TECHNICAL FIELD
The present invention relates to a blast furnace installation.
BACKGROUND ART
5 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
10 furnace body.
PRIOR ART DOCUMENTS
Patent Documents
Patent Document 1: Japanese Unexamined Patent Application Publication
15 NO. H04-0935 12A
Patent Document 2: Japanese Unexamined Patent Application Publication
NO. H10-060508A
Patent Document 3: Japanese Unexamined Patent Application Publication
NO, H 11 -092809A
20 Patent Document 4: Japanese Unexamined Patent Application Publication
NO. 2007-23 90 19A
SUMMARY OF THE INVENTION
Technical Problem
25 If the PCI coal blown into 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.
30 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 Problems
To solve the above problems, the blast furnace installation pertaining to the
35 first invention is 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
supply means is equipped with a moisture removal means for high-grade coal for
evaporating moisture in high-grade coal; a pulverization means for high-grade coal
5 for pulverizing the high-grade coal, from which moisture has been removed by the
moisture removal means for high-grade coal, to provide pulverized coal; a
moisture removal means for low-grade coal for evaporating moisture in low-grade
coal; a pyrolysis means for pyrolyzing the low-grade coal from which moisture has
been removed by the moisture removal means for low-grade coal; a cooling means
10 for cooling the low-grade coal that has been pyrolyzed by the pyrolysis means; a
pulverization means for low-grade coal for pulverizing the low-grade coal that has
been cooled by the cooling means, to provide pulverized coal; a supply tank of
which the interior is maintained in an inert gas atmosphere, and into the interior of
which are put the pulverized coal of high-grade coal and the pulverized coal of
15 low-grade coal obtained through pulverization by the pulverization means for
high-grade coal and the pulverization means for low-grade coal; a conveying
means for high-grade coal for conveying the pulverized coal of high-grade coal
obtained through pulverization by the pulverization means for high-grade coal into
the supply tank; a supply amount adjustment means for high-grade coal for
20 adjusting a supply amount C1 of the pulverized coal of high-grade coal to be
conveyed into the supply tank; a conveying means for low-grade coal for
pneumatically conveying the pulverized coal of low-grade coal obtained through
pulverization by the pulverization means for low-grade coal into the supply tank
by an inert gas; a supply amount adjustment means for low-grade coal for
25 adjusting a supply amount C2 of the pulverized coal of low-grade coal to be
conveyed into the supply tank; a pulverized coal pneumatic supply means for
pneumatically conveying the pulverized coal in the supply tank by a carrier gas
and supplying the pulverized coal to the tuyere; and a control means for
controlling the supply amount adjustment means for low-grade coal and the supply
30 amount adjustment means for high-grade coal so as to gradually increase the
supply amount C2 while maintaining the totall amount of the supply amount C1
and the supply amount C2 at a prescribed amount Ct.
The blast furnace installation pertaining to the second invention is a blast
furnace installation in which the pulverized coal supply means is equipped with a
35 carrier gas state detection means which detects at least one state among the
temperature, oxygen concentration, carbon monoxide concentration and carbon
dioxide concentration of the carrier gas near the tuyere; the pulverized coal
pneumatic supply means is equipped with an air feeding means for feeding air, an
air feed amount adjustment means for adjusting a feed amount GI of air from the
air feeding means, an inert gas feeding means for feeding inert gas, an inert gas
feed amount adjustment means for adjusting a feed amount G2 of inert gas from
5 the inert gas feeding means, and a supply line for supplying the pulverized coal by
pneumatic conveyance to the tuyere, by thf: carrier gas obtained by joining the air
from the air feeding means and the inert gas from the inert gas feeding means; and
the control means controls the air feed amount adjustment means and the inert gas
feed amount adjustment means based on information from the carrier gas state
10 detection means so as to bring the temperature Tg of the carrier gas in a range of
an upper limit value Tu to a lower limit value Td while maintaining the total
amount of a feed amount GI1 and feed amount G2 at a prescribed amount Gt in the
first invention.
The blast furnace installation pertaining to the third invention is a blast
15 furnace installation in which, based on information from the carrier gas state
detection means, the control means, upon the temperature Tg of the carrier gas
being equal to or less than the upper limit value Tu, controls the supply amount
adjustment means for low-grade coal so as to increase the supply amount C2 of the
pulverized coal of low-grade coal, and controls the supply amount adjustment
20 means for high-grade coal so as to decrease the supply amount C1 of the
pulverized coal of high-grade coal, and upon the temperature Tg of the carrier gas
being greater than the upper limit value Tu, controls the inert gas feed amount
adjustment means so as to increase the feed amount G2 of the inert gas, and
controls the air feed amount adjustment means so as to decrease the feed amount
25 GI1 of the air in the second invention.
The blast furnace installation pertaining to the fourth invention is a blast
furnace installation in which, based on information from the carrier gas state
detection means, the control means, upon the temperature Tg of the carrier gas
being equal to or greater than the lower limit value Td, controls the inert gas feed
30 amount adjustment means so as to increase the feed amount G2 of the inert gas,
and controls the air feed amount adjustment means so as to decrease the feed
amount GI of the air, and upon the temperature Tg of the carrier gas being less
than the lower limit value Tu, determines whether or not the supply amount @2 of
the pulverized coal of low-grade coal is the prescribed amount Ct, and upon the
35 supply amount C2 of the pulverized coal of low-grade coal being the prescribed
amount Ct, controls the air feed amount adjustment means and the inert gas feed
amount adjustment means so as to bring the temperature Tg of the carrier gas in a
range of the upper limit value Tu to the lower limit value Td, and upon the supply
amount C2 of the pulverized coal of low-grade coal not being the prescribed
amount Ct, controls the supply amount adjustment means for low-grade coal so as
to increase the supply amount C2 of the pulverized coal of low-grade coal, and
5 controls the supply amount adjustment means for high-grade coal so as to decrease
the supply amount C1 of the pulverized coal of high-grade coal in the second or
third invention.
The blast furnace installation pertaining to the fifth invention is a blast
furnace installation in which the pyrolysis means pyrolyzes the low-grade coal at
10 from 400 to 600°C in any one of the first to fourth inventions.
