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 without traverse of Group I, Claims 1-3, 5-8, and 10-16 in the reply filed on 07/10/2026 is acknowledged.
Claims 17-22 and 24-25 are withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected invention, there being no allowable generic or linking claim. Election was made without traverse in the reply filed on 07/10/2026.
Status of Claims
Claims 4, 9, and 23 are canceled. Claims 17-22 and 24-25 are withdrawn due to a restriction requirement (see Election/Restrictions section above).
Claims 1-3, 5-8, and 10-16 are pending and are presented for examination on the merits.
Priority
Copies of the certified copies of the priority documents have been received in this National Stage application from the International Bureau.
Information Disclosure Statement
Two (2) information disclosure statements (IDS) were submitted on 02/27/2024 and 06/29/2026. The submissions are in compliance with the provisions of 37 CFR 1.97. Accordingly, the IDS are being considered by the examiner.
Drawings
The drawings are objected to as failing to comply with 37 CFR 1.84(p)(4) because reference characters "22" and "42" have both been used to designate a “reformer device” (page 10, lines 19-20 for “22” and page 15, line 19 for “42”).
The drawings are objected to as failing to comply with 37 CFR 1.84(p)(5) because they do not include the following reference sign(s) mentioned in the description: O2 is Figs. 1 and 2 and D3.1 in Fig. 2 are not described in the instant specification. The Examiner notes that O2 might be intended to be oxygen “O2” rather than a reference character “O2”, but it is unclear since “O1” is used as a reference character nearby in both Figs. 1 and 2.
The drawings are objected to as failing to comply with 37 CFR 1.84(p)(4) because the following reference characters designate more than one part:
reference character “22” has been used to designate “reformer device” (page 10, lines 19-20); “reformer or a heater” (page 11, lines 9-13); “reformer/heater” (page 13, line 5) and it is unclear whether “22” has to be a reformer, a heater, or a combination,
reference character “S2” has been used to designate “syngas” (page 15, line 21) and “heat exchanger” (page 14, line 6; the Examiner notes that “heat exchanger S2” of page 14 might possibly be intended to refer to “heat-exchanger 32” of page 14, line 3, but clarification is requested),
reference character “30” has been used to designate “enriching equipment” (page 13, line 29), “reforming equipment” (page 13, line 32), “dry reforming equipment” (page 14, lines 3-4), “equipment” (page 14, line 9), and “reformer stage” (page 15, line 15) and it is unclear what type of equipment “30” has to be, and
reference character “20” has been used to designate “vertical shaft furnace” (page 10, lines 4-5) and “direct reduction furnace” (page 13, line 28) and it is unclear whether “20” has to be a vertical shaft furnace or any type of direct reduction furnace.
Corrected drawing sheets in compliance with 37 CFR 1.121(d) are required in reply to the Office action to avoid abandonment of the application. Any amended replacement drawing sheet should include all of the figures appearing on the immediate prior version of the sheet, even if only one figure is being amended. Each drawing sheet submitted after the filing date of an application must be labeled in the top margin as either “Replacement Sheet” or “New Sheet” pursuant to 37 CFR 1.121(d). If the changes are not accepted by the examiner, the applicant will be notified and informed of any required corrective action in the next Office action. The objection to the drawings will not be held in abeyance.
Specification
The disclosure is objected to because of the following informalities: the instant abstract is 169 words long, which exceeds the maximum length of 150 words.
Applicant is reminded of the proper content of an abstract of the disclosure.
A patent abstract is a concise statement of the technical disclosure of the patent and should include that which is new in the art to which the invention pertains. The abstract should not refer to purported merits or speculative applications of the invention and should not compare the invention with the prior art.
If the patent is of a basic nature, the entire technical disclosure may be new in the art, and the abstract should be directed to the entire disclosure. If the patent is in the nature of an improvement in an old apparatus, process, product, or composition, the abstract should include the technical disclosure of the improvement. The abstract should also mention by way of example any preferred modifications or alternatives.
Where applicable, the abstract should include the following: (1) if a machine or apparatus, its organization and operation; (2) if an article, its method of making; (3) if a chemical compound, its identity and use; (4) if a mixture, its ingredients; (5) if a process, the steps.
Extensive mechanical and design details of an apparatus should not be included in the abstract. The abstract should be in narrative form and generally limited to a single paragraph within the range of 50 to 150 words in length.
See MPEP § 608.01(b) for guidelines for the preparation of patent abstracts.
Appropriate correction is required.
