【Invention Title】
MOLTEN IRON MANUFACTURING APPARATUS AND MOLTEN IRON
MANUFACTURING METHOD
5 【Technical Field】
The present invention relates to an apparatus and method for
manufacturing molten iron. More particularly, the present invention relates to
an apparatus and method for manufacturing molten iron that process a flue gas
using a medium circulation process.
10 【Background Art】
Power generation mostly depends on fossil fuel and particularly, power
generation using a heat that is generated by burning coal was started together
with a modern steam turbine that is invented by Parsons of England at the end
of the 19 century.
15 A steam turbine generates a heat by burning coal, air, or steam within a
boiler reactor and generates power by recovering the heat into steam.
However, although a steam turbine occupies most of a power generation
method, due to low efficiency, power generation using the steam turbine is
developed into complex power generation that sequentially uses a refine gas of
20 a high temperature that removes a pollution material such as ash by a coal gas
in a gas turbine and a steam turbine.
In this case, for higher heat efficiency and long time use of a low
process apparatus, a gas that passes through a gas turbine requires a high
2
temperature state of 1100°C or more that does not include ash and a harmful
material. In power generation by such a coal gas, in order to reduce discharge
of carbon dioxide that is generated when generating power, a carbon dioxide
collection apparatus or an apparatus for separating oxygen from air is required.
Nowadays, in order to solve such a problem, 5 a chemical looping
combustion process has been developed. Particularly, a document (U.S.
Patent US6572761, USS7404942, US7767191, and US2010/0050654)
suggested a method of efficiently performing power generation through carbon
dioxide separation or hydrogen production directly using solid fuel such as coal
10 or biomass.
A medium circulation process was invented (U.S. Patent US2665971)
with a method of obtaining pure carbon dioxide at the early 1950s and was
invented to reduce heat consumption in a process without including a nitrogen
gas in carbon dioxide.
15 A medium circulation process uses an oxygen providing particle of solid
oxide circulating two reactors, and in a reduction reactor, fossil fuel receives the
supply of oxygen from solid oxide to perform a complete oxidation reaction,
thereby generating pure carbon dioxide. Further, in the oxidation reactor,
circulating solid oxide in which oxygen is deficient receives the supply of oxygen
20 from air to be oxidized and returns to a reduction reactor and performs a
function that supplies a heat.
In this case, an oxygen providing particle, which is solid oxide is formed
with nickel (Ni) and iron (Fe)-based metal particle having a support and an
3
oxygen providing particle, iron (Fe)-based metal oxide that can use with a low
cost is preferred. This is because activation of oxygen providing particles
circulating while performing a repeated oxidation and reduction reaction is
deteriorated by impurities and thus oxygen providing particles should be
periodically 5 replaced.
Such a medium circulation process has been developed into a chemical
looping combustion process that generates pure carbon dioxide that does not
include a nitrogen gas by reforming a methane gas in a reduction reactor using
an oxygen providing particle as a medium and that generates power with a
10 refine gas of a high temperature that is generated by injecting air that contains
moisture in an oxidation reactor (U.S. Patent 5447024).
For transport to the underground and storage at the underground, as
carbon dioxide that is generated at this time, high concentration carbon dioxide
having no pollution material of a high pressure is preferred. Therefore, in
15 power generation by a chemical looping combustion process, in a process, an
oxygen separation device is unnecessary, and a discharge gas is naturally
separated.
The above information disclosed in this Background section is only for
enhancement of understanding of the background of the invention and therefore
20 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.
【DISCLOSURE】
【Technical Problem】
4
The present invention has been made in an effort to provide an
apparatus and method for manufacturing molten iron having advantages of
being capable of efficiently removing carbon dioxide from a flue gas that is
generated in a molten iron production process, generating power, and removing
dust that has occurred 5 in a process.
【Technical Solution】
An exemplary embodiment of the present invention provides a molten
iron manufacturing apparatus including: an iron ore reduction furnace that
produces reduced iron by charging iron ore and injecting a reduced gas; a
10 melting gas furnace that produces a reduced gas to provide to the iron ore
reduction furnace and molten iron by filling coal and by charging reduced iron
that is reduced and discharged in the iron ore reduction furnace; a gas
purification filter type reduction furnace that reduces sintered ore by charging
the sintered ore and injecting a process gas that is discharged after reducing
15 iron ore in the iron ore reduction furnace; a micro dust removal device that
removes dust from reduced sintered ore that is reduced and discharged in the
gas purification filter type reduction furnace; and an oxidation combustion
furnace that oxidizes reduced sintered ore by charging the reduced sintered ore
in which dust is removed and burning the sintered ore together with air.
20 In the oxidation combustion furnace, an oxidized sintered ore supply line
for supplying oxidized sintered ore to the gas purification filter type reduction
furnace may be installed.
In the gas purification filter type reduction furnace, a first reduced
5
sintered ore supply line that supplies a portion of the discharged reduced
sintered ore to the melting gas furnace and a second reduced sintered ore
supply line that supplies the remaining portions of the reduced sintered ore to
the micro dust removal device may be installed.
The sintered ore may be ore that mixes iron ore powder, 5 limestone, and
coal of a natural state and that is heated, recrystallized, or is fired in a halfmelting
state in a range of 900℃-1,400℃ and that is pulverized to 1mm-10mm.
The remaining portions of the reduced sintered ore may include
differentiated ore of sintered ore of FeO or Fe that is discharged after providing
10 oxygen to carbon monoxide and hydrogen in the gas purification filter type
reduction furnace, dust that is separated from the process gas, and sintered ore
that is generated in an oxidation and reduction reaction of a repeated medium
circulation method.
In the oxidation combustion furnace, in order to supplement an amount
15 of the reduced sintered ore that is supplied to the melting gas furnace and to
accelerate activation thereof, new sintered ore may be additionally supplied.
The molten iron manufacturing apparatus may further include: a heat
exchange device that separates carbon dioxide and that produces steam of a
high temperature by converting water vapor within a flue gas to water by
20 exchanging a heat of the flue gas that is discharged from the gas purification
filter type reduction furnace; and a steam turbine that generates electricity from
steam that is generated by the heat exchange device.
