Prosecution Insights
Last updated: April 19, 2026
Application No. 17/780,696

TWO-STEP PROCESS FOR CONVERTING LIQUEFIED WASTE PLASTICS INTO STEAM CRACKER FEED

Non-Final OA §103§112
Filed
May 27, 2022
Examiner
NGUYEN, TAM M
Art Unit
1771
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Neste Oyj
OA Round
2 (Non-Final)
78%
Grant Probability
Favorable
2-3
OA Rounds
2y 9m
To Grant
88%
With Interview

Examiner Intelligence

Grants 78% — above average
78%
Career Allow Rate
746 granted / 963 resolved
+12.5% vs TC avg
Moderate +11% lift
Without
With
+10.9%
Interview Lift
resolved cases with interview
Typical timeline
2y 9m
Avg Prosecution
68 currently pending
Career history
1031
Total Applications
across all art units

Statute-Specific Performance

§101
0.1%
-39.9% vs TC avg
§103
51.2%
+11.2% vs TC avg
§102
16.7%
-23.3% vs TC avg
§112
18.7%
-21.3% vs TC avg
Black line = Tech Center average estimate • Based on career data from 963 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 . Response to Amendment The rejection of claims 16-30 under 35 USC § 103 is withdrawn by the examiner in view of the amendment filed on 12/29/2026. A New non-final Office Action is follows. 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 16-30 and 33 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. Step (B) of claim 16 is rendered the claim indefinite because it is unclear what is fed into the liquid-liquid separation. 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. 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. Claim 16-28 and 33 are rejected under 35 U.S.C. §103(a) as being unpatentable over Narayanaswamy et al., US 2018/0002609 A1 in view of Akimoto et al., “Hydrothermal Denitrogenation of Fuel Oil Derived from Municipal Waste Plastics in a Continuous Packed-Bed Reactor” Ind. Eng. Chem. Res. (2003) and in view of Hajekova et al. “Copyrolysis of naphtha with polyalkene cracking products; the influence of polyalkene mixtures composition on product distribution” ScienceDirect, pyrolysis 79 (2007) pages 196-204. Narayanaswamy teaches providing a liquid hydrocarbon stream derived from mixed waste plastics via pyrolysis, i.e., a “second stream comprising hydrocarbons having 5 or more carbon atoms,” and feeding that stream together with hydrogen into a hydrocracker to obtain a hydrotreated/hydrocracked liquid product that is supplied to a steam cracker (Narayanaswamy ¶¶ [0005], [0011]–[0015], [0017], [0019]). Narayanaswamy does not tech step B as claimed. Akimoto teaches pre-treating fuel oil derived from thermally degraded waste plastics by contacting the oil with an aqueous alkaline medium (aqueous NaOH, pH ≥ 7) at subcritical hydrothermal temperatures of 250–325 °C (≥200 °C), followed by separating the organic layer from the aqueous phase, i.e., liquid–liquid separation, to obtain a treated oil (Akimoto, Experimental Section; Results & Discussion). Akimoto does not teach a post-treatment as claimed. Hájeková teaches post-treatment conditioning of plastic-derived cracking products by blending them with heavy naphtha, a paraffinic material, to form a steam-cracking feedstock (Hájeková, Abstract; pp. 196–197). It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to combine Akimoto’s alkaline hydrothermal pretreatment with Narayanaswamy’s hydrotreating/steam-cracking integration and Hájeková’s paraffinic blending to remove contaminants, protect downstream catalysts, and condition plastic-derived oils for steam cracking, with a reasonable expectation of success. Claim 17 Narayanaswamy expressly teaches feeding the hydroprocessed liquid stream to a steam cracker to produce light olefins (Narayanaswamy ¶¶ [0005], [0011]–[0015]). Claims 18–23 Narayanaswamy teaches reduction of chloride content in plastic-derived streams, including targets of ≤10 ppm and <1 ppm chloride in downstream streams, and teaches hydrocracking to saturate olefins prior to cracking (Narayanaswamy ¶¶ [0016], [0023], [0070]–[0074]; Examples 6–8). Akimoto teaches that alkaline hydrothermal processing of plastics-derived oils removes heteroatoms including chlorine and nitrogen at ≥200 °C using aqueous NaOH (Akimoto, Results & Discussion; Figures 2–4). Selection of specific contaminant or olefin content ranges and steam-cracker-feed properties represents routine result-effective optimization of known pretreatment and hydroprocessing steps. Claims 24–28 Narayanaswamy teaches liquefied waste plastics obtainable by thermal degradation (pyrolysis), fractionation and splitting of plastic-derived streams, hydrotreating with supported NiMo/CoMo catalysts on alumina, and downstream separation/distillation (Narayanaswamy ¶¶ [0019], [0023], [0032]). Hájeková teaches blending with paraffinic naphtha for steam-cracker feed preparation. Specifying paraffin-rich (including