The blast furnace installation pertaining to the sixth invention is a blast
furnace installation in which the high-grade coal is anthracite coal or bituminous
coal, and the low-grade coal is sub-bituminous coal or lignite in any one of the
first to fifth inventions.
15 The blast furnace installation pertaining to a seventh invention is a blast
furnace installation in which the inert gas is at least one among nitrogen gas, offgas
discharged from the blast furnace body, and combustion exhaust gas after the
off-gas is combusted with air in any one of the first to sixth inventions.
20 Advantageous Effects of Invention
By the blast furnace installation pertaining to the present invention,
pulverized coal of inexpensive low-grade coal can be safely used as blowing coal
(PC% coal) and the production cost of pig iron can be reduced due to the fact that
blowing coal (PC1 coal) into the tuyere of the blast furnace body can be switched
25 from pulverized coal of high-grade coal to pulverized coal of low-grade coal even
while the blast furnace body is operating.
Brief Description of Drawings
FIG 1 is a schematic configuration diagram of essential parts on a
30 pulverized coal supply means side of a first embodiment of the blast furnace
installation pertaining to the present invention,
FIG. 2 is a schematic configuration diagram of essential parts on the blast
furnace body side of the first embodiment of the blast furnace installation
pertaining to the present invention.
35 FIG. 3 is a control block diagram of essential parts of the first embodiment
of the blast furnace installation pertaining to the present invention,
FIG. 4 is a control flow diagram of essential parts of the first embodiment
of the blast furnace installation pertaining to the present invention.
FIG. 5 is a schematic configuration diagram of essential parts on the blast
furnace body side of a second embodiment of the blast furnace installation
5 pertaining to the present invention.
FIG. 6 is a control block diagram of essential parts of the second
embodiment of the blast furnace installation pertaining to the present invention.
Description of Embodiments
10 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.

15 A first embodiment of the blast furnace installation pertaining to the present
invention will be described based on FIGS. 1 to 4.
As illustrated in FIG. 2, 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 in the conveyance direction of a charging conveyor 112 which
20 conveys the starting material 1. On the downstream side in the conveyance
direction of the charging conveyor 112, a throat hopper 113 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 115 provided on a
tuyere of the blast furnace body 1 10.
2 5 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 113 and the like; and a hot air blowing means is constituted by the hot air
feeding device 114, the blow pipe 11 5 and the like.
The distal side of an injection lance 11 6 is inserted and connected part way
30 along the blow pipe 115. To the proximal side of the injection lance 116, a blast
opening of an air blower 114, which serves as both an air feeding means for
feeding air 106 and an air feed amount adjustment means, is connected via a
supply line 11 9. Between the blast opening of the air blower 11 7 and the proximal
side of the injection lance 116 along the supply line 119, an nitrogen gas supply
35 source 121 (refer to FIG. I), which is an inert gas feeding means for feeding
nitrogen gas 102 which is an inert gas, is connected via a flow rate adjustment
valve 1 1 8 which is an inert gas feed amount adjustment means.
On the other hand, as illustrated in FIG 1, a storage tank 151 which stores
high-grade coal 12 such as anthracite coal or bituminous coal therein is disposed
near the blast furnace body 110. To the lower portion of the storage tank 15 1 is
connected the proximal side of a feeder 152 which dispenses the high-grade coal
5 12 stored in the storage tank 15 1. The distal side of the feeder 152 is connected to
the receiving port of a roller mill 153 which pulverizes the high-grade coal 12
(diameter equal to or less than 100 pm).
The outlet port of the roller mill 153 is connected to the receiving port of a
cyclone separator P 56 via a conveyor line 155. To the roller mill 153 is connected
10 to a burner 154 which feeds combustion gas 108 obtained by burning natural gas
108a or the like, such that the roller mill 153 can pulverize the high-grade coal 12
while drying the high-grade coal 12 by heating (approximately 250°C) by the
combustion gas fed from the burner 154, and pneumatically convey the pulverized
coal % 8 via the conveyor line 155 to the cyclone separator 156.
1 5 Furthermore, a steam-tube-dryer-type drying device 1 22, which evaporates
moisture 3 in low-grade coal 2 such as sub-bituminous coal or lignite, is disposed
near the blast furnace body 110, and, by means of the nitrogen gas 102 from the
nitrogen gas supply source 121 being fed to the interior and steam 103 which is a
heating medium being fed to the interior of a coil heating pipe disposed in the
20 center portion, this drying device 1 22 is conf gured to be able to heat (from 100 to
200°C) the low-grade coal 2 supplied from the hopper 122a while maintaining the
interior in a low-oxygen atmosphere (approximately several percent) to remove
moisture 3 and volatile components 4 that are volatilized at a relatively low
temperature from the low-grade coal 2 to produce dried coal 5, and at the same
25 time, to discharge this moisture 3 and these volatile components 4 together with
the nitrogen gas 102 to the exterior.
The discharge port for the dried coal 5 of the drying device 122 is
connected via a rotary valve 13 1 to the upstream side in the conveyance direction
of a conveyor 141 having a shield hood that covers the periphery. Nitrogen gas
30 102 from the nitrogen gas supply source 121 is fed inside the shield hood of the
conveyor 141, to result in a nitrogen gas atmosphere inside the shield hood of the
conveyor 14 1.
The downstream side in the conveyance direction of the conveyor 141 is
connected via a rotary valve 132 to the receiving port for the dried coal 5 of a
35 rotary kiln-type pyrolysis device 123 which pyrolyzes the dried coal 5, and, by
means of the nitrogen gas 102 from the nitrogen gas supply source 121 being fed
to the interior and combustion gas 104 which is a heating medium being fed to an
external jacket supported in a fixed manner, this pyrolysis device 123 ir;
configured to be able to heat (from 400 to 600°C) the dried coal 5 ~111ile
maintaining the interior in a nitrogen gas atmosphere to remove volatile
components 6 that are volatilized at a relatively high temperature from the dried
5 coal 5 to produce pyrolyzed coal 7, and at the same time, to discharge these
volatile components 6 together with the nitrogen gas 102 to the exterior.
The discharge port for the pyrolyzed coal 7 of the pyrolysis devicc 123 is
connected via a rotary valve 133 to the upstream side in the conveyance direction
of a conveyor 142 having a shield hood that covers the periphery. Nitrogen gas
10 102 from the nitrogen gas supply source 121 is fed inside the sl~ield hood of the
conveyor 142, to result in a nitrogen gas atmosphere inside the shield hood of the
conveyor 142.
