EP1275739A2 - Process and apparatus for metal production, especially steel, from fine grained metal oxides - Google Patents

Abstract

The assembly for the direct production of a metal, e.g. steel, from a fine grain metal oxide (1), especially a fine ferrous ore, feeds the metal oxide into a reduction reactor (3). In the reactor, the ore is at least partially reduced by a reduction gas mainly of H2, preferably at least 90 vol.% H2. The partially reduced ore is passed into a smelting reactor (4), preferably to give molten steel. A carrier gas flows through the reduction reactor, as a transport reactor, working in a temperature range of 500-900 degrees C.

Description

The invention relates to a plant and a method for metal production, preferably for direct steelmaking, of fine-grained metal oxide, in particular iron-containing ore, wherein the metal oxide introduced into a reduction reactor and in this reduction reactor by a predominantly formed from H ₂ , preferably at least 90% by volume H. ₂ -containing, reducing gas is at least partially reduced, and subsequently in a melt reactor, preferably to steel, is melted.

The experts have been trying for a long time the possibilities and advantages of Hydrogen metallurgy to use. Furthermore, it is known in the art, the am Commodity market sufficiently available fine ore as replacement of lump ore in the To use pig iron or steel production. The specialist is in particular various methods and apparatus for producing pig iron and / or steel known from fine ore.

In the patent publication EP00106747A1, a method is taught in this context by which preheated iron ore dust in a co-current gas mixture predominantly containing H _{2 is} reduced. In practice, the learned method proves to be uneconomical due to the high energy input.

It is therefore an object of the present invention, a method according to the The preamble of claim 1 and a system according to the preamble of claim 9 continue to develop, through which a cost-effective and resource-saving Production of steel from fine ore can be realized.

It is a further object of the present invention to overcome the disadvantages of the prior art Technology to overcome.

This object is achieved by a method according to the characterizing Part of claim 1, and by an annex according to the characterizing part of Claim 9 solved.

The use of a transport reduction reactor is distinguished from the Operation of a conventional shaft furnace, as taught in EP00106747A1, especially characterized in that, for example, by the more uniform distribution of the starting materials in the reducing gas, an energetically and / or kinetically more favorable course of the Reduction can be achieved. In this way, you will have significant energy costs saved.

The operation of a transport reduction reactor is different Embodiments especially characterized in that the fine-grained Feedstock in the directed transport gas stream of the transport reduction reactor is brought in and transported by this.

A transport reduction reactor provides a particular embodiment Reactor for the reduction of metal oxide with a transporting carrier gas.

As a carrier gas can according to a preferred embodiment of the invention Process any suitable gas, in particular an at least partially inert gas be used. According to a preferred embodiment of the invention is as Carrier gas used an at least partially reducing gas. For example the composition of the carrier gas not for at least partial reduction of the metal ore in the transport reduction reactor is sufficient for a supply of sufficient amount of reducing gas in the transport reduction reactor to to care.

By using hydrogen as, preferably sole, reducing agent, the CO ₂ emission is reduced or, ideally, completely prevented. After reduction, the partially consumed reducing gas contains H ₂ O in addition to H ₂ , which significantly simplifies the treatment of exhaust gas compared to systems in which, for example, a CO and H ₂ -containing reducing gas is used.

The inventive method is characterized by its particularly economical Operating mode, as feedstocks fine ore and as reducing agent hydrogen be used. Hydrogen is currently cheap from natural gas or coal too produce. In the future, an economic production of hydrogen by means of Electrolysis or succeed in bioreactors.

According to one embodiment of the invention, at least part of the carrier gas of the Transport reduction reactor, in particular of the reducing gas, in the region of the feed of the metal oxide in the transport reduction reactor in one, in particular at least partially directed upward, directed flow, with the, in particular by the, meeting of the directed carrier gas flow with the supplied Metal oxide in the transport reduction reactor, the metal oxide in the Transport reduction reactor, preferably in the carrier gas stream, is finely divided.

