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 species A3 – figure 3 (encompassing claims 1-15) in the reply filed on September 9, 2026 is acknowledged.
Claim Objections
Claim 11 is objected to for reciting "the second gas (27)" where claim 10 refers to the same stream as "the compressed second gas (27)." Applicant is advised to refer to the stream consistently. Appropriate correction is required.
Claim Interpretation
The following is a quotation of 35 U.S.C. 112(f):
(f) Element in Claim for a Combination. – An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof.
The following is a quotation of pre-AIA 35 U.S.C. 112, sixth paragraph:
An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof.
The claims in this application are given their broadest reasonable interpretation using the plain meaning of the claim language in light of the specification as it would be understood by one of ordinary skill in the art. The broadest reasonable interpretation of a claim element (also commonly referred to as a claim limitation) is limited by the description in the specification when 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, is invoked.
As explained in MPEP § 2181, subsection I, claim limitations that meet the following three-prong test will be interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph:
(A) the claim limitation uses the term “means” or “step” or a term used as a substitute for “means” that is a generic placeholder (also called a nonce term or a non-structural term having no specific structural meaning) for performing the claimed function;
(B) the term “means” or “step” or the generic placeholder is modified by functional language, typically, but not always linked by the transition word “for” (e.g., “means for”) or another linking word or phrase, such as “configured to” or “so that”; and
(C) the term “means” or “step” or the generic placeholder is not modified by sufficient structure, material, or acts for performing the claimed function.
Use of the word “means” (or “step”) in a claim with functional language creates a rebuttable presumption that the claim limitation is to be treated in accordance with 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph. The presumption that the claim limitation is interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, is rebutted when the claim limitation recites sufficient structure, material, or acts to entirely perform the recited function.
Absence of the word “means” (or “step”) in a claim creates a rebuttable presumption that the claim limitation is not to be treated in accordance with 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph. The presumption that the claim limitation is not interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, is rebutted when the claim limitation recites function without reciting sufficient structure, material or acts to entirely perform the recited function.
Claim limitations in this application that use the word “means” (or “step”) are being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, except as otherwise indicated in an Office action. Conversely, claim limitations in this application that do not use the word “means” (or “step”) are not being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, except as otherwise indicated in an Office action.
Claim 15 recites limitations that invoke 35 U.S.C. § 112(f) because they use the generic placeholder "means" coupled with functional language, without reciting sufficient structure to perform the recited function:
"means for separation of the cooled feed stream by partial condensation (S1) and/or distillation (K1)";
"means for sending the feed stream to be cooled in the heat exchanger (E1)...";
"means for sending cooled feed stream from the heat exchanger to the separation means...";
"expansion means";
"means for sending at least part of the first liquid to be expanded in the expansion means...";
"means for sending the second liquid to be at least partially vaporized in the heat exchanger (E1) or an auxiliary heat exchanger (E2)...";
"means for sending the second gas to the compressor...";
"means for sending the compressed second gas from the compressor to the heat exchanger to be cooled";
"means for sending the compressed cooled second gas from the heat exchanger to the bottom of the scrubber column"; and "means for removing a bottom liquid of the scrubber column enriched in the at least one heavier component and containing carbon dioxide and for removing a top gas of the scrubber column depleted in the at least one heavier component" (a single means-plus-function limitation reciting two functions).
Because each of these limitations meets the three-prong test of MPEP § 2181(I) (the claim uses "means," coupled with functional language, and no definite structure is recited to perform the recited function), each is construed under 35 U.S.C. § 112(f) to cover the corresponding structure disclosed in the specification, and equivalents thereof. The corresponding structure for "means for separation... by partial condensation (S1) and/or distillation (K1)" is a phase separator (S1) and/or a distillation column (K1) (spec. ¶¶ 0053-0054; Figs. 1-3). The corresponding structure for "expansion means" is a valve (spec. ¶ 0057: "the other part 16 being expanded in a valve"). The corresponding structure for each "means for sending..." limitation is a conduit or pipe interconnecting the recited components, as generically depicted in Figures 1-3 and described throughout the specification (spec. ¶¶ 0053-0072), without further structural specificity disclosed. The corresponding structure for "means for removing a bottom liquid... and for removing a top gas..." is likewise a conduit at the respective bottom and top outlets of the scrubber column.
If applicant does not intend to have this/these limitation(s) interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, applicant may: (1) amend the claim limitation(s) to avoid it/them being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph (e.g., by reciting sufficient structure to perform the claimed function); or (2) present a sufficient showing that the claim limitation(s) recite(s) sufficient structure to perform the claimed function so as to avoid it/them being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph.
