Title of Invention	“TUYERE ASSEMBLY”
Abstract	A tuyere assembly that is capable of improving the combustion rate of an auxiliary fuel is provided. The tuyere assembly that is installed at a melter-gasifier for forming melted iron includes a tuyere where a gas passage used for injecting an oxygen-containing gas into the melter-gasifier and a pair of fuel injection lines spaced apart from each other. The injection lines are spaced apart from the gas passage to pass through the tuyere. The injection lines inject an auxiliary fuel into the melter-gasifier.

Title of Invention

“TUYERE ASSEMBLY”

Abstract

A tuyere assembly that is capable of improving the combustion rate of an auxiliary fuel is provided. The tuyere assembly that is installed at a melter-gasifier for forming melted iron includes a tuyere where a gas passage used for injecting an oxygen-containing gas into the melter-gasifier and a pair of fuel injection lines spaced apart from each other. The injection lines are spaced apart from the gas passage to pass through the tuyere. The injection lines inject an auxiliary fuel into the melter-gasifier.

Full Text	Technical Field This application claims priority to and the benefit of Korean Patent Application No. 2007-0135976 filed on December 24, 2007 in the Korean Intellectual Property Office, the entire content of which is incorporated herein by reference. The present invention relates to a tuyere used for forming molten iron. More particularly, the present invention relates to a tuyere that is capable of effectively injecting auxiliary fuel. Background Art Recently, a smelting reduction method that is capable of replacing the conventional blast furnace method has been developed. In the smelting reduction method, raw coal is directly used as a fuel and a reducing agent, and iron ore is directly used as an iron source. The iron ore is reduced in the reduction reactor and molten iron is formed in the melter-gasifier. A tuyere is formed at a side face of the melter-gasifier. Oxygen is injected into the melter-gasifier through the tuyere, and the oxygen may burn a char bed formed in the melter-gasifier. Thus, melted iron is manufactured by melting the iron ore charged in the melter-gasifier by using the heat of combustion. DISCLOSURE Technical Problem A tuyere assembly that is capable of improving the combustion rate of auxiliary fuel by injecting auxiliary fuel through a pair of fuel injection lines is provided. Technical Solution In accordance with embodiments of the present invention, a tuyere assembly installed at a melter-gasifier for forming melted iron includes a tuyere where a gas passage used for injecting an oxygen-containing gas into the inside of the melter-gasifier and a pair of fuel injection lines spaced apart from each other. The injection lines are spaced apart from the gas passage to pass through the tuyere. The injection lines inject auxiliary fuel into the melter-gasifier. The tuyere assembly may further include a fuel supplying line providing the auxiliary fuel to the pair of fuel injection lines. The pair of fuel injection lines may be provided with the auxiliary fuel from the fuel supplying line. The auxiliary fuel may be provided from the fuel supplying line in a first direction, the auxiliary fuel provided in the first direction may be diverged in a second direction intersecting the first direction, and the auxiliary fuel may be injected to the melter-gasifier through the pair of fuel injection lines in a third direction intersecting the second direction. The first direction may be substantially the same as the second direction, and the first direction may be substantially perpendicular to the second direction. The amounts of auxiliary fuel respectively diverged in the second direction may be substantially the same as one another. The tuyere assembly may further include a diverged line connecting the fuel supplying line to the pair of fuel injection lines to diverge the auxiliary fuel provided through the fuel supplying line into fuel injection lines, respectively. The diverged line may include a first diverged portion connected to the fuel supplying line and extending in a first direction, and at least one second diverged portion connected to the first diverged portion and extending in a second direction intersecting the first direction to be connected to each of the fuel injection lines. The second diverged line and the fuel injection lines may be connected to each other, and the second diverged line intersects the fuel injection lines. The fuel injection lines may be bent. The fuel supplying line may extend in the first direction. The at least one second diverged portion may include the pair of second