JP5561228B2 - Method for measuring fall trajectory of blast furnace charge and measuring rod - Google Patents

Description

  The present invention relates to a method for measuring a fall trajectory of a blast furnace charge and a measuring rod.

  In a blast furnace that produces pig iron, as a charge from the top of the furnace, sinter or block iron ore or the like (hereinafter referred to as iron ore) and coke charged with powdered iron ore are charged alternately, An iron ore layer and a coke layer are formed inside. Hot air blown from the tuyere below the blast furnace reacts with coke before the tuyere to form CO gas, and the CO gas heats and reduces iron ore while rising in the furnace. The heated or reduced iron ore forms a softened cohesive zone and then drops as hot metal. The ore layer and coke layer in the furnace gradually descend in the furnace due to the burning of coke in front of the tuyere and the melting of molten iron in the softening and fusion zone of iron ore. Passes through and accumulates in the furnace bottom to form pig iron.

  The blast furnace charge is charged by a bell type charging device or a bellless type charging device. The charge profile at the top of the furnace has a substantially inverted conical shape with the center at the center vertical direction (axial center) of the blast furnace, and the furnace periphery has a relatively small particle size. The part is generally deposited with a large particle size charge. The charge with a large particle size has a lower resistance to gas flow in the furnace than the charge with a small particle size, and the resistance to gas flow in the furnace is lower with coke than with iron ore. The gas flow in the blast furnace is affected by the ventilation resistance in the radial direction of the furnace due to the charge. Therefore, the charge distribution at the top of the furnace formed by iron ore and coke charged to the blast furnace determines the gas flow distribution in the blast furnace, and the formation of an appropriate charge distribution is extremely important for blast furnace operation. is there.

  Therefore, it is an important technical problem to accurately grasp the trajectory of the charge from the charging device. However, the iron ore and coke charged into the blast furnace are so large that the bell liner wears in the case of the bell type charging device, and the swirl chute liner wears in the case of the bellless type charging device. As a result, there is a problem that the fall trajectory of the charge from the charging device changes, and as a result, the charge distribution at the top of the furnace changes. Therefore, in response to the change in the fall trajectory of the charge due to the liner wear, the distribution of the charge at the top of the furnace is adjusted by adjusting the movable armor for the bell-type charging device and the angle of the swivel chute for the bell-less charging device. However, in order to cope with such changes in the load trajectory due to liner wear over time, it is necessary to accurately grasp the load trajectory regularly. Become.

  In the blast furnace, scheduled wind breaks are performed after continuous operation from January to February. The scheduled rest wind is to temporarily stop hot air blowing from the tuyere, and repair the blast furnace equipment within the hot air blowing stop time. What is necessary is just to measure the fall locus | trajectory of a blast furnace charge at the time of operation stop of a scheduled rest wind. From January to February, a large amount of iron ore and coke was charged into the blast furnace, and the falling trajectory of the blast furnace charge changed due to the wear of the swivel chute charged with the charge. It is for grasping correctly. Measure the fall trajectory of the blast furnace charge when the repair items for all facilities are complete and the furnace top charging device is ready for use. In this case, if it takes a long time to measure the fall trajectory of the blast furnace charge, the rest time becomes longer and the productivity of the blast furnace deteriorates. Therefore, the method for measuring the trajectory of the blast furnace charge must be able to be measured easily and in a short time.

  As a specific measurement method that has already been disclosed, a sound is generated when a probe is inserted in the transverse direction of the blast furnace at a position below the swivel chute for charging the charge and the load collides with the probe. There is an apparatus for estimating the fall position of a charge in a blast furnace that detects a signal and detects the arrival time of an acoustic signal propagating through an acoustic transmission rod (Patent Document 1).

  According to the present invention, it is possible to detect the impact position of the charge in the blast furnace radial direction, but the sound transmission speed is affected by the temperature, and the correction is necessary and complicated, and the cost of the apparatus is increased. .

