JPH0627284B2 - Blast furnace operation method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for operating a blast furnace, and more particularly to a method for controlling a charge distribution when pulverized coal is injected.

(Prior Art) The main control means of the blast furnace are air flow control and charge distribution control.

Among these, the air flow control factors include air flow rate, air flow temperature,
The blast humidity, the oxygen enrichment rate, the tuyere wind speed, and the amount of auxiliary fuel injected are weights. Here, heavy oil, which is a liquid fuel, tar, pulverized coal, which is a solid fuel, and natural gas, which is a gas fuel, and coke oven gas are generally used as auxiliary fuels. Has been discontinued and all coke operation has been changed to use no auxiliary fuel. However, in order to reduce the coke ratio and to prevent lower furnace inertness in all coke operation, that is, to avoid a temperature lowering phenomenon near the lower furnace wall, the number of blast furnaces performing pulverized coal blowing operation is increasing recently. In Western countries, many blast furnaces operate by blowing natural gas.

On the other hand, the factors controlling the distribution of the charge are as follows:
It is important to control the distribution of (ore / coke) weight ratio (hereinafter abbreviated as O / C), the distribution of particle sizes of ore and coke, and the distribution of use ratio of ore or coke by brand. Here, the charge distribution control is performed by adjusting the tilt angle of the movable armor in the bell-type blast furnace.
Further, in the bellless type blast furnace, it is performed by adjusting the tilt angle and the number of turns of the turning chute.

By the way, the biggest problem of the charge distribution control is to elucidate the optimum charge distribution and to establish a concrete control method for obtaining the optimum charge distribution.

However, the conventional technique has a big problem that the concept of the optimum charge distribution is unclear and an appropriate charge distribution control technique cannot be established.

In other words, the optimum charge distribution is supposed to differ depending on the operating conditions of the blast furnace, such as the amount of tapping, the level of the fuel ratio, and the use of auxiliary fuel. It is generally thought that there is an optimal charge distribution that can be universally applied regardless of whether or not fuel is injected. The distribution was such that the O / C was increased over a wide range in the radial direction inside the furnace except for the vicinity of the part (iron and steel, 67 (1981), P. 1574).

By the way, the optimum charge distribution in the above document is the utilization rate of CO gas in the radial direction of the furnace top ηco (ηco = CO ₂ / CO ₂ /
_{(CO 2 + CO), CO} 2, CO: furnace top CO ₂ in the gas,
It is obtained empirically and statistically using CO volume%) or gas temperature distribution as an index. Further, in the conventional technique, ηco or the gas temperature is basically uniform in the furnace radial direction to secure a strong gas flow in the center of the furnace and the peripheral portion of the furnace wall (decrease of ηco or gas temperature This was a method of determining the distribution of the charge by trial and error (Iron and Steel, 68 (1982), P.2319).

In addition, based on a concept similar to the above, JP-A-59-6
In Japanese Patent No. 307 publication, when the auxiliary fuel is blown,
/ C is proposed to be 4 or more.

As described above, in the conventional charge distribution control technique, the charging method is changed by trial and error so that the target distribution of ηco can be obtained while operating.

Next, the second problem regarding the distribution of the charge is that during the operation of all coke, the phenomenon that the temperature near the furnace wall in the lower part of the furnace lowers, that is, the inertness phenomenon in the lower part of the furnace is likely to occur. The elucidation of the cause of the generation of is an important issue.

In the all coke operation, ideally, as shown in the above-mentioned document (Iron and Steel, 67 (1981), P. 1574), the O / C in the furnace radial direction is made uniform, and
Although it is desirable to make C as large as possible, in reality, O / n in the vicinity of the furnace wall (a region of about 1 m from the furnace wall)
C is reduced, and the ratio of the O / C to the average O / C at the time of charging, that is, the relative O / C of the furnace wall is economically set in the range of 0.6-0.9.

