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 .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 01/14/2026 has been entered.
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.
This application includes one or more claim limitations that do not use the word “means,” but are nonetheless being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, because the claim limitation(s) uses a generic placeholder that is coupled with functional language without reciting sufficient structure to perform the recited function and the generic placeholder is not preceded by a structural modifier. Such claim limitation(s) is/are:
“a cooling assembly” in claim 1, 9 and 12 is understood to be any art recognized heat exchanger;
“a volumetric affecting device” in claim 1, 9 and 12 is understood to be a turbo-expander or a condensing turbine (see ¶ 0014, 0019 of the specification);
Because this/these claim limitation(s) is/are being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, it/they is/are being interpreted to cover the corresponding structure described in the specification as performing the claimed function, and equivalents thereof.
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 1-2 and 4-20 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 enablement requirement. The claim(s) contains subject matter which was not described in the specification in such a way as to enable one skilled in the art to which it pertains, or with which it is most nearly connected, to make and/or use the invention.
Claims 1 and 9 each recite “a volumetric affecting device fluidly coupled to the cooling assembly to condense the carbon dioxide from the stream into a solid form by work extraction and in a manner facilitating a discouraging of surface accretion within the system.” Claim 12 recites “solidifying carbon dioxide from the stream with a volumetric affecting device in a manner facilitating a discouraging to surface accretion within the system.”
The enablement inquiry asks whether, based on the specification's disclosure, one skilled in the art could make and use the full scope of the claimed invention without undue experimentation. Wands factors relevant to this inquiry include: (1) the quantity of experimentation necessary; (2) the amount of direction or guidance presented in the specification; (3) the presence or absence of working examples; (4) the nature of the invention; (5) the state of the prior art; (6) the relative skill of those in the art; (7) the predictability or unpredictability of the art; and (8) the breadth of the claims. In re Wands, 858 F.2d 731, 737 (Fed. Cir. 1988); MPEP § 2164.01. The Examiner applies each Wands factor below.
Wands Factor (1): Quantity of Experimentation Necessary. The specification provides no working examples, no experimental data, no prophetic examples, and no design criteria by which a practitioner could verify that a given 'volumetric affecting device' achieves 'discouraging of surface accretion within the system.' The specification describes the functional result at a high level (¶ 0014) but provides no structural, operational, or experimental guidance to achieve that result for any device type other than the turbo-expander. For positive-displacement mechanisms — which claim 2 encompasses — the specification offers no guidance whatsoever on how surface accretion is discouraged by such devices. The practitioner would need to conduct substantial experimental investigation to determine what device configurations, operating pressures, expansion ratios, surface temperatures, surface treatments, and flow geometries achieve the claimed surface accretion discouragement across the full range of devices encompassed by the claims. This factor weighs against enablement.
Wands Factor (2): Amount of Direction or Guidance in the Specification. The specification provides no structural parameters, operational conditions, pressure ratios, flow velocities, or temperature differentials required to achieve 'discouraging of surface accretion.' The closest the specification comes is paragraph 0019's statement that moving boundary surfaces of the device 'will actually be warmer than the primary stream,' but this is a qualitative characterization, not a design criterion. No guidance is provided on: how much warmer the surfaces must be; what happens when this temperature differential is insufficient; how to maintain this differential across varying inlet conditions; or how positive-displacement mechanisms satisfy this condition given their different thermodynamic operating profiles. This factor weighs against enablement.
Wands Factor (3): Presence or Absence of Working Examples. The specification contains no working examples, no experimental results, and no prophetic examples demonstrating that any specific device configuration achieves the claimed discouragement of surface accretion. The absence of any working example across the full breadth of the claimed 'volumetric affecting device' further supports a finding of non-enablement. This factor weighs against enablement.
Wands Factor (4): Nature of the Invention. The invention involves cryogenic thermodynamic processes in which solid CO₂ formation occurs at temperatures below approximately –56.6° C. and at specific pressure conditions. The behavior of solid CO₂ in the context of surface deposition is a complex function of nucleation kinetics, surface energy, flow dynamics, and device geometry — not a simple mechanical result that follows predictably from any volumetric expansion. The nature of the invention as involving complex cryogenic phase-change phenomena weighs against a finding of easy enablement across the full claim scope.
Wands Factor (5): State of the Prior Art. The prior art (including Lissianski, Lockwood, and Reddy) demonstrates that preventing solid CO₂ surface deposition in cryogenic systems was a recognized technical challenge requiring specific structural solutions — e.g., Lissianski's disclosure of non-stick coatings and heated components (¶ 0047–0049), and Lockwood's disclosure of surface polishing and special coatings to limit heterogeneous nucleation (¶ 0037–0038 of Lockwood). The state of the art therefore confirms that 'discouraging surface accretion' is not a trivially achievable result from any volumetric device, but rather a technically challenging outcome requiring purposeful design. This factor weighs against enablement.