There is a blast furnace raw material fall position detection method in which a collision bar is fixed between a blast furnace charging swivel chute and a furnace top raw material, and the generated pseudo AE is detected by detection sensors at both ends (Patent Document 2).
According to the present invention, by fixing the bar, it is possible to always measure regardless of the blast furnace off-air, but there is a problem that the bar is heavily worn and maintenance is difficult.

There is a device that inserts the probe in the transverse direction of the blast furnace at the lower position of the swivel chute for charging the charge, and measures the fall trajectory of the charge by changing the pressure of the gas supply pipe in the probe (patent) Reference 3).
According to this method, the collision position of the charged material in the blast furnace radial direction can be detected, but in an environment where there is a lot of dust at the top of the blast furnace, there is a problem that the gas supply pipe of the probe is easily clogged and the measurement accuracy is poor.

  By inserting the long body into the blast furnace, applying the raw material falling in the blast furnace to the long body, and detecting the change in acceleration caused by the collision of the raw material in the longitudinal direction of the long body, the longitudinal direction of the long body There is a method of grasping the distribution of the amount of falling material (Patent Document 4). According to the present invention, it is possible to grasp the distribution of the fall amount of the blast furnace charge by the acceleration change due to the collision of the fallen object, but the apparatus is complicated and there is a difficulty in simple measurement.

JP-A-9-235605 JP-A-3-207804 JP-A-61-177304 JP 11-315309 A

  The detection of the drop position when charging the raw fuel into the blast furnace and the grasp of the drop trajectory are important indicators for the operation of the blast furnace. There have been proposed methods for detecting changes in the vibration and acoustics of the measuring rod inserted on the surface of the blast furnace charge, changes in pressure in the gas conduit, and changes in acceleration due to material collisions. Then, the accuracy was poor, and it was a problem in terms of maintenance.

  An object of the present invention is to provide a method that can accurately measure the fall trajectory of a blast furnace charge even in an environment where there is a lot of dust at the top of the blast furnace. It is another object of the present invention to provide a method for measuring the fall trajectory of a blast furnace charge and a measuring rod that are less difficult to maintain and can be measured easily and in a short time.

  The inventors insert a measuring rod wrapped with a pressure measuring film between the charging device in the blast furnace and the charging surface in the furnace, and the dropped charging contacts the pressure measuring film. It was found that the trajectory of the blast furnace charge can be measured accurately and easily by measuring the pressure.

  The present invention has been made to solve the above problems based on this finding, and the gist of the present invention is as follows.

(1) A method for measuring the fall trajectory of a blast furnace charge for measuring a charge fall trajectory when charging the charge into a blast furnace,
Inserting a measuring rod wrapped with a pressure measuring film between the charging device in the blast furnace and the charging surface in the furnace;
Dropping the charge onto the measuring rod and coloring the pressure measuring film with indentations;
A method for measuring a fall trajectory of a blast furnace charge, including a step of obtaining the number of indentations and the pressure of each indentation from the measured indentations recorded on the pressure measurement film.
(2) The method for measuring a fall trajectory of a blast furnace charge according to (1), further including a step of measuring a fall trajectory for each particle size of the charge by a pressure sensed by the pressure measurement film.
(3) From a core rod, a pressure measurement film covering a part of the upper surface of the core rod, and a protective film having a function of preventing damage during measurement of the pressure measurement film covering the entire upper surface of the pressure measurement film Measuring rod for the trajectory of the blast furnace charge.

  ADVANTAGE OF THE INVENTION According to this invention, the fall locus | trajectory of a blast furnace charge can be measured accurately also in an environment with much dust at the top of a blast furnace. In addition, there is little difficulty in maintenance, and the fall trajectory of the blast furnace charge can be measured easily and in a short time.

The figure which shows the measuring apparatus of the fall locus | trajectory of a blast furnace charge. The figure which shows the cross-section of a measuring rod (AA cross section in FIG. 1). The figure which shows the fall locus | trajectory of an iron ore. The figure which shows the pressure of each indentation.

