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 amendment filed June 25th, 2026 has been entered. Claims 1-16 and 18-20 remain pending in the application. The amendment has raised other issues detailed below.
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.
Claims 1, 8-9, and 10-13 are rejected under 35 U.S.C. 103 as being unpatentable over Rowles et al. (US Patent No. 4,720,293), hereinafter Rowles in view of Gouriou et al. (US Patent No. 9,638,462), hereinafter Gouriou and Van Egmond et al. (US Patent No. 7,479,468), hereinafter Van Egmond.
Regarding claim 1, Rowles discloses a process for separating an olefin stream from a methane stream (Figure, feed gas stream 10; Col. 5, lines 3-7, With reference to the single FIGURE of the drawing, feed gas stream 10 containing ethane, methane, hydrogen, and other light gases is cooled in first heat exchanger 12, wherein a portion of the components C2+ components are condensed) comprising:
providing the olefin stream comprising C2 and/or C3 olefins (Figure, feed gas stream 10; Col. 5, lines 3-7, With reference to the single FIGURE of the drawing, feed gas stream 10 containing ethane, methane, hydrogen, and other light gases is cooled in first heat exchanger 12, wherein a portion of the components C2+ components are condensed);
cooling said olefin stream in a heat exchanger with a mixed refrigerant stream to provide a cooled olefin stream (Figure, first heat exchanger 12, mixed refrigerant vapor stream 130, condensed mixed refrigerant 134; Col. 5, lines 3-7, With reference to the single FIGURE of the drawing, feed gas stream 10 containing ethane, methane, hydrogen, and other light gases is cooled in first heat exchanger 12, wherein a portion of the components C2+ components are condensed);
passing the cooled olefin stream to a demethanizer column (Figure, first distillation column 62; Col. 5, lines 32-36, The condensed portions of feed stream 10 in C2+ lines SO and 56 arc pumped using pumps 52 and 58, respectively, warmed in first heat exchanger 12, and fed to first distillation column 62 (the demethanizer), via lines 54 and 60, respectively); and
fractionating said cooled olefin stream in the demethanizer column to provide a demethanizer column overhead vapor stream and a demethanizer column bottoms liquid stream (Figure, line 63, line 76, first distillation column 62; Col. 5, lines 36-49, In first distillation column 62, these two streams are fractionated, an overhead stream is removed via line 63, partially condensed in condenser 65 and separated in separator 64. The liquid portion separated in separator 64, in line 68, is pumped using pump 70 as reflux for column 62, via line 72. The gaseous portion separated in separator 64 is reduced in pressure and mixed with stream 24, via line 66. A portion of the bottom liquid is removed from column 62, via line 74, vaporized and returned to column 62 as reboil. The remaining bottom portion is removed via line 76, reduced in pressure, partially vaporized in heat exchanger 78 and fed to second distillation column 82 (the de-ethanizer), via line 80).
However, Rowles does not disclose the demethanizer column operating at an overhead pressure of about 344 kPa gauge (50 psig) to about 2069 kPa gauge (300 psig).
Gouriou teaches the demethanizer column operating at an overhead pressure of about 344 kPa gauge (50 psig) to about 2069 kPa gauge (300 psig) (Fig. 1, column 28; Col. 7, lines 16-21, The turbine feed fraction 70 is expanded in the first turbine 26 up to a pressure substantially equal to the operating pressure of the column 28. This pressure is below 40 bars, and in particular comprised between 10 bars and 30 bars, while advantageously being equal to approximately 24 bars). Further, it has been held In the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990) (The prior art taught carbon monoxide concentrations of “about 1-5%” while the claim was limited to “more than 5%.” The court held that “about 1-5%” allowed for concentrations slightly above 5% thus the ranges overlapped.) MPEP § 2144.05-I.
Therefore, it would have been obvious before the effective filing date of the claimed invention to modify the overhead pressure of the demethanizer column of the process of Rowles to be between about 344 kPa gauge (50 psig) to about 2069 kPa gauge (300 psig) as taught by Gouriou. One of ordinary skill in the art would have been motivated to make this modification to lower the compressor work in order to reduce overall power consumption of the process.
However, Rowles as modified does not disclose the olefin stream comprising C2 and/or C3 olefins and further comprising C4-C6 olefins; and
wherein the olefin stream comprising C2 and/or C3 olefins and further comprising C4-C6 olefins is obtained from a methanol-to-olefin process.
Van Egmond teaches the olefin stream comprising C2 and/or C3 olefins and further comprising C4-C6 olefins (Col. 8, lines 18-30, FIG. 1 shows an exemplary OTO reaction system. In the figure, an oxygenate such as methanol is directed through lines 100 to an OTO fluidized reactor 102 wherein the oxygenate is converted to light olefins and various by-products which are yielded from the fluidized reactor 102 in an olefin containing stream in line 104. The olefin-containing stream in line 104 optionally comprises methane, ethylene, ethane, propylene, propane, various oxygenate byproducts, C4+ olefins, water and hydrocarbon components. The olefin-containing stream in line 104 is directed to a quench unit or quench tower 106 wherein the olefin-containing stream in line 104 is cooled and water and other readily condensable components are condensed; Further, “C4+ olefins” at least imply the inclusion of C4-C6 olefins since it has been held in considering the disclosure of a reference, it is proper to take into account not only specific teachings of the reference but also the inferences which one skilled in the art would reasonably be expected to draw therefrom (MPEP 2144.01));
wherein the olefin stream comprising C2 and/or C3 olefins is obtained from a methanol-to-olefin process (Fig. 1; Col. 6, lines 35-41, The most preferred process is generally referred to as an oxygenate-to-olefins (OTO) reaction process. In an OTO process, typically an oxygenated feedstock, most preferably a methanol- and ethanol-containing feedstock, is converted in the presence of a molecular sieve catalyst composition into one or more olefins, preferably and predominantly, ethylene and/or propylene, referred to herein as light olefins; Col. 8, lines 18-30, FIG. 1 shows an exemplary OTO reaction system. In the figure, an oxygenate such as methanol is directed through lines 100 to an OTO fluidized reactor 102 wherein the oxygenate is converted to light olefins and various by-products which are yielded from the fluidized reactor 102 in an olefin containing stream in line 104. The olefin-containing stream in line 104 optionally comprises methane, ethylene, ethane, propylene, propane, various oxygenate byproducts, C4+ olefins, water and hydrocarbon components. The olefin-containing stream in line 104 is directed to a quench unit or quench tower 106 wherein the olefin-containing stream in line 104 is cooled and water and other readily condensable components are condensed).
Rowles as modified fails to teach the olefin stream comprising C2 and/or C3 olefins and further comprising C4-C6 olefins; and wherein the olefin stream comprising C2 and/or C3 olefins is obtained from a methanol-to-olefin process, however Van Egmond teaches that it is a known method in the art of separating olefins from methane containing streams to include the olefin stream comprising C2 and/or C3 olefins and further comprising C4-C6 olefins; and wherein the olefin stream comprising C2 and/or C3 olefins is obtained from a methanol-to-olefin process. This is strong evidence that modifying Rowles as modified as claimed would produce predictable results (i.e. separating olefins from a methanol feedstock). Accordingly, it would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to modify Rowles as modified by Van Egmond and arrive at the claimed invention since all claimed elements were known in the art and one having ordinary skill in the art could have combined the elements as claimed by known methods with no changes in their respective functions and the combination would have yielded the predictable result of separating olefins from a methanol feedstock.
