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EP4219772A1 - Réduction directe du fer à émission réduite de dioxyde de carbone - Google Patents

Réduction directe du fer à émission réduite de dioxyde de carbone Download PDF

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Publication number
EP4219772A1
EP4219772A1 EP22020024.0A EP22020024A EP4219772A1 EP 4219772 A1 EP4219772 A1 EP 4219772A1 EP 22020024 A EP22020024 A EP 22020024A EP 4219772 A1 EP4219772 A1 EP 4219772A1
Authority
EP
European Patent Office
Prior art keywords
gas
hydrogen
reduction
methane
carbon monoxide
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP22020024.0A
Other languages
German (de)
English (en)
Inventor
Harald Ranke
Volkmar Lemme
Matthias Mayerhofer
Leopold Kloyer
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Linde GmbH
Original Assignee
Linde GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Linde GmbH filed Critical Linde GmbH
Priority to EP22020024.0A priority Critical patent/EP4219772A1/fr
Priority to PCT/EP2023/025038 priority patent/WO2023143870A1/fr
Publication of EP4219772A1 publication Critical patent/EP4219772A1/fr
Withdrawn legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B13/00—Making spongy iron or liquid steel, by direct processes
    • C21B13/0073—Selection or treatment of the reducing gases
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B13/00—Making spongy iron or liquid steel, by direct processes
    • C21B13/0033—In fluidised bed furnaces or apparatus containing a dispersion of the material
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B13/00—Making spongy iron or liquid steel, by direct processes
    • C21B13/02—Making spongy iron or liquid steel, by direct processes in shaft furnaces
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B13/00—Making spongy iron or liquid steel, by direct processes
    • C21B13/08—Making spongy iron or liquid steel, by direct processes in rotary furnaces
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B2100/00—Handling of exhaust gases produced during the manufacture of iron or steel
    • C21B2100/20—Increasing the gas reduction potential of recycled exhaust gases
    • C21B2100/22—Increasing the gas reduction potential of recycled exhaust gases by reforming
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B2100/00—Handling of exhaust gases produced during the manufacture of iron or steel
    • C21B2100/20—Increasing the gas reduction potential of recycled exhaust gases
    • C21B2100/26—Increasing the gas reduction potential of recycled exhaust gases by adding additional fuel in recirculation pipes
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B2100/00—Handling of exhaust gases produced during the manufacture of iron or steel
    • C21B2100/20—Increasing the gas reduction potential of recycled exhaust gases
    • C21B2100/28—Increasing the gas reduction potential of recycled exhaust gases by separation
    • C21B2100/282—Increasing the gas reduction potential of recycled exhaust gases by separation of carbon dioxide
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B2100/00—Handling of exhaust gases produced during the manufacture of iron or steel
    • C21B2100/40—Gas purification of exhaust gases to be recirculated or used in other metallurgical processes
    • C21B2100/44—Removing particles, e.g. by scrubbing, dedusting
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B2100/00—Handling of exhaust gases produced during the manufacture of iron or steel
    • C21B2100/60—Process control or energy utilisation in the manufacture of iron or steel
    • C21B2100/62—Energy conversion other than by heat exchange, e.g. by use of exhaust gas in energy production

