DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Election/Restrictions
Applicant’s election without traverse of Group I (claims 1-3) and Species A3 (Fig. 3) in the reply filed March 15, 2026, is acknowledged and remains of record. Claims 4–8, previously withdrawn under 37 C.F.R. § 1.142(b), have been cancelled, and the withdrawal of those claims is therefore moot.
New claim 22, which requires that the cooled and at least partially liquefied feed oxygen be introduced into an intermediate stage of the oxygen rectification column while an oxygen-containing liquid drawn from an intermediate stage of the medium-pressure nitrogen rectification column is supplied to the top portion of the oxygen rectification column as reflux, is directed to the arrangement of Fig. 5 (apparatus B2) at ¶¶ 0106-0107 of the specification, rather than to elected Species A3 (Fig. 3). Therefore, Claim 22 is withdrawn from further consideration pursuant to 37 C.F.R. § 1.142(b) as being directed to non-elected species.
Status of the Claims
This action is responsive to the Amendment and Remarks filed July 8, 2026, in reply to the Non-Final Office Action mailed April 8, 2026. Claims 4-8 have been cancelled. Claim 9 has been amended. New claims 19–25 have been added. Claims 1-3 and 9-25 are pending and are examined on the merits in this action.
Claim Objections
Claims 15, and 19 are objected to because of the following informalities:
Claim 15 recites the recitation “an absence of a demethanizing the feed oxygen stream” is grammatically incorrect. Correction to, for example, “an absence of demethanizing of the feed oxygen stream” is suggested.
Claim 19, the claim terminates in a comma rather than a period. Each claim must end with a period. See MPEP § 608.01(m). Appropriate correction is required.
Claim Rejections - 35 USC § 112
The following is a quotation of the first paragraph of 35 U.S.C. 112(a):
(a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention.
The following is a quotation of the first paragraph of pre-AIA 35 U.S.C. 112:
The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor of carrying out his invention.
Claims 9–18, 20, 21, and 23–25 are rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, as failing to comply with the written description requirement. The claim(s) contains subject matter which was not described in the specification in such a way as to reasonably convey to one skilled in the relevant art that the inventor or a joint inventor, or for applications subject to pre-AIA 35 U.S.C. 112, the inventor(s), at the time the application was filed, had possession of the claimed invention.
Claim 9 recites, as amended, that the feed oxygen stream “contains high-boiling-point hydrocarbon impurities at no greater than the ppb level” introduces a new matter. The specification as originally filed does not describe a feed oxygen stream that contains high-boiling-point hydrocarbon impurities at any concentration, and it does not describe any parts-per-billion ceiling for such impurities in the feed. To the contrary, paragraph [0007] states that “the oxygen derived from water electrolysis does not contain high-boiling-point components derived from the atmosphere such as methane,” and identifies the only impurities in that stream as “low-boiling-point components dissolved in the water.” The specification thus describes the affirmative absence of the very species that amended claim 9 now affirmatively requires the feed to contain. Every parts-per-billion disclosure in the specification is directed to the ultra-high-purity oxygen product, not to the feed oxygen: paragraph [0002] (“the production of ultra-high-purity oxygen in which the impurity concentration is controlled to no greater than the ppb level”); paragraph [0003] (impurities in the oxygen “controlled to no greater than the ppb level”); paragraph [0018] (ultra-high-purity oxygen defined as an oxygen concentration of 99.99999% or greater); and paragraph [0111] (product argon content reduced to 10 ppb). None of these passages describes the hydrocarbon content of the feed oxygen stream. One of ordinary skill in the art, reading the disclosure as filed, would not reasonably conclude that the inventor had possession of a feed oxygen stream characterized by a bounded, ppb-level hydrocarbon content. The limitation therefore constitutes new matter and is not supported by the original disclosure. See MPEP §§ 2163, 2163.05.
Claim 19 recites that “no additional oxygen-containing fluid is introduced into the oxygen rectification column”; claim 20 recites the same exclusion; and claim 23 recites that the cooled and at least partially liquefied feed oxygen is routed to the oxygen rectification column “without entering an intermediate liquid storage tank.” A negative limitation is adequately described when the specification sets out a reason to exclude the excluded subject matter, or otherwise describes the alternative that is being excluded. See Santarus, Inc. v. Par Pharm., Inc., 694 F.3d 1344, 1351 (Fed. Cir. 2012); MPEP §§ 2163.05, 2173.05(i). The present specification does neither. It nowhere discusses an intermediate liquid storage tank between the main heat exchanger and the oxygen rectification column, and it nowhere states that additional oxygen-containing fluid may be, should be, or is excluded from the oxygen rectification column. The specification in fact describes the opposite of the exclusion recited in claims 19 and 20. Paragraph [0016] and paragraphs [0093]–[0094] describe utilizing an oxygen-containing liquid supplied from the medium-pressure rectification column (2) as a refrigerant in the oxygen condenser (7) and supplying the liquefied low-boiling-point component-containing oxygen stream to the top portion (53) of the oxygen rectification column (5) as reflux liquid. Paragraphs [0106]–[0107] describe drawing an oxygen-containing liquid from an intermediate stage of the nitrogen rectification column (2) through pipeline L22 and supplying it to the column top (53) of the oxygen rectification column (5). The mere absence of a positive recitation, and the absence of an additional stream or a tank from a schematic figure, is not a written description of their exclusion.
