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 .
This is a first action on the merits of the application. Claims 1-19 are pending.
Claim Interpretation
“Low-grade heat” (claims 1, 13) is interpreted as heat obtained as waste heat (US 4,982,782, col. 2, lines 44-45).
“High-pressure” and “low-pressure” streams (claims 1, 13) are interpreted as Applicant’s chosen names for the respective streams, so that no particular pressure or pressure range is considered to be implicit in these names.
Claim Objections
Claim 2 is objected to because of the following informality:
Claim 2: The claim includes a superfluous space before the period.
Appropriate correction is required.
Claim Rejections - 35 USC § 112
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 1-19 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: The claim recites, “compressing the hydrogen depleted tail gas stream in a tail gas compressor to form a compressed tail gas stream, or compressing a refrigerant gas stream in a refrigerant gas compressor . . . separating the compressed tail gas stream in a CO2 recovery system.” Since lines 9-10 recite forming the compressed tail gas stream as an alternative, while line 14 recites separating the compressed tail gas stream, which may not exist if the alternative choice of compressing a refrigerant gas stream is taken, there is a discordance within the claim about whether “compressing the hydrogen depleted tail gas stream in a tail gas compressor to form a compressed tail gas stream” is required by the claim, or is merely an alternative, and if it is an alternative, it is not clear whether “separating the compressed tail gas stream” is required. Therefore, the claim is indefinite. For the purposes of examination only, the forming of the compressed tail gas stream is interpreted to be required by the claim.
Claims 2-12 are rejected because of their dependence from claim 1.
Claim 2: The claim recites, “wherein the low-pressure steam stream, or streams (more than one) comprises.” There is insufficient antecedent basis for “the low-pressure steam . . . streams (more than one)” in view of the apparent antecedent of “a low-pressure steam stream.”
Claim 11: The claim recites, “wherein the total amount of power required to operate the tail gas compressor or the refrigerant gas compressor is reduced by 20% or more.” It is unclear what the basis of comparison for the reduction is (e.g., reduced during the process; reduced compared to another process which is not claimed).
Claim 13 is rejected upon the same bases as claims 1 and 11 (i.e., “compressing the hydrogen depleted tail gas stream in a tail gas compressor to form a compressed tail gas stream . . . or compressing a refrigerant gas stream . . . separating the compressed tail gas stream” is unclear because the alternatives separated by “or” are not treated as alternatives within the claim; and the basis of comparison for “the total amount of power to operate the tail gas compressor, or the refrigerant gas compressor, or both being reduced by 20% or more using the power produced by the turbine” is unclear, as it is not explicitly stated).
Claims 14-19 are rejected because of their dependence from claim 13.
Claim 14: The claim recites, “the low-pressure steam stream(s).” In view of the apparent antecedent in claim 13 (“producing a low-pressure steam stream”), there is insufficient antecedent basis for ““the low-pressure steam streams.”
Claim Rejections - 35 USC § 103
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, 3, 6, and 11-12 are rejected under 35 U.S.C. 103 as being unpatentable over Cruz et al. (US 2022/0306464 A1) in view of Hydrogen Energy International Limited (EP2233430A1, hereinafter “HEIL”).
Regarding claim 1, Cruz discloses a process for producing a hydrogen-enriched product and recovering CO2 (Abstract) (i.e., a method of producing a hydrogen-enriched product and recovering CO2) comprising:
providing an effluent stream 445 from a WGS unit 430 comprising hydrogen and CO2 (Fig. 4; [0089]) regarded as a synthesis gas mixture (claim 1), obtained from an ATR/GHR process unit 420 and a WGS unit 430 ([0081]) used for producing the hydrogen (claims 1, 13; [0003]) (i.e., providing a synthesis gas stream comprising hydrogen and carbon dioxide from a hydrogen production process) and from which heat may be recovered ([0082]; claim 13) (i.e., the hydrogen production process producing low-grade heat);
generating steam from the effluent stream (claim 13) (i.e., producing a low-pressure steam stream from the low-grade heat);
separating the effluent stream 445 in a PSA system comprising two PSA units 510, 515 into a low-pressure tail gas stream 465 enriched in CO2 and high-pressure stream 520 comprising substantially all the hydrogen ([0090]), wherein the tail gas stream contains hydrogen ([0038]) (i.e., separating the synthesis gas stream in a hydrogen pressure swing adsorption (PSA) unit into a first high-pressure hydrogen stream enriched in hydrogen and a hydrogen depleted tail gas stream comprising a portion of the hydrogen and the carbon dioxide);
sending the low-pressure tail gas stream 465 enriched in CO2 to compressor 470 to form a low-pressure compressed tail gas stream 475 ([0085]) (i.e., compressing the hydrogen depleted tail gas stream in a tail gas compressor to form a compressed tail gas stream);
separating the low-pressure compressed tail gas stream 475 into a bottoms stream 490 comprising liquid CO2 and an overhead stream 495 in a CO2 recovery unit 480 ([0085]), the overhead stream comprising a portion of the hydrogen ([0042]) (i.e., separating the compressed tail gas stream in a CO2 recovery system into a CO2-enriched product stream and an overhead stream comprising the portion of the hydrogen); and
recovering the liquid CO2 stream ([0015]) (i.e., recovering the CO2-enriched product stream).