  The present invention relates to a blast furnace charge trajectory measurement method for measuring a charge fall trajectory when charging a charge into a blast furnace. A step of inserting a measuring rod wound with a pressure measuring film between the surfaces of the entrance, a step of measuring a pressure when the charge falls and contacts the pressure measuring film, and the pressure measurement This is a method for measuring the fall trajectory of a blast furnace charge comprising a step of analyzing the indentation of the film.

  The present invention accurately measures the trajectory of the blast furnace charge by measuring the impact of the blast furnace charge falling into the furnace from the blast furnace charge charging device on the pressure measuring film. .

  The blast furnace charge falls into the blast furnace by gravity from a charge charging device such as a charging bell or a swivel chute. FIG. 1 shows an apparatus for measuring the trajectory of a blast furnace charge. The measuring rod 1 according to the present invention is inserted from the outside of the furnace between the lower end of the charging apparatus and the surface of the furnace interior.

  In FIG. 1, when the charging device is a turning chute, the charge 3 is charged from the turning chute 4 toward the charge surface 5 at the top of the blast furnace. The turning chute 4 continuously rotates while maintaining a constant angle θ with respect to the vertical center of the blast furnace. Since the turning chute 4 continuously rotates, the charge 3 can be uniformly charged in the blast furnace circumferential direction. Moreover, the turning chute 4 can change the drop position of the charge 3 in the blast furnace radial direction by changing the angle θ. That is, when the angle θ is small, the charge 3 falls near the furnace center, and when the angle θ is large, the charge 3 falls near the furnace wall.

FIG. 2 shows a cross-sectional structure of the measuring rod 1. Although the center is the core rod 1a, FIG. 2A illustrates the case of a round pipe, and FIG. 2B illustrates the case of a square pipe, the cross-sectional shape and material thereof have sufficient rigidity at the time of measurement. What is necessary is just to determine suitably.
A pressure measuring film 2 is placed on the surface of the core bar. The winding range needs to include the entire range in which the charged material falls in the furnace radial direction (core bar longitudinal direction), but may be appropriately determined in the furnace circumferential direction (core bar width direction). From the viewpoint of measurement accuracy, as shown in FIG. 3, it is most preferable to use the entire upper surface where the number of indentations is the largest. Here, the pressure measurement film is a film having a function in which a portion that receives pressure emits light and shade according to the pressure, and a commercially available product is selected according to the measurement target. Generally, for example, it is used for pressure measurement such as contact pressure of a roll, tightening pressure of fastening parts of various machines, winding pressure of paper or the like. However, there is no case of measuring the solid flow by colliding the solid particle flow with the pressure measurement film, and there is no case of measuring the characteristics of the charge dropping trajectory of the blast furnace.
A protective coating 1b is provided so as to surround the pressure measurement film. In the blast furnace, the amount of ore charged per time is as high as 50 to 100 tons, so that the pressure measuring film 2 on the surface of the measuring rod 1 is broken by the ore drop impact. In order to prevent the pressure measurement film from being damaged, a film for protecting the film is required. However, if the protective film is too strong, the pressure measurement film cannot detect the impact force of ore dropping. As a result of examining kraft adhesive tape, cloth adhesive tape, and various film tapes as a film for protecting the pressure measurement film, the present inventor has determined that the cloth adhesive tape has appropriate strength and is easy to remove. It was found that it is optimal for the analysis of post pressure.

  Next, with the measuring rod 1 inserted into the blast furnace, the blast furnace charge 3 is dropped from the charging device, and the blast furnace charge 3 is caused to collide with the pressure measuring film 2 of the measuring rod 1. The portion of the pressure measuring film 2 of the measuring rod 1 where the blast furnace charge collides is usually colored red due to the impact force. For example, one grain of iron ore that is a charge leaves a trace on the film. At this time, the magnitude of the acting force is expressed by a red density. The number of particles in the blast furnace charge can be determined from the number of contact points, and the flow width of the blast furnace charge can be grasped from the position of the contact point. And since the density | concentration of red changes with the magnitude | size of the impact force by particle | grains, the charge particle size can be grasped | ascertained. That is, it can be seen that large particles collide with a portion where the concentration of red is dark and fine particles collide with a portion where the concentration is low.