Claim 21 recites that “the cooled oxygen-rich liquid is returned to the medium-pressure nitrogen rectification column” introduces a new matter. The specification consistently describes a different destination for the oxygen-rich liquid after it has served as the heating medium in the oxygen vaporizer (6). Paragraphs [0028], [0088], and [0111] describe the oxygen-rich liquid drawn from the bottom portion (21) of the medium-pressure rectification column (2) being introduced through the second oxygen-rich liquid pipeline (L21b) into the oxygen vaporizer (6) and from there into the intermediate stage of the rectification portion (42) of the low-pressure rectification column (4). Paragraph [0094] describes that liquid being introduced, after the oxygen vaporizer (6), into the cold heat liquid portion (71) of the oxygen condenser (7). Paragraphs [0064] and [0102] describe it being introduced into the cold heat liquid portion of the second nitrogen condenser (30). The specification nowhere describes returning the cooled oxygen-rich liquid to the medium-pressure nitrogen rectification column from which it was drawn. The limitation is therefore new matter.
Claims 10–18, 20, and 23–25 are rejected under 35 U.S.C. 112(a) for being dependent upon a rejected claim.
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 9–18, 20, 21, and 23–25 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 9 recites that the feed oxygen stream “contains high-boiling-point hydrocarbon impurities at no greater than the ppb level” renders the claim indefinite because the metes and bounds of this limitation cannot be ascertained with reasonable certainty, for the following reasons. First, “the ppb level” recites a unit of measure without any numerical value; it cannot be determined whether a hydrocarbon concentration of 900 ppb, of 100 ppb, or of 1 ppb falls within “the ppb level,” nor whether a concentration below one part per billion satisfies or fails the limitation. Second, “the ppb level” lacks proper antecedent basis in the claim. Third, the claim does not state whether the recited parts per billion are expressed on a molar, volumetric, or mass basis, which yields materially different bounds for hydrocarbon species in oxygen. Fourth, the specification supplies no definition of the term and no quantitative threshold for hydrocarbon content in the feed oxygen, so the intrinsic record does not resolve the ambiguity. See MPEP § 2173.05(b).
Claim 19 recites that no additional oxygen-containing fluid is introduced into the oxygen rectification column. Claim 1, from which claim 19 depends, affirmatively requires vaporizing liquefied oxygen supplied from a bottom portion of the oxygen rectification column and supplying a vapour stream thereof to the bottom portion of the oxygen rectification column. That vapour stream is an oxygen-containing fluid, and it is introduced into the oxygen rectification column. It is therefore unclear whether the exclusion of claim 19 is intended to reach the vapour stream that claim 1 affirmatively requires, in which case claim 19 would contradict the claim from which it depends, or whether the exclusion is instead confined to fluids supplied from outside the oxygen rectification column. The same ambiguity attends claim 20 with respect to the rising vapour stream affirmatively required by claim 9.
Claims 10–18, 20, 21, and 23–25 are also rejected under 35 U.S.C. 112(b) for being dependent upon a rejected claim.
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, 2, 9, 13-21, 23, and 24 are rejected under 35 U.S.C. § 103 as being unpatentable over Cormier, Sr. et al. (US 5,049,173) in view of Lochner et al. (US 2025/0271208), hereinafter “Lochner ’208”.
In regard to claim 1, Cormier teaches an ultra-high-purity oxygen production method utilizing an air separation unit comprising a main heat exchanger (20), a nitrogen rectification column (rectifier 22), a nitrogen condenser (reboiler/condenser 28), an oxygen rectification column (stripper/fractionator 102), and an oxygen vaporizer (reboiler 286) (col. 4, l. 56 – col. 5, l. 4; col. 5, ll. 5–14, 28–31; col. 6, ll. 8–19; figs. 1–3), wherein the method comprises the steps of:
introducing a feed oxygen comprising low-boiling-point components as impurities (oxygen-containing stream removed from a location of the distillation column at which the removed stream is essentially free of the heavier contaminants comprising hydrocarbons, carbon dioxide, xenon, and krypton, the remaining impurities being the light components) into the oxygen rectification column (102), and ultra-high-purity oxygen from which the low-boiling-point components have been removed is withdrawn as a gas (line 112) or a liquid (line 114) from a lower portion of the oxygen rectification column (102) or from the oxygen vaporizer (Abstract; col. 2, ll. 44–68; col. 5, ll. 15–27, 37–40; figs. 1–3);
utilizing a heating fluid (portion of the crude liquid oxygen fed through line 288) as a heating medium in the oxygen vaporizer (286), wherein the heating fluid is selected from the group consisting of: a portion of feed air cooled in the main heat exchanger (portion of the feed air from line 21 used to reboil the auxiliary column), a portion of the feed oxygen cooled in the main heat exchanger, a liquid or gas withdrawn from a medium-pressure rectification column constituting the nitrogen rectification column (crude liquid oxygen drawn through line 288 from the bottom of rectifier 22), and combinations thereof (col. 6, ll. 8–19, 56–59; col. 7, ll. 1–3; figs. 2, 4);
vaporizing liquefied oxygen supplied from a bottom portion of the oxygen rectification column (at least a portion of the ultra-high-purity oxygen bottoms liquid vaporized by indirect heat exchange in the reboiler disposed at the bottom of stripper 102) (col. 5, ll. 28–30; col. 6, ll. 8–19, 41–44; figs. 1–3); and
supplying a vapour stream thereof to the bottom portion of the oxygen rectification column (the vaporized stream constituting the reboil vapour supplied to the bottom of stripper 102 and driving the upward vapour flow that effects the cryogenic separation) (col. 5, ll. 28–30; col. 6, ll. 15–17, 41–44; figs. 1–3).
