COAL BRIQUETTES AND METHOD OF PRODUCING THE SAME
CROSS-REFERENCE TO RELATED APPLICATION
5 This application claims priority to and the benefit of Korean Patent
Application No. 10-2014-0187542 filed in the Korean Intellectual Property Office
on December 23, 2014, the entire contents of which are incorporated herein by
reference.
l o BACKGROUND OF THE INVENTION
(a) Field of the Invention
The present invention relates to coal briquettes and a method of
producing the same. More particularly, the present invention relates to coal
briquettes and a method of producing the same in which a shape failure is
15 suppressed while having excellent strength.
(b) Description of the Related Art
In a reduced iron smelting process, iron ore is used in a reduction
furnace and a melter gasifier furnace that smelts reduced iron ore. When
smelting iron ore in the melter gasifier furnace, coal briquettes as a heat source
20 to smelt the iron ore are charged to the melter gasifier furnace. After reduced
iron is smelted in the melter gasifier furnace, the reduced iron is converted to
molten iron and slag and is discharged to the outside. The coal briquettes that
are charged to the melter gasifier furnace form a coal packed bed. Oxygen is
injected through a tuyere that is installed in the melter gasifier furnace such that
the coal packed bed is burned to generate a combustion gas. The combustion
gas is converted to a reduction gas of a high temperature while moving upward
through the coal packed bed. The reduction gas of a high temperature is
discharged to the outside of the melter gasifier furnace to be supplied to a
5 reduction furnace as a reduction gas.
After pulverized coal of crushed coal and a binder are mixed, coal
briquettes are produced via a shaping process of the mixed pulverized coal and
binder. That is, as the binder enables the pulverized coal to be agglomerated,
the pulverized coal is formed in a lump. As the pulverized coal is pressed in a
lo shaping process, coal briquettes having appropriate strength are produced.
The above information disclosed in this Ba&ground section is only for
enhancement of understanding of the background of the invention and therefore
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.
15 SUMMARY OF THE INVENTION
The present invention has been made in an effort to provide a method of
producing coal briquettes having advantages of being capable of preventing a
fraction and damage of the coal briquettes by suppressing a shape failure of the
coal briquettes. The present invention has been made in an effort to further
20 provide coal briquettes that are produced with the method of producing coal
briquettes.
An exemplary embodiment of the present invention provides a method
of producing coal briquettes that are charged in a dome portion of a melter
gasifier furnace to be quickly heated in a molten iron production apparatus,
including: charging reduced iron into the melter gasifier furnace, and providing
the reduced iron to a reduction furnace that is connected to the melter gasifier
furnace and that provides the reduced iron. The method includes providing
pulverized coal (SIO), producing a mixture by mixing the pulverized coal and a
5 binder (S20), and producing coal briquettes by shaping the mixture (S30).
When producing the mixture, the binder indudes molasses, caramel, and water.
In the producing of a mixture, the binder may indude molasses at 10
wt% to 75 wt%, caramel at 2 wt% to 20 wt%, and the remainder of water. An
amount of the molasses may be 50 wt% to 70 wt%, and an amount of the
lo caramel may be 5 wt% to 20 wt%.
In the producing of a mixture, the caramel may be produced from sugar
by caramelization.
In the producing of a mixture, an amount ratio of a binder to the mixture
may be 3 wt% to 12 wt%.
15 In the producing of a mixture, a hardener may be further mixed in the
mixture, and an amount thereof may be 1 wt% to 5 wt% of the mixture.
Another embodiment of the present invention provides coal briquettes
that are charged in a dome portion of a melter gasifier furnace to be quickly
heated in a molten iron production apparatus including: a melter gasifier furnace
20 in which reduced iron is charged; and a reduction furnace that is connected to
the melter gasifier furnace and that provides the reduced iron, wherein the coal
briquettes include pulverized coal and a binder, and wherein the binder includes
molasses, caramel, and water.
The binder may include molasses at 10wt % to 75 wt%, caramel at 2
wt% to 20 wt%, and the remainder of water.
An amount of the molasses may be 50 wt% to 70 wt%.
