RU1788973C - Method of cooling blast furnace charging device - Google Patents

Abstract

SUMMARY OF THE INVENTION: when cooling gas is supplied to the drive housing of the distribution element and then discharged into the cavity of the blast furnace, cooling gas is directed from the drive housing to the outer surface of the housing, and a circular curtain is formed in the cross-sectional plane above the distribution element from the gas discharged into the furnace. . 1 ill.

Description

The invention relates to ferrous metallurgy and can be used to cool the charging devices of blast furnaces.

A known method of cooling a blast furnace loading device, comprising supplying clean cold blast furnace gas at a pressure higher than the pressure in the furnace, into an annular cavity formed by an additional funnel, a large cone and a bowl.

But the implementation of the known method is accompanied by a large consumption of pure blast furnace gas discharged through the slit gap between the large cone and the bowl. With multi-meter diameters of a large cone and a bowl located in the top spaces of modern blast furnaces, the conditions of overheating of certain parts of the cooled elements, especially the central zone of the cone, are maintained. The heat exchange between the cold gas passing through the slit of the large cone and the bowl is accompanied by simultaneous withdrawal

heat from both overheated areas and areas with a relatively lower temperature, i.e. It contributes only to some smoothing of the temperature difference of the cooled elements of the furnace, and does not eliminate the thermal stresses of the cone material in the gas-shut contact sieve. In addition, when opening a large cone of a blast furnace for unloading charge materials onto the top, i.e. after the leveling gap between the cone and the cup disappears, unfavorable conditions for local cooling of the surfaces of the cone and the cup (funnel) arise at the points of supply of pure blast furnace gas, which causes them to deform and increase the gas-abrasive wear of the contact surfaces

The closest in technical essence and the achieved result to the claimed invention is a method of cooling the boot device, which consists in forcing cold nitrogen into the drive housing of the distribution tray located on the dome part

with C

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blast furnace and serving as a cooled separation unit between the furnace and the loading device, followed by the release of nitrogen into the furnace through constant slotted gaps between the rotating elements of the tray.

However, the known method has the following disadvantages. Since the cooled drive housing of the tray covers the estrus through which the charge material is released onto the tray, the central zone of the domed part of the blast furnace is open for entry of the warmest blast furnace gas flows having a maximum temperature in the zone along the central vertical axis of the blast furnace. The nitrogen leaving the annular slit gaps of the tray drive forms a double cylindrical jacket, which, being lowered to the upward flows of the top gas, is distributed, forming a gas funnel, which contributes to the capture of the upward flows with an increased area of the central zone of the top of the furnace and an organized entrance heated up to a high the temperature of the top gas flows through the central heat in the gas-cutting part of the loading device. With an increase in the power of the blast furnace to ensure its productivity, the diameter of the central chute increases, which determines the increase in the diameters and widths of the slotted gaps of the tray drive, while the nitrogen consumption for cooling the tray drive increases and, accordingly, the thermal effect on the gas-cutting part increases. The loading device through an increased area cross section of central estrus. With an increase in the cross section of the central estrus, the intensity of thermal shifts acting on the gas shut-off elements of the charging device after the release of each portion of the charge material increases. The high frequency of thermal shifts and significant temperatures in the installation zone of the gas shut-off elements reduce their durability and make it necessary to stop the lock hopper for repairs to replace gas shut-off valves, which is accompanied by a decrease in the productivity of the blast furnace.

The aim of the proposed method is to increase the cooling efficiency of the charging device of the blast furnace and to reduce the consumption of cooling gas due to the multi-stage use of its cooling ability.

The goal is achieved in that in a method for cooling a loading device of a blast furnace, comprising supplying cooling gas to the drive housing of the distribution element and discharging gas into the cavity of the blast furnace from the drive housing

gas is directed to the outer surface of the housing, and a circular curtain is formed from the gas discharged into the furnace in the plane of the cross section above the distribution element.

0 The formation of a continuous circular curtain from the cooling gas discharged into the furnace in the plane of the cross section above the distribution element allows the charging device to be cut off from the direct heat exposure of the gas flows of the central part of the blast furnace top cavity after each portion of the charge materials is released to the top. In addition to the additional use, in comparison with the prototype, of the kinematic energy of the gas discharged into the furnace during the formation of a circular curtain, the proposed method allows to increase the heat transfer efficiency during secondary

5 using nitrogen to cool and cut off the housing of the rotary distribution element from the thermal effects of the dome of the blast furnace and to cool the outer surface of the housing

0 of his drive. The combination of the stepwise repeated use of the thermal and dynamic properties of the cooling gas in the proposed method allows to reduce the nitrogen flow rate and eliminate the intense heat exchange cycles for the gas shut-off elements of the loading device.

The implementation of the claimed method of cooling the blast furnace loading device is illustrated by the device shown in the attached diagram.

