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 .
Response to Amendment
The amendment filed August 12th, 2025 has been entered. Claims 1-22 remain pending
in the application. The amendments to the claims and specification have overcome each and every drawing objection, specification objection, claim objection, 112(b) rejection, and 112(d) previously cited on the Non-Final rejection mailed July 08th, 2025. However, the amendment has raised other issues detailed below.
Claim Rejections - 35 USC § 112(a)
Claim 11 is 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 11, lines 1-4 recite, “wherein an inlet pressure of the cold turbine/expander and an inlet pressure of the warm turbine/expander are equal and an outlet pressure of the cold turbine/expander and an outlet pressure of the warm turbine/ expander are equal”, however, there is no support in the present disclosure to support the inlet and outlet pressures of the cold turbine/expander and the warm turbine/expander are equal. The only part of the specification that gives any indication of inlet and outlet pressures of the cold turbine/expander and the warm turbine/expander is as follows and only specifies a pressure range for the exhaust stream 54 after being expanded in the warm turbine/expander 50, “The first diverted stream 52 is preferably in the range of 20% to 60% and more preferably about 40% by volume of the high pressure nitrogen refrigerant stream 39 and is expanded in the warm turbine/expander 50 down to a pressure in the range of 1.3 bar(a) to 10.0 bar(a) (Pg. 8, paragraph 19)”. The specification does not provide any specific inlet or outlet pressures for the cold turbine/expander and the warm turbine/expander or describe the pressures of the cold turbine/expander and the warm turbine/expander as being equal. See 112(b) rejections below.
Claim Rejections - 35 USC § 112(b)
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.
Claim 11 is 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 11, lines 1-4 recite, “wherein an inlet pressure of the cold turbine/expander and an inlet pressure of the warm turbine/expander are equal and an outlet pressure of the cold turbine/expander and an outlet pressure of the warm turbine/ expander are equal” which is unclear to the Examiner as the present disclosure does not provide any support for the inlet and outlet pressures of the cold turbine/expander and the warm turbine/expander being equal. For purposes of examination, the Examiner will interpret the claim to simply require similar pressure differentials between the inlet and outlets of the cold turbine/expander and the warm turbine/expander.
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 1 is rejected under 35 U.S.C. 103 as being unpatentable over Zhao et al. (US 20240418437), hereinafter Zhao in view of Allam et al. (US Patent No. 6,484,533), hereinafter Allam.
Regarding claim 1, Zhao discloses a refrigeration system for precooling of hydrogen and liquefaction of nitrogen (Fig. 2, an intermediate-pressure thermosiphon nitrogen liquid stream 530; Pg. 13, paragraph 91, FIG. 2 illustrates an embodiment of a hydrogen liquefaction system similar to FIG. 1. However, in the embodiment in FIG. 2, the first nitrogen circulation compressor 1800 may be combined with the integrated nitrogen compander 1600 on the same integral-gear 1020), the refrigeration system comprising:
an integral gear machine comprising a drive assembly, a bull gear, and a plurality of pinions arranged to drive refrigerant compression stages of the refrigeration system and for receiving work produced by at least two turbine/expanders of the refrigeration system (See annotated Fig. 2 of Zhao below, integrated nitrogen compander 1600, common integral-gear 1020, plurality of pinions A, first nitrogen circulation compressor 1800, second nitrogen circulation compressor 1700, warm nitrogen turbo-expander 1004, cold nitrogen turbo-expander 1006; Pg. 10, paragraph 66, In embodiments, the integrated nitrogen compander 1600 may be driven either by an electrical motor, a gas turbine, or a steam turbine);
a refrigeration circuit configured to circulate a plurality of nitrogen streams including a high pressure nitrogen refrigerant stream and a hydrogen feed stream (Fig. 2, intermediate-pressure circulation gaseous nitrogen stream 500, mixed intermediate-pressure circulation gaseous nitrogen stream 502, high-pressure circulation nitrogen stream 506, side-stream warm nitrogen turbo expander feed stream 508, warm nitrogen turbo-expander discharge stream 510, second nitrogen mixed stream 512, side-stream cold nitrogen turbo-expander feed stream 516, cold nitrogen turbo-expander discharge stream 518, first nitrogen mixed stream 520, subcooled high-pressure circulation liquid nitrogen stream 522, second subcooled high-pressure circulation liquid nitrogen stream 524, intermediate-pressure cold circulation nitrogen stream 526, intermediate-pressure thermosiphon nitrogen vapor stream 528, intermediate-pressure thermosiphon nitrogen liquid stream 530, an intermediate-pressure thermosiphon nitrogen mixed stream 532, first subcooled high-pressure circulation liquid nitrogen stream 534, low-pressure cold circulation nitrogen stream 536, low-pressure thermosiphon nitrogen vapor stream 538, low-pressure thermosiphon nitrogen liquid stream 540, low-pressure thermosiphon nitrogen mixed stream 542, low-pressure circulation gaseous nitrogen stream 544, first nitrogen circulation compressor discharge stream 548; purified gaseous hydrogen feed stream 100);