Wands Factor (6): Relative Skill of Those in the Art. The field of cryogenic gas processing requires highly specialized engineering expertise. One of ordinary skill in this art would understand the complexity of solid CO₂ formation and deposition but would not, without guidance from the specification, be able to determine what structural features of a broadly-claimed 'volumetric affecting device' achieve 'discouraging of surface accretion' across the range of device types encompassed by the claims. The high level of skill required in this complex technical field does not substitute for missing enabling disclosure. This factor is neutral to slightly against enablement.
Wands Factor (7): Predictability or Unpredictability of the Art. Cryogenic phase-change processes, particularly those involving solid CO₂ formation, are recognized in the art as relatively unpredictable — outcomes depend sensitively on inlet gas composition, pressure, temperature, flow geometry, surface conditions, and expansion dynamics. The prior art's express disclosure of specific anti-accretion features (Lissianski ¶ 0047–0049; Lockwood ¶ 0037–0038) confirms this unpredictability. This factor weighs against enablement.
Wands Factor (8): Breadth of the Claims. The claims as amended are broad. The term 'volumetric affecting device,' under BRI, encompasses turbo-expanders, condensing turbines, positive-displacement pistons, Venturi expanders, and any other device operating on volumetric expansion principles. The specification provides enabling guidance only for the turbo-expander embodiment and, by implication, a condensing turbine. The enabling disclosure does not extend across the full breadth of the claimed device types, particularly positive-displacement mechanisms. This factor weighs strongly against enablement.
On balance, application of the Wands factors establishes that the specification does not enable one of ordinary skill in the art to make and use the full scope of the claimed invention without undue experimentation. The claim broadly encompasses any volumetric affecting device that operates in a manner facilitating discouragement of surface accretion, but the specification provides structural and operational guidance only for a turbo-expander and, by implication, a condensing turbine, without working examples, design criteria, or operational parameters sufficient to enable the full claim scope. Stating a desired functional outcome without corresponding enabling disclosure does not satisfy § 112(a). See Sitrick v. Dreamworks, LLC, 516 F.3d 993, 999 (Fed. Cir. 2008); Auto. Techs. Int'l, Inc. v. BMW of N. Am., Inc., 501 F.3d 1274, 1283 (Fed. Cir. 2007); MPEP §§ 2164.01(a), 2164.04.
Claims 4–8, 10–11, and 13–20 are rejected under § 112(a) for dependence upon a rejected base claim.
Claim Interpretation Under the Broadest Reasonable Interpretation Standard
Under BRI, this functional limitation requires that the volumetric affecting device operate in a manner that tends to reduce, inhibit, or avoid the accumulation of solid CO₂ on internal surfaces of the system, as compared to surface-cooling-based condensation approaches. The specification at paragraph 0014 explains the mechanism: because the device achieves condensation 'without reliance on a cooling surface,' 'condensation or accretion of carbon dioxide is not promoted at system surfaces.' Paragraph 0019 further explains that 'the boundary surfaces of the moving portions of the work extraction mechanism 185 will actually be warmer than the primary stream that is being cooled,' so accretion at such surfaces is discouraged. Under this BRI, the limitation is met when the device's inherent mode of volumetric operation results in CO₂ solidifying in the gas volume rather than on fixed cold system surfaces, regardless of whether a prior art reference uses the words 'surface accretion' or 'discouraging.' This interpretation is applied in the prior art analysis below.
“Volumetric affecting device”
The specification does not define 'volumetric affecting device' as an established term of art in the cryogenic gas processing field. Paragraph 0014 states that 'it is the work extraction mechanism 185, such as a turbo-expander, that presents a volumetric effect on the received gas stream to cool and condense without reliance on a cooling surface to achieve the cooling and condensation.' Paragraph 0019 further states that 'the work extraction mechanism 185 may constitute a dynamic working device such as a condensing turbine' or 'a positive displacement mechanism such as a piston or other volumetric affecting device.' Reading these disclosures together and in light of the full specification, the term 'volumetric affecting device' under BRI encompasses any device that: (1) acts upon a received gas stream through a volume-changing, work-extracting, or pressure-reducing mechanism as opposed to heat transfer through a static cooled wall or surface; and (2) causes or facilitates condensation or solidification of CO₂ from the gas stream as a result of that volumetric action. This encompasses, at minimum, turbo-expanders, condensing turbines, positive-displacement pistons, Venturi-based expanders, and other near-isentropic expansion devices. The Examiner applies this BRI consistently throughout the analysis below.
“In a manner facilitating a discouraging of surface accretion within the system”
Under BRI, this functional limitation requires that the volumetric affecting device operate in a manner that tends to reduce, inhibit, or avoid the accumulation of solid CO₂ on internal surfaces of the system, as compared to surface-cooling-based condensation approaches. The specification at paragraph 0014 explains the mechanism: because the device achieves condensation 'without reliance on a cooling surface,' 'condensation or accretion of carbon dioxide is not promoted at system surfaces.' Paragraph 0019 further explains that 'the boundary surfaces of the moving portions of the work extraction mechanism 185 will actually be warmer than the primary stream that is being cooled,' so accretion at such surfaces is discouraged. Under this BRI, the limitation is met when the device's inherent mode of volumetric operation results in CO₂ solidifying in the gas volume rather than on fixed cold system surfaces — regardless of whether a prior art reference uses the words 'surface accretion' or 'discouraging.' This interpretation is applied in the prior art analysis below.
