【DESCRIPTION】
【Invention Title】
MOLTEN IRON MANUFACTURING APPARATUS AND MOLTEN IRON
MANUFACTURING METHOD
【Technical Field5 】
The present invention relates to an apparatus for manufacturing molten
iron and a method of manufacturing molten iron. More particularly, the present
invention relates to an apparatus for manufacturing molten iron which
processes an exhaust gas using a chemical looping process, and a method of
10 manufacturing molten iron.
【Background Art】
A steam-iron process for producing hydrogen from a gaseous fuel,
which is a technology that was commercialized in the early 20th century,
produces pure hydrogen through repeated redox using iron as a medium (R. B.
15 Gupta, Hydrogen Fuel, CRC Press, 2009; L. S. Fan, Chemical Looping System
for Fossil Energy Conversions, Wiley, 2010).
This technology is one of chemical looping processes in the early stage
and does not require a water-gas shift reaction or a process of removing CO2 in
comparison to steam-methane reforming for mass production.
20 The steam-iron process has been developed to use a fixed-bed reactor
or a fluidized-bed reactor, and efficiency of the chemical looping process is
improved with development of technology regarding oxygen carrier particles
using iron (Fe) as a basic substance, so it is used to separate undesired
3
substances from a process exhaust gas.
Recently, rather than burning a mixture of air and fuel in a combustion
process for producing power using fossil fuel, a method of burning them in an
air-oxidation reaction and a fuel-reduction reaction using particles of a metal
such as iron, nickel, and copper as a medium has been used, so an exhaus5 t
gas can be naturally separated. Further, this technology has been spotlight
with respect to consuming a minimum cost for separating carbon dioxide.
In particular, as disclosed in Patent Documents (U.S. Patent: 6572761,
7404942, 7767191, 2010/0050654, and 2012/0006158), a chemical looping
10 process that uses a gas fuel (natural gas, synthetic gas, and the like), a solid
fuel (coal, coke, biomass, and the like), a liquid fuel, and a furnace exhaust gas
as a fuel and that uses a metallic medium such as iron or CaS/CaSO4 as
oxygen carrier particles can both produce power using combustion, and
separate carbon dioxide and produce hydrogen.
15 Iron used as oxygen carrier particles used in the documents is
inexpensive and a large amount of iron is available for the steel industry, so the
cost for obtaining it is low. Nevertheless, iron has a defect of poor activation
over a long period of time in repeated redox, so porous oxygen carrier particles
based on iron having a large surface area and shift efficiency are used.
20 Porous oxygen carrier particles have a support therein. Further, when
solid fuel such as coal is used, ash, sulfur (S), and nitrogen oxides (NOx)
should be separated.
However, those chemical looping processes are usually limited to a
process of generating power using combustion, even though they use iron,
4
which is widely used in the steel industry, as a medium.
The above information disclosed in this Background section is only for
enhancement of understanding of the background of the invention and therefore
it may include information that does not form the prior art that is already known
in this country to a person of ordinary skill in the ar5 t.
【DISCLOSURE】
【Technical Problem】
The present invention has been made in an effort to provide an
apparatus and a method of manufacturing molten iron which can efficiently
10 remove carbon dioxide produced in a process of producing molten iron and can
easily reduce hard-to-reduce iron ore.
【Technical Solution】
An exemplary embodiment of the present invention provides an
apparatus for manufacturing molten iron that includes: an iron ore-mixing/pre15
reducing furnace that receives and mixes natural iron ore and oxidized iron ore
supplied from an iron ore oxidizing-burning furnace, and heats or pre-reduces
iron ore using a flue gas supplied from an iron ore reduction furnace; the iron
ore reduction furnace that receives pre-processed iron ore discharged from the
iron ore-mixing/pre-reducing furnace or partially reduced iron ore, and reduces
20 the iron ore using a reduction gas discharged from a molten gasification
furnace; the molten gasification furnace that receives coal and some of reduced
iron produced by the iron ore reduction furnace and produces molten iron and a
reduction gas to be supplied to the iron ore reduction furnace; and the iron ore
5
oxidizing-burning furnace that receives new iron ore and some of reduced iron
discharged from the iron ore reduction furnace and changes the new iron ore
into oxidized iron ore including a large amount oxygen by burning the new iron
ore and the some of reduced iron with air.
The apparatus for manufacturing molten iron may further include 5 a
hydrogen producing device that produces hydrogen by reacting reduced iron,
which is produced by the iron ore reduction furnace and supplied to the iron ore
oxidizing-burning furnace, with steam, in which the reduced iron reacting with
the steam may be supplied to the iron ore oxidizing-burning furnace.
10 The apparatus for manufacturing molten iron may further include a
turbine that generates electricity using a gas discharged from the iron oremixing/
pre-reducing furnace.
