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 .
Election/Restrictions
Applicant’s election without traverse of Group I, claims 1-16, in the reply filed on 9/28/2026 is acknowledged.
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 1-8 and 11-13 are rejected under 35 U.S.C. §103 as being unpatentable over Destour et al. (US 2016/0146534 A1) in view of Stanley et al. (US 8,952,211 B2).
Claim 1: Destour teaches a process for separating carbon monoxide from an ethylene-containing stream, comprising cooling the stream using refrigerant, introducing the cooled stream into fractionation column 50, recovering an ethylene-rich liquid stream 96, and recovering overhead stream 98 containing carbon monoxide and ethylene (¶¶ [0074]–[0077], [0096]–[0100], [0110]–[0115]; Fig. 1). Destour further teaches cooling overhead stream 98 and separating it in vessel 58 into liquid fraction 102 and gaseous fraction 104 (¶¶ [0115]–[0117]).
However, Destour does not teach contacting the gaseous fraction with a hydrocarbon absorbing liquid to recover additional ethylene and produce an ethylene-depleted carbon monoxide-containing vapor stream.
Stanley teaches using a hydrocarbon absorbing liquid to absorb and recover ethylene from a gas stream containing lighter gaseous components (see the detailed description of its absorber-demethanizer system and Fig. 1).
It would have been obvious to one having ordinary skill in the art, before the effective filing date of the claimed invention, to contact the gaseous overhead fraction of Destour with a suitable hydrocarbon absorbing liquid, as taught by Stanley, to recover residual ethylene and reduce ethylene losses in the carbon monoxide-containing vapor stream.
Claim 2: Destour teaches utilizing heat exchange between an incoming ethylene-containing feed stream and reboiler 54 of fractionation column 50 (¶ [0149]; Fig. 5), thereby providing the claimed feed-to-reboiler heat integration.
Claim 3: Destour teaches recovering ethylene-rich liquid stream 96 and utilizing heat exchange between process streams to recover refrigeration duty (¶¶ [0112], [0118]–[0121]). However, Destour does not expressly teach heating the recovered liquid ethylene stream using the incoming feed before cooling that feed. It would have been obvious to one having ordinary skill in the art, before the effective filing date of the claimed invention, to provide such heat exchange to recover available refrigeration duty and reduce external cooling requirements, provided a suitable temperature difference exists.
Claim 4: Destour teaches cooling overhead stream 98 with refrigerant in condenser 56 before separating the cooled stream into liquid and gaseous portions in vessel 58 (¶¶ [0115]–[0117]; Fig. 1).
Claim 5: Destour teaches recovering liquid ethylene stream 96 from fractionation column 50 and employing refrigeration and process heat exchange (¶¶ [0074]–[0077], [0112], [0118]–[0121]). However, Destour does not expressly teach subcooling refrigerant by heat exchange with a portion of liquid ethylene stream 96.
It would have been obvious to one having ordinary skill in the art, before the effective filing date of the claimed invention, to provide an additional heat exchanger for subcooling a suitable refrigerant using available refrigeration capacity of liquid ethylene stream 96, thereby conserving energy and reducing external refrigeration requirements.
Claim 6: Destour teaches recovering gaseous fraction 104 from overhead separator 58 and using that cold gaseous fraction for heat recovery in exchanger 34 (¶¶ [0115]–[0121]).
However, Destour does not expressly teach subcooling refrigerant using gaseous fraction 104.
It would have been obvious to one having ordinary skill in the art, before the effective filing date of the claimed invention, to provide an additional heat exchanger for subcooling a suitable refrigerant by heat exchange with gaseous fraction 104, thereby recovering refrigeration duty, conserving energy, and reducing external refrigeration requirements.
Claim 7: Stanley teaches using a hydrocarbon absorbing liquid to recover ethylene from a gas stream (see its absorber-demethanizer disclosure and Fig. 1). Thus, the absorbing liquid of the modified Destour process comprises a hydrocarbon.
Claim 8: Stanley teaches utilizing a hydrocarbon absorbing liquid for recovering ethylene. However, Stanley does not expressly teach that the hydrocarbon comprises an oligomerized effluent. The claimed oligomerized effluent is not limited to a particular hydrocarbon composition or concentration of oligomerization products.
It would have been obvious to one having ordinary skill in the art, before the effective filing date of the claimed invention, to utilize a suitable oligomerization-derived hydrocarbon stream as the absorbing liquid in the modified process of Destour, since such a stream would provide hydrocarbons suitable for absorbing ethylene, consistent with the hydrocarbon absorption taught by Stanley.
Claim 11: Destour teaches an ethylene-containing feed pressure of 10–40 kgf/cm² (approximately 981–3,923 kPa) and a fractionation-column operating pressure of 25–40 kgf/cm² (approximately 2,452–3,923 kPa), which overlap the claimed feed and liquid-stream pressure ranges, respectively (¶¶ [0094], [0110]).
It would have been obvious to one having ordinary skill in the art, before the effective filing date of the claimed invention, to select operating pressures within the overlapping ranges through routine optimization to achieve effective ethylene/carbon monoxide fractionation.