The downstream side in the conveyance direction of the conveyor 142 is
connected via a rotary valve 134 to the receiving port for the pyrolyzcd coal 7 of
15 a steam-tube-dryer-type cooling device 124 which cools the pyrolyzed coal 7, and,
by means of the nitrogen gas 102 from the nitrogen gas supply source 121 being
fed to the interior and cooling water 105 which is a cooling medium being fed to
the interior of a coil cooling pipe disposed in the center portion, this cooling
device 124 is configured to be able to cool (equal to or less than 200°C) the
20 pyrolyzed coal 7 while maintaining the interior in a nitrogen gas atmosphere.
The discharge port for the pyrolyzed coal 7 of the cooling device 124 is
connected via a rotary valve 135 to the upstream side in the conveyance direction
of a conveyor 143 having a shield hood that covers the periphery. Nitrogen gas
102 from the nitrogen gas supply source 121 is fed inside the shield hood of the
25 conveyor 143, to result in a nitrogen gas atmosphere inside the shield hood of the
conveyor 143.
The downstream side in the conveyance direction of the conveyor 143 is
connected via a rotary valve 136 to the receiving port for pyrolyzed coal '7 of a
mill-type pulverization device 125 which pulverizes the pyrolyzed coal '7, and the
30 pulverization device 125 is configured to be able to pulverize the pyrolyzed coal 7
while maintaining the interior in a nitrogen gas atmosphere by nitrogen gas fed
together with the pyrolyzed coal 7, to provide pulverized coal 8 (diameter equal to
or less than 1 00 pm).
The lower portion of the pulverization device 125 is connected via a rotary
35 valve 137 to the upper portion of a storage tank 126 which stores the pulverized
coal 8, and this storage tank 126 is configured to be able to maintain the interior in
a nitrogen gas atmosphere. To the lower portion of the storage tank 126 is
connected the proximal side of a feeder 127 which dispenses the pulverized coal 8
stored in the storage tank 126. 'The distal side of the feeder 127 is connected part
way along the conveyor line 128 extending from the nitrogen gas supply source
121. The conveyor line 128 is connected to the receiving port of a cyclone
5 separator 129.
The lower portions of the cyclone separators 129, 156 are connected above
a supply tank 120 into which the pulverized coals 8, 18 are put, and the supply
tank 120 is configured to be able to maintain the interior in a nitrogen gas
atmosphere, and to supply the pulverized coals 2, 18 by dropping from the interior.
10 As illustrated in FIGS. 1 and 2, the lower portion of the supply tank 120 is
connected between the air blower 11 7 and the flow rate adjustment valve 11 8, and
the injection lance 1 16 along the supply line 119, and, by means of a carrier gas
107 obtained by joining the air 106 from the air blower and the nitrogen gas 102
from the nitrogen gas supply source 121, the supply line 1 19 is configured to be
15 able to pneumatically convey the pulverized coals 8, 18 supplied by being dropped
from the interior of the supply tank 120 from the injection lance 1 16 to the blow
pipe 115, to supply the pulverized coals 8, 18 to the tuyere.
As illustrated in FIG. 2; near the proximal side of the injection lance 11 6,
that is, near the tuyere, a temperature sensor 161, whicla is a carrier gas state
20 detection means for detecting the temperature inside the injection lance 116, is
provided. As illustrated in FIG. 3, the temperature sensor 161. is electrically
connected to the input part of a control unit 160 which is a control means. The
respective output parts of the control unit 160 are electrically connected to the air
blower 117, the flow rate adjustment valve 118, and the feeders 127, 152? and, on
25 the basis of information from the temperature sensor 161 or the like, the control
unit 160 is configured to be able to control each of the blast volume of the air
blower 1 17, the openness of the flow rate adjustment valve 11 8, and the supply
amounts of the pulverized coals 8, 18 by the feeders 127, 152 (details will be
described below).
30 In this embodiment, a moisture removal means for low-grade coal is
constituted by the nitrogen gas supply source 121, the drying device 122, the
rotary valve 13 1 and the like; a pyrolysis means is constituted by the nitrogen gas
supply source 121, the pyrolysis device 123, the rotary valves 132, 133, the
conveyor 141 and the like; a cooling means is constituted by the nitrogen gas
35 supply source 121, the cooling device 124, the rotary valves 134, 135, the
conveyor 142 and the like; a pulverization means for low-grade coal is constituted
by the nitrogen gas supply source 121, the pulverization device 125, the rotary
valve 136, the conveyor 143 and the like; a supply amount adjustment means for
low-grade coal is constituted by the storage tank 126, the feeder 127, the rotary
valve 136 and the like; a conveying means for low-grade coal is constituted by the
nitrogen gas supply source 121, the conveyor line 128, the cyclone separator 129
5 and the like; a supply amount adjustment means for high-grade coal is constituted
by the storage tank 15 1, the feeder 152 and the like; a moisture, removal means for
high-grade coal, a pulverization means for high-grade coal and a conveying means
for high-grade coal are together constituted by the roller mill 153, the burner 154,
the conveyor line 155, the cyclone separator 156 and the like; and a pulverized
10 coal pneumatic supply means is constituted by the blow pipe 115, the injection
lance 116, the air blower 117, the flow rate adjustment valve 11 8, the supply line
119, the nitrogen gas supply source 121 and the like. Furthermore, in FIG. 1, 11 0a
is a taphole for drawing out melted pig iron (molten iron).
Now, the operation of the blast furnace installation 100 pertaining to this
15 embodiment will be described,
When the starting material 1 is dispensed from the starting material
dispensing device 111, the starting material 1 is supplied into the throat hopper
113 by the charging conveyor 112, and charged into the blast furnace body 110.
Additionally, when the control unit 160 is operated, the control unit 160
20 operates and controls the air blower 117 such that feed amount G1 of air 106 from
the air blower 117 is a prescribed amount Gt, and operates and controls the supply
rate of the feeder 152 such that supply amount C1 of high-grade coal 12 from
inside the storage tank 1.5 1 to the roller mill 153 is a prescribed amount Ct (S11 in
4).
