CROSS-REFERENCE TO RELATED APPLICATION
This application claims priority to and the benefit of Korean Patent
Application No. 10-2013-0164462 and 10-2014-0187759 filed in the Korean
Intellectual Property Office on December 26, 2013 and December 24, 2014, the
entire contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
(a) Field of the Invention
The present invention relates to coal briquettes and a method for
manufacturing the same. More particularly, the present invention relates to
coal briquettes of which cold strength is improved while saving manufacturing
cost, and a method for manufacturing the same.
(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
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
3
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
reduction furnace as a reduction gas.
In general, coal briquettes are manufactured by mixing coal and a binder.
In this case, molasses is used as a binder. The components of the molasses
vary depending on where it is sourced, and it is difficult to consistently control
the ingredients according to a sugar manufacturing process. Therefore, in the
case where a coal briquette is prepared by using molasses as a binder, it is
difficult to control the quality of the coal briquette. Particularly, in the case of
using high moisture molasses, there are problems in that the quality of the coal
briquette is reduced.
The above information disclosed in this Background 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.
SUMMARY OF THE INVENTION
The present invention has been made in an effort to provide a method
for manufacturing coal briquettes having excellent cold strength with low
manufacturing cost. In addition, coal briquettes manufactured using the
above-stated method are provided.
According to an exemplary embodiment of the present invention, a
method for manufacturing coal briquettes being charged into a dome portion of
a melter-gasifier and then quickly heated therein in a molten iron manufacturing
4
apparatus that includes the melter-gasifier into which reduced iron is charged
and a reducing furnace connected with the melter-gasifier and providing the
reduced iron is provided. The method for manufacturing the coal briquettes
according to the exemplary embodiment of the present invention includes: i)
providing pulverized coal; ii) providing a raw sugar binder of 0 to 10 parts by
weight with respect to 100 parts by weight of the pulverized coal; iii) providing a
mixture by adding the raw sugar binder to the pulverized coal; and iv) providing
coal briquettes by shaping the mixture.
In the providing the raw sugar binder, the raw sugar binder may be
provided as a raw sugar solution, and the raw sugar solution may include raw
sugar at about 35 wt% to about 85 wt%.. The raw sugar solution may include
raw sugar at about 65 wt% to about 85 wt%.
The providing the raw sugar binder may include: i) crushing sugarcane
while injecting water; ii) providing sugarcane juice by juicing the crushed
sugarcane; and iii) providing sugarcane syrup by removing impurities from the
sugarcane juice and concentrating the sugarcane juice. In the providing the
sugarcane juice, the amount of solid content included in the sugarcane juice
may be about 10 wt% to about 30 wt%.. Preferably, in the providing the
sugarcane syrup as the raw sugar binder, the amount of solid content included
in the sugarcane juice may be about 50 wt% to 90 wt%. More preferably, the
amount of solid content included in the sugarcane syrup may be about 65 wt%
to about 85 wt%. Further more preferably, the amount of solid content
included in the sugarcane syrup may be about 70 wt% to about 78 wt%.
The providing the raw sugar binder may further include adding paraffin
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to the sugarcane syrup, and the amount of paraffin may be greater than 0 and
less than 1 wt% with respect to the amount of sugarcane syrup. In the
providing the mixture, the mixture may be mixed for about 5 minutes to about 7
minutes at a temperature of about 50°C to about 100°C. In the providing the
sugarcane syrup as the raw sugar binder, the amount of total reducing sugar
included in the sugarcane syrup may be about 65wt% to about 90wt%. In the
providing the pulverized coal, the pulverized coal may be at least one selected
from a group consisting of thermal coal, weak coking coal, brown coal, and
anthracite coal.
The providing the raw sugar binder may include: i) providing a melted
solution by melting the raw sugar with steam of about 70°C to about 120°C; and
ii) providing the raw sugar binder as a raw sugar solution by adding water to the
melted solution and agitating the water-added melted solution at a temperature
about 60°C to about 70°C. .
The method for manufacturing the coal briquettes according to the
exemplary embodiment of the present invention further includes providing at
least one hardener selected from a group consisting of quicklime, slaked lime,
calcium carbonate, cement, bentonite, clay, silica, dolomite, phosphoric acid,
and sulfuric acid. In the providing the mixture, the hardener may be added
more to the pulverized coal and the amount of hardener with respect to 100
parts by weight of the pulverized coal may be 1 part by weight to 6 parts by
weight.
In the providing the raw sugar binder, a ratio of solid content with
respect to the amount of total reducing sugar included in the raw sugar binder
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may be greater than 1 and less than 1.2. In the providing the raw sugar binder,
the raw sugar binder may include at least one selected from a group consisting
of sucrose, glucose, and fructose. The raw sugar binder may include sucrose
and the amount of sucrose with respect to 100 parts by weight of the pulverized
coal may be greater than 0 and less than 4 parts by weight. The amount of
sucrose may be 2 parts by weight to 4 parts by weight. The raw sugar binder
may include glucose and the amount of glucose with respect to 100 parts by
weight of the pulverized coal may be greater than 0 and less than 4 parts by
weight. More preferably, the amount of glucose may be 2 parts by weight to 4
parts by weight
The raw sugar binder may include fructose and the amount of fructose
with respect to 100 parts by the pulverized coal is greater than 0 and less than 4
parts by weight. The amount of fructose may be 2 parts by weight to 4 parts
by weight
The reducing furnace may be a fluidized bed reduction furnace or a
packed bed reduction furnace. In the providing the raw sugar binder, the raw
sugar binder may be provided as a raw sugar solution and the amount of raw
sugar solution with respect to 100 parts by weight of the pulverized coal may be
3 parts by weight to 10 parts by weight. More preferably, the amount of raw
sugar solution may be 6 parts by weight to 10 parts by weight. The amount of
raw sugar solution may be 8 parts by weight to 10 parts by weight. The
amount of sucrose included in the raw sugar solution may be 45 wt% to 75 wt%.
In the providing the raw sugar binder, viscosity of the raw sugar binder may be
100cp to 10,000cp. In the providing the pulverized coal, the amount of
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moisture in the pulverized may be 3 wt% to 12 wt%..
Coal briquette according to another exemplary embodiment of the
present invention is charged into a dome portion of a melter-gasifier and then
quickly heated therein in a molten iron manufacturing apparatus that includes
the melter-gasifier into which reduced iron is charged and a reducing furnace
connected with the melter-gasifier and providing the reduced iron. The coal
briquette includes pulverized coal and a raw sugar binder, and the amount of
raw sugar binder with respect to 100 parts by weight of pulverized coal is
greater than 0 and less than 10 parts by weight, and the raw sugar binder
includes at least one selected from a group consisting of sucrose, glucose, and
fructose.
When the raw sugar binder includes sucrose, the amount of sucrose
may be greater than 0 and less than 4 parts by weight with respect to 100 parts
by weight of the pulverized coal. The amount of sucrose may be 2 parts by
weight to 4 parts by weight. When the raw sugar binder includes fructose, the
amount of fructose may be greater than 0 and less than 4parts by weight with
respect to 100 parts by weight of the pulverized coal. More preferably, the
amount of fructose may be 2 parts by weight to 4parts by weight.
The coal briquette may further include at least one hardener selected
from a group consisting of quicklime, slaked lime, calcium carbonate, cement,
bentonite, clay, silica, dolomite, phosphoric acid, and sulfuric acid, wherein the
amount of hardener is 0.1 part by weight to 6 parts by weight with respect to
100 parts by weight of the pulverized coal. The amount of solid content
included in the raw sugar may be 16 wt% to 96 wt%. More preferably, the
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amount of solid content may be 78 wt% to 96 wt%.
According to the present invention, cold strength of the coal briquettes
can be improved by using a raw sugar binder including sucrose. In addition,
coal briquette that is inexpensive and has excellent cold strength can be
manufactured by using sugarcane juice. When sugarcane juice is used, an
oversaturated concentration recrystallization process may not need to be
repeated for producing raw sugar. In addition, equipment investment cost
consumed for producing concentrated syrup can be reduced, and according to
coal briquettes can be manufactured with low cost. Further, the sugarcane
syrup can be stored for a long period of time.