The apparatus for manufacturing molten iron may further include an
exhaust gas processing device that changes carbon monoxide, which is in the
15 gas discharged from the iron ore-mixing/pre-reducing furnace, into hydrogen.
The exhaust gas processing device may include a water-gas shift
reactor and a hydrogen pressure swing adsorption (H2 PSA).
The hydrogen producing device may be connected with a hydrogen
supply line for supplying produced hydrogen to the iron ore reduction furnace.
20 Reduced iron put into the molten gasification furnace may be obtained
from the new iron ore that is oxidized in the iron ore oxidizing-burning furnace
and then reduced through the iron ore-mixing/pre-reducing furnace and the iron
ore reduction furnace or from the natural iron ore that is reduced through the
iron ore reduction furnace, supplied to the iron ore oxidizing-burning furnace to
6
be used as a trigger, and then reduced.
Another exemplary embodiment of the present invention provides a
method of manufacturing molten iron that includes: putting and mixing natural
iron ore and oxidized iron ore, which is supplied from a iron ore oxidizingburning
furnace, in an iron ore-mixing/pre-reducing furnace, and heating or pre5 -
reducing the iron ore with a flue gas supplied from an iron ore reduction
furnace; putting pre-processed iron ore or partially reduced iron supplied from
the iron ore-mixing/pre-reducing furnace into the iron ore reduction furnace, and
reducing the iron ore with a reduction gas discharged from a molten gasification
10 furnace; producing molten iron and a reduction gas to be supplied to the iron
ore reduction furnace, by putting coal and some of reduced iron produced by
the iron ore reduction furnace into the molten gasification furnace; and changing
new iron ore into oxidized iron ore including a large amount of oxygen by putting
the new iron ore and some of reduced iron discharged from the iron ore
15 reduction furnace, into the oxidizing-burning furnace, and burning the new iron
ore and the some of reduced iron with air.
The method may further include producing hydrogen by reacting some
of reduced iron, which is discharged from the iron ore reduction furnace, with
steam, in which the reduced iron ore reacting with the steam may be supplied to
20 the iron ore oxidizing-burning furnace.
The method may further include generating electricity by passing a flue
gas, which is discharged after heating or pre-reducing in the iron oremixing/
pre-reducing furnace, through a turbine.
The method may further include changing carbon monoxide in a flue gas,
7
which is discharged from the iron ore-mixing/pre-reducing furnace, into
hydrogen by passing the flue gas through a water-gas shift reactor and a
hydrogen pressure swing adsorption (H2 PSA), and supplying the changed
hydrogen to the iron ore reduction furnace.
Further, the method may further include supplying hydrogen produce5 d
by reaction between the reduced iron and the steam to the iron ore reduction
furnace.
The natural iron ore that is put into the iron ore-mixing/pre-reducing
furnace or the new iron ore that is put into the oxidizing-burning furnace may be
10 provided together with CaCO3 or MgCO3.
Further, the method may further include generating electricity by passing
a flue gas discharged from the iron ore oxidizing-burning furnace through the
turbine.
【Advantageous Effects】
15 According to the present invention, it is possible to produce hydrogen by
re-circulating reduced iron, separate carbon dioxide, and promote reduction of
hard-to-reduce iron ore.
Further, since natural iron ore is used, there is no need for producing
pre-processed oxygen carrier particles. Re-circulated reduced iron is used as
20 a trigger for burning hard-to-reduce iron ore such as magnetite and used as a
carrier for oxygen carrier particles and a trigger of a solid raw material in a
chemical looping process, so it is possible to easily reduce hard-to-reduce iron
ore.
8
【Description of the Drawings】
FIG. 1 is a diagram illustrating the configuration of an apparatus for
manufacturing molten iron according to a first exemplary embodiment of the
present invention.
FIG. 2 is a diagram illustrating the configuration of an apparatus fo5 r
manufacturing molten iron according to a second exemplary embodiment of the
present invention.
FIG. 3 is a diagram illustrating the configuration of an apparatus for
manufacturing molten iron according to a third exemplary embodiment of the
10 present invention.
【Mode for Invention】
Hereinafter, exemplary embodiments of the present invention will be
described in detail with reference to the accompanying drawings so that those
skilled in the art can easily achieve the present invention. The present
15 invention may be implemented in various ways and is not limited to the
exemplary embodiments described herein. Like reference numerals indicate
like components in the specification and drawings.
FIG. 1 is a diagram of an apparatus for manufacturing molten iron
according to an exemplary embodiment of the present invention.
20 Referring to FIG. 1, an apparatus 101 for manufacturing molten iron
according to the present exemplary embodiment includes a molten gasification
furnace 10, an iron ore reduction furnace 20, an iron ore-mixing/pre-reducing
furnace 30, and an oxidizing-burning furnace 40.
