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
Applicant’s amendment filed 22 June 2026 has been considered. It is acknowledged that claim 1 has been amended and claims 6 and 8-12 have been cancelled by Applicant. Accordingly, Claims 1-2, 4-5, and 7 are under pending in this application.
Response to Arguments
Applicant's arguments filed 22 June 2026 have been fully considered but they are not persuasive. The respective arguments are addressed below:
Applicant argues that neither Selstam nor Kim discloses or suggests directly recirculating the off-gas to the plasma reactor. Examiner does not find this persuasive, and reminds Applicant that one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986). In this rejection, Selstam taught the plasma reactor while Kim taught recirculation, and the obviousness of the combination was explained in the claim 1 rejection. The combination of the prior art in such a way was not acknowledged by Applicant. Accordingly, Examiner encourages Applicant to see the claim 1 rejection where the combination of these features is explained.
Applicant argues that the newly added amendment claiming, “40% volume to 90% volume of the first off gas discharged from the first adsorber is recirculated” would not have been obvious over the prior art. Examiner respectfully disagrees, as Kim discloses off gas recirculation (see claim 1 rejection), and the exact volumetric ratio of recirculated gas is a results effective variable, the newly claimed range of which does not present any new or unexpected results. Applicant presents evidence of benefits of recirculation, however this evidence does not establish that the claimed range is critical. The comparative data compare embodiments employing off-gas recirculation (50vol% and 83vol%) only to an embodiment employing no off-gas recirculation. The data therefore demonstrate, at most, that recirculating off gas improves efficiency relative to not recirculating off-gas. They do not demonstrate that the claimed range of 40-90 vol% achieves unexpected results relative to other recycle amounts or that the endpoints of the claimed range are critical. Accordingly, the evidence is insufficient to overcome the conclusion hat selecting a recycle percentage within the claimed range would have been an obvious matter of routine optimization of a known operating parameter.
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.
Claims 1-2, 4, and 7 are rejected under 35 U.S.C. 103 as being unpatentable over Selstam et al. (US-20140364517-A1), hereinafter “Selstam”, in view of Kim et al. (US-20100254893-A1), hereinafter “Kim” and Eurlings (US-20230303393-A1).
Regarding Claim 1, Selstam discloses an apparatus for producing a hydrogen gas (convert a portion of the syngas to… H-2; see e.g. [0012]), the apparatus comprising a plasma reactor configured to generate a hydrogen containing gas from a hydrocarbon containing gas through plasma-based pyrolysis (pyrolyzing a carbon source by plasma to form syngas; reacting a portion of the formed syngas… to H-2; see e.g. [0012]), a first heat exchanger (heat exchanger 106; see e.g. [0042]) configured to exchange heat between the hydrocarbon containing gas of a low temperature (syngas feed 110, optionally preheated by optional heat exchanger 106; see [0043] and Fig. 1 Parts 106 and 110; the fact that the syngas, or hydrocarbon containing gas, is being heated by the heat exchanger indicates that it is the low temperature stream in the exchanger that is receiving heat) and a low purity hydrogen gas of a high temperature (see e.g. [0042] – [0043], and Fig. 1 Parts 106 and 116) and a second heat exchanger (see e.g. [0043] and Fig. 1, part 106) configured to exchange heat between the hydrocarbon containing gas of a low temperature before removal of impurities (a heat exchanger 106 may be placed… to be used as the heat exchanger upstream of separator 108; see [0043] and Fig. 1 Parts 106 and 107), and the low-purity hydrogen gas of a high temperature that exchanged heat in the first exchanger (heat exchanger 106 may be placed downstream of water gas shift reactor 115… be used to maintain products of the reactor 115 at a desired temperature; see e.g. [0043] and Fig. 1 Parts 106 and 116). Regarding the limitations of the hydrocarbon containing gas being of a low temperature, and the hydrogen gas being of a high temperature, Selstam discloses that the syngas feed leaving the gasifier (analogous to the hydrocarbon containing gas) may be in the range of 100oC – 2000oC (see [0042]) and the shift reaction may occur in a low temperature reactor or a high temperature reactor (see [0043]), where the stream resulting from the shift reactor is analogous to the low purity hydrogen stream. The heat exchanger 106, which exchanges heat between these two streams, as previously cited, is therefore capable of exchanging heat in either direction, and the process is capable of either stream being the high temperature stream or the low temperature stream. Further, the relative temperature of each stream is a functional limitation that does not further define the structure of the apparatus/system, but merely sets forth a manner of operating the apparatus. The Courts have held that apparatus claims must be structurally distinguishable from the prior art in terms of structure, not function. See In re Danley, 120 USPQ 528, 531 (CCPA 1959); and Hewlett-Packard Co. V. Bausch and Lomb, Inc., 15 USPQ2d 1525, 1528 (Fed. Cir. 1990) (see MPEP §§ 2114 and 2173.05(g)). The manner of operating an apparatus does not differentiate an apparatus claim from the prior art, if the prior art apparatus teaches all of the structural limitations of the claim. See Ex Parte Masham, 2 USPQ2d 1647 (BPAI 1987).
