KR20090130471A - Apparatus for injecting a fuel and apparatus for manufacturing molten iron comprising the same - Google Patents

Abstract

PURPOSE: A fuel injector and a molten iron manufacturing apparatus including the fuel injector are provided to distribute fuel more efficiently by coal ash and gas inlet pipes installed on a tuyere and therefore reduce fuel cost. CONSTITUTION: A fuel injector comprises a tuyere(101) which is installed in a furnace(100) to let gas into the furnace, a coal ash inlet pipe(103) which is installed in the tuyere to supply coal ash flowing in with air, and a gas inlet pipe(105) which is installed in the tuyere to supply hydrocarbon containing gas flowing in with the coal ash. In the gas inlet pipe, the supply direction and the inflow direction of hydrocarbon containing gas are crossed each other.

Description

Fuel injection device and molten iron manufacturing device including the same {APPARATUS FOR INJECTING A FUEL AND APPARATUS FOR MANUFACTURING MOLTEN IRON COMPRISING THE SAME}

The present invention relates to a fuel injection device and a molten iron manufacturing apparatus including the same. More specifically, the present invention relates to a fuel injection device for improving the combustibility of the fine coal ash and a molten iron manufacturing apparatus including the same.

For the production of molten iron, a blast furnace method or a melt-reducing steel method is being studied. In the blast furnace method or the molten reduction steelmaking method, molten iron is produced by charging iron ore and coal into a blast furnace or a molten gas furnace, respectively.

In order to minimize the amount of coal used in the blast furnace method or the molten reduction steelmaking method, pulverized coal is injected into the blast furnace or melt gasification furnace. Pulverized coal is charged into the blast furnace or a gas furnace installed in a molten gas furnace, and burned. As the pulverized coal is burned, combustion heat is generated and molten iron ore is melted by the combustion heat to produce molten iron. The coal charged from the top of the blast furnace or melt gasifier does not reach the bottom of the blast furnace or melt gasifier and is burned off in the middle. Therefore, in order to manufacture molten iron, it is effective to blow pulverized coal into the bottom of a blast furnace or a melt gasification furnace.

It is an object of the present invention to provide a fuel injection device that improves combustibility of fine coal ash. In addition, to provide a molten iron manufacturing apparatus including the above-described fuel blowing device.

The fuel injection device according to an embodiment of the present invention includes: i) a tuyere that is installed in a furnace and blows gas containing oxygen into the furnace; and ii) a tuyere that is installed in a tuyere and blown with air. And iii) a gas blowing pipe which is installed in the air pit and supplies a hydrocarbon-containing gas blown with the fine coal ash. The supply direction of the hydrocarbon containing gas in the gas blowing pipe and the blowing direction of the hydrocarbon containing gas cross each other.

One end of the gas blown pipe is sealed, and one or more openings are formed at one side of the gas blown pipe so that hydrocarbon-containing gas can be blown from the opening. The opening blows the hydrocarbon containing gas toward one end of the pulverized coal ash blowing pipe, and the hydrocarbon containing gas can be mixed with the pulverized coal ash blown from the pulverized coal ash blowing pipe. The Reynolds number of the hydrocarbon-containing gas blown may be 2320 to 4000.

One or more openings may include a plurality of openings. The sum of the cross-sectional areas of the plurality of openings may be substantially the same as the cross-sectional area of the gas blown pipe. The plurality of openings may be arranged regularly.

The diameter of the opening may be 5mm to 15mm. One end of the gas blown pipe may protrude deeper toward the interior of the furnace than one end of the pulverized coal ash blown pipe. The hydrocarbon-containing gas may include liquefied natural gas.

