U.S. patent application number 14/654907 was filed with the patent office on 2015-12-03 for coal bruquette manufacturing method and coal bruquette manufacturing apparatus.
This patent application is currently assigned to POSCO. The applicant listed for this patent is POSCO. Invention is credited to Nam-Hwan HEO, Jin Ho RYOU, Chang-Il SON, Sang-Ho YI.
Application Number | 20150344800 14/654907 |
Document ID | / |
Family ID | 51021615 |
Filed Date | 2015-12-03 |
United States Patent
Application |
20150344800 |
Kind Code |
A1 |
SON; Chang-Il ; et
al. |
December 3, 2015 |
COAL BRUQUETTE MANUFACTURING METHOD AND COAL BRUQUETTE
MANUFACTURING APPARATUS
Abstract
A method and an apparatus for manufacturing coal briquettes
capable of implementing excellent cold strength and hot strength by
separating and crushing coal per each kind of coals are provided.
In the manufacturing method of coal briquettes, the coal briquettes
are charged into a dome part of a melter-gasifier to be rapidly
heated in a manufacturing apparatus of molten iron including i) a
melter-gasifier in which reduced iron is charged, and ii) a
reducing furnace connected to the melter-gasifier and providing the
reduced iron. The manufacturing method of coal briquettes includes:
i) providing a plurality of kinds of coal; ii) storing the
plurality of kinds of coal, respectively; iii) providing powdered
coals by crushing the plurality of kinds of coal, respectively; iv)
providing mixtures by mixing the powdered coal, a hardening agent,
and a binder; and v) providing coal briquettes by molding the
mixture.
Inventors: |
SON; Chang-Il; (Pohang-si,
KR) ; HEO; Nam-Hwan; (Pohang-si, KR) ; RYOU;
Jin Ho; (Pohang-si, KR) ; YI; Sang-Ho;
(Pohang-si, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
POSCO |
Gyeongsangbuk-do |
|
KR |
|
|
Assignee: |
POSCO
Pohang-si, Gyeongsangbuk-do
KR
|
Family ID: |
51021615 |
Appl. No.: |
14/654907 |
Filed: |
December 12, 2013 |
PCT Filed: |
December 12, 2013 |
PCT NO: |
PCT/KR2013/011550 |
371 Date: |
June 23, 2015 |
Current U.S.
Class: |
44/550 ; 44/635;
44/636 |
Current CPC
Class: |
C21B 13/0046 20130101;
C21B 13/0033 20130101; C10L 2290/32 20130101; C10L 2290/28
20130101; C10L 5/26 20130101; C10L 2290/08 20130101; C21B 13/002
20130101; C21B 13/143 20130101; C10L 5/361 20130101; C10L 2290/24
20130101; C10L 5/10 20130101 |
International
Class: |
C10L 5/10 20060101
C10L005/10; C10L 5/26 20060101 C10L005/26; C10L 5/36 20060101
C10L005/36 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 26, 2012 |
KR |
10-2012-0153589 |
Claims
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 including a melter-gasifier into
which reduced iron is charged, and a reducing furnace connected to
the melter-gasifier and providing the reduced iron, the method
comprising: providing a plurality of kinds of coal; storing the
plurality of kinds of coal, respectively; providing powdered coals
by crushing the plurality of kinds of coal, respectively; providing
mixtures by mixing the powdered coal, a hardening agent, and a
binder; and providing coal briquettes by molding the mixtures.
2. The method of claim 1 further comprising drying the plurality of
kinds of powdered coals together.
3. The method of claim 2, wherein a water standard deviation of the
plurality of kinds of powdered coals is 0.3 or less.
4. The method of claim 1, wherein, in the providing of the
plurality of kinds of coal, among the plurality of kinds of coal, a
plurality of kinds of coal having a difference between Hardgrove
Crushability Indexes (HGIs) of 10 or less are mixed and provided
together.
5. The method of claim 4, wherein the difference between the HGIs
among the plurality of kinds of coal is 5 or less.
6. The method of claim 1, wherein the providing of the mixture
comprises: uniformly mixing the powdered coals, and providing and
mixing the binder and the hardening agent with the uniformly mixed
powdered coal.
7. The method of claim 1, wherein in the providing of the powdered
coals, a grain size of the powdered coals is greater than 0 mm and
is 5 mm or less.
8. The method of claim 7, wherein the grain size of the powdered
coals is 1 mm to 3 mm.
9. The method of claim 1, wherein in the providing of the powdered
coals, the plurality of kinds of coals include first coal and
second coal, and a crushing time of the first coal is different
from the crushing time of the second coal.
10. The method of claim 9, wherein the crushing time of the first
coal is greater than that of the second coal, and a caking property
of the first coal is smaller than that of the second coal.
