KR101245325B1 - Fluidized reduction furnace and dust removing method for gas distributor thereof - Google Patents

Abstract

Provided is a flow reduction furnace having a function of periodically removing foreign matters attached to the dispersion plate nozzle. The flow reduction furnace according to the present invention includes a reduction furnace body and a dispersion plate and a dispersion plate foreign material removal unit. The dispersion plate is installed under the fluidized bed in the reduction furnace body, and is provided with a plurality of nozzles to distribute and supply the reducing gas to the fluidized bed. Dispersion plate foreign matter removal unit is located outside the main body of the reduction furnace, and includes a charging bin for storing the foreign spectroscopy for removing the foreign matter, and a control valve installed between the outlet of the charging bin and the gas conduit to control the discharge of the fine spectroscopy for removing the foreign matter; When the nozzle is clogged, inject the fine spectroscopy for removing foreign substances into the reducing gas.

Description

FLUIDIZED REDUCTION FURNACE AND DUST REMOVING METHOD FOR GAS DISTRIBUTOR THEREOF}

The present invention relates to a flow reduction furnace of a molten iron manufacturing equipment, and more particularly to a flow reduction furnace having a function of periodically removing foreign matter attached to the dispersion plate nozzle.

Finex (FINEX) molten iron manufacturing equipment is largely composed of a flow reducing furnace for reducing iron ore and a melting furnace having a coal filling layer therein and receives the reduced iron ore to melt it. In the melting furnace, a strong reducing gas containing carbon monoxide (CO) and hydrogen (H ₂ ) as a main component is generated by the combustion of coal, and this is supplied as a reducing gas to the fluidized-bed reactor.

The FINEX process uses coal and iron ore in the first mining process and separates only the granular material. Therefore, it has the advantage of less fuel cost and less environmental pollution compared to the conventional steel blast furnace method.

Since the upper part of the melting furnace is a high temperature operation of about 1,000 ° C. or more, a large amount of dust is generated due to thermal decomposition of the charged coal. Reduction gas of the melting furnace is collected in the hot cyclone more than 90% and put back into the melting furnace, but the uncollected dust is introduced into the flow reduction furnace. It contains approximately 10 to 20 g of dust per 1 Nm ^{3 of} reducing gas flowing into the fluid reduction furnace. Dusts include particulate iron and alkali chlorides, together with pyrolysis residues of coal.

The high temperature reducing gas is supplied to the fluidized bed through the nozzle of the dispersion plate installed in the fluid reducing furnace. Hundreds of gas passage nozzles are installed in the dispersion plate at regular intervals to uniformly distribute the reducing gas into the fluidized bed. However, in the process of reducing gas containing dust, alkali chlorides, etc., present in a liquid or gaseous phase corrode the nozzle surface to roughen the nozzle surface, thereby facilitating foreign material adhesion.

In addition, since the alkali chloride exists in a liquid state at a high temperature and has adhesive force, it is adhered to the surface of the nozzle as foreign matter. Foreign matter adhering to the nozzle surface grows gradually during the operation and, in the worst case, causes nozzle clogging. When a part of the nozzle is blocked, the flow of the reducing gas is concentrated to a part of the region, so that the reducing light is accumulated in the region where the reducing gas is not supplied to form a stagnant layer.

Therefore, the flow reducing furnace cannot perform the function of reducing while flowing iron ore. In this case, there is an inconvenience in stopping the operation of the flow reduction furnace and replacing the nozzle to which the foreign matter is attached. In addition, the ore reduction rate is low because the temperature of the flow reduction furnace must be kept below the melting point of the alkali chloride in order to prevent the alkali chloride from adhering to the liquid phase.

The present invention allows stable operation by periodically removing foreign substances attached to the dispersion plate nozzle without interrupting the operation, and by reducing the fuel cost by improving the reduction rate of ore by increasing the temperature of the reducing gas introduced into the flow reduction furnace. The present invention provides a fluid reduction furnace and a method for removing foreign matter from a dispersion plate in a fluid reduction furnace.

The flow reduction furnace according to the embodiment of the present invention includes a reduction furnace body, a dispersion plate, and a dispersion plate foreign material removing unit. The reduction furnace body forms a fluidized bed of iron ore therein and is connected with the gas conduit to receive the reducing gas from the gas conduit. The dispersion plate is installed under the fluidized bed in the reduction furnace body, and is provided with a plurality of nozzles to distribute and supply the reducing gas to the fluidized bed. Dispersion plate foreign matter removal unit is located outside the main body of the reduction furnace, and includes a charging bin for storing the foreign spectroscopy for removing the foreign matter, and a control valve installed between the outlet of the charging bin and the gas conduit to control the discharge of the fine spectroscopy for removing the foreign matter; When the nozzle is clogged, inject the fine spectroscopy for removing foreign substances into the reducing gas.

