EP1266971A2 - Procédé d'opération pour four à sole tournante - Google Patents

Procédé d'opération pour four à sole tournante Download PDF

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Publication number
EP1266971A2
EP1266971A2 EP02012441A EP02012441A EP1266971A2 EP 1266971 A2 EP1266971 A2 EP 1266971A2 EP 02012441 A EP02012441 A EP 02012441A EP 02012441 A EP02012441 A EP 02012441A EP 1266971 A2 EP1266971 A2 EP 1266971A2
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EP
European Patent Office
Prior art keywords
fuel
furnace
hearth furnace
moving hearth
operation method
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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EP02012441A
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German (de)
English (en)
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EP1266971A3 (fr
Inventor
Kojiro Kobe Steel Ltd. Osaka Branch Fuji
Makoto Kobe Corporate Research Labs. Nishimura
Hidetoshi Kobe Steel Ltd. Osaka Branch Tanaka
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Kobe Steel Ltd
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Kobe Steel Ltd
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Publication of EP1266971A2 publication Critical patent/EP1266971A2/fr
Publication of EP1266971A3 publication Critical patent/EP1266971A3/fr
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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
    • C21B13/0066—Preliminary conditioning of the solid carbonaceous reductant
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B13/00—Making spongy iron or liquid steel, by direct processes
    • C21B13/10—Making spongy iron or liquid steel, by direct processes in hearth-type furnaces

Definitions

  • the present invention relates to methods for manufacturing reduced metals by reducing metal oxides by heating.
  • the present invention relates to an operation method of a moving hearth furnace which is used for manufacturing a reduced metal by reducing a metal oxide by heating.
  • a shaft-furnace method represented by Midrex method is known as a manufacturing method of reduced iron by directly reducing an iron oxide source such as an iron ore or an iron oxide by using a carbonaceous material or a reducing gas.
  • metallic iron is obtained by reducing an iron oxide by using a reducing gas which is manufactured from natural gas or the like.
  • the reducing gas reformed from natural gas or the like is used as a reducing agent, the cost of the gas significantly affects the cost of the final product, and the reduction of the cost is difficult.
  • a smelting reduction method such as a DIOS method is known as another method for obtaining reduced iron by directly reducing iron oxide.
  • this method requires complex operations and is lack of versatility with respect to the productivity and the equipment cost.
  • the inventors paid attention to the above-described circumstances and proposed a method for manufacturing reduced iron by using a rotary-hearth furnace, which is a type of moving hearth furnace, by reducing an agglomerate which includes a carbonaceous reducing agent and an iron oxide (hereinafter referred to as "iron oxide pellet including carbonaceous reducing agent” or simply as "pellet”) (for example, in Japanese Unexamined Patent Application Publication No. 11-61216).
  • the carbonaceous material which is necessary for reduction, is incorporated with pellets, and another carbonaceous material is applied to the surfaces of the pellets in order to suppress re-oxidation at the surfaces of the reduced pellets, whereby the ash content of the carbonaceous material included in the reduced pellets is reduced, thereby elevating the quality level of the reduced iron.
  • the metal oxide pellet including carbonaceous reducing agents are loaded onto the hearth of a moving hearth furnace, the pellets are heated mainly with heat of combustion of burners and the radiant heat from furnace walls, and the iron oxide is reduced by the incorporated carbonaceous material. That is, the pellets must be supplied with heat from the outside, because the reduction reaction is an endothermic reaction, when the iron oxide included in the pellets including carbonaceous reducing agent is reduced by the carbonaceous material included in the pellets. Therefore, heavy oil, natural gas, pulverized coal, and/or the like has been hitherto used as a fuel for the burners and an auxiliary fuel. However, there is a limit to the amount of production of the above fuels, and in particular, heavy oil and natural gas are comparatively expensive; therefore, reduction of the manufacturing cost has been difficult.
  • the inventors have studied to develop technologies in which metallic iron having high iron purity can be obtained efficiently in a simple process from iron oxides having high iron-contents as a matter of course and also from iron ores and the like which have relatively a low iron-content. As a result, the inventors developed a method described below and proposed the same in, for example, Japanese Unexamined Patent Application Publication No. 9-256017.
