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 .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 6/15/2026 has been entered.
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.
Claims 61, 63 and 71-82 are rejected under 35 U.S.C. §103 as being unpatentable over Stabel et al. (US 5,731,483) in view of Tallman et al. (US 7,128,827).
Stabel teaches a process for recycling waste plastics by thermally converting plastic waste into a recycle-content pyrolysis liquid, separating a distillate fraction therefrom, and feeding the distillate directly to a conventional steam cracker to produce cracked products including ethylene, propylene, C4 mixtures, and pyrolysis gasoline. Stabel teaches that the plastic-derived feed replaces conventional steam cracker feedstocks without requiring hydrogenation or hydrotreatment, and that the feed material is derived from plastic waste and contains hydrocarbons suitable for conventional steam cracking. Stabel further teaches separating a distillate fraction at about 180-280°C, recycling heavier fractions to the pyrolysis reactor, and introducing the recovered liquid and gas fractions as feed material to the steam cracker. (Stabel, col. 1, lines 42-47; col. 2, lines 22-46, 55-75; col. 3, lines 7-28; col. 5, lines 35–64; col. 8, lines 54-61; col. 10, lines 35-40; figure 3; associated description).
Tallman teaches an integrated steam cracking process wherein a light alkane stream comprising predominantly ethane and/or propane is passed through a steam pyrolysis zone to produce an olefin-containing effluent enriched in ethylene and/or propylene. Tallman further teaches that the steam cracker feed may be supplemented with additional hydrocarbon feedstocks including naphtha, condensates, gas oils, LPG, and mixtures thereof, that the hydrocarbon feed may be liquid, vapor, or mixed liquid-vapor phase, and that multiple feed streams may be processed through the same steam cracking operation. Tallman additionally teaches recovering cracked products in a conventional olefin recovery train including a depropanizer that separates an overhead stream enriched in propane and lighter hydrocarbons from a bottoms stream comprising C4+ hydrocarbons. (Tallman, Abstract; col. 2, lines 11–47; col. 3, lines 13–46; col. 4, lines 13–37; Fig. 3).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to modify Stabel's process by employing the plastic-derived recycle-content pyrolysis liquid as one of the supplemental hydrocarbon feedstocks in Tallman's steam cracking process because Tallman expressly teaches supplementing an ethane/propane steam cracker with additional liquid hydrocarbon feedstocks, including naphthas, condensates, gas oils, LPG, and mixtures thereof, thereby increasing feedstock flexibility while maintaining conventional olefin production and recovery.
Claim 61
Stabel teaches feeding a recycle-content pyrolysis liquid obtained from waste plastic directly to a steam cracker to produce ethylene, propylene, C4 mixtures, and pyrolysis gasoline, wherein the feed is not hydrogenated or hydrotreated prior to steam cracking. Stabel's plastic-derived distillate constitutes a recycle-content pyrolysis oil comprising hydrocarbons extending from C4 materials to heavy hydrocarbons suitable for steam cracking. Tallman teaches feeding a predominantly ethane and/or propane stream to the steam pyrolysis furnace together with supplemental liquid hydrocarbon feedstocks, including mixed liquid-vapor hydrocarbon feeds, producing an olefin-containing effluent enriched in ethylene and/or propylene, and separating the cracked products using a conventional recovery train including a depropanizer. (Stabel, col. 2, lines 22–46; col. 3, lines 7–28; col. 5, lines 35–64; Tallman, col. 2, lines 11–47; col. 3, lines 13–46; col. 4, lines 13–37; Fig. 3).
Claim 63
Stabel teaches a recycle-content pyrolysis oil derived from waste plastics that is introduced directly into a steam cracker without hydrotreating or hydrogenation and that contains heavy hydrocarbons suitable as steam cracker feed. Tallman teaches co-processing a predominantly ethane and/or propane stream with supplemental liquid hydrocarbon feedstocks in the same steam cracking furnace, producing an olefin-containing effluent enriched in ethylene and/or propylene, and separating the cracked gas in a depropanizer into an overhead stream enriched in propane and lighter components and a bottoms stream comprising C4+ hydrocarbons. Since the depropanizer bottoms necessarily contain the heavier cracked products while the overhead contains propane and lighter components, the claimed process criteria regarding C4+ enrichment, butadiene recovery, boiling point reduction, and increased liquid traffic represent inherent characteristics of conventional steam-cracker depropanizer operation. (Tallman, Fig. 3; col. 2, lines 11–47; col. 3, lines 13–46; col. 4, lines 13–37).
Claims 67 and 68 are rejected under 35 U.S.C. §103 as being unpatentable over Stabel et al. in view of Tallman, and further in view of Sims et al. (US 5,990,370).