  In the present invention, the main flow of the charge flow and the width of the charge flow can be measured. The pressure measurement film with which the charge collided is taken out of the furnace and analyzed by the pressure image analysis system, so that the main stream position, width and charge particle size distribution of the blast furnace charge can be grasped.

Next, examples of the present invention will be described, but the present invention is not limited thereto.
The present invention was carried out when the charge charging device was a blast furnace with a swirl chute. A measuring rod 1 having a diameter of 90 mm was inserted from the outside of the furnace between the lower end of the turning chute 4 and the furnace interior entrance surface 5 (FIG. 1). A pressure measuring film 2 (manufactured by Fuji Film, product number MW) was placed on the surface of the measuring rod 1, and further coated with a cloth adhesive tape.

  The color developed by pressurization due to the collision of iron ore was analyzed by a pressure image analysis system after the color development information was read with a scanner and digitally converted.

  In FIG. 3, the fall locus | trajectory of the iron ore measured by this invention is shown. θ is an angle formed by the turning chute with respect to the vertical (see FIG. 1). When the left side is the furnace center and the angle θ is 30 °, it indicates that the main flow of the iron ore fall is on the side close to the furnace center. When the angle θ is 50 °, it indicates that the main flow of iron ore fall is on the side closer to the furnace wall. FIG. 4 is a plot of individual pressure values when the angle θ of FIG. 3 is 50 ° and 30 °. Since the speed of the iron ore when colliding with the measuring rod 1 is constant regardless of the size of the particle size, the difference in weight, that is, the size of the pressure value detected by the difference in particle size is determined. When θ in FIG. 4 is 50 °, the pressure value on the furnace center side is large and the pressure on the furnace wall side is small within the range in which the pressure is detected. This means that many large iron ores collided with the furnace center, and many small iron ores collided with the furnace wall. When θ in FIG. 4 is 30 °, it means that many large iron ores collided with the furnace wall and many small iron ores collided with the furnace center. Thereby, the fall locus | trajectory for every particle size of a charge can be measured with the pressure which a pressure measurement film senses.

  According to the present invention, even if the charge trajectory changes due to wear of the charge charging device, etc., the main flow of the charge trajectory, the width of the charge flow, and the fall trajectory for each charge particle size are measured. Depending on the measurement result, the bell-type charging device can be adjusted to move armor, and the bell-less type charging device can adjust the swivel chute angle to respond to changes in the fall trajectory of the charge. Stable operation of the blast furnace becomes possible.

  The present invention is capable of accurately measuring the trajectory of the blast furnace charge even in an environment where there is a lot of dust at the top of the blast furnace. A method by which a trajectory can be measured is provided.

DESCRIPTION OF SYMBOLS 1 ... Measuring rod, 1a ... Core rod (pipe), 1b ... Protective film 2 ... Pressure measuring film, 3 ... Charge, 4 ... Turning chute, 5 ... Charge surface

Claims (3)

A method for measuring a fall trajectory of a blast furnace charge for measuring a charge fall trajectory when charging a charge into a blast furnace,
Inserting a measuring rod wrapped with a pressure measuring film between the charging device in the blast furnace and the charging surface in the furnace;
Dropping the charge onto the measuring rod and coloring the pressure measuring film with indentations;
A method for measuring a fall trajectory of a blast furnace charge, including a step of obtaining the number of indentations and the pressure of each indentation from the measured indentations recorded on the pressure measurement film.   The method for measuring a fall trajectory of a blast furnace charge according to claim 1, further comprising a step of measuring a fall trajectory for each particle size of the charge by a pressure sensed by the pressure measuring film.   Blast furnace equipment comprising a core rod, a pressure measuring film covering a part of the upper surface of the core rod, and a protective film having a function of preventing damage during measurement of the pressure measuring film covering the entire upper surface of the pressure measuring film Measuring rod for the trajectory of falling objects.

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