Prosecution Insights
Last updated: April 19, 2026
Application No. 18/294,029

Process for Producing Liquefied Hydrogen

Non-Final OA §103§112
Filed
Jan 31, 2024
Examiner
ZEC, FILIP
Art Unit
3763
Tech Center
3700 — Mechanical Engineering & Manufacturing
Assignee
Gasconsult Limited
OA Round
1 (Non-Final)
65%
Grant Probability
Favorable
1-2
OA Rounds
3y 1m
To Grant
79%
With Interview

Examiner Intelligence

Grants 65% — above average
65%
Career Allow Rate
649 granted / 998 resolved
-5.0% vs TC avg
Moderate +14% lift
Without
With
+14.1%
Interview Lift
resolved cases with interview
Typical timeline
3y 1m
Avg Prosecution
31 currently pending
Career history
1029
Total Applications
across all art units

Statute-Specific Performance

§101
0.4%
-39.6% vs TC avg
§103
52.1%
+12.1% vs TC avg
§102
23.2%
-16.8% vs TC avg
§112
15.6%
-24.4% vs TC avg
Black line = Tech Center average estimate • Based on career data from 998 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 . Drawings The drawings are objected to under 37 CFR 1.83(a). The drawings must show every feature of the invention specified in the claims. Therefore, the “multiples of the first catalyst and the second heat exchanger” must be shown or the feature(s) canceled from the claim(s). No new matter should be entered. Corrected drawing sheets in compliance with 37 CFR 1.121(d) are required in reply to the Office action to avoid abandonment of the application. Any amended replacement drawing sheet should include all of the figures appearing on the immediate prior version of the sheet, even if only one figure is being amended. The figure or figure number of an amended drawing should not be labeled as “amended.” If a drawing figure is to be canceled, the appropriate figure must be removed from the replacement sheet, and where necessary, the remaining figures must be renumbered and appropriate changes made to the brief description of the several views of the drawings for consistency. Additional replacement sheets may be necessary to show the renumbering of the remaining figures. Each drawing sheet submitted after the filing date of an application must be labeled in the top margin as either “Replacement Sheet” or “New Sheet” pursuant to 37 CFR 1.121(d). If the changes are not accepted by the examiner, the applicant will be notified and informed of any required corrective action in the next Office action. The objection to the drawings will not be held in abeyance. 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 1-5 are 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 “essentially” in claims 1 and 5 is a relative term which renders the claim indefinite. The term “essentially” 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. It is unclear whether the composition. Claim 4 recites the limitation "one or more additional heat exchangers" in line 2. It is unclear how many heat exchangers are introduced and the limitation should read - - at least one or more additional heat exchangers - - . Claims 2 and 3 depend on claim 1 and are thus also deemed indefinite by definition. 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) 1-5 are rejected under 35 U.S.C. 103 as being unpatentable over “Integrated hydrogen liquefaction process with steam methane reforming by using liquefied natural gas cooling system” to Yang et al. (Yang) in view of U.S. Patent Application Publication 2005/0210914 to Allam et al. (Allam). In reference to claim 1, Yang teaches a process for liquefying hydrogen gas (FIG. 7 and 8) comprising providing a first stream of pure hydrogen feed gas (GH2 feed; top of FIG. 7) at a pressure of between 10 bar and 150 bar (20bar, FIG. 7); cooling the first stream in a hot passage of a first heat exchanger (first heat exchanger in the process; HX1, FIG. 7) having a first outlet stream with a temperature of between -150 °C and -210 °C (-165°C; section 3.1, page 5), admitting the first outlet stream to an assembly comprising a first catalyst (LN2 bath with catalyst, FIG. 7) for conversion of ortho-hydrogen to para-hydrogen with a second outlet stream and a second heat exchanger (HX3, FIG. 7) having a third outlet stream, the assembly comprising multiples of the first catalyst (ortho/para converters, FIG. 7) and the second heat exchanger (HX4-HX5), such that a composition of the third outlet