TECHNICAL FIELD
[0001] The present disclosure relates to an exhaust gas processing apparatus and processing
method, and more particularly, to an exhaust gas processing apparatus and processing
method capable of suppressing or preventing interference between exhaust-gas flows
due to a difference between negative pressures in a plurality of regions of an equipment.
RELATED ART
[0002] The sintered ore is produced by using fine iron ore, limestone, coke, and anthracite
as raw materials and then is loaded into a blast furnace. In a blast furnace process
for production of molten iron, the sintered ore is loaded together with iron ore and
coke into the blast furnace. A sintered ore production process sinters fine iron ore
into a size suitable for blast furnace use. The sintered ore production process involves
preparation of mixture of raw materials and thermal treatment of the mixture into
sintered ore. The latter is usually performed in a sintering machine.
[0003] The process of producing the sintered ore by heat-treating the mixture of raw materials
is performed as follows: the mixture of raw materials is loaded, at a constant height,
onto the sintering truck while the truck is moving in the direction of extension of
the sintering machine. A surface layer of the mixture of raw materials is ignited
by an ignition unit to create a raceway or combustion zone. Using an exhaust gas processing
apparatus, air is forcedly inputted downwardly into the sintering truck to move the
raceway downwardly, thereby sintering the mixture of raw-materials, that is, to produce
the sintered ore. The sintered ore is then crushed and cooled via a crusher and a
cooler provided in an unloading region of the sintering machine. The crushed and cooled
sintered ore is classified into granules of 5 mm to 50 mm suitable for use in the
blast furnace and then is transferred to the blast furnace.
[0004] A sintering exhaust-gas circulation technology for improving function of the sintering
machine and reducing energy was published by Kinsey on AIME in US, 1975. In this publication,
an on-strand cooling sintering machine is proposed, which has a structure in which
a length of the sintering machine is extended and a cooler is added to the sintering
machine. Such a configuration includes a sintering region and a cooling region. Gases
are individually suctioned from the sintering zone and the cooling zone. Thus, an
energy-reducing sintering model was proposed by circulating high-temperature exhaust
gas discharged from the cooling zone into the sintering zone as hot air. Subsequently,
similar studies or patent applications were filed in Japan and Europe during the 1970s
and 1980s.
[0005] When the sintering exhaust-gas circulation technique is applied to the sintering
machine process, the energy required for sintering may be reduced by recycling sensible
heat of the exhaust gas for sintering. After the first oil shock, in Wakayama in Japan,
1984, four-sintering was modified via the on-strand cooling sintering machine, and,
then, air in the cooling section of the sintering machine was recirculated for reuse
as sintering air. Further, in Kyushu and Kashima, the sintering exhaust-gas circulation
technology was used to circulate the exhaust gas from the cooler to the sintering
machine. In NKK in 1991, in order to increase gas suction capacity and thus to improve
productivity of Fukuyama 4-sintering, a second blower was installed, and the exhaust
gas recovered by the second blower was recirculated toward a sintered ore discharge
unit of the sintering machine, thereby to enhance sensible heat recovery ability by
a boiler installed therein, together with increase of the gas suction capacity.
[0006] The above-mentioned approaches aim to reduce the amount of exhaust gas while aiming
to reduce the energy, by transmitting the sensible heat of the exhaust gas to the
sintered layer or the ignition furnace. To this end, the sintering exhaust-gas circulation
technology was applied to the sintering machine process.
[0007] Meanwhile, due to the enforcement of environmental policy regulations, investment
and operating costs for processing equipments for treating sulfuric oxides SOx and
nitride oxides NOx have recently become burden. As a result, steel mills in each country
are responding to greenhouse gas regulations and are reducing energy consumption by
recycling exhaust gas from sintering machines to the maximum extent, together with
reducing the investment cost for pollution-prevention equipments.
[0008] For example, NSC's Kitakyushu 3-sintering in 1992 reduced the amount of exhaust gas
by 28% by improving a sintering machine to reduce the amount of exhaust gas while
maintaining productivity and quality of the sintered ore. In 1994, Lurgi, Germany,
developed EOS (Emission Optimized Sintering) technique and applied it to a Hoogovens
sintering plant in the Netherlands to reduce the exhaust gas amount by about 40%.
These cases are prepared to comply with international environmental regulations, but
the technology thereof is not yet completed.
[0009] In addition, since 1994, NSC's FUTSU process lab, Voest-Alpine in Austria, BHP in
Australia and Centro Sviluppo Materiali (CSM) in Italy have been working to adapt
the sintering process to an environmentally friendly process. Sumitomo Corporation
are studying a two-stage ignition sintering method in which, in an on-strand cooling
sintering machine, the raw-material is loaded individually into upper and lower stages
and the materials in the upper and lower stages are ignited and sintered, wherein
exhaust gas from the upper stage is reused for sintering the material in the lower
stage.
[0010] In order to increase the productivity of the sintered ore, there is an approach to
increase the blower capacity in the exhaust gas processing apparatus to increase the
sintering air volume, and an approach to increase the sintering air volume by enlarging
the firing area of the sintering machine. In this connection, when the blower capacity
of the exhaust gas processing apparatus is increased, a machine for cleaning the exhaust-gas
must further be extended, and, further, the maintenance cost of the exhaust gas processing
apparatus is increased.
[0011] Therefore, POSCO's Pohang 4-sintering has introduced the sintering exhaust-gas circulation
technology. In this connection, to deal with increasing demand of the sintered ore
due to increases in an inner capacity of the blast furnace and the high tapping process,
the firing area of the sintering machine is extended and thus the sintering air flow
volume correspondingly increase. Thus, in order to deal with the sintering air flow
volume increase, a further blower for exhaust-gas circulation was added to the exhaust
gas processing apparatus.
[0012] In this connection, while a position where the ventilation resistance of the sintered
layer is the largest is defined as an exhaust-gas suction position, the added blower
sucks the exhaust gas using a high pressure at the above-defined position, and supplies
the same toward a rear end of the sintered layer where oxygen is relatively less consumed.
Since the exhaust gas sucked into the added blower is circulated toward a top face
of the sintered layer, the total amount of exhaust gas may be maintained constantly.
Therefore, even when the firing area of the Pohang 4-sintering is increased and the
blower is added thereto, the existing structure related to the exhaust-gas cleaning
in the exhaust gas processing apparatus may be used as it is not modified.
(Related Art Document)
(Patent Document)
(Non-Patent Document)
[0014]
(Non-Patent Document 1) F.W. Kinsey, Dravo co., , "Design parameters for strand cooling", AIME, vol.34, Ironmaking
proceeding, p85, (1975)
(Non-Patent Document 2) D. Schlebusch, F. Cappel, "Optimization of pollution control in sinter plant", 6-th
International symposium on agglomeration, p403-408, Nagoya, Japan, (1993)
DISCLOSURE OF PRESENT DISCLOSURE
TECHNICAL PURPOSES
[0015] The present disclosure provides an exhaust gas processing apparatus and method which
may suppress or prevent interference between exhaust-gas flows due to a difference
between negative pressures in a plurality of regions of an equipment.
[0016] The present disclosure provides an exhaust gas processing apparatus and method that
can suppress or prevent interference between exhaust-gas flows of an equipment and
thereby improve process efficiency of the equipment.
TECHNICAL SOLUTIONS
[0017] In accordance with an exemplary embodiment, an exhaust gas processing apparatus includes:
a gas-suction array extending in a traveling direction of a truck and disposed below
the truck which is disposed to move along a plurality of regions while processing
a raw-material, wherein the gas-suction array has an exhaust-gas circulation region
and an exhaust-gas discharging region which are separated from each other; and a gas-blocking
structure disposed at a boundary between the exhaust-gas circulation region and exhaust-gas
discharging region so as to seal the spacing between the gas-suction array and the
truck at the boundary.
[0018] The gas-suction array may include a plurality of wind-boxes arranged along the traveling
direction of the truck, wherein the wind-boxes have respectively upper ends arranged
side by side along the extension of the gas-suction array, wherein the upper ends
are coupled to each other, wherein the gas-blocking structure is disposed on adjacent
upper ends of some of the plurality of wind-boxes adjacent to the boundary between
the exhaust-gas circulation region and the exhaust-gas discharging region, while the
adjacent wind-boxes define the boundary therebetween.