2 5 The high-grade coal 12 supplied from the feeder 152 is pulverized in the
roller mill 153 while being dried by heating by combustion gas 108
(approximately 250°C) from the burner 154, to result in pulverized coal 18
(diameter equal to or less than 100 pm), which is pneumatically conveyed to the
cyclone separator 156 via the conveyor line 155. The pulverized coal 18
30 pneumatically conveyed to the cyclone separator 156 is separated from the
combustion gas 108 and put into the supply tank 120.
The pulverized coal 18 that has been put into the supply tank 120 is
supplied by being dropped a fixed amount at a time, and then pneumatically
conveyed to the injection lance 116 via the supply line 119 by carrier gas 107
35 constituted by the air 11 06 from the air blower 117, and then supplied to the interior
of the blow pipe 115 together with the carrier gas 1107, and supplied into the hot air
101 fiom the hot air feeding device 114, thereby being burned.
The pulverized coal 18 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
5 result in pig iron (molten iron) 9, which is drawn out from the taphole 110a.
On the other hand, when the nitrogen gas 102 from the nitrogen gas supply
source 121 is fed and the low-grade coal 2 is supplied to the interior of the drying
device 122 from the hopper 122a of the drying device 122, this low-grade coal 2 is
heated (at from 100 to 200°C) via the heating pipe by the steam 103 in a low-
10 oxygen atmosphere (approximately several percent), and the moisture 3 and the
volatile components 4 evaporate and are discharged outside the system together
with the nitrogen gas 102, and the low-grade coal 2 is thereby dried to provide
dried coal 5.
Furthermore, the nitrogen gas 102 that contains the volatile components 4 is
15 utilized as the combustion gas 104 by means of combustion treatment in a
combustion furnace (not illustrated), and then undergoes cleaning treatment.
The dried coal 5 is supplied to the conveyor 141 via the rotary valve 13 1
and conveyed in a nitrogen gas atmosphere, and is then supplied to the interior of
the pyrolysis device 123 via the rotary valve 132, and then heated (at from 400 to
20 600°C) via the heating pipe by the combustion gas 104 in a nitrogen gas
atmosphere, and the volatile components 6 evaporate and are discharged outside
the system together with the nitrogen gas 102, and the dried coal 5 is thereby
pyrolyzed to provide pyrolyzed coal 7 which is highly reactive with oxygen.
Furthermore, the nitrogen gas 102 that contains the volatile components 6 is
25 utilized as the combustion gas 104 by means of combustion treatment in a
combustion furnace (not illustrated), and then undergoes cleaning treatment.
The pyrolyzed coal 7 is supplied to the conveyor 142 via the rotary valve
133 and conveyed in a nitrogen gas atmosphere, and is then supplied to the interior
of the cooling device 124 via the rotary valve 134, and then cooled (at equal to or
30 less than 200°C) via the cooling pipe by the cooling water 105 in a nitrogen gas
atmosphere, after which it is supplied to the conveyor 143 via the rotary valve 135
and conveyed in a nitrogen gas atmosphere, and then supplied to the interior of the
pulverization device 125 via the rotary valve 136, and pulverized (diameter equal
to or less than 100 pm) in a nitrogen gas atmosphere, thereby providing pulverized
35 coal$.
The pulverized coal 8 is supplied to the interior of the storage tank 126 via
the rotary valve 137, and temporarily held in a nitrogen gas atmosphere.
In this manner, the blast furnace body 110 is operated while the pulverized
coal 18 constituted by the high-grade coal 12 is blown into the blast furnace body
110, and when a prescribed time has elapsed, the control unit 160 operates and
controls the supply rate of the feeder 127 such that the pulverized coal 8 is
5 supplied from inside the storage tank 126 in supply amount C2, and operates and
controls the supply rate of the feeder 152 so as to decrease supply amount C1 of
the pulverized coal 18 from inside the storage tank 151 by the supply amount C2
of the pulverized coal 8 (C 1 = Ct - C2) (S 12 in FIG. 4).
The pulverized coal 8 supplied in supply amount C2 from the feeder 127 is
10 pneumatically conveyed to the cyclone separator 129 via the conveyor line 128 by
nitrogen gas 102 from the nitrogen gas supply source 12 1, and after the nitrogen
gas 102 is separated, is put into the supply tank 120.
As a result, a mixture of the pulverized coal 18 in supply amount C1
constituted by the high-grade coal 12 and the pulverized coal 8 in supply amount
15 C2 constituted by the low-grade coal 2 is put into the supply tank 120 in the
prescribed amount Ct (= C1 + C2).
The pulverized coals 8, 18 that have been mixed in the supply tank 120, as
previously described, are supplied by being dropped a fixed amount at a time, and
then pneumatically conveyed to the injection lance 1 16 via the supply line 1 19 by
20 means of the carrier gas 107 constituted by the air 106 from the air blower 11 7.
At this time, because the pulverized coal 8 constituted by the low-grade
coal 2 has been increased in reactivity by being pyrolyzed and because the carrier
gas 107 contains oxygen (approximately 21 vol%), a portion of the pulverized coal
8 reacts with oxygen and burns during pneumatic conveyance. For this reason, the
25 carrier gas 107 and the pulverized coals 8, 18 have their temperatures increased by
self-heating,
Then, on the basis of information from the temperature sensor 161, the
control unit 160 determines whether or not temperature Tg of the carrier gas 107 is
equal to or less than an upper limit value Tu (S 13 in FIG. 4).
3 0 If the temperature Tg of the carrier gas 107 is equal to or less than the
upper limit value Tu (Tg 5 Tu), the control unit 160 operates and controls the
supply rate of the feeder 127 so as to further increase the supply amount C2 of the
pulverized coal 8 from inside the storage tank 126, and operates and controls the
supply rate of the feeder 152 so as to decrease the supply amount C1 of the
35 pulverized coal 11 8 from inside the storage tank 15 1 by the amount of increase of
the pulverized coal 8 (C1 = Ct - C2) (S14 in FIG 4).
On the other hand, if the temperature Tg of the carrier gas 107 is greater
than the upper limit value Tu (Tg > Tu), the control unit 160 operates and controls
the openness of the flow rate adjustment valve 118 so as to feed the nitrogen gas
102 in feed amount G2 from the nitrogen gas supply source 121, and operates and
5 controls the air blower 117 so as to decrease feed amount G1 of the air 106 from
the air blower 117 by the feed amount G2 of the nitrogen gas 102 (GI = Gt - G2)
(S15 in FIG. 4).