11. An apparatus for manufacturing coal briquettes, comprising: a
plurality of coal storage tanks storing a plurality of kinds of
coal; a plurality of crushers connected to the plurality of coal
storage tanks to provide powdered coals by crushing the plurality
of kinds of coals, respectively; a binder storage tank storing a
binder; a hardening agent storage tank storing a hardening agent; a
mixer providing mixtures by mixing the powdered coals provided from
the plurality of crushers, the binder provided from the binder
storage tank, and the hardening agent provided from the hardening
agent storage tank; and a molding machine molding the mixture by
receiving the mixture from the mixer.
12. The apparatus of claim 11 further comprising a drier connected
directly with the plurality of crushers to dry the powdered coals
together.
Description
TECHNICAL FIELD
[0001] The present invention relates to a method and an apparatus
for manufacturing coal briquettes. In more detail, the present
invention relates to a method and an apparatus for manufacturing
coal briquettes capable of implementing excellent cold strength and
hot strength by separating and crushing coal per each kind of
coals.
BACKGROUND ART
[0002] In a smelting reduction iron-making method, a reducing
furnace for reducing iron ores and a melter-gasifier for 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
is 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 coal-packed bed. After oxygen is
injected through a tuyere installed in the melter-gasifier, the
coal-packed bed is combusted to generate combustion gas. The
combustion gas is transformed into reducing gas at a high
temperature while increasing a temperature through the coal-packed
bed. The hot reducing gas is discharged outside the melter-gasifier
to be supplied to the reducing furnace as the reducing gas.
[0003] In the case of using the coal briquettes, there is a need to
utilize a manufacturing process of molten iron by increasing yield
of molten iron and reducing a fuel ratio. To this end,
differentiation capacity in the melter-gasifier of the coal
briquettes is reduced and thus the coal briquettes in the
melter-gasifier need to be maintained with a large grain size. In
this case, reaction efficiency and heat-transfer efficiency may be
increased by ensuring permeability and flow so that gas and liquid
smoothly pass through the melter-gasifier. Further, due to
differentiation, a generation amount of fine powder which is not
efficiently used during manufacture of molten iron may be reduced.
There is a limit to reduce the generation amount of fine powder by
combination of various coal kinds.
DISCLOSURE
Technical Problem
[0004] The present invention has been made in an effort to provide
a manufacturing method of coal briquettes having advantage of
implementing excellent cold strength and hot strength by separating
and crushing coal for each of coal kinds. The present invention has
been made in an effort to provide a manufacturing apparatus of coal
briquettes having an advantage of implementing excellent cold
strength and hot strength by separating and crushing coal per each
kind of coals.
Technical Solution
[0005] An exemplary embodiment of the present invention provides 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 including a melter-gasifier into which
reduced iron is charged, and a reducing furnace connected to the
melter-gasifier and providing the reduced iron. The method includes
i) providing a plurality of kinds of coal; ii) storing the
plurality of kinds of coal, respectively; iii) providing powdered
coals by crushing the plurality of kinds of coal, respectively; iv)
providing mixtures by mixing the powdered coal, a hardening agent,
and a binder; and v) providing coal briquettes by molding the
mixtures.
[0006] A method for manufacturing coal briquettes according to an
exemplary embodiment of the present invention may include drying
the plurality of kinds of powdered coals together. A water standard
deviation of the plurality of kinds of powdered coals may be 0.3 or
less. In the providing of the plurality of kinds of coal, among the
plurality of kinds of coal, a plurality of kinds of coal having a
difference between Hardgrove Crushability Indexes (HGIs) of 10 or
less may be mixed and provided together. The difference between the
HGIs among the plurality of kinds of coal may be 5 or less.
[0007] The providing of the mixture may include i) uniformly mixing
the powdered coals, and ii) providing and mixing the binder and the
hardening agent with the uniformly mixed powdered coal. In the
providing of the powdered coals, a grain size of the powdered coals
may be greater than 0 mm and may be 5 mm or less. The grain size of
the powdered coals may be 1 mm to 3 mm.
[0008] In the providing of the powdered coals, the plurality of
kinds of coals may include first coal and second coal, and a
crushing time of the first coal may be different from the crushing
time of the second coal. The crushing time of the first coal may be
greater than that of the second coal, and a caking property of the
first coal is smaller than that of the second coal.
[0009] An apparatus for manufacturing coal briquettes according to
an embodiment of the present invention includes i) a plurality of
coal storage tanks storing a plurality of kinds of coal; ii) a
plurality of crushers connected to the plurality of coal storage
tanks to provide powdered coals by crushing the plurality of kinds
of coals, respectively; iii) a binder storage tank storing a
binder; iv) a hardening agent storage tank storing a hardening
agent; v) a mixer providing mixtures by mixing the powdered coals
provided from the plurality of crushers, the binder provided from
the binder storage tank, and the hardening agent provided from the
hardening agent storage tank; and vi) a molding machine molding the
mixture by receiving the mixture from the mixer.
Advantageous Effects
[0010] Since different kinds of coal are separately crushed, and
dried per each kinds of coals to manufacture the coal briquettes,
cold strength and hot strength thereof may be improved.