an expansion valve disposed in the refrigeration circuit configured for expanding the high pressure nitrogen refrigerant stream to yield a two-phase nitrogen stream (Fig. 2, first circulation liquid nitrogen pressure let-down valve 1012, second circulation liquid nitrogen pressure let-down valve 1008; low-pressure cold circulation nitrogen stream 536; intermediate-pressure cold circulation nitrogen stream 526; Pg. 8, paragraph 57, In embodiments, the first subcooled high-pressure circulation liquid nitrogen stream 534 may exit the first circulation liquid nitrogen pressure let-down valve 1012 as the low-pressure cold circulation nitrogen stream 536. In embodiments, due to the isenthalpic pressure drop through the first circulation liquid nitrogen pressure let-down valve 1012, there may be about 35% nitrogen vapor flash-out from the low-pressure cold circulation nitrogen stream 536; Pg. 9, paragraph 61, In embodiments, the second circulation liquid nitrogen pressure let-down valve 1008 may comprise a J/T valve. In embodiments, the second subcooled high-pressure circulation liquid nitrogen stream 524 may exit the second circulation liquid nitrogen pressure let-down valve 1008 as the intermediate-pressure cold circulation nitrogen stream 526. In embodiments, due to the isenthalpic pressure drop occurring as the second subcooled high-pressure circulation liquid nitrogen stream 526 passes through the second circulation liquid nitrogen pressure let-down valve 1008, there may be about 18% nitrogen vapor flash-out from the intermediate-pressure cold circulation nitrogen stream 526);
a phase separator disposed within the refrigeration circuit and in fluid communication with the expansion valve and configured to receive the two-phase nitrogen stream and separate the two-phase nitrogen stream into a nitrogen liquid and a gaseous nitrogen stream (Fig. 2, intermediate pressure nitrogen thermosiphon vessel 1010, low-pressure nitrogen thermosiphon vessel 1014; Pg. 8, paragraph 57, In embodiments, the two-phase low-pressure cold circulation nitrogen stream 536 may be introduced to the low-pressure nitrogen thermosiphon vessel 1014, wherein the liquid and vapor in the low-pressure cold circulation nitrogen stream 536 may be separated into the low-pressure thermosiphon nitrogen liquid stream 540 and the low-pressure thermosiphon nitrogen vapor stream 536; Pg. 9, paragraph 61, In embodiments, the two-phase intermediate-pressure cold circulation nitrogen stream 526 may enter the intermediate pressure nitrogen thermosiphon vessel 1010, wherein the liquid and vapor in the intermediate-pressure cold circulation nitrogen stream 526 may be separated into the intermediate-pressure thermosiphon nitrogen liquid stream 530 and the intermediate-pressure thermosiphon nitrogen vapor stream 528);
a first heat exchanger or set of first heat exchange cores disposed within the refrigeration circuit and configured to cool the hydrogen feed stream and cool the high pressure nitrogen refrigerant stream via indirect heat exchange with exhaust streams from the at least two turbine/expanders and the gaseous nitrogen stream from the phase separator (Fig. 2, precooling main heat exchanger 606, pass 1-1, pass 1-2, pass 1-3, pass 1-5, pass 1-7; Pg. 6, paragraph 45, In embodiments, the first split gaseous hydrogen stream 114 may proceed to a pass 1-3 from the warm end of a precooling main heat exchanger 606, wherein the first split gaseous hydrogen stream 114 may exchange heat with cold passes 1-2, 1-4, 1-5 and 1-7; Pg. 8, paragraph 55, In embodiments, the high-pressure circulation nitrogen stream 506 may enter pass 1-1 from the warm end of the precooling main heat exchanger 606, wherein the high-pressure circulation nitrogen stream 506 may exchange heat with the cold stream passes 1-2, 1-4, 1-5 and 1-7. In embodiments, the side-stream warm nitrogen turbo-expander feed stream 508 may exit pass 1-1, wherein the side-stream warm nitrogen turbo-expander feed stream 508 may comprise a temperature of about 286K. Further, in embodiments the side-stream cold nitrogen turbo-expander feed stream 516 may also exit from pass 1-1, wherein the side-stream cold nitrogen turbo-expander feed stream 516 may comprise a temperature of about 174K); and
a second heat exchanger or set of second heat exchange cores disposed within the refrigeration circuit and configured to receive the cooled hydrogen feed stream from the first heat exchanger or the set of first heat exchange cores and precool the cooled hydrogen feed stream to a temperature of about 80 Kelvin or lower via indirect heat exchange with all or a portion of the liquid nitrogen stream received from the phase separator (Fig. 2, precooling main heat exchanger 606, pass 1-3, pass 1-4, pass 1-8; Pg. 7, paragraph 47, In embodiments, the first p-H2 enriched gaseous hydrogen stream 128 may be routed back to pass 1-8 of the precooling main heat exchanger 606, wherein the first p-H2 enriched gaseous hydrogen stream 128 may be cooled down to a temperature of 82K. In embodiments, a first cold p-H2 enriched gaseous hydrogen stream 130 may exit pass 1-8 of the precooling main heat exchanger 606; Pg. 8-9, paragraph 57, In embodiments, the low-pressure thermosiphon nitrogen liquid stream 540 may flow to the pass 1-4 inlet at the cold end of the precooling main heat exchanger 606, wherein the low-pressure thermosiphon nitrogen liquid stream 540 may vaporize while traveling upward in pass 1-4 to provide cooling to the warm stream passes 1-3, 1-6 and 1-8 at the cold-end section of the precooling main heat exchanger 606; Further, a prima facie case of obviousness exists where the claimed ranges or amounts do not overlap with the prior art but are merely close. In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955) (Claimed process which was performed at a temperature between 40°C and 80°C and an acid concentration between 25% and 70% was held to be prima facie obvious over a reference process which differed from the claims only in that the reference process was performed at a temperature of 100°C and an acid concentration of 10%). MPEP § 2144.05-I).
