JPH0754026A - Method for measuring descending position of charged material in blast furnace - Google Patents

Abstract

PURPOSE:To accurately measure the descending distance of charged material by inserting a rigid rod from a furnace top to a fused zone into a filling layer of the charged material in the shaft part of a blast furnace and fiting a position director while using this rigid rod as a guide. CONSTITUTION:The rigid rod 6 is inserted downward from the furnace top into the charged layer 2 in the shaft part of the blast furnace. The position detector 5 connected with a wire 3 through the recessed part 7 provided on the cross section of this rigid rod 6 is dropped on the surface layer 2 of the charged material piled surface at an optional time, and the wire 3 is connected with a dropped distance measuring device 4 at the outside of the furnace along the recessed part 7. By this method, the position of the position detector 5 in the furnace is cleaned by detecting a feeding speed and a feeding quantity of the wire 3 with a descending distance measuring device 4, and the descending speed of the charged material can be found in the optional height in the furnace.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring a descending speed of a charge in a blast furnace and an expansion / contraction state of a blast furnace charge layer at the time of descending.

[0002]

2. Description of the Related Art In a blast furnace operation, the descending state of ore and coke as a charge is an important indicator of the operating state (furnace condition) of the blast furnace. For example, if the charged material suddenly drops abnormally (hanging on a shelf, slipping, etc.), or if such a condition occurs frequently, the quality of the hot metal discharged will change and productivity will decrease due to a reduction in the air flow rate. May fall and sometimes cause serious accidents such as cooling.

The dropping of the charge in such a blast furnace is driven by the melting and dropping of ore that occurs in the so-called lower furnace softening and melting zone and the combustion of coke that occurs in the raceway section.
And, depending on the position and degree of melting and dropping of the ore or coke combustion, the descending speed of the charge in the shaft portion of the blast furnace changes greatly in the radial direction and the depth direction, and the furnace wall profile changes with the change. The charge layer is expanded or contracted due to the flow of the charge at the wall erosion portion, the delay of the fall of the charge at the protrusions such as the deposits on the furnace wall, and the like.

Among these, as the method for measuring the descent rate of the charge in the blast furnace or its spatial distribution, many methods have been disclosed to date, as shown below. And at the same time, those methods had their own problems. For example, (1) Sounding using a weight or a method using a charge bed top profile meter using a laser or microwave is used in a short time from the end time of batch charging to the next start time. Moreover, since it was measured from the upper part of the furnace, the descent rate of the surface layer of the deposit deposition surface was measured, and the measurement area was also limited. Furthermore, it was not possible to know the descent velocity distribution in the depth direction of the charge. (2) Utilizing the difference in electrical resistance between the coke layer and the ore layer,
A measuring method in which an electric resistance measuring sensor is installed in the depth direction of the charge is disclosed in, for example, Japanese Patent Laid-Open No. 52-151606 and Japanese Patent Laid-Open No.
As disclosed in JP-A-2-141257, the measurement result is affected by the temperature and moisture in the furnace, and it is difficult to accurately measure the falling state of the charge. (3) A measuring method in which a magnetometer is installed in the furnace and a change in magnetic flux density detected between the coke layer and the ore layer is used is disclosed in Japanese Patent Laid-Open No. 52-84112, but this method is also used. An error occurred in the measurement due to changes in temperature and moisture, and when a mixed layer of the coke layer and the ore layer was formed, the layer could not be determined and the measurement was not accurate. (4) Further, a method of detecting a load change, which is received by a lance inserted in the furnace according to a change in the unloading state of the furnace interior, as a strain measurement value by a deformation detecting element attached to the lance (for example, (Disclosed in Kaisho 60-248805),
There is also a method (for example, disclosed in Japanese Patent Laid-Open No. 61-91307) in which the load received by the weight inserted into the furnace from the charge is measured via a wire to measure the descending speed of the furnace internal charge.
These methods are limited to measuring the descent rate of the charge at a specific location inside the furnace such as the furnace wall, and require complicated equipment because of the complicated signal processing of the detection element. However, there was a problem that maintenance was complicated for continuous measurement. (5) Furthermore, as a simpler and more reliable method, a wire with a weight at the tip is lowered together with the charge in the blast furnace, and the length of the wire fed into the furnace is changed with time. A method for continuous measurement is disclosed in Japanese Patent Laid-Open No. 58-
37107.

