KR101036634B1 - Apparatus for recycling dust in COREX process - Google Patents

Abstract

An object of the present invention is to reduce the increase in the flow rate of gas due to the occurrence of pressure peak during operation to prevent the coal or coke lumps to be introduced into the dust recovery device to reduce the clogging phenomenon of the Correx facility dust collection In providing a device.

Accordingly, the present invention provides a dust recovery apparatus of the Korex facility including a reduction unit installed on the generator gas line of the dust recovery device connecting the melting furnace and the hot cyclone to reduce the flow rate of the gas flowing into the generator gas line.

Generator Gas Line, Expansion Pipe, Grid, Gas Hole

Description

Apparatus for recycling dust in COREX process

1 is a schematic diagram showing a typical Korex installation,

Figure 2 is a side view showing a dust recovery apparatus of the Corex facility according to an embodiment of the present invention,

3 is a cross-sectional view showing a part of the dust recovery apparatus of the Corex facility according to an embodiment of the present invention,

Figure 4 is a side view showing a dust recovery apparatus of the Corex facility according to the prior art.

Explanation of symbols on the main parts of the drawings

50: expansion tube 51: steel bar

52: heat-resistant roll and 53: side manhole

54: upper manhole 60: grid

61: gas hole

150: hot cyclone 151: generator gas line

The present invention relates to a Korex facility, and more particularly to a dust recovery apparatus of the Korex facility.

In general, the blast furnace method, which constitutes a large scale of molten iron production equipment, requires a raw material having a certain level of strength and a particle size that can ensure the ventilation of the furnace.

Therefore, the carbon source used as fuel and reducing agent depends on coke processed with most of the raw coal, and the iron source mainly depends on the sintered ore through a series of bulking processes.

Therefore, the current blast furnace method using the coke and sintered ore as described above necessitates a raw material preliminary treatment equipment such as coke manufacturing equipment and sintering equipment, and therefore requires a huge cost for the production of the equipment, the repair and maintenance work In addition to this, since the raw material preliminary treatment facilities generate considerable environmental pollutants such as SOx, NOxe or dust, a separate facility for the purification treatment is required, and in particular, the global environmental pollution regulations As the production of molten iron through the blast furnace process is weakening due to the enormous investment in processing equipment to overcome this problem, its competitiveness is weakening.

In order to cope with the above situation, countries around the world directly use ordinary coal as fuel and reducing agent, and use iron ore as a source of iron ore as a source of iron pollutants with relatively low emission of environmental pollutants during the manufacturing process. The company is spurring the development of new steelmaking methods for manufacturing molten iron. As a representative example of the new steelmaking method, there is a Korex process.

As shown in Figure 1, the Corex facility is charged with the main raw material such as iron ore, pellets and secondary raw materials such as limestone, dolomite from the upper portion, and the recharging furnace (110) charged with coal. A melting furnace 120 for burning it by oxygen and a direct reduction iron reduced by the reducing gas generated in the melting furnace 120 are connected to the upper part of the melting furnace 120. It is composed of a reduced light supply unit 130 and the like supplied through the supply pipe (DRI Down Pipe) 131, the reduced light transfer channel, melts the reduced light by the reaction heat in the melting furnace 120 to directly manufacture molten iron, It is discharged to the outside along with slag.

Here, the carbon monoxide and hydrogen generated during the combustion process by the oxygen blown through the tuyere 121 installed in the melting furnace 120, the main gas is reduced into the reducing furnace 110 to pass through the charges. Produces a direct reduced light, the direct reduced light forms a fixed bed (Fixed Bed) with the ordinary coal supplied into the melting furnace (120).

Herein, the fixed layer 123 will be described. The coal in the melting furnace 120 is discharged and decomposed by the furnace temperature of about 1000 ° C. and filled into the middle of the melting furnace in the form of CHAR. Refers to an area consisting of.

In this way, the coal charged in the smelter 120 is released from the upper portion of the fixed bed volatiles, becomes a char consisting of a fixed carbon and ash (char), and reacts with the oxygen charged in the tuyere tip to generate carbon monoxide The molten iron is produced by melting the direct reduced ore existing in the fixed bed by the reaction heat. In addition, the reducing gas generated in the melting furnace 120 is cooled while passing through wet scrubbing scrubbers 141 and 142 installed in the reducing gas line 122 and the cooling gas line, and the fuel is a clean gas in which dust is removed. The gas is removed from the scrubbers (141, 142) is discharged to the outside through the stack (160).

In addition, the hot gas discharged from the melting furnace 120 to the outside contains a large amount of fine dust generated during the differentiation and reaction of the charge, the dome portion 124 of the upper portion of the melting furnace 120 to remove and reuse it By installing a dust recovery device including a dry dust removal hot cyclone (150) for each gas supply line connected to a plurality of), the dust is removed to prevent the gas containing a large amount of dust is not supplied into the reduction furnace 110 as it is, The dust is supplied to the dust burner 151 installed on the outer wall of the melting furnace 120 and combusted together with oxygen in the melting furnace 120.