  • the method is characterized in that when metallic iron is manufactured by reducing metal oxide pellet including carbonaceous reducing agents by heating, an outer skin of the metallic iron is formed and developed by reducing an iron oxide in a solid phase, the solid-phase reduction is advanced until the inside iron oxide substantially disappears, heating continues such that slag flows to the outside of the outer skin of the metallic iron, and the metallic iron and the slag are separated from each other.
  • the high-purity metallic iron obtained by this method and the produced slag are solidified by cooling, the solidified slag is crushed, and the granulated metallic iron is separated from the slag by magnetic separation or by using a screen, or the metallic iron and the slag are melted by being heated and are separated from each other by using the difference of specific gravities.
  • combustible waste materials such as waste oil and waste plastics as fuel for blast furnaces and converters
  • the combustible waste materials are most likely to include chlorides or sulfides which form HCl or SO x as a source of air pollution. Additional facilities are required for disposing of the source of air pollution included in the exhaust gas; therefore, it has been difficult to efficiently use the combustible waste materials.
  • the sulfur concentration in the exhaust gas can be reduced by this technology, the harmful components of the exhaust gas other than sulfur (in particular, chlorine, dioxin, and the like which derive from the chlorides contained in the raw material) are not considered, and such a problem is left to be solved.
  • an object of the present invention is to provide an operation method of a moving hearth furnace, by which effective utilization of resources can be advanced and the cost can be reduced by using industrial wastes as a fuel for the moving hearth furnace for reducing metal oxides.
  • Another object of the present invention is to provide an operation method of a moving hearth furnace, by which air-pollution problems can be overcome.
  • an operation method of a moving hearth furnace in which a reduced metal is obtained by loading a metal oxide into the moving hearth furnace and reducing the metal oxide by heating, comprises the steps of supplying a fuel including combustible wastes as a heat source into the moving hearth furnace and burning the fuel.
  • the type of the fuel including combustible wastes and the way of supply of the fuel as a heat source into a moving hearth furnace may be one selected from or may be an appropriate combination of those described below.
  • the diameter of each orifice of a spray for spraying the fuel is preferably set to be not smaller than 1.1 mm
  • the temperature in the furnace is preferably set to be not lower than 150°C
  • the fuel is preferably ignited by a pilot burner which is disposed in the vicinity of a position at which the fuel is sprayed, whereby stable combustion of the fuel can be maintained.
  • the temperature in the furnace is preferably set to be not lower than 1100°C and the residence time of the fuel in the furnace is preferably set to be not shorter than three minutes, whereby a stable operation can be maintained.
  • the operation method of a moving hearth furnace preferably further comprises the step of including an alkali metal to the fuel.
  • the amount of the alkali metal to be included in the fuel is preferably controlled in accordance with the amount of S and Cl generated in the furnace during the reduction by heating.
  • the cost of fuel for reduction by heating can be significantly reduced by using effectively a fuel including combustible wastes as a fuel for the reduction by heating of a metal oxide in a moving hearth furnace.
  • Fig. 1 is an illustration showing a rotary-hearth furnace and processes of treating exhaust gas which is discharged from the rotary-hearth furnace, according to the present invention.
  • Fig. 2 is an illustration of the rotary-hearth furnace according to the present invention.
  • Fig. 3 is a sectional view along line A-A of the rotary-hearth furnace shown in Fig. 2.
  • Fig. 4 is a sectional view of the rotary-hearth furnace shown in Fig. 2 extended in the longitudinal direction.
  • the inventors have studied to overcome the above-described problems from different angles. As a result, they have found a solution of the above problems in that a reduced metal having the same quality as that of a known reduced metal can be obtained efficiently at a low cost by using a fuel including combustible wastes as a heat source which is necessary to reduce a metal oxide by heating in a moving hearth furnace.
  • the present invention will be described in detail as follows.
  • the present invention is characterized in that the cost of fuel is reduced by using a fuel including combustible wastes as a heat source, thereby effectively utilizing the wastes as secondary resources, when manufacturing a reduced metal by reducing a metal oxide by heating in a moving hearth furnace.