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 1-15 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 1 recites a scrubber column fed at the bottom with a compressed, cooled second gas and washed at the top with liquid CO2, so as to produce a bottom liquid "enriched in the at least one heavier component" and a top gas "depleted in the at least one heavier component," where the heavier component may be "another component such as a hydrocarbon, mercury" and not merely NOx (spec. ¶ 0078). Every quantitative or mechanistic teaching in the specification concerning how the recited scrubber column achieves this enrichment/depletion is tied specifically to NOx chemistry — e.g., cooling the feed gas is said to maximize "the NO conversion to NO2... favored by cold temperatures" upstream of the scrubbing step, which is what "minimize[s]" the heavier-component content of the CO2 product "without the need of adding any reactor to convert NO to NO2" (spec. ¶¶ 0063-0064), and the auxiliary-heat-exchanger partial-vaporization scheme of claims 6-9 is expressly calibrated "to avoid reaching the NOx solidification point" (spec. ¶ 0069). No working example, data, or process guidance is provided for scrubbing a heavier hydrocarbon or elemental mercury impurity using this liquid-CO2-wash scrubber-column architecture, and the solubility, freezing behavior, and vapor/liquid distribution of a heavy hydrocarbon or of mercury in a cryogenic CO2-wash column differ materially from those of NOx species. One of ordinary skill accordingly could not practice the full functionally-defined genus of claim 1 (any "component heavier than CO2") using the specifically disclosed process without undue experimentation to determine suitable operating conditions (wash-liquid rate, column pressure/temperature, purge composition) for each different class of heavier impurity. See In re Wands, 858 F.2d 731 (Fed. Cir. 1988) (breadth of the claims, amount of direction/guidance and working examples, and unpredictability of the art are among the relevant factors).
Claim 15, as an independent apparatus claim, separately and independently recites this same unbounded genus — "means for removing a bottom liquid of the scrubber column enriched in the at least one heavier component" and "means for removing... a top gas of the scrubber column depleted in the at least one heavier component," with no limitation to NOx — and is rejected for the same reasons set forth above with respect to claim 1.
This rejection may be overcome by amending claim 1 (and claim 15) to recite that the at least one heavier component is an oxide of nitrogen (NOx), consistent with claim 12, or by identifying disclosure elsewhere in the specification that provides the guidance needed for the broader genus.
Claims 2-14 are also 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 1-15 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 1 recites, in step a), "cooling the feed stream in a heat exchanger," and, in step c), "at least partial vaporization of the second liquid in the heat exchanger (E1) or an auxiliary heat exchanger (E2)," thereby introducing two distinct, alternatively-recited heat exchangers. Step e) then recites "cooling of the compressed second gas in the heat exchanger," without a reference character and without specifying which of the two previously-introduced heat exchangers is meant. Because step c) leaves open whether the second liquid - and, in consequence, the second gas derived from it - is vaporized in the heat exchanger of step a) or in the auxiliary heat exchanger (E2), a reader cannot determine with reasonable certainty which structure "the heat exchanger" of step e) refers back to. This renders the metes and bounds of step e), and of every claim depending from claim 1, indefinite.
Claim 1, step a), recites cooling the feed stream "to a temperature less than -30°C or less than -45°C, preferably as low as -55°C” renders the claim indefinite because the recitation sets forth a broad outer boundary (less than -30°C), a narrower alternative boundary (less than -45°C), and a still narrower boundary introduced by "preferably" (as low as -55°C), without indicating which of these boundaries defines the actual metes and bounds of the claimed temperature. Because "preferably" language is ordinarily treated as non-limiting, exemplary language rather than a claim limitation, a reader cannot determine with reasonable certainty whether the claim requires only "less than -30°C," requires "less than -45°C," or is further limited toward "as low as -55°C." Reciting a broad range together with a narrower, "preferably"-qualified sub-range of the same parameter, without clearly indicating which range is limiting, renders the claim indefinite. See MPEP § 2173.05(c).
Claim 1, step d), recites the identical defect for a different parameter: compressing the second gas "up to above 8bara, preferably above15 bara." This recitation likewise presents a broad outer boundary (above 8 bara) together with a narrower, "preferably"-qualified boundary (above 15 bara), without indicating which boundary is limiting. For the same reasons given above with respect to step a), it cannot be determined with reasonable certainty whether claim 1 requires only that the second gas be compressed to "above 8 bara" or whether it is further limited to "above 15 bara." See MPEP § 2173.05(c).
Claim 6 recites "part of the bottom liquid of the distillation column is partially vaporized..."; claim 8 recites "the bottom liquid of the distillation column (K1)"; and claim 9 recites "part... of the bottom liquid of the distillation column (K1) is vaporized...." renders the claim indefinite because claim 1 itself never recites "a distillation column" as a structural element; it recites only that the cooled feed stream is separated "by partial condensation (S1) and/or distillation (K1)," where "distillation (K1)" denotes a step qualified by a parenthetical reference character, not an antecedent recitation of "a distillation column." The only claim that affirmatively introduces "a distillation column (K1)" as a structural element is claim 5. Therefore, the limitation lacks antecedent basis for "the distillation column," rendering their scope indefinite.
