CA1336359C - Method and apparatus for the direct reduction of iron - Google Patents
Method and apparatus for the direct reduction of ironInfo
- Publication number
- CA1336359C CA1336359C CA000563007A CA563007A CA1336359C CA 1336359 C CA1336359 C CA 1336359C CA 000563007 A CA000563007 A CA 000563007A CA 563007 A CA563007 A CA 563007A CA 1336359 C CA1336359 C CA 1336359C
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- Prior art keywords
- gas
- iron
- reduction
- feeder
- dri
- Prior art date
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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
- C21B13/04—Making spongy iron or liquid steel, by direct processes in retorts
-
- 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
-
- 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
- Y02P10/143—Reduction of greenhouse gas [GHG] emissions of methane [CH4]
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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)
- Catalysts (AREA)
- Carbon And Carbon Compounds (AREA)
Abstract
A process for producing reformed gas for use in the direct reduction of metal oxides comprising contacting a feeder gas at reformation temperature with DRI material which acts as a catalyst. The method for the direct reduction of metal oxides to metallized iron comprises positioning DRI material in a reduction reactor below the metal oxide material to be reduced and thereafter feeding natural gas in the presence of oxygen to the DRI
material. An apparatus is provided for carrying out the direct reduction process.
material. An apparatus is provided for carrying out the direct reduction process.
Description
~ 1 33635~
BACKGROU~D OF THE INVENTION
The present invention is drawn to a process for producing reformed gas for use in the direct reduction of meta]. oxides containing iron to a metallized iron product and a method for and apparatus for the direct reduction of the metal oxides with the reformed gas.
The direct reduction of iron oxide, in forms such as pellets or lump ore, to metallic iron in the solid state has become a commercial reality throughout the world in recent years. The combined annual capacity of direct reduction plants currently in operation or under construction is in excess of 15 million metric tons of di.rect reduced iron product, which is used primarily for feedstock in electric arc steelmaking furnaces. The world demand for adaitional direct reduced iron is projected to increase at a substantial rate for many years to satisfy a growing world need for such feedstock, as additional electric arc furnace steelmaXing plants are constructea.
Known processes for the direct reduction of iron oxide to metallic iron utilizes a reformed gas as the reducing agent. ~atural gas is used as a source for generating the reformed gas. The reformed gas for use in the direct reduction process is generated in a unit called a reformer by contacting the natural gas with an .. - 1 ~ ' 1 33635q oxygen containing material in the presence of a catalyst, usually a nickel catalyst, which activate~ the . reformation reaction of the natural gas so as to yield a reformed gas which is rich in ~2 and Co. The reformed gas which is collected from the reformer is thereafter fed to a reduction reactor containing the iron oxi.de material wherein the direct reduction reaction is carried out. Thus, direct reduction processes heretofore known require two distinct reaction zones for carrying out the process, namely, a first zone for producing a reformea gas using a nickel catalyst and a second zone for carrying out the actual direct reduction process. In these conventional processes it i8 required that the reformed gas product in the first zone be -treated prior to entering the reduction zone in order to remove CO2 and/or water vapor.
Naturally, it would be highly de~irable to provide a method for the direct reduction of iron oxide .materials to metallic iron which would eliminate the necessity of separate reaction zones and the use of nickel catalysts.
Accordingly, the present invention seeks to provide an improved method for the direct reduction of metal oxides containing iron to a metallized iron p~oduct.
~ .
_ ~ .
~ . 2 ~ 1 336~59 In particular the present invention seeks to provide a method as set forth above which is carried out in the single reaction zone of a direct reduction rea~tor.
Still further the present invention seeks to provide a method as set forth above wherein direct reduced iron (DRI) material is used as a catalyst to produce a reformed gas directly in the reaction zone of a direct reduction reactor.
Still further the present invention seeks to provide an apparatus for carrying out the method of the present invention.
Further desires and advantages of the present invention will appear hereinbelow.
SUMMARY OF THE INVENTION
In accordance with the present invention the desires and advantages are readily obtained.
The present invention is drawn to a process for producing reformed gas ~or use in the direct reduction of metal oxides containing iron to a metallized iron product and a method for and apparatus for the direct reduction of the metal oxides with the reformed gas.
