Prosecution Insights
Last updated: April 19, 2026
Application No. 18/043,232

PROCESS AND APPARATUS FOR PRODUCING LOW-NITROGEN SYNTHESIS GAS FROM NITROGEN-CONTAINING NATURAL GAS

Non-Final OA §103§112
Filed
Feb 27, 2023
Examiner
MCCLAIN, STARFARI TESHAWN
Art Unit
1736
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Linde GmbH
OA Round
1 (Non-Final)
92%
Grant Probability
Favorable
1-2
OA Rounds
3y 4m
To Grant
99%
With Interview

Examiner Intelligence

Grants 92% — above average
92%
Career Allow Rate
24 granted / 26 resolved
+27.3% vs TC avg
Moderate +9% lift
Without
With
+8.7%
Interview Lift
resolved cases with interview
Typical timeline
3y 4m
Avg Prosecution
13 currently pending
Career history
39
Total Applications
across all art units

Statute-Specific Performance

§101
5.1%
-34.9% vs TC avg
§103
53.3%
+13.3% vs TC avg
§102
27.0%
-13.0% vs TC avg
§112
14.6%
-25.4% vs TC avg
Black line = Tech Center average estimate • Based on career data from 26 resolved cases

Office Action

§103 §112
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 . Election/Restrictions Applicant's election with traverse of Group I in the reply filed on 11/04/2025 is acknowledged. The traversal is on the ground(s) that the technical feature claimed involves the use at least a part of the low-nitrogen, water-free and carbon dioxide-free natural gas, prior to its thermochemical conversion, as regenerating gas in the regeneration of the first and/or second temperature swing adsorption plants. This is not found persuasive because while the Ernst does not explicitly use low-nitrogen, water-free and carbon dioxide-free natural gas as regeneration gas, Doong teaches a small portion of the fully treated natural gas is shown sent back (16) to the TSA unit as a regeneration stream (Doong, [0014], Fig 1). The combination of these known elements would have been obvious regeneration is standard practice for maintaining efficiency in the process. The requirement is still deemed proper and is therefore made FINAL. Claims 6-10 withdrawn from further consideration pursuant to 37 CFR 1.142(b), as being drawn to a nonelected invention, there being no allowable generic or linking claim. Applicant timely traversed the restriction (election) requirement in the reply filed on 11/04/2025. Claim Rejections - 35 USC § 112 The following is a quotation of 35 U.S.C. 112(b): (b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention. The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph: The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention. Claims 1-3 and 14-15 is rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention. The term “low-nitrogen” in claims 1-3 and 14-15 is a relative term which renders the claim indefinite. The term “low-nitrogen” is not defined by the claim, the specification does not provide a standard for ascertaining the requisite degree, and one of ordinary skill in the art would not be reasonably apprised of the scope of the invention. The amount of nitrogen in the claimed gas mixtures has been rendered indefinite. 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. The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows: 1. Determining the scope and contents of the prior art. 2. Ascertaining the differences between the prior art and the claims at issue. 3. Resolving the level of ordinary skill in the pertinent art. 4. Considering objective evidence present in the application indicating obviousness or nonobviousness. Claim(s) 1-2, 4-5, and 12-14 is/are rejected under 35 U.S.C. 103 as being unpatentable over Ernst (US 7879919 B) and further in view of Doong (US 20110315010 A1) and Jadhav (US 8926941 B2) . With respect to claim 1, the claim requires “A process for producing a low-nitrogen synthesis gas from a natural gas containing nitrogen and carbon dioxide.” Ernst teaches producing hydrocarbons from natural gas that contains nitrogen, carbon dioxide, and sulphur-containing compounds (Ernst, abstract; Ernst 1, line 27-33). Claim 1 further requires “removing water and carbon dioxide in a first temperature swing adsorption plant and subsequently removing nitrogen in a cryogenic gas fractionator, to give a low-nitrogen, water-free and carbon dioxide-free natural gas” Ernst teaches knocking out liquid and removing CO2 from the natural gas in the pre-treatment stage using a temperature swing adsorption(Ernst 1, line 65-Ernst 2, line 2). Ernst further teaches a cryogenic gas separation stage to separate an inert stream including nitrogen and argon (Ernst 1, line 47-51). Claim 1 further requires “obtaining the low-nitrogen synthesis gas by removal of water and carbon dioxide from the crude syngas in a second temperature swing adsorption plant.” Ernst teaches a producing a low-nitrogen synthesis gas which includes at least CO, H2 , nitrogen, and carbon dioxide and nitrogen (Ernst 1, line 14-30, line 50-51). Ernst does not explicitly teach a second temperature swing adsorption plant for removing the carbon dioxide and liquids from the crude syngas. However, Jadhav teaches a synthesis gas wherein the gas is dried and the CO2 in a temperature swing adsorption plant (Jadhav 2, line 45-67- 3; Jadhav 3, line 1-45). It would have been obvious to a person having ordinary skill in the art before the effective filing date of the invention to have, by the method of Ernst, a second temperature swing adsorption plant for removing the carbon dioxide and liquids from the syngas, as Jadhav teaches the desirable result of producing a high purity hydrogen product (Jadhav, abstract). Claim 1 further