Claim 11 recites that "the second gas (27) is cooled to below a temperature close to its dew point, between the dew point and the dew point +25°C" renders the claim indefinite because the limitation purports to define a single temperature ("a temperature close to its dew point") by reference to a range ("between the dew point and the dew point +25°C") and then further specifies that the gas is cooled to "below" that range-defined temperature, such that it cannot be determined with reasonable certainty what temperature or range of temperatures the claim actually requires — for example, whether "below" modifies the low end of the range (the dew point itself) or the high end (dew point +25°C). The ambiguity is compounded because claim 11 can depend from claim 1 directly and thus need not be read together with claim 10's differently-worded range ("within 5°C of its dewpoint"), leaving it unclear how the two temperature recitations for the same stream are meant to relate when both are in effect. Clarification is required.
Claim 15, as an independent apparatus claim, separately and independently recites the corresponding limitation - "means for sending the compressed second gas from the compressor to the heat exchanger to be cooled" - immediately after reciting "means for sending the second liquid to be at least partially vaporized in the heat exchanger (E1) or an auxiliary heat exchanger (E2)," which likewise introduces two distinct, alternatively-recited heat exchangers. For the same reason given above with respect to claim 1, it cannot be determined with reasonable certainty whether "the heat exchanger" in this later-recited means-for-sending limitation refers to the heat exchanger (E1) or to the auxiliary heat exchanger (E2).
Claim 15, also recites both defects identified above in claim 1. First, claim 15 recites the identical temperature defect of step a): "means for sending the feed stream to be cooled in the heat exchanger (E1) to a temperature less than -30° C. or less than -45° C., preferably as low as -55° C." For the same reasons given above, it cannot be determined with reasonable certainty whether claim 15 requires only that the feed stream be cooled to "less than -30° C.," to "less than -45° C.," or is further limited toward "as low as -55° C." Second, claim 15 separately recites the identical pressure defect of step d): "means for sending the second gas to the compressor to be compressed gas up to above 8 bara, preferably above 15 bara forming a compressed second gas." For the same reasons given above, it cannot be determined with reasonable certainty whether claim 15 requires the compressor to compress the second gas only "up to above 8 bara" or whether it is further limited to "above 15 bara."
Claims 2-5, 7, 9, 10 and 12-14 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 1-5, 9, 12, 13, and 15 are rejected under 35 U.S.C. § 103 as being unpatentable over Murino Michele et al. (FR 3,127,558 A1; citations to paragraph numbers of the certified English translation of record is provided with office action) in view of White et al. (US 2008/0173585 A1).
In regard to claim 1, Murino teaches a process for separating CO2 from a feed stream (gas flow 1) containing at least CO2 and at least one lighter component chosen among oxygen, nitrogen, argon, methane, CO and hydrogen ("The gas flow 1 contains CO2 and at least one lighter component which may be hydrogen, carbon monoxide, nitrogen or oxygen. In this example, the gas flow is rich in nitrogen") (¶ 0053; Fig. 3) and at least one component heavier than CO2 (NOx, e.g., NO2; "The N column is a NOx removal column for substances heavier than CO2... Since NO is lighter than CO2, the N column is used to remove nitrogen dioxide (NO2)... if present in the liquid") (¶ 0060; Fig. 3), comprising the following steps:
a) cooling the feed stream in a heat exchanger (first heat exchanger E) to a temperature less than -30°C or less than -45°C ("The cooled gas flow in the cooler R5 downstream of the last stage is cooled to a temperature below -50°C in a first heat exchanger E") (¶ 0054; Fig. 3), and separation of the cooled feed stream by partial condensation (phase separator S; "The gas flow 1 partially condenses in the first heat exchanger E and the two-phase flow formed is separated in a phase separator S") (¶ 0055; Fig. 3) and/or distillation (first distillation column C; "sent to the top of a distillation column C from which a liquid 9... is drawn off into a tank") (¶ 0058; Fig. 3) producing a first liquid (liquid 9) enriched in CO2 and the at least one heavier component and depleted in the at least one lighter component ("a liquid 9 enriched in CO2 and depleted in at least one light component is drawn off into a tank") (¶ 0058; Fig. 3) and a first gas (overhead gas 7) depleted in CO2 and the at least one heavier component and enriched in the at least one lighter component ("The overhead gas 7 from column C is heated in the first exchanger E and is enriched with light components from the liquid 5, for example oxygen and/or nitrogen and/or methane and/or NO") (¶ 0059; Fig. 3);
f) sending the (compressed, cooled) second gas [addressed below] to the bottom of a scrubber column (second distillation/washing column N, fed at the top by liquid CO2; "the other part 19 is sent to feed the tank of column N in gaseous form") (¶ 0058; Fig. 3); "[i]n this flow-fed column, at least one impurity heavier than CO2 is washed by an intermediate reflux of CO2 and a top reflux of pure CO2" (¶ 0061; Fig. 3); and
g) removing a bottom liquid (liquid 25) of the scrubber column enriched in the at least one heavier component and containing carbon dioxide ("Liquid 25 enriched in NOx heavier than CO2, such as NO2, is drawn from the tank of column N") (¶ 0062; Fig. 3) and a top gas (overhead gas 21) of the scrubber column depleted in the at least one heavier component ("The leading gas 21 of column N constitutes the CO2-rich gaseous product in this example") (¶ 0064; Fig. 3).
