KR19980026164A - Exhaust Gas Circulation Iron Ore Sintering Equipment - Google Patents

Abstract

The present invention relates to an iron ore sintering apparatus for sintering iron ore by the exhaust gas circulation type iron ore sintering method, wherein the exhaust gas discharged from the front of the sintering machine is almost completely affected by oxygen concentration and water vapor by the end of coke combustion. The high temperature sintered combustion layer by pyrolysis of NOx contained in the exhaust gas while reducing the amount of exhaust gas in the existing sintering machine without significantly increasing the facilities in the existing sintering furnace, and the carbon monoxide resulting from coke incomplete combustion in the first half of the sintering machine It is an object of the present invention to provide an exhaust gas circulation type iron ore sintering apparatus capable of further reducing NOx by reducing the amount of fuel required for sintering and thus suppressing the generation of NOx due to combustion of fuel.

The present invention is a sinter bogie (7) for transferring the sintered raw material, a plurality of wind phase (9) located in the lower portion of the bogie 7 to suck the air required for the sintering reaction and the exhaust gas sucked through the wind phase after the sintering reaction dust collector (61) In the iron ore sintering apparatus comprising a main exhaust pipe (50) to be sent to), the main exhaust pipe (50) between the dust collector 61 and the foremost wind phase (9) to the first blocking port (51) Blocked by; A hood 70 formed around the sintered bogie 7 from the rear end of the sintering machine to a reference position at which the exhaust gas temperature rises rapidly is installed; The main exhaust pipe portion corresponding to the reference position is blocked by the second blocking port 52; The main exhaust pipe 50 between the first blocking port 51 and the second blocking port 52 is a main exhaust pipe between the second blocking port 52 and the rear end of the main exhaust pipe through the exhaust gas recirculation device 80. And gas communication; The present invention also relates to an exhaust gas circulation type iron ore sintering apparatus configured to be in gas communication through a gas discharge pipe in the dust collector 61 and the hood 70.

Description

Exhaust Gas Circulation Iron Ore Sintering Equipment

Figure 1: Schematic diagram showing a conventional iron ore sintering process

2 is a schematic diagram showing the change of O ₂ , NO _x and H ₂ O content, exhaust gas temperature and flow rate according to the sinter strand in the conventional iron ore sintering process

3 is a block diagram showing an example of the exhaust gas circulation type iron ore sintering apparatus of the present invention

4 is a configuration diagram showing another example of the exhaust gas circulating iron ore sintering apparatus of the present invention

5 is a reaction state diagram showing the reaction state in the sintered layer when sintering iron ore according to the present invention

6 is a schematic diagram of a sintering experiment apparatus for explaining the effect of the present invention

* Description of the symbols for the main parts of the drawings *

50, 150 ... main exhaust pipe 51 ... first block

52 ... Secondary shutoff 151

70,170 Laryngeal 80,180 Flue gas recirculation unit

81,181 Exhaust gas extraction pipe 82,182

83,183 Circulation fan 84,184

90,190 Gas exhaust pipe 91,191 Boiler

The present invention relates to an iron ore sintering apparatus for sintering iron ore by the exhaust gas circulation iron ore sintering method, and more particularly to an exhaust gas circulating iron ore sintering apparatus capable of reducing nitrogen oxides (hereinafter referred to as NO _x ). As related, it is an improvement of Korean Patent Application No. 96-11405.

Generally, in the sintering plant, as shown in FIG. 1, sintering raw materials including various iron ores and secondary raw materials and powdered coke are mixed and charged into the sintering raw material hopper 2 of the iron ore sintering machine 1, and the raw materials are charged. Is loaded into the sintering machine trolley 7 via the inclined plate 5 by the rotation of the drum feeder 4 above the bottom light which is first laid on the sintering machine trolley 7 through the bottom light hopper 3. Then, the surface of the sintered raw material is ignited in the ignition furnace 6, and coke is burned in the sintered raw material layer 8 by air sucked downwardly from the wind phase 9 by the suction blower 12. To produce a sintered ore.