According to a further embodiment of the method according to the invention are Metal oxide particles at least partially by the carrier gas against gravity transported. This form of transport leads to a particularly advantageous Distribution of the metal oxide particles, as well as a particularly efficient reduction the same.

According to the invention, according to a preferred embodiment, a fine Distribution of the metal oxide in the carrier gas stream, in particular the Reduction gas stream is provided, one over the prior art significantly faster and more complete reduction of the fine metal oxides can be achieved.

The introduction of the metal oxide in the transport reduction reactor itself can on different types take place. In this regard, embodiments are with, on or in the Transport reduction reactor arranged, injectors and / or feeding devices possible, in each case the metal oxide in or against the flow direction of the Carrier gas stream, in particular the reducing gas stream, bring in this.

The role of the metal oxide in the carrier gas flow may be at different angles take place, for example, under 135 ° (225 °) or 120 ° (210 °) against the Flow direction (0 ° corresponds to flow direction).

According to another preferred embodiment of the method according to the invention For example, the reduction in the transport reduction reactor is below a temperature of 1000 ° C, preferably at a temperature of 500 to 900 ° C, more preferably from 700 to 900 ° C, carried out.

According to a further preferred embodiment of the method according to the invention, the fine-grained metal oxide is introduced with a further carrier gas into the transport reduction reactor, in particular injected under pressure, wherein the further carrier gas preferably at least 50 vol% H ₂ , more preferably at least 75 vol% H ₂ , in particular at least 90 Vol% H ₂ , contains.

According to one embodiment of the method according to the invention, in the essential solid-shaped. Metal oxide through the transport reduction reactor to a Gas-solid separation device, in particular a cyclone, transported before the at least partially reduced metal oxide in a melt reactor, in particular to liquid steel, is melted.

According to a preferred embodiment, the fine distribution of the metal oxide in the carrier gas, in particular in the reducing gas, the transport reduction reactor below a separation of the solid in a gas-solid separation device intended. After separation, the at least partially reduced metal oxide for example, introduced into a melt reactor and processed into liquid steel become.

By a method of this kind, direct steelmaking is particularly efficient Form, in particular in only one process stage, feasible.

According to a further preferred embodiment of the method according to the invention, the reduction gas, which in turn is at least partially purified of solid particles in the gas-solid separation apparatus, is subjected to gas treatment, whereby impurities, in particular H ₂ O, are at least partially separated, and possibly used H _{2 is} at least partially replaced ,

According to a particularly preferred embodiment of the method according to the invention a complete replacement of the spent H _{2 is} provided. This prevents harmful accumulation of the reducing gas in H ₂ O in the system.

According to another preferred embodiment of the method according to the invention is the separated in the gas-solid separation device, at least partially reduced, metal oxide from the gas-solid separation device, in particular by a hydrogen flow pump, sucked off.

A hydrogen flow pump is by definition one Pump for introducing reducing gas and fine solid into a reaction vessel, in a preferred embodiment analogous to a water jet pump is working. In the simplest case, such a hydrogen flow pump, for example by a, flowed through by hydrogen, venturi realized in the by Exploitation of the pressure difference due to the different Flow cross sections creates a pumping effect and in a simple way the fine Solids, for example, the finely particulate metal oxide, sucked and in the appropriate vessel and / or introduced into the corresponding reactor can.

According to another preferred embodiment of the method according to the invention the at least partially reduced metal oxide is introduced into a melt reactor, and under the action of a plasma torch and / or an electric arc melted.

According to a preferred embodiment of the method according to the invention, an H ₂ -containing gas is fed to the melt reactor, which is optionally at least partially ionized in the melt reactor and optionally subsequently introduced as reducing gas into the transport reduction reactor.

In this case, for example, by ionization of the H ₂ gas, a hot plasma is generated for melting the fine-grained metal oxides.

According to a particular embodiment of the present invention, energy and costs are saved by using the, preferably hot, H ₂ -containing exhaust gas of the melt reactor as transport gas and carrier gas of the transport reduction reactor.