Conventional dust recovery apparatus for this purpose is a generator gas line 151 installed in the dome portion 124 of the melting furnace 120 and the hot cyclone 150, hot cyclone installed on the line as shown in FIG. The dust discharged from the dust blocking valve 152, the upper disk gate 153, the upper dust bin 154, the lower disk gate 155, the lower dust bin 156, and the lower dust bin that are continuously disposed Blowing pipe 158 and the T-piece (T-Piece) 157 to be supplied to the burner 159 is included.

However, in the conventional structure, when a large amount of fine coal is charged into the upper part of the melting furnace, a large amount of gas is generated by a rapid combustion reaction in the melting furnace dome in a short time, causing a pressure peak, and a large amount of gas is used to protect the equipment. As it is discharged, the generator gas flow rate to the four generator gas lines is twice as fast as usual, and thus, the coal lumps and coke lumps of the small particles are introduced into the dust recovery device along with the gas, so that hot cyclones, upper dust bins, lower dust bins, A clogging phenomenon occurs in the dust blowing pipe, the tee-piece and the dust burner.

In the related art, in order to prevent dust from being mixed into a reduction furnace when a dust collecting device is blocked, a hot cyclone, an upper dust bin, a lower dust bin, a dust blowing pipe, a tee piece, and a dust burner are formed to stop the equipment and prevent the dust from being mixed into the reduction furnace. All the backs were dismantled to remove hot dust, coal and coke lumps.

However, the above-described conventional structure has a problem that it takes about 68-89 hours to stop the equipment for the cleaning operation and emptying the reduction furnace, so that there is a lot of downtime, which is a factor that lowers the productivity.

In addition, the emptying operation of the reduction furnace causes an increase in maintenance costs and alternative ore costs, lowering the operation rate due to the lack of molten iron production, there is a problem that the risk of safety accidents are very high and pollute the surrounding environment.

Accordingly, the present invention has been made to solve the above problems, and when the flow rate of the gas increases due to the occurrence of pressure peaks during operation, it is reduced by preventing the inflow of coal or coke lumps into the dust recovery device clogging the recovery device It is an object of the present invention to provide a dust recovery apparatus of a Korex facility that can minimize the phenomenon.

In order to achieve the above object, the present invention has a structure in which a reduction unit for reducing a gas flow rate is provided on a generator gas line connecting a melting furnace and a hot cyclone in a dust recovery apparatus.

The reduction unit is preferably a structure for reducing the flow rate of the gas by expanding the inner diameter of the line.

In addition, the present invention further includes a removal unit installed on the generator gas line to filter out coal lumps or coke lumps discharged along the lines.

Accordingly, it is possible to minimize the clogging of the recovery device by preventing the inflow of coal lumps or coke lumps in advance.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic view showing a typical Korex facility, Figure 2 is a side view showing a dust recovery apparatus of the Corex facility according to an embodiment of the present invention, Figure 3 is a dust of the Korex facility according to an embodiment of the present invention It is sectional drawing which shows a some structure of a collection | recovery apparatus.

According to the drawings, the Corex facility is a reduction gas in which the main raw material such as iron ore or pellets and the subsidiary materials such as limestone and dolomite are charged and blown together from the top and reduced in a solid state to directly reduce iron (DRI). ) To produce molten iron by burning with reduced oxygen (100) and direct reduced iron and charged coal transported from the reduction furnace (100) by the oxygen blown into the lower vent (121). Transfer screw for charging the reducing gas to be introduced into the melting furnace 120, the direct reduction iron produced from the reducing furnace 100 to the melting furnace 120 through the feed pipe 131 for the reduction (100) ( 121), a dust recovery device for recovering dust generated in the molten iron manufacturing process.

The dust recovery device includes a generator gas line 151 installed in the dome of the melting furnace 120 to transfer gas, and a hot cyclone 22 installed on the line to separate dust from hot gas. ), Which is continuously installed at the lower end of the hot cyclone 150, a dust cutoff valve 152 for blocking the discharge of dust, and an upper disk gate 153 for adjusting the transport amount of dust, and continuously below the upper disk gate. Blowing pipe 158 for supplying dust discharged from the upper dust bin 154, the lower disk gate 155, the lower dust bin 156, the lower dust bin to the dust burner 159 of the melting furnace 120 and Ti-piece 157 for nitrogen gas injection.

According to the present invention, in the dust recovery apparatus having the above-described structure, the expansion pipe for reducing the flow rate of the hot gas transported along the generator gas line 151 between the generator gas line 151 and the hot cyclone 150 ( 50 and a grid 60 installed inside the expansion pipe 50 so as to filter out coal lumps or coke lumps discharged to the expansion pipe 50 along the generator gas line 151.

Accordingly, when the pressure peak occurs in the melting furnace 120, the hot gas rapidly introduced into the generator gas line 151 flows into the expansion pipe 50 having a larger inner diameter than the gas line, and the flow velocity thereof decreases, thereby causing agglomerated dust. It is possible to weaken the emission of.

In addition, the grid 60 installed inside the expansion pipe 50 filters the lump or coke lump to prevent clogging of each component of the dust collecting device according to the dust discharge in the form of lumps.