At this time, the air sucked through the wind (9) is collected in the electric dust collector 11 via the main exhaust pipe 10 is discharged to the chimney (13).

The produced sintered ore is first crushed in the high temperature crusher 14, put into the cooler 15, and cooled, and the cooled sintered ore is produced as a sintered ore of a predetermined size in the low temperature crusher 16 and the screen 17 to the furnace 18. Will be sent.

As described above, the gas discharged during the production of sintered ore contains a large amount of dust (dust) containing alkali chlorides, and SOx and NOx, which are substances to be regulated in the air environment mainly caused by the combustion of coke, and their emissions are usually 30 Since it is a large amount of about 1,200,000 Nm3 / hr, a significant investment cost is required for the installation of air pollution prevention facilities, and the operation cost is high, which greatly deteriorates the economics of the sintering facilities.

In recent years, various environmental regulations have become increasingly stringent.

Therefore, in recent years, effective exhaust gas is recycled and utilized in consideration of air pollution caused by exhaust gas and air pollution prevention equipment cost, and a method of reducing actual emission of exhaust gas, stacking sintered raw materials in two layers and sintering in two stages The two-stage ignition sintering method used in both raw material layers and the method of reducing the size of the pollution prevention facility by increasing the efficiency of the catalyst for decomposing various pollutants contained in the flue gas are being conducted.

The present invention relates to an exhaust gas circulation sintering method that can reduce the amount of exhaust gas by reducing the amount of exhaust gas by circulating and reusing exhaust gas, and the exhaust gas circulation sintering method will be described below.

The flue gas circulation sintering method was developed in the early 70's in terms of energy reduction, and is disclosed in Japanese Patent Application Laid-Open Nos. 52-153803, 53-8302, and 53-76103.

The exhaust gas circulation sintering method has been implemented in some steel mills since the early 80's, and recently, the concept has been expanded in the aspect of pollution prevention with a technology that can reduce the amount of exhaust gas.

As a practical example of application, first, a method of partially circulating the exhaust gas in accordance with its characteristics by fully utilizing the characteristics of the exhaust gas (1st Inter. Cogress of Science and Technology of Ironmaking, 1994, Sendai, ISIJ, p 659-664), Second, in order to greatly increase the exhaust gas circulation, a part of the entire exhaust gas is circulated through the sintering machine (Ironmaking conference Proceedings, vol. 51, toronto, canada, p 73-79), and third, in the on-strand cooling type sintering machine. The main method is to recover the sensible heat of the hot exhaust gas by circulating the sinter gas and the cooling gas throughout the sintering machine (IISC, 6th Inter Iron Steel Congress, Vol. 2, Nagoya, Japan, 1990), and fourth, the hot part of the exhaust gas. To recover the sensible heat of the exhaust gas by circulating the sinter in some sintering machine [CAMP-ISIJ Vol. 4 (1991) -119].

However, the first method has a problem in that a complicated exhaust gas reduction process or facility that can fully utilize the characteristics of the exhaust gas and in particular, reduce the amount of coke while maintaining productivity and quality, is complicated and has high investment costs.

The second method circulates some of the entire exhaust gas without utilizing the characteristics of the partial exhaust gas, so there is a risk of deterioration in productivity and quality due to lack of oxygen and excess water vapor, and additionally a large-scale facility is needed to cope with this problem. There is this.

In addition, the third method is a model suitable for a unique sintering machine of the On-Strand Cooling type, but there is a similar problem to the second method, and the fourth method is a process for the purpose of sensible heat recovery to circulate a part of the hot exhaust gas to the sintering machine. There is a problem in that the flue gas reduction effect is small.

That is, each of the sintering methods described above has a common problem that a large amount of equipment such as large pipelines and dust collectors are complicated and expensive, since the exhaust gas reduction process is adopted while maintaining a general sintering pattern. .

