Improved method for smelting reduction of iron ore

Abstract

A method for improving the sustainability of smelting reduction (SR) of iron ore utilizes a syngas produced by short contact time catalytic partial oxidation (SCT-CPO) in a process utilizing off-gas derived from iron ore reduction, and optionally hydrogen and / or CO and oxygen produced with electrolysis means. The method also uses oxygen produced by cryogenic separation of air or by electrolysis. Syngas produced via SCT-CPO may also be used in blast furnaces and direct reduction processes to reduce iron ore.

Description

Technical Field

[0001] This invention relates to a method for improving the sustainability of molten iron ore reduction (SR). This improved method can also be combined with other methods for iron ore reduction. The improved method utilizes synthesis gas and optionally hydrogen and / or CO and oxygen produced by electrolysis, the synthesis gas being generated by short-contact time catalytic partial oxidation (SCT-CPO) using a gaseous hydrocarbon stream, which includes waste gas derived from iron ore reduction. Background Technology

[0002] Greenhouse gas (GHG) and pollutant emissions from the steel industry remain significant, and ongoing efforts are considering the use of so-called “green” sources, such as “green” electricity and renewable fuels and reactants, to replace fossil fuels. In particular, the use of hydrogen (which is produced through electrolysis utilizing renewable electrical energy resources) is generally considered a preferred molecule for iron ore reduction processes.

[0003] However, it should be noted that producing 1 Nm through electrolysis 3 The production of green hydrogen would require approximately 4.5-5.0 kWh, and the reduction of iron ore would require approximately 50-55 kg of H2 to produce 1 ton of crude steel using the direct reduction (DR) process. This means that an iron ore reduction plant producing 3 MTPY of crude steel would require a power plant of approximately 1 GW. In a rational industrial environment, this is clearly difficult to obtain using electricity from wind turbines, solar panels (which, of course, also have intermittent energy production), or hydropower resources.

[0004] Furthermore, the reduction reaction of iron ore requires high temperatures (typically around 950°C), and while the CO-initiated reduction reaction is slightly exothermic, the corresponding hydrogen-initiated reduction reaction is slightly endothermic. Therefore, using pure renewable hydrogen for the reduction of iron ore would require additional energy. This solution may not be suitable for most iron ore and steel manufacturing scenarios.

[0005] Conversely, integrated processes that utilize renewable energy but also hydrocarbon feedstocks recovered from exhaust emissions from industrial and chemical activities can provide reducing agent gas mixtures, i.e., syngas mixtures, which, when properly produced and used, will allow for reductions in pollutant and greenhouse gas (GHG) emissions and improve energy efficiency under most industrial conditions in iron ore reduction processes.

[0006] This invention relates to a novel method that allows this objective to be achieved in melt reduction (SR) processes that are also integrated with DR processes, blast furnace (BF) processes, and / or other chemical and energy processes.

[0007] Existing technology

[0008] Figure 1A and Figure 1B A process scheme for SR of iron ore according to the prior art is shown.

[0009] Iron ore reduction (SR) is carried out in two steps, either in a reducing shaft furnace or via a fluidized bed reactor array followed by a melting gasifier. Initially, the iron ore is partially reduced to sponge iron in shaft furnace 1 by reducing gas. In the subsequent step, the sponge iron is completely reduced and melted in a melting-gasifier vessel 2. More specifically, granulated iron ore is introduced into reducing shaft furnace 1 or the fluidized bed reactor (in... Figure 1B The reducing gas (represented by 1) is in contact with a reducing gas stream (typically at 800-850°C and 3-5 bar), which is generated in the molten gasifier 2 by substoichiometric combustion of coal. The reducing gas contains 65-70% CO, 20-25% H2 and 2-4% CO2 by volume.

[0010] After leaving the molten gasifier 2, the hot reducing gas is mixed with the recirculated gas from the reducing shaft furnace 1.

[0011] The remaining gas, still possessing a relatively high calorific value, exiting the top of the shaft furnace can be used for other purposes, namely, for generating thermal energy and / or electrical energy and / or for the production of direct reduced iron (DRI).

[0012] The separation between the iron reduction step and the iron melting / gasification step allows for the use of a wide variety of coals and, unlike iron ore reduction processes that use blast furnaces, eliminates the need for coking and sintering equipment.

[0013] like Figure 1A and Figure 1B As shown, the process scheme includes a reduction shaft furnace or high-temperature fluidized bed array in the upper part, while the lower part is used for melting and collecting liquid metal at about 1550°C.

[0014] Coal, limestone, and other inorganic oxides are fed into the upper section of the molten gasifier 2, where they rapidly reach temperatures of 1000-1200°C. Oxygen is introduced into the gasification zone through tuyeres, and carbon monoxide is produced by burning coal. This carbon monoxide, along with the heat of reaction, completes the metal reduction and melting process.

