CA2322507A1 - Method for producing liquid pig iron and/or steel blanks - Google Patents
Method for producing liquid pig iron and/or steel blanks Download PDFInfo
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- CA2322507A1 CA2322507A1 CA002322507A CA2322507A CA2322507A1 CA 2322507 A1 CA2322507 A1 CA 2322507A1 CA 002322507 A CA002322507 A CA 002322507A CA 2322507 A CA2322507 A CA 2322507A CA 2322507 A1 CA2322507 A1 CA 2322507A1
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- Prior art keywords
- gas
- heat
- exchange fluid
- process according
- carbon carriers
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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
- C21B13/0006—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
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B13/00—Making spongy iron or liquid steel, by direct processes
- C21B13/14—Multi-stage processes processes carried out in different vessels or furnaces
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B2100/00—Handling of exhaust gases produced during the manufacture of iron or steel
- C21B2100/40—Gas purification of exhaust gases to be recirculated or used in other metallurgical processes
- C21B2100/44—Removing particles, e.g. by scrubbing, dedusting
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- 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
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- 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
- C21B2100/66—Heat exchange
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- 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
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Waste-Gas Treatment And Other Accessory Devices For Furnaces (AREA)
- Manufacture Of Iron (AREA)
Abstract
The invention relates to a method for producing liquid pig iron and/or steel blanks from materials containing iron oxide and optionally additives, preferably in the form of pieces and/or pellets. The feedstocks used are reduced to metallized iron ore in a reduction zone. The metallized iron ore is melted in a melt-down gasification zone with the addition of dried solid carbon carriers and oxygen-containing gases. A reduction gas containing CO and H2 is produced and fed into the reduction zone where it is reacted, drained off as top gas, gas washed and optionally supplied to a consumer as an export gas. Before it is washed, the top gas which is drained off from the reduction zone undergoes heat exchange with a heat exchanging fluid using all of its sensible heat. Solid carbon carriers (which are provided in order to be fed into the melt-down gasification zone) are dried with the warmed up heat exchanging fluid. The invention also relates to a system for carrying out the inventive method.
Description
Process for producing liquid pig iron and/or primary steel products The invention relates to a process for producing liquid pig iron and/or primary steel products from charge materials formed by iron-oxide-containing substances and additions if required, preferably in the form of pieces and/or pellets, the charge materials being reduced to iron sponge in a reducing zone, the iron sponge being smelted in a fusion gasifying zone supplied with dried solid carbon carriers and with oxygen-containing gases, and a CO- and HZ-containing reduction gas being generated, which gas is introduced into the reducing zone, converted there and drawn off as top gas from the reducing zone and subjected to gas scrubbing, and if required is supplied to a consumer as export gas. The invention also relates to a plant for carrying out the process according to the invention.
It is known that, for gasifying in fusion gasifiers, to improve the energy balance of the latter carbon carriers have to be dried from an average moisture content (<_ 15~). Without drying, hindrances to the transport of the carbon carriers occur, and the endothermic effect of the moisture content causes a deterioration in the energy balance and an influence on the composition of the gas generated. Without drying the carbon carriers to be gasified, the proportion of reducing constituents in the gas generated can be increased only by increasing the energy input, i.e.
increasing the amount of oxygen to be blown into the fusion gasifier.
In Austrian Patent 380 697 it is proposed to preheat coal with drawn-off blast-furnace gas. This entails increased expenditure for the construction and operation of such a plant, since additional influences during the operation of the fusion gasifier, and of the reduction furnace, have to be taken into account. What is more, part of the energy of the blast-furnace gas is used up in drying the coal and consequently reduces the efficiency of the plant.
EP 0 498 289 Al discloses a process for drying coal supplied to fusion or coal gasifiers by using excess energy produced in co-operation with a gas- and steam-turbine power station. For this purpose, excess energy is taken from an auxiliary unit and supplied to a coal drier via a fluid by heat extraction. The excess energy can in this case also be taken, inter alia, from the top gas of a reduction furnace. What is disadvantageous about this process is that the excess energy, for example of the top gas, is supplied to the actual drying medium via altogether a double heat exchange. This requires increased expenditure for setting up and operating such a plant and lessens the efficiency due to the unavoidable heat losses during heat exchange. What is also disadvantageous about the proposed process is that a drier is used for the drying of the coal. On the one hand, this requires increased expenditure on equipment and operation, on the other hand it involves heat losses of the dried and preheated coal during its transport from the drier into the gasifier.
