JP3228083B2 - Blast furnace interior interior tracking method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for tracking a blast furnace furnace internal charge, which enables highly accurate residual iron and residue management.

[0002]

2. Description of the Related Art In blast furnace operation, pig iron and slag produced in the furnace are accumulated in the hearth one after another, so that the slag or tap hole is opened at an appropriate time and discharged out of the furnace. Work is repeated. However, the slag accumulated on the pig iron in the hearth has a very high viscosity as compared with the pig iron, so that the slag is often not sufficiently discharged even by the discharging operation. Then, when the operation of closing the tap hole or tap hole and continuing strengthening while the slag remains in the furnace is repeated as described above, the slag level of the hearth gradually increases, and this This may lead to furnace conditions such as hanging, which may lead to reduced production. Therefore, the slag accumulated in the hearth of the blast furnace must be discharged as completely as possible every time the slag is discharged, and care must be taken so that the slag level in the hearth does not become too high.

[0003] On the other hand, in recent years, with the increase in size and efficiency of blast furnaces, the method of performing slag using only tapholes has become widespread. Particular attention should be paid to the kinematic viscosity of pig iron, which is very high (about 100 times higher), so that the slag discharge using only tapholes tends to be more inefficient. There is a need.

In view of the above, conventionally, the "actual tapping amount and slag amount (measured with a load cell type weighing machine or the like)" and the "calculated tapping amount and slag amount" have been conventionally calculated from the " Operation has been performed while estimating the amount of residual iron and the amount of residue.

In this method, a predetermined number of "minimum unit charges (generally, a batch or a batch of batches, which are selected for the operation management of a blast furnace) are always contained in a blast furnace. However, hereafter, each time one charge is charged into the furnace, it is said that one charge has been charged in the furnace. "The oldest charge that was present (the charge in the bottom layer of the furnace) was discharged out of the furnace." The amount of residual iron and the amount of residue in the furnace were estimated from "the amount of slag" and "the actual amount of slag and the amount of actual slag".
That is, in the past, the amount of residual iron and the amount of residue in the furnace were estimated on the premise of the concept that "one charge is always discharged when one charge is charged".

However, in reality, the scale-reducing operation (FIG. 1)
As shown in the figure, the furnace charging is stopped or the charging interval is lengthened, as in the case of the operation in which the amount of furnace interior is reduced compared to the normal operation, or when there is a calm. In some cases, the level of the charge inside the furnace is reduced, and therefore, the above-mentioned assumption that "there is always a predetermined number of charges in the furnace" does not fit the actual situation. Further, the same amount of charge is not always loaded every time, and for example, as shown in FIG. 2, the discharged amount (A) may be smaller than the actually charged amount (D). That is, computationally, tea present in the bottom of the furnace - May have for example _^1/2 di volumes also "1 Cha - - volume of di is Cha charged to new furnace di instrumentation If "one charge is discharged when the gas enters," the mass balance in the furnace (the difference between the charged volume and the discharged volume) is not faithfully reproduced. Therefore, it was thought that controlling the discharge of hot metal and slag based on this concept was one of the causes of instability of blast furnace operation and malfunction of the furnace condition.

[0007] In view of the above, an object of the present invention is to provide a furnace interior charge capable of more accurately estimating the amount of residual iron and the amount of residue in a blast furnace performed for each tapping. Was to establish a tracking method.

[0008]

SUMMARY OF THE INVENTION The present invention has been completed based on the results of studies conducted by the present inventors, etc., which have been earnestly conducted to achieve the above object. When the raw materials are charged into the blast furnace, the “charge level” immediately after the charging is measured each time the charging of the minimum unit of management is completed, and the level is transferred to the furnace. After calculating the total volume (actual volume value) of the existing charge and the theoretical volume value of the charge present in the furnace at that time, the difference between the actual volume value and the theoretical volume value (actual volume value) Volume value-theoretical volume value)
If this value is negative, the charge present in the furnace is discharged out of the furnace sequentially from the oldest one by the minimum unit until the value turns positive. That the blast furnace operation can be performed accurately and stably by adopting the method that
"In the above method, when calculating the theoretical volume of the charge present in the furnace, a volume conversion coefficient in the solid-liquid mixed state and a volume conversion coefficient in the solid state are set, and the minimum unit for management existing in the furnace Of the charged materials, the volume is converted based on the volume conversion coefficient in the solid-liquid mixed state from the oldest one, and integrated, and the integrated value is “prepared by analyzing the conditions inside the furnace in advance. From the time when the volume value of the solid-liquid mixed charge calculated based on the model was exceeded ”, this time, volume conversion is performed based on the volume conversion coefficient in the solid state, and integration is further performed. And a stable blast furnace operation ".

