KR101592955B1 - Method for loading raw material into blast furnace - Google Patents

Abstract

According to the present invention, by making the average layer thickness L _av1 for each turn of the swivel chute determined by the formula 1 smaller than the thickness h of the coke charged in the central portion of the blast furnace shaft, the amount of coke is small, It is possible to provide a method of charging a raw material into a blast furnace that ensures air permeability in the blast furnace and stabilizes blast furnace operation and improves thermal efficiency even when operation is performed. In addition, Equation 1, and L _av1 = V _n / a [(R _n ² -R ² _{n -1)} π], V _n is turning the raw material charged per volume (㎥) in the turning of the n-th, R _n Is the falling radius (m) of the loading material in the n-th turn.

Description

[0001] METHOD FOR LOADING RAW MATERIAL INTO BLAST FURNACE [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of charging a raw material into a blast furnace in which a raw material is charged in a furnace in a turning chute.

Generally, blast furnace, pellet, lump ore and other raw materials for cement and coke are charged in a layer form from a furnace top, and a combustion gas is flowed from a tuyere, . The charged coke and raw materials for the blast furnace, which are charged into the blast furnace, are lowered to the bottom of the furnace, and the ores are reduced and the temperature of the raw materials is raised. The optical material layer is gradually deformed by filling up the gap between the raw materials of the glaze due to the elevated temperature and the load from above, and forms a fusion layer in which the gas resistance hardly flows due to the large ventilation resistance below the shaft portion of the blast furnace.

Conventionally, raw material charging into a blast furnace is alternately charged with raw material for cement and coke. In the furnace, a raw material layer and a coke layer are alternately layered. Further, in the lower part of the blast furnace, there is an optical powder raw material layer in which the ore called a fused bond is soft-fused and has a large air resistance, and a coke slit of relatively low air resistance derived from coke.

The air permeability of the fusing belt greatly affects the air permeability of the whole blast furnace, and the productivity in the blast furnace is controlled. It is also conceivable that the coke slit becomes infinitely thin when the low coke operation is performed because the amount of coke to be used is reduced.

It is known that it is effective to mix coke in the raw material layer of the optical fiber in order to improve the ventilation resistance of the fusing belt, and many studies have been reported to obtain a proper mixing state.

For example, in Patent Document 1, in a bell-less blast furnace, coke is charged into an ore hopper on the downstream side of an ore hopper, coke is stacked on the ore on a conveyor, Ore and coke are charged into the blast furnace through the swivel chute.

In Patent Document 2, the ore and coke are separately stored in the bunker of the Lokun, and the coke and the ore are mixedly charged at the same time, whereby the batch for the normal charging of the coke, the batch for the central charging of the coke, Are performed at the same time.

In Patent Document 3, in order to prevent the destabilization of the fusing bar shape in the blast furnace operation and the lowering of the gas utilization rate in the vicinity of the central portion and to improve the safety operation and the thermal efficiency, the method of charging the raw materials in the blast furnace So that the entire ore and the entire coke are completely mixed and then charged into the furnace.

Japanese Patent Application Laid-Open No. 3-211210 Japanese Patent Application Laid-Open No. 2004-107794 Japanese Patent Publication No. 59-10402

However, it is known that it is effective to mix coke in the ore layer as in the technique described in Patent Document 3 described above in order to improve the ventilation resistance of the fusing belt.

However, since the representative coke described in Patent Document 3 has an average particle size of about 40 to 50 mm and an average particle size of ore of about 15 mm, the particle diameters of both coke are greatly different from each other, The porosity is drastically lowered and the air permeability in the furnace is deteriorated to cause troubles such as blowout of the gas and poor descent of the raw material.

Further, even if the ore and the coke are ejected from two bunkers at the same time and mixedly charged, the coke of the larger diameter rolls farther due to the inclination of the entry surface, so that the coke is easily separated.

In order to avoid such a problem, a method of forming only a layer of coke in the cylinder axis portion can be considered. According to this method, since the passage of the gas by the coke oven layer is secured in the shaft axial part, the air permeability can be improved. In addition, it is known that, when the ore and the coke are simultaneously blown out and mixedly charged, reverse tilting charging the loading raw material from the center is effective for the above-mentioned trouble avoidance.

