JPH07103409B2 - Method for preventing blockage of iron ore discharge pipe in preliminary reduction furnace in smelting reduction equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for preventing clogging of a pre-reduction furnace in a smelting reduction facility for iron ore in a discharge pipe of pre-reduced iron ore. Is.

[Prior Art] Iron ore and carbonaceous material are supplied into a converter-type smelting reduction furnace containing an iron bath, and oxygen is blown into the smelting reduction furnace from above through a lance to melt the iron ore. Smelting reduction equipment for iron ore for reducing is known.

FIG. 2 is a schematic explanatory view of such a smelting reduction facility. As shown in FIG. 2, the smelting reduction equipment includes a converter-type smelting reduction furnace 1 and an upper portion of the smelting reduction furnace 1 for pre-reducing the main raw material iron ore supplied into the smelting reduction furnace 1. Fluid tank type pre-reduction furnace 2 and storage tank 3 for main raw materials
And a storage tank 4 for the auxiliary material.

The smelting reduction furnace 1 includes a converter-type furnace body 5, a lance 6 vertically inserted into the furnace body 5 through a furnace opening 5a of the furnace body 5, and a furnace body 5
A stirring gas inlet 7 provided on the bottom wall and side wall of the
The hood 8 covering the furnace port 5a is provided with a main material supply chute 9, an auxiliary material supply chute 10 and a gas discharge port 11.

The preliminary reduction furnace 2 has a large number of nozzles provided in the lower part of the furnace.
It comprises a dispersion plate 12 having 13; a gas blowing chamber 14 formed in the furnace below the dispersion plate 12; and a pre-reduction chamber 15 formed in the furnace above the dispersion plate 12. Gas injection chamber
A gas inlet 16 is provided at 14, and a pre-reduction chamber 15 is provided with a raw material supply chute 17 and a gas outlet 18.

The upper surface of the dispersion plate 12 is formed in a mortar shape, and a discharge pipe 12 for the pre-reduced main raw material is attached to a discharge hole 12a at the center thereof. The discharge pipe 19 is used in the preliminary reduction furnace 2
L-shaped valves 20 and 2 extending downward through the bottom wall of the
It is connected to the chute 9 of the smelting reduction furnace 1 through the base intermediate storage tank 21.

In the gas outlet 11 provided in the hood 8 of the smelting reduction furnace 1,
Gas injection port 16 provided in gas injection chamber 14 of preliminary reduction furnace 2
A gas conduit 22 leading to is attached. A dust collecting cyclone 23 is provided in the middle of the gas conduit 22.

A gas exhaust pipe 24 is attached to the gas exhaust port 18 of the preliminary reduction furnace 2, and a dust collecting cyclone 25 is provided in the middle of the gas exhaust pipe 24.

The storage tank 3 for the main raw material and the raw material supply chute 17 of the preliminary reduction furnace 2 are connected by a duct 26, and the storage tank 4 for the auxiliary raw material and the auxiliary raw material supply chute for the smelting reduction furnace 1 are connected.
A duct 27 is connected between the first and second terminals 10.

A predetermined amount of molten iron 28 was placed in the smelting reduction furnace 1 and the chute 9
Through a pre-reduction furnace 2 to supply the iron ore of a predetermined grain size as a main raw material in the preliminary reduction furnace 2 into the smelting reduction furnace 1, and through a chute 10, carbonaceous material such as coal and a flux as an auxiliary raw material, It is supplied into the smelting reduction furnace 1.

Oxygen gas is blown into the furnace from a furnace port 5a of the smelting reduction furnace 1 through a lance 6 vertically inserted into the furnace body 5, and a gas injection port 7 provided in a bottom wall and a side wall of the furnace body 5.
Through which a stirring gas such as nitrogen gas is blown into the molten iron 28 in the furnace.

Carbon in the carbonaceous material and molten iron 28 supplied into the furnace reacts with carbon gas blown through the lance 6 to generate CO gas, and the generated CO gas is excess oxygen blown through the lance 6. Reacts with gas to form CO ₂ gas. Due to the sensible heat of the CO ₂ gas generated at this time, the iron ore in the molten iron 28 is melted and reduced by the carbon in the carbonaceous material to become molten pig iron.

