JP2014231634A - Flow rate control method of particulate matter in blast furnace - Google Patents

Abstract

The present invention provides a method for controlling the flow rate of a granular material in a blast furnace that suppresses the variation in the flow rate of the granular material blown for each blowing tuyere for a long time in blast furnace operation. A granular material 25 is conveyed to a plurality of blower tuyere 11 with a carrier gas 33, and the granular material 25 is blown into the blast furnace 1 from the plurality of blower tuyere 11. The flow rate of the granular material blown into each of the plurality of blowing tuyere 11 and the carrier gas flow rate corresponding to the flow rate of the granular material are measured a plurality of times within a fixed time. A plurality of powder flow rates obtained by subtracting an average value of a plurality of powder flow rates already measured from a powder flow rate already measured at the target blower tuyere 12 of the blower tuyere 11 And a plurality of carrier gas flow rates corresponding to the granular material flow rates already measured at the target air tuyere 12 are obtained. Based on the relational expression, the flow rate of the carrier gas to the target blower tuyere 12 is determined so that the flow rate of the granular material blown into the target blower tuyere 12 at the time t becomes the average value. [Selection] Figure 2

Description

  TECHNICAL FIELD The present invention relates to a method for controlling the flow rate of a granular material blown in a blast furnace for controlling the flow rate of the granular material blown into a blast furnace from a plurality of blower tuyeres.

  There are pulverized coal, plastic fine powder, etc. as the granular material blown into the blast furnace. The blowing of the granular material into the blast furnace is carried out in many blast furnaces because it has a large cost merit due to the price difference with coke as a reducing material, and greatly contributes to the economic improvement of blast furnace operation. In order to continue the operation of the blast furnace stably, it is important to ensure the core air permeability and liquid permeability in the blast furnace and prevent the core inactivation.

  A plurality of blower tuyere are provided in the circumferential direction on the side wall of the blast furnace, and when the flow rate of the granular material blown into each of the blower tuyere varies, the temperature at the tuyere tip inside the blast furnace of each blower tuyere is Since it does not become constant, there is a possibility that the reduction reaction of the iron ore raw material may not be promoted uniformly at all the tuyere. For this reason, this variation in the granular material flow rate leads to deterioration of the core permeability and liquid permeability and inactivation of the core. Therefore, it is desirable to make the flow rate of the granular material blown into each of the blower tuyere uniform.

  Moreover, if the flow rate of the powder particles becomes uniform, the hot metal temperature discharged from a plurality of outlets provided in the blast furnace becomes uniform. Then, in the next steelmaking process, since the hot metal obtained at each outlet has a uniform hot metal temperature, the amount of heat applied to this hot metal can be made constant, and the refining process can be performed. Efficient refining treatment becomes possible.

  Patent Document 1 includes one pressure vessel for storing pulverized coal, a plurality of transport pipes connected to the pressure vessel, and booster pipes connected to the respective transport pipes. The pulverized coal transport equipment that transports charcoal is described, and the amount of pulverized coal that passes through the transport pipe with a long distance from the pressure vessel to the blower tuyere is smaller than that that passes through the short transport pipe. There is a problem that it tends to be small, and the pulverized coal cannot be evenly distributed to each air tuyeres. In order to solve this problem, the method of adjusting the amount of pulverized coal injection in Patent Document 1 determines the booster flow rate flowing through the booster pipe connected to each transport pipe in a state where the pressure in the pressure vessel is kept constant as the pressure loss. The amount of pulverized coal cut out per unit time from the pressure vessel to each transport pipe is adjusted by changing the pressure individually at the transport pipe end pressure.

JP 58-74426 A

  In the invention of Patent Document 1, when the booster flow rate (referred to as “carrier gas flow rate” in the present invention) is set for each transport pipe, variation in the flow rate of pulverized coal blown into each blower tuyere is suppressed to some extent. However, as the blast furnace operation time elapses, each transport pipe may become clogged, and there may be a phenomenon in which the variation in the flow rate of pulverized coal that passes through each transport pipe and is blown into the blower tuyere gradually increases. is there. For this reason, in invention of patent document 1, there exists a problem that the dispersion | variation in the blowing amount of pulverized coal cannot be suppressed over a long time.

