[DESCRIPTION]
[Technical Field]
[0001] The present invention relates to a reduction furnace
reducing ore containing an iron oxide component and an
apparatus for manufacturing molten iron by melting reduced ore.
[Background Art]
[0002] FIG. 1 illustrates a typical reduction furnace reducing
ore containing an iron oxide component and an apparatus 1 for
manufacturing molten iron by melting reduced ore. As
illustrated in FIG. 1, the apparatus 1 includes a reduction
furnace 10 for reducing or preheating agglomerated ores, such
as pellets or lump ore, by injecting a reducing gas. A charge
material is introduced into the reduction furnace 10 through a
charge feeding port 11. The charge material reduced in the
reduction furnace 10 is discharged in a fixed amount by a
discharge screw 13 and the discharged charge material is
supplied to a melting furnace 20 through a vertical down pipe
14 and a tilt down pipe 16. A drop box 15 is included in the
vertical down pipe 14 and a nitrogen supply pipe (not shown)
is connected to the drop box 15 to inject nitrogen for cooling
into the vertical down pipe 14. The nitrogen for cooling may
decrease thermal shock applied to the discharge screw 13 by
gas flowing backwards to the reduction furnace 10 from the
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melting furnace 20.
[0003] In the melting furnace 20, reducing gas required for
the reduction of the charge material is prepared by the
gasification of coal and heat generated at this time is also
used to melt the charge material reduced and supplied from the
reduction furnace 10.
[0004] The reducing gas generated in the melting furnace 20 is
dust collected in a cyclone 22 and is then injected into the
reduction furnace 10 through a reducing gas intake port 17.
The inj ected reducing gas reduces the charge material while
passing through a packed bed 30 of the charge material in an
oxide form. The injected reducing gas may not be provided to
the center of the reduction furnace 10 due to the resistance
caused by the packed charge material and may mainly flow along
a wall portion thereof. The non-uniform distribution of the
reducing gas may cause severe unbalance of a reduction rate
for each position of the charge material and the unreduced
charge material at the center of the reduction furnace 10 may
be provided to the melting furnace 20 to break thermal balance
of the melting furnace 20, and thus , limitations, such as a
decrease in production, an increase in fuel cost, and a
decrease in an operating ratio, may occur. In particular, in
the case that a size of the typical reduction furnace 10 is
increased for the purpose of increasing the capacity thereof,
the non-uniform distribution of the reducing gas may be more
severe and it may be more difficult for the reducing gas to
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reach the center thereof when the size of the reduction
tI furnace 10 radial direction is increased in a radial direction.
[0005] Also, since pressure drop in the cyclone 22 may occur
in the case that the reducing gas generated in the melting
furnace 20 is inj ected into the reduction furnace 10 through
the cyclone 22, the reducing gas may flow backwards into the
reduction furnace 10 through the vertical down pipe 14 and the
discharge screw 13 having a relatively small pressure loss.
Therefore, in order to prevent this, installation of an
unreduced height h of the charge material is essentially
required for the purpose of generating a reduction in pressure
in the reducing gas flowing backwards into the reduction
furnace 10 through the discharge screw 13 and, as a result,
the height of a facility must be unnecessarily increased.
[Disclosure]
[Technical Problem]
[0006] An aspect of the present invention provides
improvements, such as an increase in production, a decrease in
fuel costs, an increase in an operating ratio, and operational
stability, by decreasing a thermal load of a melting furnace
when a charge material is supplied thereto by removing a nonuniform
distribution phenomenon of reducing gas, in which the
reducing gas supplied to the inside of a reduction furnace in
a reduction process is mainly flowing along a wall portion but
not introducing to the center of the reduction furnace thereof,
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to increase a reduction rate of the charge material and
uniformize reduction rates between particles of the charge
material.
[0007] Another aspect of the present invention provides an
increase in the capacity of a facility, able to be achieved by
simply increasing the size of a reduction furnace and a
deadman in a radial direction during the increase in the
capacity of the reduction furnace by allowing the reducing gas
to be uniformly distributed in the radial direction of the
reduction furnace.
[Technical Solution]
According to an aspect of the present invention, there is
provided a reduction furnace including: a charge feeding port
having a charge material introduced therethrough; and a
reducing gas intake port having reducing gas inj ected
therethrough, wherein the charge feeding port is formed in an
upper portion thereof and the reducing gas intake port is
installed in a bottom portion thereof.
