Prosecution Insights
Last updated: April 19, 2026
Application No. 18/374,636

PROCESS FOR REPLACEMENT OF FOSSIL FUELS IN FIRING OF ROTARY LIME KILNS

Non-Final OA §103§112
Filed
Sep 28, 2023
Examiner
ROBINSON, RENEE E
Art Unit
1772
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Highbury Energy Inc.
OA Round
1 (Non-Final)
74%
Grant Probability
Favorable
1-2
OA Rounds
2y 11m
To Grant
97%
With Interview

Examiner Intelligence

Grants 74% — above average
74%
Career Allow Rate
759 granted / 1029 resolved
+8.8% vs TC avg
Strong +24% interview lift
Without
With
+23.5%
Interview Lift
resolved cases with interview
Typical timeline
2y 11m
Avg Prosecution
35 currently pending
Career history
1064
Total Applications
across all art units

Statute-Specific Performance

§101
0.4%
-39.6% vs TC avg
§103
43.3%
+3.3% vs TC avg
§102
14.9%
-25.1% vs TC avg
§112
29.2%
-10.8% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1029 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, claims 1, 3, 5, 8, 11, 12 and 14-17, in the reply filed on 13 February 2026 is acknowledged. The traversal is on the ground(s) that the examiner has failed to establish that a search of the complete application would be an undue burden. This is not found persuasive because consideration of the claim groups together would require additional searching which would not be required by consideration of the elected group alone, including additional classification and fields of search. The requirement is still deemed proper and is therefore made FINAL. Claim Interpretation The office notes that “coarse particulates” and “fine particulates” are terms of art and are not unclear. They are interpreted herein as relative in size in comparison to each other and are not necessarily bound by any particular size limitations, i.e. coarse particulates are larger in size than fine particulates. 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, 5, 8, 11, 12 and 14-17 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. Regarding claim 1, the phrase "such as" renders the claim indefinite because it is unclear whether the limitations following the phrase are part of the claimed invention. See MPEP § 2173.05(d). The term “hot” in claim 1 is a relative term which renders the claim indefinite. The term “hot” 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 from the context of the claims and corresponding specification what temperature would be considered “hot.” The term “cool” in claim 1 is a relative term which renders the claim indefinite. The term “cool” 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 from the context of the claims and corresponding specification what temperature would be considered “cool.” Claim 14 recites the limitation "the lower heating value" in line 1. There is insufficient antecedent basis for this limitation in the claim. Claim Rejections - 35 USC § 103 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. This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention. Claims 1, 3, 5, 8, 11, 12 and 14-17 are rejected under 35 U.S.C. 103 as being unpatentable over Daggupati et al (US 2015/0361362) in view of Apanel et al (US 8,241,523) and Vandergriendt et al (US 2014/0004471). Regarding claims 1, 5, 8, 11, 12, 14 and 17, Daggupati discloses a system comprising a dual bed gasification apparatus comprising (see Abstract; Fig. 1; [0071]-[0074]): a fluidized bed gasifier 102 (see [0039]); a circulating fluidized bed char combustor 140 connected to the gasifier (via 128, 132) (see [0041]); a heat carrier circulating between the gasifier and the char combustor (see [0039]-[0041]); a gasifier cyclone 104 connected to the gasifier; a gasifier heat exchanger 106 connected to the gasifier cyclone; a gas passage 130 to deliver cooled syngas; a char combustor cyclone 144; and a char combustor heat exchanger 150. Daggupati does not explicitly disclose: (1) baghouses or other separation devices downstream of the cyclones; (2) a liquid scrubber or other separation device; and (3) wherein the gas passage delivers syngas to a kiln burner. Regarding (1), it is noted that Daggupati mentions “necessary purification” prior to downstream applications (see [0074]), but not the specifics thereof. In this regard, reference is drawn to Apanel, which, like Daggupati, is directed to dual fluidized bed gasification. Apanel discloses implementing units downstream of cyclones associated with the gasifier and the combustor, respectively, including a candle filter (i.e., “other separation device”) and a baghouse which are capable of a finer degree of particle separation from syngas and flue gas produced in the gasifier and combustor, respectively (see col. 13, line 67 – col. 14, line 2; col. 18, lines 11-18; col. 29, lines 63-67). It would have been obvious to a person of ordinary skill in the art at the time of filing the instant claimed invention to modify the apparatus of Daggupati to implement devices downstream of the cyclones, such as a candle filter and baghouse, as suggested by Apanel, in order to improve overall separation of fine material from the gas streams. Regarding (2), Apanel further discloses a scrubber on the syngas line downstream from gasification to remove impurities therefrom and provide a high quality syngas (see col. 13, lines 46-56; col. 16, line 65 – col. 17, line 7). It would have been obvious to a person of ordinary skill in the art at the time of filing the instant claimed invention to modify the apparatus of Daggupati by including a scrubber on the syngas line, as suggested by Apanel, in order to remove residual impurities and provide a high quality syngas product. Regarding (3), Vandergriendt discloses that syngas produced from gasification of biomass may be fed to a syngas burner. Specifically, the syngas burner may be used to direct-fire a device requiring a relatively high flame temperature, such as a lime kiln (see Abstract; [0009]). Syngas generated from materials such as biomass in a gasifier can be used to fully or partially replace fossil fuels conventionally used to fire burners for lime kilns (see [0016]). It would have been obvious to a person of ordinary skill in the art at the time of filing the instant claimed invention to connect the syngas passage of Daggupati to a burner for a kiln, as suggested by Vandergriendt, where Vandergriendt establishes that such sources of syngas are suitable for use thereof and furthermore are beneficial for replacing conventionally used fossil fuel sources typically used for such purpose. The combination of references is considered to fully teach and/or suggest the structural features of the claimed apparatus. The remaining limitations pertain to the material worked upon by and the intended use of the claimed apparatus and are not structurally limiting. MPEP 2114 & 2115. The office notes, however, that a suitable feed material in Daggupati is biomass (see [0065]). Regarding claim 3, Daggupati discloses a steam source 122 for the gasifier (see [0073]). Regarding claims 15 and 16, Apanel discloses a dryer upstream of the gasifier in order to reduce the moisture content of feed biomass material to a desired level. The dryer uses heat from combustor flue gas (see col. 27, line 54 – col. 28, line 20). Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to RENEE ROBINSON whose telephone number is (571)270-7371. The examiner can normally be reached Monday - Thursday 8:00a-5:00p and Friday 8:00a-2:00p. 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, In Suk Bullock can be reached at (571)272-5954. 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. /Renee Robinson/Primary Examiner, Art Unit 1772
Read full office action

Prosecution Timeline

Sep 28, 2023
Application Filed
Mar 06, 2026
Non-Final Rejection — §103, §112 (current)

Precedent Cases

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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
74%
Grant Probability
97%
With Interview (+23.5%)
2y 11m
Median Time to Grant
Low
PTA Risk
Based on 1029 resolved cases by this examiner. Grant probability derived from career allow rate.

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