JPS599115A - Detection of descending behavior and heaped structure of charge in blast furnace - Google Patents

Abstract

PURPOSE:To perform titled detection at the optional height level in a blast furnace without exerting the influence of the flowing-in of the charge near the furnace top and redistribution on the detection, by determining the fluctuation of the changing speed of pressure between the measuring points at the plural positions apart a distance almost speed to the thickness of a single kind of the charge in the heaped layer in the furnace. CONSTITUTION:The pressure gradient in the layer thickness direction of the charge in a furnace heaped alternately by the fractional charge of ores and coke depends largely on grain sizes and void volume if the flow rate of gas is specified, and if the grain sizes and void volume increase, the pressure gradient decrease. Since the average grain size and void volume of the coke are larger than those of the ores, the pressure gradient changes periodically at the pressure measuring point, and the time when the boundary position of both layers passes the measuring point can be exactly detected from the speed of abrupt change in pressure. If the pressure change is measured with measuring devices 14 on upper and lower sides apart by DELTAL in the height direction, 10, 11 in the figure are obtained, and in the latter, the pressure change delays by a certain time DELTAt. Since DELTAt is the time required for the descend DELTAL of the charge, the descending speed of the charge is v=DELTAL/DELTAt.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for detecting the descending behavior and deposition structure of charges in a blast furnace. This paper proposes an advantageous method for detecting

In blast furnace operation, hot metal temperature, hot metal composition, fuel ratio, etc. are determined by the reduction state of the charge until it reaches the lower part of the furnace.
Controlled by heating conditions, melting conditions, etc. The charge in the blast furnace, which is charged from the top of the blast furnace to form a layered stacked structure, descends in the furnace in the opposite direction to the gas flowing upwards. It is then heated and reduced by contact with the gas, and in this sense, the reduced state of the charge,
The heating state and the state of the melt are affected by a large amount of tx due to the rate of descent of the charge until it reaches the lower part of the furnace. Therefore, the hot metal temperature.

In order to ensure the stability of the cypress industry in terms of composition, furnace heat, etc., it is essential to always accurately grasp the rate of descent of the charge and to properly manage it.

Conventionally, in order to measure the rate of descent of the charge described above, a weight that moves to follow the force of the charge layer is brought into contact with the surface of the charge deposited layer at the top of the furnace. There was a technique to measure the descending speed of the charge.

In the figure, 1 is the movement meter of the plow, 2 is the large bell, and 1 is the 8-bar weight. s 'F wire, 4 is weight, 5 is iron skin, 6
7 is the furnace wall brick, and 7 is the surface of the charge (deposition) layer. As shown in the m1 diagram, the charge deposition globules at the top of the blast furnace furnace wall side 1. : 1 Open the can so that the center side of the furnace is lower (because it is blue, the weight 4 may rotate to the center side, or follow the flow of the charge into the center of the furnace (1111). In the case of this prior art, even if the weight 4 moves abnormally as described above, it is measured by 11° as if the charge had descended inside the furnace. In the conventional method of measuring the descent of the charge i! tq from the moving distance of There was a drawback.

Moreover, in the case of such conventional technology, it is an essential requirement that the weight 4 be located on the deposition surface of the charge, so even if the falling F rate of the charge can be detected, it is not near the deposition surface of the charge. Be limited to behavior about. Therefore, there is a deficiency in that it cannot be said to be representative of the overall descending behavior of the burden in the furnace height direction within the blast furnace.

The purpose of the present invention is to eliminate the drawbacks of the conventional measurement techniques mentioned above, namely, to eliminate the effects of charge flow and redistribution near the top of the furnace, and to eliminate the effects of loading at any height level in the furnace. The object of the present invention is to develop a method suitable for extremely easily detecting the descending speed and sedimentary structure of objects. The gist of the configuration of this invention is to detect the descending behavior and the deposited structure of the charge layer in the furnace where ores and coke are alternately deposited by separately charging them. In this method, measurement points are provided at multiple locations on the furnace body spaced apart by a distance approximately equal to the average layer thickness of one deposited layer formed by a single charge, and the measurement points are measured at each location within the furnace. Measure the change in pressure, determine the rate of pressure change for each type of charge from the measured value of the change in pressure, and determine the rate of fall of the charge from the fluctuation in the pressure change rate measured between the above 1111 fixed points. and eel by charging type
The present invention provides a method for detecting the descending behavior of the contents in a blast furnace and the structure of the pile 1'f#, which uses detection of the falling 0 layer thickness ratio as a % characteristic. The details of its configuration will be explained below.

In a blast furnace, ores and coke are layered 4 tons! These charges are alternately charged separately so as to form a structure, but in principle, these charges descend through the furnace while maintaining the ＠-shaped tank structure and reach the upper part of the molten dripping zone. ;-1-'J"ru.