With respect to the recitation of a medium-pressure rectification column, Cormier’s rectifier (22) is the higher-pressure rectification column of the system, producing a nitrogen-containing overhead and a crude liquid oxygen bottoms from compressed and cooled feed air. A rectification column of this type is referred to interchangeably in the art as a pressure column, a medium-pressure column, or a lower column. See Lochner ’208, ¶ 0004.
Cormier does not explicitly teach introducing the feed oxygen to a warm end of the main heat exchanger, wherein the feed oxygen is cooled and at least partially liquefied before it is introduced into the oxygen rectification column. Cormier instead draws its oxygen-containing feed as a side stream (line 100) from an intermediate location of the rectifier (22) and delivers it to the fractionator (102) through a pressure-reducing valve (col. 5, ll. 15–23; col. 6, ll. 22–30; figs. 1–3).
However, Lochner ’208 teaches introducing a feed oxygen comprising low-boiling-point components as impurities (dried oxygen stream o obtained as by-product oxygen of water electrolysis in electrolyzer 20, subsequently subjected to rectification for the depletion of argon) to a warm end of a main heat exchanger (4), wherein the feed oxygen is cooled and at least partially liquefied (cooling in the warm part of main heat exchanger 4 followed by complete liquefaction in the cold part thereof), and thereafter introducing the liquefied feed oxygen into an oxygen rectification column (the liquefied and supercooled oxygen stream o fed into further rectification column 12 for further purification) (¶¶ 0026, 0035, 0036, 0061, 0066, 0085, 0091; claims 1, 6, 13; figs. 1, 2).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the method of Cormier to introduce the feed oxygen at the warm end of the main heat exchanger for cooling and at least partial liquefaction before introducing it into the oxygen rectification column, as taught by Lochner ’208, in order to reduce the total energy requirement and the capital expenditure of the installation and to obtain a high-purity oxygen that is not contaminated by mixing with an impure oxygen product, the liquefaction cooling being delivered by the air separation installation already present at the same location (Lochner ’208, ¶¶ 0026–0029). One of ordinary skill would have been motivated to make this modification because Cormier already conducts its process streams through the main heat exchanger (20) to recover and impart refrigeration, and already delivers an oxygen-containing liquid feed to the top of its stripping column through a pressure-reducing valve (Cormier, col. 5, ll. 15–27, 49–67; figs. 1–3), so that an externally supplied oxygen stream liquefied in that same exchanger is delivered to the column in the physical state the column is configured to receive. See MPEP § 2143(I)(A), (G).
The record independently establishes that the combination was within the ordinary creativity of the skilled artisan. Applicant states at ¶ 0007 of the present specification that by-product oxygen from the electrolysis of water “is sometimes used as a feed material for the production of ultra-high-purity oxygen” and that it “would be desirable to control the process by means of cryogenic separation from the point of view of stably removing impurities to a high level,” and states at ¶ 0008 that “it would be reasonable to apply the technology disclosed in Patent Document 2 for cryogenic separation of oxygen gas.” These statements are admissions of prior art and confirm that the proposed combination addresses a recognized need in the field, wholly apart from the express teachings of the applied references. See MPEP § 2129.
The modification does not change the principle of operation of Cormier. The principle on which Cormier operates is the cryogenic stripping of an oxygen-containing feed that is already essentially free of the heavier contaminants, so that a single auxiliary column suffices and the additional distillation column required by the conventional processes is avoided (Cormier, col. 2, ll. 20–33; col. 4, ll. 32–40). Supplying that column with by-product oxygen of water electrolysis preserves that principle rather than altering it, because the electrolysis stream is itself free of the atmospheric hydrocarbons, carbon dioxide, xenon, and krypton that Cormier is at pains to exclude (Lochner ’208, ¶¶ 0026, 0027). Cormier does not require that the heavies-free feed originate from within its own column system; it requires only that the feed be heavies-free. See MPEP § 2143.01(VI).
In regard to claim 2, Cormier teaches the ultra-high-purity oxygen production method according to claim 1, further comprising a step in which an oxygen-containing liquid supplied from the medium-pressure rectification column (portion of the crude liquid oxygen drawn through line 958) is utilized as a refrigerant in an oxygen condenser (reboiler/condenser 962) provided above or in a top portion of the oxygen rectification column (auxiliary column 102), and a low-boiling-point component-containing oxygen stream supplied from the oxygen rectification column (ascending argon-enriched vapour in line 960) is liquefied and supplied to a top portion of the oxygen rectification column as a reflux liquid (reflux line 968) (col. 11, ll. 39–51; fig. 12).
