Note: Descriptions are shown in the official language in which they were submitted.
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TUYERE FOR MANUFACTURING MOLTEN IRON AND METHOD
FOR INJECTING GAS USING THE SAME
Technical Field
The present invention relates to a tuyere for manufacturing molten
iron and a method for injecting gas using the same, and more particularly to
a tuyere that is capable of being prevented from being melted and
consequently damaged by charged materials in a melter-gasifier, and a
method for injecting gas using the same.
Background Art
Since a blast furnace method for manufacturing molten iron has
many problems such as an environmental pollution, a smelting reduction
process, which can replace the blast furnace method, has been researched.
In the smelting reduction process, raw coal is directly used as a fuel and a
reducing agent and an iron ore is directly used as an iron source. The iron
ore and the raw coal are charged into the melter-gasifier and then the iron
ore is melted to be manufactured into molten iron.
A tuyere is installed at a side portion of the melter-gasifier and
oxygen is injected into the melter-gasifier through the tuyere. The oxygen
injected into the melter-gasifier combusts a char bed formed in the melter-
gasifier. Therefore, the iron ore charged into the melter-gasifier is melted
by combustion heat, and thereby the molten iron is manufactured.
DISCLOSURE
Technical Problem
A tuyere that is capable of being prevented from being melted and
consequently damaged by using a sealing gas is provided. In addition, a
method for injecting gas using the above-described tuyere is provided.
Technical Solution
A tuyere according to an embodiment of the present invention is
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used for manufacturing molten iron. The tuyere includes i) an oxygen
injection opening that is configured to inject oxygen therethrough, and ii) a
sealing gas injection opening that is spaced apart from the oxygen injecting
opening and is configured to inject a sealing gas surrounding the oxygen.
The tuyere may further include i) a first end portion through which
the oxygen injection opening is exposed, and a
second end portion
that surrounds the first end portion. The sealing gas injection opening is
exposed through the second end portion. The first end portion may have a
concave groove.
The sealing gas injection opening may include a plurality of nozzles
through which the sealing gas is injected. The plurality of nozzles may be
spaced apart from each other at substantially equal intervals.
The sealing gas injection opening may further include i) a sealing gas
supply tube to which the sealing gas is supplied, and a sealing gas header
that is connected to the plurality of nozzles and the sealing gas supply tube
with each other. The sealing gas supply tube may be extended along one
direction. The sealing gas header may be formed to have a ring shape.
The tuyere according to an embodiment of the present invention may
further include an auxiliary fuel injection opening that is spaced apart from
the oxygen injection opening. An auxiliary fuel may be injected through the
auxiliary fuel injection opening. The oxygen injection opening may be
located between the sealing gas injection opening and the auxiliary fuel
injection opening.
One or more nozzles among the plurality of nozzles may be formed
to be extended to make an acute angle with a direction along which the
oxygen injection opening is extended. The acute angle may be in a range
from 5 degrees to 60 degrees. A cross-section of the nozzle cut along a
width direction of the tuyere may become larger while becoming closer to
the second end portion.
The oxygen injected through the oxygen injection opening and the
sealing gas injected through the sealing gas injection opening may make an
acute angle. The acute angle may be in a range of 5 degrees to 60 degrees.
The tuyere according to an embodiment of the present invention may
further include an auxiliary fuel injection opening that is spaced apart from
the oxygen injection opening. An auxiliary fuel is injected through the
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auxiliary fuel injection opening. The auxiliary fuel may be a fine
carbonaceous material or a hydrocarbon-containing gas.
The tuyere may further include i) a first end portion at which the
oxygen injection portion is formed, and a second end portion at which the
sealing gas injection opening is formed and surrounding the first end portion.
Therefore, the first end portion and the second end portion may be located at
the same plane.
The sealing gas may be at least one gas selected from a group of
compressed air, an oxygen containing gas mixture having a low oxygen
concentration and an inert gas. The inert gas may be nitrogen gas if the
sealing gas may include the inert gas. The tuyere may be installed at a side
portion of the melter-gasifier that manufactures molten iron such that the
sealing gas prevents charged materials in the melter-gasifier from reacting
with the oxygen at an end portion of the tuyere.
