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 .
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) 1, 3-4, 7 is/are rejected under 35 U.S.C. 103 as being unpatentable over Zhao et al. (US PG Pub 20240418437), hereinafter referred to as Zhao and further in view of Knoche (US PG Pub 20230392859), hereinafter referred to as Knoche and Bauer (DE102013001970), hereinafter referred to as Bauer and Johnston et al. (US PG Pub 20160102908), hereinafter referred to as Johnston.
With respect to claim 1, Zhao teaches (Figure 2) a method for turndown of a nitrogen-based refrigeration system in a hydrogen precooling or hydrogen liquefaction system comprising the steps of:
(a) receiving a hydrogen feed stream at a prescribed volumetric flow (gaseous hydrogen stream 114 split form 200, paragraph 45);
(b) cooling 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, hydrogen feed stream (in heat exchanger 606 in heat exchange pass 1-2 the streams from 1004 and 1006 are used for cooling the hydrogen, paragraph 54 which is an intermediate pressure, and against 540 and 538 which is a lower pressure stream, paragraph 54);
(c) cooling a high-pressure nitrogen refrigerant stream in the first heat exchanger or first set of heat exchanger cores (high pressure nitrogen stream is cooled in 606, paragraph 54) and 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 (508 is a diverted portion of 606);
(d) 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 (508 is expanded in warm turbo-expander 1004 which would cool it and form a warm exhaust 510, paragraph 54);
(e) 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 (a second portion of the nitrogen stream at a colder point in the heat exchanger is removed at 516, paragraph 54);
(f) 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 (516 is expanded in cold turboexpander 1006 which would colder stream, paragraph 54);
(g) recycling the medium pressure gaseous recycle stream through the first heat exchanger or the first set of heat exchanger cores to cool the high-pressure nitrogen refrigerant stream and the hydrogen feed stream (518 and 510 are combined within the heat exchanger in 1-2, paragraph 61);
(h) expanding a third portion of the of the high-pressure nitrogen refrigerant stream in an expansion valve to yield a two-phase nitrogen stream (534, which is part of 500 is expanded in valve 1012 which produces two phase stream 536, paragraph 57);
(i) separating the two-phase nitrogen stream in a phase separator to yield a liquid nitrogen stream and the low pressure gaseous recycle stream (536 separator in 1014 into a vapor stream 538 and liquid stream 540, paragraph 57);
(j) recycling the low pressure gaseous recycle stream through the first heat exchanger or first set of heat exchanger cores to cool the high-pressure nitrogen refrigerant stream and the hydrogen feed stream (the vapor stream 538 is passed through 606 where it provides cooling in 1-4, paragraph 57); and wherein, in a first operating mode, the method further comprises the steps of: (k) directing a prescribed volumetric flow of the liquid nitrogen from the phase separator to heat exchanger and (l) precooling the cooled, hydrogen feed stream the liquid nitrogen to yield a precooled hydrogen feed stream at a temperature of less than or equal to 80 Kelvin (540 is used in 606 to further cool the stream to produce a hydrogen stream at 82 K, paragraph 54 which would render 80 K obvious as it has been held prima facie obvious that prior art ranges that do no overlap; but are close enough that one skilled in the art would have expected them to have the same properties, MPEP 2144.05 I, whereby they would both be supercritical streams with roughly the same properties cooled to a cryogenic temperature).
Zhao does a second heat exchanger or second set of heat exchanger cores where the liquid stream from the phase separator passes.
Knoche (Figure 1) teaches a similar heat exchange system to that of the pre-cooling system of Zhao including multiple expanders (64, 68) which provide a medium pressure stream (72) as well as an expansion valve (840 which sends a stream to a phase separator (88) which is used as a low pressure stream (92/96) before cycling the medium pressure stream through a series of heat exchangers (26a-26d) and the low pressure stream (92) through a second series of heat exchangers (26e-26f) followed by the first set of heat exchangers (paragraphs 32-37).
