[Technical Field]
The present invention relates to an apparatus for supplying a reduction
gas into a fluidized bed reduction furnace, and more particularly, to an
apparatus for blowing a reduction gas into a fluidized bed reduction furnace that
suppresses sticking of a molten alkali chloride in a fluidized bed reduction
10 furnace of equipment for manufacturing molten iron.
[Background Art]
Equipment for manufacturing molten iron using FINEX is largely
composed of a fluidized bed reduction furnace that reduces iron ore and a
melting furnace that has an internal coal packed bed and melts the reduced iron
15 ore. A gas having strong reducing power mainly including carbon oxide (CO)
and hydrogen (H2) is produced by combustion of coal in the melting furnace, so
the gas is supplied as a reduction gas to the fluidized bed reduction furnace.
FINEX uses common coal and iron ore with particles removed in the
initial natural state, so it has the advantage of a low fuel cost and less
20 environment pollution in comparison to using a blast furnace.
FIG. 1 is a schematic diagram illustrating typical equipment for
manufacturing molten iron using FINEX, in which work at a high temperature
over about 1000 °C is done at the upper region in a melting furnace 10, so that
l
a large amount of dust is produced by thermal decomposition in the melting
furnace 10. Over 90 % of a reduction gas is collected from the melting furnace
10 by a hot cyclone 45 and put back into the melting furnace 10, but the noncollected
dust flows into fluidized bed reduction furnaces 21, 22, and 23. The
5 reduction gas flowing into the fluidized bed reduction furnaces 21, 22, and 23
includes dust, and the dust includes fine reduced iron and an alkali chloride
together with coal residue produced by thermal decomposition.
The high-temperature reduction gas is supplied to a flow layer 27
through a distribution plate 26 on the fluidized bed reduction furnaces 21, 22,
10 and 23 (see FIG. 2). Hundreds of nozzles 51 are disposed at regular intervals
on the distribution plate 51 and uniformly distribute the reduction gas to the flow
layer 27. While the reduction gas with dust passes through the nozzles 51, the
alkali chloride in a liquid state or a solid state makes the surfaces of the nozzles
51 rough by corroding them, thereby making a foreign substance easily stick to
15 the surfaces.
Further, since the alkali chloride is in a liquid state and has
adhesiveness at a high temperature, it sticks as a foreign substance on the
surfaces of the nozzles. The foreign substance on the nozzles 51 grows in the
process of manufacturing, and in the worst case, it clogs up the nozzles.
20 When some of the nozzles 51 are clogged, the flow of the reduction gas
concentrates at some regions, so return fines are accumulated and form a
stagnant layer in the region not supplied with the reduction gas. In this
configuration, a manometer 28 for measuring the difference in pressure
between the upper and lower regions of the fluidized bed reduction furnaces 21,
2
22, and 23 is provided, so it checks whether passages 29 of the distribution
plate 26 are clogged or not (see FIG. 2).
When the fluidized bed reduction furnaces 21, 22, and 23 cannot move
and reduce iron ore, there is inconvenience of having to stop the work of the
5 fluidized bed reduction furnaces 21, 22, and 23 and replace the nozzles with a
foreign substance thereon. Further, it may be possible to maintain the
temperature of the fluidized bed reduction furnaces 21, 22, and 23 under the
melting point of the alkali chloride in order to prevent the alkali chloride from
sticking in a liquid state on the nozzles, but in this case, the reduction rate of
10 ores decreases.
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 art.
15 [DISCLOSURE]
[Technical Problem]
The present invention has been made in an effort to allow for stable
work with a fluidized bed reduction furnace by preventing a molten alkali
chloride with high adhesiveness, which clogs up nozzles of a distribution plate
20 in the fluidized bed reduction furnace, from sticking on the surfaces of the
nozzles.
Further, the present invention has been made in an effort to provide an
apparatus for blowing a reduction gas into a fluidized bed reduction furnace
which can reduce a fuel cost by improving the reduction rate of ores, by
3
increasing the temperature of a reduction gas to be blown into the fluidized bed
reduction furnace.