A method for injecting gas according to an embodiment of the
present invention includes i) injecting oxygen into the melter-gasifier
through the tuyere installed at the melter-gasifier, ii) injecting sealing gas
into the melter-gasifier through the tuyere, and
surrounding the oxygen
by the sealing gas while the sealing gas is injected into the melter-gasifier.
A method for injecting gas according to an embodiment of the
present invention may further include preventing the charged materials in
the melter-gasifier from reacting with the oxygen by the sealing gas. The
sealing gas may be injected to make an acute angle with the oxygen during
the injection of the sealing gas. The acute angle is in a range of 5 degrees
to
60 degrees.
A method for injecting gas according to an embodiment of the
present invention may further include injecting an auxiliary fuel into the
melter-gasifier through the tuyere. The auxiliary fuel may be a fine
carbonaceous material or a hydrocarbon-containing gas.
The sealing gas may be at least one gas selected from a group of
compressed air, an oxygen containing gas mixture having a low oxygen
concentration and an inert gas during the injection of the sealing gas. The
inert gas may be nitrogen gas if the sealing gas includes the inert gas.
Advantageous Effects
Since the tuyere can be prevented from being melted and
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consequently damaged, longevity of the tuyere can be significantly increased
and a process for manufacturing molten iron can be stably carried out.
DESCRIPTION OF DRAWINGS
FIG. 1 is a schematic perspective view of the tuyere according to a
first embodiment of the present invention.
FIG. 2 is a schematic cross-sectional view of the tuyere cut along the
line II-II of FIG. 1.
FIG. 3 is a schematic view showing an operating state of the tuyere of
FIG. 1.
FIG. 4 is a schematic cross-sectional view of the tuyere according to a
second embodiment of the present invention.
FIG. 5 is a schematic view showing a melter-gasifier installed with a
tuyere of FIG. 4.
FIG. 6 is a simulated photograph of a tuyere according to a first
exemplary example of the present invention.
FIG. 7 is a simulated photograph of a tuyere according to a second
exemplary example of the present invention.
BEST MODE
It will be understood that, although the terms first, second, third, etc.,
may be used herein to describe various elements, components, regions,
layers, and/or sections, these elements, components, regions, layers, and/or
sections should not be limited by these terms. These terms are only used to
distinguish one element, component, region, layer, or section from another
element, component, region, layer, or section. Thus, a first element,
component, region, layer, or section discussed below could be termed a
second element, component, region, layer, or section without departing from
the teachings of the present invention.
The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of the
invention. As used herein, the singular forms "a", "an", and "the" are
intended to include the plural forms as well, unless the context clearly
indicates otherwise. It will
be further understood that the terms
"comprises" and/or "comprising," or "includes" and/or "including", when
used in this specification, specify the presence of stated features, regions,
integers, steps, operations, elements, and/or components, but do not
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preclude the presence or addition of one or more other features, regions,
integers, steps, operations, elements, components, and/or groups thereof.
All terms including technical and scientific terms used herein have
the same meaning as commonly understood by one of ordinary skill in the
art to which this invention belongs. It will be further understood that terms
such as those defined in commonly used dictionaries should be interpreted
as having a meaning that is consistent with their meaning in the context of
the relevant art and the present disclosure, and will not be interpreted in an
idealized or overly formal sense unless expressly so defined herein.
The embodiments of the present invention will be explained in detail
with reference to FIGs. 1 to 5 below. These embodiments are merely to
illustrate the present invention and the present invention is not limited
thereto.
FIG. 1 is a schematic perspective view of a tuyere 10 according to a
first embodiment of the present invention. A structure of the tuyere 10
shown in FIG. 1 is merely to illustrate the present invention, and the present
invention is not limited thereto. Therefore, a structure of the tuyere 10 can
be modified in other forms.
The tuyere 10 shown in FIG. 1 is used for manufacturing molten iron.
Therefore, the tuyere 10 is installed at a side portion of a melter-gasifier
50
(shown in FIG. 5, the same hereinafter), thereby supplying oxygen to the
melter-gasifier 50. The oxygen is injected into the melter-gasifier 50 and
then combusts coal that has been charged into the melter-gasifier 50, and
thereby molten iron can be manufactured.
As shown in FIG. 1, an end portion 105 of the tuyere 10 includes a
first end portion 1051 and a second end portion 1053. The first end portion
1051 is formed with a concave groove. Therefore, the second end portion
1053 is protruded to be closer to the melter-gasifier 50 than the first end
portion 1051 when the tuyere 10 is installed at the melter-gasifier 50.