The apparatus for manufacturing molten iron according to an embodiment of the present invention includes a fuel injection device for supplying fuel for manufacturing molten iron, i) a furnace for manufacturing molten iron, and ii) a furnace. The fuel injection device includes: i) a tuyere which is installed in the furnace and blows gas containing oxygen into the furnace, ii) a tuyere, which is provided in a tuyere, and supplies a pulverized coal ash which is supplied with air to the pulverized coal ash; And a gas blowing pipe which is installed to supply a hydrocarbon-containing gas that is blown with the fine coal ash. The supply direction of the hydrocarbon containing gas in the gas blowing pipe and the blowing direction of the hydrocarbon containing gas cross each other.

One end of the gas blown pipe is sealed, and one or more openings are formed at one side of the gas blown pipe so that hydrocarbon-containing gas can be blown from the opening. The opening blows the hydrocarbon containing gas toward one end of the pulverized coal ash blowing pipe, and the hydrocarbon containing gas can be mixed with the pulverized coal ash blown from the pulverized coal ash blowing pipe. The Reynolds number of the hydrocarbon-containing gas blown may be 2320 to 4000.

The furnace may be a blast furnace or a melt gasification furnace. When the furnace is a melt gasifier, the molten iron manufacturing apparatus may further include a fluidized bed reduction furnace or a packed bed reduction furnace for supplying reduced iron to the melt gasifier.

The fuel injector can be used to improve the dispersibility and combustibility of the pulverized coal ash. Therefore, the fuel cost of the molten iron manufacturing apparatus can be reduced, and efficient operation can be performed.

With reference to the accompanying drawings, it will be described embodiments of the present invention to be easily implemented by those skilled in the art. As can be easily understood by those skilled in the art, the embodiments described below may be modified in various forms without departing from the concept and scope of the present invention. Where possible the same or similar parts are represented with the same reference numerals in the drawings.

All terms including technical terms and scientific terms used below have the same meaning as those commonly understood by those skilled in the art. Terms defined in advance are additionally interpreted to have a meaning consistent with the related technical literature and the presently disclosed contents, and are not interpreted in an ideal or very formal sense unless defined.

As used herein, the term "blowing" refers to an operation of exiting from the inside of a specific pipe and outward of the specific pipe. In addition, the term "supply" as used below refers to an operation provided while flowing inside the specific pipe.

1 schematically illustrates a furnace 100 included in a molten iron manufacturing apparatus 1000 according to a first embodiment of the present invention. 1 except for the furnace 100 included in the apparatus for manufacturing molten iron 1000, the illustration is omitted for convenience. Here, the furnace 100 means a blast furnace, and for the sake of convenience, the furnace 100 will be referred to as a blast furnace 100 below.

As shown in FIG. 1, the blast furnace 100 is provided with a fuel injection device 10, a tapping hole 12, and a charging chute 14. The gas containing the oxygen, the fine coal ash, and the hydrocarbon-containing gas are supplied into the blast furnace 100 through the fuel injection device 10. In addition, sintered ore and coke are charged into the blast furnace 100 through the charging chute 14. Sintered ore and coke are charged in the form of a mixture to form a layer evenly distributed in the blast furnace 100. Therefore, the heat exchange between the sintered ore and the coke is made smoothly. The coke forms a coke filling layer 100a inside the blast furnace 100.

Examples of the gas containing oxygen include hot air. Here, the gas containing oxygen includes a case where the gas consists only of pure oxygen or the gas contains pure oxygen. The hot air is blown into the blast furnace 100 through the fuel blowing device 10. Hot air may be used by mixing coke oven gas (COG). The hot air blown into the blast furnace 100 heats the coke-filled layer 100a to form a raceway 100b inside the blast furnace 100.

Meanwhile, the coke packed layer 100a melts the sintered ore while being heated at a high temperature to generate molten iron. The molten iron flows to the lower side of the blast furnace 100 and is discharged to the outside together with the slag through the hot water outlet 12. Hereinafter, the structure of the fuel injection device 10 of FIG. 1 will be described in more detail with reference to FIG. 2.

FIG. 2 is a schematic enlarged cross-sectional view of the fuel injection device 10 of FIG. 1. The structure of the fuel injection device 10 of FIG. 2 is merely for illustrating the present invention, and the present invention is not limited thereto. Therefore, the structure of the fuel injection device 10 can be modified in various forms.

