DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Response to Amendment
The Amendment filed 16 March 2026 has been entered. Claims 1, 4, 10-11, 13, and 17-18 are amended; claim 9 is cancelled. Accordingly, claims 1-8, and 10-20 remain pending in the application. Applicant’s amendments to the claims have overcome each and every 112(b) rejection previously set forth in the Non-Final Office Action mailed 16 December 2025.
Claim Objections
Claim 12 is objected to because of the following informalities:
Claim 12, line 1, "further reacting" should read "further comprising: reacting".
Appropriate correction is required.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claims 1-2, 5-6, and 8 are rejected under 35 U.S.C. 103 as being unpatentable over Kindig (US 2002/0127178) in view of Schora (US 3,442,619).
Regarding Claim 1, Kindig ‘178 discloses a method of producing hydrogen gas, the method comprising: reacting steam (steam meets the limitation of water) with a metal (metal meets the limitation of a metal in a reduced state) to form hydrogen and a metal oxide in a second reaction zone; and reacting a reducing gas with the metal oxide in a first reaction zone [0014] to form a metal and carbon dioxide [0032]. Kindig ‘178 further discloses the reducing gas includes carbon monoxide and is generated in a reduction gas reactor (104) by supplying carbon and oxygen [0026], such that CO production occurs in a first reactor. Kindig ‘178 further discloses the source of carbon can be coal, oil, biomass, or similar carbonaceous fuels [0027]. Kindig ‘178 further discloses the valve connecting the reactors and the gas generation zones is switched after a period of time such that the reducing gas is contacted with the metal oxide that was formed in the second reaction zone and steam is contacted with the metal that was formed in the first reaction zone to form hydrogen gas ([0014], Fig. 1, Fig. 2), such that both the second and third reactions occur in a second reactor (See Fig. 1 and Fig. 2). Kindig '178 further discloses steam methane reformation is one of the most common methods for producing hydrogen gas [0004], and steam methane reformation is believed to be the most economical and commercially viable process that is presently available (steam methane reformation is a reaction of methane and steam to produce hydrogen and carbon monoxide; [0005]).
Kindig ‘178 is silent to passing methane and water to the reduction gas reactor (104), such that methane and water react to form at least carbon monoxide and hydrogen.
Schora discloses a method for producing hydrogen gas, the method comprising: reacting steam with reduced iron to form hydrogen and oxidized iron (Col. 2, lines 33-42). Schora further discloses reacting the oxidized iron with a reducing gas to form reduced iron (Col. 2, lines 49-52), wherein the reducing gas used in the reduction reaction contains carbon monoxide and hydrogen (Col. 2, lines 62-63), and the reducing gas can be obtained from the least expensive and/or most convenient source such as the partial oxidation of methane with steam and air (obtaining reducing gas containing hydrogen and carbon monoxide by partial oxidation of methane with steam meets the limitation of reacting methane with water to form carbon monoxide and hydrogen; Col. 2, line 68-Col. 3, line 1). Schora further discloses a suitable tail gas from other plant operations can be used as the reducing gas (Col. 3, lines 6-7), such that Schora meets the limitation wherein the first reaction is in a first reactor. Schora further discloses reacting the oxidized iron with the carbon monoxide in the reducing gas also forms carbon dioxide (Col. 3, lines 36, 38).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Kindig ‘178 to incorporate the teachings of Schora to react methane and water to form at least carbon monoxide and hydrogen in the reduction gas reactor, because reducing gas obtained from the partial oxidation of methane with steam and air is the least expensive and/or most convenient source of reducing gas, as recognized by Schora (Col. 2, line 68-Col. 3, line 1), and Kindig ‘178 recognizes steam methane reformation is one of the most common methods for producing hydrogen gas [0004], and steam methane reformation is believed to be the most economical and commercially viable process that is presently available [0005].
Regarding Claim 2, Kindig ‘178 discloses the valve connecting the reactors and the gas generation zones is switched after a period of time such that the reducing gas is contacted with the metal oxide that was formed in the second reaction zone and steam is contacted with the metal that was formed in the first reaction zone to form hydrogen gas ([0014], Fig. 1, Fig. 2), such that the second and third reactions are sequentially alternated such that the reducing of the metal in the oxidized state in the third reaction forms the metal in a reduced state utilized in the second reaction (See Fig. 1 and Fig. 2).