Definitions

  • the invention relates to a process for the recovery of metallic iron, in which a methane-rich feedstock is reformed with the supply of carbon dioxide in order to obtain hydrogen and carbon monoxide for the formation of a reducing gas which, with a defined ratio of hydrogen to carbon monoxide, is fed into a reactor charged with iron ore is initiated, where in the direct reduction of iron ore, in addition to metallic iron, a reduction waste gas containing hydrogen, carbon monoxide as well as carbon dioxide and water is produced, from which a carbon dioxide-rich material flow is produced for use in the reforming of the methane-rich charge and a hydrogen and carbon monoxide-containing residual gas for use in the formation of the Reducing gas are separated.
  • the invention relates to a device for carrying out the method according to the invention.
  • a reduction reactor which is usually a shaft furnace, but which can also be designed as a rotary kiln or fluidized bed furnace, is charged with iron ore, which on its way through the reactor is fed with a hot reducing gas containing the reducing agents hydrogen and carbon monoxide is brought into close contact.
  • the iron oxides contained in the ore are reduced to iron by hydrogen and carbon monoxide, resulting in an intermediate product, consisting largely of metallic iron, known as sponge iron, which is discharged from the reduction reactor for further processing into steel.
  • the reducing gas is formed from a crude synthesis gas that is obtained by steam reforming natural gas, with the following overall endothermic reaction taking place: CH 4 + H 2 O ⁇ CO + 3H 2
  • the crude synthesis gas which in addition to hydrogen and carbon monoxide also contains significant amounts of water and about 5 mol % of unreacted hydrocarbons such as methane in particular, is cooled in a first step in order to condense out water before it is mixed with a recycle gas containing hydrogen and carbon monoxide to form the reduction gas .
  • a recycle gas containing hydrogen and carbon monoxide to form the reduction gas .
  • the reducing gas is then heated to a temperature of approx. 1100°C, with which it is entering the reduction reactor.
  • the reducing gas In addition to the two reducing agents, hydrogen and carbon dioxide, which are present in a defined ratio that is optimized for the reduction process, the reducing gas also contains approx. 15 mol % methane, which acts only weakly as a reducing agent and only a small part of which is oxidized in the reduction reactor.
  • a circuit is set up from which, after the removal of dust and water, part of the reduction off-gas is discharged as purge gas in order to prevent the accumulation of inert gases such as nitrogen, which also enters the process with natural gas. to prevent.
  • the purge gas is burned to generate energy for heating the reduction gas and/or for steam reforming
  • the remaining part of the reduction offgas is further dried and acid gas scrubbed into a residual gas consisting predominantly of hydrogen, carbon monoxide and methane, which is used as recycle gas in the formation of the Reducing gas is used, and a carbon dioxide-rich material flow is decomposed, which is released into the atmosphere without further use.
  • a precise analysis shows that approx.
  • the object of the present invention is to specify a method of the generic type and a device for carrying it out, which make it possible to reduce the specific carbon dioxide emission compared to the prior art.
  • the stated object is achieved according to the invention in that hydrogen is produced by electrochemical decomposition of water and/or methane pyrolysis and is used to adjust the hydrogen/carbon monoxide ratio in the reducing gas.
  • the methane-rich feed is only required to provide the carbon monoxide required for the reducing gas, so that a significantly smaller amount of the methane-rich feed is required compared to the prior art. It makes sense to reform the methane-rich use optimized for a high carbon monoxide yield.
  • the reforming can be carried out with a catalyst that supports the dry reforming and the greatest possible supply of carbon dioxide, with no more steam being added than is absolutely necessary for the process, for example to suppress soot formation.
  • the reforming takes place without the addition of steam, completely dry.
  • at least two-thirds of the carbon dioxide present in the reduction off-gas is used in the reforming of the methane-rich feed.
  • the endothermic reforming can be carried out with a reduced supply of heat.
  • the heat is generated by burning a fuel containing carbon - as is usually the case today - this results in significantly lower carbon dioxide emissions than in the prior art.
  • All of the heat required for the reforming of the methane-rich charge is preferably generated by the combustion of at least part of the dried and dedusted reduction waste gas, which is discharged from the reduction gas circuit as purge gas. It is also conceivable to supply at least part of the heat required for reforming the methane-rich feedstock using electricity generated from renewable sources.
  • a crude synthesis gas is produced from the methane-rich charge without the supply of carbon dioxide by steam reforming alone, which has a content of unreacted methane of about 5 mol %.
  • the methane content increases in particular as a result of the separation of water, so that the reduction gas is present with a methane content of approximately 15 mol %.
  • the raw synthesis gas obtained according to the invention by a largely or completely dry reforming also contains unreacted methane, but has significantly less water, so that the reducing gas is present with a much lower methane content for this reason alone.
  • the heating of the reducing gas produced according to the invention can therefore take place with less energy consumption and reduced carbon dioxide emissions compared to the prior art.
  • the part of the purge gas that is not required for providing heat for the reforming of the methane-rich charge is preferably used to heat the reduction gas. It is also possible to use regeneratively generated electricity to heat the reduction gas.
  • the invention relates to a device for the production of metallic iron, with a reformer with which a methane-rich feedstock can be reformed with the supply of carbon dioxide in order to obtain carbon monoxide for the formation of a reducing gas, a reduction reactor which can be charged with iron ore and in which the reducing gas is fed with a defined ratio of carbon monoxide to hydrogen for the direct reduction of iron ore to metallic iron can be fed, as well as a separating device, with which a carbon dioxide-rich substance stream for use in the reforming of the methane-rich charge as well as a hydrogen and Residual gas containing carbon monoxide can be separated for use in the formation of the reducing gas.
  • the object is achieved according to the invention in terms of the device in that it includes a hydrogen source that can generate hydrogen by electrochemical decomposition of water and/or by pyrolysis of methane and can make it available for setting the hydrogen/carbon monoxide ratio in the reducing gas.
  • the hydrogen source preferably comprises an electrolyzer for electrochemical water separation and/or a reactor for carrying out methane pyrolysis, as is known, for example, from the published application DE102019003982A1 is known.