Murino does not expressly teach step b) expanding at least part of the first liquid to produce a second liquid, step c) at least partially vaporizing the second liquid to produce a second gas, step d) compressing the second gas up to above 8 bara (preferably above 15 bara) to form a compressed second gas, or step e) cooling the compressed second gas, all prior to step f). Instead, Murino teaches pressurizing part of the first liquid with a pump (pump P) and vaporizing it directly in the first heat exchanger (E) to form the vapor stream ultimately sent to the bottom of column N, without first reducing the pressure of the liquid by expansion and without thereafter re-compressing the resulting vapor in a gas compressor.
However, White teaches, in a low-temperature CO2 purification process, b) expanding at least part of a first CO2-enriched liquid to produce a second liquid ("A stream 4 of first carbon dioxide-enriched liquid is reduced in pressure in valve V101 to about 18 bar to produce a stream 5 of reduced pressure first carbon dioxide-enriched liquid" (¶ [0020]; Fig. 1); "The pressure of stream 13 is reduced in valve V102 to 8.7 bar to produce a stream 15 of reduced pressure second carbon dioxide-enriched liquid" (¶ [0022]; Fig. 1)); c) at least partially vaporizing the second liquid in the heat exchanger to produce a second gas ("which is vaporized by indirect heat exchange in heat exchanger E101 to provide refrigeration and to produce a stream 6 of first carbon dioxide-enriched gas" (¶ [0020]; Fig. 1); "Stream 15 is vaporized and warmed by indirect heat exchange in the heat exchangers E101, E102... to produce a stream 16 of second carbon dioxide-enriched gas" (¶ [0022]; Fig. 1)); d) compression of the second gas up to above 8 bara forming a compressed second gas ("Stream 16 is compressed in the first stage K102 of a multi-stage centrifugal carbon dioxide compressor to produce a stream 17 of compressed carbon dioxide gas at a pressure of about 18 bar"; "the combined stream is further compressed in the second or further stage(s) K101 of the compressor to produce a stream 19 of further compressed carbon dioxide gas at a pressure of about 110 bar" (¶ [0024]; Fig. 1)); and e) cooling of the compressed second gas ("Heat of compression is removed from stream 17 in an intercooler E104... Heat of compression is removed from stream 19 in an aftercooler E105" (¶ [0024]; 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 CO2/NOx separation process of Murino to expand a portion of the CO2-enriched first liquid to a reduced pressure to produce a second liquid, vaporize the second liquid to produce a second gas, and compress the resulting second gas in a multi-stage centrifugal compressor to a delivery pressure above 8 bara with intercooling, as taught by White, in order to generate additional process refrigeration by vaporizing the CO2-rich liquid at a reduced pressure/temperature while still delivering the vapor onward at the pressure required for downstream processing. One of ordinary skill would have been motivated to make this modification because Murino's own apparatus already uses expansion valves and vaporization of CO2-rich liquid, together with multi-stage compression and intercooling, as a source of process refrigeration and pressure staging elsewhere in the same cold box, such that substituting White's known expand-vaporize-compress-cool sequence for Murino's liquid-pump-and-vaporize arrangement, in generating the vapor feed to column N, is no more than the use of a known technique to improve a similar device or process in the same way, yielding a predictable result. See MPEP § 2143(I)(x).
In regard to claim 2, the modified Murino teaches the process of claim 1, wherein Murino further teaches the top gas (overhead gas 21) of the scrubber column is enriched in carbon dioxide and depleted in the at least one heavier component ("The overhead gas 21 from column N constitutes the purified product in the at least one heavier impurity") (¶ 0043; Fig. 2), the top gas is compressed in a compressor (compression stages C5, C6, C7; "is heated in the first exchanger E before being compressed in a first compression stage C5 driven by the turbine T. After cooling in R6, the flow is divided..., the remainder 27 being compressed in the compression stages C6, C7 to form a pressurized gaseous product") (¶ 0043; Fig. 2), and part (stream 27) of the compressed top gas forms the product of the process ("The compressed gas in C7 constitutes the CO2-rich gaseous product in this example") (¶ 0043; Fig. 2).
In regard to claim 3, the modified Murino teaches the process of claim 2, wherein Murino, in an alternative disclosed embodiment employing the same overhead-gas compression train (C5, C6, C7), further teaches that the compressed top gas forming the product is at least in part liquefied to form a liquid product: "[t]he leading gas 21 of column N constitutes the CO2-rich gaseous product in this example. This gas, enriched in CO2 and depleted in at least one heavy component, is condensed in a heat exchanger 22... Part 28 is returned to column N as reflux and the remainder 24 of the liquid constitutes a product of the process" (¶ 0064; Fig. 3).