According to one aspect of the invention there is provided a method for the direct reduction of metal oxide containing iron to a metallized iron product in a reduction reactor by reducing said oxide ~ 1 336359 with a reformed feeder gas which is rich in H2 and CO, wherein reformation of the feeder gas is conducted with direct reduced iron ( DRI ) which is heated to 850 to 950C and which is position in the reduction reactor upstream of said oxide, with respect to flow of said feeder gas, wherein prior to the reformation, the feeder gas consists of a mixture of natural gas and gaseous oxygen-containing material in which the volume ratio o~ oxygen to natural gas is from about 0.75:1 to 1:1, and wherein the ratio of DRI to metal oxide is from 0.25:1.00 to 0.50:1.00 by weight.
In particular the reformed feeder gas comprises H2 and CO such that the re~ormed ~eeder gas is suitable for the reduction of the metal oxide to the metallized iron product; and the mixture of natural gas and gaseous oxygen-containing material is effective to produce the reformed feeder gas by the reformation.
In a particular embodiment, the method comprises providing a reduction reactor, positioning a first layer of the DRI material in the reduction reactor, introducing a metal oxide material layer into the reactor above the DRI material, preheating the reactor to reduction temperature and thereafter feeding natural gas in the presence of an oxygen containing material to the DRI material.
In accordance with the present invention, the reformed gas is produced in the reduction zone of a direct reduction reactor wherein it immediately contacts the iron oxide material to be reduced. In accordance with the present invention, an apparatus is provided for the direct reduction of the metal oxides containing iron to be metallized iron product wherein a feeder gas is first contacted with the DRI material so as to form a reformed gas which thereafter contacts the metal oxides for the direct reduction thereof.
The method of the present invention allows for a single reaction zone of a direct reduction reactor to be employed for both the production of the reformed gas for use in the reduction process and for the actual direct reduction of the iron oxide material.
In accordance with another aspect of the invention, there is provided an apparatus for carrying out the direct reduction of a metal oxide containing iron to be metallized iron product comprising a reduction reactor de~ining a reaction zone, a feeder means for feeding a feeder gas into the reaction zone, and a flow path for gas in the reactor, such that the feeder gas contacts a direct reduced iron (DRI) and is reformed prior to the contact with the metal oxide, a first support means on which a layer of direct reduced iron is located within the reaction zone at a first location, and a second support means on which the metal oxide containing iron is located in the reaction zone at a second location close to the first location, the ratio of DRI to metal oxide being from 0.25:1.00 to 0.50:1.00 by weight, the first support means being upstream of thé second support means in the flow path.
r~
-BRIEF DESCRIPTION OF THE DRA~INGS
Fig. 1 is a schematic illustration showing a reduction reactor in accordance with the present invention.
Figs. 2a, 2b and 2c are schematic illustrations of the test equipment used in the comparative examples of the instant disclosure.
Fig. 3 is a graph comparin~ the results of direct reduction in accordance with the present invention and that of ~nown processes.
DETAILED DESCRIPTIO~
The method for the direct reduction of metal oxides containing iron to a metallized iron product comprises providing a reduction reactor, positioning a first layer of DRI material in the reduction reactor, introducing a metal oxide material layer into the reactor above the DRI material, preheating the reactor to reduction temperature and thereafter feeding natural gas in the presence of an oxygen containing material to the DRI
material.
Fig. 1 i8 a schematic illustration of an apparatus for carrying out the method of the present invention.
l 33635q 87-356 The apparatus comprises a reduction reactor 10 having a first support surface 12 for supporting direct reduced iron (DRI) which acts as a catalyst in the method of the present invention for producing reformed gas rich in S H2 and C0 from natural gas. The direct reduced iron (DRI) is a product of the direct reduction process of the present invention. The first support surface 12 is provided with a plurality of apertures 14 through which gas is fed from an annular preheating zone 16 which defines a reaction zone 18. Inlet 20 is provided for feeding a feeder gas (to be described in detail hereinafter) to the annular preheating zone 16. The reactor includes a second support element 22 positioned above the first support surface 12 so as to define a space therebetween which is occupied by the D~I
material. The second support surface 22 supports the iron oxide particles 24 which are to be reduced to metallic iron in the direct reduction process of the present invention. The second support surface 22 is provided with a plurality of orifices 26 in the same manner as first support surface 12.