Claim Objections
Claims 1, 7, 8, and 36 are objected to because of the following informalities:
Claim 1 recites “whereby top gas is generated by said direct reduction furnace; wherein a first stream of direct reduction plant top gas” (emphasis added), claim 7 recites “said first stream of direct reduction furnace top gas” (emphasis added), and claim 8 recites “said direct reduction top gas stream” (emphasis added, no “furnace” or “plant” in the term). It is suggested to maintain consistent terminology for clarity if these limitations are intended to refer to the same gas and/or stream. Applicant' s cooperation is requested in correcting any errors of which applicant may become aware in the consistent terminology of the various gas and streams claimed throughout the instant claims.
Claim 8 recites a “syngas stream” and “the outlet gas stream”. It is suggested to maintain consistent terminology throughout the claims for clarity if these limitations are intended to refer to the same stream.
Claim 36 recites the limitation “pre-heater (36)” which recites reference character “36”, while the rest of the claims do not use reference characters. It is suggested to maintain consistent terminology and style throughout the claims for clarity.
Appropriate correction is required.
Claim Interpretation
The term “comprising” in claim 1 is interpreted as inclusive or open-ended and not excluding additional, unrecited elements or method steps. See MPEP 2111.03(I). The term “consist of” in claim 15 is interpreted as excluding any element, step, or ingredient not specified in the claim. Claim 1 recites “whereby metallurgical gas comprising blast furnace top gas is generated” (emphasis added), which allows for the inclusion of other elements aside from blast furnace top gas, and claim 15 narrows the metallurgical gas composition by reciting the limitation “wherein said metallurgical gas consists of one of blast furnace top gas, blast furnace top gas mixed with other CO-containing gas from the blast furnace plant, and blast furnace top gas mixed with coke oven gas or basic oxygen furnace gas”, which all include the blast furnace top gas introduced in claim 1.
Claim 12 recites the limitation “wherein said fourth stream of metallurgical gas is preheated in said heater, a part thereof being optionally burned in said heater”. The limitation “a part thereof being optionally burned in said heater” is interpreted as optional and therefore not required by the claim. See MPEP 2173.05(h)(2).
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.
Claims 7, 8, 10, 11, 12, 13, 14, and 16 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.
Claims 7 and 10 recite the limitation "the outlet syngas stream" (emphasis added) in lines 3-4 and line 2 respectively. There is insufficient antecedent basis for this limitation in the claim because claim 7 introduces “a syngas stream” in line 3.
Claim 8 depends on claim 7, does not resolve the aforementioned issues, and is thereby also indefinite.
Claim 8 recites the limitation "said outlet stream" in line 4. This limitation renders the claim indefinite. It is unclear whether “said outlet stream” refers to the claimed “outlet syngas stream” of claim 7, to an outlet stream formed from combining the hydrocarbon stream and direct reduction top gas stream of claim 8, or a different interpretation.
Claim 8 recites the limitation "said hydrocarbon stream" in lines 1-2. There is insufficient antecedent basis for this limitation in the claim. Claim 7 recites “hydrocarbon gas upstream of said enriching stage”. It is unclear whether "said hydrocarbon stream" of claim 8 refers to the claimed “hydrocarbon gas upstream of said enriching stage” of claim 7 or to a different hydrocarbon stream.
Claim 8 recites the limitation “said direct reduction top gas stream”. This limitation renders the claim indefinite since it is unclear whether the claimed “said direct reduction top gas stream” refers to the claimed “said first stream of direct reduction furnace top gas” of claim 7 or a different “direct reduction top gas stream”.
Claim 11 recites the limitation “a fourth stream of said metallurgical gas, possibly with a stream of direct reduction plant top gas, is fed to the heat recovery system, optionally with an additional hydrogen stream” (emphasis added). This limitation renders the claim indefinite because it is unclear whether the claimed fourth steam has to include a stream of direct reduction plant top gas and/or an additional hydrogen stream to meet the claim or if the addition of both streams is optional. See MPEP 2173.05(h)(2).
Claim 12 recites the limitation "said reformer". This limitation renders the claim indefinite since it is unclear whether “said reformer” refers to the reformer of the enriching stage recited in claim 11, to the “said reformer or heater device” of claim 1, or to a different reformer.
Claim 13 depends on claim 12, does not resolve the aforementioned issues, and is thereby also indefinite.
Regarding claim 14, a broad range or limitation together with a narrow range or limitation that falls within the broad range or limitation (in the same claim) may be considered indefinite if the resulting claim does not clearly set forth the metes and bounds of the patent protection desired. See MPEP § 2173.05(c). In the present instance, claim 14 recites the broad recitation “reformer or heater device” of claim 1, and the claim also recites “said reformer device” which is the narrower statement of the range/limitation since it narrows to only a “reformer device”. The claim is considered indefinite because there is a question or doubt as to whether the feature introduced by such narrower language is (a) merely exemplary of the remainder of the claim, and therefore not required, or (b) a required feature of the claims. In this case, it is unclear whether the claim requires a heater device, a reformer, a combination, or a different configuration.