Accordingly, process efficiency and fuel ratio may be improved in a
manufacturing process of molten iron by increasing the size and the
strength of chars obtained by drastically pyrolyzing the coal
briquettes in the melter-gasifier. Further, low-priced coal having
difficulty in crushing may be used as raw materials for coal
briquettes and an amount of the binder may be reduced.
DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a schematic flowchart of a manufacturing method of
coal briquettes according to an exemplary embodiment of the present
invention.
[0012] FIG. 2 is a schematic diagram of a manufacturing apparatus
of coal briquettes according to another exemplary embodiment of the
present invention.
[0013] FIG. 3 is a schematic diagram of a manufacturing apparatus
of molten iron connected to the manufacturing apparatus of coal
briquettes of FIG. 2.
[0014] FIG. 4 is a schematic diagram of another manufacturing
apparatus of molten iron connected to the manufacturing apparatus
of coal briquettes of FIG. 2.
EXPLANATION OF REFERENCE CHARACTERS
[0015] 10: Coal storage tank [0016] 20: Crusher [0017] 40: Binder
storage tank [0018] 50: Hardening agent storage tank [0019] 60:
Mixer [0020] 70: Molding machine [0021] 85: Crusher [0022] 90:
Drier [0023] 92: Mixed coal storage tank [0024] 94: Collected coal
storage tank [0025] 100: Apparatus for manufacturing coal
briquettes [0026] 200, 300: Apparatus for manufacturing molten iron
[0027] 210: Melter-gasifier [0028] 220: Reducing furnace [0029]
230: Tuyere [0030] 310: Fluidized-bed reducing furnace [0031] 320:
Reduced iron compression device [0032] 330: Compacted irons storage
tank [0033] 805: Separator [0034] 2101: Dome part
MODE FOR INVENTION
[0035] Terms used herein 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 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 section within the scope of the present invention.
[0036] 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 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 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 technical documents and the contents that
are disclosed currently, but are not to be interpreted as the ideal
or overly official meaning unless so defined.
[0037] The term "HGI" to be used below is used an index
representing resistance of coal for crushing as a Hardgrove
Crushability Index. For example, in the HGI, 50 g of a coal sample
prepared with a predetermined size is put in a crushing unit, the
unit is processed at a predetermined pressure by a standard
rotation number, the coal sample is crushed by a steel ball in the
unit, and coal particles are divided, and an amount of the coal of
less than a predetermined size is recorded and converted to an HGI
value.
[0038] The present invention will be described more fully
hereinafter with reference to the accompanying drawings, in which
exemplary embodiments of the invention are illustrated. 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.
[0039] FIG. 1 schematically illustrates a flowchart of a
manufacturing method of coal briquettes according to an exemplary
embodiment of the present invention. The manufacturing method of
coal briquettes in FIG. 1 is just to exemplify the present
invention, and the present invention is not limited thereto.
Accordingly, the manufacturing method of coal briquettes may be
variously modified.
[0040] As illustrated in FIG. 1, the manufacturing method of coal
briquettes includes providing a plurality of kinds of coal (S10),
storing the plurality of kinds of coal, respectively (S20),
crushing the plurality of kinds of coal, respectively (S30),
providing mixtures by mixing the crushed coal, a hardening agent,
and a binder (S40), and providing coal briquettes by molding the
mixtures (S50). In addition, if necessary, the manufacturing method
of coal briquettes may further include other processes.
[0041] First, in step S10, the plurality of kinds of coal are
provided. As a coal required for manufacturing the coal briquettes,
for example, anthracite coal, coking coal, semi-anthracite coal,
weak coking coal, and the like may be used. The weak coking coal
may include a large amount of volatile matter. Meanwhile, although
not illustrated in FIG. 1, in order to improve the quality of
molten iron, coal for quality control may be mixed with powdered
coals. Here, as the coal for quality control, coal having
reflectance of a predetermined value or more may be used.
[0042] A grain-size distribution range of the plurality of kinds of
coal is very wide as being more than 0 and 50 mm or less.
Meanwhile, regarding the coal, a Hardgrove Crushability Index (HGI)
varies according to a carbonization degree. Brown coal or
sub-bituminous coal having a low carbonization degree have a low
HGI, bituminous coal have a high HGI, and anthracite coal having
the highest carbonization degree have a low HGI again.
[0043] In addition, in step S20, the plurality of kinds of coal are
separated to be stored, respectively. In the case of mixing and
storing the plurality of kinds of coal together, due to a
difference in grain size and a moisture, the quality of the coal
briquettes has negatively influenced on a subsequent process for
manufacturing the coal briquettes. Accordingly, the plurality of
kinds of coal are separated from each other to be separately
stored.
