SU1710579A1 - Method of charging burden materials into blast furnaces - Google Patents

Abstract

The invention relates to blast furnace production and can be applied when charging materials to blast furnaces. The purpose of the invention is to reduce the specific consumption of coke and increase productivity by increasing the use of the reducing ability of the gas. Before loading the batch materials into the furnace, fractions of δ - (25 - 35) and more (25 - 35) mm are preliminarily isolated from the agglomerate. Each of these fractions is loaded into skips together with coke, and alternate between themselves either skips with large and small agglomerate, or feeds, which allow to increase the relative amount. in the ore materials in the central zone of the furnace, without reducing the gas permeability of this zone, which increases the degree of utilization of the reducing ability of the gas. 2 ill., 1 tabl, ^ And

Description

The invention relates to ferrous metallurgy, in particular to methods of loading and distribution of materials on a blast furnace to a cocoon / vomit.

The aim of the invention is to reduce the specific consumption of coke and increase productivity by increasing the use of the gas reduction ability. V

FIG. Figure 1 shows a graph of the change in gas dynamic resistance of coke blends with fine fractions of agglomerate, 5 - (10-50) mm; in fig. 2 is a graph showing the change in gasdynamic resistance cm1; this coke with large fractions of agglomerate. K100-50) mm.

The method is carried out as follows.

From the agglomerate, fractions of 5 - (25 -35) and (25-35) mm size are pre-separated, each of which is loaded into skips together with coke and alternate inside the feed skips containing small agglomerate and skips containing large agglomerate, or alternate among themselves feed with fine agglomerate and feed with large agglomerate.

The separation of agglomerate 1 into fractions of 5 (25-35) mm and (25-35) mm is justified by the results of experiments conducted on a laboratory setup.

The studies were carried out on an installation made in the form of a cylinder with an inner diameter of 300 mm and a height of 750 mm, having in its lower part a fitting for blowing in. The cylinder cavity at the point of supply is separated by a metal grid from the working space filled with a mixture of materials. The pressure in the grid of the cylinder is measured using a water pressure gauge, which gives an idea of the amount of pressure loss in the layer of materials

The studies were carried out at a constant air flow, corresponding to a reduced speed of 0.9 m / s (calculated on the total cross-section of the cylinder), which ensures compliance with the conditions of self-similarity.

An agglomerate with a particle size of 5-60 mm and coke of 40-80 mm is used for the study. In different series of experiments, the agglomerate is dispersed into small and large fractions: 5-10 and 10 mm, 5-10 and 20 mm, 5-25 and 25 mm, 5-30 and 30 mm, 5-35 and 35 mm, 5-40 and , 40 mm, 5-50 and 50 mm. Each of the listed fractions is mixed with coke in a different quantitative ratio by volume and the gas-dynamic resistance of the resulting mixtures is determined. The percentage of agglomerate in the mixture varies from 20 to 80% every 20%,

Experiments are carried out in the following order.

First, a mixture of coke with a fine fraction of agglomerate of 5-10 mm is prepared, the content of which in the mixture is 20% by volume. The mixture is charged to the unit, purged with air, and the pressure loss in the bed is determined. Similar measurements are made for mixtures in which the content of the agglomerate fraction 5-10 mm is 40, 60 and 80%. Then, coarse friction of the agglomerate, 10 mm is mixed in the same proportion with coke, and the pressure loss in the bed is determined for these mixtures.

Similarly, the gas-dynamic resistance of small and large fractions of other sizes is measured.

The results of these studies are shown in FIG. 1 and 2.

The curves in FIG. 1 are built for coke blends with fine agglomerate.

 The horizontal axis represents the percentage of agglomerate in the mixture by volume, and the vertical axis shows the loss of pressure to blow (L P) in terms of Ix of the layer height. The numbers at the curves correspond to the fractions of different size:

1-5-10 mm; 2-5 - 20 mm; 3-5 - 25 mm;

4-5 - 30 mm; 5-5 - 35 mm; 6-5 - 40 mm; 7-5-50 mm.

The curves show that when mixing fine fractions of agglomerate with coke, an increase in the proportion of agglomerate in the mixture is accompanied by an increase in its gas-dynamic resistance. This pattern is enhanced with decreasing agglomerate size.