According to another preferred embodiment of the method according to the invention is in the melt reactor less than 50% by volume, in particular less than 10% by volume, the, used in the reduction chamber, carrier and / or reducing gas introduced, and for example from the melt reactor in the Transport reduction reactor, preferably as a carrier gas and / or reducing gas converted.

According to another preferred embodiment of the method according to the invention is the amount of metal oxide which enters the transport reduction reactor is introduced, and / or the flow and / or amount of the carrier and / or Reduction gas in the transport reduction reactor itself by a Hydrogen flow pump, and / or a corresponding one of the prior art known device, regulated.

According to another preferred embodiment of the method according to the invention The liquid steel is continuously, for example, via an inductive pump and a Siphon, discharged from the smelting reactor.

According to another preferred embodiment of the method according to the invention the slag is discharged in batches from the melt reactor.

The invention is further characterized by a device according to claim 9.

According to a preferred embodiment of the device according to the invention is Carrier gas supply and / or the transport reduction reactor designed such that in the Reduction chamber in the area of the feed of the metal oxide a directed Carrier gas flow is adjustable, and is further the solids supply of the reduction chamber carried out such that the metal oxide is at least partially initiated by introducing In particular blowing, in the at least partially directed carrier gas stream of the Transport reduction reactor is finely distributed. In one embodiment, this takes place with, in particular by, the coincidence of the metal oxide with the im Transport reduction reactor prevailing carrier gas flow a fine distribution of Metal oxides in the carrier gas.

According to a further preferred embodiment of the device according to the invention the transport reduction reactor has an opening through which the reducing gas together with the at least partially reduced, substantially solids-shaped, Metal oxide from the transport reduction reactor is derivable.

According to a further preferred embodiment of the apparatus according to the invention, the solid feed is carried out in a manner which makes it possible to adjust the substantially solid-shaped metal oxide, preferably controllably, by a further carrier gas which is at least 50% by volume, preferably at least 90% by volume. from, optionally hot, H ₂ consists, to introduce into the transport reduction reactor.

According to a further preferred embodiment of the device according to the invention is the reducing gas together with the at least partially reduced, im essential solid-shaped, metal oxide from the transport reduction reactor in a Gas-solid separation device can be introduced, which has a lining, the compared to a hot reducing gas, the more than 50% by volume, in particular to more than 90% by volume, composed of hydrogen gas, is stable.

According to a further preferred embodiment of the device according to the invention the gas-solid separation device is arranged and / or formed such that the fine-grained metal oxide at least partially by the, in the Transport reduction reactor prevailing, directed carrier gas flow, in particular Reduction gas stream can be introduced into the gas-solid separation device.

According to a further preferred embodiment of the device according to the invention closes the gas-solid separation device as a communicating vessel, in particular directly, to the transport reduction reactor.

According to a particular embodiment, the gas-solid separation device, preferably without locks or similar devices, directly on the Transport reduction reactor, or at least partially in the transport reduction reactor arranged.

According to a further preferred embodiment of the device according to the invention is after the gas-solid separation device a melt reactor for Melting and optionally Fertigreduzieren, of, at least partially pre-reduced, metal oxides, arranged.

According to a further preferred embodiment of the device according to the invention is for introducing the deposited in the gas-solid separation device Metal oxides in the melt reactor, a hydrogen flow pump, and / or a similar device, arranged.

According to a further preferred embodiment of the device according to the invention is the melt reactor, a plasma torch and / or an electrode for generating a arranged electric arc.

According to a further preferred embodiment of the device according to the invention is the transport reduction reactor directly, for example as with the Melting reactor communicating vessel, arranged after the melt reactor.

According to a further embodiment of the device according to the invention is the Transport reduction reactor in a manner at the melt reactor, in particular immediately thereafter arranged, which makes it possible, at least partial thermal, flow of the gas occurring in the melt reactor at least partially as a directed flow, preferably as a carrier gas flow, in the Continue transport reduction reactor.

In a particular embodiment, the transport reduction reactor is without Locks or similar devices are arranged directly on the melt reactor.