renewable) paraffinic materials and conventional separations constitutes an obvious selection among known alternatives. Claim 33 Narayanaswamy’s detailed hydrocarbon analyses of hydrocracked and cracked liquid products explicitly report measurable naphthene contents within liquid paraffinic streams. Akimoto further teaches that fuel oils and paraffinic fractions derived from thermal degradation of mixed waste plastics and subsequently refined (including hydrothermal and hydroprocessing treatments) characteristically contain naphthenes in minor but non-zero amounts, typically within single-digit to low-teens weight percent ranges, depending on processing severity and feed composition (Akimoto, Tables 1–4; Discussion, “Physical and Physicochemical Properties of Refined Fuel Oil”). Akimoto expressly demonstrates paraffinic fuel fractions containing naphthenes well within the claimed 0.01–15.00 wt.% range. It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to operate the integrated plastic-to-hydrocarbon process of Narayanaswamy under known hydrocracking and cracking severities so as to obtain a paraffinic material having a naphthenes content within the claimed range, as taught and exemplified by Akimoto, because naphthene formation and retention in paraffinic refinery streams is a predictable result of hydrocracking and cracking severity optimization, and the claimed range represents a result-effective variable routinely controlled in petroleum and plastic-derived hydrocarbon processing. Claims 29 and 30 are rejected under 35 U.S.C. 103 as being unpatentable over references as applied to claim 16 above, and further in view of Blackwell et al. (US 7,258,848 B1) The process Narayanaswamy of is as discussed above. Narayanaswamy teaches scrubbing acid gases from process gas streams, including liquid scrubbing approaches (Narayanaswamy ¶ [0019]). Narayanaswamy does not teach a step of washing the gaseous effluent with an acidic liquid medium. Blackwell teaches a step of removing contaminates from an acid gas by utilizing acidic liquid medium (e.g., sulfuric acid). See abstract; claim 1. It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to have modified the process of Narayanaswamy by treating the acid gas from the hydrotreating step with an liquid acid as suggested by Blackwell to remove contaminates from the acid gas. Response to Arguments Applicant argues that step (B) of claim 16 is definite because a person of ordinary skill in the art would understand that contacting the liquefied waste plastics (LWP) material with the aqueous medium produces a mixture, and that such mixture is the subject of the subsequent liquid-liquid separation. The Examiner respectfully disagrees. Claim 16 recites, in relevant part, “pre-treating the liquefied waste plastics material by contacting the liquefied waste plastics material with an aqueous medium … followed by liquid-liquid separation, to produce a pre-treated liquefied waste plastics material.” However, the claim does not explicitly identify what stream or phase is subjected to the liquid-liquid separation, nor does it specify which phase(s) resulting from such separation constitute the “pre-treated liquefied waste plastics material.” While Applicant asserts that the mixture resulting from the contacting step would be understood as the input to the liquid-liquid separation, the claim language itself does not so specify. Moreover, liquid-liquid separation inherently produces at least two liquid phases, and the claim does not indicate whether the pre-treated LWP material corresponds to the aqueous phase, the organic phase, or a portion thereof. As a result, the scope of the claim is unclear. Because the claim fails to particularly point out and distinctly claim the subject matter regarded as the invention, the rejection of claims 16–30 and 33 under 35 U.S.C. §112(b) is maintained. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to TAM M NGUYEN whose telephone number is (571)272-1452. The examiner can normally be reached Mon - Frid. 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, Prem C Singh can be reached at 571-273-6381. 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. /TAM M NGUYEN/Primary Examiner, Art Unit 1771
Read full office action

Prosecution Timeline

May 27, 2022
Application Filed
May 27, 2022
Response after Non-Final Action
Sep 20, 2025
Non-Final Rejection — §103, §112
Dec 29, 2025
Response Filed
Jan 14, 2026
Non-Final Rejection — §103, §112 (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

2-3
Expected OA Rounds
78%
Grant Probability
88%
With Interview (+10.9%)
2y 9m
Median Time to Grant
Moderate
PTA Risk
Based on 963 resolved cases by this examiner. Grant probability derived from career allow rate.

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