Claim 16 recites the limitation "the pre-heater (36)". There is insufficient antecedent basis for this limitation in the claim because a “pre-heater” is introduced in claim 3 and claim 16 depends on claim 1.
Claim Rejections - 35 USC § 102
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 the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
(a)(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention.
Claims 1, 2, and 15 are rejected under 35 U.S.C. 102(a)(1) and 35 U.S.C. 102(a)(2) as being anticipated by US 2004/0226406 A1 of Duarte-Escareno (as cited in prior Office action and in IDS mailed 02/27/2024).
Regarding claim 1, Duarte-Escareno teaches a method and apparatus for improved use of primary energy sources in integrated steel plants (Title, reads on claimed method for producing iron containing products since one of ordinary skill in the art understands steel plants produce iron products). Duarte-Escareno teaches using a blast furnace for pig iron production, charging direct reduced iron, air, coke and iron ore to the blast furnace, and that molten pig iron 46 is produced by reduction of iron ore (claims 1 and 8, [0048], Fig. 1, reads on claimed operating a blast furnace plant to produce liquid pig iron from blast furnace charge material; direct reduced iron and iron ore read on claimed blast furnace charge material since they are charged to the blast furnace in the method of Duarte-Escareno).
Duarte-Escareno reads on the limitation a method for producing iron containing products, comprising: operating a blast furnace plant to produce liquid pig iron from blast furnace charge material of claim 1.
Duarte-Escareno teaches a blast furnace top gas (22, Fig. 1, [0011], [0035], reads on claimed whereby metallurgical gas comprising blast furnace top gas is generated).
Duarte-Escareno reads on the limitation whereby metallurgical gas comprising blast furnace top gas is generated of claim 1.
Duarte-Escareno teaches direct reduction iron (78, Fig. 1) is discharged from the reactor (36, reads on claimed direct reduction plant and direct reduction furnace) and charged to the blast furnace (14, reads on claimed blast furnace plant) ([0052]).
Duarte-Escareno teaches reducing iron oxide-containing solid particles in the direct reduction reactor to metallic iron in the form of direct reduced iron by introducing the solid particles and the heated fourth gas stream into the direct reduction reactor (claim 1, reads on claimed operating a direct reduction plant to produce direct reduced iron products from iron ore; fourth gas stream reads on claimed stream of reducing gas since the fourth gas stream comprises at least a portion of the third gas which has a reducing potential greater than about 0.6 as described in claim 1). Fig. 1 of Duarte-Escareno shows the iron ore 76 loaded into the top of reactor 36, which reads on claimed direct reduction furnace.
Duarte-Escareno therefore reads on the limitation operating a direct reduction plant to produce direct reduced iron products from iron ore loaded into the top of a direct reduction furnace, a stream of reducing gas being introduced into said direct reduction furnace of claim 1.
Duarte-Escareno teaches a heater 30 for heating gas for the direct reduction reactor ([0036], Fig. 1, heater 30 reads on claimed said direct reduction plant comprising a reformer or heater device from which said stream of reducing gas is discharged; the flue gases 82 are discharged from heater 30 as seen in Fig. 1)
Duarte-Escareno therefore reads on the limitation said direct reduction plant comprising a reformer or heater device from which said stream of reducing gas is discharged of claim 1.
Duarte-Escareno teaches reducing gas 94 is withdrawn from reactor 36 and is passed through heat exchanger 88 where some of its sensible heat is used to produce steam 86 from water 89 and thereafter it is treated for regeneration of its reducing potential by cooling and cleaning with water at cooler 96 where water 97 is condensed and separated from the gas stream 94 and passes through CO2 absorber 68 to increase its reducing potential ([0054]; reducing gas 94 reads on claimed top gas is generated by said direct reduction furnace and first stream of direct reduction plant top gas; process through heat exchanger, regeneration, and CO2 absorber reads on claimed enriching stage).
Duarte-Escareno therefore reads on the limitation whereby top gas is generated by said direct reduction furnace; wherein a first stream of direct reduction plant top gas is treated in an enriching stage configured for enriching in gaseous reducing species of claim 1.
Duarte-Escareno teaches reducing gas 94 passes through as excess of purge gas 54 to the blast furnace stoves ([0057], see Fig. 1; blast furnace stoves are part of the claimed blast furnace plant).
Duarte-Escareno therefore reads on the limitation and forwarded to said blast furnace plant to be used therein as reducing gas of claim 1.
