【DESCRIPTION】
【Invention Title】
METHOD FOR MANUFACTURING BRIQUETTE
【Technical Field】
The present invention relates to a method for manufacturing coa5 l
briquettes. More particularly, the present invention relates to a method for
manufacturing coal briquettes having excellent quality in a hot state.
(b) Description of the Related Art
In a smelting reduction iron-making method, a reducing furnace
10 reducing iron ores and a melter-gasifier melting reduced iron ores are used. In
the case of melting iron ores in the melter-gasifier, as a heat source to melt iron
ores, coal briquettes are charged into the melter-gasifier. Here, reduced iron
are melted in the melter-gasifier, transformed to molten iron and slag, and then
discharged outside. The coal briquettes charged into the melter-gasifier form a
15 coal-packed bed. After oxygen is injected through a tuyere installed at the
melter-gasifier, the coal-packed bed is combusted to generate combustion gas.
The combustion gas is transformed into a hot reducing gas while rising through
the coal-packed bed. The hot reducing gas is discharged outside the meltergasifier
to be provided to the reducing furnace as the reducing gas.
20 The coal briquettes are charged into the melter-gasifier as a heat source.
The coal charged into the melter-gasifier is transformed into a char by hot gas in
a dome portion to be used as a heat source for a melting reduced iron while
falling to the lower portion of the melter-gasifier. Accordingly, in order to melt
2
the reduced iron well, while the coal briquettes are not differentiated by hot gas
in the dome part of the melter-gasifier, the coal briquettes do not disappear
while falling to the lower portion of the melter-gasifier and thus it is required to
continuously keep the shape thereof.
【DISCLOSURE5 】
【Technical Problem】
A method for manufacturing coal briquettes having excellent quality in a
hot state is provided.
【Technical Solution】
10 In a method for manufacturing coal briquettes according to an
exemplary embodiment of the present invention, coal briquettes are charged
into a dome part of the melter-gasifier to be rapidly heated in an apparatus for
manufacturing molten iron including a melter-gasifier into which reduced irons
are charged, and a reducing furnace connected to the melter-gasifier and
15 providing the reduced iron. A method for manufacturing coal briquettes
according to an exemplary embodiment of the present invention includes i)
providing fine coal; ii) calcinating a carbon source; iii) providing a mixture
obtained by mixing the fine coal and the calcined carbon source; and iv)
providing coal briquettes by molding the mixture. In the providing of the
20 mixture, the amount of carbon source is more than 0wt% and 50wt% or less of
the mixture.
In the calcinating of the carbon source, the carbon source may be one
or more materials selected from a group consisting of petroleum coke,
3
anthracite coal, and brown coal. In the calcinating of the carbon source, the
carbon source may be one or more materials selected from a group consisting
of sub-bituminous coal, bituminous coal, and semi-anthracite coal.
In the providing of the mixture, the amount of carbon source may be
5wt% to 30wt%. The method may further include selecting a grain size of th5 e
carbon source, and in the providing of the mixture, the grain size of the carbon
source may be larger than 0 and is 3mm or less.
In the calcinating of the carbon source, a calcinating temperature of the
carbon source may be 700℃ to 1100℃. The calcinating temperature of the
10 carbon source is 800℃ to 1000℃.
In the calcinating of the carbon source, when the carbon source is
petroleum coke, the amount of petroleum coke in the mixture may be 10wt% to
50wt%. In the calcinating of the carbon source, when the carbon source is
anthracite coal, the amount of anthracite coal in the mixture may be 5wt% to
15 30wt%. In the calcinating of the carbon source, when the carbon source is
brown coal, the amount of brown coal in the mixture may be 5wt% to 30wt%.
【Advantageous Effects】
The coal briquettes may be manufactured with a low price while
improving hot strength of the coal briquettes by adding a relatively low-priced
20 carbon source such as petroleum coke, anthracite coal, and brown coal to the
coal briquettes. As a result, grain size and strength of a char may be
increased while the coal briquettes charged into the melter-gasifier are not
differentiated at a high temperature, thereby efficiently performing an operation.
