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 .
Status of the Claims
This is a non-final Office action in response to the Applicant’s arguments and amendments filed on 03/30/2026. Claims 1-21 are pending in the current office action. Claims 1, 4-6, and 20-21 were amended by Applicant.
Status of the Rejection
The objections to claims 3 and 20 are withdrawn in view of Applicant’s amendments.
The rejections of claims 1-21 under 35 U.S.C. § 112(b) are withdrawn in view of Applicant’s amendments.
The rejections of claims 1-21 under 35 U.S.C. § 103 are withdrawn upon consideration of Applicant’s arguments.
New grounds of rejection under 35 U.S.C. § 112(a) due to inclusion of new matter were identified.
New grounds of rejection under 35 U.S.C. § 112(b) were identified.
New rejections under 35 U.S.C. § 102(a)(1) and 35 U.S.C. § 103 are established based on further consideration of the prior art.
Claim Interpretation
The instant application includes the use of the unit “barg”, which is a unit of gauge pressure, in the claims and/or specification. It is understood by persons of ordinary skill in the art that the gauge pressure indicates the pressure in a system in excess of atmospheric pressure (approximately 1 bar at sea level). For example, a pressure of 1 barg is approximately equivalent to a pressure of 2 bar at sea level. See excerpt below from Towler, et al. (Chemical Engineering Design - Principles, Practice and Economics of Plant and Process Design (2nd Edition) - 1.7 Systems of Units pp. 21 (2013) Elsevier).
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Claim Rejections - 35 USC § 112
The following is a quotation of the first paragraph of 35 U.S.C. 112(a):
(a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention.
Claims 10 and 11 are rejected under 35 U.S.C. 112(a) as failing to comply with the written description requirement due to the inclusion of new matter. 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, at the time the application was filed, had possession of the claimed invention.
Regarding claim 10, claim 10 recites the limitation “a second stream of hydrogen mixed with steam is passed through the feed/effluent heat exchanger prior to being further cooled down by generated high pressure steam” (emphasis added). The specification as originally filed is not considered to provide support for this limitation.
Specifically, the original specification reads “The stream of hydrogen mixed with steam is then passed through the above-mentioned feed/effluent heat exchanger Hex1 prior to being further cooled down by generating additional high pressure steam.” (p. 9 lines 9-18, emphasis added). I.e., the specification describes using the hot cathode effluent to make steam, while the claim language requires a hot stream of hydrogen and steam to be cooled by pre-existing high pressure steam, a process materially different from cooling the second stream with steam as currently claimed.
It is therefore considered that the limitation “a second stream of hydrogen mixed with steam is passed through the feed/effluent heat exchanger prior to being further cooled down by generated high pressure steam” is new matter not supported by the specification as originally filed. A rejection under 35 U.S.C. § 112(a) as failing to comply with the written description requirement is therefore appropriate.
Regarding claim 11, claim 11 depends from claim 10, and therefore includes the new matter described in claim 10. A rejection under 35 U.S.C. § 112(a) as failing to comply with the written description requirement is therefore appropriate.
Claims 2-3 and 5-11 are rejected under 35 U.S.C. 112(b) as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor regards as the invention.
Regarding claim 2, Claim 2 recites the limitation "the electrolysis units are" in line 1. There is insufficient antecedent basis for this limitation in the claim. Specifically, claim 1, from which claim 2 depends, recites “an electrolysis unit or the first of a series of electrolysis units”, rather than “electrolysis units”. It is therefore unclear whether or not claim 2 is intended to require a series of electrolysis units.
Claim 2 is therefore indefinite.
Examiner recommends amending claim 2 to recite “the electrolysis unit or electrolysis units is/are” or “wherein the electrolysis unit is the first of a series of electrolysis units and the electrolysis units are”.
Regarding claims 3 and 5-11, these claims depend from claim 2, and therefore incorporate the indefinite language of claim 2. Claims 3 and 5-11 are therefore indefinite.