The molten gasification furnace 10 is filled with coal and some of
9
reduced iron reduced through the iron ore reduction furnace 20, and produces
molten iron and a reduction gas to be supplied to the iron ore reduction furnace
20. A pulverized-coal supply line 11, an oxygen supply line 12, a coal supply
line 13, and a first reduced iron supply line 21 are connected to the molten
gasification furnace 105 .
Air or oxygen is supplied into the molten gasification furnace 10 through
the oxygen supply line 12, and pulverized coal is supplied into the molten
gasification furnace 10 through the pulverized-coal supply line 11. Further,
coal is supplied into the molten gasification furnace 10 through the coal supply
10 line 13, and the first reduced iron supply line 21 is disposed between the molten
gasification furnace 10 and the iron ore reduction furnace 20 and sends
reduced iron produced through the iron ore reduction furnace 20 into the molten
gasification furnace 10.
The reduced iron to be supplied into the molten gasification furnace 10
15 is supplied from the outside, and new iron ore including a large amount of
natural magnetite can be supplied through the first reduced iron supply line 21
after being oxidized by air through the oxidizing-burning furnace 40 and reduced
through the iron ore reduction furnace 20.
Further, the reduced iron may be obtained by heating and pre-reducing
20 natural iron ore through the iron ore-mixing/pre-reducing furnace 30 and then
reducing it through the iron ore reduction furnace 20.
Further, the reduced iron may be reduced through the iron ore reduction
furnace 20 and some of the reduced iron may be used as an oxidation catalyst
by the oxidizing-reducing furnace 40 and then supplied through the first reduced
10
iron supply line 21 after passing through the iron ore-mixing/pre-reduction
furnace 30 and the iron ore reduction furnace 20 .
Further, a reduction gas supply line 15 connected to the iron ore
reduction furnace 20 is connected to the molten gasification furnace 10, so a
reduction gas produced by melting of iron ore is supplied into the iron or5 e
reduction furnace 20 through the reduction gas supply line 15.
High heat of 1400 C to 1600 C and a reduction gas mainly including
carbon monoxide and hydrogen are produced by combustion of oxygen, coal,
and pulverized coal in the molten gasification furnace 10. The reduction gas
10 supplies heat to the molten gasification furnace 10, removes oxygen from
reduced iron, and reduces and melts the reduced iron. Accordingly, iron ore is
divided into gangue and coal in molten iron and iron ore, ash in pulverized-coal,
and slag of other materials. A molten iron discharge line 14 is connected to
the molten gasification furnace 10 to discharge molten iron and slag.
15 Coal may be supplied as pre-coke, or briquette-type coal (coal
briquettes) through pre-processing, and air can be supplied to the molten
gasification furnace 10, but oxygen may be supplied to the molten gasification
furnace 10 for easy separation of carbon dioxide from a reaction gas to reduce
the carbon dioxide.
20 The iron ore reduction furnace 20 is a device that is filled with preprocessed
iron ore or partially reduced iron discharged from the iron oremixing/
pre-reducing furnace 30, and reduces iron ore using the reduction gas
discharged from the molten gasification furnace 10.
An iron ore supply line 31 connected to the iron ore-mixing/pre-reducing
11
furnace 30 to send iron ore from the iron ore-mixing/pre-reducing furnace 30 to
the iron ore reduction furnace 20 is connected to the iron ore reduction furnace
20. Further, the reduction gas supply line 15 for supplying a high-temperature
reduction gas produced through the molten gasification furnace 10 to the iron
ore reduction furnace 20 is disposed between the molten gasification furnace 5 10
and the iron ore reduction furnace 20. Further, a reaction gas supply line 24
for supplying a reaction gas having reduction ability from the iron ore reduction
furnace 20 to the iron ore-mixing/pre-reducing furnace 30 is connected to the
iron ore reduction furnace 20 and the iron ore-mixing/pre-reducing furnace 30.
10 The high-temperature reduction gas supplied from the molten
gasification furnace 10, which is produced by combustion of air or oxygen, coal,
and pulverized coal, after reducing and melting iron ore, mainly includes carbon
monoxide, hydrogen, carbon dioxide, or nitrogen, and small amounts of vapor,
methane, and oxygen. Further, the reaction gas produced in the iron ore
15 reduction furnace 20 includes a reductive gas component such as carbon
monoxide and hydrogen.
As expressed in the following [Chemical Equation 1] and [Chemical
Equation 2], iron ore changes from a state (Fe2O3, Fe3O4) including a large
amount of oxygen into reduced iron (FeOx, Fe) including a small amount of
20 oxygen by reacting with a reduction gas in the iron ore reduction furnace 20.
In this case, X is in the range of 0 to 1. Further, as expressed in [Chemical
Equation 3], the reduction gas changes into carbon dioxide and water by a
water-gas shift reaction. That is, carbon monoxide and hydrogen is removed
from oxygen from iron ore and changes into carbon dioxide and vapor.
