KR101235252B1 - Method for manufacturing molten irons by injecting a hydrocarbon gas and apparatus for manufacturing molten irons using the same - Google Patents

Abstract

The present invention relates to a method for producing molten iron by blowing a hydrocarbon-containing gas and an apparatus for producing molten iron using the same. The method for manufacturing molten iron according to the present invention comprises the steps of converting iron ore into a reducing body while passing it through a reducing furnace, inserting a bulk coal material into a molten gasifier connected to the reducing furnace to form a coal-filled layer, and connecting the reducing body to the reducing furnace. Charging molten gasifier and blowing oxygen, steam, and hydrocarbon-containing gas together at the bottom of the coal packed bed to produce molten iron; and supplying reducing gas discharged from the molten gasifier to the reduction furnace. In the step of producing molten iron, steam is blown while preventing contact between oxygen and a hydrocarbon-containing gas.

Hydrocarbon-containing gas, blown, melt gasification furnace, steam

Description

METHOD FOR MANUFACTURING MOLTEN IRONS BY INJECTING A HYDROCARBON GAS AND APPARATUS FOR MANUFACTURING MOLTEN IRONS USING THE SAME}

1 is a view schematically showing a molten iron manufacturing apparatus according to a first embodiment of the present invention.

2 is a view schematically showing a molten iron manufacturing apparatus according to a second embodiment of the present invention.

3 is a conceptual diagram showing a blowing state of a hydrocarbon-containing gas.

Figure 4 is a cross-sectional view of the gas blowing device provided in the molten iron manufacturing apparatus according to an embodiment of the present invention.

The present invention relates to a method for manufacturing molten iron by blowing a hydrocarbon-containing gas, and a molten iron manufacturing apparatus using the same, and more particularly, by injecting a hydrocarbon-containing gas into a molten gas furnace to obtain a heat source necessary for melting the reduced iron, It relates to a molten iron manufacturing method and a molten iron manufacturing apparatus using the same.

The steel industry is a key industry that supplies basic materials to the entire industry, such as automobiles, shipbuilding, home appliances, construction, etc., and is one of the oldest industries with the development of mankind. Steel mills, which play a pivotal role in the steel industry, use molten iron and coal as raw materials to produce molten pig iron, which is then manufactured and supplied to each customer.

Currently, about 60% of the world's iron production comes from the blast furnace method developed since the 14th century. Blast furnace method is a method of manufacturing molten iron by reducing the iron ore to iron by putting together the coke prepared from the sintering process and the coke produced from the bituminous coal into the blast furnace. However, the blast furnace method requires a supplementary facility for the production of coke and sintered ore, and there is a serious problem of environmental pollution due to the supplementary facility.

In order to solve the problems of the blast furnace method, many countries around the world are putting a lot of effort into the development of the molten reduction steelmaking method. In the molten reducing steelmaking method, molten iron is produced in a molten gas furnace using direct coal as a fuel and a reducing agent, and ore directly as an iron source. Here, oxygen is blown through a plurality of tuyere provided on the outer wall of the melt gasifier to burn the coal-filled layer in the melt gasifier. Oxygen is converted to high-temperature reducing gas and sent to a fluid reduction reactor to reduce iron ore and discharged to the outside.

Coal such as lump coal or coal briquettes is charged into the melt gasifier. The cost of manufacturing depends on the amount of coal loaded. Therefore, iron ore with high reduction rate should be charged to the melt gasifier in order to minimize the amount of coal. To this end, high-quality reducing gas should be supplied to the flow reduction reactor to increase the reduction rate of iron ore as much as possible.

Iron ore may be reduced by using hydrogen (H ₂ ) and carbon monoxide (CO) contained in the reducing gas. Therefore, a large amount of hydrogen and carbon monoxide should be generated in a melt gasifier in which reducing gas is generated.