BRIEF 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 shows a chemical formula of components of a binder used in the
method for manufacturing the coal briquettes of FIG. 1.
FIG. 3 is a schematic graph illustrating variation of compression strength
of coal briquettes according to use of raw sugar and molasses.
FIG. 4 schematically illustrates a raw sugar manufacturing apparatus for
providing the raw sugar binder of FIG. 1.
FIG. 5 schematically illustrates a molten iron manufacturing apparatus
using the coal briquettes of FIG. 1.
FIG. 6 schematically illustrates another molten iron manufacturing
apparatus using the coal briquettes of FIG. 1.
DETAILED DESCRIPTION OF THE EMBODIMENTS
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Terms such as first, second, and third are used to illustrate various
portions, components, regions, layers, and/or sections, but not to limit them.
These terms are used to discriminate the portions, components, regions, layers,
or sections from other portions, components, regions, layers, or sections.
Therefore, a first portion, component, region, layer, or section as described
below may be a second portion, component, region, layer, or section within the
scope of the present invention.
It is to be understood that the terminology used therein 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
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.
Unless it is mentioned otherwise, 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 meanings that coincide with related technical
documents and the contents that are currently disclosed, but are not to be
interpreted as having ideal or very official meanings unless defined otherwise.
It is understood that the term “raw sugar binder” used hereinafter
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includes all materials including sucrose. In addition, it is understood that the
raw sugar binder includes solid and liquid state materials.
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
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
present invention. The flowchart of the method for manufacturing coal
briquettes of FIG. 1 is an exemplary flowchart, and the present invention is not
limited thereto. Thus, the manufacturing method of coal briquettes can be
variously modified.
As shown in FIG. 1, the method for manufacturing coal briquettes
includes: i) providing pulverized coal; ii) providing a raw sugar binder; iii)
providing a mixture by adding the raw sugar binder to the pulverized coal; and
iv) providing coal briquettes by shaping the mixture. The method may further
include other steps.
First, pulverized coal is provided in S10. The pulverized coal is raw
coal. An amount of water mixed in the pulverized coal is maintained with 3
wt% to 12 wt% by mixing the water in advance. When the amount of water
mixed in the pulverized coal is controlled to be in the above-stated range, pores
of pulverized coal particles are blocked. As a result, the hardener and the
binder mixed in the next process cannot penetrate into the pulverized coal
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particles but exist at the outside thereof, and thus the binder couples pulverized
coal particles well, thereby efficiently improving cold strength of coal briquettes.
Further, the coal particles may be crushed to make the size of 90 wt% of more
of the coal particles be less than 3 mm. When sugarcane syrup is used as a
binder, the pulverized coal may be thermal coal, weak coking coal, brown coal,
or anthracite coal, and this will be described later. That is, coal briquettes of
which hot strength is improved by mixing sugarcane syrup and the above-stated
type of pulverized coal can be manufactured. Thus, deterioration of hot
strength and cold strength of the coal briquettes due to a change of coal type of
pulverized coal can be prevented.
Next, a raw sugar binder is provided in S20. As the raw sugar binder,
raw sugar or a raw sugar solution may be used. Sugarcane juice may be used
as the raw sugar solution, or raw sugar may be dissolved in water. The raw
sugar solution may include raw sugar at 35 wt% to 85 wt%. If the amount of
raw sugar is too low, cold strength and hot strength of the coal briquettes may
be deteriorated. On the contrary, when the amount of raw sugar is too high,
moldability of coal briquettes may be deteriorated and manufacturing cost is
increased. Therefore, the amount of raw sugar is adjusted within the abovestated
range. More preferably, the raw sugar solution may include raw sugar
at 65 wt% to 85 wt%. A temperature of the raw sugar solution may be 10 °C to
80 °C. When the temperature of the raw sugar solution is too high, peripheral
equipment may be deteriorated. On the contrary, when the temperature of the
raw sugar solution is too low, flowability of the solution may be deteriorated.
Accordingly, the temperature of the raw sugar solution is adjusted within the
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above-stated range.
The amount of raw sugar binder may be greater than 0 and less than 10
parts by weight with respect to 100 parts by weight of pulverized coal. When
the amount of raw sugar binder is too high, manufacturing cost of the coal
briquettes may be increased. When the amount of raw sugar binder is too low,
cold strength of the coal briquettes may be deteriorated. Thus, the amount of
raw sugar binder is preferably adjusted within the above-stated range.
Viscosity of the raw sugar solution may be adjusted to be within a range
of 100 cp to 10,000 cp. When the viscosity of the raw sugar solution is too low,
the raw sugar solution is not suitable for being used. When the viscosity of the
raw sugar solution is too high, the flowability of the solution is deteriorated,
thereby deteriorating manufacturing process efficiency. Therefore, the
viscosity of the raw sugar solution is preferably adjusted within the above-stated
range.
When coal briquette is manufactured by adding the raw sugar solution to
the pulverized coal as a binder, properties of the coal briquette can be improved.
In addition, since cold strength of the coal briquette can be improved when the
raw sugar solution is used as a binder, the raw sugar solution can replace
molasses that is used as a binder.
The raw sugar solution used in the coal briquettes as a raw sugar binder
should have viscosity of less than 25,000 cp at 25°C for transfer, storage, a
sufficient amount of discharge. For such an above-stated viscosity condition, a
solid content of the raw sugar solution may be greater than zero and less than
85%. In addition, the amount of moisture of the pulverized coal may be 5 wt%
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to 12 wt%. The amount of total reducing sugar in the solid content that is
related with strength of the coal briquette may be 25 wt% or more and 100 wt%
or less. When the amount of solid content of the raw sugar solution is 73 wt%
to 90 wt%, 5 parts by weight to 14 parts by weight of raw sugar solution may be
used as a binder with respect to 100 parts by weight of pulverized coal. In this
case, the amount of moisture of pulverized coal may be 5 wt% to 12 wt%.
Further, a hardener of 2 parts by weight to 6 parts by weight may be used with
respect to 100 parts by weight of pulverized coal. When the amount of solid
content included in the coal briquette is low and the amount of moisture
included in the coal briquette is high, compression strength of the coal briquette
is deteriorated due to moisture.
Preferably, the amount of solid content included in the raw sugar binder
may be 16 wt% to 96 wt%. More preferably, the amount of solid content may
be 35 wt% to 85 wt%. When the amount of solid content is low, cold strength
of the coal briquettes cannot be improved. In addition, when the amount of
solid content is high, the flowability of the binder is deteriorated, thereby
deteriorating manufacturing process efficiency. Accordingly, coal briquettes
having excellent cold strength can be manufactured by using the solid content
within the above-stated range.
Unlike the raw sugar binder, when a molasses binder is condensed, a
solid content becomes higher than 80% such that viscosity becomes 25,000cp,
and accordingly the raw sugar binder cannot be applied to the manufacturing of
coal briquettes. Viscosity of the raw sugar binder is 100cp to 10,000cp, which
is 40 times lower than the viscosity of molasses. Accordingly, the raw sugar
14
binder is appropriate in transfer, storage, or quantitative discharge. In addition,
when the raw sugar binder is mixed with pulverized coal, mixing efficiency is
increased, thereby enhancing strength deviation in coal briquettes.
In S30, the raw sugar binder is added to the pulverized coal such that a
mixture thereof is provided. As a binder, the raw sugar binder is used instead
of molasses. The raw sugar binder includes sucrose, glucose, and fructose.
When sugarcane syrup is used as the raw sugar binder, the mixture may be
mixed for about 5 minutes to about 7 minutes. When mixing time is insufficient,
the sugarcane syrup cannot be evenly dispersed into the pulverized coal. In
addition, when the mixing time is too long, flowability of the mixture is
deteriorated, thereby causing increase of manufacturing cost. Thus, it is
preferred to control the mixing time within the above-stated range. Further, a
mixing temperature of the mixture is preferably about 50°C to about 100°C for
the same reason as described above. Hereinafter, sucrose, glucose, or
fructose will be described in further detail with reference to FIG. 2.