However, in the case where the distance between the raw materials to be charged in the blast furnace is small, or the amount of the charging raw material per one turn is too large, the mountains of the raw materials charged at the time of turning are over the mountains of the raw materials charged at the next turning . In this case, the raw material flows into the center portion of the blast furnace, and the mixed coke is separated, resulting in deterioration of the mixing rate control property and lowering of the coke mixing ratio. In addition, in the case of simultaneous outflow mixing charging in which reverse charging is carried out, in particular, in the case where the interval of charging the raw material is narrow, the charging raw material flows into the center side over the acid of the raw material sprayed immediately before and the mixed coke is separated, And the problems such as deterioration of the properties and lowering of the coke mixing ratio are caused.

The present invention has been developed in view of the above phenomenon, and it is possible to achieve the stabilization of the blast furnace operation and the improvement of the thermal efficiency by securing the mixing property in the mixed layer even when the interval between the raw materials is narrow, It is possible to control the amount of raw material to be charged per turn or the interval of charging per one turn so as to prevent the acid of the previously charged raw material from flowing into the center side beyond the rush of the raw material charging raw material, It is an object of the present invention to provide a method of charging a raw material into a blast furnace which is capable of achieving stabilization of blast furnace operation and improvement of reaction efficiency by securing the mixing property in the mixed layer.

That is, the structure of the present invention is as follows.

1. In charge of charging raw material into blast furnace, it is divided into two or more batches of coke charging and two or more batches of ore charging, and charging is carried out by using turning sleeves. In doing so,

_Wherein the average layer thickness L _av1 for each turning of the swivel chute obtained by the following formula 1 is smaller than the thickness h of the coke charged in the axial center of the blast furnace.

L _av ? ₁ = V _n / [(R _n ² -R _n-1 ² )?] One

Herein, V _{n is the} volume (m 3) of the charged raw material per turn (the charging density per turn (t) / (apparent density of the coke and ore mixed layer (t / m 3) in the n th turn) ]

R _n : Falling radius (m) of loading material in n turns

2. In multi-batch charging where raw material charge to blast furnace is divided into two or more batches of coke charging and two or more batches of ore charging and charging by turning sleeves, the coke charging and the ore charging are simultaneously carried out At that time,

the average layer thickness of the n-th turn of the swivel chute determined by the following formula (2): L _av2 (n) and the average layer thickness of the (n + 1) th turn obtained by the following equation 3: L _av2 (n + 1) satisfies the following formula (4).

L _av2 (n) = V _n / [(R _n ² -R _{n -1} ² )?] 2

L _av2 (n + 1) = V _{n +1} / [(R _{n +1} ² -R _n ² )?] 3

Here, V _n : the volume (m 3) of the charging material per turn at the turn of the n-th turn,

R _n-1 : Falling radius (m) of the loading material in the (n-1)

R _n : Falling radius (m) of loading material in n turns

V _{n + 1} : Volume of loaded raw material per turn (m 3) in turning at n +

R _{n +1} : Falling radius (m) of the loading material in the (n + 1)

L _av2 (n + 1) < L _av2 (n) ... 4

According to the present invention, when the raw material and the coke are charged into the blast furnace, the charging raw material is sprayed at a predetermined position and the mixed coke is not separated. Therefore, the air permeability at the lower portion of the furnace is remarkably improved, It is possible to perform stable blast furnace operation even in a situation where the interval between the raw materials is narrow, or when the reverse blind loading is applied when the coke oven simultaneous blending and mixing blades are applied.