[0009]

That is, according to the present invention, the actual volume value of the furnace interior material at the time when the charging of, for example, one charge is completed into the blast furnace which has been in operation has been completed is determined by a sounding level meter (furnace type furnace). At the same time, the theoretical volume value of the charge present in the furnace at each time is determined in each charge. The volume is calculated from the actual weighing results at the time of charging, and then the actual volume value and the theoretical volume value are compared in magnitude. When "actual volume value ≧ theoretical volume value", the charger is immediately inserted into the furnace interior. In this case, no charge is theoretically discharged outside the furnace. On the other hand, when “actual volume value <theoretical volume value”, the oldest charge existing in the furnace (the most Assuming that the lower charge is discharged outside the furnace, the furnace interior is tracked.

According to this method, since the blast furnace charge tracking is performed in consideration of the volume of the charge actually present in the furnace (based on the measured value of a sounding level meter or the like), the conventional method is used. Unlike the “method of estimating the amount of residual iron and slag in the blast furnace from“ the actual amount of slag and slag ”and the“ calculated amount of slag and slag ”, It becomes possible to manage the amount of tapping and slag that matches the operation.

At this time, the logical volume value of the charge is calculated by calculating the theoretical volume of each charge by converting the bulk density (m ³ / ton) from the actual charge value (ton) of each charge. However, in this case, "the bulk density conversion constant for the charge melted in the furnace to form a solid-liquid mixture" and "the bulk density conversion for the charge which remains as a solid" By setting two constants, "constant", and calculating the volume of the solid-liquid mixed charge and the volume of the solid charge, respectively, it is possible to obtain a theoretical volume value that better corresponds to the actual furnace conditions. Can be.

More specifically, first, from the “cohesive zone shape” obtained from the furnace condition model prepared by analyzing the condition inside the blast furnace in advance, of the charges existing in the furnace, Calculate the calculated volume of the charge that has melted into a solid-liquid mixture. Next, the actual volume value of the furnace interior charge is determined from the “furnace interior charge level measured by a sounding meter or the like”, and the difference between the actual volume value and the calculated volume of the solid-liquid mixed charge is calculated from the difference. Determine the volume of the solid charge. On the other hand, using the bulk density conversion constant, the theoretical volume in the case where each becomes a solid-liquid mixed state from the oldest charge existing in the furnace is determined. If the sum is equal to or greater than the amount of liquid charge calculated based on the model, the subsequent charge (the final volume of the theoretical volume in the case of a solid-liquid mixture in order) has been determined. From the upper charge of the charge) to the solid charge
The theoretical volume is determined by using the bulk density conversion constant for di, and the actual volume and the theoretical volume are compared. If such a second method is employed, as described above, it is possible to manage tapping and slag more appropriately in accordance with the actual furnace conditions.

The procedure for carrying out the present invention will be described below in the context of specific conditions set experimentally.

FIG. 3 is a flowchart showing the entire procedure for implementing the method of the present invention. In this example, the following preconditions (a) to (e) were set. (a) In order to facilitate verification, it is assumed that only one type of weighing setting exists in the furnace, and that the actual weighing value of each charge is 15 tons for coke and 60 tons for ore. Assume that the total is 75 tons. (b) Assume that the blast furnace main body has a column shape with a radius of 7 m and a height of 30 m. (c) Bulk density conversion constant for solid charge is coke:
0.5 ton / m ^3, ore: a 2 ton / m ^3, the solid-liquid mixture form Cha - bulk density conversion constant for di Koh - box: 0.5 ton / m ^3,
Ore: the 6ton / m ^3. (d) The volume of the solid-liquid mixed furnace interior charge determined from the “cohesive zone shape obtained from the model” shall be 320 m ³ . (e) At this point, it is calculated that there are 8 solid-liquid mixed charges and 42 solid charged charges in the blast furnace as shown in FIG. I do.

Now, from this state, it is assumed that a new charge having a weighing result of 25 tons for coke and 100 tons for ore is charged, and the level of the charge in the furnace by the sounding level meter at that time is changed. Assume that it was 18.6m from the furnace bottom.

Then, the actual total volume of the charged material in the furnace is calculated as “7 m × 7” based on the measured value of the sounding level meter.
m × π × 18.6 m ≒ 2862 m ³ ”. In addition, the calculated volume of the solid-liquid charge existing in the furnace is 300 m ^{3 when} calculated based on the model output, and this is the actual volume of the solid-liquid charge. Therefore, based on these, the actual volume of the solid JoSo container is "2862m ³ - 300m ³ = 2562
m ³ ”. FIG. 5 schematically shows the state of charging in the furnace at this time.

Here, when the mass balance of the solid charge is first calculated, the total theoretical volume of the solid charge after the latest charge is charged is calculated by weighing each charge. From the results: ｛15 (ton) /0.5 (ton / m ³ ) + 60 (ton) / 2 (ton /
m ³ )｝ × 42 + ｛25 (ton) /0.5 (ton / m ³ ) +100 (ton) /
To ^{2 (ton / m 3)}} = 2610m 3 becomes.

On the other hand, since the actual volume of the solid charge at this time is 2562 m ³ as described above, the theoretical volume is greater than the actual volume.
Considering that the fuse has melted, the "oldest solid charge" is set as the first in tracking, and the theoretical volume is sequentially reduced in the order of the next charge, the next charge, and so on.