A heat quantity that is generated when sintered ore that is reduced in
6
the oxidation combustion furnace is fired with oxygen in the air may be supplied
to the new sintered ore, air, and reduced sintered ore that is supplied from the
micro dust removal device.
The molten iron manufacturing apparatus may further include a gas
turbine that generates electricity from air in which oxygen is deficient 5 and that is
discharged after supplying oxygen for combustion to new sintered ore and
reduced sintered ore in the oxidation combustion furnace or a steam turbine
that produces steam by heat exchange of air in which oxygen is deficient and
that generates electricity using the produced steam.
10 The molten iron manufacturing apparatus may further include a carbon
dioxide removal device that is connected to the gas purification filter type
reduction furnace to remove carbon dioxide from a flue gas that is discharged
from the gas purification filter type reduction furnace.
The flue gas that is discharged from the gas purification filter type
15 reduction furnace may produce steam by heat exchange, generate electricity by
rotating a steam turbine with the produced steam, remove water, and be
supplied to the carbon dioxide removal device.
In the carbon dioxide removal device, a recirculation gas supply line for
reinjecting a gas purification filter type reduction furnace flue gas in which
20 carbon dioxide is removed to the gas purification filter type reduction furnace
may be installed.
The carbon dioxide removal device may include a water-gas shift
reactor and a hydrogen pressure swing adsorption device.
7
A gas purification device that removes dust from a process gas that is
discharged from the iron ore reduction furnace may be installed at the front end
of the gas purification filter type reduction furnace.
The gas purification device may be at least one that is selected from a
cyclone, a ceramic candle filter, a metal filter, 5 and a scrubber.
In the oxidation combustion furnace, a heat exchange device for heating
injected air may be installed at the front end of the oxidation combustion furnace.
Another embodiment of the present invention provides a molten iron
manufacturing apparatus including: an iron ore reduction furnace that produces
10 reduced iron by charging iron ore and injecting a reduced gas; a melting gas
furnace that produces a reduced gas to provide to the iron ore reduction furnace
and molten iron by filling coal and by charging reduced iron that is reduced and
discharged in the iron ore reduction furnace; a gas purification filter type
reduction furnace that reduces a fired pellet by charging the fired pellet and
15 injecting a process gas that is discharged after reducing iron ore in the iron ore
reduction furnace; a micro dust removal device that removes dust from the
reduced fired pellet that is reduced and discharged in the gas purification filter
type reduction furnace; and an oxidation combustion furnace that oxidizes a
reduced fired pellet by charging a reduced fired pellet in which dust is removed
20 and burning the fired pellet together with air.
The fired pellet may be produced into a spherical pellet of a size 3mm-
8mm by injecting very fine iron ore, bentonite, limestone, dolomite, and olivine
of a grain size 100㎛ or less together with water within a rotation type drum, be
8
preliminarily heated at 800℃-900℃, and be fired at 1,200℃-1,400℃.
In the iron ore reduction furnace or the gas purification filter type
reduction furnace, as an additive, CaO or CaCO3 may be injected.
Yet another embodiment of the present invention provides a method of
manufacturing molten iron including: producing reduced iron 5 by charging iron
ore to a reduction furnace and injecting a reduced gas; manufacturing molten
iron and a reduced gas that is injected into the reduction furnace by filling coal
and charging reduced iron that is discharged from the reduction furnace;
reducing sintered ore or a fired pellet by charging the sintered ore or the fired
10 pellet to a gas purification filter type reduction furnace and injecting a process
gas that is discharged from the reduction furnace; removing dust from the
reduced sintered ore or fired pellet; and charging the sintered ore or the fired
pellet in which dust is removed to an oxidation combustion furnace and burning
the sintered ore or the fired pellet together with air, wherein a portion of the
15 sintered ore or the fired pellet that is reduced and discharged in the gas
purification filter type reduction furnace is charged to the melting gas furnace.
The method may further include separating carbon dioxide by
condensing water vapor into water by exchanging a heat of a flue gas that is
discharged from the gas purification filter type reduction furnace and generating
20 electricity by rotating a steam turbine with generated steam.
The method may further include generating electricity by rotating a gas
turbine using air in which oxygen is deficient and that is discharged after
burning the sintered ore or the fired pellet in the oxidation combustion furnace.
9
The method may further include removing carbon dioxide by enabling a
flue gas that is discharged from the gas purification filter type reduction furnace
to pass through a carbon dioxide removal device and reinjecting the flue gas in
which carbon dioxide is removed into the gas purification filter type reduction
5 furnace.
The method may further include removing dust by enabling a process
gas that is discharged from the iron ore reduction furnace to pass through a gas
purification device.
The method may further include performing heat exchange in order to
10 heat air that is supplied to the oxidation combustion furnace.
【Advantageous Effects】
According to the present invention, carbon dioxide that is included in an
exhaust gas that is generated in a molten iron production process can be easily
removed, and power can be generated using a high temperature gas that is
15 generated in a process.
Further, according to the present invention, because a gas purification
filter type reduction furnace is provided, dust and a micro pollution material that
are generated in a process can be efficiently removed.
【Description of the Drawings】
20 FIG. 1 is a schematic diagram illustrating a molten iron manufacturing
apparatus according to a first exemplary embodiment of the present invention.
FIG. 2 is a graph illustrating a coal ratio, a molten iron production
amount according to an amount of carbon monoxide and hydrogen, and a
10
power generation amount.
FIG. 3 is a schematic diagram illustrating a molten iron manufacturing
apparatus according to a second exemplary embodiment of the present
invention.
FIG. 4 is a schematic diagram illustrating a molten 5 iron manufacturing
apparatus according to a third exemplary embodiment of the present invention.
【Mode for Invention】
Hereinafter, exemplary embodiments of the present invention will be
described in detail with reference to the attached drawings such that the present
10 invention can be easily put into practice by those skilled in the art. As those
skilled in the art would realize the described embodiments may be modified in
various different ways all without departing from the spirit or scope of the
present invention. Like reference numerals designate like elements throughout
the specification and the drawings.