In accordance with the method of the present invention a feeder gas is fed to the annular preheating zone and from there up through the DRI material wherein ~ 1 336359 the feeder gas i5 reformed to a gas rich in H2 and Co. The feeder gas consists of natura~ gas mixed with an oxygen containing material. The oxygen containing material may be air, ~0~, H20, pure oæygen or any other process gas having oxygen as a component thereof.
In accordance with the present invention, the oxygen should be present in an amount with respect to the natural gas of about 0.75:1.0 to 1.0:1Ø In accordance with the further feature of the present invention, nitrogen can be fed to the reactor during the preheating thereof or with the natural gas in oxygen mixture. The purpose of the nitrogen is to avoid reoxidation of the DRI material. In accordance with the method of the present invention, the feeder gas first contacts the DRI
material in the reduction reactor and is reformed so as to form a reformed gas which i8 rich in H2 and CO.
The DRI material should be present in an amount with respect to said iron oxide material of from about 0.25:1.0 to 0.50:1.0 in order to assure enough reformed gas for the direct reduction process. The reactor is operated under the following conditions during the gas ,reforming-direct reduction process: Temperature: 850 to 950C; Pressure: 1.1 to 1.2 BAR; GAS FLOW RATE: 5 to 20 LT/min. The reformed gas produced by contacting 1 33b359 the feeder gas with the DRI material flows up through the iron oxide particles and acts as the reducing agent for the direct reduction of the metal oxides to a metallized iron product. In order to have an effective reduction process, the reformed gas should be present in an amount of from about 800 to 1400 Nm3/ton, preferably from about 1000 to 1200 Nm3/ton with respect to the iron o~ide material.
The method and apparatus of the present invention allows for an efficient direct reduction process which is superior to processes heretofore known.
Further advantages of the present invention will be obvious from the following exemplificative examples.
In order to demonstrate the advantages of the method and apparatus of the present invention compared to prior art direct reduction processes, a three step program was conducted. Figs. 2a, 2b and 2c are schematic illustrations representing each of the three steps.
Fig. 2a represents the direct reduction processes heretofore known. In accordance with these known processes a reactor 100 defining a reaction zone 102 contains a mineral sample 104 of a metal oxide containing iron. The reaction zone is selectively fed _q via line 106 with nitrogen from reservoir 108 an~ a reducing gas mixture comprising 72~ ~, 14~ C0, 9%
C02, 5~ CH4 from reservoir 110. The reduction process was carried out under standard direct xeduction conditions. After completion of the reduction process the weight loss of the material was measured continuously by means of a thermobalance and a reduction curve generated using the following formula:
%R = initial weight - final weight x 100 initial weight The reduction curve as shown in Fig. 3 indicates that 90~ reduction was obtained for the iron oxide material employing the prior art direct reduction process.
In order to demonstrate the utility of DRI as a catalyst in the generation of a reformed gas, a reaction zone identical to that of Example 1 was employed. With reference to Fig. 2b the reaction zone contained a charge of DRI material. The reaction zone was selectively fed with nitrogen (solely for heating and cooling purposes), C02 and natural gas from reservoirs 112, 114, and 116 respectively at the following flow rates: 5 lts/min., 4 lts/min. and 6 Its/min. The ~) -~- 133635~
reformation reaction was conducted under the following conditions: 200 gr. DRI material; Temperature of 900C
with a feeder gas of 10 lts/min. (4 lts/min. CO2 and 6 lts/min. CH~). At different times during the reformation reaction exit gases were sampled in order to determine composition of same. Table 1 hereinbelow sets forth the time exposure in the reaction chamber and the reformed gas produced using DRI as a catalyst. As can be seen, the reformed gas is rich in H2 and CO.
~\
- ` ~ 3363~9 TABLE I
Exposure Reactor Reformed Gas With DRI
Time Feeder Natural . Gas H2 C0 C02 gas (mln. ) Mixture of C02 49.5 36 7,5 7,0 Natural Gas Mixture of C02 49.5 36 7.5 7,0 ~atural Gas 100 Mixture of Co2 49.5 36 7.5 7.0 Natural Gas 120 Mixture of CO2 49.5 36 7.5 7.0 Natural Gas /~
~7-356 In order to determine the effectiveness of the direct reduction process of the present invention, iron oxide was reacted in the reactor described in Fig. 1 in S the following manner. The DRI material 200 grams was positioned in the reactor and the iron oxide material 500 grams was placed on top of the DRI material. The reaction zone was preheated to the reduction temperature of 900C. Thereafter a mixture of Co2 and natural gas 40% CO2 and 60% CH4 was fed to the reaction zone at a rate of 10 lts/min. from the bottom of the reaction zone so as to insure contact with the DRI material prior to contact with the metal oxide. After completion of the reduction process weight loss was measured and a second re~uction curve generated. As can be seen from Fig. 3, the grade of reduction obtained in accordance with the process of the present invention is virtually identical to that obtained in the known reduction process of Example 1 thereby demonstrating the effectiveness of the method of the present invention.