Claim Rejections - 35 USC § 102
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claims 1-6, 12-15, 18, and 20 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Braun (US Pat. Pub. 2014/0272734) as evidenced by Rackley (“Carbon Capture and Storage - 3.1.5 Rankine Steam Cycle.” (2010) Elsevier) and, in the case of claims 4-6, Reytier (US Pat. Pub. 2016/0053388).
Regarding claim 1, Braun teaches a method for generating synthesis gas containing hydrogen, carbon monoxide or mixtures of hydrogen, carbon monoxide and carbon dioxide by electrolysis (para. 3),
said method comprising feeding steam (“The polished feed stream may be combined with hydrogen and steam … The preheated polished feed stream may be fed into the SOEC 210 at the cathode 212” Fig. 2 and para. 58) and compressed air (“Air exiting compressor 220 may … be provided to the SOEC 210 at the anode 214” para. 59 and Fig. 2) to a cathode and an anode, respectively, of an electrolysis unit (see Fig. 2), wherein:
the electrolysis unit is operated under an elevated gas pressure (“the SOEC may operate at a pressure between about 1 bar to about 20 bars” para. 36 and see Table 1), and
an oxygen-rich gas leaving the anode is subsequently expanded down to approximately ambient pressure using a gas expander (see below), the gas expander being downstream and not upstream of the electrolysis unit or units (Fig. 2 shows that “heat exchanger 233” i.e., the steam Rankine cycle (SRC) system, is disposed between the electrolysis unit and the exhaust).
Regarding the limitation “an oxygen-rich gas leaving the anode is subsequently expanded down to approximately ambient pressure using a gas expander”. Braun teaches the gas exiting the anode is enriched in oxygen (“oxygen exiting SOEC 210 at anode 214” Table 1). Braun further teaches this gas is passed through “heat exchanger 233”, which is an SRC system (“steam Rankine cycle systems may be utilized to capture some of the syngas sensible and/or latent heat and the LFG combustion gas sensible and/or latent heat to produce electricity (see heat exchangers 225 and 233 respectively)” para. 59 and Fig. 2), wherein the pressure of the oxygen-rich gas is reduced to 100 kPa or about 1 atm i.e., approximately ambient pressure (“exhaust gas exiting SRC 233” Table 1) from 110 kPa (“gas entering SRC 233” Table 1), thereby generating electricity (see Fig. 2). As evidenced by e.g., Rackley, the pressure of a gas stream entering an SRC is reduced by being passed through an expansion turbine to generate electricity (see “From B to C” on p. 36 and Fig. 3.3). Thus, Braun anticipates the limitation “an oxygen-rich gas leaving the anode is subsequently expanded down to approximately ambient pressure using a gas expander”.
Regarding claim 2, claim 2 has been interpreted as “the electrolysis unit or electrolysis units is/are”.
Braun further teaches the electrolysis unit is a solid oxide electrolysis cell (SOEC) stacks (“SOEC 210” Fig. 2 and para. 58).
Regarding claim 3, Braun further teaches the SOEC stacks operate in thermoneutral mode (see below).
As evidenced by e.g., the instant specification, “thermoneutral mode” refers to operation wherein the influent and effluent of the SOEC have the same temperature (p. 8 line 31 – p. 9 line 7). Braun teaches the influent and effluent from both the anode and cathode sides are each 800 °C (“Heated compressed stream … entering SOEC 210 at cathode 212”, “Syngas stream exiting SOEC 210 at cathode 212”, “heated air to SOEC 210 at anode 214”, and “Oxygen exiting SOEC 210 at anode 214” Table 1).
Thus, Braun teaches the SOEC stack(s) operate in thermoneutral mode.
Regarding claims 4, 5, and 6, Braun anticipates the limitations of claims 1 (claim 4), 2 (claim 5), and 3 (claim 6) as described above.
Braun further teaches the synthesis gas is methanol synthesis gas configured for production of methanol (“the syngas may be converted to liquid fuels including, but not limited to, diesel, jet, gasoline, and light fuel gas” para. 41 and see below).