However, Zhao does not disclose the integral gear machine comprising the plurality of pinions arranged to drive four or more refrigerant compression stages.
Allam teaches the integral gear machine comprising the plurality of pinions arranged to drive four or more refrigerant compression stages (Fig. 4, first compressor pinion shaft 10, second compressor pinion shaft 11, expansion turbine pinion shaft 15, first-stage C1, second-stage C2, third-stage C3, fourth-stage C4, expansion turbine 14, second expansion turbine 16, bullgear 12, drive shaft 13; Col. 12, lines 35-37, FIG. 4 is a diagrammatic representation of a third arrangement of the gear drive between a four-stage centrifugal compressor and two expansion turbines).
Therefore, it would have been obvious before the effective filing date of the claimed invention to replace the nitrogen commander 1600 of the refrigeration system of Zhao of claim 1 with the integrally geared turbomachine having four refrigerant compression stages of Allam. One of ordinary skill in the art would have been motivated to make this modification to provide a reduction of the capital cost and ease of construction of liquefiers without sacrificing efficiency (Allam, Col. 2, lines 9-10).
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Annotated Fig. 2 of Zhao
Claims 2-15 are rejected under 35 U.S.C. 103 as being unpatentable over Zhao as modified by Allam as applied to claim 1 above, and further in view of Posser et al. (US 20220404094), hereinafter Posser.
Regarding claim 2, Zhao as modified discloses the refrigeration system of claim 1 (see the combination of references used in the rejection of claim 1 above), wherein:
the refrigeration circuit further comprises a low pressure nitrogen recycle stream, a nitrogen refrigerant stream and direct the nitrogen refrigerant stream to a nitrogen feed compressor (Fig. 2, low-pressure thermosiphon nitrogen mixed stream 542, low-pressure circulation gaseous nitrogen stream 544, first nitrogen circulation compressor 1800);
wherein the refrigeration circuit is further configured to mix the compressed nitrogen refrigerant stream from the nitrogen feed compressor with a nitrogen recycle stream and direct the mixed stream to a nitrogen recycle compressor (Fig. 2, mixed intermediate-pressure circulation gaseous nitrogen stream 502, second nitrogen circulation compressor 1700; Pg. 9, paragraph 59, In embodiments, the first nitrogen circulation compressor discharge stream 548 may comingle with the intermediate-pressure circulation gaseous nitrogen stream 500 to form the mixed intermediate-pressure circulation gaseous nitrogen stream 502, wherein the mixed intermediate-pressure circulation gaseous nitrogen stream 502 may become the first stage feed stream to a second nitrogen circulation compressor 1700).
However, Zhao as modified does not disclose the refrigeration circuit is further configured to mix a nitrogen feed stream and the low pressure nitrogen recycle stream to form the nitrogen refrigerant stream and direct the nitrogen refrigerant stream to the nitrogen feed compressor; and
wherein the refrigeration circuit is further configured to direct the further compressed nitrogen refrigerant stream to a warm booster compressor and a cold booster compressor to still further compress the nitrogen refrigerant stream and form the high pressure nitrogen refrigerant stream.
Prosser teaches the refrigeration circuit is further configured to mix a nitrogen feed stream and the low pressure nitrogen recycle stream to form the nitrogen refrigerant stream and direct the nitrogen refrigerant stream to the nitrogen feed compressor (Fig. 2, small make-up flow 111, low pressure return circuit 123, low-pressure recycle compressor 113; Pg. 5, paragraph 39, The low pressure recycle compressor 113 raises the pressure of the combined feed stream made up of the warmed low pressure flash gas stream 144 and return stream 145 from the refrigeration load 120. A small make-up flow 111 may be required to compensate for leakage losses in the turbomachinery); and
wherein the refrigeration circuit is further configured to direct the further compressed nitrogen refrigerant stream to a warm booster compressor and a cold booster compressor to still further compress the nitrogen refrigerant stream and form the high pressure nitrogen refrigerant stream (Fig. 2, discharge stream 115, warm booster 172, cold booster 176, combined stream 17; Pg. 5, paragraph 39, The discharge stream 115 from the medium pressure recycle compressor 114 is fed to the warm booster 172 and cold booster 176 in parallel, and their respective discharge streams 173 and 177 are recombined to form combined stream 178 at the highest pressure in the cycle before they enter the heat exchanger 112).
Therefore, it would have been obvious before the effective filing date of the claimed invention to modify the refrigeration system of Zhao as modified to include a feed stream, a warm booster compressor, and a cold booster compressor as taught by Prosser. One of ordinary skill in the art would have been motivated to make this modification because higher pressure within the liquefaction cycle improves the thermodynamic efficiency of the nitrogen refrigerator by improving the reversibility of the heat exchanger temperature profile and because of the higher heat capacity of the feed streams (Prosser, Pg. 5, paragraph 42).
Regarding claim 3, Zhao as modified discloses the refrigeration system of claim 2 (see the combination of references used in the rejection of claim 2 above), wherein the warm booster compressor and the cold booster compressor are arranged in parallel (Prosser, Pg. 5, paragraph 39, The
discharge stream 115 from the medium pressure recycle compressor 114 is fed to the warm booster 172 and cold booster 176 in parallel, and their respective discharge streams 173 and 177 are recombined to form combined stream 178 at the highest pressure in the cycle before they enter the heat exchanger 112). Further, the limitations of claim 3 are the result of the modification of references used in the rejection of claim 2 above
Regarding claim 4, Zhao as modified discloses the refrigeration system of claim 2 (see the combination of references used in the rejection of claim 2 above).
