EP2641981A2

EP2641981A2 - Apparatus for manufacturing molten iron and method for manufacturing molten iron using same

Info

Publication number: EP2641981A2
Application number: EP11842354.0A
Authority: EP
Inventors: Myoung-Kyun Shin; Sang-Hoon Joo; Dong-Jin Kim; Jin-Tae Kim
Original assignee: Posco Co Ltd
Current assignee: Posco Holdings Inc
Priority date: 2010-11-19
Filing date: 2011-11-18
Publication date: 2013-09-25
Anticipated expiration: 2031-11-18
Also published as: KR101187851B1; EP2641981B1; CN104694687A; WO2012067462A3; CN103221555B; CN103221555A; KR20120054262A; WO2012067462A2; EP2641981A4

Abstract

Provided are an apparatus and method for manufacturing molten iron. The apparatus for manufacturing molten iron, according to the present invention, comprises: a multi-stage fluid bed furnace for converting fine iron ores into reduced fine iron through reduction; at least one high-temperature compacting unit for preparing a high-temperature compacted iron by compressing the reduced fine iron; at least one crushing unit for crushing the high-temperature compacted iron to have a certain particle size; a first conveying unit for conveying the crushed high-temperature compacted iron; and a melting furnace for melting the conveyed high-temperature compacted iron by combusting fine or lump coal, and for supplying a reducing gas, which is generated in the furnace, to a fluidized reduction furnace. In addition, the apparatus further comprises at least one compacted iron storing unit for storing some of the compacted iron which has been crushed. According to the present invention, molten iron can be manufactured stably and efficiently.

Description

Technical Field

The present invention relates to an apparatus for manufacturing molten iron and, more particularly, to an apparatus for manufacturing molten iron which is capable of performing a molten iron work stably and efficiently by using a high-temperature compacted iron storage tank.

Background Art

In an apparatus for manufacturing molten iron which includes a multi-stage fluidized furnace and a multi-stage smelting furnace and directly uses fine or lump coal and fine iron-containing ores, if reducing gas is not sufficiently supplied from the smelting furnace to the multi-stage fluidized furnace, the formation of a fluidized bed is impossible, thereby making impossible a work itself.
Accordingly, high-temperature compacted iron manufactured by the reduction and compacting of reduced fine iron in the multi-stage fluidized furnace is not supplied to the smelting furnace.
The above condition is generated when a sufficient amount of reducing gas for the multi-stage fluidized furnace is not supplied from the smelting furnace, that is, when a work is started or stopped, and is also generated when the amount of reducing gas generated is reduced due to a reduction of the smelting furnace attributable to smelting furnace work and equipment obstacles.
Furthermore, the stop of the high-temperature reduced iron supplied to the smelting furnace is also generated when equipment for the multi-stage fluidized furnace or a high-temperature compacting apparatus fails.
If the supply of the high-temperature compacted iron to the smelting furnace is stopped, amount of heat necessary to melt the reduced iron in the smelting furnace remains.
Accordingly, the smelting furnace is overheated, and a smelting furnace work must be stopped. In order to prevent the problems, an additional iron source must be directly supplied to the smelting furnace. The additional iron source must be lump reduced iron because it has to be directly supplied to the smelting furnace. Accordingly, lump reduced iron is externally supplied in a conventional apparatus for manufacturing molten iron that directly uses fine or lump coal and ores containing fine iron ores.
As described above, the externally supplied lump reduced iron is more expensive than high-temperature reduced iron manufactured through a fluidized furnace, and it also increases a work cost for the apparatus for manufacturing molten iron. Furthermore, since the externally supplied lump reduced iron must be used in a room temperature state, amount of heat for a temperature rise in the externally supplied lump reduced iron is greater than that in the high-temperature reduced iron, thereby increasing the amount of coal necessary within the smelting furnace. As a result, a molten iron yield versus a design capacity is increased, and thus the productivity of the conventional apparatus for manufacturing molten iron that directly uses fine or lump coal and fine iron-containing ores is deteriorated.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.

