JPS5943803A - Charging method of raw material to bell type blast furnace - Google Patents

Abstract

PURPOSE:To make the charging of raw materials into a furnace as uniform as possible and to maintain stable iron making operation by supplying the next raw material in a slightly larger amt. in the place where the deposition of the raw material is smallest in the circumferential direction on a large bell. CONSTITUTION:Deposition detectors 12 are provided in, for example, 4-6 positions spaced at an equal angle in the circumferential direction inside of a large bell hopper 4, and the deposition of the raw material 11b in the circumferential direction on a large ball 2 is detected with said detectors. A comparing calculator compares and calculates the values detected by the detectors and outputs the signal (defined as L) for assigning the position where the deposition of the raw material 11b in the circumferential direction is smallest. On the other hand, a turning chute 6 is rotated and its port position is detected by the detectors. A signal for commanding the opening of the gate 8 of a stationary hopper 9 is outputted from a controller slightly before the time when the detection signal coincides with the signal L. The gate 8 is then opened, and the discharge of the raw material 11 is begun with a chute 6 onto the small bell 5 corresponding to the place where the deposition of the material 11b is smallest.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for charging raw materials into a bell blast furnace.

Figure 1 schematically shows the top of a bell-type blast furnace, in which 1 is the blast furnace body, 2 is a large bell, 3 is a large bell cup, 4 is a large bell hopper, 5 is a small bell, and 6 is a rotating shaft. Chute, 7 is a fixed chute, 8 is a hopper gate, 9 is a fixed hopper at the top of the furnace, 10 is a hanging rond for large and small bells, 11 is raw material in fixed hopper 9, 11 a is raw material on small bell 5, 1
1b is the raw material on the large bell 2.

In order to maintain stable ironmaking operations in a bell-type blast furnace like the one shown in Figure 1, it is essential to make the charging distribution of Nochiri ξ・1 uniform in the furnace. This is a matter.

For that, the original to the big bell 2, l:'l + +
Although it is essential to make the distribution of b uniform, a uniform distribution has not yet been obtained.

The distribution of the raw material 11b on the large bell 2 is uneven.
1 is discharged onto the large bell 2 via the fixed chute 7, the rotating chute 6, and the small bell 5, the opening timing of the gate 8 in the fixed hopper 9 and the boat position in the rotating chute 6 are completely unrelated. Therefore, the circumference on the small bell 5 is The raw material 11a is segregated in the direction, and the raw material 11a on the small bell 5 is
The segregation of a causes the reconnaissance (non-uniform distribution) of the raw material 11b onto the large bell 2.

In addition, when the present inventor investigated the segregation state of the raw material 11a in the circumferential direction on the small bell 5, it was found that the weight of the raw material 11a was large on the small bell 5 near the raw material discharge start point, and the raw material discharge was completed. Raw material 11 is placed on the small bell 5 near the point.
It was found that the amount of a deposited was small.

The segregation of the original 11Elila on the small bell 5 is slightly alleviated on the large bell 2 in the lower stage, but the large bell 2
The upper raw material 1111 is still sedated and is charged into the furnace in that state.

If the segregation charging of the raw material 11b into the furnace continues indefinitely, there will be a difference in air permeability and reducibility in the furnace, and the tapping temperature and S
This causes variations in t I S A'F, making it difficult to maintain stable operation and causing an increase in the fuel ratio.

In view of the above-mentioned conventional problems, the present invention is designed to charge raw materials into a furnace as uniformly as possible, and an example of its implementation will be described below with reference to the drawings.

As shown in FIG. 1, deposit amount detectors 12 such as a sounding device or a microwave profile meter are installed at equal angular intervals in the circumferential direction of the large bell hopper 4, for example, at locations 4 to 6@, and each Deposition! The detector 12 detects the amount of raw material ii b deposited on the large bell 2 in the circumferential direction.

As shown in FIG.
The comparison table 1f calculator 13 outputs a position designation signal for the location where the accumulation zone of the raw material 1'ib in the upper circumferential direction is the least.

On the other hand, the rotating chute 6 is rotated by, for example, 10 r, p, m, and its port position is detected, for example, every 30 degrees by an arbitrary position detector 51, and this port position detection signal and the comparison calculator 13 The minimum accumulation amount position designation signal and the time difference setting value are inputted to the controller 14 as shown in FIG. In other words, when the port of the rotating chute 6 corresponds to a position 60° in front of the point on the large bell 2 where the sedimentation of the raw material 11b is least, the controller 14 also sends a command signal to open the gate 8 in the fixed hopper 9. is output, the gate 8 is opened by this opening command signal, and the raw material 11 on the large bell 2 is opened.
The raw material 11 in the fixed hopper 9 is started to be discharged via the rotating chute 6 onto the small bell 5 corresponding to the location where the amount of accumulation of b is the smallest.

Hiko, the time difference setting value is the gate 8 of the fixed hopper 9.
Since there is a time lag between when the raw material 11b is opened and when the raw material 11 in the fixed hopper 9 is discharged through the port of the rotating chute 6 to the small bell 5, the amount of the raw material 11b deposited on the large bell 2 is the lowest. This is necessary for moving the raw material 11 in the fixed hopper 9 onto the small bell 5 corresponding to 1 second before the match,
Although the gate 8 of the fixed hopper 9 is opened, it is better to set it to an appropriate value depending on the blast furnace.

Furthermore, if the deposition amount detector 12 is installed at more locations, it is possible to accurately detect the segregation state of the raw material 1.1b in the circumferential direction on the large bell 2, but for practical purposes, 4 to 6 locations are sufficient. It is not possible to detect the state of segregation at less than 3 places because it becomes difficult to detect the state of segregation.

Furthermore, the gate 8 of the fixed hopper 9 is closed after a preset timer/J count from the charged amount (time required for complete discharge, 1: after 1 to 2 seconds).

As mentioned above, according to the method of the present invention, the next raw material can be supplied many times to the concave area on the large bell where the amount of raw material deposited is the least, so that raw ore is charged almost uniformly into the furnace. -Therefore, variations in the tap temperature, iron content, Si, etc. are reduced, making it possible to maintain stable ironmaking operations.

FIG. 3 shows a comparison of variations in hot metal temperature and Si in the pig iron between the conventional raw material charging method and the raw material charging method of the present invention.

It can be seen that according to the raw material charging method of the present invention, the variation in hot metal temperature and Si in the pig iron is smaller than the conventional raw material charging method, and stable pig iron making operation is maintained.

[Brief explanation of drawings]

@Figure 1 is a schematic diagram of the top of a bell-type blast furnace to which the method of the present invention is applied, Figure 2 is a block diagram showing an example of a gate opening control circuit for a hopper fixed at the top of the furnace, and Figure 3 is a diagram showing the conventional material charging method and Hot metal temperature and S in pig iron in the raw material charging method of the present invention
It is a comparison graph showing the variation of i. Applicant Kawasaki Steel Corporation Figure 1

Claims (1)

[Claims] In addition to detecting the minimum amount of raw material deposited in the circumferential direction on the large bell, the port position of the rotating chute is also detected, and the minimum amount of raw material deposited is detected at the required time before the detected position of the boat coincides with the detected position of the boat. A method for charging raw materials into a bell-type blast furnace characterized by controlling the opening of a gate of a hopper fixed at the top of the furnace and discharging the next raw material onto a small bell.