However, Zhao as modified does not disclose wherein the warm booster compressor and the cold booster compressor are arranged in series.
Prosser teaches wherein the warm booster compressor and the cold booster compressor are arranged in series (Fig. 4, Pg. 5, paragraph 41, the warm booster 172 and cold booster 176 operate in series rather than parallel, with a portion of the recycle compressor discharge shown as stream 138 first compressed in the warm booster 172, then in the cold booster 176).
Therefore, it would have been obvious before the effective filing date of the claimed invention to modify the warm booster compressor and the cold booster compressor of the refrigeration system of Zhao as modified to be arranged in series as taught by Prosser. One of ordinary skill in the art would have been motivated to make this modification to make use of an additional heat exchange zone within the main heat exchanger to improve overall system efficiencies (Prosser, Pg. 5, paragraph 41).
Regarding claim 5, Zhao as modified discloses the refrigeration system of claim 2 (see the combination of references used in the rejection of claim 2 above), further comprising a high pressure hydrogen stream at a pressure of greater than or equal to about 40 bar(a) and is circulated through the refrigeration circuit and cooled in the first heat exchanger or the set of first heat exchange cores to a temperature of about 80 Kelvin (Zhao, Fig. 2, first split gaseous hydrogen stream 114; Pg. 6, paragraphs 45, In embodiments, the second hydrogen circulation compressor final stage discharge stream 112 may comprise a pressure within the range of 3,200 kPa·G to 4,000 kPa·G and a temperature of about 313K. In embodiments, the second hydrogen circulation compressor final stage discharge stream 112 may split into two streams. In embodiments, the second hydrogen circulation compressor final stage discharge stream 112 may split into a first split gaseous hydrogen stream 114 and a second split gaseous hydrogen stream 200. In embodiments, the first split gaseous hydrogen stream 114 may proceed to a pass 1-3 from the warm end of a precooling main heat exchanger 606, wherein the first split gaseous hydrogen stream 114 may exchange heat with cold passes 1-2, 1-4, 1-5 and 1-7. In embodiments, the first split gaseous hydrogen stream 114 may exit the precooling main heat exchanger 606 as a first cold gaseous hydrogen stream 116. In embodiments, the first cold gaseous hydrogen stream 116 may comprise a temperature of about 82K). Further, a prima facie case of obviousness exists where the claimed ranges or amounts do not overlap with the prior art but are merely close. In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955) (Claimed process which was performed at a temperature between 40°C and 80°C and an acid concentration between 25% and 70% was held to be prima facie obvious over a reference process which differed from the claims only in that the reference process was performed at a temperature of 100°C and an acid concentration of 10%). (MPEP § 2144.05-I).
Regarding claim 6, Zhao as modified discloses the refrigeration system of claim 2 (see the combination of references used in the rejection of claim 2 above), further comprising one or more hydrogen return streams that are circulated through the refrigeration circuit and the first heat exchanger or the set of first heat exchange cores to cool the high pressure nitrogen refrigerant stream and the hydrogen feed stream (Zhao, Fig. 2, intermediate temperature low-pressure circulation gaseous hydrogen stream 148; intermediate temperature intermediate-pressure circulation gaseous hydrogen stream 218; Pg. 11-12, paragraphs 74, In embodiments, the intermediate temperature low pressure circulation gaseous hydrogen stream 148 may comprise a pressure of about 36.5 kPa·G and a temperature of about 80.3K. In embodiments, the intermediate temperature low-pressure circulation gaseous hydrogen stream 148 may be routed to enter pass 1-5 from the cold end of the precooling main heat exchanger 606, wherein the intermediate temperature low-pressure circulation gaseous hydrogen stream 148 may exchange heat with the warm stream passes 1-1, 1-3, 1-6 and 1-8. In embodiments, the temperature of the intermediate temperature low-pressure circulation gaseous hydrogen stream 148 may be increased to about 311K. In embodiments, the intermediate temperature low; Pg. 12, paragraph 81, In embodiments, the intermediate temperature intermediate-pressure circulation gaseous hydrogen stream 218 may proceed to enter pass 1-7 from the cold end of the precooling main heat exchanger 606, wherein the intermediate temperature intermediate-pressure circulation gaseous hydrogen stream 218 may exchange heat with the warm stream passes 1-1, 1-3, 1-6 and 1-8. In embodiments, the temperature of the intermediate temperature intermediate-pressure circulation gaseous hydrogen stream 218 may be increased to about 311K. In embodiments, the intermediate temperature intermediate-pressure circulation gaseous hydrogen stream 218 may exit the precooling main heat exchanger 606 from its warm end as the intermediate-pressure circulation gaseous hydrogen stream 220).
Regarding claim 7, Zhao as modified discloses the refrigeration system of claim 2 (see the combination of references used in the rejection of claim 2 above).
However, Zhao as modified does not disclose wherein a portion of the liquid nitrogen stream from the phase separator is taken as a liquid nitrogen product stream.