Next, regarding the influence of pulverized coal injection on the operation of the blast furnace, the inventors of the present invention, in Japanese Patent Publication No. 61-2002, in the combustion zone (hereinafter referred to as raceway) formed in front of the tuyere in the blast furnace. A method of measuring the gas composition distribution in the furnace radial direction and thermodynamically estimating the temperature distribution of the combustion gas in the furnace radial direction based on the gas composition distribution is proposed, and by the estimation method, during pulverized coal injection operation It was found that the combustion focus, that is, the position of the maximum combustion temperature, moves from the center side of the furnace to the tuyere side compared to the time of all-coke operation.By the time the temperature distribution and the charge distribution at the furnace top are related, Has not arrived.

(Problems to be Solved by the Invention) An object of the present invention is to search for an optimum charge distribution by trial and error in controlling the charge distribution, which is an important control factor of a blast furnace. A method to revise the technical problems and to a priori estimate an appropriate O / C in the vicinity of the furnace wall, which greatly affects blast furnace operation, from the temperature distribution in the tuyere level furnace radial direction when pulverized coal is injected And to provide a method for elucidating the cause of furnace bottom inertness during all coke operation.

(Means for Solving the Problem) The present invention is an epoch-making method of controlling the distribution of charges for stabilizing blast furnace operation during pulverized coal injection and improving blast furnace operation results. In the pulverized coal injection operation in, the weight ratio of (ore / coke) in the vicinity of the furnace wall within 1 m from the furnace wall at the setting position of the lump zone was calculated, and the weight ratio and the average (ore / coke) at the time of charging were calculated. ) Weight ratio is
Adjusting the (ore / coke) weight ratio in the vicinity of the furnace wall by adjusting the tilt angle of the movable armor or the turning chute or the number of turns of the turning chute so as to match γ calculated by equation (1). It is a characteristic method of operating the blast furnace.

Where γ ^* : relative (ore / coke) weight ratio of the furnace wall during all coke operation, I _fp : horizontal distance between pulverized coal blowing position and tuyere tip,
Meltability index of the furnace wall, which is determined by the particle size of pulverized coal and the amount of pulverized coal injected, Melting capacity index of furnace wall during all coke operation.

Hereinafter, features of the present invention will be described in detail with reference to the drawings.

FIG. 2 shows the outline of the experimental apparatus used in the method of the present invention. In FIG. 2, the main body of the apparatus is a raceway furnace 6, the inner diameter of the furnace is 2 m, the furnace height is 5 m, and the internal volume is 10 m.
It is ³ . The inner diameter of the tuyere 1 is 70 mm, and the scale ratio with the actual blast furnace is about 1/2. In the raceway furnace, the hot air for blowing is adjusted to a predetermined oxygen concentration by enriching oxygen in the combustion exhaust gas generated by burning heavy oil with air in the hot air generator 10 and through the blow pipe 7 and the tuyere 1. Blow into. The pulverized coal 9 is blown from the tip of a blow burner 8 provided through the blow pipe 7 or the tuyere 1.

The combustion experiment of pulverized coal was carried out by charging about 5 tons of coke 12 in advance from the furnace top manhole 3 of the raceway furnace 6 and filling the coke. During the experiment, a horizontal sonde 11 installed at the tuyere level was used to measure the gas composition (CO ₂ , CO, H ₂ , O ₂ ) distribution in the tuyere level furnace radial direction, and the gas composition distribution was used to No. Sho 61-12002
The temperature distribution of the combustion gas in the radial direction of the tuyere level furnace was estimated based on the method disclosed in the publication.

Furthermore, the combustion exhaust gas and dust generated in the raceway furnace were sampled from the sampling hole 4 provided in the furnace top duct, and the method proposed by the present inventors in Japanese Patent Application No. 62-156553, that is, dust The combustion efficiency of pulverized coal was calculated on the basis of the AI ₂ O ₂ balance method, and the presence state of char in the dust was measured by microscopic observation.

FIG. 3 is an enlarged view of the main parts of the blow pipe 7 and tuyere 1 of FIG. 2, and shows a method of blowing pulverized coal.

