JPS5848605B2 - Method for measuring the layer thickness distribution, descending rate distribution, and boundary surface shape of the contents in the reduction melting furnace - Google Patents

Description

[Detailed Description of the Invention] The present invention provides for the
A furnace in which coke, sintered ore, pellets, raw ore, etc. (hereinafter simply referred to as ore) are charged in layers, and the electrical resistance in the deposited layer of coke and ore (hereinafter referred to as coke layer and ore layer, respectively). The present invention relates to a measurement method for measuring the deposition layer thickness distribution, descending velocity distribution, and boundary surface shape of a charge by utilizing the difference in

In reduction melting furnaces such as blast furnaces and shaft furnaces,
Normally, the furnace is operated by charging coke, which serves as a reducing agent and heat source, and ore, which serves as a material to be reduced, in layers from the top of the furnace.

This is because by charging in layers, the void ratio within the layers is maintained at a high level, and the aim is to increase the gas reduction efficiency.

The interface between the coke layer and the ore layer, which are charged into the furnace in layers, is the one located on the top surface of the coke layer (that is, the one located on the bottom surface of the ore layer, hereinafter referred to as the coke layer interface) and the one located on the bottom surface of the ore layer. The one located on the upper surface (that is, the lower surface of the coke layer, hereinafter referred to as the ore layer boundary surface) has a different shape.

The shape of both of the above interfaces depends on the furnace size and charging method (
Bell type, rotating chute type, etc. differ depending on the charging order of coke and ore, and the descending speed of the charge, but the shape of the coke layer interface also depends on the amount and particle size of coke charge, and the ore It differs depending on the charging amount, etc., and is also strongly influenced by the gas flow in the furnace.On the other hand, the shape of the ore layer boundary depends on the grain size of the ore, the sintered ore,
It has the characteristic that it differs depending on the blending ratio of pellets, raw ore, etc.

The respective deposited layer thickness distributions of coke and ore are determined by the combination of the shapes of the two boundary surfaces.

Therefore, the sediment layer thickness distribution changes considerably during operation.

As a result, the gas flow inside the furnace changes, which greatly affects the operation.

That is, the gas flow decreases in areas where the ore layer thickness is large, and conversely, the gas flow increases in areas where the ore layer is thin.

If this gas flow is significantly unbalanced, problems such as shelves, slips, and blow-throughs may occur, making it impossible to maintain normal furnace operation. The charge falling position is changed by a movable repulsion plate to adjust the charge deposit layer thickness distribution and maintain a stable gas flow in the furnace.

This adjustment of the deposited layer thickness distribution achieves its purpose by changing the shape of the boundary surface of the charge.

Therefore, the thickness of the deposited layer and the shape of the boundary surface after charging are accurately measured, and based on these results, adjustments to the movable repellent plate can be made appropriately and quickly to ensure a distribution of deposited layer thickness that matches the operating conditions of the furnace. It is necessary to

At this time, it is also necessary to consider the distribution of descent speed.

However, conventionally, two sondes with a pair of electrodes are inserted into the furnace from the furnace wall at different heights h, and the thickness of the deposited layer and the rate of descent of the charge are continuously measured during operation. Depending on the method, it is not possible to know the shape of the interface from the results of measurements using these two sondes.

Therefore, even if it is found that the charge deposited layer thickness distribution has changed unfavorably due to the use of the two sondes, when adjusting the deposited layer thickness distribution, for example, the movable repulsion plate can be replaced with a coke It is not known at what strength it should be activated for any of the ores.

The present invention provides a method and apparatus capable of simultaneously measuring the coke and ore deposition layer thickness distribution, falling rate distribution, and interface shape continuously during operation.

The measuring method of the present invention is characterized by measuring the vertical height at n points (n≧2) provided in the diametrical direction of the furnace, and at the position of each point on the same vertical line or on a line slightly deviated from it. The total (2
xn) points simultaneously and continuously to measure the electrical resistance of the charge.

That is, the electrical resistance of coke and ore normally used in a reduction melting furnace is, for example, a particle size of 30 m at the top of a blast furnace with a diameter of 8 m.
When coke with a particle size of ~60mm is deposited to a thickness of 300~600 plates, the electrical resistance shows a small value of 1.2~5.0g, but for ore with a grain size of 5~30mm, it shows a resistance of 10,000 times more. The value is tens of thousands of times larger (varies depending on the state of deposition).

This significant difference in electrical resistance allows the coke layer and ore layer to be easily distinguished.