However, Cruz does not explicitly disclose introducing the low-pressure steam stream to a turbine to generate power for the tail gas compressor or a refrigerant gas compressor.
HEIL discloses a process for generating hydrogen and carbon dioxide (Abstract) wherein a synthesis gas stream comprising hydrogen and carbon dioxide (col. 15, lines 1-2) is passed to a CO2 removal unit 15 (Fig. 1; [0049]) that may be a PSA unit ([0026]) and separated into a carbon dioxide rich stream 16 and a hydrogen rich stream 17 ([0049]). HEIL teaches that the synthesis gas stream exits a Pox reactor unit 5 and is cooled by a waste heat boiler (steam generator) 9 to produce steam that is used for driving compressors via a stream turbine of an electrical generator ([0047]).
Therefore, before the effective filing date of the claimed invention it would have been obvious to one of ordinary skill in the art to modify the method of Cruz by introducing the low-pressure steam stream to a turbine to generate power for the tail gas compressor as taught by HEIL because (1) Cruz teaches that energy can be recovered from the WGS unit by cooling its effluent to generate steam (Cruz, [0059]); (2) steam from recovered heat can be used for driving compressors via a stream turbine of an electrical generator (HEIL, [0047]); and (3) it would have been obvious to the skilled practitioner of Cruz in view of HEIL that the compressor 470 can be powered by steam from recovered heat.
Regarding claim 3, HEIL teaches that steam is used to drive a compressor via a turbine ([0047]) (i.e., wherein the turbine is a steam turbine).
Regarding claim 6, Cruz teaches that the feed gas can be process streams from new and existing hydrogen production processes such as steam reforming with an optional gas heated reformer, autothermal reforming with an optional gas heated reformer, gasification, or partial oxidation (POX) ([0024]) (i.e., wherein the hydrogen production process comprises a steam reforming unit with an optional gas heated reformer, an autothermal reforming unit with an optional gas heated reformer, a partial oxidation unit, or a gasification unit).
Regarding claim 11, Cruz in view of HEIL does not explicitly disclose that the total amount of power required to operate the tail gas compressor or the refrigerant gas compressor is reduced by 20% or more.
However, recognition by Applicant of an advantage which would flow naturally from following the suggestion of the prior art cannot be the basis for patentability when the differences would otherwise be obvious.” See MPEP 2145(II). Alternatively, it is asserted that, absent evidence to the contrary, one would reasonably expect that the method as taught by Cruz in view of HEIL functions the same as the method recited in claim 11, since Cruz in view of HEIL discloses the same method for producing a hydrogen-enriched product and recovering CO2 as claimed, considering that HEIL teaches the recovery of heat ([0029]) (i.e., power), so it would have been obvious to the practitioner of Cruz in view of HEIL to maximize power recovery or efficiency through the heat recovery. If it is Applicant’s position that this would not be the case: (1) evidence would need to be provided to support Applicant’s position; and (2) it would be the Office’s position that the application contains inadequate disclosure as to how to obtain the claimed reduction in total amount of power with only the claimed steps.