[0008] The reducing gas intake port may be installed in a
bottom portion of a deadman disposed in a lower portion of the
reduction furnace.
[0009] A path connected to the reducing gas intake port may be
formed inside the deadman.
[0010] The path may be formed in plural to be symmetrical in a
radial direction.
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[0011] A vertical down pipe having the charge material reduced
by the reducing gas discharged therethrough may be filled with
the charge material in normal operating conditions.
[0012] A drop box may be installed in an end portion of the
vertical down pipe and a discharge screw discharging a fixed
amount of the charge material may be installed in the drop box.
[0013] The vertical down pipe has a predetermined vertical
length to generate a reduction in pressure in gas flowing
backwards into the reduction furnace through the vertical down
pipe.
an increase in the
the reducing gas may
be allowed to be uniformly distributed in a radial direction
of the reduction furnace, and thus,
[Advantageous Effects]
[0014] According to the present invention, since reducing gas
may be injected through a deadman disposed at the center of a
bottom portion of a reduction furnace, a reduction rate of a
charge material in the reduction furnace may increase,
reduction rates between particles of the charge material may
be uniformized, and a thermal load of a melting furnace may be
decreased during the charge material is supplied to the
melting furnace, and thus, an increase in production, a
decrease in fuel costs, an increase in an operating ratio, and
operational stability may be achieved.
[0015] Also, in the present invention,
capacity of a facility may be achieved by simply increasing
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the size of the reduction furnace and the deadman in the e radial direction thereof during the increase in the capacity
of the reduction furnace.
[0016] Also, since the position of a discharge screw, a charge
material supply device, may be changed from a lower end of the
reduction furnace to a portion of a drop box, differential
pressure in a vertical down pipe may be generated, and thus, a
back flow of high-pressure gas from the melting furnace into
the reduction furnace may be prevented.
[Description of Drawings]
[0017] The above and other aspects, features and other
advantages of the present invention will be more clearly
understood from the following detailed description taken in
conjunction with the accompanying drawings, in which:
[0018] FIG. 1 is a longitudinal sectional view illustrating a
typical reduction furnace reducing ore containing an iron
oxide component and an apparatus for manufacturing molten iron
by melting reduced ore; and
[0019] FIG. 2 is a longitudinal sectional view illustrating a
reduction furnace according to an embodiment of the present
invention.
[Best Mode]
[0020] Hereinafter, an embodiment of the present invention is
described in detail with reference to the accompanying
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drawings. e [0021] FIG. 2 is a longitudinal sectional view illustrating a
reduction furnace 100 according to an embodiment of the
present invention. Referring to FIG. 2, a charge feeding port
110 and a plurality of exhaust gas discharge ports 120 are
included in an upper portion of the reduction furnace 110. A
deadman 180 (or a deadwoman, hereinafter, both terms are used
interchangeably) is installed in a lower end of the inside of
the reduction furnace 100. The deadman 180 is installed to
prevent the degradation of the charge material due to the
accumulati ve load of the charge material itself or formation
of a stationary bed. A reducing gas intake port 170 is
installed in a bottom portion of the deadman 180 and a path is
formed inside the deadman 180 so as to allow the reducing gas
inj ected through the reducing gas intake port 170 to pass
therethrough. The reducing gas intake port 170 is formed in
the center of the reduction furnace 100 in a radial direction,
and the path inside the deadman 180 connected to the reducing
gas intake port 170 may be formed in plural to be symmetrical
in the radial direction.
[0022] A vertical down pipe 140 connected to the reduction
furnace 100 is installed in a lower portion of the reduction
furnace 100 and a drop box 150 is installed in an end portion
of the vertical down pipe 140. A discharge screw 130, an
attachable and detachable device for supplying a fixed amount
of the charge material, is installed in the drop box 150. A
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tilt down pipe 160 connected to a dome portion of a melting
tt furnace is installed in a lower portion of the drop box 150.
[0023] The charge material is introduced into the reduction
furnace 100 through the charge feeding port 110. The charge
material reduced in the reduction furnace 100 is transferred
to the vertical down pipe 140 to be discharged by the
discharge screw 130 formed in the end portion of the vertical
down pipe 140 in a fixed amount. The discharged charge
material is supplied to the melting furnace through the tilt
down pipe 160. Meanwhile, reducing gas reduces the charge
material and is then discharged through the exhaust gas
discharge ports 120.
[0024] Inner portions of the reduction furnace 100 and the
vertical down pipe 140 are filled with the charge material in
normal operating conditions.