This invention may be embodied in other forms or carried out in other ways without departing from the spirit or e~sential characteristics thereof. The 1 33~359 present embodiment is therefore to be considered as in all respects illustrative and not restrictive, the scope of the invention being indicated by the appended claims, and all changes which come within the meaning and range of equivalency are intended to be embraced therein.
BACKGROU~D OF THE INVENTION
The present invention is drawn to a process for producing reformed gas for use in the direct reduction of meta]. oxides containing iron to a metallized iron product and a method for and apparatus for the direct reduction of the metal oxides with the reformed gas.
The direct reduction of iron oxide, in forms such as pellets or lump ore, to metallic iron in the solid state has become a commercial reality throughout the world in recent years. The combined annual capacity of direct reduction plants currently in operation or under construction is in excess of 15 million metric tons of di.rect reduced iron product, which is used primarily for feedstock in electric arc steelmaking furnaces. The world demand for adaitional direct reduced iron is projected to increase at a substantial rate for many years to satisfy a growing world need for such feedstock, as additional electric arc furnace steelmaXing plants are constructea.
Known processes for the direct reduction of iron oxide to metallic iron utilizes a reformed gas as the reducing agent. ~atural gas is used as a source for generating the reformed gas. The reformed gas for use in the direct reduction process is generated in a unit called a reformer by contacting the natural gas with an .. - 1 ~ ' 1 33635q oxygen containing material in the presence of a catalyst, usually a nickel catalyst, which activate~ the . reformation reaction of the natural gas so as to yield a reformed gas which is rich in ~2 and Co. The reformed gas which is collected from the reformer is thereafter fed to a reduction reactor containing the iron oxi.de material wherein the direct reduction reaction is carried out. Thus, direct reduction processes heretofore known require two distinct reaction zones for carrying out the process, namely, a first zone for producing a reformea gas using a nickel catalyst and a second zone for carrying out the actual direct reduction process. In these conventional processes it i8 required that the reformed gas product in the first zone be -treated prior to entering the reduction zone in order to remove CO2 and/or water vapor.
Naturally, it would be highly de~irable to provide a method for the direct reduction of iron oxide .materials to metallic iron which would eliminate the necessity of separate reaction zones and the use of nickel catalysts.
Accordingly, the present invention seeks to provide an improved method for the direct reduction of metal oxides containing iron to a metallized iron p~oduct.
~ .
_ ~ .
~ . 2 ~ 1 336~59 In particular the present invention seeks to provide a method as set forth above which is carried out in the single reaction zone of a direct reduction rea~tor.
Still further the present invention seeks to provide a method as set forth above wherein direct reduced iron (DRI) material is used as a catalyst to produce a reformed gas directly in the reaction zone of a direct reduction reactor.
Still further the present invention seeks to provide an apparatus for carrying out the method of the present invention.
Further desires and advantages of the present invention will appear hereinbelow.
SUMMARY OF THE INVENTION
In accordance with the present invention the desires and advantages are readily obtained.
The present invention is drawn to a process for producing reformed gas ~or use in the direct reduction of metal oxides containing iron to a metallized iron product and a method for and apparatus for the direct reduction of the metal oxides with the reformed gas.
According to one aspect of the invention there is provided a method for the direct reduction of metal oxide containing iron to a metallized iron product in a reduction reactor by reducing said oxide ~ 1 336359 with a reformed feeder gas which is rich in H2 and CO, wherein reformation of the feeder gas is conducted with direct reduced iron ( DRI ) which is heated to 850 to 950C and which is position in the reduction reactor upstream of said oxide, with respect to flow of said feeder gas, wherein prior to the reformation, the feeder gas consists of a mixture of natural gas and gaseous oxygen-containing material in which the volume ratio o~ oxygen to natural gas is from about 0.75:1 to 1:1, and wherein the ratio of DRI to metal oxide is from 0.25:1.00 to 0.50:1.00 by weight.
