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
Examiner acknowledges Applicant’s response filed 06 July 2026 containing remarks and amendments to the claims.
The previous rejections have been updated as necessitated by amendments to the claims. The updated rejections follow.
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 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:
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, 4-5, 10-12, 18-20, 23, and 25-27 are rejected under 35 U.S.C. 103 as being unpatentable over Kirkwood (US 5,364,995) in view of Reed (US 5,656,150).
Regarding claims 1, 10-12, 18, and 26, Kirkwood teaches passing naphtha (a non recycle cracker feed) through convective bank of a steam cracker (see figure 4, column 10, lines 1-10). Naphtha and steam from the convection section are combined with pyrolysis oil obtained from waste plastic pyrolysis and introduced into the radiant section which is downstream of the convection inlet (see figure 4, column 10, lines 10-50) and the mixture is cracked in the steam cracker to produce ethylene, propylene, butadiene (olefin) products (column 10, lines 45-60).
Examiner notes that the polymer feed + fluid bed used to create the molten wax (liquid feed) (column 8, lines 45-60) are “a source external of the cracker furnace”. See figure 4, showing an external fluid bed reactor, and polymer feed.
Kirkwood teaches that the naphtha (non recycle cracker feed) is mixed with pyrolysis oil obtained from waste plastic pyrolysis (which Examiner considers to read on the claimed recycle content pyrolysis oil) and fed to the radiant bank of steam cracker (see figure), which reads on the claimed location of downstream of convection and upstream of radiant.
Kirkwood teaches pyrolysis of high density polyethylene at temperatures of 500°C (see example no 1 in table 1) to create feedstock to be combined with naphtha and fed to radiant section of the steam cracker. Examiner notes that the instant specification similarly teaches creation of the recycle content oil by pyrolysis of high density polyethylene [0130], [0131] at temperatures of above 325°C, above 350°C, above 375°C, above 400°C, above 425°C, above 450°C, above 475°C above 500°C [0139].
Therefore, it is expected that the Kirkwood feed obtained from pyrolysis of high density polyethylene at a temperature of 500°C would have the same or similar properties, including being liquid at 25°C and 1 atm, and introduction to the furnace, since it is formed by the same pyrolysis of high density polyethylene at the same temperature as identified in the applicant’s instant specification. Further, Kirkwood teaches that feedstock to the steam cracker is “molten wax” (see column 8, lines 45-58), which indicates liquid form of the wax.
Alternatively, it would have been obvious to the person having ordinary skill in the art that the Kirkwood feed obtained from pyrolysis of high density polyethylene at a temperature of 500°C would have the same or similar properties, including being liquid at 25°C and 1 atm and introduction, since it is formed by the same pyrolysis of high density polyethylene at the same temperature as identified in the applicant’s instant specification.
Further, Examiner notes that upon introduction to the furnace, Applicant teaches cracking reaction temperatures of 600-1000°C (see Applicant’s instant specification [0139]). Examiner notes that the reaction temperatures of the instant specification are much higher than room temperature, and the rpyoil of the instant specification would be in the vapor phase during cracking. In this regard, the products from the pyrolysis furnace are obtained in vapor phase [0145]. Examiner notes that Kirkwood similarly teaches steam cracker temperatures above 600°C, including 750-850°C (column 5, lines 20-35), which lies within the reaction temperatures discussed in the instant specification. In this regard, Examiner notes that in the instant specification and in Kirkwood, the pyoil and non recycle feed will be in the gaseous phase, since they are both run at the same temperature.
Kirkwood teaches naphtha steam cracker feed. Kirkwood does not disclose (1) ethane, propane, and/or butane feed (2) the claimed ratio of recycle to non recycle feed of at least 65 wt% non-recycle feed or the hydrocarbon mass flow rate of the combined stream is at least 5% higher than the mass flow rate of the non-recycle cracker feed stream before introduction of the pyoil stream.
Regarding (1), Reed teaches that in addition to naphtha, other conventional steam cracking feeds include ethane, propane, butane, and mixtures thereof (column 2, lines 10-26).
Therefore, it would have been obvious to the person having ordinary skill in the art to have selected a feed including the ethane, propane, or butane components alone or in mixture with the naphtha and pyrolysis oil (column 2, lines 10-26). Examiner further notes that it would have been obvious to the person having ordinary skill in the art to select the amount of each feedstock based of coking tendency, availability, and economic considerations. It is not seen where such a selection would result in any new or unexpected results.