As evidenced by Reytier, the same composition of syngas used to form diesel is used to produce methanol (“Methanol … 1/2” and “Diesel … 1/2” Table 1). Therefore, as Braun teaches the synthesis gas is suitable for forming diesel, the synthesis gas of Braun is suitable for forming methanol.
Regarding claim 12, Braun anticipates the limitations of claim 1, as described above.
Braun further teaches a compressor and the gas expander are connected to different lines (Fig. 2 shows “syngas compressor 228” is on the cathode line, while “heat exchanger 233” i.e., the gas expander, is on the anode line).
Regarding claim 13, Braun anticipates the limitations of claim 1, as described above.
Braun further teaches a compressor and the gas expander are connected to a mutual line (Fig. 2 shows “compressor 220” and “heat exchanger 233” i.e., the gas expander, are both disposed on the anode line).
Regarding claim 14, Braun anticipates the limitations of claim 1, as described above.
Braun further teaches the gas is further expanded down to a pressure of 100 kPa, or 0 barg, a value within the claimed range, by the gas expander (“exhaust gas exiting SRC 233” Table 1).
Regarding claim 15, Braun anticipates the limitations of claim 1, as described above.
Braun further teaches pre-heating the air in a feed/effluent heat exchanger to a first elevated temperature T1 (“Air exiting compressor 220 may be heated in … heat exchanger 216” para. 59 and Fig. 2, see also Table 1).
Regarding claim 18, Braun further teaches after oxygen-enriched air leaves the SOEC stacks, heat is recuperated in the feed/effluent heat exchanger (Fig. 2 and Table 1 show heat is transferred from the oxygen-enriched air leaving the anode to the air in heat exchanger 216), and wherein the oxygen-enriched air subsequently enters the gas expander (Fig. 2 shows “heat exchanger 233” i.e., the gas expander, is located downstream from “heat exchanger 216”).
Regarding claim 20, Braun teaches a method for generating synthesis gas containing hydrogen, carbon monoxide or mixtures of hydrogen, carbon monoxide and carbon dioxide by electrolysis (para. 3),
said method comprising feeding steam (“The polished feed stream may be combined with hydrogen and steam … The preheated polished feed stream may be fed into the SOEC 210 at the cathode 212” Fig. 2 and para. 58) and compressed air (“Air exiting compressor 220 may … be provided to the SOEC 210 at the anode 214” para. 59 and Fig. 2) to a cathode and an anode, respectively, of an electrolysis unit (see Fig. 2), wherein:
the electrolysis unit is operated under an elevated gas pressure (“the SOEC may operate at a pressure between about 1 bar to about 20 bars” para. 36 and see Table 1), and
an oxygen-rich gas leaving the anode is subsequently expanded down to approximately ambient pressure using a gas expander (see below), the gas expander being downstream and not upstream of the electrolysis unit or units (Fig. 2 shows that “heat exchanger 233” i.e., the steam Rankine cycle system, is disposed between the electrolysis unit and the exhaust),
wherein the compressed air is compressed to a pressure of up to 19 barg, a range within the claimed range (“the SOEC may operate at a pressure between about 1 bar to about 20 bars” para. 36), and
the oxygen-rich gas leaving the anode has a temperature of 800 °C, a value within the claimed range (“Oxygen exiting SOEC 210 at anode 214” Table 1).