In particular the reformed feeder gas comprises H2 and CO such that the re~ormed ~eeder gas is suitable for the reduction of the metal oxide to the metallized iron product; and the mixture of natural gas and gaseous oxygen-containing material is effective to produce the reformed feeder gas by the reformation.
In a particular embodiment, the method comprises providing a reduction reactor, positioning a first layer of the DRI material in the reduction reactor, introducing a metal oxide material layer into the reactor above the DRI material, preheating the reactor to reduction temperature and thereafter feeding natural gas in the presence of an oxygen containing material to the DRI material.
In accordance with the present invention, the reformed gas is produced in the reduction zone of a direct reduction reactor wherein it immediately contacts the iron oxide material to be reduced. In accordance with the present invention, an apparatus is provided for the direct reduction of the metal oxides containing iron to be metallized iron product wherein a feeder gas is first contacted with the DRI material so as to form a reformed gas which thereafter contacts the metal oxides for the direct reduction thereof.
The method of the present invention allows for a single reaction zone of a direct reduction reactor to be employed for both the production of the reformed gas for use in the reduction process and for the actual direct reduction of the iron oxide material.
In accordance with another aspect of the invention, there is provided an apparatus for carrying out the direct reduction of a metal oxide containing iron to be metallized iron product comprising a reduction reactor de~ining a reaction zone, a feeder means for feeding a feeder gas into the reaction zone, and a flow path for gas in the reactor, such that the feeder gas contacts a direct reduced iron (DRI) and is reformed prior to the contact with the metal oxide, a first support means on which a layer of direct reduced iron is located within the reaction zone at a first location, and a second support means on which the metal oxide containing iron is located in the reaction zone at a second location close to the first location, the ratio of DRI to metal oxide being from 0.25:1.00 to 0.50:1.00 by weight, the first support means being upstream of thé second support means in the flow path.
r~
-BRIEF DESCRIPTION OF THE DRA~INGS
Fig. 1 is a schematic illustration showing a reduction reactor in accordance with the present invention.
Figs. 2a, 2b and 2c are schematic illustrations of the test equipment used in the comparative examples of the instant disclosure.
Fig. 3 is a graph comparin~ the results of direct reduction in accordance with the present invention and that of ~nown processes.
DETAILED DESCRIPTIO~
The method for the direct reduction of metal oxides containing iron to a metallized iron product comprises providing a reduction reactor, positioning a first layer of DRI material in the reduction reactor, introducing a metal oxide material layer into the reactor above the DRI material, preheating the reactor to reduction temperature and thereafter feeding natural gas in the presence of an oxygen containing material to the DRI
material.
Fig. 1 i8 a schematic illustration of an apparatus for carrying out the method of the present invention.
l 33635q 87-356 The apparatus comprises a reduction reactor 10 having a first support surface 12 for supporting direct reduced iron (DRI) which acts as a catalyst in the method of the present invention for producing reformed gas rich in S H2 and C0 from natural gas. The direct reduced iron (DRI) is a product of the direct reduction process of the present invention. The first support surface 12 is provided with a plurality of apertures 14 through which gas is fed from an annular preheating zone 16 which defines a reaction zone 18. Inlet 20 is provided for feeding a feeder gas (to be described in detail hereinafter) to the annular preheating zone 16. The reactor includes a second support element 22 positioned above the first support surface 12 so as to define a space therebetween which is occupied by the D~I
material. The second support surface 22 supports the iron oxide particles 24 which are to be reduced to metallic iron in the direct reduction process of the present invention. The second support surface 22 is provided with a plurality of orifices 26 in the same manner as first support surface 12.
In accordance with the method of the present invention a feeder gas is fed to the annular preheating zone and from there up through the DRI material wherein ~ 1 336359 the feeder gas i5 reformed to a gas rich in H2 and Co. The feeder gas consists of natura~ gas mixed with an oxygen containing material. The oxygen containing material may be air, ~0~, H20, pure oæygen or any other process gas having oxygen as a component thereof.