Preliminary Note; Inherency Analysis for the Surface Accretion Limitation as Applied to Lissianski
Applicant argues that Lissianski does not teach a 'volumetric affecting device' operating 'in a manner facilitating a discouraging of surface accretion.' The Examiner disagrees for two independent reasons, either of which is sufficient to establish anticipation of this limitation.
First, under inherency: the instant application's own specification explains, at paragraph 0014, that the reason volumetric expansion devices discourage surface accretion is that they condense CO₂ 'without reliance on a cooling surface' — the CO₂ solidifies in the gas volume through the expansion process itself, not by contact with a cold wall. This physical mechanism is a direct and necessary consequence of volumetric expansion-based CO₂ condensation. Lissianski's multi-phase turbo expander 30 operates by exactly this physical mechanism: the cooled compressed gas stream (32) is expanded through rotating components (rotor 74) causing work extraction and adiabatic cooling, resulting in CO₂ solidifying as part of an LNG/ice/solid CO₂ slurry within the flowing gas stream (¶ 0029, 0040–0045; Figs. 1–4). The solid CO₂ does not form by deposition onto fixed cooled walls — it forms in the gas volume by the volumetric expansion process. Because Lissianski's turbo expander necessarily operates by the same physical mechanism that the applicant's specification identifies as giving rise to discouragement of surface accretion, that functional result is inherent in Lissianski's disclosure. The Examiner is not required to find the words 'surface accretion' in the prior art to establish inherent anticipation of a functional limitation that necessarily results from the disclosed structure operating in its described manner. See In re Cruciferous Sprout Litig., 301 F.3d at 1349.
Second, independently, Lissianski provides express affirmative disclosure of structural features of the turbo expander 30 specifically directed to preventing solid CO₂ adhesion at device surfaces: non-stick coatings (92) on rotating components (74) configured to preclude adhesion of solid CO₂ to rotating surfaces (94) (¶ 0047); heated stationary components (76) configured to preclude adhesion of solid CO₂ to stationary surfaces (96) (¶ 0047–0048); and electrical heating elements and gas flow channels in stationary blades (80) for the same purpose (¶ 0049). These express structural features confirm that Lissianski's turbo expander 30 is designed and operated in a manner that affirmatively discourages surface accretion of solid CO₂ within the device and the system. This is direct, not merely inherent, anticipation of the surface accretion limitation.
Claim Rejections - 35 USC § 102
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 the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
Claim(s) 1-2, 5, 8 and 12-16 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Lissianski et al. (US 2015/0033792 A1).
In regard to claim 1, Lissianski teaches a cryogenic-based carbon dioxide capture system comprising:
an exhaust line for channeling a gas stream (16), the gas stream (16) having an initial mean temperature (the initial temperature of stream 16 as introduced into system 10, ¶ 0024) and including carbon dioxide gas (¶ 0018; fig. 1,2);
a cooling assembly (cooling stage 200 comprising heat exchangers 29 and 24) fluidly coupled to the exhaust line (16) to bring a temperature of the stream (16/21) down to an initial cooling temperature between the initial mean temperature and a de-sublimation temperature for the carbon dioxide gas in the stream (¶ 0025-0028, 0039; fig. 1, 2; Lissianski discloses heat exchanger 24 pre-cools the low-moisture compressed NG stream 21 to approximately –40° C. (¶ 0028), a temperature above the CO₂ de-sublimation temperature under the operating conditions of the system, thereby bringing the stream to an initial cooling temperature between the initial mean temperature and the de-sublimation temperature).
“a volumetric affecting device (30) fluidly coupled to the cooling assembly (24) to condense the carbon dioxide from the stream into a solid form by work extraction and in a manner facilitating a discouraging of surface accretion within the system” Lissianski discloses multi-phase turbo expander 30 in fluid communication with heat exchanger 24 via cooled compressed discharge stream 32. Turbo expander 30 expands stream 32 through rotating components (rotor 74, blades 80/82), extracting work (via common shaft 36 to compressor 22) and generating expanded exhaust stream 34 comprising a mixture of CH₄ vapor and LNG/ice/solid CO₂ slurry - i.e., CO₂ is condensed into solid form by the work extraction process (¶ 0029, 0040-0045; Figs. 1-4). Turbo expander 30 is a 'volumetric affecting device' under BRI as it acts upon the gas stream through a volume-changing work-extracting mechanism without reliance on a fixed cooling surface. The surface accretion limitation is met both inherently and by express disclosure as set forth in the Preliminary note above (¶ 0047-0049).