[0044] Next, in step S30, the plurality of kinds of coal is
separately crushed to provide powdered coals. That is, the
plurality of kinds of coal are separately divided and crushed. For
example, the plurality of kinds of coal may be crushed to be
controlled with average grain size to be 5 mm or less. When the
average grain size of the plurality of kinds of coal is greater
than 5 mm, since it is difficult to uniformly mix the plurality of
kinds of coal in a subsequent process, the quality of the coal
briquettes may be deteriorated. Accordingly, the average grain size
of the plurality of kinds of coal is controlled in the
aforementioned range. Preferably, the average grain size of the
coal may be controlled to 1 mm to 3 mm.
[0045] The plurality of kinds of coal may have different HGIs. For
example, a difference between HGIs of the plurality of kinds of
coal may be 10 or less. When the difference between HGIs is very
large, it is inappropriate for use as a coal raw material for
manufacturing the coal briquettes. Accordingly, the difference
between HGIs is controlled in the aforementioned range. Preferably,
the difference between HGIs may be 5 or less.
[0046] Meanwhile, since the plurality of kinds of coal having
different HGIs are separately crushed, a crushing time of the
plurality of kinds of coal may be different from each other. That
is, since coal having a low HGI is not crushed well as particles,
the crushing time is set to be longer. On the contrary, since coal
having a high HGI is crushed well, the crushing time may be
reduced. Meanwhile, since coal having a high caking property is
crushed well, as the caking property is higher, the crushing time
is set to be longer.
[0047] In a conventional method, various kinds of coal were dried
together, and then crushed together as well. In this case, since a
grain size of coal is changed according to a difference in strength
between the coal kinds, a grain-size distribution of mixed coal in
which coal are collected is increased too much. Accordingly, a
water deviation of mixed coal is large, it is difficult to manage a
grain size due to a wide grain-size distribution caused by
different HGIs, and it is difficult to control a grain size when a
mixing ratio of coal per each kind of coals is changed. As a
result, this may have a negative influence on hot strength and cold
strength of coal briquettes manufactured in a subsequent process.
On the contrary, in an exemplary embodiment of the present
invention, since different kinds of coal are separately crushed and
then mixed together, the grain-size distribution decreases. Here,
the crushing of the coal is performed by changing a capacity of a
crusher, a crushing condition, a crushing speed, and the like. As a
result, since the water deviation of the mixed coal is small and
the mixed coal has a uniform grain size, coal briquettes having an
excellent characteristic may be manufactured.
[0048] Meanwhile, although not illustrated in FIG. 1, mixed coals
made by mixing separately crushed coals together may be dried. In
this case, since the crushed coals having a constant grain size are
dried, the water deviation of the mixed coal may be minimized.
Accordingly, since a water amount and a water deviation of the
mixed coal may be properly controlled, the quality of coal
briquettes may be further improved. For example, a water standard
deviation of the mixed coals in which powdered coals are mixed may
be controlled to be 0.3 or less. When the water standard deviation
of the mixed coals is too large, the water amount included in the
mixed coal is not constant and thus the quality of coal briquettes
deteriorates.
[0049] In a conventional method, a water amount of the coal after
drying the coal was automatically controlled to become a target
value. In this case, for automatic control, there was a need to
consider many parameters such as a dry amount of coal, a drying
temperature of a coal drier, an air flow, and a water amount of
coal before drying. Further, in the case of measuring the water, in
order to enhance accuracy of the measurement value, a large sample
for measuring water is required and the sample needs to be
uniformly collected. Then, it becomes more difficult to
mechanically collect and dry the sample for automatically measuring
the water of the coal. Accordingly, since it is difficult to
control a water variation of coal before drying the coal, the
automatic water control is impossible. Unlike this, in the
exemplary embodiment of the present invention, since the coal is
crushed and then dried after the grain sizes are uniformalized, the
drying process of the coal is simplified.
[0050] Next, in step S40, mixtures are provided by mixing the
crushed coals, a hardening agent, and a binder. Here, the crushed
coals, graphite, the hardening agent, and the binder may be mixed
in a random order or specific raw materials may be added first. For
example, after the crushed coal and the binder are first mixed, the
hardening agent may be mixed therein. Alternatively, after the
crushed coal and the hardening agent are mixed, the binder may be
mixed therein.
[0051] As the hardening agent, quicklime, slaked lime, a metal
oxide, fly ash, clay, a surface active agent, a cationic resin, an
accelerator, fiber, phosphate, sludge, waste plastics, waste
lubricating oil, waste toner, graphite, activated carbon, or the
like may be used. Further, as the binder, molasses, starch, sugar,
a polymer resin, pitch, tar, bitumen, oil, cement, asphalt, water
glass, or the like may be used. For example, by using molasses as
the binder and quicklime as the hardening agent, the cold strength
of coal briquettes may be largely increased by a saccharate bond
when the coal briquettes are manufactured.
[0052] Meanwhile, in step S40, the different kinds of powdered
coals are first uniformly mixed and then the binder and the
hardening agent are provided to provide the mixtures. That is,
since the powdered coals include various kinds of coal, when the
kinds of powdered coals are not uniformly mixed, the quality of
coal briquettes may be deteriorated. Accordingly, before supplying
the binder and the hardening agent to the powdered coal, powdered
coals are uniformly mixed.