Duarte-Escareno teaches a portion 28 of BFG 22 is utilized to heat the reducing gas for the direct reduction reactor in heater 30 ([0036], portion 28 reads on claimed first stream of said metallurgical gas; portion 28 is used in reactor 36 as seen in Fig. 1 and therefore reads on claimed first stream of said metallurgical gas is forwarded to said reformer or heater device of said direct reduction plant to be used therein as fuel gas).
Duarte-Escareno therefore reads on the limitation wherein a first stream of said metallurgical gas is forwarded to said reformer or heater device of said direct reduction plant to be used therein as fuel gas of claim 1.
Regarding claim 2, Duarte-Escareno teaches the method of claim 1 as described above.
Duarte-Escareno teaches blast furnace gas 22 passes through heater 30 via portion 28 and then through stream 84 to the CO2 absorber 68 (see Fig. 1, CO2 absorber 68 reads on claimed enriching stage; gas 22 is used in 68 of Duarte-Escareno and reads on claimed second stream of said metallurgical gas is used as fuel gas in said enriching stage).
Duarte-Escareno therefore reads on the limitation wherein a second stream of said metallurgical gas is used as fuel gas in said enriching stage of claim 2.
Regarding claim 15, Duarte-Escareno teaches the method of claim 1 as described above.
Duarte-Escareno teaches a blast furnace top gas (22, Fig. 1, [0011], [0035], reads on claimed whereby metallurgical gas comprising blast furnace top gas is generated).
Duarte-Escareno therefore reads on the limitation wherein said metallurgical gas consists of one of blast furnace top gas, blast furnace top gas mixed with other CO-containing gas from the blast furnace plant, and blast furnace top gas mixed with coke oven gas or basic oxygen furnace gas of claim 15.
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 3, 5, 6, 11, 12, 13, 14, and 16 are rejected under 35 U.S.C. 103 as being unpatentable over US 2004/0226406 A1 of Duarte-Escareno (as cited in prior Office action and in IDS mailed 02/27/2024), as applied to claim 1 above, in view of "’It All Started in Portland...’ 50 Years Ago" of Kopfle.
Regarding claim 3, Duarte-Escareno teaches the method of claim 1 as described above.
Duarte-Escareno does not explicitly disclose wherein said first stream of metallurgical gas is heated up in a pre-heater upstream of said reformer or heater device and wherein a third stream of said metallurgical gas is combusted in said pre-heater of claim 3.
Kopfle teaches state-of-the-art DRI plants and direct reduction technology (page 13, paragraph below Figure 10). Kopfle and Duarte-Escareno are considered analogous art since they are similarly concerned with direct reduction of iron ore using a direct reduction furnace. Kopfle teaches the inclusion of a reformer and heat recovery system to a DRI shaft furnace (page 8, last paragraph; page 10, Fig. 7; DRI shaft furnace is a direct reduction furnace; reformer is analogous to heater 30 of Duarte-Escareno). Kopfle teaches the reformer produces a high-quality reducing gas without excess steam that can be fed directly into the reduction furnace without need for quenching and reheating, and allows for 2/3 of the top gas from the reduction furnace to be recycled to the reformer where it is mixed with fresh natural gas to produce a carbon monoxide (CO) and hydrogen-rich reducing gas (page 3, last paragraph – page 4, first paragraph). Kopfle teaches adding a heat recovery system comprised of a hot fan and six stages of heat exchangers to reduce overall energy consumption and enhance environmental performance (page 8, Section “ADDING HEAT RECOVERY”). Kopfle teaches preheating the process gas before it enters the reformer tubes (page 6, first paragraph, reads on claimed metallurgical gas is heater up in a pre-heater upstream of said reformer since one of ordinary skill in the art understands a preheating step requires a pre-heater). Kopfle teaches adding combustion air preheat and reformer gas preheat (page 8, Section “ADDING HEAT RECOVERY”, reads on claimed gas is combusted in pre-heater).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to modify the method of Duarte-Escareno to add the preheating step of Kopfle to enable top gas recycling, reduce overall energy consumption and enhance environmental performance, as taught by Kopfle.
Modified Duarte-Escareno therefore reads on the limitation wherein said first stream of metallurgical gas is heated up in a pre-heater upstream of said reformer or heater device and wherein a third stream of said metallurgical gas is combusted in said pre-heater of claim 3.
Regarding claim 5, Duarte-Escareno teaches the method of claim 1 as described above. Duarte-Escareno teaches stream 72, which originates from reducing gas 94 ejected from the reactor 36, is fed to heater 30 ([0047], see Fig. 1, stream 72 reads on claimed second top gas stream).