diverged portions, and each of the second diverged portions are connected to both sides of the first diverged portion. An average cross-section of the first diverged portion formed by cutting the first diverged portion in the second direction may be larger than a cross-section of the fuel supplying line formed by cutting the fuel supplying line in the second direction. An average cross-section of the second diverged portion formed by cutting the second diverged portion in the first direction may be substantially larger than a cross-section of the fuel injection line formed by cutting the fuel injection line in the second direction. An average cross-section of the first diverged portion formed by cutting the first diverged portion in the first direction may be no more than an average cross- section of the second diverged portion formed by cutting the second diverged portion in the first direction. The pair of fuel injection lines may include first end portions where auxiliary fuel contacts an inner portion of the melter-gasifier. The gas passage may include a second end portion where the oxygen-containing gas contacts the inner portion of the melter-gasifier. Imaginary lines connecting the first and second end portions may form a triangle, and the triangle may substantially be an isosceles triangle. The second end portion may be located on a vertex portion of the isosceles triangle. The auxiliary fuel may be a coal dust or a hydrocarbon-containing gas. A direction in which the pair of the fuel injection lines extends may form an acute angle with a direction in which the gas passage extends, and the acute angle may be about 10° to about 40°. The auxiliary fuel and the oxygen-containing gas may be mixed together at a position spaced apart from a front end of the tuyere. Advantageous Effects An auxiliary fuel is injected into a melter-gasifier through a fuel supplying line so that the combustion rate of an auxiliary fuel may be improved. DESCRIPTION OF DRAWINGS FIG. 1 is a perspective view schematically illustrating a tuyere assembly 100 in accordance with a first embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1. FIG. 3 schematically illustrates a cross-sectional structure of the tuyere assembly 200 in accordance with a second embodiment of the present invention. FIG. 4 schematically illustrates a cross-sectional structure of a tuyere assembly 300 in accordance with a third embodiment of the present invention. FIG. 5 schematically illustrates an operation state of the tuyere assembly 100 in accordance with the first embodiment of the present invention. FIG. 6 schematically illustrates a melter-gasifier 500 where the tuyere assembly 100 in accordance with the first embodiment of the present invention is installed. BEST MODE The present invention will be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are illustrated. The invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. It will be understood that when an element or layer is referred to as being "on," "connected to," and/or "coupled to" another element or layer, the element or layer may be directly on, connected, and/ or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on," "directly connected to," and/ or "directly coupled to" another element or layer, no intervening elements or layers are present. It will also be understood that, although the terms "first," "second," etc., may be used herein to describe various elements, components, regions, layers, and/ or sections, these elements, components, regions, layers and/ or sections should not be limited by these terms. Rather, these terms are used merely as a convenience to distinguish one element, component, region, layer, and/or section from another element, component, region, layer, and/ or section. For example, a first element, component, region, layer, and/ or section could be termed a second element, component, region, layer, and/ or section without departing from the teachings of the present invention. Spatially relative terms, such as "beneath," "below," "lower," "above," "upper," and the like, may be used to describe an element and/or feature's relationship to another element(s) and/or feature(s) as, for example, illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use and/ or operation in addition to the orientation depicted in the figures. For example, when the device in the figures is turned over, elements described as below and/ or beneath other elements or features would then be oriented above the other elements or features. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein are to be interpreted accordingly. