Prosecution Insights
Last updated: April 19, 2026
Application No. 17/901,347

SOLID OXIDE FUEL CELL PLACEMENT IN GAS TURBINE COMBUSTOR

Non-Final OA §103
Filed
Sep 01, 2022
Examiner
EGGERDING, ALIX ECHELMEYER
Art Unit
1729
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Arizona Board of Regents
OA Round
3 (Non-Final)
58%
Grant Probability
Moderate
3-4
OA Rounds
3y 9m
To Grant
75%
With Interview

Examiner Intelligence

Grants 58% of resolved cases
58%
Career Allow Rate
440 granted / 764 resolved
-7.4% vs TC avg
Strong +17% interview lift
Without
With
+17.3%
Interview Lift
resolved cases with interview
Typical timeline
3y 9m
Avg Prosecution
35 currently pending
Career history
799
Total Applications
across all art units

Statute-Specific Performance

§101
0.3%
-39.7% vs TC avg
§103
61.8%
+21.8% vs TC avg
§102
17.0%
-23.0% vs TC avg
§112
15.4%
-24.6% vs TC avg
Black line = Tech Center average estimate • Based on career data from 764 resolved cases

Office Action

§103
DETAILED ACTION Notice of Pre-AIA or AIA Status The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . Response to Amendment This Office Action is in response to the amendment filed 1/23/26. Claim Rejections - 35 USC § 103 In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status. The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action: A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made. Claims 41-49 are rejected under 35 U.S.C. 103 as being unpatentable over Viteri et al. (US 2002/0174659) in view of Hoffjann et al. (US 2015/0017557) and as evidenced by Ahn et al. (US 2014/0363776). Regarding claim 41, Viteri teaches a method of operating fuel cell, the method comprising: separating air at the air separator to yield nitrogen and oxygen gas flows (Figure 4); providing the oxygen-containing gas flow to a fuel cell (SOFC); combusting the oxygen-containing gas in the combustor (Figure 4); and recovering heat from the fuel cell is provided to the combustor. Further regarding claim 41, Figure 4 of Viteri does not depict recovered heat provided to the air separator. However, in Figure 2 of Viteri, it is seen that heat recovered from the fuel cell, i.e. exit stream of fuel cell at 1800-1900°F, where the recovered heat, via the fuel cell exit stream, further flows through the system where it is exchanged with incoming air provided to the air separator, or ion transfer membrane air separator (see arrows in annotated Figure 2, below). PNG media_image1.png 547 609 media_image1.png Greyscale Viteri additionally discusses, in multiple portions of the specification, recovering heat from the fuel cell directly and other components of the system for heating other parts of the system (see, e.g. [0038], [0040], [0042]). The examiner finds that it would have been obvious to the person having ordinary skill in the art to rearrange components of the system of Viteri in Figure 4 such as suggested in Viteri Figure 2 in order to provide recovered heat to the air separator. The skilled artisan will understand that using heat generated within the system is desirable for increasing the overall efficiency of the system, and in light of [0045] of Viteri, which suggests that modifications based on disclosures in the application are within the ordinary level of skill in the art, it would have been obvious to use recovered heat from the turbine, which in turn uses heat from the fuel cell system, to heat the air separation in order to increase the efficiency of the system. Further, the skilled artisan will easily understand that such a rearrangement of parts would result in improved efficiency of the system. It has been held that rearrangement of parts is within the ordinary level of skill in the art. MPEP 2144.04 VI C With further regard to claim 41, while Viteri teaches a solid oxide fuel cell including a first combustor, or pre-burner, and a second combustor, or after-burner, Viteri does not specifically call the system a flame-assisted fuel cell. Ahn teaches a flame-assisted solid oxide fuel cell including a first combustor, or 1st stage, where fuel is processed, and a second combustor, or 2nd stage, where byproducts are combusted (Figure 1, [0016]). Since the solid oxide fuel cell of Viteri has all of the components of the flame-assisted fuel cell of Ahn, the examiner finds that the fuel cell of Viteri is a flame-assisted solid oxide fuel cell. With further regard to claim 41, Viteri teaches that the recovered heat is used in electricity generated in the fuel cell, since the incoming oxidant is heated by the heat and then used in the fuel cell reaction, an outcome of which is the generation of electricity (Figure 4). Viteri fails to teach specifically that the electricity, and therefore recovered heat, are used to power the separating of air. Hoffjann teaches a fuel cell system including an air separator, or gas splitter, that is powered by electricity generated in the fuel cell in order to simplify the overall system ([0019]). Therefore, it would have been obvious to the skilled artisan at the time of the invention to power the air separator of Viteri with electricity generated in the fuel cell such as suggested by Hoffjann in order to simplify the overall system. As for claims 42, 44, and 46, as discussed above, Viteri teaches a pre-burner, or first combustor, upstream of the fuel cell and an after-burner, or reheater, downstream of the fuel cell, wherein the after-burner processes, or combusts, an exhaust stream (Figure 4). Viteri further teaches that the heat from the after-burner, or reheater, is used in the turbines to drive the generator ([0025]). Regarding claims 43 and 45, it is seen in Figure 4 of Viteri that methane, or CH4, is provided to the pre-burner, or combustor, as well as hydrogen, carbon dioxide, carbon monoxide, and water. As for claim 47, it is seen in Figure 4 of Viteri that water is removed from the exhaust stream leaving the low pressure turbine. With regard to claims 48-49, it is seen in Figure 4 of Viteri that, after water is removed, carbon dioxide is compressed and sequestered. Claims 51-52 are rejected under 35 U.S.C. 103 as being unpatentable over Viteri in view of Munoz de Escalona et al. (“The Potential of the Supercritical …) and Weingaertner et al. (US 2020/0168922) and as evidenced by Ahn. The teachings of Viteri and Ahn as