The flow reduction furnace may further include a differential pressure gauge installed in the reduction furnace body to detect a pressure difference between the top of the fluidized bed and the bottom of the fluidized bed. The dispersion plate foreign material removing unit may further include a control unit connected to the control valve and the differential pressure gauge to control the operation of the control valve using the pressure data measured by the differential pressure gauge.

Fine spectroscopy for removing foreign matter is iron ore, and may have a particle size in the range of 0.2mm to 1mm. The dispersion plate includes a horizontal portion in which a plurality of holes are formed, and the plurality of nozzles are formed to protrude toward the lower portion of the reduction furnace body from the horizontal portion while connecting to each hole, and a spiral groove portion may be formed on the inner circumferential surface of each of the plurality of nozzles. have.

The plurality of nozzles may be formed in a shape in which the inner diameter and the outer diameter gradually increase as the distance from the horizontal portion increases. The reducing gas introduced into the reduction furnace body may have a temperature in the range of 600 ° C to 850 ° C.

The fluid reduction furnace includes a preheating furnace, a preliminary reduction furnace, and a final reduction furnace, and the dispersion plate foreign material removing unit may be installed in the final reduction furnace.

One embodiment of the present invention is provided with a dispersion plate having a plurality of nozzles therein, to form a fluidized bed of iron ore over the dispersion plate, receiving a reducing gas from the gas conduit to distribute the reducing gas to the fluidized bed through the dispersion plate In the supply flow reducing furnace, detecting the nozzle clogging of the dispersion plate, and when the nozzle of the dispersion plate is clogged, by introducing a fine spectroscopy for removing foreign matters with reducing gas by applying impact energy to the nozzle surface with a fine spectroscopy for removing foreign matters The present invention provides a method for removing foreign matter on a dispersion plate of a flow reduction furnace including removing foreign matter attached to a nozzle surface.

Iron ore having a particle size in the range of 0.2 mm to 1 mm can be used as fine spectroscopy for removing foreign matter. A spiral groove may be formed on the plurality of nozzle inner circumferential surfaces to impart centrifugal force to the reducing gas passing through the nozzle.

According to this embodiment, it is possible to efficiently remove the foreign matter attached to the dispersion plate nozzle without interrupting the operation by opening the control valve periodically during the operation of the molten iron manufacturing equipment to discharge the fine spectroscopy for removing foreign matter. In addition, the fuel cost can be reduced by increasing the temperature of the reducing gas to increase the ore reduction rate.

1 is a schematic diagram of a molten iron manufacturing equipment having a flow reduction furnace according to an embodiment of the present invention.
FIG. 2 is an enlarged view of the flow reduction furnace shown in FIG. 1.
3 is a partially enlarged cross-sectional view of the dispersion plate shown in FIG. 2.
4 is a schematic view showing a path of a reducing gas passing through the dispersion plate nozzle shown in FIG. 3.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. The present invention may be embodied in many different forms and is not limited to the embodiments described herein.

1 is a schematic diagram of a molten iron manufacturing equipment having a flow reduction furnace according to an embodiment of the present invention.

Referring to FIG. 1, the FINEX crucible manufacturing facility includes a melting furnace 10 and a multi-stage fluidized-bed reactors 21, 22, and 23. The flow reduction furnaces 21, 22, and 23 may be configured as three stages of the preheating furnace 21, the preliminary reduction furnace 22, and the final reduction furnace 23. The final reduction furnace 23 is connected to the melting furnace 10, and a coal-filled layer is formed inside the melting furnace 10.

The iron ore moves along the first to fourth ore conduits 31, 32, 33, and 34 in order of the preheating furnace 21, the preliminary reduction furnace 22, the final reduction furnace 23, and the melting furnace 10. do. The reducing gas of the melting furnace 10 is passed through the hot cyclone 45 to the final reducing furnace 23, the preliminary reducing furnace 22, and the first to fourth gas conduits 41, 42, 43, and 44. The preheating furnace 21 is discharged to the outside of the manufacturing facility.