FIG. 2 shows a chemical formula of components of a binder used in the
method for manufacturing coal briquettes of FIG. 1. That is, FIG. 2 shows a
chemical formula of sucrose, glucose, and fructose. A product name of
sucrose is sugar. Sucrose, which is a main component of sugar in sugarcane
juice, sugar beet juice, and acer psedu-sieboldianum, is a disaccharide made
from α-glucose and β-fructose joined in a 1,2 linkage, and has a molecular
formula of C12H22O11. Since sucrose has excellent sweetness and strength,
sucrose is used as a reference material in evaluation of sweeteners. Glucose
is a representative aldohexose, which is a monosaccharide having 6 carbon
15
atoms and an aldehyde group. Glucose is a monosaccharide with a formula
C6H12O6, and is a main compound of carbohydrate metabolism and can
synthesizes 38 ATPs per glucose module. There are D-type and L-type optical
isomers, and only the D-type isomer (D-glucose) occurs in nature and the Dglucose
is called grape sugar. Meanwhile, sucrose is a type of 2-ketohexose,
also referred to as levulose, and is distributed as a glass type and a
disaccharide type or homopolysaccharide type such as levan (β2, fructan) or
inulin (β1, fructan) in fruits, vegetables, and honey.
Table 1 shows characteristics of a coal briquette binder manufactured
using sucrose, glucose, fructose, and molasses as a coal briquette binder. As
shown in Table 1, when the coal briquette is manufactured, properties of coal
briquette is excellent in the order or sucrose, fructose, and glucose. Here,
sucrose can replace molasses because it has excellent compression strength
and drop strength compared to molasses.
(Table 1)
Section Sucrose Glucose Fructose Molasses
Compression
strength (after
1hr)
56.6 28.0 40.0 50.8
Drop strength 99.8% 85.0% 42.9% 95.3%
Technical
analysis
VM 30.02 29.74 30.52 29.52
Ash 12.84 12.95 13.34 13.48
FC 56.61 56.88 55.69 56.56
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In manufacturing of coal briquettes, hot strength and cold strength of the
coal briquettes are improved through caramelization reaction between a
monosaccharide and a hardener. Thus, properties of the coal briquette can be
improved by adding sucrose, glues, or fructose to pulverized coal as a binder or
adding a raw sugar solution to pulverized coal. Meanwhile, the
monosaccharide should be deformed to a polymer in order to prevent the
monosaccharide from being easily attached to a shaping roll, and cold strength
is not deteriorated.
When sucrose is mixed to pulverized, the amount of sucrose with
respect to 100 parts by weight of pulverized coal may be 0 to 5 parts by weight.
More preferably, the amount of sucrose may be about 2 parts by weight to
about 5 parts by weight. When the amount of sucrose is too low, cold strength
of the coal briquette may be deteriorated. When the amount of sucrose is too
high, the mixture cannot be easily shaped into coal briquette and the mixture is
attached to a roll. Therefore, the amount of sucrose is adjusted within the
above-stated range.
Glucose may be mixed to pulverized coal as a binder. When the
glucose is mixed, the amount of glucose with respect to 100 parts by weight of
pulverized coal may be about 4 parts by weight or less. More preferably, the
amount of glucose may be about 2 parts by weight to 4 parts by weight. When
the amount of glucose is too low, cold strength of the coal briquette may be
deteriorated. When the amount of glucose is too high, the mixture cannot be
easily shaped into coal briquette and the mixture is attached to a roll.
Therefore, the amount of glucose is adjusted within the above-stated range.
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Fructose may be mixed to pulverized coal as a binder. When the
fructose is mixed, the amount of fructose with respect to 100 parts by weight of
pulverized coal may be about 4 parts by weight or less. More preferably, the
amount of fructose may be 2 parts by weight to 4 parts by weight. When the
amount of fructose is too low, cold strength of the coal briquette may be
deteriorated. When the amount of fructose is too high, the mixture cannot be
easily shaped into coal briquette and the fructose is attached to a roll.
Therefore, the amount of fructose is adjusted within the above-stated range.
As a binder, a raw sugar solution including inexpensive sucrose may be
used to manufacture coal briquettes. In this case, the raw sugar solution
includes a solid content of 45 wt% or more. More preferably, the raw sugar
solution includes a solid content of about 45 wt% to about 85 wt%. Sucrose,
glucose, fructose may be included in the solid content. When the amount of
solid content included in the raw sugar solution is too low, cold strength of the
coal briquettes may be deteriorated. In addition, when the amount of solid
content included in the raw sugar solution is too high, moisture lacks in
manufacturing of a mixture, thereby causing the mixture to be non-uniformly
mixed. Thus, the amount of solid content included in the raw sugar solution is
adjusted within the above-stated range.
The amount of raw sugar solution mixed with respect to 100 parts by
weight of pulverized coal may be about 3 parts by weight to about 10 parts by
weight. Preferably, the amount of raw sugar solution may be 6 parts by weight
to 10 parts by weight. More preferably, the amount of raw sugar solution may
be 7 parts by weight to 10 parts by weight. When the amount of raw sugar
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solution is too low, cold strength of coal briquettes may be deteriorated. When
the amount of raw sugar solution is too high, the mixture is not easily shaped to
coal briquettes and easily attached to a roll. Therefore, the amount of raw
sugar solution is adjusted within the above-stated range.
As a hardener, quicklime, slaked lime, calcium carbonate, cement,
bentonite, clay, silica, dolomite, phosphoric acid, and sulfuric acid may be used.
Preferably, quicklime is used as a hardener, together with the raw sugar binder
to manufacture coal briquette having excellent cold strength and hot strength.
When sugarcane syrup is used as a binder, quicklime and slaked lime can
remove carbon dioxide in the sugarcane syrup thereby assuring volume stability
of the sugarcane syrup.
Referring back to FIG. 1, coal briquettes are provided by shaping the
mixture in S40. For example, although it is not illustrated in FIG. 1, the mixture
is charged between a pair of rolls, each rotating in the opposite direction so as
to manufacture pocket-type or strip-type coal briquette. In this case, the coal
briquette can be manufactured at a temperature of about 3°C to about 300°C.
Since the coal briquette is manufactured at the above-stated temperature range,
hot strength and cold strength of the coal briquettes can be improved. In
addition, since a raw sugar binder is included in the coal briquette, cold strength
of the coal briquette can be improved.
Meanwhile, components of a binder included in the coal briquette can be
analyzed as follows. First, coal briquette of 100g is finely crushed. Then,
ethanol of 500mL is added, and liquid and coal are separated. Next, solids are
separated by filtering liquid, the liquid is removed by using a rotary evaporator,
19
and the remainder is dissolved in water to measure 0.01% of sucrose is
measured. Since a general ratio of sucrose in molasses is about 30 wt% to
about 40 wt%, when the amount of sucrose exceeds the general ratio, raw
sugar and sugarcane syrup may be expected to be used as coal briquette
binders.
FIG. 3 is a graph schematically illustrating variation of compression
strength of coal briquettes according to use of a raw sugar binder and use of a
molasses binder. That is, compression strengths of coal briquettes when the
amount of raw sugar binders and molasses binders included in the coal
briquettes are respectively 2 wt%, 4 wt%, 6 wt%, 8 wt%, and 10 wt% are shown
in the graph. Here, as the raw sugar binder, a raw sugar solution of about 60%
to about 80% is used.
As shown in FIG. 3, coal briquette manufactured using the raw sugar
solution as a binder has higher compression strength compared to coal
briquette manufactured using a molasses binder. Thus, when the raw sugar is
used as a binder of coal briquette, cold strength of the coal briquette is
improved compared to coal briquette where molasses is used as a binder. In
addition, when the raw sugar is used as a binder, cold strength of coal briquette
is improved, and accordingly, the amount of use of binder can be more reduced.
Meanwhile, raw sugar can be used not only for manufacturing coal
briquette but also for manufacturing a pellet. In addition, apart from the raw
sugar, raw sugar may be used in manufacturing of cement or feedstuff using a
pellet. In addition to the above-stated raw sugar components, lactose, maltose,
and raffinose may also be used. Such a disaccharide or trisaccharide
20
indicates cold strength using salt formation according to independent use or
mixing with a hardener.