[0019] A gap between a top face of the gas-blocking structure and a bottom face of the truck
at the boundary may be greater than 0 and less than or equal to 100 mm, within a tolerance
range.
[0020] In accordance with another exemplary embodiment, an exhaust gas processing apparatus
includes: a plurality of wind-boxes arranged along a traveling direction of a truck
and disposed below the truck, wherein the truck is disposed to move along a plurality
of regions while processing a raw-material, wherein the plurality of wind-boxes has
an exhaust-gas circulation region and an exhaust-gas discharging region which are
separated from each other, wherein upper ends of some of the plurality of wind-boxes
protrude more upwardly than upper ends of the remainder of the plurality of wind-boxes,
wherein the upper ends of some of the plurality of wind-boxes are adjacent to the
boundary between the exhaust-gas circulation region and exhaust-gas discharging region.
[0021] Some of the plurality of wind-boxes include first and second wind-boxes, and the
first and second wind-boxes define the boundary therebetween, and are disposed in
the exhaust-gas circulation region and exhaust-gas discharging region respectively,
wherein a gap between the upper ends of the first and second wind-boxes and a bottom
face of the truck may be greater than 0 and less than or equal to 100 mm, within a
tolerance range.
[0022] The exhaust gas processing apparatus further includes a gas-blocking structure disposed
at the upper ends of the first wind-box and the second wind-box so as to seal a gap
between the truck and some of the wind-boxes at the boundary.
[0023] The gas-blocking structure may include a gas-blocking body extending in a direction
crossing the traveling direction of the truck; and a flap protruding from the gas-blocking
body in the traveling direction of the truck.
[0024] The flap may extend from at least one of an upper end and a lower portion of the
gas-blocking body or from a portion between the upper and lower portion of the gas-blocking
body. The flap may be disposed in at least one of the exhaust-gas circulation region
and exhaust-gas discharging region. The flap may be disposed in a lower negative pressure
region among the exhaust-gas circulation region and exhaust-gas discharging region.
When a cross-sectional area of an upper end of a wind-box facing the flap is set to
1, an extension length of the flap may be greater than 0 and less than or equal to
2/3.
[0025] The gas-blocking structure may further includes at least one rib formed to protrude
upwards from a top face of the flap. The rib may extend in the traveling direction
of the truck, or the rib may extend in a direction crossing the traveling direction
of the truck. The gas-blocking structure may include a plurality of ribs, wherein
some of the plurality of ribs may extend in the traveling direction of the truck,
while the remainder thereof may extend in a direction crossing the traveling direction
of the truck.
[0026] The gas-blocking structure may further include a tip portion projecting downwardly
in a tilted manner from a distal end of the flap in a direction from the body of the
blocking structure to an end of the flap. When a cross-sectional area of an upper
end of a wind-box facing the flap is set to 1, a sum of extension lengths of the flap
and the tip portion in a traveling direction of the truck may be greater than 0 and
less than or equal to 2/3.
[0027] In accordance with an exemplary embodiment, an exhaust gas processing method includes:
loading a raw-material into a truck and thermally-processing the material in the truck
while moving the truck along a plurality of regions; suctioning downwardly an interior
of the truck using a gas-suction array, wherein the gas-suction array extends in a
traveling direction of the truck and disposed below the truck, wherein the gas-suction
array has an exhaust-gas circulation region and an exhaust-gas discharging region
which are separated from each other; and suppressing exhaust-gas flowing from a lower
negative pressure region among the exhaust-gas circulation region and exhaust-gas
discharging region into a space between the gas-suction array and the truck.
[0028] Suppressing the exhaust-gas from flowing from the lower negative pressure region
into the space may include using a gas-blocking structure disposed at a boundary between
the exhaust-gas circulation region and exhaust-gas discharging region.
ADVANTAGEOUS EFFECTS
[0029] In accordance with the exemplary embodiments of the present disclosure, it is possible
to suppress or prevent interference between exhaust-gas flows due to a difference
between negative pressures in a plurality of regions of an equipment, and thereby
to improve process efficiency of the equipment.
[0030] For example, when the embodiments of the present disclosure is applied to a sintered
ore production process, the gas-blocking structure is disposed on adjacent upper ends
of wind-boxes of the plurality of the wind-boxes arranged in the traveling direction
of the truck, adjacent to the boundary while the adjacent wind-boxes define the boundary
between the exhaust-gas circulation region and the exhaust-gas discharging region.
When the raw material is loaded on the truck which in turn travels along the plurality
of regions while the raw-material is thermally treated, and the gas in the truck is
suctioned downwards, the gas-blocking structure suppresses gas flowing from a lower
negative pressure region among the exhaust-gas circulation region and exhaust-gas
discharging region, through the spacing between the gas-suction array and the truck,
to a higher negative pressure region among the exhaust-gas circulation region and
the exhaust-gas discharging region.
[0031] Or, the upper ends of some of the plurality of wind-boxes arranged in the traveling
direction of the truck protrude more upwardly than upper ends of the remainder of
the plurality of wind-boxes, wherein some of the plurality of wind-boxes are adjacent
to the boundary between the exhaust-gas circulation region and exhaust-gas discharging
region. Further, the gas-blocking structure may be disposed on the adjacent upper
ends of the adjacent wind-boxes. When the raw material is loaded on the truck which
in turn travels along the plurality of regions while the raw-material is thermally
treated, and the gas in the truck is suctioned downwards, the narrowed gap or the
gas-blocking structure may suppress gas flowing from a lower negative pressure region
among the exhaust-gas circulation region and exhaust-gas discharging region, through
the spacing between the gas-suction array and the truck, to a higher negative pressure
region among the exhaust-gas circulation region and an exhaust-gas discharging region.
[0032] Therefore, the exhaust gases respectively in the adjacent wind-boxes in the exhaust-gas
circulation region and exhaust-gas discharging region respectively at the boundary
exhaust-gas circulation region and exhaust-gas discharging region may not interfere
with each other. Thus, exhaust-gas may be prevented from back-flowing from the lower
negative pressure region among the exhaust-gas circulation region and exhaust-gas
discharging region to the higher negative pressure region among the exhaust-gas circulation
region and exhaust-gas discharging region. Therefore, both the circulation-flow and
discharge-flow efficiencies of the exhaust flow can be improved, and the overall exhaust-gas
flow rate can be improved. As a result, the efficiency of the sintered ore generation
process can be improved, and high-quality sintered ore can be produced.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033]
FIG.1 is a schematic diagram of a raw-material processing equipment according to an
embodiment of the present disclosure.
FIG. 2 is a schematic diagram illustrating an exhaust gas processing apparatus according
to an embodiment of the present disclosure.
FIG. 3 is a schematic diagram of a gas-blocking structure according to a first modified
embodiment of the present disclosure.
FIG. 4 is a schematic diagram of a gas-blocking structure according to a second modified
embodiment of the present disclosure.
FIG. 5 is a schematic diagram of a gas-blocking structure according to a third modified
embodiment of the present disclosure.
FIG. 6 is a schematic diagram of a gas-blocking structure according to a fourth modified
embodiment of the present disclosure.
FIG. 7 is a schematic diagram of a gas-blocking structure in accordance with a fifth
modified embodiment of the present disclosure.
FIG. 8 is a schematic diagram of exhaust-gas flow for a gas-suction array according
to a comparison example.
FIG. 9 is a graph illustrating numerical analysis of the exhaust-gas flow in the gas-suction
array according to the embodiments of the present disclosure and the comparison example.
FIG. 10 shows photographs of results of a reduced modeling experiment on the exhaust-gas
flow inside the gas-suction array, according to the comparison example and the embodiment
of the present disclosure.
FIG. 11 shows a table indicating results of the reduced modeling experiment for exhaust-gas
flow in the gas-suction array according to the comparison example and the embodiment
of the present disclosure.
DETAILED DESCRIPTIONS
[0034] Hereinafter, embodiments of the present disclosure will be described in detail with
reference to the accompanying drawings. However, the present disclosure is not limited
to the embodiments described below, but may be embodied in various forms. The embodiments
of the present disclosure may be set forth to allow the descriptions of the present
disclosure to be complete and to inform the skilled person to the art of the scope
of the present disclosure. The drawings may be exaggerated to illustrate the embodiments
of the present disclosure. Like numerals refer to like elements throughout the drawings.