Regarding (2), Kirkwood teaches that the steam cracker feed contains 5-50% of the steam cracker feed is the polymer derived product (recycle feed) (column 3, lines 20-32). Kirkwood teaches using mixtures of conventional naphtha steam cracker feed with the wax (recycle products) (see column 9, table ii).
Examiner notes that it would have been obvious to the person having ordinary skill in the art to have selected appropriate amounts of each feedstock, based off availability, economics, or desired product. It is not seen where such a selection would result in any new or unexpected results.
Regarding claim 4, Kirkwood teaches steam to hydrocarbon ratio of 0.2:1 to 1:1, more preferably 0.3:1 to 0.6:1 (column 5, lines 20-30). It is further expected that the same improvements in propylene yield would be achieved, since Kirkwood teaches the same exact process steps as applied to the claims above, using the same steam ratios as recited. It is not seen where Applicant has distinguished the process steps in this regard.
Regarding claim 5, Kirkwood teaches steam cracking for a residence time of 0.9 seconds (column 8, lines 45-58), which reads on the claimed range.
Regarding claim 19, Kirkwood teaches steam cracking temperatures of 750-850°C (column 5, lines 20-35).
While Kirkwood does not explicitly disclose a heating step, Examiner notes that it would have been obvious to the person having ordinary skill in the art to have provided appropriate heating steps in order to bring reactants to the reaction temperatures recited by Kirkwood.
Therefore, it would have been obvious to the person having ordinary skill in the art to have provided appropriate pre heating equipment, in order to bring the feedstocks to desired reaction temperatures. It is not seen where such an implementation to achieve desired conditions of Kirkwood would result in any new or unexpected results.
Regarding claim 20 and 23, Kirkwood teaches the steam cracker feed is in the vapor form (column 5, lines 25-35), which Examiner considers to be entirely vapor, and to read on the claimed range. Kirkwood combines steam, naphtha, and waste plastic pyrolysis oil at the crossover section of the furnace between convection and radiant section.
Regarding claim 25, the prior art teaches the same process steps applied to the same feeds at the same conditions as claimed. Therefore, it is expected that the same or similar products would result having the same or similar properties. It is not seen where Applicant has distinguished the process steps in this regard.
Regarding claim 27, Examiner considers the line connecting the fluid bed reactor to the steam cracker to be a “transfer line”. Examiner additionally notes that storage vessels are well-known in the art, and would be an obvious variation to store intermediates, prior to further treatment. The person having ordinary skill in the art may be motivated to employ a storage vessel, in the case that not all of the fluid bed effluent is intended to be used, or if the steam cracking is not performed immediately, or if the steam cracker needs to be cleaned out while the fluid bed is still operational.
Claims 2 and 13-16, are rejected under 35 U.S.C. 103 as being unpatentable over Kirkwood (US 5,364,995) in view of Reed (US 5,656,150), as applied to claim 1 above, and further in view of Buchanan (US 2007/0090020).
Regarding claims 2 and 13-15, the previous combination teaches the limitations as discussed with respect to claim 1 above. The previous combination does not explicitly disclose the location of steam introduction.
However, Buchanan teaches it is conventional to introduce steam cracker feeds into the convection section, through crossover, and into radiant [0005].
Therefore, it would have been obvious to the person having ordinary skill in the art to have selected appropriate injection points in the steam cracking furnace for each of the components in view of Buchanan teachings. It is not seen where such a modification would result in any new or unexpected results.
Regarding claims 16, Kirkwood teaches that the feed to the steam cracker is vaporized (column 5, lines 20-30).
While Kirkwood does not explicitly disclose atomization of the feedstock, Examiner notes that atomization is well known in the art to facilitate rapid and efficient vaporization and introduction of fluids into reaction zones.
Therefore, it would have been obvious to the person having ordinary skill in the art to have performed atomization as is well known in the art, to the feedstock of Kirkwood, for the benefit of facilitating the desired vaporization and efficient introduction into the reactor. It is not seen where such a modification would result in any new or unexpected results.
Claims 3 and 22 are rejected under 35 U.S.C. 103 as being unpatentable over Kirkwood (US 5,364,995) in view of Reed (US 5,656,150), as applied to claims 1 and 18 above, and further in view of Stabel (US 5,731,483) and Ward (US 2016/0362609).
Regarding claim 3, Kirkwood teaches pyrolysis of naphtha in combination with waste plastic derived pyrolysis oil.
Kirkwood does not explicitly disclose the ratio of pyoil with respect to the combined feed.
However, Stabel teaches that the waste pyrolysis oil may fully replace a conventional naphtha feed (column 1, lines 5-25). Ward teaches a similar process for steam cracking, which envisions blending plastic derived pyrolysis oil with naphtha, in order to improve the economics of the conventional naphtha steam cracker [0010].