4
【Description of the Drawings】
FIG. 1 is a schematic flowchart of a method for manufacturing coal
briquettes according to an exemplary embodiment of the present invention.
FIG. 2 is a schematic diagram of a manufacturing apparatus of molten
iron using the coal briquettes manufactured in FIG. 15 .
FIG. 3 is a schematic diagram of another manufacturing apparatus of
molten iron using the coal briquettes manufactured in FIG. 1.
【Mode for Invention】
Terms used herein such as first, second, and third are used to illustrate
10 various portions, components, regions, layers, and/or sections, but not limit
them. These terms are used to discriminate the portions, components, regions,
layers, or sections from the other portions, components, regions, layers or
sections. Therefore, the first portion, component, region, layer, or section as
described below may be the second portion, component, region, layer, or
15 section within the scope of the present invention.
It is to be understood that the terminology used herein is only for the
purpose of describing particular embodiments and is not intended to be limiting.
It must be noted that, as used in the specification and the appended claims, the
singular forms include plural references unless the context clearly dictates
20 otherwise. It will be further understood that the terms "comprises" and/or
"comprising," when used in this specification, specify the presence of stated
properties, regions, integers, steps, operations, elements, and/or components,
but do not preclude the presence or addition of one or more other properties,
regions, integers, steps, operations, elements, and/or components thereof.
5
Unless it is not mentioned, all terms including technical terms and
scientific terms used herein have the same meaning as the meaning generally
understood by a person with ordinary skill in the art to which the present
invention belongs. The terminologies that are defined previously are further
understood to have the meaning that coincides with relating technica5 l
documents and the contents that are disclosed currently, but are not to be
interpreted as the ideal or overly official meaning unless so defined.
The present invention will be described more fully hereinafter with
reference to the accompanying drawings, in which exemplary embodiments of
10 the invention are shown. 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.
FIG. 1 schematically illustrates a flowchart of a method for
manufacturing coal briquettes according to an exemplary embodiment of the
15 present invention. The flowchart of the method for manufacturing coal
briquettes of FIG. 1 is to just exemplify the present invention, and the present
invention is not limited thereto. Accordingly, the method for manufacturing coal
briquettes may be variously modified.
As illustrated in FIG. 1, the method for manufacturing coal briquettes
20 includes i) providing fine coal, ii) providing a carbon source obtained by calcined
petroleum coke, iii) providing a mixture by mixing the fine coal and the carbon
source, and iv) providing coal briquettes by molding the mixture. In addition, if
necessary, the method for manufacturing coal briquettes may further include
other processes.
6
First, in step S10, the fine coal is provided. The fine coal is used as
raw coal.
Next, in step S20, the carbon source is calcined. As the carbon source,
petroleum cokes, anthracite coal, or brown coal may be used. The petroleum
cokes are discharged as by-products in a variety of petroleum refinin5 g
processes. The petroleum coke includes coal ash of less than 1wt% and a
volatile matter of 10wt% to 12wt%. That is, since amounts of the coal ash and
the volatile matter included in the petroleum coke are small, the petroleum coke
has a calorific value which is higher than that of the raw coal by 10% or more.
10 Accordingly, in the case of using the petroleum coke, the coal ash of the coal
briquettes is reduced, and an amount of fixed carbon included in the coal
briquettes may be increased.
Generally, when the amount of coal ash included in coal is large,
contents of relatively combustible carbon and hydrogen decrease, and thus the
15 calorific value of coal decreases as well. If the amount of coal ash of the coal
charged into the melter-gasifier is large, most of the coal ash remains in the
char, and as result, the calorific value of the char is reduced and a calorific
value for dissolving the coal ash included in the char and discharging to slag is
additionally required. Since the usage amount of coal required for producing
20 molten iron increased due to the additional calorific value, it is not preferable
from the viewpoint of an increase in manufacturing cost. Accordingly, in order
to reduce the amount of coal ash included in the coal briquettes, the petroleum
coke having the low coal ash content is processed to be added. Char yield
that coal briquettes manufactured by using the method are transformed to the
7
char may be increased.