As a measuring device, one set consists of two measuring ends, each having an X pole and a Y pole, located apart by a height h (
That is, it is sufficient that n sets (n is an integer of 2 or more) of the measurement ends are fixed at different positions in the radial direction within the furnace.

FIG. 1 is a vertical cross-sectional view showing an example of an actual furnace when n=3, where 1 is a bell, 2 is a movable repulsion plate that changes the flow of the charge, 3 is a furnace wall, 4 is a coke layer, 5 is an ore layer, 6 is a across-the-board sonde, 7. 7', 8.8', 9.9'
is the measuring end, h is the upper measuring end 7, 8, 9 and the lower measuring end 7'
, 8', and 9'.

FIG. 2 is a cross-sectional view taken along the line AA' in FIG. 10, 10, Y electrodes 11 that are electrically connected to each other, and distances L1, L2, and L3 of each sonde from the furnace wall are shown.

Here, the sonde 6 only needs to reach the position to be measured, and may be a straight type as shown in FIG. 1 or a cantilever type.

Further, the sonde may not be horizontal, but may be inclined along the sedimentary layer.

In addition, the pair of upper and lower measurement ends used to monitor each group can be fixed at different heights h, so they do not need to be on a common sonde as shown in Figures 1 and 2. , it may be attached to two sondes with different heights.

When measuring with direct current, one of the X electrodes and Y electrodes that make up each measuring end is a positive pole and the other is a negative pole, but only one of these two electrodes is connected to the other measuring end. In FIG. 2, only the Y pole is electrically connected through the conductive sonde body.

In FIG. 2, only a single measurement end is partially enlarged and shown in FIG.

FIG. 4 is a sectional view taken along line B-B' in FIG. 3.

10 is a conductor forming an X pole, 11 is a conductor forming a Y pole, and 12 is an insulator interposed therebetween.

The X pole 10, the Y pole 11, and the insulator 12 are concentric tubes as shown in FIG.

Reference numeral 10' denotes an X-pole terminal, which is connected to a terminal outside the sonde through a conductor 13.

Reference numeral 11' denotes a Y-pole terminal, which is electrically connected to the Y-pole of the other measurement end and other terminals outside the sonde via the conductor forming the sonde 6.

In addition, in the measuring device described above, in order to prevent disturbance of the layer caused by the upper measuring end from affecting the lower measuring end, it is preferable to slightly shift both ends in the length direction of the sonde so that they do not overlap on the same vertical line.

By inserting the electrodes of the measuring end fixed on the sonde so that they are in contact with the charge deposited layer, the measuring end located inside the ore layer shows the electrical resistance of the ore, and the measuring end inside the coke layer shows the electrical resistance of the ore. One measuring end shows the electrical resistance of the coke.

During furnace operation, the charge descends sequentially, so by fixing the measuring end, the charge descending speed distribution in the furnace,
It is possible to continuously measure the coke layer thickness distribution, ore layer thickness distribution, and the boundary surface shape of the sediment layer.

That is, when the measuring ends 7 and 7' are installed with a height h apart as shown in Fig. 1, the interface between the coke layer and the ore layer detected by the upper measuring end 7 will be detected by the lower measuring end 7'. It is possible to know the time difference θ (minutes) until the unit layer falls at the measuring end 7 or 7', and also to know the time t (minutes) for the unit deposition layer to fall at the measurement end 7 or 7'.

The elapsed time T (minutes) from to when the boundary surface of interest is detected can be determined.

As a result, the charge descending speed V (Cr/L/min), the unit charge layer thickness t (cfrL), and the reference time T of the boundary surface of interest.

The height difference H(()) between the measurement end and the measurement end is obtained from the following equation.

h(1) ■10,007=V. t (2) H=V.
T (3) The same thing can be seen from the other two sets of measuring ends shown in Figure 1, namely the set of measuring ends 8 and 8' and the set of measuring ends 9 and 9'. From the measured values, the descending speed distribution ■1, ■2, ■3, the deposited layer thickness distribution 1, t2, t3, and an arbitrary time T.

The boundary surface shape L,, H1L2, H2, L3, H
I understand 3.

Figure 5 shows an example of an electrical resistance measurement chart in an actual furnace.
The measurement results in FIG. 5 are summarized and shown in FIGS. 6 to 9.

The horizontal axis is the electrical resistance, and the vertical axis is the time elapsed during the measurement.

In this example, three sets of measurement ends 7 and 7', 8 and 8' and 9
and 9' are 200cWL and 300CIr from the furnace wall, respectively.
L, located at 400m (L1=100, L2=2
00, L32300), the upper measuring ends 7, 8.9 and the lower measuring ends 7', 8', 9' are fixed with a difference of 40 (] in the height direction (h=40).

