[Title of Invention] BLAST FURNACE INSTALLATION
[Technical Field]
[OOOl]
The present invention relates to a blast furnace installation.
[Background Art]
[0002]
Blast furnace installations have been configured so as to be capable of
producing pig iron from iron ore by charging a starting material such as iron
ore, limestone, or coal from the top into the interior of the blast furnace body
and blowing hot air and pulverized coal (pulverized coal injection: PC1 coal) as
auxiliary fuel from a tuyere disposed at a lower portion on the side of the blast
furnace body.
[Citation List]
[Patent Literatures]
[0003]
[Patent Literature 11 Japanese Unexamined Patent Application Publication No.
H4-0935 12A
[Patent Literature 21 Japanese Unexamined Patent Application Publication No.
H10-060508A
[Patent Literature 31 Japanese Unexamined Patent Application Publication No.
HI1 -092809A
[Patent Literature 41 Japanese Unexamined Patent Application Publication No.
2007-2390 19A
[Summary of Invention]
[Technical Problem]
[0004]
If the PC1 coal blown into the interior of the blast furnace body as
auxiliary fuel generates unburned carbon, there is the possibility of the
unburned carbon obstructing the flow of combustion gas. Therefore, since high
combustion performance is required, expensive, high-grade anthracite coal,
bituminous coal, or the like is used, causing an increase in the production cost
of pig iron.
[0005]
Accordingly, an object of the present invention is to provide a blast
furnace installation that can reduce the production cost of pig iron.
[Solution to Problem]
To solve the above problem, the blast furnace installation pertaining to
the first invention is a blast furnace installation equipped with a blast furnace
body, a starting material charging means for charging starting material from a
top into an interior of the blast furnace body, a hot air blowing means for
blowing hot air into the blast furnace body through a tuyere, and a pulverized
coal supply means for supplying pulverized coal into the blast furnace body
through the tuyere, wherein the pulverized coal is obtained by means of dry
distillation of low-grade coal, and the pulverized coal supply means is equipped
with a pneumatic conveying means for pneumatically conveying the pulverized
coal to the tuyere by means of a carrier gas made of a mixture of air and an
inert gas; a carrier gas state detection means for detecting a state of the carrier
gas near the tuyere; and a control means for adjusting the mixing ratio between
the air and the inert gas in the carrier gas of the pneumatic conveying means on
the basis of information from the carrier gas state detection means.
[0007]
The blast furnace installation pertaining to the second invention is the
first invention wherein the carrier gas state detection means of the pulverized
coal supply means detects at least one state among the temperature, oxygen
concentration, carbon monoxide concentration and carbon dioxide
concentration of the carrier gas.
[OOOS]
The blast furnace installation pertaining to the third invention is the first
or second invention wherein the control means of the pulverized coal supply
means adjusts the mixing ratio between the air and the inert gas in the carrier
gas of the pneumatic conveying means such that the temperature of the carrier
gas is from 200°C to T°C (wherein T is the dry distillation temperature of the
low-grade coal).
[0009]
The blast furnace installation pertaining to the fourth invention is any
one of the first to third inventions wherein the pulverized coal has been drydistilled
at from 400°C to 600°C.
[OOl 01
The blast furnace installation pertaining to the fifth invention is any one
of the first to fourth inventions wherein the pulverized coal has a diameter of
not more than 100 pm.
[OOll]
I
I The blast furnace installation pertaining to the sixth invention is any one
I
I of the first to fifth inventions wherein the low-grade coal is sub-bituminous
coal or lignite.
[OO 121
The blast furnace installation pertaining to the seventh invention is any ~ one of the first to sixth inventions wherein the inert gas is at least one among
I nitrogen gas, off-gas discharged from the blast furnace body, and combustion
exhaust gas after the off-gas has been combusted with air.
[Advantageous Effects of Invention]
[00 1 31
By the blast furnace installation pertaining to the present invention, the
production cost of pig iron can be reduced due to the fact that inexpensive lowgrade
coal can be used as the blowing coal (PC1 coal) because pulverized coal
obtained by means of dry distillation of low-grade coal is pneumatically
conveyed to a tuyere by means of a carrier gas obtained by mixing air and inert
gas, and due to the fact that ignitability (burn-out capability) of the blowing
coal (PC1 coal) can be improved without providing a heater, heat exchanger or
the like for heating the carrier gas and pulverized coal. ~urthermore,w ith
improvement of ignitability (burn-out capability) of the blowing coal (PC1
coal), the supplied quantity of blowing coal (PC1 coal) may be reduced and the
production cost of pig iron can be further reduced. Conversely, with
improvement of ignitability (burn-out capability) of the blowing coal (PC1
coal), the supplied quantity of blowing coal (PC1 coal) may be increased, and
therefore the quantity of coal (coke) supplied as a starting material to the top of
the blast furnace body may be reduced and the production cost of pig iron can
be further reduced.