15 FIG. 1 is a schematic diagram illustrating a molten iron manufacturing
apparatus according to a first exemplary embodiment of the present invention.
Referring to FIG. 1, a molten iron manufacturing apparatus 101
according to the present exemplary embodiment includes a melting gas furnace
10, an iron ore reduction furnace 20, a gas purification filter type reduction
20 furnace 30, a micro dust removal device 45, and an oxidation combustion
furnace 40.
The melting gas furnace 10 is a device that produces a reduced gas to
provide to the iron ore reduction furnace 20 and molten iron by filling coal and
11
by charging reduced iron that is reduced and discharged in the iron ore
reduction furnace 20. In the melting gas furnace 10, an oxygen supply line 14,
a pulverized coal supply line 13, a reduced iron supply line 61, and a coal
supply line 15 are connected.
Air or oxygen is injected into the melting gas furnace 5 10 through the
oxygen supply line 14, and pulverized coal is filled in the melting gas furnace 10
through the pulverized coal supply line 13. Further, coal is filled in the melting
gas furnace 10 through the coal supply line 15, and the reduced iron supply line
61 is disposed between the melting gas furnace 10 and the iron ore reduction
10 furnace 20 to charge reduced iron that is generated in the iron ore reduction
furnace 20 to the melting gas furnace 10.
Further, in the melting gas furnace 10, a first reduced sintered ore
supply line 64 that is connected to the gas purification filter type reduction
furnace 30 is installed, and sintered ore in which oxygen is deficient and that is
15 generated in the gas purification filter type reduction furnace 30 through the first
reduced sintered ore supply line 64 is supplied to the melting gas furnace 10.
Accordingly, reduced iron that is used in the melting gas furnace 10 is
formed with reduced iron that is supplied from the iron ore reduction furnace 20
and reduced sintered ore that is supplied from the gas purification filter type
20 reduction furnace 30. In this case, reduced sintered ore is formed with
reduced sintered ore or a reduced fired pellet.
The melting gas furnace 10 generates a high heat by combustion of coal
and pulverized coal and a reduced gas is generated within the melting gas
12
furnace 10. The reduced gas has a high heat of 1400°C - 1600°C and has
carbon monoxide and hydrogen as a main component.
The reduced gas having a high heat separates reduced iron into molten
iron and slag of other materials through reduction and melting that removes
oxygen by supplying a heat quantity into the melting 5 gas furnace 10 and
operating in reduced iron. For discharge of molten iron and slag, in the melting
gas furnace 10, a molten iron discharge line 16 is installed.
Coal may be supplied as coke or coal lump through a previous
treatment process, air may be injected into the melting gas furnace 10, but in
10 order to reduce carbon dioxide and to easily separate carbon dioxide from a
process gas, oxygen may be injected into the melting gas furnace 10.
The iron ore reduction furnace 20 is a device that produces reduced iron
by charging iron ore and injecting a reduced gas of a high temperature that is
supplied from the melting gas furnace 10. The iron ore reduction furnace 20
15 includes a first reduction furnace 21, a second reduction furnace 22, and a third
reduction furnace 23. In the present exemplary embodiment, it is illustrated
that the iron ore reduction furnace 20 includes three reduction furnaces, but the
present invention is not limited thereto and the iron ore reduction furnace 20
may include a plurality of reduction furnaces. The first reduction furnace 21
20 preliminarily heats iron ore, the second reduction furnace 22 preliminarily
reduces preliminarily heated iron ore, and the third reduction furnace 23 finally
reduces preliminarily reduced iron ore and converts the reduced iron ore to
reduced iron.
13
In the iron ore reduction furnace 20, an iron ore supply line 27 that
supplies iron ore to the iron ore reduction furnace 20 is installed. In this case,
the supplied iron ore is formed with ore of a natural state that is supplied from
the outside.
Further, a reduced gas supply line 12 that supplies 5 a reduced gas of a
high temperature that is generated in the melting gas furnace 10 to the iron ore
reduction furnace 20 is connected between the melting gas furnace 10 and the
iron ore reduction furnace 20.
A reduced gas of a high temperature that is supplied from the melting
10 gas furnace 10 is generated by combustion of air or oxygen, coal, and
pulverized coal and is a gas that is generated after reducing and melting iron
ore and includes carbon monoxide, carbon dioxide, hydrogen, water vapor, and
methane.
As shown in Reaction Equations 1 and 2, in the iron ore reduction
15 furnace 20, by reacting with reduced gas, iron ore is converted from a state
(Fe2O3, Fe3O4) including much oxygen to reduced iron, which is a state
(FeOx, Fe) including less oxygen. Here, X has a value between 0-1. Further,
as shown in Reaction Equation 3, a reduced gas is converted to carbon dioxide
and water vapor by a water-gas shift reaction. That is, a reduced gas including
20 carbon monoxide and hydrogen removes oxygen by operating in iron ore and is
converted to carbon dioxide and water vapor.
[Reaction Equation 1]
1/3 Fe2O3 + CO/H2 ----> 2/3 Fe + CO2/H2O
14
[Reaction Equation 2]
1/4 Fe3O4 + CO/H2 ----> 3/4 Fe + CO2/H2O
[Reaction Equation 3]
CO + H2O ----> CO2 + H2
As described above, reduced iron (FeOx, Fe) that 5 is generated in the
iron ore reduction furnace is supplied to the melting gas furnace 10 through the
reduced iron supply line 61.
The gas purification filter type reduction furnace 30 is a device that
reduces sintered ore by charging sintered ore and injecting a process gas that
10 is discharged after reducing iron ore in the iron ore reduction furnace 20.
Between the iron ore reduction furnace 20 and the gas purification filter type
reduction furnace 30, a process gas supply line 62 that is generated in the iron
ore reduction furnace 20 and that injects a process gas having carbon
monoxide and hydrogen as a main component into the gas purification filter
15 type reduction furnace 30 is connected.