Therefore it would have been obvious to a person having ordinary skill in the art at the time the invention as filed to have based on the teaching of Knoche instead of utilizing a single heat exchanger in Zhao to have used a series of heat exchangers with the first series of heat exchangers (which would each have cores) starting from the warm side of the streams in the current heat exchanger and ending after where the cold exhaust turbine enters into heat exchanger and the second set of heat exchangers (which would each have cores) going from past the cold exhaust turbine entry point to where the coldest streams are in the current heat exchanger since it has been shown that a simple substitution of one known element (single heat exchanger) for another (multiple heat exchangers in series) to yield predictable results is obvious whereby utilizing multiple heat exchangers would allow for what would be common knowledge in the art of the heat exchangers being tailored individually to specific temperature conditions which would allow for a more efficient heat exchanger by allowing for the coldest heat exchangers to have a different design than the warmest.
Zhao does not teach and wherein, in a second operating mode, the method further comprises the steps of: (n) restricting the flow of liquid nitrogen from the phase separator to the second heat exchanger or second set of heat exchanger cores via a control valve; (o) accumulating an excess liquid nitrogen in the phase separator.
Bauer (Figures 1-2) teaches a similar heat exchanger and refrigeration system configuration to that of Zhao and additionally provides a control valve (V4) on the outlet of a phase separator (buffer tank D) so that when less gas is being sent to the heat exchanger the liquid can be blocked from leaving the tank and stored for use when needed (paragraphs 18-21).
Therefore, it would have been obvious to a person having ordinary skill in the art at the time the invention was filed to have a valve on the outlet line of the phase separator of Zhao and a mode where the valve is closed such that the flow of liquid nitrogen is restricted to the heat exchanger and the liquid nitrogen in the separator is accumulated based on the teaching of Bauer since it has been shown that combining prior art elements to yield predictable results is obvious whereby providing the control valve and restriction would allow for the refrigerant to only be used when required such that if less refrigeration is needed, the non-needed refrigerant can be stored for later use which would maximize efficiency by only using full refrigeration when necessary.
Zhao does not teach in the second operating mode still (m) restricting the flow of the hydrogen feed stream to the first heat exchanger or first set of heat exchanger cores such that the flow is less than the prescribed volumetric flow of the hydrogen feed stream to the first heat exchanger or first set of heat exchanger cores; (p) precooling the cooled, hydrogen feed stream in a second heat exchanger or second set of heat exchanger cores via indirect heat exchange with the restricted flow of liquid nitrogen to yield a precooled hydrogen feed stream at a temperature of less than or equal to 80 Kelvin.
Johnston (Figure 2) teaches a turn down condition that a control valve can be provided to control the flow of liquid refrigerant to a heat exchanger (paragraph 91) when the production of the cooled fluid is reduced (paragraph 29) such that during a first time normal operations are performed and in a second time turn down operations are performed when a reduction of product is produced and a third time when an increase is made to bring it back to the normal conditions and refrigerant is added back to the system until the original rates are restored (paragraphs 50-52, paragraph 98). During turn down conditions the same fluid is produced but only the production rate is reduced where the cooling duty is reduced to match production rate (paragraph 83).
Therefore, it would have been obvious to a person having ordinary skill in the art at the time the invention was filed to have based on the teaching of Johnston provide the modes of Zhao such that during the first mode normal operation is provided and then in the second mode reduced the flow of feed hydrogen gas to the heat exchanger system while maintaining the necessary overall cooling of the stream and using the control valve reduce the amount of liquid refrigerant passed from the phase separator to the second set of heat exchanger cores based on the teaching of Johnson as well as a third condition in which the flow rates are being increased until they are restored back to the first mode since it has been shown that combining prior art elements to yield predictable results whereby providing these modes of operation in this way would provide what would be common knowledge in the art of being able to adjust the system to conditions when there is a lesser demand for the hydrogen or under circumstances when it is less desirable to produce hydrogen at full rate (such as during more expensive electricity times) which would provide a more cost effective system by being able to match either ideal conditions of operation or desired conditions of operation on both the production and refrigeration sides of the heat exchanger. As the same fluid is produced in both conditions, with the only change being the rate of production, the refrigeration would be to the same point of 82K which would render 80 K obvious as it has been held prima facie obvious that prior art ranges that do no overlap; but are close enough that one skilled in the art would have expected them to have the same properties, MPEP 2144.05 I, whereby they would both be supercritical streams with roughly the same properties cooled to a cryogenic temperature.
