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 .
DETAILED ACTION
This Office action is based on the 19/179019 application originally filed April 15, 2025.
Claims 1-7, filed April 15, 2025, are pending and have been fully considered.
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) 1-7 is/are rejected under 35 U.S.C. 103 as being unpatentable over Myrick (US 2022/0203294) in view of Cook et al. (EP 0647463) hereinafter “Cook” and Henry (US 2021/0299605).
Regarding Claims 1-7
Myrick discloses in the abstract, separation of a gas mixture comprising first and second gases may be improved using three stages of gas separation membrane modules that includes the additional techniques of cooling the feed gas stream that is fed to the feed stage and using a portion of the permeate stage retentate as a sweep gas on the permeate stage.
Myrick discloses in paragraph 0053 and as best shown in FIG. 1, after any optional preliminary purification steps, the stream 1 of the gas mixture is compressed at a main compressor 5, along with any recycle gases, up to the pressure at which the first gas separation membrane module 13 is operated. Depending upon whether a cooler (such as an air cooler) is disposed downstream of the compressor, the compressed and optionally air-cooled feed gas stream 8 is typically at a pressure of 160-240 psig, at a temperature of 100-220°F.
Myrick discloses in paragraph 0049, a particular gas mixture for separation by the invention is biogas that is optionally pretreated to remove one or more contaminants. Myrick further discloses in paragraph 0050, biogas typically refers to a mixture of different gases produced from the breakdown of organic matter in the absence of oxygen in an anaerobic digestion process (i.e., digester gas). Biogas can be produced from raw materials such as agricultural waste, manure, municipal waste, plant material, sewage, green waste or food waste. Biogas typically comprises as the main components 50-70% of methane (CH4) and 20 to 50% carbon dioxide (CO2), with lower levels of other components such as N2 and O2, up to 5,000 ppm or more of hydrogen sulfide (H2S), siloxanes, up to 1,000-2,000 ppm of volatile organic compounds (VOC's), and is saturated with water.
Myrick discloses in paragraph 0054, the compressed feed gas stream 7 is cooled at a heat exchanger 9 (i.e., a chiller). At the heat exchanger 9, heat from the higher temperature feed gas stream 7 is transferred to lower temperature heat transfer fluid. The heat transfer fluid is typically a mixture of glycol and water but may be any heat transfer fluid suitable for cooling the compressed feed gas stream 7 to the intended temperature at the feed stage 13. The chilled compressed feed gas stream 11 should be cooled to as low a temperature as possible without causing the condensing of condensable components in the gas mixture or freezing of any water present. In other words, the compressed feed gas stream 7 should not be chilled to its dew point. The chilled compressed feed gas stream 11 is typically at a pressure of 160-240 psig and at a temperature of 30-80° F (-1.1℃-26.7℃). One of ordinary skill in the art will recognize that there is a significant temperature differential (30-180°F) between the unchilled and chilled compressed feed gas streams 7, 11.
Myrick further discloses in paragraph 0056, the chilled feed gas stream 11 is fed to the first gas separation membrane module 13, also referred to as the feed stage or the first stage. The first gas separation membrane module includes a pressure vessel, at least one tube sheet, and a polymeric membrane that is selective for the second gas (such as carbon dioxide) over the first gas (such as methane). Those of skill in the art will recognize that such a gas separation membrane module 13 is adapted and configured to produce a permeate gas stream 15 and a retentate gas stream 17. The permeate gas stream 15, hereinafter referred to as the feed stage permeate gas stream 15, is enriched in the second gas and deficient in the first gas compared to the feed gas stream 3. Conversely, the retentate gas stream 17, hereinafter referred to as the feed stage retentate gas stream 17 is enriched in the first gas and deficient in the second gas compared to the feed gas stream 3.
Myrick discloses in paragraph 0057, as typical in the field of gas separation membranes, the feed stage 13 may include a plurality of gas separation membrane modules arranged in parallel in which manifolds are used to feed the cooled, compressed feed gas stream 11 to each of the plurality (of gas separation membrane modules), collect the retentate gas streams 17 from each of the plurality, and collect the permeate gas streams 15 from each of the plurality.
Myrick discloses in paragraph 0059, the feed stage retentate gas stream 17 typically has a pressure of 150-230 psig and a temperature of 30-60° F. Consider a gas mixture comprising the first gas methane at 50 vol % and a second gas carbon dioxide at 50 vol %. Separation of such a gas mixture at the feed stage 13 would typically result in the first retentate gas stream 17 having about 75 vol % methane and 25 vol % carbon dioxide, although the methane and carbon dioxide contents may of course be higher or lower depending upon the composition of the gas mixture and the particular selectivity of the polymeric membrane. One of ordinary skill will recognize that the temperature of the feed stage retentate gas stream 17 is well below the temperature of feed stage retentates typically exhibited by conventional membrane schemes.