In a process of producing coal briquettes, a shape failure can be
suppressed. Therefore, a fraction of coal briquettes and damage of coal
5 briquettes can be prevented.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a flowchart illustrating a method of producing coal briquettes
according to an exemplary embodiment of the present invention.
FIG. 2 is a diagram illustrating a molten iron production apparatus using
lo coal briquettes that are produced with the method of FIG. 1.
FIG. 3 is a diagram illustrating another molten iron production apparatus
using coal briquettes that are produced with the method of FIG. 1.
DETAILED DESCRIPTION OF THE EMBODIMENTS
Terms such as first, second, and third are used for describing various
15 portions, components, areas, layers, andlor sections, but the terms are not
limited thereto. The terms are used only for distinguishing any portion,
component, area, layer, or section from other portions, components, areas,
layers, or sections. Therefore, a first portion, component, area, layer, or
section described hereinafter may be described as a second portion,
20 component, area, layer, or section within the scope without deviating from the
scope of the present invention.
Technical terms used here are used for only describing a specific
exemplary embodiment and are not intended to limit the present invention.
Singular forms used here include a plurality of forms unless phrases explicitly
represent an opposite meaning. A meaning of "comprising" used in a
specification embodies a specific characteristic, area, integer, step, operation,
element, and/or component and does not exclude the presence or addition of
another characteristic, area, integer, step, operation, element, andlor
5 component.
Unless otherwise defined, all terms including technical terms and
scientific terms used here have the same meaning as that which may be
generally understood by a person of common skill in the art. Further, terms
defined in a generally used dictionary have meanings corresponding to related
10 technical documents and presently disclosed contents, and are not to be
construed with ideal or overly official meanings unless so defined.
The present invention will be described more fully hereinafter with
reference to the accompanying drawings, in which exemplary embodiments of
the invention are shown. As those skilled in the art would realize, the
15 described embodiments may be modified in various different ways, all without
departing from the spirit or scope of the present invention.
FIG. 1 is a flowchart illustrating a method of producing coal briquettes
according to an exemplary embodiment of the present invention. The
flowchart of a method of producing coal briquettes of FIG. 1 illustrates the
20 present invention, and the present invention is not limited thereto. Therefore, a
method of producing coal briquettes may be variously changed.
As shown in FIG. 1, a method of producing coal briquettes includes a
step of providing pulverized coal (SIO), a step of producing a mixture by mixing
the pulverized coal and a binder (S20), and a step of producing coal briquettes
by shaping the mixture (S30). In addition, a method of produc~ng coal
briquettes may further include other steps as needed.
First, pulverized coal is provided (S10). Here, the pulverized coal is
obtained by crushing coal, and coal is generally classified into peat having
5 carbon powder at about 60 %, lignite and brown coal having carbon powder at
about 70 %, subbituminous coal having carbon powder at about 70 % to 80 %,
bituminous coal having carbon powder at about 80 % to 90 %, and anthracite
having carbon powder at 90 % or more according to a carbonization degree.
Here, a kind of used coal is not particularly limited, and the coal may be used as
lo a single coal kind or by mixing various kinds of coal. In order to reduce a
deviation of a quality, pulverized coal having a constant grain size may be used,
and as a detailed reference, pulverized coal having a grain size distribution in
which a grain size of 3 mm or less is 90 wt% to 100 wt% may be used.
Further, moisture of the pulverized coal may be adjusted to 3 wt% to 12
15 wt%. When an amount of moisture in the pulverized coal is adjusted to the
foregoing range, the moisture blocks pores of pulverized coal particles well.
Therefore, because a binder does not penetrate into the pulverized coal
particles but exists at the outside thereof, the binder couples pulverized coal
particles well, thereby efficiently improving hot strength and cold strength of coal
20 briquettes.
Thereafter, by mixing the pulverized coal and the binder, a mixture is
produced (S20). As the binder, one including molasses, caramel, and water
may be used. By appropriately mixing caramel with molasses as a binder, coal
briquettes are attached to a surface of a pair of rolls in a shaping process and
thus a phenomenon in which coal briquettes have a poor shape can be
prevented. Strength of coal briquettes can thereby be maintained.