In regard to claim 2, Lissianski teaches a cryogenic-based carbon dioxide capture system of claim 1, wherein the volumetric affecting device (turbo expander 30) is one of a dynamic mechanism — turbo expander 30 is a radial, axial, or mixed-flow turbomachine constituting a dynamic rotary mechanism (¶ 0040) — and a positive displacement mechanism, as Lissianski at paragraph 0029 describes the turbo expander in the context of work extraction mechanisms that include both dynamic and positive-displacement options.
In regard to claim 5, Lissianski teaches a cryogenic-based carbon dioxide capture system of claim 1, wherein the cooling assembly comprises one of an air cooler and a chiller (air cooler 29 and heat exchanger 24, which collectively constitute one of an air cooler and a chiller as recited in ¶ 0028).
In regard to claim 8, Lissianski teaches a cryogenic-based carbon dioxide capture system of claim 1, wherein Lissianski teaches separator 38 coupled to turbo expander 30, which separates LNG/ice/CO₂ slurry stream 42 from vapor stream 40 (comprised substantially of CH₄). Stream 40 constitutes a substantially carbon-free emission, and solid CO₂ in stream 42 is diverted for management (¶ 0031–0034, 0037–0038, 0045; Figs. 1, 2).
In regard to claim 12, Lissianski teaches method of cryogenic-based carbon capture from an exhaust gas stream in a system, the method comprising:
channeling the exhaust gas stream (16/21) with an initial mean temperature to a cooling assembly (cooling stage 200 comprises heat exchangers 29, 24) of the system to bring a temperature thereof down to an initial cooling temperature between the initial mean temperature and a de-sublimation temperature for the carbon dioxide gas in the stream (¶ 0025–0028, 0039; Figs. 1, 2: Lissianski channels stream 16/21 through cooling stage 200 (heat exchangers 29, 24) to bring the temperature to approximately –40° C., above the CO₂ de-sublimation temperature).
solidifying carbon dioxide from the stream with a volumetric affecting device in a manner facilitating a discouraging to surface accretion within the system (¶ 0029, 0045, 0047–0049; Figs. 1–4: Lissianski's turbo expander 30 solidifies CO₂ from the stream by volumetric work extraction, generating solid CO₂ as part of the LNG/ice/solid CO₂ slurry in expanded stream 34 (¶ 0029, 0045; Figs. 1–4). The surface accretion limitation is met both inherently and by express disclosure as set forth in the preliminary note above (¶ 0047–0049).
In regard to claim 13, Lissianski teaches the method of claim 12, further comprising compressing the stream (stream 16) at a compressor (compressor 26) in advance of the channeling to the cooling assembly (29) (¶ 0025–0027; Figs. 1, 2).
In regard to claim 14, Lissianski teaches the method of claim 13, wherein the initial cooling temperature of the stream is achieved with one of an air cooler (air cooler 29) and/or a chiller (chiller-type heat exchanger 24) (¶ 0028).
In regard to claim 15, Lissianski teaches the method of claim 13 wherein the compressor (26) is a first compressor (see fig. 1, 2) the method further comprises directing an emission of the stream (stream 40/501) from a separator (38) coupled to the volumetric affecting device (30) to a second compressor (44) for one of facilitating cooling at the cooling assembly (29) and facilitating cooling at another cooling assembly (24) fluidly coupled to the volumetric affecting device (30) (¶ 0031–0034; Figs. 1, 2).
In regard to claim 16, Lissianski teaches the method of claim 15 wherein the second compressor (44/46) is provided in a unitary form with t the volumetric affecting device (turbo expander 30) (see ¶ 0029; fig. 1, 2).
Claim(s) 9 and 11 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Lockwood et al. (US 2011/0302955 A1).
In regard to claim 9, Lockwood teaches an industrial site complex comprising (¶ 0053; Figures 1 and 8–13):
a process facility for producing an exhaust gas (24) at an initial mean temperature (initial temperature of 24), the gas including carbon dioxide (¶ 0016, 0053, 0071; Lockwood's industrial site comprises an industrial process unit (e.g., a boiler or combustion plant, Figs. 8–9) that produces flue gas (fluid 24/40) containing CO₂ at an initial mean temperature).
a cryogenic-based carbon dioxide capture system fluidly coupled to the process facility for receiving the exhaust gas (Fig. 1; ¶ 0070–0072; Lockwood's CO₂ capture system is fluidly connected to the industrial site process facility and receives the exhaust gas stream (fluid 24/40) as its process input);
a cooling assembly (heat exchangers 109 and 111) to bring a temperature of the stream (40) down to an initial cooling temperature between the initial mean temperature and a de-sublimation temperature for the carbon dioxide gas in the stream (¶ 0077–0078; Figs. 1, 6: Lockwood discloses heat exchangers 109 and 111 that cool the dried process fluid 40 to a temperature close to but above the CO₂ solidification temperature — expressly stated as approximately –100° C. for a stream containing approximately 15% CO₂ by volume at near-atmospheric pressure, which is above the CO₂ cryo-condensation temperature under those conditions. This is an initial cooling temperature between the initial mean temperature of the exhaust gas and the de-sublimation temperature for CO₂);
a volumetric affecting device (expansion/Venturi device 702) fluidly coupled to the cooling assembly (heat exchangers 109 and 111) to condense the carbon dioxide from the stream into a solid form by work extraction and in a manner facilitating a discouraging of surface accretion within the system (Fig. 6; ¶ 0126–0131). Lockwood discloses expansion/Venturi device 702 in fluid communication with the cooling assemblies (109, 111). expansion/Venturi Device 702 operates by causing the process fluid 701 to rotate via fixed vanes 717 and then expanding it through Venturi restriction 718, producing solid CO₂ particles (¶ 0127–0128). This is a volumetric affecting device under BRI: it acts on the gas stream through a volume-changing, work-extracting pressure-reduction mechanism without reliance on a fixed cold surface. CO₂ is condensed into solid form by this volumetric expansion process (¶ 0128–0130). The surface accretion limitation is met both inherently and by express disclosure as set forth in the preliminary note below (¶ 0037–0038, 0127–0128).