The object of the present invention is therefore to provide a process of the type mentioned at the beginning which avoids or significantly reduces the disadvantages specified above of the prior art.
In particular, the process is to ensure effective, energy-utilizing coal drying and preheating, and at the same time require lower expenditure on both equipment and operation. The sensible heat of the dried and heated carbon carriers is to be used in this case for improving the energy balance of the fusion gasifier.
This object is achieved according to the invention by the top gas drawn off from the reducing zone undergoing heat exchange with a gaseous heat exchange fluid - before the said gas is scrubbed - and by solid carbon carriers, which are intended for being supplied into the fusion gasifying zone, being dried with the heated heat-exchange fluid.
Since the heated heat-exchange fluid is brought directly into contact with the carbon carriers to be dried, optimum energy utilization is ensured. By appropriate arrangement of the heat-exchanging and drying operation in close proximity to each other, line losses can be kept low.
It is expedient if an inert gas or inert gas mixture, which, under the conditions of the drying of the carbon carriers, behaves in a chemically inert manner with respect to the latter and to the reduction gas, is used as the heat-exchange fluid.
In an advantageous embodiment, nitrogen, in particular industrial nitrogen, as obtained from an air-separation plant, is used for this. Such industrial nitrogen is preferred, since, on account of its negligible oxygen content, higher drying temperatures can be achieved, and consequently altogether less heat-exchange fluid is required. In addition, large amounts of oxygen, and consequently an air-separation plant, are generally required in any case for the smelting reduction process. Therefore, nitrogen is readily available and inexpensive.
According to a further advantageous embodiment, cooled and cleaned process gas, which is expediently formed from CO- and HZ-containing reduction gas, for example from a partial flow of the export gas, is used as the heat-exchange fluid.
The process according to the invention is thus not restricted to the use of nitrogen or export gas as the heat-exchange fluid. In principle, every process-derived gas can be used as a heat-exchange fluid, provided that, as specified above, it behaves in an adequately inert manner. Furthermore, the gas to be used as the heat-exchange fluid must be adequately clean, in particular free from dust.
The drying of the solid carbon carriers advantageously takes place in a way known per se by a counterflow process. In this way, the heat content of the heat-exchange fluid can be utilized in a particularly energy-saving manner. Other drying processes, which operate for instance by the cross- or uniflow process, can also be used however.
Expediently used as the solid carbon carriers to be dried, or intended for use in the fusion gasifying zone, are carbon carriers in piece form, in particular coal and/or coke in piece form and/or carbon-containing pellets and/or carbon-containing briquettes.
The piece size of the carbon carriers is in this case about 8 to 50 mm. Smaller or larger piece sizes are, on the one hand, not appropriate for the requirements of the fusion gasifying zone, but in particular with smaller piece sizes there is no longer adequate gas permeability of the carbon carriers, with larger piece sizes a homogeneous drying effect of the process according to the invention is no longer ensured.
According to a preferred embodiment of the process according to the invention, the heat-exchange fluid is circulated between the heat-exchanging operation and the drying operation. Since the heat-exchange fluid emerging from the drying of the carbon carriers is laden with a certain dust burden, it is expediently subjected to gas scrubbing after the drying step.
Those amounts of heat-exchange fluid which are lost from the cycle either during the drying operation or in the gas scrubbing are replaced by a continuous supply of heat-exchange fluid into the cycle.
According to a further advantageous embodiment of the process according to the invention, the top gas is dedusted in the hot state, in particular is hot filtered, before it undergoes heat exchange with the heat-exchange fluid. Since the top gas emerging from the reducing zone is laden with a high dust burden, the known problems of clogging and plugging of the heat exchanger may result from this. These problems can be effectively obviated by hot deducting of the top gas.
The temperature of the heat-exchange fluid, after it has undergone heat exchange with the top gas, is expediently adjusted to a permissible temperature range. This temperature range is dependent on the type of coal used and is about 100 - 200 °C.
The adjusting of this temperature range advantageously takes place by supplying a partial flow of heat-exchange fluid which has not undergone heat exchange into the heated heat-exchange fluid, the temperature of the resulting mixed gas being measured and the supply of heat-exchange fluid which has not undergone heat exchange being controlled in dependence on this.
The invention also relates to a plant which is suitable for carrying out the process according to the invention.