12
[Chemical Equation 1]
1/3 Fe2O3 + CO/H2 ----> 2/3 Fe + CO2/H2O
[Chemical Equation 2]
1/4 Fe3O4 + CO/H2 ----> 3/4 Fe + CO2/H2O
[Chemical Equation 5 3]
CO + H2O ----> CO2 + H2
A second reduced iron supply line 26 for supplying reduced iron to the
iron ore oxidizing-burning furnace 40 is connected to the iron ore reduction
furnace 20 and the iron ore oxidizing-burning furnace 40. Some of the iron ore
10 reduced in the iron ore reduction furnace 20 is supplied to the iron ore oxidizingburning
furnace 40 through the second reduced iron supply line 26.
The circulation amount of the reduced iron supplied from the iron ore
reduction furnace 20 to the iron ore oxidizing-burning furnace 40 can be flexibly
adjusted, depending on the amount of hydrogen produced by a hydrogen
15 producing device, the supply amount of new iron ore, and the supply amount of
natural iron ore. That is, in order to produce a large amount of hydrogen, the
supply amount of new iron ore is increased and the supply amount of natural
iron ore to the iron ore oxidizing-burning furnace 40 is reduced, thereby
increasing the production amount of hydrogen. Further, in order to increase
20 the amount of natural iron ore to be supplied to the iron ore oxidizing-burning
furnace 40, the productivity of molten iron is adjusted by adjusting the amount of
recirculation of reduced iron by reducing the production amount of hydrogen
and the supply amount of new iron ore.
Further, a first reduced iron supply line 21 for supplying reduced iron to
13
the molten gasification furnace 10 is connected to the iron ore reduction furnace
20 and the molten gasification furnace 10. That is, some of reduced iron ore is
supplied to the iron ore oxidizing-burning furnace 40 through the second
reduced iron supply line 26, and the rest is supplied to the molten gasification
furnace 10 through the first reduced iron supply line 21 and changed into molte5 n
iron.
The iron ore reduction furnace 20 may be a fixed-bed reactor, a moving
bed reactor, or a fluidized-bed reactor. When reduced iron exists in the type of
pellets or briquettes, the iron ore reduction furnace 20 is a fixed-bed reactor or a
10 moving bed reactor, and when reduced iron exists in the type of pulverized-iron
ore, it is a fluidized-bed reactor. The iron ore reduction furnace 20 may be
composed of a plurality of reactors connected in series or in parallel.
The reaction temperature of the iron ore reduction furnace 20 may be
600 C to 1000 C, and the reaction pressure of the iron ore reduction furnace
15 20 may be 10 bar or less at room temperature.
The iron ore-mixing/pre-reducing furnace 30 is a device that receives
and mixes natural iron ore and oxidized iron ore supplied from the iron ore
oxidizing-burning furnace 40, and heats or pre-reduces iron ore using a flue gas
(supply gas) supplied from the iron ore reduction furnace 20.
20 Natural iron ore (Fe2O3) supplied from the outside and including a large
amount of oxygen and oxidized iron ore (Fe2O3, Fe3O4) obtained from the iron
ore oxidizing-burning furnace 40 are put into the iron ore-mixing/pre-reducing
furnace 30 and mixed therein. Further, the iron ore-mixing/pre-reducing
furnace 30 may have a drying furnace for removing moisture from natural iron
14
ore.
An oxidized iron supply line 43 connected to the oxidizing-burning
furnace 40 to supply oxidized iron from the oxidizing-burning furnace 40 to the
iron ore-mixing/pre-reducing furnace 30 is connected to the iron ore-mixing/prereducing
furnace 30. Further, an iron ore supply line 45 for supplying natura5 l
iron ore is connected to the oxidized iron supply line 43.
The iron ore oxidized in the iron ore oxidizing-burning furnace 40 is at a
high temperature, is mixed with natural iron ore supplied from the outside, and
is supplied to the iron ore-mixing/pre-reducing furnace 30. Since the oxidized
10 iron ore from the iron ore oxidizing-burning furnace 40 is at a high temperature,
it heats natural iron ore by being mixed with the natural iron ore.
A reaction gas supplied from the iron ore reduction furnace 20 through
the reaction gas supply line 24 supplies heat to the iron ore-mixing/pre-reducing
furnace 30, and carbon monoxide (CO) and hydrogen (H2) that are reductive
15 gas components change iron ore obtained by separating oxygen from iron ore
into reduced irons (Fe3O4, FeOx) including a small amount of oxygen. The
reaction gas adjusts the heat in the iron ore-mixing/pre-reducing furnace 30 by
enhancing mixing of natural iron ore and oxidized iron ore.