[Technical Solution]
An exemplary embodiment of the present invention provides an
5 apparatus for blowing a reduction gas into a fluidized bed reduction furnace to
supply the reduction gas to a flow layer over a distribution plate having
passages. The apparatus may include: a flange that is attached to the top of
the distribution plate and has holes that communicate with the passages; and
nozzles that are made of graphite, with one end coupled to the flange and the
10 other end in close contact with the passage, to guide a reduction gas to the flow
layer.
The flange and the nozzles may be thread-fastened to each other, and
the nozzle may be tapered such that the diameter gradually decreases in the
inflow direction of the reduction gas.
15 The tapered angle of the nozzles may be 90° or less, and iron cores
may be implanted in the nozzles.
A protective projection may be formed on the bottom of the flange so
that the flange is fixed in close contact with the passage.
Another exemplary embodiment of the present invention provides an
20 apparatus for blowing a reduction gas into a fluidized bed reduction furnace to
supply the reduction gas to a flow layer over a distribution plate having
passages. The apparatus may include: a flange that is attached to the top of
the distribution plate and has holes that communicate with the passages; an
external nozzle that is formed integrally with the flange and tapered to be in
4
close contact with the passage; and an internal nozzle that is made of graphite
and attached on the inner side of the outer nozzle, and guides a reduction gas
to the flow layer.
[Advantageous Effects]
5 According to the present invention, a molten alkali chloride in a
reduction gas sticking to the surface of the nozzles on the distribution plate in a
fluidized bed reduction furnace is suppressed, so that operation of the fluidized
bed reduction furnace can be stable and maintained for a long time.
Further, the reduction rate of ore is increased by increasing the
10 temperature of a reduction gas, so a fuel cost can be reduced.
[Description of the Drawings]
FIG. 1 is a schematic diagram illustrating equipment for manufacturing
molten iron which has a common fluidized bed reduction furnace.
FIG. 2 is an enlarged view illustrating a fluidized bed reduction furnace
15 according to an exemplary embodiment of the present invention.
FIGS. 3 and 4 are enlarged views illustrating a nozzle according to a
first exemplary embodiment.
FIG. 5 is an enlarged view illustrating a nozzle according to a second
exemplary embodiment.
20 FIG. 6 is a plan view illustrating a flange according to an exemplary
embodiment of the present invention.
FIG. 7 is a cross-sectional view illustrating a distribution plate equipped
with the flange and the nozzle according to the first exemplary embodiment of
the present invention.
5
[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. As those skilled in
5 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. In order to make the description of the present invention clear, parts
not related to the description are not illustrated in the drawings and like
reference numerals are given to like members throughout the specification.
10 First, FIG. 1 is a schematic diagram illustrating equipment for
manufacturing molten iron which has a common fluidized bed reduction furnace,
FIG. 2 is an enlarged view illustrating one of fluidized bed reduction furnaces 21,
22, and 23 according to an exemplary embodiment of the present invention, and
FIGS. 3 to 5 are enlarged views illustrating nozzles according to exemplary
15 embodiments of the present invention.
Referring to FIG. 1, equipment for manufacturing molten iron using
FINEX includes a melting furnace 10 and fluidized bed reduction furnaces 21,
22, and 23 arranged in multiple stages. The fluidized bed reduction furnaces
21, 22, and 23 may be composed of three stages of a preheating furnace 21, a
20 pre-reduction furnace 22, and a final reduction furnace 23. The final reduction
furnace 23 is connected with the melting furnace 10 and a coal filling layer is
formed in the melting furnace 10.
Iron ore fines are sequentially moved to the preheating furnace 21, the
pre-reduction furnace 22, the final reduction furnace 23, and the melting furnace
6
10 along first to fourth ore pipes 31, 32, 33, and 34. A reduction gas in the
melting furnace 10 is discharged out of the equipment through a hot cyclone 45
and then through the final reduction furnace 23, the pre-reduction furnace 22,
and the preheating furnace 21 along first to fourth gas pipes 4 1 , 42, 43, and 44.
5 The iron ore fines is sent into the preheating furnace 21 through the first
ore pipe 31, and then preheated and forms a flow layer 27 over the distribution
plate 40 in the preheating furnace 21 by means of the reduction gas supplied
from the third gas pipe 43. The iron ore fines are thereafter sent into the prereduction
furnace 22 through the second ore pipe 32, and are then pre-reduced
10 and form a flow layer 27 over the distribution plate 50 in the pre-reduction
furnace 22 by means of the reduction gas supplied from the second gas pipe 42.