[0015] Furthermore, the use of pure oxygen significantly reduces emissions of NOx and other polluting compounds. Since the gas produced in the melt vaporizer is in excess and has a high calorific value, is rich in carbon monoxide, hydrogen, and CO2, it can be used to generate heat and electricity, or alternatively, sent to another direct reduction (DR) plant.

[0016] The utilization of waste gas generated in iron ore reduction processes is not limited to molten reduction, but also involves other iron ore reduction technologies, such as those using blast furnace (BF) or direct reduction (DR) processes, because these also generate large amounts of gas that cannot be fully reused in the same industrial process. Summary of the Invention

[0017] This invention relates to a novel method for reducing iron ore in a metallurgical plant, and particularly for improving energy efficiency and reducing pollutant and greenhouse gas (GHG) emissions, especially CO2 emissions. This result is achieved through a method for the smelting and reduction of iron ore, comprising the following steps:

[0018] a) Introduce iron ore into at least one pre-reduction furnace or at least one pre-reduction reactor;

[0019] b) The preheated and pre-reduced iron ore and carbonaceous materials are loaded into the melting reduction furnace;

[0020] c) Oxygen is blown into the molten reduction furnace through an array of nozzles located in the lower part of the furnace, thereby further reducing the pre-reduced iron ore and generating exhaust gas.

[0021] d) Introducing the waste gas generated in the molten reduction furnace into the at least one pre-reduction furnace or pre-reduction reactor; and

[0022] e) Discharge the reduced molten iron and slag from the bottom of the molten reduction furnace;

[0023] The characteristic is that the waste gas generated in the melting reduction furnace:

[0024] i) before being introduced into the at least one pre-reduction furnace or pre-reduction reactor, the mixture being partially or completely mixed with the syngas stream, which is generated in a short-contact-time partial catalytic oxidation process using a mixture of hydrocarbon sources as feedstock.

[0025] ii) Partially or completely mixed with the hydrocarbon source used as feedstock for the short contact time-catalytic partial oxidation process.

[0026] According to an aspect of the invention, the oxygen blown into the molten reduction furnace is generated by one or more of the following methods: water electrolysis, carbon dioxide electrolysis, cryogenic separation from air, vacuum pressure swing adsorption or pressure swing adsorption separation from air.

[0027] According to an aspect of the invention, when oxygen is produced by the electrolysis of water and hydrogen is also produced, the hydrogen is mixed with the syngas and introduced into the preheating and pre-reduction furnace along with the syngas and the waste gas produced in the molten reduction furnace for the pre-reduction of the iron ore. Electrolysis can be performed according to any of the following methods: alkaline electrolysis (AE), polymer electrolyte membrane electrolysis (PEME), or solid oxide battery electrolysis (SOEC).

[0028] According to another aspect of the invention, the mixture of the hydrocarbon sources used as feedstock for the SCT-PCO process comprises one or more of the following: natural gas (NG), blast furnace gas (BFG), coke oven gas (COG), direct reducing gas (DRG), basic oxygen furnace gas (BOFG), and other waste gases and / or biogases generated in metallurgical plants and / or other hydrocarbon-containing waste gases generated by chemical and / or refining applications.

[0029] Reduced iron particles produced in the molten reduction furnace can be further processed in an electric arc furnace (EAF, see Treatise on Process Metallurgy, Vol. 3; Chapter 1.5, 2018) or a submerged arc furnace (SAF, see Journal of Sustainable Metallurgy (2018) 4: 77-94).

[0030] The advantage of the method of the present invention is that it can utilize the SCT-PCO process to produce syngas from different mixtures of gaseous reactants, and especially from the waste gas generated by the iron ore reduction process.

[0031] It is worth noting that these feedstocks cannot be utilized by current catalytic syngas production technologies (i.e., steam reforming, autothermal reforming, and combinations of the two (called combined reforming)), and if utilized by non-catalytic technologies (i.e., non-catalytic partial oxidation), they would require much higher oxygen consumption, be less energy efficient, and produce syngas of lower quality.

[0032] In this specification, the molten reduction furnace is also referred to as a "molten gasifier", and the preheating and pre-reduction furnaces refer to shaft furnaces or one or more fluidized beds. Attached Figure Description

[0033] The invention is also described with reference to the accompanying drawings, in which:

[0034] Figure 1A and Figure 1B : Simplified process schemes for existing SR technologies, including (A) vertical furnaces or (B) fluidized bed arrays.

[0035] Figure 2(A): A qualitative plot of the enthalpy / temperature contribution determined by reactions occurring along a tubular reactor with a fixed catalytic bed running at a low mass flow rate [1], [2], [3-4], [5] and [6]; the solid line represents the total enthalpy change.