A hardener used in manufactured of coal briquette may include
quicklime, slaked lime, calcium carbonate, cement, bentonite, clay, silica,
dolomite, phosphoric acid, sulfuric acid, and the like. The hardener is
combined with raw sugar such that hot strength and cold strength of the coal
briquettes can be significantly improved. The amount of hardener may be
about 0.1 parts by weight to 6 parts by weight with respect to 10 parts by weight
of pulverized coal. Combination of the hardener of the above-stated range and
the above-stated raw sugar can significantly improve cold strength of the coal
briquettes.
The amount of sucrose included in the coal briquette may be 0 to 4 parts
by weight with respect to 100 parts by weight of pulverized coal. More
preferably, the amount of sucrose may be 2 parts by weight to 4 parts by weight.
When the amount of sucrose is adjusted within the above-stated range, a
mixture is not easily attached to a roll during shaping and cold strength and hot
strength of the coal briquettes can be improved.
FIG. 4 schematically illustrates a raw sugar manufacturing apparatus 15
for providing a raw sugar binder. The raw sugar manufacturing apparatus 15
of FIG. 4 is an exemplary raw sugar manufacturing apparatus, and the present
invention is not limited thereto. Therefore, the raw sugar manufacturing
apparatus 15 can be variously modified.
As shown in FIG. 4, the raw sugar manufacturing apparatus 15 includes
a crusher 151, a juice extractor 152, a sugarcane juice storage bin 153, a
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vacuum fan 154, an impurity remover 155, a centrifugal separator 156, a
sugarcane extractor 157, and a quicklime storage bin 159. The raw sugar
manufacturing apparatus 15 may further include other constituent elements as
necessary.
The crusher 151 has protrusions and depressions formed at the surface
thereof such that sugarcane finely charged thereinto together with water can be
crushed. Sugarcane juice is extracted from the finely crushed sugarcane in
the juice extractor 152. The sugarcane juice is stored in the sugarcane juice
storage bin 153. The sugarcane juice is manufactured by crushing the
sugarcane, but many impurities are mixed in the sugarcane during cultivation
thereof. Thus, quicklime is injected into the sugarcane juice transferred to the
impurity remover 155 from the quicklime storage bin 159 so as to manufacture
sugarcane syrup after removing the impurities in the sugarcane juice. The
sugarcane syrup may be used as a coal briquette binder by being directly used
or by being concentrated. The sugarcane syrup has an advantage over
molasses in pipeline transport because the sugarcane syrup has very low
viscosity. In addition, since the sugarcane syrup has excellent mixing
efficiency, a cold strength deviation of coal briquettes can be reduced by
uniform mixing. Further, the sugarcane syrup stably maintains the cold
strength of coal briquettes without regard to a change in coal type.
A solid content in the sugarcane syrup may be 50 wt% to 90 wt%.
Preferably, the solid content may be 50 wt% to 80 wt%. More preferably, the
solid content included in the sugarcane syrup may be 65 wt% to 85 wt%.
Further more preferably, the solid content included in the sugarcane syrup may
22
be 70 wt% to 78 wt%.
When the solid content is too low, sufficient strength of coal briquettes
cannot be assured and breeding of microorganisms cannot be suppressed.
Particularly, microorganisms plentifully included in the sugarcane syrup reduce
sugar components by fermenting sucrose included in the sugarcane syrup into
alcohol components so that cold strength of the coal briquettes is deteriorated.
Thus, fermentation of the sugarcane syrup due to the microorganisms needs to
be prevented. In addition, when the solid content is too high, transfer, storage,
and discharge of the sugarcane syrup may be difficult. Therefore, the amount
of solid contents is preferably adjusted by adjusting the amount of water and the
amount of sugarcane. For long-term storage of the sugarcane syrup for
transfer, 1 wt% or less of paraffin may be added to the sugarcane syrup.
Paraffin may prevent generation of foam in the sugarcane syrup due to organic
acids. That is, foam is generated when carbon dioxide in the sugarcane syrup
is discharged to the outside. When the sugarcane syrup is stirred, a container
storing the sugarcane syrup may explode due to an increase of volume or
generation of foam because of existence of an organic material, which is a
surfactant that generates foam. Accordingly, paraffin is used to prevent the
generation of foam.
Table 2 shows a solid content and viscosity of the solid content
according to a total amount of reducing sugar of the sugarcane syrup.
(Table 2)
NO. Solid content
(wt%)
Total reducing
sugar (wt%)
Viscosity (cp,
25℃)
23
1 16 15 100
2 48 46 110
3 58 54 150
4 68 65 300
5 78 73 500
6 88 83 2,000
7 96 90 500,000
As shown in Table 2, when the solid content is 78 wt%, viscosity of
sugarcane syrup is 500 cp, which satisfies the viscosity condition of less than
25,000 cp so as to be used as a coal briquette binder. Thus, the sugarcane
syrup can be industrially used. In further detail, the amount of total reducing
sugar in the sugarcane syrup is preferably 65 wt% to 90 wt%. When the
amount of the total reducing sugar is too low, the sugarcane syrup may be
fermented. Thus, for stable storage and use of the sugarcane syrup within a
year, quicklime or slaked lime is added to the sugarcane syrup to separate
precipitates. In addition, when the amount of total reducing sugar is too high,
viscosity of the sugarcane syrup is increased so that it cannot be applied to a
substantial process. Accordingly, the amount of total reducing sugar is
adjusted within the above-stated range.
The slaked lime used to remove the impurity shown in FIG. 4 may be
collected to be reused. Impurity-removed sugarcane juice is concentrated by
being heated in the sugarcane extractor 157 and then used as a raw sugar
binder. That is, the sugarcane syrup manufactured from the raw sugar
24
manufacturing apparatus 15 of FIG. 4 is directly used as a raw sugar binder so
as to manufacture coal briquettes. The sugarcane syrup is extracted to be
distilled and recrystallized with a vacuum fan 154 such that massecuite is
extracted therefrom. Massecuite includes raw sugar crystals and solid
contents of 90 wt% or more. In addition, raw sugar is extracted through a
centrifugal process in the centrifugal separator 156. Such a process is
continuously repeated in the vacuum fan 154 and the centrifugal separator 156
to extract raw sugar and discharge molasses, which is a by-product.
The amount of moisture in the raw sugar binder acquired through the
above-stated process can be easily adjusted. Thus, a type of coal having a
large amount of moisture may also be used. When the amount of moisture in
the sugarcane syrup is too high, strength of coal briquettes may be deteriorated
due to the excessive amount of moisture. On the contrary, when the amount
of moisture in the sugarcane syrup is too low, for example, when the amount of
moisture in the sugarcane syrup is 10 wt% or less, a transfer problem may
occur and the strength of coal briquettes may be deteriorated due to the lack of
moisture. In addition, various types of coal may be used when the raw sugar
binder is used instead of using molasses. Table 3 shows a result of
component analysis of sugarcane juice, sugarcane syrup, and raw sugar
acquired by the raw sugar manufacturing apparatus 15 of FIG. 4.
(Table 3)
NO
.
Substance Disaccharide
s
/monosacch
Disaccharide
s (%)
sucrose
Monosaccha
rides (%)
glucose +
Impurities
(%)
25
arides fructose
1 Sugarcane
juice
2-20 10-20 1-5 -
2 Sugarcane
syrup
4-60 40-60 1-10 -
3 Raw sugar 90 90-99 0-1 0-1
As shown in Table 3, all of the sugarcane juice, sugarcane syrup, and
raw sugar acquired from the raw sugar manufacturing apparatus 15 of FIG. 4
include sucrose, glucose, or fructose. Here, sucrose is a disaccharide, and
glucose and fructose are monosaccharides.
Thus, the raw sugar binder can provide coal briquettes with the same
degree of strength even through being used in a lesser amount compared to a
molasses binder. As a result, cost for manufacturing coal briquettes can be
reduced. That is, in order to acquire the above-stated degree of strength of the
coal briquettes, a ratio of disaccharide compared to monosaccharide is
preferably 4 to 1000. More preferably, the ratio of disaccharide compared to
monosaccharide is 10 to 1000.
