KR101610286B1 - Manufacturing method of reduced iron and apparatus for Manufacturing the same - Google Patents

Abstract

The method for producing reduced iron according to the present invention comprises the steps of producing a briquettes by mixing a mixture of an iron raw material and a carbonaceous material, carbonizing the raw materials for carbonization, charging the briquettes into a reduction furnace of the reduction machine, To a reducing unit to produce reduced iron, and supplying the exhaust gas generated from the carbonization furnace to the cooling furnace, charging the reduced iron produced by the reducing unit into the cooling furnace, and cooling the reduced iron.
Therefore, according to the embodiment of the present invention, as compared with the conventional case in which a heat source and a reducing gas are separately provided to a reducing furnace, manufacturing cost of the reduced iron can be reduced. In addition, in the present invention, the use of the exhaust gas generated from the carbonization furnace of a general refining facility, without providing a heat source for supplying the reducing furnace and a reducing gas, is used and the cost saving effect is great.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reduced iron production method,

The present invention relates to a reduced iron manufacturing facility and a manufacturing method thereof, and relates to a reduced iron manufacturing method for manufacturing reduced iron using a low-quality raw material and a manufacturing facility therefor.

In general reduction iron production method, reduced iron is produced by mixing iron ore and coal, which acts as a reducing agent, into a compact to produce a carbonaceous material-containing briquettes, and reducing the carbonaceous material-containing briquettes in a reducing machine. However, in the case of the reduction method of the carbonaceous internal briquettes in the reducing unit, the heat transfer rate is slow in the reducing unit, and mass production is limited.

On the other hand, in case of coal, it can be classified into low grade coal, middle grade gypsum and high grade coal according to the constituents or moisture and volatile contents. Low carbon content and high moisture and volatile content are low grade coal. For example, coal of lignite and sub-bituminous coal is low-grade coal (low-grade coal), which has a high content of moisture and volatile matter, low carbon content and low calorific value, compared with mildew and high grade coal. Thus, when low-grade carbon is used as the reducing agent, the reduction rate is low, and the quality of the reduced iron is deteriorated. Therefore, in general, in the production of reduced iron, a medium-quality hue or high-quality carbon is used as a reducing agent.

However, since the high-grade coal and the medium grade gypsum are limited in the amount of the deposits and are expensive compared to the low grade gypsum, there arises a problem that the cost for manufacturing the reduced gypsum increases when high grade coal or medium grade gypsum is used as the reducing agent.

Korean Patent Publication No. 10-2002-0015897

The present invention provides a reduced iron manufacturing method for producing reduced iron using a low-grade raw material and an equipment for manufacturing the reduced iron.

The present invention also provides a reduced iron production method and a manufacturing facility thereof for reducing iron production cost.

A method for manufacturing reduced iron according to the present invention includes the steps of: preparing a briquettes by mixing a mixture of an iron raw material and a carbonaceous material; A process of carbonizing raw materials for carbonization; Charging the briquettes into a reduction furnace of a reduction unit and supplying exhaust gas generated from the carbonization furnace to a reduction unit to produce reduced iron; And supplying the exhaust gas generated from the carbonization furnace to a cooling furnace and charging the reduced iron produced by the reducing unit into a cooling furnace to cool the reduced iron.

And supplying the exhaust gas generated during cooling of the reduced iron to the reducing unit in the cooling furnace.

Wherein the reducing unit includes a burner connected to a reducing furnace and providing a heat source for heating the reducing furnace, wherein the exhaust gas generated in each of the carbonization furnace and the cooling furnace is supplied to the reducing unit, Is supplied to the reducing furnace and the fuel of the burner to heat and maintain the inside of the reducing furnace at the reducing temperature of the briquetting to form a reducing atmosphere.

In the process of cooling the reduced iron in the cooling furnace, the exhaust gas generated from the generator for generating electric power by using the exhaust gas generated in the reducing furnace is supplied to the cooling furnace, And the reduced iron charged into the cooling furnace is cooled by an endothermic reaction between the cooled cooling furnace and the reduced iron and the carbonized furnace exhaust gas.

It is preferable that the carbonaceous raw material carbonized in the carbonization furnace is at least one of coal, waste plastics and waste tires of bituminous coal or lignite series.

The iron raw material may be at least one of iron ore, iron and iron by-products generated in a steel process, and sludge, and the carbonaceous material may be selected from the group consisting of sludge, char generated through carbonization in the carbonization furnace, It is preferable to use one.

In mixing the iron raw material and the carbonaceous material, it is preferable that the carbonaceous material is mixed so that the carbonaceous material is contained in an amount of 5 wt% to 20 wt% in the mixture of the iron raw material and the carbonaceous material.

The apparatus for producing reduced iron according to the present invention comprises a briquetting apparatus for producing a carbonaceous material-containing briquettes by mixing iron raw materials and carbonaceous materials; A carbonization furnace for carbonizing the raw material for carbonization; A reducing unit for producing reduced iron by reducing the briquettes; A cooling furnace for receiving the reduced iron from the reducing unit to cool the reduced iron; A first gas supply line connected to the carbonization furnace and the reducing unit to supply exhaust gas generated from the carbonization furnace to the reducing unit; And a second gas supply line connected to the carbonization furnace and the cooling furnace, for supplying exhaust gas generated from the carbonization furnace to the cooling furnace.

And a third gas supply line connected between the cooling furnace and the reduction unit and supplying the exhaust gas generated during the cooling of the reduction iron to the reducing unit in the cooling furnace.