In the present exemplary embodiment, although it is exemplified that
20 natural iron ore and oxidized iron ore are mixed and the mixture is supplied to
the iron ore-mixing/pre-reducing furnace 30, the present invention is not limited
thereto. When only high-temperature oxidized iron ore obtained from the
oxidizing-burning furnace 40 is supplied without natural iron ore, the oxidized
iron ore adjusts heat by coming in contact with a rising gas, and carbon
15
monoxide (CO) and hydrogen (H2) that are remaining reductive gases can
enhance reduction ability for removing oxygen by acting on the iron ore.
A flue gas exhaust pipe 32 for discharging a flue gas produced by a
reaction is connected to the iron ore-mixing/pre-reducing furnace 30. The flue
gas discharged from the iron ore-mixing/pre-reducing furnace 30 can be use5 d
for generating power, and carbon dioxide may be kept or reused through an
exhaust gas processing device.
Further, reduced iron produced in the iron ore-mixing/pre-reducing
furnace 30 is supplied to the iron ore reduction furnace 20 through the iron
10 supply line 31 connected to the iron ore-mixing/pre-reducing furnace 30 and the
iron ore reduction furnace 20. Natural iron ore dried in the iron ore-mixing/prereducing
furnace 30 is mixed with high-temperature oxidized iron ore having a
temperature of 650 C to 1100 C.
Oxidized iron ore supplied from the oxidizing-burning furnace 40 mainly
15 includes Fe2O3 and Fe3O4. The iron ore supplied to the iron ore-mixing/prereducing
furnace 30 receives heat from a reaction gas supplied from the iron
ore reduction furnace 20, and carbon monoxide and hydrogen that are reductive
gas components change the state of the iron ore into a state including a small
amount of oxygen by removing oxygen from the iron ore. Further, the flue gas
20 exhaust pipe 32 for discharging a produced flue gas is connected to the iron
ore-mixing/pre-reducing furnace 30, and a turbine that generates power using
the gas discharged from the iron ore-mixing/pre-reducing furnace 30 is
disposed in the flue gas exhaust pipe 32.
The iron ore-mixing/pre-reducing furnace 30 may be a fixed-bed reactor,
16
a moving bed reactor, or a fluidized-bed reactor, and when the iron oremixing/
pre-reducing furnace 30 is a fluidized-bed reactor, it is possible to more
uniformly mix natural iron ore with oxidized iron ore, using the reaction gas
supplied from the iron ore reduction furnace 20.
The reaction temperature of the iron ore-mixing/pre-reducing furnace 35 0
is 350 C to 750 C, depending on the iron ore reduction furnace 20, and the
pressure of the iron ore-mixing/pre-reducing furnace 30 may be 10 bar or less
at room temperature.
The oxidizing-burning furnace 40 is a device that receives natural
10 magnetite or new iron ore and some of the reduced iron discharged from the
iron ore reduction furnace 20, and changes the new iron ore into oxidized iron
ore including a large amount oxygen by burning the magnetite and some of the
reduced iron with air. The second reduced iron supply line 26 for supplying
reduced iron to the iron ore oxidizing-burning furnace 40 from the iron ore
15 reduction furnace 20 is connected to the iron ore oxidizing-burning furnace 40.
Further, an air supply line 42 for supplying air to the oxidizing-burning
furnace 40 and a new iron ore supply line 41 for supplying new iron ore to the
oxidizing-burning furnace 40 from the outside are connected to the oxidizingburning
furnace 40. The new iron ore to be supplied to the oxidizing-burning
20 furnace 40 may be iron ore (Fe3O4) mainly including Fe at 60 wt% or more (FeO
at 20 wt% or more) or Fe at 50 wt% or more (FeO at 10 wt% or more), gangue
component such as SiO2, Al2O3, CaO, and MgO at 10 wt% or 20 wt% or less,
and the balance of O2.
Further, the oxidized iron supply line 43 for supplying oxidized iron to the
17
iron ore-mixing/pre-reducing furnace 30 and a flue gas exhaust line 46 for
discharging a high-temperature flue gas produced in the oxidizing-burning
furnace 40 are connected to the oxidizing-burning furnace 40.
The reduced iron supplied through the second reduced iron supply line
26 is burned with supplied air into oxidized iron, and the new iron ore supplie5 d
to the oxidizing-burning furnace 40 is heated by the heat generated in this
process. Further, the heated new iron ore is burned by reacting with air and
the burned new iron ore makes a chain reaction of changing into oxidized iron.
The supplied air may be high-temperature air at 900 C or less, and air
10 supplies oxygen for combustion to reduced iron and heated iron ore that
function as triggers, and is discharged at a high temperature with less oxygen
from a reactor.