As a result, the oxygen concentration of the carrier gas 107 which
pneumatically conveys the pulverized coals 8, 18 decreases, and the amount of the
10 pulverized coal 8 that reacts with oxygen and burns while being pneumatically
conveyed decreases, and therefore, a temperature rise of the carrier gas 107 and
the pulverized coals 8, 18 is suppressed.
Next, on the basis of information from the temperature sensor 161, the
control unit 160 determines whether or not the temperature Tg of the carrier gas
15 107 is equal to or greater than a lower limit value Td (S16 in FIG. 4).
If the temperature Tg of the carrier gas 107 is equal to or greater than the
lower limit value Td (Tg 2 Td), the control unit 160 operates and controls the
openness of the flow rate adjustment valve 118 so as to increase the feed amount
G2 of the nitrogen gas 102 from the nitrogen gas supply source 121, and operates
20 and controls the air blower 117 so as to decrease the feed amount G1 of the air 106
from the air blower 117 by the amount of the increase of the nitrogen gas 102 (GI
= Gt - G2) (S17 in FIG. 4).
On the other hand, if the temperature Tg of the carrier gas 107 is less than
the lower limit value Td (Tg < Td), the control unit 160 determines whether or not
25 the supply amount C2 of the pulverized coal 8 from inside the storage tank 126 is
the prescribed amount Ct (C2 = Ct), that is, whether or not the supply amount C1
of the pulverized coal 4 8 from inside the storage tank 15 1 is zero (C 1 = 0) (S 18 in
FIG. 4).
If the supply amount C2 is the prescribed amount Ct (C2 = Ct), that is, the
30 supply amount C1 is zero (C1 = 0), in other words, if the blowing coal (PC1 coal)
to the tugrere of the blast furnace body 110 has been switched from the pulverized
coal 18 of the high-grade coal 12 to the pulverized coal 8 of the low-grade coal 2,
the control unit 160, on the basis of information from the temperature sensor 161,
operates and controls the flow rate adjustment valve 11 8 and the air blower 11 7 so
35 as to bring the temperature Tg of the carrier gas 107 in a range of the upper limit
value Tu to the lower limit value Td, thereby adjusting the oxygen concentration
of the carrier gas 107 while feeding the carrier gas 107 in the prescribed amount
Gt (S19 in FIG 4),
On the other hand, if the supply amount C2 is not the prescribed amount Ct
(C2 # Ct), that is, the supply amount C1 is not zero (C1 f 0), the control unit 160
returns to step S14 and repeats the steps described above.
In short, a conventional blast furnace installation uses only pulverized coal
18 of high-grade coal 12, such as high-quality, expensive anthracite coal or
bituminous coal, as blowing coal (pulverized coal injection: PC1 coal). In the blast
furnace installation 100 pertaining to this embodiment, however, low-grade coal 2
such as sub-bituminous coal or lignite is turned into pyrolyzed coal 7 which is
highly reactive with oxygen (reactivity with oxygen approximately 20 times that
of low-grade coal 2) by being dried and pyrolyzed. Then, in a nitrogen gas
atmosphere, pulverized coal 8 which has been cooled and pulverized is conveyed
by a nitrogen gas stream and supplied into the supply tank 120 having a nitrogen
gas atmosphere. While maintaining the total amount of the supply amount C1 of
the pulverized coal 18 of high-grade coal 12 and the supply amount C2 of the
pulverized coal 8 of low-grade coal 2 at the prescribed amount Ct, the pulverized
coal 8 is pneumatically conveyed by the carrier gas 107 from inside the supply
tank 120 while gradually increasing the supply amount C2 of the pulverized coal 8
of low-grade coal 2, thereby allowing the pulverized coal 8 to be safely used as
blowing coal (PC1 coal) while gradually switching the pulverized coal 18 to the
pulverized coal 8 obtained by imparting high combustion characteristics to
inexpensive low-grade coal 2.
For this reason, in the blast furnace installation 100 pertaining to this
embodiment, blowing coal (PC1 coal) into the tuyere of the blast furnace body 11 0
can be switched from the pulverized coal 18 of high-grade coal 12 to the
pulverized coal 8 of low-grade coal 2 while the blast furnace body 110 is operating
and without causing abnormal combustion in the pulverized coal 8.
Therefore, by the blast furnace installation 100 pertaining to this
embodiment, the production cost of pig iron 9 can be reduced due to the fact that
pulverized coal 8 of inexpensive low-grade coal 2 can be safely used as blowing
coal (PC% coal).
Additionally, the ignitability of the pulverized coals 8, 18 can be sped up
and burn-out capability can be improved because the carrier gas 107 and the
pulverized coals 8, 18 can be preheated by self-heating accompanying the reaction
of the pulverized coal 8 with oxygen.
Furthermore, with improvement of ignitability (burn-out capability) of the
blowing coal (PC1 coal), the supply amount 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
5 coal), the supply amount of blowing coal (PC1 coal) may be increased, and
therefore the amount of coal (coke) to be supplied as the 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.
Furthermore, as the upper limit value Tu of the temperature Tg of the
10 carrier gas 107, the pyrolysis temperature of the low-grade coal 2 (from 400 to
600°C) is preferred, and, in particular, a temperature lower by about 100°C than
the pyrolysis temperature (from 300 to 500°C) is more preferred. This is because if
the upper limit value Tu is greater than the pyrolysis temperature, there is risk of
thermolysis products such as tar being produced from the pulverized coal 8, and
15 these thermolysis products adhering to the inner wall surface of the injection lance
116 and the like, and blocking the injection lance 116 and the like.
As the lower limit value Td of the temperature Tg of the carrier gas 107,
200°C is preferred, and, in particular, a temperature lower by from about 50 to
100°C than the upper limit value Tu (from 200 to 450°C) is more preferred. This
20 is because if the lower limit temperature Td 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 8. Here, if the temperature is lower by from about 50 to 100°C
than the upper limit value Tu (from 200 to 450°C), the control allowance of rising
and lowering temperature can be within the required sufficient range, reducing
25 waste in energy and time.