According to an additional embodiment of the device according to the invention is on Melting reactor and / or at the transport reduction reactor a Hydrogen flow pump and / or a corresponding device arranged, the it makes it possible to control the gas flow rate in the transport reduction reactor.

According to an additional embodiment of the invention prevails in the region of the gas-solid separation device a lower pressure than in the area of the melt reactor. Thus, the gas flow is ensured by the transport reduction reactor.

Fig. 1 zeigt eine Vorrichtung sowie ein Verfahren zur direkten Erzeugung von flüssigem Stahl aus Feinerz

The method according to the invention and the device according to the invention will be explained in more detail below schematically with reference to a non-limiting drawing.

Fig. 1 shows an apparatus and a method for the direct production of liquid steel from fine ore

Hereinafter, a continuous process will be described with which Fine ore, with a typical grain size distribution (<50 μm) for pellet plants in one Process stage and with hydrogen as a reducing agent in liquid steel can be converted.

To simplify the description, the process is divided into individual process steps disassembled. These run simultaneously in a single reaction vessel consisting of a meltdown part, a transport reduction reactor, and optionally integrated gas-solid separators, starting from. The reaction vessel is like this procure that in individual parts of the same defined process steps run continuously.

Input materials to the plant for the production of steel are fine ore 1 and hydrogen. Starting materials are liquid steel, liquid slag and a gas mixture of H ₂ and H ₂ O).

1. In ein senkrechtes Rohr 3, welches an seinem unteren Ende mit dem Einschmelzteil 4 des Reaktionsgefäßes verbunden ist und durch welches heißes Reduktionsgas 5, das aus dem Einschmelzteil 4 kommt, strömt, wird seitlich Feinerz 1 mit heißem Wasserstoff 6 eingeblasen und durch den Gasstrom nach oben transportiert. Das heiße Reduktionsgas 5 aus dem Einschmelzteil 3 und der heiße Wasserstoff 6, der zum Einblasen des Feinerzes 1 verwendet wird, vermischen sich und werden so dosiert, dass im Rohr 3 eine Gastemperatur von 800 bis 900 C herrscht. Die Geschwindigkeit des im Rohr 3 nach oben strömenden Gases wird so bemessen, dass das eingeblasene Feinerz 1 vollständig nach oben transportiert wird. Die Länge des Rohres 3 ist so bemessen, dass auf dem Weg der Feinerzteilchen von der Einblasestelle bis zum Rohrende die Reduktion der Feinerzteilchen zu direkt reduzierten Eisenteilchen erfolgt (Prinzip des Transportreduktionsreaktors).

2. Am oberen Ende des senkrechten Rohres 3 befinden sich eine Anzahl von Abscheidezyklonen 7, in dem die direkt reduzierten Eisenteilchen abgeschieden werden. Das vom Feststoffanteil getrennte Gasgemisch (H₂,H₂O mit Verunreinigungen) 15 wird einer Gasaufbereitung 8 zugeführt. In der Gasaufbereitung wird H₂ 9 von H₂O 10 gereinigt und getrennt, sowie der im Prozess verbrauchte H₂ ergänzt. Der Wasserstoff wird dem Prozess wiederum zugeführt.

3. Das in dem Abscheidezyklon 7 abgeschiedene direkt reduzierte Eisen wird mittels Wasserstoffströmungspumpen abgesaugt und durch einen Plasmabrenner 11 oder eine Lichtbogenelektrode in den Schmelzreaktor 4 eingeblasen. Die direkt reduzierten Eisenteilchen werden im Plasma des Plasmabrenners 11 bzw. durch den Lichtbogen geschmolzen und sammeln sich mit der Schlacke am Boden des Einschmelzteiles 4. Das heiße Reduktionsgas (ca. 1600 C) 5 entweicht dem Einschmelzteil 4 über das Rohr 3 des Transportreduktionsreaktors. Die Gasströmungsmenge, die aus dem Schmelzreaktor austritt wird mittels Wasserstoffströmungspumpen eingestellt.

