SU1035838A1 - Arc electric furnace electrode aperture gasodynamic sealing - Google Patents

Description

This invention relates to electrothermal and can be applied to arc furnaces. A known structure for sealing the electrode holes of an arc furnace is a steel ring duct open to the side of the electrode. An air stream is generated tangentially into the duct, which creates a rotating annular Notok. This flow prevents flue gases from escaping from the electrode holes C 13. However, this design has a number of drawbacks. Fan speed air with low speeds and low pressure are used to lock the electrode gap. At the same time, there is no complete elimination of flue gas emissions. In addition, under conditions of high temperatures, uncooled metal ducts deform, fade and completely go out of order often after 5-1 days of work. An additional reason for the failure of such seals is the occurrence of an electric arc between the electrode and the metal CMM duct lying on the roof. The box is also destroyed due to exposure to gases from the working area and radiation of hot electrodes. The closest to the proposed technical essence is the hydrodynamic sealing of the electrodes of the electric arc furnace, made in the form of a collector with nozzles mounted in the direction of the furnace space at an acute angle to the horizontal axis of the collector mounted on the arch and enclosing the electrode located in the arch annular gap kilns t23 The disadvantage of such a seal is its low resistance, since due to the small distance between the electrode and the gas-dynamic seal there is a possibility Nost arose novena electric arc and destroy any last. When the collector burns out, the efficiency of its operation deteriorates and gas emission is not completely eliminated. The purpose of the invention is to increase the stability of bone compaction and its efficiency. The goal is achieved by the fact that 8 gas-dynamic sealing of the electrode holes of an electric arc furnace made in the form of a collector with nozzles directed towards the furnace space at an acute angle to the horizontal axis of the collector mounted on the roof and covering the electrode located in the roof of the furnace with an annular gap, the collector nozzles are installed relative to the surface of the roof and the surface of the electrode at a distance equal to 0.2-0, the diameter of the electrode, the axis of the nozzles are directed in plan in the middle of the annular gap a, and said angle is 20-50. FIG. 1 shows the gas-dynamic seal of the electrode hole of an arc furnace, a section; in fig. 2 seal, general plan view. The furnace pipe 1 at a distance of 0.20, the diameter of the electrode 2 installed in the roof with an annular gap 3 from the surface of the electrode and at the same distance from the roof surface is installed a metal collector C with nozzles S and a pipe 6 for supplying gas to the collector 4. The axis of the nozzles 5 are directed in plan b to the middle of the gap between the electrode 2 and the electrode hole 3 and down at an angle 0 20-50 to the horizontal axis of the collector. Install the seal on the vault 1 on the supports 7 wrapHHbix to the sealer collector C. The device works as follows. Gas is supplied to the seal from the workshop line by a flexible metal hose — to a distribution manifold, which is installed on a water-cooled vault ring, and from it — metal pipes through the arch of the furnace to collector k through nozzles 6. Steam can be used as a gas to seal the electrode hole; nitrogen or other inert gas. Inert gas, the exit from the nozzles of the collector with a high flow rate, enters the electrode gap and prevents the release of highly dust-free smoke gases. With appropriate gas flow rates, emissions are completely eliminated, thereby preventing the atmosphere of the workshop from contamination. In addition, the elimination of dust and gas emissions helps to increase the resistance of electrode holders and other

equipment located above the roof.

Due to the fact that the seal is at a distance of 0.2-O from the surface of the electrode, the diameter of the electrode and the effect of intense radiation from the working space and the electrode is weakened, its resistance is high.

The optimality of the chosen seal distances from the roof and the electrode surface, equal to 0.2-0, the diameter of the electrode, was determined as a result of industrial tests. It was noted that as the collector approaches the electrode surface, i.e. as the size of the reservoir itself decreases, its life decreases. When installing the collector from the surface of the electrode at a distance less than 0, the diameter of the electrode 2 increased thermal effect from the electrode and the working space. There have been cases of deformation. collectors, reflow nozzles. In addition, cases of clogging of nozzles were often observed, which led to a decrease in the efficiency of the seal. .

As the distance from the electrode surface to the collector increases to more than 0, the diameters of the electrode increase the inflow of cold ambient air, which negatively affects the thermal operation of the furnace. To get steam jets into the electrode gap, it is necessary to position the collector at a distance of 0.2-0 from the surface of the roof, equal to the electrode diameter.

With a distance from the collector to the arch less than 0.2 the diameter of the electrode of the gas jet at a given angle of inclination of the nozzles do not fall into the electrode gap, thereby disrupting the operation of the sealing device. Increasing this distance more than Q, k of the electrode diameter increases the consumption of gas of the energy carrier for sealing the electrode hole and the inflow of atmospheric cold air into the furnace increases. When the nozzles are located, when their axes are directed in the plan into the middle of the gap between the electrode and the edge of the electrode hole, the gas jets flowing from the nozzles reliably close the entire electrode gap. When the axes of the nozzles are displaced to the electrode, the locking ability of the sealant deteriorates and, in addition, jets flowing out at high speed, such as steam, adversely affect the durability of the electrode.

When the nozzle axes are displaced towards the walls of the electrode hole, the efficiency of the seal operation deteriorates, as the jets stick to the walls of the hole, the entire area does not overlap, and knocking around the electrode appears. The optimal angle of inclination of the nozzles 20-50 to the horizontal is determined on a cold hydraulic model of an arc furnace, made of organic glass on a scale of 1: 5. Compressor air was used as the gas sealing the electrode gap.

The table shows the data on the simulation of gas flow in terms of industrial furnace conditions.

1300

15

The data show that the most rational angles are 800

on the nozzles to the horizontal are 20 and 50. For values of angles less than

1035838

20 and more than 50 emissions from edect native holes are not found.

The expected economic effect of the implementation of the invention is 1-025 rubles.

The implementation of the invention is also of great social importance.

it allows, without significant capital and operating costs, to improve the working conditions of the staff and drastically reduce air pollution.

Claims (1)

GAS-DYNAMIC SEALING OF ELECTRODE HOURS OF AN ARC ELECTRIC FURNACE, made in the form of a collector with nozzles directed towards the furnace space at an acute angle to the horizontal axis of the collector mounted on the arch and covering the electrode located in the arch of the furnace with an annular gap, characterized in that increase the sealing resistance and work efficiency, the collector with nozzles is installed relative to the surface of the arch and the electrode surface at a distance equal to 0.2-0.4 of the electrode diameter, nozzle axis aligned in the middle of the annular gap, and the specified angle is 20-50 °. Fig.! * 1035838 2