Meanwhile, since the sugarcane syrup can be produced by juicing and
concentrating sugarcane, a producing process is simple and a crystal
production process that requires expensive investment can be omitted. In
addition, a process for making a substance in a solution state can also be
omitted. That is, the entire process can be simplified, thereby improving
process efficiency. In addition, when a sugarcane producing area and a coal
26
briquette manufacturing area are close to each other, transport cost can be
saved, and since cost of sugarcane is cheaper than raw sugar, a price of the
binder can be reduced, thereby saving manufacturing cost. Further, since the
sugarcane syrup is not well-attached to a surface of the pair of rollers, shaping
failure can be prevented, and as viscosity of the sugarcane syrup is lower than
that of molasses, the sugarcane syrup can be uniformly coated to coal
briquettes. Meanwhile, since the sugarcane syrup has excellent adhesive
strength compared to molasses, cold strength of the coal briquettes can be
improved, and therefore deterioration of cold strength and hot strength due to
variation of types of coal briquettes can be prevented.
FIG. 5 schematically illustrates a molten iron manufacturing apparatus
100 using the coal briquettes manufactured in FIG. 1. A structure of the
molten iron manufacturing apparatus 100 of FIG. 5 is an exemplarily structure,
and the present invention is not limited thereto. Therefore, the structure of the
molten iron manufacturing apparatus 100 of FIG. 5 can be variously modified.
As shown in FIG. 5, the molten iron manufacturing apparatus
100includes a melter-gasifier 10, fluidized bed reducing furnaces 22, a reduced
iron compressor 40, and a compressed reduced iron storage bin 50. Here, the
compressed reduced iron storage bin 50 may be omitted.
The manufactured coal briquettes are charged into the melter-gasifier 10
and form a coal-packed bed in the melter-gasifier 10. Here, the coal briquettes
cause generation of a reduction gas in the melter-gasifier 10, and the reduction
gas is supplied to the fluidized-bed reduction furnaces 22. Fine iron ores are
supplied to the plurality of fluidized-bed reduction furnaces 22 having fluidized
27
beds, and are fluidized by the reduction gas supplied to the fluidized-bed
reduction furnaces 22 from the melter-gasifier 10 such that reduced iron is
manufactured. The reduced iron is compressed by the reduced iron
compressor 40 and then stored in the compressed reduced iron storage bin 50.
The compressed reduced iron is supplied to the melter-gasifier 10 from the
compression reduced iron storage bin 50 and then melted in the melter-gasifier
10.
A dome portion 101 is provided in an upper portion of the melter-gasifier
10. That is, a space that is wider than other portions of the melter-gasifier 10
is formed, and high-temperature reduction gas exists in the space. Thus, the
coal briquettes charged into the dome portion 101 can be easily divided by the
high-temperature reduction gas. That is, since the coal briquettes are charged
into the upper portion of the melter-gasifier 10 maintained at 1000 C, the coal
briquettes are subjected to rapid thermal impact. Accordingly, the coal
briquettes may be differentiated while moving to the lower portion of the meltergasifier
10.
However, coal briquettes manufactured by the method of FIG. 1 have
high hot strength, and therefore the coal briquettes are not differentiated at the
dome portion of the melter-gasifier 10 and fall to the bottom of the meltergasifier
10 while being maintained as char. The char generated from thermal
decomposition of coal briquettes moves to the bottom of the melter-gasifier 10
and then exothermically reacts with oxygen supplied through a tuyere 30.
Thus, the coal briquettes can be used as a heat source that maintains the
melter-gasifier 10 at a high temperature. Meanwhile, since char provides
28
ventilation, a large amount of gas generated from the lower portion of the
melter-gasifier 10 and reduced iron supplied from the fluidized-bed reduction
furnace 22 can more easily and uniformly pass through the coal-packed bed in
the melter-gasifier 10.
In addition to the above-stated coal briquettes, lump carbon ash or coke
may be charged into the melter-gasifier 10, as necessary. The tuyere 30 is
provided in an outer wall of the melter-gasifier 10 for injection of oxygen.
Oxygen is injected into the coal-packed bed such that a fire zone is formed.
The coal briquettes may be burned in the fire zone to generate the reduction
gas.
Cold strength of the coal briquette can be maximized by using a raw
sugar binder including sucrose, and manufacturing cost of the coal briquette
can be reduced. In addition, the efficiency of the operation of the fluidized bed
reduction furnace can be maximized, and the distribution cost for long-distance
transportation of molasses can be reduced.
FIG. 6 schematically illustrates another molten iron manufacturing
apparatus 200 using the coal briquettes manufactured in FIG. 1. A structure of
the molten iron manufacturing apparatus 200 of FIG. 6 is an exemplarily
structure, and the present invention is not limited thereto. Therefore, the
structure of the molten iron manufacturing apparatus 200 of FIG. 6 can be
variously modified. The structure of the molten iron manufacturing apparatus
200 of FIG. 6 is similar to the structure of the molten iron manufacturing
apparatus 100 of FIG. 5, and therefore like reference numerals designate like
elements in the molten iron production apparatus 100 of FIG.5, and a detailed
29
description thereof will be omitted.
The molten iron manufacturing apparatus 200 of FIG. 6 includes a
melter-gasifier 10 and packed-bed reduction furnaces 20. The molten iron
manufacturing device 200 may include other devices as necessary. Iron ore is
charged into the plurality of packed-bed reduction furnaces 22 and then
reduced. The iron ore charged into each packed-bed reduction furnace 22 is
dried in advance and then passed through the packed-bed reduction furnace 22
such that reduced iron is manufactured. The packed-bed reduction furnace 22
receives the reduction gas from the melter-gasifier 10 and thus forms a packed
bed therein.
Hereinafter, the present invention will be described in further detail with
reference to experimental examples. The experimental examples are used
only to illustrate the present invention, and are not meant to be restrictive.
Experimental Example
Experiment of manufacturing coal briquette using raw sugar solution as
binder
Coal briquette including coal, a binder, a hardener, and moisture was
manufactured. First, coal and the hardener were mixed for about 1 minute to
about 20 minutes and the binder was mixed to the mixture of the coal and the
hardener for about 1 minute to about 20 minutes. As the binder, raw sugar
including sucrose, glucose, and fructose was used. Each binder was
manufactured as a raw sugar solution of about 50 wt% to about 90wt% of raw
sugar solution. The raw sugar solution was manufactured by being agitated at
a temperature of about 60°C to about 90°C, and no component change
30
occurred. As a binder, a solution in which raw sugar was completely dissolved
or a solution in which raw sugar was not completely dissolved was usable.
The binder was added at a temperature of about 10°C to about 80°C with
viscosity of about 1cp to 60,000cp. The amount of sucrose, glucose, and
fructose included in the raw sugar were calculated with respect to a weight
ration of coal and then added.
Table 4 shows components of a raw sugar solution according to the
amount of raw sugar added to the raw sugar solution and components of
molasses. In further detail, in Table 4, components of raw sugar solutions of
75 wt%, 65 wt%, 55 wt%, 45 wt% and components of molasses are compared.
In Table 4, viscosity of the binder is increased as a concentration of raw sugar
included in the binder is high or a manufacturing temperature is low.
(Table 4)
Section Raw
sugar 75
wt%
solution
Raw
sugar 65
wt%
solution
Raw
sugar 55
wt%
solution
Raw
sugar 45
wt%
solution
Molasses
Brix (%) 74.7 64.8 54.9 44.9 81.8
Ratio of sucrose 100 100 100 100 35.0
Total reduced
sugar
75.5 65.6 55.7 45.6 51.0
Manufacturing
temperature
(℃)
70 43 m∙Pa 30.1
m∙Pa
10.2
m∙Pa
5.4 m∙Pa -
60 48 m∙Pa 28.7 9.8 m∙Pa 5.2 m∙Pa -
31
m∙Pa
50 61 m∙Pa 27.5
m∙Pa
8.7 m∙Pa 5.2 m∙Pa -
40 148
m∙Pa
26.4
m∙Pa
7.6 m∙Pa 5.6 m∙Pa -
30 171
m∙Pa
26.2
m∙Pa
6.8 m∙Pa 5.4 m∙Pa -
Experimental Example 1
Coal briquettes were manufactured by using 2.7 parts by weight of CaO
as a hardener and 10 parts by weight of 75% raw sugar solution were mixed
with respect to 100 parts by weight of coal. The remaining experiment
processes were the same as the above-stated experimental example.