Myrick further discloses in paragraph 0060, the feed stage permeate gas stream 15 typically has a pressure of 30-60 psig and a temperature of 40-70° F. Again, consider a gas mixture comprising 50 vol % methane and 50 vol % carbon dioxide. Separation of such a gas mixture at the feed stage 13 would typically result in the feed stage permeate gas stream 15 having about 5 vol % methane, and 95 vol % carbon dioxide, although the methane and carbon dioxide contents may be higher or lower, again depending upon the composition of the gas mixture and the selectivity of the polymeric membrane.
Myrick discloses in paragraph 0061, the feed stage retentate gas stream 17 is fed to the second gas separation membrane module 23, also referred to as the retentate stage or second stage.
Myrick discloses in paragraph 0062, similar to the first gas separation membrane module 13, the second gas separation membrane module 23 includes a pressure vessel, at least one tube sheet, and a polymeric membrane that is selective for the second gas carbon dioxide over the first gas methane. Those of skill in the art will recognize that such a gas separation membrane module is adapted and configured to produce a corresponding permeate gas stream 25 and a retentate gas stream 27. The permeate gas stream 25, hereinafter the second permeate gas stream, is enriched in the second gas and deficient in the first gas compared to the feed stage retentate gas stream 17. Conversely, the retentate stage retentate gas stream 27, hereinafter the second retentate gas stream, is enriched in the first gas and deficient in the second gas compared to the feed stage retentate gas stream 17.
Myrick discloses in paragraph 0063, similar to the feed stage 13, the retentate stage 23 may include a plurality of gas separation membrane modules arranged in parallel in which manifolds are used to feed the remaining portion 21 of the feed stage retentate gas stream 17 to each of the plurality (of gas separation membrane modules), collect the retentate stage retentate gas streams 27 from each of the plurality, and collect the retentate stage permeate gas streams 25 from each of the plurality.
Myrick discloses in paragraph 0065, the retentate stage permeate gas stream 25 is fed to (i.e., recycled to) the suction inlet of the main compressor 5 where it is combined and compressed with the stream of the gas mixture 1. Recycling the retentate stage permeate gas stream 25 allows the substantial amount of the first gas contained therein to be recovered and subjected to membrane separation to remove amounts of the second gas as described above.
Myrick discloses in paragraph 0067, the feed stage permeate gas stream 15 is fed to a third gas separation membrane module, hereinafter referred to as the permeate stage. Similar to the first and second gas separation membrane modules 13, 23, the third gas separation membrane module 31 includes a pressure vessel, at least one tube sheet, and a polymeric membrane that is selective for the second gas carbon dioxide over the first gas methane. Those of skill in the art will recognize that such a gas separation membrane module is adapted and configured to produce a corresponding permeate gas stream 33 and a retentate gas stream 35. The permeate gas stream 33, hereinafter the second permeate gas stream, is enriched in the second gas and deficient in the first gas compared to the permeate stage permeate gas stream 15. Conversely, the retentate gas stream 35, hereinafter the permeate stage retentate gas stream, is enriched in the first gas and deficient in the second gas compared to the feed stage permeate gas stream 15.
Myrick discloses in paragraph 0068, similar to the first and second gas separation membrane modules 13, 23, the permeate stage 31 may include a plurality of gas separation membrane modules arranged in parallel in which manifolds are used to feed the feed stage permeate gas stream 15 to each of the plurality (of gas separation membrane modules), collect the permeate stage retentate gas streams 35 from each of the plurality, and collect the permeate stage permeate gas streams 33 from each of the plurality.
Myrick discloses in paragraph 0072, a portion 37 of the permeate stage retentate gas stream 35 is used as a sweep gas for the permeate stage 31. Those skilled in the art will recognize that configurations for gas separation membrane modules utilizing sweep are well known in the field of gas separation membrane separation and their details need not be duplicated here. Due to the lowered partial pressure of the second gas in the permeate stage permeate gas stream 33 diluted with an amount of the permeate stage retentate gas stream 35, the greater second gas partial pressure difference across the polymeric membrane causes a greater flux of the second gas across the membrane. Thus, removal of second gas from the feed stage permeate gas stream 15 is especially enhanced by the use of the sweep gas. As described above, the permeate stage 31 may include a plurality of the gas separation membrane modules in parallel. In such an embodiment, each single gas separation module may be swept with a portion 37 of the permeate stage retentate gas stream 35 produced by that single module, or alternatively, a portion 37 of the feed gas retentate gas stream 35 collected from the permeate stage 31 may be provided to each of the individual gas separation membrane modules of the permeate stage 31 via a manifold.