On the other hand, in order to reduce the pollutants, effective exhaust gas is circulated to the sintering machine, and the gas generated in the middle part of the sintering machine where the pollutants are concentrated is treated with a pollution treatment facility (Japanese Patent Application Laid-Open No. 55-47331). Method of branching and treating concentrated sintering gas in the middle part (Japanese Patent Laid-Open No. 55-58339), circulating effective flue gas to the sintering system, but rehumidifying to reduce the adverse effect and treating other flue gas generated in Japan Japanese Patent Application Laid-Open No. 53-32762). These methods are methods for reducing the facility investment cost of the pollution treatment device by branching the effective flue gas circulation or concentration. In addition, these methods are exhaust gas circulation type methods, and are also intended to reduce NOx by decomposing NOx by pyrolysis reaction by circulating NOx in exhaust gas in a high temperature combustion layer in a sintered bed. However, these methods produce NOx decomposition but have a small degree of decomposition.

Accordingly, the present inventors have conducted research and experiments to solve the above problems of the conventional methods, and based on the results, the present invention proposes that the exhaust gas discharged from a part of the sintering machine is used for the combustion of coke. By supplying to the high temperature sintering combustion layer in the second half of the sintering machine which is almost unaffected by the oxygen concentration and water vapor, the pyrolysis of NOx contained in the exhaust gas while reducing the amount of exhaust gas in the existing sintering machine without significant equipment addition, and the sintering machine Carbon monoxide (CO) caused by coke incomplete combustion in the first half is secondary burned in the high temperature sintered combustion layer, thereby reducing the amount of fuel required for sintering and thus reducing NOx by suppressing the generation of NOx due to combustion of fuel. To provide an exhaust gas circulating iron ore sintering apparatus, the purpose is .

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated.

The present invention is an iron ore comprising a sintered bogie for transferring the sintered raw material, a plurality of wind phases located in the lower portion of the bogie to suck air required for the sintering reaction, and a main exhaust pipe for sending exhaust gas sucked through the wind after the sintering reaction to the dust collector. A sintering apparatus, wherein the main exhaust pipe between the dust collector and the front wind is blocked by a first blocking port; A hood configured to surround the sintering bogie at an upper portion of the sintering bogie from a rear end of the sintering machine to a reference position where the exhaust gas temperature rises rapidly; A main vent pipe portion corresponding to the reference position is blocked by a second blocking hole; The main exhaust pipe between the first and second shutoff ports is connected to the main exhaust pipe between the second shutoff port and the rear end of the main exhaust pipe through a gas recirculation device in a gas communication relationship; In addition, the dust collector and the hood in the exhaust gas circulation type iron ore sintering apparatus configured to be in gas communication through the gas discharge pipe. In addition, the present invention comprises a sinter bogie for transferring the sintered raw material, a plurality of wind and the main exhaust pipe which is installed in the lower portion of the air phase in the air and gas and gas communication relationship located in the lower portion of the sintered bogie to suck the air required for the sintering reaction In the iron ore sintering apparatus, the line and the rear end of the main exhaust pipe is blocked; The main exhaust pipe portion corresponding to the reference position at which the exhaust gas temperature rises rapidly is blocked by the blocking port to form a first main exhaust pipe and a second main exhaust pipe; A hood configured to surround the sintering bogie at an upper portion of the sintering bogie from a rear end of the sintering machine to a reference position where the exhaust gas temperature rises rapidly; The first main exhaust pipe and the second main exhaust pipe are connected in gas communication through an exhaust gas recirculation device; The hood is connected in gas communication to the chimney through a gas discharge pipe; And it relates to an exhaust gas circulation type iron ore sintering apparatus is provided with a dust collector in the gas discharge pipe.

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

Iron ore sintering apparatus of the present invention, as can be seen in Figure 3 showing an embodiment of the present invention, is located in the sinter bogie 7, the sinter bogie 7 for transferring the sintering raw material 8, the sintering reaction An iron ore sintering apparatus including a plurality of traps (9) for sucking air required for air and a main blower tube (50) for sending exhaust gas sucked through the trap (9) after the sintering reaction to the dust collector (61) is improved. .