In regard to claim 9, Cormier teaches a method for producing ultra-high-purity oxygen utilizing an integrated air separation unit (the improvement being integrated with the cryogenic distillation column system of an air separation process), the method comprising the steps of:
providing a feed oxygen stream, wherein said feed oxygen stream comprises low-boiling-point impurities (light components, including argon, which are stripped from the stream in the auxiliary column) and contains high-boiling-point hydrocarbon impurities at no greater than the ppb level (the oxygen-containing stream is removed from a location of the distillation column at which it is essentially free of the heavier contaminants comprising hydrocarbons, carbon dioxide, xenon, and krypton) (Abstract; col. 1, ll. 62–67; col. 2, ll. 56–64; col. 4, ll. 15–31);
introducing the feed oxygen stream into an oxygen rectification column (the removed oxygen-containing stream is reduced in pressure across a valve and fed to fractionator 102 to be stripped) (col. 5, ll. 21–23; col. 6, ll. 28–30; figs. 1–3);
drawing an oxygen-rich liquid from a bottom portion of a medium-pressure nitrogen rectification column that has been fed with a cooled and compressed feed air stream (crude liquid oxygen, the oxygen-enriched bottoms liquid, removed through line 38 from the bottom of rectifier 22, the rectifier having been fed through line 21 with feed air compressed in main air compressor 12, freed of water and carbon dioxide in unit 16, and cooled to near its dew point in main heat exchanger 20) (col. 4, l. 56 – col. 5, l. 4; col. 5, ll. 41–42; figs. 1–3);
utilizing said oxygen-rich liquid as a heating medium in an oxygen vaporizer (reboiler 286) disposed in a bottom portion of the oxygen rectification column (stripper 102) to vaporize a portion of liquefied oxygen at the bottom portion of the oxygen rectification column, thereby providing a rising vapour stream to drive cryogenic separation of the low-boiling-point impurities, thereby creating a cooled oxygen-rich liquid (the portion of the crude liquid oxygen fed through line 288 is subcooled in reboiler 286, thereby providing the heat duty required to reboil stripper 102, and is thereafter reduced in pressure and recombined through line 290 with the remaining crude liquid oxygen) (col. 6, ll. 8–19; fig. 2); and
extracting a product ultra-high-purity oxygen stream from a lower portion of the oxygen rectification column (ultra-high-purity oxygen withdrawn as a gas through line 112 and as a liquid through line 114 from the bottom of stripper 102) (Abstract; col. 5, ll. 37–40; col. 6, ll. 50–53; figs. 1–3).
Cormier does not explicitly teach (a) that the feed oxygen stream comprises by-product oxygen generated by water electrolysis; (b) introducing the feed oxygen stream into a warm end of a main heat exchanger of the air separation unit to at least partially condense the feed oxygen stream before introducing it into the oxygen rectification column; or (c) the recited product oxygen concentration of at least 99.99999%.
However, Lochner ’208 teaches, as to limitation (a), providing a feed oxygen stream comprising by-product oxygen generated by water electrolysis (oxygen stream o obtained, together with a hydrogen stream, by subjecting water to electrolysis in electrolyzer 20), that stream being contaminated mainly only with water and not contaminated by mixing with an impure oxygen product, and containing the low-boiling-point impurities for the depletion of which the oxygen product is rectified (¶¶ 0026, 0027, 0035, 0061; claims 1, 6; figs. 1, 2); and, as to limitation (b), introducing that stream into a warm end of a main heat exchanger (4) of the air separation installation, where it is cooled in the warm part of the exchanger and completely liquefied in the cold part thereof, and thereafter feeding the liquefied stream into a further rectification column (12) for further purification (¶¶ 0035, 0036, 0066, 0085, 0091; claims 2, 13; figs. 1, 2).
As to limitation (c), Cormier teaches extracting the product from the lower portion of the oxygen rectification column at ultra-high purity, its disclosure being directed to producing ultra-high-purity oxygen at contaminant concentrations below 10 vppm by cryogenic stripping of a feed that is already essentially free of the heavier contaminants, so that only the light components remain to be removed (Abstract; col. 1, ll. 62–67; col. 2, ll. 56–64). Lochner ’208 in turn specifies the purity required of the oxygen product for the semiconductor fabrication plants it supplies, stating that the nitrogen should typically have approximately 1 ppb, and at most 1000 ppb, of oxygen and that the oxygen should have a comparable purity (¶ 0005). The particular concentration of at least 99.99999% is in any event obtained by selecting the number of theoretical stages and the reflux ratio of the oxygen rectification column, which are ordinary design parameters of a cryogenic rectification column. Where the general conditions of a claim are disclosed in the prior art, discovering the optimum or workable ranges involves only routine skill in the art. See In re Aller, 220 F.2d 454, 456 (CCPA 1955); MPEP § 2144.05(II). The present specification confirms the predictability of this result, reporting at ¶ 0111 that an oxygen rectification column of 60 theoretical plates operated at 1.5 bar(a) reduces a 1 ppm argon feed to a 10 ppb argon product.
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the method of Cormier to supply the oxygen rectification column with by-product oxygen generated by water electrolysis and introduced at the warm end of the main heat exchanger for cooling and at least partial liquefaction, as taught by Lochner ’208, in order to reduce the total energy requirement and the capital expenditure associated with providing nitrogen, oxygen, and hydrogen products, and in order to exploit the high purity of electrolysis oxygen, which is not contaminated by mixing with an impure oxygen product.
In regard to claim 13, the modified Cormier teaches the method as claimed in claim 9, wherein Cormier further comprising: drawing a nitrogen-rich gas from a top portion of the medium-pressure nitrogen rectification column (nitrogen overhead removed from the top of rectifier 22 through line 24); condensing said gas in a nitrogen condenser (the substream fed through line 26 to reboiler/condenser 28, wherein it is liquefied and returned to the top of rectifier 22 through line 30 as reflux); and routing a waste gas stream from above the nitrogen condenser to an expansion turbine to be used as a supplemental process fluid for refrigeration (the vaporized waste stream removed through line 40 from the overhead of the sump area surrounding reboiler/condenser 28, a part of which is expanded in expander 52 and returned through line 54 to main heat exchanger 20 to provide refrigeration) (see Cormier col. 5, ll. 5–10, 41–48, 49–61; figs. 1–3).