[0035] Among terms used for describing the embodiments of the present disclosure, an 'upper
portion' or 'lower portion" refers to an upper or lower portion of a component. In
addition, 'above' or 'below' is used to indicate a space that directly or indirectly
contacts an upper or lower portion of the component.
[0036] The present disclosure provides an exhaust gas processing apparatus and method configured
to allow flow-interference between circulating flow gas and exhausted flow gas during
exhaust-gas flow in a sintering machine to be suppressed in the sintering machine,
which may otherwise occur due to a difference between negative pressures in a plurality
of regions of an equipment, for example, a difference between negative pressures in
wind-boxes. Hereinafter, embodiments will be described in detail with reference to
a sintered ore producing process at a steelworks. Obviously, the present disclosure
may be equally applied to exhaust-gas flow control of various processing equipments.
[0037] In setting forth the embodiments of the present disclosure, a raw-material processing
equipment according to an embodiment of the present disclosure is first described
so that understanding of the present disclosure is clear. With reference to the raw-material
processing equipment, the exhaust gas processing apparatus and method according to
embodiments of the present disclosure will be described in detail.
[0038] FIG. 1 is a schematic diagram of a raw-material processing equipment to which an
exhaust gas processing apparatus according to an embodiment of the present disclosure
is applied. FIG. 2 is a schematic diagram illustrating a gas-suction array and a gas-blocking
structure of an exhaust gas processing apparatus according to an embodiment of the
present disclosure.
[0039] In addition, FIGS. 3 to 7 are schematic diagrams of modifications of a gas-blocking
structure according to embodiments of the present disclosure. In this connection,
FIG. 3 is a schematic diagram of a gas-blocking structure according to a first modified
embodiment of the present disclosure. FIG. 4 is a schematic diagram of a gas-blocking
structure according to a second modified embodiment of the present disclosure. FIG.
5 is a schematic diagram of a gas-blocking structure according to a third modified
embodiment of the present disclosure. FIG. 6 is a schematic diagram of a gas-blocking
structure according to a fourth modified embodiment of the present disclosure. FIG.
7 is a schematic diagram of a gas-blocking structure in accordance with a fifth modified
embodiment of the present disclosure.
[0040] Referring to FIG. 1, the raw-material processing equipment according to an embodiment
of the present disclosure includes a truck 10, a raw-material hopper 21, an upper-sintered
ore hopper 22, an ignition furnace 30, and an exhaust gas processing apparatus 400.
[0041] The raw-material processing equipment may take a raw material and thermally process
it while sequentially moving it along a plurality of regions. At least a portion of
the exhaust gas generated from the plurality of regions may be circulated in at least
a portion of the plurality of regions. In the context of this description, the raw-material
processing equipment may be a sintering machine. For example, the sintering machine
may be a downward suction type sintering machine having an exhaust-gas recirculation
configuration.
[0042] The truck 10 may be configured to allow the raw material therein to be thermally
processed in the plurality of regions. The raw-material processing equipment includes
a plurality of trucks, which may be continuously arranged and coupled together in
the direction of extension of the raw-material processing equipment. The truck 10
may be configured to run in the arrangement direction of the plurality of regions.
The truck 10 is open at the top thereof and thus is loaded with the raw material within
the interior space in each truck. The inner space of each of these trucks corresponds
to a heat processing space. The raw material may be loaded inside the truck 10.
[0043] A bottom portion 11 of the truck 10 may have a configuration in which elongated bars(grate
bars) are arranged in a grid structure. With this configuration, the inner space of
the truck 10 may gas-communicate with a corresponding wind-box as described later,
whereby the exhaust-gas in the inner space may be sucked downwards via the wind-box.
[0044] An upper end of the raw-material processing equipment may define a convey path of
the truck 10, while a lower portion thereof may define a return path of the truck
10. The truck 10 travels in a first direction along the convey path, and, thus, the
raw material loaded therein is moved in the first direction while being thermally
treated. When the truck enters the return path, the heat treated sintered ore is discharged
into the crushing unit (not shown), and, then, the truck travels along the return
path in a second direction opposite to the first direction, and, then, may be returned
to the convey path.
[0045] The convey path may include a plurality of regions. The plurality of regions includes:
a loading region in which the raw material hopper 21 and the upper-sintered ore hopper
22 are located; an ignition region in which the ignition furnace 30 is located, downstream
of the loading region; and a sintering region downstream of the ignition region. The
loading region, the ignition region, and the sintering region may be sequentially
arranged along the moving direction of the raw material.
[0046] The loading region may be located upstream of the convey path, where the raw material
begins to move in the convey path. In the loading region, the raw material is loaded
in the interior space of the truck 10, thereby forming a raw-material layer in the
interior space of the truck 10. The ignition region is located downstream of the loading
region in the movement direction of the raw material and may extend in the direction
of movement of the raw material. In the ignition region, an upper end (hereinafter,
an upper material layer) of the raw-material layer loaded in the truck 10 is ignited.
[0047] In the sintering region, a raceway is moved from the upper material layer of the
raw material layer loaded on the truck 10 to a lower portion of the raw-material layer
(hereinafter referred to as a 'lower material layer'). This sintering region is a
region for sintering and cooling the raw material layer and is located downstream
of the ignition region in the direction of movement of the raw material. The raw material
in each truck 10 is subjected to thermal treatment while each truck is moving the
raw material sequentially along the loading, ignition and sintering regions, thereby
producing a sintered ore.
[0048] The raw-material hopper 21 receives the raw material therein and is located in the
loading region above the truck 10. The raw-material hopper 21 may be provided with
a loading chute and a drum feeder at the bottom opening thereof and, thus, may load
the raw material within the truck 10. In this connection, before the loading, the
raw material may be subjected to vertical segregation by the hopper 21.
[0049] The raw-material may contain a raw-material for sintered ore production. For example,
the raw-material may have particles of sizes on the order of a few millimeters by
mixing, humidifying, and granulating an iron source, additives, and solid fuel. In
this connection, the iron source is a source with an iron component, and may include
iron ores and fine iron ores. The additive may include limestone as a material containing
calcium carbonate. The solid fuel may include coal-based solid fuels, including coke
powders and anthracite.
[0050] The upper-sintered ore hopper 22 is located in the loading region and upstream of
the raw-material hopper 21 in the direction of movement of the raw material. The upper-sintered
ore may be provided by selecting a sintered ore having a particle size of, for example,
8 mm to 15 mm from the sintered ore. The upper-sintered ore may be loaded into the
interior space of the truck 10 prior to loading the raw material thereto, so that
the raw material is prevented from being attached to the bottom of the truck 10 or
is prevented from passing downwardly through gap defined in the bottom of the truck
10.
[0051] The ignition furnace 30 is spaced apart from the raw-material hopper 21 in the traveling
direction of the truck 10. The ignition furnace 30 may be located above the truck
10. That is, the ignition furnace 30 may be located in the ignition region of the
convey path, downstream of the raw-material hopper 21, in the direction in which the
truck 10 travels. The ignition furnace 30 is configured to inject a flame downwards,
and serves to heat the upper material layer by spraying the flame onto the upper material
layer. In this connection, the flame may ignite the solid fuel contained in the upper
material layer.
[0052] The exhaust gas processing apparatus 400 according to an embodiment of the present
disclosure may be configured to suck downwardly gas from the interior space of the
truck 10 and to circulate at least a portion of the sucked gas between the plurality
of regions while the raw material is heat-treated in the interior space of the truck
10 while each truck is moving along the plurality of regions.
[0053] Referring to FIG. 1 and FIG. 2, the exhaust gas processing apparatus 400 according
to an embodiment of the present disclosure may include a gas-blocking structure 413,
a gas-suction array, a gas ventilation pipe 420, an exhaust-gas circulation mechanism,
and an exhaust-gas discharging mechanism.
[0054] The gas-suction array may be disposed on the bottom of the truck 10 and extend along
the direction of travel of the trucks of the truck 10. For example, the gas-suction
array may extend in the traveling direction of the truck 10 while wrapping, at its
top end, the bottom of the truck 10. More specifically, the gas-suction array may
include a plurality of wind-boxes 410 arranged along the traveling direction of the
trucks of the truck 10. Adj acent ones of the plurality of wind-boxes 410 may have
adjacent upper ends arranged side by side to each other in the extending direction
of the gas-suction array. Each of the plurality of wind-boxes 410 gas-communicates
with the interior space of the corresponding truck 10 via gaps defined in the bottom
11 of the corresponding truck 10. Each of the plurality of wind-boxes 410 creates
a negative pressure in the interior space of the corresponding truck to suck downwardly
the gas in the interior space of the corresponding truck 10, thereby allowing the
raceway in the raw-material layer to be transferred to from the upper material layer
thereof to the lower material layer thereof. In this process, the exhaust-gas is collected
into the plurality of wind-boxes 410.