In the experiment of the present invention, when changing the horizontal distance L (m) between the pulverized coal blowing position (the tip of the blowing burner 8) and the tuyere tip, when L> 0.2 m, FIG. (A)
The burner 8 was inserted through the blow pipe 7 as described above, and when L ≦ 0.2 m, the burner 8 was inserted through the tuyere 1 as shown in FIG.

The experimental conditions of the raceway furnace are shown below.

(1) Chemical composition of pulverized coal (industrial analysis value) Volatile content 32% by weight Fixed carbon 57% by weight Ash content 10% by weight (elemental analysis value) Carbon 74% by weight Hydrogen 5% by weight Carbon 9% by weight (2) Blast condition Blast Temperature 1100-1300 ° C Airflow 1100 Nm ³ / h Airflow pressure 2-4 Gravity Kg / cm ² (gauge pressure) Oxygen concentration 21-25% by volume Theoretical combustion temperature 2170 ° C (3) Amount of pulverized coal blown Rpc (Kg / t) 0, 30, 60, 90, 120, 150, 180 Kg / t (4) Distance L (m) 0.03, 0.06, 0.1, 0.2, 0.3, 0.4, between the injection position of pulverized coal and the tuyere tip 0.5 m (5) Pulverized coal particle diameter dp (mm) 0.05, 0.1, 0.2, 0.3, 0.4, 0.5 mm The above experimental conditions are in the range assumed as the operating conditions for blowing pulverized coal into the blast furnace. Yes, and the combustion efficiency of pulverized coal is almost 10 under all pulverized coal injection conditions.
It was confirmed to be 0%.

Here, the blowing amount Rpc (Kg / t (pig iron)) of the pulverized coal is 1100 Nm of the required air flow of the blast furnace for producing 1 ton of pig iron.
It is calculated from the numerical value of the pulverized coal injection amount (Kg / h) in the experiment by assuming that it is ³ / t.

Experiments were carried out by combining the above pulverized coal injection methods, and the gas composition (CO ₂ , CO, H
₂ , O ₂ ) distribution was measured and the temperature distribution of the combustion gas in the tuyere level furnace radial direction was estimated using the gas composition distribution based on the method disclosed in Japanese Patent Publication No. 61-22002. . An example of the estimation result is shown in FIGS. 4 (a) and (b) and FIGS. 5 (a) and (b).

FIGS. 4 (a) and 4 (b) are the results under the condition that pulverized coal is not blown, that is, the condition corresponding to the all coke operation, and FIG. 4 (a) is the gas composition distribution, FIG. b) is the temperature distribution.

The position of the raceway depth D _R is shown by the ∇ mark on the horizontal axis in the figure, but under the conditions of this experiment, D _R = 0.6 m. By the way, since the scale ratio of this experimental apparatus is about 1/2, the actual raceway depth D _R of the blast furnace corresponds to about 1.2 m. The raceway depth D _R was determined by the inventors of the present invention as disclosed in JP-A-62-62.
It is a value estimated from the blowing condition based on the method disclosed in Japanese Patent Publication No. 1808.

FIGS. 5 (a) and 5 (b) show the results under the conditions corresponding to the operation of large-scale injection of pulverized coal. That is, the injection amount of pulverized coal Rpc
= 170 Kg / t, blowing position L = 0.1 m, particle size of pulverized coal
dp = 0.3 mm.

As is clear from comparing FIG. 4 and FIG. 5, the temperature near the tip of the tuyere is completely different between the all-coke experiment and the pulverized coal injection experiment. Comparing the temperature at the 0.2m position,
The temperature during pulverized coal injection is about 1000 ° C. higher than the temperature during all coke. That is, it is estimated that the gas melting ability in the vicinity of the tip of the tuyere is higher when the pulverized coal is injected than when it is all coke.

Therefore, in order to calculate the melting ability index of gas in the falling region of the charge near the tip of the tuyere in the raceway, an estimation formula for the gas flow velocity distribution in the raceway is derived, and the above equation is derived from the estimation formula. The falling area of the charge was estimated and the average temperature of the gas in that area was calculated.