  • the amount of use of the heavy oil and the natural gas can be reduced, and dumping of combustible wastes or incineration costs thereof can be suppressed.
  • the wastes include industrial wastes, specially controlled industrial wastes, and domestic wastes.
  • the industrial wastes include substances regulated by "Wastes Disposal and Public Cleaning Law” and an enforcement ordinance thereof, such as burnt residuals, sludge, waste oil, waste acid, waste alkali, waste plastics, wastepaper, waste woods, waste textiles, animal and vegetable residuals, waste rubber, waste metals, waste glass and ceramics, slag, construction and demolition wastes, animal feces and urine, animal carcasses, and ash dust.
  • combustible wastes among the above industrial wastes are used as a matter of course, because since a metal oxide is reduced in the moving hearth furnace, when the fuel includes incombustible wastes, substances which have not burned remain in the furnace, and the substances are mixed in the reduced metal, whereby the purity (quality level) of the reduced metal is lowered or complex operations become necessary for selection of the reduced metal from the substances which have not burned.
  • combustible wastes such as the waste oil and waste plastics among the above-described wastes are used; one or a mixture of two or more of these combustible wastes may be used.
  • the wastes including waste oil are particularly useful. These wastes having high combustibility and large combustion energy can also serve to assist the combustion of other wastes which have relatively low combustibility.
  • the fuel including the combustible wastes is solid, the fuel is preferably crushed in a powdered state so that stable burning is maintained.
  • the fuel including combustible wastes to be used according to the present invention is most preferably liquid, a typical one being waste oil.
  • waste oil such as waste mineral oil, waste vegetable oil, and waste animal oil can be used effectively.
  • the waste oil includes, for example, sludge from oil tanks; sludge of gas oil, kerosene, gasoline, naphtha, and the like; mineral oil waste of machine oil, lubricant oil, cutting oil, and the like; oil-press residuals of vegetable oil, such as rapeseed oil, soybean oil, rice bran oil, cottonseed oil, corn oil, palm oil, and sunflower seed oil; oil wastes of the above vegetable oil used as materials for food; terpene-based plant oil wastes such as rosin; and animal oil wastes including animal fat-and-oil waste liquids of beef, pork, mutton, chicken, fish, and the like.
  • the above-described types of waste oil may be used independently. However, they are preferably used as a mixture in an appropriate proportion between several types thereof, thereby maintaining a stable combustion state.
  • a liquid fuel including combustible wastes is supplied into the furnace in methods described below:
  • the methods ⁇ 1> to ⁇ 3> may be individually used, or a combination of two or more of the methods ⁇ 1> to ⁇ 3> may be used. Preferred embodiments of the above methods ⁇ 1> to ⁇ 3> are described in more detail as follows.
  • the calorific value is generally instable.
  • the fuel can be burned efficiently when being sprayed by using a spray.
  • the diameter of orifice of the spray for spraying the fuel is preferably ⁇ 1.1 mm or more, more preferably ⁇ 2.2 mm or more, and more preferably ⁇ 3.0 mm or more, whereby clogging of the orifices can be suppressed and stable spraying can be maintained.
  • the fuel including combustible wastes sometimes includes waste textile, wastepaper, waste rubber, mineral sludge, and the like, clogging of the orifices can be suppressed by controlling the diameter of the orifices, as described above. No maximum limit is set to the value of the diameter of the orifices; it may be any value as long as the spray can maintain a spray state such that stable combustion is maintained.
  • the temperature in the furnace when the fuel including combustible wastes is sprayed into the furnace, is preferably set to 150°C or higher, and more preferably to 500°C or higher.
  • the moving hearth furnace is preferably operated such that a pilot burner disposed in the vicinity of a position at which the fuel is sprayed ignites the fuel. That is, when the fuel is sprayed into the furnace in which the temperature is set to 150°C or higher, the moisture contained in the fuel vaporizes and only combustible substances remain, whereby the fuel burns efficiently. The combustion starts smoothly with the pilot burner igniting the fuel, thereby preventing the fuel including combustible wastes from being sprayed into the furnace without being ignited. On the other hand, when the temperature in the furnace is lower than 150°C, the fuel including combustible wastes is not adequately ignited nor burned, and it is difficult to provide a stable combustion state.