On the other hand, high temperature exhaust gas generated from the inside of the smelting reduction furnace 1 during refining is discharged from the gas discharge port 11 of the hood 8 and
The gas is blown into the gas blowing chamber 14 of the preliminary reduction furnace 2 through 22. The high-temperature exhaust gas blown into the gas injection chamber 14 is ejected into the preliminary reduction chamber 15 through the nozzle 13 of the dispersion plate 12 and is supplied from the storage tank 3 through the duct 26 and the chute 17 to the preliminary reduction chamber 15. The iron ore 29 of a predetermined particle size therein is preheated and prereduced in a fluidized state.

The iron ore preliminarily reduced in this manner is discharged from the preliminary reduction furnace 2 through the discharge pipe 19 attached to the discharge hole 12a of the dispersion plate 12, passes through the L-shaped valve 20, and the two intermediate storage tanks 21.
Alternately temporarily stored in the smelting reduction furnace 1 and then cut out from the two intermediate storage tanks 21 alternately.

The iron ore supplied into the smelting reduction furnace 1 is, as described above,
Since it is preliminarily reduced, the reduction process can be reduced and the thermal efficiency can be improved.

[Problems to be Solved by the Invention] In the equipment described above, the dispersion plate 12 provided in the preliminary reduction furnace 2 is made of a refractory material. Therefore, the nozzle of the dispersion board 12
Heat is stored by the high-temperature exhaust gas ejected into the pre-reduction chamber 15 through 13.

On the other hand, the iron ore 29 supplied into the preliminary reduction furnace 2 is adjusted to have a grain diameter of 8 mm or less.

Therefore, when the discharge of the pre-reduced iron ore through the discharge pipe 19 from the preliminary reduction furnace 2 is temporarily stopped, the discharge pipe 1 attached to the discharge hole 12a of the dispersion plate 12
Iron ore present inside 9 is heated to about 800 ° C by the heat of the disperser 12.
The material is heated as described above, becomes a semi-molten state, and is sintered.

Due to the iron ore sintered in this way, the discharge pipe 19 is closed, and there arises a problem that the pre-reduced iron ore cannot be discharged from the pre-reduction furnace 2.

Therefore, an object of the present invention is to provide a sintered iron ore to a discharge pipe for discharging the pre-reduced iron ore, which is provided in a dispersion plate of a fluidized tank type pre-reduction furnace in the iron ore smelting reduction facility. It is an object of the present invention to provide a method capable of smoothly supplying pre-reduced iron ore to a smelting reduction furnace without causing blockage due to the above.

[Means for Solving the Problems] The present invention relates to a preliminary reduction furnace having a dispersion disk for pre-reducing iron ore supplied into a smelting reduction furnace, in which a gas for preliminary reduction is jetted, A pre-reduced iron ore that has an upper portion attached to the discharge hole of the outer pipe, is formed of an outer pipe and an inner pipe, and falls through a discharge pipe in which a cooling gas flows in a gap between the outer pipe and the inner pipe. The temperature of the stone is measured by a thermometer provided in the discharge pipe, and the temperature of the iron ore is 700 to 800 ° C., the flow rate of the cooling gas is controlled, and the temperature in the discharge pipe is increased. It is characterized by preventing blockage caused by sintering of iron ore.

Next, the present invention will be described with reference to the drawings. First
FIG. 1 is a schematic vertical sectional view of a lower portion of a preliminary reduction furnace showing one embodiment of the method of the present invention. As shown in FIG. 1, the discharge pipes 19 of the pre-reduced iron ore, the upper ends of which are attached to the discharge holes 12a of the fraction plate 12 in the preliminary reduction furnace 2, are concentric with each other with a predetermined gap therebetween. Outer pipe 19a and inner pipe 19b arranged in
And, for example, nitrogen gas for cooling is blown into the gap between the outer pipe 19a and the inner pipe 19b from the gas blowing port 30 provided in the lower portion of the outer pipe 19a. .
The nitrogen gas blown in this way is discharged into the discharge hole 12a of the dispersion plate 12 from the open upper end of the gap.

A temperature measuring device 31 is attached to a required position on the inner surface of the inner pipe 19b of the discharge pipe 19, and the temperature of the iron ore falling through the inner pipe 19b is measured by the temperature measuring device 31.

The temperature of the iron ore falling through the inner pipe 19b is 700
The flow rate of the cooling nitrogen gas blown from the gas blowing port 30 of the outer tube 19a is controlled so as to be maintained within the range of ℃ to 800 ℃.