Regarding claim 8, Rowles as modified discloses the process of claim 1 (see the combination of references used in the rejection of claim 1 above) further comprising:
passing said demethanizer column bottoms liquid stream to a heat exchanger to provide a heat exchanged bottoms liquid stream (Figure, line 76, heat exchanger 78; Col. 5, lines 46-49, The remaining bottom portion is removed via line 76, reduced in pressure, partially vaporized in heat exchanger 78 and fed to second distillation column 82 (the de-ethanizer), via line 80); and
passing said heat exchanged bottoms liquid stream to a deethanizer column (Figure, second distillation column 82, The remaining bottom portion is removed via line 76, reduced in pressure, partially vaporized in heat exchanger 78 and fed to second distillation column 82 (the de-ethanizer), via line 80).
However, Rowles as modified does not disclose passing said demethanizer column bottoms liquid stream to the main heat exchanger.
Gouriou teaches passing said demethanizer column bottoms liquid stream to the main heat exchanger (Fig. 1, first bottoms stream 92, first compressed bottoms stream 94, first heat exchanger 20; Col. 9, lines 1-5, The first compressed bottoms stream 94 is then injected into the first heat exchanger 20, advantageously without passing through the second heat exchanger 24, to be heated to a temperature above 0° C., and in particular equal to 11.6° C).
Therefore, it would have been obvious before the effective filing date of the claimed invention to modify the flow of the demethanizer column bottoms liquid stream of the process of Rowles as modified to be routed to the main heat exchanger as taught by Gouriou. One of ordinary skill in the art would have been motivated to make this modification to provide additional refrigeration capacity within the main heat exchanger for improved heat transfer capabilities in the main heat exchanger.
Regarding claim 9, Rowles as modified discloses the process of claim 1 (see the combination of references used in the rejection of claim 1 above).
However, Rowles as modified does not disclose wherein said olefin stream comprising C2 and/or C3 olefins and further comprising C4-C6 olefins is produced from reacting oxygenates over a SAPO catalyst.
Van Egmond teaches wherein said olefin stream comprising C2 and/or C3 olefins and further comprising C4-C6 olefins is produced from reacting oxygenates over a SAPO catalyst (Col. 5, lines 26-53, Typically, molecular sieve catalysts have been used to convert oxygenate compounds to light olefins. Ideally, the molecular sieve catalyst composition comprises an alumina or a silica-alumina catalyst composition. Silicoaluminophosphate (SAPO) molecular sieve catalysts are particularly desirable in such conversion processes, because they are highly selective in the formation of ethylene and propylene. A nonlimiting list of preferable SAPO molecular sieve catalyst compositions includes SAPO-17, SAPO-18, SAPO-34, SAPO-35, SAPO-44, the substituted forms thereof, and mixtures thereof. Preferably, the molecular sieve catalyst composition comprises a molecular sieve selected from the group consisting of: SAPO-5, SAPO-8, SAPO-11, SAPO-16, SAPO-17, SAPO-18, SAPO-20, SAPO-31, SAPO-34, SAPO-35, SAPO-36, SAPO-37, SAPO-40, SAPO-41, SAPO-42, SAPO-44, SAPO-47, SAPO-56, AEI/CHA intergrowths, metal containing forms thereof, intergrown forms thereof, and mixtures thereof. The feedstock that is directed to an OTO reaction system optionally contains one or more aliphatic-containing compounds such as alcohols, amines, carbonyl compounds for example aldehydes, ketones and carboxylic acids, ethers, halides, mercaptans, sulfides, and the like, and mixtures thereof. The aliphatic moiety of the aliphatic-containing compounds typically contains from 1 to about 50 carbon atoms, preferably from 1 to 20 carbon atoms, more preferably from 1 to 10 carbon atoms, and more preferably from 1 to 4 carbon atoms, and most preferably methanol).
Therefore, it would have been obvious before the effective filing date of the claimed invention to modify the olefin stream of the process of Rowles as modified to be produced from reacting oxygenates over a SAPO catalyst as taught by Van Egmond. One of ordinary skill in the art would have been motivated to make this modification because they are highly selective in the formation of ethylene and propylene (Van Egmond, Col. 5, lines 29-32).
Regarding claim 10, Rowles as modified discloses the process of claim 1 (see the combination of references used in the rejection of claim 1 above) further comprising passing said demethanizer column overhead vapor stream to the heat exchanger to heat exchange with said olefin stream and said refrigerant stream to provide a heat exchanged overhead vapor stream (Figure, line 63, line 66, line 26, line 30, line 32, line 34, line 36; Col. 5, lines 25-31, This warmed light gas stream, now in line 24, is mixed with the overhead stream of first distillation column 62, in line 66 to form stream 26. Stream 26 is work expanded in expander 28, returned to dephlegmator 20, via line 30, and warmed to provide additional refrigeration required to operate dephlegmator 20; Col. 5, lines 41-43, The gaseous portion separated in separator 64 is reduced in pressure and mixed with stream 24, via line 66; Col. 6, lines 29-34, The combined ethane byproduct and light gas stream, now in line 34, is heat exchanged in the demethanizer condenser 65 and in first heat exchanger 12 to recover refrigeration and then compressed in compressor 38 to recover the work produced by expander 28 before being removed from the process via line 40).
Regarding claim 11, Rowles as modified discloses the process of claim 1 (see the combination of references used in the rejection of claim 1 above) further comprising passing said demethanizer column bottoms liquid stream to a heat exchanger to provide a heat exchanged bottoms liquid stream (Figure, line 76, heat exchanger 78; Col. 5, lines 46-49, The remaining bottom portion is removed via line 76, reduced in pressure, partially vaporized in heat exchanger 78 and fed to second distillation column 82 (the de-ethanizer), via line 80).
However, Rowles as modified does not disclose passing said demethanizer column bottoms liquid stream to the main heat exchanger to heat exchange with said olefin stream and said refrigerant stream to provide a heat exchanged bottoms liquid stream.
Gouriou teaches passing said demethanizer column bottoms liquid stream to the main heat exchanger to heat exchange with said olefin stream and said refrigerant stream to provide a heat exchanged bottoms liquid stream (Fig. 1, first bottoms stream 92, first compressed bottoms stream 94, first heat exchanger 20, feed stream 16, first fraction 60, first headstream 84, second headstream 98; Col. 9, lines 1-5, The first compressed bottoms stream 94 is then injected into the first heat exchanger 20, advantageously without passing through the second heat exchanger 24, to be heated to a temperature above 0° C., and in particular equal to 11.6° C).
Therefore, it would have been obvious before the effective filing date of the claimed invention to modify the flow of the demethanizer column bottoms liquid stream of the process of Rowles as modified to be routed to the main heat exchanger as taught by Gouriou. One of ordinary skill in the art would have been motivated to make this modification to provide additional refrigeration capacity within the main heat exchanger for improved heat transfer capabilities in the main heat exchanger.