[0055] After the truck 10 is subjected to ignition from the ignition furnace 30, each truck
travels in a first direction and travels along the gas-suction array. In this connection,
the gas-suction array generates a suction force in the downward direction within the
internal space of the corresponding truck 10. This suction force enables air outside
the truck 10 to flow into the interior space of the corresponding truck 10 and then
to enable the gas inside the inner space to be drawn downwards, thereby moving the
raceway downwards. When the corresponding truck 10 passes through the sintering region,
the raceway reaches the bottom 11 of the truck 10, thereby to complete the sintering
of the raw-material layer. As the corresponding truck 10 moves toward an end point
of the convey path, the sintered ore has been cooled. The cooled sintered ore may
be discharged via a sintered ore discharger at the end point of the convey path.
[0056] The plurality of wind-boxes 410 are spaced apart from the bottom 11 of the truck
10 by a predetermined gap. This is to prevent the moving truck 10 from colliding with
the wind-boxes 410 while the plurality of wind-boxes 410 suction downwards the gas
in the internal space of the truck. Further, the ventilation resistance in the interior
space of the truck varies, based on the sintered states of the raw-material, at various
points of each region, as the corresponding truck passes through each region. For
this reason, the plurality of wind-boxes 410 are spaced apart from the bottoms 11
of the truck 10 by a predetermined gap, in order to effectively suck the gas from
the interior space of the truck 10. That is, the adjacent and contacting upper ends
of the plurality of wind-boxes 410 are spaced apart from the bottoms 11 of the truck
10 by a predetermined distance.
[0057] On the other hand, the gas-suction array may have therein a gas circulation region
and a gas discharging region which are separated from each other. Accordingly, the
plurality of wind-boxes 410 may be divided into wind-boxes 411 disposed in the gas
circulation region and wind-boxes 412 disposed in the gas discharging region.
[0058] The gas circulation region of the gas suction array may correspond to a portion of
the gas-suction array extending from a first point in the sintering region to a second
point in the sintering region. In this connection, the first point in the sintering
region may correspond to a point at which the raceway in the raw-material layer reaches
the bottom 11 of the truck 10, thus completing the sintering of the raw-material layer.
The second point in the sintering region may correspond to a point at which a ventilation
resistance value of the sintered raw-material layer begins to fall below a predetermined
value.
[0059] Thus, the gas discharging region of the gas suction array corresponds to a combination
of a portion of the gas-suction array that extends from the beginning of the convey
path to the first point in the sintering region as described above, and a portion
of the gas-suction array extending from the second point in the sintering region to
the end point of the convey path. That is, the discharging region may correspond to
the remainder of the gas-suction array except for the circulation region.
[0060] The first point and the second point in the sintering region as described above are
merely an example for illustrating the present disclosure. The present disclosure
is not limited thereto. The sintering region may be configured in various ways depending
on the process requirements. Further, the above-defined division between the gas circulation
region and the gas discharging region is merely an exemplary one of various configurations
for circulating the exhaust gas. The gas circulation zone and the gas exhaust zone
may be configured in a variety of ways, thus exhausting and circulating the exhaust
gas in various ways.
[0061] Before describing the gas-blocking structure 413, the gas ventilation pipe 420, the
exhaust-gas circulation mechanism, and the exhaust-gas discharging mechanism of the
exhaust gas processing apparatus 400 according to an embodiment of the present disclosure
will be illustrated first.
[0062] The processing apparatus includes a plurality of gas ventilation pipes, and the plurality
of gas ventilation pipes are arranged so as to be spaced apart from each other along
the extended direction of the gas-suction array. The plurality of gas ventilation
pipes may communicate with the bottom of the gas-suction array, that is, the bottoms
of the plurality of wind-boxes 410, respectively. The gas ventilation pipe 420 may
be divided into gas ventilation pipes 421 communicating with the wind-boxes 411 disposed
in the gas circulation region, and gas ventilation pipes 422 communicating with the
wind-boxes 412 disposed in the gas discharging region.
[0063] The exhaust-gas circulation mechanism has a first end portion communicating with
some of the gas ventilation pipes 420, for example, the gas ventilation pipes 421
communicating with the wind-boxes 411 disposed in the gas circulation region and a
second end portion facing a predetermined position within the plurality of regions.
Thus, the exhaust-gas circulation mechanism can circulate the exhaust-gas sucked from
the points where the ventilation resistance of the sintered raw-material layer is
greatest, toward predetermined points on the plurality of regions.
[0064] In this connection, the second end portion of the exhaust-gas circulation mechanism
may be opened between the first point of the sintering region and the end point of
the convey path. In one embodiment, the second end portion of the exhaust-gas circulation
mechanism may be opened toward points downstream of the above-mentioned first point
of the sintering region. This means that the second end portion of the exhaust-gas
circulation mechanism is opened toward the downstream points of the sintering region,
where relatively less oxygen is consumed. Obviously, the second end portion of the
exhaust-gas circulation mechanism may be opened towards various points on the plurality
of regions, in addition to the points described above. In the following, reference
will be made to a configuration of the exhaust-gas circulation mechanism that is configured
to circulate the exhaust gas suctioned from the points where the ventilation resistance
of the sintered raw-material layer is maximum, toward the downstream points of the
sintering region.
[0065] The exhaust-gas circulation mechanism may include a circulation pipe 430, a circulation
blower 451, and a gas discharging hood 460. One end of the circulation pipe 430 communicates
with the gas ventilation pipes 421 communicating with the wind-boxes 411 disposed
in the gas circulation region. The other end of the circulation pipe 430 may communicate
with the gas discharging hood 460. The circulation blower 451 is, for example, a blower
for exhaust-gas circulation. The circulation blower 451 is mounted at one point of
the circulation pipe 430 to allow flow of exhaust gas from one end of the circulation
pipe 430 to the other end thereof. Due to this flow, an exhaust-gas circulation flow
may be generated within the wind-boxes 411 disposed in the gas circulation region.
[0066] The gas discharging hood 460 may extend in the direction of travel of the truck 10
and above the truck 10. The gas discharging hood 460 may extend between the end point
of the convey path and a certain point in the sintering region. The lower end of the
gas discharging hood 460 is open and the lower end thereof faces the truck 10. The
upper end of the gas discharging hood 460 may communicate with the other end of the
circulation pipe 430. The gas discharging hood 460 receives the exhaust gas from the
circulation pipe 430 and supplies the gas to the truck 10. Thereby, the exhaust gas
may be circulated.
[0067] Among the gas ventilation pipes 420, the gas ventilation pipes 422, which is not
connected to the exhaust-gas circulation mechanism, may communicate with the exhaust-gas
discharging mechanism. The exhaust-gas collected into the wind-boxes 412 disposed
in the gas discharging region may be discharged to the atmosphere through the exhaust-gas
discharging mechanism.
[0068] The exhaust-gas discharging mechanism has a first end portion and a second end portion.
The first end portion of the gas ventilation pipe 420 communicates with the second
gas ventilation pipe group 422 communicating with the wind boxes 412. The second end
portion may communicate with the atmospheric space. The exhaust-gas discharging mechanism
may exhaust the exhaust-gas collected into the wind-boxes 412 disposed in the gas
discharging region toward the atmospheric space. The exhaust-gas discharging mechanism
may include an elongate discharging chamber 440, a contaminant collector 470, a main
blower 452, and a gas discharging module 480.
[0069] The elongate discharging chamber 440 may be hollow. One end of the elongate discharging
chamber 440 may be connected to the gas ventilation pipes 422 which communicate with
the wind boxes 412 disposed in the gas discharging region. The other end of the elongate
discharging chamber 440 may be connected to the gas discharging module 480. The main
blower 452 is, for example, a blower for discharging the exhaust-gas and is mounted
at a predetermined position of the discharging chamber 440. The main blower 452 may
create flow of exhaust gas from one end of the discharging chamber 440 to the other
end thereof. Via this flow, exhaust-gas flow may be generated in the wind-boxes 412
disposed in the gas discharging region. The exhaust gas may contain contaminants such
as dust, nitrogen oxides and sulfur oxides. In order to filter these contaminants,
there is the contaminant collector 470 upstream of the main blower 452 in the exhaust-gas
flow direction. The contaminant collector 470 may be mounted at a predetermined position
of the discharging chamber 440.