With respect to claim 3, Zhao as modified teaches wherein in a third operating mode, the method further comprises the steps of: (m) increasing the flow of the hydrogen feed stream to the first heat exchanger or the first set of heat exchanger cores such that the flow is greater than the flow of the hydrogen feed stream to the first heat exchanger or the first set of heat exchanger cores in the second operating mode but less than the prescribed volumetric flow (during the third mode when the feed flow as modified is increased back to normal, there is a time that exists between the lowest flow and highest flow that would be met);
(n) releasing additional flow of liquid nitrogen from the phase separator to the second heat exchanger or the second set of heat exchanger cores via the control valve (during the third mode when refrigerant flow is increased back to normal there is a time that exists between the lowest flow and highest flow of refrigerant that meets this limitation);
and (p) precooling the cooled, hydrogen feed stream in the second heat exchanger or the second set of heat exchanger cores via indirect heat exchange with the additional flow of liquid nitrogen from the phase separator to yield a precooled hydrogen feed stream at a temperature of less than or equal to 80 Kelvin (the hydrogen production remains the same regardless of mode to the same point of 82K which would render 80 K obvious as it has been held prima facie obvious that prior art ranges that do no overlap; but are close enough that one skilled in the art would have expected them to have the same properties, MPEP 2144.05 I, whereby they would both be supercritical streams with roughly the same properties cooled to a cryogenic temperature).
With respect to claim 2, Zhao does not teach wherein the excess liquid nitrogen in phase separator is greater than 70% by volume of the nitrogen refrigerant used in the refrigeration circuit.
Bauer teaches that liquid stored in the buffer container (a phase separator) is done according to the requirement in the refrigeration circuit (paragraph 18). As it can be shown that the amount of refrigerant stored (the total excess liquid nitrogen in the phase separator) is a result effective variable that is optimized to achieve the refrigerant requirement by the claimed invention. Further, it appears that one of ordinary skill in the art would have had a reasonable expectation of success in modifying Zhao based on the teaching of Bauer as it only involves adjusting the dimension of a component disclosed to requirement adjustment (the amount of stored refrigerant). Therefore, it would have been one having ordinary skill in the art at the time the invention was filed to have the excess liquid nitrogen in the phase separator be greater than 70% by volume of the nitrogen refrigerant used in the refrigeration circuit as a matter of routine optimization since it has been held that “where the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955).
With respect to claim 4, Zhao as modified teaches (q) compressing the recycled low-pressure stream in a nitrogen feed compressor (low pressure nitrogen is compressed in 1800, paragraph 54);
(r) mixing the compressed, recycled low pressure stream with the recycled medium pressure stream to form a mixed recycle stream (medium refrigerant 500 is combined with compressed refrigerant 548 to form 502, paragraph 59);
and (s) further compressing the mixed recycle stream in a plurality of further compression stages (combined refrigerant is compressed in 1700, paragraph 65); and wherein the plurality of further compression stages comprises at least four further compression stages and the at least four further compression stages together with the warm turbine/expander and cold turbine/expander are operatively coupled to an integral gear machine having at least three pinions (the compressor 17000 can have four stages and is integrally geared with the two nitrogen expanders and 18000 as seen in the figure, paragraph 66 which means there would be four pinions, one for where each component connected).
With respect to claim 7, Zhao as modified teaches the step of treating the precooled hydrogen feed stream exiting the second heat exchanger or set of second heat exchanger cores with an ortho/para conversion catalyst vessel configured to treat the precooled hydrogen feed stream (cold hydrogen stream from 606 is passed to ortho-para converter 612, paragraph 47).
Claim(s) 5-6 is/are rejected under 35 U.S.C. 103 as being unpatentable over Zhao/Knoche/Bauer and further in view of Prosser (US PG Pub 20220404094), hereinafter referred to as Prosser
With respect to claim 5, Zhao as modified teaches wherein the warm exhaust stream is at a temperature in the range of 150 K to 185 K (180 K, paragraph 62).