Regarding the limitation “an oxygen-rich gas leaving the anode is subsequently expanded down to approximately ambient pressure using a gas expander”. Braun teaches the gas exiting the anode is enriched in oxygen (“oxygen exiting SOEC 210 at anode 214” Table 1). Braun further teaches this gas is passed through “heat exchanger 233”, which is an SRC system (“steam Rankine cycle systems may be utilized to capture some of the syngas sensible and/or latent heat and the LFG combustion gas sensible and/or latent heat to produce electricity (see heat exchangers 225 and 233 respectively)” para. 59 and Fig. 2), wherein the pressure of the oxygen-rich gas is reduced to 100 kPa or about 1 atm i.e., approximately ambient pressure (“exhaust gas exiting SRC 233” Table 1) from 110 kPa (“gas entering SRC 233” Table 1), thereby generating electricity (see Fig. 2). As evidenced by e.g., Rackley, the pressure of a gas stream entering an SRC is reduced by being passed through an expansion turbine to generate electricity (see “From B to C” on p. 36 and Fig. 3.3). Thus, Braun anticipates the limitation “an oxygen-rich gas leaving the anode is subsequently expanded down to approximately ambient pressure using a gas expander”.
Claim Rejections - 35 USC § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claims 7-9 and 19 are rejected under 35 U.S.C. 103 as being unpatentable over Braun (US Pat. Pub. 2014/0272734) as evidenced by, in the case of claim 7, Universal Industrial Gases (“Air: Its Composition and Properties” (2019) www.uigi.com/air.html#:~:text=Standard%20dry%20air%2C%20which%20is,recovered%20as%20industrial%20gas%20products).
Regarding claim 7, Braun anticipates the limitations of claim 2, as detailed in the rejection under 35 U.S.C. § 102(a)(1), above, incorporated herein by reference.
Braun does not explicitly teach the air is compressed in an amount sufficient to achieve 50% (v/v) oxygen at an exit of the SOEC stacks.
However, Braun teaches the air is compressed in an amount sufficient to achieve about 48% (v/v) oxygen at an exit of the SOEC stacks (see below), a value not materially different from the claimed value of 50% (v/v). A value very close to a claimed value establishes a prima facie case of obviousness (MPEP § 2144.05).
Braun teaches the air is compressed to a pressure of 180 kPa at 800 °C with a flow rate of 4.57 kg/s (see Table 1, annotated below), and the oxygen-enriched stream exits the electrolyzer at a pressure of 170 kPa at 800 °C with a flow rate of 7.21 kg/s (see Table 1, partially reproduced and annotated below).
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Annotated Partial Braun Table 1
As no air is consumed in the electrolyzer, the amount of oxygen in the oxygen-enriched stream is equal to the amount of the oxygen in the air plus the amount of oxygen produced by the electrolyzer. Dry air is 23.20% oxygen by mass, 75.47% nitrogen by mass, and 1.28% argon by mass as evidenced by Universal Industrial Gases (see Table 1, reproduced below). The oxygen-rich output stream of the electrolyzer in Braun thus comprises 3.7 kg/s of oxygen, 3.45 kg/s of nitrogen about 0.06 kg/s of Ar and negligible amounts of other gases (see calculations, below). Dividing the mass of each gas component by their respective molar masses provides the composition of the gas as a molar ratio. As evidenced by Universal Industrial Gases, the molar masses of oxygen, nitrogen, and argon are 32.00, 28.01 and 39.95 g/mol, respectively. The oxygen-rich output stream of Braun thus comprises 115 mol/s O2, 123 mol/s N2 and 1.5 mol/s Ar, or 48% oxygen (mol/mol). The volumetric composition of a gas is directly proportional to its molar composition as shown by the ideal gas law, PV = nRT.
Thus, in the method of Braun, the air is compressed in an amount sufficient to achieve 48% (v/v) oxygen at an exit of the SOEC stacks.