[0053] Finally, in step S50, the coal briquettes are provided by
molding the mixture. For example, the coal briquettes may be
manufactured by continuously compressing the mixture by using a
molding machine including a pair of rollers.
[0054] FIG. 2 schematically illustrates an apparatus for
manufacturing coal briquettes 100 according to another exemplary
embodiment of the present invention. The apparatus for
manufacturing coal briquettes 100 in FIG. 2 is just to exemplify
the present invention, and the present invention is not limited
thereto. Accordingly, a structure of the apparatus for
manufacturing coal briquettes 100 may be variously modified.
[0055] As illustrated in FIG. 2, the apparatus for manufacturing
coal briquettes 100 includes a coal storage tank 10, a crusher 20,
a binder storage tank 40, a hardening agent storage tank 50, a
mixer 60, and a molding machine 70. In addition, the apparatus for
manufacturing coal briquettes 100 further includes a dryer 90, a
mixed coal storage tank 92, a collected coal storage tank 94, and a
separator 805. If necessary, the apparatus for manufacturing coal
briquettes 100 may further include other devices. Since a detailed
structure and an operation method of respective devices included in
the apparatus for manufacturing coal briquettes 100 of FIG. 2 can
be easily understood by those skilled in the art, the detailed
description is omitted.
[0056] A plurality of coal storage tanks 10 separately store a
plurality of kinds of coal, respectively. For example, in order to
improve the quality of coal briquettes in addition to the coal used
as a raw material of coal briquettes, coal for controlling quality
may be used. Accordingly, in order to mix an appropriate amount of
coal for controlling quality according to an amount of the coal
used as a raw material, the plurality of coal storage tanks 10 are
separately installed.
[0057] A plurality of crushers 20 are connected to the plurality of
coal storage tanks 10, respectively. The plurality of crushers 20
receive different kinds of coal from the plurality of coal storage
tanks 10, respectively, to crush the different kinds of coals. For
example, the coal is crushed to be provided as powdered coals
having a grain size of 8 mm or less. Although not illustrated in
FIG. 2, the crushed powdered coals may be directly provided to the
mixer 60. Further, the crushed powdered coals may be dried and then
supplied to the mixer 60.
[0058] The drier 90 dries the crushed powdered coals together which
are supplied from each crusher 20. Accordingly, a plurality of
kinds of powdered coals are mixed together in the drier 90, dried,
and then may be supplied to the mixer 60.
[0059] As illustrated in FIG. 2, the binder is stored in the binder
storage tank 40. The binder binds the plurality of kinds of
powdered coals with each other to make them in a state suitable for
manufacturing the coal briquettes. The binder storage tank 40 is
connected with the mixer 60 to provide the binder to the mixer
60.
[0060] Meanwhile, the hardening agent is stored in the hardening
agent storage tank 50. The hardening agent is combined with the
powdered coals to harden the coal briquettes and thus the strength
of coal briquettes may be optimized. The hardening agent storage
tank 50 is connected with the mixer 60 to provide the hardening
agent thereto.
[0061] The mixer 60 mixes the powdered coal, the binder, the
hardening agent, and the like with each other to provide the
mixtures for manufacturing the coal briquettes. Before being
supplied to the mixer 60, the plurality of kinds of coal are stored
and pre-mixed in the mixed coal storage tank 92 together and
uniformly mixed with each other in the mixer 60 again. Since the
powdered coals include a plurality of kinds of coals, the powdered
coals are uniformly mixed by driving the mixer 60 in advance before
the binder and the hardening agent are put into the mixer 60. When
the binder and the hardening agent are directly charged into the
mixer 60, the plurality of kinds of powdered coals are not
uniformly mixed and thus the quality of coal briquettes may be
deteriorated. Accordingly, the plurality of kinds of powdered coals
are first mixed in the mixer 60.
[0062] As illustrated in FIG. 2, the molding machine 70 includes a
pair of rolls that rotate in an opposite direction to each other.
The mixtures are compressed by the pair of rolls by supplying them
between the pair of rolls to manufacture the coal briquettes.
Meanwhile, the powdered coals are stored in the collected coal
storage tank 94 by dividing the manufactured coal briquettes
through the separator 805 again. The powdered coals stored in the
collected coal storage tank 94 is re-supplied to the mixer 60 again
to be used as a raw material of the coal briquettes. As a result,
use efficiency of the powdered coals may be improved.
[0063] FIG. 3 schematically illustrates a apparatus for
manufacturing molten iron 200 which is connected to the apparatus
for manufacturing coal briquettes 100 of FIG. 2, and uses the coal
briquettes manufactured by the apparatus for manufacturing coal
briquettes 100. A structure of the 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.
