JPH07286216A - Sintering method by waste gas circulation and waste gas circulation equipment - Google Patents

Abstract

PURPOSE:To increase a sintering speed and to improve a sintering yield and productivity by supplying ordinary-temp. air in a range where pressure drop increases according to progression of sintering at the time of sintering by waste gas circulation using a lower suction sintering machine. CONSTITUTION:Raw materials 1 to be sintered are packed into a sintering pallet 8 by a surge hopper 2 and are sintered while this pallet 8 is moved. At this time, the waste gases are sucked into the sintering layer within a range where the progression ratio of sintering in the sintering layer in the pallet 8 in a moving direction is >=0 to <=10% and >=50 to <=100%. Air is sucked into the sintering layer in a range where the progression ratio of the sintering layer is over 10% and below 50%, by which the sintering is executed. A front part circulating gas hood 14a and a rear part circulating gas hood 14b are disposed respectively before and behind the sintering machine exclusive of the rage where the ratio of the machine length in the longitudinal direction of the machine is over 10% and bellow 50%, by which the waste gases from a window box 9 are introduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sintering method and equipment for producing a sintered ore which is a raw material for producing hot metal in a blast furnace or the like.

[0002]

2. Description of the Related Art A schematic process of a conventional exhaust gas circulation sintering method is shown in FIG. The sintering raw material 1 is conveyed to the surge hopper 2 and charged into the sintering pallet 8 via the chute 3 to form the raw material filling layer 6. The layer thickness of the raw material filling layer 6 is 600 mm. The coke in the surface layer portion of the raw material packed bed 6 is ignited in the ignition furnace 7.

The wind box 9 is divided into a mining side and a mine side, and a flue gas on the mine side or a circulating flue gas in which exhaust gas and air are mixed is circulated in a sintering layer on the mine side.
Is sucked in to burn the coke in the raw material-filled layer 6, and the combustion heat sequentially sinters the raw material from the upper layer to the lower layer. The mine ore side burns the coke in the raw material packed bed 6 while sucking air, and the combustion heat sequentially sinters the raw material from the upper layer to the lower layer.

Further, Japanese Patent Laid-Open No. 50-19605 discloses an exhaust gas circulation sintering method in which hot air discharged from a cooler and exhaust gas from an exhaust ore portion are sucked into a sintering layer. Further, JP-A-53-58903 describes an exhaust gas circulation sintering method in which, when the exhaust gas of the exhaust ore part is circulated to the first half of sintering, a part of the exhaust gas is also circulated to the latter half of the sintering. ing.

[0005]

In the conventional sintering method, as shown in FIG. 4, the raw material layer 6a decreases as the sintering cake 6c is formed while the sintering reaction zone 6b moves downward. The pressure loss per unit sintered layer shows a larger value in the order of the sinter cake 6c, the raw material layer 6a, and the sintering reaction zone 6b depending on the bulk density. However, the thicknesses of the sinter cake 6c, the raw material layer 6a, and the sintering reaction zone 6b differ depending on the progress rate of sintering. Therefore, Sinter Cake-6
pressure loss P ₁ of c, the pressure loss P ₂ of the sintering reaction zone 6b, the total pressure loss HP which is the sum of the pressure loss P ₃ of the raw material layer 6a will show different values depending on the degree of progress of sintering.
The transition of this total pressure loss HP is shown in FIG. 5, but it shows a tendency that the sintering progress ratio increases in the range of 10% to 50%.

Here, the rate of progress of sintering is 0 immediately after ignition.
%, And the point at which the sinter ore in the slag discharge section falls from the grate of the sinter pallet is 100%. The ratio of the machine length in the longitudinal direction of the sinter machine is 1 from the point immediately after ignition to the point where the sinter in the discharged slag falls from the grate of the sinter pallet.
00%.

Since the total pressure loss HP has a high value in the range of 10% to 50% in the progress of sintering, the amount of exhaust gas passing through the sintered layer in the range is reduced. In the exhaust gas circulation sintering method, the acidity concentration of the gas sucked into the sintered layer is low,
Further, since the temperature of the gas is high, the oxygen supply amount is further reduced as compared with the case of sucking air. For this reason, the sintering is delayed, the sintering time is extended, and the productivity is reduced. Further, in the stagnation part of the sintering, the sintering reaction zone 6b is maintained for a long time, so that the sintering reaction zone 6b is excessively melted, the bulk density of the formed sinter cake 6c increases, and the air permeability of the sinter cake 6c deteriorates. Air becomes difficult to reach the lower raw material layer 6a of the sinter cake 6c having a high bulk density, the combustion of coke is hindered, the sintering becomes further stagnant, and the sinter cake 6c becomes weak, and the yield (product of 5 mm lumps or more) is obtained. The yield) is decreased.