From the chart in Figure 5, the detection time differences θ1, θ2, θ3 at the interface between the coke layer and the ore layer where the electrical resistance changes rapidly
are 4 minutes, 4 minutes, 4 minutes, and 4.3 minutes, respectively, and the descent times t1, t2, and t3 of a unit pile layer of ore are 7 minutes, respectively.
4 minutes, 5.5 minutes, 4.6 minutes, and the elapsed time T1, T2, which reaches the detection of the Z plane (this is the boundary surface of the upper surface of the coke layer) when the reference time is set to 13 minutes. T3 is 8 each
5 minutes, 5 minutes, 0.7 minutes.

Therefore, from equation (1), the distribution of the descending speed at the positions of the three measurement ends is as follows: ■1 = 40÷4=10(snoring/7n
m), V2=40÷4. 4 = 9. 1(
Snoring/m==), ■3-40÷4. 3 = 9. 3
(crrt/mI7+), and the ore layer thickness distribution is t, = 1 0x 7. from equation (2). 4=7 4 (crr
L), 42=9.1x5.5=50(d), 73=
9.3X 4.6=4 0 (CIIL).

Also, the height of the Z plane based on the upper measurement end level at time 13 minutes is H1=1 0x 8.5= from equation (3).
8 5 (L: 1rL), H2=9.1×5=4
5.5 (crfL), H3=9.3X O. 7
=6.5(crrL).

These results are shown in FIGS. 6 to 8. FIG. 6 shows the descending speed distribution, FIG. 7 shows the ore layer thickness distribution, and FIG. 8 shows the Z-plane shape.

In addition, in Fig. 8, in addition to the case where the reference time is 13 minutes,
The same Z-plane height distribution is shown after 5 and 10 minutes have passed.

According to this, due to the distribution of descent speed shown in Figure 6,
It is known that the shape of the Z plane also changes from moment to moment.

Although the ore layer thickness distribution is shown in Fig. γ, the coke layer thickness distribution can also be determined from the chart of Fig. 5 by a similar method.

By integrating the layer thickness distribution of the ore and coke and the shape of the boundary surface determined as shown in FIG. 8, the deposition state diagram shown in FIG. 9 is created.

FIG. 9 shows the state of accumulation of charge near the level of the upper measurement end at time 18 minutes.

[Brief explanation of the drawing]

FIG. 1 is an explanatory view showing the measuring method of the present invention, FIG. 2 is an explanatory view showing a cross section taken along line A-A' in the previous figure, and FIG. 3 is a partially enlarged view of the vicinity of the measuring end 7 in FIG. Figure 4 is a cross-sectional view taken along line B-B' in Figure 3, Figure 5 is a chart showing an example of measurement results, Figure 6 is a chart showing the descent speed distribution, and Figure 7 is the ore layer thickness distribution. FIG. 8 is a chart showing changes in the shape of the coke layer interface, and FIG. 9 is a chart showing the state of charge deposition. 1: Bell, 2: Movable repulsion plate, 3: Furnace wall, 4: Coke layer, 5: Ore layer, 6: Sonde, 7.7', 8.8', 9
．． 9': Measuring end, 10: Electrode (X pole), 11: Electrode (Y pole), 12: Insulator, 13: Conductor.

Claims (1)

[Claims] 1 One set consists of two measuring ends each having an X pole and a Y pole, located apart by a height h, and n sets (n≧2) of the measuring ends are arranged in the radial direction inside the furnace. The distance Li (i=1.2,...,n
), the interface between the different charge deposits is detected by the change in electrical resistance between the two electrodes of each measuring end, and the subsequent two measuring ends of one measuring end in each set of said measuring ends are The falling time tj of a single deposited layer at the position of each set of measurement ends is determined from the detection time of the two boundary surfaces, and the boundary surfaces are detected at one measurement end of each set of measurement ends from a predetermined reference time. The elapsed time Ti for each set of measurement ends is determined, and the time difference θi between the detection of the same boundary surface by the two measurement ends of each set of measurement ends is determined, and the height h1 of each set of measurement ends Li is calculated.
．． Layer thickness distribution, descent rate distribution, and boundary surface of the charge in a reduction melting furnace, characterized by determining the deposition layer thickness distribution, descent rate distribution, and boundary surface shape of the charge from the descent time ti1 elapsed time Ti, time difference θi How to measure shape.