DETAILED DESCRIPTION

Technical Problem

The present invention has been made in an effort to provide an apparatus for manufacturing molten iron and a method for manufacturing thereof having an advantage of providing means for increasing the stability and efficiency of a molten iron manufacturing process by manufacturing excess high-temperature compacted iron when a normal work is performed, storing the excess high-temperature compacted iron in a compacted iron storage tank, and charging the stored compacted iron into a multi-stage smelting furnace when an abnormal work is performed in an apparatus for manufacturing molten iron using a multi-stage fluidized furnace and the multi-stage smelting furnace.

Technical Solution

An exemplary embodiment of the present invention provides an apparatus for manufacturing molten iron, including a multi-stage fluidized furnace for converting fine iron ores into reduced fine iron by reducing fine iron ores, at least one compacted iron manufacturing device for manufacturing high-temperature compacted iron by compressing the reduced fine iron, at least one crushing device for crushing the high-temperature compacted iron at a specific granularity, a first conveyance device for conveying the crushed high-temperature compacted iron, and a smelting furnace for melting the conveyed high-temperature compacted iron by combusting fine or lump coal and supplying reducing gas generated within the smelting furnace to the multi-stage fluidized furnace.
The apparatus for manufacturing molten iron in accordance with an exemplary embodiment of the present invention further includes at least one compacted iron storage tank for storing some of the crushed high-temperature compacted iron.
The apparatus for manufacturing molten iron in accordance with an exemplary embodiment of the present invention further includes a second conveyance device for conveying the high-temperature compacted iron to the compacted iron storage tank.
Furthermore, 2-direction suits are disposed under the at least one crushing device.
The first outlets of the 2-direction suits supply the crushed high-temperature compacted iron to the first conveyance device, and the second outlets of the 2-direction suits supply the crushed high-temperature compacted iron to the second conveyance device.
A nitrogen supply pipe is disposed at the bottom of the compacted iron storage tank.
Furthermore, gas discharge pipes are disposed at the top of the compacted iron storage tank.
The gas discharge pipes are equipped with respective pressure control valves and configured to maintain pressure within the compacted iron storage tank higher than atmospheric pressure.
The compacted iron storage tank includes a level system for detecting an amount of compacted iron charged into the compacted iron storage tank.
The apparatus for manufacturing molten iron further includes a third conveyance device, wherein discharge devices are provided under the compacted iron storage tank and configured to supply the compacted iron to the third conveyance device, and the third conveyance device conveys the compacted iron to the first conveyance device.
The apparatus for manufacturing molten iron further includes a carbon dioxide removal device for ramifying some of exhaust gas discharged from the multi-stage fluidized furnace, removing carbon dioxide from the ramified exhaust gas, adding the exhaust gas to the reducing gas supplied from the smelting furnace, and supplying the added reducing gas to the multi-stage fluidized furnace.
The apparatus for manufacturing molten iron further includes a gas circulation cooling device for controlling temperature of reducing gas supplied to the multi-stage fluidized furnace by ramifying some of reducing gas generated from the smelting furnace, cooling the ramified reducing gas, and circulating the reducing gas supplied from the smelting furnace again.
Another exemplary embodiment of the present invention provides a method of manufacturing molten iron, including reducing fine iron ores into reduced fine iron by using the multi-stage fluidized furnace, manufacturing high-temperature compacted iron by compressing the reduced fine iron using the compacted iron manufacturing device, crushing the high-temperature compacted iron by using a crushing device, conveying the crushed compacted iron to the charging device, and charging the compacted iron from the charging device into the smelting furnace and melting the charged compacted iron by combusting fine or lump coal.
The method of manufacturing molten iron in accordance with an exemplary embodiment of the present invention further includes the step of conveying some of the crushed compacted iron to the compacted iron storage tank.
The method of manufacturing molten iron further includes the step of distributing the crushed compacted iron to the charging device or the compacted iron storage tank by using the 2-direction suits.
Furthermore, if the high-temperature compacted iron necessary for the smelting furnace is able to be manufactured through the multi-stage fluidized furnace, the compacted iron manufacturing device, and the crushing device, excess high-temperature compacted iron exceeding an amount of the high-temperature compacted iron necessary for the smelting furnace is manufactured and
The excess high-temperature compacted iron is intermittently conveyed to and stored in the compacted iron storage tank by way of an action of the 2-direction suits.
Furthermore, if the high-temperature compacted iron necessary for the smelting furnace is unable to be manufactured through the multi-stage fluidized furnace, the compacted iron manufacturing device, and the crushing device, the compacted iron stored in the compacted iron storage tank is continuously supplied to the smelting furnace via a conveyance device.
If a ratio of a yield of high-temperature compacted iron manufactured by the multi-stage fluidized furnace, the compacted iron manufacturing device, and the crushing device and demand quantity of high-temperature compacted iron necessary for the smelting furnace is defined by an excess rate as below,
The excess rate = (yield of the high-temperature compacted iron)/(demand quantity of the high-temperature compacted iron) × 100,
The excess rate is 110% to 120%.
The time that the high-temperature compacted iron stay in the compacted iron storage tank is 6 hours to 12 hours.