stream is essentially para-hydrogen, with a temperature of between -210 °C and - 250 °C (37.8K, section 3.2); providing a recycle stream of hydrogen having a composition essentially of para-hydrogen and having the same pressure as the third outlet stream (from C2, top of FIG. 7, as a part of the GH2 recycle subsystem); combining the third outlet stream and the hydrogen recycle stream to form a combined stream (between HX7 and bottom LH2 bath, FIG. 7); admitting the combined stream to an expander (expansion valve, above LH2 bath, FIG. 7) having a fourth outlet stream with a pressure of between 10 bar and 1 bar and containing both liquid and vapor (section 3.1, page 5); passing the fourth outlet stream to a vessel (bottom LH2 bath, FIG. 7) wherein a liquid fraction stream, comprising the liquid hydrogen product from the process, is separated from a vapor fraction stream (section 3.1, page 5); providing the vessel with a catalyst (catalyst in bottom most LH2 bath, FIG. 7) which converts residual ortho-hydrogen in stream into para-hydrogen; reheating the vapor fraction stream in a third heat exchanger (HX6, FIG. 7) to form a fifth outlet stream, having a temperature of between -100 °C and -240 °C; admitting the fifth outlet stream to a compressor (C1 and C2, FIG. 7; compressor on top of FIG. 7); providing the compressor with a sixth outlet stream having a pressure between 10 bar and 150 bar (section 3.1, FIG. 7); and, cooling the sixth outlet stream in a fourth heat exchanger (HX2, FIG. 7; second heat exchanger from the top) having as a seventh outlet stream the aforementioned hydrogen recycle stream, but does not teach that the fifth outlet stream has a temperature between -100 °C and -240 °C. Allam shows process and apparatus for liquefying hydrogen (FIG. 1) wherein the fifth outlet stream has a temperature between -100 °C and -240 °C (par 0117) in order to match the recycled hydrogen temperature with the feed stream, prior to expanding. Therefore, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the process of Yang, to have the fifth outlet stream at a temperature between -100 °C and -240 °C, as taught by Allam, in order to match the recycled hydrogen temperature with the feed stream, prior to expanding. In reference to claim 2, Yang and Allam teach the process as explained in the rejection of claim 1 above, and Yang additionally teaches that the first catalyst in the assembly is incorporated in a hot passage of the second heat exchanger (inherent in the structure of FIG. 7). In reference to claim 3, Yang and Allam teach the process as explained in the rejection of claim 1 above, and Allam additionally teaches wherein the expander machine is split into stages in series (38, FIG. 1), whereby the third outlet stream streams and the hydrogen recycle stream are admitted at different pressures (par 0111). In reference to claim 4, Yang and Allam teach the process as explained in the rejection of claim 1 above, and Allam additionally teaches wherein one or more additional heat exchangers (24, FIG. 1) are introduced between the stages of the expander machine (38, FIG. 1). In reference to claim 5, said claim claims the limitation that are similar or are an obvious variation of the key technical features claimed in claims 1-4; thus, said claim 5 is rejected in the same manner as described in detail above. Conclusion The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. See attached PTO-892 for relevant prior art. Any inquiry concerning this communication or earlier communications from the examiner should be directed to FILIP ZEC whose telephone number is (571)270-5846. The examiner can normally be reached Mon - Fri; 9-5. 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, JD Fletcher can be reached at 5712705054. 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. /FILIP ZEC/Primary Examiner, Art Unit 3763
Read full office action

Prosecution Timeline

Jan 31, 2024
Application Filed
Nov 29, 2025
Non-Final Rejection — §103, §112 (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

1-2
Expected OA Rounds
65%
Grant Probability
79%
With Interview (+14.1%)
3y 1m
Median Time to Grant
Low
PTA Risk
Based on 998 resolved cases by this examiner. Grant probability derived from career allow rate.

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