JPS63317606A - Method for charging raw material in blast furnace - Google Patents

Abstract

PURPOSE:To uniformize gas permeability in a furnace and to stabilize furnace condition in the blast furnace by alternately forming coke layers and mixed layers of coke and ore at top furnace part at the time of charging raw material in the blast furnace providing bell-less raw material charging apparatus. CONSTITUTION:The coke layers (a) and the ore layers (b) are alternately laminated in top furnace raw material hopper 2 in the blast furnace 4 with a belt conveyor 1 from a coke hopper 7 and an ore hopper 8, and also in the other top furnace hopper 2a, coke (a) is charged. These raw materials are alternately laminated into the coke layers 5 from a coke hopper 2a and the mixed layers 6 of coke and ore from the laminated layer hopper 2 by a gyrating chute 3 in bell-less raw material charging apparatus. As the mixed layer 6 of coke and ore is stabilized in the radial direction in the blast furnace and uniform distribution of the coke can be secured, the gas permeability in the whole blast furnace is uniformized, and the stabilization of the furnace condition and the productivity in the blast furnace are improved.

Description

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

[Conventional technology]

Conventionally, the method of charging raw materials into a blast furnace is to charge ore and coke together, and the ore layer and coke layer form a layer inside the furnace, and the thickness and shape of the layers must be maintained at an appropriate level. In current blast furnace operations, this is an important technology for stable operation and improving thermal efficiency. The ore layer charged into the furnace is reduced and fused as it descends inside the furnace. This part is usually called a cohesive zone, and because it is fused like a bedrock, the porosity is extremely small. For this reason, the feather f':I
The high-temperature gas generated in 1ii7 ascends through the coke part of the core, which has a large porosity and low ventilation resistance, and is distributed to the furnace wall in the radial direction of the furnace through the slit-shaped coke layer between the cohesive zones of the ore. Therefore, it is necessary to maintain a coke slit formation that evenly distributes gas from the core coke portion toward the furnace wall in the circumferential direction. However, as a result, there is always a part in the center where the gas utilization rate is low, and the blast furnace as a whole has the disadvantage of poor thermal efficiency.

On the other hand, in JP-A-55-79 s lo:'f, coke and ore are deposited in a mixed state, and gas is also distributed through the voids formed at the boundary between the mixed coke and the fused ore. This improves ventilation throughout the blast furnace,
Furthermore, it is stated that the gas utilization rate and thermal efficiency are improved.

However, it is very difficult to uniformly distribute coke and ores in a predetermined ratio at the top of the blast furnace.

JP-A No. 61-243106 discloses a method in which coke is stored together with ores in a hopper for cutting ores, and these ores and coke are cut into a charging conveyor L.
In this method, materials are charged into the furnace so that a predetermined mixture is obtained during the charging process.

Furthermore, in JP-A No. 61-243108, coke and ores are cut so as to be stacked on a charging belt conveyor by controlling the cutting timing of a coke hopper and an ore hopper, and the stacked two are charged into a blast furnace. This method is used to form a mixed layer of ore and coke.

The above-mentioned JP-A-61-243106 and JP-A-61-
When loaded in a stacked or mixed state on a belt conveyor as in No. 243108, when loaded into the temporary storage device at the top of the furnace or above the bell, coke may segregate with respect to ores due to differences in particle size and specific gravity. However, most coke is deposited on the side walls of the temporary storage device, and ore is deposited in the center.

On the other hand, the discharge from the temporary storage device and the bell is preferentially discharged from the center, which has the disadvantage that the ore and coke are mixed unevenly in the radial direction at the top of the blast furnace. Therefore, the effect of improving air permeability due to the mixing state in the furnace is lacking.

The permeability of the cohesive zone, which is a characteristic of the mixed charging method, is accompanied by an increase in heat dissipation from the furnace wall. On the other hand, the uneven mixing distribution of ore and coke in the radial direction described above is unfavorable for blast furnace operation. Moreover, it has a negative effect on the controllability of the furnace wall heat load.

[Problem that the invention seeks to solve]

By forming a mixed layer of ore with an appropriate amount of coke mixed into the ore layer charged in the blast furnace, the permeability of the cohesive zone formed in the blast furnace is improved compared to conventional stratified charging. In contrast, it has been revised to a degree that is favorable for operation. However, when mixing coke into ores to bring about the effect of improving air permeability, it is necessary to adjust the amount of coke mixed in as necessary and to ensure proper dispersibility in the ore layer. In order to satisfy these conditions, firstly, it is necessary to adopt a charging method that is suitable for blast furnace operation. Secondly, from the viewpoint of protecting the furnace wall and improving thermal efficiency, it is necessary to suppress excessive heat load on the furnace wall.

The present invention was devised in view of the above circumstances, and an object of the present invention is to provide a new raw material charging method that can improve the ventilation inside the furnace.