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Universal Industrial Gases Table 1
The masses of the gases in the oxygen-rich stream of Braun were calculated in the following manner. First, the relative masses of the gases in the feed stream were determined to be 1.06 kg/s oxygen, 3.45 kg/s nitrogen and 0.06 kg/s argon by multiplying the mass % the respective gases in air by the flow rate of the feed stream i.e., 4.57 kg/s. The amount of other gases in the feed stream was determined, in the same manner, to be less than 0.01 kg/s and were thus not included in the subsequent analysis. The amount of oxygen added to the stream by the electrolyzer was determined by subtracting the flow rate of the feed stream i.e., 4.57 kg/s, from the flow rate of the output stream i.e., 7.21 kg/s, giving 2.64 kg/s of oxygen added to the flow by the electrolyzer. The mass of nitrogen and argon in the stream is not changed by the electrolyzer, and thus the mass of nitrogen and argon in the oxygen-rich stream is the same as that in the feed stream i.e., 3.45 kg/s and 0.06 kg/s respectively. The mass of oxygen in the oxygen-rich stream is equal to the sum of the mass of oxygen present in the feed stream i.e., 1.06 kg/s, plus that added by the electrolyzer i.e., 2.64 kg/s.
Regarding claim 8, Braun anticipates the limitations of claim 2, as detailed in the rejection under 35 U.S.C. § 102(a)(1), above, incorporated herein by reference.
Braun further teaches the steam is mixed with hydrogen (“The polished feed stream may be combined with hydrogen and steam” para. 58 and “H2” Fig. 2) and pre-heated in a feed/effluent heat exchanger on a cathode side of the SOEC stacks (“which may have been previously processed in heat exchanger 224)” Id.).
Braun does not, in the embodiment depicted in Fig. 2, teach the hydrogen is recycled hydrogen.
However, Braun further teaches, in a second embodiment, that hydrogen produced by the SOEC stack may suitably be recycled into the steam fed to the cathode (“The polished carbon dioxide feed stream may then be mixed with steam stream 107 and/or hydrogen recycle gas stream 109 to produce an enriched feed stream.” Para. 57 and Fig. 1).
As Braun teaches a method of producing syngas in an SOEC, Braun is analogous art to the instant invention.
It would therefore have been obvious to a person having ordinary skill in the art before the effective filing date of the instant application to modify the method of Braun, such that at least a portion of the hydrogen supplied to the cathode is recycled hydrogen. A person having ordinary skill in the art would have been motivated to make this modification because Braun suggests using recycled hydrogen as at least a portion of the hydrogen added to the cathodic feed stream.
Regarding claim 9, Braun further teaches on the cathode side, steam is electrolyzed and oxygen ions are transported across an electrolyte to an anode side of the SOEC stacks (because the anode output is oxygen and the cathode input is steam, see Fig. 1, oxygen is necessarily transported across the electrolyte to the anode side of the SOEC stacks).
Regarding claim 19, Braun anticipates the limitations of claim 1, as detailed in the rejection under 35 U.S.C. § 102(a)(1), above, incorporated herein by reference.
Braun further teaches the compressed air is compressed to up to 19 barg (“a pressure between about 1 bar to about 20 bars” para. 33), a range close to the claimed range. A claimed range that does not overlap with, but is close to, a range disclosed in the prior art establishes a prima facie case of obviousness (MPEP § 2144.05(I)).
Claims 10, 16 and 17 are rejected under 35 U.S.C. 103 as being unpatentable over Braun in view of Rueger (US Pat. Pub. 2018/0287179).
Regarding claim 10, claim 10 has been interpreted as “wherein a second stream of hydrogen mixed with steam is passed through the feed/effluent heat exchanger prior to being further cooled down by generating high pressure steam”.
Braun renders the limitations of claim 8 obvious, as described above.
Braun further teaches a second stream of hydrogen mixed with steam i.e., the cathodic effluent (see Fig. 2), is passed through the feed/effluent heat exchanger (“The syngas enters a heat-exchanger 224 where steam is produced and may be provided to the polished feed stream.” para. 58 and Fig. 2, note the syngas is the effluent of the SOEC and comprises of a mixture of hydrogen and leftover steam).
Braun does not teach the second stream of hydrogen mixed with steam is subsequently further cooled down by generating high pressure steam.
Braun instead teaches the second stream is subsequently cooled down in an expansion turbine to generate electricity (“steam Rankine cycle systems may be utilized to capture some of the syngas sensible and/or latent heat … to produce electricity (see heat exchangers 225 …” para. 59 and Fig. 2).
