Classifications

• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21B—MANUFACTURE OF IRON OR STEEL
  • C21B13/00—Making spongy iron or liquid steel, by direct processes
  • C21B13/0006—Making spongy iron or liquid steel, by direct processes obtaining iron or steel in a molten state
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21B—MANUFACTURE OF IRON OR STEEL
  • C21B13/00—Making spongy iron or liquid steel, by direct processes
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21B—MANUFACTURE OF IRON OR STEEL
  • C21B13/00—Making spongy iron or liquid steel, by direct processes
  • C21B13/0006—Making spongy iron or liquid steel, by direct processes obtaining iron or steel in a molten state
  • C21B13/0013—Making spongy iron or liquid steel, by direct processes obtaining iron or steel in a molten state introduction of iron oxide into a bath of molten iron containing a carbon reductant
  • C21B13/002—Reduction of iron ores by passing through a heated column of carbon
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21B—MANUFACTURE OF IRON OR STEEL
  • C21B13/00—Making spongy iron or liquid steel, by direct processes
  • C21B13/14—Multi-stage processes processes carried out in different vessels or 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
  • C21B13/14—Multi-stage processes processes carried out in different vessels or furnaces
  • C21B13/143—Injection of partially reduced ore into a molten bath
• • 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
  • C21B2100/28—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
  • C21B2100/60—Process control or energy utilisation in the manufacture of iron or steel
  • C21B2100/64—Controlling the physical properties of the gas, e.g. pressure or temperature
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
  • C21C2100/00—Exhaust gas
  • C21C2100/06—Energy from waste gas used in other processes
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P10/00—Technologies related to metal processing
  • Y02P10/10—Reduction of greenhouse gas [GHG] emissions
  • Y02P10/122—Reduction of greenhouse gas [GHG] emissions by capturing or storing CO2
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P10/00—Technologies related to metal processing
  • Y02P10/10—Reduction of greenhouse gas [GHG] emissions
  • Y02P10/134—Reduction of greenhouse gas [GHG] emissions by avoiding CO2, e.g. using hydrogen