On the other hand, the pressure gradient dp'dl in the layer 1 direction in a full 3ffI layer like a blast furnace is, where P:R: Force (174Q2) 17: Distance in the furnace height direction 1111F (Cm) ε: Mitsunawa ha 1's niguchi rate (dimensionless) ■〕: Charge jj? ! Seventh child's particle diameter (a7) G: j of gas
Q 41 m4 (f/am” ・sec)/l: Viscosity of gas (S'/crn・sec) ρ: Density of gas (
f/Cm') U: Superficial velocity of gas (σ) 2o double force conversion coefficient #! i (171 weights) As is clear from the above equation (1), under the condition that the gas (mass) flow rate is constant, the particle diameter D y'j'- As it increases, the pressure gradient d
As p/dt decreases and the void ratio ε increases, the pressure gradient d
p/dt decreases.

In short, the average particle diameters of ores and coke charged into the blast furnace are 0.02 m (ore) and 0.0 m, respectively.
5 m (coke), the particle size of coke is larger, and the average void volume ε of both layers is 0.40 and 0.40, respectively.
45, the coke layer is larger. Therefore, the above-mentioned pressure gradient dp/dl and particle diameter D! Comparing the ore layer and coke layer from the relationship between d and void volume ε, the pressure gradient in the ore layer is larger than the pressure gradient in the coke layer due to the smaller particle diameter and pore volume ε. Especially shown.

From the above, if the pressure is measured at a certain point in the furnace, for example, a layer h's of ores with a large pressure gradient dp/dt, a large pressure change will occur when passing through the position of the pressure measurement point, - When a small cox layer with an actual pressure gradient dp'r of 3.1 passes through the 4111 level, a small pressure change will be felt in the spear. By the way, in the blast furnace, Iy4 and coke layer with different pressure gradients dp/dt pass through the fixed point of [F cuff 1111], so the measured pressure change is 11 in both layers. F＞
The big '4'll:, and small changes appear alternately.

AA tgl is the charge drop method I@' 2 cm/mi
n, furnace top pressure 1000 f/c*”, gas mass velocity 0.
2 f 7cm”・-5ea, ore 1 curse JEK 1-
2.3 m below the stock line and 8.2 m under the condition of 0.8 m of coke layer. The following shows the results of theoretically calculating the pressure gradient (temporal change in pressure) for each stratified year based on equation (1) from the pressure changes measured at two locations at f3tn. (・ Even at this position, due to the rapid utility at the time of charging ore □+, 11 and coke, except for y?, a (・bold) x pressure change appears when passing through the ore layer, A small pressure change appears when passing through the coke layer.

In addition, Maki 8 and 1 are based on the 81 calculation results of the i pressure gradient for each 1 i 4 above, excluding the sudden pressure rise during ore and coke charging, at a position of 2.8 m below the stock line. , is a diagram showing the time course of the duration of each pressure change rate determined from the time change of pressure (pressure gradient dp/dt) at , . As shown in this figure, when the ore layer reaches the pressure measurement point, the pressure change rate increases dramatically, and when the coke layer arrives, it decreases rapidly. Therefore, the time when the boundary position 1d between both layers passes the pressure measurement point can be detected very accurately.

In Figures 1F and 8, to is the time required for the ore layer to pass the position of the pressure measurement point in the furnace, and t.

is the time required to pass through the coke layer h'.

The present invention utilizes exactly such ore layer and coke If4.
In this method, the rate of descent of the charge is detected using periodic changes in the pressure gradient (hereinafter referred to as pressure change rate) as it passes through.

Now, if we measure the pressure change at two measurement points separated by an appropriate distance ΔL in the height direction of the blast furnace and find the pressure change rate, the pressure change rate obtained at both positions will be as shown in Figure 8. As shown in FIG. 4, this change appears at the lower measurement point with a delay from the upper measurement point. In the figure, numeral 10 indicates a constant value of the upper measuring point, and numeral 11 indicates a change in the measured value at the fixed point on the T-opening side.

Now, at a certain time t0, the pressure 4 (
11 At a fixed point, if there is a rapid decrease in the rate of solidification h'- due to the change from ore to coke, then the rate of ore that causes this pressure change rate is The boundary between the coke layer and the coke layer passes through the measurement point set in the upper part R after a certain time delay, and the rapid decrease in the rate of pressure change in the lower part b I also occurs with a delay of that time. The boundary between the ore layer of interest and the coke layer passes through the upper pressure measurement point and the FE power kilnization speed jv sharply decreases. The time when the pressure change rate starts to decrease rapidly is t2.
If -4-it, Δj, = j, , -t□ falls asleep, and the proboscis is Δ
It is a comfortable time for the interval L to fall - 4. Therefore,
The descending speed of the charge can be determined using equation (2).

V-Δr, /Δt.