In regard to claim 11, Lockwood teaches the industrial site complex of claim 9 further comprising a management location (management and transport infrastructure for solid CO₂) for obtaining the solid form of the carbon dioxide (62) for one of transport and local use (¶ 0095, 0178; Fig. 1).
Preliminary Note: Inherency Analysis for the Surface Accretion Limitation as Applied to Lockwood
Lockwood's expansion/Venturi device 702 (Fig. 6; ¶ 0126–0131) operates by imparting rotational movement to the gas stream 701 through fixed vanes 717, then expanding the rotating fluid through a Venturi restriction 718, causing the fluid to cool below the CO₂ cryo-condensation temperature and producing solid CO₂ particles (¶ 0127–0128). The solid CO₂ particles are recovered at the periphery of the rotating flow by centrifugal effect (¶ 0128). This device operates by volumetric expansion through the Venturi restriction and rotational flow dynamics — cooling is achieved through the pressure-volume change and kinetic energy conversion, not through heat transfer to a static cooled surface. Under the physical rationale set forth in the instant application's specification (¶ 0014), this mode of operation inherently discourages surface accretion because CO₂ solidifies in the flowing gas volume and is centrifugally collected at the flow periphery, not deposited onto system wall surfaces. Additionally, Lockwood independently and expressly confirms at paragraphs 0037–0038 that expansion turbine designs for cryogenic CO₂ capture require surface polishing, special coatings, and surface heating specifically to limit heterogeneous nucleation of solid CO₂ on turbine surfaces — confirming that volumetric expansion-based devices are recognized in the art as operating in a manner that discourages surface accretion compared to surface-cooled alternatives. These paragraphs constitute express disclosure of the surface accretion discouragement concept in the context of volumetric expansion devices.
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.
Claim(s) 4, 6, 7, 17 and 18 are rejected under 35 U.S.C. 103 as being unpatentable over Lissianski et al. (US 2015/0033792 A1) in view of Reddy et al. (US 2016/0327337 A1).
In regard to claim 4, Lissianski teaches the cryogenic-based carbon dioxide capture system of claim 1 further comprising a compressor (26) coupled to the exhaust gas line for compressing stream (16) in advance of reaching the cooling assembly (29, 24) (¶ 0025–0028, 0036; Figs. 1, 2). Lissianski does not explicitly teach compressing the stream to between about 3 bara and about 10 bara.
Reddy teaches a cryogenic CO₂ capture configuration wherein flue gas (101) is compressed by blower BL-101 to generate a pressurized flue gas stream (102) at a pressure of 50–150 psia (approximately 3.45 bara to 10.3 bara), which is then pre-cooled in exchanger E-101 before downstream CO₂ desublimation (¶ 0027; Figs. 1A, 2A). Reddy therefore establishes that 3 bara to approximately 10 bara is a known and conventional upstream compression range for cryogenic CO₂ capture systems applied to flue gases.
Therefore, it would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention to operate the compressor of Lissianski within the pressure range of about 3 bara to about 10 bara, in view of the teaching of Reddy, in order to provide favorable CO₂ partial pressure conditions for downstream desublimation, permits reasonable equipment sizing for the heat exchangers and expansion device, and is consistent with energy-efficient operation of cryogenic CO₂ capture systems as confirmed by Reddy's disclosure. One of ordinary skill would have selected a compression pressure within this established range with a reasonable expectation of success in achieving the desired downstream CO₂ capture performance.
In regard to claim 6, Lissianski teaches the cryogenic-based carbon dioxide capture system of claim 1 with first and second cooling assemblies (heat exchangers 29, 24) and moisture removal device (12). Lissianski does not explicitly teach: (a) that the initial cooling temperature is above 0° C.; (b) a mechanical separator dedicated to water removal positioned between the first and second cooling stages; or (c) a dryer between the first and second cooling stages.