The second end portion 1053 surrounds the first end portion 1051.
A sealing gas injection opening 103 is exposed through the second end
portion 1053. A plurality of nozzles are formed in the second end portion
1053.
Meanwhile, as shown in FIG. 1, the tuyere 10 includes an oxygen
injection opening 101 and the sealing gas injection opening 103. The oxygen
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is injected through the oxygen injection opening 101. Here, the oxygen
includes not only pure oxygen but also a gas containing oxygen. The
oxygen injection opening 101 includes an oxygen supply line 1011 and the
oxygen is supplied therefrom.
The sealing gas injection opening 103 is located to be spaced apart
from the oxygen injection opening 101. The sealing gas is injected through
the sealing gas injection opening 103 while surrounding the oxygen gas.
Therefore, the end portion 105 can be sealed by the sealing gas. That is, the
end portion 105 can be prevented from being damaged to contact the
charged materials in the melter-gasifier 50 by using the sealing gas. An
inert gas atmosphere is formed to suppress the charged materials from being
recombusted or from generating an oxidization reaction even if the charged
materials contact oxygen.
The sealing gas injection opening 103 includes a sealing gas supply
line 1035 and a plurality of nozzles 1031. The sealing gas supply line 1035
supplies the sealing gas. The supplied sealing gas is injected into the
melter-gasifier 50 through the plurality of nozzles 1031. The plurality of
nozzles 1031 are arranged to be spaced apart from each other at substantially
equal intervals. Therefore, since the sealing gas can be uniformly injected
into the melter-gasifier 50, sealing efficiency can be optimized.
Here, the sealing gas may be compressed air, an oxygen containing
gas mixture having a low oxygen concentration, or an inert gas. If the
sealing gas is compressed air, the concentration of oxygen cannot be more
than 30 vol%. In addition, the sealing gas may be an inert gas itself or a gas
including the inert gas. For example, nitrogen and so on can be used as the
inert gas. Since a large amount of nitrogen exists in air, it is most suitable
to
be used. The sealing gas suppresses the oxygen from reacting with the
charged materials in the melter-gasifier 50 by surrounding the oxygen.
Therefore, the end portion 105 is prevented from being melted and
consequently damaged by high heat that is generated by reaction between
the charged materials and oxygen.
As shown in FIG. 1, the tuyere 10 is connected to end portion cooling
tubes 1071 and 1073 and body cooling tubes 1091 and 1093. Cooling water
cools the end portion 105 of the tuyere 10 while entering into and being
discharged from the end portion cooling tubes 1071 and 1073. The cooling
water enters into the end portion 105 through the cooling water inlet tube
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1071. After the cooling water cools the end portion 105, it is discharged
outside through the cooling water outlet tube 1073.
Meanwhile, more cooling water enters into the body of the tuyere 10
along a direction indicated by an arrow through the cooling water inlet tube
1091. After the cooling water cools the body of the tuyere 10, it is
discharged outside through the cooling water outlet tube 1093. A cooling
structure of the tuyere 10 will be explained in detail below with reference to
FIG. 2.
FIG. 2 schematically shows a cross-sectional structure of the tuyere 10
cut along a line II-II of FIG. 1. The end portion cooling tubes 1071 and 1073
and the body cooling tubes 1091 and 1093 of FIG. 1 are omitted in FIG. 2 for
convenience.
As shown in FIG. 2, the tuyere 10 includes the end portion cooling
chamber 107 and the body cooling chamber 109. The end portion cooling
tubes 1071 and 1073 (shown in FIG. 1) are connected to the end portion
cooling chamber 107 while the body cooling tubes 1091 and 1093 (shown in
FIG. 1) are connected to the body cooling chamber 109. The cooling
chambers are divided into the end portion cooling chamber 107 and the body
cooling chamber 109. Since the end portion cooling chamber 107 and the
body cooling chamber 109 are independently cooled, the body of the tuyere
10 can be continuously cooled even if the end portion 105 of the tuyere 10 is
damaged to expose the end portion cooling chamber 107. As a result, after
the cooling water flowing into the end portion cooling chamber 107 is
blocked, a process for manufacturing molten iron can be continuously
carried out.
As shown in FIG. 2, the sealing gas injection opening 103 includes the
nozzles 1031, a sealing gas header 1033, and the sealing gas supply tube 1035.