requires “at least a part of the low-nitrogen, water-free and carbon dioxide-free natural gas prior to its thermochemical conversions is used as regenerating gas in regeneration of the first temperature swing adsorption plant and/or regeneration of the second temperature swing adsorption plant.” Ernst does not explicitly teach a part of the low-nitrogen, water-free and carbon dioxide-free natural gas prior to its thermochemical conversions is used as regenerating gas in regeneration. However, Doong teaches a small portion of the fully treated natural gas is shown sent back (16) to the TSA unit as a regeneration stream (Doong, [0014], Fig 1). It would have been obvious to a person having ordinary skill in the art before the effective filing date of the invention to have, by the method of Ernst, natural gas prior to its thermochemical conversions used as regenerating gas in regeneration of the first/second temperature swing adsorption plant as Doong teaches this additional treatment is to obtain a preferred amount of product gas (Doong, abstract, [0008], [0014]). Regarding claim 2, the process according to claim 1 has been discussed above. Doong teaches regeneration gas from the TSA unit, which contains the non-condensable CO2 is recycled back to the inlet of the membrane or further processed by a combination of membrane and TSA units (Doong, [0012]). Claim 2 further requires “wherein the at least part of the low-nitrogen, water-free and carbon dioxide-free natural gas used as regenerating gas is fed to the thermochemical conversion together with substances desorbed during adsorber regeneration.” Ersnt teaches low-nitrogen, water-free and carbon dioxide-free natural gas. Ersnt does not explicitly teach natural gas used as regenerating gas is fed to the thermochemical conversion together with substances desorbed during adsorber regeneration. However, Doong teaches a small portion of the fully treated natural gas is shown sent back (16) to the TSA unit as a regeneration stream (Doong, [0014]). It would have been obvious to a person having ordinary skill in the art before the effective filing date of the invention to have, by the method of Ersnt, to have natural gas used as regenerating gas to fed to the thermochemical conversion as Doong teaches this allows for more efficient removal of contaminants from the regeneration effluent gas (Doong, [0029]). Regarding claim 4, Ernst teaches a pretreatment step for the removal of CO2 (Ernst 2, line 3-11). Regarding claim 5, Ernst teaches the reforming stage may be or may include an autothermal reforming stage, a partial oxidation stage, or a combined autothermal reforming (Ernst 2, line 55-61). Regarding claim 12, Ernst teaches pretreatment of natural gas by removing CO2 from natural gas using an amine scrubbing solution (Ernst 2, line 3-11). Regarding claim 13, the process according to claim 4 has been discussed above. Claim 13 further requires” wherein the part of the carbon dioxide present in the natural gas containing nitrogen and carbon dioxide that is removed upstream of the first temperature swing adsorption plant is used in the thermochemical conversion.” Doong teaches regeneration gas from the TSA unit, which contains the non-condensable CO2 is recycled back to the inlet of the membrane or further processed by a combination of membrane and TSA units (Doong, [0012]). Regarding claim 14, Ernst teaches the reforming stage may be or may include an autothermal reforming stage, a partial oxidation stage, or a combined autothermal reforming (Ernst 2, line 55-16). Claim(s) 11 is/are rejected under 35 U.S.C. 103 as being unpatentable over Ernst (US 7879919 B), Doong (US 20110315010 A1), and Jadhav (US 8926941 B2) as applied to claims 1-2, 4-5, and 12-14 above, and further in view of Ballantyne (US 20150209717 A1). Regarding claim 11, the process according to claim 4 has been discussed above. Further requires “wherein regeneration of the first temperature swing adsorption plant and/or regeneration of the second temperature swing adsorption plant is conducted at a temperature between 170 and 230°C” Ernst does not explicitly teach temperature of first/second swing adsorption plants. However, Ballantyne teaches regenerating the adsorbent to a temperature of about 80 °C to about 200 °C. It would have been obvious to a person having ordinary skill in the art before the effective filing date of the invention to have, by the method of Ernst, the regeneration temperature range claimed as Ballantyne teaches effective removal of siloxane and other contaminants from gas streams (Ballantyne, [0089]) in this temperature range. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to STARFARI TESHAWN MCCLAIN whose telephone number is (571)272-0169. The examiner can normally be reached M-F 8 AM- 5 PM. 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, Anthony Zimmer can be reached at (571) 270-3591. 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. /STARFARI TESHAWN MCCLAIN/ Examiner, Art Unit 1736 /ANTHONY J ZIMMER/ Supervisory Patent Examiner, Art Unit 1736
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Prosecution Timeline

Feb 27, 2023
Application Filed
Jan 08, 2026
Non-Final Rejection — §103, §112 (current)

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Prosecution Projections

1-2
Expected OA Rounds
92%
Grant Probability
99%
With Interview (+8.7%)
3y 4m
Median Time to Grant
Low
PTA Risk
Based on 26 resolved cases by this examiner. Grant probability derived from career allow rate.

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