Furthermore, it is preferred that the control unit 160 adjust the supply
amount C2 (increase amount) of the pulverized coal 8 and the feed amount G2
(increase amount) of the nitrogen gas 102, in order words, the supply amount C1
(decrease amount) of the pulverized coal 18 and the feed amount G1 (decrease
30 amount) of the air 106 while controlling the feeders 127, 152, the flow rate
adjustment valve 118 and the air blower 117 on the basis of information from the
temperature sensor 161 such that a temperature rise (temperature rising rate) per
unit time of the temperature Tg of the carrier gas 107 is within a prescribed range.
35
A second embodiment of the blast furnace installation pertaining to the
present invention will be described based on FIGS. 5 and 6, 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 duplicates of those in the embodiment above are omitted.
As illustrated in FIG. 5, the proximal side of a fractionation line 263 is
5 connected near the proximal end of the injection lance 116 between the injection
lance 116 and the supply tank 120 along the supply line 119. The distal side of the
fractionation line 263 is connected to one port of a three-way valve 264. The
remaining two ports of the three-way valve 264 are respectively connected to filter
devices 265A, 265B.
10 The outlet ports of the filter devices 265A, 265B are connected to the
suction port of a suction pump 266. The outlet port of the suction pump 266 is
connected via a return line 267 between the proximal side of the fractionation line
263 and the proximal side of the injection lance 1 16. A CO sensor 26 1 which
detects the carbon monoxide concentration in the carrier gas 107 fractionated from
15 the fractionation line 263 is provided between the outlet ports of the filter devices
265A, 265B and the suction port of the suction pump 266.
As illustrated in FIG. 6, the CO sensor 261 is electrically connected to the
input part of the control unit 260 which is the control means. The respective output
parts of the control unit 260 are electrically connected to the air blower 117, the
20 flow rate adjustment valve 118, and the feeders 127, 152, and, on the basis of
information from the CO sensor 261 or the like, the control unit 260 is configured
to be able to control each of the blast volume of the air blower 117, the openness
of the flow rate adjustment valve 118, and the supply amounts of the pulverized
coals 8, 18 by the feeders 127, 152 (details will be described later).
25 Furthermore, in this embodiment, a carrier gas state detection means is
constituted by the CO sensor 26 1, the fractionation line 263, the three-way valve
264, the filter devices 265A and 265B, the suction pump 266, the return line 267
and the like.
In the blast furnace installation 200 pertaining to this embodiment, similar
30 to the embodiment described above, while the starting material 1 is charged into
the blast furnace body 110, the three-way valve 264 is opened and closed such that
only one of the filter devices 265A, 265B (for example, filter device 265A) is
connected to the fractionation line 263 and the return line 267, and the suction
pump 266 is operated and the control unit 260 is operated. Then, the control unit
35 260, similar to the embodiment described above, operates and controls the air
blower 117 so as to feed the air 106 from the air blower 117 such that the feed
amount G1 is the prescribed amount Gt, and operates and controls the supply rate
of the feeder 152 so as to supply the high-grade coal 12 from inside the storage
tank 151 to the roller mill 153 such that the supply amount CI is the prescribed
amount Ct.
The high-grade coal 12 supplied from the feeder 152, similar to the
5 embodiment described above, becomes pulverized coal 18 which is pneumatically
conveyed, separated from the combustion gas 108 via the cyclone separator 156,
and put into the supply tank 120,
The pulverized coal 18 that has been put into the supply tank 120, similar to
the embodiment described above, is supplied by being dropped a fixed amount at a
10 time, and then pneumatically conveyed to the injection lance 116 via the supply
line 119 by the carrier gas 107 constituted by the air 106 from the air blower 117,
and then supplied to the interior of the blow pipe 11 5 together with the carrier gas
107, and supplied into the hot air 101 from the hot air feeding device 114, thereby
being burned.
1 5 The pulverized coal 18 that has been burned in the interior of the blow pipe
115, similar to the embodiment described above, 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.
On the other hand, similar to the embodiment described above, the
20 pulverized coal 8 is produced by drying, pyrolyzing, cooling and pulverizing the
low-grade coal 2, and this pulverized coal 8 is stored temporarily in a nitrogen gas
atmosphere in the storage tank 126.
Then, the blast furnace body 110 is operated while the pulverized coal 18
constituted by the high-grade coal 12 is blown into the blast furnace body 110, and
25 when a prescribed time has elapsed, the control unit 260, similar to the
embodiment described above, operates and controls the supply rate of the feeder
127 such that the pulverized coal 8 is supplied from inside the storage tank 126 in
the supply amount C2, and operates and controls the supply rate of the feeder 152
so as to decrease the supply amount C1 of the pulverized coal 18 from inside the
30 storage tank 151 by the supply amount C2 of the pulverized coal 8 (Cf = Ct - C2).
The pulverized coal 8 supplied from the feeder 127 in the supply amount
C2, similar to the embodiment described above, is pneumatically conveyed by the
nitrogen gas 102, separated from the nitrogen gas 102 via the cyclone separator
129, and put into the supply tank 120.
3 5 As a result, similar to the embodiment described above, a mixture of the
pulverized coal 18 in the supply amount C1 constituted by the high-grade coal 12
and the pulverized coal 8 in the supply amount C2 constituted by the low-grade
coal 2 is put into the supply tank 120 in the prescribed amount Ct (= C1 + C2).
The pulverized coals 8, 18 that have been mixed in the supply tank 120,
similar to the embodiment described above, are supplied by being dropped a fixed
5 amount at a time, and then pneun~atically conveyed to the injection lance 116 via
the supply line 11 9 by means of the carrier gas 107 constituted by the air 106 from
the air blower 11 7.
At this time, similar to the embodiment described above, because the
pulverized coal 8 constituted by the low-grade coal 2 has been increased in
10 reactivity by being pyrolyzed and because the carrier gas 107 contains oxygen
(approximately 21 vol%), a portion of the pulverized coal 8 reacts with oxygen
and burns during pneumatic conveyance. For this reason, the carrier gas 107 and
the pulverized coals 8, 18 have their temperatures increased by self-heating.