Allam teaches wherein a portion of the liquid nitrogen stream from the phase separator is taken as a liquid nitrogen product stream (Fig. 5, liquid product stream 210; Col. 14, lines 14-18, The liquid fraction flows from the separator S1 as a liquid product stream 210. The liquid product stream 210 could be subcooled against a vaporizing portion of the liquid product as is well known in the art).
Therefore, it would have been obvious before the effective filing date of the claimed invention to modify the refrigeration system of Zhao as modified wherein a portion of the liquid nitrogen stream from the phase separator is taken as a liquid nitrogen product stream as taught by Allam. One of ordinary skill in the art would have been motivated to make this modification to improve overall system costs by selling a byproduct of the refrigeration system.
Regarding claim 8, Zhao as modified discloses the refrigeration system of claim 2 (see the combination of references used in the rejection of claim 2 above), wherein the at least two turbine/expanders further comprise a warm turbine/expander disposed in the refrigeration circuit and configured to receive a first diverted portion of the high pressure nitrogen refrigerant stream and a cold turbine/expander disposed in the refrigeration circuit and configured to receive a second diverted portion of the high pressure nitrogen refrigerant stream (Zhao, Fig. 2, warm nitrogen turbo-expander 1004, cold nitrogen turbo-expander 1006, side-stream warm nitrogen turboexpander feed stream 508, side-stream cold nitrogen turbo-expander feed stream 516).
Regarding claim 9, Zhao as modified discloses the refrigeration system of claim 2 (see the combination of references used in the rejection of claim 2 above), wherein the first diverted stream is expanded in the warm turbine/expander to yield a warm exhaust stream at a temperature of about 170 Kelvin; and wherein the warm exhaust stream is warmed to ambient temperatures in the first heat exchanger or the first set of heat exchanger cores (Zhao, Fig. 2, warm nitrogen turbo-expander discharge stream 510; Pg. 9, paragraph 61, In embodiments, the first nitrogen mixed stream 520 may continue traveling upward in pass 1-2 to provide cooling to warm passes 1-1, 1-3 and 1-6 at the mid-section of the precooling main heat exchanger 606 until the first nitrogen mixed stream 520 mixes with a warm nitrogen turbo expander discharge stream 510 at a temperature of about 180K to form the second nitrogen mixed stream 512. In embodiments, the second nitrogen mixed stream 512 may continue traveling upward in pass 1-2 to provide cooling to warm passes 1-1, 1-3 and 1-6 at the upper section of the precooling main heat exchanger 606 until the second nitrogen mixed stream 512 exits from the warm end of the precooling main heat exchanger 606 at a temperature of about 311K as the intermediate-pressure circulation gaseous nitrogen stream 500; Pg. 9-10, paragraph 62, In embodiments, the side-stream warm nitrogen turbo-expander feed stream 508 may enter the warm nitrogen turbo-expander 1004, wherein the side-stream warm nitrogen turbo-expander feed stream 508 may be expanded to a lower pressure of about 543 kPa ·G, which may result in a lower temperature of about 180K through a nearly isentropic expansion. In embodiments, the side-stream warm nitrogen turbo-expander feed stream 508 may exit the warm nitrogen turbo-expander 1004 as the warm nitrogen turbo expander discharge stream 510. In embodiments, the warm nitrogen turbo-expander discharge stream 510 may be routed into pass 1-2 of the precooling main heat exchanger 606, wherein the warm nitrogen turbo-expander discharge stream 510 may mix with the cold upcoming gaseous nitrogen 520 to provide cooling to the warm stream passes of the precooling main heat exchanger 606). Further, a prima facie case of obviousness exists where the claimed ranges or amounts do not overlap with the prior art but are merely close. In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955) (Claimed process which was performed at a temperature between 40°C and 80°C and an acid concentration between 25% and 70% was held to be prima facie obvious over a reference process which differed from the claims only in that the reference process was performed at a temperature of 100°C and an acid concentration of 10%). (MPEP § 2144.05-I).
However, Zhao as modified does not disclose wherein the first diverted stream is less than or equal to about 40% by volume of the high pressure nitrogen refrigerant stream.
Prosser teaches wherein the first diverted stream is less than or equal to about 40% by volume of the high pressure nitrogen refrigerant stream (Fig. 2; Pg. 4, paragraph 39 In a conventional nitrogen liquefier, the warm turbine flow is typically about one-half of the cold turbine flow for this cycle. In this case, though, with essentially all the liquid nitrogen produced at the cold end is returned to the nitrogen refrigerator as a cold gas, the refrigeration demand for the warm turbine is comparatively lower. So, the warm turbine flow in the embodiment of FIG. 2 is preferably only between about 10% to about 20% of the cold turbine flow). Further, In the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990) (The prior art taught carbon monoxide concentrations of “about 1-5%” while the claim was limited to “more than 5%.” The court held that “about 1-5%” allowed for concentrations slightly above 5% thus the ranges overlapped.) (MPEP § 2144.05-I).
Therefore, it would have been obvious before the effective filing date of the claimed invention to modify the first diverted stream of the refrigeration system of Zhao as modified to be less than or equal to about 40% by volume of the high pressure nitrogen refrigerant stream as taught by Prosser. One of ordinary skill in the art would have been motivated to make this modification to improve overall system efficiency by allowing sufficient flow to be diverted to the cold expansion turbine.