Fig. 1 is a schematic view showing a method of charging a raw material into a blast furnace.
Fig. 2 (a) is a schematic view showing the conventional state, and Fig. 2 (b) is a schematic view showing the state of loading each raw material according to the present invention.
Fig. 3 (a) is a schematic view showing the state of the prior art, and Fig. 3 (b) is a schematic view showing the state of each of different raw materials according to the present invention.
Fig. 4 is a schematic view showing a state of charging a raw material in a blast furnace according to the present invention and a state of charging a raw material in a usual blast furnace.
Fig. 5 is a schematic view showing a state of charging different raw materials into a blast furnace according to the present invention and a state of charging raw materials in a normal blast furnace.
FIG. 6 is an explanatory diagram showing a reduction state, a ventilation / electric heating state, and a molten carburization state in the upper, middle, and lower parts of the blast furnace according to the present invention in comparison with the raw material charging state in the blast furnace and the raw material charging state in the normal blast furnace.
Fig. 7 is a schematic configuration diagram showing an experimental apparatus for measuring the high-temperature property of the raw material of the goblets.

(Mode for carrying out the invention)

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, representative embodiments of the present invention will be described with reference to the drawings.

A specific charging method for charging raw material and coke into the blast furnace will be described with reference to Fig.

In the following description, it is assumed that the rook bunkers 12a are stored with coke only, and the rook bunkers 12b and 12c are stored with raw pomegranate.

In the drawing, reference numeral 10 denotes a blast furnace, 12a to 12c are log bunkers, 13 is a flow rate adjusting gate, 14 is a collecting hopper, 15 is a Belisys charging device, and 16 is a turning suit. Further, &thetas; is an angle with respect to the vertical direction of the swivel chute.

When the center coke layer is formed at the center of the blast furnace as the raw material charging order from the lozenge bunker, the raw material charging destination of the turning chute 16 is the center side of the blast furnace, and the rook bunkers 12a, A center coke layer is formed at the center of the blast furnace. Further, a peripheral coke layer may be formed in the inner portion of the furnace wall.

That is, the flow regulating gates 13 of the locating bunkers 12b and 12c are closed and the flow regulating gates 13 of the locating bunker 12a are closed only in the state where the material charging point of the turn chute 16 is directed toward the center side of the blast furnace. And only the coke stored in the lozenge bunker 12a is supplied to the orbiting chute 16 to form a center coke layer at the center of the blast furnace.

Next, the charging order is carried out simultaneously from the rook bunkers 12a, 12b or 12c by coke charging and ore charging. However, the charging order at that time is sequentially moved from a position close to the center axis of the blast furnace, That is, in the direction in which? Is large, and finally, the top side of the oblique side wall is charged.

Here, in the present invention, it is important to make the average layer thickness L _av1 for each turn of the swivel chute obtained by the following formula 1 smaller than the thickness h of the center coke charged in the axial center of the blast furnace.

L _av ? ₁ = V _n / [(R _n ² -R _n-1 ² )?] One

Here, V _{n is} the charge amount per revolution (t) / (apparent density of the coke and ore mixed layer (t / m 3) in the n th revolution)

R _n : Falling radius (m) of loading material in n turns

[L _av1 <h]

In the case where the raw material or the coke is segregated at the transportation facilities up to the locating bunker, only the raw raw material or the coke is charged, and the coke or the coke charged from the other locating bunkers 12a, 12b and 12c in the collecting hopper 14 The proportion of the raw material or the coke of the raw material is increased and the mixing ratio of the mixed raw material of the raw material and the coke formed by the turning chute 16 becomes uneven.

Therefore, in the present invention, as shown in Fig. 2, the unevenness of the mixed layer is solved by making L _av1 obtained by the formula 1 smaller than the thickness: h of the center coke charged in the central portion of the blast furnace shaft. As a result, The amount of air in the blast furnace can be stably secured even when the volume of the blast furnace is small or the coal blowing operation is carried out.

It is preferable that L _av1 is in the range of about 0.7 to 0.95 times h.

The loading raw material flows into the center side over the acid of the raw material immediately before sprayed and the mixed coke is separated to prevent the deterioration of the mixing rate control property and the decrease of the coke mixing ratio.

In the present invention, it is important to satisfy the relation of L _av1 &lt; h, but specific values include L _av1 of about _0.90 to 1.35 (m) and h of about 1.20 to 1.50 (m) desirable.