In regard to claim 14, the modified Cormier teaches the method as claimed in claim 13, wherein Cormier further comprising withdrawing a top gas stream from the oxygen rectification column (stripper overhead removed from stripper 102 through line 104), mixing the top gas with the waste gas stream downstream of the expansion turbine (the stripper waste stream in line 104 combined with the expanded waste stream from rectifier 22 in line 54 downstream of expander 52), and then warming the mixed waste stream in the main heat exchanger (20) to recover additional cold energy (see Cormier col. 5, ll. 63–67; col. 6, ll. 1–2; figs. 1, 2).
In regard to claim 15, the modified Cormier teaches the method as claimed in claim 9, wherein the method further comprises an absence of a demethanizing the feed oxygen stream prior to entering the oxygen rectification column. Cormier performs no demethanizing step on the stream fed to the oxygen rectification column, the oxygen-containing stream being drawn from a location at which it is essentially free of hydrocarbons so that only stripping of the light components is required, and Cormier expressly distinguishes on this basis the conventional processes that must first process the oxygen feed to remove heavy contaminants in at least one additional distillation column (see Cormier col. 2, ll. 56–64; col. 4, ll. 15–31, 32–40).
The same result follows in the modified process from the source of the feed oxygen. Lochner ’208 teaches that oxygen obtained from water electrolysis is contaminated mainly only with water and is not contaminated by mixing with an impure oxygen product (¶¶ 0026, 0027), so that no demethanizing of that stream is called for.
In regard to claim 16, the modified Cormier teaches the method as claimed in claim 9, further comprising expanding the oxygen-rich liquid after the oxygen-rich liquid has served as the heating medium in the oxygen vaporizer and then introducing said expanded oxygen-rich liquid into a second rectification column of the air separation unit, wherein the second rectification column operates at a lower pressure than the medium-pressure nitrogen rectification column (the oxygen-enriched bottoms liquid removed from rectifier 22 through line 38 is, after passing through the reboiler/condenser, reduced in pressure and fed to low pressure column 200, which operates at a lower pressure than rectifier 22) (see Cormier col. 3, ll. 6–15; col. 5, ll. 41–43; fig. 3).
In regard to claim 17, the modified Cormier teaches the method as claimed in claim 9, wherein Cormier teaches the feed oxygen is expanded in a valve prior to being introduced into a top portion of the oxygen rectification column (the oxygen-containing side stream is reduced in pressure across a valve and fed to fractionator 102, the liquid feed being delivered to the top of the stripper) (Cormier, col. 5, ll. 21–23; col. 6, ll. 28–30; col. 8, ll. 12–15; figs. 1, 3, 7).
Cormier does not explicitly teach that the feed oxygen is fully condensed in the main heat exchanger prior to that expansion.
However, Lochner ’208 teaches that the dried feed oxygen stream is fully condensed in the main heat exchanger, disclosing cooling in the warm part of main heat exchanger (4) followed by complete liquefaction in the cold part thereof (¶¶ 0036, 0085; claim 2; figs. 1, 2).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the method of Cormier to fully condense the feed oxygen in the main heat exchanger before expanding it into the top portion of the oxygen rectification column, as taught by Lochner ’208, in order that the liquefaction cooling be delivered by the air separation installation without the oxygen being mixed with any process stream of the air separation.
In regard to claim 18, the modified Cormier teaches the method as claimed in claim 9, wherein Cormier teaches the liquefied oxygen in the oxygen vaporizer is vaporized solely by latent heat exchange with the oxygen-rich liquid drawn from the medium-pressure nitrogen rectification column, thereby eliminating a need for a dedicated nitrogen heating medium cycle to provide heat to the oxygen vaporizer (in the arrangement of Fig. 2 the heat duty for reboiling stripper 102 is provided by subcooling a portion of the crude liquid oxygen drawn from rectifier 22 through line 288 instead of by condensing a portion of the nitrogen overhead, Cormier presenting that arrangement as the alternative to the nitrogen-condensation heat source of Fig. 1) (see Cormier col. 6, ll. 8–19; fig. 2). The exchange in reboiler 286 is a latent heat exchange as to the liquefied oxygen being vaporized: the oxygen at the bottom of stripper 102 changes phase, absorbing its latent heat of vaporization, and that heat is supplied by the crude liquid oxygen and by no other source.
In regard to claim 19, the modified Cormier teaches the ultra-high-purity oxygen production method according to claim 1, wherein no additional oxygen-containing fluid is introduced into the oxygen rectification column (auxiliary distillation column 402 receives the oxygen-containing feed stream through line 407 together with a reflux consisting of the pure liquid nitrogen stream in line 231 taken from the top of high pressure column 22, so that a pure nitrogen product is produced at the column top and ultra-high-purity oxygen at the column bottom) (see Cormier col. 7, ll. 21–34; fig. 5).
In regard to claim 20, the modified Cormier teaches the method as claimed in claim 9, wherein no additional oxygen-containing fluid is introduced into the oxygen rectification column (auxiliary distillation column 402 receives the oxygen-containing feed stream through line 407 together with a reflux consisting of the pure liquid nitrogen stream in line 231 taken from the top of high pressure column 22) (see Cormier col. 7, ll. 21–34; fig. 5).
In regard to claim 21, the modified Cormier teaches the method as claimed in claim 9. Cormier does not explicitly teach that the cooled oxygen-rich liquid is returned to the medium-pressure nitrogen rectification column, Cormier instead recombining the subcooled crude liquid oxygen through line 290 with the remaining crude liquid oxygen in line 38 (see Cormier col. 6, ll. 8–19; fig. 2).