The petroleum coke is generally manufactured at a low temperature of
500℃ or less. Accordingly, if petroleum coke having a low heat-treatment
history is heat treated at a higher temperature than the low heat-treatment
history, the petroleum coke is thermally deformed while being contracted o5 r
thermally swollen. Therefore, in the case of manufacturing coal briquettes by
adding petroleum coke, the petroleum coke is deformed in the melter-gasifier at
1000℃ or more and thus the coal briquettes are differentiated to char having a
very small size.
10 Therefore, in step S20, green petroleum coke (G-PC) having a thermal
hysteresis at 500℃ or less is calcined at a high temperature. That is, the
green petroleum coke is calcined at a high temperature of 700℃ to 1100℃.
When a calcinating temperature of the green petroleum coke is very low, a
volatile matter discharging reaction of the green petroleum coke and
15 dehydrogenation in which hydrogen attached to a carbon skeleton is discharged
as a gas do not occur. Meanwhile, when the calcinating temperature of the
green petroleum coke is very high, a lot of energy is consumed due to hightemperature
treatment. Accordingly, the calcinating temperature of the green
petroleum coke is controlled in the aforementioned range, and thus the volatile
20 matter discharging reaction of the green petroleum coke and the
dehydrogenation are caused while reducing a heat-treatment time. Preferably,
the green petroleum coke is calcined at 800℃ to 1000℃.
When the petroleum coke is calcined, inert gas, air, or the like may be
8
used as atmospheric gas. More preferably, a combustible component of
petroleum coke is combusted by supplying air. The combustible component of
petroleum coke is combusted and thus the temperature of the petroleum coke
increases, and as a result, it is not required to supply extra energy requiring for
calcinating. In the case of measurement by an industrial analysis method 5 of
coal, the calcinating degree of the petroleum coke is sufficient if the volatile
matter is approximately less than 2%. Further, a grain size of calcined
petroleum coke is preferably more than 0 and 3mm or less. If the grain size of
the petroleum coke is very large, petroleum coke is not uniformly mixed with
10 fine coal and thus the quality of coal briquettes deteriorates. Accordingly, the
grain size of petroleum coke is controlled within the aforementioned range.
Meanwhile, anthracite coal or brown coal may be used as a carbon
source instead of the petroleum coke. The anthracite coal has the highest
degree of carbonization among different coals, and the volatile matter content
15 thereof is smallest. Accordingly, a discharging amount of the volatile matter is
relatively small while the anthracite coal is calcined, and as a result, a recovery
amount of a carbon source is large after calcinating the anthracite coal. The
quality in a hot state of coal briquettes may be improved by using brown coal
having the lowest degree of carbonization among different coals. In addition,
20 sub-bituminous coal, bituminous coal, or semi-anthracite coal may be used as a
carbon source.
Next, in step S30, a mixture in which fine coal and a carbon source are
mixed is provided. That is, the mixture in which the carbon source obtained by
calcinating petroleum coke, anthracite coal, or brown coal and the fine coal are
9
mixed is provided as a raw material. In this case, the amount of carbon source
in the mixture is 50wt% or less of the mixture. If a lot of the carbon source is
mixed with the mixture, manufacturing cost of the coal briquettes increases.
Accordingly, the amount of carbon source is controlled in the aforementioned
range. More preferably, the amount of carbon source may be 53wt% or less 5 of
the mixture.
Finally, in step S40, the mixture is molded to manufacture coal
briquettes. For example, after a binder such as molasses is mixed and added
to the mixture, the mixture is molded to manufacture coal briquettes. That is,
10 although not illustrated in FIG. 1, the mixture is compacted between a pair of
rolls rotating in opposite directions to each other to manufacture coal briquettes
in a pocket or strip shape. As a result, coal briquettes having excellent hot
strength and cold strength may be manufactured.
FIG. 2 schematically illustrates an apparatus for manufacturing molten
15 iron 100 using the coal briquettes manufactured in FIG. 1. A structure of the
apparatus for manufacturing molten iron 100 in FIG. 2 is just to exemplify the
present invention, and the present invention is not limited thereto. Accordingly,
the apparatus for manufacturing molten iron 100 in FIG. 2 may be modified in
various shapes.