Regarding claim 12, Rowles as modified discloses the process of claim 1 (see the combination of references used in the rejection of claim 1 above) further comprising:
passing said mixed refrigerant stream to a refrigerant compressor to provide a compressed mixed refrigerant stream (Figure, compressor 132; Col. 6, lines 41-45, The condensed mixed refrigerant in line 134 is then subcooled in first heat exchanger 12, flashed to a lower pressure via valve 136 and revaporized in first heat exchanger 12 before being returned to compressor 132);
passing said compressed mixed refrigerant stream to the heat exchanger to provide said cooled olefin stream and a cooled refrigerant stream (Figure, feed stream 14, Col. 6, lines 41-45, The condensed mixed refrigerant in line 134 is then subcooled in first heat exchanger 12, flashed to a lower pressure via valve 136 and revaporized in first heat exchanger 12 before being returned to compressor 132); and
passing said cooled refrigerant stream to the refrigerant compressor (Col. 6, lines 41-45, The condensed mixed refrigerant in line 134 is then subcooled in first heat exchanger 12, flashed to a lower pressure via valve 136 and revaporized in first heat exchanger 12 before being returned to compressor 132).
Regarding claim 13, Rowles as modified discloses the process of claim 12 (see the combination of references used in the rejection of claim 12 above) further comprising:
expanding said cooled refrigerant stream to provide an expanded refrigerant stream (Figure, valve 136, Col. 6, lines 41-45, The condensed mixed refrigerant in line 134 is then subcooled in first heat exchanger 12, flashed to a lower pressure via valve 136 and revaporized in first heat exchanger 12 before being returned to compressor 132);
passing said expanded refrigerant stream to the heat exchanger to provide a heat exchanged refrigerant stream (Figure, mixed refrigerant vapor stream 130, Col. 6, lines 41-45, The condensed mixed refrigerant in line 134 is then subcooled in first heat exchanger 12, flashed to a lower pressure via valve 136 and revaporized in first heat exchanger 12 before being returned to compressor 132); and
passing said heat exchanged refrigerant stream to the refrigerant compressor (Col. 6, lines 41-45, The condensed mixed refrigerant in line 134 is then subcooled in first heat exchanger 12, flashed to a lower pressure via valve 136 and revaporized in first heat exchanger 12 before being returned to compressor 132).
Claims 2-3 and 7 are rejected under 35 U.S.C. 103 as being unpatentable over Rowles as modified by Gouriou and Van Egmond as applied to claim 1 above, and further in view of Bauer et al. (US 20150052938), hereinafter Bauer.
Regarding claim 2, Rowles as modified discloses the process of claim 1 (see the combination of references used in the rejection of claim 1 above) wherein said olefin stream is separated into a vapor olefin stream and a liquid olefin stream (Figure, separator 16, line 18, line 50, line 56; Col. 5, lines 7-21, This mixed phase feed stream is removed from first heat exchanger 12 via line 14 and fed to separator 16. The uncondensed portion of feed stream 14 is then fed to dephlegmator 20, via line 18, wherein the bulk of the remaining C.sub.2.sup.+ components is condensed. The condensed, rectified C.sub.2.sup.+ material is removed from dephlegmator 20 and returned to separator 16 via line 18. It should be noted that there is two-way flow in line 18, vapor entering dephlegmator 20 from separator 16 and liquid condensate leaving dephlegmator 20 and returning to separator 16. It should also be noted that separator 16 is constructed so as to segregate the condensates produced in first heat exchanger 12 and in dephlegmator 20, as C.sub.2.sup.+ liquid streams in lines 50 and 56 respectively).
However, Rowles as modified does not disclose wherein said olefin stream is separated into a vapor olefin stream and a liquid olefin stream which are passed to the demethanizer column separately.
Bauer teaches wherein said olefin stream is separated into a vapor olefin stream and a liquid olefin stream which are passed to the demethanizer column separately (Fig. 2, line 1, separator D1, separator D3, gas fraction 44, liquid fraction 43, Pg. 2, paragraph 38, The two fractions are subsequently fed to a further separator D3 and again separated therein into a liquid fraction 43, which is fed via expansion valve V3 to 1st removal stage T1, and a gas fraction 44, which is partially condensed in heat exchanger E2 and fed to downstream separator D1; Further, Fig. 2 of Bauer depicts separator D1 to provide a gas stream to compressor X1 and a liquid stream to valve V1 which are directed to the demethanizer column T1 along with liquid fraction 43 from separator D3).
Therefore, it would have been obvious before the effective filing date of the claimed invention to modify the process of Rowles as modified wherein said olefin stream is separated into a vapor olefin stream and a liquid olefin stream which are passed to the demethanizer column separately as taught by Bauer. One of ordinary skill in the art would have been motivated to make this modification to reduce the load on the demethanizer by introducing previously separated fractions to improve overall system efficiencies.
Regarding claim 3, Rowles as modified discloses the process of claim 2 (see the combination of references used in the rejection of claim 2 above) further comprises:
passing said vapor olefin stream to the heat exchanger (Bauer, Pg. 2, paragraph 38, The two fractions are subsequently fed to a further separator D3 and again separated therein into a liquid fraction 43, which is fed via expansion valve V3 to 1st removal stage T1, and a gas fraction 44, which is partially condensed in heat exchanger E2 and fed to downstream separator D1);
cooling said vapor olefin stream in the heat exchanger to provide a cooled vapor olefin stream (Bauer, Pg. 2, paragraph 38, The two fractions are subsequently fed to a further separator D3 and again separated therein into a liquid fraction 43, which is fed via expansion valve V3 to 1st removal stage T1, and a gas fraction 44, which is partially condensed in heat exchanger E2 and fed to downstream separator D1);
separating said cooled vapor olefin stream to provide an overhead vapor olefin stream and a bottom liquid olefin stream (Bauer, Fig. 2, line 1, separator D1, separator D3, gas fraction 44, liquid fraction 43, Pg. 2, paragraph 38, The two fractions are subsequently fed to a further separator D3 and again separated therein into a liquid fraction 43, which is fed via expansion valve V3 to 1st removal stage T1, and a gas fraction 44, which is partially condensed in heat exchanger E2 and fed to downstream separator D1; Further, Fig. 2 of Bauer depicts separator D1 to provide a gas stream to compressor X1 and a liquid stream to valve V1 which are directed to the demethanizer column T1 along with liquid fraction 43 from separator D3); and
fractionating said overhead vapor olefin, said bottom liquid olefin stream, and said liquid olefin stream in the demethanizer column (Bauer, Fig. 2, line 1, separator D1, separator D3, gas fraction 44, liquid fraction 43, Pg. 2, paragraph 38, The two fractions are subsequently fed to a further separator D3 and again separated therein into a liquid fraction 43, which is fed via expansion valve V3 to 1st removal stage T1, and a gas fraction 44, which is partially condensed in heat exchanger E2 and fed to downstream separator D1; Further, Fig. 2 of Bauer depicts separator D1 to provide a gas stream to compressor X1 and a liquid stream to valve V1 which are directed to the demethanizer column T1 along with liquid fraction 43 from separator D3). Further, the limitations of claim 3 are the result of the modification of references used in the rejection of claim 2 above.
Regarding claim 7, Rowles as modified discloses the process of claim 1 (see the combination of references used in the rejection of claim 1 above).
However, Rowles does not disclose further comprising:
taking a second side stream from the demethanizer column;
passing said second side stream to the heat exchanger to provide a heated second side stream; and
passing said heated second side stream to the demethanizer column.
Bauer teaches further comprising:
taking a second side stream from the demethanizer column (Fig. 2 of Bauer depicts a side stream b to be removed from demethanizer column T1, routed through heat exchanger E2, and returned to demethanizer column T1);
passing said second side stream to the heat exchanger to provide a heated second side stream (Fig. 2 of Bauer depicts a side stream b to be removed from demethanizer column T1, routed through heat exchanger E2, and returned to demethanizer column T1); and
passing said heated second side stream to the demethanizer column (Fig. 2 of Bauer depicts a side stream b to be removed from demethanizer column T1, routed through heat exchanger E2, and returned to demethanizer column T1).
