KR100286686B1 - Furnace wall inserting type reduced iron charging system and reduced iron charging method using the same - Google Patents

Abstract

PURPOSE: A furnace wall inserting type reduced iron charging system is provided which continuously charges the reduced iron into the upper part of a coal fluidized bed inside a smelting reduction furnace as restraining flying of fine reduced iron by high speed upward flow formed at the smelting reduction furnace, and a reduced iron charging method using the same is provided. CONSTITUTION: The furnace wall inserting type reduced iron charging system comprises a plurality of reduced iron supply units consisting of a reduced iron discharge pipe(11) which is inserted into a prereduction furnace(2) finally reducing iron ore so as to discharge the finally reduced iron into the outside, a pressure equalized weighing bin(12) weighing the reduced iron discharged through the reduced iron discharge pipe(11) and a reduced iron supply pipe(13) supplying the reduced iron from the pressure equalized weighing bin(12) to a smelting reduction furnace(1); a reduced iron discharge and supply controller(20) controlling discharging and supplying of the reduced iron; and a pressure controller(30) controlling a pressure of the pressure equalized weighing bin(12), wherein a first airtight valve(11b) and a second airtight valve(13a) are installed on the reduced iron discharge pipe(11) and the reduced iron supply pipe(13) respectively, load cells(12a) which are electrically connected to the reduced iron discharge and supply controller(20) and measure the amount of the reduced iron are equipped at the pressure equalized weighing bin(12), a gas introduction pipe(12b) for introducing a gas for pressure controlling is connected to the pressure equalized weighing bin(12), a pressure control valve(12c) for controlling pressure is equipped at the gas introduction pipe(12b), and a pressure gauge(1a) for measuring a pressure in a coal fluidized bed is installed at the smelting reduction furnace(1).

Description

Furnace wall insertion type reduced iron charging device and method

1 is an example of a furnace wall-mounted reduced iron device in accordance with the present invention

2 is a detailed view of a no-buck insert-type reduced iron charging device in accordance with the present invention

3 is an exemplary configuration diagram of a three-stage fluidized bed pre-reduction device equipped with a furnace wall inserting-type reduced iron charging device of the present invention.

<Explanation of symbols for main parts of drawing>

1: melt reduction furnace la: pressure gauge

1b: Coal distribution distributor 2: Preliminary reduction reactor

11 reduced iron discharge pipe 12 equal pressure basis bin

l3: reduced iron supply pipe 20: reduced iron discharge and supply controller

30: pressure controller

The present invention relates to a furnace wall insert type reduced iron charging apparatus and a reduced iron loading method using the same in the powdered reduced iron produced in the preliminary reduction in the molten reduction steelmaking process consisting of a fluidized bed pre-reduction reactor and a melt reduction reactor. The present invention relates to a furnace-loaded reduced iron charging apparatus for charging reduced iron into the upper part of a carbonaceous fluidized bed in a molten reduction reactor while suppressing the scattering of finely-reduced iron from high-speed ascending flow formed in the upper portion of the molten reduction reactor, and a method for charging reduced iron using the same. .

Typically, as a method of producing iron by reducing iron ore, there is a method of using a blast furnace and a method of melting iron ore reduced in a shaft furnace in an electric furnace.

In the method for manufacturing molten iron by the blast furnace process, a large amount of coke is used as a heat source and a reducing agent, and iron ore is charged into the blast furnace in the form of sintered ore to improve breathability and reducibility.

For this reason, the current blast furnace method requires a coke oven facility and a sintered ore manufacturing facility for carbonizing strong coal briquettes. Therefore, the blast furnace method requires not only enormous investment cost but also energy consumption process, and coking coking raw material coking coal has a small amount of coexistence in the world and is ubiquitous locally.

On the other hand, the reduction of iron ore by the shaft furnace requires a pretreatment step of pelletizing iron ore, and since it uses natural gas as a reducing agent and a heat source, it can be commercialized only in an area where natural gas can be easily supplied. Due to its shortcomings, the melt reduction method of producing molten iron from powdered iron ore using coking without using coke has attracted attention as a new steelmaking method.

