DETAILED ACTION
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
This communication is in response to the amendment and arguments filed 3/27/2026.
Claims 1-22 are pending.
Previous rejections of the claims under 35 USC 103 are withdrawn as necessitated by the amendments to the claims and a new rejection recited below.
Response to Arguments
Applicant's arguments filed 3/27/2026 have been fully considered and are persuasive in part.
Applicant’s Arguments 1-2, pages 6-8
As noted by Applicant, Bai, relied upon for converting oligomerization product into propylene in an FCC reactor, teaches oligomerizing C4 olefins into higher olefin products and recycling the higher olefin products to the reaction device. The art fails to teach recycling of C4 and C6 olefins as required by amended claim 1.
Applicant’s Argument 3, page 8
With respect to Nicholas, Applicant argues “Nicholas does not teach separating an overhead stream from the main column into a second hydrocarbon stream comprising C4 olefins and contacting the dilute ethylene stream and the second hydrocarbon stream with an olefin oligomerization catalyst as recited by claim 22. Nicholas only teaches feeding a dilute ethylene stream to the oligomerization reactor wherein the dilute ethylene stream is obtained after separation of C3+ and C2- hydrocarbons by absorption with unstabilized gasoline and light cycle oil (Paragraph [0020] of Nicholas). The feeding of dilute ethylene and C4 to the oligomerization reactor is now addressed over the newly cited art below.
Claim Objection
Claim 11, line 10 should end in a semicolon instead of a period.
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(s) 1-8 is/are rejected under 35 U.S.C. 103 as being unpatentable over Nicholas (US 2010/0249474) in view of Pechimuthu (US 2021/0269725).
With respect to claim 1, Nicholas teaches a process that converts “ethylene in dilute ethylene streams, such as an FCC dry gas stream, [by] catalytically oligomeriz[ing] to heavier hydrocarbons with a Group VIII and/or Group VIB metal on amorphous silica-alumina catalyst” (0006). Specifically, Nicholas teaches:
Processing a heavy hydrocarbon feed or raw oil in an FCC unit (0014-0015) (corresponds to contacting a hydrocarbon feed stream with a fluidized catalyst to produce a cracked product stream).
Separating the cracked product from product outlet 31 in an FCC main fractionation column 92, including separating an overhead comprising gasoline and gaseous light hydrocarbons in line 97 (0017).
Separating from overhead stream 97 a condensed light naphtha stream 101 and a second “overhead stream in line 102 contain[ing] gaseous light hydrocarbon which may comprise dilute ethylene stream” (0018). The dilute ethylene stream includes dry gas, C2, as well as C3-C4 and C5+ hydrocarbons (0019).
Contacting the dilute ethylene stream (optionally including C3-C4 and some C5+ hydrocarbons, see previous step) with an olefin oligomerization catalyst and converting ethylene in the dilute ethylene stream to an oligomerized product stream (0029; 0047).
Optionally, separating the oligomerized product stream into a raffinate stream and heavier olefins (0029; 0047), which includes C4 and C6 olefins (see e.g. table 1).
Nicholas is silent regarding contacting at least a portion of the oligomerized product stream comprising heavier olefins, including C4 and C6 olefins, with a fluidized catalyst to convert at least a portion of the oligomerized product stream to propylene.
In analogous art of producing light olefins through FCC processes, Pechimuthu teaches a method for producing light olefins and aromatics in two FCC catalyst risers (abstract; Figure 1A). In the process of Pechimuthu, a first hydrocarbon feed is catalytically cracked in a first riser at conditions to produce a stream comprising primarily C4 to C6 hydrocarbons or a stream comprising primarily C5 to C12 hydrocarbons (abstract). When a stream comprising primarily C4 to C6 hydrocarbons is produced, the C4-C6 product is separated in a main fractionator and fed to a second catalyst riser (abstract). The second riser produces primarily light olefins (C2-C3) as the main product (abstract). When C5 to C12 is the first riser main product, the second riser may be tailored to produce primarily aromatics (abstract). “The reaction conditions in the second catalyst riser are adapted such that the yield of C2 and C3 hydrocarbons from C4 and C6 hydrocarbons is 0 to 70 wt. %.” (0009)
Therefore, before the filing date of the claimed invention, it would have been obvious to one of ordinary skill in the art to modify the process of Nicholas by sending the C4-C6 olefin product stream or portion thereof to a second FCC riser as taught in Pechimuthu because both are directed to the production of propylene using FCC, Pechimuthu teaches C4-C6 olefins may be cracked in an FCC riser for primary propylene production and Nicholas seeks to maximize propylene, and the claimed elements were known in the prior art (generally, FCC to ethylene, ethylene oligomerization to C4-6 olefins of Nicholas and C4-C6 olefins to FCC conversion to propylene of Pechimuthu) and one skilled in the art could have combined the elements as claimed by known methods with no change in their respective functions (sending the product from oligomerization to a second FCC riser), and the combination yielded nothing more than predictable results to one of ordinary skill in the art (production of propylene from the C4-C6 olefin stream).