[Brief Description of Drawings]
[00 141
[FIG. 11 FIG. 1 is a schematic configuration diagram of essential parts of a first
embodiment of the blast furnace installation pertaining to the present invention.
[FIG. 21 FIG. 2 is a control system diagram of essential parts of the blast
furnace installation of FIG. 1.
[FIG. 31 FIG. 3 is a schematic configuration diagram of essential parts of a
second embodiment of the blast furnace installation pertaining to the present
invention.
[FIG. 41 FIG. 4 is a control system diagram of essential parts of the blast
furnace installation of FIG. 2.
[Description of Embodiments]
[00 151
Embodiments of the blast furnace installation pertaining to the present
invention will be described based on the drawings, but the present invention is
not limited only to the following embodiments described based on the drawings.
[00 1 61

A first embodiment of the blast furnace installation pertaining to the
present invention will be described based on FIGS. 1 and 2.
[00 171
As illustrated in FIG. 1, a starting material dispensing device 11 1 for
dispensing a starting material 1 such as iron ore, limestone or coal is connected
on the upstream side of the conveyance direction of a charging conveyor 11 2
which conveys the starting material 1. On the downstream side of the
conveyance direction of the charging conveyor 112, a throat hopper 11 3 of the
top of a blast furnace body 110 is connected. A hot air feeding device 114
which feeds hot air 101 (from 1000°C to 1300°C) is connected to a blow pipe
11 5 provided on a tuyere of the blast furnace body 11 0.
COO1 81
The distal side of an injection lance 116 is inserted and connected part .
way along the blow pipe 11 5. A blast opening of an air blower 1 17 which feeds
air 106 is connected to the proximal side of the injection lance 11 6. Between ,
the blast opening of the air blower 11 7 and the proximal side of the injection
lance 116, an inert gas supply source 11 9, which feeds an inert gas 102 such as
nitrogen gas or the like is connected via a flow rate adjustment valve 11 8.
[OO 1 91
Between the air blower 11 7 and flow rate adjustment valve 11 8 and the
injection lance 116, the bottom part of a supply tank 120 is connected, wherein .
pulverized coal 2, obtained by means of dry distillation of low-grade coal such
as lignite or sub-bituminous coal at temperature T (from 400°C to 600°C) and
then pulverizing (diameter not more than 100 pm), may enter the interior of the
supply tank 120. The'interior of the supply tank 120 can be held in an inert gas
atmosphere, and the pulverized coal 2 can be supplied by dropping from the
interior.
[0020]
Near the proximal side of the injection lance 116, that is, near the tuyere,
a temperature sensor 12 1, which is a carrier gas state detection means for
detecting the temperature inside the injection lance 116, is provided. As
D E k H I L E - 0 1 - 2 0 1 % 17 -4%
4
illustrated in FIG. 2, the temperature sensor 121 is electrically connected to the
input part of a control unit 122 which is a control means. The output part of
the control unit 122 is electrically connected to the air blower 117 and the flow
rate adjustment valve 11 8, and the control unit 122 can control the blast volume
of the air blower 11 7 and the openness of the flow rate adjustment valve 11 8 on
the basis of information from the temperature sensor 12 1 (details will be
described later).
[002 11
Furthermore, in this embodiment, a starting material charging means is
constituted by the starting material dispensing device 11 1, the charging
conveyor 11 2, the throat hopper 11 3 and the like; a hot air blowing means is
constituted by the hot air feeding device 114, the blow pipe 11 5 and the like; a
pneumatic conveying means is constituted by the blow pipe 11 5, the injection
lance 11 6, the air blower 11 7, the flow rate adjustment valve 11 8, the inert gas
supply source 11 9, the supply tank 120 and the like; and a pulverized coal
supply means is constituted by the pneumatic conveying means, the carrier gas
state detection means, the control means and the like. Furthermore, in FIG. 1,
110a is a taphole for drawing out melted pig iron (molten iron) 9.