Such a plant for producing liquid pig iron and/or primary steel products from charge materials formed by iron-oxide-containing substances, and additions if required, preferably in the form of pieces and/or pellets, having a reduction reactor for iron oxide-containing substances, a fusion gasifier, a supply line connecting the fusion gasifier to the reduction reactor for a reduction gas formed in the fusion gasifier, the supply line being provided with a gas-cleaning device, having a feed line connecting the reduction reactor to the fusion gasifier for the reduction product formed in the reduction reactor, having a top-gas removal line, leading from the reduction reactor and provided with a scrubber, having a charging bunker for solid carbon carriers, having a feed line for solid carbon carriers connecting the charging bunker to the fusion gasifier, having supply lines for oxygen-containing gases opening into the fusion gasifier and a run-off for pig iron and slag, provided on the fusion gasifier, is characterized in that in the top-gas removal line there is provided a heat exchanger and the heat exchanger is connected on the output side to the charging bunker via a line for heated heat-exchange fluid and the heat exchanger is provided on the input side with a supply line for heat s exchange fluid.
By means of this plant according to the invention it is possible for the first time to use the sensible heat of the top gas without appreciable heat losses for drying the solid carbon carriers intended for the fusion gasifier. In addition, the plant according to the invention makes it possible for the first time to do without a separate drier for the solid carbon carriers, since the drying is carried out directly in the charging bunker. This also makes it 15~ possible for the first time to use the sensible heat of the dried and heated carbon carriers in the fusion gasifier for improving the energy balance of the latter, since heat losses which occur during transport from a drier into the charging bunker likewise no longer occur.
According to a preferred embodiment of the plant according to the invention, the charging bunker is connected by means of a return line to the supply line of the heat-exchange fluid. This makes it possible to circulate the heat-exchange fluid largely without volume losses.
In an advantageous way, the return line connecting the charging bunker to the supply line has a gas-cleaning device, in particular a gas scrubber.
Since the heat-exchange fluid leaving the charging bunker has a certain dust burden and a moisture content, it is advantageous to dedust the heat-exchange fluid before entry into the heat exchanger and to expel the moisture from the cycle. This also has the effect that a blower arranged in this line is protected from the abrasive action of entrained dust.
According to a further feature of the plant according to the invention, in the top-gas removal line there is provided upstream of the heat exchanger a hot-gas filter, in order to dedust the top gas before its entry into the heat exchanger and to avoid the problems resulting from such a dust burden, such as for example plugging and blockages of the heat exchanger.
The plant according to the invention expediently has a temperature bypass line which contains a control valve and connects the line for heat-exchange fluid to undergo heat exchange to the line for heated heat-exchange fluid. In dependence on the desired final temperature of the heat-exchange fluid, the mixture of the two heat-exchange fluid flows is controlled by means of the control valve.
The process according to the invention, and the plant according to the invention, are explained in more detail below with reference to the exemplary embodiment schematically represented in Figure 1. v A reduction reactor designed as a shaft furnace 1, i.e. its reducing zone 2, is charged from above, via a supply line 3, with iron-oxide-containing charge materials in piece form, such as ore 4, if required with uncalcined additions 5. The shaft furnace 1 is in connection with a fusion gasifier 6, in which a reduction gas is generated from carbon carriers and oxygen-containing gas, is supplied via a supply line 7 to the shaft furnace 1 and flows through the latter in counterflow with respect to the charge materials 4, 5.
In the supply line 7 there is provided a gas-cleaning device 8. For temperature adjustment, the reduction gas has cooled reduction gas added to it (not shown).
Undried, solid carbon carriers 10 in piece form are fed from a storage bunker 9 into a charging bunker 11, where they are dried. The dry carbon carriers 12 are fed via a feeding means 13 into the fusion gasifier 6, or the fusion gasifying zone 14 of the latter.
The fusion gasifier 6 has supply lines 15 for oxygen-containing gases. In the fusion gasifier 6, molten pig iron 16 and molten slag 17 collect underneath the fusion gasifying zone 14 and are tapped via a run-off 18.
_ g _ The charge materials 4, 5 partly or fully reduced to iron sponge in the shaft furnace l, in the reducing zone 2 of the latter, are supplied to the fusion gasifier 6 via one or more feed lines 19, for example by means of feed screws. The upper part of the shaft furnace 1 is adjoined by a removal line 20 for the top gas produced in the reducing zone. This top gas is directed to a gas-cleaning means, designed as a scrubber 21, for the purpose of being freed from residual dust and water vapour.
The top gas cleaned in the scrubber 21, after COZ elimination if required (not shown), is available to a further consumer as export gas.