Modified Duarte-Escareno therefore reads on the limitation wherein a second top gas stream of said direct reduction furnace is fed to said reformer or heater device of claim 5.
Duarte-Escareno does not explicitly disclose wherein a second top gas stream of said direct reduction furnace is fed to said reformer or heater device, with hydrocarbon gas, to form said reducing gas stream introduced in said direct reduction furnace of claim 5.
Kopfle teaches state-of-the-art DRI plants and direct reduction technology (page 13, paragraph below Figure 10). Kopfle and Duarte-Escareno are considered analogous art since they are similarly concerned with direct reduction of iron ore using a direct reduction furnace. Kopfle teaches the inclusion of a reformer and heat recovery system to a DRI shaft furnace (page 8, last paragraph; page 10, Fig. 7; DRI shaft furnace is a direct reduction furnace; reformer is analogous to heater 30 of Duarte-Escareno). Kopfle teaches the reformer produces a high-quality reducing gas without excess steam that can be fed directly into the reduction furnace without need for quenching and reheating, and allows for 2/3 of the top gas from the reduction furnace to be recycled to the reformer where it is mixed with fresh natural gas to produce a carbon monoxide (CO) and hydrogen-rich reducing gas (page 3, last paragraph – page 4, first paragraph; fresh natural gas reads on claimed hydrocarbon gas introduced in direct reduction furnace; see Fig. 7). Kopfle teaches adding a heat recovery system comprised of a hot fan and six stages of heat exchangers to reduce overall energy consumption and enhance environmental performance (page 8, Section “ADDING HEAT RECOVERY”).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to modify the method of Duarte-Escareno to add the fresh natural gas of Kopfle to enable top gas recycling, reduce overall energy consumption and enhance environmental performance, as taught by Kopfle.
Modified Duarte-Escareno therefore reads on the limitation wherein a second top gas stream of said direct reduction furnace is fed to said reformer or heater device, with hydrocarbon gas, to form said reducing gas stream introduced in said direct reduction furnace of claim 5.
Regarding claim 6, Duarte-Escareno teaches the method of claim 1 as described above.
Duarte-Escareno teaches stream 72, which originates from reducing gas 94 ejected from the reactor 36, is fed to heater 30 ([0047], see Fig. 1, stream 72 reads on claimed third top gas stream).
Additionally, or alternatively, addition of a third top gas stream would have been obvious to one of ordinary skill in the art before the effective filing date of the invention of the claimed invention. Mere duplication of parts has no patentable significance unless a new and unexpected result is produced. In re Harza, 124 USPQ 378, 380 (CCPA 1960). Further, it has been held that mere duplication of the essential working parts of a device involves only routine skill in the art. MPEP § 2144.04 VI B.
Modified Duarte-Escareno therefore reads on the limitation wherein a third top gas stream of said direct reduction furnace is used as fuel gas in said reformer or heater device of claim 6.
Regarding claim 11, Duarte-Escareno teaches the method of claim 1 as described above.
Duarte-Escareno does not explicitly disclose wherein said enriching stage comprises a reformer with an integrated heat recovery system, and a fourth stream of said metallurgical gas, possibly with a stream of direct reduction plant top gas, is fed to the heat recovery system, optionally with an additional hydrogen stream of claim 11.
Kopfle teaches state-of-the-art DRI plants and direct reduction technology (page 13, paragraph below Figure 10). Kopfle and Duarte-Escareno are considered analogous art since they are similarly concerned with direct reduction of iron ore using a direct reduction furnace. Kopfle teaches the inclusion of a reformer and heat recovery system to a DRI shaft furnace (page 8, last paragraph; page 10, Fig. 7; DRI shaft furnace is a direct reduction furnace). Kopfle teaches the reformer produces a high-quality reducing gas without excess steam that can be fed directly into the reduction furnace without need for quenching and reheating, and allows for 2/3 of the top gas from the reduction furnace to be recycled to the reformer where it is mixed with fresh natural gas to produce a carbon monoxide (CO) and hydrogen-rich reducing gas (page 3, last paragraph – page 4, first paragraph; fresh natural gas reads on claimed hydrocarbon gas introduced in direct reduction furnace; see Fig. 7). Kopfle teaches adding a heat recovery system comprised of a hot fan and six stages of heat exchangers to reduce overall energy consumption and enhance environmental performance (page 8, Section “ADDING HEAT RECOVERY”). Kopfle teaches adding natural gas, feed gas, top gas fuel, combustion air, and flue gas to the heat recovery system (see Fig. 6, reads on claimed metallurgical gas fed to the heat recovery system).
