UA47820A - A method of feeding into the blast-furnace - Google Patents

Abstract

A method of feeding into the blast-furnace includes the separated feed of coke and of iron-ore charge. The iron-ore charge is fed by ring-shaped combs distributed on the furnace throat radius and the coke is fed by concentrated ring-shaped combs to the middle area of the iron-ore comb.

Description

Description of the invention

The invention relates to ferrous metallurgy and can be used when loading blast furnaces. 2 A known method of loading a blast furnace with a tray loading device (AS USSR Mo 1201313, class C2187/20, BV Mo 48, 1985), including rotation and changing the angle of the distribution tray relative to the axis of the furnace at stations with adjustment of the charge volume, which is loaded at each station. The method ensures a relatively uniform distribution of the charge along the radius of the furnace.

There is also a known method of loading a blast furnace with a conical loading device (AS USSR Mo 70 933715, class C2187/18, BV Mo 21, 1982), including loading the charge through a half-opened 0.25 - 0.35 full stroke large cone. The method makes it possible to adjust the radial distribution of the charge by changing the trajectory of its pouring onto the furnace during various movements of the large cone.

The closest method of loading the charge into the blast furnace, a prototype, is the method including retail loading of iron ore charge and coke (V.P. Tarasov, Gas dynamics of the blast furnace process. - M: 12 Metalurgiya, 1990. - 216 p., p. 87). The first semi-feed is loaded when the specified backfill level is reached, and the second - as the skips are added to the large cone. The method makes it possible to sharply increase or decrease the ore load at the walls of the furnace.

All known methods of loading the blast furnace, allowing to regulate the radial distribution of the charge, do not provide a developed gas flow in the area of the greatest concentration of iron ore materials, which limits the development of iron reduction reactions with gases, leads to an increase in the development of endothermic reactions of iron reduction with solid carbon and an increase in coke consumption.

The invention is based on the task of creating a way of loading a blast furnace, in which changing the loading conditions will allow to achieve an increase in the intensity of the gas flow in the zone of the greatest concentration of iron ore materials, which will increase the degree of use of blast furnace gas and reduce coke consumption.

The problem is solved by the fact that in the method of loading the blast furnace, which includes the retail supply of coke and iron ore charge, in accordance with the invention, the iron ore charge is loaded with ring combs distributed along the radius of the blast furnace, and coke is loaded with ring combs concentrated in the middle part of the iron ore comb. Moreover, when using a tray loading device, iron ore charge is loaded at no less than three consecutive stations of the slope of the distribution tray, and coke is loaded at one station about the slope of the distribution tray, corresponding to the middle station when loading the iron ore charge. When using a conical loading device, the iron ore charge and coke are loaded when the specified filling level (measure) is reached, and when loading the iron ore charge, the large cone is lowered more slowly than when loading coke. Cha

Blast furnace charge consists mainly of two components: coke and iron ore materials. More than 3o strong coke, from which a fraction of less than 25 mm is screened before loading into the blast furnace, has a higher gas permeability than iron ore materials containing 15 - 3095 small particles less than B5 mm in size. The change in gas permeability of the charge along the radius of the blast furnace is characterized by the radial distribution of ore loads, the ratio of the mass of iron ore charge to the mass of coke. In radial zones where coke is concentrated and the amount of iron ore charge is small (low ore load), an intense gas flow is formed. At the same time, in the Z 50 region of the ore ridge, where most of the iron ore charge is concentrated and little coke (high ore load), the gas velocity is low.

From" In the upper part of the blast furnace, iron is reduced by blast furnace gas (side reduction). Part of the iron oxides not reduced in the upper part of the furnace is reduced in the lower part by solid carbon (direct reduction) with the absorption of a large amount of heat. The increase in the development of direct reduction is accompanied by an increase in coke consumption. Due to the lack of gas reducing agent in the area of the ore ridge, the processes of iron reduction by gases are inhibited when the blast furnace gas composition approaches equilibrium. This leads to an increase in the direct recovery of the iron ore charge in the area of the ore ridge. In areas with a low ore load, most of the iron is recovered indirectly, but the reducing capacity of the blast furnace gas is not fully used. ka 20 Thus, a contradiction arises in the blast furnace between the low gas permeability of the iron ore charge and the need for a large amount of reducing gas in the ore ridge zone. To solve it, it is necessary to increase the intensity of the gas flow in the area of concentration of iron ore materials. One of the ways to solve the problem is to distribute the charge along the radius of the blast furnace in such a way that the maximum amount of iron ore material corresponds to the reduced ore load. For this, it is necessary to concentrate the maximum amount of coke in the area of ore ridge 52. There are no known methods of loading the blast furnace. allow solving the given problem, because after the formation of the ore ridge, the coke rolls into other radial zones, and the areas of the highest concentration of iron ore materials and coke do not coincide.