An amount of a process gas that is discharged from the iron ore
reduction furnace 20 may be adjusted through an amount of air or oxygen, coal,
pulverized coal that are supplied to the melting gas furnace 10 and an iron ore
amount that is injected into the iron ore reduction furnace 20. Carbon
20 monoxide and hydrogen, which are a main component of a process gas may be
adjusted according to a coal and pulverized coal consumption amount.
As shown in FIG. 2, as a coal ratio is low and an amount of carbon
monoxide and hydrogen is less, it is advantageous in manufacturing molten
15
iron, and as a coal ratio is high and an amount of carbon monoxide and
hydrogen is much, it is advantageous in generating power.
For example, when a specific gravity of carbon monoxide and hydrogen
in a process gas is 30wt% or less, a molten iron production amount is increased
rather than a power generation amount, and when a specific 5 gravity of carbon
monoxide and hydrogen in a process gas is 60wt% or more, a power generation
amount is increased rather than a molten iron production amount. This is
because when a coal ratio is high and an amount of carbon monoxide and
hydrogen is much, an amount of a process gas relatively increases and thus
10 power generation efficiency increases.
The process gas supply line 62 is connected to a lower portion of the
gas purification filter type reduction furnace 30, and while rising upward from a
lower portion of the gas purification filter type reduction furnace 30, the process
gas reduces sintered ore. Further, sintered ore is injected into an upper
15 portion of the gas purification filter type reduction furnace 30.
Between the gas purification filter type reduction furnace 30 and the
oxidation combustion furnace 40, an oxidized sintered ore supply line 66 that
supplies oxidized sintered ore that is generated in the oxidation combustion
furnace 40 to the gas purification filter type reduction furnace 30 is connected to
20 an upper portion of the gas purification filter type reduction furnace 30.
In this case, carbon monoxide and hydrogen, which are a main
component of a process gas contact with sintered ore within the gas purification
filter type reduction furnace 30 to remove oxygen of the sintered ore and are
16
converted to carbon dioxide and steam to be discharged. Accordingly, in a
process gas, carbon dioxide may be easily separated and generated water may
be converted to steam.
A temperature of a process gas that is supplied to the gas purification
filter type reduction furnace 30 may be a high temperature 5 of 500°C or more,
and when the gas purification filter type reduction furnace 30 has a preliminary
reduction furnace, the process gas may maintain a high temperature of 300°C
or more. In a state in which sintered ore that is charged to the gas purification
filter type reduction furnace 30 includes much oxygen of a high temperature, the
10 sintered ore supplies a heat quantity to the gas purification filter type reduction
furnace 30 and contacts with a process gas to be reduced and is thus converted
to a state including less oxygen.
A process gas rises upward from a lower portion of the gas purification
filter type reduction furnace 30, and dust moves downward together with slowly
15 declining sintered ore. Accordingly, dust is separated from a process gas to be
discharged together with sintered ore. In this case, as a flow rate of a rising
process gas is slow, efficiency that removes dust from the process gas is
improved.
As described above, in the present exemplary embodiment, as an
20 oxygen providing particle of a medium circulation process, sintered ore is used,
and by injecting the sintered ore to an upper portion of the gas purification filter
type reduction furnace 30, dust that is included in a process gas rising in a
lower portion may be efficiently removed.
17
As iron ore of a natural state is fired and pulverized in a high
temperature, sintered ore is formed, and dust of a process gas may be removed
by reacting with the sintered ore. Sintered ore that is supplied to an upper
portion of the gas purification filter type reduction furnace 30 is formed with
Fe2O3 or Fe3O4 including much oxygen and has a temperature 5 of 700°C to
800°C or more. Such sintered ore supplies a heat to the gas purification filter
type reduction furnace 30, is reduced by reacting with carbon monoxide and
hydrogen of a process gas, and is thus converted to a FeO or Fe state that
includes less oxygen.
10 A reaction temperature of the gas purification filter type reduction
furnace 30 becomes 600°C to 700°C or more in consideration of a heat quantity
and a reduction property of sintered ore that is injected from the oxidation
combustion furnace 40, and a high reaction temperature is advantageous.
Here, sintered ore may be formed with ore that mixes iron ore powder,
15 limestone, and coal of a natural state and that heats, recrystallizes, or fires in a
half-melting state to 900°C-1400°C or 1100°C-1400°C and that is pulverized to
1mm-10 mm.
The pulverized sintered ore may be formed with ore that generally
contains FeO of 3-10wt% and entire Fe of 50wt% or more among ore.
20 However, a component of pulverized sintered ore may be variously set
according to a process condition and the present invention is not limited thereto.
Further, pulverized sintered ore may have high mechanical strength, low
reduction differentiation, and a high reduction property as ore in which a pore is
18
formed through reduction and oxidation reactions. By circulating from a Fe2O3
state to a FeO or Fe state in the gas purification filter type reduction furnace 30,
such sintered ore can improve reaction efficiency with carbon monoxide and
hydrogen.
As a size of sintered ore decreases, dust removal 5 efficiency of a process
gas is enhanced. As sintered ore that is used in the present invention, sintered
ore that is obtained from a sintering machine that is applied for a molten iron
production process may be used. Sintered ore having a grain size of 5mm-
50mm due to pulverization among sintered ore that is obtained from the
10 sintering machine may be used for a blast furnace and sintered ore having a
grain size smaller than 5mm-50mm may be used as an oxygen providing
particle of the gas purification filter type reduction furnace 30. A grain size of
sintered ore of the gas purification filter type reduction furnace 30 may be 10mm
or less, and preferably, a grain size of sintered ore may be 1mm-8mm.
15 The present exemplary embodiment illustrates that sintered ore is used
as a medium, which is an oxygen providing particle, but the present invention is
not limited thereto and a medium may be formed in a fired pellet form.
When a medium is formed with a fired pellet, the fired pellet includes
very fine iron ore of a grain size of 100μm or less or 60μm or less, bentonite as
20 a binder, and limestone, dolomite, and olivine as an adding material. Further, a
fired pellet is produced in a spherical pellet form having a size of about 3mm -
8mm by injecting very fine iron ore, a binder, and an adding material together
with water within a rotating drum. The spherical pellet that is produced with the
19
above method is preliminarily heated at 800°C-900°C and is fired at 1200°C-
1400°C to be produced.