Wherein the reducing unit includes a burner connected to a reducing furnace to provide a heat source for heating the reducing furnace, the first gas supply line includes a first supply pipe installed to connect the carbonization furnace and the reducing furnace, Wherein the second gas supply line includes a third supply line installed to connect the cooling line and the reduction line, and a fourth supply line connected to the cooling line and the burner, .

And a fourth gas supply line connected to the generator for generating electric power using the exhaust gas generated in the reduction furnace at one end and connected to the cooling furnace at the other end to supply the exhaust gas generated during power generation to the cooling furnace do.

 According to the present invention, at least one of the raw material for producing briquettes and the raw material carbonized in the carbonaceous furnace is used as low-priced low-cost coal (low-grade coal), thereby reducing the cost of raw materials for producing reduced iron.

In addition, by using the exhaust gas generated from the carbonaceous furnace, which is one of the general furnace facilities, and the cooling furnace as the heat source and the reducing gas of the reducing furnace, the reduction rate and the reduction rate of the briquet are improved, Can be prepared. The present invention can reduce the manufacturing cost of the reduced iron as compared with the conventional method in which the heat source and the reducing gas are separately provided to the reducing furnace. In addition, in the present invention, the use of the exhaust gas generated from the carbonization furnace of a general refining facility, without providing a heat source for supplying the reducing furnace and a reducing gas, is used and the cost saving effect is great.

By supplying the carbonized furnace exhaust gas to the cooling furnace for cooling the reduced iron, the reductant of the reduced iron can be prevented from being reoxidized during cooling. Further, the carbonized furnace exhaust gas supplied to the cooling furnace endothermically reacts with the reduced iron to promote the cooling of the reduced iron, thereby improving the cooling rate and the cooling efficiency.

1 is a block diagram of a reduction iron manufacturing facility according to an embodiment of the present invention.
FIG. 2 is a block diagram illustrating a process of supplying exhaust gas generated from a carbonization furnace to a reducing unit and a cooling furnace in an apparatus for manufacturing reduced iron according to an embodiment of the present invention, and supplying the exhaust gas generated in the cooling furnace to a reducing unit. Degree
3 is a graph showing the reduction ratio of briquettes according to the content of briquette carbonaceous material and the atmosphere in the reducing furnace
4 is a graph showing the carbon content in the reduced iron according to the content of the briquette carbonaceous material and the atmosphere in the reducing furnace
5 is a flowchart showing a method of manufacturing reduced iron using a reduced iron manufacturing facility according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be understood, however, that the invention is not limited to the disclosed embodiments, but is capable of other various forms of implementation, and that these embodiments are provided so that this disclosure will be thorough and complete, It is provided to let you know completely.

1 is a block diagram of a reduced iron manufacturing facility according to an embodiment of the present invention. FIG. 2 is a block diagram illustrating a process of supplying exhaust gas generated from a carbonization furnace to a reducing unit and a cooling furnace in an apparatus for manufacturing reduced iron according to an embodiment of the present invention, and supplying the exhaust gas generated in the cooling furnace to a reducing unit. . FIG. 3 is a graph showing the briquetting rate of the briquettes according to the contents of the briquette carbon materials and the atmosphere in the reducing furnace. 4 is a graph showing the content of briquette carbonaceous material and the carbon content in the reduced iron according to the atmosphere in the reducing furnace.

3 and 4, the change in the briquetting rate and the carbon content in the reduced iron according to the content of the briquette carbonaceous material and the atmosphere in the reducing furnace will be described.

1 and 2, a reduced iron manufacturing facility according to an embodiment of the present invention includes a briquetting apparatus 100 for manufacturing a carbonaceous material briquette by mixing an iron raw material and a carbonaceous material, A reducing furnace 200 for producing reduced iron by reducing the produced briquettes, a cooling furnace 700 for cooling the reduced iron produced in the reducing machine 200, a carbide furnace 400 for carbonizing the raw material for carbonization, A first gas supply line 510 connected to the carbonization furnace 400 and the other end connected to the reduction unit 200 to supply the exhaust gas generated in the carbonization furnace 400 to the reduction unit 200, A second gas supply line 520 connected to the cooling channel 700 and connected to the cooling channel 700 to supply the exhaust gas generated in the carbonization furnace 400 to the cooling channel 700, And the other end is connected to the reducer 200 to supply the exhaust gas generated in the cooling furnace 700 to the reducer 200 Include a third gas supply line 530. A fourth gas supply line (not shown) for supplying the exhaust gas generated in the generator 800 to the cooling furnace 700 is connected to the generator 800, which is one end of the generator, and the other end is connected to the cooling furnace 700 540 and the first to third gas supply lines 510, 520 and 530 so that the exhaust gas of the carbonization furnace 400 is supplied to the reducer 200 and the cooling furnace 700, respectively, (Not shown).

The briquetting apparatus 100 produces a briquette-containing briquettes by massively mixing a mixture of an iron raw material and a carbonaceous material. The briquette production apparatus 100 includes a crusher 120 for crushing a carbonaceous material, a first hopper 110a in which the iron raw material is received, a second hopper 110b in which the crushed carbonaceous material is received, a third hopper A mixer 130 for feeding and mixing iron raw materials, carbonaceous materials and binders from the first to third hoppers 110a, 110b and 110c, and a mixer 130 for mixing and mixing iron raw materials, And a molding machine 140 for molding the mixture to produce a carbonaceous material-containing briquettes.