The pre-reduced iron ore fines are sent into the final furnace 23 through
the third ore pipe 33, and are then finally reduced and form a flow layer 27 over
a distribution plate 50 in the final reduction furnace 23 by means of the
15 reduction gas supplied from the first gas pipe 41. The finally reduced return
fines are sent into the melting furnace 10 through the fourth ore pipe 34 and
melted into molten iron in the coal packed bed. In this process, the reduction
gas in the preheating furnace 21 is discharged out of the equipment through the
fourth gas pipe 44.
20 Referring to FIG. 2, the flow layer 27 of iron ore fines is formed over the
distribution plate 50 composed of fireproof bricks. Hundreds of nozzles 51 for
taking a reduction gas are disposed at regular intervals on the distribution plate
50, so they uniformly distribute the reduction gas which flows inside through the
gas pipes 41, 42, and 43, to the flow layer 27. The distribution plate 26 has a
7
plurality of passages 29 through which the reduction gas flows, and a flange 50
having holes 56 that communicate with the passages 29 is fixed in close contact
on the top of the distribution plate 26.
Hereinafter, an apparatus for blowing a reduction gas according to a first
5 exemplary embodiment of the present invention is described.
In the nozzles 51 of the first exemplary embodiment of the present
invention, one end is coupled to the flange 50 and the other end is in close
contact with the passage to guide the reduction gas to the flow layer 27 and is
made of graphite. The passages 29 are formed in the shape of a cylinder and
10 communicate with the nozzles 51 to open the nozzles 51.
That is, the apparatus for blowing a reduction gas into a fluidized bed
reduction furnace according to the first exemplary embodiment of the present
invention includes the flange 50 formed in the shape of a plate, having the holes
56 that communicate with the passages 29, and attached to the top of the
15 distribution plate 26, and the nozzles 51 connected with the holes 56 and
exposed toward the bottom of the reduction furnace body 25 from the flange 50.
The flange 50 and the nozzle 51 are combined by a coupling portion 54, which
may be a threaded portion.
The nozzle 51 is formed such that the inner diameter and the outer
20 diameter gradually increase as they go away from the flange 50. That is, the
nozzle 51 is tapered such that the inner diameter and the outer diameter
gradually decrease as they go closer to the flange 50 from the lower end that
first comes in contact with the reduction gas. The tapered angle (a) of the
nozzle 51 has only to be smaller than 180°, but when it increases, friction
8
resistance of a reduction gas increases. Accordingly, in an exemplary
embodiment of the present invention, the tapered angle is set under 90°,
thereby increasing friction resistance. The angle is just an example in the
present invention, so it is not limited thereto. The nozzles 51 according to the
5 first exemplary embodiment of the present invention are about 10 mm thick (see
FIG. 3).
The reduction gas flowing into the reduction furnace body 25 includes
coal residue produced by thermal decomposition, and the dust includes fine
reduced iron and an alkali chloride. Dust in the reduction gas sticks as a
10 foreign substance on the inner wall of the nozzles 51 of the distribution plate 50
while passing through the nozzles 51. In particular, an alkali chloride such as
potassium chloride (KCI) or sodium chloride (NaCI) is in a liquid state and has
adhesiveness at a high temperature, so it can stick as a foreign substance on
the surface of the nozzles 51. In order to prevent this phenomenon, in an
15 exemplary embodiment of the present invention, the nozzles are made of
graphite that has low readability and wettability in reaction with an alkali
chloride to suppress a chloride sticking to the nozzles 51.
FIG. 3 illustrates a spiral coupling portion 54 for a nozzle 51 made of
graphite and a flange 50 made of SUS 310 so that the nozzle 51 and the flange
20 50 are easily combined. The flange 50 and the nozzle 51 are more firmly
combined at a high temperature by carburization.
A protective projection 58 is formed on the bottom of the flange 50 to be
inserted in the passage 29 of the distribution plate 26 so that the nozzle 51 can
be firmly combined with the distribution plate 26, and it prevents a foreign
9
substance such as dust from being accumulated in the space between the
nozzle 51 and the distribution plate 26. The protective projection 58 has
another function of preventing damage to the nozzle 51 due to twisting in
assembling/disassembling.