[0070] A crushing unit (not shown) may be provided downstream of the sintering region. The
sintered ore discharged from the truck 10 is crushed into a predetermined size by
the crushing unit and, then the crushed ores are screened at a screen (not shown).
The screened sintered ores may be fed to other processes, such as a blast furnace
process, may be used as the upper-sintered ore, or may be re-used as the raw-material,
based on the particle sizes thereof.
[0071] Meanwhile, the main blower 452 and the circulation blower 451 have different suction-positions
and suction-areas. That is, the main blower 452 and the circulation blower 451 are
different in terms of the positions and numbers of wind-boxes that they must act on.
In addition, a ventilation level of the raw-material layer within the truck 10 moving
on and along the wind-boxes 412 connected to the main blower 452, and a ventilation
level of the raw-material layer within the trucks of the array 10 moving on and along
the wind-boxes 411 connected to the circulation blower 451 are also different. Due
to these differences, the main blower 452 and the circulation blower 451 have different
operating pressures.
[0072] Thus, the negative pressure applied by the main blower 452 to the wind-boxes 412
disposed in the gas discharging region, and the negative pressure applied by the circulation
blower 451 to the wind-boxes 411 disposed in the gas circulation region are different
from each other. An amount of exhaust gas sucked by the main blower 452 and an amount
of exhaust gas sucked by the circulation blower 451 are also different. For example,
the magnitude of the negative pressure applied by the circulation blower 451 to the
wind-boxes 411 disposed in the gas circulation region may be greater than the magnitude
of the negative pressure applied by the main blower 452 to the wind-boxes 412 disposed
in the gas discharging region. Of course, the opposite may also be true. That is,
the magnitude of the negative pressure in the gas discharging region may be greater.
[0073] In this case, the exhaust gas in the low negative pressure region may flow backward
toward the high negative pressure region. That is, at the boundary between the gas
circulation region and the gas discharging region having different negative pressures,
interference between the exhaust-gas flows may occur, resulting in the back-flow of
the exhaust gas to the region with a high negative pressure. The back-flowed exhaust-gas
may flow into the high negative pressure region through the gaps between the bottoms
11 of the truck 10 and the gas-suction array.
[0074] In this way, due to the difference in at least one of the operating pressure and
suction force between the main blower 452 and the circulation blower 451, a portion
of the exhaust gas that has to be discharged to the gas discharging region may flow
back into the gas circulation region having a higher negative pressure at the boundary
between the gas discharging region and the gas circulation region of the gas-suction
array. As a result, the exhaust-gas suction amount by the main blower 452 decreases.
This phenomenon is called flow-interference between the main blower 452 and the circulation
blower 451.
[0075] According to embodiments of the present disclosure, in order to suppress flow-interference
between the main blower 452 and the circulation blower 451 at the boundary between
the gas discharging region and the gas circulation region of the gas-suction array,
the gas-blocking structure 413 may be formed at the boundary to seal the gap between
the truck 10 and the gas-suction array.
[0076] Referring to FIG. 2, the gas-blocking structure 413 extends in a direction crossing
the traveling direction of the truck 10. The gas-blocking structure 413 may be formed
in a block shape, for example. The gas-blocking structure 413 may be disposed on adjacent
upper ends of some of the plurality of wind-boxes adjacent to the boundary while the
adjacent wind-boxes define the boundary between the exhaust-gas circulation region
and the exhaust-gas discharging region.
[0077] In this connection, the gap between the top of the gas-blocking structure 413 and
the bottom of the truck 10 may be greater than 0 but less than or equal to 100 mm
within a tolerance range. Here, the tolerance range may refer to a tolerance due to
a mechanical or electronic error of measuring means. Alternatively, the tolerance
range may refer to a minimum clearance that may prevent structural collision between
the truck 10 and the gas-blocking structure 413 due to structural deformations of
the bottom portion 11 of the truck 10 and the gas-blocking structure 413.
[0078] The gas-blocking structure 413 may narrow the gap between the bottom 11 of the truck
10 and the upper end of the wind-box at the boundary between the gas discharging region
and the gas circulation region. That is, the gas-blocking structure 413 may achieve
a substantially gas-blocking effect through the gap. Therefore, the backflow of gas
from the low negative pressure region to the high negative pressure region may be
suppressed. At other locations without the gas-blocking structure 413, the exhaust-gas
may flow freely through the spacing between the bottom 11 of the truck 10 and the
top of the wind-boxes. Thus, in each of the gas discharging region and the gas circulation
region, the suction of the exhaust gas may be stably achieved.
[0079] The gas-blocking structure 413 according to the embodiment of the present disclosure
may include various modifications as described below.
[0080] Referring to FIG. 3, a gas-blocking structure 413A according to a first modified
embodiment of the present disclosure may include a gas-blocking body 413' extending
in a direction crossing the traveling direction of the truck 10, and a flap 414 in
a form of a wing or plate extending from the gas-blocking body 413' in the traveling
direction of the truck 10. In this connection, the flap 414 may extend horizontally
from the upper end of the gas-blocking body 413' .
[0081] The flap 414 defines a gas flow blocking face above the wind-box where the flap 414
is located, such that it is possible to directly prevent the back-flow of the exhaust
gas from the lower negative pressure region, for example, the gas discharging region,
to the higher negative pressure region, for example, the gas circulation region. That
is, the flap 414 has significant significance in terms of hydrodynamics. This will
be described below in conjunction with numerical analysis of exhaust-gas flows within
the gas-suction array according to the embodiment of the present disclosure and a
gas-suction array according to a comparison example.
[0082] Also, The flap 414 may act to receive and support the raw material that falls down
through openings defined in the bottom 11 of the truck 10, thereby to further narrow
the gap between the truck 10 and the gas-suction array. In this way, more effective
gas flow blocking may be realized at the boundary between the gas discharging region
and the gas circulation region.
[0083] Referring to FIG. 5, a gas-blocking structure 413C according to a third modified
embodiment of the present disclosure may differ from the gas-blocking structure 413A
of the first modification as described above in terms of a height of the flap 414.
That is, the gas-blocking structure 413C according to the third modified embodiment
of the present disclosure may include a gas-blocking body 413' extending in a direction
crossing the traveling direction of the truck 10, and a flap 414 in a form of a wing
or plate extending from a lower portion of the gas-blocking body 413' in the traveling
direction of the truck 10.
[0084] In this way, in various modifications of the present disclosure, the flap 414 may
extend from the top or bottom portion of the gas-blocking body 413', or may extend
from a middle portion between the top and bottom portion of the gas-blocking body
413'. That is, the flap 414 may extend from various heights of the gas-blocking body
413'.
[0085] Referring to FIG. 3 and FIG. 5, the flap 414 may be located in a wind-box in at least
one of the gas circulation region and the gas discharging region. In this connection,
the flap may be located in the wind box of the lower negative pressure region among
the gas circulation region and gas discharging region. Further, in the gas-blocking
structure 413D of a fourth modification as described later and a gas-blocking structure
413E of a fifth modification as described later, a flap 414 may located in the wind
box of the region having the lower negative pressure among the gas circulation region
and the gas discharging region. In this connection, the first, third, fourth, and
fifth modifications of the present disclosure illustrate the flap 414 located in the
wind-box of the gas discharging region as the lower negative pressure region.
[0086] To the contrary, Referring to FIG. 4, a gas-blocking structure 413B according to
a second modification embodiment of the present disclosure may include a pair of flaps
414 respectively located in both a wind box of the gas circulation region and a wind
box of the gas discharging region. In other words, the gas-blocking structure 413B
according to the second modified embodiment of the present disclosure may include
a gas-blocking body 413' extending in a direction crossing the traveling direction
of the truck 10, a pair of flaps 414 in a form of a wing or plate and projecting from
the gas-blocking body 413' in the traveling direction of the truck 10 and being disposed
in the gas circulation region and the gas discharging region respectively.