It is to be noted, Myrick discloses a gas separation system comprising a compressor, chiller, membrane and gas separation membranes but fails to further disclose a membrane dryer.
However, it is known in the art for a gas separation system to comprise at least one membrane dryer in order to aid in the improvement of the startup and shutdown processes of a gas separation system, as taught by Cook.
Cook discloses in column 2 lines 34-44, one aspect, lies in a start-up process for a membrane gas separation system comprising at least one gas separation membrane module having permeate and nonpermeate sides and at least one membrane dryer module having permeate and nonpermeate sides, with said at least one gas separation membrane module being capable of separating at least one gas component from a gas mixture and said at least one membrane dryer module being capable of separating wet components from said gas mixture.
Cook further discloses in column 2 lines 44-60 and column 3 lines 1-13, the start-up process comprises: passing a pressurized gas mixture into said nonpermeate side of said at least one membrane dryer module to pressurize said at least one membrane dryer module; passing at least a portion of the pressurized gas mixture from said nonpermeate side of said at least one membrane dryer module or a dry gas stream from an external source to said permeate side of said at least one membrane dryer module to purge any moisture in said permeate side of said membrane dryer module; passing at least a portion of the pressurized gas mixture from said nonpermeate side of said at least one membrane dryer module to the nonpermeate side of said at least one gas separation module; permeating at least one gas component of said gas mixture from said nonpermeate side of said at least one gas separation membrane module to the permeate side of said at least one gas separation membrane module; passing at least a portion of the permeated gas from the permeate side of said at least one gas separation membrane module to the permeate side of said at least one membrane dryer module, when said at least one gas separation membrane module reaches its operating pressure and temperature.
Cook discloses in column 4 lines 26-34, as used herein the term "dew point" means temperature at a given pressure wherein water vapor begins to condense. The dew point may be expressed in terms of the water vapor content in a gas stream or membrane modules. The desired dew point is defined as less than 1000 ppm water vapor, preferably less than 250 ppm water vapor in a gas stream or membrane modules.
Cook discloses in column 5 lines 20-24, although the above pressurization methods are preferred, other methods of pressurizing the nonpermeate side (11) of the membrane dryer module (9) can be utilized.
Cook discloses in column 5 lines 25-47, for example, one method of pressurizing the dryer is to start the flow from the dryer simultaneously with the pressure increase. In this method, low pressure gas from the compressor (1) enters and leaves the nonpermeate side (11) of the dryer module (9) with very little moisture permeation until the pressure reaches a high enough level for permeation to start. When the dryer module (9) has been previously operated and the nonpermeated product stream is dry or has been purged dry it is possible for all or some of the moisture in the product stream to be adsorbed by the membrane fiber (15) in the dryer module (9). In this instance a small pulse of high humidity product may exit the nonpermeate side (11) of the dryer module (9). If the downstream gas separation membrane modules (29) can tolerate this product, there is no need for venting. However, if the dryer module (9) has not been previously operated, or has been exposed to high ambient moisture (i.e., the polymer is no longer dehydrated at the start of operation), the duration and level of the product humidity from the nonpermeate side (11) of the dryer module (9) will be greater. In these instances, it may be desirable to vent the dryer product during the initial transient.
Cook discloses in column 5 lines 49-58, another method of pressurizing the dryer module (9) is to bring it to the desired operating pressure and start the nonpermeate product flow from the nonpermeate side (11) of the dryer module (9). In this case, there will be permeation of moisture during the initial flow period and less moisture will remain in the nonpermeate product than that in the first method. Again, the level of humidity during the initial flow period is dependent upon the prior operating history of the dryer module (9), how it was shutdown, the duration of and the conditions during the shutdown.
Cook discloses in column 5 lines 60 and column 6 lines 1-10, an additional method pressurizing the dryer module (9) is to start nonpermeate product flow and pressurization at the same time. However, when the flow reaches a predetermined level, lower than the steady state operating level, it is kept constant during the rest of the transient. This effect increases the area factor of the drying membrane during the initial startup period and can produce a dryer feed to the downstream gas separation membrane modules (29) than when full flow is used.
