JP3071564B2 - Charging method and charging device in vertical furnace - 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 and an apparatus for charging a charge in a vertical furnace such as a blast furnace.

[0002]

2. Description of the Related Art Conventionally, there are a number of techniques relating to a method of charging a blast furnace with a charge, which can be broadly classified into the following two. That is, a bell system and a bellless system are used. In the bell method, the charge slides down on a conical bell that also functions as a gas seal valve called a large bell, and then hits a rebound plate called a movable armor, and the position of the charge is adjusted by adjusting its position. This is a charging method for controlling the charging. In the bell-less method, the charge falling from the hopper is received by a gutter-shaped chute inclined at a certain angle, and the inclination of the chute is adjusted during charging to control the drop position of the charge. Is the way.

[0003]

However, the conventional charging method has the following problems. In the conventional bell-type charging method, the drop position of the charged material is mainly limited to the vicinity of the furnace wall, and the selection range of the control is limited. In addition, in the bellless type charging method, although the controllability of the drop position is wide, the charging amount per unit time is small, so that the particle size segregation is large, and a complicated charging method is required to control this. .

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and when charging a charged material in a vertical furnace, after the charged material starts dropping in the furnace, gas is discharged. to control the falling trajectory of the charge by blowing the charge to fall
This is a charging method in a vertical furnace, wherein the shape of the charged material is adjusted . Further, it is also characterized by controlling the radial particle size distribution of the furnace of the charge by blowing the gas to the charge in three or more stages during the fall.

[0005] A vertical dropping chute and a gas injection cylinder located at the center of the charging drop chute and protruding from the tip of the charging drop chute are provided. In the charging apparatus for a vertical furnace, the injection nozzles that jet to the nozzle are provided at three or more stages at different height positions, and the injection nozzles are provided with pipes that inject gas independently at each stage. is there.

[0006]

The present invention will be described in detail below together with the operation. In a conventional charging device, the main factor that determines the drop position of the charge is
In the bell system, it is the diameter of the large bell and the collision position of the load with the movable armor, and in the bellless system, it is the length and the tilt angle of the turning chute. However, in the present invention, the location, amount, and speed of the gas or gaseous fluid are the main factors that control the falling position and the particle size distribution of the charge. The principle of the control will be described below. When the charge is blown with gas, it is dragged by the gas flow as shown in FIG. In the case of a single particle, the motion of the particle can be predicted by Newton's law as follows. The following drag force acts on the particles moving in the fluid.

[0007]

(Equation 1)

Here, R; drag C; drag coefficient (drag coefficient) 10 ^-4 <Re <0.3 C = 24 / Re (Stok
es range) (However, Re is Reynolds number) 2 <Re <500 C = 24 / Re ^0.5 (Alle
n range) 500 <Re <10 ⁵ C = 0.44 (Newto
n) A: Projected area of particle perpendicular to the direction of particle movement ρ; Fluid density u; Relative velocity between particle and fluid

The following differential equation holds because the drag R causes acceleration of the particles.

[0010]

(Equation 2)

[0011]

(Equation 3)

The projected area A of the falling particles in the drag R, the mass m
Is represented by the following equation, and the above differential equation is modified as follows.

[0013]

(Equation 4)

[0014]

(Equation 5)

[0015]

(Equation 6)

[0016]

(Equation 7)

The above results are summarized as follows.
However, D _p, the diameter of the [rho _p each particle, density and u _p, u _g are each particle, gas velocity.

[0018]

(Equation 8)

[0019]

(Equation 9)

[0020]

(Equation 10)

The differential equation number 8 can be solved analytically if C is not a function of the Reynolds number, but the differential equation number 9 in the y direction cannot be solved even if C is a constant. But Ru
It can be analyzed by numerical calculation by the nge-Kutta-Gill method or the like. From this formula, the smaller the density and particle diameter of the dropped charge and the higher the blowing gas flow rate, the farther it is blown away, and if you control the flow rate and type of the blowing gas according to the particle diameter and density, it will drop The position can be controlled.