The iron material to be stored in the first hopper 110a may be at least one of iron ore and iron ore by-products (or iron dust) and sludge generated in a steel process, and the iron material to be fed into the mixer 130 may have a minus Minute particle size. In the embodiment of the present invention, iron ore used as a raw material for iron is low-priced low-cost coal (low grade coal) having high moisture and volatile content and low cost, and more specifically, coal of lignite and sub-bituminous coal is used.

The carbonaceous material stored in the second hopper 110b is a reducing agent that induces reduction of briquettes, and contains a material containing carbon (C). Here, the carbonaceous material is at least one of coal, a by-product by-product of high-grade coal, medium-quality gypsum and low-grade carbon, or char which is carbonaceous material produced by the carbonization process in the carbonization furnace 400. The carbonaceous material is crushed by the crusher 120, and it is preferable that the crushed material is crushed to have a particle size of 1 mm or less.

An organic binder such as tar or water glass is stored in the third hopper 110c.

In the mixer 130, the iron material, the carbon material and the binder provided from the first to third hoppers 110a, 110b and 110c are mixed. At this time, a certain amount of iron material, carbon material and binder are supplied to the mixer 130 in each of the hoppers 110a, 110b and 110c, and the mixing ratio is controlled according to the reduced iron to be produced. Preferably, when the mixture containing the iron raw material and the carbonaceous material is 100% by weight, the carbonaceous material is mixed at 5% by weight to 20% by weight.

The molding machine 140 is a molding machine, that is, a twin roll molding machine, although not shown, having a pair of rolls arranged to face each other. Thus, when the mixture is charged between the pair of rolls, the briquettes are produced by extrusion due to the rotation of the pair of rolls. Of course, the molding machine is not limited to the twin roll molding machine described above, and various means capable of molding into briquet can be used.

On the other hand, generally, in manufacturing molten iron, molten iron is used as a source of iron (Fe source), and other additives such as reduced iron and limestone (CaO), magnesium oxide (MgO) and dolomite are melted in a melting furnace do. At this time, fuel for melting the reduced iron is charged in the melting furnace, and coal is used as the fuel. However, since the coal contains predetermined moisture and volatile components, there is a problem in that when the coal as it is charged into the melting furnace without removing the moisture and volatile components, the melting speed and the reduction speed are slowed down due to moisture and volatile matter. Therefore, in general, a carbon furnace 400 for removing moisture and volatile matter of the coal is separately provided before the coal is charged. In the carbon furnace 400, the coal is heated to 600 to 800 ° C, for example, , Water and volatile matter contained in the coal are removed. When coal is carbonized in the carbonization furnace 400 and moisture and volatile components are removed, a carbon as a carbonaceous material is produced. Generally, Char is charged into a melting furnace and used as fuel for melting the reduced iron.

As described above, the carbonization furnace 400 carbonizes a raw material containing carbon (C), that is, a carbonization raw material, and removes moisture and volatile components from the carbonization raw material to produce a carbon (Char) . Although not shown in the carbonization furnace 400, the carbonization furnace 400 includes a hot-air generating furnace 400 for supplying a high-temperature exhaust gas into the carbonization furnace 400, An exhaust gas supply pipe connected to the hot air generating path at one end and connected to the carbonization furnace at the other end to supply a high temperature exhaust gas of the hot air generating path to the carbonizing furnace 400 is connected. Here, the hot air generating path is provided with a burner (not shown), and a separate fuel supply line (not shown) is connected.

In the present invention, the carbonized raw material generated in the carbonization process in the carbonization furnace 400 is supplied to the reduction furnace 210 to reduce the briquettes and supplied to the cooling furnace 700 to cool the reduced iron produced. The carbonization furnace 400 according to the embodiment is a general carbonization furnace installed to supply fuel to a melting furnace in a general furnace, and the first and second gas supply lines 510, 520 are connected to the reducing furnace 210 and the cooling furnace 700.

Further, in the embodiment of the present invention, at least one of coal, waste plastic, or waste tire is used as a carbonization raw material. To this end, a hopper (hereinafter referred to as a fourth hopper 410) for storing the carbonized raw material and supplying it as a carbonization furnace is provided. In addition, low-grade coal such as bituminous coal or lignite coal, which has a high content of moisture and volatile matter and has a low carbon content and low cost, is used as a raw material for carbonization.

The carbonization process in the carbonization furnace 400 will be briefly described below.

And low-grade coal such as carbon black (for example, sub-bituminous coal or lignite-type coal) is charged into the carbonization furnace 400 from the fourth raw hopper 410. Further, the inside of the carbonization furnace 400 is heated to a temperature of, for example, 600 캜 to 800 캜, and more preferably, 700 캜 to form a carbonization atmosphere. To this end, a high-temperature gas is generated using a burner in the hot air generating furnace, and the generated high-temperature gas is supplied to the carbonization furnace 400 through a gas supply pipe, and hydrogen sulfide (H ₂ S) Is supplied to the carbonization furnace (400). As the coal is reacted and carbonized in the carbon furnace 400, a charge (Char) from which moisture and volatile components are removed from the coal is generated. In the present invention, the char generated in the carbonization furnace 400 is used as a binder in the sintering process, a pulverized coal raw material in a blast furnace, a raw material for sintering in a coke making process, or used as a carbonaceous material in the manufacture of a carbonaceous material briquettes . When carbonization of the carbonized raw material containing carbon in the carbonization furnace proceeds, a gas containing any one of oxygen, hydrogen and carbon, more specifically, H ₂ O, CO gas, CHn series gas such as CH ₄ , tar Gas and H ₂ gas, that is, flue gas is a by-product. In other words, H ₂ O, CO gas, and CHn series gas such as CH ₄ , tar gas and H ₂ gas, which are volatile component gases dried and volatilized during the carbonization step of the carbonization material, are produced.