[0036] (B): A qualitative plot of the enthalpy / temperature contribution determined by the reactions occurring along a truncated cone geometry SCT-CPO reactor with a fixed catalyst bed running at a high-quality flow rate [1], [2], [3-4], [5] and [6]; where the solid line represents the total enthalpy change.

[0037] Figure 3 Schematic diagram of the internal region of an SCT-CPO reactor with a truncated cone reaction zone.

[0038] Figure 4 A simplified SR process scheme is proposed, in which electrolysis produces some of the oxygen required in the molten gasifier, while hydrogen (AE or PEM) and carbon monoxide (SOEC) are mixed with the hot gas produced in the molten gasifier and added to a shaft furnace or fluidized bed array.

[0039] Figure 5 : Simplify the SR process scheme in which iron ore / granules are charged into a shaft furnace or one or more fluidized beds, where partial reduction of iron ore occurs due to the reducing gas stream generated in i) a melt gasifier (2), ii) an AE, PEME, SOEC electrolyzer, iii) a short contact time catalytic partial oxidation reactor, and wherein the oxygen stream generated by the electrolyzer is also added to the melt gasifier and / or the short contact time catalytic partial oxidation reactor.

[0040] Figure 6 A simplified process scheme integrating melt reduction and direct reduction utilizes the reducing gas stream generated in i) a melt gasifier, ii) an AE, PEME, SOEC electrolyzer, and iii) a short-contact-time catalytic partial oxidation reactor, wherein the oxygen stream generated by the electrolyzer is also added to the melt gasifier and / or the short-contact-time catalytic partial oxidation reactor.

[0041] Figure 7 A simplified process scheme integrating molten reduction and blast furnace for iron ore reduction, wherein partial reduction of iron ore occurs due to the reducing gas stream generated in i) molten gasifier (2), ii) AE, PEME, SOEC electrolyzer, and iii) short contact time catalytic partial oxidation reactor, wherein the oxygen stream generated by the electrolyzer is also added to the molten gasifier and / or short contact time catalytic partial oxidation reactor. Detailed Implementation

[0042] This invention provides a methodological solution for further reducing and potentially completely replacing coal in molten reduction. This is achieved by integrating the production of electrolytic hydrogen and oxygen with the production of syngas. The latter is obtained through short-contact-time catalytic partial oxidation (SCT-CPO), which also allows the utilization of waste gases generated from the iron ore reduction process, thereby contributing to a significant reduction in GHG and pollutant emissions and improving the overall energy efficiency of the process.

[0043] The SCT-CPO reactor is particularly advantageous for utilizing a variety of feedstocks that cannot be used as feedstocks in catalytic technologies (e.g., steam methane reforming-SMR and autothermal reforming-ATR) and that would be utilized in a rather inefficient manner by non-catalytic technologies (e.g., partial oxidation-POx).

[0044] The SCT-CPO reactor used in the method of the present invention has certain specific features that make it effective for these applications, whereas different reactors utilizing tubular and fixed bed reactors, fluidized bed, moving bed or boiling bed reactors cannot be used under the conditions described herein.

[0045] SCT-CPO technology has been described in numerous patent documents, including WO2016016257(A1), WO2016016256(A1), WO2016016253(A1), WO2016016251(A1), WO2011151082, WO2009065559, WO2011072877, US2009127512, WO2007045457, WO2006034868, US2005211604, WO2005023710, WO9737929, EP0725038, and EP0640559.

[0046] The following references are cited in scientific and technical publications: Catalysis Today, 106(1-4), p. 34, October 2005; Catalysis Today, 117(4), (2006) 384-393; DOI: 10.1016 / j.cattod.2006.06.043, IntechOpen, http: / / dx.doi.org / 10.5772 / 48708, Ind.Eng.Chem.Res.2013, 52, 17023-17037; https: / / doi.org / 10.1021 / ie402463m.

[0047] The term "short-contact-time catalytic partial oxidation" (SCT-CPO) has a well-defined meaning in scientific, technical, and patent literature. However, as used in this invention, certain aspects are quite specific with respect to combinations of reactor characteristics and operating conditions.

[0048] Improvements have been found in the potential of using specific SCT-CPO reactors and operating conditions to produce syngas for iron ore reduction in molten reduction. It has also been found that molten reduction can be integrated with other processes used for iron ore reduction, particularly those utilizing fluidized bed and moving bed solutions.

[0049] It is worth noting that the SCT-CPO reactor described herein allows for: i) the use of gaseous waste gases emitted from reducing shaft furnaces, fluidized beds, blast furnaces, coke ovens, and alkaline oxygen furnaces; and ii) the use of other feedstocks, such as natural gas, other gases with biomass origin (e.g., biogas), and waste gas feedstocks from other chemical and ore refining industries. Furthermore, this specific SCT-CPO reactor also allows for the use of other CO2-rich feedstocks.