In accordance with the present invention, the oxygen should be present in an amount with respect to the natural gas of about 0.75:1.0 to 1.0:1Ø In accordance with the further feature of the present invention, nitrogen can be fed to the reactor during the preheating thereof or with the natural gas in oxygen mixture. The purpose of the nitrogen is to avoid reoxidation of the DRI material. In accordance with the method of the present invention, the feeder gas first contacts the DRI
material in the reduction reactor and is reformed so as to form a reformed gas which i8 rich in H2 and CO.
The DRI material should be present in an amount with respect to said iron oxide material of from about 0.25:1.0 to 0.50:1.0 in order to assure enough reformed gas for the direct reduction process. The reactor is operated under the following conditions during the gas ,reforming-direct reduction process: Temperature: 850 to 950C; Pressure: 1.1 to 1.2 BAR; GAS FLOW RATE: 5 to 20 LT/min. The reformed gas produced by contacting 1 33b359 the feeder gas with the DRI material flows up through the iron oxide particles and acts as the reducing agent for the direct reduction of the metal oxides to a metallized iron product. In order to have an effective reduction process, the reformed gas should be present in an amount of from about 800 to 1400 Nm3/ton, preferably from about 1000 to 1200 Nm3/ton with respect to the iron o~ide material.
The method and apparatus of the present invention allows for an efficient direct reduction process which is superior to processes heretofore known.
Further advantages of the present invention will be obvious from the following exemplificative examples.
In order to demonstrate the advantages of the method and apparatus of the present invention compared to prior art direct reduction processes, a three step program was conducted. Figs. 2a, 2b and 2c are schematic illustrations representing each of the three steps.
Fig. 2a represents the direct reduction processes heretofore known. In accordance with these known processes a reactor 100 defining a reaction zone 102 contains a mineral sample 104 of a metal oxide containing iron. The reaction zone is selectively fed _q via line 106 with nitrogen from reservoir 108 an~ a reducing gas mixture comprising 72~ ~, 14~ C0, 9%
C02, 5~ CH4 from reservoir 110. The reduction process was carried out under standard direct xeduction conditions. After completion of the reduction process the weight loss of the material was measured continuously by means of a thermobalance and a reduction curve generated using the following formula:
%R = initial weight - final weight x 100 initial weight The reduction curve as shown in Fig. 3 indicates that 90~ reduction was obtained for the iron oxide material employing the prior art direct reduction process.
In order to demonstrate the utility of DRI as a catalyst in the generation of a reformed gas, a reaction zone identical to that of Example 1 was employed. With reference to Fig. 2b the reaction zone contained a charge of DRI material. The reaction zone was selectively fed with nitrogen (solely for heating and cooling purposes), C02 and natural gas from reservoirs 112, 114, and 116 respectively at the following flow rates: 5 lts/min., 4 lts/min. and 6 Its/min. The ~) -~- 133635~
reformation reaction was conducted under the following conditions: 200 gr. DRI material; Temperature of 900C
with a feeder gas of 10 lts/min. (4 lts/min. CO2 and 6 lts/min. CH~). At different times during the reformation reaction exit gases were sampled in order to determine composition of same. Table 1 hereinbelow sets forth the time exposure in the reaction chamber and the reformed gas produced using DRI as a catalyst. As can be seen, the reformed gas is rich in H2 and CO.
~\
- ` ~ 3363~9 TABLE I
Exposure Reactor Reformed Gas With DRI
Time Feeder Natural . Gas H2 C0 C02 gas (mln. ) Mixture of C02 49.5 36 7,5 7,0 Natural Gas Mixture of C02 49.5 36 7.5 7,0 ~atural Gas 100 Mixture of Co2 49.5 36 7.5 7.0 Natural Gas 120 Mixture of CO2 49.5 36 7.5 7.0 Natural Gas /~
~7-356 In order to determine the effectiveness of the direct reduction process of the present invention, iron oxide was reacted in the reactor described in Fig. 1 in S the following manner. The DRI material 200 grams was positioned in the reactor and the iron oxide material 500 grams was placed on top of the DRI material. The reaction zone was preheated to the reduction temperature of 900C. Thereafter a mixture of Co2 and natural gas 40% CO2 and 60% CH4 was fed to the reaction zone at a rate of 10 lts/min. from the bottom of the reaction zone so as to insure contact with the DRI material prior to contact with the metal oxide. After completion of the reduction process weight loss was measured and a second re~uction curve generated. As can be seen from Fig. 3, the grade of reduction obtained in accordance with the process of the present invention is virtually identical to that obtained in the known reduction process of Example 1 thereby demonstrating the effectiveness of the method of the present invention.
