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The rejection of claims under 35 USC § 103 over 1-20 is withdrawn by the examiner in view of the amendment filed on 8/21/2026.
Since a new Final Office Action follows, Applicants’ 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 1, 3-10, 12-13, 15-16, and 18-20 are rejected under 35 U.S.C. 103 as being unpatentable over Stabel et al. (US 5,731,483; “Stabel”) in view of Bitting et al. (WO 2021/163106 A1; “Bitting”), Green (US 3,829,521; “Green”), and Oud et al. (WO 2021/205011 A1; corresponding to US 2023/0135324 A1; “Oud”).
Regarding claims 1 and 10, Stabel teaches recycling waste plastic to produce high-value feed materials for a steam cracker, which are converted into cracked products including ethylene, propylene, C4 products, and pyrolysis gasoline (Stabel, col. 2, lines 3-22). Stabel teaches melting plastic waste, thermally converting the polymers, separating a distillate fraction, and feeding the fraction to a steam cracker (col. 2, lines 21-48).
Stabel further teaches converting the polymers without addition of hydrogen, vapor, catalysts, solvents, or diluents into products capable of being vaporized and conventionally cracked in a steam cracker (col. 5, lines 9-23), and feeding both an organic liquid fraction and an HCl-free gas fraction to the steam cracker (col. 5, lines 42-65). Thus, Stabel teaches the waste-plastic/steam-cracking framework and feeding a non-hydroprocessed feed to the cracker.
Stabel does not teach feeding the pyrolysis gas to the cracker facility downstream of the cracker furnace.
Bitting teaches pyrolyzing recycled waste material to produce recycle-content pyrolysis gas and introducing at least a portion of the pyrolysis gas into a cracker facility at a location downstream of an outlet of the cracker furnace (Bitting, ¶¶ [0013], [0017]).
It would have been obvious to one having ordinary skill in the art, before the effective filing date of the claimed invention to introduce the plastic-derived pyrolysis gas of Stabel into the cracker facility downstream of the cracker furnace, as taught by Bitting, because such routing permits integration of the pyrolysis-derived gas into the downstream cracker separation system without requiring passage of that gas through the cracker furnace.
Stabel and Bitting do not teach recovering CO₂ from the pyrolysis gas.
Green teaches treating pyrolysis cracked gas in an olefins plant to remove acid gases including CO₂ by contacting the cracked gas with an aqueous amine solution (Green, col. 1, lines 9-46). Green further teaches that the acid-gas absorber produces pyrolysis cracked gas substantially freed of CO₂ and H₂S and sends the purified cracked gas to downstream equipment for separation into ethylene, propylene, and/or other products (col. 5, lines. 1-25).
It would have been obvious to one having ordinary skill in the art, before the effective filing date of the claimed invention to subject the pyrolysis gas of the modified Stabel/Bitting process to the CO₂ removal/recovery treatment taught by Green because Green teaches removal of CO₂ from pyrolysis cracked gas prior to downstream recovery of desired olefin products.
The combination of Stabel, Bitting, and Green does not expressly teach the claimed quantitative reduction in GWP.
Oud teaches an ultra-low-emission ethylene plant and expressly identifies improving energy efficiency and reducing greenhouse-gas emissions as objectives of an ethylene-production process (Oud, ¶¶ [0003]–[0007]). In particular, Oud teaches that reducing fuel consumption reduces CO₂ emissions (¶¶ [0003]–[0004]) and expressly seeks further reduction of specific CO₂ emissions (¶ [0037]). Oud teaches that, compared with a conventional ethylene plant, specific CO₂ emissions per tonne of ethylene produced can be reduced by at least about 30% (¶ [0038]).
It would have been obvious to one having ordinary skill in the art, before the effective filing date of the claimed invention to operate and optimize the modified Stabel/Bitting/Green process to reduce specific CO₂ emissions/GWP attributable to the produced HVCP, as taught by Oud, including by at least 0.1 kg CO₂/kg HVCP, because Oud expressly recognizes specific CO₂ emissions per quantity of ethylene product as a process-performance parameter to be reduced and teaches substantial reductions thereof. The particular degree of CO₂ recovery, fuel consumption, and resulting specific CO₂ emissions would have been subject to routine optimization to obtain the desired reduction.
The recitation of determining GWP in accordance with ISO 14040 and ISO 14044 specifies the methodology by which the environmental performance of the otherwise obvious process is evaluated and does not distinguish the physical process from that suggested by the combined references.
Regarding claims 3 and 12, Green further teaches that an olefins-plant demethanization system produces methane-rich and hydrogen/methane-rich gas streams derived from the demethanizer overhead (Green, col. 5, line 67 through col. 6, line 13).
Green does not expressly teach using the demethanizer overhead stream as fuel. However, methane and hydrogen are combustible fuel gases. It would have been obvious to one having ordinary skill in the art, before the effective filing date of the claimed invention to use at least a portion of the methane- and/or hydrogen-containing gas derived from the demethanizer overhead as fuel in the cracker facility and/or pyrolysis facility to recover its heating value and reduce consumption of externally supplied fuel.
Oud independently reinforces this modification by teaching separation of cracked gas into an ethylene-rich product stream, hydrogen-rich fuel stream, and methane-rich fuel stream and routing hydrogen-rich and/or methane-rich fuel from the separation section to combustion equipment of the ethylene plant (Oud, ¶¶ [0009]–[0022], [0055]–[0057]).