The processes of Stabel and Tallman are as discussed above with respect to claim 63. Stabel teaches cracking a recycle-content pyrolysis oil together with conventional steam-cracker feedstocks to produce an olefin-containing effluent, while Tallman teaches steam cracking predominantly propane and/or predominantly ethane feedstreams and recovering cracked products through a conventional olefin recovery train including a depropanizer.
Sims teaches quantitative steam-cracking yields for both propane-rich and ethane-rich feeds. Specifically, Table 1 discloses cracking a propane-rich feed containing 16.00 wt.% propane to produce a cracked product containing 1.94 wt.% butadiene, corresponding to a butadiene-to-propane weight ratio of approximately 0.121, well above the claimed minimum ratio of 0.005. Likewise, Table 2 discloses cracking an ethane-rich feed containing 43.08 wt.% ethane to produce 0.65 wt.% butadiene, corresponding to a butadiene-to-ethane weight ratio of approximately 0.015, likewise exceeding the claimed minimum ratio of 0.005.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to operate the steam-cracking process of Stabel as modified by Tallman under conventional cracking conditions such as those taught by Sims. Sims demonstrates that steam cracking of propane-rich feedstocks produces approximately 1.94 wt.% butadiene from a feed containing 16 wt.% propane (Table 1), corresponding to a butadiene-to-propane weight ratio of approximately 0.121, and that steam cracking of ethane-rich feedstocks produces approximately 0.65 wt.% butadiene from a feed containing 43.08 wt.% ethane (Table 2), corresponding to a butadiene-to-ethane weight ratio of approximately 0.015. Both values exceed the claimed minimum ratio of 0.005. Accordingly, selecting conventional steam-cracking conditions known in the art, as evidenced by Sims, would have predictably resulted in the claimed butadiene-to-feed ratios. Claim 71 Tallman teaches that the depropanizer bottoms stream (stream 28) comprises C4 and heavier hydrocarbons. Because the depropanizer is specifically designed to recover C4+ material in the bottoms, the claimed concentration of at least 5 wt.% and/or not more than 95 wt.% represents an obvious operating range obtainable through routine fractionation control. Claim 72 Tallman teaches that small amounts of C4+ hydrocarbons may remain in the depropanizer overhead depending upon separation efficiency and operating conditions. Selecting an overhead composition containing 0.01-10 wt.% C4+ hydrocarbons would have been an obvious optimization of depropanizer operating conditions. Claim 73 Tallman teaches that the depropanizer overhead is enriched in propane and lighter hydrocarbons. Accordingly, the claimed concentration of propane and lighter components in the overhead constitutes the expected product of conventional depropanizer operation. Claim 74 Because practical depropanizers do not achieve perfect separation, Tallman inherently leaves residual propane and lighter hydrocarbons in the bottoms stream. Selecting residual concentrations within the claimed range would have been an obvious matter of routine process optimization.
Claims 75 and 76 Tallman teaches recovering propane and lighter hydrocarbons overhead while recovering C4 and heavier hydrocarbons in the bottoms. Recovering at least 50 wt.% of the respective components in their intended product streams represents ordinary fractionation performance. Claims 77 and 78 For the same reasons, recovering not more than 50 wt.% of C4+ hydrocarbons in the overhead and not more than 50 wt.% of propane and lighter hydrocarbons in the bottoms merely expresses the complementary result of conventional depropanizer operation taught by Tallman. Claims 79 and 80 Stabel teaches steam cracking recycle pyrolysis oil to maximize production of ethylene and propylene, while Tallman likewise teaches steam cracking predominantly ethane and/or propane feeds to maximize ethylene and propylene production. Selecting an r-olefin composition comprising predominantly propylene (claim 79) or predominantly ethylene (claim 80) would have been an obvious selection depending upon the selected cracker feedstock and cracking severity. Claim 81 Stabel teaches co-processing recycle pyrolysis oil with conventional steam cracker feedstocks. Selecting the recycle pyrolysis oil to comprise 20 wt.% of the total cracker feed constitutes optimization of a known result-effective variable, namely the relative proportion of recycle pyrolysis oil and conventional feedstock, to balance furnace operability, coke formation, conversion, and olefin yield. Claim 82 Stabel teaches heavy recycle pyrolysis oils containing significant heavy hydrocarbon fractions including C15+ hydrocarbons. Selecting a recycle pyrolysis oil comprising at least 10 wt.% C15+ hydrocarbons represents an obvious selection of feed composition from the heavy pyrolysis oils taught by Stabel.
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.
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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.
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/TAM M NGUYEN/Primary Examiner, Art Unit 1771
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