Reddy teaches a staged cryogenic CO₂ capture process wherein: (i) pressurized flue gas stream (102) enters first precooler E-101 and is cooled to form stream (103) at a temperature above the freezing point of water -expressly above 0° C. (¶ 0024); (ii) stream (103) enters dryer D-101, which removes condensed liquid water (stream 105) by mechanical separation and also dries the gas stream - Reddy states D-101 'may be a glycol or other suitable gas dryer,' establishing that D-101 provides both a mechanical separator function and a drying function; and (iii) dry cooled flue gas (104) then enters second precooler E-102 to cool to below 0° C. and above the CO₂ desublimation temperature (¶ 0024; Figs. 1A, 2A). Reddy's unit D-101 thus teaches both the mechanical separator and the dryer of claim 6, positioned between the first and second cooling stages as claimed.
Therefore, it would have been obvious to a person of ordinary skill in the art before the effective filing date to modify the system of Lissianski by: (1) setting the first cooling stage temperature above 0° C.; and (2) positioning a combined mechanical separator and dryer unit, as taught by Reddy's D-101, between the first and second cooling stages; in view of the teachings of Reddy, by staging the cooling process so that the first stage operates above 0° C. allows liquid water to be removed efficiently as a liquid before the gas encounters the colder second stage and downstream cryogenic equipment. Water that is not removed before the second stage will freeze in the second-stage heat exchangers and downstream equipment, causing fouling, plugging, and forced system shutdowns. Positioning the drying step between the two cooling stages, as Reddy teaches, exploits the initial cooling to condense water while avoiding ice formation, improving dryer efficiency, and reducing equipment size.
In regard to claim 7, the modified combination of Lissianski in view of Reddy teaches the cryogenic-based carbon dioxide capture system of claim 6 wherein the second cooling assembly is a recuperator (Lissianski's heat exchanger 24) functions as a recuperator, using cold return streams (the cold CH₄ vapor stream 40 recirculated via path 501) to pre-cool the inlet compressed stream, providing recuperative heat exchange (¶ 0028, 0031–0032, 0039; Figs. 1, 2); and the working temperature is between about –80° C. and about –120° C. - Reddy teaches cooling to below 0° C. and above –100° C., more typically above –115° C. at about atmospheric pressure (¶ 0024), a range that overlaps the claimed –80° C. to –120° C. working temperature range. The combination as modified for claim 6 establishes operation in this temperature range.
In regard to claim 17, Lissianski teaches the method of claim 12 including moisture extraction from the exhaust gas stream (16) using moisture removal device (12) upstream of the cooling and compression stages (¶ 0023–0026; Figs. 1, 2). Lissianski does not explicitly teach extracting water at the initial cooling temperature as a distinct method step between the first and second cooling stages.
Reddy teaches extracting water from the pressurized flue gas stream at the initial cooling temperature above 0° C. - dryer D-101 removes liquid water stream 105 from pre-cooled stream 103 at a temperature above the freezing point of water, between the first and second pre-cooling stages (¶ 0024). Therefore, it would have been obvious to a person of ordinary skill to modify the method of Lissianski to extract water at the initial cooling temperature as taught by Reddy, for the same reasons stated in the claim 6 rejection above: removing water in the liquid phase at a temperature just above 0° C., before the gas is cooled further in the second stage, prevents ice formation in downstream cryogenic equipment and improves dryer efficiency.
In regard to claim 18, the modified combination of Lissianski in view of Reddy teaches the method of claim 17 wherein the cooling assembly is a first cooling assembly (29), and the method further comprises cooling the stream to a working temperature between the initial cooling temperature and a de-sublimation temperature for carbon dioxide in the stream at a second cooling assembly (24) in advance of the solidifying of the carbon dioxide (see Lissianski ¶ 0025–0028, 0039; Reddy ¶ 0024, 0036–0037).
Claim 10 is rejected under 35 U.S.C. § 103 as being unpatentable over Lockwood et al. (US 2011/0302955 A1) in view of Kaminsky et al. (US 2021/0063083 A1).
In regard to claim 10, Lockwood teaches the industrial site complex of claim 9. Lockwood discloses that the CO₂-lean gas (stream 46/48) is heated in the system heat exchangers and exits as a residual flow (stream 25/48) after CO₂ capture (¶ 0085, 0095–0100; Figs. 1, 8–9). Lockwood does not explicitly teach a dedicated stack component for release of the exhaust gas to the atmosphere in a substantially carbon-free form as a discrete structural element of the industrial site complex.
Kaminsky teaches a system for processing production gas containing CO₂ wherein a separated primarily-gaseous fluid stream (203) - the CO₂-depleted fraction of the gas following solid CO₂ separation at tank 160 - is used as a cooling fluid for heat exchanger 130 before being consumed at burner 270, described as a flaring device, for atmospheric release (¶ 0033, 0049, 0055; Figs. 2A, 2B, 5). Kaminsky thus teaches the provision of an atmospheric release point - whether a flare stack or exhaust stack - for the CO₂-depleted gas remaining after CO₂ separation.