[0022]
In the blast furnace installation 100 pertaining to this embodiment, the
starting material 1 is charged into the blast furnace body 11 0 by being
dispensed from the starting material dispensing device 11 1 and then being
supplied into the throat hopper 11 3 via the charging conveyor 112, while on the
other hand, hot air 101 is fed from the hot air feeding device 114 to the blow
pipe 115, and pulverized coal 2 is supplied by dropping from the supply tank
120.
[0023]
When the control unit 122 is operated, the control unit 122 operates the
air blower 117 so as to feed air 106 from the air blower 117, and opens the flow
rate adjustment valve 11 8 so as to feed inert gas 102 from the inert gas supply
source 119.
[0024]
As a result, the pulverized coal 2 is pneumatically conveyed to the
injection lance 11 6 by carrier gas 107 made of a mixture of air 106 and the
inert gas 102. At this time, because the pulverized coal 2 has been increased in
reactivity by being dry-distilled and because the carrier gas 107 contains
oxygen, some of the pulverized coal 2 reacts with oxygen and burns during
I pneumatic conveyance. For this reason, the carrier gas 107 and the pulverized
coal 2 are preheated (from 200°C to T°C) by self-heating.
[0025]
The pulverized coal 2 pneumatically conveyed into the injection lance
116 is supplied together with the carrier gas ,107 into the interior of the blow
pipe 11 5, and is supplied from the hot air feeding device 114 into the hot air
101, thereby being burned. At this time, because the carrier gas 107 and the
' pulverized coal 2 blown into the hot air 101 from the injection lance 116 have
been preheated (from 200°C to T°C), the ignitability and burn-out capability of
the pulverized coal 2 are improved.
[0026]
Here, if the temperature of the carrier gas 107 blown into the hot air 1.01
from the injection lance 116, that is, the temperature of the carrier gas 107 near
the tuyere, is less than 200°C, the control unit 122 controls the air blower 11 7
and the flow rate adjustment valve 11 8 so as to increase the burning capacity of
the pulverized coal 2 being pneumatically conveyed to the injection lance 116
on the basis of information from the temperature sensor 121, to increase the
. . blast volume of the air blower 117 and reduce the openness of the flow rate
adjustment valve 11 8 so as to increase the oxygen concentration in the carrier
gas 107 while holding the flow rate of the carrier gas 107 constant.
[0027]
On the other hand, if the temperature 0.f the carrier gas 107 blown into
the hot air 101 from the injection lance 116, that is, the temperature of the
carrier gas 107 near the tuyere, is greater than T°C, the control unit 122
controls the air blower 11 7 and the flow rate adjustment valve 11 8 so as to
decrease the burning capacity of the pulverized coal 2 being pneumatically
conveyed to the injection lance 11 6 on the basis of information from the
temperature sensor 12 1, to decrease the blast volume of the air blower 1 17 and
increase the openness of the flow rate adjustment valve 11 8 so as to decrease
the oxygen concentration in the carrier gas 107 while holding the flow rate of
the carrier gas 107 constant.
[0028]
In this manner, the pulverized coal 2 blown into the hot air 101 from the
injection lance 11 6 and burned in the interior of the blow pipe 11 5 becomes a
flame and forms a raceway from the tuyere to the interior of the blast furnace
body 110, and burns the coal and the like in the starting material 1 inside the
blast furnace body 110. As a result, the iron ore in the starting material 1 is .
reduced to result in pig iron (molten iron) 9, which is drawn out from the
taphole 1 10a.
[0029]
In short, in the blast furnace installation 100 pertaining to this
embodiment, pulverized coal 2 obtained by means of dry distillation of lowgrade
coal such as lignite, sub-bituminous coal or the like at temperature T
(from 400°C to 600°C) and then pulverizing (diameter not more than 100 pm)
is used as blowing coal (pulverized coal injection: PC1 coal), and a mixed gas
of air 106 and inert gas 102 is used as the carrier gas 107 that pneumatically
conveys the pulverized coal 2 to the injection lance 116.
[0030]
For this reason, in the blast furnace installation 100 pertaining to this
embodiment, inexpensive low-grade coal can be used as the blowing coal (PC1
coal), and ignitability (burn-out capability) of the blowing coal (PC1 coal) can
be improved without providing a heater, heat exchanger or the like for heating
the carrier gas 107 and pulverized coal 2.
[003 11
Therefore, by the blast furnace installation 100 pertaining to this
embodiment, the production cost of pig iron 9 can be reduced.