However, Lochner ’208 teaches returning to the nitrogen rectification column the fluid that has served in the bottoms evaporator of the oxygen rectification column, disclosing that the stream conducted through the bottoms evaporator (14) of the further rectification column (12) is thereafter fed, in a liquefied state, into the air-fed rectification column (11) (¶ 0090; fig. 2).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the method of Cormier to return the cooled oxygen-rich liquid to the medium-pressure nitrogen rectification column, as taught by Lochner ’208, in order to recover that liquid within the column system and thereby reduce the total energy requirement of the installation. One of ordinary skill would have been motivated to make this modification because Cormier itself teaches that reducing the quantity of liquid withdrawn from the main nitrogen column increases the liquid reflux in the bottom section of that column and reduces the detrimental effect of the withdrawal on nitrogen recovery (Cormier, col. 9, ll. 44–51; figs. 8–10), so that returning the spent liquid to that same column serves a benefit Cormier expressly identifies.
In regard to claim 23, the modified method of Cormier in view of Lochner ’208 teaches the method as claimed in claim 9, wherein the cooled and at least partially liquefied feed oxygen is routed continuously from the main heat exchanger directly to the oxygen rectification column without entering an intermediate liquid storage tank (in Lochner ’208 the oxygen stream o, previously liquefied in main heat exchanger 4 and then supercooled in supercooling counterflow unit 5, is fed into further rectification column 12 for further purification, it being the bottoms liquid q of that column, and not the feed to it, that is fed into tank unit 23; and in Cormier the oxygen-containing feed passes from the pressure-reducing valve directly into fractionator 102) (Lochner ’208, ¶ 0091, fig. 2; Cormier, col. 5, ll. 21–23, figs. 1–3). These limitations are taught by the combination applied to claim 9.
In regard to claim 24, the modified Cormier teaches the method as claimed in claim 9, Cormier does not explicitly teach that the feed oxygen stream passes through the main heat exchanger in a set of passages that are fluidly isolated from the feed air, such that the feed oxygen stream remains physically separated from the feed air during the cooling and liquefying steps.
However, Lochner ’208 teaches that the dried oxygen stream is introduced into the air separation installation without being mixed with a process stream of the air separation and is subjected in an unmixed state to liquefaction, that there is preferably no mixing of the oxygen stream from the electrolysis with any process stream of the air separation, and that the main heat exchanger is a plate fin heat exchanger having passages in the form of fluid channels separated from one another and having heat exchange surfaces, connected together in parallel and separated by other passages to form passage groups (¶¶ 0012, 0026, 0035; claims 1, 14; figs. 1, 2).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the method of Cormier to pass the feed oxygen through the main heat exchanger in passages fluidly isolated from the feed air, as taught by Lochner ’208, in order that the liquefaction of the oxygen not interfere with the low-temperature separation process of the air separation and that the high purity of the electrolysis oxygen not be compromised by mixing with an impure oxygen product.
Claim(s) 3, 10-12 and 25 are rejected under 35 U.S.C. 103 as being unpatentable over Cormier and Lochner ’208 as applied to claims 1 or 9 above, and further in view of Lochner (US 2016/0069611 A1), hereinafter “Lochner ’611.”
In regard to claim 3, the modified Cormier teaches the ultra-high-purity oxygen production method according to claim 1, wherein Cormier further teaches warming a process stream in the main heat exchanger (20), withdrawing it, expanding a part of it in an expander (52) to provide refrigeration, and returning the expanded stream (line 54) to the main heat exchanger (20) for further warming (col. 5, ll. 49–67; fig. 1).
The modified Cormier does not explicitly teaches a step in which a portion of the feed oxygen drawn from partway through the main heat exchanger is expanded by an expansion turbine and cooled, after which it is once again supplied to the main heat exchanger.
However, Lochner ’611 teaches drawing a stream from partway through the main heat exchanger (first fluid flow 19 passed to the cold end of main heat exchanger 9 and withdrawn therefrom through line 20 at an intermediate temperature), expanding that stream in an expansion turbine so as to perform work and thereby cooling it (turbo expander 21), and once again supplying the expanded stream to the main heat exchanger (expanded fluid flow 23 heated in main heat exchanger 9 to approximately ambient temperature) (¶¶ 0025–0026, 0040; fig. 1).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the method of Cormier in view of Lochner ’208 to draw a portion of the feed oxygen from partway through the main heat exchanger, expand it in an expansion turbine, and return it to the main heat exchanger, as taught by Lochner ’611, in order to generate within the exchanger the refrigeration required by the process, the mechanical energy recovered in the expansion machine being usable in turn for recompression.
In regard to claim 10, the modified method of Cormier in view of Lochner ’208 teaches the method as claimed in claim 9, wherein the low-boiling-point impurities in the feed oxygen stream include argon and the extracted product ultra-high-purity oxygen stream is depleted of argon (Cormier teaches that argon is the light impurity stripped from the oxygen-containing stream in the stripping column and that the stripping operation yields ultra-high-purity oxygen at the column bottom, and Lochner ’208 requires that the provision of the oxygen product comprise rectification for the depletion of argon) (Cormier, Abstract; col. 1, ll. 20–24, 62–67; col. 5, ll. 15–27; Lochner ’208, ¶¶ 0061, 0066; claim 6).
Cormier in view of Lochner ’208 do not explicitly state that the extracted product ultra-high-purity oxygen stream comprises an argon concentration of 10 ppb or less.