20 The apparatus for manufacturing molten iron 100 in FIG. 2 includes a
melter-gasifier 10 and a reducing furnace 20. In addition, if necessary, other
devices may be included. Iron ore is charged into and reduced in the reducing
furnace 20. The iron ore charged into the reducing furnace 20 is dried in
advance and then prepared as reduced iron while passing through the reducing
10
furnace 20. The reducing furnace 20, as a coal-packed bed type of reducing
furnace, receives the reducing gas from the melter-gasifier 10 to form a coalpacked
bed in the reducing furnace 20.
Since the coal briquettes manufactured by the manufacturing method of
FIG. 1 are charged into the melter-gasifier 10, a coal-packed bed is formed i5 n
the melter-gasifier 10. A dome portion 101 is formed in the melter-gasifier 10.
That is, a wide space is formed as compared with another part of the meltergasifier
10, and hot reducing gas exists therein. Accordingly, the coal
briquettes charged into the dome portion 101 may be easily differentiated by the
10 hot reducing gas. That is, since the coal briquettes are charged into the top of
the melter-gasifier maintained at 1000℃, the coal briquettes are subjected to
drastic thermal impact. Accordingly, the coal briquettes may be differentiated
while moving to the lower portion of the melter-gasifier.
In order to overcome the differentiation condition, a process of improving
15 the strength of coal briquettes by using bitumen as a binder of the coal
briquettes is known. However, in the case of using bitumen as the binder,
there are problems in that manufacturing cost may be largely increased and the
coal briquettes are differentiated well in the melter-gasifier at 1000℃.
Accordingly, the coal briquettes need not be differentiated well in the melter20
gasifier by increasing the hot strength of the coal briquettes.
Thus, since the coal briquettes manufactured by using the method of
FIG. 1 have a high hot strength, the coal briquettes are not differentiated at the
dome portion of the melter-gasifier 10 and fall to the bottom of the meltergasifier
10. Char generated by a pyrolysis reaction of the coal briquettes
11
moves to the bottom of the melter-gasifier 10 to exothermic-react with oxygen
provided through the tuyere 101. As a result, the coal briquettes may be used
as a heat source which keeps the melter-gasifier 10 at a high temperature.
Meanwhile, since the char provides permeability, a large amount of gas
generated below the melter-gasifier 10 and reduced iron provided from th5 e
reducing furnace 20 may more easily and uniformly pass through the coalpacked
bed in the melter-gasifier 10.
In addition to the aforementioned coal briquettes, if necessary, lump
carbon ash or coke may be charged into the melter-gasifier 10. A tuyere 80 is
10 installed at an outer wall of the melter-gasifier 60 to inject oxygen. Oxygen is
injected to the coal-packed bed to form a combustion zone. The coal
briquettes are combusted in the combustion zone to generate reducing gas.
FIG. 3 schematically illustrates an apparatus for manufacturing molten
iron 200 using the coal briquettes manufactured in FIG. 1. A structure of the
15 apparatus for manufacturing molten iron 200 in FIG. 3 is just to exemplify the
present invention, and the present invention is not limited thereto. Accordingly,
the apparatus for manufacturing molten iron 200 in FIG. 3 may be modified in
various forms. Since the structure of the apparatus for manufacturing molten
iron 200 in FIG. 3 is similar to the structure of the apparatus for manufacturing
20 molten iron 100 in FIG. 2, like reference numerals are used in like parts, and the
detailed description is omitted.
As illustrated in FIG. 3, the apparatus for manufacturing molten iron 200
includes a melter-gasifier 10, a reducing furnace 22, a device for manufacturing
compacted irons 40, and a compacted irons storage bin 50. Here, the
12
compacted irons storage bin 50 may be omitted.
The manufactured coal briquettes are charged into the melting gasifier
10. Here, the coal briquettes generate reducing gas in the melter-gasifier 10
and the generated reducing gas is provided to a fluidized-bed reducing furnace.