? r, the interval ΔL between the upper and lower pressure measurement points is the range of the average charge layer thickness: i.e., if it is ore, it is the thickness of only ore.
If the average layer thickness formed by the deposited layer is 0.5 to i, o m, then when the time at which a rapid decrease in pressure change rate appears at the upper pressure measurement point is taken as the base point, the F side measurement point It can be said that the initial decrease in the rate of pressure change that appears in the upper part of the ore layer corresponds to the upper part of the ore layer. In short, to determine the corresponding rapid pressure change rate decrease at the top F pressure measurement point for a particular charge layer, ΔL is equal to the average charge no thickness for that charge layer. It becomes necessary to do so.

The figure shows a steel pipe 12.18 inserted into the furnace wall bricks by penetrating the furnace wall at positions 7m and 8m below the stock line in an operating blast furnace with a furnace diameter of 8.8m. This shows the situation in which the pressure inside the furnace is measured by inserting it up to the surface.

FIG. 6 is an example of a time change in the pressure change rate determined from the pressure gradient at the upper measurement point IB and the lower measurement point 1B measured by the method shown in FIG. As is clear from the figure, after a sudden decrease in the pressure change speed f1 appears at the 11th interval t0, which is the upper measurement point 12, ], yn 'F 1
At measurement point 18 of the law, a drastic decrease in the rate of change in LE pressure appears at time t2, which is about 8.5 minutes late, and the unloading rate of this dye bed charge is 1 ・O/8 according to equation (2). -0.12 out of 5
+7t/min.

According to the present invention, in the 51f method as described above, the
Case degree te I! -Can be detected positively &f. Therefore, the time t identified as the ore shown in FIG. , when identified as coke+llt,
c and C, respectively, ore layer thickness lO and coke layer thickness tc
is determined by each equation of θ(.

/, 0-■×to = 8) /c-v
to sit. Detection of ore thickness and coke y in Murudage
-I'd J'l ratio to/lc &t f It can be determined by formula 51.

to/lc = to/to (51 As described above, according to the present invention, it is possible to accurately and easily lower the blast furnace contents with erroneous detection caused by the disturbance W occurring on the deposition surface of the blast furnace contents. Not only the speed can be detected, but also the thickness of the ore layer, the thickness of the coke layer, and the ratio of the thicknesses of both layers can be detected very easily.

In the detailed explanation of the present invention, the case was described in which pressure measurement holes were installed at two locations on the furnace wall, but if the pressure measurement holes are installed in multiple stages in the height direction, they can be installed at any position in the height direction inside the furnace. Naturally, it is possible to detect the rate of descent of the charge. moreover,
If the LE force is measured by inserting a steel pipe into the furnace that has two pressure holes of Φ11 spaced apart by about 0.5 to 1 m and has a structure that allows it to be moved up and down inside the furnace, It is clear that the charge fall rate can be measured at any height level within the furnace.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view showing the state in which the weight is lowered on the surface of the charge pile in the blast furnace, and Figure i2 is 2.8 below the theoretically calculated stock line.
Graph showing the pressure change at the 4th place of m and 8.8m, Asahi 81n1, theoretically calculated stock line lower Q
Figure 4 shows the time course of the pressure change rate at the 2.3 m mark. Figure 5 is an explanatory diagram showing the situation in which the furnace pressure is measured at 7 m and 8 m below the stock line, and PA fi diagram shows the rate of pressure change determined from the pressure measured at 7 m and 8 m below the stock line. Shows the passage of time. -1 graph. 1...") 4i transfer r + d + ≠ measuring device, 2... large bell, 8... 7, Shiso 1) doge wire, 4... carp, 5... iron skin, 6... Furnace wall brick, 7... Charge deposition surface, 8... Pressure change meter n value at upper measurement point,
(+... Calculated value of pressure change gt at measurement point on F side, 10.
...G+) Pressure change rate at the IliO measurement point, 11...
・Pressure change rate at point 1 of 111II below, 12...
Knob for measuring pressure at stock line F 7 m, 1B...Visor for measuring force at stock line F 8 m, 14...Pressure 1 regulator, 15...Knob for measuring pressure at 7 m below stock line Rate of pressure change determined from pressure measurement, 16... Rate of pressure change determined from t+ force measurement at 13 m below the stock line. Patent applicant: Kawasaki Steel Corporation Figure 1 Figure 2 Time (current) Figure 8 Figure 71 □ Time Figure 5

Claims (1)

[Claims] L By separately charging ore and coke,
1) - Conflicts between the state of deposits in the furnace and the layer of materials in the furnace, its falling F behavior and deposition] 1) Set up a point at each location on the furnace body separated by a distance approximately equal to the thickness of the layer. Measure the change in pressure, calculate the force change rate at the charging point from the pressure change measurement, and calculate the pressure change rate f measured between each fixed point.
A method for detecting a deposition structure based on the F-fall behavior of a person inside a blast furnace, which is characterized by detecting the F-fall rate of the charge, the layer thickness for each type of charge, and the blue thickness ratio from tH++.