Selstam discloses a syngas feed being mixed with steam to form a mixture of steam, H2, and CO, which then enters a water gas shift reactor where the steam and CO react to form CO2 and H2. This effectively alters the ratio of H2 to CO such that the ratio is raised. This operation may be controlled to produce a syngas having a desired H2:CO ratio up to, for example, 4:1 (see e.g. [0043]). The instant application specifies the separator as separating “side products including the low purity hydrogen gas and carbon from the hydrogen containing gas”. The exact components and component ratios of the low purity hydrogen gas are not disclosed in the instant application, and therefore the low purity hydrogen gas is interpreted as hydrogen gas that contains a significant amount of non-hydrogen components. The syngas that is leaving the water gas shift reactor taught by Selstam is a low purity hydrogen gas. Additionally, the side products leaving the separator of the instant application are not specified as having any further use. The stream is labeled as “g” and is not used anywhere else in the process. This indicates that the separator’s primary function is to further purify the hydrogen containing gas into a “low purity hydrogen gas”. So, while the water gas shift reactor is not physically identical to a separator, in this scenario, it is producing the same function as the separator claimed in the instant application, and is therefore interchangeable and analogous to the separator.
Selstam does not explicitly teach a desulfurizer, adsorber, and an off-gas recirculation. However, Kim discloses a desulfurizer configured to desulfurize a hydrocarbon containing gas (see e.g. [0024]); and a first adsorber configured to separate the low-purity hydrogen gas that exchanged heat in the second heat exchanger into a first high-purity hydrogen gas and a first off gas (see e.g. [0024], [0038] and Fig. 1), through adsorption, wherein at least a portion of the off gas discharged from the first adsorber is recirculated (see e.g. Fig. 1). Neither Selstam nor Kim teach the off-gas recirculation as being recirculated to the plasma reactor. However, Kim teaches the off gas being recirculated to the reformer/burner (see e.g. Fig. 1), which is performing a function analogous to that of the plasma reactor disclosed by Selstam. Therefore, when Selstam is modified by Kim, it would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention that the recirculation of off gas taught by Kim would be directed to the plasma reactor taught by Selstam. Kim further discloses a cooler configured to cool the low-purity hydrogen gas that exchanged heat in the second heat exchanger (see e.g. Fig. 1 and [0037]). This would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention because doing so brings the low-purity hydrogen gas down to the temperature of the PSA unit (see e.g. [0037]).
Regarding the limitation that 40% volume to 90% volume of a total volume of the off gas is recirculated, as discussed above, Kim discloses recirculating at least a portion of the first off-gas from the adsorber. The percentage of the off-gas selected for recirculation constitutes a result-effective operating parameter because the amount of recycled gas predictably affects reactor operating conditions such as reactant composition, energy consumption, and the amount of feedstock consumption. It would have been obvious to a person of ordinary skill in the art to optimize the amount of recycled off gas through routine experimentation to achieve the desired operating characteristics. Selecting a recycle amount within the claimed range of 40% volume and 90% volume therefore amounts to the optimization of a known result effective variable and would have been obvious absent evidence that the claimed range is critical or produces unexpected results.
The combination of Selstam and Kim does not explicitly disclose a first compressor configured to compress the low-purity hydrogen gas cooled in the cooler. However, using a compressor in conjunction with a cooler is a very commonly employed technique as taught by Eurlings (see e.g. [0081]). Selstam and Eurlings are both considered to be analogous to the claimed invention because they are in the same field of hydrogen production. Therefore, it would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention to have modified Selstam by incorporating the teachings of Eurlings and using a compressor in conjunction with a cooler. This would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention because doing so can provide a multistage intercooled compression (see e.g. [0081]).
Eurlings further discloses an adsorber receiving gas discharged from the first compressor (see compressor 423 in Fig. 5, then stream 401 enters 510 in Fig. 6, then stream 501 enters adsorption units in Fig. 7).
The instant application claims 2 heat exchangers, both of which exchange heat using the low purity hydrogen gas. The first heat exchanger is disposed after the desulfurizer and exchanges heat between the low purity hydrogen gas and the desulfurized hydrocarbon containing gas. The second heat exchanger is disposed before the desulfurizer and exchanges heat between the low purity hydrogen containing gas exiting the first heat exchanger and the hydrocarbon containing gas, prior to its desulfurization. While the combination of Selstam and Kim does not explicitly teach this specific heat exchanger placement, it would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention. The instant application claims the use of the low purity hydrogen gas to heat the feed hydrogen containing gas before treatment of impurities (desulfurization) and after treatment of impurities. Selstam teaches the low purity hydrogen gas exchanging heat with the syngas feed prior to the feed entering a separator, where condensed water (an impurity) is removed (see e.g. [0042]). Then, immediately after the condensed water is removed, the syngas stream exchanges heat with the low purity hydrogen gas again, in the same heat exchanger (see e.g. [0043]). When Selstam is modified by the teachings of Kim, it would have been obvious to a person of ordinary skill in the art before the filing date of the claimed invention to dispose the desulfurizer in the same relative position as the separator for condensed water removal taught by Selstam, as they are both operating to remove impurities. The desulfurizer being disposed in the position described above would result in the low-purity hydrogen gas exchanging heat with the hydrocarbon containing gas of a low temperature introduced into the desulfurizer. Modified Selstam still only uses one heat exchanger for these specific functions, however it would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention to separate the heat exchanger (106) taught by Selstam, (see In reDulberg, 289 F.2d 522, 523, 129 USPQ 348, 349 (CCPA 1961)) into two separate heat exchangers if the heating requirements of each stream cannot be met with a single exchanger. This is a matter of routine experimentation/optimization.