Therefore, it would have been obvious before the effective filing date of the claimed invention to modify the process of Rowles as modified to pass a second side stream through the heat exchanger for heating before being returned to the demethanizer column as taught by Bauer. One of ordinary skill in the art would have been motivated to make this modification to provide additional refrigeration capacity within the main heat exchanger for improved heat transfer capabilities in the main heat exchanger.
Claims 4-6 are rejected under 35 U.S.C. 103 as being unpatentable over Rowles as modified by Gouriou and Van Egmond as applied to claim 1 above, and further in view of Zhang et al. (CN 110617640), hereinafter Zhang.
Regarding claim 4, Rowles as modified discloses the process of claim 1 (see the combination of references used in the rejection of claim 1 above).
However, Rowles as modified does not disclose further comprising:
taking a first side stream from the demethanizer column;
passing said first side stream to the heat exchanger to provide a heat exchanged first side stream; and
passing said heat exchanged first side stream to the demethanizer column.
Zhang teaches further comprising:
taking a first side stream from the demethanizer column (See annotated Fig. 1 of Zhang below, first side stream A);
passing said first side stream to the heat exchanger to provide a heat exchanged first side stream (Fig. 1; Pg. 2, paragraph 8-9, the T11 overhead external dry gas is cold box E13, E12, E11 provide cooling enters the turbo-expander booster end (K12), then the output to the downstream after the output compressor (K13) pressurized air cooling. step S102, part of the outer conveying dry gas enters the T11 top as top reflux after cooling throttling through the cold box E11, E12, E13. providing cold T11 side line drawing 3 stream respectively is E11, E12, E13); and
passing said heat exchanged first side stream to the demethanizer column (See annotated Fig. 1 of Zhang below, heat exchanged first side stream B is passed to the demethanizer column T11).
Therefore, it would have been obvious before the effective filing date of the claimed invention to modify the process of Rowles as modified to remove a first side stream from the demethanizer column to be passed through the first heat exchanger and returned to the demethanizer column as taught by Zhang. One of ordinary skill in the art would have been motivated to make this modification in order to provide reflux to the demethanizer column to improve the separation efficiency of the demethanizer column (Zhang, Pg. 2, paragraph 9).
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Regarding claim 5, Rowles as modified discloses the process of claim 4 (see the combination of references used in the rejection of claim 4 above) further comprising:
passing said first side stream to a reflux compressor to provide a compressed first side stream (Zhang, Fig. 1, output compressor K13; See annotated Fig. 1 of Zhang below, compressed first side stream C);
passing said compressed first side stream to the heat exchanger to provide a heat exchanged first side stream (Zhang, Fig. 1; Pg. 2, paragraph 8-9, the T11 overhead external dry gas is cold box E13, E12, E11 provide cooling enters the turbo-expander booster end (K12), then the output to the downstream after the output compressor (K13) pressurized air cooling. step S102, part of the outer conveying dry gas enters the T11 top as top reflux after cooling throttling through the cold box E11, E12, E13. providing cold T11 side line drawing 3 stream respectively is E11, E12, E13);
passing said heat exchanged first side stream to the demethanizer column (See annotated Fig. 1 of Zhang below, heat exchanged first side stream B is passed to the demethanizer column T11). Further, the limitations of claim 5 are the result of the modification of references used in the rejection of claim 4 above.
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Regarding claim 6, Rowles as modified discloses the process of claim 5 (see the combination of references used in the rejection of claim 5 above) further comprising:
passing said heat exchanged first side stream to an overhead heat exchanger to provide a cooled reflux stream (Zhang, Fig. 1, cold box E13; See annotated Fig. 1 of Zhang below, cooled reflux stream D);
expanding said cooled reflux stream to provide an expanded reflux stream (See annotated Fig. 1 of Zhang below, expanded reflux stream E; Fig. 1; Pg. 2, paragraph 8-9, the T11 overhead external dry gas is cold box E13, E12, E11 provide cooling enters the turbo-expander booster end (K12), then the output to the downstream after the output compressor (K13) pressurized air cooling. step S102, part of the outer conveying dry gas enters the T11 top as top reflux after cooling throttling through the cold box E11, E12, E13. providing cold T11 side line drawing 3 stream respectively is E11, E12, E13); and
passing said expanded reflux stream to the demethanizer column (See annotated Fig. 1 of Zhang below, expanded reflux stream E is passed to the demethanizer column T11). Further, the limitations of claim 6 are the result of the modification of references used in the rejection of claim 5 above.
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Claims 14-18 and 19-20 are rejected under 35 U.S.C. 103 as being unpatentable over Rowles et al. (US Patent No. 4,720,293), hereinafter Rowles in view of Gouriou et al. (US Patent No. 9,638,462), hereinafter Gouriou, Bauer et al. (US 20150052938), hereinafter Bauer, Zhang et al. (CN 110617640), hereinafter Zhang, and Van Egmond et al. (US Patent No. 7,479,468), hereinafter Van Egmond.
Regarding claim 14, Rowles as modified discloses a process for separating an olefin stream from a methane stream comprising (Figure, feed gas stream 10; Col. 5, lines 3-7, With reference to the single FIGURE of the drawing, feed gas stream 10 containing ethane, methane, hydrogen, and other light gases is cooled in first heat exchanger 12, wherein a portion of the components C2+ components are condensed):
providing the olefin stream comprising C2 and/or C3 olefins (Figure, feed gas stream 10; Col. 5, lines 3-7, With reference to the single FIGURE of the drawing, feed gas stream 10 containing ethane, methane, hydrogen, and other light gases is cooled in first heat exchanger 12, wherein a portion of the components C2+ components are condensed);
cooling said olefin stream in a heat exchanger with a mixed refrigerant stream to provide a cooled olefin stream (Figure, first heat exchanger 12, mixed refrigerant vapor stream 130, condensed mixed refrigerant 134; Col. 5, lines 3-7, With reference to the single FIGURE of the drawing, feed gas stream 10 containing ethane, methane, hydrogen, and other light gases is cooled in first heat exchanger 12, wherein a portion of the components C2+ components are condensed);
a demethanizer column (Figure, first distillation column 62);
fractionating in the demethanizer column to provide a demethanizer column overhead vapor stream and a demethanizer column bottoms liquid stream (Figure, line 63, line 76; Col. 5, lines 36-49, In first distillation column 62, these two streams are fractionated, an overhead stream is removed via line 63, partially condensed in condenser 65 and separated in separator 64. The liquid portion separated in separator 64, in line 68, is pumped using pump 70 as reflux for column 62, via line 72. The gaseous portion separated in separator 64 is reduced in pressure and mixed with stream 24, via line 66. A portion of the bottom liquid is removed from column 62, via line 74, vaporized and returned to column 62 as reboil. The remaining bottom portion is removed via line 76, reduced in pressure, partially vaporized in heat exchanger 78 and fed to second distillation column 82 (the de-ethanizer), via line 80); and
passing said demethanizer column overhead vapor stream to the heat exchanger to heat exchange with said olefin stream and said refrigerant stream and provide a heat exchanged overhead vapor stream (Figure, line 63, line 66, line 26, line 30, line 32, line 34, line 36; Col. 5, lines 25-31, This warmed light gas stream, now in line 24, is mixed with the overhead stream of first distillation column 62, in line 66 to form stream 26. Stream 26 is work expanded in expander 28, returned to dephlegmator 20, via line 30, and warmed to provide additional refrigeration required to operate dephlegmator 20; Col. 5, lines 41-43, The gaseous portion separated in separator 64 is reduced in pressure and mixed with stream 24, via line 66; Col. 6, lines 29-34, The combined ethane byproduct and light gas stream, now in line 34, is heat exchanged in the demethanizer condenser 65 and in first heat exchanger 12 to recover refrigeration and then compressed in compressor 38 to recover the work produced by expander 28 before being removed from the process via line 40), and
passing said demethanizer column bottoms liquid stream to a heat exchanger to provide a heat exchanged bottoms liquid stream (Figure, line 76, heat exchanger 78; Col. 5, lines 46-49, The remaining bottom portion is removed via line 76, reduced in pressure, partially vaporized in heat exchanger 78 and fed to second distillation column 82 (the de-ethanizer), via line 80).
