SU1212635A1 - Arrangement for withdrawing gases from arc furnace - Google Patents

Description

one

The invention relates to devices for the removal of process gases from arc furnaces and can be used in the electric steelmaking industry of metallurgy and machine-building industry.

The aim of the invention is to increase the efficiency of removal of process gases from the furnace by reducing the inflow of atmospheric air into the gap between the arched and fixed nozzles.

The drawing shows a device for removing gases from an arc furnace, a general, view.

The device contains a water-cooled vault 1 and stationary 2 branch pipes installed with a gap, for example, 250 mm for a 100-ton electric furnace. The arch nozzle 1 fixed immobile above the orifice 3 in the roof A of the furnace has a flange 5 mounted at a distance S (O, 2-0.4) d from its output section, where d is the diameter of the arch nozzle. The stationary nozzle 2 has an elliptical cross-sectional shape, with its horizontal diameter greater than the vertical one, and the cross-sectional area of the stationary nozzle is 3-3.5 of the cross-sectional area of the arched nozzle. For air leaks to cool the process gases at the stationary nozzle 2, a nozzle 6 is installed with an adjusting flap 7. To adjust the gap between the vault 1 and the stationary 2 nozzles, the device has a movable coupling 8, which is pushed onto the vault nozzle by means of an actuator 9,

The device works as follows

In the working position of the furnace, the movable coupling 8 slides over the arch pipe 1, Id. The process gases are drained from the furnace through the opening 3 in the arch 4 of the furnace, the arch 1 and the stationary 2 branch pipes. The inflow of air through the gap between the coupling and the arched nozzle, as well as the pressure loss in this area with the 8 position lowered, is minimal, which ensures efficient removal of gases from the furnace. The air needed to cool the gases is sucked through pipe 6 and

ten

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2126352

adjustable in accordance with the temperature of the gases using the valve 7, the elliptical shape of the stationary nozzle 2 and the movable coupling 8 allows, without disrupting the tightness of the connection of the nozzles, to incline the furnace by 2-3 °, necessary, for example, to download slag. When metal is drained into the ladle, the coupling is retracted, and a gap is created between the coupling and the coupling nozzle, which is necessary for the free movement of the tap elbow at large inclination angles of the furnace.

The optimality of the chosen flange installation distance on the roof pipe and the movement of the coupling on the roof pipe was determined as a result of laboratory studies of gas suction devices of 100 and 200-ton arc steel-smelting furnaces.

In the course of research, the costs of gases discharged from the furnace G, the flow of sucked air through the gap between the branch pipe and the coupling G and the coefficient of local resistance of the joint and stationary connection node at different distances S of the flange installation on the branch pipe and 1 mezzanine coupling and flange of the arched pipe.

The research results, t, e,

value and depending on 4

 S / d at 1 0.1 d const lead 20

25

thirty

in tabl, 1,

T a.b l and c a I

40

S / d T GI / G, I

0.0 0.1 0.2 0.3 0.4 0.5 0.6-0.8

From the above data (Table 1) it can be seen that the value of the relative

air flow, sucked into the gap, and the coefficient of local resistance at, 2d are large enough. With the values of S (O, 2-0.4) d, the values are reduced by about two times, the resistance coefficient is about four times.

The increase, 4 has a relatively weak effect on the decrease in the values of Gi / Gt and, So, at, 5, the values of and $ are 0.7 and 0.47, respectively (Table 1), and at S / d, 0.6-0.8 , 69-0.68 and 0.46-0.45, i.e. remain almost the same as with S / d O, 4. At the same time, a further increase in S / d of 0.4 leads to the need to increase the horizontal portion of the arched nozzle and increase its dimensions and weight, and an increase in the clutch stroke is also required, which is also associated with an additional complication of the design. In this connection, an increase in S / d of more than 0.4 is impractical.

The values of Gj / Gi and / s in dependence 1

from 2 at S 0,3d are given in table.

Table 2

1 / d

j

The data show that when, 1d air leaks in

Editor A.Vorovich Order 694/16

Compiled by A. Filippov Tehred O. Netse

Corrector

Circulation 572Subscribe

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Branch PPP Patent, Uzhgorod, st. Project, 4

212635

the stationary nozzle and the local resistance coefficient of the node of the nozzle connection node are sharply increased. Therefore, the movement of the coupling to the arch pipe should provide a distance between the coupling and the flange of the arch pipe no more than O, Id.

Installing the flange on the roof pipe at a distance S (0.2-0.4) d

10 and the movement of the movable coupling over distance, Id provides a sharp decrease in air inflow through the gap between the nozzles and the pressure loss in the suction device. So, for the conditions of OO- Ton-. arc steelmaking furnace from which it is necessary to divert 23 thousand process gases,

air leaks into the gap between the pipes are reduced from 96 thousand nm / h (known device) to 48 thousand nm / h using the proposed design of the gas suction device.

Due to the fact that during periods of operation of the furnace (melting, purging, refining), the movable coupling completely closes the gap between the branch and stationary nozzles, air leaks into the path and pressure losses in this node are sharply reduced. This significantly increases the efficiency of removal of process gases from the furnace and reduces unorganized dust and gas emissions from the electrode holes and the working window of the electric arc furnace. Reducing the amount of exhaust gases and pressure losses reduces capital and operating costs. Hai gas transportation and cleaning.

The annual economic effect expected from the implementation of the invention at a 200-ton arc furnace is 35.5 thousand rubles.

Proofreader G. Reshetnik

Claims (1)

DEVICE FOR REMOVING GASES FROM .CENTURAL FURNACE, containing a vault pipe with a flange, a stationary pipe mounted on it with a gap and a movable sealing sleeve, characterized in that, in order to increase the efficiency of process gases removal from the furnace by reducing the suction of atmospheric air into the gap between vault and stationary pipes, the flange of the vault pipe is installed from the outlet section of the vault pipe at a distance equal to 0.2-0.4 of the diameter of the vault pipe, and the movable coupling in the working polo enii furnace tube pulled down over the crest, the distance between the sleeve flange end and arched pipe diameter does not exceed 0.1 arched tube. S SU .. „1212635> 1 1212635