[0050] Furthermore, this particular SCT-CPO reactor requires moderate preheating of the reactant mixture, and the heat required for this moderate preheating can be obtained by recovering heat contained in other waste gas streams and / or recirculated streams, thereby avoiding the use of flame heaters and avoiding the CO2 emissions that would result from such use.

[0051] Regarding the SCT-CPO technology, and in order to explain the unique reactive features that allow for the integration of this technology with the methods of the present invention, the following aspects should be considered.

[0052] In a multiphase catalytic fixed-bed reactor with premixed CH4, steam, CO2, and O2 feed streams, the thermo-chemical properties of the reaction environment generated during SCT-CPO under short contact time conditions are described by considering a system composed of equations [1-5]:

[0053] CH4+2O2=CO2+2H2O ΔH°=-803.0 kJ / mol [1]

[0054] CH4+½O2=CO+2H2 ΔH°=-38 kJ / mol [2]

[0055] CO+H2O→CO2+H2 ΔH°=-41.0 kJ / mol [3]

[0056] CO2+H2→CO+H2O ΔH°=41.0 kJ / mol [4]

[0057] CH4+CO2=2CO+2H2 ΔH°=247.3 kJ / mol [5]

[0058] CH4+H2O=3H2+CO ΔH°=+206 kJ / mol [6]

[0059] The exothermic total oxidation reaction [1] is most likely to occur at the beginning of the bed, while the endothermic steam-CO2 reforming reactions [5] and [6] and the mildly endothermic (RWGS) reaction [4] are most likely to occur in the subsequent zones. Reaction [4] is advantageous over reaction [3] and also over steam-CO2 reforming [5] and [6] by raising the reaction temperature above 830 °C.

[0060] However, it has been found that the extent and location of these reactions within the catalyst bed are greatly influenced by physical and chemical factors. At “relatively low temperatures” (below 750 °C) and under high O2 partial pressures, total combustion [1] is the most competitive reaction on noble metal substrate (Rh, Ru, Ir, Pt, Pd) catalysts.

[0061] These are typically conditions that arise at the beginning of a catalytic bed in a tubular reactor operating at “high” contact time values ​​(e.g., above 1 second). In these cases, the thermal distribution of the reaction environment is found to be determined by strongly exothermic reactions [1] with small contributions from reactions [2], [3] and [4], followed by strongly endothermic steam-CO2 reforming reactions [5] and [6].

[0062] These conditions generate a very large axial temperature gradient, and the energy release associated with total combustion also causes multiphase reactions to propagate into the gas phase, producing fairly non-selective free radical chemical reactions, which in turn lead to the formation of unsaturated molecules and soot.

[0063] It was found that catalytic partial oxidation could not be carried out under high pressure in the case of tubular reactors because the reaction[1] was uncontrollable and propagated into the gas phase with the risk of flame ignition, especially under high pressure (e.g., above 10 ATM), and in any case some free radical reaction would result in the formation of unsaturated hydrocarbon precursors of solid carbonaceous compounds.

[0064] Conversely, it has been found that by utilizing reaction environment geometries that allow contact time at the catalyst bed inlet to be reduced to milliseconds, temperatures of solid catalysts exceeding 1000°C can be achieved while the gas remains relatively cool. This allows for expansion of the reaction volume as temperature and molar flow rate increase with the progress of the reaction. This effect is achieved by employing a truncated conical geometry for the catalyst bed.

[0065] Therefore, it has been found that under these short contact time conditions, the conversion of gaseous hydrocarbons depends largely on the O2 / C ratio and is almost unaffected by the addition of water vapor and CO2. Instead, this addition alters the H2 / CO ratio in the resulting syngas, clearly indicating that reactivity is largely determined by direct partial oxidation[2] and by the RWGS reaction[4].

[0066] Figure 2 Qualitative representations of enthalpy / temperature profiles obtained under (A) low mass velocity, high contact time, and tubular geometry of the catalyst bed and (B) high mass velocity, short contact time, and truncated conical geometry of the catalyst bed are shown.

[0067] Figure 3 The main zones of the SCT-CPO reactor are shown, including the truncated cone reaction zone; these include:

[0068] a) Mixed entrance area,

[0069] b) First thermal shielding preheating zone,

[0070] c) Reaction zone

[0071] d) Secondary thermal shielding,

[0072] e) Reactor outlet area

[0073] Figure 3 The angle α shown is significantly less than 85°, and preferably less than 80°, and preferably between 75° and 30°.

[0074] Other geometric features, namely: i) truncated cone inlet radius R1, ii) truncated cone outlet radius R2, iii) truncated cone length L and catalyst bed packing, are designed to allow the pressure drop (ΔP) inside the catalyst bed to be between 0.1 and 10 ATM, and preferably between 0.5 and 5 ATM.