However, Rowles does not disclose the demethanizer column operating at an overhead pressure of about 344 kPa gauge (50 psig) to about 2069 kPa gauge (300 psig) and passing said demethanizer column bottoms liquid stream to the heat exchanger to heat exchange with said olefin stream and said refrigerant stream and provide a heat exchanged bottoms liquid stream.
Gouriou teaches the demethanizer column operating at an overhead pressure of about 344 kPa gauge (50 psig) to about 2069 kPa gauge (300 psig) (Fig. 1, column 28; Col. 7, lines 16-21, The turbine feed fraction 70 is expanded in the first turbine 26 up to a pressure substantially equal to the operating pressure of the column 28. This pressure is below 40 bars, and in particular comprised between 10 bars and 30 bars, while advantageously being equal to approximately 24 bars; Further, it has been held In the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990) (The prior art taught carbon monoxide concentrations of “about 1-5%” while the claim was limited to “more than 5%.” The court held that “about 1-5%” allowed for concentrations slightly above 5% thus the ranges overlapped.) MPEP § 2144.05-I.) and passing said demethanizer column bottoms liquid stream to the heat exchanger to heat exchange with said olefin stream and said refrigerant stream and provide a heat exchanged bottoms liquid stream (Fig. 1, first bottoms stream 92, first compressed bottoms stream 94, first heat exchanger 20, feed stream 16, first fraction 60, first headstream 84, second headstream 98; Col. 9, lines 1-5, The first compressed bottoms stream 94 is then injected into the first heat exchanger 20, advantageously without passing through the second heat exchanger 24, to be heated to a temperature above 0° C., and in particular equal to 11.6° C).
Therefore, it would have been obvious before the effective filing date of the claimed invention to modify the overhead pressure of the demethanizer column of the process of Rowles to be between about 344 kPa gauge (50 psig) to about 2069 kPa gauge (300 psig) as taught by Gouriou. One of ordinary skill in the art would have been motivated to make this modification to lower the compressor work in order to reduce overall power consumption of the process. Further, it would have been obvious before the effective filing date of the claimed invention to modify the flow of the demethanizer column bottoms liquid stream of the process of Rowles as modified to be routed to the main heat exchanger as taught by Gouriou. One of ordinary skill in the art would have been motivated to make this modification to provide additional refrigeration capacity within the main heat exchanger for improved heat transfer capabilities in the main heat exchanger.
Further, Rowles as modified does not disclose passing an overhead vapor olefin stream taken from said cooled olefin stream and a liquid olefin stream taken from said cooled olefin stream to the demethanizer column; and
fractionating said overhead vapor olefin stream and said liquid olefin stream in the demethanizer column to provide the demethanizer column overhead vapor stream and the demethanizer column bottoms liquid stream.
Bauer teaches passing an overhead vapor olefin stream taken from said cooled olefin stream and a liquid olefin stream taken from said cooled olefin stream to the demethanizer column (Fig. 2, line 1, separator D1, separator D3, gas fraction 44, liquid fraction 43, Pg. 2, paragraph 38, The two fractions are subsequently fed to a further separator D3 and again separated therein into a liquid fraction 43, which is fed via expansion valve V3 to 1st removal stage T1, and a gas fraction 44, which is partially condensed in heat exchanger E2 and fed to downstream separator D1; Further, Fig. 2 of Bauer depicts separator D1 to provide a gas stream to compressor X1 and a liquid stream to valve V1 which are directed to the demethanizer column T1 along with liquid fraction 43 from separator D3); and
fractionating said overhead vapor olefin stream and said liquid olefin stream in the demethanizer column to provide the demethanizer column overhead vapor stream and the demethanizer column bottoms liquid stream (Fig. 2, heavies-depleted gas fraction 10, liquid fraction 8).
Therefore, it would have been obvious before the effective filing date of the claimed invention to modify the process of Rowles as modified wherein said olefin stream is separated into a vapor olefin stream and a liquid olefin stream which are passed to the demethanizer column separately to be fractionated into the demethanizer column overhead vapor stream and the demethanizer column bottoms liquid stream as taught by Bauer. One of ordinary skill in the art would have been motivated to make this modification to reduce the load on the demethanizer by introducing previously separated fractions to improve overall system efficiencies.
Even further, Rowles as modified does not disclose fractionating a first side stream in the demethanizer column;
passing said first side stream to a reflux compressor to provide a compressed first side stream;
passing said compressed first side stream to the heat exchanger to heat exchange with said olefin stream and said refrigerant stream to provide a heat exchanged first side stream;
passing said heat exchanged first side stream to an overhead heat exchanger to provide a cooled reflux stream; and
passing said cooled reflux stream to the demethanizer column.
Zhang teaches fractionating a first side stream in the demethanizer column (See annotated Fig. 1 of Zhang below, first side stream A; Fig. 1, demethanizer T11);
passing said first side stream to a reflux compressor to provide a compressed first side stream (Fig. 1, output compressor K13; See annotated Fig. 1 of Zhang below, compressed first side stream C; Pg. 2, paragraph 8, the T11 overhead external dry gas is cold box E13, E12, E11 provide cooling enters theturbo-expander booster end (K12), then the output to the downstream after the output compressor(K13) pressurized air cooling.);
passing said compressed first side stream to the heat exchanger to heat exchange with said olefin stream and said refrigerant stream to provide a heat exchanged first side stream (Fig. 1; Pg. 2, paragraph 8-9, the T11 overhead external dry gas is cold box E13, E12, E11 provide cooling enters the turbo-expander booster end (K12), then the output to the downstream after the output compressor (K13) pressurized air cooling. step S102, part of the outer conveying dry gas enters the T11 top as top reflux after cooling throttling through the cold box E11, E12, E13. providing cold T11 side line drawing 3 stream respectively is E11, E12, E13);
passing said heat exchanged first side stream to an overhead heat exchanger to provide a cooled reflux stream (Fig. 1, cold box E13; See annotated Fig. 1 of Zhang below, cooled reflux stream D); and
passing said cooled reflux stream to the demethanizer column (See annotated Fig. 1 of Zhang below, cooled reflux stream D is passed to the demethanizer column T11).
Therefore, it would have been obvious before the effective filing date of the claimed invention to modify the process of Rowles as modified to include fractionating a first side stream in the demethanizer column; passing said first side stream to a reflux compressor to provide a compressed first side stream; passing said compressed first side stream to the heat exchanger to heat exchange with said olefin stream and said refrigerant stream to provide a heat exchanged first side stream; passing said heat exchanged first side stream to an overhead heat exchanger to provide a cooled reflux stream; and passing said cooled reflux stream to the demethanizer column as taught by Zhang. One of ordinary skill in the art would have been motivated to make this modification in order to provide reflux to the demethanizer column to improve the separation efficiency of the demethanizer column (Zhang, Pg. 2, paragraph 9).