Fine iron ore is provided to a plurality of fluidized-bed reducing furnaces 22, an5 d
is manufactured to reduced iron while being fluidized by reducing gas provided
to the reducing furnaces 22 from the melter-gasifier 10. The reduced iron is
compacted by the device for manufacturing compacted irons 40 and stored in
the compacted irons storage bin 50. The compacted reduced iron is provided
10 from the compacted irons storage bin 50 to the melter-gasifier 10 to be melted
in the melter-gasifier 10. Since the coal briquettes are provided to the meltergasifier
10 to be transformed to char having permeability, a large amount of gas
generated below the melter-gasifier 10 and the compacted reduced iron more
easily and uniformly pass through the coal-packed bed in the melter-gasifier 10
15 to manufacture molten iron with good quality.
Hereinafter, the present invention will be described in more detail
through experimental examples. experimental examples are just to exemplify
the present invention, and the present invention is not limited thereto.
Experimental Example
20 Coal briquettes for adding and charging petroleum coke, anthracite coal,
and brown coal into the melter-gasifier were manufactured. Molasses was
used as a binder during manufacture of the coal briquettes. In order to
evaluate the quality of the manufactured coal briquettes, 1000g of coal
briquettes were charged into a reaction tube maintained at 1000℃, heat-treated
13
at 10 rotations per minute, that is, a rotational speed of 10 rpm for 60 minutes to
obtain char, and the obtained char was distributed. A hot strength index of
coal briquettes was evaluated by representing a percentage of a weight of char
with 10 mm or more as a sieve with respect to a weight of the entire char.
Petroleum coke adding experimen5 t
Molasses of 8.5 equivalents was mixed with fine coal with respect to a
total amount of 100 equivalents of calcined petroleum coke to manufacture coal
briquettes. Main properties of petroleum coke are listed in the following Table
1.
10 (Table 1)
Technical analysis (%) Calorific value
Coal ash Volatile matter Fixed carbon (Kcal/kg)
0.5 10.9 88.6 8500
Experimental Example 1
Non-calcined petroleum coke having properties of Table 1 or 10% of the
petroleum coke calcined at 800℃ was added to coal A including 36% of a
15 volatile matter to manufacture coal briquettes for charging into the meltergasifier.
Properties and quality in a hot state of coal briquettes are listed in the
following Table 2. The calcined petroleum coke is represented as calcined
petroleum coke (C-PC).
Since the calcined petroleum coke exists in a state where the volatile
20 matter is removed, in the case of adding the calcined petroleum coke, the
amount of fixed carbon added in the coal briquettes increased. Meanwhile, the
14
hot strength index of the coal briquettes was largely improved to 54.3% and to
be much larger than the hot strength index of 12.3% of coal briquettes of
Comparative Example 1 and the hot strength index of 8.7 % of coal briquettes
of Comparative Example 2, and thus a large grain size of char may be
generated. Accordingly, when the calcined petroleum coke is added to th5 e
coal briquettes, during hot heat treatment, the petroleum coke is not physically
changed, and thus the coal briquettes may generate a large grain size of char.
Experimental Example 2
An amount of calcined petroleum coke mixed in the coal briquettes was
10 controlled to 30wt%. The rest processes for manufacturing coal briquettes are
the same as those in the aforementioned Experimental Example 1.
As listed in Table 2, since an adding amount of calcined petroleum coke
increased, the amount of fixed carbon increased while the amount of coal ash
included in the coal briquettes was further reduced. Further, char yield largely
15 increased, and the hot strength index which was differentiation resistance
capacity at a high temperature of the coal briquettes largely increased.
Comparative Example 1
A molasses binder was mixed with coal A to manufacture coal briquettes.
In this case, since the volatile matter content of the coal briquettes was high at
20 approximately 40%, the amount of fixed carbon of the coal briquettes was very
low as 50.1%. Further, yield of char obtained by heat-treating the coal
briquettes at 1000℃ for 60 minutes was low at 62.4%.