  • the temperature in the furnace is set to 600°C or higher, or preferably to 1000°C or higher, the fuel including combustible wastes is self-ignited, and a stable combustion state is obtained.
  • the method of spraying the fuel including combustible wastes is not particularly specified, a method which uses compressed air or vapor as a spraying medium may be used.
  • a method which uses compressed air or vapor as a spraying medium may be used.
  • compressed air since the water content in the fuel must be kept as small as possible in order to maintain a stable combustion in the furnace, it is preferable to use compressed air.
  • the fuel including combustible wastes may be supplied by being poured onto the hearth of the moving hearth furnace, whereby the fuel can be easily supplied.
  • the position from which the fuel is poured is not particularly specified.
  • the fuel may be poured through an inlet for supplying a metal oxide into the furnace, or a supply port for the fuel may be provided in the furnace wall or ceiling.
  • a metal oxide as a raw material for manufacturing a metal and the fuel including combustible wastes may be mixed with each other so as to form agglomerate, and the agglomerated mixture may be supplied into the furnace such that the fuel is burned in the furnace.
  • the fuel can also serve as a binder and the amount of binder for forming agglomerate of the raw material can be thereby reduced.
  • a carbonaceous reducing agent which is necessary for the reduction of a metal oxide is preferably mixed with the agglomerated raw material.
  • carbonaceous reducing agent such as pulverized coal processed simply through crushing, screening, and the like after mining, crushed coke, for example, processed by heating such as dry distillation, or petroleum coke, may be used.
  • crushed coke for example, processed by heating such as dry distillation, or petroleum coke
  • blast furnace dust collected as wastes including carbon may be also used.
  • the carbon content which is not strictly specified though, is preferably 70% or more by mass, and more preferably 80% or more by mass.
  • the above agglomerated mixture includes the mixture formed in an arbitrary shape such as an lump shape, a granule shape, a briquette-shape, a pellet-shape, and a rod-shape.
  • the method of agglomeration is not particularly specified. For example, tumbling granulation or pressing may be used.
  • the temperature in the furnace is preferably set to 1100°C or higher, more preferably to 1200°C or higher, or more preferably to 1250°C or higher, and the residence time of the fuel in the furnace is preferably set to 3 minutes or longer, more preferably to 5 minutes or longer, or more preferably to 7 minutes or longer.
  • the combustion of the fuel including combustible wastes is instable, and a part of the fuel remains unburned, the part of the fuel being discharged to the outside of the system without being burned, whereby there is a risk of reduction of the utilization efficiency.
  • the residence time of the fuel in the furnace is shorter than 3 minutes, a part of the fuel may remain unburned.
  • the residence time of 3 minutes or longer does not mean that the fuel remains in the same form as when it was supplied into the furnace, but that it takes at least 3 minutes for the fuel to completely burn out after the fuel is supplied into the furnace.
  • a sulfur oxide such as SO x , or gaseous chlorine such as Cl 2 or HCl is generated from sulfur or chlorine included in the wastes and is discharged as exhaust gas.
  • the acid gas causes acid corrosion or corrosion by low melting temperature compound and also air pollution.
  • an alkali metal contained in the fuel serves to avoid the problems.
  • the alkali metal is simultaneously vaporized during combustion and is discharged as exhaust gas.
  • the alkali metal reacts with Cl in the exhaust gas and is solidified as an alkali chloride such as NaCl or KCl.
  • SO x in the exhaust gas reacts with the alkali metal and is solidified as a sulfate such as Na 2 SO 4 or K 2 SO 4 .
  • the amount of the alkali metal to be blended with the fuel is preferably controlled in accordance with the amount of S or Cl which is generated in the furnace during reduction by heating.
  • chloric gas such as Cl 2 or HCl
  • sulfur oxides such as SO x are prevented from being discharged to the outside.
  • the above-described chlorine and sulfur can be captured in the same fashion by an alkali metal component which may be contained in the agglomerate (for example, oxide-containing cores) to be used for the manufacture of a reduced metal.
  • an alkali metal component which may be contained in the agglomerate (for example, oxide-containing cores) to be used for the manufacture of a reduced metal.