[0075] For this purpose, the ratio R1 / R2 is between 0.9 and 0.1, and preferably between 0.8 and 0.4, and the shape of the catalyst bed packing is defined by utilizing granular or integral structures and combinations thereof to minimize pressure drop conditions.

[0076] It was also noted that a non-thermal equilibrium exists between the gas and solid phases. This has been explained by considering that the chemical heat generated at the surface and emitted by radiation is absorbed and scattered by the solid much better than by the gas phase, and that this chemical heat is transferred along the catalytic bed from hotter to colder points, thus smoothing the solid surface temperature. The main experimental observations on the thermochemical properties of the SCT environment, to be conducted after optimizing the reaction environment characteristics, are summarized below:

[0077] i) The temperature of the solid phase rises sharply at the beginning of the bed, and the temperature distribution is smoothed by radiation and conduction mechanisms in the axial and radial directions;

[0078] ii) A temperature difference was created between the gas phase and the solid phase;

[0079] iii) The local surface temperature value is higher than the adiabatic temperature; and

[0080] iv) The gas temperature is always lower than the adiabatic temperature and gradually increases from the inlet to the outlet of the bed.

[0081] It has also been found that some of the heat of reaction is transferred toward the reactants entering the first thermal shielding zone, and in this way, the reactants are preheated inside the reactor.

[0082] Therefore, in the method of the present invention, CO2 emissions are primarily related to the energy consumption required for the following:

[0083] - Compressing feedstock (the compression energy required for any syngas production technology),

[0084] -O2 flow is obtained using an air separation unit (ASU).

[0085] - H2 and O2 streams are obtained by steam / water electrolysis.

[0086] The use of specific SCT-CPO reactors, catalysts, and operating conditions provides a unique means of obtaining CO and H2-rich syngas suitable for reduction shaft furnaces using molten gasifier technology, and also suitable for other reactor solutions (such as fluidized bed solutions useful for iron ore reduction). Using specific SCT-CPO reactors can improve the overall efficiency and productivity of SR processes utilizing reduction shaft furnaces or fluidized beds.

[0087] The specific SCT-CPO reactor solution described here utilizes a truncated cone geometry of the catalyst bed and can operate under the following conditions:

[0088] i) Air space velocity values ​​between 30,000 and 500,000 h -1 Between, and preferably between 50,000 and 250,000 h -1 between,

[0089] ii) The inlet temperature of the reactant mixture is between 100 and 450°C, preferably between 150 and 400°C.

[0090] iii) The inlet pressure is between 1.5 ATA and 50 ATA, preferably between 2 and 10 ATA for the purposes of this application.

[0091] The catalyst can be any suitable material, including supports with granular or monolithic structures and active metals on their outer surfaces. Examples of such catalysts (without limiting the possibility of using other materials) are described in WO 2022 / 263409 A1.

[0092] More specifically, the SCT-CPO reactor has: a first inlet section having a cylindrical shape, comprising an inlet, a mixing zone, and a heat-shielding zone; a second section containing a catalyst bed having a truncated conical shape; and a third section having a cylindrical shape with a diameter larger than that of the first cylindrical section, followed by a second heat-shielding zone, wherein:

[0093] a) In the second portion having a truncated cone shape, the upper base plane is smaller than the lower base plane;

[0094] b) The upper base surface of the truncated cone engages with the first cylindrical portion, and the lower base surface engages with the third cylindrical portion; and

[0095] c) The exterior angle (α) of the truncated cone at the upper base plane is less than 85° and preferably less than 75°.

[0096] The use of the specific SCT-CPO reactor solution described herein also allows for the utilization of the oxygen stream obtained through the electrolysis process, thereby further improving the integration between renewable electrical energy and other reactants useful in syngas production.

[0097] These key points will be illustrated with Figures 1 and 4-7.

[0098] As already mentioned, Figures 1(A) and (B) illustrate two simplified schemes of the currently utilized melt reduction process.

[0099] Figure 1(A) The diagram shows lump ore / granules being charged into a preheating and pre-reduction furnace or shaft furnace (1), where partial reduction of the iron ore occurs via a stream of reducing gas generated in a molten reduction furnace or molten gasifier (2). The partially reduced iron ore is charged into the molten gasifier (2) along with carbonaceous material (typically coal). Oxygen is blown into the bottom of the molten gasifier through an array of nozzles or tuyeres. Liquid metal and slag are discharged from the bottom of the molten gasifier. The outlet gas from the shaft furnace 1 passes through a scrubber (5). A portion of the hot gas generated in the molten gasifier (2) passes through a scrubber (4), combines with the outlet gas released from the shaft furnace 1, and is discharged. Dust and water are separated in a settling tank (6).