FIG. 6 is a schematic diagram for calculating the gas flow velocity distribution in the raceway. Here, for the purpose of clarifying the region through which the main flow of gas in the raceway passes, the conditions under which the volume of the gas does not increase or decrease due to the reaction at the isothermal and isobaric pressure were assumed.

Assuming a case in which a cylinder with an inner diameter D _t (m) is hypothesized on the central axis of the tuyere 1 and a jet of blast blows out from the tip of the tuyere into the furnace, the horizontal distance from the tip of the tuyere is x (m) Let u be the velocity of the gas in the furnace radial direction at a position where the radius (vertical distance) from the tuyere axis is r (m).
_Let u be the average velocity of the gas in the cylinder at the position _{r, x} (m / h), x.
_{If x} (m / h), then u _{r, x} and u _x are expressed by Eqs. (2) and (3), respectively (Yosendo published, Smelting and Chemical Engineering Exercise (Strict Edition), (1974) , P. 81).

u _{r, x} / u _{o, x} = [1 + a {r / (x + l)} ² ] ^-2
_{(2) u x = u o} , x / _{[1 + a {D t / (} x + l)} 2/4 ]
(3) However, Where u _{o, x} is the velocity (m / h) of the gas in the furnace radial direction at the position where the horizontal distance from the tuyere tip on the tuyere axis is x (m), and u _o is x = 0, that is, The average velocity of the gas in the cylinder at the tip of the tuyere (tuyere wind velocity) (m / h), l is the distance between the origin of the jet (point O) and the tip of the tuyere (m) a is the following equation (10) Is a parameter given by.

Equation (6) holds from the definition of equation (2).

u∞, x / u _{o, x} = (1 + a · tan ² θ) ^-2 (6) where θ is 1/2 of the divergence angle of the jet, and in Fig. 6 the boundary surface OPQR of the jet and the wing It is the angle formed by the axial surface.

Incidentally, in FIG. 6, the boundary surface OPQR of the jet flow is bent at the point Q, but since it is bent due to the space on the paper surface, OPQR is actually a straight line.

The point P is the intersection of the jet boundary surface and the raceway boundary surface, and the point R is the intersection of the vertical surface at x on the tuyere axis and the jet boundary surface. If the velocity in the direction is u ∞, _x (m / h), then u ∞, _x / u _{o, x} = 0.05 is assumed.

Therefore, it can be considered that the gas hardly flows in the region of the angle of θ or more in FIG. Substituting Eqs. (4) and (5) into Eq. (3) and rearranging yields Eq. (7).

However, Here, assuming equation (9), substituting equations (8) and (9) into equation (7) and rearranging for a yields equation (10).

In _{x = D R, u x /} u o = τ; (τ: constant) (9) By the way, considering that the gas flow velocity at the tip of the raceway is small because there is a considerable amount of powder coke accumulated near the tip of the raceway, setting τ = 0.05 gives equations (10) and (5). Equations (11) and (12) are obtained.

a = 0.00263 (D _R / D _t ) ² (11) l = 0.0256D _R (12) Furthermore, assuming an actual blast furnace, D _R = 1.5 m, D _t =
Substituting equation (11) into equation (6) with 0.14 m, equation (13) is obtained.

θ = 73 °, a = 0.30, l = 0.038m (13) That is, 1/2 of the spread angle of the jet from the tuyere tip is about 7
It is estimated to be 3 °, and it can be considered that there is no gas flow in the upper part of the straight line OP in FIG. 6, that is, in the shaded part.

In other words, in the region below the straight line OP, the inertia of the jet from the tuyere displaces the charge to form the space portion of the raceway, but the area around the raceway immediately above the tuyere is shaded with diagonal lines. It can be explained that the charge flows into the raceway from this area because the inertial force of gas hardly acts on the area.