5 FIG. 4 illustrates a nozzle according to an exemplary embodiment of the
present invention with iron cores therein, in which iron cores 57 are implanted in
a nozzle 51 to increase resistance of the graphite portion against mechanical
shock. When a user removes a used nozzle 51 to repair the apparatus for
blowing a reduction gas according an exemplary embodiment of the present
10 invention, the nozzle 51 may be broken and clog up the passage 29 that is an
empty space between the nozzle and the distribution plate 26, so when the
nozzle 51 made of graphite cracks, the iron cores 57 in the nozzle 51 prevent
fragments of the nozzles due to cracks from coming off.
FIG. 6 is a plan view illustrating a flange according to an exemplary
15 embodiment of the present invention, and FIG. 7 is a view illustrating a nozzle
according to the first embodiment of the present invention disposed in the
passage of a distribution plate.
An apparatus for blowing a reduction gas into a fluidized bed reduction
furnace according to a second exemplary embodiment of the present invention
20 may include: a flange 50 that is formed in the shape of a plate, attached on the
top of the distribution plate 26, and has a hole 56 that communicates with the
passage 29; an external nozzle 51b that is formed integrally with the flange 50
and tapered such that the inner diameter increases as it goes away from the
hole 56 to come in close contact with the passage 29; and an internal nozzle
10
51a that is made of graphite and attached to the inner side of the external
nozzle 51b to guide a reduction gas to a flow layer 27.
Referring to FIG. 5, only the internal nozzle 51a according to an
exemplary embodiment of the present invention is made of graphite so that the
5 internal nozzle 51a made of graphite can be protected from physical shock
applied to the external nozzle 51b when being separated to replace the nozzle
51, whereas the internal nozzle 51a can protect the external nozzle 51b against
chemical corrosion.
In the second exemplary embodiment of the present invention, similar to
10 the first exemplary embodiment, the tapered angle (a) of the nozzle 51 is set
under 90° and iron cores 57 may be implanted in the internal nozzle 51a.
Further, according to an exemplary embodiment of the present invention,
coupling holes 53 are formed around the edge of the flange 50 so that the
flange can be fastened to or separated from the distribution plate by bolts and
15 the like.
While this invention has been described in connection with what is
presently considered to be practical exemplary embodiments, it is to be
understood that the invention is not limited to the disclosed embodiments, but,
on the contrary, is intended to cover various modifications and equivalent
20 arrangements included within the spirit and scope of the appended claims.

[CLAIMS]
[Claim 1]
An apparatus for blowing a reduction gas into a fluidized bed reduction
furnace to supply the reduction gas to a flow layer over a distribution plate
5 having passages, the apparatus comprising:
a flange that is attached to the top of the distribution plate and has holes
that communicate with the passages; and
nozzles that are made of graphite, with one end coupled to the flange
and the other end in close contact with the passage, to guide a reduction gas to
10 the flow layer.
[Claim 2]
The apparatus of claim 1, wherein the flange and the nozzles are
thread-fastened to each other.
15
[Claim 3]
The apparatus of claim 1, wherein the nozzles are tapered such that the
diameter gradually decreases in the inflow direction of the reduction gas.
20 [Claim 4]
The apparatus of claim 3, wherein the tapered angle of the nozzles is
90° or less.
12
[Claim 5]
The apparatus of claim 1, wherein iron cores are implanted in the
nozzles.
5 [Claim 6]
The apparatus of claim 1, wherein a protective projection is formed on
the bottom of the flange so that the flange is fixed in close contact with the
passage.
10 [Claim 7]
An apparatus for blowing a reduction gas into a fluidized bed reduction
furnace to supply the reduction gas to a flow layer over a distribution plate
having passages, the apparatus comprising:
a flange that is attached to the top of the distribution plate and has holes
15 that communicate with the passages;
an external nozzle that is formed integrally with the flange and tapered
to be in close contact with the passage; and
an internal nozzle that is made of graphite and attached on the inner
side of the outer nozzle, and guides a reduction gas to the flow layer.
20
[Claim 8]
The apparatus of claim 7, wherein the tapered angle is 90° or less.
13
[Claim 9]
The apparatus of claim 7, wherein iron cores are implanted in the
internal nozzle.