Comparative Example 2
In order to reduce coal ash of coal briquettes and improve char yield, 10
15
wt% of fine green petroleum coke (G-PC) was added to coal A to manufacture
coal briquettes. In this case, the coal ash of the coal briquettes was slightly
reduced and the amount of fixed carbon increased. Further, char yield
increased to 64.5 % and coal ash of char was rather reduced. However, in
spite of improved physical properties of the coal briquettes, the hot streng5 th
index of the coal briquettes was reduced to 8.7 %
The reason is that petroleum coke without coking force added for
reducing the coal ash did not contribute to binding of the coal briquettes
according to a thermal change in a heating process at a high temperature and
10 was differentiated to small particles.
Comparative Example 3
50wt% of coal A and 50wt% of calcined petroleum coke were mixed with
each other to manufacture coal briquettes. Since the rest of experimental
processes are the same as those of the aforementioned Experimental Example
15 2, the detailed description is omitted.
In this case, the amount of coal ash of the coal briquettes was reduced,
the amount of fixed carbon increased, and char yield increased, but the hot
strength index of the coal briquettes was rather reduced. When the coal
briquettes are rapidly heated, particles of a powder are fused to each other to
20 form lump char. However, due to a characteristic of coal A which is a raw coal
having low coking force, when an adding amount of calcined petroleum coke
which is a solid powder is high at 50% or more, a large grain size of char may
not be obtained. That is, since the petroleum coke has a solid powder shape
without coking force, there is a limit to the adding amount during manufacture of
16
the coal briquettes.
(Table 2)
Experimental
Example
Raw material
mixing ratio (%)
Technical analysis
of coal briquettes
(%)
Technical
analysis of
char (%)
Char
yield
(%)
Hot
strength
index
(+10
mm, %)
Coal
A
GPC
C-PC Coal
ash
Fixed carbon
Coal
ash
Fixed
carbon
Experimental
Example 1
90 10
10.1 53.7 15.0 82.9 65.4 54.3
Experimental
Example 2
70
30 9.6 57.2 69.5 59.5
Comparative
Example 1
100
10.3 50.1 16.3 81.7 62.4 12.3
Comparative
Example 2
90 10
10.1 52.5 15.0 82.7 64.5 8.7
Comparative
Example 3
50
50 8.9 63.5 73.5 21.5
Calcined anthracite coal adding experiment
Coal briquettes were manufactured by using anthracite coal instead 5 of
petroleum coke. The anthracite coal has the highest degree of carbonization
among different kinds of coal. The coal briquettes were manufactured by
mixing calcined anthracite coal and non-anthracite coal with fine coal.
Experimental Example 3
17
Coal briquettes were manufactured by mixing 5wt% of anthracite coal
calcined at 800℃ and 95wt% of coal A. The rest of experimental processes
were the same as those of the aforementioned Experimental Example 1.
Properties and quality in a hot state of the coal briquettes manufactured
according to Experimental Example 3 are listed in the following Table 35 .
As listed in Table 3, the coal ash content of the coal briquettes was
slightly increased by adding calcined anthracite coal, but the fixed carbon
content of the coal briquettes was also increased. The reason is that the coal
ash content included in the added anthracite coal is high and thus the volatile
10 matter of the coal briquettes is reduced in a calcinating process. When the
amount of fixed carbon of the coal briquettes increased while the amount of
volatile matter of the coal briquettes is reduced, probability that the coal
briquettes are transformed to char in the melter-gasifier increased.
Experimental Example 4
15 Coal briquettes were manufactured by using anthracite coal. The coal
briquettes were manufactured by mixing 10wt% of anthracite coal calcined at
800℃ and 90wt% of coal A. The rest of experimental processes were the
same as those of the aforementioned Experimental Example 1. Properties and
quality in a hot state of the coal briquettes manufactured according to
20 Experimental Example 3 are listed in the following Table 3.
As the usage amount of calcined anthracite coal was increased, the hot
strength index of the coal briquettes was increased. The reason is that the
anthracite coal is calcined at 800℃ to have a thermally stable characteristic,
18
and as the amount of fixed carbon of the coal briquettes increased and the
amount of volatile matter is relatively reduced, a discharging amount of the
volatile matter is reduced at a high temperature.