As shown in FIG. 2, the fuel injection device 10 includes a tuyere 101, a pulverized coal ash injection pipe 103, and a gas injection pipe 105. In addition, the fuel injection device 10 may further include other devices.

The tuyere 101 is installed in the blast furnace 100. Air, for example, hot air, is blown into the blast furnace 100 through the tuyere 101. The pulverized coal ash injection pipe 103 and the gas injection pipe 105 pass through the air vent 101 and are installed inside the air vent 101. Therefore, the pulverized coal ash and the hydrocarbon-containing gas can be blown into the blast furnace 100 through the tuyere 101.

The pulverized coal ash injection pipe 103 is provided in the tuyere 101. The pulverized coal ash injection pipe 103 supplies the pulverized coal ash to be blown into the blast furnace 100. Here, pulverized coal, pulverized coke, etc. can be used as a pulverized coal material. The pulverized coal ash is mixed with the hot air supplied through the tuyere 101 and blown into the blast furnace 100 together with the hot air.

The gas blowing pipe 105 is installed in the tuyere 101. The gas blowing pipe 105 supplies a hydrocarbon-containing gas and blows it into the blast furnace 100. The hydrocarbon-containing gas may include liquid natural gas (LNG) and the like. The hydrocarbon-containing gas is mixed with the pulverized coal ash and blown into the blast furnace 100 together with the pulverized coal ash.

As shown by the arrow on the left side of FIG. 2, the hydrocarbon-containing gas is supplied toward the inside of the blast furnace 100 through the gas blowing pipe 105. The hydrocarbon-containing gas supplied through the gas blowing pipe 105 is blown toward the one end 1031 of the pulverized coal ash injection pipe 103 inside the blast furnace 100, as shown by the right arrow of FIG. 2. That is, the supply direction in the gas blowing pipe 105 of hydrocarbon containing gas and the blowing direction of hydrocarbon containing gas cross | intersect mutually.

As shown in Fig. 2, since the hydrocarbon-containing gas is supplied toward the pulverized coal ash blown in from the pulverized coal ash blowing pipe 103, the hydrocarbon-containing gas can be mixed with the pulverized coal ash to burn the pulverized coal ash well. Therefore, the pulverized coal ash may be prevented from being unburned and the combustion heat inside the blast furnace 100 may be increased.

As shown in FIG. 2, one end 1051 of the gas injection pipe 105 protrudes deeper toward the inside of the blast furnace 100 than the one end 1031 of the pulverized coal ash injection pipe 103. Therefore, most of the pulverized coal ash blown in from the pulverized coal ash blowing pipe 103 can be mixed with the hydrocarbon-containing gas blown through the gas blowing pipe 105. Therefore, the combustion efficiency of pulverized coal ash can be greatly increased.

FIG. 3 is a schematic enlarged view of a portion III of FIG. 2. 3 shows only the pulverized coal ash blowing pipe 103 and the gas blowing pipe 105, and the rest of the drawing is omitted for convenience.

As shown in FIG. 3, one end 1051 of the gas injection pipe 105 is sealed and blocked. Instead, the hydrocarbon-containing gas supplied through the gas blowing tube 105 is blown into the blast furnace 100 (shown in FIG. 1) through the plurality of openings 1053. Since the hydrocarbon-containing gas is blown through the plurality of openings 1053, the hydrocarbon-containing gas may form turbulence to diffuse the fine coal powder well. Therefore, the dispersibility of the pulverized coal ash flowing into the blast furnace 100 (shown in FIG. 1) can be maximized, and the area of the pulverized coal ash mixed with the hydrocarbon-containing gas can be increased, thereby improving the combustibility of the pulverized coal ash. To this end, the Reynolds number of the hydrocarbon-containing gas blown described in Equation 1 below may be 2320 to 4000. Here, the Reynolds number has a dimensionless unit.