Regarding claim 12, Cruz teaches the production of higher value heat (i.e., increasing a temperature of the low-pressure steam stream) by contacting waste heat with phosphoric acid leading to oligomerization to diphosphoric acid and split off water molecules that condense (i.e., contacting the low-grade heat with a phosphoric acid stream comprising phosphoric acid to oligomerize the phosphoric acid forming a diphosphoric acid stream comprising diphosphoric acid and water; condensing the water); increasing the pressure of the diphosphoric acid stream (i.e., increasing a pressure of the diphosphoric acid stream); evaporating the water with the waste heat which is absorbed by the diphosphoric acid, causing de-oligomerization and hydrolysis to occur resulting in conversion back to phosphoric acid and the production of higher value process heat (i.e., evaporating the water with the low-grade heat, the diphosphoric acid absorbing the evaporated water forming the phosphoric acid stream by de-oligomerization and hydrolysis of the diphosphoric acid and increasing a heat value of the low-grade heat; and decreasing the pressure on the phosphoric acid stream to repeat the cycle (i.e., decreasing a pressure of the phosphoric acid stream) ([0059]).
Claim 2 is rejected under 35 U.S.C. 103 as being unpatentable over Cruz in view of HEIL, as applied to claim 1 above, and further in view of MacArthur et al. (US 2011/0158900 A1).
Cruz in view of HEIL does not explicitly disclose that the low-pressure steam stream, or streams (more than one) comprises a first low-pressure steam stream having a first temperature and a first pressure, and a second low-pressure steam stream having a second temperature and a second pressure, the first temperature being different from the second temperature, or the first pressure being different from the second pressure, or both.
MacArthur discloses a process for hydrogen production and carbon dioxide capture through adsorption (Abstract; [0009]) wherein synthetic gas is shifted in a water gas shift reactor to create the carbon dioxide (Fig. 1; [0008]-[0009]). MacArthur teaches that the water gas shift reaction is usually carried out in two stages: a high temperature stage and a low temperature stage ([0032]) for bulk carbon monoxide conversion and final carbon monoxide conversion, respectively, the higher temperature stage allowing for the generation of high pressure steam ([0033]).
Therefore, before the effective filing date of the claimed invention it would have been obvious to one of ordinary skill in the art to modify the method of Cruz in view of HEIL by providing a first low-pressure steam stream having a first temperature and a first pressure, and a second low-pressure steam stream having a second temperature and a second pressure, the first temperature being different from the second temperature, or the first pressure being different from the second pressure, or both as taught by MacArthur because higher and lower temperature water gas shift reactions can generate higher and lower pressure steams in the interest of advantageously carrying out bulk and final conversions of carbon monoxide (MacArthur, [0032], [0033]).
Claim 4 is rejected under 35 U.S.C. 103 as being unpatentable over Cruz in view of HEIL, as applied to claim 3 above, and further in view of Deng et al. (US 2011/0146278 A1).
Cruz in view of HEIL does not explicitly disclose that the steam turbine is a condensing-induction steam turbine.
Deng teaches that conventional power generation with a heat recovery steam generator can use a condensing steam turbine with steam induction ([0025]: “HRSG”; [0038]).
Therefore, before the effective filing date of the claimed invention it would have been obvious to one of ordinary skill in the art to modify the method of Cruz in view of HEIL by providing a condensing-induction steam turbine as taught by Deng because a condensing steam turbine with steam induction was known to be used in a conventional power generation system using a heat recovery steam generator.
Claim 5 is rejected under 35 U.S.C. 103 as being unpatentable over Cruz in view of HEIL, as applied to claim 1 above, and further in view of Rafati et al. (US 2019/0135626 A1).
Cruz in view of HEIL does not explicitly disclose that the low-pressure steam stream is not superheated and further comprising superheating the low-pressure steam stream.
Rafati teaches methods for separation of carbon dioxide from a process stream, such as a process stream in a hydrogen production system (Abstract). Rafati teaches that the hydrogen production system can include a steam generating boiler that can be useful for cooling the product gas and producing high pressure saturated steam, which can be superheated using high temperature heat derived from a different source, with the superheated steam used as a feed to H2+CO reactor units ([0020]) such as a partial oxidation reactor ([0016]: “partial oxidation”).
Therefore, before the effective filing date of the claimed invention it would have been obvious to one of ordinary skill in the art to modify the method of Cruz in view of HEIL by providing a low-pressure steam stream that is not superheated and further comprising superheating the low-pressure steam stream as taught by Rafati because superheated steam used as a feed to H2+CO reactor unit (Rafati, [0020]).