Therefore, it would have been obvious to a person of ordinary skill in the art before the effective filing date to modify the industrial site complex of Lockwood to include a stack for releasing the substantially carbon-free exhaust gas stream to the atmosphere, in view of the teachings of Kaminsky, in order to provide an atmospheric release point for the CO₂-depleted gas, because (1) an exhaust stack is a standard, universally required component of any industrial combustion site handling flue gases — environmental regulations mandate that treated flue gas be released to atmosphere through a monitored stack; (2) the modification involves simply adding a well-known, standard structural element to Lockwood's existing system at the location where the treated gas exits; and (3) one of ordinary skill in the art would have recognized that without an exhaust stack, Lockwood's system would have no defined outlet for the treated CO₂-lean gas, rendering the system non-functional for its stated environmental purpose.
Claims 19 and 20 are rejected under 35 U.S.C. § 103 as being unpatentable over Lissianski et al. (US 2015/0033792 A1) in view of Baxter et al. (US 2020/0318900 A1).
In regard to claim 19, Lissianski teaches the method of claim 12 including separating solidified carbon dioxide (slurry stream 42, solid stream 54) from the gas stream (¶ 0031, 0034). Lissianski does not explicitly teach: (a) liquifying the separated solidified carbon dioxide after separation; (b) directing the liquified carbon dioxide to a return to the cooling assembly; (c) routing the liquified CO₂ to another cooling assembly coupled to the volumetric affecting device; or (d) routing the liquified CO₂ to a line for extraction.
Baxter teaches a process fluid separation method wherein solid CO₂ product stream (46) is warmed against refrigerant (62) in heat exchanger (18) and pressurized by pump (20), yielding liquid CO₂ product stream (54). The liquid CO₂ stream (54) is then directed across a cooling assembly (heat exchanger 14), where it provides cooling duty for the incoming process fluid stream (40), thereby recovering the refrigeration value of the CO₂ product to improve overall process thermal efficiency (Fig. 3; ¶ 0025–0027). Baxter expressly teaches each of the limitations not disclosed by Lissianski: liquification of separated solid CO₂, and directing the liquified CO₂ to a cooling assembly for heat integration. The routing options recited in claim 19 — return to the cooling assembly, routing to another cooling assembly coupled to the volumetric affecting device, and routing to a line for extraction — are all expressly or by obvious implication taught by Baxter's disclosure of liquid CO₂ management options (¶ 0025–0027, 0034–0035).
Therefore, it would have been obvious to a person of ordinary skill in the art before the effective filing date to modify the method of Lissianski by incorporating Baxter's CO₂ liquification and heat-integration step for the following reasons grounded in KSR: (1) both Lissianski and Baxter operate in the same technical field of cryogenic CO₂ capture and separation from gas streams; (2) liquifying and recycling solid CO₂ as a cooling medium is a well-recognized heat integration technique in cryogenic processing that recovers the latent and sensible heat content of the CO₂ product, directly improving process energy efficiency; (3) the modification involves appending Baxter's downstream CO₂ handling step to Lissianski's upstream solid CO₂ separation step, these are compatible and sequential process steps that a skilled artisan would naturally combine; and (4) the result is predictable: reduced external refrigeration load and improved overall system efficiency, as Baxter expressly demonstrates.
In regard to claim 20, the modified combination of Lissianski in view of Baxter teaches the method of claim 19 wherein the directing is powered by a solid pump selected from the group consisting of: a solid pump that is discrete from the one of the cooling assembly and the other cooling assembly; and a solid pump that is unitary with the one of the cooling assembly and the other cooling assembly. Baxter teaches pump 20 as a discrete pump component structurally separate from heat exchangers 14 and 18 (Fig. 3; ¶ 0025–0027). A pump integrated as a unitary assembly with a cooling assembly — presents a packaging and footprint optimization variant that would have been obvious to one of ordinary skill as a straightforward engineering expedient aimed at reducing system complexity, minimizing fluid connections, and decreasing installation costs, without any unexpected result.
Response to Arguments
Applicant’s arguments with respect to the amended claims have been considered but are moot in view of the new ground(s) of rejection, unless otherwise noted below.
Applicant's remarks and amendments submitted in the Response have been fully considered. The amendments to the independent claims replace the term 'work extraction mechanism' with 'volumetric affecting device' throughout claims 1, 2, 6, 8, 9, 12, 15, 16, 19, and 20. Claim 3 has been cancelled. For the reasons set forth in full above and/or below, the Examiner finds that the amendments and arguments do not overcome the outstanding rejections. The rejections under 35 U.S.C. §§ 112(a), 102(a)(1), and 103 are maintained on independent grounds as further detailed above.
Applicant’s argument (at page 6-7 of the Remarks) state that it is explained. Indeed, the explanations provided in the specification appear to go far beyond what would be required for anyone such as the Examiner skilled in the art.
In response, the examiner respectfully disagrees. The enablement standard is not whether the concept is explained or understandable at a high level, but whether the specification enables one of ordinary skill to make and use the full scope of the claimed invention across the entire range of devices and conditions the claims encompass. See Wands, 858 F.2d at 737. As demonstrated in the Wands factor analysis above, the specification describes the desired functional result and the general operating principle of one specific embodiment (the turbo-expander) but does not provide the structural detail, operational parameters, working examples, or design criteria needed to enable the full breadth of the claimed 'volumetric affecting device', particularly positive-displacement mechanisms, which are expressly recited in claim 2 but receive no enabling guidance in the specification whatsoever. Understanding a concept and being enabled to practice it across the full claim scope are distinct inquiries.