Zhao as modified does not teach the first diverted stream is less than or equal to about 40% by volume of the high-pressure nitrogen refrigerant stream.
Prosser teaches that in a refrigeration system with a warm and cold turbine and liquid nitrogen used from the cycle as a refrigerant that the warm turbine only needs about 10% to 20% of the cold turbine flow (paragraph 39). While this does not teach specifically the amount of the warm, it is less than 20% of the overall flow, because if the cold turbine flow was 99% of the high-pressure nitrogen stream it would then only constitute 20% of the overall flow.
Therefore it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to have operated Zhao such that the first diverted stream is less than or equal to about 40% by volume of the high-pressure nitrogen refrigerant stream as applicant appears to have placed no criticality on the claimed range (indicating it is about 40%) and since it has been held that “[i]n 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).
With respect to claim 6, Zhao as modified teaches wherein the cold exhaust stream is at a temperature in the range of 85 Kelvin and 105 Kelvin (105 K, paragraph 61).
Zhao as modified does not teach wherein the second diverted stream is greater than the volume of the first diverted stream
Prosser teaches that in a refrigeration system with a warm and cold turbine and liquid nitrogen used from the cycle as a refrigerant that the warm turbine only needs about 10% to 20% of the cold turbine flow as the demand for the warm turbine is lower (paragraph 39).
Therefore, it would have been obvious to a person having ordinary skill in the art at the time the invention was filed to have based on the teaching of Prosser provided to have provided the second diverted stream in Zhao with greater volume of the first diverted stream since the demand for the refrigeration level of the warm turbine is lower.
Claim(s) 8-12, 15-16 is/are rejected under 35 U.S.C. 103 as being unpatentable over Zhao and further in view of Bauer and Japhet.
With respect to claim 8, Zhao teaches (Figure 2) a refrigeration system for precooling of hydrogen and liquefaction of nitrogen, the refrigeration system comprising: an integral gear machine comprising a drive assembly (1020, paragraph 54), a bull gear (1020 which is the common integral gear, paragraph 66 would be a bull gear), and a plurality of pinions arranged to drive four or more refrigerant compression stages of the refrigeration system and for receiving work produced by the at least two turbine/expanders of the refrigeration system (compressor 1700 which has four stages, and expanders 1004 and 1600 are connected to the integral-gear, paragraph 66 which connection points would be plurality of pinions);
a refrigeration circuit configured to circulate a plurality of nitrogen streams including a high-pressure nitrogen refrigerant stream (high pressure nitrogen at 506 which produces multiple nitrogen streams including 540 and 508 used for cooling against hydrogen at 114 in heat exchanger 606, paragraphs 45, 54);
an expansion valve disposed in the refrigeration circuit configured for expanding the high-pressure nitrogen refrigerant stream to yield a two-phase nitrogen stream (1012, paragraph 54);
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 (1014 which produces liquid 540 and gas 538, paragraph 54);
a first heat exchanger or a first set of 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 (506 and 114 are cooled in heat exchanger 606 against streams from 1004, 1006 and 538, paragraph 54);
configured precool the cooled hydrogen feed stream to a temperature of less than or equal to 80 K via indirect heat exchange with a liquid nitrogen stream received from the phase separator (the liquid 540 is used to cool the hydrogen to 82 K, paragraph 54, which would render 80 K obvious as it has been held prima facie obvious that prior art ranges that do no overlap; but are close enough that one skilled in the art would have expected them to have the same properties, MPEP 2144.05 I, whereby they would both be supercritical streams with roughly the same properties cooled to a cryogenic temperature).
Zhao does not teach a second heat exchanger or the second set of heat exchange cores disposed within the refrigeration circuit and configured to receive the cooled hydrogen feed stream from the first heat exchanger or set of first heat exchange cores.
Knoche (Figure 1) teaches a similar heat exchange system to that of the pre-cooling system of Zhao including multiple expanders (64, 68) which provide a medium pressure stream (72) as well as an expansion valve (840 which sends a stream to a phase separator (88) which is used as a low pressure stream (92/96) before cycling the medium pressure stream through a series of heat exchangers (26a-26d) and the low pressure stream (92) through a second series of heat exchangers (26e-26f) followed by the first set of heat exchangers (paragraphs 32-37).