Now, in Fig. 6, assuming that the charge flows into the raceway from the shaded portion, the gas temperature of the part of the straight line OT, which is the straight line OP projected on the tuyere axis, is the charge (melting layer of ore).
It is important because it relates to the melting ability of Therefore, straight line OT
_Let z (m) be the length of the raceway and _DH (m) be the height of the raceway (straight line PT). Z can be expressed by equation (14).

z = D _H / tan θ (14) Here, assuming that D _H = D _R and substituting the expression (13) into the expression (14), the expression (15) is obtained.

z = 0.30D _R (15) In the method of the present invention, the average gas temperature Ta on the tuyere axis from the tuyere tip to the range of 30% of the raceway depth D _R.
Is calculated from the temperature distribution in the furnace radial direction, and the ratio of the average gas temperature Ta (° C.) to the theoretical combustion temperature Tf (° C.) is calculated by the equation (16), and the melting capacity index I _fp (−) of the furnace wall is calculated. It is defined as

I _fp = Ta / Tf (16) where the theoretical combustion temperature Tf is the thermodynamic temperature under adiabatic conditions when oxygen and water vapor in the blast react with red hot coke and the total amount changes to CO and H _2. Therefore, since the melting point index I _fp of the furnace wall is almost equal to the gas temperature at the tip (peripheral) of the raceway, the melting ability of the combustion gas near the tip of the tuyere and the combustion flowing out from the periphery of the raceway are It is the ratio of the melting ability of the gas.

In FIGS. 4 (b) and 5 (b), the method of calculating the average gas temperature Ta in the range of 0.3D _R from the tuyere tip is a method by figure integration or a numerical value by polynomial approximation of the temperature distribution. Any method of integration may be used.

Next, the melting capacity index I _fp of the furnace wall portion obtained by the equation (16) is related to the melting capacity of the charge, that is, the deposit of ore, which falls within the range of about 1 m from the furnace wall. A supplementary explanation will be given with reference to FIG.

In FIG. 6, the distance between the point T on the tuyere shaft and the tip of the tuyere is 0.4-0.6 m in the case of the actual blast furnace. further,
The tip of the tuyere protrudes 0.4-0.5 m from the furnace wall to the inside of the furnace, so the boundary point P at which the charge flows into the raceway
The horizontal distance between the position and the furnace wall can be considered to be about 1 m. Therefore, when the fusion layer descending 1 m from the furnace wall is not melted and drops directly above the raceway, it is not heated so much by the combustion gas and the inside of the raceway is shaded from the shaded area in FIG. There is a high possibility that it will flow into and will be melted and dropped inside the raceway.

On the other hand, the fusion layer descending from the point P toward the center of the furnace, that is, the region 1 m or more away from the furnace wall, is heated and melted above the raceway by the combustion gas flowing out from the raceway, and the peripheral portion of the raceway is dripped. It is estimated that

By the way, in order to maintain stable blast furnace operation, it is necessary to prevent the unmelted fusion layer from flowing into the raceway. For that purpose, it is important to set the O / C in the vicinity of the furnace wall so as to match the melting capacity index I _fp of the furnace wall.

FIGS. 7 (a), (b), and (c) show the melting capability index I _fp of the furnace wall under the blowing condition of each pulverized coal shown in this experiment, calculated by the above method, Using the particle size dp and the pulverized coal injection position L as parameters, the melting capacity index I of the furnace wall
₄ shows the relationship between _fp and the pulverized coal injection amount R _pc .

FIG. 7 shows the results when the particle diameter dp is 0.1 mm, 0.3 mm, and 0.5 mm, but the influence of dp, L, and Rpc on the melting capacity index I _fp of the furnace wall is large. I understand. Especially,
The influence of the pulverized coal injection amount R _pc is large, and the melting capacity index I _fp of the furnace wall portion under all coke conditions, that is, Is as small as 0.56. In other words, the melting capacity of the gas near the furnace wall at the tuyere level during all coke operation is 56% of the average melting capacity of the combustion gas flowing out from the raceway.
It means that there is only one. It is presumed that this is the main cause of lower furnace inertness during all coke operation.