In the melt gasifier, lump coal and coal briquettes are charged to form a coal-filled layer, from which a reducing gas is generated. In the coal and coal briquettes, carbon and hydrogen are present in the form of carbon (C) and moisture (H ₂ O). Therefore, in order to completely gasify these components contained in the lump coal and coal briquettes, it is necessary to properly control the internal behavior of the melt gasification furnace. However, due to various variables, it is very difficult to properly control the internal behavior of the melt gasification. For example, some of the carbon components contained in the lump coal and the coal briquettes are oxidized to carbon dioxide (CO ₂ ) and the like, and thus there is a problem in that it cannot contribute to the reduction of iron ore at all.

The present invention is to solve the above-mentioned problems, to provide a molten iron manufacturing method that can improve the quality of the reducing gas while blowing the hydrocarbon-containing gas to increase the amount of reducing gas.

In addition, the present invention is to provide a molten iron manufacturing apparatus using the above-described molten iron manufacturing method.

The method for manufacturing molten iron according to the present invention comprises the steps of converting iron ore into a reducing body while passing it through a reducing furnace, inserting a bulk coal material into a molten gasifier connected to the reducing furnace to form a coal-filled layer, and connecting the reducing body to the reducing furnace. Charging molten gasifier and blowing oxygen, steam, and hydrocarbon-containing gas together at the bottom of the coal packed bed to produce molten iron; and supplying reducing gas discharged from the molten gasifier to the reduction furnace. In the step of producing molten iron, steam is blown while preventing contact between oxygen and a hydrocarbon-containing gas.

In the step of producing molten iron, the amount of oxygen is preferably at least two times the amount of the hydrocarbon-containing gas.

In the step of converting the iron ore into a reducing body, the reduction furnace may be a fluidized bed reduction furnace.

In the step of converting the iron ore into a reducing body, the reducing furnace may be a packed-bed reduction furnace.

In the step of producing molten iron, it is preferable that the steam reacts with the hydrocarbon-containing gas to generate a reducing gas.

In the apparatus for manufacturing molten iron according to the present invention, a reduction furnace for reducing iron ore and converting it into a reducing body, the bulk coal is charged therein to form a coal filling layer and injecting oxygen, steam and hydrocarbon-containing gas together at the bottom of the coal filling layer. A melt gasification furnace is connected to a reduction furnace and connected with a reduction furnace to produce a molten iron, and a reducing gas supply pipe for supplying the reducing gas discharged from the melting gasification furnace to the flow reduction reactor. Steam is blown while preventing contact between oxygen and hydrocarbon containing gas.

It is preferable that a through hole is formed in the tuyere, and a double tube is inserted into the through hole.

The double tube includes an inner tube and an outer tube surrounding the inner tube, and may blow steam between the inner tube and the outer tube.

Hydrocarbon-containing gas can be blown in through the inner tube.

Oxygen can be blown through the through hole outside the double tube.

It is preferable that the end of the tuyere on the melt gasifier side and the end of the double pipe are located on the same line.

The amount of oxygen is preferably at least two times the amount of the hydrocarbon-containing gas.

The reduction furnace may be a fluidized bed reduction furnace.

The reduction furnace may be a packed bed reduction furnace.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 4. These embodiments are only for illustrating the present invention, and the present invention is not limited thereto.

1 shows a molten iron manufacturing apparatus 100 according to a first embodiment of the present invention. The apparatus for manufacturing molten iron 100 shown in FIG. 1 is merely for illustrating the present invention, but the present invention is not limited thereto. Therefore, the apparatus for manufacturing molten iron 100 may be modified in another form.

The molten iron manufacturing apparatus 100 shown in FIG. 1 includes a reduction furnace 30 and a melt gasification furnace 60. Other devices may also be included if desired. In the reduction furnace 30 is charged by reducing the iron ore. Subsidiary materials may be used as needed. Iron ore to be charged into the reduction furnace 30 is pre-dried in the form of a block. Iron ore is converted into a reducing body while passing through the reduction furnace (30). Reduction furnace 30 is a packed-bed reduction reactor, receives a reducing gas from the melt gasifier 60 to form a packed bed therein. Iron ore passes through a packed bed and is converted into a reducing body.