  The present invention has been made in view of the above problems, and the object of the present invention is to provide a blast furnace that suppresses variations in the flow rate of the granular material blown into each blower tuyere (transport pipe) for a long time in blast furnace operation. It is to provide a granular material flow rate control method.

  The present inventors, when transporting the granular material with a carrier gas of a constant flow rate, the reason why the variation in the flow rate of the granular material that passes through the transport pipe and is blown into the blowing tuyere increases as time passes. As a result of intensive investigations, the condition that the granular materials flow through them, such as fluid resistance in the transport pipes and ventilation tuyere, is adhered to the inside of each transport pipe and ventilation tuyere. I found out that it would change. Therefore, the flow rate of the granular material blown into each of the plurality of blower tuyere is measured, and the flow rate of the granular material blown into the target blower tuyere among the multiple blower tuyere is measured. The carrier gas flow rate was determined so as to obtain an average value of the granule flow rate, and the present invention for conveying the granular material at the carrier gas flow rate was completed.

That is, the gist of the present invention for solving the above problems is as follows.
A method for controlling a granular material flow rate in a blast furnace, in which a granular material is conveyed to a plurality of blower tuyers with a carrier gas, and the granular material is blown into the blast furnace from the plurality of blower tuyere. A plurality of powders measured at each measurement time mt by measuring the flow rate of the granular material blown into each of the blower tuyere and the carrier gas flow rate corresponding to the flow rate of the granular material a plurality of times. Deviation of a plurality of granular material flow rates obtained by subtracting the average value of the granular material flow rate from the granular material flow rate measured at each measurement time mt at the target blowing tuyere among the plurality of blowing tuyere And a plurality of carrier gas flow rates corresponding to the granular material flow rate, which is a subtraction subtraction for calculating the deviation, and based on the relational equation, blown into the target blower tuyere at time t The carrier gas flow rate to the target blower tuyere is determined so that the flow rate of the granular material becomes the average value. Granular material flow control method in a blast furnace, characterized in Rukoto.

  ADVANTAGE OF THE INVENTION According to this invention, the dispersion | variation in the flow volume of the granular material blown in for every ventilation tuyere (transport pipe) can be suppressed over a long time in blast furnace operation, and blast furnace operation can be continued stably. As a result, the temperature at the tuyere tip inside each blower tuyere becomes constant, and the reduction reaction of the iron ore raw material is uniformly promoted at all tuyere tips, and the deterioration of the furnace core air permeability and liquid permeability and the furnace core Deactivation can be suppressed and the reducing material ratio can be reduced.

  Furthermore, since the hot metal temperature discharged from a plurality of hot metal outlets becomes uniform, the hot metal having a uniform hot metal temperature can be refined in the steelmaking process as the next step. Therefore, since the refining process can be performed with the same amount of heat with respect to the hot metal obtained for each outlet, an efficient refining process is possible.

It is a top view of a blast furnace. It is explanatory drawing which shows the granular material blowing equipment which supplies a granular material to the ventilation tuyere which comprises the 1st group shown in FIG. It is a graph which shows the example of the relationship between the deviation of a carrier gas flow rate and a granular material flow rate. It is a graph which shows the example of the time-dependent change of the flow rate of the pulverized coal blown into each ventilation tuyere in a comparative example. It is a graph which shows the example of a time-dependent change of the flow rate of the pulverized coal blown into each ventilation tuyere in the example of the present invention.

  Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a plan view of a blast furnace. The blast furnace 1 has a substantially circular shape when viewed from above, and in this embodiment, forty air blowers 11 are provided on the side wall of the blast furnace 1 at approximately equal intervals along the circumferential direction. The leftmost air outlet is the first air outlet 11a, and the air outlets 11b arranged in the counterclockwise direction from the first air outlet 11a are the second air outlet 11b and the third air outlet 11c. ,..., 39, 40. The blower tuyere 11 closest in the clockwise direction from the first blower tuyere 11a becomes the 40th blower tuyere, and the rightmost blower tuyere becomes the 21st blower tuyere.