At this time, if the theoretical volume of the "oldest solid charge" is first reduced, the theoretical volume of the solid-liquid mixed charge is integrated with the above-mentioned one charge. I do. Then, the volume of the solid-liquid mixed furnace interior charge is as follows. 320m ³ + ｛15 (ton) /0.5 (ton / m ³ ) +60 (ton) / 6 (t
on / m ³ ) = 360 m ³

Therefore, comparing the theoretical volume and the actual volume of the solid-liquid mixture charge, it is found that “theoretical volume> the actual volume” and “theoretical volume ≦ the actual volume” do not hold. Considering the balance, it is considered that the oldest charge of the solid-liquid mixed charge has been discharged out of the furnace, and the tracking reduces the theoretical volume from the oldest solid-liquid mixed charge.

In this case, the oldest solid-liquid mixed charge is 1
If the charge is discharged, the theoretical volume is 360 m ³ − ｛15 (ton) /0.5 (ton / m ³ ) +60 (ton) / 6 (t
on / m ³ ) = 320 m ³ , and “theoretical volume ≦ actual volume (300 m ³ )” has not been established yet. Therefore, if one charge is further discharged, the theoretical volume is 320 m ^3- ｛15 (ton) /0.5 (ton / m ³ ) +60 (ton) / 6 (t
on / m ³ ) = 280 m ³ , thus satisfying “theoretical volume ≦ actual volume”.

In other words, in this example of the method, in addition to the one existing in the furnace, a new charge having a weighing result of 25 tons for coke and 100 tons for ore is charged. Are each charged into the furnace until it is charged.
This is equivalent to a charge approximately 1.6 times that of di (cokes: 15 tons, ore: 60 tons). Therefore, in this example, the charge (copper) is about 1.6 times that of each charge (coke: 15 ton, ore: 60 ton) which was charged in the furnace until the latest charge was charged. -25 tons, ore: 100 tons), it is possible to grasp that two charges were finally discharged outside the furnace.

As described above, the actual state cannot be grasped by the conventional simple tracking that "one charge is always discharged to the outside of the furnace when one charge is performed". In the method according to the present invention, which performs tracking in consideration of the volume of the existing charge (based on the measurement value of the sounding level meter), it is possible to grasp the actual situation accurately.

Therefore, by applying the method of the present invention to an actual furnace, not only during steady operation, but also during unsteady operation such as reduced-scale operation, tracking of the charge accurately reflecting the conditions in the furnace. It is possible to accurately manage the residual iron and the residue even during the unsteady operation.

[0024]

[Summary of effects] As described above, according to the present invention, it is possible to more accurately estimate the amount of residual iron and the amount of residue in the blast furnace performed for each tapping, and a proper and stable blast furnace operation can be performed. Industrially useful effects, such as being possible, are brought about.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram relating to a reduced-scale operation of a blast furnace.

FIG. 2 is an explanatory diagram of a blast furnace operation example in which the charging amount and the discharging amount are different.

FIG. 3 is a flowchart showing the concept of the charged object tracking according to the present invention.

FIG. 4 is a schematic diagram for explaining an example of a situation of an initial blast furnace interior charging when practicing the present invention.

FIG. 5 is a schematic diagram illustrating an example of a situation of a blast furnace interior charging when charging one charge with an increased charge amount.

Continuation of front page (72) Inventor Tsuneji Masamori 1850 Minato, Wakayama-shi, Wakayama Sumitomo Metal Industries, Ltd. Wakayama Works (56) References JP-A-51-8710 (JP, A) JP-A-8-176622 (JP, A) JP-A-53-117616 (JP, A) JP-B-55-9441 (JP, B2) JP-B-62-60442 (JP, B2) (58) Fields investigated (Int. Cl. ⁷⁾ , DB name) C21B 5/00 311

Claims (2)

(57) [Claims] 1. When charging a raw material into a blast furnace, every time charging of a minimum unit of charge in the management is completed, a “charge level” immediately after charging is measured, and the level is measured. And the total volume of the charge present in the furnace (actual volume value)
After calculating the theoretical volume value of the charge present in the furnace at that time, the difference between the actual volume value and the theoretical volume value (real volume value-theoretical volume value) was calculated, and this value was negative. In this case, the blast furnace operation is performed assuming that the charge present in the furnace has been discharged out of the furnace sequentially from the oldest one by the minimum unit by the amount until the value is converted to a positive value. Blast furnace furnace interior material tracking method. 2. A method for determining a theoretical volume of a charge present in a furnace, wherein a volume conversion coefficient in a solid-liquid mixed state and a volume conversion coefficient in a solid state are provided, and a minimum unit for management existing in the furnace. Of the charged materials, the volume conversion is performed based on the volume conversion coefficient in the solid-liquid mixed state in order from the oldest one, and the integration is performed. From the time when the volume value of the solid-liquid mixed charge calculated based on the model is exceeded, and then perform volume conversion based on the volume conversion coefficient in the solid state and integrate. The blast furnace furnace interior material tracking method according to claim 1.