Selstam and Kim are both considered to be analogous to the claimed invention because they are in the same field of hydrogen production. Therefore, it would have been obvious to a person of ordinary skill prior to the effective filing date of the claimed invention to have modified Selstam by incorporating the teachings of Kim and providing a desulfurizer and an adsorber, and recirculating the off-gas. Doing so would remove sulfur impurities from the hydrocarbon feed (see e.g. Kim [0027]), produce high purity hydrogen (see e.g. Kim [0038]), and provide fuel for other components in the process (see e.g. Kim [0039]), respectively.
Regarding Claim 2, Selstam, Kim, and Eurlings together disclose the apparatus of claim 1.
The combination of Selstam and Kim does not explicitly teach an additional heat exchanger, between the first and second heat exchangers, configured to exchange heat between the low purity hydrogen gas that exchanged heat in the first exchanger and at least a portion of the first off gas discharged from the first adsorber. However, Eurlings discloses an additional heat exchanger configured to exchange heat between the cleaned syngas (analogous to the low purity hydrogen stream) and an off-gas (see [0082]). The placement of the heat exchanger between the first and second heat exchanger is not explicitly taught, but would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention to try. There are a finite number of physical places where the third heat exchanger could have been disposed relative to the first and second exchangers, and it would have been obvious to a person of ordinary skill in the art to dispose the third heat exchanger in a location optimal for efficient heat exchange.
Selstam and Eurlings are both considered to be analogous to the claimed invention because they are in the same field of hydrogen production. Therefore, it would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention to have modified Selstam by incorporating the teachings of Eurlings and exchanging heat between an off gas and the low purity hydrogen stream. Doing so can increase the hydrogen content (see e.g. Eurlings [0038]).
Regarding Claim 4, Selstam, Kim, and Eurlings together disclose the apparatus of claim 1.
Selstam and Kim do not explicitly teach a second compressor. However, Eurlings discloses a second compressor configured to compress recirculated syngas (see e.g. [0074]). Eurlings does not specifically teach using the second compressor to compress recirculated off gas. However, as explained in the claim 1 rejection, it would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention to direct the recirculated off gas taught by Kim to the plasma reactor taught by Selstam, and because Eurlings is using the second compressor to compress recirculated gas, it would have been obvious to a person of ordinary skill in the art, prior to the effective filing date of the claimed invention, when modifying Selstam/Kim that this compressor would compress the recirculated off gas. This would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention because the compressor acts as a conveying means to convey the recycled gas toward the unit intended to receive the recycle stream (see e.g. Eurlings [0080]).
Regarding Claim 7, Selstam, Kim, and Eurlings together disclose the apparatus of claim 1. Kim further discloses the first adsorber performing pressure swing adsorption (PSA) (see e.g. [0024]). This would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention because PSA is generally employed by those skilled in the art in order to separate hydrogen, and is a method of producing high-purity hydrogen by absorbing and removing impurities from highly-concentrated hydrogen-containing gas (see e.g. Kim [0038]).
Claim 5 is rejected under 35 U.S.C. 103 as being unpatentable over Selstam et al. (US-20140364517-A1), hereinafter “Selstam”, in view of Kim et al. (US-20100254893-A1), hereinafter “Kim” and Eurlings (US-20230303393-A1) and further in view of Baker Hughes (5 things you should know about flaring).
Regarding Claim 5, Selstam, Kim, and Eurlings together disclose the apparatus of claim 4. Eurlings further discloses a flare configured to burn and discharge the remaining portions of the syngas (analogous to the off-gas), which was not introduced into the second compressor (see e.g. [0076] and Fig. 5). Eurlings does not explicitly teach the flare being configured to “burn and discharge”, however it is very well known in the art that this is what a flare does. Sending gas to a flare is a direct and explicit indication that the gas is being burned and discharged in said flare. It is well known in the art that using a flare decreases the methane output of a facility, and reduces the impact that facility is having on the environment, from a carbon-emissions standpoint (see e.g. Baker Hughes, Points 3 and 4). This motivation would have made the addition of a flare obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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/A.L.K./Examiner, Art Unit 1774
/CLAIRE X WANG/Supervisory Patent Examiner, Art Unit 1774
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