That is, in the present invention, the formation of the mixed layer 12e is carried out in such a manner that the average layer thickness L _av1 for each turn of the turning chute determined by the above-mentioned formula 1, h. &lt; / RTI &gt;

In the present invention, when n is an arbitrary natural number, the average layer thickness L _av2 (n) of the n-th turn of the swivel chute obtained by the following formula 2 and the n + 1 line It is important that the average layer thickness _Lav2 (n + 1) of the second time satisfies the following expression (4). Also, R _{n -1} is 0 when n = 1. In the case of forming the center coke, L _av2 (1) = h can be obtained by _letting the height of the center coke be h. Of course, it is also possible to obtain L _av2 (1) by forming the first line regardless of the height of the center coke to obtain R _{n -1} and 0 when n = 1.

L _av2 (n) = V _n / [(R _n ² -R _{n -1} ² )?] 2

L _av2 (n + 1) = V _{n +1} / [(R _{n +1} ² -R _n ² )?] 3

Here, V _n : the volume (m 3) of the charging material per turn at the turn of the n-th turn,

R _{n -1} : Falling radius (m) of the loading material in the (n-1)

R _n : Falling radius (m) of loading material in n turns

V _{n + 1} : Volume of loaded raw material per turn (m 3) in turning at n +

R _{n +1} : Falling radius (m) of the loading material in the (n + 1)

L _av2 (n + 1) &lt; L _av2 (n) ... 4

[L _av2 (n + 1) &lt; L _av2 (n)]

The coke and the raw material of the goblet to be simultaneously discharged from the locating bunkers 12a, 12b or 12c join together in the collecting hopper 14 and are charged through the charging chute. In this case, when the height of the acid of the raw material charged in the ring shape at the n + 1 th line is higher than the acid of the raw material charged in the ring shape at the charging n-th charging station, There is a possibility that the liquid can flow into the liquid. In this case, since the raw material of the (n + 1) th raw material is separated from the coke during the slope flow, the coke mixing ratio is lowered and the effect of improving the air permeability can not be sufficiently exhibited.

Therefore, in the present invention, as shown in Fig. 3, the average layer thickness L _av2 (n) of the n-th turn obtained by the formula 2 is larger than the average layer thickness L _av2 (n + 1) of the The unevenness of the mixed layer is solved and consequently the air permeability in the blast furnace can be stably secured even when the amount of coke is small or the operation of massive blowing of pulverized coal is carried out.

The ratio (L _av2 (n + 1) / L _av2 (n)) of L _av2 (n) and L _av2 (n + 1) is preferably in the range of about 0.5 to 0.9. When the above ratio is 0.9 or more, there is a high possibility that the raw material charged in the (n + 1) -th line is flown into the center side over the acid of the raw material charged in the n-th cycle. When the ratio is 0.5 or less, This is because control of the raw material deposition shape becomes difficult.

In the present invention, it is important to satisfy the relationship of the above-mentioned formula (4). However, specific values include V _{n of} about 2 to 7 m 3, R ₁ of about ₁ to 2 m, m), respectively.

The center coke layer and the mixed layer 12e are successively formed in the blast furnace 10 from the bottom to the top.

According to these methods, a coke layer and a layer composed of the simultaneous blowing mixed layer 12e are successively laminated, so that a coke layer having a small ventilation resistance is formed in the shaft portion and furnace wall portion in the blast furnace 10 from the bottom of the furnace toward the top of the furnace It is possible not only to form the mixed layer 12e in which the coke and the raw material mixture are completely mixed therebetween even in a situation where the interval between the raw materials is narrow, but also to suppress the air permeability degradation due to the lowering of the porosity due to coke mixing . Further, since the mixed layer 12e in which the coke and the raw material of the pumice are completely mixed can be formed between the coke layers, the effect of improving the air permeability at the bottom of the blast furnace can be maximized.

Therefore, as shown in the right half of FIG. 4 or 5, by introducing hot gas mainly composed of CO from the blowing pipe 21 of the tweeter formed in the basin of the lower part of the blast furnace 10 , A gas flow rising through the coke layer is formed and a gas flow rising through the mixture layer is formed. The coke is burned by the hot gas flowing from the blowing pipe 21 to reduce and dissolve the raw material of the optical powder.