Claim 7 is rejected under 35 U.S.C. 103 as being unpatentable over Cruz in view of HEIL, as applied to claim 1 above, and further in view of Bansal et al. (US 2025/0010259 A1).
Cruz in view of HEIL does not explicitly disclose separating the overhead stream from the CO2 recovery system into at least a second high-pressure hydrogen stream enriched in hydrogen, and a low-pressure CO2 stream enriched in carbon dioxide.
Regarding claim 7, Bansal discloses process for producing a hydrogen rich gas (Abstract) wherein a shifted gas stream 5 is fed to a hydrogen purification unit 125, e.g. a PSA-unit, from which a high-purity H2 stream as hydrogen product 8 is produced, as well as a CO2-rich off-gas stream 9, and this CO2-rich off-gas recycle stream 9 is conducted to CO2-removal section 180, from which CO2-product stream 11 is generated, as well as a CO2-depleted off-gas stream 17, 17′, 17″ (Fig. 1; [0120]). Bansal teaches that further enrichment of the CO2-depleted off-gas into a separate H2-product is not required when the CO2-depleted off-gas may have already the required specifications to be recycled to at least a feed side of a reforming unit ([0085]).
Therefore, before the effective filing date of the claimed invention it would have been obvious to one of ordinary skill in the art to modify the method of Cruz in view of HEIL by separating the overhead stream from the CO2 recovery system into at least a second high-pressure hydrogen stream enriched in hydrogen, and a low-pressure CO2 stream enriched in carbon dioxide as taught by Bansal because further enrichment of a CO2-depleted off-gas into a separate H2-product is not required when the CO2-depleted off-gas may have already the required specifications to be recycled to at least a feed side of a reforming unit (Bansal, [0085]), implicitly teaching that such a separation may be desirable where a specification is not met. A reference may be relied upon for all that it would have reasonably suggested to one having ordinary skill the art, and examples and preferred embodiments do not constitute a teaching away from a broader disclosure or non-preferred embodiments. See MPEP 2123 (I) and (II).
Claims 9 and 10 are rejected under 35 U.S.C. 103 as being unpatentable over Cruz in view of HEIL, as applied to claim 1 above, and further in view of Collins et al. (US 2017/0211891 A1).
Cruz in view of HEIL does not explicitly disclose a turbine that is connected to a generator through a speed reducing gear box (claim 9); or a turbine that is directly connected to the tail gas compressor or the refrigerant gas compressor with a speed-changing gear box and a motor (claim 10).
Collins teaches a compressor for a waste heat recovery system (Abstract) operating on passage of a fluid produced as a result of a waste heat recovery process ([0011]). Collins teaches compressor 52 capable of being driven by a prime mover 54 such as for example an electric motor as well as an expander 56 or turbine (Fig. 1; [0011], [0035]), the expander including a speed reducing transmission (i.e., a speed reducing gear box) and drive gear 82 to provide work to a shaft coupled with the compressor 52 (Figs. 2, 3; [0021]). Collins teaches that the motor is structured to provide work to a rotary compressor element that is structured to compress a fluid and thereby increase the pressure of the fluid ([0027]).
Therefore, before the effective filing date of the claimed invention it would have been obvious to one of ordinary skill in the art to modify the method of Cruz in view of HEIL by providing a turbine that is connected to a generator through a speed reducing gear box (claim 9); or a turbine that is directly connected to the tail gas compressor with a speed-changing gear box and a motor (claim 10) as taught by Collins because this configuration can increase the pressure of a fluid from a waste heat recovery system (Collins, [0027])
Claims 13, 15-16, and 18-19 are rejected under 35 U.S.C. 103 as being unpatentable over Cruz in view of Asfha (US 12,327,854 B2) and HEIL.