Additionally, or alternatively, addition of a fourth metallurgical gas stream would have been obvious to one of ordinary skill in the art before the effective filing date of the invention of the claimed invention. Mere duplication of parts has no patentable significance unless a new and unexpected result is produced. In re Harza, 124 USPQ 378, 380 (CCPA 1960). Further, it has been held that mere duplication of the essential working parts of a device involves only routine skill in the art. MPEP § 2144.04 VI B.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to modify the method of Duarte-Escareno by adding the reformer and heat recovery system of Kopfle to enable top gas recycling, reduce overall energy consumption and enhance environmental performance, as taught by Kopfle.
Modified Duarte-Escareno therefore reads on the limitation wherein said enriching stage comprises a reformer with an integrated heat recovery system, and a fourth stream of said metallurgical gas, possibly with a stream of direct reduction plant top gas, is fed to the heat recovery system, optionally with an additional hydrogen stream of claim 11.
Regarding claim 12, modified Duarte-Escareno teaches the method of claim 11 as described above.
Duarte-Escareno does not explicitly disclose wherein a heater is associated with said reformer; and wherein said fourth stream of metallurgical gas is preheated in said heater, a part thereof being optionally burned in said heater of claim 12.
Kopfle teaches preheating top gas fuel and natural gas added to the reducing gas and shaft furnace to reduce energy consumption and reduce temperature loss (page 8, Section “ADDING HEAT RECOVERY”; one of ordinary skill in the art understands preheating requires a heater).
Additionally, or alternatively, addition of a fourth metallurgical gas stream would have been obvious to one of ordinary skill in the art before the effective filing date of the invention of the claimed invention. Mere duplication of parts has no patentable significance unless a new and unexpected result is produced. In re Harza, 124 USPQ 378, 380 (CCPA 1960). Further, it has been held that mere duplication of the essential working parts of a device involves only routine skill in the art. MPEP § 2144.04 VI B.
Modified Duarte-Escareno therefore reads on the limitation wherein a heater is associated with said reformer; and wherein said fourth stream of metallurgical gas is preheated in said heater, a part thereof being optionally burned in said heater of claim 12.
Regarding claim 13, modified Duarte-Escareno teaches the method of claim 12 as described above.
Duarte-Escareno teaches oxygen containing gas, for example air, is injected and combined with gas 72 to further increase the temperature and partial combustion occurs ([0048]-[0048], Fig. 1 shows gas 72 is fed to heater 30; oxygen containing gas reads on claimed oxygen rich stream).
Modified Duarte-Escareno therefore reads on the limitation wherein an oxygen rich stream is fed to said reformer or heater device for combustion of claim 13.
Regarding claim 14, Duarte-Escareno teaches the method of claim 1 as described above.
Duarte-Escareno does not explicitly disclose wherein said reformer device comprises an integrated heat recovery system fed with blast furnace gas of claim 14.
Kopfle teaches state-of-the-art DRI plants and direct reduction technology (page 13, paragraph below Figure 10). Kopfle and Duarte-Escareno are considered analogous art since they are similarly concerned with direct reduction of iron ore using a direct reduction furnace. Kopfle teaches the inclusion of a reformer and heat recovery system to a DRI shaft furnace (page 8, last paragraph; page 10, Fig. 7; DRI shaft furnace is a direct reduction furnace). Kopfle teaches the reformer produces a high-quality reducing gas without excess steam that can be fed directly into the reduction furnace without need for quenching and reheating, and allows for 2/3 of the top gas from the reduction furnace to be recycled to the reformer where it is mixed with fresh natural gas to produce a carbon monoxide (CO) and hydrogen-rich reducing gas (page 3, last paragraph – page 4, first paragraph; fresh natural gas reads on claimed hydrocarbon gas introduced in direct reduction furnace; see Fig. 7). Kopfle teaches adding a heat recovery system comprised of a hot fan and six stages of heat exchangers to reduce overall energy consumption and enhance environmental performance (page 8, Section “ADDING HEAT RECOVERY”). Kopfle teaches adding natural gas, feed gas, top gas fuel, combustion air, and flue gas to the heat recovery system (see Fig. 6, reads on claimed blast furnace gas).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to modify the method of Duarte-Escareno by adding the reformer and heat recovery system of Kopfle to enable top gas recycling, reduce overall energy consumption and enhance environmental performance, as taught by Kopfle.
Modified Duarte-Escareno therefore reads on the limitation wherein said reformer device comprises an integrated heat recovery system fed with blast furnace gas of claim 14.
Regarding claim 16, Duarte-Escareno teaches the method of claim 1 as described above.