[0100] Figure 1(B)The currently used process is also described, in which lump ore / granules are loaded into a fluidized bed array (1), where partial reduction of the iron ore occurs via a reducing gas stream generated in a molten gasifier (2). The partially reduced iron ore is loaded into the molten gasifier (2) along with coal. Oxygen is injected at the bottom of the molten gasifier through a tuyer. Liquid metal and slag are discharged at the bottom of the molten gasifier. The outlet gas from 1 passes through a scrubber (5). A portion of the hot gas generated in the molten gasifier (2) passes through a scrubber (4), combines with the outlet gas released from the shaft furnace 1, and is discharged. Dust and water are separated in a settling tank (6).

[0101] Figure 4 An improved process scheme according to an embodiment of the present invention is shown, and it is described how oxygen production using an air separation unit (ASU) can be integrated with the production of oxygen and hydrogen obtained from water or steam using alkaline electrolysis (AE) or polymer membrane electrolysis (PEME), or with the production of oxygen, hydrogen, and carbon monoxide obtained from steam and / or CO2 using solid oxide cell electrolysis (SOEC).

[0102] In more detail, Figure 4 This diagram illustrates how lump ore / granules are first charged into a pre-reduction furnace or pre-reduction reactor or an array of pre-reduction reactors, all indicated as 1, where partial reduction of the iron ore is carried out via a reducing gas stream generated in the molten gasifier 2. The partially reduced iron ore is charged into the molten gasifier 2 along with coal. Oxygen is injected at the bottom of the molten gasifier through a tuyer. Liquid metal and slag are discharged at the bottom of the molten gasifier. The outlet gas from the preheating and pre-reduction unit 1 passes through a scrubber 5. A settling tank (6) is pre-installed to separate dust from water. The oxygen used in the molten gasifier 2 can be generated by an air separation unit 7, by an electrolyzer 10, or by a combination of both. Both a water electrolyzer (AE, PEM, SOEC) and a CO2 electrolyzer can be used. Electrical energy (EE) is used to operate the air separation unit 11 and the electrolyzer 10. The generated H2 (AE, PEM, SOEC) or CO (SOEC) can be added to the hot gas generated in the molten gasifier 2. A portion of the mixed stream can be exported before the washing stage (4).

[0103] Figure 5 Another embodiment of the improved process according to the invention is shown, illustrating how hydrogen and oxygen produced by electrolysis can be integrated into a syngas production process using an SCT-CPO reactor. The feedstock for the SCT-CPO process comprises various hydrocarbon-containing gas sources. This increases the degree of pre-reduction in the shaft furnace 1 and reduces the coal feed rate in the molten gasifier 2. Reducing coal use reduces both GHG emissions and emissions of sulfur pollutants and gaseous unsaturated hydrocarbons or particulate matter.

[0104] In more detail, Figure 5 The process is illustrated by feeding partially reduced iron ore along with coal into a molten gasifier 2. Oxygen is injected at the bottom of the molten gasifier through a tuyer. Liquid metal and slag are discharged at the bottom of the molten gasifier. The outlet gas from 1 passes through a scrubber 5 and is then compressed in a compressor 6. Before compression, a portion of this outlet gas is combusted with other fuels or exhaust gases in a flame heater (7). The outlet gas is preheated in (7) along with other hydrocarbon sources (such as natural gas and biogas), exhaust gases (such as blast furnace gas (BFG), coke oven gas (COG), basic oxygen furnace gas (BOFG), direct reduction gas (DRG), refining exhaust gas, and chemical process exhaust gas). Oxidants such as steam, CO2, and CO2-rich streams are also preheated in a preheater 7. The preheated stream is mixed with an oxygen stream and fed into an SCT-CPO reactor 8. The resulting hot syngas is mixed with the hot top gas from the molten gasifier 2 (after dust removal 3) and fed into the pre-reduction step 1. A portion of the hot mixture can be recycled in the process via scrubber 4. A settling tank 9 is provided to separate dust from water. The oxygen used in the melt gasifier 2 and in the SCT-CPO reactor 8 can be generated by the air separation unit 11, by the electrolyzer (10), or by a combination of both. Both water electrolyzers (AE, PEM, SOEC) and CO2 electrolyzers can be used, and the generated H2 (AE, PEM, SOEC) or CO (SOEC) can be added to the hot synthesis gas stream generated by the SCT-CPO reactor 8.

[0105] Figure 6 Another embodiment of the improved process according to the invention is shown, wherein the gas derived from the SR process can be mixed with other hydrocarbon-containing streams and used in the SCT-CPO process for producing syngas. This syngas is fed into the preheating and pre-reduction shaft furnace of the molten reduction process and into other iron ore reduction processes utilizing fluidized bed technology. The oxygen required for the SCT-CPO process and the molten gasifier can be generated in an air separation unit and / or using AE, PEM, or SOEC electrolysis processes. Hydrogen (AE or PEM) and / or carbon monoxide (SOEC) generated by electrolysis are added to the iron ore reduction reactor along with the syngas.