COO321
Furthermore, with improvement of ignitability (burn-out capability) of
the blowing coal (PC1 coal), the supplied quantity of blowing coal (PC1 coal)
may be reduced and the production cost of pig iron 9 can be further reduced.
Conversely, with improvement of ignitability (burn-out capability) of the
blowing coal (PC1 coal), the supplied quantity of blowing coal (PC1 coal) may
be increased, and therefore the quantity of coal (coke) supplied as a starting
material 1 to the top of the blast furnace body 110 may be reduced and the
production cost of pig iron 9 can be further reduced.
[0033]
Furthermore, the preheating temperature of the carrier gas 107 and the
pulverized coal 2 is preferably from 200°C to T (dry distillation temperature of
pulverized coal 2) "C. This is because if it is less than 200°C, there is risk that
it will be difficult to sufficiently improve the ignitibility (burn-out capability)
of the pulverized coal 2, and if it exceeds T (dry distillation temperature of
pulverized coal 2) "C, thermolysis products such as tar end up being produced
from the pulverized coal 2, and these thermolysis products adhere to the inner
wall surfaces of the injection lance 116 and the like, leading to the risk of
blockage of the injection la c e like.
O E L H I 2 2 -01 - 2 0 2 5 ' ' 8 ~ 4 ~ h - j .
''
[0034]

A second embodiment of the blast furnace installation pertaining to the
present invention will be described based on FIGS. 3 and 4. Note that the same
reference numerals as those used in the description of the embodiment above
are used for the portions that are the same as in the embodiment above, and
therefore, descriptions that are the same as in the embodiment above are
omitted.
[0035]
As illustrated in FIG. 3, the proximal side of a fractionation line 223 is
connected near the proximal end of the injection lance 11 6 between the
injection lance 116 and the supply tank 120. The distal side of the fractionation
line 223 is connected to one port of a three-way valve 224. The remaining two
ports of the three-way valve 224 are respectively connected to filter devices
2 2 5a~nd 225B.
[0036]
The outlet ports of the filter devices 225A and 225B are connected to the
suction port of a suction pump 226. The outlet port of the suction pump 226 is
connected via a return line 227 between the proximal side of the fractionation
line 223 and the proximal side of the injection lance 11 6. A CO sensor 22 1
which detects the carbon monoxide concentration in the carrier gas 107
fractionated from the fractionation line 223 is provided between the outlet ports
of the filter devices 225A and 225B and the suction port of the suction pump
226.
[0037]
As illustrated in FIG. 4, the CO sensor 221 is electrically connected to
the input part of the control unit 222 which is the control means. The output
part of the control unit 222 is electrically connected to the air blower 117 and
the flow rate adjustment valve 11 8, and the control unit 222 can control the
blast volume of the air blower 11 7 and the openness of the flow rate adjustment
valve 11 8 on the basis of information from the CO sensor 221 (details will be
.described later).
[003 81
Furthermore, in this embodiment, a carrier gas state detection means is
constituted by the CO sensor 22 1, the fractionation line 223, the three-way
valve 224, the filter devices 225A and 225B, the suction pump 226, the return
line 227 and the like; and a pulverized coal supply means is constituted by the
I carrier gas state detection means, the control means, the pneumatic conveying
means and the like.
[0039]
In the blast furnace installation 200 pertaining to this embodiment,
similar to the embodiment described above, the starting material 1 is charged
into the blast furnace body 110, while on the other hand, hot air 101 is fed from
the hot air feeding device 114 to the blow pipe 11 5, and pulverized coal 2 is
supplied by dropping from the supply tank 120.
[0040]
Then, the three-way valve 224 is opened and closed such that only one
of the filter devices 225A and 225B (for example, filter device 225A) connects
to the fractionation line 223 and the return line 227, and when the suction pump
226 is operated and the control unit 222 is operated, the control unit 222
operates the air blower 11 7 so as to feed air 106 from the air blower 11 7, and
also opens the flow rate adjustment valve 11 8 so as to feed inert gas 102 from
the inert gas supply source 119, similar to the embodiment described above.
[004 11
As a result, similar to the embodiment described above, the pulverized
coal 2 is pneumatically conveyed to the injection lance 116 by carrier gas 107
made of a mixture of air 106 and the inert gas 102, and is supplied together
with the carrier gas 107 to the interior of the blow pipe 11 5, and is supplied
from the hot air feeding device 114 into the hot air 10 1, thereby being burned.
