SU1296819A1 - Smoke-diverting channel of double-earth steelmaking furnace - Google Patents

Abstract

The invention relates to the field of ferrous metallurgy, in particular, to the design of the smoke exhaust duct of a two-bath steel-smelting furnace. The purpose of the invention is to increase the degree of cooling of flue gases and the separation of molten entrainment, the flue gas duct of a two-bath steel-smelting furnace contains slags 2, heat exchangers 3 with an upper part 5 connected on one side with slag 2, and on the other with a flue 14. pseudoconductive gas distribution yards are installed (L

Description

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the grids 4 with nozzles 7, on which the nozzles 9 are installed with an axially symmetric gap with respect to the grate 4. The grate 4 is filled with a nozzle - intermediate dispersed coolant; air is fed through the grate 4 1 under the grate 4 to create a fluidized bed. Convective superheaters 10 are placed in this layer. Compressed air is supplied through nozzles 7, which by means of nozzles 9 creates a spouting nozzle. When moving

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The invention relates to ferrous metallurgy, in particular, to the design of the smoke exhaust duct of a two-bath steel-smelting furnace.

The purpose of the invention is to increase the degree of cooling of flue gases and the separation of molten entrainment.

FIG. Figure 1 shows the smoke pipe of a two-bath steel-smelting furnace; figure 2 - section aa in figure 1.

The flue pipe of the two-bath steel-melting furnace has on each side of the furnace vertical channels 1, slags 2, heat exchangers 3 divided by height by pseudorating gas distribution grids 4 on the upper part 5 and the sub-grate without grates 5 equipped with nozzles 1 connected to the pipeline 8 compressed air supply, on which the nozzles 9 with a gap relative to the grid 5 are axisymmetrically mounted. The nozzle of the heat exchanger is designed as an intermediate dispersed heat carrier located on gas-distributing grill 5. Convective steam superheaters 10 are placed above the grill 5, partially placed in a layer of the intermediate dispersed heat transfer fluid. 2, and on the other hand, with smoke flue 14, equipped with gates 15 and connected to a common flue flue 16. On the common smoke flue 16, a boiler is installed in series to the top and to the bottom and back to the nozzle layer is heated by the heat of the flue gases flowing over the packing layer, and thereon is deposited molten ash. Additional separation of molten entrainment in a fluidized fluidized bed nozzle reduces the drift of the smoke exhaust pipe and labor costs for its cleaning, reduces furnace downtime for repairs and increases its annual capacity, 1 s.p. f-ly, 2 ill.

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heat exchanger 17, dust cleaning 18, smoke exhauster 19, flue pipe 20, channel 21 connecting the suction side of the fan 13 to the common flue gas 16 after the waste heat boiler 21 or piercer 18. Heat exchanger 3 has a channel 22 to drain off the excess fluidized bed particles.

The smoke duct works as follows.

Fig. 1 shows the smoke path in a position where the melt is blown with oxygen by oxygen in the left bathtub B of a steelmaking furnace. At this time, in the right bath B, the operations of filling, heating of the charge and pouring of cast iron are performed. In bath B, carbon monoxide burns in bath B, heating the mixture. The flue gases enter the right vertical channel I, then into the slag 2 where the larger particles of molten entrainment are separated, pass in the upper part 5 of the heat exchanger 3 above the fluidized bed located on the fluidizing gas distribution grid 4.

Before starting the furnace, a nozzle consisting of granule or sand with a size of 2-5 mm is poured onto these grids and the fan 13 is turned on, which through the duct 11 supplies air under the grate, creating a fluidized bed on the grate 4, in which convective steam superheaters 10. Compressed air is supplied through nozzles 7, which creates a vacuum in the lower part of nozzles 9, sucks the nozzle into them, and then throws it up into the flue hectare flow

call, to form a gushing fluidized bed. When moving up and falling back into the bed, the nozzle is heated by the heat of the flue gases and melted entrainment is deposited on it, solidifying on the surface of the particles.

The pads into the fluidized bed, heated particles release heat to the purged air and through the convective steam superheaters 10 of the steam-water mixture or water, steam, gas, and so on. Due to the fact that hardened slag ash falls into the nozzle layer, the bed height increases. through the dividing wall into the slag 2 or out through the channel 22. The flue gases cooled to this temperature through the flue 14 through the open gate 15 enter the common flue 16, are further cooled in From the waste heat exchanger 17, they are cleaned of dust in a piezer cleaning 18 and exhausted through a smoke exhauster 19 through a smoke pipe 20 to the atmosphere.

It is possible to connect the suction of the fan 13 with the channel 21 to the common flue 16 after the waste heat boiler 17 or dust cleaning 18. In this case, flue gases with a temperature of about 200 ° C are supplied under the grate 4, which increases the heat generation in the convection superheaters 10.

When purging the melt in the chamber B, open the gates 12 and 15 on the left side of the furnace and close on the right. The flue gas duct works in a similar way; only the flue gases in the furnace move from right to left and are discharged along the left half of the dual part of the tract.

The magnitude of the heat transfer coefficient to the heat-receiving surfaces of the convective superheaters 10 in the fluidized bed is an order of magnitude greater than in the gas stream. At the same time, in the gas flow with a molten entrainment, the heat-absorbing surfaces of the superheaters are covered with slag from

in the fluidized bed

the surfaces are always clean, since they are cleaned by particles moving in the bed, therefore the size of heating surfaces in the bed, which is necessary for a given cooling, is several times smaller than in the gas flow. Intensive heat transfer from the flue gases to the fluidized bed particles is provided by a significant amount

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their total surface, which is greater, the smaller the particle size.

As a result of intensive cooling of the flue gases by the fluidized bed particles, there is no need to cool them with water injection. This reduces the amount of flue gases removed through the path by 20-25%.

Equipping the fluidizing lattice with nozzles having axially symmetric nozzles mounted on them with a gap relative to the lattice and connected to the compressed air pipeline allows organizing the flowing movement of the fluidized bed nozzle in its entire height and intensifying the heat removal from the gases to the nozzle and then to the heating surfaces and the deposition of molten entrainment on the nozzle particles.

In practice, in the flue gases behind the waste-heat boiler, the oxygen content is 10–15%, and their temperature is about 200 ° C. Therefore, the connection of the fan’s suction to the boilers after the waste-heat boiler leads to an increase in heat generation by the heat-absorbing surfaces located in fluidized bed as a result of an increase in its temperature. -Containing oxygen is enough to burn carbon monoxide, and the required increase in the amount of

Comparing these gases with air is useful for creating a large volume of fluidized bed.

Claims (2)

1. A flue gas duct of a two-bath steel-smelting furnace containing successively placed vertical ducts, slags, heat exchangers, air ducts for supplying fan air, flue hogs, exhaust fans and chimneys, characterized in that, in order to increase the degree of cooling of flue gases, 512 call and separation of molten entrainment, the heat exchanger is made in the form of a pseudo-oxygenation gas distribution grid, on which the intermediate dispersed heat carrier is placed; air, while fluidizing i-asopacnpe Editor S. Lisin Compiled by L. Sharapova Tehred L, Oleinik Proofreader M.Sharoshi Order 763/40 Circulation 544Subscribe VNIIPI USSR State Committee for inventions and discoveries P3035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4 The divider lattice is provided with nozzles connected to the compressed air supply pipe, on which nozzles are axially mounted with a gap relative to the lattice. 2. The tract of pop. 1, which differs from the fact that it is equipped with a convective superheaters located above the fluidizing gas distribution grid and partially placed in the layer of the intermediate dispersed heat transfer fluid. BUT 6 8 Sh