In the present invention, the exhaust gas generated in the carbonization furnace is recovered and supplied to the reduction unit 200 to be used as a heat source and a reducing gas for the heat source and the atmosphere in the reduction unit 200. The exhaust gas is supplied to the cooling unit 700, And is used as a reaction gas for cooling the atmosphere gas and cooling the reaction chamber 700. A first gas supply line 510 is provided to connect the carbonization furnace 400 and the reducer 200 and a second gas supply line 530 is provided to connect the carbonization furnace 400 and the cooling path 700. [ ).

The reducer 200 reduces the briquettes produced in the molding machine 140 to produce reduced iron. The reducing unit 200 includes a reducing furnace 210 having an inner space capable of receiving the briquet and reducing the briquetting therein and a burner 220 installed in the reducing furnace 210 for heating the reducing furnace 210, And a fuel supply pipe (not shown) for supplying fuel to the burner 220.

For the reduction of the briquettes, the reducing furnace 210 must maintain the reducing temperature of the briquettes, and the inside thereof should be formed into a reducing atmosphere. Thus, by burning the fuel using the burner 220, the reducing furnace 210 is heated to the reducing temperature of the briquetting gas and the reducing gas is introduced into the reducing furnace 210.

Conventionally, only fuel separately provided such as LPG and air is used as the fuel to be supplied to the burner 220, but in the present invention, exhaust gas generated when carbonization of the carbonization material in the carbonization furnace 400 may be used. That is, only the flue gas generated from the carbonization furnace 400 may be supplied to the fuel supply pipe as the fuel of the burner 220, or the flue gas generated from the LPG and the air and the carbonization furnace 400 may be supplied together. In addition, a reducing gas is supplied to the inside of the reducing furnace 210 to form a reducing atmosphere. Conventionally, pure CO gas or H ₂ gas is separately provided from the outside and supplied to the reducing furnace 210. However, in the present invention, the flue gas generated during the carbonization of the carbonization material in the carbonization furnace 400, that is, H ₂ O, CO gas, CHn series gas such as CH ₄ , tar gas and H ₂ gas, ), Thereby forming a reducing atmosphere. The exhaust gas to be supplied to the reduction furnace 210 is a flue gas generated from a carbonization furnace heated at 600 to 800 ° C., and thus is in a state of being heated to a high temperature of 600 ° C. to 800 ° C. or lower. Therefore, when the exhaust gas of the carbonaceous furnace 400 is supplied to the reduction furnace 210, the exhaust gas contributes to the heat source for heating or maintaining the reduction furnace 210 at the reduction temperature.

The first gas supply line 510 is connected to the carbonization furnace 400 and the other end is connected to the reduction unit 200. The first gas supply line 510 has an inner space through which the exhaust gas generated from the carbonization furnace 400 can pass, . The first gas supply line 510 is connected to the reducing furnace 210 to supply the exhaust gas to the reducing furnace 210 to form a reducing atmosphere, And a supply pipe (hereinafter referred to as a second supply pipe 510b) connected to the burner 220 to supply the exhaust gas as the fuel of the burner 220. In each of the first and second supply pipes 510a and 510b, A valve (not shown) and a cyclone are installed.

The cooling furnace 700 has a tubular shape having an internal space as a means to cool and receive the reduced iron provided from the reducing furnace 210. The cooling furnace 700 has a structure in which the cooling furnace 700 and the reduced iron are cooled Is supplied. In the present invention, exhaust gas such as CO ₂ , H ₂ O, etc. having a temperature of room temperature or below generated by a generator 800 that generates electricity using the exhaust gas generated from the reduction furnace 210 is recovered, (700) to cool the cooling furnace (700). On the other hand, when the reduced iron is charged into the cooling furnace 700 and cooled, if the oxygen content in the cooling furnace 700 is large, the reduced iron can be reoxidized. In order to prevent this, the inside of the cooling furnace 700 supplies gas into the cooling furnace 700 in order to lower the concentration of oxygen or to prevent the formation of an oxidizing atmosphere. In the present invention, the exhaust gas generated in the carbide furnace 400, H ₂ O, CO gas and CHn series exhaust gas such as CH ₄ , tar gas and H ₂ gas.

As described above, according to the present invention, since the low-temperature exhaust gas such as CO ₂ and H ₂ O generated in the generator is supplied to the cooling path, the cooling path 700 is heated, thereby cooling the reduced iron. In the present invention, the exhaust gas generated in the carbon furnace 400 is supplied into the cooling furnace 700 to prevent the inside of the cooling furnace 700 from becoming oxidizing atmosphere so that the reduced iron is not reoxidized. Also, in the exhaust gas generated from the carbonization furnace 400, H ₂ O, CO, and CHn-based flue gas and tar flue gas respectively undergo a cracking reaction, which is an endothermic reaction with reduced iron, wherein the endothermic reaction greatly contributes to cooling the reduced iron do. That is, in the present invention, in cooling the reduced iron in the cooling furnace 700, the exhaust gas generated from the carbonization furnace 400 is further supplied to prevent the reductant from being reoxidized and to cause the endothermic reaction to reduce the cooling effect of the reduced iron .