Advantageous Effects

In accordance with the apparatus for manufacturing molten iron according to an exemplary embodiment of the present invention, by supplying means for efficiently supplying high-temperature reduced iron to the smelting furnace independently from means for reducing, compacting, and charging fine iron ores in the multi-stage fluidized furnace, the manufacturing of molten iron in the smelting furnace can be efficiently performed even when an initial work is performed or the operation of the multi-stage fluidized furnace is stopped due to the occurrence of an equipment obstacle. Accordingly, the productivity of a molten iron manufacturing device that directly uses fine or lump coal and ores containing fine iron can be improved.

Brief Description of the Drawings

FIG. 1 is a diagram schematically showing the construction of an apparatus for manufacturing molten iron using a compacted iron storage tank capable of storing excess high-temperature compacted iron in accordance with an exemplary embodiment of the present invention.

Best Mode

The merits and characteristics of the present invention and the methods for achieving the merits and characteristics thereof will become more apparent from the following embodiments taken in conjunction with the accompanying drawing. However, the present invention is not limited to the disclosed embodiments, but may be implemented in various ways. The embodiments are provided to complete the disclosure of the present invention and to enable a person having ordinary skill in the art to understand the scope of the present invention. The present invention is defined by the category of the claims. The same reference numbers will be used to refer to the same or similar parts throughout the drawing.
Hereinafter, an apparatus for manufacturing molten iron in accordance with an exemplary embodiment of the present invention is described below with reference to the drawing. For reference, in describing the present invention, a detailed description of known functions or constructions related to the present invention will be omitted if it is deemed that they would make the gist of the present invention unnecessarily vague.
FIG. 1 is a diagram schematically showing the construction of an apparatus for manufacturing molten iron using a compacted iron storage tank 600 capable of storing excess high-temperature compacted iron in accordance with an exemplary embodiment of the present invention.
Referring to FIG. 1, fine iron ores are reduced to reduced fine iron by a multi-stage fluidized furnace 100, high-temperature compacted iron is fabricated by compressing the reduced fine iron, and the high-temperature compacted iron is crushed to a specific granularity.
The crushed high-temperature compacted iron is supplied to a first conveyance device 400 by using 2-direction suits 700 in order convey the crushed high-temperature compacted iron to a charging device, and excess compacted iron is supplied to a second conveyance device 430 that is additionally provided so that the excess compacted iron is stored in a compacted iron charging tank. Accordingly, when a work is initiated or stopped, when a work obstacle is generated, and/or and when an equipment obstacle is generated, the stored compacted iron is supplied to a smelting furnace 500, thereby being capable of manufacturing stable molten iron.
Referring to FIG. 1, the apparatus for manufacturing molten iron in accordance with an exemplary embodiment of the present invention includes a multi-stage fluidized reduction furnace for converting fine iron ores into reduced fine iron by reducing the fine iron ores, at least one high-temperature compacting apparatus for fabricating high-temperature compacted iron by compressing the reduced fine iron, at least one crushing device 300 for crushing the high-temperature compacted iron at a specific granularity, the first conveyance device 400 for conveying the crushed high-temperature compacted iron, and the smelting furnace 500 for melting the conveyed high-temperature compacted iron by combusting fine or lump coal and supplying reducing gas generated within the smelting furnace to the multi-stage fluidized furnace.
FIG. 1 illustrates a three-stage fluidized furnace 100, but this is only illustrative. The number of fluidized furnaces 100 can be three or more.