Moreover, Rowles as modified does not disclose the olefin stream comprising C2 and/or C3 olefins and further comprising C4-C6 olefins.
Van Egmond teaches the olefin stream comprising C2 and/or C3 olefins and further comprising C4-C6 olefins (Col. 8, lines 18-30, FIG. 1 shows an exemplary OTO reaction system. In the figure, an oxygenate such as methanol is directed through lines 100 to an OTO fluidized reactor 102 wherein the oxygenate is converted to light olefins and various by-products which are yielded from the fluidized reactor 102 in an olefin containing stream in line 104. The olefin-containing stream in line 104 optionally comprises methane, ethylene, ethane, propylene, propane, various oxygenate byproducts, C4+ olefins, water and hydrocarbon components. The olefin-containing stream in line 104 is directed to a quench unit or quench tower 106 wherein the olefin-containing stream in line 104 is cooled and water and other readily condensable components are condensed; Further, “C4+ olefins” at least imply the inclusion of C4-C6 olefins since it has been held in considering the disclosure of a reference, it is proper to take into account not only specific teachings of the reference but also the inferences which one skilled in the art would reasonably be expected to draw therefrom (MPEP 2144.01)).
Rowles as modified fails to teach the olefin stream comprising C2 and/or C3 olefins and further comprising C4-C6 olefins, however Van Egmond teaches that it is a known method in the art of separating olefins from methane containing streams to include the olefin stream comprising C2 and/or C3 olefins and further comprising C4-C6 olefins. This is strong evidence that modifying Rowles as modified as claimed would produce predictable results (i.e. separating olefins from a methanol feedstock). Accordingly, it would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to modify Rowles as modified by Van Egmond and arrive at the claimed invention since all claimed elements were known in the art and one having ordinary skill in the art could have combined the elements as claimed by known methods with no changes in their respective functions and the combination would have yielded the predictable result of separating olefins from a methanol feedstock.
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Annotated Fig. 1 of Zhang
Regarding claim 15, Rowles as modified discloses the process of claim 14 (see the combination of references used in the rejection of claim 14 above) wherein said olefin stream is separated into a vapor olefin stream and a liquid olefin stream which are passed to the demethanizer column separately (Bauer, Fig. 2, line 1, separator D1, separator D3, gas fraction 44, liquid fraction 43, Pg. 2, paragraph 38, The two fractions are subsequently fed to a further separator D3 and again separated therein into a liquid fraction 43, which is fed via expansion valve V3 to 1st removal stage T1, and a gas fraction 44, which is partially condensed in heat exchanger E2 and fed to downstream separator D1; Further, Fig. 2 of Bauer depicts separator D1 to provide a gas stream to compressor X1 and a liquid stream to valve V1 which are directed to the demethanizer column T1 along with liquid fraction 43 from separator D3). Further, the limitations of claim 15 are the result of the modification of references used in the rejection of claim 14 above.
Regarding claim 16, Rowles as modified discloses the process of claim 14 (see the combination of references used in the rejection of claim 14 above) further comprises:
passing said vapor olefin stream to the heat exchanger (Bauer, Pg. 2, paragraph 38, The two fractions are subsequently fed to a further separator D3 and again separated therein into a liquid fraction 43, which is fed via expansion valve V3 to 1st removal stage T1, and a gas fraction 44, which is partially condensed in heat exchanger E2 and fed to downstream separator D1);
cooling said vapor olefin stream in the heat exchanger to provide a cooled vapor olefin stream (Bauer, Pg. 2, paragraph 38, The two fractions are subsequently fed to a further separator D3 and again separated therein into a liquid fraction 43, which is fed via expansion valve V3 to 1st removal stage T1, and a gas fraction 44, which is partially condensed in heat exchanger E2 and fed to downstream separator D1);
separating said cooled vapor olefin stream to provide an overhead vapor olefin stream and a bottom liquid olefin stream (Bauer, Fig. 2, line 1, separator D1, separator D3, gas fraction 44, liquid fraction 43, Pg. 2, paragraph 38, The two fractions are subsequently fed to a further separator D3 and again separated therein into a liquid fraction 43, which is fed via expansion valve V3 to 1st removal stage T1, and a gas fraction 44, which is partially condensed in heat exchanger E2 and fed to downstream separator D1; Further, Fig. 2 of Bauer depicts separator D1 to provide a gas stream to compressor X1 and a liquid stream to valve V1 which are directed to the demethanizer column T1 along with liquid fraction 43 from separator D3); and
passing said overhead vapor olefin, said bottom liquid olefin stream, and said liquid olefin stream to the demethanizer column (Bauer, Fig. 2, line 1, separator D1, separator D3, gas fraction 44, liquid fraction 43, Pg. 2, paragraph 38, The two fractions are subsequently fed to a further separator D3 and again separated therein into a liquid fraction 43, which is fed via expansion valve V3 to 1st removal stage T1, and a gas fraction 44, which is partially condensed in heat exchanger E2 and fed to downstream separator D1; Further, Fig. 2 of Bauer depicts separator D1 to provide a gas stream to compressor X1 and a liquid stream to valve V1 which are directed to the demethanizer column T1 along with liquid fraction 43 from separator D3). Further, the limitations of claim 16 are the result of the modification of references used in the rejection of claim 15 above.
Regarding claim 18, Rowles as modified discloses the process of claim 14 (see the combination of references used in the rejection of claim 14 above) wherein the step of passing said demethanizer column bottoms liquid stream to the heat exchanger comprises:
taking a second side stream and said demethanizer column bottoms liquid stream from the demethanizer column (Fig. 2 of Bauer depicts a side stream b to be removed from demethanizer column T1, routed through heat exchanger E2, and returned to demethanizer column T1; Rowles, Figure, line 76, heat exchanger 78; Col. 5, lines 46-49, The remaining bottom portion is removed via line 76, reduced in pressure, partially vaporized in heat exchanger 78 and fed to second distillation column 82 (the de-ethanizer), via line 80);
passing said second side stream and said demethanizer column bottoms liquid stream to the heat exchanger to provide a heated side stream and a heat exchanged bottoms liquid stream (Fig. 2 of Bauer depicts a side stream b to be removed from demethanizer column T1, routed through heat exchanger E2, and returned to demethanizer column T1; Fig. 1, first bottoms stream 92, first compressed bottoms stream 94, first heat exchanger 20, feed stream 16, first fraction 60, first headstream 84, second headstream 98; Gouriou, Col. 9, lines 1-5, The first compressed bottoms stream 94 is then injected into the first heat exchanger 20, advantageously without passing through the second heat exchanger 24, to be heated to a temperature above 0° C., and in particular equal to 11.6° C);
passing said heated side stream to the demethanizer column (Fig. 2 of Bauer depicts a side stream b to be removed from demethanizer column T1, routed through heat exchanger E2, and returned to demethanizer column T1); and
passing the heat exchanged bottoms liquid stream to a deethanizer column (Rowles, Figure, second distillation column 82, The remaining bottom portion is removed via line 76, reduced in pressure, partially vaporized in heat exchanger 78 and fed to second distillation column 82 (the de-ethanizer), via line 80). Further, the limitations of claim 18 are the result of the modification of references used in the rejection of claim 14 above.