In addition, the sealing gas injection opening 103 may further include other
components.
As shown in FIG. 2, the nozzle 1031 is formed to make acute angles 01
and 02 with a direction (X-axis direction, indicated by a dotted line) along
which the oxygen injection opening 101 is extended. Therefore, the sealing
gas injected through the nozzle 1031 surrounds the oxygen injected through
the oxygen injection opening 101. Here, the acute angle 01 or 02 can be in a
range of 5 degrees to 60 degrees. If the acute angle 01. or 02 is less than 5
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degrees, a sealing effect cannot be expected since injection directions of the
oxygen and sealing gas are almost parallel. On the contrary, if the acute
angle 01 or 02 is over 60 degrees, the oxygen cannot be injected well toward
+X-axis direction since the sealing gas is injected to be very close to the
end
portion 105.
Meanwhile, as shown in FIG. 2, a cross-section 1033s that is formed
by cutting the nozzle 1031 along the X-axis direction, that is, a width
direction of the tuyere 10, is becomes larger as the nozzle 1031 becomes close
to the second end portion 1053. Therefore, the sealing effect can be
maximized since the sealing gas can be injected as a form of a curtain with a
predetermined width.
The sealing gas header 1033 connects the plurality of nozzles 1031
and the sealing gas supply tube 1035 with each other. The sealing gas
header 1033 is formed to have a ring shape. Therefore, the sealing gas
header 1033 receives the sealing gas supplied from the sealing gas supply
tube 1035 extended along one direction and distributes it as a ring shape.
The sealing gas that is dispersed as a ring shape in the sealing gas header
1033 can be uniformly injected outside through the plurality of nozzles 1031.
FIG. 3 schematically shows an operating state of the tuyere 10 of FIG.
1. As shown in FIG. 3, the tuyere 10 is installed at a side portion of the
melter-gasifier 50, thereby injecting oxygen into the melter-gasifier 50.
As shown in FIG. 3, the oxygen is injected through the oxygen
injection opening 101 while the sealing gas is injected to surround the oxygen
through the sealing gas injection opening 103. The oxygen is injected into
the melter-gasifier 50, thereby combusting the char bed and forming a
raceway.
Meanwhile, as indicated by an arrow, a backflow is formed by the
charged materials in the melter-gasifier 50. The charged materials in the
melter-gasifier 50 are not re-combusted or oxidized since they do not contact
the end portion 105 of the tuyere 10 and the oxygen by the sealing gas.
Here, the charged material can be non-combusted coal, slag, or molten iron.
The sealing gas prevents the charged materials from reacting with the
oxygen at the end portion 105. In addition, the sealing gas pulls the charged
materials while being collected in front of the oxygen injection opening 101
by a backflow characteristic of the charged materials and forming a non-
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combustion atmosphere. Therefore, the charged materials are not re-
combusted or oxidized in front of the oxygen injection opening 101.
As shown in FIG. 3, the oxygen and the sealing gas are injected into
the melter-gasifier 50 to form an acute angle 03 or 04. The acute angle 03 or
04 may be in a range of 5 degrees to 60 degrees. If the acute angle 03 or 04
is
less than 5 degrees, the oxygen and the sealing gas are injected to be in an
almost parallel manner with each other. Therefore, it is impossible to expect
a sealing effect. On the contrary, if the acute angle 03 or 04 is over 60
degrees, the oxygen may not be injected well from the oxygen injection
opening 161 due to the sealing gas.
FIG. 4 schematically shows a cross-sectional structure of a tuyere 20
according to a second embodiment of the present invention. Since the
structure of the tuyere of FIG. 4 is similar to that of the tuyere 10 of FIG.
2,
like elements are referred to by like reference numerals and detailed
descriptions thereof are omitted.
As shown in FIG. 4, the tuyere 20 further includes an auxiliary fuel
injection opening 201. The auxiliary fuel injection opening 201 is spaced
apart from the oxygen injection opening 101 and injects an auxiliary fuel.
The oxygen injection opening 101 is located between the auxiliary fuel
injection opening 201 and a sealing gas injection opening 203. Therefore, a
space for installing the auxiliary fuel injection opening 201 and the sealing
gas injection opening 203 together can be secured in the tuyere 20 by not
arranging the auxiliary fuel injection opening 201 and the sealing gas
injection opening 203 together.