FIG. 2 shows an example of verification of the method described in JP-A-58-37107. The weight 1 is placed on the surface layer 2 of the charged material deposition surface, and then the weight 1 is continuously lowered together with the charged material, and the feeding amount (length) of the wire 3 connected to the weight.
Was measured by the descent distance measuring device 4 outside the furnace. The result is shown in FIG. The feeding speed of the wire 3 is almost constant with time, and the change in the furnace cross-sectional area in the depth direction in the blast furnace shaft portion in the depth direction, that is, the descending speed caused by the change in the cross-sectional area increases as the depth increases The tendency to gradually decrease could not be measured.

This fact means that the wire 3 near the surface layer 2 of the deposit deposition surface descends together with the charge around it, and at the deep inside of the furnace, the wire 3 is as shown by the broken line in FIG. After all, it was considered that the descending speed calculated from the feeding speed of the wire rod only represents the descending speed in the vicinity of the surface layer 2 of the deposit deposition surface. The above is the conventional method of measuring the falling velocity distribution in the radial direction and the depth direction of the charge in the shaft part of the blast furnace and its problems, but the measurement example of the expansion / contraction behavior of the charge layer is It doesn't seem to exist.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems in measuring the descent rate of the furnace interior charge, and the descent rate distribution of the charge in the radial direction of the blast furnace shaft and the charge. The descending velocity distribution in the depth direction and the expansion / contraction state of the blast furnace charge layer at the time of descending are (a) continuously influenced at any position in the furnace without being influenced by the charging sequence of the blast furnace charge, (B) In addition, it is intended to provide a measurement method that can be measured more accurately without being affected by changes in conditions such as furnace temperature and moisture, and (c) that the measurement equipment is inexpensive and easy to maintain. It is a thing.

[0008]

Means for Solving the Problems The inventor has repeated many experiments and researches in order to achieve the above-mentioned object, and descends together with the charge in the charge packed bed to inform the position of the guide rod for the detector. I focused on setting up. That is, the present invention is a plate-like member in which a rigid rod is inserted into a molten zone toward the lower side of the furnace top in the charged material packed layer of the blast furnace shaft portion, and the rigid rod is attached to the lower end of the hanging member as a guide. A blast furnace charge characterized by externally fitting a position detector, lowering the position detector together with the blast furnace charge around the rigid rod, and continuously measuring the descending distance from the furnace top. This is a descent position measuring method. Furthermore, a plurality of the position detectors are attached to the rigid rod on the surface layer of the charge deposition surface at regular intervals, and are lowered together with the blast furnace charge, and the difference in the descending speed of each position detector is continuously measured. This is a method for measuring the descending position of the blast furnace charge characterized by the above.

In this case, the position detector is preferably made of heat-resistant steel, but is not limited to this, and any material having heat resistance and strength such as ceramic may be used. In addition, the hanging material refers to a member such as a wire, a wire, a chain, or a bar.

[0010]

In the present invention, the rigid rod is inserted downward from the furnace top to the melting zone in the charged material packed bed of the blast furnace shaft, and the position detector is attached using the rigid rod as a guide. The position detector does not bend in the charge layer during its descent, and it becomes possible to measure the correct descent distance of the charge, and since the electric resistance and magnetic flux density are not used, It becomes possible to measure the descent distance without the influence of disturbance such as temperature and moisture. The contents of the present invention will be described below with reference to FIGS. 1 and 4 to 5.