In the conventional iron ore sintering apparatus of the exhaust gas circulation type iron ore sintering apparatus of the present invention, the main exhaust pipe (50) between the dust collector (61) and the foremost wind phase (9a) is provided with a first blocking hole. A 51 is provided, and a hood 70 formed to surround the sintered bogie 7 is installed at the top of the sintered bogie 7 from a rear end of the sintering machine to a reference position where the exhaust gas temperature rises sharply. The main vent pipe 50 corresponding to the position is blocked by the second blocking port 52.

The main exhaust pipe 50 between the first blocking port 51 and the second blocking port 52 is connected between the second blocking port 52 and the rear end of the main exhaust pipe 50 through the exhaust gas recirculation device 80. It is connected to gas communication with main exhaust pipe. The exhaust gas recirculation apparatus 80 includes an exhaust gas extraction pipe 81 having one end connected to the main exhaust pipe 50 between the first blocking port 51 and the second blocking port 52, and the exhaust gas extraction pipe 81. The second dust collector 82 and the circulation fan 83 and one end is installed in the exhaust gas extraction pipe 81, the other end is connected to the main exhaust pipe 50 between the second blocking port 52 and the rear end of the main exhaust pipe It is preferably configured to include a circulating gas injection pipe (84).

On the other hand, the dust collector 61 and the hood 70 is configured to be in gas communication via the gas discharge pipe (90).

The gas discharge pipe 90 may be provided with a boiler 91 for recovering the sensible heat of the high-temperature exhaust gas, in which case it is possible to recover energy more economically.

On the other hand, the other exhaust gas circulation type sintering apparatus of the present invention, as can be seen in Figure 4 showing another embodiment of the present invention, the sintered bogie 7, the sintered bogie 7 for transferring the sintered raw material 8 In the iron ore sintering apparatus comprising a plurality of wind phase (9) located in the lower portion to suck the air required for the sintering reaction and the main air pipe 150 installed in the lower portion of the wind phase in a gas communication relationship with the wind phase, the main air blowing The line and the rear end of the pipe 150 are blocked, and the main air pipe part corresponding to the reference position at which the exhaust gas temperature rises sharply is blocked by the blocking port 151, so that the first main air pipe 150a and the second main A hood 170 is formed to surround the sintered trolley 7 at the upper end of the sintered trolley 7 from the rear end of the sintering machine to a reference position where the exhaust gas temperature rises rapidly. The first main exhaust pipe 150a and the second Exhausting pipe (150b) is connected to a gas communication between the exhaust gas recirculated through the device 180.

The exhaust gas exhaust circulation device includes an exhaust gas extraction pipe 181 having one end connected to a first main exhaust pipe 150a, a second dust collector 182 and a circulation fan 183 installed at the exhaust gas extraction pipe 181, and one end. The silver exhaust gas extraction pipe 181, the other end is preferably configured to include a circulating gas injection pipe 184 connected to the second main exhaust pipe (150b). In addition, the hood 170 is connected to the chimney 13 through a gas discharge pipe 190 in a gas communication relationship, the gas discharge pipe 190 is provided with a dust collector 161.

A boiler 191 may be installed in the gas discharge pipe 190 between the dust collector 161 and the suction blower 12, and in this case, energy may be recovered more economically.

Hereinafter, a method of sintering iron ore using the exhaust gas circulation type iron ore sintering apparatus of the present invention will be described.