[Means for solving problems]

The present invention is intended to solve the above-mentioned problems, and is to charge raw materials into the blast furnace from the top of the furnace through a storage device that temporarily stores the charged materials, which is installed at the top of the bellless blast furnace. In order to do so, we adopted the following technical measures. In other words, after depositing one or more raw material layers in the order of a coke layer as a lower layer and an ore layer as an upper layer in a temporary storage device, the material is top-charged from the temporary storage device into a blast furnace. I took it.

[Effect]

The present invention will be described in detail. Figure 2 shows the experimental results using a model device. Figure 2 (a) shows the loading of coke a and ore in the furnace top hopper and belt conveyor, and Figure 2 (b) shows the situation in the furnace. Figure 2 (c) shows the change in the mixing degree of ore and coke during discharge from the top hopper, and shows the distribution of the mixing degree of ore and coke at the top of the furnace. The method of JP-A No. 61-243108 mentioned above is based on
, is similar to that shown in ■, but when coke a and ore are stacked on a belt conveyor and loaded into the furnace top hopper, coke a tends to move toward the wall because the particle size of coke a is larger than that of ore. The ore sludge is deposited in the center, and the degree of mixing between coke a and ore sludge is poor at the time of discharge.

On the other hand, if the coke a and the ore are conveyed separately by a belt conveyor and stacked in layers in the furnace top hopper, the degree of mixing of the coke a and the ore is better at the time of discharge. Figure 2 (a
) As shown in (2) of Figure 2 ('a), if the ore is stacked in the lower layer, the degree of mixing of coke a and ore is poor at the time of discharge, but the As shown, the degree of mixing at the time of charging is better when coke a is layered under the ore. Moreover, the more evenly the mixture is discharged as the layers are stacked in multiple layers, with a layer of ore on top and three layers of coke on the bottom.

As explained above, if ore sulfur is loaded into the lowest layer of the furnace top hopper, it will be discharged first, and if coke a and ore sulfate are layered and coke a is charged in the bottom layer of ore sludge, the furnace It has been found that a predetermined amount of coke can be mixed into the ore layer in the radial direction of the top and can be uniformly dispersed.

FIG. 3 shows a raw material charging device that can suitably carry out the method of the present invention. As shown in FIG. 3, the device is equipped with a coke hopper 7 and an ore hopper 8 for cutting raw materials on a belt conveyor 1, and a predetermined amount of coke a and The ores are cut out in order and deposited in the furnace top hopper 2 in this order. Coke a is charged into the blast furnace from one furnace top hopper 2a and deposited on the furnace top, and then coke a and ore are discharged from the furnace top hopper 2. At the time of discharge, the two are well mixed and Coke a can be uniformly mixed and deposited in the ore/coke mixed layer 6 in the radial direction of the blast furnace at the top.

〔Example〕

As shown in FIG. 3, when charging and forming a raw material layer in the blast furnace 4, a predetermined amount is cut out separately from the coke hopper 7 and the ore hopper 8, conveyed by a belt conveyor l, and placed in the furnace top hopper z. Layer coke a and ore in this order,
By charging the raw materials stacked in the furnace top hopper 2 into the blast furnace 4, an ore/coke mixed layer 6 was formed in the furnace. On the Kimino side, the ore/coke mixed layer 6 is charged and formed alternately with the coke layer 5.

FIG. 1 shows an example of operation in which the method of the invention was carried out.

Compared to the conventional example, the method of the present invention uses the same amount of air! It can be seen that the blowing pressure can be lowered, the air permeability is improved, and the gas utilization rate is improved.

〔Effect of the invention〕

According to the present invention, it is possible to mix a predetermined amount of coke when charging an ore layer and to form an ore/coke mixed layer stably in the radial direction of the blast furnace while ensuring uniform dispersion of coke. As a result, the permeability and gas utilization rate of the blast furnace are greatly improved, resulting in excellent effects on high productivity and stable operation.

[Brief Description of the Drawings] Fig. 1 is a graph showing the results of implementing the present invention, Fig. 2 is an explanatory diagram of the operation of the present invention using a model device, and Fig. 3 is an explanatory diagram of equipment for preferably implementing the present invention. be. ■... Belt conveyor 2.2a... Furnace top hopper 3
...Swivel chute 4...Blast furnace 5...Coke layer 6...Ore/coke mixed layer

Claims (1)

[Scope of Claims] 1. When charging raw materials from the top of the furnace into the blast furnace via a storage device provided at the top of the bellless blast furnace for temporarily storing the charged raw materials, the temporary storage The method is characterized in that, after one or more raw material layers are deposited in the apparatus, the lower layer being a coke layer and the upper layer being an ore layer, the raw materials are charged into the blast furnace from the temporary storage device. How to charge raw materials into a blast furnace.