Provided upstream of the scrubber 21 in the top-gas removal line 20 is a heat exchanger 22, to which heat-exchange fluid is supplied via a supply line 23 by means of a blower 24 arranged therein. Arranged upstream of the heat exchanger 22 in the top-gas removal line 20 is a hot-gas filter 25, by which the top gas is dedusted before its entry into the heat exchanger 22.
Heated heat-exchange fluid is supplied via a line 26 to the lower part of the charging bunker 11.
The cooled heat-exchange fluid is drawn off from the charging bunker 11 via a return line 27, supplied to a gas scrubber 28, drawn off from the latter and re-introduced into the supply line 23.
From the supply line 23 there branches off a temperature bypass line 29, via which the admixing of cold heat-exchange fluid into the line 26 is controlled by means of a control valve 30 located in the said bypass line.
The invention is not restricted to the exemplary embodiment represented in Figure 1, but also covers all means known to a person skilled in the art which can be used for implementing the invention.
It is known that, for gasifying in fusion gasifiers, to improve the energy balance of the latter carbon carriers have to be dried from an average moisture content (<_ 15~). Without drying, hindrances to the transport of the carbon carriers occur, and the endothermic effect of the moisture content causes a deterioration in the energy balance and an influence on the composition of the gas generated. Without drying the carbon carriers to be gasified, the proportion of reducing constituents in the gas generated can be increased only by increasing the energy input, i.e.
increasing the amount of oxygen to be blown into the fusion gasifier.
In Austrian Patent 380 697 it is proposed to preheat coal with drawn-off blast-furnace gas. This entails increased expenditure for the construction and operation of such a plant, since additional influences during the operation of the fusion gasifier, and of the reduction furnace, have to be taken into account. What is more, part of the energy of the blast-furnace gas is used up in drying the coal and consequently reduces the efficiency of the plant.
EP 0 498 289 Al discloses a process for drying coal supplied to fusion or coal gasifiers by using excess energy produced in co-operation with a gas- and steam-turbine power station. For this purpose, excess energy is taken from an auxiliary unit and supplied to a coal drier via a fluid by heat extraction. The excess energy can in this case also be taken, inter alia, from the top gas of a reduction furnace. What is disadvantageous about this process is that the excess energy, for example of the top gas, is supplied to the actual drying medium via altogether a double heat exchange. This requires increased expenditure for setting up and operating such a plant and lessens the efficiency due to the unavoidable heat losses during heat exchange. What is also disadvantageous about the proposed process is that a drier is used for the drying of the coal. On the one hand, this requires increased expenditure on equipment and operation, on the other hand it involves heat losses of the dried and preheated coal during its transport from the drier into the gasifier.
The object of the present invention is therefore to provide a process of the type mentioned at the beginning which avoids or significantly reduces the disadvantages specified above of the prior art.
In particular, the process is to ensure effective, energy-utilizing coal drying and preheating, and at the same time require lower expenditure on both equipment and operation. The sensible heat of the dried and heated carbon carriers is to be used in this case for improving the energy balance of the fusion gasifier.
This object is achieved according to the invention by the top gas drawn off from the reducing zone undergoing heat exchange with a gaseous heat exchange fluid - before the said gas is scrubbed - and by solid carbon carriers, which are intended for being supplied into the fusion gasifying zone, being dried with the heated heat-exchange fluid.
Since the heated heat-exchange fluid is brought directly into contact with the carbon carriers to be dried, optimum energy utilization is ensured. By appropriate arrangement of the heat-exchanging and drying operation in close proximity to each other, line losses can be kept low.
It is expedient if an inert gas or inert gas mixture, which, under the conditions of the drying of the carbon carriers, behaves in a chemically inert manner with respect to the latter and to the reduction gas, is used as the heat-exchange fluid.
In an advantageous embodiment, nitrogen, in particular industrial nitrogen, as obtained from an air-separation plant, is used for this. Such industrial nitrogen is preferred, since, on account of its negligible oxygen content, higher drying temperatures can be achieved, and consequently altogether less heat-exchange fluid is required. In addition, large amounts of oxygen, and consequently an air-separation plant, are generally required in any case for the smelting reduction process. Therefore, nitrogen is readily available and inexpensive.
According to a further advantageous embodiment, cooled and cleaned process gas, which is expediently formed from CO- and HZ-containing reduction gas, for example from a partial flow of the export gas, is used as the heat-exchange fluid.