The iron ore is charged into the preheating furnace 21 through the first ore conduit 31, and the fluidized bed in the upper part of the distribution plate 50 in the preheating furnace 21 by the reducing gas supplied from the third gas conduit 43. Preheated while forming. The iron ore is then charged into the preliminary reduction furnace 22 through the second ore conduit 32, and the upper part of the dispersion plate 50 in the preliminary reduction furnace 22 by the reducing gas supplied from the second gas conduit 42. Pre-reduced while forming a fluidized bed at.

The pre-reduced ferrous iron ore is charged into the final reduction furnace 23 through the third ore conduit 33 and the dispersion plate 50 in the final reduction furnace 23 by the reducing gas supplied from the first gas conduit 41. ) Is finally reduced while forming a fluidized bed at the top. The reduced ore is charged to the melting furnace 10 through the fourth ore conduit 34, and is melted in the coal packed bed to be converted into molten iron. The reducing gas in the preheating furnace 21 is discharged to the outside of the facility via the fourth gas conduit 44.

Outside the flow reduction furnaces 21, 22, 23, in particular, the final reduction furnace 23, a dispersion plate foreign matter removing unit 60 for introducing foreign matter removal fine spectroscopy into a nozzle of the dispersion plate 50 is installed if necessary. . In addition, the dispersion plate 50 installed in the final reduction furnace 23 has an improved nozzle structure to facilitate foreign material removal.

FIG. 2 is an enlarged view of the final reduction furnace shown in FIG. 1, FIG. 3 is a partially enlarged cross-sectional view of the dispersion plate shown in FIG. 2, and FIG. 4 is a path of reducing gas passing through the dispersion plate nozzle shown in FIG. 3. It is a schematic diagram showing.

2 to 4, the final reduction furnace 23 includes a reduction furnace body 25, a dispersion plate 50 and a support body 26 located inside the reduction furnace body 25, and a reduction furnace body ( 25) a dispersion plate foreign material removal unit 60 located outside.

The dispersion plate 50 is installed on a support 26 made of refractory bricks, and the fluidized bed 27 of iron ore is disposed on the dispersion plate 50. Hundreds of gas passage nozzles 51 are formed in the dispersion plate 50 at regular intervals to uniformly disperse the reducing gas flowing through the first gas conduit 41 into the fluidized bed 27. A cylindrical space portion 261 corresponding to each nozzle 51 of the dispersion plate 50 is formed in the support 26 to open the nozzle 51.

The dispersion plate 50 has a flat horizontal portion 52 that forms a plurality of holes 521, and protrudes from the horizontal portion 52 toward the lower portion of the reduction furnace body 25 while connecting to each hole 521. It includes a plurality of nozzles (51). The nozzle 51 is formed in a shape in which the inner diameter and the outer diameter gradually increase as the distance from the horizontal portion 52 increases. That is, the nozzle 51 may be formed to gradually narrow the inner diameter and the outer diameter toward the horizontal portion 52 from the lower end contacting the reducing gas first.

A threaded spiral groove 53 is formed on the inner circumferential surface of the nozzle 51 of the dispersion plate 50. The spiral groove portion 53 generates centrifugal force by rotating the reducing gas passing through the nozzle 51. Accordingly, the reducing gas introduced from the first gas conduit 41 into the reduction furnace body 25 passes through the nozzle 51 and the horizontal portion 52 while forming a rotational flow by the spiral groove portion 53 inside the nozzle 51. do.

The reducing gas flowing into the reduction body 25 includes dusts such as pyrolysis residues of coal and fine reduced iron and alkali chlorides. The dust contained in the reducing gas is attached to the inner wall of the nozzle 51 as foreign matter while passing through the nozzle 51 of the dispersion plate 50. In particular, alkali chlorides such as potassium chloride (KCl) or sodium chloride (NaCl) may be attached to the surface of the nozzle 51 as foreign matter because it is present in the liquid phase at a high temperature to have an adhesive force.

The dispersion plate foreign material removing unit 60 discharges the foreign matter removal fine spectroscopy 61 to the first gas conduit 41 to remove the foreign matter fine spectra 61 for removing the foreign matters from the reducing gas flowing into the dispersion plate 50. Inflow.

The dispersion plate foreign material removal unit 60 receives a charge bin 62 that receives and stores the foreign spectroscopy 61 for removing the foreign matter, and a branch pipe 63 that connects the charge bin 62 and the first gas conduit 41 to each other. And a control valve 64 provided between the outlet of the charging bin 62 and the branch pipe 63 to control the discharge of the fine spectrometer 61 for removing foreign matter. The control valve 64 also serves to prevent backflow of reducing gas towards the charging bin 62.