For example, a fine carbonaceous material, a hydrocarbon-containing
gas, and so on can be used as the auxiliary fuel. The fine carbonaceous
material means a particle containing carbon with a grain size not more than
about 3mm. For example, the hydrocarbon-containing gas can be liquid
natural gas (LNG), liquid propane gas (LPG), coke oven gas (COG), and so
on. A fuel ratio can be reduced by injecting the auxiliary fuel into the
melter-gasifier 50 through the auxiliary fuel injection opening 201.
The auxiliary fuel is injected into the melter-gasifier and thereby
increases combustion heat. Therefore, an amount of coal charged from an
upper side of the melter-gasifier 50 can be reduced. In addition, the iron ore
can be reduced well since the auxiliary fuel generates a large amount of
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reducing gas. Furthermore, a state of a lower side of the melter-gasifier 50
may be unsuitable for manufacturing molten iron since the coal charged
from the upper side of the melter-gasifier 50 may be gasified to disappear
before reaching the lower side of the melter-gasifier 50. Therefore, the state
of the lower side of the melter-gasifier 50 can be improved by injecting the
auxiliary fuel into the lower side of the melter-gasifier 50.
Meanwhile, as shown in FIG. 4, an end portion 205 of the tuyere 20
includes a first end portion 2051 and a second end portion 2053. The
oxygen injection opening 101 is formed at the first end portion 2051 while the
sealing gas injection opening 203 is formed at the second end portion 2053.
Here, the first end portion 2051 and the second end portion 2053 are located
on the same plane P. The end portion 205 of the tuyere 20 can be sealed by
the sealing gas at the tuyere 20 with the above-described structure.
FIG. 5 schematically shows the melter-gasifier 50 at which the tuyere
20 of FIG. 4 is installed.
As shown in FIG. 5, iron ore and coal are charged into an upper
portion of the melter-gasifier 50, and thereby molten iron is manufactured in
the melter-gasifier 50 and is then discharged outside. Here, the iron ore
may be charged as reduced iron, while the coal may be charged as coal
briquettes. The coal briquettes are charged into the melter-gasifier 50 to
form a char bed (shown in FIG. 4, the same hereafter) and reducing gas is
generated to be discharged outside. The char bed is combusted by oxygen
that is injected through the tuyere 20 and combustion heat is then generated.
The reduced iron is melted by the combustion heat, thereby manufacturing
molten iron. The reducing gas discharged from the melter-gasifier 50 enters
into a fluidized-bed reduction reactor or a packed-bed reduction reactor,
thereby reducing the iron ore charged thereinto to manufacture reduced iron,
respectively.
As shown in FIG. 5, the oxygen, the sealing gas, and the auxiliary fuel
are charged into the melter-gasifier 50 through the tuyere 20. Therefore, the
combustion heat in the melter-gasifier 50 is increased, and thereby an
amount of coal charged from the upper portion of the melter-gasifier 50 can
be reduced.
The present invention will be explained in detail below with
reference to exemplary examples. The exemplary examples are merely to
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illustrate the present invention, and the present invention is not limited
thereto.
Exemplary Example 1
A flow of sealing gas injected through the tuyere with a structure
shown in FIG. 4 was simulated. The diameter of the oxygen injection
opening was 34mm, and nitrogen was used as the sealing gas. The flow
amount of the nitrogen was 32Nm3/hr and injection speed thereof was
40m/ s.
FIG. 6 shows the simulated flow of the sealing gas as lines.
As shown in FIG. 6, the sealing gas injected from the nozzle flowed
toward the first end portion while surrounding the oxygen that is injected at
a high temperature at a lower portion. That is, the end portion can be
effectively sealed since the sealing gas spirally flows.
Exemplary Example 2
A flow of sealing gas injected through the tuyere with a structure
shown in FIG. 4 was simulated. The flow amount of the nitrogen was
37Nm3/hr. A detailed description of the exemplary conditions is omitted
since remaining exemplary conditions are the same as those of Exemplary
Example 1.
FIG. 7 shows the simulated flow of the sealing gas as lines.
As shown in FIG. 7, the sealing gas injected from the nozzle flowed
toward the oxygen while surrounding the oxygen that is injected at a lower
portion. Therefore, the end portion can be effectively sealed.
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