  The granular material is supplied to the blast furnace 1 through the plurality of blower tuyere 11 described above. In the blast furnace 1, the coke thrown into it or the granular material blown into it acts as a reducing material, and the iron ore thrown in is reduced and melted to obtain hot metal. In the blast furnace 1, a plurality of tap holes 13 are provided below the blower tuyere 11 (see FIG. 2), and hot metal is discharged from the tap hole 13 to a hot metal ladle or a kneading car.

  The flow rate of the granular material blown into the blower tuyere 11 is managed in a group, and one lift tank 21 that stores the granular material is connected to a plurality of blower tuyere 11 in one group. In FIG. 1, one group includes five blower tuyere 11, forty blown tuyere 11 are divided into eight groups, and eight lift tanks 21 are present. The blower tuyere 11 in FIG. 1 is configured such that the first group consists of No. 1 to No. 5 blower tuyere and the second group consists of No. 6 to No. 10 blower tuyere. However, in order to simplify FIG. 1, illustration of the lift tank 21 connected to each ventilation tuyere of 3rd-8th group is abbreviate | omitted. Actually, there is a granular material blowing facility 2 in each group.

  In the form shown in FIG. 1, the number of the ventilation tuyere 11 is 40 as an example, and the number of the ventilation tuyere 11 constituting one group is five. Is not limited to these numbers. For example, in the present invention, the number of blower tuyere 11 is 20, the number of blower tuyere constituting one group is 20, and one lift tank 21 is connected to 20 blower tuyere. It may be a form.

  FIG. 2 is an explanatory view showing a granular material blowing facility for supplying granular material to the air blowing tuyere constituting the first group shown in FIG. 1. The granular material blowing facility 2 includes one lift tank 21, a plurality of blow pipes 22 inserted into each of the blower tuyere 11 (first to fifth blower tuyere 11), each of the blowpipe 22 and the lift tank 21. Are provided with a plurality of transport pipes 23, a plurality of transport gas pipes 31 that join each of the transport pipes 23, and a transport gas flow rate controller 51.

  The lift tank 21 is connected to a granular material supply mechanism (not shown) such as a coal mill and a pressurizing means 26 such as a blower. Then, it is sent from the powder and granular material supply mechanism to the lift tank 21 and accommodated in the lift tank 21. Further, pressure is applied to the lift tank 21 by the pressurizing means 26, and the granular material 25 is sent from the lift tank 21 to the transport pipe 23. The carrier gas 33 sent by the carrier gas pipe 31 that joins the transport pipe 23 increases the pressure of the powder 25 passing through the transport pipe 23, and the powder 25 passes through the blow pipe 22 and the blower tuyere 11. Supplied to the blast furnace 1.

  Although not shown, the lift tank 21 can measure a change in mass per unit time. For this reason, the mass per unit time of the granular material blown into the blast furnace 1 through all of the blower tuyere 11 can be calculated by measuring the fluctuation of the mass of the lift tank 21.

  The transport pipe 23 is provided with a granular material opening / closing valve 24, and supply of the granular material can be stopped by the granular material opening / closing valve 24. A carrier gas pipe 31 joins the transport pipe 23 between the granular material on-off valve 24 and the blow pipe 22. The carrier gas pipe 31 is provided with a flow rate adjusting valve 32 for the carrier gas 33, and a carrier gas supply source (not shown) for accommodating the carrier gas 33 and a pressurizing means 34 such as a blower are connected to the carrier gas pipe 31. The carrier gas 33 is supplied to the transport pipe 23 via the carrier gas pipe 31 by the pressure of the pressurizing means 34. The flow rate of the carrier gas 33 can be changed by adjusting the pressure of the carrier gas 33 by the carrier gas pressure control valve 32. In order to convey the granular material 25 passing through the transport pipe 23 with the carrier gas 33 that is pumped, the pressure of the carrier gas 33 is adjusted, and the flow rate is changed to blow into each of the blower tuyere 11. The flow rate of the granular material to be adjusted can be adjusted. As the carrier gas 33, air, nitrogen or the like can be used.