Duarte-Escareno does not explicitly teach wherein flues of said enriching stage are forwarded to the pre-heater (36) for heating purposes of claim 16.
Kopfle teaches state-of-the-art DRI plants and direct reduction technology (page 13, paragraph below Figure 10). Kopfle and Duarte-Escareno are considered analogous art since they are similarly concerned with direct reduction of iron ore using a direct reduction furnace. Kopfle teaches the inclusion of a reformer and heat recovery system to a DRI shaft furnace (page 8, last paragraph; page 10, Fig. 7; DRI shaft furnace is a direct reduction furnace). Kopfle teaches the reformer produces a high-quality reducing gas without excess steam that can be fed directly into the reduction furnace without need for quenching and reheating, and allows for 2/3 of the top gas from the reduction furnace to be recycled to the reformer where it is mixed with fresh natural gas to produce a carbon monoxide (CO) and hydrogen-rich reducing gas (page 3, last paragraph – page 4, first paragraph; fresh natural gas reads on claimed hydrocarbon gas introduced in direct reduction furnace; see Fig. 7). Kopfle teaches adding a heat recovery system comprised of a hot fan and six stages of heat exchangers to reduce overall energy consumption and enhance environmental performance (page 8, Section “ADDING HEAT RECOVERY”). Kopfle teaches using the flue gas from the heat recovery system in a hot fan and stack (see Fig. 6, one of ordinary skill in the art understands a hot fan preheats).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to modify the method of Duarte-Escareno by adding the reformer and heat recovery system, including reusing flue gas to preheat, of Kopfle to enable top gas recycling, reduce overall energy consumption and enhance environmental performance, as taught by Kopfle.
Modified Duarte-Escareno therefore reads on the limitation wherein flues of said enriching stage are forwarded to the pre-heater (36) for heating purposes of claim 16.
Claims 7, 8, and 10 are rejected under 35 U.S.C. 103 as being unpatentable over US 2004/0226406 A1 of Duarte-Escareno (as cited in prior Office action and in IDS mailed 02/27/2024), as applied to claim 1 above, in view of "’It All Started in Portland...’ 50 Years Ago" of Kopfle and further in view of US 2004/0216560 A1 of Kepplinger.
Regarding claim 7, Duarte-Escareno teaches the method of claim 1 as described above.
Duarte-Escareno does not explicitly disclose wherein said first stream of direct reduction furnace top gas is combined with hydrocarbon gas upstream of said enriching stage to form a syngas stream, which is fed to said enriching stage, the outlet syngas stream thereof being introduced into said blast furnace, the enriching stage including reformer means of claim 7.
Kopfle teaches state-of-the-art DRI plants and direct reduction technology (page 13, paragraph below Figure 10). Kopfle and Duarte-Escareno are considered analogous art since they are similarly concerned with direct reduction of iron ore using a direct reduction furnace. Kopfle teaches the inclusion of a reformer and heat recovery system to a DRI shaft furnace (page 8, last paragraph; page 10, Fig. 7; reformer reads on claimed reformer means; DRI shaft furnace is a direct reduction furnace). Kopfle teaches the reformer produces a high-quality reducing gas without excess steam that can be fed directly into the reduction furnace without need for quenching and reheating, and allows for 2/3 of the top gas from the reduction furnace to be recycled to the reformer where it is mixed with fresh natural gas to produce a carbon monoxide (CO) and hydrogen-rich reducing gas (page 3, last paragraph – page 4, first paragraph). Kopfle teaches adding a heat recovery system comprised of a hot fan and six stages of heat exchangers to reduce overall energy consumption and enhance environmental performance (page 8, Section “ADDING HEAT RECOVERY”). Kopfle teaches preheating the process gas before it enters the reformer tubes (page 6, first paragraph, reads on claimed metallurgical gas is heater up in a pre-heater upstream of said reformer since one of ordinary skill in the art understands a preheating step requires a pre-heater). Kopfle teaches adding combustion air preheat and reformer gas preheat (page 8, Section “ADDING HEAT RECOVERY”, reads on claimed gas is combusted in pre-heater). It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to modify the method of Duarte-Escareno to add the reformer and heat recovery system with natural gas mixing of Kopfle to enable top gas recycling, reduce overall energy consumption and enhance environmental performance, as taught by Kopfle. One of ordinary skill in the art in the art understands the reducing gas from the mixture of natural gas with top gas of Kopfle is a syngas.
Modified Duarte-Escareno therefore reads on the limitation wherein said first stream of direct reduction furnace top gas is combined with hydrocarbon gas upstream of said enriching stage to form a syngas stream, which is fed to said enriching stage, the enriching stage including reformer means of claim 7.