Re = D × υ × ρ / μ = D × υ / ν

D: diameter of gas blowing pipe (d1) (m)

υ: flow rate of hydrocarbon-containing gas (m / sec)

ρ: density of hydrocarbon-containing gas (kg / m ² )

μ: viscosity of hydrocarbon-containing gas (kg / msec)

ν: kinematic viscosity of hydrocarbon-containing gas (m ² / sec) (= μ / γ)

γ: specific weight (kg / m ³ )

If the Reynolds number is less than 2320, laminar flow is generated rather than turbulent, so that the hydrocarbon-containing gas does not mix well with the pulverized coal. Conversely, if Reynolds exceeds 4000, the hot air may not blow well into the blast furnace 100 (shown in FIG. 2) due to excessive turbulence generation.

As shown in FIG. 3, the plurality of openings 1053 are regularly arranged while keeping their distances constant. Therefore, the hydrocarbon-containing gas can be uniformly supplied through the plurality of openings 1053.

Openings 1053 are formed in side surface 1055 of gas blown pipe 105 located near one end 1051 of gas blown pipe 105. Accordingly, the hydrocarbon-containing gas may be blown through the openings 1053.

As indicated by arrows in FIG. 3, the openings 1053 blow the hydrocarbon-containing gas supplied from the gas blowing pipe 105 toward one end 1031 of the pulverized coal ash blowing pipe 103. Therefore, the hydrocarbon-containing gas is mixed with the pulverized coal ash blown from one end 1031 of the pulverized coal ash injection pipe 103 to burn the pulverized coal ash. As a result, the combustibility of the pulverized coal ash can be improved.

The diameter d2 of the opening 1053 may be 5 mm to 15 mm. When the diameter d2 of the opening 1053 is less than 5 mm, a sufficient amount of hydrocarbon-containing gas cannot be blown, and the blowing flow rate of the hydrocarbon-containing gas is so fast that the melt around the openings 1053 can be melted. On the contrary, when the diameter d2 of the opening 1053 exceeds 15 mm, a large amount of hydrocarbon-containing gas may be supplied at one time and the surroundings of the openings 1053 may be melted. Therefore, the diameter d2 of the opening portion 1053 can be set within the above range.

As shown in FIG. 3, the sum of the cross-sectional areas [(d2) ² π / 4] of the plurality of openings 1053 is substantially the same as the cross-sectional area [(d1) ² π / 4] of the gas blowing pipe 105. can do. Therefore, the same amount of hydrocarbon-containing gas as when the one end 1051 of the gas injection pipe 105 is opened can be blown in through the plurality of openings 1053.

Furthermore, as described in Equation 2 below, the flow rate of the hydrocarbon-containing gas is proportional to the flow rate at the time of blowing the hydrocarbon-containing gas, so that the flow rate at the time of blowing the hydrocarbon-containing gas can be adjusted by adjusting the flow rate of the hydrocarbon-containing gas. have.

Flow rate of hydrocarbon-containing gas = sum of the cross-sectional areas of the openings x flow rate at blowing of hydrocarbon-containing gas

4 schematically shows an operating state of the fuel injection device 10 of FIG. As shown in FIG. 4, a combustion zone 100b is formed at the tip of the fuel injection device 10, that is, inside the blast furnace 100.

As shown in FIG. 4, the combustion zone 100b includes an oxidation zone 100b1 and a direct solution loss 100b2. In the oxidation zone 100b1, carbon is reacted with oxygen to generate carbon monoxide as shown in Scheme 1 below. In addition, in the direct reduction band 100b2, carbon monoxide is generated by reacting carbon with carbon dioxide as in Scheme 2 below. Carbon reacts with water to produce carbon monoxide and hydrogen. Therefore, since the amount of hydrogen in the reducing gas is increased, the oxygen loading rate in the reducing gas is increased. As a result, molten iron production can be increased.