  The blow pipe 22 is provided with a granular material flow rate measuring device 41 such as a capacitance type flow meter, for example, and the granular material flow rate measuring device 41 uses the granular material flow rate (t / h (hour)). ) Can be measured. A gas flow rate sensor or the like is further provided in the particulate flow rate measuring device 41, and the flow rate (t / h) of the carrier gas 33 can be measured with the gas flow rate sensor. Thereby, it is possible to acquire a data set of the granular material flow rate (t / h) and the carrier gas flow rate (t / h) at an arbitrary measurement time mt.

  The carrier gas flow rate controller 51 and a carrier gas pressure control valve 32 are electrically connected to the carrier gas flow rate controller 51. The above-described data set acquired by the granular material flow rate measuring device 41 is sent to the carrier gas flow rate controller 51. Based on this data set, a calculation described later is performed, and the carrier gas flow rate controller 51 adjusts the carrier gas pressure. The flow rate of the carrier gas is changed by adjusting the valve 32.

  As shown in FIG. 2, the transport pipe 23 between the granular material on-off valve 24 and the lift tank 21 is branched so as to be connected to the first to fifth blower tuyere 11, and the five transport pipes 23. Is present in one granular material blowing facility 2, and a data set from five granular particle flow rate measuring devices 41 is sent to the carrier gas flow rate controller 51. As the carrier gas flow rate controller 51, for example, an arithmetic device such as a process computer can be used.

  Although the detailed illustration is omitted, FIG. 2 shows only one transport pipe 23 connected to the first blower tuyere 11a of the first group. A carrier gas pipe 31 for supplying a carrier gas 33 as shown in FIG. 2 is connected to each of the transport pipes 23 connected to the No. 5 blower tuyere 11 and blown into each of the blower tuyere 11. The flow rate of the granular material is controlled by changing the carrier gas flow rate. For simplification of the drawing, FIG. 2 shows a mode in which the blow pipe 22 is inserted only into the 1st and 21st ventilation tuyere 11, but in an actual blast furnace, 1 to 5 is shown. A blow pipe 22 to which a transport pipe 23 is connected is inserted into all the blower tuyere 11 of the number.

  In the carrier gas flow rate controller 51, the operations described in the following steps (1) to (3) are repeatedly performed, and the plurality of measured data sets described above are acquired, and based on the plurality of data sets. The flow rate of the granular material blown into each blower tuyere 11 is controlled by changing the flow rate of the carrier gas passing through each transport pipe 23 optimally every moment.

<Step (1)>
A data set of the flow rate of the granular material blown into each of the five blower tuyere 11 within a certain time and the carrier gas flow rate corresponding to the flow rate of the granular material is a granular material flow rate measuring device 41. N times. The plurality of measured data sets are sent from the granular material flow rate measuring device 41 to the carrier gas flow rate controller 51, and the carrier gas flow rate controller 51 averages the granular material flow rate measured at each measurement time mt. Is calculated.

  For example, at a certain measurement time mt1, the granular material flow rate measured at each of the five blower tuyere 11 is obtained, and one average value can be calculated from the measured five granular material flow rates. it can. Also, at the measurement time mt2 next to the measurement time mt1, one average value of the granular material flow rate measured at each of the five blower tuyere 11 can be calculated. Thus, the average value of the granular material flow rate at each measurement time mt is calculated. That is, the average value of the granular material flow rate is calculated corresponding to the number of times n.

  The number n is the number of times that the above-mentioned data set is measured within an appropriate period closest to the time t that determines the carrier gas flow rate. This n is a natural number of 3 or more, and it is preferable to measure the flow rate of the granular material and the flow rate of the carrier gas at the same time interval within the latest appropriate period. This is for correctly grasping the tendency between the carrier gas flow rate and the granular material flow rate described later.