[0087] Obviously, besides the modifications as described above, embodiments of the present
disclosure may further include various modifications including a flap 414 located
only in a wind box of the higher negative pressure region among the gas circulation
region and the gas discharging region. That is, the flap 414 according to the modifications
of the present disclosure may be located in a wind box of at least one of the gas
circulation region and the gas discharging region.
[0088] According to the modifications of the present disclosure, when the width of the top
of the wind-box facing the flap 414 is set to 1, the extension length of the flap
may be greater than 0 and less than or equal to 2/3. If the extension length of the
flap 414 exceeds 2/3 with respect to the width 1 of the top of the wind-box facing
the flap 414, the effect of preventing the back-flow of the exhaust gas becomes large,
but the exhaust-gas flow into the wind box facing the flap may be poor. For this reason,
the extension length of the flap 414 is equal to or less than 2/3 with respect to
the width 1 of the top of the wind-box facing the flap 414.
[0089] Referring to FIG. 6, a gas-blocking structure 413D according to the fourth modified
embodiment of the present disclosure may further include at least one rib 415 protruding
upwards from a top face of the flap 414. That is, the gas-blocking structure 413D
according to the fourth modified embodiment of the present disclosure may include
a gas-blocking body 413' extending in a direction crossing the traveling direction
of the truck 10, a flap 414 extending from the gas-blocking body 413' in the traveling
direction of the truck 10, and at least one rib 415 protruding upwards from a top
face of the flap 414.
[0090] In this connection, in FIG. 6, the flap 414 is shown which is disposed only in the
wind box of the gas discharging region and extends from the lower portion of the gas-blocking
body 413'. The present disclosure is not limited thereto. The flap 414 according to
the fourth modification of the present disclosure may be located only in the wind
box of the gas circulation region, or may be located in each of the wind box of the
gas discharging region and the wind box of the gas circulation region. In addition,
the flap 414 as described above may extend from portions with different heights, including
the upper and lower portions of the gas-blocking body 413 '.
[0091] The ribs 415 may be plural and may extend in the direction of travel of the truck
or in a direction crossing both the vertical direction and the direction of travel
of the truck. In this connection, some of the plurality of ribs 415 extend in the
traveling direction of the truck, while the remainder thereof extend in a direction
crossing both the vertical direction and the traveling direction of the truck, whereby
a grid structure may be achieved. By using this grid structure, the raw material falling
down onto the top surface of the flap 414 may be accommodated in the grid structure,
thereby suppressing or preventing the back-flow of the exhaust gas.
[0092] In addition, the above-mentioned rib 415 imposes flow resistance toward the exhaust
gas flowing on the top surface of the flap 414, and may suppress the exhaust gas from
flowing from the low negative pressure region to the high negative pressure region.
[0093] Referring to FIG. 7, a gas-blocking structure 414E according to the fifth modification
of the present disclosure may further include a tip portion 416 projecting downwardly
in a tilted manner from a distal end of the flap 414. That is, the gas-blocking structure
414E may include a gas-blocking body 413' extending in a direction crossing the traveling
direction of the truck 10, a flap 414 extending from the gas-blocking body 413' in
the traveling direction of the truck 10, and a tip portion 416 formed to project downwardly
in a tilted manner from a distal end of the flap 414 in a direction from the body
413' to an end of the flap 414.
[0094] Due to the tip portion 461, a larger gas flow blocking area in the wind-box facing
the flap 414 may be ensured reliably while it is possible to prevent collision between
the gas-blocking structure and the bottom 11 of the truck. For example, when the cross-sectional
area of the upper end of the wind-box facing the flap 414 is set to 1, a total extension
length of the flap 414 and the tip portion 416 in the direction of travel of the truck
may be greater than 0 and less than or equal to 2/3.
[0095] The features of the gas-blocking structures according to the above modifications
may be substituted each other or combined with each other to form various configurations
of the gas-blocking structures.
[0096] An exhaust gas processing apparatus for a raw-material processing equipment according
to another embodiment (second embodiment) of the present disclosure may be varied
as follows: the exhaust gas processing apparatus may include a plurality of wind-boxes
arranged along a movement direction of a truck and disposed below the truck, wherein
the truck is disposed to move along a plurality of regions while receiving therein
a raw-material, wherein the plurality of wind-boxes has an exhaust-gas circulation
region and an exhaust-gas discharging region which are separated from each other,
wherein upper ends of some of the plurality of wind-boxes protrude more upwardly than
upper ends of the remainder of the plurality of wind-boxes, wherein some of the plurality
of wind-boxes are adjacent to the boundary between the exhaust-gas circulation region
and exhaust-gas discharging region.
[0097] In one embodiment, some of the plurality of wind-boxes include first and second wind-boxes,
and the first and second wind-boxes define the boundary therebetween, and are disposed
in the exhaust-gas circulation region and exhaust-gas discharging region respectively,
wherein a spacing between the upper ends of the first and second wind-boxes and a
bottom face of the truck may be in a range of 0 exclusive to 100 inclusive mm in an
error range.
[0098] In this case, at the boundary between the gas discharging region and the gas circulation
region, there is disposed a gas-blocking structure at and between the upper ends of
the first wind-box and the second wind-box, in order to reduce the gap between the
bottom of the truck and the wind-boxes, more specifically, the gap between the bottom
of the truck and the upper ends of the first wind-box and the second wind-box. In
this connection, the configuration of the gas-blocking structure may be the same as
or similar to that of the gas-blocking structure according to the above-described
embodiment of the present disclosure. The remaining components of the exhaust gas
processing apparatus in this embodiment may be similar or identical to those of the
above-described embodiment of the present disclosure.
[0099] The gas-blocking structure according to the second embodiment of the present disclosure
may include various modifications. In this connection, configurations and operations
of the gas-blocking structure in accordance with modifications of the second embodiment
of the present disclosure may be identical or similar to those of the gas-blocking
structure according to the above-described modifications of the first embodiment of
the present disclosure.
[0100] FIG. 8 is a schematic diagram showing exhaust-gas flow for a gas-suction array according
to a comparison example. In this connection, the gas-suction array according to the
comparison example does not have a gas-blocking structure, and, thus, a gap between
the gas-suction array and the truck is, for example, more than 100 mm, as in the conventional
approach.
[0101] Referring to FIG. 8, in the comparison example, the gas-blocking structure is absent,
so that exhaust gas may flow back through the boundary between the gas discharging
region and the gas circulation region. Further, the exhaust-gas passing through the
raw-material layer may be concentrated on the gas circulation region, which is a high
negative pressure region. Thus, when such flow-interference occurs, the exhaust-gas
suction amount by the main blower communicating with the gas discharging region is
reduced, and, thus, the process efficiency may be lowered.
[0102] For example, as for a conventional sintering machine, there is a sufficient clearance
between the wind-box and the truck to allow the exhaust-gas to flow therethrough,
as shown in FIG. 8. When the sintering exhaust-gas circulation approach is applied
to the sintering machine with this configuration, and the firing area of the sintering
machine is increased, exhaust-gas control cannot be achieved reliably with a single
blower, and therefore, additional blowers must be installed. When a plurality of blowers
are operated, the exhaust gas may flow backward through the above-defined gap, and
the exhaust gas control efficiency may be lowered. In a sintering machine operating
the plurality of blowers, there should be no exhaust-gas transfer between wind-boxes
connected to different blowers, so that exhaust-gas control is performed effectively.
[0103] In the embodiments and modifications thereof of the present disclosure, a sintering
machine using two or more blowers can efficiently control the exhaust gas using the
gas-blocking structure. In order to illustrate the effect of the gas-blocking structure
according to the embodiments of the present disclosure, the exhaust-gas flow in the
gas-suction array for the comparison example and the embodiments of the present disclosure
will be numerically analyzed and the results thereof will be set forth.
[0104] FIG. 9 is a graph illustrating numerical analysis of the exhaust-gas flow in the
gas-suction array according to the embodiments of the present disclosure and the comparison
example. (a) of FIG. 9 shows a numerical analysis result of the exhaust-gas flow inside
the gas-suction array at the boundary between the gas discharging region and the gas
circulation region, according to the comparison example. (b) of FIG. 9 shows a numerical
analysis result of the exhaust-gas flow inside the gas-suction array at the boundary
between the gas discharging region and the gas circulation region, according to one
embodiment of the present disclosure. (c) of FIG. 9 shows a numerical analysis result
of the exhaust-gas flow inside the gas-suction array at the boundary between the gas
discharging region and the gas circulation region when using a gas-blocking structure
including a gas-blocking body and one flap, according to the first modification of
the present disclosure.