Regarding Claim 5, Kindig ‘178 discloses the use of iron oxide [0029].
Regarding Claim 6, Kindig ‘178 discloses the use of iron oxide [0029].
Regarding Claim 8, Kindig ‘178 discloses the metal in a reduced state is Fe (aka Fe0) [0029].
Claim 3 is rejected under 35 U.S.C. 103 as being unpatentable over Kindig (US 2002/0127178) in view of Schora (US 3,442,619) and Kindig (US 2007/0256361).
Regarding Claim 3, Kindig ‘178 and Schora teach the elements as described above with regards to claim 1.
Kindig ‘178 discloses excess CO is preferably removed from the system and can be used as process heat, maximizing the use of unreacted CO [0031].
Kindig ‘178 is silent to reacting water with carbon monoxide to form at least carbon dioxide and hydrogen.
Kindig '361 discloses a method for producing hydrogen (H2) gas, the method comprising: reacting a hydrocarbon with O2 to form carbon monoxide (CO) and hydrogen [0075]. Kindig '361 further discloses in order to increase the amount of H2 derived from conventional gasification, some of the CO must be used to reduce H2O and form CO2 as a by-product via the water gas shift reaction, which is conducted in a separate reactor after gasification: CO+H2O → H2+CO2 ([0010], [0036]).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Kindig ‘178 to incorporate the teachings of Kindig ‘361 to react water carbon monoxide in the first reactor to form at least carbon dioxide and hydrogen in order to increase the amount of H2 produced, as recognized by Kindig ‘361 [0010].
Claim 4 is rejected under 35 U.S.C. 103 as being unpatentable over Kindig (US 2002/0127178) in view of Schora (US 3,442,619) and Michels (EP 3194331).
Regarding Claim 4, Kindig ‘178 and Schora teach the elements as described above with regards to claim 1.
Kindig ‘178 is silent to reacting carbon dioxide and water with the metal in a reduced state produced in the third reaction to form at least hydrogen and a metal carbonate; and reacting the metal carbonate with water to from a metal in an oxidized state, carbon dioxide, and hydrogen.
Michiels discloses a method for producing hydrogen gas (Abstract). Michiels further discloses reacting carbon dioxide and water with Fe0 (Fe0 meets the limitation of a metal in a reduced state) to form hydrogen and a FeCO3 (FeCO3 meets the limitation of a metal carbonate); and in another reaction, reacting the FeCO3 with water to form Fe3O4 (Fe3O4 meets the limitation of a metal in an oxidized state), carbon dioxide, and hydrogen [0032]. Michels further discloses by using a hydrothermal process in the presence of carbonate ions, it is possible to produce hydrogen with high purities and yield, under surprisingly mild conditions [0008].
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Kindig ‘178 to incorporate the teachings of Michels to react carbon dioxide and water with the metal in a reduced state to form at least hydrogen and a metal carbonate; and react the metal carbonate with water to from the metal in an oxidized state, carbon dioxide, and hydrogen in order to produce hydrogen with high purities and yield, under surprisingly mild conditions, as recognized by Michels [0008].
Claim 7 is rejected under 35 U.S.C. 103 as being unpatentable over Kindig (US 2002/0127178) in view of Schora (US 3,442,619) and Kim (US 2016/0296916).
Regarding Claim 7, Kindig ‘178 and Schora teach the elements as described above with regards to claim 1.
Kindig ‘178 discloses at least one of the metal oxides is FeO [0029].
Kindig ‘178 is silent to the metal in an oxidized state comprising Fe3O4.
Kim discloses when Fe metal is exposed to the oxidizing atmosphere, it may have various oxidation states, and is easily oxidized to iron oxide such as FeO, Fe3O4, and Fe2O3 [0022].
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Kindig ‘178 to incorporate the teachings of Kim wherein the metal in an oxidized state comprises Fe3O4, as the iron oxides of Kindig are not particularly limited, and the iron metal can be easily oxidized to both FeO as Fe3O4, as recognized by Kim [0022].
Claims 10-11 and 16-20 are rejected under 35 U.S.C. 103 as being unpatentable over Kindig (US 2002/0127178) in view of Schora (US 3,442,619).