Regarding claim 10, Zhao as modified discloses the refrigeration system of claim 9 (see the combination of references used in the rejection of claim 9 above), wherein the second diverted stream is greater than the volume of the first diverted stream and is expanded in the cold turbine/expander to yield a cold exhaust stream at a temperature of about 97 Kelvin; and wherein the cold exhaust stream is warmed to ambient temperatures in the first heat exchanger or the first set of heat exchanger cores (Prosser, Fig. 2; Pg. 4, paragraph 39 In a conventional nitrogen liquefier, the warm turbine flow is typically about one-half of the cold turbine flow for this cycle. In this case, though, with essentially all the liquid nitrogen produced at the cold end is returned to the nitrogen refrigerator as a cold gas, the refrigeration demand for the warm turbine is comparatively lower. So, the warm turbine flow in the embodiment of FIG. 2 is preferably only between about 10% to about 20% of the cold turbine flow; Zhao, Pg. 9, paragraph 61, In embodiments, the first nitrogen mixed stream 520 may continue traveling upward in pass 1-2 to provide cooling to warm passes 1-1, 1-3 and 1-6 at the mid-section of the precooling main heat exchanger 606 until the first nitrogen mixed stream 520 mixes with a warm nitrogen turbo expander discharge stream 510 at a temperature of about 180K to form the second nitrogen mixed stream 512. In embodiments, the second nitrogen mixed stream 512 may continue traveling upward in pass 1-2 to provide cooling to warm passes 1-1, 1-3 and 1-6 at the upper section of the precooling main heat exchanger 606 until the second nitrogen mixed stream 512 exits from the warm end of the precooling main heat exchanger 606 at a temperature of about 311K as the intermediate-pressure circulation gaseous nitrogen stream 500; Pg. 10, paragraph 63, In embodiments, the side-stream cold nitrogen turbo expander feed stream 516 may enter the cold nitrogen turbo-expander 1006, where the side-stream cold nitrogen turbo-expander feed stream 516 may be expanded to a lower pressure of about 560 kPa·G resulting in a lower temperature of about 105K through a nearly isentropic expansion. In embodiments, the side-stream cold nitrogen turbo-expander feed stream 516 may exit the cold nitrogen turbo-expander 1006 as the cold nitrogen turbo-expander discharge stream 518. In embodiments, the cold nitrogen turbo-expander discharge stream 518 may enter pass 1-2 of the precooling main heat exchanger 606, where the cold nitrogen turbo expander discharge stream 518 may mix with the intermediate-pressure thermosiphon nitrogen mixed stream 532 to provide cooling to the warm stream passes of the precooling main heat exchanger 606). Further, In the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990) (The prior art taught carbon monoxide concentrations of “about 1-5%” while the claim was limited to “more than 5%.” The court held that “about 1-5%” allowed for concentrations slightly above 5% thus the ranges overlapped.) (MPEP § 2144.05-I). Additionally, a prima facie case of obviousness exists where the claimed ranges or amounts do not overlap with the prior art but are merely close. In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955) (Claimed process which was performed at a temperature between 40°C and 80°C and an acid concentration between 25% and 70% was held to be prima facie obvious over a reference process which differed from the claims only in that the reference process was performed at a temperature of 100°C and an acid concentration of 10%). (MPEP § 2144.05-I). Further, the limitations of claim 10 are the result of the modification of references used in the rejection of claim 9 above.
Regarding claim 11, Zhao as modified discloses the refrigeration system of claim 10 (see the combination of references used in the rejection of claim 10 above), wherein an inlet pressure of the cold turbine/expander and an inlet pressure of the warm turbine/expander are equal and an outlet pressure of the cold turbine/expander and an outlet pressure of the warm turbine/expander are approximately equal (Zhao, Pg. 9, paragraph 62, Returning to the side-stream warm nitrogen turbo expander feed stream 508, in embodiments the side-stream warm nitrogen turbo-expander feed stream 508 may comprise a pressure of about 4410 kPa·G and a temperature of about 286K. In embodiments, the side-stream warm nitrogen turbo-expander feed stream 508 may enter the warm nitrogen turbo-expander 1004, wherein the side-stream warm nitrogen turbo-expander feed stream 508 may be expanded to a lower pressure of about 543 kPa ·G; Pg. 9, paragraph 63; Returning to the side-stream cold nitrogen turbo expander feed stream 516, in embodiments the side-stream cold nitrogen turbo-expander feed stream 516 may comprise a pressure of about 4,395 kPa·G and a temperature of about 174K. In embodiments, the side-stream cold nitrogen turbo expander feed stream 516 may enter the cold nitrogen turbo-expander 1006, where the side-stream cold nitrogen turbo-expander feed stream 516 may be expanded to a lower pressure of about 560 kPa·G resulting in a lower temperature of about 105K through a nearly isentropic expansion; As best understood, see 112(b) rejections above).
Regarding claim 12, Zhao as modified discloses the refrigeration system of claim 8 (see the combination of references used in the rejection of claim 8 above), wherein the integral gear machine is a BriM machine and wherein the warm turbine/expander and the warm booster compressor or the cold booster compressor are operatively coupled to a first pinion of the plurality of pinions, and the cold turbine/expander and the other of the warm booster compressor or the cold booster compressor are operatively coupled to a second pinion of the plurality of pinions (Allam, Fig. 4, first compressor pinion shaft 10, second compressor pinion shaft 11, expansion turbine pinion shaft 15, first-stage C1, second-stage C2, third-stage C3, fourth-stage C4, expansion turbine 14, second expansion turbine 16, bullgear 12, drive shaft 13; Col. 12, lines 35-37, FIG. 4 is a diagrammatic representation of a third arrangement of the gear drive between a four-stage centrifugal compressor and two expansion turbines; Col. 13, lines 27-32, However, in FIG. 4, the "warm" expansion turbine 14 is mounted opposite the third-stage C3 of the compressor on the compressor pinion shaft 11. In addition, the fourth-stage C4 of the compressor is mounted opposite the “cold” expansion turbine 16 on the expansion turbine pinion shaft 15). Further, the limitations of claim 12 are the result of the modification of references used in the rejection of clam 8 above.