The above problems cannot be solved even by the exhaust gas circulation sintering method described in JP-A-50-19605 or JP-A-53-58903. Therefore, it is an object of the present invention to provide an exhaust gas circulation sintering method and an exhaust gas circulation facility that accelerate the sintering rate, improve the yield, and improve the productivity.

[0009]

According to the exhaust gas circulation sintering method of the present invention, in the exhaust gas circulation sintering method using a lower suction sintering machine, the sintering progress ratio of the sintered layer in the longitudinal direction of the sintering pallet is 0% or more. Exhaust gas is sucked into the sintered layer within the range of 10% or less and 50% or more and 100% or less, and air is sucked into the sintered layer when the sintering progress ratio of the sintered layer is more than 10% and less than 50%. The exhaust gas circulation sintering method is characterized in that Further, the exhaust gas circulation equipment of the present invention is the exhaust gas circulation equipment of the lower suction sintering machine, wherein the proportion of the machine length in the longitudinal direction of the sintering machine is 0% or more and 10% or less and 50% or more 1.
The exhaust gas circulating equipment is characterized in that a circulating gas hood is provided on the upper portion of the sintering pallet within the range of 00% or less.

[0010]

[Function] In the case where the sintering progress ratio in which the total pressure loss is high is more than 10% and less than 50%, room temperature air is sucked,
Since the acidity concentration is not lower than that of the exhaust gas and the temperature of air is lower than that of hot air at room temperature, a large amount of oxygen can be supplied to the sintered layer, which increases the sintering rate. Therefore, the stagnation of the sintering can be prevented, the sintering time does not extend, and the sintering reaction zone 6
The maintenance time of b does not become long, the bulk density of the sinter cake 6c does not decrease, and the decrease in yield is eliminated. Yield is improved because heat is added to the sintered layer because high-speed exhaust gas is circulated in the sintered layer before and after the sintering progress ratio in which the total pressure loss becomes high exceeds 10% and less than 50%. To do.

When the ratio of the machine length in the longitudinal direction of the sintering machine is more than 10% and less than 50%, the sintering progress ratio is 10%.
The total pressure loss HP becomes high in the range of more than 10% and less than 50%, which corresponds to the range of more than 50% and less than 50%.

[0012]

Embodiment 1 FIG. 1 shows an embodiment of the exhaust gas circulation equipment of the present invention.

The sintering raw material 1 is conveyed to the surge hopper 2,
600 m after being charged into the sintering pallet 8 through the chute 3
The raw material filling layer 6 of m was formed. The coke in the surface layer portion of the raw material packed bed 6 was ignited in the ignition furnace 7. Wind box 9
The exhaust gas of 210 ° C. and oxygen concentration of 19.5% on the mine side is supplied to the front circulation gas hood 14a and the rear circulation gas hood 14b.
It was connected to the exhaust gas introduction pipe 13 of.

The front circulation gas hood 14a has a ratio of the machine length in the longitudinal direction of the sintering machine from the point immediately after ignition of the ignition furnace 7 to 10% or less, that is, the upper layer 60 mm of the raw material filling layer 6 of 600 mm is fired. By the time the knotting progresses,
The rear circulation gas hood 14b has a ratio of the machine length in the longitudinal direction of the sintering machine of 50% or more, that is, 60%.
From the time when 300 mm sintering proceeds from the upper layer of the 0 mm raw material filling layer 6, the ratio of the machine length in the longitudinal direction of the sintering machine is 85% or less, that is, 600 mm of the raw material filling layer 6
The range was from the upper layer to the time when 510 mm of sintering proceeded. A flow rate adjusting valve 21 is installed in the exhaust gas introduction pipe 13, and a front circulation gas hood 14a and a rear circulation gas hood 1 are installed.
The amount of exhaust gas to 4b was adjusted.

When the front circulation gas hood 14a and the rear circulation gas hood 14b were not installed, air was sucked and sintered in a range where the total progress of pressure was high and the sintering progress ratio was more than 10% and less than 50%. Therefore, the stagnation of the sintering can be prevented, the sintering speed can be increased, and the conventional sintering time of 35.1 minutes to 33.5
And the yield is 80.7 from the conventional yield of 75.3%.
Improved to%. Therefore, the productivity is 29.4 of the conventional one.
It was increased from T / D / m ² to 35.1T / D / m ^2.