Regarding claim 19, Rowles as modified discloses the process of claim 18 (see the combination of references used in the rejection of claim 18 above) wherein the deethanizer column is in downstream fluid communication with the demethanizer column (Rowles, Figure, second distillation column 82, The remaining bottom portion is removed via line 76, reduced in pressure, partially vaporized in heat exchanger 78 and fed to second distillation column 82 (the de-ethanizer), via line 80).
Regarding claim 20, Rowles as modified discloses the process of claim 14 (see the combination of references used in the rejection of claim 14 above).
However, Rowles as modified does not disclose wherein said olefin stream comprising C2 and/or C3 olefins and further comprising C4-C6 olefins is produced from reacting oxygenates over a SAPO catalyst.
Van Egmond teaches wherein said olefin stream comprising C2 and/or C3 olefins and further comprising C4-C6 olefins is produced from reacting oxygenates over a SAPO catalyst (Col. 5, lines 26-53, Typically, molecular sieve catalysts have been used to convert oxygenate compounds to light olefins. Ideally, the molecular sieve catalyst composition comprises an alumina or a silica-alumina catalyst composition. Silicoaluminophosphate (SAPO) molecular sieve catalysts are particularly desirable in such conversion processes, because they are highly selective in the formation of ethylene and propylene. A nonlimiting list of preferable SAPO molecular sieve catalyst compositions includes SAPO-17, SAPO-18, SAPO-34, SAPO-35, SAPO-44, the substituted forms thereof, and mixtures thereof. Preferably, the molecular sieve catalyst composition comprises a molecular sieve selected from the group consisting of: SAPO-5, SAPO-8, SAPO-11, SAPO-16, SAPO-17, SAPO-18, SAPO-20, SAPO-31, SAPO-34, SAPO-35, SAPO-36, SAPO-37, SAPO-40, SAPO-41, SAPO-42, SAPO-44, SAPO-47, SAPO-56, AEI/CHA intergrowths, metal containing forms thereof, intergrown forms thereof, and mixtures thereof. The feedstock that is directed to an OTO reaction system optionally contains one or more aliphatic-containing compounds such as alcohols, amines, carbonyl compounds for example aldehydes, ketones and carboxylic acids, ethers, halides, mercaptans, sulfides, and the like, and mixtures thereof. The aliphatic moiety of the aliphatic-containing compounds typically contains from 1 to about 50 carbon atoms, preferably from 1 to 20 carbon atoms, more preferably from 1 to 10 carbon atoms, and more preferably from 1 to 4 carbon atoms, and most preferably methanol).
Therefore, it would have been obvious before the effective filing date of the claimed invention to modify the olefin stream of the process of Rowles as modified to be produced from reacting oxygenates over a SAPO catalyst as taught by Van Egmond. One of ordinary skill in the art would have been motivated to make this modification because they are highly selective in the formation of ethylene and propylene (Van Egmond, Col. 5, lines 29-32).
Response to Arguments
Applicant's arguments filed June 25th, 2026 have been fully considered but they are not persuasive.
Applicant argues on Pg. 8-9 (as numbered by Applicant) of the Remarks, “On the hand, the claimed process entails an MTO-derived olefin stream that is inherently enriched in C2 and C3 olefins and further includes C4-C6 olefins. Accordingly, the claimed olefin stream contains a comparatively lower concentration of light ends and a higher concentration of heavier components. Therefore, the operating conditions and refrigeration integration of Rowles are not suited for, nor directed to, MTO-derived feeds… Office Action, Page 7. Applicant respectfully disagrees with the Examiner's contention and submits that if an olefin stream obtained from a MTO process is fed to the process disclosed in Rowles, the separation of the olefin stream from the methane or light gases would be ineffective with increased olefin yield loss. While the MTO feed is composed of light gases and C2/C3/C4+ olefins, the concentration of light ends, notably C1, nitrogen, hydrogen, and carbon monoxide, is much lower compared to the cracked gas or off gas feed referenced in Rowles. When MTO feed is fed to Rowles, the flash separator drum separates the light gases from the feed. Since the concentration of light ends is much lower in MTO than Rowles, the flash vapor rate from the separator drum that feeds the dephlegmator/condenser 20 and light gas expander is greatly reduced. This flash vapor is utilized as the main chilling stream for the overhead demethanizer column condenser and dephlegmator/condenser 20. Since there is a notable reduction in flash vapor for an MTO olefin feed stream, the available refrigeration duty for condensing and cooling the demethanizer overhead would be limited, reducing the available reflux for the demethanizer leading to increased C2 olefin losses in the demethanizer net overhead and poor column separation. In conclusion, substituting the teachings of Van Egmond into Rowles' s process would thwart the objective of Rowles's process which uses a feed stream comprising majority of light ends. In this regard, MPEP 2143 teaches that "If the proposed modification or combination of the prior art would change the principle of operation of the prior art invention being modified, then the teachings of the references are not sufficient to render the claims prima facie obvious." The secondary references would not suggest utilizing a heavier feed in Rowles have C4-C6 olefins and using it in a process that is suited for feed with lighter olefins. Therefore, one of ordinary skill in the art would not utilize the MTO feed of Van Egmond in the process of Rowles. Therefore, Rowles would not be modified to meet claim 1.”
However, this argument is not persuasive as the test for obviousness is not whether the features of a secondary reference may be bodily incorporated into the structure of the primary reference; nor is it that the claimed invention must be expressly suggested in any one or all of the references. Rather, the test is what the combined teachings of the references would have suggested to those of ordinary skill in the art. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981). Specifically, the teachings of Van Egmond suggest to a PHOSITA that a MTO feed stream containing C2-C4+ olefins can be cryogenically separated to create an olefin stream and a methane stream (Van Egmond, Col. 8, lines 18-30 and 53-64, FIG. 1 shows an exemplary OTO reaction system. In the figure, an oxygenate such as methanol is directed through lines 100 to an OTO fluidized reactor 102 wherein the oxygenate is converted to light olefins and various by-products which are yielded from the fluidized reactor 102 in an olefin containing stream in line 104. The olefin-containing stream in line 104 optionally comprises methane, ethylene, ethane, propylene, propane, various oxygenate byproducts, C4+ olefins, water and hydrocarbon components. The olefin-containing stream in line 104 is directed to a quench unit or quench tower 106 wherein the olefin-containing stream in line 104 is cooled and water and other readily condensable components are condensed… The separation system 126 separates the components contained in the overhead line 124. Thus, separation system 126 forms a light ends stream 127, optionally comprising methane, hydrogen and/ or carbon monoxide; an ethylene-containing stream 128 comprising mostly ethylene; an ethane-containing stream 129 comprising mostly ethane; a propylene containing stream 130 comprising mostly propylene; a propane-containing stream 131 comprising mostly propane; and one or more byproduct streams, shown as line 132, comprising one or more of the oxygenate byproducts, provided above, heavy olefins, heavy paraffins, and/or absorption mediums utilized in the separation process). Further, the teachings of Van Egmond do not provide specific concentrations of light ends that would therefore not suggest to a PHOSITA that the feed stream could not be used in the system of Rowels. See the rejection of claim 1 above.