The bulk carbonaceous material is charged from the upper portion of the melt gasifier 60 to form a coal filling layer therein. The bulk coal material includes lump coal or coal briquettes. Coal briquettes are manufactured by press-molding pulverized coal. In addition, coke may be charged as needed. A plurality of tuyere 601 is provided on the outer wall of the melt gasifier 60 to blow hydrocarbon-containing gas (A), steam (B) and oxygen (C) together. Hydrocarbon containing gas (A) means all the gas containing a hydrocarbon, for example, LNG (liquid natural gas, liquefied natural gas). Hydrocarbon-containing gas (A), steam (B) and oxygen (C) are blown into the lower part of the coal packed bed to burn the coal packed bed, which is advantageous for reducing gas generation. In addition, since the hydrocarbon-containing gas (A), vapor (B) and oxygen (C) are blown together, the tuyere can be cooled while increasing the amount of reducing gas by mutual reaction between them.

The reduced body reduced in the reduction furnace 30 is charged through the upper part of the melt gasifier 60 and melted while passing through the coal filling layer. In this way molten iron can be produced. A hot water outlet is installed in the lower portion of the melt gasifier 60 to discharge molten iron and slag to the outside.

A reducing gas containing hydrogen and carbon monoxide is generated from the coal-filled layer formed inside the melt gasifier 60. Since the upper portion of the melt gasifier 60 is formed in a dome shape, it is advantageous for generating reducing gas. The reducing gas discharged from the melt gasifier 60 is supplied to the reduction furnace 30 through the reduction gas supply pipe 70. Therefore, iron ore can be reduced and calcined with a reducing gas.

2 shows a molten iron manufacturing apparatus 200 according to a second embodiment of the present invention. Since the molten gasifier 60 shown in FIG. 2 is the same as the molten gasifier shown in FIG. 1, the same reference numerals are used and detailed description thereof will be omitted.

The apparatus for manufacturing molten iron 200 includes one or more flow reduction reactors 20, a melt gasifier 60, a reducing gas supply pipe 70, and a compacted material manufacturing apparatus 40. In addition, the high temperature homogenizing device 50 for transferring the compacted material manufactured by the compacted material manufacturing apparatus 40 to the melt gasifier 60 may be further included. The high temperature uniform pressure-reducing apparatus 50 presses the compacted body manufactured by the compacted body manufacturing apparatus 40 to the molten gasifier 60. The compacted material manufacturing apparatus 40 and the high temperature uniform back pressure apparatus 50 can be omitted as needed.

The molten iron manufacturing apparatus 200 has an advantage that can use the iron ore. Subsidiary materials may be used as needed. A fluidized bed is formed inside the fluid reduction path 20 to reduce iron ore. The flow reduction path 20 includes a first flow reduction path 201, a second flow reduction path 203, a third flow reduction path 205, and a fourth flow reduction path 207. Although four flow reduction paths 20 are shown in FIG. 1, these are merely to illustrate the present invention and the present invention is not limited thereto. Therefore, three flow reduction reactors may be used.

The first flow reduction path 201 preheats the iron ore with reducing gas discharged from the second flow reduction path 203. The second flow reduction path 203 and the third flow reduction path 205 preliminarily reduce the preheated iron ore. The fourth flow reduction reactor 207 converts the preliminarily reduced iron ore into a reducing body.

Iron ore is reduced and heated while passing through the fluid reduction path (20). To this end, the reducing gas generated in the melt gasifier 60 is supplied to the flow reduction path 20 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, other devices may be further included as necessary. The charging hopper 401 stores the reduced iron ore while flowing through the flow reduction path 20. Iron ore is press-molded in the form of a strip 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.

3 schematically shows a state in which hydrocarbon-containing gas (A), steam (B) and oxygen (C) are blown from the tuyere 601.

The double pipe 603 is inserted into the through hole 6015 formed in the tuyere 601. The double pipe 603 may be, for example, a lance. The double tube 603 includes an inner tube 6031 and an outer tube 6033 surrounding the inner tube 6031. Therefore, three spaces are formed including the through hole 6015 of the double tube 603, between the inner tube 6031 and the outer tube 6033, and the inside of the inner tube 6031. Therefore, different gases may be supplied to three spaces and blown into the molten gasifier 60.