[0016]

[Embodiment 2] FIG. 2 shows another embodiment of the exhaust gas circulation equipment of the present invention.

The sintering raw material 1 is conveyed to the surge hopper 2,
600 m after being charged into the sintering pallet 8 through the chute 3
The raw material filling layer 6 of m was formed. The coke in the surface layer portion of the raw material packed bed 6 was ignited in the ignition furnace 7. A hot air blower 23 and a hot air tube 24 are used to supply hot air of 250 ° C. from a cooler 22 for cooling the discharged high temperature sintered ore to the front circulation gas hood 1.
4a and the rear circulation gas hood 14b were supplied from the exhaust gas introducing pipe 13.

The front circulation gas hood 14a has a ratio of the machine length in the longitudinal direction of the sinter machine of 10% or less from the point immediately after ignition of the ignition furnace 7, that is, the upper layer 60 mm of the raw material filling layer 6 of 600 mm is baked. By the time the knotting progresses,
The rear circulation gas hood 14b has a ratio of the machine length in the longitudinal direction of the sintering machine of 50% or more, that is, 60%.
From the time when 300 mm sintering proceeds from the upper layer of the 0 mm raw material filling layer 6, the ratio of the machine length in the longitudinal direction of the sintering machine is in the range of 100%, that is, 600 mm of the raw material filling layer 6
The range was from the upper layer to the time when 600 mm of sintering proceeded. A flow rate adjusting valve 21 is installed in the exhaust gas introduction pipe 13, and a front circulation gas hood 14a and a rear circulation gas hood 1 are installed.
The amount of exhaust gas to 4b was adjusted.

When the front circulation gas hood 14a and the rear circulation gas hood 14b were not installed, air was sucked and sintered in the range where the progress rate of sintering where the total pressure loss was high was more than 10% and less than 50%. Therefore, the stagnation of sintering can be prevented, the sintering speed can be increased, and the conventional sintering time is 35.1 minutes to 32.7.
The yield is reduced to 81.0 from the conventional yield of 75.3%.
Improved to%. Therefore, the productivity is 29.4 of the conventional one.
It was increased from T / D / m ² to 36.8T / D / m ^2.

[0020]

According to the present invention, since the sintering rate is increased and the yield is also improved, the productivity is improved as compared with the conventional exhaust gas circulation sintering method.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of an exhaust gas circulation facility of the present invention.

FIG. 2 is a diagram showing another embodiment of the exhaust gas circulation equipment of the present invention.

FIG. 3 is a diagram showing a process of a conventional exhaust gas circulation sintering method.

FIG. 4 is a diagram showing the progress of sintering in a conventional sintering method.

FIG. 5 is a diagram showing changes in total pressure loss of a sintered layer.

[Explanation of symbols]

 1 Sintering Raw Material 2 Surge Hopper 3 Chute 4 Flooring Hopper 5 Flooring 6 Raw Material Packing Layer 6a Raw Material Layer 6b Sintering Reaction Zone 6c Sinter Cake 7 Ignition Furnace 8 Sintering Pallet 9 Windbox 10 Circulating Gas Dust Collector 11 Circulating Gas Blower 12 Circulating gas flue 13 Exhaust gas introducing pipe 14 Circulating gas hood 14a Front circulating gas hood 14b Rear circulating gas hood 15 Dust collector 16 Desulfurization device 17 Blower 18 Chimney 21 Flow rate control valve 22 Cooler 23 Hot air blower 24 Hot air tube

Claims (2)

[Claims] 1. In an exhaust gas circulation sintering method using a downward suction sintering machine, a sintering progress rate of a sintered layer in a longitudinal direction of a sintering pallet is 0% to 10% and 50% to 100%.
Exhaust gas is sucked into the sintered layer within the following range, and air is sucked into the sintered layer for sintering in the range where the sintering progress ratio of the sintered layer is more than 10% and less than 50%. Exhaust gas circulation sintering method. 2. In the exhaust gas circulation equipment of a lower suction sintering machine, the ratio of the machine length in the longitudinal direction of the sintering machine is 0% or more and 1 or more.
An exhaust gas circulation facility, characterized in that a circulating gas hood is provided above the sintering pallet within the range of 0% or less and 50% or more and 100% or less.