Applicant’s argument (at page 7 of the Remarks) wherein applicant argued that as is understood in the art and detailed at par. 14 and throughout the specification, using a device like an expander presents a volumetric effect on the received gas stream to condense without reliance on a cooling surface to achieve the cooling and condensation. As a result, condensation or accretion of carbon dioxide is not promoted at system surfaces.
In response, the examiner respectfully disagrees. The Examiner acknowledges that paragraph 0014 contains this statement. However, this statement is a general characterization of the functional result for the turbo-expander embodiment. It does not constitute an enabling teaching for the full scope of the claims for the reasons set forth in the Wands factor analysis above. In particular: (a) it does not provide guidance for positive-displacement mechanisms; (b) it does not identify what design or operational parameters ensure the claimed surface accretion discouragement is achieved; and (c) it does not address what happens when operating conditions deviate from the idealized description. A broad functional statement in the specification does not by itself establish enablement of the full claim scope.
Applicant’s argument (at page 7 of the Remarks) that the concept is 'that a gas stream may be taken down from an initial temperature to one that is closer to a de-sublimation temperature but not fully there and then introducing a volumetric affecting device to achieve the solid CO₂ formation' and that this 'accomplishes the final CO₂ solidification' without 'encouragement for ice accumulation at such surfaces.'
In response, the examiner respectfully disagrees. The Examiner notes that this description again pertains to the general operating principle of the claimed approach and is not disputed as a matter of technical concept. The enablement concern is not about understanding the concept; it is about whether the full range of claimed devices — under all operating conditions and configurations encompassed by the claims — are enabled to practice that concept with 'discouraging of surface accretion' as required. That enabling disclosure is not present in the specification for the reasons detailed above.
Applicant’s argument (Remark page 9) that the Examiner has asserted that Lissianski and Lockwood both teach condensing the carbon dioxide from the stream into a solid form by work extraction. The Applicant acknowledges that this is the case and is representative of the prior art as discussed above regarding Applicant's own par. 3. However, the Examiner goes on to say that these references teach in substantial absence of surface accretion within the system (see pp. 6 and 9 of the present Action). Of course, this is not true at all and there is no substantive description of anything of the kind by either reference.
In response, the examiner respectfully disagrees. As set forth in full in the preliminary notes above, the surface accretion limitation is met by Lissianski and Lockwood on two independent grounds: (1) inherency, both references disclose volumetric expansion-based CO₂ condensation devices that necessarily operate by the same physical mechanism that the applicant's own specification identifies as giving rise to discouragement of surface accretion; and (2) express disclosure, Lissianski at paragraphs 0047–0049 explicitly discloses non-stick coatings (92) and heated components specifically designed to prevent solid CO₂ adhesion at turbo expander surfaces, and Lockwood at paragraphs 0037–0038 expressly discloses polished surfaces, special coatings, and surface heating of expansion turbine components to limit heterogeneous nucleation of solid CO₂. Applicant's assertion that 'there is no substantive description of anything of the kind by either reference' is factually incorrect with respect to both references.
Applicant’s argument (Remark page 9) that in prior prosecution the argument was similar in that the deficiencies of the references in terms of these same teachings were supplanted by the Examiner's use of a different 112 rejection. Namely, the Examiner found that the claim language previously presented regarding a substantial absence of surface accretion was indefinite. However, that language has since been amended and that 112 rejection replaced with the one described above regarding enablement.
In response, the examiner respectfully disagrees. The Examiner's current and prior positions are consistent and do not contradict one another. The § 112(b) rejection in the prior Action addressed the previous claim language 'substantial absence of surface accretion' as indefinite. The current § 112(a) rejection addresses the amended language on enablement grounds, a separate inquiry. Neither the prior § 112(b) rejection nor the current § 112(a) rejection is used to discount the surface accretion limitation in the prior art analysis. As stated above, the § 102/§ 103 rejections are maintained on independent grounds: the prior art affirmatively meets the surface accretion limitation through inherency and express disclosure, without any reliance on the § 112 rejections.
Applicant’s argument (Remark page 10) that in both circumstances, the clarifying claim amendment of a volumetric affecting device to avoid surface accretion due to the manner in which it is arranged within the system is simply not taught. For these reasons, the Applicant respectfully requests removal of these 102 rejections to the independent claims 1, 9 and 12 as well as all dependent claims therefrom.
In response, the examiner respectfully disagrees. As demonstrated in the element-by-element mapping above, all limitations of the independent and dependent claims, including the surface accretion limitation, are met by the prior art references on the independent grounds of inherency and express disclosure set forth herein. The § 102 rejections are maintained.
Conclusion
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/W.M/Examiner, Art Unit 3763
/FRANTZ F JULES/Supervisory Patent Examiner, Art Unit 3763
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