In the case of separate loading after reaching the specified filling level, when the shape of the surface of the charge on the blast furnace is the same when pouring both iron ore materials and coke, they are distributed along the radius of the blast furnace 60 independently of each other. At the same time, it becomes possible to form ore and coke ridges in one radial zone. Usually, the angle of slope of iron ore materials on the blast furnace is greater than the angle of slope of coke. This results in the ore ridge being more concentrated than the coke ridge. To reduce the ore load and increase gas permeability in the area of the highest concentration of iron ore charge, it is necessary that the coke ridge be more concentrated. For this purpose, when loading the iron ore charge onto the blast furnace, it is necessary to purposefully stretch the ore ridge along the radius of the blast furnace, and insert the coke ridge on a short segment of the radius.

The implementation of the method is illustrated by drawings, where Fig. 1, 2 shows the loading of the blast furnace, which ensures an increase in gas permeability in the area of the ore ridge, with a tray loading device, and Fig. 2, C shows the loading of the blast furnace, which provides an increase in the gas permeability in the area of the ore ridge, cone loading device.

The loading of the blast furnace, equipped with a tray loading device, is carried out as follows (Fig. 1). Loading system: dА»1и1ККиой, where 9, 10, 11 are tray tilt stations, corresponding to the angle relative to the vertical axis of 42.27; 45.67; 497 (Industrial operation of the tray loading device 7/0 blast furnace / A. A. Bachinin, A. V. Rybtsov, V. P. Lozovy, etc. / Stal, - 1992, - Mo 5, - P. 13 - 18) ; A - skip of iron ore material (sinter), K - skip of coke.

Two skips of iron ore materials 1 are loaded into one of the batch hoppers of the loading device, for example, the left hopper 2. After reaching the specified filling level, the batch gate is opened. From the left hopper, iron ore materials are poured onto the tray 4, and from there onto the surface of the batch 5 on the furnace. The tray rotates 7/5 around the vertical axis at a speed of 8 rpm, which provides a relatively uniform circumferential distribution of the charge. During the pouring of the iron ore charge, the tray changes the angle of inclination relative to the vertical axis from 42.2 to 49" (from the 9th to the 11th station). The trajectory of the fall of ore materials 6 changes from steeper to more positive.

Iron ore materials are located in the form of a distributed ridge 7 on a segment of the radius of the furnace near the walls of the furnace. After emptying the left hopper 2, the batch valve C is closed. Simultaneously with the unloading of the iron ore charge from the left hopper onto the furnace, two coke skips 9 are loaded into the right hopper 8. After reaching the specified filling level, the charge valve 10 of the right hopper is opened. Coke is poured onto a tray that rotates at a constant angle of 45.67 (10th station) and along the trajectory 11 is poured onto the furnace. It is located on the surface of the backfill in the form of a concentrated annular ridge 12. After pouring all the coke, the charge valve 10 is closed. At the same time as the coke is supplied to the furnace from the right hopper, the charge is loaded into the left hopper 2. After that, the process of loading the charge to the furnace is repeated. As a result of carrying out the described loading procedure, a radial distribution of iron ore charge 13 and coke 14 is formed with maximum concentration at the furnace walls. At the same time, the maximum ore load of 15, respectively, the minimum gas permeability of the charge is formed in the intermediate zone (Fig. 2).

At the walls of the furnace, in the area of concentration of iron ore materials, the gas permeability is higher and a more developed gas flow will pass through it. Due to the increase in the amount of reducing gas in the area of the largest amount of ore charge, the indirect recovery will be more developed, the development of direct recovery will decrease, which will ensure a decrease in coke consumption. When loading the charge with a tray loading device, the area with the maximum concentration of iron ore material can be located at some distance from the walls of the furnace. Thus, when using the loading system AA"vKK/with a change in the angle of inclination of the tray to - 3 of 5 of the vertical axis from 36.67 (b station) to 40.67 (8 station) distributed ore and concentrated coke "And ridges will be located in the intermediate zone. At the same time, the effect of increasing the gas permeability of the ore ridge zone will also be achieved.

