JPH11117008A - Bell type blast furnace charging method - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To reduce the O / C in a wide range from the middle part of the blast furnace to the center part of the furnace with the existing bell-type charging device,
Continue stable operation even during / C operation. SOLUTION: When ore and coke are charged as one charge and charged with each other alternately to perform a blast furnace operation, the ore and coke are each divided into two, and the divided ores 1O, 2
This is a bell-type blast furnace charging method in which O and coke 1C, 2C are sequentially charged, respectively, and after charging the first ore 1O divided every 5 to 30 charges, the coke 3C is placed in the furnace radially intermediate portion. The remaining ore 2 charged and then divided
O is charged into the furnace wall.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bell type blast furnace charging method.

[0002]

2. Description of the Related Art In the operation of a blast furnace, it is important to maintain the ore weight / coke weight (hereinafter, referred to as O / C) in the furnace radial direction and to control the shape of the cohesive zone for stable operation. It has been. In recent years, a large amount of pulverized coal has been blown from a blowing tuyere at the bottom of a furnace. For this reason, the O / C in the blast furnace becomes high, which is one of the causes of inhibiting the air permeability. In particular, a decrease in air permeability at the center of the blast furnace poses a problem for stable blast furnace operation. For this reason, various attempts have been made in the past to reduce the O / C at the center of the furnace. For example, Japanese Unexamined Patent Publication No.
No. 8, as disclosed in the publication, a method of directly charging a mixture of ore and coke into the center of the furnace with a charging chute or the like separately provided without using a bell-type or bell-less type charging device. is there. Further, as disclosed in Japanese Patent Application Laid-Open No. 62-290809, there is a method of charging coke into the center of the furnace using a bell-less charging device (specifically, a rotating chute).

[0003]

However, Japanese Patent Application Laid-Open Publication No.
In the method of JP-A-290708, a separately provided charging device is required, so that the equipment becomes expensive and the O / C can be adjusted only in a narrow range at the center of the furnace. Was. Further, in the method disclosed in Japanese Patent Application Laid-Open No. 62-290809, an extremely low O / C region is formed at the center of the furnace, and the middle portion in the radial direction of the furnace (hereinafter referred to as the middle portion in the furnace) has a high O / C.
/ C, there is a problem that causes shaft pressure fluctuation. The present invention aims to reduce the O / C in a wide range from the middle part in the furnace to the center part in the furnace by using the existing bell-type charging apparatus, and to increase the O / C.
It is an object to continue stable operation even during / C operation.

[0004]

Means for Solving the Problems The present invention has been made to solve the above-mentioned problems, and the means 1 performs blast furnace operation by alternately charging ore and coke as one charge. At this time, the ore and coke are each divided into two, a bell type blast furnace charging method of sequentially charging the divided ore and coke, respectively, after charging the first ore divided for each predetermined charge, In this method, coke is charged at a radially intermediate portion in the furnace, and then the remaining ore is charged into the furnace wall. Also,
Means 2 is that the predetermined charge described in Means 1 is set at an interval of 5 to 30 charges. In addition, the said furnace wall part,
As shown in FIG. 1, a portion of the furnace opening at a range of 5 to 10% of the furnace radius in the furnace radial direction from the furnace wall, and the furnace center portion is 5 mm from the furnace center in the furnace radial direction. It is a portion in the range of 10% to 10%. Also, the middle part in the furnace radial direction (middle part in the furnace)
Means the remaining portion sandwiched between the furnace wall and the center of the furnace.