Cook discloses in column 6 lines 10-25, during the pressurization of the nonpermeate side (11) of the membrane dryer module (9), various gas sources may be used initially to purge the permeate side (13) of the membrane dryer module (9). At least a portion of the pressurized gas mixture leaving the nonpermeate side (11) through a conduit (17), for example, may be supplied to the permeate side (13) of the membrane dryer module (9) through a conduit (10) having a valve (21). Optionally, an external gas source (22), such as a cryogenic liquid tank, may be used to deliver a dry gas to the permeate side (13) of the membrane dryer module (9) to purge the moisture therein. The purge gas and moisture in the permeate side (13) of the membrane dryer module (9) leaves through a conduit (16) having a valve (18).
It would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to add the membrane dryer of Cook to a gas separation system of Myrick. The motivation to do so is at least one membrane dryer in a gas separation system aids in the improvement of the startup and shutdown processes of a gas separation system.
It is to be noted, Myrick discloses a gas separation system comprising a compressor, chiller, membrane and gas separation membranes but fails to further disclose a mixing junction.
However, it is known in the art to add a mixing junction to a gas separation system in order to receive the permeate and non-permeate stream, as taught by Henry.
Henry discloses in the abstract, a method for separating a raw feed gas stream using a plurality of membrane separation stages includes separating a pressurized feed gas stream into a first nonpermeate stream and a first permeate stream, compressing the first permeate stream to form a compressed first permeate stream, separating the compressed first permeate stream into a second nonpermeate stream and a second permeate stream, separating the second permeate stream into a third nonpermeate stream and a third permeate stream, combining the third nonpermeate stream with a raw feed gas stream to form a combined feed stream, compressing the combined feed stream to form a compressed combined feed stream, and combining the second nonpermeate stream with the compressed combined feed stream to form the pressurized feed gas stream.
Henry discloses in paragraph 0012, a first mixing junction having a raw feed gas inlet for receiving a raw feed gas stream, a first recycle inlet operatively connected to the third permeate outlet to receive the third permeate stream, and a first mixture outlet for discharging a combined feed stream consisting of a mixture of the raw feed gas stream and the third permeate stream; a feed compressor having a feed compressor inlet operatively connected to the first mixture outlet to receive the combined feed stream and a feed compressor outlet for discharging a compressed combined feed stream; and a second mixing junction having a combined feed inlet operatively connected to the feed compressor outlet to receive the compressed combined feed stream, a second recycle inlet operatively connected to the second nonpermeate outlet to receive the second nonpermeate stream, and a second mixture outlet operatively connected to the first feed port to supply the pressurized raw feed gas stream consisting of a mixture of the compressed combined feed stream and the second nonpermeate stream to the first membrane stage.
It would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to add the mixing junctions of Henry to the gas separation system of Myrick. The motivation to do so is to add a mixing junction to a gas separation system in order to aid in combining feed streams.
Myrick modified by Cook and Henry have met the limitations of claims 1-7 of the presently claimed invention.
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).
From the teachings of the references, it is apparent that one of ordinary skill in the art would have had a reasonable expectation of success in producing the claimed invention. Therefore, the invention as a whole was prima facie obvious to one of ordinary skill in the art at the time the invention was made, as evidenced by the references, especially in the absence of evidence to the contrary.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Priske (US 2017/0368497) discloses in paragraph 0057, the apparatus, see FIG. 1 by way of example, comprises an interlinking of three membrane separation stages at least. Each stage consists of one or more physical gas separation modules, which are connected directly or indirectly in parallel and/or in series within one stage. The driving force for gas separation in the modules is a partial pressure difference of the permeate gas created between the retentate and permeate sides in the respective membrane separation stage. As mentioned before, the driving force can be generated by the raw gas stream (17) itself respectively the feed stream (5), i.e. combined raw gas stream (17) and recycling streams (9) and/or (10), if the raw gas stream (17) has sufficient pressure. In most cases, however, the partial pressure differential will be generated either by means of a compressor (4) arranged up-stream of the feed stream separation stage, i.e. on the feed side of the feed stream separation stage (1) and/or by means of at least one, preferably one or two, vacuum device(s) (15)(not shown in FIG. 1), arranged in at least one permeate stream of the feed stream separation stage (1), the retentate separation stage (2) and/or the permeate separation stage (3). Preferably vacuum devices (15) are located in the second permeate stream (9) on the permeate side of the retentate separation stage (2) and/or in the third permeate stream (11) on the permeate side permeate separation stage (3). It may optionally be advantageous, in one or more of the membrane separation stages, to generate or to enhance the partial pressure difference by means of a purge gas stream, preferably a permeate-side purge gas stream.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to LATOSHA D HINES whose telephone number is (571)270-5551. The examiner can normally be reached Monday thru Friday 9:00 AM - 6:00 PM.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Prem Singh can be reached at 571-272-6381. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/Latosha Hines/Primary Examiner, Art Unit 1771