Here, the carrier gas 107 that has been pneumatically conveyed to near the
15 proximal side of the injection lance 116 is partially fractionated into the
fractionation line 263 from the supply line 119 by the suction pump 266 and
passes through the three-way valve 264, and after the pulverized coals 8, 18 and
the like are removed by the filter device 265A, the carbon monoxide concentration
is detected by the CO sensor 261, and the carrier gas 107 is then returned from the
20 return line 267 via the suction pump 266 to the supply line 11 9.
Then, the control unit 260 controls the blast volume of the air blower 117
and the openness of the flow rate adjustment valve 11 8 on tlze basis of information
from the CO sensor 261. Specifically, the carbon monoxide concentration in the
carrier gas 107 is a value substantially determined by the type of the pulverized
25 coals 8, 18 (coal type), the supply amount of the pulverized coals 8, 18, the
oxygen concentration in the carrier gas 107, and the temperature of the carrier gas
107.
For this reason, the temperature Tg of the carrier gas 107 can be determined
by detecting the carbon monoxide concentration in the carrier gas 107 since the
30 supply amount and type of the pulverized coals 8, 18 are predetermined and the
oxygen concentration in the carrier gas 107 can be calculated.
As a result, the control unit 260 calculates the temperature Tg of the carrier
gas 107 on the basis of information from the CO sensor 261, that is, the carbon
monoxide concentration of sampled carrier gas 107, in other words, the carbon
35 monoxide concentration in the carrier gas 107 near the tuyere, and, similar to the
embodiment described above, controls the air blower 11 7, the flow rate adjust~nent
valve 118 and the feeders 127, 152 on the basis of the upper limit value Tu and
lower limit value Td of the temperature Tg of the carrier gas 107, the supply
amount C2 of the pulverized coal 8, and the like.
Furthermore, since the filter device 265A gradually becomes clogged due to
sampling of the carrier gas 107, sampling of the carrier gas 107 can be
continuously performed by, after a prescribed time has elapsed, opening and
closing the three-way valve 264 so as to connect only the filter device 265B to the
fractionation line 263 and the return line 267, and replacing the filter device 265A
with a new one.
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 161 provided near the proximal side of the injection lance 116,
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
260 by sampling the carrier gas 107 near the proximal side of the injection lance
116 into a sampling line and detecting its carbon monoxide concentration by the
CO sensor 26 1.
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 detecting part of a sensor or the like into the line through which the
majority of the carrier gas 107 flows.
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 coals 8, 18 to the
detecting 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
1 16 can be suppressed beforehand.

In the first and second embodiments described above, the case where the
drying device 422 and the cooling device 124 have steam tube dryers employed
therein has been described, but as another embodiment, it is also possible to
employ, for example, a rotary kiln similar to the pyrolysis device 123 in the drying
device and cooling device.
Furthermore, in the first and second embodiments described above, the case
where nitrogen gas 102 is fed from the nitrogen gas supply source 121 has been
described, but as another embodiment, for example, blast furnace off-gas
(approximately 200°C) discharged from the blast furnace body 11 0, or combustion
exhaust gas (approximately 100°C) of the blast furnace off-gas, which has been
generated after the blast furnace off-gas is combusted together with air and has
been used as a heat source of the hot air 101, may be used as an inert gas instead
of the nitrogen gas 102. That is, the blast furnace body 110 or the hot air feeding
5 device 114 or the like may also be used as an inert gas supply source.
Additionally, in the first and second embodiments described above,
combustion gas 108 obtained by burning the natural gas 108a by the burner 154 is
fed to the roller mill 153 to dry the high-grade coal 12 and is used as gas for
pneumatically conveying the pulverized coal 18, but as another embodiment, the
10 consumption amount of the natural gas 108a can be greatly decreased and costs
can be further reduced if, for example, after the combustion gas 104 which has
been used in heating for pyrolysis in the pyrolysis device 123 is subjected to heat
recovery and moisture removal by a heat exchanger or the like, the combustion gas
104 is fed to the roller mill 153, that is, the combustion gas 104 is used instead of
15 the combustion gas 108.
Furthermore, in the second embodiment described above, the temperature
Tg of the carrier gas 107 is determined by detecting the carbon monoxide in the
carrier gas 107 by the CO sensor 26 1, but as another embodiment, the temperature
Tg of the carrier gas 107 can also be determined by employing, for example, a COz
20 sensor that detects the carbon dioxide concentration or an 0 2 sensor that detects
the oxygen concentration in the carrier gas 107, instead of the CO sensor 261.
Furthermore, in the case where the storage tank 151 which stores the highgrade
coal 12 is extremely large and is equipped with a plurality of (for example,
two) parallel feeders 152, roller mills 153, burners 154, cyclone separators 156
25 and the like, it is possible to omit the cyclone separator 129 and to reduce
installation space by, for example, connecting the conveyor line 128 and the like
such that at least one of the cyclone separators 156 can be used instead of the
cyclone separator 129.
In this case, the following configurations, for example, are preferred.
(1) The gas outlet port of the cyclone separator 156 is connected to the
conveyor line 128 via a recirculating line having a blower or the like, so that
nitrogen gas 102 discharged from the cyclone separator 156 used instead of the
cyclone separator 129 can be reused.
(2) For the cyclone separator 156 used instead of the cyclone separator 129
35 in above-described (I), to prevent mixing of oxygen gas in the conveyor line 128
when switching from the pulverized coal 18 of high-grade coal 12 to the
pulverized coal 8 of low-grade coal 2, an O2 sensor is provided in the recirculating
line, and the pulverized coal 8 is supplied to the conveyor line 128 after the
nitrogen gas 102 from the nitrogen gas supply source 121 is made to flow until the
0 2 concentration in the gas flowing through the recirculating line reaches a value
equal to or less than a prescribed value.
5 (3) For the cyclone separator 156 used instead of the cyclone separator 129
in above-described (I), in the case where the pulverized coal 18 of high-grade coal
12 and the pulverized coal 8 of low-grade coal 2 are supplied in parallel, an O2
sensor, CO sensor, CO:! sensor, temperature sensor or the like is provided in the
recirculating line, and nitrogen gas 102 is made possible to be additionally
10 supplied to the conveyor line 155 and the burner 154 which produces the
combustion gas 108 which pneumatically conveys the pulverized coal 18 to the
cyclone separator 156, and, based on inforination from the sensor, the oxygen
concentration (temperature) in the cyclone separator 129, the conveyor line 128, or
the like is made to be equal to or less than a prescribed value.