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit of the invention. As used herein, the singular terms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "includes" and "including" specify the presence of stated features, integers, steps, operations, elements, and/ or components, but do not preclude the presence and/ or addition of one or more other features, integers, steps, operations, elements, components, and/ or groups thereof. As used herein, the expressions "at least one," "one or more," and "and/ or" are open-ended expressions that are both conjunctive and disjunctive in operation. For example, each of the expressions "at least one of A, B, and Q1" "at least one of A, B, or C," "one or more of A, B, and Q1" "one or more of A, B, or Q1" and "A, B, and/ or C" includes the following meanings: A alone; B alone; C alone; both A and B together; both A and C together; both B and C together; and all three of A, B, and C together. Further, these expressions are open-ended, unless expressly designated to the contrary by their combination with the term "consisting of." For example, the expression "at least one of A, B, and C" may also include a fourth member, whereas the expression "at least one selected from the group consisting of A, B, and C" does not. As used herein, the expression "or" is not an "exclusive or" unless it is used in conjunction with the phrase "either." For example, the expression "A, B, or C" includes A alone; B alone; C alone; both A and B together; both A and C together; both B and C together; and all three of A, B, and, C together, whereas the expression "either A, B, or C" means one of A alone, B alone, and C alone, and does not mean any of both A and B together; both A and C together; both B and C together; and all three of A, B, and C together. Unless otherwise defined, all terms (including technical and scientific terms) used herein may have the same meaning as what is commonly understood by one of ordinary skill in the art. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized and/ or overly formal sense unless expressly so defined herein. Embodiments of the present invention may be described with reference to cross-sectional illustrations, which are schematic illustrations of idealized embodiments of the present invention. As such, variations from the shapes of the illustrations, as a result, for example, of manufacturing techniques and/ or tolerances, are to be expected. Thus, embodiments of the present invention should not be construed as limited to the particular shapes of regions illustrated herein, but are to include deviations in shapes that result from, e.g., manufacturing. For example, a region illustrated as a rectangle may have rounded or curved features. Thus, the regions illustrated in the figures are schematic in nature and are not intended to limit the scope of the present invention. Like reference numerals refer to like elements throughout. FIG. 1 is a perspective view schematically illustrating a tuyere assembly 100 in accordance with a first embodiment of the present invention. FIG. 1 illustrates a structure of the tuyere assembly 100 from a viewpoint of a melter-gasifier. As illustrated in FIG. 1, the structure of the tuyere assembly 100 is an example, and the present invention is not limited by the structure. As a result, the structure of the tuyere assembly 100 may be varied. As illustrated in FIG. 1, first end portions 20a and second end portions 1011 are formed at a front end portion 105 of the tuyere 10. The pair of fuel injection lines 20 includes first end portions 201. A gas passage 101 includes the second end portion 1011, and the gas passage 101 is connected to a gas supplying line 60 to provide an oxygen-containing gas. In the first end portion 20a, an auxiliary fuel is provided from the pair of fuel injection lines 20 to contact an inside of the melter-gasifier. In the second end portion 1011, the oxygen-containing gas is provided from the gas passage 101 to contact the inside of the melter-gasifier. Referring to a dotted line in FIG. 1, if the first end portions 201 and the second end portions 1011 are connected to one another, a triangle is formed. In addition, the first end portions 201 are located such that a distance between the first end portion 201 and the second end portion 1011 is uniformly maintained. Thus, the triangle may be an isosceles triangle because the distance between the first end portion 201 and the second end portion 1011 is uniformly maintained. The second end portion 1011 is located at a vertex of the isosceles triangle. Hereinafter, a cross-section of the tuyere assembly 100 is explained with reference to FIG. 2. FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1. The cross-sectional view in FIG. 2 is merely