[0025] According to the configuration of the foregoing
reduction furnace 100, reducing gas from the melting furnace
is allowed to be injected thereinto by the installation of the
reducing gas intake port 170 having the reducing gas passed
therethrough in the bottom portion of the deadman 180
installed at the lower end of the inside of the reduction
furnace, instead of a typical reducing gas intake port
disposed on an intermediate wall portion of the reduction
furnace, and thus, uniform distribution in the radial
gas, a reducing gas
direction may be induced from a
distribution phenomenon of the reducing
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typical non-uniform
utilization ratio and a reduction rate of the charge material
ta may be increased, and the reduction rate thereof may be
uniformized. Also, an increase in production, a decrease in
fuel costs, an increase in an operating ratio, and an increase
in operational stability may be achieved by reducing a thermal
load of the melting furnace when the charge material is
provided to the melting furnace. Further, since the reducing
gas may be uniformly distributed in the radial direction of
the reduction furnace, an increase in the capacity of facility
may be achieved by simply increasing the reduction furnace 100
and the deadman 180 in the radial direction thereof during the
increase in the capacity of the reduction furnace 100.
[0026] Also, since the discharge screw 130, a device for
supplying a fixed amount of the charge material, is installed
in a portion of the drop box 150 instead of the lower end of
the reduction furnace, a reduction in pressure in the vertical
down pipe 140 is generated, and thus, a back flow of highpressure
reducing gas in the melting furnace into the
reduction furnace 100 through the discharge screw 130 may be
prevented. That is, the back flow of high-pressure reducing
gas in the melting furnace disposed at a lower portion of the
tilt down pipe 160 into the reduction furnace 100 due to the
generation of differential pressure in the vertical down pipe
140 may be prevented. Typically, installation of an unreduced
height h of the charge material is essential for the purpose
of generating a reduction in pressure in the reducing gas in
10
order to prevent the back flow of the reducing gas through the
tt discharge screw 130. However, since the pressure loss may be
generated through the vertical down pipe 140 in the present
invention, the height of the reduction furnace 100 may be
reduced by as much as the unreduced height h of the charge
material illustrated in FIG. 1.
[0027] Further, nitrogen is typically injected into the
vertical down pipe 140 for the purpose of reducing thermal
shock applied to the discharge screw 130 by gas flowing
backwards from the melting furnace into the reduction furnace
100. However, since nitrogen injected into the vertical down
pipe 140 may not be required in the reduction furnace 100
according to the present invention, the amount of nitrogen
used may be reduced and operational costs may be reduced.
[0028] While the present invention has been shown and
described in connection with the exemplary embodiments, it
will be apparent to those skilled in the art that
modifications and variations can be made without departing
from the spirit and scope of the invention as defined by the
appended claims.

We Claim:
e (Claim 1]
A reduction furnace comprising:
a charge feeding port 110 having a charge material
introduced therethrough; and
a reducing gas intake port 170 having reducing gas
injected therethrough,
wherein the charge feeding port 110 is formed in an upper
portion thereof and the reducing gas intake port 170 is
installed in a bottom portion thereof.
(Claim 2]
The reduction furnace as claimed in claim 1, further
comprising a deadman 180 disposed in a lower portion thereof,
wherein the reducing gas intake port 170 is installed in
a bottom portion of the deadman 180.
(Claim 3]
The reduction furnace as claimed in claim 2, a path
connected to the reducing gas intake port 170 is formed inside
the deadman 180.
(Claim 4]
The reduction furnace as claimed in claim 3, the path is
formed in plural to be symmetrical in a radial direction.
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[Claim 5]
~ The reduction furnace as claimed in anyone of claims 1
to 4, further comprising a vertical down pipe 140 having the
charge material reduced by the reducing gas discharged
therethrough,
wherein inside of the vertical down pipe 140 is filled
with the charge material in normal operating conditions.
[Claim 6]
:>.
The reduct ion furnace as claimed in claim 5, wherein a
drop box 150 is installed in an end portion of the vertical
down pipe 140 and a discharge screw 130 discharging a fixed
amount of the charge material is installed in the drop box 150.
[Claim 7]
The reduction furnace as claimed in claim 6, wherein the
vertical down pipe 140 has a predetermined vertical length to
generate pressure drop in gas flowing backward into the
reduction furnace through the vertical down pipe 140.
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[Claim 8] e The reduction furnace substantially as herein described with
reference to forgoing examples and as illustrated in the
accompanying figures.