15
Industrial Applicability
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.
20
We Claim:
1. A blast furnace installation comprising:
a blast furnace body;
starting material charging means for charging a starting material
from a top into an interior of the blast furnace body;
hot air blowing ineans for blowing hot air into the blast furnace body
from a tuyere; and
pulverized coal supply means for supplying pulverized coal into the
blast furnace body through the tuyere; wherein
the pulverized coal supply means includes:
moisture removal means for high-grade coal for evaporating
moisture in high-grade coal;
pulverization means for high-grade coal for pulverizing the highgrade
coal, moisture in the high-grade coal having been removed by the
moisture removal means for high-grade coal, to provide pulverized coal;
moisture removal means for low-grade coal for evaporating moisture
in low-grade coal;
pyrolysis means for pyrolyzing the low-grade coal, moisture in the
low-grade coal having been removed by the moisture removal ineans for
low-grade coal;
cooling means for cooling the low-grade coal, the low-grade coal
having been pyrolyzed by the pyrolysis means;
pulverization means for low-grade coal for pulverizing the low-grade
coal, the low-grade coal having been cooled by the cooling means, to
provide pulverized coal;
a supply tank having an interior maintained in an inert gas
atmosphere and having the pulverized coal of high-grade coal and the
pulverized coal of low-grade coal put therein, the pulverized coal of highgrade
coal and the pulverized coal of low-grade coal being obtained
through pulverization by the pulverization means for high-grade coal and
the pulverization means for low-grade coal;
conveying means for high-grade coal for conveying the pulverized
coal of high-grade coal into the supply tank, the pulverized coal of highgrade
coal being obtained through pulverization by the pulverization means
for high-grade coal;
supply amount adjustment means for high-grade coal for adjusting a
supply amount C1 of the pulverized coal of high-grade coal to be conveyed
into the supply tank;
conveying means for low-grade coal for pneumatically conveying the
pulverized coal of low-grade coal into the supply tank by an inert gas, the
pulverized coal of low-grade coal being obtained through pulverization by
the pulverization means for low-grade coal;
supply amount adjustment means for low-grade coal for adjusting a
supply amount C2 of the pulverized coal of low-grade coal to be conveyed
into the supply tank;
pulverized coal pneumatic supply means for pneumatically
conveying the pulverized coal in the supply tank by a carrier gas and
supplying the pulverized coal to the tuyere; and
control means for controlling the supply amount adjustment means
for low-grade coal and the supply amount adjustment means for high-grade
coal so as to gradually increase the supply amount C2 while maintaining a
total amount of the supply amount C1 and the supply amount C2 at a
prescribed amount Ct,
The blast furnace installation according to claim 1, wherein
the pulverized coal supply means includes carrier gas state detection
means for detecting at least one among temperature, oxygen concentration,
carbon monoxide concentration, and carbon dioxide concentration of the
carrier gas near the tuyere;
the pulverized coal pneumatic supply means includes:
air feeding means for feeding air;
air feed amount adjustment means for adjusting a feed amount G1 of
air from the air feeding means;
inert gas feeding means for feeding inert gas;
inert gas feed amount adjustment means for adjusting a feed amount
G2 of inert gas from the inert gas feeding means; and
a supply line for supplying, to the tuyere, the pulverized coal by
pneumatic conveyance by the carrier gas obtained by joining the air from
the air feeding means and the inert gas from the inert gas feeding means;
and
the control means, based on information from the carrier gas state
detection means, controls the air feed amount adjustment means and the
inert gas feed amount adjustment means so as to bring temperature Tg of
the carrier gas in a range of an upper limit value Tu to a lower limit value
Td while maintaining a total amount of the feed amount G1 and the feed
amount G2 at a prescribed amount Gt.
5
3. The blast furnace installation according to claim 2, wherein
based on information from the carrier gas state detection means,
the control means, upon the temperature Tg of the carrier gas being
equal to or less than the upper limit value Tu, controls the supply amount
adjustment means for low-grade coal so as to increase the supply amount
C2 of the pulverized coal of low-grade coal, and controls the supply amount
adjustment means for high-grade coal so as to decrease the supply amount
C1 of the pulverized coal of high-grade coal; and
the control means, upon the temperature Tg of the carrier gas being
greater than the upper limit value Tu, controls the inert gas feed amount
adjustment means so as to increase the feed amount G2 of the inert gas, and
controls the air feed amount adjustment means so as to decrease the feed
amount GI of the air.
20 4. The blast furnace installation according to claim 2, wherein
based on information from the carrier gas state detection means,
the control means, upon the temperature Tg of the carrier gas being
equal to or greater than the lower limit value Td, controls the inert gas feed
amount adjustment means so as to increase the feed amount G2 of the inert
gas, and controls the air feed amount adjustment means so as to decrease
the feed amount GI of the air;
the control means, upon the temperature Tg of the carrier gas being
less than the lower limit value Tu, determines whether or not the supply
amount C2 of the pulverized coal of low-grade coal is the prescribed
amount Ct;
the control means, upon the supply amount C2 of the pulverized coal
of low-grade coal being the prescribed amount Ct, controls the air feed
amount adjustment means and the inert gas feed amount adjustment means
so as to bring the temperature Tg of the carrier gas in a range of the upper
limit value Tu to the lower limit value Td; and
the control means, upon the supply amount C2 of the pulverized coal
of low-grade coal not being the prescribed amount Ct, controls the supply
amount adjustment means for low-grade coal so as to increase the supply
amount C2 of the pulverized coal of low-grade coal, and controls the supply
amount adjustment means for high-grade coal so as to decrease the supply
amount C1 of the pulverized coal of high-grade coal.
5 5. The blast furnace installation according to claim 1, wherein
the pyrolysis means pyrolyzes the low-grade coal at from 400 to
600°C.
6. The blast furnace installation according to claim 1, wherein
10 the high-grade coal is anthracite coal or bituminous coal, and
the low-grade coal is sub-bituminous coal or lignite.
7. The blast furnace installation according to claim 1, wherein
the inert gas is at least one among nitrogen gas, off-gas discharged
15 from the blast furnace body, and combustion exhaust gas after the off-gas is
combusted with air.