In general, as shown in FIG. 2, in the sintering machine raw material layer, coke combustion starts after ignition (hereinafter referred to as FFP: Frame Front Plane) and combustion ends when cooling begins (hereinafter referred to as FBP: Frame As the coke burns, the ore melts and condenses between the behind planes. The coke combustion pattern and the pattern of generation of contaminants in the exhaust gas are closely related to each other. Firstly, the exhaust gas temperature rapidly rises to the point where the FFP reaches the bottom of the sinter (hereinafter referred to as P point), and the exhaust gas flow rate is increased in the first half of the sinter. There is a tendency to decrease to point P and then increase rapidly thereafter. In addition, the concentration of oxygen in the flue gas is lower during the combustion process depending on the degree of coke combustion and then increases after the point P where the amount of combustion is small. NOx and SOx in the flue gas also depend on coke combustion, so NOx is the opposite pattern of oxygen, and SOx is similar to flue gas temperature due to the influence of moisture in the sintered bed. In particular, after point P, coke combustion is almost finished, so the amount of oxygen required is small. This is particularly important for setting the recycle zone under conditions that do not deteriorate the sinterability because the gas discharged after the first combustion when exhaust gas is recycled to reduce the amount of exhaust gas contains a small amount of oxygen and contains a lot of water vapor. .

The operation of the sintering apparatus of the present invention will be described with reference to FIG. 2 showing the state of the gas discharged from the sintering machine and FIG. In FIG. 2, the state of the gas discharged from each part in the length direction of the sintering machine is shown. The flow rate in the layer starts at the point P where the raw material particles in the sintering layer are rapidly strengthened and maintained at a constant level while the sintering is almost completed. As a result, the airflow resistance in the layer decreases rapidly, and the trend is similar to the oxygen concentration and the gas temperature in the exhaust gas. The concentration of NOx, carbon monoxide (CO), and exhaust steam due to coke combustion tends to gradually increase as the initial generation gradually increases, and then decreases rapidly from the point P. Here, after point P, the flow resistance is low when the flow rate is increased, and when the trend of oxygen concentration is observed, the coke combustion is almost completed, indicating that the amount of oxygen required is small. From this, it can be said that the state of the recycle gas of the present invention is a state where the concentration of oxygen is low and the concentrations of water vapor, CO gas and NOx are high.

When the gas in such a state is injected from the lower part of the sinterer to the upper part of the sinterer through the main exhaust pipe 50 after the second breaker 52 installed after the point P using the exhaust gas recirculation device 80, First of all, due to low ventilation resistance, a large amount of gas can be injected.In particular, there is no condensation of water vapor due to the high temperature sintered layer, and the amount of oxygen required for combustion of coke is small. There is a characteristic that does not receive. Here, while the recycle gas passes through the high temperature sintering reaction layer (combustion layer), carbon monoxide contained in the gas is secondaryly burned in the high temperature reaction layer to supply reaction heat to the sintering reaction layer, and NOx contained in the recycle gas The thermal decomposition of the high temperature reaction layer and the carbon monoxide secondary combustion heat can be seen the effect of thermal decomposition to some nitrogen and oxygen. Here, the heat of combustion of the CO gas is transferred to the sintered layer, thereby reducing the amount of fuel required for sintering and thus reducing the generation of NOx itself due to the combustion of the fuel.

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

EXAMPLE

In order to test the effect of the sintering apparatus of the present invention, a sintering test apparatus as shown in FIG.

In FIG. 6, reference numeral 100 denotes a sintering test apparatus, 101 denotes a gas analyzer, 101a-b denotes a gas extractor, 102 denotes a chimney, 103 denotes a blower, 104 denotes a cyclone, 105 denotes a gas discharge pipe, 106 denotes a wind turbine, and 107 denotes a gas analyzer. Ports 108 are hoods, 109 are piping, TC-1 and TC-2 are thermocouples, and 110a-d are gas injectors.

The sintering test apparatus is configured by separately installing a gas (nitrogen, water vapor, carbon monoxide, NO ₂ ) injector to artificially change the composition of the air during the experiment in the sintering tester.

The raw materials used in this experiment were formulated with conventional sintered raw materials as shown in Tables 1 and 2 below, and the fuel was made of coke 3.5%, and the same was maintained in each experiment.