FIG. 1 shows a situation in which a rigid rod 6 is inserted into the charge layer 2 on the shaft portion of the blast furnace downward from the furnace top, and the position detector 5 is attached using the rigid rod 6 as a guide. Indicates. The position detector 5 is dropped from above on the surface 2 of the deposit stacking surface at any time, and then descends along the rigid rod 6 along with the fall of the surrounding charges. FIG. 4 is a sectional view of the rigid rod 6, and a recess 7 is provided in the section. The wire 3 connected to the position detector 5 is guided outside the furnace along the recess 7 of the rigid rod 6. As for the position of the position detector 5 in the furnace, the wire feed speed and the feed amount are measured outside the furnace by the descent distance measuring device 4
By detecting by (1), the descending speed of the position detector 5 and the existing position in the furnace are clarified, and it becomes possible to know the descending speed of the charged material at an arbitrary height in the furnace.

Further, a plurality of the same position detectors 5 are lowered together with the charge at a constant time interval, for example, at a time interval of several layers consisting of a combination of an ore layer and a coke layer. Then, the difference between the lowered positions of the respective position detectors 5 is continuously measured. From this, the expansion / contraction state of the blast furnace charge layer existing between the position detectors can be measured in time series. For example, there is a model experimental device that has a half-divided blast furnace reduced model in the vertical direction and covers the divided surface with a transparent plate so that the falling state of the blast furnace charge can be visually observed. By using the two position detectors, the position detectors were lowered along with the charge in a three-layer group consisting of a combination of an ore layer and a coke layer, and the difference between the position detector descending positions was continuously measured. . As a result, it was confirmed that the descending speeds of the two detection ends can measure the expansion / contraction state of the charging material layer such as shelving in time series. At the same time, it was confirmed that it also corresponds to the falling speed of the tracer particles charged.

The equipment required for the present invention is the position detector 5, the rigid rod 6, the wire 3, and the wire feeding device 1.
Only 0 and the descent distance measuring device 4 for measuring / recording the feed amount and speed thereof are required, which is very inexpensive. FIG. 5 shows a position detector 5 mounted so as to move smoothly with respect to a rigid rod.
FIG. As shown in FIG. 5B, the position detector 5 is suspended by the wire 3 passing through the recess 7 of the rigid rod 6.
The shape of the position detector 5 is preferably circular on the plane and inverted bell-shaped on the side, but may be any as long as it smoothly descends in the charging layer. Further, the size of the position detector 5 is such that it does not affect the fall of the charge around it, for example, a circle diameter of 50.
mm or less is preferable.

[0014]

【Example】

(Example 1) Using a reduced model of a blast furnace, the descending state of the charge of the blast furnace was investigated. (A) Method using only position detector and wire (Comparative example 1), (b) Case where the rigid rod 6 according to the present invention and the wire 3 are not housed in the guide structure 7 of the rigid rod 6 (comparison) Example 2) (c) Using the method of the present invention, it was measured at which position in the reduced scale model of the blast furnace the charge on the surface layer of the charge deposition surface was located after an arbitrary time.

FIG. 6 shows a comparison between the measurement result and the measurement result of the charging material descending position using the tracer.
In the case where only the position detector 5 and the wire 3 of (a) (Comparative example 1) or the rigid rod 6 and the wire 3 according to the present invention of (b) are not housed in the guide structure 7 of the rigid rod 6. In (Comparative Example 2), it is found that the wire sags in the model and the accurate position of the position detector 5 cannot be measured. On the other hand, the measured value by the method (c) of the present invention matches the measured value by the tracer. (Example 2) The method of the present invention was applied to a blast furnace having an internal volume of 4500 m ³ .

At the operation time when the state of tapping slag (furnace condition) greatly differs in the circumferential direction in the above blast furnace, the charging position measuring device according to the method of the present invention is used, as shown in FIG. In addition, at two locations in the circumferential direction (south side and north side), the descent rate of the furnace interior contents was measured. The measurement result is shown in FIG.
On the south side and the north side where the position measuring device according to the present invention is installed,
It was found that the distribution of the descending velocity in the depth direction of the charge was different, and the deviation of the descending velocity occurred in the circumferential direction.