However, Rueger teaches a method for recovering thermal energy in an SOEC (“electrolytic cell 5” Fig. 3 and abstract), wherein a cathodic effluent comprising hydrogen and steam (“hot hydrogen-steam mixture 4” Fig. 3 and para. 82) is passed through a feed/effluent heat exchanger (“recuperative preheater 3” para. 92 and Fig. 3), and is subsequently further cooled down by generating high pressure steam (“e hydrogen-steam mixture 17 cooled in the heat exchanger 3 is optionally further cooled in a heat exchanger 18.” para. 85 and “To reduce the external steam requirement 1, the heat exchangers 18 and 35 can be used, instead of providing heat for external users, to generating steam.” para. 115 and Fig. 3), which provides the predictable benefit of reducing the steam required by the SOEC (Id.).
As Rueger teaches a for recovering thermal energy in an electrolyzer configured to produce hydrogen, Rueger is analogous art to the instant invention.
It would therefore have been obvious to a person having ordinary skill in the art before the effective filing date of the instant application to modify the method of Braun, by adding a step of further cooling down the second stream of hydrogen mixed with steam by generating high pressure steam after the second stream of hydrogen mixed with steam is passed through the feed/effluent heat-exchanger, as taught by Rueger. A person having ordinary skill in the art would have been motivated to make this modification to achieve the predictable benefit of reducing the amount of steam required by the SOEC, as taught by Rueger. A person having ordinary skill in the art would have had a reasonable expectation of success making this modification, because Braun teaches the second stream of hydrogen mixed with steam retains sufficient sensible and/or latent heat to use generating electricity. Furthermore, simple substitution of one known element for another (i.e., a step of cooling down and generating steam as taught by Ruger rather than a step of cooling down and generating electricity as taught by Braun) to achieve predictable results (reducing the amount of steam required by the system/method) establishes a prima facie case of obviousness (MPEP § 2143(I)(B)).
Regarding claim 16, Braun anticipates the limitations of claim 15, as detailed in the rejection under 35 U.S.C. § 102(a)(1), above, incorporated herein by reference.
Modified Braun does not teach that, following pre-heating, the pre-heated air enters an electrical pre-heater which heats the air to a second elevated temperature T2, wherein T2>T1.
Braun instead teaches a step wherein following pre-heating, the pre-heated air enters a second heat exchanger which heats the air to a second elevated temperature T2, wherein T2>T1 (“Air exiting compressor 220 may be heated in heat-exchanger 218” para. 59 and Fig. 2, see also Table 1).
However, Rueger teaches a method for recovering thermal energy in an electrolyzer (“electrolytic cell 5” Fig. 3), wherein an air feed (“Purge air 9” Fig. 3) is pre-heated in a feed/effluent heat exchanger (“heat exchanger 11” Fig. 3) to a first elevated temperature T1 (see e.g., para. 137) and, following pre-heating, the pre-heated air enters an electrical pre-heater (“heater 13” and “electric energy 14” Fig. 3 and para. 83) which heats the air to a second elevated temperature T2, wherein T2>T1 (“In the heater 13, the further heating of the scavenging air with electric energy 14 takes place up to the electrolysis cell inlet temperature” Id.).
Both the second heat exchanger in the method of modified Braun and the electrical pre-heater in the method of Rueger serve the same, predictable purpose of heating the air to a second elevated temperature, wherein the second temperature (T2) is greater than the temperature of the air leaving the (first) feed/effluent heat exchanger (T1).
As Rueger teaches a for recovering thermal energy in an electrolyzer configured to produce hydrogen, Rueger is analogous art to the instant invention.
It would therefore have been obvious to a person having ordinary skill in the art before the effective filing date of the instant application to modify the method of Braun by using an electric pre-heater in place of the second heat exchanger, as taught by Rueger. A person having ordinary skill in the art would have been motivated to make this modification because Rueger teaches an electric pre-heater is a suitable means for further increasing the temperature of a pre-heated air stream supplied to the anode of an SOEC. Simple substitution of one known element for another to achieve predictable results establishes a prima facie case of obviousness (MPEP § 2143(I)(B)).