Experimental Example 2
Coal briquettes were manufactured by using 2.7 parts by weight of CaO
as a hardener and 8 parts by weight of 75% raw sugar solution were mixed with
respect to 100 parts by weight of coal. The remaining experiment processes
were the same as Experimental Example 7.
Experimental Example 3
Coal briquettes were manufactured by using 2.7 parts by weight of CaO
as a hardener and 6 parts by weight of 75% raw sugar solution were mixed with
respect to 100 parts by weight of coal. The remaining experiment processes
were the same as Experimental Example 7.
Experimental Example 4
32
Coal briquettes were manufactured by using 2.7 parts by weight of CaO
as a hardener and 10 parts by weight of 65% raw sugar solution were mixed
with respect to 100 parts by weight of coal. The remaining experiment
processes were the same as Experimental Example 7.
Experimental Example 5
Coal briquettes were manufactured by using 2.7 parts by weight of CaO
as a hardener and 8 parts by weight of 65% raw sugar solution were mixed with
respect to 100 parts by weight of coal. The remaining experiment processes
were the same as Experimental Example 7.
Experimental Example 6
Coal briquettes were manufactured by using 2.7 parts by weight of CaO
as a hardener and 10 parts by weight of 55% raw sugar solution were mixed
with respect to 100 parts by weight of coal. The remaining experiment
processes were the same as Experimental Example 7.
Experimental Example 7
Coal briquettes were manufactured by using 2.7 parts by weight of CaO
as a hardener and 10 parts by weight of 45% raw sugar solution were mixed
with respect to 100 parts by weight of coal. The remaining experiment
processes were the same as Experimental Example 7.
Comparative Example 1
Coal briquettes were manufactured by using 2.7 parts by weight of CaO
as a hardener and 10 parts by weight of molasses were mixed with respect to
100 parts by weight of coal. The remaining experiment processes were the
same as Experimental Example 7.
33
Experiment result of coal briquette manufacturing using raw sugar
solution as binder
Cold strength and hot strength of coal briquettes manufactured
according to Experimental Example 1 to Experimental Example 7 and
Comparative Example 1 were measured, and a technical analysis was
performed. Such an experiment process can be easily understood by those
skilled in the art, and therefore the detailed description is omitted.
Table 5 shows an experiment result of coal briquettes manufactured
according to Experimental Example 1 to Experimental Example 7 and
Comparative Example 1. As shown in Table 5, when the raw sugar binder was
used as a binder instead of molasses, cold strength and hot strength of the coal
briquettes were improved.
(Table 5)
Section Comp
arativ
e Ex.
1
Exper
iment
al Ex.
1
Exper
iment
al Ex.
2
Exper
iment
al Ex.
3
Exper
iment
al Ex.
4
Exper
iment
al Ex.
5
Exper
iment
al Ex.
6
Exper
iment
al Ex.
7
Mi
xin
g
rati
o
CaO
(wt%)
2.7 2.7 2.7 2.7 2.7 2.7 2.7 2.7
Molass
es
(solid
content)
10 0 0 0 0 0 0 0
Raw 0 10 8 6 0 0 0 0
34
sugar
75%
solution
(solid
content)
(7.5) (8) (6)
Raw
sugar
65%
solution
(solid
content)
0 0 0 0 10
(6.5)
8
(5.2)
0 0
Raw
sugar
55%
solution
(solid
content)
0 0 0 0 0 0 10
(5.5)
0
Raw
sugar
45%
solution
(solid
content)
0 0 0 0 0 0 0 10
(5.5)
Qu Compre 50.5 83.8 64.8 52.4 70.2 56.2 50.1 51.6
35
alit
y
ev
alu
ati
on
ssion
strength
(kg∙f)
Drop
strength
(4
times)
97.5 98.1 97.1 97.2 97.1 97.1 96.1 96.3
Drop
strength
(8
times)
94.1 96.6 93.3 93.4 95.6 93.3 93.1 93.7
HTS 16 12.0 12.1 14.7 14.6 12.4 14.7 11.1 11.5
HTS 13 64.4 63.6 61.3 61.2 63.3 61.3 62.1 63.5
HTS 10 92.6 92.1 91.5 92.4 91.1 91.5 90.8 91.8
I-Drum 80.5 78.6 78.3 79.5 78.6 78.3 79.5 80.5
Coal briquette manufacturing experiment using sugarcane syrup as
binder
Coal briquettes including pulverized coal, sugarcane syrup concentrate,
a hardener, and moisture were manufactured. The pulverized coal was
crushed such that particle sizes of 90 wt% or more were 3mm or less, and the
amount of moisture was controlled to be 12 wt% or less. The pulverized coal
and the hardener were mixed for about 20 minutes and the sugarcane syrup
concentrate was added to the mixture and then mixed for about 20 minutes.
36
The sugarcane syrup concentrate included a solid content of about 65 wt% to
about 90 wt%. Sugarcane syrup of solid content of 50 wt% generated from
raw sugar manufacturing process was concentrated by being distilled at 10
mbar to 30 mbar under vacuum at a temperature of 80°C to 200°C such that the
sugarcane syrup concentrate was made. When the sugarcane syrup was
concentrated, a liquid-state paraffin of 0.1 wt% to 0.5 wt% was added to remove
foams generated during an early concentration stage.
Experimental Example 8
2.7 parts by weight of CaO and 10 parts by weight of solution of
sugarcane syrup 78 % were mixed with respect to 100 parts by weight of
pulverized coal to manufacture coal briquettes. The remaining experiment
processes can be can be easily understood by those skilled in the art, and
therefore the detailed description is omitted.
Experimental Example 9
2.7 parts by weight of CaO and 9 parts by weight of solution of
sugarcane syrup 78 % were mixed with respect to 100 parts by weight of
pulverized coal to manufacture coal briquettes. The remaining experiment
processes were the same as Experimental Example 8.
Experimental Example 10
2.7 parts by weight of CaO and 8 parts by weight of solution of
sugarcane syrup 78 % were mixed with respect to 100 parts by weight of
pulverized coal to manufacture coal briquettes. The remaining experiment
processes were the same as Experimental Example 8.
Experimental Example 11
37
2.7 parts by weight of CaO and 6 parts by weight of solution of
sugarcane syrup 78 % were mixed with respect to 100 parts by weight of
pulverized coal to manufacture coal briquettes. The remaining experiment
processes were the same as Experimental Example 8.
Experimental Example 12
2.7 parts by weight of CaO and 10 parts by weight of solution of
sugarcane syrup 68 % were mixed with respect to 100 parts by weight of
pulverized coal to manufacture coal briquettes. The remaining experiment
processes were the same as Experimental Example 8.
Experimental Example 13
2.7 parts by weight of CaO and 9 parts by weight of solution of
sugarcane syrup 68 % were mixed with respect to 100 parts by weight of
pulverized coal to manufacture coal briquettes. The remaining experiment
processes were the same as Experimental Example 8.
Experimental Example 14
2.7 parts by weight of CaO and 8 parts by weight of solution of
sugarcane syrup 68 % were mixed with respect to 100 parts by weight of
pulverized coal to manufacture coal briquettes. The remaining experiment
processes were the same as Experimental Example 8.
Experimental Example 15
2.7 parts by weight of CaO and 7 parts by weight of solution of
sugarcane syrup 68 % were mixed with respect to 100 parts by weight of
pulverized coal to manufacture coal briquettes. The remaining experiment
processes were the same as Experimental Example 8.
38
Experiment result of coal briquette manufacturing using sugarcane syrup
as binder
Compression strength of coal briquettes manufactured according to the
above-stated Experimental Example 8 to Experimental Example 15 were
measured. Since such an experiment process can be easily understood by
those skilled in the art, the detailed description is omitted.
Table 6 shows an experiment result of coal briquettes manufactured
according to the above-stated Experimental Example 8 to Experimental
Example 15. In Table 6, compression strengths of coal briquettes are shown.
(Table 6) (*Ex. is short for Experimental Example)
Section Ex.
8
Ex.
9
Ex.
10
Ex.
11
Ex.
12
Ex.