In such a melt reduction method, a method in which iron ore reduced in a preliminary reduction furnace is usually charged into a molten reduction reactor and melt-reduced with molten iron is adopted.

In the preliminary reduction furnace, the iron ore is reduced in a solid state before the iron ore is melted, and the charged iron ore should be reduced by contact with hot reducing gas generated in the molten reduction furnace.

This reduction process is classified into a moving bed or a fluidized bed type according to the contact state of iron ore and reducing gas. The granular iron ore having a large overwhelming distribution is charged into a reduction furnace, and a reducing gas is sent through the dispersion plate at the bottom to reduce the flow of iron ore. Fluidized bed is known as a suitable way to reduce ferrous ore.

On the other hand, when the powdered reduced iron discharged from the fluidized bed pre-reduction reactor is introduced into the molten reduction reactor, medium / fine reduced iron is scattered together with the rapid rise of reducing gas discharged from the melt reduction reactor. By increasing the concentration of heavy and fine reduced iron in the flue gas in the melt reduction furnace by increasing the concentration of the cyclone, which is a gas purification equipment of flue gas generated in the melt reduction furnace, the collection rate is reduced, and the deposits on the gas distribution plate in the reduction furnace are also reduced. As a result, the holes of the dispersion plate are blocked, and the scattering loss is increased, resulting in a decrease in the recovery rate of reduced iron in the molten reduction reactor.

In order to solve this problem, US Patent No. 4,978,387, Korean Patent Application No. 87-12076, and Japanese Patent Laid-Open No. 62-224620 use a transport gas and a burner as a method of injecting finely-reduced iron into the melt reduction reactor. have. However, in this method, not only a huge amount of gas is required to transport the finely-reduced iron from the fluidized bed outlet to the burner, but also the burner is severely worn around by the finely-reduced iron, and the burner needs to be replaced frequently during long-term use. In addition, it is pointed out as a problem that the energy consumption of the overall transport gas at room temperature is additionally consumed.

In addition, Japanese Patent Laid-Open Nos. 1-116035, 1-119631, 1-247513, and 1-257514 are mixed with iron ore and coal, and a hardened briquette manufactured by hot forming or press molding. It has been proposed to use a briquette as feedstock to a melt reduction reactor. However, in these methods, a molding machine for hardening the mixture of reduced iron and coal must be installed separately between the fluidized-bed reduction furnace and the molten reduction reactor, and even coarse iron ore capable of gravity injection can be mixed with coal together with the medium / fine iron ore. As the particle size distribution of the reduced iron is increased, the porosity of the molding increases, so that the compressive strength of the hardened briquette is weakened, and the capacity of the molding machine and the requirements of the carbon material are excessive.

In addition, Austrian Patent AT 1234/95 proposes a method of gravity charging finely-reduced iron while blowing oxygen through a charging pipe connected to a fluidized bed outlet and an input destination in a melt reduction reactor. However, in order to realize this method, it is difficult to develop a durable material that can be used for a long time in a high temperature and abrasion atmosphere, and there is a possibility of occurrence of an abnormality in the downstream area. What can't be done is pointed out as a flaw, which faces technical challenges in design and material development.

The present invention has been proposed to solve the above problems of the conventional methods, by continuously reducing the iron on the top of the carbonaceous fluidized bed in the melt reduction reactor while suppressing the scattering of reduced iron due to the high-speed upward flow formed on the top of the melt reduction reactor The purpose of the present invention is to provide a furnace-loaded reduced iron charging apparatus and a reduced iron charging method using the same.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated.

The present invention relates to a molten reduction apparatus including a preliminary reduction reactor and a molten reduction reactor, the reduced iron discharge tube being inserted into the preliminary reduction reactor for finally reducing iron ore to discharge the reduced reduced iron to the outside, the reduced iron discharge tube A plurality of reduced iron supply apparatuses comprising a balance pressure balance bin for weighing the reduced iron discharged through and a reduced iron supply pipe configured to supply reduced iron from the balance pressure balance bin to the molten reduction reactor; Reduced iron discharge and supply controller for controlling the discharge and supply of reduced iron; And a pressure controller configured to control the pressure of the equalization balance bin, wherein the reduced iron discharge pipe and the reduced iron supply pipe are provided with a first airtight valve and a second airtight valve, respectively; The balance pressure bin is electrically connected to the reduced iron discharge and supply controller and is provided with a load cell for measuring the reduced iron amount, and a gas introduction pipe for introducing a pressure regulating gas; The gas introduction pipe is provided with a pressure control valve for adjusting the pressure; And it relates to a furnace wall insert-type reduced iron charging device is provided with a pressure gauge for measuring the pressure in the coal ash flow bed in the melt reduction reactor.