In the present invention, the hydrocarbon-containing gas (A), steam (B) and oxygen (C) are blown together. By blowing the hydrocarbon-containing gas (A), the amount of reducing gas can be increased to improve the reduction rate of iron ore. Therefore, it is possible to reduce the amount of the bulk carbonaceous material charged in the melt gasifier (60). Moreover, the temperature of a combustion zone can be managed stably by blowing in hydrocarbon-containing gas (A). Therefore, it is possible to improve the quality of molten iron by significantly lowering the silicon (Si) content in the molten iron. In addition, the amount of carbon dioxide generated can be greatly reduced by blowing the hydrocarbon-containing gas (A).

In the present invention, the vapor (B) is used to prevent the oxygen (C) and the hydrocarbon-containing gas (A) from being directly contacted with each other. Therefore, the hydrocarbon-containing gas (A) is complexed by the oxygen (C), it is possible to prevent the phenomenon that the end of the tuyere 601 and the end of the double pipe 603 is not dissolved. That is, since the combustion focus is spaced 1 cm or more from the end of the tuyere 601 toward the inside of the molten gasifier 60, the end of the tuyere 601 and the end of the double tube 603 by the heat of combustion can be prevented. For this purpose, as shown in FIG. 3, the hydrocarbon containing gas A is blown in through the inner pipe 6031, and steam B is blown in between the inner pipe 6031 and the outer pipe 6033. As shown in FIG. On the other hand, oxygen (C) is blown in through the through-hole 6015 outside the double pipe 603. Since oxygen (C) must be blown in a large amount to form a combustion zone in the coal packed bed, it is preferable to be blown through the through hole 6015 having a relatively large space. It is preferable that the quantity of oxygen (C) blown in is 2 times or more of the quantity of hydrocarbon containing gas (A). When the amount of oxygen (C) is less than twice the amount of the hydrocarbon-containing gas (A), the amount of oxygen (A) is absolutely insufficient and stable combustion is hardly achieved.

This gas blowing method is merely for illustrating the present invention, and the present invention is not limited thereto. Therefore, it is possible to prevent the oxygen (C) and the hydrocarbon-containing gas (A) from being blown in contact with each other by the steam (B) by using a tuyere of another structure.

On the other hand, as shown in FIG. 3, it is preferable that the edge part of the tuyere 601 toward the molten gasifier 60 side is located on the same line P as the edge part of the double pipe 603. As shown in FIG. When the end of the double tube 603 is located behind the end of the tuyere 601, oxygen (C) and hydrocarbon-containing gas (A) are in direct contact with each other to cause ignition of the hydrocarbon-containing gas (A). There is a high possibility that the end is melted. On the contrary, when the end of the double pipe 603 is located ahead of the end of the tuyere 601, the double pipe 603 may be damaged by the impact of the charges inside the melt gasifier (60).

Since the steam (B) is in direct contact with the hydrocarbon-containing gas (C), it reacts with each other to produce a reducing gas. The reaction process is shown in the following formula (1).

CH ₄ + H ₂ 0 → CO + 3 H ₂ , ΔH = + 228,000 kJ / kg-mol

CH ₄ here is the main component of the hydrocarbon-containing gas (C). As described in Formula 1, the vapor (B) is in contact with the hydrocarbon-containing gas (C) to cause an endothermic reaction that absorbs the surrounding heat while being decomposed into carbon monoxide and hydrogen. Therefore, since the heat load received by the tuyere 601 and the double tube 603 can be reduced, it is possible to prevent the tuyere 601 and the double tube 603 from deterioration or melting.

And steam (B) is a hydrocarbon-containing gas (C) generates a large amount of carbon monoxide and hydrogen by mutual contact. Particularly, since hydrogen having excellent reducing power as compared to carbon monoxide generates about three times as much as carbon monoxide, it is advantageous for reducing iron ore.

Figure 4 shows a cross-sectional structure of the gas blowing device 80 provided in the molten iron manufacturing apparatus according to an embodiment of the present invention. The structure of the gas blowing device 80 shown in FIG. 4 is merely for illustrating the present invention, and the present invention is not limited thereto. Therefore, the structure of the gas blowing device 80 can be modified in other forms.