C + 1 / 2O ₂ → CO

C + CO ₂ → 2CO

C + H ₂ O → CO + H ₂

Here, as the direct reduction zone 100b2 is located closer to the tuyere 101, the possibility that the tuyere 101 is melted is increased. However, in the first embodiment of the present invention, the pulverized coal ash and the hydrocarbon-containing gas are blown together to maximize the width of the oxidation zone 100b1. Therefore, the oxidation zone 100b1 increases the distance between the direct reduction zone 100b2 and the tuyere 101 to separate the direct reduction zone 100b2 and the tuyere 101 from each other. As a result, the melt loss phenomenon of the tuyere 101 can be prevented.

In particular, by injecting a hydrocarbon-containing gas toward the pulverized coal ash blown, the oxidation zone 100b1 can be expanded while maximizing the dispersion of the hydrocarbon-containing gas. Therefore, the unburned char loss reaction amount increases, and the coke melt loss reaction amount decreases. In addition, the formation of the deterioration layer is reduced, and the combustibility of the pulverized coal material is improved. As a result, the amount of coke powder is reduced and the amount of coke powder accumulated in the core of the blast furnace 100 can be reduced to improve the air permeability of the bottom of the blast furnace 100.

If only pulverized coal is blown, the deteriorated coke wears and is thermally shocked while turning the combustion zone 100b in the direct reduction zone 100b2. Worn and thermally impacted coke is differentiated. In this case, the oxidation zone 100b1 is narrowed, which reduces the possibility of consuming the differentiated coke. Therefore, the amount of differentiated coke is increased and the air permeability of the blast furnace 100 lowers.

In addition, when pulverized coal and liquefied natural gas are blown in, and the supply direction and injection direction of liquefied natural gas are the same, pulverized coal is blown into the blast furnace 100 parallel to the feed direction. In this case, since the width of the oxidation zone 100b1 is small, the amount of direct reduction of unburned fuel is reduced and the amount of direct reduction of coke is increased. Therefore, as the deterioration layer increases, the combustibility of pulverized coal decreases. As a result, the amount of differentiated coke increases and the core accumulation of the differentiated coke increases. Therefore, the air permeability of the bottom of the blast furnace 100 is deteriorated.

On the other hand, in the first embodiment of the present invention, turbulence is formed due to the blowing direction of the hydrocarbon-containing gas, thereby maximizing dispersibility and combustibility of the pulverized coal ash. Therefore, it is possible to improve the air permeability of the blast furnace 100 by minimizing the amount of dust generated in the combustion zone (100b).

5 schematically shows a molten iron manufacturing apparatus 2000 according to a second embodiment of the present invention. Since the fuel injection device 10 included in the apparatus for manufacturing molten iron 2000 of FIG. 5 is the same as the fuel injection device 10 of FIG. 2, the same reference numerals are used, and detailed description thereof will be omitted. In addition, since the furnace 200 of FIG. 5 means a melt gasifier, the furnace 200 will be referred to as a melt gasifier 200 for convenience.

As shown in FIG. 5, the apparatus for manufacturing molten iron 2000 includes a plurality of fluidized-bed reduction reactors 60, a reducing gas supply pipe 70, a compacted material manufacturing apparatus 40, and a melt gasification furnace 200. . In addition, the molten iron manufacturing apparatus 2000 may further include a high temperature uniform back pressure device 50 for transferring the compacted material manufactured by the compacted material manufacturing apparatus 40 to the melt gasifier 200. The high temperature uniform back pressure device 50 pumps the compacted body manufactured by the compacted body manufacturing apparatus 40 to the molten gasifier 200. The compacted material manufacturing apparatus 40 and the high temperature uniform back pressure apparatus 50 may not be installed.