The process according to the invention is thus not restricted to the use of nitrogen or export gas as the heat-exchange fluid. In principle, every process-derived gas can be used as a heat-exchange fluid, provided that, as specified above, it behaves in an adequately inert manner. Furthermore, the gas to be used as the heat-exchange fluid must be adequately clean, in particular free from dust.
The drying of the solid carbon carriers advantageously takes place in a way known per se by a counterflow process. In this way, the heat content of the heat-exchange fluid can be utilized in a particularly energy-saving manner. Other drying processes, which operate for instance by the cross- or uniflow process, can also be used however.
Expediently used as the solid carbon carriers to be dried, or intended for use in the fusion gasifying zone, are carbon carriers in piece form, in particular coal and/or coke in piece form and/or carbon-containing pellets and/or carbon-containing briquettes.
The piece size of the carbon carriers is in this case about 8 to 50 mm. Smaller or larger piece sizes are, on the one hand, not appropriate for the requirements of the fusion gasifying zone, but in particular with smaller piece sizes there is no longer adequate gas permeability of the carbon carriers, with larger piece sizes a homogeneous drying effect of the process according to the invention is no longer ensured.
According to a preferred embodiment of the process according to the invention, the heat-exchange fluid is circulated between the heat-exchanging operation and the drying operation. Since the heat-exchange fluid emerging from the drying of the carbon carriers is laden with a certain dust burden, it is expediently subjected to gas scrubbing after the drying step.
Those amounts of heat-exchange fluid which are lost from the cycle either during the drying operation or in the gas scrubbing are replaced by a continuous supply of heat-exchange fluid into the cycle.
According to a further advantageous embodiment of the process according to the invention, the top gas is dedusted in the hot state, in particular is hot filtered, before it undergoes heat exchange with the heat-exchange fluid. Since the top gas emerging from the reducing zone is laden with a high dust burden, the known problems of clogging and plugging of the heat exchanger may result from this. These problems can be effectively obviated by hot deducting of the top gas.
The temperature of the heat-exchange fluid, after it has undergone heat exchange with the top gas, is expediently adjusted to a permissible temperature range. This temperature range is dependent on the type of coal used and is about 100 - 200 °C.
The adjusting of this temperature range advantageously takes place by supplying a partial flow of heat-exchange fluid which has not undergone heat exchange into the heated heat-exchange fluid, the temperature of the resulting mixed gas being measured and the supply of heat-exchange fluid which has not undergone heat exchange being controlled in dependence on this.
The invention also relates to a plant which is suitable for carrying out the process according to the invention.
Such a plant for producing liquid pig iron and/or primary steel products from charge materials formed by iron-oxide-containing substances, and additions if required, preferably in the form of pieces and/or pellets, having a reduction reactor for iron oxide-containing substances, a fusion gasifier, a supply line connecting the fusion gasifier to the reduction reactor for a reduction gas formed in the fusion gasifier, the supply line being provided with a gas-cleaning device, having a feed line connecting the reduction reactor to the fusion gasifier for the reduction product formed in the reduction reactor, having a top-gas removal line, leading from the reduction reactor and provided with a scrubber, having a charging bunker for solid carbon carriers, having a feed line for solid carbon carriers connecting the charging bunker to the fusion gasifier, having supply lines for oxygen-containing gases opening into the fusion gasifier and a run-off for pig iron and slag, provided on the fusion gasifier, is characterized in that in the top-gas removal line there is provided a heat exchanger and the heat exchanger is connected on the output side to the charging bunker via a line for heated heat-exchange fluid and the heat exchanger is provided on the input side with a supply line for heat s exchange fluid.
By means of this plant according to the invention it is possible for the first time to use the sensible heat of the top gas without appreciable heat losses for drying the solid carbon carriers intended for the fusion gasifier. In addition, the plant according to the invention makes it possible for the first time to do without a separate drier for the solid carbon carriers, since the drying is carried out directly in the charging bunker. This also makes it 15~ possible for the first time to use the sensible heat of the dried and heated carbon carriers in the fusion gasifier for improving the energy balance of the latter, since heat losses which occur during transport from a drier into the charging bunker likewise no longer occur.
According to a preferred embodiment of the plant according to the invention, the charging bunker is connected by means of a return line to the supply line of the heat-exchange fluid. This makes it possible to circulate the heat-exchange fluid largely without volume losses.
In an advantageous way, the return line connecting the charging bunker to the supply line has a gas-cleaning device, in particular a gas scrubber.