13
Ex.
14
Ex.
15
Mixing
ratio
Moisture in
coal (wt%)
8.5 8.5 8.5 8.5 8.5 8.5 8.5 8.5
CaO (wt%) 2.7 2.7 2.7 2.7 2.7 2.7 2.7 2.7
Sugarcane
syrup 78%
10 9 8 6 0 0 0 0
Sugarcane
syrup 68%
0 0 0 0 10 9 8 7
Quality
evaluation
Compression
strength (kg∙f)
80 72 66 50 70 63 56 50
Drop strength 99 95 95 93 95 95 93 90
Shaping failure rate - - - - 2% 2% 2% 2%
39
As shown in Table 6, coal briquettes manufactured in Experimental
example 8 to Experimental Example 15 had excellent compression strength and
drop strength. In particular, compression strength and drop strength were
more excellent when a solution of sugarcane syrup 78% was used instead of
using a solution of sugarcane syrup 68%. As shown in Experimental Example
11 and Experimental Example 15, although a smaller amount of sugarcane
syrup compared to the molasses binder of Comparative Example 1 was used,
coal briquette having almost the same compression strength could be
manufactured. That is, when the sugarcane syrup 78% solution was used in
Experimental Example 11, a usage amount of binder could be reduced by about
40% compared to molasses of Comparative Example 1. In addition, when the
sugarcane syrup 68% solution was used in Experimental Example 15, a usage
amount of binder could be reduced by about 30% compared to Comparative
Example 1.
As described above, when the raw sugar binder was used, an alkali
component was not piled in the fluid-bed reducing furnace such that nozzles
could be prevented from being blocked. In addition, cold strength and hot
strength of the coal briquettes were increased. Meanwhile, coal briquette
having excellent strength could be manufactured by using a small amount of
sugarcane syrup as a binder.
Experiment of manufacturing coal briquette according to solid condent
variation of sugarcane syrup
Experimental Example 16
Coal briquettes were manufactured using sugarcane syrup which has
40
been concentrated and thus the amount of solid content was 16 wt%. The
remaining experiment processes were the same as Experimental Example 8.
Experimental Example 17
Coal briquettes were manufactured using sugarcane syrup which has
been concentrated and thus the amount of solid content was 48 wt%. The
remaining experiment processes were the same as Experimental Example 8.
Experimental Example 18
Coal briquettes were manufactured using sugarcane syrup which has
been concentrated and thus the amount of solid content was 58 wt%. The
remaining experiment processes were the same as Experimental Example 8.
Experimental Example 19
Coal briquettes were manufactured using sugarcane syrup which has
been concentrated and thus the amount of solid content was 68 wt%. The
remaining experiment processes were the same as Experimental Example 8.
Experimental Example 20
Coal briquettes were manufactured using sugarcane syrup which has
been concentrated and thus the amount of solid content was 78 wt%. The
remaining experiment processes were the same as Experimental Example 8.
Experimental Example 21
Coal briquettes were manufactured using sugarcane syrup which has
been concentrated and thus the amount of solid content was 88 wt%. The
remaining experiment processes were the same as Experimental Example 8.
Experimental Example 22
Coal briquettes were manufactured using sugarcane syrup which has
41
been concentrated and thus the amount of solid content was 96 wt%. The
remaining experiment processes were the same as Experimental Example 8.
Experiment result of coal briquette manufacturing according to solid
content variation of sugarcane syrup
Compression strength and drop strength of coal briquettes
manufactured according to the above-stated Experimental Example 16 to
Experimental Example 22 were measured. That is, the coal briquette was left
for about 1 hour at a room temperature and then compression strength and
drop strength of the coal briquette were measured, and the coal briquette was
dried for about 15 minutes at 80°C, and the compression strength and drop
strength were measured again. The results are shown in Table 7.
(Table 7)
Experiment
al Example
Viscosit
y (cp)
TS As
h
1 Hr. at room
temperature
Dried for 15 min. at
80℃
Compressi
on strength
Drop
strengt
h
Compressi
on strength
Drop
strengt
h
Experiment
al Ex. 16
100 15 1 26 85 75 85
Experiment
al Ex. 17
110 46 2 55 90 100 95
Experiment
al Ex. 18
150 54.
4
3 60 95 100 95
Experiment 300 64. 4 70 95 100 95
42
al Ex. 19 5
Experiment
al Ex. 20
500 73 5 80 95 120 99
Experiment
al Ex. 21
2,000 82.
5
5.5 90 99 130 99
Experiment
al Ex. 22
5,000 90 6 100 99 140 99
As shown in Table 7, as the amount of solid content included in the
sugarcane syrup used as a binder in Experimental Example 16 to Experimental
Example 22 is increased, compression strength and drop strength of the coal
briquettes are increased. Thus, cold strength of the coal briquettes can be
improved by increasing the amount of solid content included in the sugarcane
syrup. In addition, compared to the coal briquette left for about 1 hour at a
room temperature, the coal briquette dried for about 15 minutes at 80°C has
more excellent cold strength. This is because that moisture included in the
coal briquette is evaporated such that the cold strength of the coal briquette is
improved.
Experiment result of coal briquette manufacturing using sugarcane syrup
and low-grade coal
Experimental Example 23
Coal briquettes were manufactured by mixing 2.7 parts by weight of
CaO and 10 parts by weight of a solution of sugarcane syrup 78% with respect
to 100 parts by weight of pulverized coal that include 20 wt% of thermal coal
43
and 80 wt% of weak corking coal. The remaining experiment processes were
the same as Experimental Example 8.
Experimental Example 24
Coal briquettes were manufactured by mixing 2.7 parts by weight of
CaO and 10 parts by weight of a solution of sugarcane syrup 78% with respect
to 100 parts by weight of pulverized coal that include 50 wt% of thermal coal
and 50 wt% of weak corking coal. The remaining experiment processes were
the same as Experimental Example 23.
Experimental Example 25
Coal briquettes were manufactured by mixing 2.7 parts by weight of
CaO and 7 parts by weight of a solution of sugarcane syrup 78% with respect to
100 parts by weight of pulverized coal that include 50 wt% of thermal coal and
50 wt% of weak corking coal. The remaining experiment processes were the
same as Experimental Example 23.
Comparative Example 3
Coal briquettes were manufactured by mixing 2.7 parts by weight of
CaO and 10 parts by weight of molasses with respect to 100 parts by weight of
pulverized coal that include 20 wt% of thermal coal and 80 wt% of weak corking
coal. The remaining experiment processes were the same as Experimental
Example 23.
Comparative Example 4
Coal briquettes were manufactured by mixing 2.7 parts by weight of
CaO and 10 parts by weight of molasses with respect to 100 parts by weight of
pulverized coal that include 50 wt% of thermal coal and 50 wt% of weak corking
44
coal. The remaining experiment processes were the same as Experimental
Example 23.
Experiment result of manufacturing coal briquette using sugarcane syrup
and low-grade coal
Compression strength, drop strength, and hot strength of coal briquettes
manufactured according to the above-stated Experimental Example 23 to
Experimental Example 25, Comparative Example 2, and Comparative Example
3 were measured. The experiment result is shown in Table 8.
(Table 8)
Experimental
example
Cold strength Hot strength
Compression strength Drop
strength
HTS10 HTS13 HTS16
Compression
strength
Deviation
Experimental
example 23
80 1 99 74 33 4
Experimental
example 24
80 1 99 74 33 4
Experimental
example 25
50 2 90 70 27 3
Comparative
example 2
45 3 80 71 17 2
Comparative
example 3
40 3 80 65 13 0
45
As shown in Table 8, coal briquettes manufactured according to
Experimental Example 23 to Experimental Example 25 were relatively superior
to coal briquettes manufactured according to Comparative Example 2 and
Comparative Example 3 in cold strength. In addition, coal briquettes
manufactured according to Experimental Example 23 to Experimental Example
25 were relatively superior to coal briquettes manufactured according to
Comparative Example 2 and Comparative Example 3 in hot strength.
Therefore, although low-grade coal is used, coal briquette having excellent
characteristic can be manufactured by using sugarcane syrup.
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
arrangements included within the spirit and scope of the appended claims.