However, Lochner ’611 teaches obtaining a pure oxygen product from a pure oxygen column fed with an oxygen-enriched flow drawn from the nitrogen column at argon purities of less than 10 ppb (¶¶ 0019, 0021, 0042–0044; fig. 1).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the method of Cormier in view of Lochner ’208 to operate the oxygen rectification column so as to yield a product argon concentration of 10 ppb or less, as taught by Lochner ’611, in order to deliver oxygen of the specified degree of purity required by the industrial uses that consume it, which Lochner ’611 identifies as being satisfied only with great difficulty or not at all by conventional plants.
As to the recitation that the low-boiling-point impurities in the feed oxygen stream include argon at a concentration of approximately 1 ppm, that value is not a process step but a characteristic of the feedstock itself. The modified process employs the same feedstock produced by the same process as the claimed invention, namely by-product oxygen generated by the electrolysis of water (Lochner ’208, ¶¶ 0026, 0027, 0035), the argon in that stream originating from the atmospheric gases dissolved in the feed water, as Applicant acknowledges at ¶ 0007 of the present specification. Where the prior art teaches a product made by a substantially identical process from a substantially identical starting material, the claimed characteristic is presumed to be present, and the burden shifts to Applicant to show otherwise. See In re Best, 562 F.2d 1252, 1255 (CCPA 1977); MPEP §§ 2112.01, 2145. In the alternative, the selection of a feed argon content within the range inherent to electrolysis oxygen, and of the corresponding column stage count and reflux ratio, is routine optimization of a result-effective variable. See In re Aller, 220 F.2d 454, 456 (CCPA 1955); MPEP § 2144.05(II)(B).
In regard to claim 11, the modified Cormier teaches the method as claimed in claim 9, wherein Cormier further teaches maintaining the refrigeration balance of the process by splitting a stream, warming a portion in the main heat exchanger (20), expanding a part of it in expander (52), and returning the expanded stream through line (54) to the main heat exchanger (col. 5, ll. 49–67; fig. 1).
The modified Cormier does not explicitly teaches maintaining a heat balance in the main heat exchanger by drawing a portion of the feed oxygen stream from partway through the main heat exchanger, expanding said portion through an expansion turbine to generate refrigeration, and returning the expanded portion to the main heat exchanger.
However, Lochner ’611 teaches drawing a stream from partway through the main heat exchanger (first fluid flow 19 passed to the cold end of main heat exchanger 9 and withdrawn through line 20 at an intermediate temperature), expanding that stream through an expansion turbine to generate refrigeration (turbo expander 21, in which the stream is expanded so as to perform work, the mechanical energy generated being used in part for recompression in cold compressor 30), and returning the expanded stream to the main heat exchanger (expanded fluid flow 23 heated in main heat exchanger 9) (¶¶ 0025–0026, 0040; fig. 1).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the method of Cormier in view of Lochner ’208 to draw a portion of the feed oxygen stream from partway through the main heat exchanger, expand it in an expansion turbine, and return it to the main heat exchanger, as taught by Lochner ’611, in order to generate within the exchanger the refrigeration that the process requires while recovering the expansion work for recompression duty.
In regard to claim 12, the modified Cormier in view of Lochner ’208 teaches the method as claimed in claim 9, wherein Lochner ’208 further teaches operating the nitrogen rectification column at a medium pressure level (high-pressure column operated at a pressure level of 4 to 7 bar, in particular approximately 5.3 bar, higher pressure levels also being usable in either rectification column) and providing the water-containing oxygen stream by high-pressure electrolysis and subjecting it to compression after drying and before liquefaction in the main heat exchanger (¶¶ 0004, 0059, 0060; claims 4, 5).
Cormier and Lochner ’208 do not explicitly teach the recited values of approximately 10 bar(a) for the feed oxygen stream introduced into the main heat exchanger, approximately 7.5 bar(a) for the withdrawal of the oxygen-rich liquid from the medium-pressure column, and approximately 1.5 bar(a) for the operation of the oxygen rectification column.
However, Lochner ’611 teaches operating the nitrogen-producing separation column at an operating pressure of between 6 and 20 bar, preferably approximately 9 bar, with the feed air compressed to an absolute pressure of between 6 and 20 bar, and operating the pure oxygen column at an operating pressure of between 1.3 and 4 bar, preferably approximately 2.5 bar, the oxygen-enriched flow being drawn in the liquid state from an intermediate point of the nitrogen column and delivered to the pure oxygen column (¶¶ 0037, 0038, 0042; fig. 1). Lochner ’611 further teaches that the liquid fraction from which the oxygen product is provided is advantageously handled at a process pressure of 8 to 16 bar, and is raised to an increased pressure of between 2 and 100 bar, preferably approximately 12 bar, before being vaporized in the main heat exchanger (¶¶ 0019, 0044; fig. 1), which range encompasses the recited feed oxygen pressure of approximately 10 bar(a). The recited pressures fall within, or immediately adjacent to, these disclosed operating ranges. Where the claimed values lie inside ranges disclosed by the prior art, a prima facie case of obviousness exists. See MPEP § 2144.05(I). The selection of a particular operating pressure within a disclosed range is, moreover, routine optimization of a result-effective variable, the column pressure governing the relative volatility of the oxygen-argon separation and the temperature driving forces available in the reboiler and the condenser. See In re Aller, 220 F.2d at 456; MPEP § 2144.05(II).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the method of Cormier in view of Lochner ’208 to operate the medium-pressure nitrogen rectification column and the oxygen rectification column at the recited pressures and to supply the feed oxygen at the recited pressure, as taught by Lochner ’611, in order to obtain the temperature difference required to reboil the oxygen column against the oxygen-enriched liquid drawn from the nitrogen column while permitting the oxygen product to be delivered without a pump and its attendant sources of contamination. One of ordinary skill would have been motivated to make this modification because Cormier requires a temperature difference between the crude liquid oxygen serving as the heating medium and the liquefied oxygen being reboiled in the oxygen vaporizer, which is established by the difference between the operating pressures of the two columns (Cormier, col. 6, ll. 8–19; fig. 2). See MPEP § 2143(I)(G).