The flow of gas in the blast furnace at this time is shown in Fig. Hot air is blown from the blowing pipe 21 provided at the lower part of the blast furnace 10 through the twister to burn coke or pulverized coal near the twister to generate high temperature CO ₂ gas. The CO ₂ gas reacts with the coke in the lower part of the blast furnace to become CO, thereby reducing and dissolving the raw material of the pomegranate.

As a result, the raw gravel material in the lower part of the blast furnace 10 is melted, and the coke and raw material raw materials charged into the blast furnace 10 are lowered from the raw material to the lower part of the furnace, Temperature rise occurs.

For this reason, a fused band softened by the raw material of the fungus is formed on the upper side of the molten layer, and the fungus raw material is reduced on the upper side of the fused band.

At this time, as shown in the right part of FIG. 6, in the lower part of the blast furnace 10, the raw material of the raw fungus and the coke are completely mixed in the mixed layer 12e, and the coke enters the raw materials of the raw fungi, And since the high temperature gas passes directly between the raw materials of the goblets, there is no delay in heat transfer and the heat transfer characteristics can be improved.

Further, in the lower portion of the fusing belt of the blast furnace 10, the contact area between the raw material of the gypsum and the high temperature gas is enlarged, and carburization can be promoted. In addition, the air permeability and the heat transfer property can be improved in the fusing belt. Further, since the raw material and the coke are arranged close to each other in the upper part of the blast furnace 10 as well, the interaction between the reduction reaction of the raw material of the raw material and the gasification reaction (carbon solution loss reaction) Good reduction is performed without causing a reduction delay by the ring reaction.

At this time, the reduction reaction is represented by FeO + CO = Fe + CO ₂ .

Further, the gasification reaction is represented by C + CO ₂ = 2CO.

On the other hand, in the conventional example in which the above-described ores and coke are layered, as shown in the left half of FIG. 4 or 5, the ore and coke are charged alternately in the blast furnace, Shape. In this case, as shown in the left half of FIG. 6, when the hot gas of the CO subject is introduced from the blower 21 of the tweeter, the ventilation is limited by the reduction of the coke slit and the pressure loss is increased , There is a problem that the contact area of the ore with the high-temperature gas becomes small and carburization is limited.

On the upper side of the fusing belt, a coke slit is formed, and heat is conducted to the ore mainly through the coke slit, so that heat transfer is delayed and heat transfer is insufficient. In addition, since the coke oven layer having a good air permeability and the ore layer having poor air permeability are laminated on the upper part of the blast furnace 10, not only the rate of temperature rise is lowered but only the reduction reaction is performed, Therefore, there arises a problem that a reduction delay occurs.

However, in the present invention, as described above, since the charging layer formed of the coke layer and the mixed layer 12e in which the coke and the raw material of the pumice are thoroughly mixed is laminated, the coke slit is not formed in the mixed layer, And it is possible to secure a good heat conduction and to improve the ventilation in a stable manner, and thus it is possible to advantageously solve the above-mentioned conventional problems.

In the past, the amount of coke (kg), i.e., the coke ratio, required for producing 1 ton of hot wire was about 320 to 350 kg / t. However, when the raw material is charged according to the present invention, the coke ratio is 270 to 320 kg / t. &lt; / RTI &gt;

Example

[Example 1]

In order to demonstrate the effect of the present invention, the change of the ventilation resistance was examined by simulating the raw material reduction and the temperature raising process in the blast furnace by using the experimental apparatus shown in Fig.

In this experimental apparatus, a rostrum tube 32 is arranged on the inner peripheral surface of a cylinder-like roving body 31, and a cylindrical heating heater 33 is arranged outside the rostrum tube 32. A graphite crucible 35 is disposed on the upper side of a cylindrical body 34 made of a refractory material and a charging raw material 36 is charged in the crucible 35. In this crucible 35, The loading material 36 is loaded with the load from the top by a load load device 38 connected via a punch rod 37 so as to be in the same degree as the fusing layer under the blast furnace. On the bottom of the cylindrical body 34, a dropping water sampling device 39 is formed.