  • the separating device which forms part of a reduction gas circuit, preferably has at least one drying device with which water can be dried, for example by cooling the reduction waste gas below the dew point and separating the water that has condensed out, and a CO 2 - Separation device in which the carbon dioxide-rich material stream and the residual gas containing hydrogen and carbon monoxide can be separated from the cooled reduction waste gas freed from water.
  • a device Downstream of the at least one drying device and upstream of the CO 2 separating device, a device is expediently arranged in the separating device, via which part of the cooled and freed of water reduction waste gas can be discharged from the reducing gas circuit as purge gas.
  • the reformer expediently comprises one or more reformer tubes filled with a catalyst that supports the dry reforming, to which the heat required for reforming the methane-rich charge can be supplied via at least one burner and/or an electric heating device.
  • An advantageous embodiment of the device according to the invention provides for the burner or burners of the reformer to be connected to the separating device in such a way that at least part of the purge gas occurring in the process can be burned to heat the reformer.
  • the device according to the invention preferably comprises a heater through which the reducing gas can be guided and thereby heated.
  • the heater can also be designed with at least one burner and/or an electrical heating device for generating heat and, like this, can be designed in a significantly more compact and cost-effective manner compared to the prior art.
  • Developing the device according to the invention it is proposed to connect the separating device to the heater in such a way that part of the purge gas occurring in the process can be supplied as fuel to at least one burner of the process gas heater.
  • the reduction reactor of the device according to the invention can be designed as a rotary kiln or as a fluidized bed furnace.
  • the reduction reactor is preferably a shaft furnace which can be charged with iron ore from above and from whose lower end sponge iron can be drawn off.
  • a feed device is arranged in its central area, via which hot reducing gas can be introduced into the shaft furnace in order to be brought into intensive contact with the iron ore moving downwards in a fixed bed.
  • the shaft furnace has an extraction device for discharging the reduction waste gas into the separating device.
  • the figure 1 shows a device for reducing iron ore, which can be operated in a preferred variant of the method according to the invention.
  • the reforming is optimized for a high carbon dioxide yield, for which purpose a catalyst is used primarily in the reformer tubes K, which supports the dry reforming and also works reliably in continuous operation when the reformer insert 3 contains little or no steam.
  • a carbon monoxide-rich, water-poor and unreacted methane-containing crude synthesis gas 4 can therefore be drawn off from the reformer R.
  • the heat required for the endothermic reforming process is supplied via burner B1, which converts burner air 5 and a fuel gas 6 containing hydrogen, carbon monoxide and methane into a hot flue gas, which releases a large part of its heat content to the reformer tubes K before it is discharged as cooled flue gas 7 leaves the combustion chamber F of the reformer R.
  • Recycle gas 10 which consists largely of hydrogen, carbon monoxide and methane, as well as hydrogen 11 supplied from the hydrogen source H and advantageously produced without the formation of carbon dioxide by electrochemical decomposition of water and/or methane pyrolysis, is mixed to form the reducing gas 12.
  • the reduction gas 12, in which hydrogen and carbon monoxide are present in a defined ratio, is heated in the heater A before it is introduced into the reduction reactor D via line 13 at a temperature of approx.
  • the heater A is heated via the burner B2, whose hot flue gas generated by the combustion of natural gas 14 and a gas mixture 15 containing hydrogen, carbon monoxide and methane with air 16 gives off heat indirectly to the reducing gas 12 before it is discharged as cooled flue gas 17 into the atmosphere is released.
  • the reduction reactor D preferably designed as a shaft furnace, is charged with iron ore 18, which is brought into intensive contact with the hot reduction gas 13, with the iron oxides present in the iron ore 18 being reduced by hydrogen and carbon monoxide to metallic iron, which is obtained in the form of sponge iron 19 .
  • hydrogen is oxidized to water and carbon monoxide to carbon dioxide
  • the vast majority of the methane contained in the reduction gas 13, which acts only weakly as a reducing agent remains unchanged, so that a reduction waste gas 20 is drawn off from the reduction reactor D, which contains water, carbon dioxide and methane and which consists largely of unreacted hydrogen and carbon monoxide.
  • the reduction exhaust gas is fed into the separating device T, which is part of a reducing gas circuit from which, after the dust and water 21 have been removed in the second drying device W2, part of the dry and dust-free reduction exhaust gas 22 is discharged as purge gas 23 in order to prevent the accumulation of inert gases such as methane and nitrogen, which can also get into the process with the natural gas used.
  • the reformer R Since hydrogen is supplied from the hydrogen source H, the reformer R only has to provide the carbon monoxide required for the reducing gas 12, for which a considerably reduced amount of reformer insert 3 is required compared to the prior art.
  • the fuel gas requirements of the reformer R can therefore be completely covered by the purge gas 23, of which a first part 6 is burned in the reformer R and a second part 15 in the heater A.
  • the part 24 of the reduction off-gas remaining in the reduction gas cycle is, after an optional further drying by means of acid gas scrubbing C, broken down into a residual gas 10 consisting predominantly of hydrogen, carbon monoxide and methane, which is used as recycle gas in the formation of the reduction gas 12, and a material stream 25 rich in carbon dioxide , most of which 2 is used to form the reformer insert 3 while only a small portion 26 escapes to atmosphere.
  • a residual gas 10 consisting predominantly of hydrogen, carbon monoxide and methane, which is used as recycle gas in the formation of the reduction gas 12, and a material stream 25 rich in carbon dioxide , most of which 2 is used to form the reformer insert 3 while only a small portion 26 escapes to atmosphere.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Dispersion Chemistry (AREA)
  • Carbon And Carbon Compounds (AREA)
  • Hydrogen, Water And Hydrids (AREA)
EP22020024.0A 2022-01-28 2022-01-28 Réduction directe du fer à émission réduite de dioxyde de carbone Withdrawn EP4219772A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP22020024.0A EP4219772A1 (fr) 2022-01-28 2022-01-28 Réduction directe du fer à émission réduite de dioxyde de carbone
PCT/EP2023/025038 WO2023143870A1 (fr) 2022-01-28 2023-01-27 Réduction directe de fer avec émission de dioxyde de carbone réduite

