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 .
Election/Restrictions
Applicant's election with traverse of Group I, claims 1-13 in the reply filed on 4/16/2026 is acknowledged. The traversal is on the ground(s) that claim 14, has been amended to depend from claim 1 to require the process of claim 1. This is not found persuasive because the special technical feature, the process of claim 1, fails to define a contribution over Duarte in view of Kopfle, as stated below, therefore, there is a lack of unity between the cited claims.
The requirement is still deemed proper and is therefore made FINAL.
Claim 14 is withdrawn from further consideration pursuant to 37 CFR 1.142(b), as being drawn to a nonelected invention, there being no allowable generic or linking claim. Applicant timely traversed the restriction (election) requirement in the reply filed on 4/16/2026.
Claim Objections
Claim 3 is objected to because of the following informalities:
Claim 3, line 3: amend “the shaft furnace” to “the further shaft furnace”
Appropriate correction is required.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 7 and 11 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 7 recites the limitations "the compressor means" and “the deducting device” in lines 5 and 6, respectively. There is insufficient antecedent basis for these limitations in the claim.
Claim 11 recites the limitation “etc.” with respect to the industrial plant. It is unclear what other types of devices could be included in the industrial plant to meet this limitation. Clarification is required.
Claim Interpretation
The following is a quotation of 35 U.S.C. 112(f):
(f) Element in Claim for a Combination. – An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof.
The following is a quotation of pre-AIA 35 U.S.C. 112, sixth paragraph:
An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof.
The claims in this application are given their broadest reasonable interpretation using the plain meaning of the claim language in light of the specification as it would be understood by one of ordinary skill in the art. The broadest reasonable interpretation of a claim element (also commonly referred to as a claim limitation) is limited by the description in the specification when 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, is invoked.
As explained in MPEP § 2181, subsection I, claim limitations that meet the following three-prong test will be interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph:
(A) the claim limitation uses the term “means” or “step” or a term used as a substitute for “means” that is a generic placeholder (also called a nonce term or a non-structural term having no specific structural meaning) for performing the claimed function;
(B) the term “means” or “step” or the generic placeholder is modified by functional language, typically, but not always linked by the transition word “for” (e.g., “means for”) or another linking word or phrase, such as “configured to” or “so that”; and
(C) the term “means” or “step” or the generic placeholder is not modified by sufficient structure, material, or acts for performing the claimed function.
Use of the word “means” (or “step”) in a claim with functional language creates a rebuttable presumption that the claim limitation is to be treated in accordance with 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph. The presumption that the claim limitation is interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, is rebutted when the claim limitation recites sufficient structure, material, or acts to entirely perform the recited function.
Absence of the word “means” (or “step”) in a claim creates a rebuttable presumption that the claim limitation is not to be treated in accordance with 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph. The presumption that the claim limitation is not interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, is rebutted when the claim limitation recites function without reciting sufficient structure, material or acts to entirely perform the recited function.
Claim limitations in this application that use the word “means” (or “step”) are being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, except as otherwise indicated in an Office action. Conversely, claim limitations in this application that do not use the word “means” (or “step”) are not being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, except as otherwise indicated in an Office action.
Claim 1 recites the limitation “heater-reformer means” followed by the functional language “to generate a syngas from natural gas.” However, the heater-reformer means is not modified by sufficient structure, material, or acts for performing the claimed function. Therefore, the “heater-reformer means” is being interpreted under 112(f) and is being given the broadest reasonable interpretation per the specification, which states “a MIDREX NG plant can be used in which a reformer is installed and where syngas, mainly CO and H2, is formed within by reforming natural gas.” See Specification, pg. 11, lines 20-30.
Claim 1 recites the limitation “electrolysis means” followed by the functional language “configured to produce hydrogen from steam.” However, the electrolysis means is not modified by sufficient structure, material, or acts for performing the claimed function. Therefore, the “electrolysis means” is being interpreted under 112(f) and is being given the broadest reasonable interpretation per the specification, which states “steam is supplied to a steam-fed electrolysis unit that can convert steam into hydrogen and oxygen by using electricity as input and any appropriate electrolysis unit can be used including a solid oxide electrolyzer cell.” See Specification, pg. 4, lines 1-4.
Claim 1 recites the limitation “gas shift reactor means” followed by the functional language “configured to convert CO-bearing gas into hydrogen and to remove CO2.” However, the gas shift reactor means is not modified by sufficient structure, material, or acts for performing the claimed function. Therefore, the “gas shift reactor means” is being interpreted under 112(f) and is being given the broadest reasonable interpretation per the specification, which states “equipment based on water gas shift technology, which describes the reaction of carbon monoxide and water vapor to form carbon dioxide and hydrogen.” See Specification, pg. 10, lines 4-7.