In addition, the present invention in the charging of the final pre-reduced reduced iron in the molten reduction reactor by using the above-described reduced iron charging device, the pressure control valve and the second hermetic valve is shut off to equalize the pressure of the preliminary reduction reactor and the equalization basis weight bin Discharging the finely-reduced iron to a balance balance bin by gravity; Measuring the amount of reduced iron charged in the balance balance bin and shutting off the first hermetic valve when the amount reaches the target amount; Adjusting the pressure balance valve by a pressure regulating valve in a state in which the first air tight valve and the second air tight valve are shut off so that the pressure of the pressure balance bin is higher than the pressure of the carbon ash flow in the melt reduction reactor; Supplying reduced iron to the carbonaceous flow in the melt reduction reactor by opening the second hermetic valve if the pressure in the equalization balance bin is higher than the pressure in the carbonaceous fluid phase in the melt reduction reactor; And it relates to a reduced iron charging method comprising the step of performing the above steps repeatedly with a time difference for each reduction charging device.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

As shown in FIG. 1, the furnace wall inserting-type reduced iron charging device of the present invention is configured to charge the reduced iron finally reduced in the final preliminary reduction reactor 2 for final preliminary reduction of iron ore into the molten reduction reactor 1. .

Reduced iron supply device 100 of the present invention is provided with a reduced pressure iron (12) to equalize the reduced iron to reduce the iron supply to the molten reduction reactor (1) to reduce the reduced iron in the preliminary reduction furnace (2) for the final reduction of iron ore The apparatus 100 includes a reduced iron discharge and supply controller 20 for controlling reduced iron discharge and supply, and a pressure controller 30 for controlling the pressure of the equalization balance bin.

The reduced iron supply device 10 is inserted into the wall of the preliminary reduction path (2) for the final reduction of iron ore, the reduced iron discharge pipe 11 is configured to discharge the reduced reduced iron to the outside, discharged through the reduced iron discharge pipe (11) And a reduced iron supply pipe 13 configured to supply reduced iron to the molten reduction reactor 1 from the equalized basis weight bin 12 for weighing reduced iron. The reduced iron supply apparatus is formed in plural.

The reduced iron discharge pipe 11 is provided with a first hermetic valve 11b. As shown in FIG. 1, the reduced iron discharge pipe 11 is preferably provided with a discharge device 11a such as a screw conveyor for discharging the reduced iron from the preliminary reduction reactor 2.

The equalization balance bin 12 is provided with a load cell 12a electrically connected to the reduced iron discharge and supply controller 20 and measuring a reduced iron amount, and supplying gas for supplying a pressure regulating gas such as nitrogen or exhaust gas. A pipe 12b is connected, and the gas introduction pipe 12b is provided with a pressure regulating valve 12c.

One end of the reduced iron supply pipe 13 is connected to the equalization basis weight bin 12, and the other end of the reduced iron supply pipe 13 is inserted into a side wall of the melt reduction reactor 1, and a second hermetic valve 13a is provided.

The reduced iron discharge and supply controller 20 is electrically connected to the discharge device 11a, the load cell 12a, the first hermetic valve 11b, and the second hermetic valve 13a.

As shown in FIG. 2, the pressure controller 30 is provided in the melt reduction reactor 1 to measure the pressure in the pressure control valve 12c and the carbonaceous fluid bed 1b of the melt reduction reactor. It is electrically connected with the pressure gauge 1a.

A fluidized bed pre-reduction reactor to which the reduced iron charging apparatus of the present invention can be more preferably applied is shown in FIG.