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP22020024.0A EP4219772A1 (fr) 2022-01-28 2022-01-28 Réduction directe du fer à émission réduite de dioxyde de carbone

Publications (1)

Publication Number Publication Date
EP4219772A1 true EP4219772A1 (fr) 2023-08-02

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EP22020024.0A Withdrawn EP4219772A1 (fr) 2022-01-28 2022-01-28 Réduction directe du fer à émission réduite de dioxyde de carbone

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EP (1) EP4219772A1 (fr)
WO (1) WO2023143870A1 (fr)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9534265B2 (en) 2014-12-15 2017-01-03 Midrex Technologies, Inc. Methods and systems for producing direct reduced iron incorporating a carbon dioxide and steam reformer fed by recovered carbon dioxide
DE102019003982A1 (de) 2019-06-05 2020-12-10 Basf Se Reaktor mit direkter elektrischer Beheizung
WO2021220555A1 (fr) * 2020-04-27 2021-11-04 Ｊｆｅスチール株式会社 Installation de fabrication de fer et procédé de fabrication de fer réduit

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9534265B2 (en) 2014-12-15 2017-01-03 Midrex Technologies, Inc. Methods and systems for producing direct reduced iron incorporating a carbon dioxide and steam reformer fed by recovered carbon dioxide
DE102019003982A1 (de) 2019-06-05 2020-12-10 Basf Se Reaktor mit direkter elektrischer Beheizung
WO2021220555A1 (fr) * 2020-04-27 2021-11-04 Ｊｆｅスチール株式会社 Installation de fabrication de fer et procédé de fabrication de fer réduit

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WO2023143870A1 (fr) 2023-08-03

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