JPH04183809A - Method for changing raw material in ball-less blast furnace - Google Patents

Abstract

PURPOSE:To charge lumped coke to the core part of a Bell-less type blast furnace and to improve the air ventilation in the core part of the blast furnace so as to stabilize the furnace condition by providing a distributing plate for controlling raw material charging loci in an offcenter type furnace top hopper at the time of charging the raw materials contg. the coke to the above-mentioned blast furnace. CONSTITUTION:The furnace top hopper 1 for charging raw materials of the Bell-less type blast furnace is constituted as the offcenter type hopper, the perpendicular line 4 of which running the center of its discharge port 3 is deviated to the one wall side of the hopper 1. The falling loci 6 of the raw material mixture which consists mainly of iron ore and is charged from a charging port 2 is adjusted by the movement of the distribution plate 5 in the hopper so that the raw material mixture is supplied always near to the inside wall of the furnace top hopper on the perpendicular line 4 side. The raw materials 11 deposited in the furnace top hopper forms slopes 12a to 12d peaking at the side wall position on the perpendicular line side. The raw material mixture glides down on these slopes and, therefore, the coarse grained raw materials 13 segregate in the inside edge of the hopper. The discharge port of the hopper is then opened while the lumped coke is held additionally charged thereon. The deposited layer 29 of the lumped coke is formed in the central part of the raw material mixture layer 28 on the coke layer 27 and the air ventilation of the furnace core part is improved.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for charging raw materials in a bellless blast furnace.

[Conventional technology]

In a bellless blast furnace, coke and iron ore are alternately charged into the blast furnace using a rotating chute.

In this case, a so-called mixed charging technique is known in which coke is mixed into the ore layer to promote heating, reduction, and melting of the iron ore. FIG. 4 shows a flow sheet of the raw material charging system of the blast furnace 2o, in which the ore and coke are mixed by stacking them on a belt conveyor 22 when discharging from the ore storage tank 21, or by stacking them on a surge hopper. 23 to the belt conveyor 24 or from the furnace top hopper 25 to the rotating chute 26, both are discharged simultaneously.

In general, in a blast furnace, if the ventilation resistance in the center of the blast furnace is reduced and the amount of ventilation in the center of the blast furnace is ensured, favorable furnace conditions can be achieved stably, and improvements in productivity, quality stability, and reduction in consumption can be expected. can.

In order to ensure such ventilation inside the furnace,
In Publication No. 6003, crude coke is charged in a single batch into the center of a blast furnace. However, this method increases the step of charging only crude coke into the center of the furnace, which reduces the amount charged into the blast furnace and impedes productivity.

Further, in Japanese Patent Application Laid-Open No. 62-127414, raw materials are charged using a rotating chute in order from the center of the furnace toward the wall of the furnace. It is practically difficult to increase the central flow by this method.

[Problems to be Solved by the Invention] Therefore, in the present invention, as shown in FIG.
A method has been developed in which coarse-grained raw materials are charged into the reactor core 29 of the reactor, and this method is realized by particle size segregation that occurs in the top hopper.

The present invention aims to provide such means.

[Means to solve the problem]

The present invention is a method for charging raw materials in a bell-less blast furnace, characterized in that the following technical means are combined to charge a mixed raw material in which coke is mixed into ore to be supplied to the bell-less blast furnace into a furnace top hopper. It is.

■ Use an off-center type furnace top hopper.

■ Control the trajectory of raw material input into this furnace top hopper
・Install a distribution plate to

■ Operate the distribution plate to feed the raw material near the inner wall of the hopper on the vertical side of the center of the outlet of the furnace top hopper.

Furthermore, after charging the above-mentioned mixed raw materials into the furnace top hopper,
If additional lump coke is subsequently charged into the top hopper, favorable results can be obtained.

[Function] In the present invention, when charging the mixed raw material into the furnace top hopper,
The hopper is off-center and equipped with a distribution plate that can control the charging trajectory of charging mixed raw materials into the top hopper. Supply mixed raw materials. The furnace top hopper is of an off-center type, and the discharge port is provided on one wall side. The mixed raw materials charged as described above form a unidirectional slope in the furnace top hopper, and segregation occurs on the slope. That is, coarse particles gather at the part farthest from the vertically above the furnace top hopper discharge port, and at this time, maximum segregation occurs within the hopper.

[Example] FIG. 1 shows an embodiment of the present invention.