Applicant argues on Pg. 10 (as numbered by Applicant) of the Remarks, “Bauer relates to a process for removing heavies and lights from a hydrocarbon-rich feed fraction, preferably from natural gas. Bauer does not disclose withdrawing a side stream from a demethanizer and compressing it to form reflux. Instead, Bauer generates reflux for the second removal stage (T2) via an open-loop refrigeration cycle using refrigerant streams, not column side streams. Applicant submits that a person of ordinary skill in the art would not have been motivated to modify Rowles in view of Bauer. Rowles relies on a feed stream containing relatively high methane content, while Bauer is directed to natural gas separation and addresses C2 hydrocarbons rather than C2 olefins. Bauer does not teach or suggest that its process is suitable for handling C2 olefins. Moreover, natural gas feed stream of Bauer will have higher amounts of light ends like Rowles and since the MTO process has a low concentration of light ends, a person of ordinary skill in the art would not use a natural gas separation process to treat MTO feed.”
However, this argument is not persuasive as Zhang, not Bauer is relied upon to disclose fractionating a first side stream in the demethanizer column; passing said first side stream to a reflux compressor to provide a compressed first side stream; passing said compressed first side stream to the heat exchanger to heat exchange with said olefin stream and said refrigerant stream to provide a heat exchanged first side stream; passing said heat exchanged first side stream to an overhead heat exchanger to provide a cooled reflux stream; and passing said cooled reflux stream to the demethanizer column (Zhang, Fig. 1; Pg. 2, paragraph 8-9, the T11 overhead external dry gas is cold box E13, E12, E11 provide cooling enters the turbo-expander booster end (K12), then the output to the downstream after the output compressor (K13) pressurized air cooling. step S102, part of the outer conveying dry gas enters the T11 top as top reflux after cooling throttling through the cold box E11, E12, E13. providing cold T11 side line drawing 3 stream respectively is E11, E12, E13). Further, in response to applicant's argument that Bauer is nonanalogous art, it has been held that a prior art reference must either be in the field of the inventor’s endeavor or, if not, then be reasonably pertinent to the particular problem with which the inventor was concerned, in order to be relied upon as a basis for rejection of the claimed invention. See In re Oetiker, 977 F.2d 1443, 24 USPQ2d 1443 (Fed. Cir. 1992). In this case, Bauer is analogous as it relates to a process for separating a feed stream entering a demethanizer column of a cryogenic separation process that generates a methane stream (Bauer, Fig. 2, line 1, separator D1, separator D3, gas fraction 44, liquid fraction 43, Pg. 2, paragraph 38, The two fractions are subsequently fed to a further separator D3 and again separated therein into a liquid fraction 43, which is fed via expansion valve V3 to 1st removal stage T1, and a gas fraction 44, which is partially condensed in heat exchanger E2 and fed to downstream separator D1). See the rejection of claim 14 above.
Applicant argues on Pg. 10 (as numbered by Applicant) of the Remarks, “Gouriou fails to disclose or suggest the claimed reflux compressor configuration. Gouriou is directed to energy recovery and feed conditioning using expansion turbines and heat integration but does not describe compressing a demethanizer side stream to generate reflux, nor the downstream routing through both a primary heat exchanger and a dedicated overhead heat exchanger.”
However, this argument is not persuasive as Zhang, not Gouriou, is relied upon disclose the claimed reflux compressor configuration (Zhang, Pg. 2, paragraph 8-9, the T11 overhead external dry gas is cold box E13, E12, E11 provide cooling enters the turbo-expander booster end (K12), then the output to the downstream after the output compressor (K13) pressurized air cooling. step S102, part of the outer conveying dry gas enters the T11 top as top reflux after cooling throttling through the cold box E11, E12, E13. providing cold T11 side line drawing 3 stream respectively is E11, E12, E13). See the rejection of claim 1 above.
Applicant argues on Pg. 10-11 (as numbered by Applicant) of the Remarks, “The Office Action relies on Zhang for the teachings related to side stream handling and reflux generation. However, Zhang does not disclose the claimed configuration. Zhang teaches routing process streams through multiple cold boxes (El 1, El 2, El3) for cooling and subsequently throttling the streams to generate reflux to the demethanizer column. The reflux generation in Zhang is based on cooling followed by pressure reduction (i.e., throttling), not on compression of a side stream followed by staged heat exchange.”
However, this argument is not persuasive as Zhang explicitly discloses sending the side stream A (see annotated Fig. 1 of Zhang) to compressor K13 and through an overhead heat exchanger and the main heat exchanger to provide a cooled reflux stream to the demethanizer column (See annotated Fig. 1 of Zhang; Pg. 2, paragraph 8-9, the T11 overhead external dry gas is cold box E13, E12, E11 provide cooling enters the turbo-expander booster end (K12), then the output to the downstream after the output compressor (K13) pressurized air cooling. step S102, part of the outer conveying dry gas enters the T11 top as top reflux after cooling throttling through the cold box E11, E12, E13. providing cold T11 side line drawing 3 stream respectively is E11, E12, E13). See the rejection of claim 14 above.
In response to applicant's argument that “The cited references are based on fundamentally different design approaches; i.e., Rowles uses integrated refrigeration with expanders and mixed refrigerants, Bauer uses open-loop refrigeration cycles to generate reflux, and Zhang relies on cold-box cooling followed by throttling. These systems are not interchangeable and are designed around different thermodynamic frameworks. The proposed modification of replacing the reflux system of Rowles with a compressed side-stream reflux loop incorporating both a primary heat exchanger and an overhead heat exchanger requires significant structural redesign and is not suggested by any reference”, the test for obviousness is not whether the features of a secondary reference may be bodily incorporated into the structure of the primary reference; nor is it that the claimed invention must be expressly suggested in any one or all of the references. Rather, the test is what the combined teachings of the references would have suggested to those of ordinary skill in the art. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981).
Applicant argues on Pg. 11 (as numbered by Applicant) of the Remarks, “Moreover, the Examiner's rationale that the combination would "improve separation efficiency" is insufficient to support obviousness. The cited references provide no guidance or suggestion that such a specific and integrated reflux architecture would be beneficial or even feasible within their respective systems.”
However, this argument is not persuasive since it has been held the rationale to modify or combine the prior art does not have to be expressly stated in the prior art; the rationale may be expressly or impliedly contained in the prior art or it may be reasoned from knowledge generally available to one of ordinary skill in the art, established scientific principles, or legal precedent established by prior case law (MPEP 2144, Section I).
In response to applicant's argument that “Applicant further submits that the claimed process achieves coordinated heat integration by routing multiple streams namely, the demethanizer overhead vapor stream, bottoms liquid stream, and compressed side stream through a common heat exchanger prior to further cooling in an overhead heat exchanger. This arrangement enables improved thermal integration and reduced energy consumption. In contrast, the cited references rely on separate and distributed heat exchange systems or distinct refrigeration loops, and do not disclose or suggest such an integrated configuration. The claimed architecture therefore provides a technical advantage that is neither taught nor suggested by the cited arts”, the fact that the inventor has recognized another advantage which would flow naturally from following the suggestion of the prior art cannot be the basis for patentability when the differences would otherwise be obvious. See Ex parte Obiaya, 227 USPQ 58, 60 (Bd. Pat. App. & Inter. 1985).
The rejections of independent claims 1 and 14 are maintained. The rejections of dependent claims 2-13, 15-16 and 18-20 are also maintained for at least the reasons described herein.
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 DEVON T MOORE whose telephone number is 571-272-6555. The examiner can normally be reached M-F, 7:30-5.
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Frantz Jules can be reached at 571-272-6681. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
/DEVON MOORE/Examiner, Art Unit 3763 August 17th, 2026
/FRANTZ F JULES/Supervisory Patent Examiner, Art Unit 3763
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