Regarding the outlet syngas stream introduced into blast furnace of claim 7, Kepplinger teaches a method for producing pig iron from charge materials (Title) and is similarly concerned with direct reduction (see reduction zone 2 in Fig. 1). Kepplinger teaches treating at least a partial stream of top gas from a reduction shaft furnace and introducing it into the blast furnace as reduction gas to improve energy balance and process management (Abstract, claim 11, Fig. 1). It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to modify the outlet stream of modified Duarte-Escareno to reuse in the blast furnace to improve energy balance and process management, as taught by Kepplinger.
Modified Duarte-Escareno therefore reads on the limitation the outlet syngas stream thereof being introduced into said blast furnace.
Regarding claim 8, modified Duarte-Escareno teaches the method of claim 7 as described above.
Duarte-Escareno teaches for the carbonisation process the coke oven furnaces 12 require fuel for heating and coke oven plants have a high flexibility for use of fuels from different sources, including BFG and their own generated COG ([0040]). Duarte-Escareno teaches COG 32, having a high content of hydrogen higher than about 50% by volume and BOFG 60 are used for reduction of iron ores in a DR reactor 36 and have about 31% carbon monoxide by volume ([0047], reads on claimed syngas stream). Duarte-Escareno teaches typical gas compositions for BFG and COG, and treated COG ([0035], [0041], [0044], Table 1, emphasis added).
Kopfle teaches a process without a reformer and heater results in a reducing gas of about 90% H2.
While Duarte-Escareno and Kopfle do not explicitly teach the composition of the outlet gas and slightly different compositions for the syngas stream, the optimization of a result effective parameter is considered within the skill of the artisan. See, In re Boesch and Slaney (CCPA) 204 USPQ 215. This is what research chemists do, optimization of result-effective variables through routine experimentation (MPEP 2144.05 IIA and B). While the typical gas composition of Duarte-Escareno does not fall within the instantly claimed range (i.e. wherein said syngas stream comprises 45 to 55 vol.% H2, 15 to 25% vol.% CO and 7 to 15 vol.% CH4; and said outlet stream comprises above 55 vol.% H2 and above 25 vol.% CO) it is well within the abilities of an ordinary artisan to optimize the amount of hydrogen, carbon monoxide, and methane in the composition depending on the desired carbonization of the final product, as taught by Duarte-Escareno reciting high flexibility of different fuel sources for the carbonization process in the integrated steel plant. As such, one of ordinary skill in the art would have arrived at the instantly claimed range of said syngas stream comprises 45 to 55 vol.% H2, 15 to 25% vol.% CO and 7 to 15 vol.% CH4; and said outlet stream comprises above 55 vol.% H2 and above 25 vol.% CO through no more than routine experimentation. Generally, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. "[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955).
Modified Duarte-Escareno therefore reads on the limitation wherein said hydrocarbon stream combined with said direct reduction top gas stream comprises coke oven gas and wherein said syngas stream comprises 45 to 55 vol.% H2, 15 to 25% vol.% CO and 7 to 15 vol.% CH4; and said outlet stream comprises above 55 vol.% H2 and above 25 vol.% CO of claim 8.
Regarding claim 10, modified Duarte-Escareno teaches the method of claim 7 as described above.
Duarte-Escareno does not explicitly teach wherein preheating of said syngas stream is achieved by heat exchange with the outlet syngas stream downstream of said enriching stage of claim 10.
Kopfle teaches preheating top gas fuel and natural gas added to the reducing gas and shaft furnace using heat exchangers to reduce energy consumption and reduce temperature loss (page 8, Section “ADDING HEAT RECOVERY”).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to modify the process of Duarte-Escareno with the preheating using heat exchangers of Kopfle to reduce energy consumption and reduce temperature loss, as taught by Kopfle.
Modified Duarte-Escareno therefore reads on the limitation wherein preheating of said syngas stream is achieved by heat exchange with the outlet syngas stream downstream of said enriching stage of claim 10.
Citation of Pertinent Prior Art
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
US 2019/0048429 A1 of Vuletic is considered relevant to claims 1, 3-7 and 11-12. Vuletic teaches a method for production of porous iron by a direct reduction process including a DRI reduction device and a COG reformer to obtain reducing gas (Abstract, Fig. 1, claims 1-8).
US 6045602 A of Shah is considered relevant to claim 1. Shah teaches a method for integrating a blast furnace and a direct reduction reactor using cryogenic rectification (Title, reads on claimed blast furnace plant and direct reduction plant).
Conclusion
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/M.A./Examiner, Art Unit 1733
/REBECCA JANSSEN/Primary Examiner, Art Unit 1733
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