FIG. 1 shows an example of a charging device using a gas fluid. A gas injection cylinder 2 is provided concentrically at the center of the vertical load drop chute 1 so as to protrude from the tip of the load drop chute and discharge gas from this portion. Numeral 3 indicates a falling trajectory of the charge, and numeral 4 indicates a deposited state of the charge.

FIG. 2 is a cross-sectional view of a portion of the gas injection cylinder 2 of the charging apparatus of FIG. 1, and the gas injection cylinder 2 has injection nozzles 5a, 5b, and 5c for jetting gas in a radial direction. It is provided in three stages with different lengths. It is preferable to radially inject the gas over the entire circumference of the injection nozzle, but in this example, the gas is injected in four directions at intervals of 90 degrees, and the same effect is achieved by the rotation 6 of the gas injection cylinder. . The gas is supplied to the injection nozzles 5a, 5b, and 5c of the respective stages by independent pipes 7a, 7b, and 7c, and the flow rate can be set separately.

The particles 3 falling from the vertical load drop chute 1 are blown outward from the chute by the injection nozzle 5a. The particles blown outward are further given a velocity vector in a predetermined furnace wall direction by the injection nozzle 5b. At this time, since the vector given outward differs depending on the size of the particles, and the falling position of the charge differs, the particle size segregation occurs as shown by 3a and 3b. In order to control this, an injection nozzle shown in 5c is further provided, and only the falling position of the coarse particles 3b falling inside the furnace is changed,
Particle size segregation is controlled by blowing gas at an appropriate flow rate and velocity so as not to affect fine particles 5a falling outside. In addition, the injection nozzles are installed in four directions, and furthermore, the rod on which the nozzles are installed rotates, and the injection of gas is performed while rotating, so that the blowing of the gas to the granular material is stabilized. Thus, the injection nozzle is functionally 3
Steps are required, but there may be more.

As described above, the present charging device has no portion for guiding the charged material such as a large bell or a chute, and is therefore a very simple facility. It is possible to control the falling position and the particle size segregation. The gas to be used may be air, inert gas, or any other gas that does not interfere with the operation of the furnace.

[0026]

Examples of the present invention will be described below. For Blast furnace A, the charging method was changed to bell and bellless, but this method has been further changed to this method. Table 1 shows the results. The bellless charging device has a large particle size analysis, and it is necessary to sacrifice consideration for the deposition shape in order to optimize the analysis. However, since switching to this apparatus, the control of the deposition shape and the particle size distribution can be performed simultaneously, and the degree of freedom of operation has increased.

[0027]

[Table 1]

[0028]

According to the present invention, compared with the conventional bell-type or bell-less type charging method, the equipment cost and equipment maintenance cost can be reduced.
This is effective in improving the controllability of the charge distribution.

[Brief description of the drawings]

FIG. 1 is an overall view of a charging device.

FIG. 2 is an enlarged sectional view of the charging device of FIG. 1;

FIG. 3 is a diagram showing a relationship between forces acting on a charge.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Charge drop chute 2 Gas injection cylinder 5a, 5b, 5c Injection nozzle 7a, 7b, 7c Piping

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C21B 5/00 311 C21B 7/20 301 F27B 1/20 F27D 3/16

Claims (3)

(57) [Claims] Claims 1. In a vertical furnace, charging a charge in a vertical furnace,
After the charge starts to fall in the furnace, the gas is sprayed on the falling charge to control the fall trajectory of the charge and the charge
A method for charging in a vertical furnace, comprising adjusting the shape of the pile of slag. 2. The vertical method according to claim 1, wherein the gas is blown to the charge in three or more stages during the fall to control the particle size distribution of the charge in the furnace in the radial direction. How to charge in a mold furnace. 3. A vertical dropping chute and a gas injection cylinder located at the center of the charging drop chute and protruding from the tip of the charging drop chute. The injection device for a vertical furnace is characterized in that three or more stages of injection nozzles are provided at different heights, and a pipe for injecting gas is provided for each stage independently.