[0042]
Here, the carrier gas 107 pneumatically carried to near the proximal side
of the injection lance 11 6 is partially fractionated in the fractionation line 223
by the suction pump 226 and passes through the three-way valve 224; and after
the pulverized coal 2 and the like are removed by the filter device 225A, the
carbon monoxide concentration of the carrier gas 107 is detected by the CO
sensor 221, and the carrier gas 107 is then returned from the return line 227 via
the suction pump 226 to near the proximal side of the injection lance 116.
[0043]
Then, the control unit 222 controls the blast volume of the air blower
11 7 and the openness of the flow rate adjustment valve 11 8 on the basis of
information from the CO sensor 221. Specifically, the carbon monoxide
I concentration in the carrier gas 107 is a value substantially determined by the
type of the pulverized coal 2 (coal type), the supply quantity of the pulverized
coal 2, the oxygen concentration in the carrier gas 107, and the temperature of
the carrier as 107+ -
IPO ELH HI 25-eA 0. I I7 '. 43.
[0044]
For this reason, the temperature of the carrier gas 107 can be determined
by detecting the carbon monoxide concentration in the carrier gas 107 since the
supply quantity and type of the pulverized coal 2 (coal type) are predetermined .
and the oxygen concentration in the carrier gas 107 can be calculated.
[0045]
More specifically, the control unit 222 calculates the temperature of the
carrier gas 107 on the basis of information from the CO sensor 221, that is, the
carbon monoxide concentration of sampled carrier gas 107, in other words, the
carbon monoxide concentration and the like in the carrier gas 107 near the
tuyere, and if that temperature is less than 200°C, the control unit.222 controls
the air blower 1 17 and the flow rate adjustment valve 1 18 so as to increase the
burning capacity of the pulverized coal 2 being pneumatically conveyed to the
injection lance 11 6, to increase the blast' volume of the air blower 11 7 and
reduce the openness of the flow rate adjustment valve 11 8 so as to increase the
oxygen concentration in the carrier gas 107 while holding the flow rate of the
carrier gas 107 constant.
[0046]
On the other hand, if the calculated temperature is greater than T°C, the
control unit 222 controls the air blower 11 7 and the flow rate adjustment valve
11 8 so as to decrease the burning capacity of the pulverized coal 2 being
pneumatically conveyed to the injection lance 116, to decrease the blast volume
of the air blower 117 and increase the openness of the flow rate adjustment
valve 118.~a0s to decrease the oxygen concentration in the carrier gas 107
while holding the flow rate of the carrier gas 107 constant.
[004.7]
As a result, similar to the embo'diment described above, the pulverized
coal 2 blown into the hot air 10 1 from the injection lance 1 16 and burned in the
interior of the blow pipe 11 5 becomes a flame and forms a raceway from the
tuyere to the interior of the blast furnace body 11 0, and burns the coal and the
like in the starting material 1 inside the blast furnace body 110, and the iron ore
in the starting material 1 is reduced to result in pig iron (molten iron) 9, which
can be drawn out from the taphole 11 0a.
[0048]
Furthermore, since the filter device 225A gradually becomes clogged
due to sampling of the carrier gas 107, sampling of the carrier gas 107 can be
continuously performed by opening and closing the three-way valve 224 so as
to connect only the filter device 225B to the fractionation line 223 and the
I P O DELHI 22-01-2015 17: 41
10
return line 227 and replacing the filter device 225A with a new one after a
prescribed time has elapsed.
[0049]
In short, in the blast furnace installation 100 pertaining to the
embodiment described above, the temperature of the carrier gas 107 is directly
detected by the temperature sensor 12 1 provided near the proximal side of the
injection lance 11 6, but in the blast furnace installation 200 pertaining to this
embodiment, the temperature of the carrier gas 107 is determined by
calculation by the control unit 222 by sampling the ~ a r r i e r ' ~1a0s7 near the
proximal side of the injection lance 116 by a sampling line and detecting its
carbon monoxide concentration by a CO sensor 221.
[0050]
For this reason, in the blast furnace installation 200 pertaining to this
embodiment, the temperature of the carrier gas 107 can be detected without
sticking the detector part of a sensor or the like into the line through which the
majority of the carrier gas 107 flows.