The reduction main body 25 is provided with a differential pressure gauge 28 for detecting a pressure difference between the upper part of the fluidized bed 27 and the lower part of the fluidized bed 27. The degree of blockage of the dispersion plate 50 may be calculated using the pressure data measured from the differential pressure gauge 28. The dispersion plate foreign material removing unit 60 includes a control valve 64 and a control unit (not shown) connected to the differential pressure gauge 28.

The control unit recognizes that the nozzle 51 of the distribution plate 50 is partially blocked when the pressure detected by the differential pressure gauge 28 is greater than or equal to a predetermined value during the operation of the molten iron manufacturing equipment, and opens the control valve 64 to charge the charging bin 62. Discharge the spectroscopic 61 for removing the foreign matter stored in). At this time, it is possible to control the discharge of the fine spectroscopy 61 for removing the foreign matter according to the opening degree of the control valve (64).

The discharged fine spectroscopy 61 is introduced into the reduction body 25 together with the reducing gas by being introduced into the first gas conduit 41 through the branch pipe 63. Reducing gas including the foreign matter removal fine spectroscopy 61 is rotated by centrifugal force inside the nozzle 51 while passing through the nozzle of the dispersion plate 50, during this process, fine dust for removing foreign matters having a greater density than the reducing gas. While 61 is pushed outward, it rotates in close contact with the inner peripheral surface of the nozzle 51 (see FIG. 4). The spiral groove portion 53 formed in the nozzle 51 as described above functions to double the impact amount of the fine spectrometer 61 for removing foreign matter.

Therefore, foreign matter adhering to the surface of the nozzle 51 is continuously separated from the nozzle 51 by collision energy while continuously colliding with the fine spectroscopy 61 for removing the foreign matter. The foreign matter separated from the nozzle is introduced into the fluidized bed 27 together with the reducing gas and the fine spectroscopy 61 for removing the foreign matter. Through this process, foreign matter attached to the inner circumferential surface of the nozzle 51 can be effectively removed.

The foreign spectroscopy 61 for removing the foreign matter is preferably iron ore, which is the same component as the fluidized bed 27, and may have a particle size of about 0.2 mm to 1 mm. If the particle size of the foreign matter removal fine spectrometer 61 is less than 0.2 mm, it is difficult to discharge smoothly from the charging bin 62, and it is difficult to apply sufficient collision energy to the foreign matter attached to the inner peripheral surface of the nozzle 51 when rotating by centrifugal force. Foreign material removal efficiency may be lowered. If the particle size is larger than 1 mm, the branch pipe 63 or the gas conduits 41, 42, 43 may be blocked by the foreign spectroscopy 61 for removing the foreign matter.

When the foreign matter adhering to the inner circumferential surface of the nozzle 51 is removed by the action of the foreign matter removal fine spectrometer 61, the detected pressure of the differential pressure gauge 28 is lowered below the set value. Then, the control unit closes the control valve 64 to stop the discharge of the fine spectroscopy 61 for removing the foreign matter.

As described above, the final reduction furnace 23 of the present embodiment senses the detection pressure of the differential pressure gauge 28 in real time and periodically discharges the fine spectroscopy 61 for removing foreign substances by opening the control valve 64 periodically during the operation of the molten iron manufacturing equipment. do. Therefore, the foreign matter adhering to the nozzle 51 of the dispersion plate 50 can be efficiently removed without interrupting the operation.

On the other hand, the melting point of alkali chlorides, such as potassium chloride or sodium chloride, included in the reducing gas is approximately 750 ° C. If the temperature of the reducing gas is higher than the melting point of the alkali chloride, the alkali chloride is attached to the nozzle 51 of the dispersion plate 50 in the form of a liquid phase. Thus, conventionally, cooling gas is injected into the reducing gas discharged from the melting furnace to reduce the temperature of the reducing gas. Was lowered below the melting point of the alkali chloride.

However, since the final reduction furnace 23 of the present embodiment includes a dispersion plate foreign matter removing unit 60 which periodically removes foreign matters of the distribution plate nozzle 51, the temperature of the reducing gas introduced into the reduction body main body 25. Can be kept above the melting point of the alkali chloride.