4. Der flüssige Stahl im Einschmelzteil kann kontinuierlich abgestochen (Kombination aus induktiver Pumpe und Siphon) werden. Die Schlacke wird chargenweise aus dem Einschmelzteil 4 über konventionelle Abstichmethoden ausgetragen.

Steps:

1. In a vertical tube 3, which is connected at its lower end with the melt-in part 4 of the reaction vessel and through which hot reducing gas 5, which comes from the meltdown 4 flows laterally fine ore 1 is injected with hot hydrogen 6 and through the gas stream transported to the top. The hot reducing gas 5 from the melt-in part 3 and the hot hydrogen 6, which is used for blowing in the fine ore 1, mix and are metered so that in the tube 3, a gas temperature of 800 to 900 C prevails. The velocity of the gas flowing upwards in the tube 3 is dimensioned such that the injected fine ore 1 is transported completely upwards. The length of the tube 3 is dimensioned such that on the way of the fine ore particles from the injection point to the tube end, the reduction of the fine ore particles to directly reduced iron particles takes place (principle of the transport reduction reactor).

2. At the upper end of the vertical tube 3 are a number of Abscheidezyklonen 7, in which the directly reduced iron particles are deposited. The separated from the solid fraction gas mixture (H ₂ , H ₂ O with impurities) 15 is fed to a gas treatment 8. In the gas treatment, H ₂ 9 is purified and separated from H ₂ O 10, and the H ₂ consumed in the process is supplemented. The hydrogen is in turn fed to the process.

3. The directly reduced iron deposited in the precipitation cyclone 7 is sucked off by means of hydrogen flow pumps and blown into the melt reactor 4 through a plasma torch 11 or an arc electrode. The directly reduced iron particles are melted in the plasma of the plasma torch 11 or by the arc and collect with the slag at the bottom of the meltdown part 4. The hot reducing gas (about 1600 C) 5 escapes the meltdown part 4 via the pipe 3 of the transport reduction reactor. The amount of gas flow exiting the melt reactor is adjusted by means of hydrogen flow pumps.

4. The liquid steel in the meltdown part can be tapped continuously (combination of inductive pump and siphon). The slag is discharged in batches from the meltdown part 4 by conventional tapping methods.

Furthermore, a number of heat exchangers 12, which are advantageous for Configuration of the heat balance of the described method are useful, and Compressor 13 attached. Furthermore, a strip casting plant 14 is preferred continuous processing of the liquid steel, a surge tank for draining the steel and / or slag from the meltdown 4, as well as a Fine ore jar 2 outlined.

• Direkte Stahlerzeugung in nur einer Prozessstufe und damit geringe Investitions- und Umwandlungskosten.
• Billige Einsatzstoffe: Feinerz (Pelletfeed) und als Reduktionsmittel Wasserstoff, der derzeit kostengünstig aus Erdgas oder Kohle und künftig eventuell mittels Elektrolyse oder Bioreaktoren erzeugt werden kann.
• Umweltfreundlich durch Verringerung des CO₂ Ausstoßes - Nebenprodukte sind lediglich Schlacke und Wasser
• Prozessgasrezyklierung und optimale Energienutzung - Kürzeste Produktionszeit

Advantages of the procedure:

• Direct steel production in just one process stage and thus low investment and conversion costs.
• Cheap feedstocks: fine ore (pelletfeed) and as reducing agent hydrogen, which can currently be produced inexpensively from natural gas or coal and in the future possibly by means of electrolysis or bioreactors.
• Environmentally friendly by reducing CO ₂ emissions - by-products are just slag and water
• Process gas recycling and optimal energy utilization - shortest production time

Claims (15)

