JPS6032795B2 - Mixed layer detection method for vertical furnace contents - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a furnace, such as a blast furnace or a shaft furnace, in which coke, coalesced ore, pellets, raw ore, etc. (hereinafter simply referred to as ore) are bagged in layers from the furnace throat. This relates to a detection method for detecting a mixed layer that occurs between a deposited layer of ore and coke (hereinafter referred to as an ore layer and a coke layer) by utilizing the difference in electrical resistance between ore and coke. It is.

BACKGROUND OF THE INVENTION Reductive melting furnaces such as blast furnaces and shaft furnaces are usually operated by injecting coke as a reducing agent and heat source and ore as a reductant in a layer from the top of the furnace.

This is because the aim is to maintain a high void ratio in the layer and increase the reduction efficiency by the gas in the furnace by inserting the bushes in layers. The ore layer and the coke layer are deposited with their own oblique angles, and these oblique angles are determined by the size of the furnace, the size of the bag, the particle size, the moxibustion supply pine, the beret, etc. The thickness of the deposited layer of ore scraps and coke scraps in the furnace also changes depending on the type of loading method (bag loading order, bell bag loading, chute bag loading, etc.).

As a result, the gas flow inside the furnace changes and the operation is greatly affected. That is, the thicker part of the ore layer has less gas trailing, while the thinner part has more gas flow.
A nose fit in which this gas flow is significantly disrupted can cause problems such as arm-hanging slips. Therefore, it is possible to accurately measure the thickness of the deposited layer at the time of bagging the raw material, and based on this result, change the method of depositing the raw material or adjust the movable repulsion plate 6 to suit the bagging condition of the furnace. It is necessary to have a layer thickness distribution.

Therefore, in the past, the thickness of the deposited material in the furnace was measured by using the point where the electrical resistance was significantly different between the ore layer and the coke layer, or the point where the magnetic permeability was different between the ore layer and the coke layer. Was. However, despite the fact that the ore and coke are placed in separate bags from the top of the furnace, the deposited form of coke is caused by the impact and difference in density when the ore and coke are placed in the bag, causing them to get caught up and flow into the furnace. The ore and coke are mixed, forming a so-called mixed layer at the boundary between the ore layer and the coke layer. This mixed layer has a significantly greater influence on the gas flow in the furnace than the ore layer and coke layer. That is, generally in a blast furnace, 30
Since coke with a grain size of ~6 arms and ore with a grain size of 7 to 25 are mixed, when these are mixed, the porosity will be the same as when the ore and coke are deposited in a single layer. The gas flow in the furnace is greatly influenced by the gas flow in the furnace. Therefore, in this case, it is important to reliably measure the presence or absence of a layer, the layer thickness, and the mixing ratio of ore and coke. However, the conventional method for measuring the thickness of a deposited layer has a problem in that it is not possible to reliably detect the presence or absence of the mixed layer, the layer thickness, the mixing ratio, etc.

In other words, Fig. 1 shows a conventional layer thickness measurement method that utilizes the difference in electrical resistance between ore and coke. ) Sondes 5A and 5B for measuring the electrical resistance of the charge (hereinafter referred to as "sondes") having electrodes 7 are installed separated by a height, and the charge existing between the 10 electrode and the 1 electrode of each sonde is Construct an electric circuit that can measure the electrical resistance (hereinafter simply referred to as resistance) of the rhomboids, continuously measure and record the resistance of the rhomboids, and determine whether it is an ore layer or a coke layer from the change in resistance. This is to calculate the layer thickness.

An example of signal recording is shown in Figure 3. At a high resistance level (0 mark) indicating an ore layer, the signal is stable with little disturbance, but at a low resistance level indicating a coke layer. (K mark) shows a pattern in which the resistance changes significantly from ○ mark and bell to K mark and bell. The reason for the signal change from the K level to the 0 level at the coke layer level is that in the coke layer with large particle size, the voids are significantly larger than those in the ore layer, so the electrode of sonde 5 enters into these voids, and temporarily This is because the resistance is measured to be extremely high. On the other hand, in the mixed layer that occurs at the boundary between the ore layer and the coke layer, coke grains and ore grains coexist, so when coke grains simmer between the 10 and - electrodes of sonde 5, the K level When the ore grains arrive, the resistance becomes . The resistance becomes ○ level, and the recording signal becomes a pattern that changes between the K level and the ○ level.

In other words, the recorded signal pattern in the coke layer and the recorded signal pattern in the mixed layer are detected as almost the same pattern. As described above, in the conventional layer thickness measurement method, it is almost impossible to distinguish between a coke layer and a mixed layer, and the mixed layer is mostly detected as a coke layer. The present invention solves these problems and is in operation.