[0105] That is, (a) to (c) of FIG. 9 show results of flow analysis of the exhaust-gas flow
based on whether the gas-blocking body is present or not and whether the flap is present
or not. In this connection, a pressure difference between the main blower and the
circulation blower is set to 200 mmAq, and the circulation blower has a higher negative
pressure. In comparison between (a) and (b) of FIG. 9, as for the comparison example,
it may be confirmed that the exhaust gas from the gas discharging region flow-backs
forcedly into the gas circulation region, while as for the embodiment of the present
disclosure, it may be seen that this exhaust-gas flow-back is considerably reduced.
[0106] In this connection, the exhaust gas back-flow to the gas circulation region is considerably
reduced, but a portion of the exhaust-gas on the gas-blocking structure is still biased
toward the gas circulation region. In this connection, this exhaust-gas flow bias
may start from inside the truck. This is because the raw-material layer in the truck
has voids through which exhaust-gas in the raw-material layer may be easily biased
toward the gas circulation region.
[0107] Meanwhile, since the truck keeps running, the gas-blocking structure must be spaced
by a certain distance from the bottom of the truck. From inside the raw-material layer,
the biased exhaust-gas may flow along the top face of the gas-blocking structure into
the gas circulation region. In the modification of the present disclosure, to inhibit
or prevent the bias, the gas-blocking structure has the flap. The flap extends in
the direction of travel of the truck. Using this flap structure, the exhaust-gas flow
along and on the gas-blocking structure is not biased, but is substantially equally
divided into the gas discharging and circulation regions.
[0108] In comparison between (b) and (c) of FIG. 9, it may be seen that the gas-blocking
structure with the gas-blocking body and flap suppresses the exhaust-gas backflow
more effectively than the gas-blocking structure with only the gas-blocking body.
That is, the gas-blocking structure according to the modification of the present disclosure
may further include the flap to more effectively suppress the back-flow of the exhaust
gas. In this way, the inventors confirmed that the embodiment of the present disclosure
and its modification effectively suppress the back-flow of the exhaust-gas. On the
other hand, in order to see whether at least one of the gas-blocking body of the present
embodiment of the present disclosure and the flap of the modification thereof inhibits
the exhaust-gas flow-back, changes in exhaust-gas quantity at the gas-blocking body
and flap were measured.
[0109] FIG. 10 shows photographs of results of a reduced modeling experiment on the exhaust-gas
flow inside the gas-suction array, according to the comparison example, the embodiment
of the present disclosure, and its modifications, (a) of FIG. 10 shows a photograph
of a result of the reduced modeling experiment according to the comparison example.
(b) of FIG. 10 shows a photograph of a result of the reduced modeling experiment according
to the embodiment of the present disclosure. (c) of FIG. 10 shows a photograph of
a result of the reduced modeling experiment for a gas-blocking structure with a gas-blocking
body and a single flap, according to the first modification of the present disclosure.
[0110] In this experiment, when a cross-sectional area of an upper end of a wind-box is
set to 1, the extension length of the flap is set to 2/3. For the reduced modeling
experiment, a geometrically reduced model modelling an internal structure of each
gas-suction array corresponding to each of the comparison example, the embodiment
of the present disclosure and the modification thereof is prepared. Each experiment
was conducted for each reduced model using sintering conditions of the sintering machine.
[0111] The results of the reduced modeling experiment are shown in FIG. 11. FIG. 11 shows
a table indicating results of the reduced modeling experiment for exhaust-gas flow
in the gas-suction array according to the comparison example, the embodiment of the
present disclosure, and the modification thereof. In this connection, in FIG. 11,
the comparative example corresponds to the result of the reduced modeling experiment
in according to the comparative example of the present disclosure, the embodiment
1 corresponds to the result of the reduced modeling experiment according to the embodiment
of the present disclosure, while the embodiment 2 corresponds to the result of the
reduced modeling experiment for the blocking structure including the gas-blocking
body and the single flap, in accordance with the first modification of the present
disclosure.
[0112] Referring to these results, it may be seen that as for the embodiment 1 having the
gas-blocking body, the exhaust-gas flow rate is maintained reliably, as compared to
the comparative example. It may be seen that as for the embodiment 2 further including
the flap, the exhaust gas flow rate to the gas circulation region increases by 12%,
and a total flow rate increases by 11%, as compared to the comparative example. In
other words, the gas-blocking structure including only the gas-blocking body can maintain
the flow rate of the exhaust gas while suppressing flow-interference. The gas-blocking
structure, which further includes the flap, can simultaneously suppress the flow-interference
and increase the exhaust-gas flow rate.
[0113] The reason why the presence of the flap allows both the total exhaust-gas flow rate
and the exhaust-gas flow rate to the gas circulation region to increase is as follows.
As the flow-interference between the gas discharging region and the gas circulation
region is effectively suppressed or prevented by the flap, exhaust gas may be sufficiently
sucked from the raw material layer in the gas circulation region, which has relatively
high ventilation resistance.
[0114] Specifically, the negative pressure in the gas circulation region is not interfered
by the negative pressure in the gas discharging region. Thus, the negative pressure
in the gas circulation region acts on all or most of the raw-material layer in the
gas circulation region with the higher ventilation resistance. This allows the exhaust
gas flow rate in the gas circulation region to increase and, at the same time, allows
the exhaust gas to be sucked smoothly in the gas discharging region. This may increase
the overall exhaust-gas flow rate.
[0115] Hereinafter, a method of processing the exhaust gas using the exhaust gas processing
apparatus according to the embodiment of the present disclosure is described. The
exhaust gas processing method may include: loading a raw-material into a truck and
thermally-processing the raw-material in the truck while moving the truck along a
plurality of regions; suctioning downwardly an interior of the truck using a gas-suction
array; and suppressing gas flowing from a lower negative pressure region among an
exhaust-gas circulation region and an exhaust-gas discharging region into a space
between the gas-suction array and the truck.
[0116] In this connection, suppressing the exhaust-gas from flowing from the lower negative
pressure region into the space may includes: using a gas-blocking structure disposed
at a boundary between the exhaust-gas circulation region and exhaust-gas discharging
region.
[0117] First, the raw material is supplied to the raw-material hopper. In this connection,
the raw material is prepared by mixing and humidifying fine iron ore, limestone, fine
coke, and anthracite, and granulating them into several millimeters. The prepared
raw material is loaded into the raw-material hopper. In this connection, sintered
ores having a predetermined particle size is selected as the upper-sintered ores,
and the selected upper-sintered ores are loaded in the upper-sintered ore hopper.
[0118] Afterwards, the raw-material is loaded on the truck. The raw-material is thermally
treated while moving the truck along the plurality of regions.
[0119] Specifically, this heat treatment process includes: running the truck in the array
direction of a plurality of regions; loading the raw material into the truck using
the raw-material hopper; igniting the raw material with the ignition furnace to create
a raceway in the raw material inside the truck, and sintering the raw material while
moving the raceway from the upper end to the lower portion in the truck's interior
space.
[0120] More specifically, when the raw-material and upper-sintered ore are fed to the corresponding
hoppers respectively, the truck travels along the convey path in the array direction
of a plurality of regions. Then, in the loading region among the plurality of regions,
the upper-sintered ore is put on the bottom of the truck, and then the raw-material
is put on a top face of the upper-sintered ore, thereby to form a raw-material layer.
[0121] When the raw-material layer is formed, the raw-material layer is sequentially moved
along the ignition and sintering regions. In the ignition region, the raw-material
layer is ignited to form a raceway therein. Then, in the sintering region, the raw-material
layer is thermally treated at a high temperature of about 1300° C to 1400° C while
moving the raceway from the upper material layer to the lower material layer in the
raw-material layer, thereby to form a sintered ore.
[0122] At the same time as the above heat treatment process, the gas-suction array is used
to suck the gas inside the truck and to circulate some of the exhaust gas through
the truck and to exhaust the remaining gas. The gas-suction array is disposed below
the bottom of the truck and extends along the direction of the trucks. The gas-suction
array is divided into the gas circulation region and the gas discharging region. The
gas-suction array may be the gas-suction array as described above in the exhaust gas
processing apparatus according to the embodiments of the present disclosure. Via this
gas suction, the raceway may move from the upper end to the lower portion in the raw-material
layer, so that the raw-material is entirely sintered.