In regard to claim 4, the modified Murino teaches the process of claim 2, wherein Murino further teaches part (stream 23) of the compressed top gas is liquefied in the heat exchanger (E) ("a part 23 being condensed in the first exchanger E") (¶ 0043; Fig. 2) and sent to the scrubber column (column N) as wash liquid ("Part 23 is returned to the top of column N as reflux") (¶ 0044; Fig. 2).
In regard to claim 5, the modified Murino teaches the process of claim 1, wherein Murino further teaches the feed stream is separated by partial condensation and distillation in a distillation column (column C) (¶ 0058; Fig. 3) and part (stream 11) of the first liquid is removed from the distillation column, vaporized in the heat exchanger (heat exchanger E, via pump P) and sent to the bottom of the distillation column ("Part of the liquid is sent to vaporize in the first heat exchanger E, part 11 of the vaporized liquid is sent to the tank of column C as reboiling") (¶ 0058; Fig. 3).
In regard to claim 9, the modified Murino in view of White teaches the process of claim 1, wherein Murino further teaches part (stream 19, derived from bottom liquid 9) of the bottom liquid of the distillation column (column C) is vaporized in the heat exchanger (heat exchanger E, as modified by White's teaching of first and second heat exchangers E101, E102 applied to the analogous vaporization step) producing the second gas ("the other part 19 is sent to feed the tank of column N in gaseous form") (¶ 0058; Fig. 3).
In regard to claim 12, the modified Murino teaches the process of claim 1, wherein Murino further teaches the at least one heavier component is an NOx ("The N column is a NOx removal column for substances heavier than CO2, NOx being a designation covering the following compounds: nitrogen monoxide (NO), nitrogen dioxide (NO2)...") (¶ 0060; Fig. 3).
In regard to claim 13, the modified Murino teaches the process of claim 1, wherein Murino further teaches the bottom liquid (liquid 25) of the scrubber column (column N) is vaporized in the heat exchanger (E1) ("Liquid 25... is drawn from the tank of column N. Liquid 25 is heated in the exchanger E") (¶ 0062; Fig. 3).
In regard to claim 15, Murino teaches an apparatus for separating CO2 from a feed stream containing at least CO2 and at least one lighter component chosen among oxygen, nitrogen, argon, methane, CO and hydrogen and at least one component heavier than CO2 (¶¶ 0053, 0060; Fig. 3), comprising:
a heat exchanger (E1) (Murino's first heat exchanger E; ¶ 0014; Figs. 2-3: "a first heat exchanger");
means for separation of the cooled feed stream by partial condensation (S1) and/or distillation (K1) (Murino's phase separator S and distillation column C; ¶ 0014; Figs. 2-3: "a first distillation column... means for supplying the cooled gas in the first heat exchanger to be separated at low temperature, at least by distillation in the first distillation column, to produce a liquid enriched in CO2 and depleted in the component lighter than CO2, and a gas depleted in CO2 and enriched in the component lighter than CO2," construed per the Claim Interpretation section above);
means for sending the feed stream to be cooled in the heat exchanger (E1) to a temperature less than -30°C or less than -45°C (the conduit delivering gas flow 1 to heat exchanger E) (¶¶ 0014, 0054; Figs. 2-3: "a conduit for supplying the compressed gas to be cooled in the first heat exchanger");
means for sending cooled feed stream from the heat exchanger to the separation means to be separated by partial condensation (S1) and/or distillation (K1), producing a first liquid (liquid 9) enriched in CO2 and the at least one heavier component and depleted in the at least one lighter component and a first gas (overhead gas 7) depleted in CO2 and the at least one heavier component and enriched in the at least one lighter component (¶¶ 0014, 0055, 0058-0059; Figs. 2-3);
a scrubber column (K2) (Murino's second distillation column N; ¶ 0014; Figs. 2-3: "a second distillation column");
a conduit for sending liquid CO2 to the top of the scrubber column (the conduit returning condensed stream 23 to the top of column N as reflux) (¶ 0044; Fig. 2: "Part 23 is returned to the top of column N as reflux");
means for removing a bottom liquid of the scrubber column enriched in the at least one heavier component and containing carbon dioxide (the conduit withdrawing liquid 25 from the bottom of column N) (¶¶ 0014, 0062; Figs. 2-3: "means for drawing off a liquid depleted in CO2 and enriched in at least one heavier component from the second column"); and
means for removing a top gas of the scrubber column depleted in the at least one heavier component (the conduit withdrawing overhead gas 21 from column N) (¶¶ 0014, 0064; Figs. 2-3: "means for drawing off a gas enriched in CO2 and depleted in at least one heavier component at the top of the second column as a product").