an example, so that the present invention is not limited in FIG. 2. As illustrated in FIG. 2, the tuyere assembly 100 includes a tuyere 10 and a pair of fuel injection lines 20. The pair of the fuel injection lines 20 may be inserted in the tuyere 10. Further, the tuyere assembly 100 may include a fuel supplying line 30, a diverged line 40, and a gas supplying line 60. The gas supplying line 60 providing the oxygen-containing gas may pass below the fuel supplying line 30. As illustrated in FIG. 2, a gas passage 101 is formed at a central portion of the tuyere 10. To manufacture melted iron in the melter-gasifier 500, an oxygen-containing gas is injected to the inside of the melter-gasifier 500 through the gas passage 101. Here, the oxygen-containing gas includes an oxygen gas, a gas including an oxygen, etc. Thus, a hot wind including oxygen may be injected through the gas passage 101 besides the oxygen gas. As illustrated in FIG. 2, a first cooling passage 107 and a second cooling passage 109 are formed inside the tuyere 10. The first cooling passage 107 and the second cooling passage 109 are isolated from each other. Cooling water flowing along the second cooling passage 109 may cool a body of the tuyere 10, and cooling water flowing along the first cooling passage 107 may cool a front end portion of the tuyere 10. The front end portion 105 of the tuyere 10 is located in the melter- gasifier 500 so that the front end portion 105 of the tuyere 10 may be exposed to a relatively high temperature. Thus, the front end portion 106 of the tuyere 10 may be melted to break the cooling passage. If the cooling passage in the tuyere 10 is integrally formed, it is difficult to cool the tuyere 10 when the front end portion of the tuyere 10 is broken. Thus, the usage of the tuyere 10 may be stopped. However, as illustrated in FIG. 2, the first cooling passage 107 and the second cooling passage 109 in the tuyere 10 are isolated. The second cooling passage 109 may still operate even though the first cooling passage 107 is broken when the front end portion of the tuyere 10 is exposed to the relatively high temperature. This is because the second cooling passage 109 is isolated from the first cooling passage 107. A cooling of the tuyere 10 is well known to a person skilled in the art so a detailed explanation is omitted. A pair of fuel injection lines 20 are spaced apart from the gas passage 101. If the pair of fuel injection lines 20 meets the gas passage 101 in the tuyere 10, the auxiliary fuel provided through the pair of fuel injection lines 20 may react with the oxygen-containing gas provided through the gas passage 101. Thus, the tuyere 10 may be melted by the above reaction so that the tuyere 10 may be broken. As a result, the pair of fuel injection lines 20 is spaced apart from the gas passage 101. As illustrated in FIG. 2, the pair of fuel injection lines 20 may pass through the tuyere 10. The auxiliary fuel is provided to the inside of the melter-gasifier 500 through the pair of fuel injection lines 20. Here, as an example, the auxiliary fuel may be coal dust or a hydrocarbon-containing gas. The dust coal includes carbon and has a diameter below about 3mm. Examples of the hydrocarbon-containing gas may include liquid natural gas (LNG), liquid propane gas (LPG), etc. The auxiliary fuel is provided into the melter-gasifier 500 to increase heat of combustion. Thus, the amount of coal provided to an upper portion of the melter-gasifier 500 may be reduced. In addition, the auxiliary fuel may generate an amount of reduction gas so that iron ore may be effectively reduced. Furthermore, the coal provided to the upper portion of the melter- gasifier 500 may be burned before the core reaches a lower portion of the melter-gasifier 500. Thus, the lower portion of the melter-gasifier 500 may be in a state that is unsuitable for manufacturing the melted iron. As a result, the auxiliary fuel may be provided to the lower portion of the melter- gasifier 500 to improve the state of the lower portion of the melter-gasifier 500. As illustrated in FIG. 2, the pair of fuel injection lines 20 may be spaced apart from each other to inject the auxiliary fuel into the melter- gasifier 500. Thus, the auxiliary fuel is properly separated and then provided into the melter-gasifier 500 to increase the combustion rate of the auxiliary fuel. In accordance with the first embodiment to the present invention, the pair of fuel injection lines 20 are used instead of one fuel injection line to provide the inside of the melter-gasifier 500 with the auxiliary fuel. If one fuel injection line is used, one amount of the auxiliary fuel is provided into the melter-gasifier 500 