JPH0128086B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a charging method for a bell-less blast furnace, and more specifically, a method for charging raw materials into a blast furnace using a bell-less charging device such that the raw materials are placed within a desired angular range in the circumferential direction. This relates to a charging method suitable for charging only.

In blast furnaces, instead of the method of charging the charge into the furnace by opening and closing a large bell and a small bell, in recent years, instead of using a large bell or a small bell, the charge has been transferred through a distribution chute with a tilting and rotating mechanism. A so-called bellless type furnace top charging device, which distributes charging into the furnace, has come into widespread use.

As shown in Fig. 1, this bell-less type furnace top charging device transfers the charge from the belt conveyor 1 of the blast furnace through a switching chute 2, an upper gate valve 3, and an upper seal valve 4 to the raw material provided at the top of the furnace. Once stored in the storage hopper 5, when the charge in the furnace is unloaded and reaches the level of a predetermined stock line 6 to be replenished, a lower gate valve or control for adjusting the charge flow rate is activated. The gate valve 7 and lower seal valve 8 are opened to supply the charge in the raw material storage hopper 5 to the distribution chute 9, and the rotation speed and inclination angle of the distribution chute are adjusted to sequentially supply the charge. The material is continuously distributed and charged into the furnace 10 from the distribution chute 9.

By the way, the furnace wall bricks of the blast furnace are not worn out when fired, so the inclination angle and number of turns of the distribution chute may be selected so as to uniformly distribute the charge in the circumferential direction. However, as years pass after operation, the wear and tear of the furnace wall bricks at specific positions in the circumferential direction becomes significant, and in severe cases, most of the furnace wall bricks may be worn out, causing the iron shell to become red-hot. In this case, deposits may be formed on the blast furnace shaft at specific circumferential locations where the gas flow within the furnace is obstructed, causing irregularities in the descent of the charge into the furnace.

If such a situation occurs, in the conventional method using a bell-type charging device, it is difficult to control the distribution of the charge in the radial direction by operating the movable armor in a specific direction, or to change the tuyere diameter in a specific direction. Efforts have been made to correct the non-uniformity in the circumferential direction by controlling the amount of air blown, but these efforts have not been sufficiently effective.

On the other hand, in the conventional method using a bellless charging device, the circumferential position in the furnace where charging is required, for example, the circumferential angular range that narrows the diagonally shaded area a in the N direction in Figure 2, for example, the angle θ. The distribution chute was rotated back and forth between the two, and ore or coke was charged centrally at that position. However, in this method, the motor for driving the distribution chute alternately repeats startup, low speed, high speed, deceleration, and stop operations in the forward and reverse rotation directions, as shown in Figure 3, so the motor is overloaded. In addition to the disadvantages of increased power consumption and increased power consumption, the motor requires time to slow down, decelerate, and stop, during which time the distribution chute pivots and the charging angle range becomes wider than necessary (e.g. There is a drawback that the angle θ' in Fig. 2).

The object of the present invention is to provide a charging method that eliminates the above-mentioned drawbacks of the charging method using a bellless charging device.

The charging method for a bellless blast furnace according to the present invention is characterized in that a distribution chute provided at the bottom of a raw material storage hopper at the top of the blast furnace is rotated in a constant direction at a desired speed; The purpose of the present invention is to open or close a control gate valve provided between the hopper and the distribution chute only while the device is swinging between the angular ranges set in the hopper and the distribution chute.

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 4, a device for carrying out the charging method according to the invention is schematically shown. In the same figure, reference numbers 1 to 10 are the same as the constituent parts shown in FIG. 1, so their explanation will be omitted. 11 is a detector attached to the pivot shaft of the distribution chute and detects the angle in the circumferential direction of the chute, 12 is a comparator, 13 is a setting device, 14 is a control device, and 15 is a valve opening/closing drive for the control gate valve. It is a mechanism.

In the apparatus configured as described above, first, the locations in the furnace where charging is required and the required charging amount are checked in advance using a known device, and the circumferential position and range as well as the required charging amount are set in the setting device 13. The distribution chute 9 is rotated in a fixed direction at a predetermined speed by a known drive mechanism (not shown).

Under such conditions, when the distribution chute 9 turns within the range set in the setting device 13, for example within the range of angle θ in the N direction in FIG. Then, the control gate valve 7 is opened, and the ore or coke in the hopper 5 is charged to the required location in the furnace via the distribution chute 9. Then, such charging of ore or coke is performed several times in succession for each rotation of the distribution chute 9. When the charging positions are distributed in the radial direction of the blast furnace, the inclination angle α of the distribution chute 9 is changed every rotation or every predetermined number of rotations. The required number of times of charging can be easily determined from the amount of charging possible by opening the valve once and the required amount of charging.

It should be noted that a known level meter may be used to detect whether ore or coke has reached a desired level after charging.

Next, we will discuss the case where a full-scale cold model was created outside the reactor and a charge distribution test was conducted.
Assuming that the iron shell is red-hot in the X direction of Figure 5, the necessary range for charging ore to protect the iron shell.
The angle θ ₁ of PQ⌒ is determined in advance, and the angle (LSOP) θ ₂ from the reference line OS to the position P is determined. Then, set these angles θ ₁ , θ ₂ and the required charging amount using the setting device 13.
When charging was performed using the method according to the present invention with the setting set to .theta., the angle was _.theta.3 , and the charging was performed in the state shown by the solid lines in FIGS. 6A to 6C.

On the other hand, the charging range using the conventional method was θ ₄ , which was a 40% increase compared to θ ₃ . For this reason, not only is the overall charging height _h2 lower than the charging height _h1 in the case of the charging method of the present invention (when the charging amount is the same), but also As shown by the broken lines in A to C, the charging height at the center became lower than the charging height at both ends (because the speed of the chute decreased at both ends).

As is clear from the above-mentioned model examples, the charging method of the present invention allows charging to be concentrated in the necessary locations compared to the conventional charging method, which is extremely beneficial for blast furnace operation. . In addition, since the distribution chute always rotates in a constant direction at a constant speed, there is no overload applied to the rotation motor.
Damage to the motor and waste of power can be eliminated.

[Brief explanation of drawings]

Figure 1 is a schematic diagram of a bellless charging device;
Fig. 2 is a diagram explaining a charging method using a conventional bell-less charging device; Fig. 3 is a diagram showing a comparison of changes in the rotational speed of the distribution chute over time;
FIG. 4 is a schematic configuration diagram of an apparatus for carrying out the charging method according to the present invention, FIG. 5 is a diagram explaining the charging method according to the present invention, and FIGS. 6 A to C are cold models of the present invention. Fig. 6 is a diagram showing the charging equipment when carrying out the charging method, in which A is an enlarged plan view of the charging section, B is a view taken along BB of Fig. 6A, and C is a view of the charging section; Line C- in the diagram
It is a sectional view along C. 5: Hopper, 8: Control gate valve, 9:
Distribution chute, 10: Inside the furnace.

Claims (1)

[Claims] 1 A bellless blast furnace in which a hopper for storing raw materials is provided at the top of the blast furnace, a rotatable chute is provided at the bottom of the hopper, and the raw materials in the hopper are charged into the blast furnace from the chute by controlling the opening and closing of a control gate valve. In the charging method, the chute is rotated in a constant direction at a desired speed, and the control gate valve is opened or closed only in an arbitrarily set angular range in the circumferential direction. How to enter.