Regarding claim 13, Zhao as modified discloses the refrigeration system of claim 12 (see the combination of references used in the rejection of claim 12 above), wherein two or more compression stages of the nitrogen recycle compressor are operatively coupled to a third pinion of the plurality of pinions (Fig. 4 of Allam depicts first and second stages C1, C2 of the compressor to be mounted on the first compressor pinion shaft 10). Further, the limitations of claim 13 are the result of the modification of references used in the rejection of clam 12 above.
Regarding claim 14, Zhao as modified discloses the refrigeration system of claim 2 (see the combination of references used in the rejection of claim 2 above), further comprising an ortho/para conversion catalyst vessel configured to treat the precooled hydrogen feed stream exiting the second heat exchanger or the set of second heat exchanger cores (Zhao, Fig. 2, fixed bed catalyst converter 612; Pg. 7, paragraph 47, In embodiments, the deep purified cold gaseous hydrogen stream 126 may be brought to an equilibrium composition between the two spin isomers o-H2 and p-H2. In embodiments, this equilibrium may be obtained by passing the deep purified cold gaseous hydrogen stream 126 through the fixed-bed catalyst converter 612 that may catalyze the spontaneous and exothermic conversion of o-H2 to p-H2. In embodiments, it may be assumed that the fixed-bed catalyst converter 612 is sufficiently long to allow the new o-H2 and p-H2 equilibrium state to form).
Regarding claim 15, Zhao as modified discloses the refrigeration system of claim 14 (see the combination of references used in the rejection of claim 14 above), wherein the second heat exchanger or the set of second heat exchanger cores is further configured to re-cool the treated precooled hydrogen feed stream to a temperature of about 80 Kelvin (Zhao, Fig. 2; Pg. 7, paragraph 47, In embodiments, a first p-H2 enriched gaseous hydrogen stream 128 may exit the fixed bed catalyst converter 612, wherein the first p-H2 enriched gaseous hydrogen stream 128 may comprise a new equilibrium of about 53% o-H2 and about 47% p-H2 with a temperature of about 89K due to the exothermic conversion process. In embodiments, the first p-H2 enriched gaseous hydrogen stream 128 may be routed back to pass 1-8 of the precooling main heat exchanger 606, wherein the first p-H2 enriched gaseous hydrogen stream 128 may be cooled down to a temperature of 82K. In embodiments, a first cold p-H2 enriched gaseous hydrogen stream 130 may exit pass 1-8 of the precooling main heat exchanger 606).
Claim 16 is rejected under 35 U.S.C. 103 as being unpatentable over Zhao as modified by Allam and Prosser as applied to claim 8 above, and further in view of Knoche (US 20230392859), hereinafter Knoche.
Regarding claim 15, Zhao as modified discloses the refrigeration system of claim 8 (see the combination of references used in the rejection of claim 8 above).
However, Zhao as modified does not disclose wherein one or more heat exchange passages in the first heat exchanger or the second heat exchanger are configured to cool or re-cool the hydrogen feed stream containing ortho/para conversion catalysts.
Knoche teaches wherein one or more of the heat exchange passages in the first or second heat exchangers configured to cool or re-cool the hydrogen feed stream contain ortho/para conversion catalysts (Fig. 1, heat exchangers 14a-14b and 26a-26f; Pg. 3, paragraph 24, Heat exchanger 14b may contain an ortho-para conversion catalyst 18 that converts ortho-hydrogen to para-hydrogen to reduce volatilization. In the case of hydrogen liquefaction, maximal conversion of ortho to para hydrogen is achieved in this first reactor segment 18. The catalyst 18 may also be provided in heat exchanger 14a or provided solely in heat exchanger 14a instead; Pg. 3, paragraph 26, The ortho-para conversion catalyst is also provided in each of the heat exchangers 26a-26/for stream 22 so that ortho-para conversion is performed in parallel to the refrigeration, in order to minimize exergy losses).
Therefore, it would have been obvious before the effective filing date of the claimed invention to modify one or more of the heat exchange passages in the first or second heat exchangers of the refrigeration system of Zhao as modified to contain ortho/para conversion catalysts as taught by Knoche. One of ordinary skill in the art would have been motivated to make this modification so that ortho-para conversion is performed in parallel to the refrigeration, in order to minimize exergy losses (Knoche, Pg. 3, paragraph 26).
Claim 17 is rejected under 35 U.S.C. 103 as being unpatentable over Zhao et al. (US 20240418437), hereinafter Zhao.