[0064] The apparatus for manufacturing molten iron 200 of FIG. 3
includes a melter-gasifier 210 and a reducing furnace 220. In
addition, if necessary, the apparatus for manufacturing molten iron
200 may include other devices. Iron ore is charged into and reduced
in the reducing furnace 220. The iron ore charged into the reducing
furnace 220 is dried in advance and then prepared as reduced iron
while passing through the reducing furnace 220. The reducing
furnace 220, as a packed-bed reducing furnace, receives the
reducing gas from the melter-gasifier 210 to form a packed bed in
the reducing furnace 220.
[0065] Since the coal briquettes manufactured by the apparatus for
manufacturing coal briquettes 100 of FIG. 2 are charged into the
melter-gasifier 210 of FIG. 3, a coal-packed bed is formed in the
melter-gasifier 210. A dome part 2101 is formed at an upper portion
of the melter-gasifier 210. That is, in the dome part 2101 having a
wider space than another part of the melter-gasifier 210, hot
reducing gas exists. The coal briquettes are charged into the dome
part 2101 of the melter-gasifier 210 and then drastically heated
while falling down to the lower portion of the melter-gasifier 210.
Char generated by a pyrolysis reaction of the coal briquettes moves
downward in the melter-gasifier 210 to exothermically react with
oxygen supplied through a tuyere 230. As a result, the coal
briquettes may be used as a heat source which keeps the
melter-gasifier 210 at a high temperature. Meanwhile, since the
char has permeability, a large amount of gas generated from the
lower portion of the melter-gasifier 210 and reduced iron supplied
from the reducing furnace 220 may more easily and uniformly pass
through the coal-packed bed in the melter-gasifier 210.
[0066] In addition to the aforementioned coal briquettes, if
necessary, lump carbonaceous materials or cokes may be charged into
the melter-gasifier 210. The tuyere 230 is installed at an outer
wall of the melter-gasifier 10 to inject oxygen. Oxygen is injected
to the coal-packed bed to form a raceway. The coal briquettes are
combusted in the raceway to generate reducing gas.
[0067] FIG. 4 schematically illustrates another apparatus for
manufacturing molten iron 300 which is connected to the apparatus
for manufacturing coal briquettes 100 of FIG. 2, and uses the coal
briquettes manufactured by the apparatus for manufacturing coal
briquettes 100. A structure of the apparatus for manufacturing
molten iron 300 in FIG. 4 is just to exemplify the present
invention, and the present invention is not limited thereto.
Accordingly, the apparatus for manufacturing molten iron 300 in
FIG. 4 may be modified in various shapes. Since the structure of
the apparatus for manufacturing molten iron 300 in FIG. 4 is
similar to the structure of the apparatus for manufacturing molten
iron 200 in FIG. 3, like reference numerals refer to like parts,
and the detailed description is omitted.
[0068] As illustrated in FIG. 4, the apparatus for manufacturing
molten iron 300 includes a melter-gasifier 210, a fluidized-bed
reducing furnace 310, a reduced iron compression device 320, and a
compacted irons storage tank 330. The compacted irons storage tank
330 may be omitted.
[0069] The manufactured coal briquettes are charged into the
melter-gasifier 210. The coal briquettes generate reducing gas in
the melter-gasifier 210, and the generated reducing gas is supplied
to a fluidized-bed reducing furnace 310. Fine iron ores are
supplied to the fluidized-bed reducing furnace 310 and manufactured
to be reduced irons while flowing by reducing gas supplied to the
fluidized-bed reducing furnace 310 from the melter-gasifier 210.
The reduced irons are compressed by the apparatus for manufacturing
compacted irons 320 and then stored in the compacted irons storage
tank 50. The compacted irons is supplied from the compacted irons
storage tank 330 to the melter-gasifier 210 to be melted in the
melter-gasifier 210. Since the coal briquettes are charged into the
melter-gasifier 210 to be transformed to char having permeability,
a large amount of gas are generated at a lower portion of the
melter-gasifier 210 and the compacted irons more easily and
uniformly pass through the coal-packed bed in the melter-gasifier
210 to manufacture molten iron with a good quality. Meanwhile,
oxygen is supplied through the tuyere 230 to combust the coal
briquettes.
[0070] 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
Experiment for Evaluating Grain-Size Distribution Change after
Crushing According to an HGI Difference Per Each Kind of Coals
[0071] Coal samples configured by coal A, coal B, and coal C having
a grain size of 5 mm to 20 mm were prepared. Coal A was coking
coal, coal B was weak coking coal of high volatile matter, and coal
C was semi-anthracite coal. The entire amount of coal A, coal B,
and coal C was crushed by using a crusher so that the grain size
became 5 mm or less. In addition, a grain-size distribution was
measured by dividing coal A, coal B, and coal C. The measured
grain-size distribution is represented by the following Table
1.
TABLE-US-00001 TABLE 1 NO Coal HGI 1 Coal A 80 to 90 2 Coal B 50 to
60 3 Coal C 80 to 90
[0072] As listed in Table 1, in an HGI of each coal, coal A and
coal C were 80 to 90 and coal B was 50 to 60. When the HGI value is
large, the crushing is performed well, and when the HGI value is
small, the crushing is not performed well. Accordingly, it was well
known that coal A and coal C were crushed well as compared with
coal B.