The second gas supply line 530 is a pipe having an internal space through which the exhaust gas generated from the carbonization furnace 400 can pass and is connected at one end to the carbonization furnace 400 and at the other end to the cooling path 700 . The second gas supply line 530 may be provided with a cyclone providing a driving force to supply the exhaust gas of the valve and the carbonization furnace 400 to the cooling path 700.

On the other hand, when the exhaust gas generated in the carbon furnace 400 is supplied to the cooling furnace 700 as described above, the exhaust gas of H ₂ O, CO, CHn series and the exhaust gas of the exhaust gas, respectively, ) Reaction occurs, resulting in CO and H ₂ offgases, where CO and H ₂ offgases are reductive gases. In the present invention, the reducing exhaust gas generated in the cooling furnace 700 is supplied to the reducing unit 200 and used as a heat source and a reducing gas. That is, the exhaust gas generated in the cooling furnace 700 is supplied to at least one of the reducing furnace 210 and the burner 220, and the atmospheric gas that forms the reducing atmosphere in the reducing furnace 210, It is used as a heat source to heat or maintain temperature.

The third gas supply line 530 is a pipe having an internal space through which the exhaust gas generated in the cooling path 700 can pass and is connected at one end to the cooling path 700 and at the other end to the reducer 200 . The third gas supply line 530 includes a supply pipe (hereinafter referred to as a third supply pipe 530a) connected to the reducing furnace 210 to directly supply the exhaust gas into the reducing furnace 210, (Hereinafter referred to as a fourth supply pipe 530b) connected to the third and fourth supply pipes 530a and 530b to supply the exhaust gas as fuel for the burner 220, (Not shown) and a cyclone are installed.

As described above, in the present invention, in producing the carbonaceous material-containing briquettes, the carbonaceous material is contained in an amount of 5 wt% to 20 wt%. This is to improve the reduction ratio and improve the carbon content of the reduced iron. Further, the reduction ratio of the briquettes and the carbon content of the reduced iron vary depending on the atmosphere of the reducing furnace 210 for reducing the briquettes.

3 and 4, the change in the briquetting rate and the carbon content in the reduced iron according to the content of the briquette carbonaceous material and the atmosphere in the reducing furnace will be described.

For the experiment, in producing the briquettes, other briquettes with a carbonaceous content of more than 0% by weight and 35% by weight are produced. In reducing the briquettes containing different amounts of carbonaceous materials in the reduction furnace, the atmosphere of the reducing furnace is controlled to be different between the inert gas atmosphere and the reducing gas atmosphere. For example, nitrogen (N ₂ ) gas, which is an inert gas, is supplied to a reduction furnace to reduce briquettes of which the content of carbonaceous material is greater than 0 wt% and 35 wt% in a reducing furnace formed in an inert atmosphere. Nitrogen (N 2) gas, which is an inert gas, and CO 2 gas, which is a reducing gas, are mixed and supplied to the reducing furnace. At this time, CO gas is made to be 30% with respect to the entire mixed gas. By weight, more than 0% by weight and 35% by weight, respectively.

Referring to FIG. 3, when the inert gas and the CO gas as the reducing gas are supplied together, the reduction ratio and the carbon content in the reduced iron are higher than when only the inert gas is supplied to the reducing furnace. This is because the reduction reaction of the briquet proceeds in parallel with the reaction by the carbon material contained in the briquet, that is, the carbon, and the reduction reaction by the reduction gas (that is, the CO gas) which is the external element, As a result, the carbon content in the reduced iron is increased. The residual carbon content in the reduced iron greatly contributes to the reduction reaction of reduced iron and the carburization of Fe in the blast furnace, thereby contributing to the improvement of the reactivity of the reduced iron in the blast furnace and the blast furnace operation efficiency.

5 is a flowchart showing a method of manufacturing reduced iron using a reduced iron manufacturing facility according to an embodiment of the present invention.

Referring to FIG. 5, a method of manufacturing reduced iron according to an embodiment of the present invention includes the steps of preparing iron material and carbon materials, mixing them (S100), forming a mixture of iron material and carbonaceous material, (S200), carbonizing the carbonized raw material containing carbon (S400), reducing the briquettes to produce reduced iron (S300), and cooling the reduced iron (S500).

Hereinafter, with reference to FIG. 1, FIG. 2, and FIG. 5, a reduced iron manufacturing method using reduced iron manufacturing equipment according to an embodiment of the present invention will be described in more detail.

First, prepare the iron raw material as the reducing material and the carbonaceous material as the reducing agent. Here, the iron raw material may be at least one of low iron ore and iron and iron by-products generated in a steel process, and the iron ore preferably has a particle size of 0.1 mm or less. In addition, the carbonaceous material uses at least one of coal and by-products produced in the steel manufacturing process. More preferably, low-cost coal such as bituminous coal or lignite coal is used as the carbonaceous material. The prepared carbonaceous materials are crushed by using the crusher 120, so that the particle size of the carbonaceous material is 1 mm or less. The iron material and the carbon material stored in the first and second hoppers 110a and 110b and the binder stored in the third hopper 110c are charged into the mixer 130 to mix the iron material and the carbonaceous material at step S100. At this time, the carbonaceous material is mixed so as to be 5 wt% to 20 wt% with respect to the entire mixture of the iron raw material and the carbonaceous material. Thereafter, the mixture is charged into the molding machine 140 and made into a carbonaceous material-containing briquettes (S200). In the embodiment, the molding is carried out using a molding machine having a pair of rolls disposed to face each other, that is, a twin roll molding machine. When the mixture is charged between the pair of rolls, the extrusion due to the rotation of the pair of rolls Thereby producing a briquettes containing a carbonaceous material. At this time, in the embodiment, the pressure at the time of molding in the molding machine is adjusted to 3 t / cm ² or more in order to manufacture brittle or reduced iron having high strength. Further, in order to secure the strength of the briquettes, it is necessary to operate the briquette downwardly, and the briquetting pressure of the briquettes is 40 to 80 kgf / p.