<Step (2)>
Among the plurality of blower tuyere 11, a target blower tuyere 12 to be controlled for the powder flow rate is determined. In the following description, this target ventilation tuyere 12 is referred to as a first ventilation tuyere 11a. Next, the n average values of the granular material flow rates calculated in the step (1) are measured at the first ventilation tuyere 11a (target blowing tuyere 12) at each measurement time mt corresponding to the average value. The n deviations of the powder flow rate at the first blower tuyere 11a are calculated by subtracting from the n powder flow rates. Further, from the data set acquired in the step (1), n carrier gas flow rates corresponding to n powder flow rates, which are subtraction reductions for calculating the deviation, can be found.

  FIG. 3 is a graph showing the relationship between the carrier gas flow rate and the deviation of the granular material flow rate. In this graph, the horizontal axis X is the deviation of the granular material flow rate, and the vertical axis Y indicates the carrier gas flow rate. The relationship between the carrier gas flow rate at the first blower tuyere 11a and the deviation of the granular material flow rate at a certain time t after the measurement time mt is determined. For example, a relational expression (conversion expression) such as Y = aX + b is obtained by, for example, the least square method.

  In the example of FIG. 3, n is 20, and the average value of the powder flow rate measured at the five blower tuyere constituting the group is calculated, and the powder that becomes the subtraction reduction when calculating the deviation There are also 20 granular flow rates (20 granular flow rates measured at the first blower tuyere 11a). The deviation values (X-axis values) at each point in FIG. 3 are obtained by subtracting each of the 20 average values corresponding to each of the 20 powder flow rates. is there. The values of the carrier gas flow rate at each point in FIG. 3 (Y-axis values) are 20 carrier gas flow rates corresponding to the granular material flow rate, which is 20 subtractions.

  From the data in FIG. 3, the equation Y = −13.25X + 114.73 is obtained as a conversion equation. However, if the time t for determining the carrier gas flow rate changes, the data set at the measurement time mt also changes. This conversion formula is newly derived every time t.

<Step (3)>
In the relational expression obtained in the step (2), the deviation of the granular material flow rate becomes 0 (intercept in the conversion equation), that is, the carrier gas flow rate corresponding to the average value of the granular material flow rate is obtained. The carrier gas flow rate controller 51 adjusts the carrier gas pressure control valve 32 at the above-described time t, and sets the carrier gas flow rate so that the obtained carrier gas flow rate is obtained. Thus, based on the above-mentioned relational expression, the flow rate of the carrier gas blown into the target blower tuyere 12 (first blower tuyere 11a) at time t is sent. From the viewpoint of using the relational expression, it can be said that this relational expression is a conversion expression for converting the granular material flow rate (the value based on the X-axis deviation) into the carrier gas flow rate (the Y-axis value). .

  The time t for determining the carrier gas flow rate is set at regular intervals during the period when the powder is being sent to the blast furnace, that is, the steps (1) to (3) are appropriately performed at regular intervals during the period. Is preferred. Then, during that period, the carrier gas flow rate corresponding to the average value of the granular material flow rate is generally sent to the target blower tuyere 12.

  In the above description, the steps (2) and (3) have been performed with the target ventilation tuyere 12 as the first ventilation tuyere 11a. By performing the process, the flow rate of the carrier gas 33 is determined so that the average value of the flow rate of the granular material blown into each blower tuyere 11 is blown into all the blower tuyere 11. For this reason, it becomes possible to suppress the dispersion | variation in the flow volume of the granular material blown into all the ventilation tuyere 11 of No. 1-5 which comprises a 1st group. And if control of the flow volume of the granular material blown into the ventilation tuyere 11 of all the groups (the 1st-8th group) is performed for every group one by one, finally, all provided in the blast furnace 1 It is possible to suppress variation in the flow rate of the granular material blown into the blower tuyere 11.