That is, as shown in Figure 3, the fluidized bed pre-reduction path to which the present invention can be preferably applied is generated by burning the exhaust gas passing through the first reduction reactor 3 to the iron ore charged from the charging hopper (5) A fluidized bed preheating furnace 4 for preheating using heat to make; A first reduction furnace 3 for primary reduction of the iron ore preheated in the preheating furnace 4; A second wet vibration damper (7) for purifying the exhaust gas passed through the preheating furnace; A second reduction furnace 2 for finally reducing iron ore primarily reduced in the first reduction furnace 3; And a first wet oscillator 6 for purifying the exhaust gas passed through the first and second reduction paths.

Hereinafter, a method of continuously charging the reduced iron using the reduced iron charging apparatus of the present invention configured as described above will be described.

As shown in FIGS. 1 to 3, the reduced preliminary reduced iron in the preliminary reduction reactor 2 is discharged by an exhaust device 11a such as a screw conveyor or gravity discharged by an overflow. At the time of discharge, the pressure reducing valve 12c and the second hermetic valve 13a are closed to equalize the pressure in the preliminary reduction path 2 and the equalization balance bin 12 so that the finely reduced iron is equalized in the lower portion by gravity. It enters the basis weight bin 12, and the amount entered is monitored by a load cell l2a installed in the equalization basis weight l2, and when a specified amount is reached, a signal is sent to the iron oxide discharge and supply controller 20, and this controller 30 Stop the discharge device (11a) and close the first airtight valve (11b), and move to the reduced iron charging device (10) consisting of the discharge device and the equalization balance bin specified in the following order to repeat the same operation. do.

On the other hand, in order to charge the differential reduction iron introduced into the equalization balance bin 12 into the melt reduction reactor, first, the first and second hermetic valves 11b and 13a installed at the front and rear ends of the equalization balance bin 12 are closed, and The pressure in the carbonaceous material fluid bed 1b of (1) is measured by the pressure gauge 1a, and the pressure controller 30 so that the pressure in the balance pressure balance bin 12 is a certain amount higher than the pressure of the carbon material fluidized bed 1b. And the pressure regulating valve 12c. Preferably, the pressure of the balance balance bin is about 0.1 bar higher than that of the carbonaceous fluidized bed. At this time, when the pressure in the balance balance bin 12 is higher than the pressure of the carbonaceous fluid bed 1b, the second hermetic valve 13a in the reduced iron supply pipe 13 is opened to start charging into the molten reduction reactor 1. In addition, the pressure reduction as the finely-reduced iron is discharged is automatically compensated by the pressure gauge 1a, the pressure controller 30, and the pressure control valve 12c to maintain a constant pressure at all times.

And, the reduced iron of the fine powder discharged from the equalization balance bin 12 is charged to the upper part of the carbon ash flow of the molten reduction furnace through the reduced iron supply pipe 13, this reduced iron supply pipe 13 as shown in FIG. By inserting into the sidewall refractory of a melt reduction path, a heat resistant structure can be ensured and scattering by a high speed upflow can be suppressed effectively.

In the present invention, by installing a plurality of reduced iron charging device and sequentially controlled, it is possible to charge the reduced iron continuously.

Hereinafter, the present invention will be described in more detail with reference to Examples.

EXAMPLE

As shown in the following (1. a), charging experiments were carried out under the following conditions (1. b) and the charging experiment was carried out to measure the scattering amount, and the results are shown in Table 1 below.

1) Charge test equipment specification and test conditions

end. Melt Reduction Furnace Simulator

Lower diameter: 800 ㎜

-Upper diameter: 1100 ㎜

-Total height: 5500 ㎜

-Charging pipe diameter: 5O ㎜

I. Experimental condition

-Ore size: 0-4 ㎜ (dry)

Gas: air at room temperature

Flow rate: 760 Nm ³ / h / 1520 Nm ³ / h

-Charging pipe length: 0.5m or 1.5m

-Fraction 〈63 μm: 24%

-Fluidized bed height: 1300 mm

2) Charging test result

In Table 1, the scattering rate means the amount that can not be recovered by flying out to the fluidized bed with respect to the total charge amount, it may be expressed as follows.