Therefore it would have been obvious to a person having ordinary skill in the art at the time the invention as filed to have based on the teaching of Knoche instead of utilizing a single heat exchanger in Zhao to have used a series of heat exchangers with the first series of heat exchangers (which would each have cores) starting from the warm side of the streams in the current heat exchanger and ending after where the cold exhaust turbine enters into heat exchanger and the second set of heat exchangers (which would each have cores) going from past the cold exhaust turbine entry point to where the coldest streams are in the current heat exchanger since it has been shown that a simple substitution of one known element (single heat exchanger) for another (multiple heat exchangers in series) to yield predictable results is obvious whereby utilizing multiple heat exchangers would allow for what would be common knowledge in the art of the heat exchangers being tailored individually to specific temperature conditions which would allow for a more efficient heat exchanger by allowing for the coldest heat exchangers to have a different design than the warmest.
Zhao does not teach a control valve in fluid communication with the phase separator and configured to control the liquid nitrogen exiting the phase separator to a second heat exchanger or set of second heat exchange cores in response to the flow of the hydrogen feed stream to the first heat exchanger or set of first heat exchange cores.
Bauer (Figures 1-2) teaches a similar heat exchanger and refrigeration system configuration to that of Zhao and additionally provides a control valve (V4) on the outlet of a phase separator (buffer tank D) so that when less gas is being sent to the heat exchanger the liquid can be blocked from leaving the tank and stored for use when needed (paragraphs 18-21).
Therefore, it would have been obvious to a person having ordinary skill in the art at the time the invention was filed to have a valve on the outlet line of the phase separator of Zhao able to operate based on changes to the hydrogen feed flow since it has been shown that combining prior art elements to yield predictable results is obvious whereby providing the control valve and restriction would allow for the refrigerant to only be used when required such that if less refrigeration is needed, the non-needed refrigerant can be stored for later use which would maximize efficiency by only using full refrigeration when necessary.
Zhao does not teach wherein the phase separator is sized to hold at least 70% by volume of the nitrogen in the refrigeration system.
Japhet teaches that a phase separator sizing is to separate the respective liquid and gaseous phase by gravity and difference in mass (Column 3, lines 60-65).
As such, it can be shown by Japhet that the sizing of a phase separator is a result effective variable that is optimize to ensure the separation of the respective liquid and gaseous phase by gravity and difference in mass. Further, it appears that one of ordinary skill in the art would have had a reasonable expectation of success in modifying Zhao based on the teaching of Japhet to have a volume (which is size) within the claimed range, as it involves only adjusting the dimension of a component disclose to require adjustment (size). Therefore, it would have been one having ordinary skill in the art at the time the invention was filed to have configured the phase separator of Zhao to be capable of holding greater than 70% of the nitrogen refrigerant used in the refrigeration circuit as a matter of routine optimization since it has been held that “where the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955).
With respect to claim 9, Zhao as modified teaches the four or more refrigerant compression stages comprise a nitrogen feed compressor (first compressor), a nitrogen recycle compressor (first stage of 1700), a cold compressor ( and a booster compressor, a low-pressure nitrogen recycle stream to form a nitrogen refrigerant stream and direct the nitrogen refrigerant stream to the nitrogen feed compressor (low pressure nitrogen is compressed in 1800, paragraph 54);
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 (nitrogen stream 548 mixes with low pressure nitrogen 500 which are then passed to compressor the first stage of 1700, paragraph 54, paragraph 60);
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 (after the first stage refrigerant passe to 1004 and 1006).
Zhao as modified does not teach the refrigeration circuit is further configured to mix a nitrogen feed stream with the low-pressure nitrogen recycle stream to form a nitrogen refrigerant stream.
Examiner takes official notice that it would have been obvious to a person having ordinary skill in the art at the time the invention to have mixed a nitrogen feed stream with the low-pressure nitrogen recycle stream in order to provide a make-up stream of refrigerant to increase the inventory when more refrigerant is needed for the system either because more refrigerant is required for operation or to account for leaking of refrigerant. As applicant has not timely traversed this official notice it is considered admitted prior art.