The reducing gas introduced into the reduction body 25 may have a temperature of approximately 600 ° C. to 850 ° C. When the temperature of the reducing gas is less than 600 ° C., the ore reduction rate is lowered. When the temperature of the reducing gas is higher than 850 ° C., the amount of foreign matter adhering to the dispersion plate nozzle 51 increases, so that the efficiency of the dispersion plate foreign material removing unit 60 may be reduced. .

As the temperature of the reducing gas is higher, the ore reduction rate can be increased, and thus, the flow reduction furnaces 21, 22, and 23 of the present embodiment, in particular, the final reduction furnace 23, prevent clogging of the nozzle 51 of the dispersion plate 50. In addition to increasing the ore reduction rate can be implemented to reduce the fuel cost.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, Of course.

10: melting furnace 21, 22, 23: flow reducing furnace
25: reduction furnace body 26: support
27: Fluidized bed 28: Differential pressure gauge
31, 32, 33, 34: Ore conduits 41, 42, 43, 44: Gas conduits
45: hot cyclone 50: dispersion plate
51: nozzle 52: horizontal portion
53: spiral groove portion 60: dispersion plate foreign material removal portion
61: Unspectral spectroscopy 62: Charging bin
63: branch pipe 64: control valve

Claims (11)

A reduction furnace body forming a fluidized bed of iron ore therein and connected with a gas conduit to receive a reducing gas from the gas conduit;
A distribution plate installed below the fluidized bed in the reduction furnace body and having a plurality of nozzles to distribute and supply the reducing gas to the fluidized bed; And
A charging bin located outside the main body of the reduction furnace and storing the foreign spectroscopy for removing foreign matters, and a control valve installed between the outlet of the charging bin and the gas conduit to control discharge of the foreign spectroscopy for removing foreign substances, Dispersion plate foreign material removal unit for injecting the fine spectroscopy for removing the foreign matter with a reducing gas when the nozzle clogging
Flow reduction furnace comprising a. The method of claim 1,
And a differential pressure gauge installed at the reduction furnace body to detect a pressure difference between the upper portion of the fluidized bed and the lower portion of the fluidized bed. The method of claim 2,
The dispersion plate foreign matter removing unit further comprises a control unit connected to the control valve and the differential pressure gauge to control the operation of the control valve using the pressure data measured by the differential pressure gauge. The method of claim 1,
The foreign spectroscopy for removing foreign matter is iron ore, the flow reduction furnace having a particle size in the range of 0.2mm to 1mm. 5. The method according to any one of claims 1 to 4,
The dispersion plate includes a horizontal portion in which a plurality of holes are formed, and the plurality of nozzles are formed to protrude toward the lower portion of the reduction furnace main body from the horizontal portion while being connected to each hole, and a spiral is formed on an inner circumferential surface of each of the plurality of nozzles. Flow reduction furnace in which grooves are formed. The method of claim 5,
The plurality of nozzles are formed in a flow reduction furnace formed in a shape that gradually increases the inner diameter and the outer diameter as the distance from the horizontal portion. The method of claim 1,
Reduction gas introduced into the reduction furnace body is a flow reduction furnace having a temperature in the range of 600 ℃ to 850 ℃. The method of claim 1,
The flow reduction furnace includes a preheating furnace, a preliminary reduction furnace, and a final reduction furnace,
The dispersion plate foreign matter removal unit is a flow reduction furnace installed in the final reduction furnace. It is provided with a dispersion plate having a plurality of nozzles therein, to form a fluidized bed of iron ore over the dispersion plate, receiving a reducing gas from the gas conduit through the dispersion plate to supply the reducing gas to the fluidized bed through the flow reduction In the furnace,
Detecting nozzle blockage of the dispersion plate; And
Removing foreign matter attached to the nozzle surface by applying impact energy to the nozzle surface with the foreign matter removal fine spectroscopy by inserting fine spectroscopy for removing foreign substances into the reducing gas when the nozzle of the dispersion plate is clogged.
Dispersion plate foreign matter removal method of the flow reduction furnace comprising a. 10. The method of claim 9,
Dispersion plate foreign matter removal method of a flow reduction furnace using iron ore having a particle size in the range of 0.2mm to 1mm as the fine spectroscopy for removing foreign matter. 10. The method of claim 9,
Dispersing plate foreign matter removal method of the flow reduction furnace to form a spiral groove portion in the plurality of nozzle inner peripheral surface to impart a centrifugal force to the reducing gas passing through the nozzle.

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