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 61, 63, 68, and 71-80 under 35 USC § 103 over Ramamurthy et al. in view of Tallman et al is withdrawn by the examiner in view of the amendment filed on 3/2/2026.
A new Final Office Action is follows; therefore, applicant’s arguments will not be addressed.
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, 67, 68 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 B2)
Stabel teaches a steam cracking process in which a hydrocarbon feed is introduced into a steam cracking furnace to produce an olefin-containing effluent comprising ethylene and/or propylene as primary products (Stabel, e.g., col. 2–3; col. 6–8). Stabel further teaches that suitable feeds include a range of hydrocarbons from lighter paraffins to heavier hydrocarbon fractions such as naphtha and higher-boiling materials, which inherently comprise mixtures of hydrocarbons including C4+ and higher carbon number species (col. 3–4). Thus, Stabel teaches cracking mixed hydrocarbon streams, including heavier fractions having C8+ and C12+ hydrocarbons, in a steam cracking furnace to produce an olefin-rich effluent.
Stabel does not teach the use of a cofeed and a depropanizer as claimed.
Tallman teaches a steam pyrolysis system in which the cracker feed comprises a stream predominantly comprising ethane and/or propane (col. 2, lines 28–31), and further teaches that such feed may be supplemented with additional hydrocarbon streams including naphtha, condensates, gas oils, and mixtures thereof (col. 2, lines 47–50; col. 3, line 63 – col. 4, line 3). Tallman additionally teaches that multiple hydrocarbon feedstreams may be processed simultaneously and may be introduced in liquid, vapor, or mixed liquid-vapor phases into the same steam cracking furnace (col. 4, lines 3–6; col. 8, lines 54–61; col. 10, lines 35–40), thereby evidencing co-feeding of light hydrocarbon streams with heavier hydrocarbon streams in a single cracking furnace. Tallman further teaches a cracked-gas recovery system including a depropanizer (26) that receives a column feed stream comprising at least a portion of the olefin-containing effluent and separates it into an overhead stream enriched in propane and lighter components and a bottoms stream comprising C4 and heavier hydrocarbons (Fig. 3; col. 7–9), thereby meeting the claimed separation step.
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 Stabel by incorporating the co-feeding approach and downstream separation taught by Tallman, including co-feeding a heavier hydrocarbon stream with a stream comprising predominantly ethane or propane into a single steam cracking furnace and separating the resulting effluent using a depropanizer, in order to increase feedstock flexibility, utilize multiple hydrocarbon sources, and employ conventional olefin recovery systems. The selection of a recycle hydrocarbon stream such as a pyrolysis-derived oil as the heavier hydrocarbon component represents a predictable use of known hydrocarbon feedstocks suitable for steam cracking. Further, the claimed production of an olefin-containing effluent comprising ethylene and/or propylene is an inherent result of steam cracking of such hydrocarbon feeds, as taught by Stabel and Tallman.
The selection of a heavier hydrocarbon stream obtained from pyrolysis of waste plastics (i.e., a recycle content pyrolysis oil comprising C4 and C12+ hydrocarbons and having a C8+ content of at least 15 wt.%) represents a predictable use of known hydrocarbon feedstocks suitable for steam cracking, since such pyrolysis oils are well-known to comprise mixtures of hydrocarbons spanning light to heavy fractions and are suitable for cracking to olefins. Further, the claimed result that the olefin-containing effluent comprises a majority of ethylene and/or propylene is an inherent result of steam cracking of such hydrocarbon feeds, as taught by Stabel and Tallman.
Claims 67-68
Stabel teaches steam cracking of hydrocarbon feeds (including propane and ethane-containing feeds) to produce olefins including butadiene (col. 6–7). It is well established that steam cracking of C2–C3 hydrocarbons yields non-zero amounts of C4 species including butadiene. It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention that the ratio of butadiene to propane or ethane in the feed would inherently be greater than zero, and thus readily meet a minimal threshold such as ≥ 0.001, which represents a de minimis concentration routinely present in cracked product streams.
Claims 71–74
Tallman teaches a depropanizer column separating:
propane and lighter components overhead, and
C4 and heavier components in the bottoms.
It is well understood that such separations are not perfectly sharp, and:
heavier components (C4+) may be present in the overhead in small but non-zero amounts, and
lighter components (C3−) may be present in the bottoms in minor amounts,
depending on operating conditions (reflux ratio, tray efficiency, cut sharpness).
Therefore, the recited ranges:
≥ 5 wt.% / ≤ 95 wt.% (broad ranges), and
0.01–10 wt.% leakage ranges,
represent expected and routine compositional distributions in a conventional distillation column, and would have been obvious design/operation outcomes.
Claims 75–78 (Recovery Fractions Across Column)
Tallman’s depropanizer inherently operates to:
preferentially send lighter components overhead, and
heavier components to the bottoms.
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 column such that the majority of the target components report to their intended fraction (i.e., ≥50%), since this reflects basic separation efficiency expectations in distillation design. Such thresholds (50%) are non-critical, midpoint values representing ordinary separation performance and do not require any inventive step.
Claim 79 (Predominantly Propylene)
Stabel teaches that steam cracking produces olefins including ethylene and propylene, with product distribution depending on feed composition and cracking severity (col. 6–7).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to adjust operating conditions (e.g., severity, feed composition) to favor propylene production, as propylene is a major desired product in steam cracking. Accordingly, producing an olefin composition predominantly comprising propylene represents a routine and predictable variation of known steam cracking processes.
Claim 80
Stabel teaches steam cracking of hydrocarbon feeds (including heavier hydrocarbons derived from pyrolysis oil), wherein the primary products of steam cracking are light olefins, particularly ethylene and propylene, with ethylene typically being the dominant product under conventional steam cracking severity (see Stabel, col. 6–7; examples showing olefin distributions).
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 steam cracker under conditions (e.g., temperature, residence time, dilution steam) that favor ethylene selectivity, since maximizing ethylene yield is a well-known objective in steam cracking processes. Therefore, producing an olefin composition predominantly comprising ethylene represents a routine and expected result of conventional steam cracking operation and does not patentably distinguish over Stabel.
Claim 81
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to select an appropriate proportion of pyrolysis oil (e.g., 20 wt.%) of the total cracker feed, as this represents a result-effective variable involving routine optimization of feed ratios to balance furnace operability, heat balance, coke formation, and olefin yield in stream cracking processes. The selection of a particular proportion within a known workable range of co-fed hydrocarbon stream would have been within the level of ordinary skill in the art and does not produce a new or unexpected result.
Claim 82
Stabel teaches pyrolysis-derived hydrocarbon streams comprising a broad boiling range including heavier hydrocarbons (C12+ and higher) (col. 4, lines 52–67; col. 7–9), inherently encompassing C15+ components. Given that pyrolysis oils from mixed plastic feedstocks routinely contain significant heavy fractions (C12+, C15+, and higher), it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention that the pyrolysis oil feed would include at least 10 wt.% C15+ hydrocarbons, depending on operating severity and fractionation. Accordingly, the claimed C15+ content represents an inherent and expected compositional characteristic of conventional pyrolysis oils, or at minimum a result-effective variable (cut point / severity) subject to routine optimization.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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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