Regarding Claim 10, Kindig ‘178 discloses a method of producing hydrogen gas, the method comprising: passing carbon and oxygen to a reduction gas reactor (104) (reduction gas reactor (104) meets the limitation of a first reactor), such that the carbon and oxygen react to form a reducing gas comprising carbon monoxide [0026], wherein the source of the carbon 106 can be, for example, coal, oil, biomass or similar carbonaceous materials [0027]; passing steam to a first reactor (110) (first reactor (110) meets the limitation of a second reactor) comprising iron, such that the steam reacts with the iron to form hydrogen and iron oxide (Fig. 1; [0029]); and passing the reducing gas comprising carbon monoxide produced in the reduction gas reactor (104) to the first reactor (110) while the iron oxide is positioned in the first reactor (110), such that the iron oxide reacts with the carbon monoxide to form the iron and carbon dioxide (Fig. 2). Kindig '178 further discloses steam methane reformation is one of the most common methods for producing hydrogen gas [0004], and steam methane reformation is believed to be the most economical and commercially viable process that is presently available (steam methane reformation is a reaction of methane and steam to produce hydrogen and carbon monoxide; [0005]).
Kindig ‘178 is silent to passing methane and water to the reduction gas reactor (104), such that methane and water react to form at least carbon monoxide and hydrogen.
Schora discloses a method for producing hydrogen gas, the method comprising: reacting steam with reduced iron to form hydrogen and oxidized iron (Col. 2, lines 33-42). Schora further discloses reacting the oxidized iron with a reducing gas to form reduced iron (Col. 2, lines 49-52), wherein the reducing gas used in the reduction reaction contains carbon monoxide and hydrogen (Col. 2, lines 62-63), and the reducing gas can be obtained from the least expensive and/or most convenient source such as the partial oxidation of methane with steam and air (obtaining reducing gas containing hydrogen and carbon monoxide by partial oxidation of methane with steam meets the limitation of reacting methane with water to form carbon monoxide and hydrogen; Col. 2, line 68-Col. 3, line 1). Schora further discloses a suitable tail gas from other plant operations can be used as the reducing gas (Col. 3, lines 6-7), such that Schora meets the limitation wherein the first reaction is in a first reactor. Schora further discloses reacting the oxidized iron with the carbon monoxide in the reducing gas also forms carbon dioxide (Col. 3, lines 36, 38).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Kindig ‘178 to incorporate the teachings of Schora to pass methane and water to the reduction gas reactor (104) (the first reactor of the present claim), such that methane and water react to form at least carbon monoxide and hydrogen, because reducing gas obtained from the partial oxidation of methane with steam and air is the least expensive and/or most convenient source of reducing gas, as recognized by Schora (Col. 2, line 68-Col. 3, line 1), and Kindig ‘178 recognizes steam methane reformation is one of the most common methods for producing hydrogen gas [0004], and steam methane reformation is believed to be the most economical and commercially viable process that is presently available [0005].
Regarding Claim 11, Kindig ‘178 further discloses the valve connecting the reactors and the gas generation zones is switched after a period of time such that the reducing gas is contacted with the metal oxide that was formed in the second reaction zone and steam is contacted with the metal that was formed in the first reaction zone to form hydrogen gas ([0014], Fig. 1, Fig. 2), such that the passing of the water to the second reactor and the passing of at least a portion of the carbon monoxide produced in the first reactor to the second reactor are sequentially alternated, such that the metal in a reduced state formed from the reaction of the metal in an oxidized state with the carbon dioxide forms the metal in a reduced state that is reacted with the water. (See Fig. 1 and Fig. 2).
Regarding Claim 16, Kindig ‘178 illustrates directly passing the carbon monoxide produced in the reduction gas reactor (104) to the first reactor (110) (Fig. 2).
Regarding Claim 17, Kindig ‘178 illustrates passing steam to a second reactor (112) (second reactor (112) meets the limitation of a third reactor) comprising iron, such that the steam reactor with the iron to form hydrogen and iron oxide in the second reactor (112) (Fig. 2); and passing carbon monoxide produced in the reduction gas reactor (104) to the second reactor (112) while iron oxide is positioned in the second reactor (112), such that the iron oxide reacts with the carbon monoxide to form iron and carbon dioxide (Fig. 1).