[005 11
Therefore, by the blast furnace installation 200 pertaining to this
embodiment, since the same effects as the previously described embodiment
can naturally be obtained and adhesion and the like of the pulverized coal 2 to
the detector part of the sensor can be prevented, more accurate control can be
performed, and blockage and the like near the proximal side of the injection
lance 11 6 can be prevented.
[0052]

Furthermore, in the second embodiment described above, the
temperature of the carrier gas 107 is determined by detecting the carbon
monoxide concentration in the carrier gas 107 by the CO sensor.22 1, but as
another embodiment, the temperature of the carrier gas 107 can also be
determined by employing, for example, a C02 sensor that detects the carbon
dioxide concentration or an O2 sensor that detects the oxygen concentration in
the carrier gas 107, instead of the CO sensor 22 1.
[0053]
In the first and second embodiments described above, the case where
inert gas 102 such as nitrogen gas is fed from the inert gas supply source 11 9
was described, but as another embodiment, for example, blast furnace off-gas
(approximately 200°C) discharged from the blast furnace body 110 or
combustion exhaust gas (approximately 100°C) of blast furnace off-gas, which
I P Q D E L H I 8 2 - 0 1 - 2 0 1 5 B7:dX
.- . d4has been generated after the blast furnace off-gas is combusted with air and has
been used as a heat source of the hot air 10 1, may be employed as the inert gas
102. That is, the blast furnace body 11 0 or the hot air feeding device 11 4 or the
like may also be used as the inert gas supply source.
[Industrial Applicability]
[0054]
The blast furnace installation pertaining to the present invention can be ~
used extremely advantageously in the iron-making industry because it can
reduce the production cost of pig iron.
[Reference Signs List]
[OO 5 51
1 Starting material
2 Pulverized coal
Molten iron
Blast furnace installation
Hot air
Inert gas
Air
Carrier gas
Blast furnace body.
Taphole
11 1 Starting material dispensing device
1 12 Charging conveyor
1 13 Throat hopper
1 14 Hot air feeding device
115 Blow pipe
11 6 Injection lance
11 7 Air blower
11 8 Flow rate adjustment valve
1 19 Inert gas supply source
120 Supply tank
12 1 Temperature sensor
122 Control unit
200 Blast furnace installation
221 CO sensor
222 Control unit
223 Fractionation line
224 Three-way valve
190 DE'LHI 22-81-2.QP5 17 141
12
'4)
225A, 225B Filter devices
226 Suction pump
227 Return line
[Document Name] Claims
[Claim 11
A blast furnace installation including:
a blast furnace body;
starting material charging means for charging starting material from a top into
an interior of the blast furnace body;
hot air blowing means for blowing hot air into the interior of the blast furnace
body through a tuyere; and
pulverized coal supply means for supplying pulverized coal into the interior of
the blast furnace body through the tuyere; wherein
the pulverized coal is obtained by means of dry distillation of low-grade
coal; and
the pulverized coal supply means includes:
pneumatic conveying means for pneumatically conveying the
pulverized coal to the tuyere by means of a carrier gas made of a
mixture of air and an inert gas;
carrier gas state detection means for detecting a state of the
carrier gas near the tuyere; and
control means for adjusting a mixing ratio between the air and the
inert gas in the carrier gas of the pneumatic conveying means
based on information from the carrier gas state detection means.
[Claim 21
The blast furnace installation according to claim '1, wherein
the carrier gas state detection means of the pulverized coal supply means
detects at least one state among temperature, oxygen concentration, carbon
monoxide concentration and carbon dioxide concentration of the carrier gas.
[Claim 31
The blast furnace installation according to claim 1, or 2, wherein
the control means of the pulverized coal supply means adjusts a mixing
ratio between the air and the inert gas in the carrier gas of the pneumatic
conveying means such that the temperature of the carrier gas is from 200°C to
T°C (wherein T is a dry distillation temperature of the low-grade coal).
[Claim 41
The blast furnace installation according to any one of claim 1 to 3,
wherein
the pulverized coal is dry-distilled at from 400°C to 600°C.
[Claim 51
The blast furnace installation according to any one of claim 1 to 4,
wherein
the pulverized coal has a diameter of not more than 100 pm.
[Claim 61
The blast furnace installation according to any one of claim 1 to 5,
wherein
the low-grade coal is sub-bituminous coal or lignite.
[Claim 71
The blast furnace installation according to any one of claim 1 to 6,
wherein
the inert gas is at least one among nitrogen gas, off-gas discharged from
the blast furnace body, and combustion exhaust gas after the off-gas has been
combusted with air.