discussed above are incorporated herein. Regarding claim 51, Viteri teaches a flame-assisted fuel cell as discussed above with regard to claim 41, including an air separation unit and flame-assisted fuel cell. With further regard to claim 51, Viteri teaches sequestration of carbon dioxide but fails to teach specifically a supercritical gas turbine system. Munoz de Escalona teaches that supercritical carbon dioxide turbine systems are desirably used in fuel cell systems, such as molten carbonate or solid oxide, as a substitute for conventional turbines in order to increase the efficiency of the system (abstract, Figure 3). It would have been obvious to the skilled artisan at the time of the invention to substitute a supercritical carbon dioxide system to the system of Viteri for the conventional turbine system such as suggested by Munoz de Escalona in order to increase the efficiency of the system. Viteri additionally teaches an embodiment in which the heat from a turbine within the system is used to heat the air separation (see annotated Figure 2, above). The skilled artisan will understand that using heat generated within the system is desirable for increasing the overall efficiency of the system, and in light of [0045] of Viteri, which suggests that modifications based on disclosures in the application are within the ordinary level of skill in the art, it would have been obvious to use recovered heat from the turbine, which in turn uses heat from the fuel cell system, to heat the air separation in order to increase the efficiency of the system. Further regarding claim 51, Viteri in view of Munoz de Escalona fails to teach a precooler as claimed. Weingaertner teaches a fuel cell system including a precooler, or anode cooler (100), wherein the system is configured to recover heat rejected from the precooler and provide the recovered heat to an air inlet stream via air pre-heater (100) (Figure 16). Weingaertner further teaches that using the hot exhaust, which is precooled prior to further use in the system, to cool the air inlet stream is desirable to increase overall flow conditions in the system ([0065]). It would have been obvious to the skilled artisan at the time of the invention to include a precooler in the system of Viteri in view of Munoz de Escalona such as suggested by Weingaertner in order to increase overall flow conditions in the system and, as discussed above, to use heat generated within the system for increasing the overall efficiency of the system. As for claim 52, the supercritical carbon dioxide system of Munoz de Escalona teaches a heat exchanger (HX4) in communication with the fuel cell system (Figure 3). Claims 53-63 are rejected under 35 U.S.C. 103 as being unpatentable over Viteri in view of Munoz de Escalona as applied to claim 52 above, and further in view of Kang et al. (US 2016/0010513). The teachings of Viteri and Munoz de Escalona as discussed above are incorporated herein. Regarding claims 53 and 59, Viteri in view of Munoz de Escalona teaches the system of claim 52 but fails to teach the specifically claimed components of the supercritical carbon dioxide system. Kang teaches a supercritical carbon dioxide system for use in a hybrid power generation system (abstract). The system of Kang includes: first (240) and second (222) compressors compressing first and second streams of carbon dioxide; first (252) and second (250) recuperators preheating the carbon dioxide stream in the same manner as instant Figure 8 (Figure 1 of Kang). Kang further teaches that the supercritical carbon dioxide system discussed above is desirable for realizing optimal efficiency ([0010]). Therefore, it would have been obvious to use the supercritical carbon dioxide system of Kang in the system of Viteri in view of Munoz de Escalona in order to realize optimal efficiency. Further regarding claim 53, Kang further teaches a heat exchanger (210) for further heating the second preheated stream of carbon dioxide (Figure 1). It would have been obvious to use the heat exchanger of Viteri in view of Munoz de Escalona as the heat exchanger 210 of Viteri in view of Munoz de Escalona and Kang since both are heat exchangers. As for claims 54-57, Kang teaches a turbine (220) in fluid communication via the second recuperator (250) with the processed stream of carbon dioxide which is then provided to the first recuperator (252) (Figure 1). Regarding claims 58 and 60-61, Kang teaches a precooler (230) (Figure 1). As for claim 62, it is seen in Figure 1 of Kang that the second carbon dioxide stream (8) meets the first (7) between the recuperators. With regard to claim 63, Viteri teaches a pre-burner, or first combustor, upstream of the fuel cell and an after-burner, or reheater, downstream of the fuel cell (Figure 4). Response to Arguments The arguments filed 10/23/25 are addressed in the office action mailed 2/4/26. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to ALIX ECHELMEYER EGGERDING whose telephone number is (571)272-1101. The examiner can normally be reached 8:30am - 4:30pm. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Ula Ruddock can be reached at 571-272-1481. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /ALIX E EGGERDING/Primary Examiner, Art Unit 1729
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Prosecution Timeline

Sep 01, 2022
Application Filed
Dec 16, 2022
Response after Non-Final Action
May 29, 2025
Non-Final Rejection — §103
Sep 02, 2025
Response Filed
Sep 17, 2025
Interview Requested
Sep 18, 2025
Interview Requested
Sep 25, 2025
Examiner Interview Summary
Oct 21, 2025
Final Rejection — §103
Jan 23, 2026
Response after Non-Final Action
Feb 07, 2026
Interview Requested
Feb 23, 2026
Examiner Interview Summary
Feb 23, 2026
Applicant Interview (Telephonic)
Mar 02, 2026
Non-Final Rejection — §103 (current)

Precedent Cases

Applications granted by this same examiner with similar technology

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2y 5m to grant Granted Mar 10, 2026
Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

3-4
Expected OA Rounds
58%
Grant Probability
75%
With Interview (+17.3%)
3y 9m
Median Time to Grant
High
PTA Risk
Based on 764 resolved cases by this examiner. Grant probability derived from career allow rate.

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