The fired pellet has much more pores than that of sintered ore and
typically contains entire Fe of 50% or more, appropriately 60% or more. The
fired pellet may have hardness, a high reduction property, 5 and low reduction
differentiation like sintered ore. Further, when forming and firing a pellet to
contain micro coal powder among components of the pellet, the fired pellet is
more excellent than sintered ore from a pore development viewpoint.
A pellet between 8mm-20mm among pellets of 2mm-20mm that is
10 produced for manufacturing molten iron may be generally used in a blast
furnace process, and only a pellet of a small size of 2mm-8mm may be used as
an oxygen providing particle.
When a fired pellet is used as a medium, as an additive, CaO or CaCO3
may be injected into the iron ore reduction furnace 20 or the gas purification
15 filter type reduction furnace 30.
The gas purification filter type reduction furnace 30 may be formed in a
fixed layer reactor, fluidized bed reactor, and moving bed reactor form, but for
periodic replacement convenience of oxygen providing particles and
deactivation prevention by carbon deposition, it is preferable to form the gas
20 purification filter type reduction furnace 30 in a fluidized bed reactor or moving
bed reactor form.
When the gas purification filter type reduction furnace 30 is formed in a
fluidized bed form, an injected process gas is mixed with sintered ore within the
20
reactor to have uniform temperature distribution. Further, a process gas is
oxidized to be discharged to an upper portion of the gas purification filter type
reduction furnace 30, and while being reduced, sintered ore may be discharged
to a lower portion of the gas purification filter type reduction furnace 30 together
with dust within a process gas. The fluidized bed reactor is 5 coupled in series in
plural, and thus a process gas can be completely easily oxidized and dust
removal efficiency can be improved.
When the gas purification filter type reduction furnace 30 is formed in a
moving bed reactor form, a process gas is injected from an upper portion or a
10 side surface of the reactor, and the injected process gas may be completely
oxidized by continuous contact with a large amount of slowly declining sintered
ore. Further, in this case, while declining sintered ore is reduced, the declining
sintered ore may be discharged by together filtering dust within a process gas.
In the gas purification filter type reduction furnace 30, the first reduced
15 sintered ore supply line 64 that supplies a portion of the discharged reduced
sintered ore to the melting gas furnace 10 and a second reduced sintered ore
supply line 65 that supplies the remaining portions of reduced sintered ore to
the micro dust removal device 45 are installed. The remaining portions of
reduced sintered ore provide oxygen to carbon monoxide and hydrogen in the
20 gas purification filter type reduction furnace 30 and includes sintered ore of
discharged FeO or Fe, dust that is separated from a process gas, and
differentiated ore of sintered ore that is generated in a repeated medium
circulation type oxidation and reduction reaction.
21
Further, sintered ore that is supplied to the micro dust removal device 45
is mixed with sintered ore that is supplied from the outside in order to accelerate
activation thereof after dust is removed to be injected into the oxidation
combustion furnace 40.
In the gas purification filter type reduction furnace 5 30, a flue gas
discharge pipe 63 is connected, and a flue gas that is generated in the gas
purification filter type reduction furnace 30 is discharged through the flue gas
discharge pipe 63. In the flue gas discharge pipe 63, a heat exchanger may
be connected, and by converting water vapor within a flue gas to water by
10 exchanging a heat of a flue gas that is discharged from the gas purification filter
type reduction furnace, the heat exchanger separates carbon dioxide and
produces steam of a high temperature.
In this case, separated carbon dioxide may be stored at the
underground or may be separately used. Further, the flue gas discharge pipe
15 63 is connected to a generator 50, and the generator 50 includes a steam
turbine that generates electricity from steam that is generated by the heat
exchanger.
The micro dust removal device 45 is a device that moves dust from
reduced sintered ore that is discharged from the gas purification filter type
20 reduction furnace 30. The micro dust removal device 45 includes a vibration
screen device that is connected to the second reduced sintered ore supply line
65 and that removed micro dust. Further, the micro dust removal device 45
may include a previous dust removing unit that is installed before the vibration
22
screen device and that previously removes a portion of micro dust by injecting
air or nitrogen.
Further, the micro dust removal device 45 may include a magnet dust
removing unit, and the magnet dust removing unit removes deactivated oxygen
providing particles and dust by applying a magnetic field 5 to reduced sintered
ore. The deactivated oxygen providing particle and dust have magnetism, and
the magnet dust removing unit may pull and remove such oxygen providing
particles and dust. The oxygen providing particle and dust that are removed
by the magnet dust removing unit may be circulated to the melting gas furnace.
10 In the second reduced sintered ore supply line 65, a sintered ore supply
line 68 that supplies fresh (new) sintered ore to sintered ore that is discharged
from the gas purification filter type reduction furnace 30 is connected. In order
to supplement an amount of the reduced sintered ore that is supplied to the
melting gas furnace 10 and to accelerate activation thereof, the sintered ore
15 supply line 68 additionally supplies new sintered ore. The second reduced
sintered ore supply line 65 is connected to a lower portion of the oxidation
combustion furnace 40, and in a lower portion of the oxidation combustion
furnace 40, an air supply line 69 that supplies air is connected.
The oxidation combustion furnace 40 is a device that oxidizes sintered
20 ore by burning reduced sintered ore in which dust is removed together with
supplied air. The oxidation combustion furnace 40 generates a heat by
combustion and converts reduced sintered ore to oxidized sintered ore including
much oxygen.
23
Sintered ore in which oxygen is deficient supplies a heat to a reactor
while receiving the supply of oxygen in the air to be oxidized or transfers a heat
to sintered ore or air and is converted to oxidized sintered ore including much
oxygen of a high temperature and is recirculated to the gas purification filter
type reduction furnace 30. For this reason, the oxidized 5 sintered ore supply
line 66 that supplies sintered ore that is oxidized in the oxidation combustion
furnace 40 to the gas purification filter type reduction furnace 30 is installed
between the oxidation combustion furnace 40 and the gas purification filter type
reduction furnace 30.