If the multi-stage fluidized furnace 100 has three stages, the first stage fluidized furnace 100 preheats fine iron ores, the second stage fluidized furnace 100 preliminarily reduces the preheated fine iron ores, and the third stage fluidized furnace 100 finally reduces the fine iron ores.
Secondary materials, such as limestone and dolomite, and an additive can also be charged into the multi-stage fluidized furnace 100 in order to prevent a phenomenon in which the fine iron ores are adhered to the inside of the multi-stage fluidized furnace 100 and prevent the reduced fine iron from being broken within the smelting furnace 500.
In order to compact the reduced fine iron ores before entering the reduced fine iron ores to the smelting furnace 500, lump reduced fine iron is manufactured using a compacted iron manufacturing device 200. The compacted iron manufacturing device 200 manufactures compacted iron by compressing the reduced fine iron ores charged therein through a pair of rolls.
The high-temperature compacted iron manufactured by the compacted iron manufacturing device 200 is crushed to a proper granularity by the crushing device 300 disposed under the compacted iron manufacturing device 200 before the high-temperature compacted iron is charged into the smelting furnace 500.
The crushed compacted iron is supplied to the first conveyance device 400 through the first outlets of the 2-direction suits 700 disposed under the crushing device 300.
The high-temperature compacted iron supplied to the first conveyance device 400 is conveyed to a charging device in order to be charged into the smelting furnace 500 and is continuously charged from the charging device to the smelting furnace 500. The smelting furnace 500 manufactures molten iron by melting the high-temperature compacted iron through the combustion of fine coal or compacted lump coal.
The smelting furnace 500 melts the compacted iron by combusting fine or lump coal using oxygen. At this time, reducing gas is generated. The smelting furnace 500 supplies the generated reducing gas to the multi-stage fluidized furnace 100 connected to the smelting furnace 500, so that reducing gas for reducing reduced fine iron is supplied to the multi-stage fluidized furnace 100.
The high-temperature compacted iron is supplied to the second conveyance device 430 disposed under the 2-direction suits 700 through the second outlets of the 2-direction suits 700. The high-temperature compacted iron is conveyed to and stored in the compacted iron storage tank 600 through the second conveyance device 430.
Mores particularly, the 2-direction suits 700 are disposed under the at least one crushing device 300. The first outlets of the 2-direction suits 700 supply the crushed high-temperature compacted iron to the first conveyance device 400, and the second outlets of the 2-direction suits 700 supply the crushed high-temperature compacted iron to the second conveyance device 430.
Valves are provided in the respective outlets of the 2-direction suits 700 so that the high-temperature compacted iron can be selectively supplied to the first conveyance device 400 or the second conveyance device 430.
Furthermore, a nitrogen supply pipe 610 is disposed at the lower part of the compacted iron storage tank 600, and gas discharge pipes 630 are disposed at the top of the compacted iron storage tank 600.
The gas discharge pipes 630 includes respective pressure control valves 635 for maintaining pressure within the compacted iron storage tank 600 higher than atmospheric pressure.
That is, the nitrogen supply pipe 610 disposed at the lower part of the compacted iron storage tank 600 supplies nitrogen, and the gas discharge pipes 630 disposed at the top of the compacted iron storage tank 600 discharges gas. The pressure control valves 635 included in the gas discharge pipes 630 maintain pressure within the compacted iron storage tank 600 higher than atmospheric pressure so that the inflow of air from the outside can be minimized.
The compacted iron storage tank 600 further includes a level system for detecting the amount of compacted iron charged therein. The level system continuously measures the height of a high-temperature compacted iron layer formed within the compacted iron storage tank 600. Accordingly, compacted iron exceeding the capacity of the compacted iron storage tank 600 can be prevented from being supplied to the compacted iron storage tank 600.