As described above, during the production of the carbonaceous material-containing briquettes in the briquetting apparatus, carbonization is underway in the carbonization furnace.

That is, the carbonized material stored in the fourth hopper 410, for example, low-grade coal such as bituminous coal or lignite-based coal is charged into the carbonization furnace 400 and the carbonization furnace 400 is heated at a carbonization temperature of, More specifically, the coal is carbonized by heating to about 700 ° C. For this purpose, in the hot air generating furnace, a high-temperature flue gas is generated by using a burner, and the generated high-temperature flue gas is supplied to the carbonization furnace 400. At this time, a gas containing hydrogen sulfide (H ₂ S) To the carbonization furnace (400). As the coal is reacted and carbonized in the carbon furnace 400, a charge (Char) from which moisture and volatile components are removed from the coal is generated. Char, which is a product generated from the carbonization furnace 400, is used as a raw material for the pulverized coal raw material in the blast furnace, fuel in the coke production process, or used as a carbonaceous material in manufacturing the carbonaceous material briquettes.

When carbonization of the coal proceeds in the carbonization furnace 400, H ₂ O, CO gas, CHn series gas such as CH ₄ , tar gas and H ₂ gas are generated, and these gases are then supplied to the reducing unit 200 And is used as a heat source and a reducing gas for reduction.

The briquettes produced in the briquetting apparatus 100 are charged into the reducing furnace 210, and the reducing furnace 210 manufactures reduced iron through a reduction reaction of the carbonaceous material-containing briquettes (S300). In order to reduce the carbonaceous material briquettes in the reducing furnace 210, the inside of the reducing furnace 210 should be heated to a reducing temperature of, for example, 1000 캜 to 1200 캜 of the carbonaceous internal briquettes to form a reducing atmosphere. To this end, in the present invention, at least one of the exhaust gases generated in each of the carbon furnace 400 and the cooling furnace 700 is supplied to the reducer 200.

First, the exhaust gas generated in the carbon furnace 400 is supplied to the reducing unit 200

In the present invention, the exhaust gas generated in the carbon furnace 400 is supplied to at least one of the reducing furnace 210 and the burner 220 of the reducer 200. The carbonaceous flue gas 400 directly supplied to the reduction furnace 210 forms a reducing atmosphere in the reducing furnace 210. The inside of the reducing furnace 210 is reduced to the reducing temperature Lt; / RTI > The carbonaceous exhaust gas 400 supplied to the fuel supply pipe or the burner 220 is used as fuel for the burner 220.

More specifically, the burner 220 is operated to heat and maintain the reducing furnace 210 at a reduction temperature of the briquette, that is, 1000 ° C to 1200 ° C. That is, when the fuel, such as LPG and air, is supplied to the burner 220 to burn it, the reducing furnace 210 is heated by the burned heat. At this time, in the present invention, a carbonaceous exhaust gas (400) may be used as a raw material for combustion. When the exhaust gas generated in the carbonization furnace 400 is supplied to the burner 220, the gas is burned. As a result, Is heated. The LPG, the air and the exhaust gas of the carbonaceous furnace 400 may be supplied together by the burner 220 or only the carbonaceous exhaust gas may be used in the case of using the exhaust gas of the carbonaceous furnace 400 as the raw material for the burner 220 .

The valve provided in the first supply pipe 510a is opened to operate the cyclone and the exhaust gas generated in the carbon furnace 400 is supplied to the reducing furnace 210 of the reducing unit 200. [ At this time, in the carbonization furnace 400, since the coal is heated by heating to 600 to 800 ° C, a flue gas of a high temperature having a temperature of 600 ° C to 800 ° C or lower is generated in the carbonization furnace 400, The exhaust gas flows through the first supply pipe 510a and is supplied to the reduction furnace 210. [ The high-temperature carbonaceous flue gas 400 supplied to the reduction furnace 210 functions as a heat source, and the inside of the reduction furnace 210 is maintained at the heating or reduction temperature at the reduction temperature by the carbonaceous flue gas. The carbonaceous exhaust gas 400 supplied to the reduction furnace 210 is combusted by the operation of the burner 220 and contributes to heating and maintaining the reduction furnace 210 at the reduction temperature of the briquettes. The exhaust gas of the carbonization furnace 400 includes H ₂ O, CO gas, CHn series gas such as CH ₄ , tar gas and H ₂ gas, and at least a CO gas, a CHn series gas H _{Since the second} gas is a reducing gas, the interior of the reducing furnace 210 is formed into a reducing zone by the carbonaceous exhaust gas 400 supplied through the first supply pipe 510a.

The exhaust gas of the carbonization furnace 400 is supplied to both the reducing furnace 210 and the burner 220 of the reducing unit 200. However, And LPG and air can be supplied to the burner 220 without supplying the flue gas of the carbonization furnace 400 to use as the fuel. Conversely, the exhaust gas of the carbonization furnace 400 can be supplied to the reducing furnace 210, and the exhaust gas of the carbonization furnace 400 can be supplied to the burner 220 as the fuel gas.