Regarding claim 13, Cruz discloses a process for producing a hydrogen-enriched product and recovering CO2 (Abstract) (i.e., a method of producing a hydrogen-enriched product and recovering CO2) comprising:
providing an effluent stream 445 from a WGS unit 430 comprising hydrogen and CO2 (Fig. 4; [0089]) regarded as a synthesis gas mixture (claim 1), obtained from an ATR/GHR process unit 420 and a WGS unit 430 ([0081]) used for producing the hydrogen (claims 1, 13; [0003]) (i.e., providing a synthesis gas stream comprising hydrogen and carbon dioxide from a hydrogen production process) and from which heat may be recovered ([0082]; claim 13) (i.e., the hydrogen production process producing low-grade heat);
generating steam from the effluent stream (claim 13) (i.e., producing a low-pressure steam stream from the low-grade heat);
separating the effluent stream 445 in a PSA system comprising two PSA units 510, 515 into a low-pressure tail gas stream 465 enriched in CO2 and high-pressure stream 520 comprising substantially all the hydrogen ([0090]), wherein the tail gas stream contains hydrogen ([0038]) (i.e., separating the synthesis gas stream in a hydrogen pressure swing adsorption (PSA) unit into a first high-pressure hydrogen stream enriched in hydrogen and a hydrogen depleted tail gas stream comprising a portion of the hydrogen and the carbon dioxide);
sending the low-pressure tail gas stream 465 enriched in CO2 to compressor 470 to form a low-pressure compressed tail gas stream 475 ([0085]) (i.e., compressing the hydrogen depleted tail gas stream in a tail gas compressor to form a compressed tail gas stream);
separating the low-pressure compressed tail gas stream 475 into a bottoms stream 490 comprising liquid CO2 and an overhead stream 495 in a CO2 recovery unit 480 ([0085]), the overhead stream comprising a portion of the hydrogen ([0042]) (i.e., separating the compressed tail gas stream in a CO2 recovery system into a CO2-enriched product stream and an overhead stream comprising the portion of the hydrogen); and
recovering the liquid CO2 stream ([0015]) (i.e., recovering the CO2-enriched product stream).
However, Cruz does not explicitly disclose (i) superheating the low-pressure steam stream; (ii) introducing the superheated low-pressure steam stream to a turbine to generate power; (iii) the tail gas compressor requiring a total amount of power to operate; the total amount of power to operate the tail gas compressor being reduced by 20% or more using the power produced by the turbine.
Regarding (i) and (ii), Asfha discloses a waste recovery system unit configured to capture and utilize waste heat (claim 1) including a compressor, a turbine, and an electric generator for facilitating the compression, expansion, and conversion of mechanical energy into electrical power (claim 8). Asfha teaches that a superheater can generate high-pressure steam to propel a steam turbine, augmenting electrical power production (col. 24, lines 20-23).
Therefore, before the effective filing date of the claimed invention it would have been obvious to one of ordinary skill in the art to modify the method of Cruz by (i) superheating the low-pressure steam stream; and (ii) introducing the superheated low-pressure steam stream to a turbine to generate power as taught by Asfha because (1) Cruz teaches that energy can be recovered from the WGS unit by cooling its effluent to generate steam (Cruz, [0059]); and (2) a superheater can generate high-pressure steam to propel a steam turbine, augmenting electrical power production (Asfha, col. 24, lines 20-23).
Regarding (iii), HEIL discloses a process for generating hydrogen and carbon dioxide (Abstract) wherein a synthesis gas stream comprising hydrogen and carbon dioxide (col. 15, lines 1-2) is passed to a CO2 removal unit 15 (Fig. 1; [0049]) that may be a PSA unit ([0026]) and separated into a carbon dioxide rich stream 16 and a hydrogen rich stream 17 ([0049]). HEIL teaches that the synthesis gas stream exits a Pox reactor unit 5 and is cooled by a waste heat boiler (steam generator) 9 to produce steam that is used for driving compressors via a stream turbine of an electrical generator ([0047]).
Therefore, before the effective filing date of the claimed invention it would have been obvious to one of ordinary skill in the art to modify the method of Cruz in view of Asfha by (iii) providing a tail gas compressor requiring a total amount of power to operate; using the power produced by the turbine as taught by HEIL because (1) Cruz teaches that energy can be recovered from the WGS unit by cooling its effluent to generate steam (Cruz, [0059]); (2) steam from recovered heat can be used for driving compressors via a stream turbine of an electrical generator (HEIL, [0047]); and (3) it would have been obvious to the skilled practitioner of Cruz in view of Asfha and HEIL that the compressor 470 can be powered by steam from recovered heat.