In regard to claim 25, the modified Cormier teaches the method as claimed in claim 9, but does not explicitly teaches drawing a portion of the feed oxygen stream from partway through the main heat exchanger, expanding said portion of the feed oxygen stream in an expansion turbine to generate cold heat, and returning the expanded portion to the main heat exchanger to maintain a heat balance within the main heat exchanger.
However, Lochner ’611 teaches drawing a stream from partway through the main heat exchanger (first fluid flow 19 delivered to the cold end of main heat exchanger 9 and withdrawn through line 20 at an intermediate temperature), expanding it in an expansion turbine so as to perform work and thereby generate cold (turbo expander 21), and returning the expanded stream to the main heat exchanger for warming (expanded fluid flow 23) (¶¶ 0025–0026, 0040; fig. 1).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the method of Cormier in view of Lochner ’208 to draw a portion of the feed oxygen stream from partway through the main heat exchanger, expand it in an expansion turbine, and return it to the main heat exchanger, as taught by Lochner ’611, in order to generate the refrigeration required by the process within the exchanger itself and to recover the expansion work for recompression duty.
Remarks (Note regarding Lochner ’208)
The following is provided to advance prosecution and to place Applicant on notice of the examiner’s position. It is not a ground of rejection, and no response to this note is required.
In the course of further consideration and/or search conducted for this action, the examiner determined that Lochner ’208 appears, standing alone, to describe each and every limitation of claim 1 as presently drafted, arranged as in the claim. In particular, the embodiment of Fig. 2 of Lochner ’208 discloses an air separation installation comprising a main heat exchanger (4), an air-fed rectification column (11), a condenser evaporator (13), a further rectification column (12) used for oxygen recovery, and a bottoms evaporator (14) disposed in the lower region of that further rectification column and used for boiling its bottoms liquid; the introduction of the dried electrolysis oxygen at the warm end of the main heat exchanger, its cooling and complete liquefaction therein, and its introduction into the further rectification column for further purification; the withdrawal of the resulting oxygen product from the bottoms of that column; and the use, as the heating medium of the bottoms evaporator, of a portion of the feed air compressed in the main air compressor and cooled in the main heat exchanger, and of a side stream drawn from the air-fed rectification column. See Lochner ’208, ¶¶ 0004, 0005, 0012, 0013, 0025, 0026, 0035, 0036, 0061, 0066, 0085, 0089–0091; claims 1, 2, 6, 12, 13; figs. 1, 2.
Lochner ’208 qualifies as prior art under 35 U.S.C. § 102(a)(2) for the reasons stated in the section titled “Prior art status of Lochner ’208” above. Should claim 1 be maintained in substantially its present form in a subsequent submission, a rejection of that claim under 35 U.S.C. § 102(a)(2) as anticipated by Lochner ’208 may be made in a subsequent Office action. Applicant may wish to take this into account in framing any after-final amendment, request for continued examination, or appeal.
Response to Arguments
Applicant's arguments filed 07/08/2026 have been fully considered but they are not persuasive, unless otherwise noted below.
Applicant’s argument that the § 112(b) rejection was directed to the wrong claim and that “selected from the group consisting of” is proper Markush wording.
In response, this argument is persuasive. The rejection of claims 9–18 under 35 U.S.C. § 112(b) based on the recitation of “the group” is withdrawn. The Markush recitation of claim 1 is proper.
Applicant’s argument that Lochner ’208 teaches away from combination with Cormier
In response, this argument is not persuasive. The quoted sentence of ¶ 0026 is about mixing. Read with the sentences that precede it in the same paragraph, it states only that the process streams of the air separation - streams derived from the feed air - are not commingled with the electrolysis oxygen in order to purify it. It does not address, much less discourage, rectifying that oxygen. Lochner ’208 elsewhere directs the very step Applicant says it forecloses. The provision of the oxygen product may comprise further purification, in particular rectification for the depletion of argon (¶ 0061); the liquid oxygen stream may be fed into the further rectification column for further purification (¶ 0066); and in the embodiment of Fig. 2 the liquefied and supercooled oxygen stream o is fed into further rectification column 12 for that purpose (¶ 0091). Claims 6, 12, and 13 recite the same subject matter.
Furthermore, a reference teaches away only where it criticizes, discredits, or otherwise discourages the claimed solution, and a stated preference is not a teaching away. In re Fulton, 391 F.3d 1195, 1201 (Fed. Cir. 2004); In re Gurley, 27 F.3d 551, 553 (Fed. Cir. 1994). Lochner ’208 does neither. Nor do the rejections rest on the proposition Applicant attacks: the electrolysis oxygen is liquefied in the main heat exchanger as Lochner ’208 teaches and then rectified in a dedicated oxygen rectification column reboiled against crude liquid oxygen as Cormier teaches, without commingling with any air-derived process stream. The motivation to combine is supplied by the stated objectives of Lochner ’208 (¶¶ 0026–0029), by Cormier’s teaching that a heavies-free feed requires only stripping of the light components (col. 2, ll. 20–33; col. 4, ll. 32–40), and by Applicant’s admissions at ¶¶ 0007–0008.
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.
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/W.M/Examiner, Art Unit 3763
/FRANTZ F JULES/Supervisory Patent Examiner, Art Unit 3763
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