The loading of the blast furnace, equipped with a conical loading device, is carried out in the following way (Fig. 30. The loading system of the DALKK. Two skips of iron ore 70 materials 17 are loaded onto the large cone 16. After reaching the measure, the large cone descends at a reduced speed. A significant part of the material has time fall through a narrow gap between the contact surfaces of the cone and the bowl 18. Due to the resistance of the edges of the contact surfaces, the charge first falls along steep trajectories 19. As the large "" cone descends, the width of the gap increases, the resistance of the edges decreases, and the charge falls onto the furnace all the way more positive trajectories 20. As a result, iron ore material is placed on the blast furnace in the form of a distributed ridge 21 on a section near the walls of the furnace. After lowering to the full stroke, the large cone rises to its initial position. After that, two skips of coke are loaded onto the large cone (on a chair. -1 not shown.) After reaching the measure, the large cone 16 descends to full stroke at normal speed.

Most of the coke is poured onto the blast furnace along the positive trajectory 22 and is located at the walls in the form of (ee) a concentrated ridge 23. The large cone rises to the entry position, and the loading of the charge is repeated. yuyu 50 The method of loading the blast furnace, which provides an increase in gas permeability in the area of the ore ridge, with the help of a conical loading device, was tested on a sectoral model of the furnace of the blast furnace 62, made on a scale of 1: 10. As charge materials, agglomerate of size 1 - Zmm and coke were used Z - mm. The surface of the backfill with an angle of inclination of 22" was simulated with iron ore particles larger than 1 mm in size. The backfill level was 0.15m (1.5m - nature). First, agglomerate was loaded onto the surface of the backfill. The large cone was lowered to a full stroke of 0.075m (0.75m - nature ) in 4.8 s (15 s - nature), which is twice as long as the usual time for its descent.

P" with knives on b equal-sized radial zones. Materials were extracted from each zone, dispersed and the mass of agglomerate in each zone was weighed. Loading coke was produced similarly. The time for lowering the cone was 2.4 s (7.5 s - nature), which corresponds to the usual time for lowering a large cone to a full stroke. The largest mass of agglomerate 60 24 (Fig. 4) and coke 25 are concentrated in the peripheral zone. However, the maximum ore load 26 is shifted to the intermediate zone. Due to the reduction of the ore load in the zone of concentration of iron ore materials, the gas flow and the amount of reducing gases will increase. Increasing the development of side reduction reactions will allow to reduce coke consumption.

The method of loading the blast furnace, which provides an increase in gas permeability in the area of the ore 65 ridge, with the help of a tray loading device, was tested on the operating blast furnace Mo Z MK "Azovstal" with a useful volume of 1719 m Z. The Adoel1UKKioi loading system was used. After its application, a decrease in the specific consumption of coke by 10 - 13 kg/t of coal was achieved. Despite a slight decrease in the intensity of blast melting, the productivity of the blast furnace increased by 100 t/day.

The expected economic effect from the application of the proposed technical solution will be 0.001 7 10 5 300 " 600 - 1800 thousand hryvnias, where 10 is a reduction in coke costs, kg/t of coal;

Z00 - cost of 1 x coke, UAH.; 600 - annual productivity of the blast furnace, thousand tons

Claims (2)

The formula of the invention 1. The method of loading the blast furnace, which includes the separate supply of coke and iron ore charge, which differs in that the iron ore charge is loaded with annular combs distributed along the radius of the blast furnace, and coke - with concentrated annular combs in the middle part of the iron ore comb. 2. The method of loading a blast furnace according to claim 1, which differs in that when using a tray loading device, the iron ore charge is loaded at no less than three consecutive stations of the slope of the distribution tray, and coke is loaded at one station of the slope of the distribution tray, corresponding to the middle station during loading iron ore charge. C. The method of loading the blast furnace according to claim 17, which differs in that when using a conical loading device, the iron ore charge and coke are loaded when the specified filling level is reached, and when loading the iron ore charge, the large cone is lowered more slowly than when loading coke. " (ав) сч (ее) in "I - and t" - and (ee) ko "2 bo b5