Murino does not expressly teach expansion means; means for sending at least part of the first liquid to be expanded in the expansion means, said expansion producing a second liquid; means for sending the second liquid to be at least partially vaporized in the heat exchanger (E1) or an auxiliary heat exchanger (E2) producing a second gas; a compressor (C1, C2); means for sending the second gas to the compressor to be compressed gas up to above 8 bara, preferably above 15 bara forming a compressed second gas; means for sending the compressed second gas from the compressor to the heat exchanger to be cooled; or means for sending the compressed cooled second gas from the heat exchanger to the bottom of the scrubber column. Instead, Murino's own apparatus recites an expansion means used only to send an expanded liquid portion to the second distillation column in liquid form as reflux (¶ 0014; Figs. 2-3: "an expansion means, and a conduit for supplying a first portion of the CO2-enriched liquid to be expanded in the [expansion] means... a conduit for sending the first [expanded] portion to the second distillation column in liquid form"), and separately teaches pressurizing another liquid portion with a pump and vaporizing it directly in the first heat exchanger to form the vapor sent to the bottom of the second column, without any gas compressor downstream of that vaporization step ("the other part 19 is sent to feed the tank of column N in gaseous form") (¶ 0058; Fig. 3).
However, White teaches, in an analogous low-temperature CO2 purification apparatus, expansion means for reducing the pressure of a CO2-enriched liquid to produce a second liquid ("A stream 4 of first carbon dioxide-enriched liquid is reduced in pressure in valve V101 to about 18 bar to produce a stream 5 of reduced pressure first carbon dioxide-enriched liquid" (¶ [0020]; Fig. 1)); means for sending the second liquid to be vaporized in a heat exchanger to produce a second gas ("which is vaporized by indirect heat exchange in heat exchanger E101 to provide refrigeration and to produce a stream 6 of first carbon dioxide-enriched gas" (¶ [0020]; Fig. 1)); a compressor for compressing the second gas to a delivery pressure above 8 bara ("Stream 16 is compressed in the first stage K102 of a multi-stage centrifugal carbon dioxide compressor to produce a stream 17 of compressed carbon dioxide gas at a pressure of about 18 bar... the combined stream is further compressed in the second or further stage(s) K101 of the compressor to produce a stream 19 of further compressed carbon dioxide gas at a pressure of about 110 bar" (¶ [0024]; Fig. 1)); and means for cooling the compressed second gas ("Heat of compression is removed from stream 17 in an intercooler E104... Heat of compression is removed from stream 19 in an aftercooler E105" (¶ [0024]; 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 apparatus of Murino to include expansion means for reducing the pressure of the first liquid to produce a second liquid, a heat exchanger arrangement for vaporizing the second liquid to produce a second gas, a compressor for compressing the second gas to a delivery pressure above 8 bara, and a heat exchanger for cooling the compressed second gas before it is sent to the bottom of the scrubber column, as taught by White, in order to generate additional process refrigeration by vaporizing the CO2-rich liquid at a reduced pressure/temperature while still delivering the vapor onward at the pressure required for delivery to the scrubber column.
Claim(s) 6, 7, 8, and 14 are rejected under 35 U.S.C. 103 as being unpatentable over Murino and White as applied to claim 1 above, and further in view of Briglia et al. (US 2015/0253076 A1).
In regard to claim 6, the modified Murino teaches the process of claim 1, including part of the bottom liquid of the distillation column (column C, i.e., stream 19 derived from liquid 9) being vaporized in the heat exchanger to produce the second gas, as set forth above.
The modified Murino does not expressly teach that this vaporization is only partial, such that it also produces a liquid enriched in the heavier component (i.e., a residual, unvaporized liquid fraction), as opposed to complete vaporization of the stream.
However, Briglia teaches, in an analogous low-temperature CO2 purification process, that part of a bottom liquid of a distillation column ("the liquid 33 originating from the bottom of the column") is expanded and then partially - rather than completely - vaporized in a second, auxiliary heat exchanger to simultaneously produce a vapor and a residual, heavier-component-enriched liquid: "The liquid 33 originating from the bottom of the column is expanded in a valve 31 up to a pressure equivalent to the triple point of the carbon dioxide that it contains. The liquid is then sent to the shell of the second exchanger 35 where it is partially vaporized. The gas 37 formed is heated in the first exchanger 9..." (¶ [0064]; Fig. 1). Briglia explains why the vaporization is deliberately left partial: "the impurities optionally present in the liquid CO2 vaporized will be discharged from the exchanger: either in the gas phase for the lightest impurities; or in a liquid purge for the heaviest impurities" (¶ [0053]), and "this liquid purge will be discharged from the exchanger" (¶ [0056]) — the underlying purpose being to prevent formation of a solid, frozen phase of the heavier component that could block and damage the heat exchanger: "this solid phase, which may appear upon a fluctuation of the pressure of the vaporized gas... may block the exchanger and damage it" (¶¶ [0009]-[0010]).