In the apparatus for manufacturing molten iron 2000, iron ore may be used. If necessary, the molten iron manufacturing apparatus 2000 may further use additional materials. A fluidized bed is formed inside the fluidized bed reduction furnace 60 to reduce iron ore. The fluidized-bed reduction reactor 60 includes a first fluidized-bed reduction reactor 601, a second fluidized-bed reduction reactor 603, a third fluidized-bed reduction reactor 605, and a fourth fluidized-bed reduction reactor 607. . Although four fluidized-bed reduction reactors 60 are shown in FIG. 5, these are merely to illustrate the present invention and the present invention is not limited thereto. Therefore, three fluidized bed reduction furnaces may be used.

The first fluidized-bed reduction reactor 601 preheats the iron ore with the reducing gas discharged from the second fluidized-bed reduction reactor 603. The second fluidized-bed reduction reactor 603 and the third fluidized-bed reduction reactor 605 preliminarily reduce preheated iron ore. The fourth fluidized bed reduction furnace 607 finally converts the preliminarily reduced iron ore into a reducing body.

Iron ore is reduced and heated while passing through the fluidized-bed reduction reactor (60). To this end, the reducing gas generated in the melt gasifier 200 is supplied to the fluidized bed reduction furnace 60 through the reducing gas supply pipe 70. The reduced iron ore is made of compacted material through the compacted material manufacturing apparatus 40.

The compacted material manufacturing apparatus 40 includes the charging hopper 401, a pair of roll 403, the crusher 405, and the storage tank 407. In addition, the compacted material manufacturing apparatus 40 may further include another apparatus as needed. The charging hopper 401 stores the reduced iron ore while passing through the fluidized-bed reduction reactor 60. Iron ore is press-molded in strip form while being charged from the charging hopper 401 into a pair of rolls 403. The iron ore press-molded in this manner is crushed in the crusher 405 and stored as a compact in the storage tank 407.

The bulk coal is charged into the melt gasifier 200 to form a coal-filled layer (not shown) inside the melt gasifier 200. The bulk coal material includes lump coal or coal briquettes. Coal briquettes are manufactured by press-molding fine coal. In addition, coke may be charged into the molten gasifier 200 as necessary. Air, for example, oxygen blown into the fuel injector 10 forms a combustion zone by heating the coal packed bed, and melts the compacted material, ie, reduced iron, to produce molten iron.

As shown in FIG. 5, in the second embodiment of the present invention, the pulverized coal ash and the hydrocarbon-containing gas are supplied through the fuel blowing device 10, and turbulence is generated by the hydrocarbon-containing gas blown to disperse the pulverized coal ash and Improves combustibility. Therefore, it is possible to minimize the fuel cost of the molten iron manufacturing apparatus (2000).

6 shows a molten iron manufacturing apparatus 3000 according to a third embodiment of the present invention. In the molten iron manufacturing apparatus 3000 of FIG. 6, the furnace 200, the fuel injection device 10, and the reducing gas supply pipe 70 are respectively a melt gasifier 200, a fuel injection device 10, and a reducing gas supply pipe of FIG. 5. Since it is the same as 70, the same reference numerals are used and the detailed description thereof is omitted.

The apparatus for manufacturing molten iron 3000 of FIG. 6 includes a packed-bed reduction furnace 30 and a melt gasifier 200. In addition, the apparatus for manufacturing molten iron 3000 may further include other devices. In the packed-bed reduction furnace 30, iron ore is charged and reduced. If necessary, secondary raw materials may be further used in the packed-bed reduction reactor 30. The iron ore to be charged into the packed-bed reduction furnace 30 is pre-dried in a bulk form. Iron ore is converted into a reducing body while passing through the packed-bed reduction reactor (30). The packed-bed reduction reactor 30 receives the reducing gas from the melt gasifier 200 through the reduction gas supply pipe 70 to form a packed bed therein. Iron ore passes through a packed bed and is converted into a reducing body.

As shown in FIG. 6, in the third embodiment of the present invention, the pulverized coal ash and the hydrocarbon-containing gas are supplied to the molten gasifier 200 through the fuel blowing device 10, and the turbulence is blown by the hydrocarbon-containing gas. To improve the dispersibility and combustibility of the pulverized coal ash. Therefore, the fuel cost of the apparatus for manufacturing molten iron 3000 may be minimized.