The oxidizing-burning furnace 40 may be a fixed-bed reactor, a moving
bed reactor, or a fluidized-bed reactor, and particularly, the oxidizing-burning
15 furnace 40 may be a fluidized-bed riser reactor. When the oxidizing-burning
furnace 40 is a riser reactor that is a kind of fluidized-bed reactors, it is
advantageous for a chain combustion reaction of iron ore.
When the oxidizing-burning furnace 40 is a riser reactor, a trigger of a
solid raw material generates heat by burning and intensively reacting with the
20 oxygen in the air supplied from the lower end of the reactor, and changes new
iron ore supplied from above the lower end of the reactor into a trigger by
heating it.
The changed trigger of a solid raw material heats new iron ore that is
continuously supplied through a riser reaction pipe while rising through the riser
18
reaction pipe, generates a chain reaction for changing into a trigger, and is
changed into oxidized iron having high-temperature heat.
The oxidizing-burning furnace 40 may include a plurality of reactors
arranged in parallel. The processing temperature of the oxidizing-burning
furnace 40 is maintained at 700 C to 1200 C such that new iron ore that i5 s
supplied is heated and oxidized, and the discharge flue gas generates electricity
by passing through the turbine, in which the pressure of the reactor is around 30
bar at room temperature for efficient power generation. Pressure in this
process may be controlled by compressed air that is supplied.
10 A method of manufacturing molten iron according to the present
exemplary embodiment is described hereafter.
A method of manufacturing molten iron according to the present
exemplary embodiment includes: putting and mixing natural iron ore and
oxidized iron ore, which is supplied from the iron ore oxidizing-burning furnace
15 40, in the iron ore-mixing/pre-reducing furnace 30, and heating or pre-reducing
the iron ore with a flue gas supplied from the iron ore reduction furnace 20;
putting pre-processed iron ore or partially reduced iron supplied from the iron
ore-mixing/pre-reducing furnace 30 into the iron ore reduction furnace 20, and
reducing the iron ore with a reduction gas discharged from the molten
20 gasification furnace; producing molten iron and a reduction gas to be supplied
to the iron ore reduction furnace 20, by putting coal and some of reduced iron
produced by the iron ore reduction furnace 20 into the molten gasification
furnace 10; and changing new iron ore into oxidized iron ore including a large
amount of oxygen, by putting the new iron ore and some of reduced iron
19
discharged from the iron ore reduction furnace 20 into the iron ore oxidizingburning
furnace 40, and burning the new iron ore and the some of reduced iron
with air.
The method of manufacturing molten iron according to the present
exemplary embodiment may further include generating electricity by passing 5 a
flue gas, which is discharged after heating or pre-reducing in the iron oremixing/
pre-reducing furnace 30, through a turbine.
Further, the method of manufacturing molten iron according to the
present exemplary embodiment may further include generating electricity by
10 passing a flue gas discharged from the iron ore oxidizing-burning furnace 40
through a turbine.
FIG. 2 is a diagram illustrating the configuration of an apparatus for
manufacturing molten iron according to a second exemplary embodiment of the
present invention.
15 Referring to FIG. 2, an apparatus 102 for manufacturing molten iron
according to a second exemplary embodiment of the present invention is the
same in structure as the apparatus for manufacturing molten iron according to
the first exemplary embodiment described above, except that an exhaust gas
processing device 60 is connected to a hydrogen producing device 50 and the
20 iron ore-mixing/pre-reducing furnace 30, so the same configuration is not
described.
The hydrogen producing device 50 is a device that produces hydrogen
by reacting reduced iron, which is produced by an iron ore reduction furnace 20
and supplied to an iron ore oxidizing-burning furnace 40, with steam.
20
The hydrogen producing device 50 is a device that produces hydrogen
by reacting reduced iron, which is supplied from the iron ore reduction furnace
20, with steam through a catalyst. A third reduced iron supply line 23
connected to the iron ore reduction furnace 20 to receive the reduced iron
produced by the iron ore reduction furnace 20 is connected to the hydroge5 n
producing device 50. A steam supply line 51 for supplying steam, a hydrogen
exhaust pipe 53, and a trigger supply line 52 for supplying a trigger produced in
the hydrogen producing device 50 to the oxidizing-burning furnace 40 are
connected to the hydrogen producing device 50.
10 The reduced iron ore supplied from the iron ore reduction furnace 20
produces hydrogen by causing an oxidation reaction with steam 58 through a
catalyst and changes into a trigger by oxidizing. The steam 58 provides
oxygen to reduced iron in the hydrogen producing device 50 and changes into
hydrogen. The steam 58 may be supplied from the outside.
15 The hydrogen exhaust pipe 53 is connected to a heat exchanger 56, so
steam produced by heat exchange of high-temperature hydrogen can supply
steam to the hydrogen producing device 50 through the steam supply line 51.