Regarding claim 17, Braun further teaches the second elevated temperature T2 is an inlet temperature of the SOEC stacks (Table 1, para. 59, and Fig. 2 show the air is supplied directly from “heat exchanger 218” to the anode side of the SOEC).
Claim 11 is rejected under 35 U.S.C. 103 as being unpatentable over Braun in view of Rueger, as applied to claim 10, and further in view of Boardman (WO 2008/154257 A2).
Regarding claim 11, modified Braun renders the limitations of claim 10 obvious, as described above.
Braun further teaches, in a second embodiment, splitting the second stream into a recycle hydrogen stream and a residual stream (“The heated dry syngas stream may then be split using a splitter 132 to produce a syngas side-stream and a main syngas stream” and “The hydrogen recycle stream 109 from the pressure swing adsorption (PSA) system 138 may be a recycle stream derived from the syngas produced by the SOEC 110” para. 57 and see Fig. 1).
It would therefore have been obvious to a person having ordinary skill in the art before the effective filing date of the instant application to modify the method of Braun, such that the second stream is split into a recycle hydrogen stream and a residual stream. A person having ordinary skill in the art would have been motivated to make this modification because it is suggested by Braun.
Modified Braun does not teach the residual stream is sent to ammonia synthesis. Modified Braun instead teaches the residual stream is sent to “gas-to-liquid conversion process 134 that produces the liquid fuels (e.g. Fisher-Tropsch process)” (para. 57).
However, Boardman teaches a process wherein a hydrogen stream generated from high-temperature steam electrolysis is combined with nitrogen to produce ammonia (“Hydrogen produced by the electrolysis of water may also be combined with nitrogen to produce ammonia.” abstract and see para. 33).
Both the residual stream of Braun and the hydrogen stream of Boardman serve the same, predictable, art-recognized purpose as a starting material for the synthesis of chemical products.
As Boardman teaches a method for generating hydrogen by electrolysis, Boardman is analogous art to the instant invention.
It would therefore have been obvious to a person having ordinary skill in the art before the effective filing date of the instant application to modify the method of Braun, such that the residual stream is sent to an ammonia synthesis process, as taught by Boardman, rather than the liquid fuel synthesis process of Braun. A person having ordinary skill in the art would have been motivated to make this modification to achieve the predicable benefit of synthesizing ammonia, as taught by Boardman. A person having ordinary skill in the art would have had a reasonable expectation of success for making this modification as both the residual streams of Braun and Boardman comprise hydrogen gas. Furthermore, simple substitution of a known step (the liquid fuel production process of Braun) for another known step (the ammonia production step of Boardman) to obtain predictable results establishes a prima facie case of obviousness (MPEP § 2143(I)(B)).
Claim 21 is rejected under 35 U.S.C. 103 as being unpatentable over Braun (US Pat. Pub. 2014/0272734) in view of Severinsky (US Pat. Pub. 2006/0211777 A1) and as evidenced by Rackley (“Carbon Capture and Storage - 3.1.5 Rankine Steam Cycle.” (2010) Elsevier).
Regarding claim 21, Braun teaches a method for generating synthesis gas containing hydrogen, carbon monoxide or mixtures of hydrogen, carbon monoxide and carbon dioxide by electrolysis (para. 3),
said method comprising feeding steam (“The polished feed stream may be combined with hydrogen and steam … The preheated polished feed stream may be fed into the SOEC 210 at the cathode 212” Fig. 2 and para. 58) and compressed air to a cathode and an anode, respectively (“Air exiting compressor 220 may … be provided to the SOEC 210 at the anode 214” para. 59 and Fig. 2), of an electrolysis unit (see Fig. 2), wherein:
the electrolysis unit is operated under an elevated gas pressure (“the SOEC may operate at a pressure between about 1 bar to about 20 bars” para. 36 and Table 1), and
an oxygen-rich gas leaving the anode is subsequently expanded down to approximately ambient pressure using a gas expander (see below), the gas expander being downstream and not upstream of the electrolysis unit or units (Fig. 2 shows that “heat exchanger 233” i.e., the steam Rankine cycle system, is disposed between the electrolysis unit and the exhaust).