With respect to claim 2, Nicholson teaches separating the overhead into dilute ethylene stream as well as a C3-C4 olefin containing stream 132 and a stabilized gasoline. (0019-0020)
With respect to claim 3, Pechimuthu teaches sending the C4-C6 olefins to a second riser (abstract).
With respect to claim 4, Pechimuthu teaches wherein reaction conditions in first catalyst riser 101 may include a reaction temperature of 600 to 720° C, a pressure of 14 to 73 psi, WHSV of 0.5 to 30 hr−1, residence time of 1-10 s, and a catalyst-to-oil ratio (C/O ratio) of 10 to 80 (0039). Pechimuthu teaches wherein reaction conditions in second catalyst riser 103 in block 205a are adapted such that the yield of light olefins is from 0 to 70% include a reaction temperature in a range of 500 to 700° C, pressure of 14 to 73 psi, a WHSV of 5 to 30 hr−1, a residence time of 1 to 10 s, and a catalyst-to-oil ratio of 10 to 80 (0044). Pechimuthu is silent regarding the relative severity of the two reactors, though does teach wherein the first reactor is not operated with high propylene conversion and the second is operated to maximize propylene conversion. However, the art teaches the same or overlapping conditions to those claimed, as well as substantially similar feeds for maximizing production of propylene. It is expected that the same relative severity may arise.
With respect to claim 5, Nicholas teaches using an oligomerization catalyst comprising “an amorphous silica-alumina base with a Group VIII and/or VIB metal.” (abstract) Group VIII metal, preferably Nickel (0038), corresponds to a Group 8-10 metal.
With respect to claim 6, Nicholas teaches basic or alkaline metal washing of the catalyst (0049).
With respect to claim 7, Nicholas teaches that at least 40% of the ethylene in the ethylene stream is converted to heavier hydrocarbons (abstract). Nicholas fails to teach the selectivity in the range of C4-C8. However, Pechimuthu teaches wherein the C4-C6 to the second riser is favorable to the production of propylene in the second riser. Therefore, before the filing date of the claimed invention, it would have been obvious to one of ordinary skill in the art to maximize the production of C4-6 olefins fed to the second riser for the benefit of increasing propylene production as taught in Pechimuthu.
With respect to claim 8, Nicholas teaches separating from overhead stream 97 a condensed light naphtha stream 101 and a second “overhead stream in line 102 contain[ing] gaseous light hydrocarbon which may comprise dilute ethylene stream” (0018). The dilute ethylene stream includes dry gas, C2, as well as C3-C4 and C5+ hydrocarbons (0019).
Claim(s) 9-10 is/are rejected under 35 U.S.C. 103 as being unpatentable over Nicholas (US 2010/0249474) in view of Pechimuthu (US 2021/0269725) as applied to claims 1-8, further in view of Ho (US 20200063049).
With respect to claim 9, Nicholas teaches separating 162 the oligomerized product stream 160 to obtain an overhead stream 164 comprising light gases such as hydrogen, methane, ethane, unreacted olefins and light impurities, corresponding to the light raffinate stream, and a stream comprising heavier olefins 168 (0049). The light raffinate stream used as fuel, to generate steam, or otherwise disposed of (0049). Nicholas teaches wherein the stream contains unreacted olefins but is silent regarding contacting said light raffinate stream with an adsorbent in a pressure swing adsorption (PSA) unit to remove hydrogen from said light raffinate stream and provide a PSA tail gas stream comprising ethylene; and contacting said PSA tail gas stream with the olefin oligomerization catalyst.
In analogous art of ethylene oligomerization, Ho teaches subjecting an impure ethylene stream to oligomerization. First, Ho teaches a purification system 108 may be used to remove impurities from the raw product stream 106 to form an ethylene stream 110 and may include pressure swing adsorption (PSA) units (0040). The purified ethylene is then subject to oligomerization to form a raw oligomer. It would have been obvious to one of ordinary skill in the art at the time of the invention to subject the raffinate stream of Nicholas which contains unreacted ethylene and impurities to a PSA unit to remove hydrogen and impurities from unreacted ethylene for recycle to the oligomerization reactor for the benefit of recovering valuable waste products and maximizing conversion in the reactor.
With respect to claim 10, Nicholas teaches contacting said dilute ethylene with an adsorbent unit prior to isolate the ethylene prior to oligomerization (0019). PSA is a known adsorption system for separation of gases comprising ethylene as shown in Ho and would have been obvious to one of ordinary skill at the time of filing to utilize PSA, a known adsorption method, for isolating the dilute ethylene stream without obtaining new or unexpected results.