The gas adjusted by the gas mixing device 40 is fed to the crucible 35 via the cylindrical body 34 at the lower part thereof. Thereafter, the gas that has passed through the charging raw material 36 in the crucible 35 is analyzed by the gas analyzer 41. The heater 33 for heating is provided with a thermocouple 42 for controlling the heating temperature and by controlling the heater 33 for heating with a control device (not shown) while measuring the temperature at the thermocouple 42, 35) is heated to 1200 to 1500 占 폚.

Here, the following materials were used as the charging raw material 36 charged into the crucible 35.

(Comparative Example 1-1) in which the coke was not completely mixed with the ore layer and the various charging conditions, the average layer thickness L _av1 and the thickness of the center coke: h shown in Table 1, the pulverized coal ratio was 180 _kg / t of high-grade pulverized coal. Table 1 shows the productivity obtained by dividing the output (t / d) of the blast furnace per day by the internal volume (m 3).

In addition, the charging amount of the charging raw material per turn: V _n , the initial falling radius of the charging raw material: R _1, and the radius increase amount per accumulation of the charging raw material: ΔR are as shown in Table 1. Also, R _n -R _{n -1} =? R (n is an arbitrary natural number).

The results of operation in each case are also shown in Table 1.

In Table 1, the coke ratio and pulverized coal ratio are the amount of coke and the amount of pulverized coal (kg) used in producing the molten iron 1t.

The reduction ratio is the sum of the coke ratio and the pulverized coal ratio.

The gas utilization ratio is the ratio of the concentration of CO _{2 to the} concentration of CO in the crude oil, and is calculated by the following equation.

Gas utilization rate = CO ₂ / (CO ₂ + CO) × 100

Here, CO ₂ is the concentration of rosin CO ₂ [%]

CO is the concentration of roast CO [%]

DELTA P / V is an index obtained by indexing the aeration resistance in the blast furnace, and is calculated by the following equation.

? P / V = (BP-TP) / BGV

In this case, BP represents the blowing pressure [Pa]

TP is the relative pressure [Pa]

BGV is Bosch gas volume [m3 (standard condition) / min]

As is apparent from Table 1, the coke ratio of Comparative Example 1-1 was 342 kg / t, but L _av1 was in the range of about _0.7 to 0.95 times of h, L _av1 was about _0.90 to 1.35 (m) The coke ratio of the inventive example 1-1 is set to 312 kg / t, and the coke ratio of the inventive example 1-2 is set to 300 kg / t (t). In the case where the raw material is charged according to the present invention, It is possible to reduce it to a degree of

It has been proved that the ventilation resistance can be reduced even in the case of the low reducing cost by the low coke ratio.

Further, in the above embodiment, the revolution per jangipryang: V _n and turning the party radius increase in the drop radius of the charged raw materials: if, but fixed for each embodiment the ΔR example, satisfy the relationship of L _av1 <h, V per revolution _n or The effect of the present invention can be obtained without any problem even if the? R is changed.

In the above embodiment, the description has been given of the case where the central coke oven layer and the mixed layer are formed by the tilting of the turning chute and the opening and closing control of the flow rate adjusting gate of the loam bunker. However, the present invention is not limited to this, A coke-dedicated chute for injecting the coke directly into the circulating chute may be disposed at a position not interfering with the turning chute, and the central coke layer may be formed by charging the coke directly into the shaft portion of the blast furnace by the coke-dedicated chute. Accordingly, when L _av1 is in the range of about 0.7 to 0.95 times of h, L _av1 is in the range of about _0.90 to 1.35 (m), and h is in the range of about 1.20 to 1.50 (m), even in the case of the low- , It has been demonstrated that the ventilation resistance can be reduced.

[Example 2]

In addition, the raw material charging test was carried out in the blast furnace having the internal capacity of 4000 psi and the operating conditions were compared. In this blast furnace, as shown in Fig. 1, there are three independent bunkers on the upper part of the blast furnace, and the coke or raw material for pumice is charged into each of them. In the case of usual charging, the coke 2 batch is charged for each charge, and the 2 batches of the raw material for coke are charged. At the mixing charge (120 kg / t), after the coke 1 batch charge, Coke was charged into the center portion in the first half of the furnace to form a center coke layer. Thereafter, the raw material of optic puddle was simultaneously cut out from the other bunker, and the raw material was charged by reversely charging the raw material to form a coke mixed layer.