Definitions

• the invention relates to a method for producing molten metal, wherein oxygen, reducing agent and in a reduction reactor reduced iron are introduced into a melter gasifier, the reducing agent gasified with the oxygen and the resulting heat, the reduced iron is melted, the dome gas from the A melt gasifier is used as at least a portion of the reducing gas, and wherein reacted top gas is withdrawn from the reduction reactor, and a plant for carrying out the method, with a reduction reactor, a melt gasifier with oxygen supply and a supply system for reducing agent, at least one conduit for the supply of the dome gas from the melt gasifier into the reduction reactor and at least one line for the removal of the top gas from the reduction reactor.
• blast furnaces various carbonaceous gases, such as natural gas, coke oven gas, etc., are injected via the tuyeres or in the Bosh plane with the background to save coke and increase economy, as already described in GB 883 998 A, for example.
• An injection of blast furnace gas is not economical due to the high CO 2 , N 2 and low H 2 content.
• oxygen is injected at a temperature of 25 ° C and a purity of ⁇ 95% by volume via the nozzles in the melter gasifier to gasify the reducing agent (mainly coal and coal briquettes) and to provide the required heat for the melting of the reduced iron.
• the dome gas of the melter gasifier is used for indirect reduction in a fixed bed reduction shaft (FBRS) or in fluidized bed reactors (ESC). Due to the lack of gas utilization in the FBRS or WSR, there is a high specific coal or coal briquette consumption and a high energy surplus in the export gas.
• the coupling of the melter gasifier operation with the reduction reactor results in a fluctuating metallization of the sponge iron of 70-90%.
• a fluctuating metallization of the sponge iron of 70-90%.
• This reduction also sinks Metallization in the fixed bed reduction shaft or fluidized bed reactor, which in turn causes a fall of the Charbett- and dome temperature in the melter gasifier.
• RAFT adiabatic flame temperature
• the purified export gas which is composed of the top gas from the direct reduction unit and the dome gas from the melter gasifier, has the following typical analysis at 1.5 barg: CO 45% by volume, CO 2 30% by volume, H 2 19% by volume , H 2 O 3 vol% and N 2 3 vol%. Due to the excess gas, it must be recycled and energy optimized.
• the object of the present invention was therefore to provide a process or a plant as described above, in which under increased energy and raw material efficiency and the productivity can be increased, at the same metallurgically better properties of the product are obtained.
• the method according to the invention is characterized in that at least a portion of the withdrawn top gas is introduced into the melter gasifier.
• the melter gasifier By this injection significant savings of coal and coal briquettes are possible as a reducing agent in the melter gasifier, which are replaced by the supply of reductants (CO, H 2 ) from the recirculation gas.
• reductants CO, H 2
• cooling of the vortex zone and the charbet is achieved by deliberate lowering of the flame temperature, which results from the endothermic reaction of the coal, coal briquettes or cokes with the gas constituents and cracking of the methane.
• the recirculated gas is compressed.
• the recirculated gas is cooled between compression and introduction into the melt gasifier, preferably to 30 to 50 0 C, and the carbon dioxide content is reduced, preferably to 2 to 3% by volume.
• the advantage here is a higher gas volume in the charbate for the indirect gas reduction, ie more reduction work in the melter gasifier.
• the Influencing the properties are metered even more accurately in the melter gasifier.
• the recirculated and possibly cooled and carbon dioxide-reduced gas is heated prior to introduction into the melt gasifier, preferably using a partial flow of the recirculated gas as the fuel gas.
• the amount of traceable gas can be maximized without lowering the adiabatic flame temperature (RAFT) below an undesirably low limit with disadvantages for metallurgy. This results in an additional advantageous reduction of the use of raw materials and an additional control of the process.
• RAFT adiabatic flame temperature
• At least a partial flow of the recirculated gas is reformed with higher hydrocarbons and using a further partial flow of the recirculated gas as the fuel gas.
• the reformed recirculated gas with the compressed and / or the cooled and reduced carbon dioxide gas before introduction into the melt gasifier are mixed.
• particles entrained in the dome gas are separated off and returned to the melt gasifier, a partial flow of the gas which has been compressed and / or cooled and carbon dioxide reduced being added for transporting the recirculated particles.
• the theoretical adiabatic flame temperature in the vortex zone is controlled by means of the amount and / or the temperature and / or CO 2 content of the recirculated gas, whereby a targeted control of the metallurgical processes becomes possible.
• the system described above is to solve the problem according to the invention characterized by at least one of the line for the top gas branching and leading into the melt gasifier return line.
• a compressor is inserted in the return line.
• An advantageous embodiment of the plant according to the invention is characterized in that between the compressor and the oxygen supply, a cooling device and a carbon dioxide reduction stage are used, the latter can also reduce or completely eliminate the content of water vapor.
• the output of the compressor and the output of the carbon dioxide reduction stage lead into a common supply line for supplying oxygen to the melter gasifier.
• a heater is provided after the merger of the output of the compressor and the output of the carbon dioxide reduction stage. This results in an additional advantageous reduction of the use of raw materials and an additional control of the process. Due to the advantageous further feature of the invention that the heater works with fuel gas, wherein before the compressor branches off from the return line and leads to the fuel gas connection of the heater, the use of raw materials can be reduced and thus the efficiency of the system can be further increased.
• a reformer can be inserted between the compressor and the oxygen supply.
• the consumption of raw materials can be reduced by, according to an advantageous embodiment, starting from the return line and leading to a fuel gas connection of the reformer.
• Another embodiment of the system according to the invention is characterized in that in parallel branches of the return both a cooling device and a carbon dioxide reduction stage and a reformer are provided, which lead parallel branches in a common supply line for supplying oxygen to the melter gasifier.
• a particle separator is provided in at least one duct for the dome gas, from the particle discharge of which a particle recirculation leads to the melt gasifier, with a branching from the return duct into the particle recirculation.
• a reduction shaft 1 is of lumpy or pellet-shaped iron ore, optionally supplied with unburned aggregates.
• the sponge iron produced in the reduction shaft 1 is introduced into the head of a melter gasifier 3.
• a melter gasifier 3 At the bottom of the melter gasifier 3, liquid pig iron and above it liquid slag accumulate, which are preferably withdrawn discontinuously via their own taps.
• a gasification agent is supplied to the melter gasifier 3, preferably coal and / or coal briquettes, possibly mixed with screened undersize of the iron ore, which otherwise could not be used for the reduction process.
• an oxygen-containing gas is supplied in the lower region of the melter gasifier 3.
• the reducing gas generated is led out of the head of the melter gasifier 3 via a line 6, freed of solid constituents, in particular dust and fine-grained degassed coal, in a hot gas cyclone 7 and then passes via a line 8 into the reduction shaft 1.
• the reducing gas flows through the Pillar of iron ore and additives in countercurrent, thereby reducing the iron ore to sponge iron.
• the separated in the hot gas cyclone 7 degassed pulverized coal and other particulate ingredients are returned to the melter gasifier 3, preferably on entry into this by arranged in the wall of the melter gasifier 3 dust burner, which also oxygen-containing gas is fed, gasified.
• the at least partially consumed reducing gas is withdrawn at the upper end of the reduction shaft 1 via a top gas line 9 and fed to a laundry in the wet scrubber 10 as export gas due to the excess gas utilization and total energy optimization.
• For reducing the pressure of the system used reducing gas is added after washing in the wet scrubber 11 either the export gas or recycled via line 12 as a cooling gas in the line 6 before the hot gas cyclone 7.
• the top gas to be recycled is behind the wet scrubber 10 via a Line 13 is branched off and compressed by means of a compressor 14 with the highest possible suction pressure.
• unused reducing gas downstream of the wet scrubber 11 can be diverted via a further line 15 before admixture with the export gas and recycled.
• the recirculated top gas can according to a first variant after intercooling to 30-50 0 C in the cooler 16 and reduction of the CO 2 content to 2-3% by volume in the system 17 for CO 2 Entfemung introduced via lances 18 in the oxygen nozzles are injected into the melter gasifier 3, wherein the return line for the top gas to the mouth of the oxygen supply is parallel to this. Part of this gas treated in this way can be branched off and admixed for transporting the particles returned from the hot gas cyclone 7.
• the top gas can also be introduced directly, using the sensible compression heat.
• both gas streams can also be mixed.
• the recirculated top gas can also be optionally heated by means of a reduction gas furnace 19 (convective, regenerative), electrical heating, plasma torch or heat exchanger (utilization of the sensible heat of process gas eg top gas before scrubber) after the CO 2 removal.
• a reduction gas furnace 19 convective, regenerative
• electrical heating plasma torch
• heat exchanger utilization of the sensible heat of process gas eg top gas before scrubber
• part of the branched top gas is used via line 20 as the fuel gas.
• the recirculated top gas may also be reformed with higher hydrocarbons (e.g., natural gas) in a reformer 21, with part of the top gas supplied as a fuel gas via a conduit 22 being used for the endothermic heat of reaction.
• higher hydrocarbons e.g., natural gas
• the increased amount of reducing gas from the melter gasifier 3 due to the gas recirculation is used to increase production in the reduction stage 1 (shaft or fluidized bed) and / or for a constant metallization.
• the constant metallization is achieved by the decoupling of the melter gasifier 3 and the reduction shaft 1. Any time sufficient amount of reducing gas allows a constant metallization in the reduction shaft 1.
• no major changes in the meltdown carburetor 3 supplied oxygen amount to adjust the heat balance necessary, resulting in a constant Charbettemperatur, lower coal decomposition and thus stable operation of the melter gasifier 3 with low specific reducing agent consumption leads.
• An optimization of the melter gasifier operation leads to a smaller necessary amount of reducing agents for the fixed bed reduction shaft 1 (FBRS) or in fluidized bed reactors (WSR) of the plant, which is fully compensated by the return of top gas.
• FBRS fixed bed reduction shaft 1
• WSR fluidized bed reactors