Claim(s) 11-17 and 20-22 is/are rejected under 35 U.S.C. 103 as being unpatentable over Nicholas (US 2010/0249474) in view of Shaikh (US 2021/0238485) and Pechimuthu (US 2021/0269725).
With respect to independent claims 11, 17 and 21, Nicholas teaches the limitations of claim 1. Claim 11 requires the additional steps of (i) separating an overhead stream from the main column into a second hydrocarbon stream comprising C4 olefins; and (ii) separating the oligomerized product stream to obtain a C4 olefin stream and a light raffinate stream; (iii) reacting at least a portion of the C4 olefin stream in a catalytic reaction unit to provide a converted product stream; and contacting at least a portion of the converted product stream with a fluidized catalyst to convert at least a portion of the C4 olefins to propylene.
With respect to (i), Nicholas teaches separating the overhead stream 97 from the main column into the dilute ethylene stream 122 and a second hydrocarbon stream comprising C4 olefins 132 (0018-0020).
With respect to (ii), Nicholas teaches separating 162 the oligomerized product stream 160 to obtain an overhead stream 164 comprising light gases such as hydrogen, methane, ethane, unreacted olefins and light impurities, corresponding to the light raffinate stream, and a stream comprising heavier olefins 168 (0049), which includes C4 olefins (Table 1). In the combined process, stream 168 or a portion there of corresponds to the stream which would be passed to a second riser for conversion into propylene.
With respect to (iii) reacting the C4 oligomerized olefins under reactor conditions prior to contacting the second riser and contacting the reacted effluent in an FCC riser to convert a portion of C4, Nicholas is silent.
Shaikh (US 2021/0238485) teaches an FCC process for producing propylene comprising: high-severity fluidized catalytic cracking of a hydrocarbon feed to produce at least propylene and a cracking reaction effluent comprising butenes (C4 olefins); metathesis and/or cracking the C4 olefins to produce an effluent comprising additional propylene and additional effluent; separating the effluent into fractions including ethylene, butene, and a C5+ fraction having at least pentene and hexene; and sending a portion the C5+ fraction back to the high-severity fluidized catalytic cracking unit to produce additional light olefins (0038; 0075-0078). Shaikh teaches that the metathesis feed 142 may include 2-butene, 1- butene, n-butane, and one or a plurality of ethylene, propene, isobutane, butadiene, isobutene, C5+ hydrocarbons, or combinations of these. “The metathesis reactor 140 may be operable to contact the metathesis feed 142 with one or a plurality of catalysts, such as but not limited to the metathesis catalyst, a cracking catalyst, or both.” (0065) Shaikh teaches wherein the effluent from the metathesis and/or cracking reactions may be fractionated into various fractions including combinations of ethylene, propylene, butenes, and C5+ compounds such as pentene and hexene. (0076-0078) One or more of the effluent fractions may be sent to downstream processing, including e.g. recycle of the C5+ stream the FCC reactor. (0077-0078)
Therefore, before the filing date of the claimed invention, it would have been obvious to one of ordinary skill in the art to modify the process of Nicholson by subjecting the C4 oligomerized stream of Nicholson to metathesis and/or cracking reactions to produce propylene, fractionating or separating the effluent, and then sending a portion of the reacted effluent to the second FCC riser in the combined process. Such would have been obvious because each reference is directed to increasing the overall production of propylene in an FCC process; treating the C4 product produced in Nicholson, whether directly from the main column or after oligomerization, would provide the benefit of increased production of propylene.
With respect to sending the reaction product to a riser to convert C4, Shaikh expressly teaches the C5+ stream comprising C5 and C6 may be recycled to a high severity riser to produce additional propylene and teaches sending the C4 olefin portion of the effluent to further downstream treatment.
As discussed above and applied here, Pechimuthu teaches sending an FCC C4-C6 effluent to a dedicated riser operating under conditions to maximize propylene production. Therefore, before the filing date of the claimed invention, it would have been obvious to one of ordinary skill in the art to modify the process of Nicholson in view of Shaikh by contacting at least a portion of the converted product stream including both C4 and C5+ with a fluidized catalyst in a dedicated riser because Pechimuthu teaches sending C4-C6 olefin product to a second riser under dedicated conditions allow improved overall production of propylene.
While the C4 stream of Nicholson is obtained from oligomerization of dilute C2, the stream contains the same components, originates from an FCC process and may be mixed with the FCC effluent. It would have been obvious to apply the steps Shaikh and Pechimuthu to any of the C4 olefin product streams of Nicholson, including C4 olefins separated from the FCC unit or C4 olefins produced by agglomerating C2 effluent, to achieve the same predictable production of propylene.