This invention may be embodied in other forms or carried out in other ways without departing from the spirit or e~sential characteristics thereof. The 1 33~359 present embodiment is therefore to be considered as in all respects illustrative and not restrictive, the scope of the invention being indicated by the appended claims, and all changes which come within the meaning and range of equivalency are intended to be embraced therein.
Claims (5)
1. A method for the direct reduction of metal oxide containing iron to a metallized iron product in a reduction reactor by reducing said oxide with a reformed feeder gas comprising H2 and CO, such that said reformed feeder gas is suitable for the reduction of said metal oxide to said metallized iron product, wherein reformation of the feeder gas is conducted with direct reduced iron (DRI) which is heated to 850 to 950°C and which is positioned in the reduction reactor upstream of said oxide, with respect to flow of said feeder gas, wherein prior to the reformation, the feeder gas consists of a mixture of natural gas and a gaseous oxygen-containing material in which the volume ratio of oxygen to natural gas is from about 0.75:1 to 1:1, said mixture being effective to produce said reformed feeder gas by said reformation, and wherein the ratio of DRI to metal oxide is from 0.25:1.00 to 0.50:1.00 by weight.
2. A method according to claim 1, wherein the oxygen-containing material comprises CO2, H2O or pure oxygen.
3. A method according to claim 1 or 2, wherein the reactor is operated at a natural gas pressure of about 1.1 to 1.2 BAR in the presence of oxygen in an amount of 16 to 20% by volume.
4. An apparatus for carrying out the direct reduction of a metal oxide containing iron to a metallized iron product comprising:
a reduction reactor defining a reaction zone, a feeder means for feeding a feeder gas into the reaction zone, and a flow path for gas in said reactor, such that said feeder gas contacts a direct reduced iron (DRI) and is reformed prior to the contact with said metal oxide, a first support means on which a layer of direct reduced iron is located within the reaction zone at a first location, and a second support means on which the metal oxide containing iron is located in said reaction zone at a second location close to the first location, the ratio of DRI to metal oxide being from 0.25:1.00 to 0.50:1.00 by weight, said first support means being upstream of said second support means in said flow path.
a reduction reactor defining a reaction zone, a feeder means for feeding a feeder gas into the reaction zone, and a flow path for gas in said reactor, such that said feeder gas contacts a direct reduced iron (DRI) and is reformed prior to the contact with said metal oxide, a first support means on which a layer of direct reduced iron is located within the reaction zone at a first location, and a second support means on which the metal oxide containing iron is located in said reaction zone at a second location close to the first location, the ratio of DRI to metal oxide being from 0.25:1.00 to 0.50:1.00 by weight, said first support means being upstream of said second support means in said flow path.
5. An apparatus according to claim 4, wherein the first support means is below the second support means.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US115,911 | 1987-11-02 | ||
| US11591187A | 1987-11-25 | 1987-11-25 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1336359C true CA1336359C (en) | 1995-07-25 |
Family
ID=22364094
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000563007A Expired - Fee Related CA1336359C (en) | 1987-11-02 | 1988-03-31 | Method and apparatus for the direct reduction of iron |
Country Status (6)
| Country | Link |
|---|---|
| AR (1) | AR246986A1 (en) |
| BR (1) | BR8804025A (en) |
| CA (1) | CA1336359C (en) |
| DE (1) | DE3811654A1 (en) |
| GB (1) | GB2211860B (en) |
| MX (1) | MX167965B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5064467A (en) * | 1987-11-02 | 1991-11-12 | C.V.G. Siderurgica Del Orinoco, C.A. | Method and apparatus for the direct reduction of iron |