This provides a method for continuously measuring the presence or absence of a mixed layer, the thickness of the mixed layer, etc. To explain the present invention based on the drawings, in addition to the conventional method, as shown in FIGS.
B) Install a sonde 5C with one electrode 10 on the same horizontal plane as the level and a distance M away from it, and measure the resistance between the pair of electrodes 7 and 8 on the sonde 5A as shown in FIG. 6A' Resistance is established between the rotating foundation and one electrode 81 (ten electrodes in this case) of sonde 5A, (magnetic pole 8 of B sonde when C sonde is installed horizontally on sonde 8), and electrode 8 of sonde 5C. The present invention is characterized in that a C' circuit for measurement is provided, and the resistance of the charged material can be measured at the same time by the C' circuit.

In this case, the structure of sonde 5C does not necessarily have only one electrode, but may be the same structure as sonde A or B, and sonde 5C and sonde 5A (or sonde 5C and sonde 5B are placed horizontally). If installed, a circuit C' that can measure the resistance between the sondes 5B) may be provided.

By doing this, for example, even if a resistance change is detected in the A' circuit of sonde 5A in a storm-like pattern with a coke layer, the resistance in the C' circuit between sonde/5A and sonde 5C will be detected as a signal similar to that in an ore layer. If so, that layer is a mixed layer, and if there is a pattern of an ore layer or a coke layer in either circuit, it can be seen that the layer is an ore layer or a coke layer.

That is, if an example of a chart of a mixed layer detection signal according to the present invention is illustrated, as shown in FIG.
The signal of the A' circuit is shown as A'', the signal of sonde 5B is shown as B'', and the signal of the C' circuit of sonde 5A and sonde 5C is shown as C''. In the signal of A'', the pattern of the coke layer is the point However, in the C'' signal, the time from the mouth point to the point C is considerably shorter than the detection time from A to 2. It means that the mixed layer was detected from time and time t to 2. Also, from this measurement example, to measure the layer thickness of the mixed layer, use sonde 5A and sonde 5 as in the conventional method.
The charge descending speed V may be calculated from the boundary layer detection time difference t at B. That is, Vi--V: Parallel descent speed, So: Distance between sondes 5A and 5B LMix = V x tM...LMix = Mixed layer thickness from A to mouth LMx' = V x tM2...LMix' = From C The mixing ratio of ore and coke in the mixed layer can be easily estimated from the signal pattern in the tM and tM2 time periods in the A'' signal chart of the A' circuit.

In other words, in a mixed layer with a high mixing ratio of ores, sonde 5
Since the probability that the A electrode comes into contact with coke is small, the signal level rarely changes from the 0 level to the K level. In addition, in a mixed layer with a high mixing ratio of coke,
The signal level is ○ because the probability of contact with coke increases.
It will change drastically from level to K level. In addition, in the present invention, the sonde mounting arrangement is determined by the distance between sonde 5A and sonde 5C installed on the same plane (the distance between sonde 5B and 5C when installed horizontally with sonde 5B), and the distance between sonde M and sonde 5A (or sonde 5B). It is essential that the distance between the electrodes 7 and 8 has the following value: it is approximately the same as the average particle size of the coke particles to be placed in bags in the furnace; The average particle diameter is in the range of 2 to 20 times. 〆＾If the particle size is larger than the coke particle size, the mixed layer will have the same signal pattern as the ore layer. If the straddling M is too small or too large, a clear mixed layer cannot be determined. As described above, according to the present invention, a remarkable effect can be obtained in that a layer of bagged ore and coke, and a mixed layer composed of a mixture thereof, can be clearly detected in a furnace such as a blast furnace.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing the conventional method, and Fig. 2 a and b are diagrams showing an example of the structure of a sonde in the conventional method. 3 is an example of signal recording in the conventional method, and FIGS. 4a and 4b are explanatory diagrams showing the mixed layer detection method according to the present invention. The former is a horizontal cross-section, the latter is a vertical cross-section, and FIG. 5a , b are diagrams showing structural examples of the sonde according to the present invention, and the former is a longitudinal cross-sectional view;
The latter is a visual agnosia view x-x. FIG. 6 is an explanatory diagram of the arrangement and circuit of the sonde in the present invention, and FIG. 7 is an example of signal recording in the present invention. 1
is the furnace hard, 2 is the coke layer, 3 is the ore layer, 4 is the mixed layer, 5
A, 5B, and 5C are sondes, 6 is a movable repulsion plate, 7 and 8 are electrodes, and 9 is an insulator. Figure 1 Figure 2 Figure 3 Figure 5 Figure 4 Figure 6 Figure 7

Claims (1)

[Claims] 1 In a method for measuring the layer thickness of different types of charges in a vertical furnace using differences in electrical resistance, 5A installed at different heights
, 5B Place sonde 5C at the horizontal position of one of the two sondes at a distance of lm apart, and measure the electrical resistance with each of sondes 5A and 5B. A method for detecting a mixed layer in a vertical furnace, characterized in that the electrical resistance is measured between the sonde 5A or 5B, and the presence or absence of a mixed layer and the layer thickness are determined from the change in electrical resistance between the two.