Since the heat-exchange fluid leaving the charging bunker has a certain dust burden and a moisture content, it is advantageous to dedust the heat-exchange fluid before entry into the heat exchanger and to expel the moisture from the cycle. This also has the effect that a blower arranged in this line is protected from the abrasive action of entrained dust.
According to a further feature of the plant according to the invention, in the top-gas removal line there is provided upstream of the heat exchanger a hot-gas filter, in order to dedust the top gas before its entry into the heat exchanger and to avoid the problems resulting from such a dust burden, such as for example plugging and blockages of the heat exchanger.
The plant according to the invention expediently has a temperature bypass line which contains a control valve and connects the line for heat-exchange fluid to undergo heat exchange to the line for heated heat-exchange fluid. In dependence on the desired final temperature of the heat-exchange fluid, the mixture of the two heat-exchange fluid flows is controlled by means of the control valve.
The process according to the invention, and the plant according to the invention, are explained in more detail below with reference to the exemplary embodiment schematically represented in Figure 1. v A reduction reactor designed as a shaft furnace 1, i.e. its reducing zone 2, is charged from above, via a supply line 3, with iron-oxide-containing charge materials in piece form, such as ore 4, if required with uncalcined additions 5. The shaft furnace 1 is in connection with a fusion gasifier 6, in which a reduction gas is generated from carbon carriers and oxygen-containing gas, is supplied via a supply line 7 to the shaft furnace 1 and flows through the latter in counterflow with respect to the charge materials 4, 5.
In the supply line 7 there is provided a gas-cleaning device 8. For temperature adjustment, the reduction gas has cooled reduction gas added to it (not shown).
Undried, solid carbon carriers 10 in piece form are fed from a storage bunker 9 into a charging bunker 11, where they are dried. The dry carbon carriers 12 are fed via a feeding means 13 into the fusion gasifier 6, or the fusion gasifying zone 14 of the latter.
The fusion gasifier 6 has supply lines 15 for oxygen-containing gases. In the fusion gasifier 6, molten pig iron 16 and molten slag 17 collect underneath the fusion gasifying zone 14 and are tapped via a run-off 18.
_ g _ The charge materials 4, 5 partly or fully reduced to iron sponge in the shaft furnace l, in the reducing zone 2 of the latter, are supplied to the fusion gasifier 6 via one or more feed lines 19, for example by means of feed screws. The upper part of the shaft furnace 1 is adjoined by a removal line 20 for the top gas produced in the reducing zone. This top gas is directed to a gas-cleaning means, designed as a scrubber 21, for the purpose of being freed from residual dust and water vapour.
The top gas cleaned in the scrubber 21, after COZ elimination if required (not shown), is available to a further consumer as export gas.
Provided upstream of the scrubber 21 in the top-gas removal line 20 is a heat exchanger 22, to which heat-exchange fluid is supplied via a supply line 23 by means of a blower 24 arranged therein. Arranged upstream of the heat exchanger 22 in the top-gas removal line 20 is a hot-gas filter 25, by which the top gas is dedusted before its entry into the heat exchanger 22.
Heated heat-exchange fluid is supplied via a line 26 to the lower part of the charging bunker 11.
The cooled heat-exchange fluid is drawn off from the charging bunker 11 via a return line 27, supplied to a gas scrubber 28, drawn off from the latter and re-introduced into the supply line 23.
From the supply line 23 there branches off a temperature bypass line 29, via which the admixing of cold heat-exchange fluid into the line 26 is controlled by means of a control valve 30 located in the said bypass line.
The invention is not restricted to the exemplary embodiment represented in Figure 1, but also covers all means known to a person skilled in the art which can be used for implementing the invention.
Claims (18)
1. Process for producing liquid pig iron and/or primary steel products from charge materials formed by iron-oxide-containing substances and additions if required, preferably in the form of pieces and/or pellets, the charge materials being reduced directly to iron sponge in a reducing zone, the iron sponge being smelted in a fusion gasifying zone supplied with dried solid, and if required liquid and/or gaseous, carbon carriers and with oxygen-containing gases, and a CO- and H2-containing reduction gas being generated, which gas is introduced into the reducing zone, converted there and drawn off as top gas from the reducing zone and subjected to gas scrubbing, and if required is supplied to a consumer as export gas, the solid carbon carriers being supplied to the fusion gasifying zone from a charging bunker, characterized in that the top gas drawn off from the reducing zone undergoes heat exchange with a gaseous heat-exchange fluid - before the said gas is scrubbed - and solid carbon carriers, which are intended for being supplied into the fusion gasifying zone, are heated and dried in the charging bunker with the heated heat-exchange fluid and the heated and dried carbon carriers being introduced into the fusion gasifying zone with their perceptible heat.