Furthermore, the level system can detect the amount of high-temperature compacted iron stored in the compacted iron storage tank 600.
The apparatus for manufacturing molten iron further includes a third conveyance device 450. Discharge apparatuses 660 are disposed at the bottom of the compacted iron storage tank 600 and configured to supply compacted iron to the third conveyance device 450. The third conveyance device 450 conveys the compacted iron to the first conveyance device 400.
The apparatus for manufacturing molten iron in accordance with an exemplary embodiment of the present invention can further include an exhaust gas reforming apparatus 800 for cooling gas discharged from the multi-stage fluidized furnace 100 via a water collector, ramifying some of the discharged gas, removing carbon dioxide from the ramified gas by compressing the ramified gas, mixing the ramified gas with high-temperature reducing gas discharged from the smelting furnace 500, and additionally supplying the mixed reducing gas to the multi-stage fluidized furnace 100.
Furthermore, in order to thermally decompose tar generated from fine coal or lump coal used in the smelting furnace 500, it is necessary to maintain temperature of high-temperature reducing gas discharged from the smelting furnace at 500 1,000°C or higher and to lower temperature of the high-temperature reducing gas to 700°C to 800°C necessary for the multi-stage fluidized furnace 100.
The temperature of the high-temperature reducing gas can be primarily cooled by mixing room-temperature carbon dioxide removal gas supplied from the exhaust gas reforming apparatus 800 with high-temperature reducing gas discharged from the smelting furnace 500.
The apparatus for manufacturing molten iron in accordance with an exemplary embodiment of the present invention can further include a gas circulation cooling device 900 for ramifying some of the high-temperature reducing gas mixed with the carbon dioxide removal gas, cooling the ramified reducing gas via the water collector, compressing the cooled reducing gas, and mixing the compressed reducing gas with the high-temperature reducing gas so that temperature of the mixed reducing gas is additionally cooled up to temperature of the reducing gas supplied to the multi-stage fluidized furnace 100.
A method of manufacturing molten iron in accordance with another exemplary embodiment of the present invention includes the steps of reducing fine iron ores into reduced fine iron by using the multi-stage fluidized furnace 100, manufacturing high-temperature compacted iron by compressing the reduced fine iron by using the compacted iron manufacturing device 200, crushing the high-temperature compacted iron by using the crushing device 300, conveying the crushed compacted iron to the charging device, charging the compacted iron from the charging device into the smelting furnace 500, and melting the charged compacted iron by combusting fine or lump coal.
The method of manufacturing molten iron further includes the step of conveying some of the crushed compacted iron to the compacted iron storage tank 600.
The method of manufacturing molten iron further includes the step of distributing the crushed compacted iron to the charging device or the compacted iron storage tank 600 by using the 2-direction suits 700.
If molten iron is normally continuously manufactured, that is, if high-temperature compacted iron necessary for the smelting furnace 500 can be manufactured through the multi-stage fluidized furnace 100, the compacted iron manufacturing device, and the crushing device 300, excess high-temperature compacted iron that exceeds the amount of the high-temperature compacted iron necessary for the smelting furnace 500 is manufactured. The excess high-temperature compacted iron intermittently discharges the high-temperature compacted iron from the crushing device 300 to the conveyance device by way of an action of the 2-direction suits 700, so the high-temperature compacted iron can be conveyed to and stored in the compacted iron storage tank 600.