10 Further, compressed air having a high pressure is injected through the
air supply line 69, the compressed air may be supplied in a room temperature
state, and the compressed air may exchange a heat with sintered ore that is
discharged from the gas purification filter type reduction furnace 30 and be
injected into the oxidation combustion furnace 40 in a high temperature state.
15 The injected air supplies oxygen for combustion to sintered ore and is
discharged in a state in which oxygen is deficient. In this case, a temperature
of the discharged air is 700°C-1200°C.
In order to efficiently transfer a heat that is generated in the oxidation
combustion furnace 40 to air, a flow rate of air is adjusted to be larger than that
20 of sintered ore. Further, the oxidation combustion furnace 40 may be formed
with a riser reactor, the riser reactor has an outlet in a lower portion thereof, and
sintered ore having a grain size of 10mm or 15mm or more may be removed in
a lower portion of the riser. Further, in an upper portion of the riser, a cyclone
24
is installed and thus by securing a wide space, rising oxidized sintered ore may
be easily separated in the air.
Further, the oxidation combustion furnace 40 may include a plurality of
reactors that are coupled in parallel, and a reactor pressure may maintain 30bar
in a room temperature for efficient power generation. In 5 this case, a pressure
is adjusted by injected compression air.
In the oxidation combustion furnace 40, a flue gas supply line 42 that
transfers air of a high temperature to a generator is installed, and the flue gas
supply line 42 is installed between the oxidation combustion furnace 40 and the
10 generator 50 to transfer a flue gas of a high temperature that is generated in the
oxidation combustion furnace 40 to the generator 50.
The generator 50 is a device that generates power using air of a high
temperature that is supplied through the flue gas supply line 42 and may be
formed with a gas turbine. Further, the generator 50 may be formed with a
15 complex electric generation system including a gas turbine and a steam turbine.
The gas turbine generates electricity with air in which oxygen is deficient and
that is discharged after supplying oxygen for combustion to new sintered ore
and reduced sintered ore in the oxidation combustion furnace 40, and the steam
turbine produces steam by exchanging a heat of air in which oxygen is deficient
20 and generates electricity using the produced steam.
As in the present exemplary embodiment, when a temperature of air that
is discharged from an oxidation combustion furnace is 700°C-1200°C, as a
volume thereof expands, an air pressure very increases and thus by driving a
25
turbine with a strong force, power generation efficiency can be improved.
Accordingly, the molten iron manufacturing apparatus 101 according to
the present exemplary embodiment can easily separate carbon dioxide that is
generated in a molten iron production process using medium circulation using
iron ore as a medium and can generate power by rotating a turbine 5 using air of
a high temperature that is generated in this process.
Hereinafter, a method of manufacturing molten iron according to the
present exemplary embodiment will be described.
A method of manufacturing molten iron according to the present
10 exemplary embodiment includes step of manufacturing reduced iron by
charging iron ore to a reduction furnace 20 and by injecting a reduced gas; step
of producing a reduced gas that is injected into the reduction furnace 20 and
molten iron by filling coal and charging reduced iron that is discharged from the
reduction furnace 20; step of reducing sintered ore or a fired pellet by charging
15 the sintered ore or the fired pellet to a gas purification filter type reduction
furnace 30 and injecting a process gas that is discharged from the reduction
furnace 20; step of removing dust from the reduced sintered ore or fired pellet;
and step of charging sintered ore or a fired pellet in which dust is removed to an
oxidation combustion furnace and burning the sintered ore or the fired pellet
20 together with air.
Further, in a method of manufacturing molten iron according to the
present exemplary embodiment, a portion of sintered ore or a fired pellet that is
discharged after being reduced in the gas purification filter type reduction
26
furnace 30 is charged to the melting gas furnace 10.
Further, a method of manufacturing molten iron according to the present
exemplary embodiment further includes step of separating carbon dioxide by
condensing water vapor into water by exchanging a heat of a flue gas that is
discharged from the gas purification filter type reduction 5 furnace 30 and
generating electricity by rotating a steam turbine with generated steam.
Further, a method of manufacturing molten iron according to the present
exemplary embodiment further includes step of generating electricity by rotating
a gas turbine using air in which oxygen is deficient and that is discharged after
10 burning sintered ore or a fired pellet in the oxidation combustion furnace 40.
FIG. 3 is a schematic diagram illustrating a molten iron manufacturing
apparatus according to a second exemplary embodiment of the present
invention.
Referring to FIG. 3, a molten iron manufacturing apparatus 102
15 according to a second exemplary embodiment of the present invention has the
same structure as that of a molten iron manufacturing apparatus according to
the first exemplary embodiment, except that a carbon dioxide removal device 70
is installed in a gas purification filter type reduction furnace 30 and thus a
description of the same structure will be omitted.
20 The carbon dioxide removal device 70 is connected to a flue gas
discharge pipe 63 of the gas purification filter type reduction furnace 30, and the
carbon dioxide removal device 70 is a device that removes carbon dioxide from
a flue gas that is discharged from the gas purification filter type reduction
27
furnace. The carbon dioxide removal device 70 absorbs carbon dioxide with a
method such as a carbon dioxide adsorbing method, carbon dioxide absorption
using amine or ammonia, and a carbon dioxide adsorbing method by removal.
Further, the carbon dioxide removal device 70 may include a water-gas
shift reactor and a hydrogen pressure swing 5 adsorption device.
A gas containing high concentration carbon dioxide that is absorbed in
the carbon dioxide removal device 70 may be stored, processed, or reused at
the underground. Further, in the carbon dioxide removal device 70, a
recirculation gas supply line 72 for reinjecting a gas purification filter type
10 reduction furnace flue gas in which carbon dioxide is removed into the gas
purification filter type reduction furnace 30 is installed, and the recirculation gas
supply line 72 removes carbon dioxide from a flue gas that is discharged from
the gas purification filter type reduction furnace 30 and again supplies a flue gas
having a remaining reduction force to the gas purification filter type reduction
15 furnace 30.