  Moreover, in the said embodiment, the number of observation ventilation tuyere used as the basis which calculates the average value of a granular material flow volume is set to 5 which is the number of the 1st-5th ventilation tuyere 11 which comprises the 1st group. However, the number of observation blower tuyere in the present invention is not limited to this number. For example, all the ventilation tuyere 11 can be made into one group, and the number of observation ventilation tuyere can be made into the number of all the ventilation tuyere 11 substantially. For example, when all the ventilation tuyere 11 are made into one group and the number of observation blowing tuyere 11 is 40 blowing tuyere, there is an advantage that only one carrier gas flow rate controller 51 is required.

  In the prior art, in each of the transport pipe 23 and the blower tuyere 11, the operator sets the carrier gas flow rate corresponding to the flow rate of the target granular material to be blown to a predetermined value, and the set predetermined value and the powder The carrier gas flow rate was adjusted by adjusting the carrier gas pressure control valve 32 of each carrier gas pipe 31 so that the difference from the carrier gas flow rate measured by the granule flow rate measuring device 41 was zero.

  On the other hand, in the present invention, as described above, the deviation between the average of the flow rate of the granular material actually blown into the plurality of blower tuyere 11 and the flow rate of the granular material blown into the target blower tuyere. The carrier gas flow rate is determined so that becomes zero. For this reason, the flow rate of the carrier gas for sending the granular material at a constant flow rate is changed by momentarily changing the conditions in which the granular material 25 flows through them, such as the fluid resistance in the transport pipe 23 and the blower tuyere 11. Even if it changes, conveying granular material 25 to blast furnace 1 with carrier gas so that the flow volume of the granular material to blow may become the average of the flow volume of the granular material blown into a plurality of ventilation tuyere 11 Can do. And all the ventilation tuyere 11 is made into the target ventilation tuyere 12, and the calculation of process (1)-(3) is performed, and the dispersion | variation in the flow volume of the granular material injected into all the ventilation tuyere 11 is suppressed. It becomes possible.

  Blast furnace operation was performed using the blast furnace 1 and the granular material blowing equipment 2 shown in FIGS. In this blast furnace operation, the carrier gas flow rate controller 51 that performs the operations of the above steps (1) to (3) from time to time is operated, and the carrier gas flow rate is changed optimally, so that the granular material flow rate to the blast furnace 1 is increased. Was controlled (invention example). In the example of the present invention, pulverized coal is used as the powder, and the initial condition of the flow rate of the pulverized coal blown into each blower tuyere 11 is set to 1.6 t (tons) / h (hours). Blast furnace 1 was operated. In addition, let the target ventilation tuyere in process (2)-(3) be all the ventilation tuyere 11 which comprises the 1st group to 1-5.

  On the other hand, the conventional blast furnace operation was performed using the blast furnace 1 and the granular material injection | pouring equipment 2 shown in FIG.1 and FIG.2 (comparative example). In the comparative example, in each of the transport pipe 23 and the blower tuyere 11, the operator sets the carrier gas flow rate according to the target flow rate of the pulverized coal to be blown to a predetermined value, the set predetermined value, The carrier gas flow rate is adjusted by adjusting the carrier gas pressure control valve 32 of each carrier gas pipe 31 so that the difference between the carrier gas flow rate measured by the powder flow meter 41 and the carrier gas 33 is zero. In addition, the blast furnace 1 was operated under the same conditions as in the example of the present invention except that the carrier gas pressure control valve 32 was controlled every moment.

<Evaluation of Invention Examples and Comparative Examples>
FIG. 4 is a graph showing changes over time in the flow rate of pulverized coal blown into each blower tuyere in a comparative example. In this graph, the pulverized coal flow rate of the first to fifth blower tuyere 11 constituting the first group is shown. Regarding the time on the horizontal axis, 0, which is the origin, is expected that the flow rate of pulverized coal blown into each blower tuyere will be constant (steady state) when 10 minutes have passed since it was blown, but it exceeds 10 minutes. The horizontal axis represents 0 when 20 minutes have elapsed since the pulverized coal was blown.

