SU834136A1 - Method of drying blast furnace bottom - Google Patents

Description

(54) METHOD FOR DRYING THE BLOCKS OF A DOMAIN FURNACE

I

The invention relates to ferrous metallurgy, and more specifically to the drying of a masonry blast furnace.

A known method of drying the blast furnace floor of the products of the combustion of coke oven gas. For this purpose, at a height of about two meters above the gill, an insulated metal shutter is installed. Circular gas pipelines with holes drilled in them directed vertically or vertically or at an angle of 45 to the vertical are arranged concentrically under the ceiling on the bottom. A coke oven gas is supplied to each gas pipeline through a cast iron cell. Air for gas combustion is supplied by a fan through a slag tavern. Combustion products are released through the cast iron doorway 1.

Partial penetration of gaseous combustion products, which have high temperatures, through the leak-tightness of the heat-insulated ceilings makes it difficult to work in the upper horizons of the furnace. The surface surface teteration fluctuates within 300-450C, which does not ensure complete removal of moisture from the seams of the floor of the floor, lined with alumina refractory bricks, and also does not provide

complete removal of volatile substances from carbon pastes using carbon blocks for laying the bottom. In addition, the known method does not provide the ability to supply the required amount. heat

The closest in technical essence and the achieved result to the proposed is the method of combined drying of the bottom with the help of electric heaters and transducer electric

- burning furnaces by laying electric heaters of iichrome strips under the bottom row of laying of the bottom, which includes immediately after the end of its laying. At the end of the laying of each pore, it is dried with mobile ovens. After

calculations 700-800 mm of the furnace bed on the upper floor of the stack are placed electric heaters similar to those laid under the bottom row of floor {2.

The disadvantages of this method are

However, the fact that electric heaters do not cover the entire area of the bottom area, as a result of which the necessary and uniform heat supply is not provided, and large expenses of electric power are required.

The purpose of the invention is to increase the efficiency of the process by providing the water with the required amount of heat for drying and increasing the durability of the bottom.

The goal is achieved by the fact that in the method of drying the blast furnace floor, which includes heat supply using electric heaters and hot blowing, additional heat is applied by pouring liquid iron on the bottom to a height H 1 / 3-1 / 2 the distance between the surface the bottom and the axis of the iron notch, and the iron on the bottom is poured in layers from 1/10 to 1/20 N in height with an interval between layer fillings from 30 to 60 minutes.

Cast iron on the bottom is poured from the tank through a tuyere or summer vent hole. The method is carried out as follows. The required volume of cast iron is determined to fill it with a base to a height of N. The height of each layer of cast iron must be 15-20 mm, which corresponds to 1 / 10-1 / 20 of the total height N. A pre-cast iron container, such as a cast-iron ladle, raises and they turn over the help of the lifting and tilting mechanisms of the blast furnace mounting beam and through a temporary chute installed on the subdomain of the blast furnace and leading to the tuyere or pilot hole, the cast iron is poured onto the blast furnace bed, dried beforehand. with electric heating, gas burners, hot air and prepared for the first iron intake.

A temporary gutter passing through a tuyere or letting hole will cause a stream of cast iron to fall in the center of the hearth of a blast furnace with a fall height of 0.7 - 0.8 m. Before casting, 5 5 X steel sheets are placed on the bottom. 500 X 500 mm, in order to avoid destruction of laying by the stream of the first cast iron layer.

The periphery of the bottom is lined with heat-insulating bricks at the height of the cast iron layer, which are easily destroyed later by thermal expansion of the pig-iron monolith formed.

Every 30–60 min, the operation of pouring iron from a iron dipper bucket is repeated until the required volume of heat cast on the cast iron required for the conditions of supply of heat is reached, after which the temporary trough is repaired.

The method was tested on a model of blast furnace bed, where heat transfer conditions were studied, the thicknesses of cast iron layers, the time of their hardening and cooling were determined.

When the thickness of the iron layer is less than 15 mm, it is not possible to cover them with the entire required surface, since

the thickness of the layer tends to decrease as it moves away from the loading point, and the required heat supply is not provided.

With a thickness of the pig iron layer over 20 mm

a very high temperature is created on

surface of the floor, causing overheating

refractory mass to depth. up to 20 mm

and therefore its destruction.

The use of layers 15–20 mm thick is also advisable in view of their relatively fast hardening, darkening of the surface and reduction of heat loss due to radiation into the working space of the furnace. A layer of cast iron with an average thickness of 17 mm solidifies completely within 5 minutes and cools down to a dark cherry color (600 ° C) within 10 minutes after filling.

30 minutes after casting, the surface temperature of the iron casting 17 mm thick is 70 ° C.

Heating of refractory aluminosilicate bricks laid on the plate and playing the role of the upper layer is characterized by the following data: 5 minutes after casting, the brick is heated to a depth of 30 mm, where its temperature reaches 50 ° С, and 10 minutes later, the brick surface is on the opposite side casting iron, also has a temperature of 50 ° C.

Temperature equalization pa of the entire surface of the bricks occurs 30 minutes after the start of the experiment; the surface temperature is 40 ° С.

Thus, after 30 minutes, the brick, directly facing the surface of the iron casting, absorbs and evenly distributes the heat perceived by it throughout its mass. This circumstance determines the minimum interval between successive casting of iron on the base. An increase in the interval between fills over 60 minutes leads to a decrease in the intensity of the heat flow. q The casting of BiTOporo cast iron of equal volume leads to the welding of two layers, rapid temperature equalization over the entire surface of the casting formation. External signs of casting 5 minutes after the second layer is cast: the color of the entire surface5; ti - cherry red heat, the metal is completely hardened. No further darkening of the refractory mass of the bricks is observed. This is due to the shielding effect of the first cast iron layer. , Q. The method of building up layers of cast iron makes it possible to obtain a predetermined temperature over: the surface of the floor and maintain its long time; the bottom is heated uniformly over its entire surface, which ensures favorable conditions for the base 5 of the base over its entire thickness. Regulation of the surface temperature of the bottom layer is achieved by varying the intervals between the fillings and the mass of the cast iron.

Example. The diameter of the hearth of the blast furnace is 11 m. The distance from the bottom surface to the axis of the cast iron notch is 600 mm. The total height of the layers of cast iron H 1/3 V H0 200 mm.

The area of the forest filled with cast iron is 95 m.

The height of the cast iron bed is 1/10 N, which is 20 mm.

The bed volume of the cast iron is 95 X 0.02 1.9 m3.

The weight of one cast iron is equal to 1.9 X X 7.15 13.6 t, where 7.15 is the density of cast iron, t / m.

The total number of layers of cast iron

600 (W 10 layers

The total weight of the cast iron is 13.6 x X 10 136 tons.

The bream is pre-dried using electric heaters and hot blowing.

Cast iron is poured through a tuyere hole. 13.6 tons of iron are poured onto each layer 20 mm high.

Just pour 10 layers with an average interval between fillings 45 minutes.

The duration of the entire operation is 10 X 45 450 minutes.

Thus, during one work shift (7.5 hours), all operations are performed to dry the blast furnace bed.

The proposed method for drying blast furnace floor allows for supplying the required amount of heat during the drying process and increasing the resistance of the floor in comparison with the known method.

Claims (2)

1.Galemin I.M., Gorokh A.V. Carbon lining of blast furnaces. Metallurgizdat, 1964. 2.Brail B.N. The development of blast-furnace production at the Kuznetsk Metallurgical Combine. Metallurgizdat, 1961.