A device for implementing the proposed method comprises a lock hopper 1 mounted on an intermediate funnel 2, which is mounted on the dome part of the blast furnace 3. The intermediate funnel 2 is equipped with transverse hollow beams 4, interconnected in the center of the funnel through the chamber 5. The chamber 5 is divided by a seal 6 into two parts, forming cavities A and B. In cavity A, the drive housing 7 of the blade rotary distributor of charge 8. is mounted. The rotary charge distributor 8 is connected to drive 7 by shaft 9, on which mounted 5 van di ck 10. On the outer end holes of the beams 4, plugs 11 are installed, which are equipped with a seal 12 of the intermediate shaft of the actuator 7 and a high-pressure fan 13 with a valve 14. A valve 15 is installed on the outlet fitting in the cylindrical part of the beam 4. The housing of the actuator 7 is equipped with a discharge a cold gas pipeline 16 and a reflector 17 mounted on the gas outlet fitting 18. In the end parts of the beams 4, outlet pipes 19 are installed that are connected to the annular collector 20, connected through the pipe 21 to the cavity Yu B cameras 5. On the manifold 20 is mounted fitting 22 for supplying steam.

The proposed method of cooling the boot device is carried out by pumping cold gas (nitrogen) through a pipe 16 into the drive housing 7 installed in the cavity A of the chamber 5. After partial heat exchange between the parts inside the drive housing 7, cooling gas is discharged through the nozzle 18 onto the outer surface of the drive housing 7 due to the reflector 17, after which the total gas stream entering the chamber 5 is sent to the exhaust pipes 19, dividing the cooling gas into parts according to the number of cavities of the beams 4. The tightness of the internal of the transverse beams 4 and the cavity A of the chamber 5 is provided with plugs 11, seals 12 and 6, as well as valves 14 and 15. From the pipelines 19, cooling gas through the annular manifold 20 is supplied through the piping 21 to the cavity B of the housing 5, from where through the annular gap between the shaft 9 of the rotary distributor of the charge 8 in the lower hole of the chamber 5 enters the slotted gap C, formed by the outer end surface of the chamber 5 and the disk 10. By means of the slotted gap C from the cooling gas having an excess pressure relative to the top pressure about gas in the cavity of the blast furnace 3, a circular curtain is formed in the plane of the cross section above the distribution element 8.

The gas screen formed by the circular curtain prevents the entry of central hot top gas flows into the cavity of the intermediate funnel 2, thereby preventing unacceptable heating of both the funnel itself and the gas shut-off elements of the lock hopper 1 of the blast furnace loading device. In the absence of nitrogen or other cooling gas in the power supply system of the blast furnace, or in the case of a long interruption (more than 0.5 hours) in the supply of cooling gas, the option of combined cooling of the loading device by means of steam and air is used. In this embodiment, the discharge pipes 19 are closed. The cut-off screen of the circular curtain is formed by supplying steam to

the collector 20 through the nozzle 22 with the subsequent release of steam through the slot gap C. In this case, the valves 14, 15 are opened, and the actuator body 7 and the cavities of the transverse beams 4 and the chamber 5 are cooled by supplying compressed air through the pipe 16.

In case of insufficient dehydration of the compressed air used to cool the boot device, especially at low temperatures in winter, it is possible to cool the boot device by turning on the high-pressure fan 13. B

in this case, the pipe 16 is disconnected from the compressed air network. The consumption of cooling gas (nitrogen) when using the first variant of the proposed method is from 500 to 2000 cubic meters per hour, depending

from the size of the outlet of the intermediate funnel 2, characterizing the performance of the loading device, the amount of thermal energy discharged from the drive 7, the maximum thermal values

parameters of the center of the top, with an end slotted gap C made in the range from 2.5 to 6 mm. provides thermal operation of the drive 7 within 50-70 degrees, and the gas temperature in the upper

cavity of the intermediate funnel 2, under the cone of the lock hopper 1 within 100-120 degrees, with a temperature difference in the diametrically opposite points of the contact gas sealing surfaces

cone and bowl hopper 1, comprising 5 degrees. For example, for a blast furnace with a volume of 2000 cubic meters, equipped with a loading device with an outlet diameter of the funnel 2 equal to 1600 mm, power

drive 7 rotates the charge distributor 70 kW and the maximum temperature in the center of the top within 700-800 degrees, the nitrogen flow rate is 1500 cubic meters per hour with a gap gap of 4 mm.

When using the second and third variants of the proposed method, the flow rate of steam to create a screening curtain of the funnel 2 is equal to the flow rate of nitrogen and equal to the flow rate of air supplied to cool the drive 7, the internal cavities of the chamber 5 and the beams 4, and the static pressure of the fan 13 is from 300 to 500 mm.v.st.

If it is necessary to stop the blast furnace with gas afterburning at the top, the loading device is thermally protected by supplying air to the discharge pipe 16 (or 22), from which a circular cutting curtain is formed to prevent overheating of the loading device elements from the burning gas torch.

Implementation of the proposed method for cooling the blast furnace loading device will ensure long-term operation of the loading device regardless of the adverse operating and shutdown conditions of the blast furnace. At the same time, sequential stepwise selection of the cooling ability of the gas during its passage through the individual nodal units of the loading device in combination with the use of the residual kinetic energy of the gas to create screen protection of the loading device can increase the efficiency of beneficial use of each

milk units of gas volume and reduce its consumption by 30%.

Claims (1)

SUMMARY OF THE INVENTION A method of cooling a blast furnace loading device, comprising supplying cooling gas to a distribution element drive housing and discharging gas into a blast furnace cavity, characterized in that, in order to increase the efficiency of the cooling process and reduce the flow of cooling gas, gas is directed from the drive housing They are lifted onto the outer surface of the housing, and a circular curtain is formed from the gas discharged into the furnace in the plane of the cross section above the distribution element.