[0005] As shown in FIG. 2, the coke divided into two parts, 1C (the first batch of coke, hereinafter referred to as 1C) and 2C (the second batch of coke, hereinafter referred to as 2C), are divided into two parts. In a four-batch charge of successively charged ores 1O (first batch ore, hereinafter referred to as 1O) and 2O (second batch ore, hereinafter referred to as 2O), high O / C, that is, Due to the increase in the amount of ore charged in 1O and 2O, those deposited on the furnace wall and in-furnace intermediate portion of 2C charged before 1O are flushed to the center of the furnace and flow to the center of the furnace. A mixed layer of coke and ore is formed, and the charged 10 is deposited from the furnace wall to an intermediate part in the furnace.
As a result, the amount of coke in the middle part of the furnace decreases and the amount of ore increases, so that the permeability in the middle part of the furnace deteriorates. Then, when 2O is charged next, a large amount of the 2O flows from the middle part in the furnace to the center part in the furnace due to the influence of 1O deposited on the furnace wall. If this phenomenon continues for a long time, the O / C from the middle part in the furnace to the central part in the furnace becomes high, and the reducing gas flow rising in the furnace tends to flow around, and the shaft pressure tends to fluctuate. In the present invention, coke is charged into the middle part of the furnace in order to reduce the high O / C from the middle part in the furnace to the center part of the furnace. That is, after charging 1O, which is the ore of the first batch that has been divided, coke 3
C (hereinafter referred to as 3C), coke is deposited on the portion, and then the ore of the ore of the remaining divided batch is charged, so that the charged 2O is intermediate in the furnace. Since the amount of the 2O flowing toward the center of the furnace is suppressed by colliding with the 3C deposited in the furnace and the 3C is charged from the middle part of the furnace to the center part of the furnace as described above, the furnace O / C in the central portion of the furnace is reduced from the inner intermediate portion, and the air permeability in that portion is improved. In addition, each charge 1C, 2C, 1
When 5 batches of O, 3C and 2O were charged, 1
Even when compared with the case where 5 to 30 charges are charged for 4 batches of C, 2C, 10 and 2O and then 1 charge for the 5 batches is repeated, the air permeability improvement effect is substantially the same. On the other hand, if the 5-batch charging is performed every charge, the productivity is reduced.
It is preferable to carry out the process at 0 charge intervals.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention
It described in example using a 00m ³ grade large bell-type blast furnace. For 4 batch charging of 1C, 2C, 10 and 20, 1
C is inserted into the furnace wall near the middle of the furnace using removable armor (hereinafter referred to as MA), and 2C is also mounted on the furnace wall near the middle of the furnace using MA in the same way as 1C. To charge.
After charging 1C and 2C, 1O is charged into the furnace wall without using MA, and 2O is also charged into the furnace wall without using MA like 1O. After repeating this 4-batch charging from 5 to 30 charges, 1C and 2C are charged into the furnace wall near the middle part of the furnace using MA, and 1O is not used on the furnace wall without using MA. After that, 3C is charged into the middle part of the furnace using MA. Then, as in 1O, 2O is charged into the furnace wall without using MA. FIG. 1 shows the state of deposition of the charged materials in the blast furnace after the charging of the five batches.

[0007]

EXAMPLES Tables 1 and 2 show a comparative example in which four batches of 1C, 2C, 10 and 20 were repeatedly charged, and 1 in the same manner as the comparative example.
An example of the present invention is shown in which four batches of C, 2C, 10 and 20 are charged for 10 charges, and 5 batches of 1C, 2C, 1O, 3C and 2O are charged for 1 charge. Things. And Table 1 shows the operating conditions of both examples,
Table 2 shows the operation results at that time.

[0008]

[Table 1]

[0009]

[Table 2]

As can be seen from Table 1, when 5 batches are charged every 10 charges, the total coke amount of the batch increases compared to when 4 batches are charged. The operation was carried out by increasing the amount of ore of 10 and 20 so as to approach O / C. As a result, in this embodiment, as can be seen from FIG. 3, the gas temperature distribution in the radial direction in the furnace is higher than that in the comparative example, the temperature in the furnace center from the middle of the furnace is increased, and the gas temperature in the furnace wall is increased. Is suppressed. Therefore, as can be seen from Table 2, the number of shaft pressure fluctuations was reduced, and the furnace body heat load was reduced. Further, in this example, due to the ventilation improvement effect, S in the hot metal was reduced, and the quality of the hot metal was improved.

[0011]

According to the bell type blast furnace charging method according to the first and second aspects, (1) the O / C from the radially intermediate portion in the furnace to the central portion in the furnace can be properly adjusted without major equipment modification. Can be maintained. (2) A stable operation can be continued even during a high O / C operation such as a large amount pulverized coal injection operation. (3) Since the number of shaft pressure fluctuations is drastically reduced and the furnace condition is stabilized, it is possible to increase the amount of tapping, reduce the heat load of the furnace body, and extend the life of the furnace body. And so on.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of ore and coke deposition in a blast furnace according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of ore and coke deposition in a furnace when four batches of charging are continued.

FIG. 3 is a diagram showing a gas temperature distribution at a position in a furnace radial direction.

[Description of sign]

1C 1st batch coke 2C 2nd batch coke 3C coke 1O 1st batch ore 2O 2nd batch ore

Claims (2)

[Claims] A ore and coke are charged as one charge, and the ore and coke are charged alternately to perform a blast furnace operation. The ore and coke are each divided into two parts, and the ore and coke thus divided are charged sequentially. A blast furnace charging method, comprising: charging the first ore divided for each predetermined charge, charging coke to a radially intermediate portion in the furnace, and then charging the remaining ore for the furnace wall. A bell-type blast furnace charging method, which comprises charging a blast furnace. 2. The method for charging a bell-type blast furnace according to claim 1, wherein the predetermined charge is 5 to 30 charge intervals.