| DE4041689C2 (en) * | 1990-04-20 | 1995-11-09 | Orinoco Siderurgica | Process and plant for producing liquid steel from iron oxides |
| DE4108283A1 (en) * | 1991-03-14 | 1992-09-17 | Kortec Ag | METHOD FOR PRODUCING LIQUID METAL FROM FINE-GRAIN METAL OXIDE PARTICLES, AND REDUCTION AND MELTING STOVES FOR CARRYING OUT THE METHOD |
| DE19634348A1 (en) | 1996-08-23 | 1998-02-26 | Arcmet Tech Gmbh | Melting unit with an electric arc furnace |
| DE102007032419B4 (en) * | 2007-07-10 | 2013-02-21 | Outotec Oyj | Process and plant for the reduction of iron oxide-containing solids |
Family Cites Families (19)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2711368A (en) * | 1949-12-01 | 1955-06-21 | Exxon Research Engineering Co | Process for reducing oxidic iron ore |
| DE1201377B (en) * | 1961-11-23 | 1965-09-23 | Huettenwerk Oberhausen Ag | Process and plant for the production of iron sponge from iron ore in a reduction shaft using reducing gas |
| GB1045602A (en) * | 1964-01-24 | 1966-10-12 | Armco Steel Corp | Method of reducing fine iron ore in a fluidized-solids reactor |
| US3375099A (en) * | 1964-06-30 | 1968-03-26 | Armco Steel Corp | Production of iron from pelletized iron ores |
| US3375098A (en) * | 1964-07-22 | 1968-03-26 | Armco Steel Corp | Gaseous reduction of iron ores |
| DE1433383A1 (en) * | 1964-07-28 | 1969-05-08 | Schenk Dr Ing Dr Ing E H Herma | Process for the heat treatment of iron ore, in particular iron ore pellets |
| US3764123A (en) * | 1970-06-29 | 1973-10-09 | Midland Ross Corp | Method of and apparatus for reducing iron oxide to metallic iron |
| BE791243A (en) * | 1971-12-23 | 1973-05-10 | Texaco Development Corp | PROCESS FOR PRODUCING A REDUCING GAS MIXTURE |
| US3985548A (en) * | 1972-05-30 | 1976-10-12 | Leas Brothers Development Corporation | Direct metal reduction from coal |
| US3827879A (en) * | 1973-02-22 | 1974-08-06 | Fierro Esponja | Method for the gaseous reduction of metal ores |
| US4046557A (en) * | 1975-09-08 | 1977-09-06 | Midrex Corporation | Method for producing metallic iron particles |
| US4054444A (en) * | 1975-09-22 | 1977-10-18 | Midrex Corporation | Method for controlling the carbon content of directly reduced iron |
| JPS5847449B2 (en) * | 1978-04-10 | 1983-10-22 | 株式会社神戸製鋼所 | direct iron making method |
| US4261734A (en) * | 1979-09-04 | 1981-04-14 | Hylsa, S.A. | Method of making sponge iron |
| US4253867A (en) * | 1979-10-15 | 1981-03-03 | Hylsa, S.A. | Method of using a methane-containing gas for reducing iron ore |
| US4246024A (en) * | 1979-10-31 | 1981-01-20 | Grupo Industrial Alfa, S.A. | Method for the gaseous reduction of metal ores using reducing gas produced by gasification of solid or liquid fossil fuels |
| MX156697A (en) * | 1982-05-12 | 1988-09-27 | Hylsa Sa | IMPROVED METHOD FOR THE DIRECT REDUCTION OF IRON MINERALS |
| US4528030A (en) * | 1983-05-16 | 1985-07-09 | Hylsa, S.A. | Method of reducing iron ore |
| US4556417A (en) * | 1983-05-17 | 1985-12-03 | Hylsa, S.A. | Process for the direct reduction of iron ores |
-
1988
- 1988-03-31 CA CA000563007A patent/CA1336359C/en not_active Expired - Fee Related
- 1988-04-07 DE DE3811654A patent/DE3811654A1/en active Granted
- 1988-04-12 AR AR88310543A patent/AR246986A1/en active
- 1988-04-14 GB GB8808853A patent/GB2211860B/en not_active Expired - Lifetime
- 1988-04-21 MX MX011196A patent/MX167965B/en unknown
- 1988-07-29 BR BR8804025A patent/BR8804025A/en active Search and Examination
Also Published As
| Publication number | Publication date |
|---|---|
| BR8804025A (en) | 1989-05-23 |
| GB8808853D0 (en) | 1988-05-18 |
| AR246986A1 (en) | 1994-10-31 |
| DE3811654C2 (en) | 1992-08-20 |
| DE3811654A1 (en) | 1989-05-18 |
| GB2211860A (en) | 1989-07-12 |
| MX167965B (en) | 1993-04-26 |
| GB2211860B (en) | 1991-08-21 |
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| Date | Code | Title | Description |
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| MKLA | Lapsed |