In contrast, in the method of manufacturing molten iron, if molten iron is not normally manufactured, that is, if high-temperature compacted iron necessary for the smelting furnace 500 may not be manufactured through the multi-stage fluidized furnace 100, the compacted iron manufacturing device, and the crushing device 300, compacted iron stored in the compacted iron storage tank 600 is discharged to the third conveyance device 450 via the discharge devices 660 and the third conveyance device 450 conveys the discharged compacted iron to the first conveyance device 400. Accordingly, high-temperature compacted iron necessary for the smelting furnace 500 can be continuously supplied.
In order to achieve the above work, a yield of high-temperature compacted iron manufactured through the multi-stage fluidized furnace 100, the compacted iron manufacturing device 200, and the crushing device 300 must exceed demand quantity of high-temperature compacted iron necessary for the smelting furnace 500.
Assuming that a ratio of the yield of high-temperature compacted iron manufactured by the multi-stage fluidized furnace 100, the compacted iron manufacturing device 200, and the crushing device 300 and the demand quantity of the high-temperature compacted iron necessary for the smelting furnace 500 is defined by an equipment capacity excess rate as below,
Equipment capacity excess rate = (yield of high-temperature compacted iron)/(demand quantity of high-temperature compacted iron) × 100,
The equipment capacity excess rate can be 110% to 120%.
The range of the equipment capacity excess rate is based on that a ratio of the time during which an abnormal condition occurs in the entire operation time is about 80% to 90% in an apparatus for manufacturing molten iron that directly uses fine or lump coal and fine iron-containing ores.
Meanwhile, the reducing gas necessary for the multi-stage fluidized furnace 100 in order to manufacture the high-temperature compacted iron can be additionally supplied through a carbon dioxide removal device.
The time that the high-temperature compacted iron is taken to stay in the compacted iron storage tank 600 can be 6 hours to 12 hours.
Meanwhile, during a normal work, high-temperature compacted iron may be stored in the compacted iron storage tank 600 excessively long. In this case, the high-temperature compacted iron can be cooled and erupted. As a result, in an abnormal condition, the constellation of the high-temperature compacted iron supplied to the smelting furnace 500 can be deteriorated.
In order to prevent this condition from occurring, high-temperature compacted iron stored at the lower part of the high-temperature compacted iron storage tank 600 may be partially discharged through the discharge devices 660, and the discharged high-temperature compacted iron may be periodically replaced with new high-temperature compacted iron manufactured and discharged through the multi-stage fluidized furnace 100, the compacted iron manufacturing device 200, and the crushing device 300.
The time that the high-temperature compacted iron is taken to stay in the compacted iron storage tank 600 is regularly maintained through a series of the replacement processes, and the stay time may be 6 hours to 12 hours.
If the time is less than 6 hours, work and equipment expenses are inefficient because a large amount of high-temperature reduced iron must be supplied to the compacted iron storage tank 600 for the replacement and at the same time the amount of stored compacted iron corresponding to the large amount of high-temperature reduced iron must be discharged from the compacted iron storage tank 600.
In contrast, if the time is higher than 12 hours, the cooling and eruption of the high-temperature compacted iron become worse.
While some exemplary embodiments of the present invention have been described with reference to the accompanying drawing, those skilled in the art to which the present invention pertains will understand that the present invention may be implemented in other various forms without departing from the technical spirit or essential characteristics of the present invention.
Accordingly, the aforementioned embodiments should not be construed as being limitative, but should be construed as being only illustrative from all aspects. The scope of the present invention is defined by the appended claims rather than the detailed description. It should be understood that all modifications or variations derived from the meanings and scope of the present invention and equivalents thereof are included in the scope of the appended claims.
While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