  In the graph of FIG. 4, the flow rate of pulverized coal blown into the second blower tuyere 11 is the largest, and the flow rate of pulverized coal blown into the first blower tuyere 11 is the smallest. As time passed, the difference in the flow rate of pulverized coal blown into the first and second blowing tuyere 11 was about 0.68 t / h as shown in FIG.

  FIG. 5 is a graph showing the change over time of the flow rate of pulverized coal blown into each blower tuyere in the present invention example. The average flow rate of the pulverized coal flow rate in FIG. 5 is an average value of the pulverized coal flow rate of the first to fifth blower tuyere 11 calculated in the step (1). Regarding the time on the horizontal axis, similarly to FIG. 4, the time when 20 minutes have passed since blowing is set to 0 on the horizontal axis. When looking at the graph of FIG. 5, the pulverized coal flow rate is not significantly changed in the first to fifth blast tuyere 11, but the pulverized coal blown into the second blast tuyere 11 is the same as in FIG. 4. The flow rate is the highest, and the flow rate of the pulverized coal blown into the first blower tuyere 11 is the lowest. The deviation of the flow rate of the pulverized coal blown into these blower tuyere 11 was about 0.3 (t / h) as shown in FIG.

  As can be seen from the comparison between FIG. 4 and FIG. 5, the present invention was able to suppress variation in the flow rate of pulverized coal blown into each blower tuyere (transport pipe) for a long time (about 1500 minutes) in blast furnace operation. I understand.

  Further, in the comparative example, the reducing material ratio was 494 (kg / t-pig), while in the present invention example, not only the first to fifth ventilation tuyere 11 but also all the blowing tuyere 11. The flow rate of pulverized coal was controlled. Thereby, the reducing material ratio became 493 (kg / t-pig). For this reason, it turns out that the reducing material ratio could be reduced by this invention.

  According to the present invention, since the flow rate of the pulverized coal in all the blower tuyere 11 can be made the same, the temperature at the tuyere tip on the inner side of each blower tuyere becomes constant, and the iron ore raw material is reduced in all the tuyere tips. It can also be seen that the reaction can be promoted uniformly and deterioration of the furnace core air permeability and liquid permeability and furnace core inactivation can be suppressed.

DESCRIPTION OF SYMBOLS 1 Blast furnace 2 Granule blowing equipment 11 Blower tuyere 11a 1st ventilated tuyere 11b 2nd ventilated tuyere 11c 3rd ventilated tuyere 12 Target blower tuyere 13 Outlet 21 Lift tank 22 Blow pipe 23 Transport pipe 24 Powder Granule Open / Close Valve 25 Granule 26 Pressurizing Means 31 Carrier Gas Pipe 32 Carrier Gas Pressure Control Valve 33 Carrier Gas 34 Pressurizing Means 41 Granule Flow Rate Measuring Instrument 51 Carrier Gas Flow Controller

Claims (1)

It is a powder flow rate control method in a blast furnace that conveys powder particles to a plurality of blower tuyere with a carrier gas and blows the powder particles from the plurality of blower tuyere into a blast furnace,
Within a certain period of time, the flow rate of the granular material blown into each of the plurality of blower tuyere, and the carrier gas flow rate corresponding to the flow rate of the granular material are measured a plurality of times,
The average value of the plurality of granular material flow rates measured at each measurement time mt is subtracted from the granular material flow rate measured at each measurement time mt at the target blower tuyere among the plurality of blower tuyere. Obtaining a relational expression between a plurality of powder flow rates obtained by the above and a plurality of carrier gas flow rates corresponding to a powder flow rate that is a subtraction subtraction for calculating the deviation,
Based on the relational expression, the flow rate of the carrier gas to the target blower tuyere is determined so that the flow rate of the granular material blown into the target blower tuyere at the time t becomes the average value. Method for controlling the flow rate of granular material in

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