The expansion pipe 50 is preferably installed perpendicularly to the vertical rising portion of the generator gas line 151, and the size thereof is not particularly limited, but four generator gas lines (or pressure peaks) are normally generated. Considering that the generator gas flow rate flowing to the 151 is about twice as fast as usual, it is preferable to expand twice the inner diameter of the generator gas line 151.

In addition, looking at the configuration of the expansion tube 50, the outer shell 51 forming a cylindrical shape, and the heat-resistant lead 52 to be built in the outer shell to protect the outer shell from the hot gas, Side manhole 53 for side inspection is installed on the side, and upper manhole 54 for upper inspection is installed on the upper side, and flange 55 for connection with the generator gas line 151 is provided at the bottom and side, respectively. It is installed and bolted to the flange on the generator gas line 151.

On the other hand, the grid 60 is made of a heat-resistant twist to withstand high temperatures, is installed horizontally in the expansion pipe 50 and a plurality of gas holes 61 are arranged in a predetermined interval on the surface is formed through. And the outer circumferential surface has a shaft 62 is installed so that the grid 60 can be fixed to the expansion pipe 50 is configured to fix the bolt / nut from the expansion pipe 50 outside.

In this case, the total cross-sectional area of the gas hole 61 formed in the grid 60 is preferably configured to be the same as the cross-sectional area of the generator gas line 151.

Hereinafter, the operation of the present invention will be described.

In order to reduce the main and subsidiary materials charged into the reduction furnace 100, the reduction reaction is performed with the high temperature reducing gas generated in the melting furnace 120, and the manufactured direct reducing iron is transferred to the lower end of the reduction furnace 100. It is charged constantly into the melting furnace 120 into 121.

At this time, when a large amount of pulverized coal is charged into the melting furnace 120, a rapid combustion reaction occurs in a short time in the dome of the melting furnace 120 (the reaction of the coal is completed within about 1-2 seconds), and thus a large amount of gas is generated. This results in a pressure peak due to increased generator gas flow rate.

Therefore, the generator gas flow rate flowing to the four generator gas lines 151 is twice as fast as usual by discharging a large amount of gas in order to lower the equipment from the pressure peak as described above. The gas flows into the generator gas line 151 together with the gas due to the rapidly high flow rate.

As such, the gas introduced into the generator gas line 151 and the coal and coke lumps of the small particles flow into the expansion pipe 50 installed on the generator gas line 151, and thus the flow rate is rapidly decreased and thus accompanied by the flow rate of the gas. Small grains of coke and coke lumps fall to the bottom.                     

In addition, the coal and coke lumps of small particles which are not dropped through the flow rate drop and are discharged together with the gas do not pass through the gas hole 61 formed in the grid 60 while passing through the grid 60 installed in the expansion pipe 50. Not separated from the gas.

Therefore, a large amount of gas flows into the generator gas line 151 due to the pressure peak generated during the operation, thereby preventing the coal and coke lumps of the small particles from being introduced into the dust recovery apparatus by increasing the flow rate.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it belongs to the scope of the invention.

As described above, according to the dust recovery apparatus of the Corex facility according to the present invention, during the process of manufacturing molten iron, when the pressure peak occurs due to rapid pulverized coal combustion, the flow rate of the gas flowing into the generator gas line is reduced, and the coal and coke of the small particles through the grid are reduced. By filtering the lumps, it is possible to fundamentally prevent clogging of the dust recovery facility due to the inflow of coal and coke lumps.

In addition, the dust recovery device, as well as prevent the fluctuations in the operation index of the reduction furnace, improve the operation rate, reduce the cost of manufacturing molten iron, and can reduce the maintenance cost by preventing plant downtime, and large equipment accidents There is an effect that can be prevented in advance.

Claims (7)

It is provided on the generator gas line of the dust recovery device connecting the melting furnace and the hot cyclone and includes a reduction unit for reducing the flow rate of the gas flowing into the generator gas line, The reduction portion is an expansion pipe having a larger inner diameter than the generator gas line, The expansion pipe is formed of an outer steel shell forming a cylindrical shape, a heat-resistant lead to protect the outer steel shell from the hot gas being constructed in the outer steel shell, a side manhole installed on the side for side inspection, and installed at the top for the upper inspection. Dust recovery apparatus of Korex facility, characterized in that it comprises an upper manhole. delete 2. The dust collecting apparatus according to claim 1, wherein the expansion pipe has an inner diameter twice that of the generator gas line. delete [4] The dust recovery apparatus according to claim 1 or 3, further comprising a removal unit installed on the generator gas line to filter out coal pellets or coke lumps of small particles discharged with the gas. . The dust collecting apparatus of claim 1, wherein the removing unit is horizontally installed in the extension pipe, and a plurality of gas holes are arranged at predetermined intervals on the surface of the removal unit, and formed of a grid of heat-resistant rolled material and a material formed therethrough. 6. The dust collection apparatus of the Korex facility according to claim 5, wherein the total cross-sectional area of the gas hole formed in the grid is the same as that of the generator gas line.

Images