46
WHAT IS CLAIMED IS:
1. A method for manufacturing coal briquettes being charged into a
dome portion of a melter-gasifier and then quickly heated therein in a molten
iron manufacturing apparatus that includes the melter-gasifier into which
reduced iron is charged and a reducing furnace connected with the meltergasifier
and providing the reduced iron, comprising:
providing pulverized coal;
providing a raw sugar binder of 0 to 10 parts by weight with respect to
100 parts by weight of the pulverized coal;
providing a mixture by adding the raw sugar binder to the pulverized
coal; and
providing coal briquettes by shaping the mixture.
2. The method for manufacturing the coal briquettes of claim 1,
wherein, in the providing the raw sugar binder, the raw sugar binder is provided
as a raw sugar solution, and the raw sugar solution includes raw sugar at about
35 wt% to about 85 wt%.
3. The method for manufacturing the coal briquettes of claim 2,
wherein the raw sugar solution includes raw sugar at about 65 wt% to about 85
wt%.
4. The method for manufacturing the coal briquettes of claim 1,
47
wherein the providing the raw sugar binder comprises:
crushing sugarcane while injecting water;
providing sugarcane juice by juicing the crushed sugarcane; and
providing sugarcane syrup by removing impurities from the sugarcane
juice and concentrating the sugarcane juice.
5. The method for manufacturing the coal briquettes of claim 4,
wherein, in the providing the sugarcane juice, the amount of solid content
included in the sugarcane juice is about 10 wt% to about 30 wt%.
6. The method for manufacturing the coal briquettes of claim 4,
wherein, in the providing the sugarcane syrup as the raw sugar binder, the
amount of solid content included in the sugarcane juice is about 50 wt% to 90
wt%.
7. The method for manufacturing the coal briquette of claim 6,
wherein the amount of solid content included in the sugarcane syrup is about 65
wt% to about 85 wt%.
8. The method for manufacturing the coal briquettes of claim 7,
wherein the amount of solid content included in the sugarcane syrup is about 70
wt% to about 78 wt%.
9. The method for manufacturing the coal briquettes of claim 4,
48
further comprising adding paraffin to the sugarcane syrup, wherein the amount
of paraffin is greater than 0 and less than 1 wt% with respect to the amount of
sugarcane syrup.
10. The method for manufacturing the coal briquettes of claim 4,
wherein, in the providing the mixture, the mixture is mixed for about 5 minutes
to about 7 minutes at a temperature of about 50°C to about 100°C.
11. The method for manufacturing the coal briquettes of claim 4,
wherein, in the providing the sugarcane syrup as the raw sugar binder, the
amount of total reducing sugar included in the sugarcane syrup is about 65wt%
to about 90wt%.
12. The method for manufacturing the coal briquettes of claim 4,
wherein, in the providing the pulverized coal, the pulverized coal is at least one
selected from a group consisting of thermal coal, weak coking coal, brown coal,
and anthracite coal.
13. The method for manufacturing the coal briquettes of claim 1,
wherein the providing the raw sugar binder comprises:
providing a melted solution by melting the raw sugar with steam of about
70°C to about 120°C; and
providing the raw sugar binder as a raw sugar solution by adding water
to the melted solution and agitating the water-added melted solution at a
49
temperature about 60°C to about 70°C.
14. The method for manufacturing the coal briquettes of claim 1,
further comprising providing at least one hardener selected from a group
consisting of quicklime, slaked lime, calcium carbonate, cement, bentonite, clay,
silica, dolomite, phosphoric acid, and sulfuric acid,
wherein, in the providing the mixture, the hardener is added more to the
pulverized coal and the amount of hardener with respect to 100 parts by weight
of the pulverized coal is 1 part by weight to 6 parts by weight.
15. The method for manufacturing the coal briquettes of claim 1,
wherein, in the providing the raw sugar binder, a ratio of solid content with
respect to the amount of total reducing sugar included in the raw sugar binder is
greater than 1 and less than 1.2.
16. The method for manufacturing the coal briquettes of claim 1,
wherein, in the providing the raw sugar binder, the raw sugar binder comprises
at least one selected from a group consisting of sucrose, glucose, and fructose.
17. The method for manufacturing the coal briquettes of claim 16,
wherein the raw sugar binder comprises the sucrose and the amount of sucrose
with respect to 100 parts by weight of the pulverized coal is greater than 0 and
less than 4 parts by weight.
50
18. The method for manufacturing the coal briquettes of claim 17,
wherein the amount of sucrose is 2 parts by weight to 4 parts by weight.
19. The method for manufacturing the coal briquettes of claim 16,
wherein the raw sugar binder comprises the glucose and the amount of glucose
with respect to 100 parts by weight of the pulverized coal is greater than 0 and
less than 4 parts by weight.
20. The method for manufacturing the coal briquettes of claim 19,
wherein the amount of glucose is 2 parts by weight to 4 parts by weight.
21. The method for manufacturing the coal briquettes of claim 16,
wherein the raw sugar binder comprises the fructose and the amount of fructose
with respect to 100 parts by the pulverized coal is greater than 0 and less than 4
parts by weight.
22. The method for manufacturing the coal briquettes of claim 21,
wherein the amount of fructose is 2 parts by weight to 4 parts by weight.
23. The method for manufacturing the coal briquettes of claim 1,
wherein the reducing furnace is a fluidized bed reduction furnace or a packed
bed reduction furnace.
24. The method for manufacturing the coal briquettes of claim 1,
51
wherein, in the providing the raw sugar binder, the raw sugar binder is provided
as a raw sugar solution and the amount of raw sugar solution with respect to
100 parts by weight of the pulverized coal is 3 parts by weight to 10 parts by
weight.
25. The method for manufacturing the coal briquettes of claim 24,
wherein the amount of raw sugar solution is 6 parts by weight to 10 parts by
weight.
26. The method for manufacturing the coal briquettes of claim 25,
wherein the amount of raw sugar solution is 8 parts by weight to 10 parts by
weight.
27. The method for manufacturing the coal briquettes of claim 24,
wherein the amount of sucrose included in the raw sugar solution is 45 wt% to
75 wt%.
28. The method for manufacturing the coal briquettes of claim 1,
wherein, in the providing the raw sugar binder, viscosity of the raw sugar binder
is 100cp to 10,000cp.
29. The method for manufacturing the coal briquettes of claim 1,
wherein, in the providing the pulverized coal, the amount of moisture in the
pulverized is 3 wt% to 12 wt%.
52
30. Coal briquette being charged into a dome portion of a meltergasifier
and then quickly heated therein in a molten iron manufacturing
apparatus that includes the melter-gasifier into which reduced iron is charged
and a reducing furnace connected with the melter-gasifier and providing the
reduced iron,
wherein the coal briquette comprises pulverized coal and a raw sugar
binder,
the amount of raw sugar binder with respect to 100 parts by weight of
pulverized coal is greater than 0 and less than 10 parts by weight, and the raw
sugar binder comprises at least one selected from a group consisting of sucrose,
glucose, and fructose.
31. The coal briquette of claim 30, wherein, when the raw sugar
binder comprises sucrose, the amount of sucrose is greater than 0 and less
than 4 parts by weight with respect to 100 parts by weight of the pulverized coal.
32. The coal briquette of claim 31, wherein the amount of sucrose is
2 parts by weight to 4 parts by weight.
33. The coal briquette of claim 30, wherein, when the raw sugar
binder comprises fructose, the amount of fructose is greater than 0 and less
than 4parts by weight with respect to 100 parts by weight of the pulverized coal.
53
34. The coal briquette of claim 33, wherein the amount of fructose is
2 parts by weight to 4parts by weight.
35. The coal briquette of claim 30, further comprising at least one
hardener selected from a group consisting of quicklime, slaked lime, calcium
carbonate, cement, bentonite, clay, silica, dolomite, phosphoric acid, and
sulfuric acid, wherein the amount of hardener is 0.1 part by weight to 6 parts by
weight with respect to 100 parts by weight of the pulverized coal.
36. The coal briquette of claim 30, wherein the amount of solid
content included in the raw sugar is 16 wt% to 96 wt%.
37. The coal briquette of claim 36, wherein the amount of solid
content is 78 wt% to 96 wt%.