Regarding claims 4 and 13, Stabel teaches feeding dry, comminuted plastic waste into a stirring container equipped with a heating jacket and heating the plastic to form a pumpable melt (Stabel, col. 5, lines. 4-14). Stabel further teaches passing a portion of the hot bottom product from the first separation column as a heat-transfer agent through the plastic melt and through the heating jacket of the stirring container before returning the stream to the cracker (col. 5, lines. 26-38). Stabel also generally teaches passing at least some of the first-column bottom product as a heating medium through the heating jacket of the melting container before returning it to the reactor (col. 4, lines. 55-59). Thus, Stabel teaches deriving heat from a pyrolysis-derived product stream and transferring that heat through a heat-transfer medium to the waste-plastic feedstock during heating and melting.
Regarding claim 5, Green teaches removing CO₂ from pyrolysis cracked gas by absorption in an aqueous amine solution and regenerating the amine to separate the absorbed acid gases (Green, col. 1, lines 9-46; col. 5, lines 1-25).
It would have been obvious to one having ordinary skill in the art, before the effective filing date of the claimed invention to apply Green's known CO₂ recovery treatment to the pyrolysis gas of the modified Stabel/Bitting process for the reasons set forth above.
Regarding claim 6, the modified process comprises a pyrolysis facility producing pyrolysis-derived streams that are transferred directly to a cracker facility. Although the references do not expressly require the facilities to be co-located, it would have been obvious to one having ordinary skill in the art, before the effective filing date of the claimed invention to co-locate the pyrolysis and cracker facilities to facilitate direct transfer of the pyrolysis-derived streams while reducing transportation, storage, piping, and handling requirements.
Regarding claims 7 and 15, once the skilled artisan had been motivated to co-locate the pyrolysis and cracking facilities, it would have been obvious to locate the facilities within 10 miles of one another as a practical implementation of such co-location, thereby facilitating material transfer while reducing transportation, storage, piping, and handling requirements.
Regarding claims 8 and 16, Stabel expressly teaches producing steam-cracker products including ethylene, propylene, C4 products, and pyrolysis gasoline (Stabel, col. 2, lines. 7-22). Stabel's examples further identify ethylene, butenes, toluene, and xylenes in the cracked products (Stabel, Tables 14-15, cols. 13-14). Thus, Stabel teaches at least one of the recited HVCPs.
Regarding claim 9, the combined references do not expressly disclose the claimed reduction of at least 0.1 kg CO₂/kg HVCP. However, Oud expressly teaches reducing specific CO₂ emissions per tonne of ethylene produced, including a reduction of at least about 30% relative to a conventional ethylene plant (Oud, ¶¶ [0037]–[0039]).
Thus, specific CO₂ emissions per quantity of ethylene product were recognized in the art as a parameter to be reduced.
It would have been obvious to one having ordinary skill in the art, before the effective filing date of the claimed invention to optimize the CO₂ recovery and energy consumption of the modified Stabel/Bitting/Green process to reduce specific CO₂ emissions/GWP attributable to the produced HVCP, including by at least 0.1 kg CO₂/kg HVCP, because Oud expressly teaches reducing specific CO₂ emissions per amount of ethylene product and demonstrates substantial reductions thereof.
Regarding claim 18, Stabel teaches thermally converting plastic-derived material without addition of hydrogen and feeding the resulting feed material to a steam cracker (Stabel, col. 5, lines 10-23, 43-65). Stabel further teaches recovering olefin products including ethylene and propylene from steam cracking (col. 2, lines 7-22; Tables 14-15, cols. 13-14).
Green teaches removing CO₂ from pyrolysis cracked gas and subsequently processing the CO₂-depleted cracked gas to recover ethylene, propylene, and/or other products (Green, col. 1, lines 9-46; col. 5, lines 1-25).
The references do not expressly teach recovering the olefins at a GWP of less than 1.45 kg CO₂/kg olefins.
Oud, however, expressly recognizes specific CO₂ emissions per tonne of ethylene produced as an operating/environmental performance parameter and teaches deliberately reducing that parameter. Oud teaches that its integrated low-emission ethylene plant can reduce specific CO₂ emissions per tonne of ethylene by at least about 30% relative to a conventional plant (¶¶ [0037]–[0039]). Oud also teaches using a high-efficiency cracking furnace specifically to reduce CO₂ emissions (¶¶ [0060]–[0061]).
It would have been obvious to one having ordinary skill in the art, before the effective filing date of the claimed invention to optimize the known low-emission olefin-production process, including the CO₂ removal/recovery taught by Green and the energy-efficiency measures taught by Oud, to minimize the specific CO₂ emissions attributable to the recovered olefins, including to a GWP of less than 1.45 kg CO₂/kg olefins, because Oud expressly identifies specific CO₂ emissions per quantity of ethylene produced as a parameter to be reduced and teaches substantial reductions thereof. The particular operating conditions necessary to obtain the desired specific-emission level would have been a matter of routine optimization.
The recitation that GWP is measured on the basis of fossil-fuel consumption in accordance with ISO 14040/14044 specifies the methodology for evaluating the environmental performance of the otherwise obvious olefin-production process.
Regarding claim 19, Stabel expressly teaches performing the cracking in a steam-cracking facility (Stabel, col. 2, lines 7-48; col. 5, lines 10-23).
Regarding claim 20, although the references do not expressly require the cracking facility to be co-located with a pyrolysis facility, it would have been obvious to one having ordinary skill in the art, before the effective filing date of the claimed invention to co-locate the facilities to facilitate direct transfer of pyrolysis-derived feed streams while reducing transportation, storage, piping, handling, and associated energy requirements.
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