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Manufacturing & Machinery (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Manufacture Of Iron (AREA)
• Waste-Gas Treatment And Other Accessory Devices For Furnaces (AREA)
• Hydrogen, Water And Hydrids (AREA)

Applications Claiming Priority (2)

Publications (1)

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• 2006
  • 2006-10-13 DE DE102006048601A patent/DE102006048601A1/de not_active Withdrawn
• 2007
  • 2007-10-01 CN CNA2007800376484A patent/CN101528948A/zh active Pending
  • 2007-10-01 WO PCT/EP2007/008514 patent/WO2008046503A1/de active Application Filing
  • 2007-10-01 EP EP07818594A patent/EP2082066A1/de not_active Withdrawn
  • 2007-10-01 KR KR1020097008757A patent/KR20090068351A/ko not_active Application Discontinuation
  • 2007-10-01 AU AU2007312665A patent/AU2007312665A1/en not_active Abandoned
  • 2007-10-01 MX MX2009003725A patent/MX2009003725A/es unknown
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  • 2007-10-01 BR BRPI0719172-3A2A patent/BRPI0719172A2/pt not_active IP Right Cessation
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  • 2007-10-01 US US12/445,349 patent/US20100024599A1/en not_active Abandoned
  • 2007-10-01 JP JP2009531734A patent/JP2010506046A/ja active Pending
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  • 2007-10-03 TW TW096136997A patent/TW200827452A/zh unknown
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