Claims 3, 4, 5, 6, 8, 9, and 10, recite the limitation “heat recovery means” followed by the functional language “to recover heat” from various sources, i.e., top gas, flue gas and hot DRI. However, the heat recovery means is not modified by sufficient structure, material, or acts for performing the claimed function. Therefore, the “heat recovery means” is being interpreted under 112(f) and is being given the broadest reasonable interpretation per the specification, which states “any heat recovery equipment can be used including a heat exchanger or a boiler.” See Specification, pg. 3, lines 27-31.
This application includes one or more claim limitations that use the word “means” or “step” but are nonetheless not being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph because the claim limitation(s) recite(s) sufficient structure, materials, or acts to entirely perform the recited function. Such claim limitations are: “the compressor means” in claims 7 and 12 and “gas cleaning means” in claim 12.
Because this/these claim limitations are not being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, they are not being interpreted to cover only the corresponding structure, material, or acts described in the specification as performing the claimed function, and equivalents thereof.
If applicant intends to have this/these limitation(s) interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, applicant may: (1) amend the claim limitation(s) to remove the structure, materials, or acts that performs the claimed function; or (2) present a sufficient showing that the claim limitation(s) does/do not recite sufficient structure, materials, or acts to perform the claimed function.
Specifically, the “compressor means” of claims 7 and 12 is not followed by functional language and the “gas cleaning means” of claim 12 is also not followed by functional language. Therefore these limitations fail the second prong of the test and are not being interpreted under 35 U.S.C. 112(f).
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.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1-13 are rejected under 35 U.S.C. 103 as being unpatentable over Duarte (WO 2020/245070 A1, hereinafter “Duarte”) in view of Kopfle and Griscom, “ ‘It All Started in Portland …’ 50 Years Ago,” MIDREX technical article June 2019 (hereinafter “Kopfle”).
Applicant provided a copy of Duarte with the IDS filed 12/2/2025.
Regarding claims 1, 2, 3, 4, 6, and 11, Duarte teaches a method for producing molten steel or molten-iron-containing materials with reduced emissions (Duarte, pg.2, paragraph 3). Duarte teaches the method comprises producing DRI in a direct reduction furnace with a reducing gas comprising hydrogen, melting at least a portion of the DRI in a melting furnace and generating hot gases, producing steam and/or hot water using the heat containing the hot gases, and producing hydrogen and/or hot water from the steam by electrolysis, where at least a portion of the hydrogen may be fed to the direct reduction furnace as a component of the reducing gas to produce DRI (Duarte, pg. 2, paragraph 3).
Duarte teaches Figure 2 which includes the direct reduction plant 12 comprising a direct reduction shaft furnace 50 from which DRI 18 is discharged, where the DRI are formed by the reaction of iron oxides with a reducing gas stream 6 mainly composed of hydrogen 16 (Duarte, pg. 4, paragraph 3 and Figure 2). Duarte teaches a stream of exhausted reducing gas is extracted from the reduction furnace 50 as top gas 58 and is passed through a heat exchanger 60 (Duarte, pg. 4, paragraph 4). The top gas 58, after exiting the heat exchanger 60 is cleaned and cooled down in a gas cooler 66 with water, then the water vapor contained in the top gas 58 is condensed in the cooler 55 as water stream 68 and can be fed to the electrolysis unit 34 (Duarte, pg. 5, paragraph 1). Duarte teaches a major portion 76 of the clean top gas 70 is recycled through a compressor 78 and the recycled gas stream 80, mainly composed of hydrogen, is then passed through a gas heater 85 to elevate the temperature prior to entering the shaft furnace 50 (Duarte, pg. 5, paragraph 2-3).
Duarte then teaches the DRI is discharged from the reduction furnace 50 and charged hot to a melting furnace 90, usually an electric arc furnace, and hot gases 24 that are produced during the charging, melting, and refining of DRI are collected and exit the EAF 90 through duct 94 to produce steam 108 in a heat exchanger 96 (Duarte, pg. 6, paragraph 4-5). Duarte further teaches the hot gases are used to produce hot water which is fed to the electrolysis unit 34, where the water collected in the electrolysis unit is used to produce hydrogen 16, which is fed through pipe 116 to be mixed with recycled gas stream 80 before entering the gas heater 85 (Duarte, pg. 6, paragraph 5-7).