Experimental Example 5
Coal briquettes were manufactured by using anthracite coal. The coa5 l
briquettes were manufactured by using 15wt% of anthracite coal calcined at
800℃. The rest of experimental processes were the same as those of the
aforementioned Experimental Example 1. The hot strength index of coal
briquettes as 58.3% was further increased as compared with Experimental
10 Example 3.
Comparative Example 4
Coal briquettes were manufactured by using 90 wt% of coal A and 10
wt% of non-calcined anthracite coal. The rest of experimental processes were
the same as those of the aforementioned Experimental Example 1. The
15 anthracite coal were added to the coal briquettes in a non-calcined state, and as
a result, the hot strength index of the coal briquettes deteriorated. The reason
is that the anthracite coal is not calcined and is not thermally stable.
Comparative Example 5
Coal briquettes were manufactured by using 85wt% of coal A and
20 15wt% of non-calcined anthracite coal. The rest of experimental processes
were the same as those of the aforementioned Experimental Example 1. The
anthracite coal were added to the coal briquettes in a non-calcined state, and as
a result, the hot strength index of the coal briquettes further deteriorated.
(Table 3)
19
Experimental
Example
Raw material mixing ratio
(%)
Technical
analysis of coal
briquettes (%)
Hot
strength
index
(+10
mm, %)
Coal
A
Calcined
anthracite
coal
Noncalcined
anthracite
coal
Coal
ash
Fixed
carbon
Experimental
Example 3
95 5
12.0 56.9 37.7
Experimental
Example 4
90 10
13.6 57.7 56.1
Experimental
Example 5
85 15
13.7 59.1 58.3
Comparative
Example 4
90 10
12.5 57.6 10.8
Comparative
Example 5
85 15
13.4 58.1 9.6
Calcined-brown coal adding experiment
In the aforementioned Experimental Example 3 to Experimental
Example 5, coal briquettes were manufactured by using anthracite coal having
the highest degree of carbonization and brown coal having the lowest degree o5 f
carbonization. Physical properties of brown coal are listed in the following
Table 4. As listed in Table 4, brown coal includes a large amount of water and
20
coal ash and has no coking force. Accordingly, since the coal briquettes
manufactured by brown coal have a characteristic of a low room-temperature
strength such as drop strength or compressive strength, the usage amount of
binder needs to be increased.
(Table 5 4)
Unique water (%) Volatile matter (%) Coal ash (%) Fixed carbon (%)
6.0 33.6 23.2 37.2
Experimental Example 6
Coal briquettes were manufactured by using 95wt% of coal A and 5wt%
of calcined brown coal. Here, the brown coal was calcined and manufactured
10 at 800℃. The rest of manufacturing processes of the coal briquettes were the
same as those in the aforementioned Experimental Example 3. Meanwhile,
quality in a hot state of the coal briquettes with added calcined brown coal was
evaluated. The quality of the coal briquettes adding brown coal is listed in the
following Table 5. In this case, the hot strength index of the coal briquettes
15 was 23.6% and much better than 12.3% which was the hot strength index of the
coal briquettes manufactured according to Comparative Example 1.
Experimental Example 7
Coal briquettes were manufactured by using 90wt% of coal A and
10wt% of calcined brown coal. Here, the brown coal was calcined and
20 manufactured at 800℃. The rest of manufacturing processes of the coal
briquettes were the same as those in the aforementioned Experimental
Example 6. The hot strength index of the manufactured coal briquettes was
21
31.5% and was largely increased according to an increase of an adding amount
of the brown coal as compared with Experimental Example 6.
Experimental Example 8
Coal briquettes were manufactured by using 85wt% of coal A and
15wt% of calcined brown coal. Here, the brown coal was calcined an5 d
manufactured at 800℃. The manufacturing processes of the coal briquettes
were the same as those in the aforementioned Experimental Example 6. The
hot strength index of the manufactured coal briquettes was 43.8% and was
largely increased according to an increase of an adding amount of the brown
10 coal as compared with Experimental Example 7.
Comparative Example 6
Coal briquettes were manufactured by using 90wt% of coal A and
10wt% of non-calcined brown coal. The manufacturing processes of the coal
briquettes were the same as those in the aforementioned Experimental
15 Example 6. The hot strength index of the manufactured coal briquettes was
8.3% and was smaller than the hot strength index of the coal briquettes of
Comparative Example 1 without adding brown coal.