With respect to claims 12 and 13, Pechimuthu teaches wherein the feed is contacted with a catalyst in a first riser at first conditions and wherein the converted olefins are contacted with catalyst in a second riser at second set of conditions (Figure 1).
With respect to claim 14, Pechimuthu is silent regarding the relative severity of the two risers. However, the art teaches the same or overlapping conditions and catalysts to those claimed, as well as substantially similar feeds for maximizing production of propylene. It is expected that the same relative severity may arise. Shaikh teaches contacting the C5 stream under high severity conditions.
With respect to claim 15, Nicholas teaches using an oligomerization catalyst comprising “an amorphous silica-alumina base with a Group VIII and/or VIB metal.” (abstract) Group VIII metal, preferably Nickel (0038), corresponds to a Group 8-10 metal.
With respect to claim 16, Nicholas teaches that at least 40% of the ethylene in the ethylene stream is converted to heavier hydrocarbons (abstract). Nicholas fails to teach the selectivity in the range of C4-C8. However, Pechimuthu teaches wherein the C4-C6 to the second riser is favorable to the production of propylene in the second riser. Therefore, before the filing date of the claimed invention, it would have been obvious to one of ordinary skill in the art to maximize the production of C4-6 olefins fed to the second riser for the benefit of increasing propylene production as taught in Pechimuthu.
With respect to claim 20, Nicholas teaches wherein the dilute ethylene stream of the present invention may comprise an FCC dry gas stream comprising between about 5 and about 50 wt-% ethylene, between about 25 and about 55 wt-% methane, and between about 5 and about 45 wt-% ethane (0021), which overlaps with the claimed ranges for ethylene and methane. Nicholas further teaches the stream comprising impurities of about 1 and about 25 wt-% hydrogen and nitrogen each, water (0021). “Besides hydrogen, other impurities such as hydrogen sulfide, ammonia, carbon oxides and acetylene may also be present in the dilute ethylene stream.” (0022) The dilute stream to the oligomerization catalyst “will typically have at least one of the following impurity concentrations: about 0.1 wt-% and up to about 5.0 wt-% of carbon monoxide and/or about 0.1 wt-% and up to about 5.0 wt-% of carbon dioxide, and/or at least about 1 wppm and up to about 500 wppm hydrogen sulfide and/or at least about 1 and up to about 500 wppm ammonia, and/or at least about 5 and up to about 20 wt-% hydrogen.” (0027)
Claim(s) 11 and 18 is/are rejected under 35 U.S.C. 103 as being unpatentable over Nicholas (US 2010/0249474) in view of Pechimuthu (US 2021/0269725) and Li (US 2021/0355048).
Claim(s) 19 is/are rejected under 35 U.S.C. 103 as being unpatentable over Nicholas (US 2010/0249474) in view of Shaikh (US 2021/0238485) and Pechimuthu (US 2021/0269725) as applied to claims 11-17 and 20-22, further in view of Li (US 2021/0355048).
With respect to claims 11 and 18, Nicholas in view of Pechimuthu teach the limitations of claims 1-8 as discussed above Nicholas the FCC and oligomerization steps and Pechimuthu recycling the C4 to C6 olefins to a second FCC unit to increase propylene production) and applied equally here. The art fails to teach sending the oligomerized product to a catalytic reaction unit comprising oligomerization prior to sending a portion of the C4 effluent to the FCC unit.
Li teaches a process for upgrading through oligomerization comprising sending a feed of Cn and C2n, wherein n may be 2, to upgrade the feed to olefins comprising C3n, which includes C6. Therefore, before the filing date of the claimed invention, it would have been obvious to one of ordinary skill in the art to modify Nicholson in view of Pechimuthu by subjecting the oligomerized effluent containing C4 and C2 olefins to a second oligomerization step to increase the production of C4-C6 olefins prior to recycling to the second riser for the benefit of increasing propylene production.
With respect to claim 19, the art fails to teach contacting the second hydrocarbon stream containing C4 from the overhead with the olefin oligomerization catalyst. Li teaches a process for upgrading through oligomerization comprising sending a feed of Cn and C2n, wherein n may be 2, to upgrade the feed to olefins comprising C3n, which includes C6. Therefore, before the filing date of the claimed invention, it would have been obvious to one of ordinary skill in the art to modify Nicholson by sending the C4 from the FCC overhead with the ethylene to the oligomerization reactor as taught in Li for the benefit of increasing the volume of C4-C6 olefins produced and therefore increasing the overall production of propylene.
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 Brandi Doyle whose telephone number is (571)270-1141. The examiner can normally be reached Monday-Friday, 8:00 AM - 3:00 PM.
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/BRANDI M DOYLE/Examiner, Art Unit 1771
/PREM C SINGH/Supervisory Patent Examiner, Art Unit 1771
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