Thus, the change in the quantitative ratio between coke and small

the fraction of the agglomerate in the mixture in any zone of the furnace makes it possible to significantly change the gas permeability of the charge in this zone, which ensures affective control of the gas flow. Moreover, the efficiency of such control increases with decreasing size of the fines fraction.

FIG. 2 shows the results of the study of the gas permeability of mixtures composed of coke and coarse fractions.

agglomerate.

On the graph, the horizontal axis shows the percentage of sinter in the mixture by volume, and the vertical axis shows the pressure loss to blow (AR) in terms of 1 m.

height of

The numbers at the curves correspond to the fractions:.

1–10 mm; 3-25 mm; 4-30 mm; 5- 35 mm; 6-40 mm;

 7-50 mm.

The presented curves show that an increase in the share of agglomerate in its mixture with coke has a different effect on the gas-dynamic resistance of the mixture, depending on

from agglomerate size. So, when mixed with a coke of agglomerate fraction of 10 mm, an increase in its content in the mixture is accompanied by a significant increase in pressure loss in the bed. This dependence weakens with an increase in the size of the agglomerate. When mixed with the coke fraction of 20 mm, an increase in its content in the mixture is accompanied by a less significant increase in pressure loss than when mixed

fraction 10 mm. When mixed with coke with fractions larger than 25 mm, the gas-dynamic resistance of the layer varies slightly with an increase in the proportion of agglomerate in the mixture. The nature of the boot method requires two conditions:

1, The change in the quantitative ratio of coke and fine fraction of the agglomerate in their mixture should be accompanied by significant changes in gas permeability; the bridges of this mixture,

2. The change in the quantitative ratio of coke and coarse fraction of the agglomerate should be accompanied by a minimum change in the gas permeability of the mixture,

Observance of the first of these conditions provides the necessary efficiency of control of the radial gas distribution in the furnace when applying the proposed loading method.

Compliance with the second condition allows the central zone of the furnace to be loaded with an agglomerate without reducing the gas permeability of this zone.

The analysis shown in FIG. Curves 1 and 2 suggest that the limits of 25-35 mm correspond to this optimal range. The values of the boundary size of the fractions in this range ensure the separation of the agglomerate into such large and small fractions, the mixing of which with coke ensures that the conditions discussed above are fulfilled. In particular, when a large fraction is mixed with coke, changes in its content in the mixture are not accompanied by significant changes in the gas permeability of the mixture (Fig. 2). And when mixing the remaining fine fraction with coke, a change in the relative amount of this fraction in the mixture is accompanied by significant changes in the gas permeability of the mixture (Fig. 1). According to the schedule, these changes in gas permeability are more significant than, for example, when mixing coke with a fraction of 5-50 mm and, especially, with an agglomerate not subjected to sieving into small and coarse fractions.

Example. The agglomerate directed to the blast furnace is subjected to sieving with separation of two fractions, for example 5-30 mm and 30 mm, which are loaded separately into the receiving bunkers of the blast furnaces.

When the furnace is loaded from these two fractions, it is fed to the skip together with coke, which ensures the mixing of the ore and fuel components.

The loading of both components into the skip can be carried out simultaneously and alternately. With alternate loading, mixing of iron ore with coke occurs in the process of overloading these materials from skip to a small cone, from a small cone to a large cone, and then into the furnace. When simultaneously fed into the skip of agglomerate and coke, their mixing to a large extent occurs already at the stage of filling the skip.

One of the variants of the method implementation is that skips containing small agglomerate with coke and skips containing large agglomerate with coke alternate within the feed limits. Changing this sequence allows gas flow control.

Such loading is applied both in the mode of simultaneous pouring into the skip of agglomerate and coke, and in the mode of their alternate dumping.

In the simultaneous siphoning mode, the gas flow control is performed

changing the order of skips with small and large agglomerate, for example:

Ka KA KA; Ka Ka Ka Ka; KA KA KA. In the alternate dumping mode, the gas flow is controlled by changing the order of dumping into the skim of sinter and coke and changing the order of skips containing small and large agglomerate, for example:

K K K K; a a K K: K A K K.

a a A AK K A A A K A A

Preferably, loading systems are used that facilitate the placement of a large agglomerate in a relatively large amount in the center of the furnace, and small ones in the peripheral and intermediate zones.