The test results according to the above procedure are shown in Table 2.

In Table 2, the coke ratio and pulverized coal ratio are the amount of coke used and the amount of pulverized coal (kg) used in producing the molten iron 1t.

The reduction ratio is the sum of the coke ratio and the pulverized coal ratio.

The gas utilization ratio is the ratio of the concentration of CO _{2 to the} concentration of CO in the crude oil, and is calculated by the following equation.

Gas utilization rate = CO ₂ / (CO ₂ + CO) × 100

Here, CO ₂ is the concentration of rosin CO ₂ [%]

CO is the concentration of roast CO [%]

DELTA P / V is an index obtained by indexing the aeration resistance in the blast furnace, and is calculated by the following equation.

? P / V = (BP-TP) / BGV

In this case, BP represents the blowing pressure [Pa]

TP is the relative pressure [Pa]

BGV is the amount of Boshu gas [m3 (standard state) / min]

As is apparent from Table 2, Inventive Examples 2-1 and 2-2 exhibited a? P / V lower than those of Comparative Examples 2-1 and 2-2 having high coke ratios. Also, the same ΔP / V was obtained as in Comparative Example 2-2, in which the coke ratio was 310 kg / t and the lower coke ratio was 350 kg / t even in the case of Inventive Example 2-3.

From the above results, it was proved that the ventilation resistance can be reduced even in the case of a low reducing material ratio with a low coke ratio.

In the above embodiment, the amount of charge per turn V _n and the radial increase amount per unit turn of the dropping radius of the loading material: R are fixed for each of the embodiments, but if the relationship L _av2 (n + 1) &lt; L _av2 , The effect of the present invention can be obtained without any problem even if V _n or? R for each turn is appropriately changed.

10: blast furnace
12a to 12c: rosin bunkers
13: Flow regulating gate
14: Set hopper
15: Bellis type charging device
16: Turning suit
31:
32: Corresponding to
33: Heating heater
34: Cylindrical body
35: Graphite crucible
36: Raw materials
37: Punch bar
38: Load Load Device
39: Dropping water sampling device
40: gas mixing device
41: Gas analyzer
42: Thermocouple

Claims (2)

In charge of charging of raw material to blast furnace, it is divided into two or more batches of coke charging and ore charging and more than two batches of ore charging and charging by turning sleeves. When performing by simultaneous extraction,
wherein the average layer thickness L _av1 for each turning of the turning chute obtained by the following formula 1 is set smaller than the thickness h of the coke charged into the center of the shaft of the blast furnace, Charging method.
L _av ? ₁ = V _n / [(R _n ² -R _n-1 ² )?] One
Here, V _{n is} the charge amount per revolution (t) / (apparent density (t / m 3) of the mixed layer of coke and ore)
R _n : Falling radius (m) of loading material in n turns
R ₀ = 0 In the multi-batch charging in which the raw material charge in the blast furnace is divided into two or more batches of coke charging and two or more batches of ore charging and charging by turning sleeves, when the charging of the coke and the charging of the ore are carried out simultaneously ,
the average layer thickness of the n-th turn of the swivel chute determined by the following formula (2): L _av2 (n) and the average layer thickness of the (n + 1) th turn obtained by the following equation 3: L _av2 (n + 1) satisfies the following formula (4).
_{L av2 (n) = V n} / [(R n 2 -R n-1 2) π] ... 2
_{L av2 (n + 1) =} V n + 1 / [(R n + 1 2 -R n 2) π] ... 3
Here, V _n : the volume (m 3) of the charging material per turn at the turn of the n-th turn,
R _n-1 : Falling radius (m) of the loading material in the (n-1)
R _n : Falling radius (m) of loading material in n turns
V _{n + 1} : Volume of charged material (m 3) per turn during turning in the (n + 1)
R _{n + 1} : Falling radius (m) of the loading material in the (n + 1)
R ₀ = 0
L _av2 (n + 1) &lt; L _av2 (n) ... 4

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