Comparative Example 7
Coal briquettes were manufactured by using 85 wt% of coal A and
20 15wt% of non-calcined brown coal. The manufacturing processes of the coal
briquettes were the same as those in the aforementioned Experimental
Example 6. It could be seen that the hot strength index of the manufactured
coal briquettes was 12.9% as listed in the following Table 5, and the hot
strength index of the coal briquettes was slightly increased according to an
22
increase of the usage amount of brown coal.
(Table 5)
Experimental
Example
Raw material mixing ratio (%)
Hot strength index
(+10 mm, %Coal A )
Calcined
brown coal
Noncalcined
brown coal
Experimental
Example 6
95 5
23.6
Experimental
Example 7
90 10
31.5
Experimental
Example 8
85 15
43.8
Comparative
Example 6
90 10
8.3
Comparative
Example 7
85 15
12.9
It could be seen that when the calcined brown coal is used for
5 manufacturing the coal briquettes, due to thermal stability thereof, the quality in
a hot state of the coal briquettes is largely improved. However, it can be seen
that under the same adding condition, calcined petroleum coke and calcined
anthracite coal have the same effect, and the calcined brown coal has a lower
adding effect than the calcined petroleum coke and the calcined anthracite coal.
10 It was assumed that this was related with the coal ash content of the carbon
23
source. The quality in a hot state of the coal briquettes was largely improved
by adding a small amount of the calcined carbon source to the coal briquettes.
As described above, it can be seen that when the calcined coal is added
during manufacture of the coal briquettes, the quality in a hot state of the coal
briquettes is improved. Therefore, when different kinds of coal other tha5 n
petroleum coke, anthracite coal, and brown coal are calcined and added during
manufacture of the coal briquettes, the quality in a hot state of the coal
briquettes may be improved.
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.

【Claim 1】
A method for manufacturing coal briquettes charged into a dome part of
the melter-gasifier to be rapidly heated in an apparatus for manufacturing
molten iron comprising a melter-gasifier into which reduced irons are charged5 ,
and a reducing furnace connected to the melter-gasifier and providing the
reduced iron, the method comprising:
providing fine coal;
calcinating a carbon source;
10 providing a mixture obtained by mixing the fine coal and the calcined
carbon source; and
providing coal briquettes by molding the mixture,
wherein in the providing of the mixture, the amount of carbon source is
more than 0wt% and 50wt% or less of the mixture.
15
【Claim 2】
The method of claim 1, wherein in the calcinating of the carbon source,
the carbon source is one or more materials selected from a group consisting of
petroleum coke, anthracite coal, and brown coal.
20
【Claim 3】
The method of claim 1, wherein, in the calcinating of the carbon source,
the carbon source is one or more materials selected from a group consisting of
25
sub-bituminous coal, bituminous coal, and semi-anthracite coal.
【Claim 4】
The method of claim 1, wherein in the providing of the mixture, the
amount of carbon source is 5wt% to 30wt%5 .
【Claim 5】
The method of claim 1 further comprising selecting a grain size of the
carbon source, wherein in the providing of the mixture, the grain size of the
10 carbon source is larger than 0 and is 3mm or less.
【Claim 6】
The method of claim 1, wherein in the calcinating of the carbon source,
a calcinating temperature of the carbon source is 700℃ to 1100℃.
15
【Claim 7】
The method of claim 6, wherein the calcinating temperature of the
carbon source is 800℃ to 1000℃.
20 【Claim 8】
The method of claim 1, wherein, in the calcinating of the carbon source,
when the carbon source is petroleum coke, the amount of petroleum coke in the
mixture is 10wt% to 50wt%.
26
【Claim 9】
The method of claim 1, wherein in the calcinating of the carbon source,
when the carbon source is anthracite coal, the amount of anthracite coal in the
mixture is 5wt% to 30wt%.
5
【Claim 10】
The method of claim 1, wherein in the calcinating of the carbon source,
when the carbon source is brown coal, the amount of brown coal in the mixture
is 5wt% to 30wt%.