Regarding Claim 18, Kindig ‘178 illustrates the first reactor (110) is oxidizing the iron while the second reactor (112) is reducing the iron oxide (Fig.1); and the first reactor (110) is reducing the iron oxide while the second reactor (112) is oxidizing the iron (Fig. 2).
Regarding Claim 19, Kindig ‘178 discloses the use of iron oxide [0029].
Regarding Claim 20, Kindig ‘178 discloses the use of iron oxide [0029].
Claim 12 is rejected under 35 U.S.C. 103 as being unpatentable over Kindig (US 2002/0127178) in view of Schora (US 3,442,619) and Kindig (US 2007/0256361).
Regarding Claim 12, Kindig ‘178 and Schora teach the elements as described above with regards to claim 10.
Kindig ‘178 discloses excess CO is preferably removed from the system and can be used as process heat, maximizing the use of unreacted CO [0031].
Kindig ‘178 is silent to reacting water with carbon monoxide to form at least carbon dioxide and hydrogen.
Kindig '361 discloses a method for producing hydrogen (H2) gas, the method comprising: reacting a hydrocarbon with O2 to form carbon monoxide (CO) and hydrogen [0075]. Kindig '361 further discloses in order to increase the amount of H2 derived from conventional gasification, some of the CO must be used to reduce H2O and form CO2 as a by-product via the water gas shift reaction, which is conducted in a separate reactor after gasification: CO+H2O → H2+CO2 ([0010], [0036]).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Kindig ‘178 to incorporate the teachings of Kindig ‘361 to react water carbon monoxide in the first reactor to form at least carbon dioxide and hydrogen in order to increase the amount of H2 produced, as recognized by Kindig ‘361 [0010].
Claim 13 is rejected under 35 U.S.C. 103 as being unpatentable over Kindig (US 2002/0127178) in view of Schora (US 3,442,619) and Michels (EP 3194331).
Regarding Claim 13, Kindig ‘178 and Schora teach the elements as described above with regards to claim 10.
Kindig ‘178 discloses recycling carbon dioxide is recycled back to the reducing gas reactor (104) [0033].
Kindig ‘178 is silent to passing carbon dioxide to the second reactor comprising the metal in a reduced state such that the metal in a reduced state reacts with carbon dioxide and water to form at least hydrogen and a metal carbonate; and passing water to the second reactor comprising the metal carbonate and hydrogen such that the metal carbonate reacts with the water to form the metal in an oxidized state and carbon dioxide.
Michiels discloses a method for producing hydrogen gas (Abstract). Michiels further discloses reacting carbon dioxide and water with Fe0 (Fe0 meets the limitation of a metal in a reduced state) to form hydrogen and a FeCO3 (FeCO3 meets the limitation of a metal carbonate); and in another reaction, reacting the FeCO3 with water to form Fe3O4 (Fe3O4 meets the limitation of a metal in an oxidized state), carbon dioxide, and hydrogen [0032]. Michels further discloses by using a hydrothermal process in the presence of carbonate ions, it is possible to produce hydrogen with high purities and yield, under surprisingly mild conditions [0008].
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Kindig ‘178 to incorporate the teachings of Michels to pass carbon dioxide to the second reactor comprising the metal in a reduced state such that the metal in a reduced state reacts with carbon dioxide and water to form at least hydrogen and a metal carbonate; and pass water to the second reactor comprising the metal carbonate and hydrogen such that the metal carbonate reacts with the water to form the metal in an oxidized state and carbon dioxide in order to produce hydrogen with high purities and yield, under surprisingly mild conditions, as recognized by Michels [0008].
Claim 14 is rejected under 35 U.S.C. 103 as being unpatentable over Kindig (US 2002/0127178) in view of Schora (US 3,442,619) and Michels (EP 3194331) and Niitsuma (US 2010/0129284).
Regarding Claim 14, Kindig ‘178, Schora, and Michels teach the elements as described above with regards to claim 13.
Kindig ‘178 is silent to passing the carbon dioxide produced in the second reactor and hydrogen produced in the second reactor to a second separation unit; separating the carbon dioxide from the hydrogen in the second separation unit; passing the carbon dioxide separated in the second separation unit to a carbon dioxide storage vessel; and passing the carbon dioxide from the carbon dioxide storage vessel to the second reactor.