Therefore, judging from the melting capacity at the tuyere level, O / C near the furnace wall during all coke operation and average O during charging
It is desirable to set the ratio of / C, that is, the relative O / C (γ ^* ) of the furnace wall to 0.56. However, in the actual blast furnace operation, the charge falling in the vicinity of the furnace wall receives frictional resistance from the furnace wall. Therefore, especially in the morning glory, the descent rate of the charge decreases and the residence time in the furnace increases. Therefore, in consideration of the fact that the temperature rise by heating from the gas rising in the furnace has an advantageous effect, the relative O / C (γ ^* ) in the vicinity of the furnace wall during the all coke operation is set to 0.
Set to a value in the range 6-0.9.

Next, the relative O / C (γ) of the furnace wall when pulverized coal was injected
Can be calculated using the above equation (1) by _assuming that is directly proportional to the melting capacity index I _fp of the furnace wall.

Here, the value of the melting capacity index I _fp of the furnace wall portion at the time of pulverized coal injection may be determined by reading it from FIGS. 7 (a), (b) and (c), but is determined more accurately. If desired, the melting capacity index I _fp , the distance L (m) between the pulverized coal injection position and the tuyere tip, the particle diameter dp (mm), and the pulverized coal injection amount R
It can be calculated as a function of pc (Kg / t).

That is, I _fp is a dependent variable, R pc is an independent variable, and I _fp is related to R pc based on the least squares method.
The equation (17)-(21) below is an equation for estimating I _fp approximated by a second-order polynomial, and FIG. 1 is a relationship diagram between I _fp and Rpc based on the equation.

When 0.2 <L ≦ 0.5 and 0.3 <dp ≦ 0.6; When 0.2 <L ≦ 0.5 and 0 <dp ≦ 0.3; When 0 <L ≦ 0.2 and 0.3 <dp <0.6; When 0 <L ≦ 0.2 and 0 <dp ≦ 0.3; Here, x = Rpc / 100 (21) As is clear from FIG. 1, I _fp tends to increase with the increase of Rpc, L, and dp.
I _fp changes slightly due to changes in c, L, and dp. Therefore, in the present invention, for accuracy,
Although I and _fp were stratified and I _fp was approximated by the cubic formula of Rpc,
It is needless to say that a quadratic equation or a linear equation can be approximated by allowing an increase in error.

As described above, the melting capacity index I _fp of the furnace wall is determined by the calculation based on FIG. 7 or FIG. 1 or the formula (17)-(21), and (1)
Although the method of calculating the appropriate relative O / C (γ) of the furnace wall at the time of blowing pulverized coal according to the blowing condition of pulverized coal was explained by the formula, in the actual blast furnace operation, γ is the calculated value. It is necessary to judge whether or not they coincide with each other. Therefore, in the method of the present invention, the conventional measurement method described below is used to measure the O / C in the vicinity of the furnace wall, or various mathematical expressions are used. Estimate by model.

The vicinity of the furnace wall in the present invention means a region within 1 m from the furnace wall, and the O / C in the vicinity of the furnace wall is easy from the layer thickness ratio of ore and coke in the region and the respective bulk specific gravities. Since it can be calculated, the layer thickness ratio of ore and coke near the furnace wall can be detected.

In order to measure the layer thickness ratio by the detection end,
That is, at the top of the layer where the ore is agglomerate, it is possible to measure by the conventional measuring method, for example, by using a sounding type, microwave type, or laser type profile meter, charging of the ore and coke at every charging It can be determined by measuring the surface shape and calculating the layer thickness of ore and coke. In addition, it can be obtained by measuring the layer thickness ratio of ore and coke at a position where a magnetometer type or electric resistance type layer thickness gauge is installed in the packed bed of the massive band.

In the present invention, the set position of the lumpy band means the installation position of the top of the layer or the detection end. In addition, the layer thickness ratio of ore and coke near the furnace wall at the top of the layer is determined by various mathematical models for estimating the distribution of the charge (for example, the Iron and Steel Institute of Japan, 71 (1985), A5-A
24), the estimation can be performed with relatively high accuracy. Therefore, the O / C in the vicinity of the furnace wall and the relative O / C (γ) of the furnace wall are determined by either the detection end or the mathematical model.
Can be estimated.