An apparatus for manufacturing molten iron, comprising:
a multi-stage fluidized furnace for converting fine iron ores into reduced fine iron by reducing fine iron ores;

at least one compacted iron manufacturing device for manufacturing high-temperature compacted iron by compressing the reduced fine iron;

at least one crushing device for crushing the high-temperature compacted iron at a specific granularity;

a first conveyance device for conveying the crushed high-temperature compacted iron; and

a smelting furnace for melting the conveyed high-temperature compacted iron by combusting fine or lump coal and supplying reducing gas generated within the smelting furnace to the multi-stage fluidized furnace.
The apparatus of claim 1, further comprising at least one compacted iron storage tank for storing some of the crushed high-temperature compacted iron.
The apparatus of claim 2, further comprising a second conveyance device for conveying the high-temperature compacted iron to the compacted iron storage tank.
The apparatus of claim 3, wherein:
2-direction suits are disposed under the at least one crushing device, first outlets of the 2-direction suits supply the crushed high-temperature compacted iron to the first conveyance device, and

second outlets of the 2-direction suits supply the crushed high-temperature compacted iron to the second conveyance device.
The apparatus of claim 2, wherein a nitrogen supply pipe is disposed at a bottom of the compacted iron storage tank.
The apparatus of claim 2, wherein gas discharge pipes are disposed at a top of the compacted iron storage tank.
The apparatus of claim 6, wherein the gas discharge pipes are equipped with respective pressure control valves and configured to maintain pressure within the compacted iron storage tank higher than atmospheric pressure.
The apparatus of any one of claims 5 to 7, wherein the compacted iron storage tank comprises a level system for detecting an amount of compacted iron charged into the compacted iron storage tank.
The apparatus of claim 3 or 8, further comprising a third conveyance device, wherein discharge devices are provided under the compacted iron storage tank and configured to supply the compacted iron to the third conveyance device, and the third conveyance device conveys the compacted iron to the first conveyance device.
The apparatus of claim 1, further comprising a carbon dioxide removal device for ramifying some of exhaust gas discharged from the multi-stage fluidized furnace, removing carbon dioxide from the ramified exhaust gas, adding the exhaust gas to the reducing gas supplied from the smelting furnace, and supplying the added reducing gas to the multi-stage fluidized furnace.
The apparatus of claim 1 or 10, further comprising a gas circulation cooling device for controlling temperature of reducing gas supplied to the multi-stage fluidized furnace by ramifying some of reducing gas generated from the smelting furnace, cooling the ramified reducing gas, and circulating the reducing gas supplied from the smelting furnace again.
A method of manufacturing molten iron, comprising the steps of:
reducing fine iron ores into reduced fine iron by using a multi-stage fluidized furnace;

manufacturing high-temperature compacted iron by compressing the reduced fine iron using a compacted iron manufacturing device;

crushing the high-temperature compacted iron by using a crushing device;

conveying the crushed compacted iron to a charging device; and

charging the compacted iron from the charging device into a smelting furnace and melting the charged compacted iron by combusting fine or lump coal.
The method of claim 12, further comprising the step of conveying some of the crushed compacted iron to a compacted iron storage tank.
The method of claim 13, further comprising the step of distributing the crushed compacted iron to the charging device or the compacted iron storage tank by using a 2-direction suits.
The method of claim 14, wherein:
if the high-temperature compacted iron necessary for the smelting furnace is able to be manufactured through the multi-stage fluidized furnace, the compacted iron manufacturing device, and the crushing device,

excess high-temperature compacted iron exceeding an amount of the high-temperature compacted iron necessary for the smelting furnace is manufactured, and

the excess high-temperature compacted iron is intermittently conveyed to and stored in the compacted iron storage tank by way of an action of the 2-direction suits.
The method of claim 13, wherein if the high-temperature compacted iron necessary for the smelting furnace is unable to be manufactured through the multi-stage fluidized furnace, the compacted iron manufacturing device, and the crushing device, the compacted iron stored in the compacted iron storage tank is continuously supplied to the smelting furnace via a conveyance device.
The method of any one of claims 12 to 16, wherein:
if a ratio of a yield of high-temperature compacted iron manufactured by the multi-stage fluidized furnace, the compacted iron manufacturing device, and the crushing device and demand quantity of high-temperature compacted iron necessary for the smelting furnace is defined by an excess rate as below,

the excess rate = (yield of the high-temperature compacted iron)/ (demand quantity of the high-temperature compacted iron) × 100,

the excess rate is 110 % to 120%.
The method of any one of claims 12 to 16, wherein a time that the high-temperature compacted iron stay in the compacted iron storage tank is 6 hours to 12 hours.