at a time. Thus, an oxygen-containing gas is required to satisfy a relatively large combustion rate. Thus, it is difficult to burn an amount of fine coal. On the other hand, if the pair of fuel injection lines 20 are used as illustrated in the first embodiment, the auxiliary fuel is uniformly dispersed into the fuel injection line 20 and then provided into the melter- gasifier 500. Thus, the oxygen-containing gas may burn a relatively small amount of auxiliary fuel so that the oxygen-containing gas is required to satisfy a relatively small combustion rate. As a result, the auxiliary fuel may be effectively burned by the oxygen-containing gas. Consequently, the melter-gasifier 500 may be operated more effectively. At least three fuel injection lines may be used. If three injection lines are used, three injection lines are required to be inserted into the tuyere. Thus, a structure of the tuyere 10 may become relatively complex. For example, it is difficult to form a cooling passage for cooling the tuyere 10 such that the cooling passage avoids three fuel injection lines. Thus, a cost for designing the tuyere 10 may increase. In addition, if three fuel injection lines are used, the combustion rate of the fine coal may not be larger than that in a case where the pair of fuel injection lines is used. Thus, it is appropriate to use the pair of the fuel injection lines. Each of the fuel injection lines 20 is provided with the auxiliary fuel from the fuel supplying line 30. The auxiliary fuel is provided to the fuel supplying line 30 and then diverged in the diverged line 40. Thereafter, the auxiliary fuel is provided to the fuel injection lines 20. A flange 207 and a valve 209 are installed at the fuel injection line 20. The auxiliary fuel flowing through the fuel injection line 20 may be blocked by the valve 209. The diverged line 40 may divide the auxiliary fuel provided from the fuel supplying line 30 into the fuel injection line 20. The diverged line 40 may be connected to the fuel supplying line 30 and the pair of fuel injection lines 20 by flanges 207 and 309. The diverged line 40 includes a first diverged portion 401 and a second diverged portion 403. In addition, the diverged portion 40 includes three chambers 4011 and 4013. The first diverged portion 401 is connected to the fuel supplying line 30. The first diverged portion 401 extends in an x-direction. The pair of second diverged lines 403 is connected to the first diverged portion 401. The second diverged lines 403 are connected to both side portions of the first diverged portion 401, respectively. The second diverged lines 403 are connected such that they intersect the fuel injection line 20. The second diverged portions 403 extend in ±y-axis directions, respectively. As illustrated in FIG. 2, the diverged portion 40 has a "T" shape. The auxiliary fuel may sequentially pass through the fuel supplying line 30, the diverged line 40, and the pair of the fuel injection lines 20 to be injected into the melter-gasifier 500. Hereinafter, a direction in which the auxiliary fuel passing through the tuyere assembly 100 is transferred is described in more detail with reference to FIG. 2. As illustrated in FIG. 2, the auxiliary fuel is provided from the fuel supplying line 30 in a first direction (i.e., +x-axis direction). Thus, the fuel supplying line 30 extends in the first direction. The auxiliary fuel passes through the diverged line 40 so that the auxiliary fuel may be diverged in a second direction (i.e., +y-axis direction and -y-axis direction). The auxiliary fuel is then provided from the diverged line 40 toward the fuel injection line 20 in a third direction. The third direction may form an acute angle with a direction in which the gas passage 101 extends. Thus, the auxiliary fuel provided from the fuel injection line 20 may be effectively mixed with the oxygen-containing gas provided from the gas passage 101. The first direction and the second direction may be perpendicular to each other. As described above, a proceeding direction of the auxiliary fuel may be largely changed when the auxiliary fuel passes through the diverged line 40. However, the auxiliary fuel may not flow backward or stop. This is because a space where the auxiliary fuel is received is maximized by using three chambers 4011 and 4013. Furthermore, an inner diameter may decrease from the chamber 4013 to the fuel injection line 20 so that a velocity of the auxiliary fuel may be increased. Thus, the auxiliary fuel may be sprayed toward the melter-gasifier 500. The amounts of the auxiliary fuels diverged in the second direction, respectively, may be substantially the same. Thus, the auxiliary fuels may be