Another embodiment of the loading method is that small and large agglomerate is fed to skips along with

coke, but are not present in the same feed, but are loaded into the furnace in different feeds. At the same time, the feeds containing fine agglomerate alternate with feeds containing large agglomerate.

In this case, gas flow control is carried out by changing the order of supply to the sinter of agglomerate and coke using cyclical loading systems of the type:

. KKKK, AAAA about -: Not

KKKK

aa aa

m - ;; h P., ...,, etc.,

Kaaa KKAA

where b, s, m, n - the number of innings of different types.

When loading feeds containing large agglomerate, loading systems are used to facilitate the loading of the central zone of the furnace with an agglomerate. When loading feeds containing fine agglomerate, systems are used that ensure the placement of fine agglomerate in the peripheral and intermediate zones.

For three days at the blast furnace with a useful volume of 2000 m of the West-Siberian Metallurgical Combine them. 50 years of Great Oct. Oct. were carried out experimental melting using the proposed method of loading.

The furnace is equipped with a conveyor feed of the charge to the skips.

Sintering mill agglomerate, pellets of Lebedinsky GOK, Tashtagolsk iron ore enters the mixture. The share of pellets in the ore part of the charge is about 12%, the share of ore is about 8%.

The feed consists of 38-40 tons of ore materials and 9.7-10.5 tons of coke.

Pry nenim experienced melts fractions of agglomerate with a particle size of 5-30 mm and 30 mm are loaded separately into blast furnace receiving bins, and when the furnace is loaded, each of these fractions is served in a skip together with coke and alternate inside the feed skips containing a mixture of fine agglomerate with coke, and skips of a mixture of coarse agglomerate with coke or alternate between the supply of small agglomerate with coke and the supply of coarse agglomerate with coke. For the implementation of joint loading and ore raw materials and coke in the skip portions of these materials, recruited into the weight funnels, halve compared with the usual loading.

Pellets and ore are served together with small agglomerate.

During the research period, the mode of simultaneous pouring into the skip of the ore and fuel components and the mode of alternate joint feeding of these components to the skip were tested.

With simultaneous dumping, the gas flow is controlled by alternating skips containing a mixture of fine agglomerate with coke and skips of a mixture of coarse agglomerate with coke inside the feed. The following loading systems are used:

Ka KA KA; KA KA KA; Ka Ka Ka Ka.

When alternately feeding in skip agglomerate and coke alternate between the supply of fine agglomerate with coke and the supply of large agglomerate with coke, using cyclic loading systems:

2 feeds

and 1 serve

KKKK

aa aaaa kccc and 2 filing

2 filing

ahhh kkaa

The use of these loading systems during the research period allows for a favorable gas distribution in the furnace.

Comparative results of the tests of the method are presented in the table.

The alternation of feeds with fine agglomerate and the supply of large agglomerate, as well as the alternation of feedstocks of skips containing fine agglomerate with coke and bits containing large agglomerate with coke, allows to increase the relative amount of the ore component in the central zone of the furnace without reducing the permeability of the mixture to this zone and not weakened here the intensity of the gas stream. Thus, it is possible to maintain a smooth flow of the charge and stable operation of the furnace, while ensuring an increase in the degree of utilization of the reducing ability of gas in the central zone and the furnace as a whole.

The increase in the share of ore raw materials in the charge, loaded into the central zone, provides an increase in the degree of utilization of the reducing ability of gas in this zone and in the furnace as a whole and reducing the specific coke consumption by 2.1%.

Claims (1)

The invention of the method of loading charge materials into a blast furnace, including the loading of coke, iron ore materials, pellets and agglomerate with a fraction of 5 mm in skips, feed into the furnace and distribution in the furnace, characterized in that. that, in order to reduce the specific consumption of coke and increase productivity by increasing the use of reducing the ability of the gas, the agglomerate is pre-divided into fractions of grain size of 22535 mm and (25-35) mm, each ii3 of which is loaded into skips together with coke, alternate inside skip skids containing fine agglomerate, and skipm, containing large agglomerate, or alternate between feeding with fine agglomerate and feeding with large agglomerate. Table continuation 60% agglomerate d mixture F1 / g.1 80 60% aejfOMepafna FIG. g 80 8 mixture