Therefore, it would have been obvious to the person having ordinary skill in the art to have blended a conventional naphtha feed with the plastic derived pyrolysis oil of Stabel/Ward, for the benefit of improving the economic situation of conventional steam crackers, and selected appropriate amounts of each component for the benefit of obtaining the desired economic benefits.
Regarding claim 22, Kirkwood teaches steam cracking for a residence time of 0.9 seconds (column 8, lines 45-58), which reads on the claimed range.
Response to Arguments
Applicant's arguments filed 06 July 2026 have been fully considered but they are not persuasive.
Examiner considers Applicant’s arguments to be:
Kirkwood does not teach the r-pyoil in the combined stream is introduced in the crossover section as a liquid, originating from an external source.
Reed does not cure the deficiencies of Kirkwood.
There is no motivation to combine Kirkwood and Reed.
Regarding Applicant’s first argument, Kirkwood teaches combining the naphtha (non recycle feed) that has passed through convection section, with the r-pyoil stream recovered from the fluid bed pyrolysis reactor, in the crossover between the convective bank and the radiative bank (see figure 4). Kirkwood teaches molten wax (liquid pyoil feed) (column 8, lines 45-60). Examiner notes that the fluid bed + polymer feed are external of the cracking furnace (see figure 4).
Regarding Applicant’s second argument, Examiner notes that Kirkwood teaches the claim limitations regarding the pyoil from external source, as discussed in the response to Applicant’s first argument.
Regarding Applicant’s third argument, Examiner notes that Reed is analogous in that it is also drawn to steam cracking of naphtha, and provides additional options for steam cracker feedstocks including ethane, propane, butane, and mixtures thereof (column 2, lines 10-26). In this regard, the person having ordinary skill in the art would have a reasonable expectation of success in combining ethane, propane, and butane with the naphtha feeds of Kirkwood, since Reed teaches that such feeds are all known alone or in combination, for the same purpose of steam cracking.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Related US Applications: 17083590, 17083586, 17083592, 17090976, 17755342, 17595512, 17595511, 17595510, 17594370, 16881035, 17593383 – cover similar process including pyrolysis oil cracking
US Application 16881032 – is related and could result in potential double patenting rejections depending on how the claims are amended
Fernandez-Baujin (US 5,190,634) – teaches inhibition of coke formation during steam cracking
Spicer (US 2009/0050530) – previously relied upon, teaches a steam cracking furnace with multiple injection points for hydrocarbons; steam; fluids including liquid hydrocarbon, water, or steam; and additional diluents (see figure, [0003-0004], [0059-0070]). Spicer teaches that vaporized feedstock is mixed with steam and introduced into the radiant section [0003]. Spicer diluents include steam or diluent hydrocarbons [0061] introduced downstream of the inlet to the convection section [0061], see figure.
Hover (US 5,639,937) – previously relied upon, teaches a similar process for steam cracking of plastic derived pyrolysis oils. Hover teaches steam to hydrocarbon ratios of 0.1-2 (column 3, lines 60-62), which overlaps with the claimed ratio. Hover further teaches that the preferred ratio is 0.3-1.3 parts steam per part plastic waste/hydrocarbon feed (column 3, lines 30-35).
US 4,176,045 – Leftin – previously cited for teaching steam cracking pyrolysis oil
US 5,364,995 – Kirkwood teaches polymer cracking and steam racking
US 2016/0264885 – Narayanaswamy teaches integrated process for upgrading waste plastics
US 2013/0296619 – teaches steam cracking of py oil from biomass feeds alone or in combination with other hydrocarbon feedstocks.
US 2008/0207974 – teaches steam cracking hydrocarbons with water and dilution steam
US 2018/0170832 – teaches steam cracking with convection, radiant, and crossover sections
US 2009/0054716 – teaches steam cracking with multiple injection points
US 2017/0081594 – teaches steam cracking furnace with multiple injection points
US 5,713,483 – teaches feeding waste plastic derived pyrolysis products to steam cracking
US 5,523,502 – teaches flexible light olefins production in a steam cracker
US 2016/0362609 – Ward teaches feeding plastic derived products to steam cracking to replace a portion of the naphtha feed [0010]
US 5,656,150 – Reed previously cited for antifoulant introduction to a steam cracker at the crossover
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 MICHELLE STEIN whose telephone number is (571)270-1680. The examiner can normally be reached Monday-Friday 8:30 AM-5:00 PM.
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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 571-272-6381. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/MICHELLE STEIN/Primary Examiner, Art Unit 1771
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