effectively burned in the melter-gasifier 500. This is illustrated in more detail with reference to a structure of the diverged line 40 in FIG. 2. As illustrated in FIG. 2, a cross-section S401 is a cross-section of the first diverged portion 401 taken in the y-axis direction. Here, an average cross-section is an average of a sum of the cross-section S401 obtained by cutting the first diverged portion 401 in the y-axis direction. In addition, a cross-section S403 is a cross-section of the second diverged portion 403 taken in the x-axis direction. Here, an average cross-section is an average of a sum of the cross-section S403 obtained by cutting the second diverged portion 403 in the x-axis direction. A cross-section S30 of the fuel supplying line 30 is a cross-section obtained by cutting the fuel supplying line 30 in the y-axis direction. In addition, a cross-section S20 of the fuel injection line 20 is a cross-section obtained by cutting the fuel injection line 20 in the y-axis direction. The average cross-section of the first diverged portion 401 is relatively larger than the cross-section S30 of the fuel supplying line 30. That is, an inner diameter of the first diverged portion 401 is large because the first diverged portion 401 includes the chamber 4011. Thus, the auxiliary fuel is effectively supplied from the fuel supplying line 30 to the diverged line 40. In addition, the average cross-section of the second diverged portion 403 is larger than the cross-section S20 of the fuel injection line 20. That is, an inner diameter of the second diverged portion 403 is large because the second diverged portion 403 includes the chamber 4031. Thus, the auxiliary fuel is rapidly supplied from the second diverged portion 403 to the fuel injection line 20. As a result, the combustion rate of the auxiliary fuel may be improved in the melter-gasifier 500. Furthermore, the average cross-section of the first diverged portion 401 is no less than the average cross-section of the second diverged portion 403. Thus, the auxiliary fuel may be rapidly supplied from the first diverged portion 401 toward the second diverged portion 403 because the average cross-section of the first diverged portion 401 is no more than the average cross-section of the second diverged portion 403. As a result, flow velocity of the auxiliary fuel may not be largely reduced even though the proceeding direction of the auxiliary fuel is changed when the auxiliary fuel is supplied from the first diverged portion 401 to the second diverged portion 403. FIG. 3 schematically illustrates a cross-sectional structure of the tuyere assembly 200 in accordance with the second embodiment of the present invention. The structure of the tuyere assembly 200 is substantially the same as the structure of the tuyere assembly 100 in FIG. 2 except for a fuel injection line 22. Thus, the same reference numerals will be used to refer to the same or like parts and further explanation will be omitted. As illustrated in FIG. 3, the fuel injection line 22 is bent. The fuel injection line 22 is connected to the diverged line 40 and then bent to be inserted into the tuyere 10. Here, the fuel injection line 22 is connected to the second diverged line 403 in a direction (i.e., the x-axis direction) perpendicularly intersecting a direction (i.e., the y-axis direction) in which the second diverged line 403 extends. Thus, a connection between the fuel injection line 22 and the second diverged line 403 may be relatively rigid. As illustrated in FIG. 3, the fuel injection line 22 is bent in a direction becoming close to the gas passage 101 so that the auxiliary fuel sprayed from the fuel injection line 22 may be effectively mixed with the oxygen- containing gas sprayed from the gas passage 101. The combustion rate of the auxiliary fuel may be improved because the auxiliary fuel is effectively mixed with the oxygen-containing gas. FIG. 4 schematically illustrates a cross-sectional structure of a tuyere assembly 300 in accordance with a third embodiment of the present invention. The cross-sectional structure of the tuyere assembly 300 in FIG. 4 is substantially similar to the cross-sectional structure of the tuyere assembly 200 in FIG. 3. Thus, the same reference numerals will be used to refer to the same or like parts and further explanation will be omitted. As illustrated in FIG. 4, the tuyere assembly 300 may be manufactured by using a diverged line 42 having a "Y" shape. The diverged line 42 may be combined with a fuel injecting line 30 by a flange 309, and may be combined with a fuel injection line 20 by a flange 207. Flow velocity of the auxiliary fuel provided through the fuel injecting line 30 may