Although the present invention has been described above, it will be readily understood by those skilled in the art that various modifications and variations are possible without departing from the spirit and scope of the claims set out below.

1 is a schematic diagram of an apparatus for manufacturing molten iron according to a first embodiment of the present invention.

FIG. 2 is a schematic enlarged cross-sectional view of the fuel injection device of FIG. 1.

FIG. 3 is a schematic enlarged view of portion III of FIG. 2.

4 is a view schematically showing an operating state of the fuel injection device of FIG.

5 is a schematic diagram of an apparatus for manufacturing molten iron according to a second embodiment of the present invention.

6 is a schematic diagram of a molten iron manufacturing apparatus according to a third embodiment of the present invention.

Claims (16)

A tuyere which is installed in a furnace and blows gas containing oxygen into the furnace; A pulverized coal ash blowing pipe which is installed in the tuyere and supplies pulverized coal ash blown together with the air; and A gas blowing pipe which is installed in the tuyere and supplies a hydrocarbon-containing gas blown with the fine coal ash; Including, And a direction in which the supply direction of the hydrocarbon-containing gas in the gas intake pipe and the intake direction of the hydrocarbon-containing gas cross each other. The method of claim 1, One end of the gas injection pipe is sealed, one or more openings are formed on one end side of the gas injection pipe so that the hydrocarbon-containing gas is blown from the opening. The method of claim 1, And the opening blows the hydrocarbon-containing gas toward one end of the pulverized coal ash blowing pipe, and the hydrocarbon-containing gas is mixed with the pulverized coal ash blown in from the pulverized coal ash blowing pipe. The method of claim 3, Reynolds number of the blown hydrocarbon-containing gas is 2320 to 4000 fuel injection device. The method of claim 1, And the at least one opening comprises a plurality of openings. The method of claim 5, And the sum of the cross-sectional areas of the plurality of openings is substantially the same as the cross-sectional area of the gas blowing pipe. The method of claim 6, And the plurality of openings are arranged regularly. The method of claim 1, The diameter of the opening is 5mm to 15mm fuel injection device. The method of claim 1, One end of the gas blowing pipe protrudes deeper toward the inside of the furnace than one end of the pulverized coal ash blowing pipe. The method of claim 1, The hydrocarbon-containing gas fuel injection device comprising a liquefied natural gas. Furnace for manufacturing molten iron, and A fuel injection device installed in the furnace and supplying fuel for manufacturing the molten iron; As molten iron manufacturing apparatus comprising: The fuel injection device, A tuyere installed in the furnace to blow gas containing oxygen into the furnace, A pulverized coal ash blowing pipe which is installed in the tuyere and supplies pulverized coal ash blown together with the air; and A gas blowing pipe which is installed in the tuyere and supplies a hydrocarbon-containing gas blown with the fine coal ash; Including, And a direction in which the supply direction of the hydrocarbon-containing gas in the gas intake pipe and the intake direction of the hydrocarbon-containing gas cross each other. The method of claim 11, One end of the gas injection pipe is sealed, one or more openings are formed on one end side of the gas injection pipe so that the hydrocarbon-containing gas is blown from the opening. The method of claim 11, And the opening blows the hydrocarbon-containing gas toward one end of the pulverized coal ash blowing pipe, and the hydrocarbon-containing gas is mixed with the pulverized coal ash blown from the pulverized coal ash blowing pipe. The method of claim 13, Reynolds number of the blown hydrocarbon-containing gas is 2320 to 4000 fuel injection device. The method of claim 11, The furnace is an apparatus for producing molten iron, which is a blast furnace or a melt gasification furnace. The method of claim 15, When the furnace is a melt gasifier, the molten iron manufacturing apparatus further comprises a fluidized bed reduction furnace or a packed bed reduction furnace for supplying reduced iron to the molten gasifier.

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