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 modified Murino vaporization of the bottom-liquid-derived stream to be only partial, as taught by Briglia, so as to produce the second gas together with a residual liquid enriched in the heavier component, in order to prevent formation of a solid/frozen phase of the heavier component (e.g., NOx) that could block and damage the heat exchanger. One of ordinary skill would have been motivated to make this modification because Murino's own process is directed to removing and concentrating an NOx-type heavier-than-CO2 impurity that presents an analogous freezing/solidification risk when concentrated in a liquid CO2 stream at low temperature, such that applying Briglia's known partial-vaporization/liquid-purge technique to Murino's bottom-liquid vaporization step would have yielded predictable results with a reasonable expectation of success.
In regard to claim 7, the modified Murino teaches the process of claim 1, including an auxiliary heat exchanger (E2) used to at least partially vaporize the second liquid to produce the second gas, as set forth above. The modified Murino does not expressly teach that at least part of the bottom liquid of the scrubber column is also partially vaporized in the auxiliary heat exchanger.
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 modified Murino’s process such that at least part of the bottom liquid of the scrubber column (Murino's column N, liquid 25) is likewise sent to, and at least partially vaporized in, the auxiliary heat exchanger, as taught by Briglia's technique of routing a heavier-component-bearing liquid to a shared vaporization step in the cold box, in order to recover the refrigeration value of that liquid rather than losing it (Briglia, ¶ [0072]; Fig. 3). One of ordinary skill would have been motivated to make this modification because Murino's own column-N bottom liquid (liquid 25) is, like Briglia's purge liquid, a CO2-bearing liquid enriched in a heavier-than-CO2 impurity intended for removal from the cold box, such that applying Briglia's known technique of routing such a liquid to a shared vaporization step would have yielded predictable results with a reasonable expectation of success.
In regard to claim 8, the modified Murino teaches the process of claim 6, including part of the bottom liquid of the distillation column being partially vaporized in the auxiliary heat exchanger to produce the second gas and a residual liquid enriched in the heavier component, as set forth above.
Murino does not expressly teach that the bottom liquid of the scrubber column is expanded and then mixed with the bottom-liquid-derived stream of the distillation column upstream of the auxiliary heat exchanger, with the resulting mixture partially vaporized to form the second gas and the liquid enriched in the heavier component.
However, Briglia teaches that a carbon-dioxide-rich liquid taken from the bottom of a column and destined for the auxiliary/second heat exchanger is first expanded in a valve to reduce its pressure ("[t]he liquid 33 originating from the bottom of the column is expanded in a valve 31... The liquid is then sent to the shell of the second exchanger 35..." (¶ [0064]; Fig. 1)), and separately teaches mixing a pressurized liquid purge with another CO2-rich liquid upstream of a shared vaporization step, the resulting mixture then being vaporized ("the purge liquid 41 is pressurized in a pump P3 up to a higher pressure at which the CO2, produced by the partial condensation(s) and/or the distillation, is vaporized. The purge 41 is then mixed with this liquid CO2 29 and it is vaporized in the higher pressure flow" (¶ [0072]; Fig. 3)).
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 process of Murino such that the bottom liquid of the scrubber column (Murino's column N) is expanded, per Briglia's teaching of expanding a column-bottoms liquid before sending it to the auxiliary heat exchanger (¶ [0064]; Fig. 1), and then mixed with the bottom-liquid-derived stream of the distillation column upstream of the auxiliary heat exchanger, per Briglia's stream-mixing teaching (¶ [0072]; Fig. 3) - with the resulting mixture partially vaporized in the auxiliary heat exchanger to form the second gas and a liquid enriched in the heavier component, consistent with the partial-vaporization mechanism of ¶¶ [0009]-[0010], [0053], and [0056] (Fig. 1) already discussed in the rejection of claim 6 above.
In regard to claim 14, the modified Murino teaches the process of claim 1, wherein Murino further teaches the bottom liquid (liquid 25) of the scrubber column (column N) is vaporized in the heat exchanger (E1) ("Liquid 25... is drawn from the tank of column N. Liquid 25 is heated in the exchanger E") (¶ 0062; Fig. 3).
The modified Murino does not expressly teach vaporizing this bottom liquid in a heat exchanger other than the first heat exchanger, by indirect heat exchange with an external fluid.
However, Briglia teaches vaporizing a liquid purge removed from an analogous low-temperature CO2 cold box in a heat exchanger other than the (first, main) cold-box heat exchanger, by indirect heat exchange with an external fluid, specifically to recover the purge's refrigeration value outside the main heat exchanger: "In FIG. 4, the purge flow 41 is vaporized outside of the cold box in an exchanger E4 in order to produce iced water 55" (¶ [0073]; Fig. 4); see also claim 25 ("a purge liquid from the second exchanger is vaporized in order to provide frigories to the process").
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 modified Murino’s process to vaporize the bottom liquid of the scrubber column in a heat exchanger other than the first heat exchanger, by indirect heat exchange with an external fluid such as water, as taught by Briglia, in order to recover the refrigeration value of the heavier-component-enriched purge liquid outside the main cold-box heat exchanger — for example to produce iced/chilled water for other plant use — rather than losing that refrigeration value or burdening the main heat exchanger with an additional pass.