15% water vapor, 15% oxygen, 1 carbon monoxide starting from the time of injecting external air for the first time during the experiment, when the temperature of exhaust gas in the wind box at the bottom of the sintering port (measured by TC-2) reaches 120 ℃. %, NO ₂ 200ppm, was adjusted by a gas injector to the composition consisting of the remaining nitrogen was injected into the sintering tester. On the other hand, in the case of the conventional sintering method of Table 3 is to continue to inject air.

The composition of the inlet air and the exhaust gas is measured by the gas analyzer, and the temperature change in the bed is measured by the thermocouple (TC-1) installed at 20% of the height from the bottom of the sintered raw material layer. Shown in

In addition, the exhaust gas maximum temperature, sintering time, room temperature strength, and NOx reduction rate were measured, and the results are shown in Table 3 below.

TABLE 1

Raw material composition ratio (compound raw material) (Unit: Wt%)

TABLE 2

Chemical Composition of Blended Raw Materials (Unit: Wt%)

TABLE 3

As shown in Table 3, in the conventional sintering method, the maximum exhaust gas temperature is 237 ° C, the sintering time is 22 minutes 32 seconds, and room temperature intensity is 62.6.In the sintering method using the present invention, the maximum exhaust gas temperature is higher than that of the conventional sintering method. It can be seen that the temperature of about 10 ° C. and the temperature of TC-1 are increased by 20 ° C., the sintering time and room temperature intensity of the sintering property are almost similar to those of the conventional sintering method, and the NOx decomposition rate is about 12%.

Here, the temperature rise of the exhaust gas and TC-1 is a result of combustion of the injected carbon monoxide while passing through the high temperature sintering reaction layer, and the reduction of NOx is considered to be a result of partial pyrolysis in the high temperature sintering layer. In particular, if the amount of sintering fuel is reduced by the carbon monoxide combustion heat, various air pollutants such as NOx and SOx due to the combustion of fuel such as coke can be relatively reduced.

As described above, the sintering apparatus of the present invention does not significantly change the sinterability of sintered ore productivity, recovery rate, quality, etc., and the following effects are expected when the exhaust gas is circulated and sintered by the method of the present invention.

In the present invention, by recycling the circulating gas discharged after the first combustion in the latter part of the sintering machine where the sintering reaction is hardly influenced by the composition of the gas, there is no big problem in the sinterability such as productivity and quality. Upon completion, the resistance to airflow is low, allowing a large amount of gas to be supplied. Therefore, when the exhaust gas is recycled in this way, the circulation rate of the gas can be greatly increased, so the effect of reducing the exhaust gas is very large. In addition, about 1% of CO gas generated by the coke incomplete combustion of the first half of the sintering machine can be secondary burned in the circulating raw material layer, so that the amount of fuel such as coke required for sintering can be reduced by using this heat amount. There is an effect that can significantly reduce the NOx contained by thermal decomposition using the high temperature combustion layer passed through with the use of the secondary combustion heat of the CO gas. In this process, the NOx passes through the high temperature sintered bed and is thermally decomposed by the secondary combustion heat of the CO gas, and thus the energy required for the sintering process can be reduced by the secondary combustion heat of the CO gas, thus generating NOx due to the combustion of the coke. By reducing itself, the amount of NOx in the flue-gas can be significantly reduced throughout the entire process.

Furthermore, by replacing the large-scale gas circulation piping with the sintering raw material layer of the sintering machine in the existing method, the facility is extremely simple and the emitted dust is provided to the sintering raw material layer itself, thereby preventing the dust and additional effects of recycling waste resources. have.

The gas that is sucked by the existing blower and discharged is primarily filtered in the sintered raw material layer, which is mainly generated in the sintering machine, and the elements such as Cl, Na, Ka, etc., which form alkali chlorides, which greatly degrade the efficiency of the electrostatic precipitator, are recycled and passed again. As a result, the amount of alkali chloride is small, and the amount of processing gas is reduced as much as the exhaust gas is circulated compared to the capacity of the facility, thereby improving the efficiency of the electrostatic precipitator and drastically reducing the amount of dust emitted. In addition to the effect of recovering the high temperature sensible heat accumulated in the bottom of the sintering machine into the circulating gas, the phenomenon that the sintered ore is fused to the bottom of the sintering machine and stops the sintering machine can be fundamentally solved. It can be supplied to facilitate the cooling of the production sintered ore, and the economic effect is greater if the sensible heat of the high-temperature exhaust gas including the CO gas secondary combustion heat is recovered through the boiler.