[0123] Together with suctioning the interior of the truck, the back-flow suppressing operation
may occur. The back-flow suppressing operation may include suppressing gas flowing
from a lower negative pressure region among the exhaust-gas circulation region and
an exhaust-gas discharging region, through the spacing between the gas-suction array
and the truck, to a higher negative pressure region among the exhaust-gas circulation
region and an exhaust-gas discharging region. In this connection, suppressing the
gas from flowing from the lower negative pressure region to the higher negative pressure
region may include using the above-define gas-blocking structure disposed at the boundary
between the exhaust-gas circulation region and exhaust-gas discharging region.
[0124] As described above, in the operation of suppressing the back-flow of the exhaust
gas by using the gas-blocking structure, at least one rib protruding upward from the
flap of the gas-blocking structure may be used to more effectively suppress the flow
of the exhaust gas flowing on an upper surface of the flap.
[0125] On the other hand, the use of the gas-blocking structure according to the embodiment,
and the use of flap and rib according to the modification thereof, to suppress or
prevent the back-flow of the exhaust gas has been described above several times. Therefore,
in order to avoid duplication of the description, the description thereof will be
omitted.
[0126] The finished sintered ores are discharged to the crushing unit at the end of the
convey path. The discharged sintered ores are crushed to a predetermined particle
size by the crushing unit. The crushed ores are screened by a screener. Depending
on the particle size, the screened ores may be fed to a blast furnace process, which
is a subsequent process, or alternatively, may be used as the upper-sintered ore,
or alternatively, may be considered as returned ores for reuse as the raw-material.
[0127] In accordance with the embodiments of the present disclosure, it is possible to decrease
the spacing between the gas-suction array and the truck at the boundary using the
gas-blocking structure disposed at the boundary between the exhaust-gas circulation
region and exhaust-gas discharging region. Thus, during producing the sintered ore
and circulating the exhaust gas, it is possible to suppress or prevent the gas flowing
backward due to the negative pressure difference between the discharge region and
the circulation region at the boundary between the discharge region and the circulation
region. Thus, the flow rate of the exhaust gas may be stably secured during the operation.
[0128] In accordance with the modifications of the present disclosure, the gas-blocking
structure has a flap or a combination of the flap and ribs, such that the total flow
rate of the exhaust gas and the flow rate of the exhaust gas to be circulated may
both be increased, whereby the efficiency of the operation can be further improved,
and high-quality sintered ores can be obtained.
[0129] The above embodiments of the present disclosure is merely for the illustration of
the present disclosure and is not for the limitation of the present disclosure. The
features presented in the above embodiments of the present disclosure may be combined
with or substituted with one another to form various modifications. It should be noted
that these modifications may be regarded as falling into the scope of the present
disclosure. The present disclosure will be embodied in various forms within the scope
of the claims and their equivalents. Those skilled in the art will appreciate that
various embodiments are possible within the scope or spirit of the present disclosure.
1. An exhaust gas processing apparatus including:
a gas-suction array extending in a traveling direction of a truck and disposed below
the truck which is disposed to move along a plurality of regions while processing
a raw-material, wherein the gas-suction array has an exhaust-gas circulation region
and an exhaust-gas discharging region which are separated from each other; and
a gas-blocking structure disposed at a boundary between the exhaust-gas circulation
region and exhaust-gas discharging region so as to seal the spacing between the gas-suction
array and the truck at the boundary.
2. The exhaust gas processing apparatus of claim 1, wherein the gas-suction array includes
a plurality of wind-boxes arranged along the traveling direction of the truck,
wherein the plurality of wind-boxes have respectively upper ends arranged side by
side along the extension of the gas-suction array, wherein the upper ends are coupled
to each other,
the gas-blocking structure is disposed on adjacent upper ends of some of the plurality
of wind-boxes adjacent to the boundary between the exhaust-gas circulation region
and the exhaust-gas discharging region, while the adjacent wind-boxes define the boundary
therebetween.
3. The exhaust gas processing apparatus of claim 1, wherein a spacing between a top face
of the gas-blocking structure and a bottom face of the truck at the boundary is greater
than 0 and less than or equal to 100 mm within a tolerance range.
4. An exhaust gas processing apparatus including:
a plurality of wind-boxes arranged along a traveling direction of a truck and disposed
below the truck, wherein the truck is disposed to move along a plurality of regions
while processing a raw-material, wherein the plurality of wind-boxes has an exhaust-gas
circulation region and an exhaust-gas discharging region which are separated from
each other,
wherein upper ends of some of the plurality of wind-boxes protrude more upwardly than
upper ends of the remainder of the plurality of wind-boxes, wherein some of the plurality
of wind-boxes are adjacent to a boundary between the exhaust-gas circulation region
and exhaust-gas discharging region.
5. The exhaust gas processing apparatus of claim 4, wherein some of the plurality of
wind-boxes include first and second wind-boxes, and the first and second wind-boxes
define the boundary therebetween, and are disposed in the exhaust-gas circulation
region and exhaust-gas discharging region respectively,
wherein a spacing between the upper ends of the first and second wind-boxes and a
bottom face of the truck may be greater than 0 and less than or equal to 100 mm.
6. The exhaust gas processing apparatus of claim 5, wherein the exhaust gas processing
apparatus further includes a gas-blocking structure disposed at and between the upper
ends of the first wind-box and the second wind-box so as to seal a gap between the
truck and some of the wind-boxes at the boundary.
7. The exhaust gas processing apparatus of one of claims 1 to 3, and 6, wherein the gas-blocking
structure includes a gas-blocking body extending in a direction crossing the traveling
direction of the truck; and a flap extending from the gas-blocking body in the traveling
direction of the truck.
8. The exhaust gas processing apparatus of claim 7, wherein the flap extends from at
least one of an upper end and a lower portion of the gas-blocking body or from a portion
between the upper end and the lower portion of the gas-blocking body.
9. The exhaust gas processing apparatus of claim 7, wherein the flap is disposed in at
least one of the exhaust-gas circulation region and exhaust-gas discharging region.
10. The exhaust gas processing apparatus of claim 7, wherein the flap is disposed in a
lower negative pressure region among the exhaust-gas circulation region and the exhaust-gas
discharging region.
11. The exhaust gas processing apparatus of claim 7, wherein when a cross-sectional area
of an upper end of a wind-box facing the flap is set to 1, an extension length of
the flap is greater than 0 and less than or equal to 2/3.
12. The exhaust gas processing apparatus of claim 7, wherein the gas-blocking structure
further includes at least one rib formed to protrude upwards from a top face of the
flap.
13. The exhaust gas processing apparatus of claim 12, wherein the rib extends in the traveling
direction of the truck; or the rib may extend in a direction crossing the traveling
direction of the truck.
14. The exhaust gas processing apparatus of claim 13, wherein the gas-blocking structure
includes a plurality of ribs, wherein some of the plurality of ribs extends in the
traveling direction of the truck, while the remainder thereof extends in a direction
crossing the traveling direction of the truck.
15. The exhaust gas processing apparatus of claim 7, wherein the gas-blocking structure
further includes a tip portion projecting downwardly in a tilted manner from a distal
end of the flap in a direction from the gas-blocking body of the gas-blocking structure
to an end of the flap.
16. The exhaust gas processing apparatus of claim 15, wherein when a cross-sectional area
of an upper end of a wind-box facing the flap is set to 1, a sum of extension lengths
of the flap and the tip portion in the traveling direction of the truck is greater
than 0 and less than or equal to 2/3.
17. An exhaust gas processing method including:
loading a raw-material into a truck and thermally-processing the raw-material in the
truck while moving the truck along a plurality of regions;
suctioning downwardly an interior of the truck using a gas-suction array, wherein
the gas-suction array extends in a traveling direction of the truck and disposed below
the truck, wherein the gas-suction array has an exhaust-gas circulation region and
an exhaust-gas discharging region which are separated from each other; and
suppressing exhaust-gas flowing from a lower negative pressure region among the exhaust-gas
circulation region and exhaust-gas discharging region into a space between the gas-suction
array and the truck.
18. The method of claim 17, wherein suppressing the exhaust-gas from flowing from the
lower negative pressure region into the space includes using a gas-blocking structure
disposed at a boundary between the exhaust-gas circulation region and exhaust-gas
discharging region.