Claim(s) 10 and 11 are rejected under 35 U.S.C. 103 as being unpatentable over Murino and White as applied to claim 1 above, and further in view of Beasse et al. (US 2016/0313058 A1).
In regard to claim 10, the modified Murino teaches the process of claim 1, including cooling of the compressed second gas in the heat exchanger prior to sending it to the bottom of the scrubber column, as set forth in the rejection of claim 1 above. Neither Murino nor White expressly discloses cooling the compressed second gas specifically to a temperature within 5°C of its dew point.
However, Beasse teaches, in a closely analogous process for separating NO2 from a CO2 and NO2-containing fluid via a rectifying ("De-NOx") column, cooling a compressed CO2/NOx-bearing gas stream to a biphasic condition — i.e., to a temperature at or immediately below its dew point, immediately before feeding the resulting stream to the rectifying column that separates an NOx-enriched liquid from a CO2-enriched vapor: "Dried, compressed flue gas stream 133 is cooled and at least partially condensed at multi-fluid heat exchanger 135" (¶ 0064; Fig. 3); "the liquid or biphasic flue gas stream 137 is fed to rectifying (also known as De-NOx) column 139... The pressure in the De NOx column is typically about 25 bar abs where the inlet gas temperature is about −19° C." (¶ 0065; Fig. 3). Beasse further demonstrates that a process stream can be deliberately held at its dew point, rather than substantially above or below it, immediately before being fed to a column: "resultant stream 198 is superheated while stream 200 remains at its dewpoint and is fed to stripping column 186 for providing the necessary heat to the column" (¶ 0072; Fig. 3).
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 cooled the compressed second gas of the modified Murino’s process to a temperature within 5°C of its dew point, as taught by Beasse's practice of cooling an analogous CO2/NOx-bearing stream to a biphasic, near-dew-point condition immediately before feeding a rectifying column that separates a heavier NOx component from the CO2, in order to promote the vapor-liquid contacting needed for that column's separation while keeping the feed predominantly in the vapor phase required for delivery to the bottom of the column.
In regard to claim 11, the modified Murino teaches the process of claim 1, including cooling of the compressed second gas in the heat exchanger prior to sending it to the bottom of the scrubber column, as set forth in the rejection of claim 1 above. Neither Murino nor White expressly discloses cooling the compressed second gas to a temperature between its dew point and its dew point +25°C.
However, Beasse teaches, in a closely analogous process for separating NO2 from a CO2 and NO2-containing fluid via a rectifying ("De-NOx") column, cooling a compressed CO2/NOx-bearing gas stream to a biphasic condition - i.e., to a temperature at or immediately below its dew point, immediately before feeding the resulting stream to the rectifying column that separates an NOx-enriched liquid from a CO2-enriched vapor: "Dried, compressed flue gas stream 133 is cooled and at least partially condensed at multi-fluid heat exchanger 135" (¶ 0064; Fig. 3); "[t]he liquid or biphasic flue gas stream 137 is fed to rectifying (also known as De-NOx) column 139... The pressure in the De NOx column is typically about 25 bar abs where the inlet gas temperature is about −19° C." (¶ 0065; Fig. 3). Beasse further demonstrates that a process stream can be deliberately held at its dew point, rather than substantially above or below it, immediately before being fed to a column: "resultant stream 198 is superheated while stream 200 remains at its dewpoint and is fed to stripping column 186 for providing the necessary heat to the column" (¶ 0072; Fig. 3).
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 cooled the compressed second gas of the modified Murino’s process to a temperature between its dew point and its dew point +25°C, as taught by Beasse's practice of cooling an analogous CO2/NOx-bearing stream to a biphasic, near-dew-point condition immediately before feeding a rectifying column that separates a heavier NOx component from the CO2, in order to promote the vapor-liquid contacting needed for that column's separation while keeping the feed predominantly in the vapor phase required for delivery to the bottom of the column. One of ordinary skill would have been motivated to select a margin within this broader range as a routine optimization of the near-dew-point condition Beasse demonstrates is effective for feeding this class of CO2/NOx rectifying column, particularly since Murino's own process already cools the analogous feed stream to column N in the same multi-stream heat exchanger used to condense the other process streams passing through it (Murino, ¶¶ 0054, 0058; Fig. 3). This rejection is made without prejudice to the indefiniteness issue identified in the rejection of claim 11 under 35 U.S.C. § 112(b) above, and treats "cooled... to below a temperature... between the dew point and the dew point +25°C" as reciting an upper cooling limit of dew point +25°C.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to WEBESHET MENGESHA whose telephone number is (571)270-1793. The examiner can normally be reached Mon-Thurs 7-4, alternate Fridays, EST. 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.
/W.M/Examiner, Art Unit 3763
/FRANTZ F JULES/Supervisory Patent Examiner, Art Unit 3763