[0106] In more detail, Figure 6 The partially reduced iron ore from the preheating and pre-reduction step 1 is shown being fed into the molten gasifier 2 along with coal. Oxygen is injected into the bottom of the molten gasifier 2 through a tuyer. Liquid metal and slag are discharged from the bottom of the molten gasifier. The outlet gas from the preheating and pre-reduction shaft furnace 1 passes through a scrubber 5 and is then compressed in a compressor 6. Before compression, a portion of this outlet gas may be burned in a flame heater 7 along with other fuels or exhaust gases.

[0107] This implementation integrates a direct reduction process, in which iron ore is charged from the top of shaft furnace 14. The iron ore is reduced in the shaft furnace by countercurrent reducing gas injected through tuyeres. At the bottom of the shaft furnace, the gas stream is scavenged in scrubber 15 and recycled along with cold methane (NG) to cool and carburize the reduced metal. Direct reducing gas (DRG) exits shaft furnace 14 and passes through scrubber 13. A portion of this gas is available as fuel in preheater 7. The DRG is compressed in compressor 12, mixed with the outlet gas from preheating and pre-reduction shaft furnace 1, and preheated in preheater 7 along with other hydrocarbon sources (such as natural gas and biogas) and waste gases (such as blast furnace gas (BFG), coke oven gas (COG), basic oxygen furnace gas (BOFG), direct reducing gas (DRG), refining waste gas, and chemical process waste gas). Oxidants such as steam, CO2, and CO2-rich streams are also preheated in preheater 7. The preheated stream is mixed with the oxygen stream and fed into the SCT-CPO reactor 8. The resulting hot syngas is diverted and directed to the DR shaft furnace 14, where it is mixed with the top gas from the melt gasifier 2 (after the dust collector 3) and fed into the pre-reduction unit 1. A portion of the hot mixture passes through the scrubber 4 and is recycled in the process. A settling tank 9 is provided to separate dust from water. The oxygen used in the melt gasifier 2 and the SCT-CPO reactor (8) can be generated by the air separation unit 11, by the electrolyzer 10, or by a combination of both. Both water electrolyzers (AE, PEM, SOEC) and CO2 electrolyzers can be used. The generated H2 (AE, PEM, SOEC) or CO (SOEC) can be added to the hot syngas stream generated by the SCT-CPO reactor (8).

[0108] Figure 7 An embodiment of the present invention that integrates SR operation with blast furnace operation is shown.

[0109] The partially reduced iron ore from the preheating and pre-reduction step 1 is fed into the melting gasifier 2 along with coal. Oxygen is injected into the bottom of the melting gasifier 2 through a duct. Liquid metal and slag are discharged from the bottom of the melting gasifier. The outlet gas from step 1 passes through the scrubber 5 and is then compressed in the compressor 6. Before compression, a portion of this outlet gas can be burned in the flame heater 7 along with other fuels or exhaust gases.

[0110] The process is integrated with blast furnace (BF) 14, in which sintered iron ore, limestone, and coke are charged at the top of the blast furnace. Coke is produced from coal in coke oven group 13. Coke oven gas produced from the coke oven group is mixed with blast furnace gas (BFG) exiting BF 14 and compressed in compressor 12. A portion of the mixed gas is used as fuel in preheater 7. The compressed BFG and COG are mixed with the outlet gas from unit 1 and preheated in preheater 7 along with other hydrocarbon sources (such as natural gas and biogas), waste gases (such as basic oxygen furnace gas (BOFG), direct reduction gas (DRG), refining waste gas, and chemical process waste gas). Oxidants such as steam, CO2, and CO2-rich streams are also preheated in preheater 7. The preheated stream is mixed with an oxygen stream and fed into SCT-CPO reactor 8. The generated thermal syngas is diverted and directed to the BF shaft furnace 14, where it is mixed with the top gas from the molten gasifier 2 (after dust removal (3)) and fed into the pre-reduction step 1. A portion of the thermal mixture passes through the scrubber 4 and is recycled in the process. A settling tank 9 is provided to separate dust from water. The oxygen used in the molten gasifier 2, blast furnace 14, and SCT-CPO reactor 8 is generated by the air separation unit 11, the electrolyzer 10, or a combination of both. Both water electrolyzers (AE, PEM, SOEC) and CO2 electrolyzers can be used, and the generated H2 (AE, PEM, SOEC) or CO (SOEC) can be added to the thermal syngas stream generated by the SCT-CPO reactor 8.

[0111] As described above, the advantage of the method of the present invention lies in the use of the SCT-PCO process to produce syngas from a mixture of different gaseous reactants, and particularly from waste gas generated from iron ore reduction processes. This type of feedstock cannot be utilized by current catalytic syngas production technologies (i.e., steam reforming, autothermal reforming, and combinations of both (referred to as "combined reforming")), and if utilized by non-catalytic technologies (i.e., non-catalytic partial oxidation), it would require much higher oxygen consumption, be less energy efficient, and produce syngas of lower quality.