  • the alkali metal contained in the fuel is released into exhaust gas more efficiently than the alkali metal contained in the agglomerate, it is more effective to control the amount of the alkali metal contained in the fuel.
  • the amount of the alkali metal to be blended and the amount of S and Cl generated in the furnace are preferably controlled so as to satisfy the following expression.
  • other fuel means additional fuel which does not include a combustible waste.
  • the examples of “other fuel” are heavy oil, pulverized coal and so on.
  • the method of adding the alkali metal to the fuel is not particularly specified, a method of adding a lubricant containing the alkali metal to the fuel may be used. By controlling the amount of the lubricant to be blended, the amount of the alkali metal can be easily controlled.
  • a casing of the bag filter disposed in the facilities for treating the exhaust gas of the moving hearth furnace is preferably heat-insulated so that the surface temperature of the bag filter is higher than the acid dew point by at least 10°C.
  • the above-described fuel may be used as a fuel for the burner disposed in the furnace, or may be used as an auxiliary fuel by being supplied through a supply port (for example, a spray) disposed in addition to the burner.
  • a supply port for example, a spray
  • the present invention is also applicable to a case in which the above-described fuel including combustible wastes is used as a mixture with a conventional fuel (for example, heavy oil).
  • the moving hearth furnace according to the present invention is not particularly specified.
  • the present invention is also applicable to a rotary-hearth furnace or a straight hearth furnace .
  • Fig. 1 shows a rotary-hearth furnace used for reduction by heating of a metal oxide and exhaust-gas treating facilities for exhaust gas discharged during the reduction by heating.
  • Numeral 5 in the drawing denotes a rotary-furnace (extension of a rotary-furnace shown in Fig. 2).
  • the exhaust gas from the rotary-hearth furnace produced during the reduction by heating of the metal oxide flows via a path 11.
  • Coarse powder dust and the like are removed from the exhaust gas in a gas-cooling tower 21.
  • the treated exhaust gas flows via a path 12 into a heat exchanger 23, and is cooled by exchanging heat with the air supplied by an air blower 22.
  • the heated air as combustion air is supplied via a path 14 to a burner which is mounted to the rotary-hearth furnace 5.
  • the surplus heated-air is discharged via a path 13 and is used as a heat source for related facilities (boiler and the like).
  • the exhaust gas cooled by exchanging heat in the heat exchanger 23 is sent to an off-gas bag filter 24 for cleaning via a path 15 and is released from a stack 26 via a path 16 and an ID fan 25.
  • a fuel such as heavy oil or natural gas is supplied to the rotary-hearth furnace 5 via a line 17, and another fuel including combustible wastes is supplied thereto via a line 10.
  • Figs. 2 to 4 are schematic illustrations for describing in detail the rotary-hearth furnace 5 shown in Fig. 1, the rotary-hearth furnace 5 including a dome structure having a donut-shaped rotary hearth.
  • Fig. 2 is a schematic perspective view.
  • Fig. 3 is a sectional view along line A-A of the rotary-hearth furnace 5 shown in Fig. 2.
  • Fig. 4 is a schematic sectional view of the rotary-hearth furnace shown in Fig. 2 extended in the rotational direction thereof for facilitating description.
  • Numeral 1 in the drawings denotes a rotary hearth and numeral 2 denotes a furnace body which covers the rotary hearth.
  • the rotary hearth 1 can be driven for rotation at a proper speed by a driving mechanism not shown.
  • a plurality of burners 3 are provided at appropriate positions of walls of the furnace body 2. Combustion heat of the burners 3 and radiation heat therefrom are transferred to an agglomerate on the rotary hearth 1, thereby reducing by heating the formed body.
  • the inside of the furnace body 2 is divided into a first zone Z 1 , a second zone Z 2 , an exhaust zone, a third zone Z 3 , and a fourth zone Z 4 by four baffle walls K 1 , K 2 , K 3 , and K 4 .
  • Loading means 4 for raw materials and raw-material additives is disposed opposing the rotary hearth 1 at the uppermost streamside in the rotational direction of the furnace body 2.