In order for the binder to properly perform its function, adhesion and
cohesion should be performed well. Adhesion is an ability to effectively coat a
5 material to which a binder is attached and is a necessary function when mixing
pulverized coal and the binder. After the binder is coated, cohesion is an
ability to agglomerate the coated binder. This is a required function for step of
strongly coupling binders after the binder is coated to a material. A material
having a small molecular weight exhibits effective adhesion, while a material
lo having a large molecular weight exhibits effective cohesion. When shaping a
mixture of pulverized coal and a binder, while the pulverized coal and the binder
agglomerate upon shaping by a pair of rolls rotating in opposite directions, if the
pulverized coal does not adhere to a surface of the pair of rolls, a problem does
not occur in a shape of coal briquettes. That is, when the pulverized coal is
is attached to a surface of the pair of rolls, a shape of the coal briquettes is broken.
A shape failure of coal briquettes causes a fraction increase of the coal
briquettes and damage to the coal briquettes, and thus production efficiency of
the coal briquettes is deteriorated. When producing coal briquettes using
molasses as a binder, at the shaping step, the coal briquettes are partially
20 attached to a surface of the pair of rolls and thus a shape failure occurs.
Because molasses is strong in both adherence and cohesion, when
using only the molasses as a binder, coal briquettes are attached to a surface of
the pair of rolls that shape a mixture and thus a shape failure of the coal
briquettes frequently occurs. However, adherence of caramel corresponds to
that of molasses, but cohesion of caramel is weaker than that of molasses.
Therefore, when using molasses and caramel as a binder by mixing them, a
mixture is not well-attached to a surface of the pair of rolls and thus a shape
failure phenomenon of coal briquettes can be suppressed and strength of coal
5 briquettes can be improved. In caramel that is generally made of a low
molecular weight material (disaccharides, monosaccharides) and that is made
of only a material having a large molecular weight compared to molasses,
cohesion effectively occurs to reinforce a coupling ability between particles, and
adhesion ability is relatively deteriorated and thus attachment does not occur at
lo a surface of the pair of rolls.
The binder may include molasses at 10 wt% to 75wt %, caramel at 2
wt% to 20 wt%, and the remainder of water. When caramel of a very small
amount is included in the binder, a shape failure of coal briquettes may not be
enhanced. Further, when caramel of a very large amount is included in the
15 binder, strength of coal briquettes may be lowered. Therefore, an amount of
caramel that is included in the binder may be adjusted to the foregoing range.
Further, when water of a very small amount is included in the binder,
viscosity of the binder increases and thus it is difficult to transfer the binder in a
process. Further, when water of a very large amount is included in the binder,
20 the moisture content of all coal briquettes increases and thus strength thereof
may be deteriorated. Therefore, it is preferable to adjust a content Of water in
the foregoing composition range.
As a composition ratio of the binder, specifically, molasses at 20 wt% to
73 wt%, caramel of 3 wt% to 20 wt%, and the remainder of water may be used
in an entire binder weight. More specifically, the binder may include molasses
at 50 wt% to 70 wt%, caramel at 5 wt% to 20 wt%, and the remainder of water.
Caramel may be produced via a ring-opening reaction that opens a ring
of monosaccharides at a temperature of 20 "C or more. Further, caramel
5 decomposes polysaccharides into monosaccharides at a temperature of 50 "C
or more and becomes a polymer via a ring-opening reaction that opens a ring of
monosaccharides and via a condensation reaction. A reaction that produces
caramel from sugar in this way is referred to as caramelization. In order to
further accelerate caramelization, ammonia may be added. The
10 monosaccharides may be glucose, fructose, and xylose, and the
polysaccharides may be sucrose and lactose. When injecting and analyzing
caramel in a 10 mm cell using an ultraviolet (UV) spectrometer, a band of about
610 nm and an absorption rate of 0.15 to 2.0 were measured. Further, when a
concentration is 65 wt%, the viscosity of caramel is in a range of 10,000 cp to
15 50,000 cp.
in order to uniformly mix them, after molasses is first added to
pulverized coal, caramel may then be added. That is, when molasses and
caramel are mixed together, a reaction between molasses and caramel may
occur earlier than that in pulverized coal. Further, because it is preferable to
20 induce an adhesion phenomenon earlier than a cohesion phenomenon in
securing strength of coal briquettes, it is preferable to first add molasses to
pulverized coal.