Regarding “the total amount of power to operate the tail gas compressor being reduced by 20% or more,” recognition by Applicant of an advantage which would flow naturally from following the suggestion of the prior art cannot be the basis for patentability when the differences would otherwise be obvious.” See MPEP 2145(II). Alternatively, it is asserted that, absent evidence to the contrary, one would reasonably expect that the method as taught by Cruz in view of Asfha and HEIL functions the same as the method recited in claim 11, since Cruz in view of Asfha and HEIL discloses the same method for producing a hydrogen-enriched product and recovering CO2 as claimed, considering that HEIL teaches the recovery of heat ([0029]) (i.e., power), so it would have been obvious to the practitioner of Cruz in view of Asfha and HEIL to maximize power recovery or efficiency through the heat recovery. If it is Applicant’s position that this would not be the case: (1) evidence would need to be provided to support Applicant’s position; and (2) it would be the Office’s position that the application contains inadequate disclosure as to how to obtain the claimed reduction in total amount of power with only the claimed steps.
Regarding claim 15, HEIL teaches that steam is used to drive a compressor via a turbine ([0047]) (i.e., wherein the turbine is a steam turbine).
Regarding claim 16, Cruz teaches that the feed gas can be process streams from new and existing hydrogen production processes such as steam reforming with an optional gas heated reformer, autothermal reforming with an optional gas heated reformer, gasification, or partial oxidation (POX) ([0024]) (i.e., wherein the hydrogen production process comprises a steam reforming unit with an optional gas heated reformer, an autothermal reforming unit with an optional gas heated reformer, a partial oxidation unit, or a gasification unit).
Regarding claim 18, HEIL teaches that the stream turbine may be used for an electrical generator ([0047]), so it would have been obvious to connect the turbine of Cruz in view of Asfha and HEIL to a generator to produce electricity (i.e., wherein the turbine is connected to a generator).
Regarding claim 19, Cruz teaches the production of higher value heat (i.e., increasing a temperature of the low-pressure steam stream) by contacting waste heat with phosphoric acid leading to oligomerization to diphosphoric acid and split off water molecules that condense (i.e., contacting the low-grade heat with a phosphoric acid stream comprising phosphoric acid to oligomerize the phosphoric acid forming a diphosphoric acid stream comprising diphosphoric acid and water; condensing the water); increasing the pressure of the diphosphoric acid stream (i.e., increasing a pressure of the diphosphoric acid stream); evaporating the water with the waste heat which is absorbed by the diphosphoric acid, causing de-oligomerization and hydrolysis to occur resulting in conversion back to phosphoric acid and the production of higher value process heat (i.e., evaporating the water with the low-grade heat, the diphosphoric acid absorbing the evaporated water forming the phosphoric acid stream by de-oligomerization and hydrolysis of the diphosphoric acid and increasing a heat value of the low-grade heat; and decreasing the pressure on the phosphoric acid stream to repeat the cycle (i.e., decreasing a pressure of the phosphoric acid stream) ([0059]).
Claim 14 is rejected under 35 U.S.C. 103 as being unpatentable over Cruz in view of HEIL, as applied to claim 13 above, and further in view of MacArthur.
Cruz in view of Asfha and HEIL does not explicitly disclose that the low-pressure steam stream(s) comprises a first low-pressure steam stream having a first temperature and a first pressure, and a second low-pressure steam stream having a second temperature and a second pressure, the first temperature being different from the second temperature, or the first pressure being different from the second pressure, or both.
MacArthur discloses a process for hydrogen production and carbon dioxide capture through adsorption (Abstract; [0009]) wherein synthetic gas is shifted in a water gas shift reactor to create the carbon dioxide (Fig. 1; [0008]-[0009]). MacArthur teaches that the water gas shift reaction is usually carried out in two stages: a high temperature stage and a low temperature stage ([0032]) for bulk carbon monoxide conversion and final carbon monoxide conversion, respectively, the higher temperature stage allowing for the generation of high pressure steam ([0033]).
Therefore, before the effective filing date of the claimed invention it would have been obvious to one of ordinary skill in the art to modify the method of Cruz in view of Asfha and HEIL by providing low-pressure steam stream(s) comprising a first low-pressure steam stream having a first temperature and a first pressure, and a second low-pressure steam stream having a second temperature and a second pressure, the first temperature being different from the second temperature, or the first pressure being different from the second pressure, or both as taught by MacArthur because higher and lower temperature water gas shift reactions can generate higher and lower pressure steams in the interest of advantageously carrying out bulk and final conversions of carbon monoxide (MacArthur, [0032], [0033]).