Duarte teaches hydrocarbon gas 82 is also added to the recycled gas stream 80 (Duarte, pg. 5, paragraph 3). Duarte also teaches the hydrocarbon gas 82, such as natural gas, is transformed to hydrogen and carbon monoxide in a catalytic reformer to form a reducing gas stream and introduced into the shaft furnace (Duarte, pg. 5, paragraph 5). However, Duarte does not explicitly disclose wherein the industrial plant includes a natural gas DR plant operating on reformed natural gas to produce DRI from iron ore, said natural gas DR plant including a further shaft furnace and a further process gas loop, said further process gas loop including heater-reformer means to generate a syngas from natural gas, to be fed to the further shaft furnace as reducing gas, i.e., Duarte does not disclose a second shaft furnace that uses natural gas as the reducing gas.
With respect to the difference, Kopfle teaches Figure 7 which includes the MIDREX Plant comprised of a heat recovery system, a reformer and a shaft furnace (Kopfle, pg. 10, Figure 7). Kopfle further teaches the shaft furnace produces DRI and top gases, in which the top gases are scrubbed, compressed, sent to the heat recovery system to remove the heat, added to natural gas in the reformer to produce a reducing gas comprising carbon monoxide and hydrogen, and sent to the shaft furnace (Kopfle, pg. 3, paragraph 5 and pg. 10, Figure 7). Kopfle also teaches in the heat recovery system, a hot fan pulls flue gas from the reformer through the heat exchangers and releases the spent flue gas through the stack into the atmosphere while the heat exchangers preheat hot and cold combustion air/top gas fuel, hot and cold feed gas, and natural gas added to the reducing gas and shaft furnace (Kopfle, pg. 7, paragraph 2 to pg. 8, paragraph 1).
As Kopfle expressly teaches the use of the MIDREX system allows for the reduction of overall energy consumption and enhancement of environmental performance by using the heat recovery system (Kopfle, pg. 7, paragraph 2).
Duarte and Kopfle are analogous art as they are both directed to the formation of steel using a DRI intermediate product (Duarte, Abstract; Kopfle, pg. 4, paragraph 2).
In light of the motivation to use the MIDREX Plant as taught in Kopfle above, it therefore would have been obvious to one of ordinary skill in the art to include the MIDREX Plant in addition to the hydrogen system of Duarte in order to reduce the overall energy consumption and enhance the environmental performance by using the heat recovery system (Kopfle, pg. 7, paragraph 2), and thereby arrive at the present invention.
The method of Duarte in view of Kopfle corresponds to a method of producing direct reduced iron, DRI of claim 1. The formation of DRI using the shaft furnace and a mainly hydrogen reducing gas of Duarte corresponds to operating a hydrogen direct reduction, DR, plant, wherein iron ore is reduced in a shaft furnace in a hydrogen rich atmosphere of claim 1. The recycling of the top gas through the various steps of Duarte corresponds to the shaft furnace being connected with a process gas loop arranged to receive top gas from the shaft furnace, treat the top gas before heating it in a heater device, and returning to the furnace a reducing gas comprising at least 85 vol.% hydrogen of claim 1. Moreover, given that Duarte teaches the use of a mainly hydrogen reducing gas, it would have been obvious to one of ordinary skill in the art that the reducing gas would comprise at least 50 vol.% hydrogen, i.e., greater than 50%, which overlaps with the present amount.
As set forth in MPEP 2144.05, in the case where the claimed range “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 (Fe. Cir. 1990).
The addition of the hydrogen, produced in the electrolysis unit, to the recycling stream before entering the gas heater of Duarte corresponds to wherein a hydrogen stream is added to said process gas loop upstream of said heater device of claim 1. Moreover, the use of the electrolysis unit to convert the hot gases and hot water from the EAF of Duarte corresponds to wherein at least part of said hydrogen stream is produced by at least one of: electrolysis means configured to produce hydrogen from steam recovered from one or more components of the industrial plant and/or from steam generated using waste heat and/or hot gases emitted by the one or more components; and gas shift reactor means configured to convert CO-bearing gas emitted by at least one component of the industrial plant into hydrogen and to remove CO2 of claim 1.
The steelmaking plant, including an EAF that produces hot gases of Duarte corresponds to operating an industrial plant generating CO-bearing gas and/or waste heat and/or hot gases of claim 1. The MIDREX NG Plant of Duarte in view of Kopfle corresponds to wherein the industrial plant includes a natural gas DR plant operating on reformed natural gas to produce DRI from iron ore, said natural gas DR plant including a further shaft furnace and a further process gas loop, said further process gas loop including heater-reformer means to generate a syngas from natural gas, to be fed to the further shaft furnace as reducing gas of claim 1.