An amount of a binder that is included in the mixture may be 3 wt% to
15 wt%. When an amount of the binder is too small, strength of coal briquettes
may be weakened. Further, when an amount of the binder is too large, a
problem of attachment may occur upon mixing pulverized coal and the binder.
Therefore, an amount of the binder is adjusted to the foregoing range.
Although not shown in FIG. 1, a hardener may be further mixed in the
5 mixture. An amount of the hardener in the mixture may be 1 wt% to 5 wt%.
As the hardener, CaO, Ca(OH)2, MgO, Mg(OH)2, Na20, NaOH, K20, and KOH
may be used. When an amount of the hardener is too small, the binder and
the hardener are not well coupled and thus strength of coal briquettes may not
be fully increased. Further, when an amount of the hardener is too large, ash
lo within coal briquettes increases and thus a heat necessary for smelting reduced
iron within a melter gasifier furnace may not fully occur. Therefore, an amount
of the hardener is adjusted to the foregoing range. Particularly, CaO of the
hardeners may further enhance strength of coal briquettes through a saccharate
reaction with molasses in the binder.
15 Finally, by shaping a mixture, coal briquettes are produced (S30).
Although not shown in FIG. 1, by charging a mixture between a pair of rolls
rotating in opposite directions, coal briquettes of a pocket form or a strip form
may be produced.
FIG. 2 is a diagram illustrating a molten iron production apparatus 100
20 using coal briquettes that are produced with the method of FIG. 1. A structure
of a molten iron production apparatus 100 of FIG. 2 illustrates the present
invention, and the present invention is not limited thereto. Therefore, the
molten iron production apparatus 100 of FIG. 2 may be changed to various
forms.
The molten iron production apparatus 100 of FIG. 2 includes a melter
gasifier furnace 10 and a reduction furnace 20. In addition, the molten iron
production apparatus 100 may include other apparatuses, as needed. In the
reduction furnace 20, iron ore is charged and reduced. After the iron ore that
5 is charged to the reduction furnace 20 is previously dried, the iron ore is
processed to reduced iron while passing through the reduction furnace 20.
The reduction furnace 20 is a packed bed type of reduction furnace, and
receives a reduction gas from the melter gasifier furnace 10 to form a packed
bed therein.
10 Because coal briquettes that are produced with a production method of
FIG. 1 are charged to the melter gasifier furnace 10, a coal packed bed is
formed within the melter gasifier fumace 10. In an upper portion of the melter
gasifier furnace 10, a dome portion 101 is formed. That is, a wide space is
formed, compared with other portions of the melter gasifier furnace 10 and at
15 the wide space, a reduction gas of a high temperature exists. Therefore, by a
reduction gas at a high temperature, coal briquettes that are charged to a dome
portion 101 may be easily divided. However, because coal briquettes that are
produced with a method of FIG. 1 have high strength and a small fraction and
damage, the coal briquettes are not divided in the dome portion of the melter
20 gasifier furnace 10 and descend to a lower portion of the melter gasifier furnace
10. By moving to the lower portion of the melter gasifier furnace 10, char that
is generated by a pyrolysis reaction of coal briquettes undergoes an exothermic
reaction with oxygen that is supplied through a tuyere 30. Therefore, the coal
briquettes may be used as a heat source that maintains the melter gasifier
furnace 10 at a high temperature. Because char provides air permeability, a
large amount of gas that is produced in a lower portion of the melter gasifier
furnace 10 and reduced iron that is supplied from the reduction furnace 20 may
more easily and uniformly pass through a coal packed bed within the melter
5 gasifier furnace 10.
In addition to the foregoing coal briquettes, lump coal ash or coke may
be charged to the melter gasifier furnace 10, as needed. The tuyere 30 is
installed at an outer wall of the melter gasifier furnace 10 to inject oxygen.
Oxygen is injected into a coal packed bed to form a firing zone. Coal
lo briquettes are burned in the firing zone to generate a reduction gas.