The hydrogen producing device 50 may be a fixed-bed reactor, a
moving bed reactor, or a fluidized-bed reactor. The reaction temperature of
20 the hydrogen producing device 50 may be 600 C to 1000 C, depending on the
reduced iron supplied from the iron ore reduction furnace 20, and the reaction
pressure of the hydrogen producing device 50 may be 30 bar or less at room
temperature.
The trigger supplied to the iron ore oxidizing-burning furnace 40 through
21
the trigger supply line 52 changes into oxidized iron by burning with air, in which
new iron ore supplied to the iron ore oxidizing-burning furnace 40 is heated by
the heat generated in this process. The heated new iron ore changes into a
trigger and burns by reacting with air, and the burned new iron ore makes a
chain reaction of changing into oxidized iron5 .
The exhaust gas processing device 60 is connected to the flue gas
exhaust pipe 32 of the iron ore-mixing/pre-reducing furnace 30, and is a device
for changing carbon monoxide, which is in the gas discharged from the exhaust
gas processing device 60, into hydrogen. The exhaust gas processing device
10 60 may include a water-gas shift reactor and a hydrogen pressure swing
adsorption. The exhaust gas processing device 60 can separate carbon
dioxide and produce a reduction gas including hydrogen.
A carbon dioxide exhaust pipe 62 and a reduction gas supply line 61 are
connected to the exhaust gas processing device 60. A gas including carbon
15 dioxide in a high concentration discharged through the carbon dioxide exhaust
pipe 62 may be kept under the ground or reused. The reduction gas supply
line 61 is connected to the iron ore reduction furnace 20, and carries a reduction
gas including a large amount of hydrogen to the iron ore reduction furnace 20.
In addition to the method of manufacturing molten iron according to the
20 first exemplary embodiment described above, the method of manufacturing
molten iron according to the present exemplary embodiment further includes
producing hydrogen by reacting some of reduced iron discharged from the iron
ore reduction furnace 20 with steam, in which the reduced iron reacting with the
steam is supplied to the iron ore oxidizing-burning furnace 40.
22
The method of manufacturing molten iron according to the present
exemplary embodiment further includes changing carbon monoxide in the flue
gas, which is discharged from the iron ore-mixing/pre-reducing furnace 30, into
hydrogen by passing the flue gas through a water-gas shift reactor and a
hydrogen pressure swing adsorption (H2 PSA), and supplying the change5 d
hydrogen to the iron ore reduction furnace.
FIG. 3 is a diagram illustrating the configuration of an apparatus for
manufacturing molten iron according to a third exemplary embodiment of the
present invention.
10 Referring to FIG. 3, an apparatus 103 for manufacturing molten iron
according to a third exemplary embodiment of the present invention is the same
in structure as the apparatus for manufacturing molten iron according to the
second exemplary embodiment, except that a hydrogen supply line 54 is
connected to the hydrogen producing device 50, so the same configuration is
15 not described.
The hydrogen supply line is connected to the hydrogen producing
device 50 and the iron ore reduction furnace 20, and supplies hydrogen
produced by the hydrogen producing device 50 to the iron ore reduction furnace
20. When hydrogen is supplied to the iron ore reduction furnace 20, reduction
20 ability is increased and iron ore can be more efficiently reduced, so a load on
the molten gasification furnace 10 can be reduced.
When more molten iron needs to be produced or there is a need for
reducing the amount of a reducer, hydrogen is supplied to the iron ore reduction
furnace 20 through the hydrogen supply line 54, and in other cases, hydrogen is
23
supplied to the outside. A sub-iron ore material such as calcium carbonate
(CaCO3) or magnesium carbonate (MgCO3) may be additionally supplied with
natural iron ore in order to supplement heat generated by the oxidizing-burning
furnace 40 and easily separate slag and molten iron in the molten gasification
furnace 105 .
The calcium carbonate (CaCO3) can be re-circulated while supplying
heat by changing into calcium oxide (CaO) in the iron ore oxidizing-burning
furnace 40 and enhancing reduction ability of a reduction furnace by recovering
and filtering carbon dioxide in the iron ore-mixing/pre-reducing furnace 30 or the
10 iron ore reduction furnace 20.
The method of manufacturing molten iron according to the present
exemplary embodiment further includes supplying hydrogen produced by a
reaction between reduced iron and steam to the iron ore reduction furnace, in
addition to the method of manufacturing molten iron according to the second
15 exemplary embodiment described above.
The natural iron ore that is put into the iron ore-mixing/pre-reducing
furnace 30 or the new iron ore that is put into the iron ore oxidizing-burning
furnace 40 is provided together with CaCO3 or MgCO3.