  • Discharging means 6 for a reduced metal produced by reduction by heating is provided at the lowermost streamside in the rotational direction (and directly upstream the loading means 4 in the rotational direction).
  • an agglomerate including iron oxide waste generated in a steel mill and a carbonaceous material is supplied by the loading means 4 so as to accumulate by an appropriate thickness on the rotary hearth 1 which rotates at a given speed.
  • the zones Z 1 to Z 4 are heated by the burners 3 so that the temperature therein becomes 1100°C to 1350°C.
  • the burners 3 are supplied with a fuel such as heavy oil or natural gas via the line 17 and with combustion air via the path 14.
  • the burners 3 are disposed at the sidewalls, the burners 3 may be disposed at the ceiling.
  • the inside of the rotary furnace is divided into each zone by the four baffle walls K 1 to K 4 .
  • the configuration of the furnace according to the present invention is not limited to this embodiment, and it may be modified appropriately in accordance with the size of the furnace, the targeted production capacity, the operation pattern, and the like.
  • the amount of supply of natural gas was compared between a case in which the burners 3 shown in Fig. 3 were supplied with natural gas as a fuel for manufacturing a reduced metal and another case in which a fuel including combustible wastes was supplied to sprays 7, which were provided in addition to the burners 3, and was burned in the furnace as an auxiliary fuel.
  • the burners 3 are supplied with the natural gas from the line 17 and with heated air via the path 14.
  • the sprays 7 are supplied with the fuel including combustible wastes from the line 10 and with the heated air via the path 14, and spray the fuel into the furnace with compressed air supplied via a path 18. Pilot burners 8 are provided in the vicinities of the sprays 7 for igniting the fuel.
  • a material including iron-oxide-containing dust was used as a metal oxide, which was formed as pellets having sizes of approximately 12 to 18 mm by using a disc pelletizer having a diameter of 3000 mm.
  • the carbon concentration is controlled in accordance with the requirement for the reduction of the metal oxide and the downstream melting process.
  • a mixture of waste mineral oil, waste vegetable oil, waste animal oil, and the like was used as the fuel including combustible wastes (hereinafter sometimes referred to simply as "the fuel"), and was controlled so as to have a viscosity of 15 cP at 25°C and a higher calorific value of 18.0 to 21.3 MJ/kg.
  • the composition of the fuel is shown in table 1.
  • the fuel contains moisture of 37 to 49% by mass.
  • the calorific value required of the combustion heat from the supply gas was 20.9 GJ.
  • the calorific value of 6.3 GJ required of the combustion heat from the supply gas was sufficient. That is, according to the present invention, the fuel cost can be significantly reduced.
  • a flowmeter to be appropriately used for measuring the flow rate (spray amount) of the fuel was studied. As a result, measurement by using a positive displacement meter was impossible because foreign substances included in the fuel were bitten. When an electromagnetic flowmeter was used, the fuel could continue to be sprayed because there were no moving parts in flow paths. However, electric conductivity varied according to the variation in the composition of the fuel, whereby the flow amount could not be correctly measured sometimes. A stable measurement was possible with a Coriolis-type flowmeter.
  • the temperature in the furnace is preferably controlled so as to be not lower than 150°C in order to stably ignite and burn the fuel.
  • the relationship between the temperature in the furnace and the combustion of the fuel was studied, in which the fuel was supplied by being sprayed by the sprays 7 shown in Fig. 3 and the pilot burners 8 were not used.
  • the temperature in the zone Z1 of the furnace was controlled so as to be 500°C, 700°C, and 1000°C and the combustion state of the fuel sprayed into the furnace at each temperature was monitored. As a result, combustion was difficult and the fuel was not self-ignited at a temperature of 500°C in the furnace.
  • the temperature in the furnace was 700°C, the fuel was burned although slightly instable.
  • the temperature in the furnace was 1000°C, the fuel was self-ignited. Since the calorific value of the fuel varies depending on the composition thereof, the temperature in the furnace is preferably not lower than 600°C so that the fuel including combustible wastes sprayed into the furnace is burned (self-burned).
  • the fuel was poured, without using the sprays 7, into the zone Z 1 shown in Fig. 4 of the furnace.