A gas purification filter type reduction furnace flue gas in which carbon
dioxide is removed is mixed together with a process gas that is supplied from an
iron ore reduction furnace 20 to be supplied to the gas purification filter type
reduction furnace 30, and when the gas purification filter type reduction furnace
20 flue gas in which carbon dioxide is removed is mixed, by improving a fraction of
carbon monoxide and hydrogen, power generation efficiency is improved.
Further, a condenser 71 that removes water that is included in a flue gas
may be further installed between the gas purification filter type reduction
28
furnace 30 and the carbon dioxide removal device 70. The condenser 71 is
connected to the flue gas discharge pipe 63 to separate water that is included in
a flue gas. The separated water is supplied to the generator 50 through a
water discharge pipe 74 that is connected to the condenser 71 and the
generator 50 to be used for production 5 of steam.
A method of manufacturing molten iron according to the present
exemplary embodiment includes step of removing carbon dioxide by enabling a
flue gas that is discharged from the gas purification filter type reduction furnace
30 to pass through the carbon dioxide removal device 70 and reinjecting the
10 flue gas in which carbon dioxide is removed into the gas purification filter type
reduction furnace 30 in addition to a method of manufacturing molten iron
according to the first exemplary embodiment.
FIG. 4 is a schematic diagram illustrating a molten iron manufacturing
apparatus according to a third exemplary embodiment of the present invention.
15 Referring to FIG. 4, a molten iron manufacturing apparatus 103
according to a third exemplary embodiment of the present invention has the
same structure as that of a molten iron manufacturing apparatus according to
the second exemplary embodiment, except for a gas purification device 81 that
is connected to a process gas supply line 62 and a heat exchange device 82
20 that is connected to a second reduced sintered ore supply line 65 and thus a
description of the same structure will be omitted.
The process gas supply line 62 supplies a process gas from an iron ore
reduction furnace 20 to a gas purification filter type reduction furnace 30, and
29
the gas purification device 81 removes dust that is included in a process gas.
The gas purification device 81 is installed at the front end of the gas purification
filter type reduction furnace 30 to remove dust from a process gas that is
discharged from the iron ore reduction furnace 20.
The gas purification device 81 may be formed with 5 a dry dust collection
device such as a cyclone, a ceramic candle filter, and a metal filter or a wet dust
collection device such as a scrubber. When the gas purification device 81 is
formed with a wet dust collection device, the gas purification device 81 is
formed in a structure that recovers a heat and that supplies a heat to a process
10 gas at the rear end of the wet dust collection device.
The heat exchange device 82 is installed between the gas purification
filter type reduction furnace 30 and a micro dust removal device 45 in the
second reduced sintered ore supply line 65, and in the heat exchange device
82, an air supply line 69 that supplies air to an oxidation combustion furnace 40
15 is connected.
The heat exchange device 82 is installed at the front end of the
oxidation combustion furnace 40 to heat air by inducing heat exchange of
sintered ore of a high temperature and air, and the heated air is supplied to the
oxidation combustion furnace 40 by the air supply line 69.
20 In this way, when the heat exchange device 82 is installed, by increasing
a pressure and a temperature of high temperature air that is discharged from
the oxidation combustion furnace 40 by supplying compression air of a high
temperature to the oxidation combustion furnace 40, power generation
30
efficiency can be improved.
A method of manufacturing molten iron according to the present
exemplary embodiment further includes step of removing dust by enabling a
process gas that is discharged from the iron ore reduction furnace 20 to pass
through the gas purification device 81 and step of exchanging 5 a heat in order to
heat air that is supplied to the oxidation combustion furnace 40 in addition to a
method of manufacturing molten iron according to the second exemplary
embodiment.
While this invention has been described in connection with what is
10 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】
A molten iron manufacturing apparatus, comprising:
an iron ore reduction furnace that produces reduced iron by charging
iron ore and injecting 5 a reduced gas;
a melting gas furnace that produces a reduced gas to provide to the iron
ore reduction furnace and molten iron by filling coal and by charging reduced
iron that is reduced and discharged in the iron ore reduction furnace;
a gas purification filter type reduction furnace that reduces sintered ore
10 by charging the sintered ore and injecting a process gas that is discharged after
reducing iron ore in the iron ore reduction furnace;
a micro dust removal device that removes dust from reduced sintered
ore that is reduced and discharged in the gas purification filter type reduction
furnace; and
15 an oxidation combustion furnace that oxidizes reduced sintered ore by
charging reduced sintered ore in which dust is removed and burning the
sintered ore together with air.
【Claim 2】
20 The molten iron manufacturing apparatus of claim 1, wherein in the
oxidation combustion furnace, an oxidized sintered ore supply line for supplying
oxidized sintered ore to the gas purification filter type reduction furnace is
installed.
32
【Claim 3】
The molten iron manufacturing apparatus of claim 1, wherein in the gas
purification filter type reduction furnace, a first reduced sintered ore supply line
that supplies a portion of the discharged reduced sintered ore 5 to the melting gas
furnace and a second reduced sintered ore supply line that supplies the
remaining portions of the reduced sintered ore to the micro dust removal device
are installed.
10 【Claim 4】
The molten iron manufacturing apparatus of claim 1, wherein the
sintered ore is ore that mixes iron ore powder, limestone, and coal of a natural
state and that is heated, recrystallized, or fired in a half-melting state in a range
of 900℃-1,400℃ and that is pulverized to 1mm-10mm.
15
【Claim 5】
The molten iron manufacturing apparatus of claim 3, wherein the
remaining portions of the reduced sintered ore comprise differentiated ore of
sintered ore of FeO or Fe that is discharged after providing oxygen to carbon
20 monoxide and hydrogen in the gas purification filter type reduction furnace, dust
that is separated from the process gas, and sintered ore that is generated in an
oxidation and reduction reaction of a repeated medium circulation method.
33
【Claim 6】
The molten iron manufacturing apparatus of claim 3, wherein in the
oxidation combustion furnace, in order to supplement an amount of the reduced
sintered ore that is supplied to the melting gas furnace and to accelerate
activation thereof, new sintered ore is additionally 5 supplied.