[0112] Furthermore, oxygen obtained from ASU and / or electrolysis is introduced into the gasification zone of the melt gasifier and / or into the SCT-PCO reactor. This contributes to the decarbonization concept of the present invention. In particular, the use of pure oxygen significantly reduces emissions of NOx and other polluting compounds. When oxygen is produced through the electrolysis of water, hydrogen is also generated, which can then be mixed with syngas and used in the preheating and pre-reduction units.

[0113] Since the gas produced in the melt vaporizer is produced in excess and has a high calorific value and is rich in carbon monoxide, hydrogen and CO2, it is used for the generation of heat and electricity or alternatively sent to another direct reduction (DR) plant.

Claims

1. A method for the molten reduction of iron ore, comprising the following steps: a) Introduce iron ore into at least one pre-reduction furnace or at least one pre-reduction reactor; b) The preheated and pre-reduced iron ore and carbonaceous materials are loaded into the melting reduction furnace; c) Oxygen is blown into the molten reduction furnace through an array of nozzles located in the lower part of the furnace, thereby further reducing the pre-reduced iron ore and generating waste gas; d) Introduce the waste gas generated in the molten reduction furnace into the at least one pre-reduction furnace or at least one pre-reduction reactor; and e) Discharge the reduced molten iron and slag from the bottom of the molten reduction furnace; The characteristic is that the waste gas generated in the melting reduction furnace: i) before being introduced into the at least one pre-reduction furnace or pre-reduction reactor, the mixture being partially or completely mixed with the syngas stream, which is generated in a short-contact-time partial catalytic oxidation process using a mixture of hydrocarbon sources as feedstock. ii) Partially or completely mixed with the hydrocarbon source used as feedstock for the short contact time-catalytic partial oxidation process.

2. The method according to claim 1, characterized in that, The oxygen blown into the molten reduction furnace is generated by one or more of the following methods: water electrolysis, carbon dioxide electrolysis, cryogenic separation of air, vacuum pressure swing adsorption or pressure swing adsorption of air.

3. The method according to claim 1 or 2, characterized in that, The oxygen is generated by the electrolysis of water, and the electrolysis also produces hydrogen, which is mixed with the syngas and introduced into the pre-reduction furnace or pre-reduction reactor along with the waste gas generated in the molten reduction furnace for the pre-reduction of the iron ore.

4. The method according to any one of claims 1-3, characterized in that, The electrolysis is performed according to any of the following methods: alkaline electrolysis (AE), polymer electrolyte membrane electrolysis (PEME), and solid oxide battery electrolysis (SOEC).

5. The method according to any one of claims 1-4, characterized in that, The mixture of hydrocarbon sources used as feedstock for the SCT-PCO process comprises one or more of the following: natural gas (NG), blast furnace gas (BFG), coke oven gas (COG), direct reducing gas (DRG), basic oxygen furnace gas (BOFG), and other waste gases generated in metallurgical plants, including waste gases generated by molten gasifiers and / or biogas and / or other hydrocarbon-containing waste gases generated by chemical and / or refining applications.

6. The method according to any one of claims 1-5, characterized in that, The syngas generated by the SCT-CPO process is fed into the pre-reduction shaft furnace or pre-reduction reactor of the molten reduction process and into the direct reduction process of iron ore.

7. The method according to any one of claims 1-5, characterized in that, The syngas generated by the SCT-CPO process is fed into the pre-reduction shaft furnace or pre-reduction reactor of the molten reduction process and into the blast furnace process fed with iron ore to produce reduced iron.

8. The method according to any one of claims 1-7, characterized in that, The waste gas generated in the SR process is mixed with other hydrocarbon-containing streams and used in the SCT-CPO process to generate syngas.

9. The method according to any one of claims 1-7, characterized in that, The short-contact-time catalytic partial oxidation process is carried out in a reactor on a catalyst bed, comprising a portion having a truncated conical geometry, for 30,000-500,000 h. -1 Preferred range: 50,000-250,000 h -1 It operates at the space speed between the air and space.

10. The method according to claim 9, wherein the operating conditions of the short contact time-catalytic partial oxidation process are as follows: -The inlet temperature of the feedstock entering the short contact time-catalytic partial oxidation reactor is 100 to 450°C, preferably 150 to 400°C; The inlet pressure of the reactant mixture in the short-contact-catalytic partial oxidation reactor was 15 kg / cm². 2 Up to 2kg / cm 2 10 kg / cm² is preferred. 2 Up to 2.5 kg / cm 2 And more preferably 6 kg / cm 2 Up to 3 kg / cm 2 .

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