JPH0441274B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Industrial Application Field The present invention relates to a method for charging raw materials into a refining furnace.

(b) Prior art The conventional method of charging raw materials into a refining furnace is, for example, in the case of a bellless furnace top charging device, as shown in Fig. 2.
A raw material storage hopper 2, a lower raw material collection hopper 3, and a distribution chute 4 are provided at the top of the refining furnace 1, and raw materials are charged into the furnace. A material repulsion plate 5 such as a stone box is provided to prevent wear of the inner liner of the hopper 2 during material charging.

Changes over time in the particle size of the raw material discharged from the raw material hopper 2, which is an auxiliary equipment of the smelting furnace 1, have a significant effect on the distribution of the raw material charge in the smelting furnace 1. In particular, in a countercurrent reduction refining furnace of reducing gas and granular raw material, controlling the change in raw material particle size over time is one of the dominant factors that determines the utilization efficiency of reducing gas and the pressure drop of the raw material packed bed.

As a method to minimize the change in particle size of the raw material discharged from the raw material hopper 2 over time, a raw material rectifying plate (repulsion plate) is used.
A method has been proposed in which the flow rate is fixedly installed near the hopper 2 exit and the raw material discharge status is changed from funnel flow to mass flow (piston flow) (Kawasaki Steel Technical Report 1982, Vol. 14, No. 4, pp. 405-415). ). However, in this method, there is a risk that the raw material may hang on the shelf due to the raw material baffle plate being installed near the outlet.

For reference, the funnel flow at the time of raw material discharge in the conventional raw material hopper 2 is shown in Figure 3 A, B,
Shown over time in C, D, and E. As shown in the figure, coarse-grained raw materials tend to be delayed in discharge due to sidewall resistance.

This phenomenon is shown in FIG. In the figure, the model hopper is shown by a broken line, and the actual hopper is shown by a solid line. It can be seen from the figure that as the raw material discharge time increases, the coarse particles of the raw material increase.

Further, as shown in FIG. 5A, when the repulsion plate 5 in the hopper 2 is not provided, the pattern of the particle size of the raw material discharged from the hopper with time increases monotonically. As a result, the gas flow in the refining furnace 1 becomes a central flow type (fifth
Figure B).

On the other hand, as shown in FIG. 6A, when the repulsion plate 5 is provided in the hopper 2, the pattern of change in particle size of the discharged raw material over time tends to be smoothed. As a result, the gas flow in the refining furnace 1 becomes a wall flow type (FIG. 6B).

(c) Problems to be Solved by the Invention The problems to be solved by the present invention are to reduce changes in particle size of discharged raw material over time by utilizing the effect of alleviating particle size deviation exerted by a repulsion plate provided in the hopper. The object of the present invention is to obtain a method of charging raw materials to a smelting furnace that can be controlled.

(d) Means for Solving Problems The method of charging raw materials into a smelting furnace of the present invention is a method of charging raw materials into a smelting furnace via a raw material storage hopper. By adjusting the height of the repulsion plate, the particle size distribution of the raw material in the radial direction inside the hopper is controlled when the raw material is deposited in the hopper, and thereby the raw material particle size distribution when the raw material is discharged from the hopper is controlled. The above problems are solved by controlling the particle size change pattern over time.

(e) Examples Next, examples of the method of the present invention will be described with reference to the drawings. As shown in Figure 1, hopper 2
The repulsion plate 5 provided therein is movable and adjustable in vertical and horizontal directions by an external drive device (not shown).

The repulsion plate 5 is made of a stone box or the like, and its shape may be a rectangular parallelepiped, a cylinder, a hemisphere, or the like.

As shown in Fig. 1, when the installation height of the repulsion plate 5 in the hopper 2 is L, and the height of the charged material in the hopper 2 is Lo, the dimensionless repulsion plate height is L/Lo. do. On the other hand, when the standard deviation of the average particle size of the raw material particles discharged from the hopper 2 at each point in time is σdp, and the average particle size of all raw materials in the hopper 2 is dp , the dimensionless raw material particle size deviation is σdp／ dp
shall be.

FIG. 7A shows the relationship between σdp/ dp and L/Lo when the method of the present invention is applied to an actual hopper. FIG. 7B shows a similar relationship according to the conventional method for comparison.

Figure 8 shows the change in raw material particle size over time when sintered ore is charged into an actual blast furnace from a hopper. Curves A and B in the figure are at levels A and B of the repulsion plate 5 in FIG.

FIG. 10 shows the raw material particle size distribution at each level of the raw material in the hopper 2 shown in FIG. 11.

As is clear from a comparison of FIGS. 7A and 7B, the method of the present invention is quite different in the relationship between the deviation in the ejected particle diameter over time and the height of the repulsion plate. While the conventional method controls the material when it is discharged from the hopper, the method of the present invention controls the material when it is charged into the hopper.

As can be seen from FIG. 10, the deviation of the raw material particle size distribution in the radial direction is smaller than the level where the raw material charging into the hopper has progressed to below the repulsion plate installation level. Therefore, by changing the height of the repulsion plate, it is possible to arbitrarily control the change in particle size of the raw material discharged from the hopper over time, as shown in Fig. The controllability of the raw material particle size distribution can be dramatically improved.

The method of the present invention can be applied not only to the hopper in the immediate vicinity of the smelting furnace, but also as a method for controlling the particle size change pattern of the discharged raw material in the relay hopper, and is an effective control means for controlling the gas flow distribution in the smelting furnace.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of an embodiment of the method of the present invention. Second
The figure is an explanatory diagram of an example of a conventional method of charging raw materials into a refining furnace. FIG. 3 is an explanatory diagram of the funnel flow of raw materials in the hopper. Figure 4 is a graph showing the change in particle size of the raw material discharged from the hopper according to the conventional method. Figure 5 shows the temporal change pattern of the particle size of the raw material discharged from the hopper and the gas flow pattern of the refining furnace according to the conventional method. FIG. 6 is a drawing similar to FIG. 5, but according to the method of the present invention. FIG. 7 is a graph showing the relationship between the particle size deviation of the raw material discharged from the hopper and the height of the repulsion plate. FIG. 8 is a graph showing changes in raw material particle size over time. FIG. 9 is an explanatory diagram of the repulsion plate position set to obtain the results shown in FIG. 8. FIG. 10 is a distribution diagram of the average particle size of the raw material at each position within the raw material in the hopper. FIG. 11 is an explanatory diagram showing each position of the repulsion plate within the raw material in the hopper related to FIG. 10. 1... Refining furnace, 2... Hotsupa, 5... Repulsion board.

Claims (1)

[Claims] 1. In a method of charging raw materials into a refining furnace via a raw material storage hopper, by adjusting the height of a raw material repulsion plate installed in the hopper, the height of the raw material being deposited in the hopper can be adjusted. A method for charging raw material into a smelting furnace, characterized in that the raw material particle size distribution in the radial direction within the hopper is controlled, thereby controlling the pattern of change in raw material particle size over time when the raw material is discharged from the hopper.