FIG. 3 is a diagram illustrating a molten iron production apparatus 200
using coal briquettes that are produced with the method of FIG. 1. A structure
of the molten iron production apparatus 200 of FIG. 3 illustrates the present
invention, and the present invention is not limited thereto. Therefore, the
15 molten iron production apparatus 200 of FIG. 3 may be changed to various
forms. Because a structure of the molten iron production apparatus 200 of
FIG. 3 is similar to a structure of the molten iron production apparatus 100 of
FIG. 2, like reference numerals designate like elements in the molten iron
production apparatus 200 of FIG. 3, and a detailed description thereof -&il be
20 omitted.
As shown in FIG. 3, the molten iron production apparatus 200 includes a
melter gasifier furnace 10, a reduction furnace 22, a reduced iron compression
apparatus 40, and a compression reduced iron reservoir 50. Here, the
compression reduced iron reservoir 50 may be omitted.
Produced coal briquettes are charged to the melter gasifier furnace 10.
Here, coal briquettes generate a reduction gas in the melter gasifier furnace 10,
and the generated reduction gas is supplied to a fluidized bed reduction furnace.
Iron ore fines are supplied to a plurality of reduction furnaces 22 each having a
5 fluidized bed and are reduced into reduced iron while being moved by a
reduction gas that is supplied from the melter gasifier furnace 10 to the
reduction furnaces 22. The reduced iron is compressed by the reduced iron
compression apparatus 40 and is stored in the compression reduced iron
reservoir 50. The compressed reduced iron is supplied from the compression
10 reduced iron reservoir 50 to the melter gasifier furnace 10 to be smelted in the
melter gasifier furnace 10. The coal briquettes are supplied to the melter
gasifier furnace 10 to be changed to char having air permeability and thus a
large amount of gas that is generated in a lower portion of the melter gasifier
furnace 10 and compressed reduced iron more easily and uniformly pass
15 through a coal packed bed within the melter gasifier furnace 10, thereby
producing good quality molten iron.
Hereinafter, the present invention will be described in detail through
experimental examples. However, such experimental examples merely
illustrate the present invention and the present invention is not limited thereto.
20 Caramel Produdion Ex~eriment
By dissolving a sugar mixture of sucrose, glucose, and fructose in water
at a concentration of 65 wt%, a 1 L sugar aqueous solution was produced. By
maintaining the 1 L sugar aqueous solution in an autoclave at a temperature of
a 150 "C for 5 hours, a caramel solution was produced.
Experimental Example 1
Pulverized coal having an average phase and a grain size of 3 mm or
less at 90 wt% or more was prepared. Quicklime of an amount of 3 wt% was
added to the prepared pulverized coal, and the pulverized coal and the
5 quicklime were mixed for 1 minute. Thereafter, molasses was added to the
pulverized coal, and the pulverized coal and the molasses were mixed for three
minutes. Subsequently, caramel was added to the pulverized coal, and the
caramel and the pulverized coal were mixed for three minutes. Molasses at 71
wt%, caramel at 4 wt%, and water at 25 wt% were each mixed in an entire
lo binder weight. An amount of the binder was 8 wt% of that of the pulverized
coal, and the remainder, except for the quicklime and the binder, was pulverized
coal. By compressing the mixture with a pair of shaping rolls, coal briquettes
of a pillow shape having a size of 64.5 mm X 25.4 mm X 19.1 mm were
produced.
15 Experimental Example 2
Molasses at 68 wt%, caramel at 7 wt%, and water at 25 wt% were each
mixed in an entire binder weight. The remaining experiment processes were
the same as those of Experimental Example 1.
Experimental Example 3
20 Molasses at 64 wt%, caramel at 11 wt%, and water at 25 wt% were
each mixed in an entire binder weight. The remaining experiment processes
were the same as those of Experimental Example 1.
Experimental Example 4
Molasses at 60 wt%, caramel at 15 wt%, and water at 25 wt% were
each mixed in an entire binder weight. The remaining experiment processes
were the same as those of Experimental Example 1.