The furnace top hopper 1 is of an off-center type with its discharge port 3 being eccentric from the center of the furnace top hopper. That is, outlet 3
A vertical line 4 passing through the center of is closer to one wall of the furnace top hopper l. The mixed raw material charged into the furnace top hopper 1 from the charging port 2 has its falling trajectory 6 adjusted by the distribution plate 5, and is always supplied near the inner wall of the furnace top hopper on the vertical line 4 side. The upper surface of the deposited raw material 11 in the furnace top hopper 1 is sloped 12a, 12b whose highest point is the wall surface position on the vertical line 4 side.
, 12c, 12d, etc. are formed. When the mixed raw material slides down on this slope, segregation occurs, and coarse grains gather at the position of coarse grain deposits 13. After one batch is charged, when the gate of the lower discharge port 3 is opened, the mixing ratio of ore and coke in the mixed raw materials discharged changes over time due to segregation on the slope, as shown in Figure 6. As in, initially there was a lot of ore, and eventually there was a lot of coke.

If the mixed raw material deposited in the furnace top hopper is discharged from the furnace top hopper in the state shown in FIG. 1, and the temporal change in the tilt angle of the rotating chute during the discharge is controlled as shown in FIG. 8, As schematically shown in FIG.
In the mixed layer 28 above the furnace, coarse coke deposits 2
9 can be formed. Therefore, the furnace condition is stabilized,
Benefits include improved production and protection of furnace refractories.

Next, the embodiment shown in FIG. 2 will be described.

After charging the mixed raw material 11 into the furnace top hopper in the same manner as in FIG. 1, when lump coke 14 is additionally charged, it segregates as shown in FIG. When this is discharged, lump coke is collected at the end and discharged as shown in FIG. 9(a). 9th
As shown in Figure (b), by changing the tilting angle of the rotating chute from a larger angle to a smaller angle, lump coke can be intensively charged into the center of the blast furnace.

Figure 3 shows the accumulation of mixed raw materials in the conventional furnace top hopper, and the deposit surface in the furnace top hopper is 16a, 16b, 1
6c and 16d, and the lump coke 15 segregates near the surrounding walls. In this case, the temporal changes in the ore and coke in the discharged mixed raw material are as shown in FIG.

Figure 10 is shown for comparison; as shown in Figure 3, the mixed raw material is charged into the furnace top hopper by the conventional method, and lump coke is additionally charged on top (not shown). It shows the change over time of the discharged material when it is discharged from the lower gate. In this case, since the lump coke is discharged during the discharge, it is not possible to segregate the lump coke in the center of the blast furnace.

[Effects of the Invention] According to the present invention, in the mixed charging method of blast furnace raw materials, lump coke can be intensively charged into the center of the blast furnace. Therefore, the flow of gas at the center of the blast furnace is increased, resulting in favorable effects such as stabilizing the furnace condition, increasing production, and protecting the furnace wall.

[Brief explanation of the drawing]

1 and 2 are elevational views including a vertical cross-sectional view of the blast furnace top hopper to explain the present invention in detail, and FIG. 3 is an elevational view including a vertical cross-sectional view of the blast furnace top hopper to explain the conventional method. Fig. 4 is a system diagram of the blast furnace raw material charging route, Fig. 5 is a schematic diagram of the distribution of contents in the blast furnace to be realized by mixed charging according to the present invention, and Fig. 6 is a schematic diagram of the charge distribution in the blast furnace.
FIG. 7 is a graph showing changes over time in the proportion of raw materials in the discharge of the mixed raw material from the blast furnace hopper of the embodiment; FIG.
The figure is a graph showing the change over time in the tilting angle of the rotating chute, FIG. FIG. 10 is a graph showing the change over time in the tilting angle of the rotating chute, and FIG. 1...Furnace top hopper 3...Discharge port 4...Plumb line 5...Distribution plate 6...Fall trajectory 11...Depositing raw materials 12a, 12b, 12c, 12d-...Slope 13...・・・
Coarse grain deposit 14...Lump coke

Claims (1)

[Scope of Claims] 1. When charging a mixture of ore mixed with coke to be supplied to a bellless blast furnace into a top hopper, an off-center type top hopper is used to control the locus of material input into the top hopper. A method for charging raw materials in a bellless blast furnace, characterized in that a distribution plate is provided, and the distribution plate is operated to input raw materials near the inner wall surface of the hopper on the center vertical line side of the furnace top hopper discharge port. 2. The raw material charging method in a bellless blast furnace according to claim 1, further comprising the step of additionally charging lump coke into the furnace top hopper after the mixture has been completely charged into the furnace top hopper.