims 4 and 17--§ 103--Christensen/Audun/Buijs
Claim 4 depends from claim 1, and, similarly to claim 6, requires a
second heat exchanger to cool the natural gas stream prior to being
compressed in a natural gas compressor. Essentially the same positions are
advanced by the Examiner and Appellant for claim 4 as are presented for the
rejection of claim 6. Final Act. 6–7; Appeal Br. 17–18. The same is true of
claim 17, which includes recitations similar to claim 4. For the same reasons
discussed above with respect to claim 6, we do not sustain the rejection of
claims 4 and 17.

Claims 8–11, 21–23, and 25--§ 103--Christensen/Audun/Krishnamurthy
Appellant states that, for the purposes of this appeal, pertaining to this
ground of rejection, that claims 8–11, 21–23, and 25 stand or fall with
claim 1. Appeal Br. 14. In that we have above sustained the rejection of
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claim 1, and no other arguments are advanced for these claims relative to the
rejection lodged against them, the rejection is sustained.

CONCLUSION
The rejection of claims 1–3, 13–16, 20, and 24 under 35 U.S.C. § 103
as being unpatentable over Christensen and Audun is affirmed.
The rejection of claims 6 and 19 under 35 U.S.C. § 103 as being
unpatentable over Christensen and Audun is reversed.
The rejection of claims 4 and 17 under 35 U.S.C. § 103 as being
unpatentable over Christensen, Audun, and Buijs is reversed.
The rejection of claims 8–11, 21–23, and 25 under 35 U.S.C. § 103 as
being unpatentable over Christensen, Audun, and Krishnamurthy is
affirmed.

DECISION SUMMARY
In summary:
Claims
Rejected
35 U.S.C.
§
Reference(s)/Basis Affirmed Reversed
1–3, 6,
13–16,
19, 20, 24
103 Christensen,
Audun
1–3, 13–16,
20, 24
6, 19
4, 17 103 Christensen,
Audun, Buijs
4, 17
8–11, 21–
23, 25
103 Christensen,
Audun,
Krishnamurthy
8–11, 21–23,
25

Overall
Outcome
1–3, 8–11,
13–16, 20–25
4, 6, 17, 19

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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 IN PART