In this case, the peculiar descent behavior on the south side shown in FIG. 9 was estimated from the long-term trend of the furnace wall temperature on the south side, and from the measured value of the in-furnace deposit thickness measured during a quiescent period.
It is considered that this is the influence of the formation of the deposit 9 on the furnace wall as shown in FIG. Based on this measurement result, the furnace was recovered as shown in the latter half of FIG. 8 when the air was blown off for the purpose of removing the deposit and the deposit was removed. (Example 3) The present invention was applied to a blast furnace having an internal volume of 4500 m ³ . As shown in FIG. 10, position detectors were installed above and below the ORE (ore) layer, and the difference Δh between the positions of the two position detectors when the charge dropped was measured. FIG. 11 shows the measurement result. The broken line in FIG. 11 is Δ calculated from the volume balance of the charged material in consideration of the furnace body shape (furnace diameter at each height in the furnace).
It is an estimated value of h. The measured value deviates from the value assumed from the above-mentioned volume balance from the middle of the shaft portion, and it can be seen that the layer thickness of the charging layer expands. This is considered to be a phenomenon caused by the expansion of the furnace diameter due to the erosion of the furnace wall.

[0018]

EFFECTS OF THE INVENTION According to the present invention, the rate at which the charge descends at any position in the furnace in the radial direction and the depth direction, and the charge anomaly due to a local anomaly in the descending of the charge due to changes in the furnace wall profile. The expansion / contraction of the bed is 1) not affected by the charging sequence of the blast furnace charge, continuously at any position in the furnace, and 2) unaffected by changes in conditions such as the temperature and moisture in the furnace,
It was possible to measure more accurately.

3) The equipment is also simple, easy to maintain, and inexpensive. Furthermore, by installing a plurality of the present invention in the circumferential direction, the deviation in the circumferential direction of the blast furnace unloading condition can be accurately grasped, and the reactor management technology is improved.

[Brief description of drawings]

FIG. 1 is a view in which a device for measuring a lowered position of a charge according to the present invention is installed in a blast furnace.

FIG. 2 is an explanation of a method of measuring a load descending speed by a conventional method using a weight and a wire.

FIG. 3 is a measurement result by the method of FIG.

FIG. 4 is a cross section of a rigid rod according to the present invention.

FIG. 5 is a schematic view showing a state in which a position detector and a wire are attached to a rigid rod according to the present invention.

FIG. 6 shows the results of Example 1.

FIG. 7 is a schematic view in which the charging descent distance measuring device according to the present invention is installed at two locations in the circumferential direction (Example 2).

FIG. 8 is a situation of pig iron during a period in which a dropping rate of a charged material is measured according to the present invention (Example 2).

FIG. 9 is a measurement example of the charging material descent rate of the second embodiment.

10 is a diagram showing measurement conditions of Example 3. FIG.

11 is a diagram showing the measurement results of Example 3. FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Weight 2 Charge deposit surface layer 3 Wire 4 Falling distance measuring device 5 Position detector 6 Rigid rod 7 Rigid rod recess 9 Furnace wall deposits 10 Wire feed device 11 Bellless charging device chute 12 Blast furnace shaft

Claims (2)

[Claims] 1. A plate-shaped position detector in which a rigid rod is inserted downward from the furnace top into a charge-packed bed of a shaft portion of a blast furnace, and the rigid rod is attached as a guide to the lower end of a suspension member. And the position detector is lowered together with the blast furnace charge around the rigid rod, and the descent position measurement of the blast furnace charge is characterized by continuously measuring the descent distance from the furnace top. Method. 2. A plurality of the position detectors are attached to the rigid rod on the surface layer of the volume surface of the charged material at regular intervals, and are lowered together with the blast furnace charged material, and the difference in the descending speed of each position sensor is continuously measured. The method for measuring the descending position of the blast furnace charge according to claim 1, wherein