2. Process according to Claim 1, characterized in that a gas or gas mixture which, under the conditions of the drying of the carbon carriers, behaves in a chemically inert manner with respect to the latter and to the reduction gas is used as the heat-exchange fluid.
3. Process according to one of Claims 1 or 2, characterized in that nitrogen, in particular industrial nitrogen, as obtained from an air-separation plant, is used as the heat-exchange fluid.
4. Process according to one of Claims 1 or 2, characterized in that cooled and cleaned process gas is used as the heat-exchange fluid.
5. Process according to Claim 4, characterized in that the cooled and cleaned process gas is formed from a CO- and H2-containing reduction gas, for example from a partial flow of the export gas.
6. Process according to one of Claims 1 to 5, characterized in that the drying of the solid carbon carriers is a counterflow drying.
7. Process according to one of Claims 1 to 6, characterized in that carbon carriers in piece form, in particular coal and/or coke in piece form and/or carbon-containing pellets and/or carbon-containing briquettes, are used as solid carbon carriers to be dried.
8. Process according to one of Claims 1 to 7, characterized in that the heat-exchange fluid is circulated.
9. Process according to one of Claims 1 to 8, characterized in that the heat-exchange fluid emerging from the drying of the carbon carriers is subjected to gas scrubbing.
10. Process according to one of Claims 8 or 9, characterized in that volume losses of the circulated heat-exchange fluid are replaced by a continuous supply of heat-exchange fluid into the cycle.
11. Process according to one of Claims 1 to 10, characterized in that the top gas is dedusted in the hot state, in particular is hot-filtered, before it undergoes heat exchange with the heat-exchange fluid.
12. Process according to one of Claims 1 to 11, characterized in that the temperature of the heat-exchange fluid, after it has undergone heat exchange with the top gas, is adjusted to a permissible temperature range.
13. Process according to Claim 12, characterized in that the temperature of the heated heat-exchange fluid is adjusted by supplying heat-exchange fluid which has not undergone heat exchange.
14. Plant for producing liquid pig iron and/or primary steel products from charge materials formed by iron-oxide-containing substances (4), and additions (5) if required, preferably in the form of pieces and/or pellets, having a reduction reactor (1) for iron-oxide-containing substances, a fusion gasifier (6), a supply line (7) connecting the fusion gasifier (6) to the reduction reactor (1) for a reduction gas formed in the fusion gasifier (6), the supply line (7) being provided with a gas-cleaning device (8), having a feed line (19) connecting the reduction reactor (1) to the fusion gasifier (6) for the reduction product formed in the reduction reactor (1), having a top-gas removal line (20), leading from the reduction reactor (1) and provided with a scrubber (21), having a charging bunker (11) for solid carbon carriers (12), having a feeding means (13) connecting the charging bunker (11) to the fusion gasifier (6), having supply lines (15) for oxygen-containing gases opening into the fusion gasifier (6) and a run-off (18) for pig iron (16) and slag (17), provided on the fusion gasifier (6), characterized in that in the top-gas removal line (20) there is provided a heat exchanger (22) and the heat exchanger (22) is connected on the output side to the charging bunker (11) via a line (26) for heated heat-exchange fluid and the heat exchanger (22) is provided on the input side with a supply line (23) for heat-exchange fluid.
15. Plant according to Claim 14, characterized in that the charging bunker (11) is connected via a return line (27) to the supply line (23) for heat-exchange fluid.
16. Plant according to Claim 15, characterized in that a gas-cleaning device (28), in particular a gas scrubber, is provided in the return line (27) downstream of the charging bunker (11).
17. Plant according to one of Claims 14 to 16, characterized in that a hot-gas filter (25) is provided in the top-gas removal line (20) upstream of the heat exchanger (22).
18. Plant according to one of Claims 14 to 17, characterized in that the supply line (23) is connected to the line (26) leaving the heat exchanger (22) via a temperature bypass line (29) containing a control valve (30).