  • the fuel was poured into the furnace through a fuel-pouring nozzle 9 shown in Fig. 3 (although the fuel was poured into the furnace from an upper part thereof, it may be poured from a wall or the like).
  • the fuel was accumulated on the pellets immediately after it was poured, it was found to have been burned out from the hearth when viewed approximately 3 minutes after the fuel was poured.
  • No fuel content was detected in the mixed-dust agglomerates (reduced agglomerates) which were discharged approximately 12 minutes after the fuel was poured into the furnace.
  • the calorific value from the supply gas for the burners 3 could be reduced by 2.1 GJ, in comparison with the case where the fuel does not include combustible wastes.
  • the inventors confirmed that the poured fuel having a viscosity of 50 cP at 20°C was completely burned in approximately 5 minutes. In this case, the calorific value from the burners 3 could be reduced also by 2.1 GJ.
  • the amount of the alkali metal to be included in the fuel was controlled by adding a lubricant which contains the alkali metal to the fuel including combustible wastes.
  • the compositions (only S, Cl, Na, and K) of the fuel which satisfies the above expression (1) are shown in table 2, the fuel being referred to as "fuel containing alkali metal" in the table.
  • a fuel of which the content of alkali metal is less than 0.1% per chemical element is referred to as "fuel not containing alkali metal”.
  • the result of computation by using the above expression (1) is as follows.
  • Agglomerate including a metal oxide having a weight of 2000 kg was reduced by heating by using a "fuel containing an alkali metal” and another "fuel not containing alkali metal", and the volumes of generated SO x and HCl were measured at a section (A) shown in Fig. 1. The result is shown in table 3.
  • SO x and a chloric gas such as HCl included in exhaust gas which is generated during reduction by heating of a metal can be reduced when an alkali metal is contained in the fuel including combustible wastes so that the above expression (1) is satisfied.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacture And Refinement Of Metals (AREA)
  • Tunnel Furnaces (AREA)
  • Manufacture Of Iron (AREA)
  • Furnace Details (AREA)
  • Processing Of Solid Wastes (AREA)
  • Heat Treatments In General, Especially Conveying And Cooling (AREA)
EP02012441A 2001-06-11 2002-06-10 Procédé d'opération pour four à sole tournante Withdrawn EP1266971A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2001176249 2001-06-11
JP2001176249A JP2002363626A (ja) 2001-06-11 2001-06-11 移動炉床炉の操業方法

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EP1266971A2 true EP1266971A2 (fr) 2002-12-18
EP1266971A3 EP1266971A3 (fr) 2003-01-15

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US (1) US20020194961A1 (fr)
EP (1) EP1266971A3 (fr)
JP (1) JP2002363626A (fr)
AU (1) AU4588002A (fr)
CA (1) CA2390151A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1634968A1 (fr) * 2003-04-17 2006-03-15 Kabushiki Kaisha Kobe Seiko Sho Procede et appareil destines a la production de sel metallique reduit

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB0500985D0 (en) * 2005-01-18 2005-02-23 Zotefoams Plc Polyamide foams, process to make them and applications thereof
JP2012246514A (ja) * 2011-05-25 2012-12-13 Kobe Steel Ltd 還元鉄の製造方法
JP5494990B2 (ja) * 2012-02-29 2014-05-21 三菱マテリアル株式会社 乾式試金分析試料の自動溶解装置

Citations (13)

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US3998606A (en) * 1973-04-23 1976-12-21 Nippon Kokan Kabushiki Kaisha Method and apparatus for manufacturing reducing gas
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Publication number Priority date Publication date Assignee Title
EP1634968A1 (fr) * 2003-04-17 2006-03-15 Kabushiki Kaisha Kobe Seiko Sho Procede et appareil destines a la production de sel metallique reduit
EP1634968A4 (fr) * 2003-04-17 2007-12-05 Kobe Steel Ltd Procede et appareil destines a la production de sel metallique reduit
US8012236B2 (en) 2003-04-17 2011-09-06 Kabushiki Kaisha Kobe Seiko Sho Kobe Steel, Ltd. Method and apparatus for producing reduced metal

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JP2002363626A (ja) 2002-12-18

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