When the reducing furnace 210 is heated to 1000 ° C. to 1200 ° C. and the reducing furnace 210 is formed in a reducing atmosphere, the briquettes charged into the reducing furnace 210 are reduced. That is, self-reaction occurs in the iron raw material and the carbonaceous material within the briquettes charged into the reducing furnace 210, that is, inside the carbonaceous material built-in briquettes, and reduced iron is produced therefrom.

On the other hand, for example, when the heat treatment temperature in the reducing furnace 210 is less than 1000 占 폚, the reduction reaction between the iron raw material and the carbonaceous material does not actively occur, so that the reduced iron production is not easy or the reduced iron production rate may be lowered.

During the reduction of briquettes in the reduction furnace 210, the cooling furnace 700 cools and maintains the reduced iron at a temperature below a predetermined temperature for cooling the produced reduced iron. More specifically, the cooling furnace 700 maintains a temperature of at least 1000 캜, which is the temperature of the reducing furnace 210, and maintains a temperature of, for example, 400 캜 to 600 캜 or lower. To this end, when the exhaust gas of low temperature or normal temperature such as CO ₂ and H ₂ O generated in the generator 800 through the fourth gas supply line 540 is supplied to the cooling furnace 700, the cooling temperature of the reduced iron is maintained. Then, the valve provided in the second supply pipe 510b is opened, and the cyclone is operated to supply the exhaust gas generated in the carbonization furnace 400 to the cooling furnace.

After the reduction process is completed in the reduction furnace 210 to produce reduced iron, the reduced iron is charged into the cooling furnace 700. At this time, since the reduced iron is manufactured through the reduction process at a temperature of 1000 ° C to 1200 ° C, the reduced iron is cooled by the cooling furnace 700 maintaining at least the temperature lower than the reduction temperature. Also, the inside of the cooling furnace 700 is kept at a predetermined concentration or less by the supplied carbonized gas, so that reoxidation of the reduced iron during cooling is prevented. Of the carbonized gas supplied to the cooling furnace 700, H ₂ O, CO, CHn series gas and tar gas respectively react with the reduced iron. At this time, a cracking reaction which is an endothermic reaction is caused, The reduced iron is cooled. That is, the exhaust gas of the carbon furnace (400) supplied to the cooling furnace (700) serves to create an atmosphere in the cooling furnace (700) to prevent reoxidation of the reduced iron and to cool the reduced iron. In other words, the reduced iron has a temperature of the cooling furnace 700 itself maintained at a predetermined temperature or lower and a temperature of the exhaust gas of the generator 800. The supplied carbonized offgas, that is, H ₂ O, CO, CHn series gas, By the endothermic reaction.

Therefore, the reduced iron can be cooled without re-oxidation in the cooling furnace 700 by the supplied exhaust gas of the furnace 400, and the cooling efficiency can be improved or the cooling process time can be shortened.

Reduced iron having been cooled down in the cooling furnace 700 may be used as a source of iron (Fe source) in a blast furnace, an electric furnace or a converter, or as a source of iron (Fe source) of a furnace for producing molten iron.

As described above, during the cooling of the reduced iron in the cooling furnace 700, the H ₂ O, CO, and CHn-based gases and tar gases in the exhaust gas of the carbonaceous furnace 400, which are supplied, The reaction takes place and CO and H ₂ gas are produced. Here, the exhaust gas generated in the cooling furnace 700, that is, the CO and H ₂ gas, is a reducing gas. In the present invention, the exhaust gas generated in the cooling furnace is supplied to the reducer 200.

At this time, the exhaust gas of the carbonization furnace 400 is supplied to at least one of the reducing furnace 210 and the burner 220 of the reduction unit 200. The exhaust gas of the cooling furnace 700 directly supplied to the reducing furnace 210 forms a reducing atmosphere in the reducing furnace 210 and is burned by the operation of the burner 220 to heat the reducing furnace 210 to a reducing temperature And as a heat source to maintain. The exhaust gas of the cooling furnace 700 supplied to the burner 220 is used as fuel of the burner 220 for heating the reducing furnace 210. That is, in order to heat the reducing furnace 210 to the reducing temperature, the valve provided in the fourth supply pipe 530b is opened, the cyclone is operated, and the exhaust gas generated in the cooling furnace 700 is supplied to the burner, In the burner, a combustion reaction is performed using the exhaust gas of the carbonized furnace 400, and the reducing furnace 210 is heated accordingly. At this time, LPG and air can be used as the fuel of the burner together with the carbonizer 400 exhaust gas. The valve provided in the third supply pipe 530a is opened to operate the cyclone and the exhaust gas generated in the carbon furnace 400 is supplied to the reducing furnace 210 of the reducing unit 200. [ Since the exhaust gas of the cooling furnace 700 supplied to the reducing furnace 210 is a reducing gas as CO and H ₂ gas, the inside of the reducing furnace 210 becomes a reducing quartz composition by the supplied exhaust gas of the cooling furnace 700.

The exhaust gas of the cooling furnace 700 is supplied to both the reducing furnace 210 and the burner 220 of the reducer 200. However, And LPG and air can be supplied to the burner 220 without supplying the exhaust gas from the cooling furnace 700 and used as fuel. Conversely, the exhaust gas of the cooling furnace 700 can be supplied to the reducing furnace 210, and the exhaust gas of the cooling furnace 700 can be supplied to the burner 220 as the fuel gas.

As described above, according to the present invention, at least one of the raw materials for producing briquettes and the raw materials to be carbonized in the carbonaceous furnace is used as the low-cost low-cost carbon (low-grade coal), thereby reducing the raw material cost for producing reduced iron.