While this invention has been described in connection with what is
20 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】
【Claim 1】
An apparatus for manufacturing molten iron, comprising:
an iron ore-mixing/pre-reducing furnace that receives and mixes natural
iron ore and oxidized iron ore supplied from an iron ore oxidizing-burnin5 g
furnace, and heats or pre-reduces iron ore using a flue gas supplied from an
iron ore reduction furnace;
the iron ore reduction furnace that receives pre-processed iron ore
discharged from the iron ore-mixing/pre-reducing furnace or partially reduced
10 iron ore, and reduces the iron ore using a reduction gas discharged from a
molten gasification furnace;
the molten gasification furnace that receives coal and some of reduced
iron produced by the iron ore reduction furnace and produces molten iron and a
reduction gas to be supplied to the iron ore reduction furnace; and
15 the iron ore oxidizing-burning furnace that receives new iron ore and
some of reduced iron discharged from the iron ore reduction furnace and
changes the new iron ore into oxidized iron ore including a large amount of
oxygen by burning the new iron ore and the some reduced iron with air.
20 【Claim 2】
The apparatus of claim 1, further comprising
a hydrogen producing device that produces hydrogen by reacting
reduced iron, which is produced by the iron ore reduction furnace and supplied
25
to the iron ore oxidizing-burning furnace, with steam,
wherein the reduced iron reacting with the steam is supplied to the iron
ore oxidizing-burning furnace.
【Claim 5 3】
The apparatus of claim 2, further comprising
a turbine that generates electricity using a gas discharged from the iron
ore-mixing/pre-reducing furnace.
10 【Claim 4】
The apparatus of claim 2, further comprising
an exhaust gas processing device that changes carbon monoxide,
which is in the gas discharged from the iron ore-mixing/pre-reducing furnace,
into hydrogen.
15
【Claim 5】
The apparatus of claim 4, wherein
the exhaust gas processing device includes a water-gas shift reactor
and a hydrogen pressure swing adsorption (H2 PSA).
20
【Claim 6】
The apparatus of claim 5, wherein
the hydrogen producing device is connected with a hydrogen supply line
26
for supplying produced hydrogen to the iron ore reduction furnace.
【Claim 7】
The apparatus of claim 1, wherein
reduced iron put into the molten gasification furnace is obtained from 5 the
new iron ore that is oxidized in the iron ore oxidizing-burning furnace and then
reduced through the iron ore-mixing/pre-reducing furnace and the iron ore
reduction furnace or from the natural iron ore that is reduced through the iron
ore reduction furnace, supplied to the iron ore oxidizing-burning furnace to be
10 used as a trigger, and then reduced.
【Claim 8】
A method of manufacturing molten iron, comprising:
putting and mixing natural iron ore and oxidized iron ore, which is
15 supplied from an iron ore oxidizing-burning furnace, in an iron ore-mixing/prereducing
furnace, and heating or pre-reducing the iron ore with a flue gas
supplied from an iron ore reduction furnace;
putting pre-processed iron ore or partially reduced iron supplied from the
iron ore-mixing/pre-reducing furnace into the iron ore reduction furnace, and
20 reducing the iron ore with a reduction gas discharged from a molten gasification
furnace;
producing molten iron and a reduction gas to be supplied to the iron ore
reduction furnace, by putting coal and some of reduced iron produced by the
iron ore reduction furnace into the molten gasification furnace; and
27
changing new iron ore into oxidized iron ore including a large amount of
oxygen by putting the new iron ore and some of reduced iron discharged from
the iron ore reduction furnace into the oxidizing-burning furnace, and burning
the new iron ore and the some of reduced iron with air.
5
【Claim 9】
The method of claim 8, further comprising
producing hydrogen by reacting some of reduced iron, which is
discharged from the iron ore reduction furnace, with steam,
10 wherein the reduced iron ore reacting with the steam is supplied to the
iron ore oxidizing-burning furnace.
【Claim 10】
The method of claim 9, further comprising
15 generating electricity by passing a flue gas, which is discharged after
heating or pre-reducing in the iron ore-mixing/pre-reducing furnace, through a
turbine.
【Claim 11】
20 The method of claim 9, further comprising
changing carbon monoxide in a flue gas, which is discharged from the
iron ore-mixing/pre-reducing furnace, into hydrogen by passing the flue gas
through a water-gas shift reactor and a hydrogen pressure swing adsorption (H2
28
PSA), and supplying the changed hydrogen to the iron ore reduction furnace.
【Claim 12】
The method of claim 10 or 11, further comprising
supplying hydrogen produced by reaction between the reduced iron an5 d
the steam to the iron ore reduction furnace.
【Claim 13】
The method of claim 12, wherein
10 the natural iron ore that is put into the iron ore-mixing/pre-reducing
furnace or the new iron ore that is put into the oxidizing-burning furnace is
provided together with CaCO3 or MgCO3.
【Claim 14】
15 The method of claim 13, further comprising
generating electricity by passing a flue gas discharged from the iron ore
oxidizing-burning furnace through the turbine.