Niitsuma discloses a method for producing hydrogen from a carbon-containing fuel [0021], wherein the carbon-containing fuel may be methane [0084]. Niitsuma further discloses separation hydrogen and carbon dioxide using PSA ([0023], [0028]). Niitsuma further discloses CO2 may be stored and used as raw material for synthesis of chemical products [0113].
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Kindig ‘178 to incorporate the teachings of Niitsuma to pass the carbon dioxide produced in the second reactor and hydrogen produced in the second reactor to a second separation unit; separate the carbon dioxide from the hydrogen in the second separation unit; pass the carbon dioxide separated in the second separation unit to a carbon dioxide storage vessel; and pass the carbon dioxide from the carbon dioxide storage vessel to the second reactor, because separating carbon dioxide and hydrogen as well as storing and recycling carbon dioxide are process parameters well-known in the art of producing hydrogen, as recognized by Niitsuma.
Claim 15 is rejected under 35 U.S.C. 103 as being unpatentable over Kindig (US 2002/0127178) in view of Schora (US 3,442,619) and Murdoch (US 5,128,003).
Regarding Claim 15, Kindig ‘178 and Schora teach the elements as described above with regards to claim 10.
Kindig ‘178 is silent to passing at least some of the carbon monoxide produced in the first reactor and the hydrogen produced in the first reactor to a first separation unit; separating the carbon monoxide from the hydrogen in the first separation unit; passing the carbon monoxide separated in the first separation unit to a carbon monoxide storage vessel; and passing the carbon monoxide from the carbon monoxide storage vessel to the second reactor.
Murdoch discloses a method from producing hydrogen and carbon monoxide from methane and water (Abstract). Murdoch further discloses the hydrogen and carbon monoxide are directed to a hydrogen separator to separate the hydrogen from the carbon monoxide (Col. 4, lines 41-43). Murdoch further discloses carbon monoxide is stored for use (Col. 4, lines 67-68; Abstract).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Kindig ‘178 to incorporate the teachings of Murdoch to pass at least some of the carbon monoxide produced in the first reactor and the hydrogen produced in the first reactor to a first separation unit; separate the carbon monoxide from the hydrogen in the first separation unit; pass the carbon monoxide separated in the first separation unit to a carbon monoxide storage vessel; and pass the carbon monoxide from the carbon monoxide storage vessel to the second reactor, because separating carbon monoxide and hydrogen as well as storing and recycling carbon monoxide are process parameters well known in the art of producing hydrogen, as recognized by Murdoch.
Response to Arguments
Applicant’s arguments, see "Remarks", pg. 9, par. 2-pg. 10, par. 2, filed 16 March 2026, with respect to the rejection(s) of claim(s) 1-9 under 35 U.S.C. 102 and 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 Kindig '178 (US 2002/0127178) and Schora (US 3,442,619).
Applicant's arguments filed 16 March 2026 have been fully considered but they are not persuasive.
Applicant argues no prima facie case of obviousness has been presented because the modification of Kindig '178 to incorporate the teachings of Schora would impermissibly change the principle operation of Kindig '178, which is to continuously produce hydrogen through methods using a two-reactor system, wherein reducing gas is produced by using carbon dioxide that is recycled from one of the two reactors. This carbon dioxide recycle is essential to the continuous production of hydrogen in Kindig '178 because it allows the system to continuously produce reducing gas to be used to reduce iron oxide to form iron, which may then be reacted with steam to ultimately produce hydrogen. If Kindig '178 was modified to incorporate the teachings of Schora to pass methane and water to the gas reactor 104, the carbon dioxide recycle system would become redundant.
However, Kindig ‘178 discloses the carbon dioxide can be recycled back to the reactor for production of additional reducing gas [0033], such that recycling CO2 is not required and therefore is not a principle operation of Kindig ‘178. The reducing gas of Kindig is produced by carbon and oxygen [0026], wherein the carbon source can be coal, oil, biomass, or similar carbonaceous material [0027], such that the carbon source of Kindig is not particularly limited to carbon dioxide, and reacting methane and water to produce the carbon monoxide and hydrogen does not change the principle operation of Kindig to continuously produce hydrogen through methods using a two-reactor system.
Conclusion
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/S.E.S./Examiner, Art Unit 1735
/PAUL A WARTALOWICZ/Primary Examiner, Art Unit 1735
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