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AT0043698A AT406964B (en) | 1998-03-11 | 1998-03-11 | METHOD FOR THE PRODUCTION OF LIQUID PIG IRON AND / OR STEEL PRE-PRODUCTS |
| ATA436/98 | 1998-03-11 | ||
| PCT/EP1999/001248 WO1999046411A1 (en) | 1998-03-11 | 1999-02-26 | Method for producing liquid pig iron and/or steel blanks |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2322507A1 true CA2322507A1 (en) | 1999-09-16 |
Family
ID=3490568
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002322507A Abandoned CA2322507A1 (en) | 1998-03-11 | 1999-02-26 | Method for producing liquid pig iron and/or steel blanks |
Country Status (12)
| Country | Link |
|---|---|
| EP (1) | EP1062369A1 (en) |
| JP (1) | JP2002506123A (en) |
| KR (1) | KR20010041710A (en) |
| CN (1) | CN1292830A (en) |
| AT (1) | AT406964B (en) |
| AU (1) | AU3254199A (en) |
| BR (1) | BR9908629A (en) |
| CA (1) | CA2322507A1 (en) |
| PL (1) | PL342950A1 (en) |
| TW (1) | TW490489B (en) |
| WO (1) | WO1999046411A1 (en) |
| ZA (1) | ZA991939B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102006048600B4 (en) * | 2006-10-13 | 2012-03-29 | Siemens Vai Metals Technologies Gmbh | Method and device for producing molten material |
| AT506640B1 (en) | 2008-03-17 | 2010-07-15 | Siemens Vai Metals Tech Gmbh | METHOD AND DEVICE FOR PRODUCING LIQUID RAW IRONS OR LIQUID STEEL PREPARED PRODUCTS |
| CN111218535A (en) * | 2020-03-15 | 2020-06-02 | 苏亚杰 | Method for producing direct reduced iron by heating circulating reducing gas in gas production of molten iron bath coal |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1800856A (en) * | 1926-04-07 | 1931-04-14 | Bradley Linn | Treating iron ore |
| DE1167368B (en) * | 1955-02-14 | 1964-04-09 | Demag Elektrometallurgie Gmbh | Operation of a low shaft furnace for refining ores |
| DE2657249C3 (en) * | 1976-12-17 | 1980-09-04 | Didier Engineering Gmbh, 4300 Essen | Process for the further use of raw furnace gas |
| AT380697B (en) * | 1984-11-07 | 1986-06-25 | Voest Alpine Ag | METHOD FOR MELTING AT LEAST PARTLY REDUCED IRON ORE AND DEVICE FOR CARRYING OUT THIS METHOD |
| JPH0689391B2 (en) * | 1986-03-31 | 1994-11-09 | 株式会社神戸製鋼所 | Fluidized bed reduction method for iron ore |
| US5529599A (en) * | 1995-01-20 | 1996-06-25 | Calderon; Albert | Method for co-producing fuel and iron |
-
1998
- 1998-03-11 AT AT0043698A patent/AT406964B/en not_active IP Right Cessation
-
1999
- 1999-02-26 WO PCT/EP1999/001248 patent/WO1999046411A1/en not_active Application Discontinuation
- 1999-02-26 CN CN99803844XA patent/CN1292830A/en active Pending
- 1999-02-26 PL PL99342950A patent/PL342950A1/en unknown
- 1999-02-26 CA CA002322507A patent/CA2322507A1/en not_active Abandoned
- 1999-02-26 KR KR1020007009933A patent/KR20010041710A/en not_active Application Discontinuation
- 1999-02-26 BR BR9908629-8A patent/BR9908629A/en not_active Application Discontinuation
- 1999-02-26 AU AU32541/99A patent/AU3254199A/en not_active Abandoned
- 1999-02-26 EP EP99939141A patent/EP1062369A1/en not_active Withdrawn
- 1999-02-26 JP JP2000535777A patent/JP2002506123A/en not_active Withdrawn
- 1999-03-05 TW TW088103394A patent/TW490489B/en active
- 1999-03-10 ZA ZA9901939A patent/ZA991939B/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| WO1999046411A1 (en) | 1999-09-16 |
| PL342950A1 (en) | 2001-07-16 |
| ATA43698A (en) | 2000-03-15 |
| TW490489B (en) | 2002-06-11 |
| EP1062369A1 (en) | 2000-12-27 |
| BR9908629A (en) | 2000-12-05 |
| AU3254199A (en) | 1999-09-27 |
| JP2002506123A (en) | 2002-02-26 |
| AT406964B (en) | 2000-11-27 |
| CN1292830A (en) | 2001-04-25 |
| KR20010041710A (en) | 2001-05-25 |
| ZA991939B (en) | 1999-09-27 |
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