Regarding the limitation “an oxygen-rich gas leaving the anode is subsequently expanded down to approximately ambient pressure using a gas expander”. Braun teaches the gas exiting the anode is enriched in oxygen (“oxygen exiting SOEC 210 at anode 214” Table 1). Braun further teaches this gas is passed through “heat exchanger 233”, which is an SRC system (“steam Rankine cycle systems may be utilized to capture some of the syngas sensible and/or latent heat and the LFG combustion gas sensible and/or latent heat to produce electricity (see heat exchangers 225 and 233 respectively)” para. 59 and Fig. 2), wherein the pressure of the oxygen-rich gas is reduced to 100 kPa or about 1 atm i.e., approximately ambient pressure (“exhaust gas exiting SRC 233” Table 1) from 110 kPa (“gas entering SRC 233” Table 1), thereby generating electricity (see Fig. 2). As evidenced by e.g., Rackley, the pressure of a gas stream entering an SRC is reduced by being passed through an expansion turbine to generate electricity (see “From B to C” on p. 36 and Fig. 3.3). Thus, Braun anticipates the limitation “an oxygen-rich gas leaving the anode is subsequently expanded down to approximately ambient pressure using a gas expander”.
Braun does not teach the electrolysis unit is a first electrolysis unit of a series of electrolysis units.
However, Severinsky teaches that using a series of electrolysis units rather than a single electrolysis unit provides the predictable benefits of improving safety and making installation and maintenance more convenient (para. 195).
As Braun teaches a method of producing syngas using an SOEC, Braun is analogous art to the instant invention. As Severinsky teaches a method of producing syngas using a steam electrolyzer (e.g., para. 87), Severinsky is analogous art to the instant invention.
It would therefore have been obvious to a person having ordinary skill in the art before the effective filing date of the instant application to modify the method of Braun, such that the electrolysis unit is a first electrolysis unit of a series of electrolysis units, as taught by Severinsky. A person having ordinary skill in the art would have been motivated to make this modification to achieve the predictable benefits of improved safety and more convenient installation and maintenance, as taught by Severinsky. Furthermore, combining prior art elements according to known methods to yield predictable results establishes a prima facie case of obviousness (MPEP § 2143(I)(A)). Furthermore, duplication of parts, absent evidence of unexpected results, establishes a prima facie case of obviousness (MPEP § 2144.04(VI)(B)).
Response to Arguments
Applicant’s arguments, see Remarks p. 7-8, filed 03/30/2026, with respect to the rejections of claims 4-6 under 35 U.S.C. § 112(b) have been fully considered, and are persuasive. The rejections of claim 4-6 under 35 U.S.C. § 112(b) have been withdrawn.
Applicant’s arguments, see Remarks p. 8-14, filed 03/30/2026, with respect to the rejections of claims 1-21 under 35 U.S.C. § 103 have been fully considered and are persuasive. Therefore, the rejection has been withdrawn. However, upon further consideration, a new ground(s) of rejection is made in view of Braun.
As each of Applicant’s arguments are directed to the combination of Braun with Adler, and Adler is no longer relied upon in the new ground(s) of rejection, Applicant’s arguments are considered moot.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to ALEXANDER R PARENT whose telephone number is (571)270-0948. The examiner can normally be reached M-F 11:00 AM - 6 PM EST.
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Luan V. Van can be reached on (571)272-8521. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
/ALEXANDER R. PARENT/Examiner, Art Unit 1795
/LUAN V VAN/Supervisory Patent Examiner, Art Unit 1795
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