With respect to claim 10, Zhao as modified wherein the hydrogen feed stream further comprises comprising a high pressure hydrogen stream at a pressure of greater than or equal to about 40 bar(a) and that is circulated through the refrigeration circuit and cooled in the first heat exchanger or set of first heat exchange cores to a temperature of about 80 Kelvin (hydrogen at 112 at a pressure of up to 4000 KPaG, paragraph 37, which is above 40 bar(a) from 114, to 82 K, paragraph 54 which is about 80 K).
With respect to claim 11, Zhao as modified teaches further comprising one or more hydrogen return streams that are circulated through the refrigeration circuit and the first heat exchanger or set of the first heat exchange cores to cool the high-pressure nitrogen refrigerant stream and the hydrogen feed stream (hydrogen stream that is being returned back through the heat exchangers 218 is used for cooling 606 against the hydrogen stream in 1-3 and nitrogen in 1-1, paragraph 81).
With respect to claim 12, Zhao as modified teaches wherein the at least two turbine/expanders include 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 (1004 and 1006 receives diverted portions of the high pressure nitrogen 508, 510, paragraph 54).
With respect to claim 15, Zhao as modified teaches further comprising an ortho/para conversion catalyst vessel configured to treat the precooled hydrogen feed stream exiting the second heat exchanger or the second set of heat exchanger cores (cold hydrogen stream from 606 is passed to ortho-para converter 612, paragraph 47).
With respect to claim 16, Zhao as modified teaches wherein the second heat exchanger or the second set of heat exchanger cores is further configured to re-cool the treated precooled hydrogen feed stream to a temperature less than or equal to 80 Kelvin (after being converted the stream is cooled again against the liquid stream and thus in the part that would be the second heat exchanger cores back to 82 K, paragraph 47, which would render 80 K obvious as it has been held prima facie obvious that prior art ranges that do no overlap; but are close enough that one skilled in the art would have expected them to have the same properties, MPEP 2144.05 I, whereby they would both be supercritical streams with roughly the same properties cooled to a cryogenic temperature).
Claim(s) 13-14 is/are rejected under 35 U.S.C. 103 as being unpatentable over Zhao/Bauer/Japhet and further in view of Prosser.
With respect to claim 13, Zhao as modified teaches wherein the first diverted and is expanded in the warm turbine/expander to yield a warm exhaust stream at a temperature in the range of 150 Kelvin to 185 Kelvin (expanded stream 510 formed of 508 is at 180 K, paragraph 61); and wherein the warm exhaust stream is warmed to ambient temperatures in the first heat exchanger or the first set of heat exchanger cores (510 is mixed in passage 1-2 and warmed up to 311 K, paragraph 61).
Zhao as modified does not teach the first diverted stream is less than or equal to about 40% by volume of the high-pressure nitrogen refrigerant stream.
Prosser teaches that in a refrigeration system with a warm and cold turbine and liquid nitrogen used from the cycle as a refrigerant that the warm turbine only needs about 10% to 20% of the cold turbine flow (paragraph 39). While this does not teach specifically the amount of the warm, it is less than 20% of the overall flow, because if the cold turbine flow was 99% of the high-pressure nitrogen stream it would then only constitute 20% of the overall flow.
With respect to claim 14, Zhao as modified teaches wherein the second diverted stream and is expanded in the cold turbine/expander to yield a cold exhaust stream at a temperature in the range of 85 Kelvin and 105 Kelvin (518 is formed of expanded 516 and is at 105 K, paragraph 61); and wherein the cold exhaust stream is warmed to ambient temperatures in the first heat exchanger or the first set of heat exchanger cores (518 is mixed in passage 1-2 and warmed up to 311 K, paragraph 61).
Zhao as modified does not teach wherein the second diverted stream is greater than the volume of the first diverted stream.
Prosser teaches that in a refrigeration system with a warm and cold turbine and liquid nitrogen used from the cycle as a refrigerant that the warm turbine only needs about 10% to 20% of the cold turbine flow as the demand for the warm turbine is lower (paragraph 39).