Regarding claim 17, Zhao discloses a method of precooling a hydrogen feed stream (Fig. 2, purified gaseous hydrogen feed stream 100; Pg. 13, paragraph 91, FIG. 2 illustrates an embodiment of a hydrogen liquefaction system similar to FIG. 1. However, in the embodiment in FIG. 2, the first nitrogen circulation compressor 1800 may be combined with the integrated nitrogen compander 1600 on the same integral-gear 1020) comprising the steps of:
(a) cooling a high pressure nitrogen refrigerant stream and the hydrogen feed stream in a first heat exchanger or a first set of heat exchanger cores via indirect heat exchange with a low pressure gaseous recycle stream and a medium pressure gaseous recycle stream to yield a cooled, high hydrogen feed stream (Fig. 2, high-pressure circulation nitrogen stream 506, intermediate-pressure circulation gaseous nitrogen stream 500, low-pressure circulation gaseous nitrogen stream 544, first cold gaseous hydrogen stream 116, precooling main heat exchanger 606, pass 1-1, pass 1-2, pass 1-3, pass 1-5, pass 1-7; Pg. 6, paragraph 45, In embodiments, the first split gaseous hydrogen stream 114 may proceed to a pass 1-3 from the warm end of a precooling main heat exchanger 606, wherein the first split gaseous hydrogen stream 114 may exchange heat with cold passes 1-2, 1-4, 1-5 and 1-7; Pg. 8, paragraph 55, In embodiments, the high-pressure circulation nitrogen stream 506 may enter pass 1-1 from the warm end of the precooling main heat exchanger 606, wherein the high-pressure circulation nitrogen stream 506 may exchange heat with the cold stream passes 1-2, 1-4, 1-5 and 1-7. In embodiments, the side-stream warm nitrogen turbo-expander feed stream 508 may exit pass 1-1, wherein the side-stream warm nitrogen turbo-expander feed stream 508 may comprise a temperature of about 286K. Further, in embodiments the side-stream cold nitrogen turbo-expander feed stream 516 may also exit from pass 1-1, wherein the side-stream cold nitrogen turbo-expander feed stream 516 may comprise a temperature of about 174K);
(b) diverting a first portion of the high pressure nitrogen refrigerant stream from within the first heat exchanger or the first set of heat exchanger cores to yield a first diverted stream (Fig. 2, side-stream warm nitrogen turboexpander feed stream 508);
(c) expanding the first diverted stream in a warm turbine/expander to yield a warm exhaust stream that forms a part of the medium pressure gaseous recycle stream at a temperature colder than the first diverted stream (Fig. 2, warm nitrogen turbo-expander 1004, warm nitrogen turbo-expander discharge stream 510; Pg. 9-10, paragraph 62, Returning to the side-stream warm nitrogen turbo expander feed stream 508, in embodiments the side-stream warm nitrogen turbo-expander feed stream 508 may comprise a pressure of about 4410 kPa·G and a temperature of about 286K. In embodiments, the side-stream warm nitrogen turbo-expander feed stream 508 may enter the warm nitrogen turbo-expander 1004, wherein the side-stream warm nitrogen turbo-expander feed stream 508 may be expanded to a lower pressure of about 543 kPa ·G, which may result in a lower temperature of about 180K through a nearly isentropic expansion. In embodiments, the side-stream warm nitrogen turbo-expander feed stream 508 may exit the warm nitrogen turbo-expander 1004 as the warm nitrogen turbo expander discharge stream 510. In embodiments, the warm nitrogen turbo-expander discharge stream 510 may be routed into pass 1-2 of the precooling main heat exchanger 606, wherein the warm nitrogen turbo-expander discharge stream 510 may mix with the cold upcoming gaseous nitrogen 520 to provide cooling to the warm stream passes of the precooling main heat exchanger 606);
(d) diverting a second portion of the high pressure nitrogen refrigerant stream from within the first heat exchanger or the first set of heat exchanger cores to yield a second diverted stream, wherein the second diverted stream is at a temperature colder than the first diverted stream (Fig. 2, side-stream cold nitrogen turbo-expander feed stream 516; Pg. 20, paragraph 63, Returning to the side-stream cold nitrogen turbo expander feed stream 516, in embodiments the side-stream cold nitrogen turbo-expander feed stream 516 may comprise a pressure of about 4,395 kPa·G and a temperature of about 174K. In embodiments, the side-stream cold nitrogen turbo expander feed stream 516 may enter the cold nitrogen turbo-expander 1006, where the side-stream cold nitrogen turbo-expander feed stream 516 may be expanded to a lower pressure of about 560 kPa·G resulting in a lower temperature of about 105K through a nearly isentropic expansion. In embodiments, the side-stream cold nitrogen turbo-expander feed stream 516 may exit the cold nitrogen turbo-expander 1006 as the cold nitrogen turbo-expander discharge stream 518. In embodiments, the cold nitrogen turbo-expander discharge stream 518 may enter pass 1-2 of the precooling main heat exchanger 606, where the cold nitrogen turbo expander discharge stream 518 may mix with the intermediate-pressure thermosiphon nitrogen mixed stream 532 to provide cooling to the warm stream passes of the precooling main heat exchanger 606);
(e) expanding the second diverted stream in a cold turbine/expander to yield a cold exhaust stream that forms another part of the medium pressure gaseous recycle stream at a temperature colder than the second diverted stream (Fig. 2, cold nitrogen turbo-expander 1006, side-stream cold nitrogen turbo-expander feed stream 516; Pg. 20, paragraph 63, In embodiments, the side-stream cold nitrogen turbo expander feed stream 516 may enter the cold nitrogen turbo-expander 1006, where the side-stream cold nitrogen turbo-expander feed stream 516 may be expanded to a lowe