[Equation 1]

In other words, if the scattering ratio is high, it is not preferable.

As shown in Table 1 above, as a result of charging through the reduced iron supply pipe under the conditions in which the upward flow occurs, the higher the flow rate, ie, the flow rate increased from 760 Nm ³ / h to 1520 Nm ³ / h, the longer the length of the charging tube 4 In the case of, the scattering rate is lower than the experiment 3, it can be seen that scattering suppression is effective. That is, as can be seen in Experiments 1 and 2, when the flow rate is 760 Nm ³ / h, the scattering rate is hardly affected by the length of the charging pipe, but when the flow rate is 1520 Nm ³ / h, the experiments 3 and 4 As can be seen, the long length of the charging tube is effective for suppressing scattering.

As described above, the present invention prevents the backflow of high-temperature furnace gas by keeping the charging pressure constant by using the equalization balance bin and the pressure controller, and inserts a supply pipe into the furnace side wall refractory to reduce fine iron reduced flow rate in the furnace. By charging in the area, it is possible to suppress the scattering by the fast rising gas, stabilize the gravity loading of finely-reduced iron into the melting reduction reactor, and improve the life of the charging pipe by avoiding direct exposure to the high temperature reducing atmosphere in the melting reduction apparatus. In addition, by sequential control using a plurality of charging devices it is possible to stably load the reduced iron of fine powder.

Claims (4)

In the melt reduction apparatus comprising a preliminary reduction furnace and a melt reduction reactor, the reduced iron discharge pipe (11), which is inserted into the preliminary reduction reactor (2) for the final reduction of iron ore to discharge the reduced reduced iron to the outside, and A plurality of equalization basis weight bin 12 for weighing the reduced iron discharged through the reduced iron discharge pipe 11, and a reduced iron supply pipe 13 configured to supply reduced iron from the equalization basis weight bin 12 to the molten reduction reactor 1 Two reduced iron supply apparatuses 10; Reduced iron discharge and supply controller 20 for controlling the discharge and supply of the reduced iron; And a pressure controller 30 configured to control the pressure of the equalization balance bin 12, wherein the reduced iron discharge pipe 11 and the reduced iron supply pipe 13 are respectively provided with a first airtight valve 11b and a second airtight valve. 13a is provided; The equalization balance bin 12 is provided with a load cell 12a electrically connected to the reduced iron discharge and supply controller 20 and measuring the reduced iron amount, and a gas introduction pipe 12b for introducing a pressure regulating gas. Connected; The gas introduction pipe (12b) is provided with a pressure control valve (12c) for adjusting the pressure; And the melt reduction reactor (1) is provided with a pressure gauge (1a) for measuring the pressure in the carbonaceous fluid bed (1b). The furnace wall insert type reduced iron charging device according to claim 1, wherein the reduced iron discharge pipe (11) is provided with a screw conveyor. In the charging of the final pre-reduced reduced iron using the reduced iron charging device of claim 1 in the molten reduction reactor, the pressure reducing valve (12c) and the second airtight valve (13a) is shut off to reduce the preliminary reduction reactor (2) and the equilibrium balance bin Equalizing the pressure of (12) to discharge the reduced iron to the balance balance bin by gravity; Measuring the amount of reduced iron charged into the balance balance bin 12 and blocking the first hermetic valve 11b when the amount reaches the target amount; Pressure control in a state in which the first airtight valve 1lb and the second airtight valve 13a are blocked so that the pressure of the equalization balance bin 12 is higher than the pressure of the carbonaceous fluidized bed 1b of the melt reduction reactor 1. Adjusting the pressure of the balance pressure bin 12 by the side 12c; If the pressure in the equalization balance bin 12 is higher than the pressure in the carbonaceous fluidized bed 1b of the melt reduction reactor 1, the second hermetic valve 13a is opened to supply reduced iron to the carbonized material flow in the melted reduction reactor 1. Doing; And repeating the above steps while giving a time difference for each reduction charging device. 4. The method of claim 3, wherein the reduced iron is discharged by the screw conveyor in the preliminary reduction furnace (2), and the screw conveyor is stopped when the reduced iron amount in the equalization basis weight (12) reaches a target amount.