As described above, the reason for controlling the temperature of the iron ore falling through the inner pipe 19b within the range of 700 ° C to 800 ° C is as follows. When the temperature of the iron ore exceeds 800 ° C., the iron ore becomes a semi-molten state and sinters in the inner pipe 19b, closing the inner pipe 19b. On the other hand, when the temperature of the iron ore is less than 700 ° C., the preliminary reduction becomes insufficient, and the reduction step in the smelting reduction furnace 1 can be reduced and the thermal efficiency can be improved.

[Operation] As described above, the temperature of the iron ore preliminarily reduced in the preliminary reduction furnace 2 and discharged from the preliminary reduction furnace 2 through the discharge pipe 19 is measured by the temperature measuring device 31 provided in the discharge pipe 19. Discharge pipe so that the temperature of iron ore is 700-800 ℃, measured by
By controlling the flow rate of the cooling gas for cooling 19, the sintering of the iron ore in the discharge pipe 19 does not occur, and the clogging of the discharge pipe 19 is reliably prevented.

[Example] A discharge hole 12a of the dispersion plate 12 of the preliminary reduction furnace 2 having a height of 10 m and an inner diameter of 1 m
Consists of an outer tube 19a and an inner tube 19b, and the inner diameter of the inner tube 19b is 200
An mm discharge pipe 19 made of stainless steel was attached. And
Nitrogen gas for cooling was flowed into the gap between the outer tube 19a and the inner tube 19b to cool it.

Iron ore having a particle size of 0.5 to 8 mm was supplied into the preliminary reduction chamber 15 in the preliminary reduction furnace 2. Then, the iron ore in the pre-reduction chamber 15 was preheated in a fluidized state and pre-reduced by the exhaust gas of about 1,000 ° C. generated from the inside of the smelting reduction furnace 1 ejected from the nozzle 13 of the dispersion plate 12.

Thus, the temperature of the iron ore preliminarily reduced and falling through the inner pipe 19b of the discharge pipe 19 is measured by the temperature measuring device 31 attached to the inner surface of the inner pipe 19b, and the temperature of the iron ore is 700 ° C.
The flow rate of nitrogen gas was controlled to be about 500 Nm ³ / Hr so as to be maintained within the range of 800 to 800 ° C.

As a result, the pre-reduced iron ore is discharged from the inner pipe 19 of the discharge pipe 19.
The iron ore could be smoothly supplied into the smelting reduction furnace 1 through the discharge pipe 19 without being sintered in b.

[Effects of the Invention] As described above, according to the present invention, for discharging the pre-reduced iron ore provided in the dispersion plate of the fluidized-bed type pre-reduction furnace in the iron ore smelting reduction equipment. The discharge pipe is not clogged with the sintered iron ore, and the pre-reduced iron ore can be smoothly supplied to the smelting reduction furnace, which is an industrially useful effect.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional view of a lower portion of a preliminary reduction furnace equipped with the apparatus of the present invention, and FIG. 2 is a schematic explanatory view of smelting reduction equipment. In the drawing, 1 ... Smelting reduction furnace, 2 ... Preliminary reduction furnace, 3,4 ... Storage tank, 5 ... Furnace body, 6 ... Lance, 7 ... Gas inlet, 8 ... Hood, 9,10 …… Chute, 11 …… Gas outlet, 12 …… Distributor, 12a …… Discharge hole, 13 …… Nozzle, 14 …… Gas injection chamber, 15 …… Preliminary reduction chamber, 16 …… Gas inlet, 17 …… Chute, 18 …… Gas outlet, 19 …… Discharge pipe, 19a …… Outer pipe, 19b …… Inner pipe, 20 …… L-shaped valve, 21 …… Intermediate storage tank, 22 …… Gas conduit, 23 , 25 …… dust collection cyclone, 24 …… gas exhaust pipe, 26,27 …… duct, 28 …… iron bath, 29 …… iron ore, 30 …… gas inlet, 31 …… thermometer.

Claims (1)

[Claims] 1. A pre-reduction furnace having a dispersion plate for pre-reducing an iron ore supplied into a smelting reduction furnace, in which a gas for pre-reduction is ejected, the upper part of which is attached to a discharge hole of the dispersion plate. The temperature of the pre-reduced iron ore, which is composed of an outer pipe and an inner pipe and falls through a discharge pipe in which a cooling gas flows in a gap between the outer pipe and the inner pipe, The temperature of the iron ore is 700 to 800 ° C., the flow rate of the cooling gas is controlled, and the blockage caused by the sintering of the iron ore in the discharge pipe is measured. A method for preventing clogging of an iron ore discharge pipe of a preliminary reduction furnace in a smelting reduction facility, which is characterized by preventing