The MIDREX NG Plant including the heat recovery system of Kopfle also corresponds to the following claims:
Claim 2, including recovering heat from the natural gas DR plant to generate steam and produce hydrogen in said electrolysis means
Claim 3, wherein heat recovery means are arranged on said further process gas loop of said natural gas DR plant, to be contacted with top gas after exit from the shaft furnace, to recover heat from recycled top gas and generate steam that is fed to said electrolysis means
Claim 4, wherein heat recovery means are arranged to recover heat from flue gas from the heater reformer means of said process gas loop of said natural gas DR plant, before a stack of said natural gas DR plant, to generate steam
Moreover, it would have been obvious to one of ordinary skill in the art to fed the steam produced in the heat recovery system to the electrolysis unit of Duarte in order to utilize heat energy produced in steelmaking processes and decreasing the use of hydrocarbons and CO2 emissions to the atmosphere (Duarte, pg. 2, paragraph 2), and thereby arrive at the present invention.
The use of an electric arc furnace and heat recovery unit in Duarte corresponds to:
Claim 6, wherein the industrial plant includes an EAF and heat recovery means are arranged to recover heat from waste heat and/or hot gasses emitted by said EAF to generate steam
Claim 11, wherein the industrial plant comprises one or more of a sinter plant, a coke oven plant, an Electric Arc Furnace, a Blast Furnace, a Submerged arc furnace (SAF), continuous casters, rolling mills, Basic Oxygen Furnace, etc.
Regarding claims 5 and 10, while Duarte and Kopfle do not explicitly disclose that the heat recovery means are arranged to recover heat from hot DRI produced by the hydrogen DR plant and natural gas DR plant, it would have been obvious to one of ordinary skill in the art that heat could be recovered from hot DRI prior to storing DRI for transportation and/or storage as hot DRI cannot be stored before cooling and the aim of both processes is to utilize heat energy produced (Duarte, pg. 2, paragraph 2; Kopfle, pg. 7, paragraph 2).
Regarding claim 7, the claim further limits the hydrogen stream is produced by gas shift reactor means, which is an optional embodiment of claim 1 (i.e., the hydrogen stream is produced by electrolysis means or gas shift reactor means) and therefore not required. As such claim 7 is rejected based on similar reasons as claim 1.
Regarding claims 8 and 9, Duarte further teaches the top gas 58 exits the direct reduction furnace 50 and is passed through a heat exchanger 60 where a suitable fluid 62 is heated, to produce steam 64, which can be utilized to produce hydrogen in the electrolysis unit 34 (Duarte, pg. 4, paragraph 4). The heat exchanger in the gas loop of Duarte corresponds to comprising recovering heat by means of heat recovery means arranged at one or more locations in the hydrogen DR plant, and feeding the generated steam to the electrolysis means of claim 8. Passing the steam to the electrolysis unit of Duarte corresponds to wherein heat recovery means are arranged on said further process gas loop of said hydrogen DR plant to be contacted with top gas after exit from said further shaft furnace, to recover heat from recycled top gas and generate steam fed to said electrolysis means of claim 9.
Regarding claim 12, Duarte teaches the top gas 58, after exiting the heat exchanger 60 is cleaned and cooled down in a gas cooler 66 with water, then the water vapor contained in the top gas 58 is condensed in the cooler 55 as water stream 68 and can be fed to the electrolysis unit 34 (Duarte, pg. 5, paragraph 1). Duarte also teaches in Figure 2, a compressor 78 upstream of the hydrogen stream 116 addition, which is upstream of the gas heater 85 (Duarte, Figure 2). The top gas process of Duarte corresponds to wherein said process gas loop includes gas cleaning means and compressor means upstream of said heater device, said hydrogen stream addition being done between said compressor means and heater device of claim 12.
Regarding claim 13, Duarte teaches the electrolysis unit 34 produces hydrogen 16, which is fed through pipe 116 to mix with the recycled gas stream 80 (Duarte, pg. 6, paragraph 7). Given that Duarte does not disclose any other gases in hydrogen 16, one of ordinary skill in the art would understand that the hydrogen 16 is about 100 vol.% hydrogen, which falls within wherein said hydrogen stream added to said process gas loop of said hydrogen DR plant contains 90 to 100 vol.% H2 of claim 13.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to DANIELLE CARDA whose telephone number is (571)270-1240. The examiner can normally be reached Monday-Friday 8:30-4:00 EST.
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/DANIELLE M. CARDA/Primary Examiner, Art Unit 1738
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