Claim 12: Destour teaches using a dynamic expansion turbine to expand a downstream gas fraction and recover pressure energy (¶ [0150]; Fig. 5). However, the specifically claimed ethylene-depleted vapor is obtained from the additional absorption step. It would have been obvious to one having ordinary skill in the art, before the effective filing date of the claimed invention, to provide an expansion device on a suitable pressurized ethylene-depleted vapor stream of the modified process to recover otherwise dissipated pressure energy.
Claim 13: Destour teaches recovering a cold ethylene-rich liquid stream and exchanging heat between process streams (¶¶ [0112], [0118]–[0121]). To the extent Destour does not expressly teach using the claimed liquid stream to cool the particular process stream, it would have been obvious to one having ordinary skill in the art, before the effective filing date of the claimed invention, to use an available cold liquid stream for process cooling to recover refrigeration duty and conserve energy.
Claim 9 is rejected under 35 U.S.C. §103 as being unpatentable over Destour in view of Stanley, and further in view of Lam et al. (US 5,220,097).
Claim 9: Destour in view of Stanley teaches the process of claim 1, including absorption of ethylene into a hydrocarbon absorbing liquid. However, the combination does not expressly establish reboiling the resulting enriched absorbing liquid.
Lam teaches recovering ethylene by hydrocarbon-solvent absorption and feeding the rich solvent to a solvent regeneration column, where lean solvent is recovered for recycle and an ethylene-containing hydrocarbon stream is separated (col. 11–12, claims 1 and 18; see also the description of the absorber and solvent regeneration system).
It would have been obvious to one having ordinary skill in the art, before the effective filing date of the claimed invention, to provide reboiling in the enriched-absorbent recovery system of modified Destour, consistent with Lam's solvent regeneration and reboiled absorption teachings, to recover ethylene and regenerate the absorbing liquid for reuse.
Claims 10 and 14-16 are rejected under 35 U.S.C. §103 as being unpatentable over Destour in view of Stanley, and further in view of Das et al. (US 9,701,598 B2).
Claim 10: Destour teaches recovering ethylene from a carbon monoxide-containing feed stream but does not expressly teach that the ethylene stream comprises a portion of a dehydration effluent.
Das teaches producing ethylene by dehydration of ethanol, wherein the dehydration effluent comprises ethylene, oxygenates, CO, CO₂, and other hydrocarbons, followed by cooling, compression, drying, and ethylene purification (col. 5, lines 60–65; col. 6, lines 1–30; claim 12).
It would have been obvious to one having ordinary skill in the art, before the effective filing date of the claimed invention, to utilize an ethylene-containing stream derived from ethanol dehydration, as taught by Das, as the feed to the modified process of Destour, thereby recovering purified ethylene from an alternative ethylene production source.
Claim 14: Destour teaches recovering ethylene-rich liquid stream 96 from the bottom of fractionation column 50 (¶ [0112]). However, Destour does not expressly teach further fractionating the recovered liquid stream in an oxygenate fractionation column to produce an oxygenate-containing liquid stream and an overhead stream, followed by separation of the overhead into liquid and gaseous portions, wherein the gaseous portion comprises ethylene and carbon dioxide.
Das teaches feeding the ethylene-rich liquid bottoms stream from demethanizer 1 into deethanizer 4, producing a liquid bottoms stream comprising oxygenates, ethane, and C3+ hydrocarbons and an overhead stream consisting essentially of ethylene and CO₂ (col. 8, lines 1–10; Figs. 1 and 4). Das further teaches that the deethanizer includes overhead condensation and decanting equipment analogous to that of the demethanizer, producing liquid reflux and gaseous overhead (col. 7, lines 55–65).
It would have been obvious to one having ordinary skill in the art, before the effective filing date of the claimed invention, to further fractionate the ethylene-rich liquid stream of modified Destour using the downstream deethanizer and overhead separation arrangement taught by Das, thereby removing residual oxygenated contaminants and recovering an ethylene-rich overhead stream for further purification.
Claim 15: Das teaches providing a reboiler for the deethanizer (col. 7, lines 55–65; Fig. 4). However, Das does not expressly teach reboiling the deethanizer using a hot process stream.
Destour teaches heat integration involving a fractionation-column reboiler and an incoming process stream (¶ [0149]; Fig. 5).
It would have been obvious to one having ordinary skill in the art, before the effective filing date of the claimed invention, to utilize an available hot process stream to supply reboiler duty to the oxygenate fractionation column of modified Destour, thereby recovering process heat, conserving energy, and reducing external heating requirements.
Claim 16: Das teaches condensing the deethanizer overhead at approximately -20°C to -30°C, depending on operating conditions, and providing overhead condensation and separation equipment (col. 8, lines 15–50; col. 7, lines 55–65; Fig. 4).
Destour further teaches cooling fractionation-column overhead with refrigerant before separating the cooled stream into liquid and gaseous portions in vessel 58 (¶¶ [0115]–[0117]).
It would have been obvious to one having ordinary skill in the art, before the effective filing date of the claimed invention, to employ refrigerated overhead condensation in the oxygenate fractionation column of the modified process, thereby providing the desired vapor-liquid separation and recovering condensed liquid for reflux.
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