The exhaust gas generated in the carbonization furnace 400 and the exhaust gas generated in the cooling furnace 700 can be used as a heat source and a reducing gas for the reduction furnace 210 to reduce the brittle reduction rate and reduction rate And thus reduced iron having a high carbon content can be produced.

Then, by supplying the exhaust gas of the furnace 400 to the cooling furnace 700 for cooling the reduced iron, the reductant of the reduced iron can be prevented from being reoxidized during cooling. Further, when the exhaust gas of the carbonaceous furnace 400 is supplied to the cooling furnace 700 for cooling the reduced iron, the cooling is promoted by the endothermic reaction between the exhaust gas of the carbonaceous furnace 400 and the reduced iron, thereby improving the cooling rate and cooling efficiency.

The exhaust gas generated from the carbonization furnace 400, which is one of the general equipment for the steelmaking, is used as a heat source and reducing gas for the reduction furnace 210. Accordingly, the present invention can reduce the manufacturing cost of the reduced iron as compared with the conventional case in which a heat source and a reducing gas are separately provided to the reducing furnace 210. In addition, in the present invention, since the exhaust gas generated from the carbonization furnace of a general refining facility is recovered and used without providing a heat source for supplying the reducing furnace 210 and a reducing gas, cost reduction is significant.

210: Reduction furnace 220: Burner
400: Carbon furnace 700: Cooling furnace

Claims (11)

A process for producing a briquettes by molding a mixture of an iron raw material and a carbonaceous material;
A carbonization step of charging a raw material for carbonization into a carbonization furnace to remove water and volatile components contained in the carbonization raw material to produce a carbonaceous material;
Charging the briquettes into a reduction furnace of a reduction unit and supplying exhaust gas generated in the carbonization process of the carbonization furnace to a reduction unit to produce reduced iron; And
Supplying the exhaust gas generated in the carbonization process of the carbonization furnace to the cooling furnace, charging the reduced iron produced in the reducing unit into the cooling furnace, and cooling the reduced iron;
≪ / RTI > The method according to claim 1,
And supplying the exhaust gas generated during cooling of the reduced iron to the reducing unit in the cooling furnace. The method of claim 2,
Wherein the reducing unit is connected to a reducing furnace and includes a burner for providing a heat source for heating the reducing furnace,
In supplying the exhaust gas generated in each of the carbonization furnace and the cooling furnace to the reducing unit,
A reducing iron manufacturing method in which exhaust gas generated in each of the carbonization furnace and the cooling furnace is supplied to one of the reducing furnace and the fuel of the burner to heat and maintain the inside of the reducing furnace at the reduction temperature of the briquetting, . The method of claim 2,
In the process of cooling the reduced iron in the cooling furnace,
The exhaust gas generated from the power generator using the exhaust gas generated in the reducing furnace is supplied to the cooling furnace to lower the temperature of the carbonization furnace exhaust gas supplied to the cooling furnace,
Wherein the reduced iron charged into the cooling furnace is cooled by an endothermic reaction between the cooled cooling furnace and the reduced iron and the carbonized furnace exhaust gas. The method according to any one of claims 1 to 4,
Wherein the raw material for carbonization which is carbonized by the carbonization furnace is at least one of coal, waste plastics and waste tires of bituminous coal or lignite series. The method according to any one of claims 1 to 4,
The iron raw material may be at least one selected from the group consisting of iron ore, iron and iron by-products generated in a steel process, and sludge,
Wherein the carbonaceous material is selected from the group consisting of coal, char produced through carbonization in the carbonization furnace, and iron oxide dust generated in a steel manufacturing process.
The method according to any one of claims 1 to 4,
Wherein the mixture of the iron source and the carbonaceous material is mixed such that the carbonaceous material is contained in the mixture of the iron source and the carbonaceous material so that the carbonaceous material is contained in an amount of 5 to 20 wt%. A briquetting device for producing a carbonaceous material-containing briquettes by mixing iron raw materials and carbonaceous materials;
A carbonization furnace for removing water and volatile components contained in the raw material for carbonization and producing a carbonaceous material;
A reducing unit for producing reduced iron by reducing the briquettes;
A cooling furnace for receiving the reduced iron from the reducing unit to cool the reduced iron;
A first gas supply line connected to the carbonization furnace and a reducing unit, for supplying exhaust gas generated in the carbonization process of the carbonization furnace to the reducing unit; And
A second gas supply line connected to the carbonization furnace and the cooling furnace, for supplying exhaust gas generated in the carbonization process of the carbonization furnace to the cooling furnace;
/ RTI >
Wherein the first gas supply line includes a first supply pipe installed to connect the carbonization furnace and the reduction furnace, and a second supply pipe connected to the carbonization furnace and the burner. The method of claim 8,
And a third gas supply line provided so as to connect between the cooling furnace and the reducing unit and supplying the exhaust gas generated during the cooling of the reduced iron in the cooling furnace to the reducing unit. The method of claim 9,
Wherein the reducing unit is connected to a reducing furnace and includes a burner for providing a heat source for heating the reducing furnace,
The second gas supply line includes a third supply pipe installed to connect the cooling furnace and the reduction furnace, and a fourth supply pipe installed to connect the cooling furnace and the burner. The method according to any one of claims 8 to 10,
And a fourth gas supply line connected to the generator for generating electric power using the exhaust gas generated in the reduction furnace at one end and connected to the cooling furnace at the other end to supply the exhaust gas generated during power generation to the cooling furnace .

Images