Claim Objections
Claim 17 is objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims.
Allowable Subject Matter
The following is a statement of reasons for the indication of allowable subject matter:
A thorough search for pertinent prior art did not locate any prior art that discloses or suggests the invention recited in claim 17.
The concept of a method of producing a hydrogen-enriched product and recovering CO2 comprising:
providing a synthesis gas stream comprising hydrogen and carbon dioxide from a hydrogen production process, the hydrogen production process producing low-grade heat;
producing a low-pressure steam stream from the low-grade heat;
separating the synthesis gas stream in a hydrogen pressure swing adsorption (PSA) unit into a first high-pressure hydrogen stream enriched in hydrogen and a hydrogen depleted tail gas stream comprising a portion of the hydrogen and the carbon dioxide;
compressing the hydrogen depleted tail gas stream in a tail gas compressor to form a compressed tail gas stream, the tail gas compressor requiring a total amount of power to operate, or compressing a refrigerant gas stream in a refrigerant gas compressor in a cryogenic fractionation CO2 process, the refrigerant gas compressor requiring a total amount of power to operate, or both;
superheating the low-pressure steam stream;
introducing the superheated low-pressure steam stream to a turbine to generate power, the total amount of power to operate the tail gas compressor, or the refrigerant gas compressor, or both being reduced by 20% or more using the power produced by the turbine;
separating the compressed tail gas stream in a CO2 recovery system into a CO2-enriched product stream and an overhead stream comprising the portion of the hydrogen; and
recovering the CO2-enriched product stream (claim 13);
further comprising separating the overhead stream from the CO2 recovery system into at least a second high-pressure hydrogen stream enriched in hydrogen, and a low-pressure CO2 stream enriched in carbon dioxide; and recycling the low-pressure CO2 stream to the tail gas compressor (claim 17)
is considered to define patentable subject matter over the prior art.
The closest prior art is Cruz et al. (US 2022/0306464 A1), which discloses providing an effluent stream 445 from a WGS unit 430 comprising hydrogen and CO2 (Fig. 4; [0089]) regarded as a synthesis gas mixture (claim 1), obtained from an ATR/GHR process unit 420 and a WGS unit 430 ([0081]) used for producing the hydrogen (claims 1, 13; [0003]);
generating steam from the effluent stream (claim 13);
separating the effluent stream 445 in a PSA system comprising two PSA units 510, 515 into a low-pressure tail gas stream 465 enriched in CO2 and high-pressure stream 520 comprising substantially all the hydrogen ([0090]), wherein the tail gas stream contains hydrogen ([0038]);
sending the low-pressure tail gas stream 465 enriched in CO2 to compressor 470 to form a low-pressure compressed tail gas stream 475 ([0085]) (i.e., compressing the hydrogen depleted tail gas stream in a tail gas compressor to form a compressed tail gas stream);
separating the low-pressure compressed tail gas stream 475 into a bottoms stream 490 comprising liquid CO2 and an overhead stream 495 in a CO2 recovery unit 480 ([0085]), the overhead stream comprising a portion of the hydrogen ([0042]); and
recovering the liquid CO2 stream ([0015])
Regarding claim 17, Cruz teaches recycling the overhead of a CO2 recovery system to the PSA system, a WGS reactor or the CO2 recovery system (claim 9), so the claimed further separation of claim 17 is not suggested. However, separating the overhead stream from the CO2 recovery system into at least a second high-pressure hydrogen stream enriched in hydrogen, and a low-pressure CO2 stream enriched in carbon dioxide would have been obvious in view of Bansal et al. (US 2025/0010259 A1), which teaches that further enrichment of a CO2-depleted off-gas into a separate H2-product is not required when the CO2-depleted off-gas may have already the required specifications to be recycled to at least a feed side of a reforming unit ([0085]), implicitly teaching the separation. However, Bansal does not suggest that, if such a separation were implemented, a resulting low-pressure CO2 stream should be recycled to a tail gas compressor.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to GABRIEL E GITMAN whose telephone number is (571)272-7934. The examiner can normally be reached M-Th 7:15-5:45pm.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, In Suk Bullock can be reached at 571-272-3471. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/GABRIEL E GITMAN/Primary Examiner, Art Unit 1772
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