[0073] Meanwhile, a grain-size distribution of each coal according
to an HGI difference is listed in the following Table 2. As listed
in Table 2, in coal A and coal C having a high HGI value, a coarse
grain-size ratio of 1 to 5 mm was relatively low as compared with
coal B having a low HGI value. On the contrary, in coal A and coal
C, a fine grain-size ratio of 0.25 mm or less was relatively high
as compared with coal B. Accordingly, when coal A, coal B, and coal
C are mixed together and then crushed, coal A and coal C have a
high possibility to be over-crushed and coal B has a high
possibility to be non-crushed. Accordingly, the grain sizes of coal
A and coal C are relatively decreased, while the grain size of coal
B may be relatively increased. As described above, when the
grain-size distribution characteristic of the crushed powdered
coals is not uniform, an optimal grain-size distribution
characteristic may not be implemented, and thus quality of the coal
briquettes in hot and cold states is deteriorated. Further, when
coal A to coal C were mixed and then crushed, it was difficult to
control the overall grain size.
TABLE-US-00002 TABLE 2 Coal grain-size distribution NO Coal -0.25
mm 0.25 to 0.5 mm 0.5 to 1 mm 1 to 5 mm 1 Coal A 30.6% 14.0% 18.2%
37.2% 2 Coal B 12.1% 11.6% 22.3% 54.0% 3 Coal C 29.2% 14.4% 17.2%
39.2%
Evaluation Experiment of Quality in Cold and Hot States According
to Grain-Size Distribution
[0074] Coal A, coal B, and coal C were prepared. Maximum grain-size
upper limits of coal per each kind of coals were divided into 5 mm,
3 mm, and 1 mm, respectively. Each kind of coal, a binder, and a
hardening agent were mixed at an appropriate ratio and then pressed
by using a roll press at room temperature to manufacture coal
briquettes with a pillow shape with a diameter of 51 mm, a width of
37 mm, and a thickness of 24 mm. The volume of coal briquettes was
25 cm.sup.3, and a compressive strength of coal briquettes was
calculated according to the following Equation 1.
Compressive strength (kgf)=compressive strength by compressive
strength measurer (average value measured 10 times) [Equation
1]
[0075] Table 3 lists a compressive strength of coal briquettes
according to the aforementioned grain-size distribution. As listed
in Table 3, coal A to coal C had the highest compressive strength
when the maximum upper-limit grain size was 3 mm. When pressure was
applied to coal having a layered structure, cracks due to pressure
occurred, and as a result, it is assumed that as the grain size was
increased, the crack was increased and thus the compressive
strength of coal briquettes was regarded to be deteriorated.
TABLE-US-00003 TABLE 3 Maximum upper-limit grain size of coal NO
Coal -5 mm -3 mm -1 mm 1 Coal A 43.2 kgf 49.3 kgf 48.2 kgf 2 Coal B
43.0 kgf 44.2 kgf 44.1 kgf 3 Coal C 44.1 kgf 47.2 kgf 46.5 kgf
[0076] Meanwhile, since an HGI of coal B was lower than HGIs of
coal A and coal C, a ratio of coarse coal was high and coarse coal
had a large influence on the compressive strength. Further, an
arithmetic mean grain size of coal B calculated by the following
Equation 2 was significantly larger than an arithmetic mean grain
size of coal A.
Arithmetic mean grain size (mm)=(weight ratio of grain size of 3 to
5 mm.times.4 mm)+(weight ratio of grain size of 1 to 3 mm.times.2
mm)+(weight ratio of grain size of 1 mm or less.times.0.5 mm)/100
[Equation 2]
In addition, as listed in the following Table 4, it was shown that
a weight of coal briquettes manufactured by coal B was lower than a
weight of those manufactured by coal A and coal C. Accordingly, the
compressive strength of coal B was shown to be little. Considering
the aforementioned view point, in the case of mixing and crushing
coal A to coal C, the grain size of coal B after crushing is
relatively increased, and thus the compressive strength of coal
briquettes is deteriorated. Accordingly, in the case of
manufacturing coal briquettes by separating, crushing, and mixing
coal A to coal C, it could be known that the compressive strength
of coal briquettes may be improved.
TABLE-US-00004 TABLE 4 Specific gravity of coal Grain-size After
crushing Arithmetic briquettes NO coal distribution +3 mm(%)
mean(mm) (g/cm.sup.3) 1 Coal -5 mm 2.7 0.98 1.223 2 A -3 mm 0.0
0.58 1.238 3 -1 mm 0.0 0.31 1.224 4 Coal -5 mm 5.3 1.36 1.211 5 B
-3 mm 0.0 0.75 1.210 6 -1 mm 0.0 0.40 1.205 7 Coal -5 mm 4.1 1.19
1.256 8 C -3 mm 0.0 0.72 1.256 9 -1 mm 0.0 0.37 1.257
Experiment for Effect Influenced by a Strength of Char with
Upper-Limit Grain Size Per Each Kind of Coals
[0077] The coal briquettes manufactured as described above were
completely dried for 24 hours. The coal briquettes were put in a
circular reaction furnace with an inert atmosphere at 1000.degree.