Therefore, it would have been obvious to a person having ordinary skill in the art at the time the invention was filed to have based on the teaching of Prosser provided to have provided the second diverted stream in Zhao with greater volume of the first diverted stream since the demand for the refrigeration level of the warm turbine is lower.
Response to Arguments
Applicant's arguments filed 9/8/2025 have been fully considered but they are not persuasive.
Applicant argues page 10 that “the Office action incorrectly assumes that precooling a hydrogen feed stream to a temperature equal to or less than 80 K is obvious” and then argues that there is criticality between the temperatures of 82 Kelvin and <= 80 Kelvin because of a difference in the refrigeration that would be provided by the two different temperatures with respect to the refrigeration loads. This is not persuasive.
Applicant has not provided any evidence of criticality. In order to provide a showing of criticality it must be shown that “the claimed range achieves unexpected results relative to the prior art range” and that “the applicant has the burden of establishing his position by a proper showing of the facts upon which he relies” MPEP 2144.05 III A. A mere statement that the limitation is critical with an explanation of the alleged reason for criticality is not sufficient without evidence to show such criticality. The arguments provided do not amount to a necessary showing of criticality as they are not provided with facts or evidence to back up such arguments.
Applicant argues that Knoche is mischaracterized as the multiple expanders, and other components are all associated with the hydrogen liquefaction circuit and not the pre-cooling arrangement and as such “Knoche does not teach or disclose step (h) of the present claim nor step (l) of the present claim and Knoche is a closed loop arrangement compared to applicants open loop configuration. This is not persuasive.
Knoche provides a teaching of a system similar to that of the claimed invention through the use of multiple heat exchangers to provide the overall heat exchanger configuration. Although Knoche does not refer to the later heat exchangers (26a-26d) as pre-cooling heat exchangers, they can still be considered pre-cooling as they are upstream of the liquefaction heat exchangers. Thus, when looking at the system of Zhao, one of ordinary skill in the art would consider it obvious to modify the existing heat exchanger of Zhao into multiple heat exchangers, all of which together provide the pre-cooling and all of which receive the claimed refrigerant streams. Knoche is only used to show the use of multiple heat exchanges, and that Knoche has a closed loop configuration does not render it any less obvious of a teaching as applied.
Applicant argues, pages 12-13 that in regards to Bauer that “Bauer is not related to hydrogen pre-cooing system but rather to natural gas liquefaction” and provides features that contrast the claimed invention including removing the nitrogen refrigerant when it has a temperature below its critical temperature and expanding of the removed refrigerant and does not store it in a separate buffer container and as such “Bauer actually teaches away from the present invention”. This is not persuasive.
That Bauer is related to a different fluid for liquefaction than that of the claimed invention does not render the teachings provided by Bauer any less obvious. Bauer is used to provide a teaching of using a phase separator (buffer tank of Bauer is a phase separator) to block liquid from entering into a refrigerant circuit when the refrigeration requirement is not needed by the refrigerant circuit (paragraph 18). That Bauer does this for a different reason or expands the refrigerant does not render the teaching any less obvious. What Bauer is teaching is that a phase separator can be used to store liquid refrigerant in excess of what is necessary when the excess refrigerant is not needed. As Zhao already has a phase separator as in the claimed invention, it would be obvious to have modified Zhao based on the teaching of Bauer to arrive at the invention as claimed.
In regards to the previous omission of the Johnston, such reference has been provided above in the rejection.
Applicant argues that the “phase separator in the present system” being “designed to be oversized and capable of holding greater than 70% of the nitrogen refrigerant used in the refrigeration circuit in an effort to avoid using separation storage tanks or buffer tank” is not a result effective variable”. This is not persuasive.
Applicant has provided no reason as to why it is not a result effective variable, only stating that the phase separator is designed by oversized to achieve a specific result, which by definition makes it a result effective variable, it is sized to a specific size so that it is sufficient to achieve the necessary task. Further, Japhet clearly teaches that the size of a phase separator is a result effective variable, and that there is a different reasoning as to why the size is provide does not render the limitation any less obvious.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to BRIAN M KING whose telephone number is (571)272-2816. The examiner can normally be reached Monday - Friday, 0800-1700.
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/BRIAN M KING/Primary Examiner, Art Unit 3763