Experimental Example 5
Molasses at 45 wt%, caramel at 30 wt%, and water at 25 wt% were
5 each mixed in an entire binder weight. The remaining experiment processes
were the same as those of Experimental Example 1.
Experimental Example 6
Molasses at 30 wt%, caramel at 45 wt%, and water at 25 wt% were
each mixed in an entire binder weight. The remaining experiment processes
lo were the same as those of Experimental Example 1.
Comparative Example 1
Caramel was not added, and as a binder, only molasses at 75 wt% and
water at 25 wt% were used. The remaining experiment processes were the
same as those of Experimental Example 1.
15 Comparative Example 2
Molasses were not added, and as a binder, only caramel at 75 wt% and
water at 25 wt% were used. The remaining experiment processes were the
same as those of Experimental Example 1.
Strength Evaluation Ex~eriment
20 The produced coal briquettes were dried for 1 hour at room temperature,
30 pieces of lower portions of coal briquettes were fixed and upper portions
thereof were pressed at a constant speed until the coal briquettes were broken,
and a maximum load thereof was measured and an average value thereof is
represented in Table 1.
Shape lnferioritv Rate Evaluation Experiment
Among 200 pieces of the produced coal briquettes, a case in which a
ball having a diameter of 1 cm or more was separated from coal briquettes was
evaluated as a shape failure, and a shape inferiority rate is represented in Table
5 1.
(Table 1)
Experimental
Example 1
Experimental
Example 2
Experimental
Example 3
Experimental
Example 4
Experimental
Example 5
Experimental
Example 6
Comparative
Example 1
Binder (wt%) Strength
(kg9
90
90
90
90
70
70
90
Molasses
71
68
64
60
45
30
75
Shape
inferiority rate
(%I
3
2.5
2
2
1
1
3
Caramel
4
7
11
15
30
45
0
Water
25
25
25
25
25
25
25 .
As represented in Table 1, it can be seen that coal briquettes that were
produced in Experimental Examples 1 to 6 had a low shape inferiority rate,
compared with coal briquettes that were produced in Comparative Example 1.
5 Further, it can be seen that coal briquettes that were produced in Experimental
Examples 1 to 6 had high strength, compared with coal briquettes that were
produced in Comparative Example 2. Further, coal briquettes that were
produced in Experimental Examples 2 to 4 had lower strength and shape
inferiority rate than those of coal briquettes that were produced in Comparative
lo Example 1.
A portion of coal briquettes that were produced according to
Comparative Example 1 was attached to a surface of a roll and thus the shape
of the coal briquettes was poorly produced. In contrast, in Experimental
Examples 1 to 6, when molasses and caramel as a binder were mixed together
15 and used, the coal briquettes were not well attached to a surface of the pair of
rolls and thus a shape failure of the coal briquettes was suppressed.
Therefore, it was determined that coal briquettes that were produced
according to Experimental Examples 1 to 6 can obtain excellent strength while
suppressing a shape failure in a production process.
20 Reverse Analvsis Ex~erimenot f Binder Com~onenot f Coal Briauettes
Coal briquettes at 100 g that were produced in Experimental Example 1
were crushed into small pieces. Thereafter, ethanol 500 ml was injected. By
Comparative
Example 2
0 75 25 65 0.5
decanting a liquid portion, the liquid portion was separated from the coal. By
filtering the separated liquid, a solid portion was separated. The liquid that was
included in the filtered solid portion was removed using a rotary evaporator, and
the remaining portions were produced into a 0.1 wt% aqueous solution. By
5 injecting and analyzing the remaining portions in a 10 mm cell using an UV
spectrometer, a band of about 610 nm and an absorption rate of 0.15 to 2.0
were measured. Thereby, it may be determined that caramel was mixed
therein. By calculating a ratio of sucrose of the concentrated liquid through a
high performance liquid chromatograph (HPLC), a composition thereof could be
l o determined.
While the present invention has been particularly shown and described
with reference to exemplary embodiments thereof, it will be understood by those
skilled in the art that various changes in form and details may be made therein
without departing from the spirit and scope of the invention as defined by the
15 appended claims. Therefore, it should be understood that the foregoing
exemplary embodiments are not limited but are illustrative.