Hydrocarbon-containing gas (A), steam (B) and oxygen (C) can be blown together through the gas blowing device (80). The gas blowing device 80 includes a tuyere 601 and a double pipe 603. In addition, the gas blowing device 80 may further include other components as necessary.

Cooling water passage 6011 is formed inside the tuyere 601 and the cooling water flows. Therefore, the tuyere 601 can be prevented from being deteriorated and damaged. The valve 6037 is provided in the inner pipe 6031 of the double pipe 603. The valve 6037 can be adjusted to adjust the amount of hydrocarbon-containing gas A blown into the melt gasifier. On the other hand, the steam inlet 6035 is provided in the outer tube 6035 of the double tube 603. The steam B is supplied through the steam inlet 6035. The oxygen inlet 6013 is connected to the through hole 6015 to supply oxygen (C). As a result, the hydrocarbon-containing gas (A), vapor (B) and oxygen (C) can be blown together at the bottom of the coal filling bed.

In the molten iron manufacturing method according to the present invention, since the steam is blown while preventing the contact between the oxygen and the hydrocarbon-containing gas, it is possible to prevent the melting of the tuyere and the double pipe. In addition, the vapor can be in direct contact with the hydrocarbon-containing gas to reduce the heat load at the end of the tuyere and the end of the double pipe, it is possible to generate a large amount of reducing gas.

It will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the following claims.

Claims (14)

Converting the iron ore into a reducing body while passing through the reduction furnace, Charging a bulk carbonaceous material into a molten gasifier connected to the reduction furnace to form a coal filling layer; Charging the reducing body into a melting gasifier connected to the reducing furnace, and injecting oxygen, steam, and a hydrocarbon-containing gas together in the lower portion of the coal filling layer to prepare molten iron; and Supplying the reducing gas discharged from the molten gasifier to the reduction furnace Including, In the step of producing the molten iron, after the steam is blown while preventing contact between the oxygen and the hydrocarbon-containing gas, the steam reacts with the hydrocarbon-containing gas to produce the reducing gas. In claim 1, In the step of producing the molten iron, the amount of oxygen is more than twice the amount of the hydrocarbon-containing gas manufacturing method. In claim 1, In the step of converting the iron ore into a reducing body, the reduction furnace molten iron manufacturing method is a fluidized bed reduction furnace. In claim 1, In the step of converting the iron ore into a reducing body, the reduction furnace is a molten iron manufacturing method is a packed-bed reduction furnace. delete A reduction furnace for reducing iron ore and converting it into a reducing body, A bulk coal material is charged into the interior to form a coal filling layer, and includes a tuyere for blowing oxygen, steam, and hydrocarbon-containing gas together at the bottom of the coal filling layer, and is connected to the reduction furnace to charge the reducing body. Molten gasification furnace for producing molten iron, and Reduction gas supply pipe for supplying the reducing gas discharged from the melt gasifier to the reduction furnace / RTI > A through hole is formed in the tuyere, and a double tube is inserted into the through hole, and the molten iron manufacturing apparatus blows in the vapor while preventing contact between the oxygen and the hydrocarbon-containing gas. delete In claim 6, The double pipe has an inner tube and an outer tube surrounding the inner tube, and the molten iron manufacturing apparatus for blowing steam between the inner tube and the outer tube. In claim 8, A molten iron manufacturing apparatus for blowing a hydrocarbon-containing gas through the inner tube. In claim 6, The molten iron manufacturing apparatus for blowing oxygen through the through hole outside the double pipe. In claim 6, And an end portion of the tuyere on the melt gasifier side and an end portion of the double pipe on the same line. In claim 6, And the amount of oxygen is at least two times the amount of the hydrocarbon-containing gas. In claim 6, The reduction furnace is a molten iron manufacturing apparatus is a fluidized bed reduction furnace. In claim 6, The reduction furnace is a molten iron manufacturing apparatus is a packed-bed reduction furnace.

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