Process for the production of metals, preferably for direct steelmaking, from fine-grained metal oxide, in particular iron-containing fine ore, wherein the metal oxide is introduced into a reduction reactor and at least partially reduced in this reduction reactor by a reducing gas formed predominantly from H ₂ , preferably at least 90% by volume H ₂ -containing is reduced, and the at least partially reduced metal oxide is subsequently melted in a melt reactor, preferably to steel, characterized in that a transport reduction reactor is used as a reduction reactor, wherein the transport reduction reactor is flowed through with a carrier gas. A method according to claim 1, characterized in that at least a portion of the carrier gas, in the region of, preferably lateral, introduction of the metal oxide in the transport reduction reactor in a, in particular upward, directed flow, wherein, with the coincidence of the directed carrier gas stream with the metal oxide in the transport reduction reactor, the metal oxide is finely dispersed in the transport reduction reactor, preferably in the carrier gas. A method according to claim 1 or 2, characterized in that the reduction in the transport reduction reactor at a temperature of 500 to 900 ° C is performed. Method according to one or more of claims 1 to 3, characterized in that the fine-grained metal oxide is introduced with a further carrier gas into the transport reduction reactor, in particular injected under pressure, wherein the further carrier gas at least 50 vol% H ₂ , preferably at least 90 vol% H ₂ , contains. Method according to one or more of claims 1 to 4, characterized in that the, essentially solid-shaped, metal oxide is transported through the transport reduction reactor to a gas-solid separation device, in particular a cyclone. A method according to claim 5, characterized in that in the gas-solid separation device in turn separated from solid particles reducing gas is subjected to gas treatment, wherein impurities, in particular H ₂ O, are separated, and optionally used H _{2 is} at least partially replaced. Method according to one or more of claims 1 to 6, characterized in that the at least partially reduced metal oxide is introduced into a melt reactor, and, preferably under the action of a plasma torch and / or an electric arc, is melted. A method according to claim 7, characterized in that the melt reactor, an H ₂ -containing gas is supplied, which is at least partially ionized in the melt reactor and / or subsequently introduced as a carrier and / or reducing gas in the transport reduction reactor. Plant for metal production, preferably for direct steelmaking, of fine-grained metal oxide, in particular iron-containing fine ore, preferably for carrying out a process according to one or more of claims 1 to 8, wherein a reduction reactor with at least one reducing gas inlet and a reducing gas discharge, as well as with a solids supply, for supplying the metal oxide, and the reduction reactor has a lining which is resistant to a hot reducing gas which is more than 50% by volume, in particular more than 90% by volume, of hydrogen gas, and further a melt reactor for producing the liquid Metal is provided, characterized in that a transport reduction reactor is provided as a reduction reactor, and the transport reduction reactor has at least one carrier gas supply line. Plant according to claim 9, characterized in that the carrier gas supply is carried out such that in the transport reduction reactor in the region of, preferably lateral, supply of the metal oxide, a directed carrier gas flow is adjustable, and the solids supply of the transport reduction reactor is designed such that the metal oxide at least partially through Introducing, in particular blowing, into the directed carrier gas stream of the transport reduction reactor, preferably in the carrier gas, is finely distributed. Plant according to claim 9 or 10, characterized in that the solid feed is carried out in a manner which makes it possible, the metal oxide, preferably controllable, by another carrier gas, the predominantly, preferably at least 90% by volume, from, optionally hot, H ₂ is to introduce into the transport reduction reactor. Installation according to one or more of claims 9 to 11, characterized in that after the transport reduction reactor, a gas-solid separation device is provided which has a lining which is compared to a hot reducing gas, the more than 50 vol%, in particular more than 90% by volume, composed of hydrogen gas, is stable. Installation according to claim 12, characterized in that the gas-solid separation device connects as a communicating vessel directly to the transport reduction reactor. Plant according to claim 12 or 13, characterized in that the melt reactor is arranged after the gas-solid separation device, and for at least partial melting and optionally Fertigreduktion the separated at least partially reduced metal oxides, wherein optionally at the melt reactor, a plasma torch and / or a Electrode for generating an electric arc is arranged. Installation according to one or more of claims 9 to 14, characterized in that the transport reduction reactor directly, preferably as a vessel communicating with the melt reactor, connects to the melt reactor.

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