【Claim 7】
The molten iron manufacturing apparatus of claim 1, further comprising:
a heat exchange device that separates carbon dioxide and that
10 produces steam of a high temperature by converting water vapor within a flue
gas to water by exchanging a heat of the flue gas that is discharged from the
gas purification filter type reduction furnace; and
a steam turbine that generates electricity from steam that is generated
by the heat exchange device.
15
【Claim 8】
The molten iron manufacturing apparatus of claim 6, wherein a heat
quantity that is generated when sintered ore that is reduced in the oxidation
combustion furnace is fired with oxygen in the air is supplied to the new sintered
20 ore, air, and reduced sintered ore that is supplied from the micro dust removal
device.
【Claim 9】
34
The molten iron manufacturing apparatus of claim 8, further comprising
a gas turbine that generates electricity from air in which oxygen is deficient and
that is discharged after supplying oxygen for combustion to new sintered ore
and reduced sintered ore in the oxidation combustion furnace or a steam
turbine that produces steam by heat exchange of air 5 in which oxygen is
deficient and that generates electricity using the produced steam.
【Claim 10】
The molten iron manufacturing apparatus of claim 1, further comprising
10 a carbon dioxide removal device that is connected to the gas purification filter
type reduction furnace to remove carbon dioxide from a flue gas that is
discharged from the gas purification filter type reduction furnace.
【Claim 11】
15 The molten iron manufacturing apparatus of claim 10, wherein the flue
gas that is discharged from the gas purification filter type reduction furnace
produces steam by heat exchange, generates electricity by rotating a steam
turbine with the produced steam, removes water, and is supplied to the carbon
dioxide removal device.
20
【Claim 12】
The molten iron manufacturing apparatus of claim 10, wherein in the
carbon dioxide removal device, a recirculation gas supply line for reinjecting a
35
gas purification filter type reduction furnace flue gas in which carbon dioxide is
removed to the gas purification filter type reduction furnace is installed.
【Claim 13】
The molten iron manufacturing apparatus of claim 5 10, wherein the
carbon dioxide removal device comprises a water-gas shift reactor and a
hydrogen pressure swing adsorption device.
【Claim 14】
10 The molten iron manufacturing apparatus of claim 1, wherein a gas
purification device that removes dust from a process gas that is discharged from
the iron ore reduction furnace is installed at the front end of the gas purification
filter type reduction furnace.
15 【Claim 15】
The molten iron manufacturing apparatus of claim 14, wherein the gas
purification device is at least one that is selected from a cyclone, a ceramic
candle filter, a metal filter, and a scrubber.
20 【Claim 16】
The molten iron manufacturing apparatus of claim 14, wherein in the
oxidation combustion furnace, a heat exchange device for heating injected air is
installed at the front end of the oxidation combustion furnace.
36
【Claim 17】
A molten iron manufacturing apparatus, comprising:
an iron ore reduction furnace that produces reduced iron by charging
iron ore and injecting 5 a reduced gas;
a melting gas furnace that produces a reduced gas to provide to the iron
ore reduction furnace and molten iron by filling coal and by charging reduced
iron that is reduced and discharged in the iron ore reduction furnace;
a gas purification filter type reduction furnace that reduces a fired pellet
10 by charging the fired pellet and injecting a process gas that is discharged after
reducing iron ore in the iron ore reduction furnace;
a micro dust removal device that removes dust from the reduced fired
pellet that is reduced and discharged in the gas purification filter type reduction
furnace; and
15 an oxidation combustion furnace that oxidizes a reduced fired pellet by
charging a reduced fired pellet in which dust is removed and burning the fired
pellet together with air.
【Claim 18】
20 The molten iron manufacturing apparatus of claim 17, wherein the fired
pellet is produced into a spherical pellet of a size 3mm-8mm by injecting very
fine iron ore, bentonite, limestone, dolomite, and olivine of a grain size 100㎛ or
less together with water within a rotation type drum, is preliminarily heated at
37
800℃-900℃, and is fired at 1,200℃-1,400℃.
【Claim 19】
The molten iron manufacturing apparatus of claim 18, wherein in the
iron ore reduction furnace or the gas purification filter type 5 reduction furnace, as
an additive, CaO or CaCO3 is injected.
【Claim 20】
A method of manufacturing molten iron, the method comprising:
10 producing reduced iron by charging iron ore to a reduction furnace and
injecting a reduced gas;
manufacturing molten iron and a reduced gas that is injected into the
reduction furnace by filling coal and charging reduced iron that is discharged
from the reduction furnace;
15 reducing sintered ore or a fired pellet by charging the sintered ore or the
fired pellet to a gas purification filter type reduction furnace and injecting a
process gas that is discharged from the reduction furnace;
removing dust from the reduced sintered ore or fired pellet; and
charging the sintered ore or the fired pellet in which dust is removed to
20 an oxidation combustion furnace and burning the sintered ore or the fired pellet
together with air,
wherein a portion of the sintered ore or the fired pellet that is reduced
and discharged in the gas purification filter type reduction furnace is charged to
38
the melting gas furnace.
【Claim 21】
The method of claim 20, further comprising separating carbon dioxide by
condensing water vapor into water by exchanging a heat of 5 a flue gas that is
discharged from the gas purification filter type reduction furnace and generating
electricity by rotating a steam turbine with generated steam.
【Claim 22】
10 The method of claim 21, further comprising generating electricity by
rotating a gas turbine using air in which oxygen is deficient and that is
discharged after burning the sintered ore or the fired pellet in the oxidation
combustion furnace.
15 【Claim 23】
The method of claim 20, further comprising removing carbon dioxide by
enabling a flue gas that is discharged from the gas purification filter type
reduction furnace to pass through a carbon dioxide removal device and
reinjecting the flue gas in which carbon dioxide is removed into the gas
20 purification filter type reduction furnace.
【Claim 24】
The method of claim 23, further comprising removing dust by enabling a
39
process gas that is discharged from the iron ore reduction furnace to pass
through a gas purification device.
【Claim 25】
The method of claim 24, further comprising performing 5 heat exchange in
order to heat air that is supplied to the oxidation combustion furnace.