(Example) FIG. 8 shows a pulverized coal injection amount Rpc of 60 kg / t to 100 kg.
CO, which is an important operation index of the blast furnace when increasing to / t
The graph shows the time-series transition of the gas utilization rate ηco and the ventilation resistance index K value over a 10-day average. The injection positions of various types of pulverized coal and the distance between the tuyere tips, the particle size of the pulverized coal, and the pulverized coal FIG. 8 shows the result of adjusting the relative O / C (γ) of the furnace wall by the tilt angle of the movable armor or the swirling chute or the number of swiveling of the swirling chute by the method of the present invention according to the blowing amount of As shown, CO gas utilization rate ηco
And the decrease of the airflow resistance index K value made it possible to continue efficient and stable operation. Since the drop position of the charge at the top of the layer can be changed by adjusting the tilt angle of the movable armor or turning chute, the deposit position of ore and coke can be changed by changing the tilt angle of each ore and coke when charging. The amount of ore and coke deposited at the depositing position was adjusted by adjusting the number of turns of the swirling chute.

(Effects of the Invention) As described above, according to the method of the present invention, it is possible to estimate an appropriate O / C in the vicinity of the furnace wall as seen from the melting capacity at the tuyere level, depending on the pulverized coal blowing conditions. Therefore, the effect of the present invention is extremely great because it can contribute to stabilization of blast furnace operation and improvement of efficiency.

[Brief description of drawings]

FIG. 1 is a diagram showing the influence of the pulverized coal injection amount, the pulverized coal particle size, and the pulverized coal injection position on the melting capacity index of the furnace wall in the method of the present invention, and FIG. A schematic side view of the raceway furnace used, FIGS. 3 (a) and 3 (b) are side views of the pulverized coal injection method, and FIGS. 4 (a) and 4 (b) are raceway furnaces during all coke operation. Showing the gas composition distribution and the gas temperature distribution in the tuyere level furnace radial direction, and FIGS. 5 (a) and 5 (b) are the gas composition distributions in the tuyere level furnace radial direction of the raceway furnace when pulverized coal was injected. And FIG. 6 are diagrams showing the gas temperature distribution, FIG. 6 is a schematic diagram for calculating the gas flow velocity distribution in the raceway, and FIGS. 7 (a), (b), and (c) are melting capacity indices of the furnace wall. FIG. 8 shows the relationship between the amount of pulverized coal injected and the particle size and injection position as parameters. FIG. 8 shows the effect of the present invention on the operation of the blast furnace. It is to figure. 1 ...... Tuyere 2 ...... Raceway 3 ...... Raceway furnace top manhole 4 ...... Top gas duct gas sampling hole 5 ...... Raceway furnace flue 6 ...... Raceway furnace 7 ...... Blow pipe 8: Burner for blowing pulverized coal 9: Pulverized coal 10: Hot air generator 11: Horizontal probe 12: Coke

Claims (1)

[Claims] 1. A pulverized coal injection operation in a blast furnace,
The weight ratio of (ore / coke) in the vicinity of the furnace wall within 1 m from the furnace wall at the setting position of the massive zone is calculated, and the ratio of the weight ratio and the average (ore / coke) weight ratio at the time of charging is ( 1) The weight ratio of (ore / coke) in the vicinity of the furnace wall is adjusted by adjusting the tilt angle of the movable armor or the turning chute or the number of turns of the turning chute so as to match γ calculated by the equation. How to operate the blast furnace. Where γ ^* : relative (ore / coke) weight ratio of the furnace wall during all coke operation, I _fp : horizontal distance between pulverized coal blowing position and tuyere tip,
Meltability index of the furnace wall, which is determined by the particle size of pulverized coal and the amount of pulverized coal injected, Melting capacity index of furnace wall during all coke operation.