Claims (6)

A plurality of wind beds (9) located at the lower part of the sinter bogie (7) for transferring the sintering raw material, the air for sucking the air required for the sintering reaction, and the exhaust gas sucked through the wind after the sintering reaction to the dust collector (61) In an iron ore sintering apparatus including a main main air pipe (50) to be sent, the main air exhaust pipe (50) between the dust collector (61) and the front wind phase (9) is blocked by the first blocking port (51). Become; A hood 70 formed around the sintered bogie 7 from the rear end of the sintering machine to a reference position at which the exhaust gas temperature rises rapidly is installed; The main exhaust pipe portion corresponding to the reference position is blocked by the second blocking port 52; The main exhaust pipe 50 between the first blocking port 51 and the second blocking port 52 is a main exhaust pipe between the second blocking port 52 and the rear end of the main exhaust pipe through the exhaust gas recirculation device 80. And gas communication; And the dust collector (61) and the hood (70) are in a gas communication relationship through a gas discharge pipe (90). The exhaust gas extraction pipe (81) according to claim 1, wherein the exhaust gas recirculation device is connected to a main exhaust pipe between one end of the first shutoff port (51) and the second shutoff hole (52). Circulating gas connected to the second dust collector 82 and the circulation fan 83, and one end of the exhaust gas extraction pipe 81, the other end of which is connected to the main exhaust pipe between the second blocking port 52 and the rear end of the main exhaust pipe. Exhaust gas circulation type iron ore sintering apparatus comprising an injection pipe (84). The exhaust gas circulation type iron ore sintering apparatus according to claim 1 or 2, wherein the gas discharge pipe (90) is provided with a boiler (91) for recovering sensible heat of the hot exhaust gas. The present invention is located in the lower portion of the sinter bogie (7), the lower portion of the sinter bogie (7) for transporting the sintering raw material in the gas communication relationship with the plurality of wind (9) and the wind (9) to suck the air required for the sintering reaction In the iron ore sintering apparatus comprising a main air pipe 150 to be installed, the line, the rear end of the main air pipe 150 is blocked; A portion of the main exhaust pipe 150 corresponding to the reference position at which the exhaust gas temperature rises rapidly is blocked by the blocking port 151 to form the first main exhaust pipe 150a and the second exhaust pipe 150b; A hood 170 configured to surround the sintered bogie 7 is installed at an upper portion of the sintered bogie 7 from a rear end of the sintering machine to a reference position at which the exhaust gas temperature rises rapidly; The first main exhaust pipe (150a) and the second exhaust pipe (150b) are connected in gas communication via the exhaust gas recirculation device (180); The hood 170 is connected in gas communication to the chimney through the gas discharge pipe 190; And exhaust gas circulation type iron ore sintering apparatus, characterized in that the dust collector 161 is installed in the gas discharge pipe (190). The exhaust gas recirculation pipe (181) of claim 4, wherein one end of the exhaust gas recirculation device (180) is connected to the main exhaust pipe (150) between the first blocking port (51) and the second blocking port (52), The second dust collector 182 and the circulation fan 183 installed in the exhaust gas extraction pipe 181, one end of the exhaust gas extraction pipe 181, the other end between the second shut-off port 52 and the rear end of the main exhaust pipe Exhaust gas circulation type iron ore sintering apparatus comprising a circulating gas injection pipe 184 connected to the main exhaust pipe. The exhaust gas circulation type iron ore sintering apparatus according to claim 4 or 5, wherein the gas discharge pipe (190) is provided with a boiler (191) for recovering sensible heat of hot exhaust gas.