C. and rotated at 10 rpm for 60 minutes. Among chars discharged
from the circular reaction furnace, char having a grain size of 10
mm or more was put in an I drum strength machine and rotated 600
times at 20 rpm for 30 minutes. In addition, a ratio of coarse
chars of 10 mm or more was set as a char strength according to the
following Equation 3.
Char strength (%)=((char weight (g) having grain size of 10 mm or
more after measuring I drum strength/(char weight (g) having grain
size of 10 mm or more before measuring I drum strength).times.100
[Equation 3]
[0078] The char strength according to the upper-limit grain size
difference per each kind of coals is shown in the following Table
5. As listed in Table 5, unlike the aforementioned compressive
strength, the char strength in coal A and coal B was good as the
maximum upper-limit grain size was increased, but the maximum
upper-limit grain size of coal C was decreased, the char strength
of coal C was good.
TABLE-US-00005 TABLE 5 Maximum upper-limit grain size of coal NO
Coal -5 mm -3 mm -1 mm 1 Coal A 46.8% 42.4% 41.0% 2 Coal B 65.6%
64.7% 59.0% 3 Coal C 49.1% 51.5% 54.6%
[0079] As the aforementioned experimental result, the compressive
strength representing quality of coal briquettes in a cold state
and the char stength representing quality of coal briquettes in a
hot state had different characteristics per each kind of coals and
each grain size. Accordingly, in order to manufacture the coal
briquettes having good charateristics of the compressive strength
and the char strength of the coal briquettes, it was determined to
be preferred for various kinds of coal to be separated and crushed
by considering unique coal characteristics such as an HGI and a
grain shape. In order to support the determination, another
experiment was performed as follows.
Experiment According to Process Division
Experimental Example 1
[0080] Coal A, coal B, and coal C were separated, crushed, and
dried per each kind of coals, respectively, to manufacture coal
briquettes. That is, a particle characteristic of coal was
considered by separately crushing coal A, coal B, and coal C, and
the crushed coal A, coal B, and coal C were mixed and dried
together to manufacture the coal briquettes. Coal A, coal B, and
coal C were mixed with each other at a mixing ratio of 40 wt %, 30
wt %, and 30 wt %, respectively. In addition, the compressive
strength and the char strength of the coal briquettes were
measured.
Comparative Example 1
[0081] The same kinds of coal as those coal used in Experimental
Example 1 were mixed, dried, and then crushed together. The rest of
the experimental processes were the same as those of the
aforementioned Experimental Example 1.
[0082] Table 6 exhibits a measuring result of compressive strength
and char strength of the coal briquettes manufactured according to
Experimental Example 1 and Comparative Example 1. As listed in
Table 6, in Experimental Example 1, the compressive strength was
increased by approximately 8.8% and the char strength was increased
by approximately 5.4% as compared with Comparative Example 1.
Accordingly, it could be seen that in the case of using a
separating and crushing process per each kind of coals of
Experimental Example 1 instead of an integral crushing process per
each kind of coals of Comparative Example 1, quality of the coal
briquettes may be improved in a hot and cold state.
TABLE-US-00006 TABLE 6 NO Experimental Example Compressive strength
Char strength 1 Experimental Example 1 47.1 kgf 54.6% 2 Comparative
Example 1 43.3 kgf 51.8%
[0083] Water Deviation Experiment of Coal Briquettes
[0084] Standard deviations were calculated by measuring water
amounts of mixed coal 20 times when the coal briquettes of
Experimental Example 1 and Comparative Example 1 were manufactured
to be compared with each other. Table 7 exhibits water standard
deviations of mixed coal of Experimental Example 1 and Comparative
Example 1 which are compared with each other.
[0085] As listed in Table 7, in Comparative Example 1, the water
standard deviation was 0.43, but in Experimental Example 1, the
water standard deviation was 0.30 which was smaller. The reason is
that when the different kinds of coal are first dried before
crushing like the process of Comparative Example 1, a grain-size
range of the coal injected in the drier was wide as 0 to 50 mm, and
even in the same drying condition, there is a difference in drying
according to a difference in grain size. However, like Experimental
Example 1, when the coal is crushed and then dried, the grain-size
range of the coal is very small as 0 to 5 mm, thereby improving the
water deviation of the mixed coal. Therefore, the coal briquettes
having excellent quality in hot and cold state may be manufactured
by uniformly controlling the water amount included in the mixed
coal.
TABLE-US-00007 TABLE 7 NO Experimental Example Water standard
deviation 1 Experimental Example 1 0.30 2 Comparative Example 1
0.43
[0086] 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.
* * * * *