not be largely reduced because the diverged line 42 has the "Y" shape. The auxiliary fuel may be provided through the fuel injection line 20 such that the flow velocity of the auxiliary fuel may not be largely reduced. FIG. 5 schematically illustrates an operation state of the tuyere assembly 100 in accordance with the first embodiment of the present invention. As illustrated in FIG. 5, a char bed formed from coal or coke is located at a front portion of the tuyere 10. Here, if the oxygen-containing gas is injected through the gas passage 101, a reduction gas may be generated in forming a raceway at the char bed. In addition, if the auxiliary fuel is injected through the pair of fuel injection lines 20, the auxiliary fuel is directly injected to the raceway so that a reduction gas may be additionally generated. Thus, the amount of reduction gas generated in the melter- gasifier 500 may be maximized and the amount of coal provided to the melter-gasifier 500 may be minimized. Here, a direction in which the pair of the fuel injection lines 20 extends may form an acute angle (?) with a direction in which the gas passage 101 extends. Thus, an injection direction of the auxiliary fuel injected through the pair of the fuel injection lines 20 may form an acute angle (?) with a central line (C) of the tuyere 10. The acute angle (?) may be about 10° to about 40°. If the acute angle (?) is less than about 10°, an auxiliary fuel injected from the fuel injection line 20 may not effectively meet an oxygen-containing gas injected from the gas passage 101. Thus, an ignition of the auxiliary fuel may be delayed. If the acute angle ? is larger than about 40°, the auxiliary fuel and the oxygen-containing gas may meet at front of a front portion 105 of the tuyere 10 so that the ignition may be achieved. Thus, the front end portion 105 of the tuyere may be melted and then damaged. As a result, the acute angle (?) may be managed in a range of about 10° to about 40° FIG. 6 schematically illustrates a melter-gasifier 500 where the tuyere assembly 100 in accordance with the first embodiment of the present invention is installed. Iron ore and coal are charged from an upper portion of the melter- gasifier 500 and then discharged after melted iron is manufactured in the melter-gasifier 500. Here, the iron ore may be charged as reduced iron, and the coal may be charged in the shape of briquettes that may be charged into the melter-gasifier 500 to form a char bed (see FIG. 5) and produce a reduction gas that is to be exhausted outward. The char bed may be burned by the oxygen-containing gas charged through the tuyere assembly 100 to produce heat of combustion. The reduced iron may be melted by the heat of combustion so that the melted iron may be manufactured. The reduction gas exhausted from the melter-gasifier 500 may be provided into the fluidized-bed reduction furnace or the packed-bed reduction furnace so that the reduction gas may reduce the iron ore charged to the fluidized-bed reduction furnace or the packed-bed reduction furnace. As a result, the reduced iron may be manufactured. In accordance with the first embodiment of the present invention, the oxygen-containing gas and auxiliary fuel may be charged through the tuyere assembly 100 so that the heat of combustion in the melter-gasifier 500 may increase. As a result, the amount of briquettes charged from the upper portion of the melter-gasifier 500 may be reduced. Here, the auxiliary fuel may be injected to the inside of the melter-gasifier 500 through the pair of fuel injection lines. Thus, a combustibility of the auxiliary fuel may be improved. Example Fine coal was injected to the melter-gasifier as an auxiliary fuel by using a tuyere assembly having a structure as in FIG. 1. The fine coal was injected to the melter-gasifier through the tuyere assembly by using the pair of fuel injection lines. In addition, pure oxygen was provided to the melter- gasifier through a gas passage of the tuyere assembly. The amount of fine coal injected through the fuel supplying line was about 250kg/ t-p, and the amount of fine coal injected through each diverged fuel injection lines was about 125kg/ t-p. Combustibility of the fine coal was measured at the front of the tuyere. The combustibility of the fine coal was about 95%. Comparative Example Contrary to the example, fine coal was injected to a melter-gasifier by using a tuyere assembly including only one fuel injection line. The fine coal was injected to the melter-gasifier through the fuel injection line. In addition, pure oxygen was injected to the melter-gasifier through a gas passage of the tuyere assembly. The amount of fine coal injected through the fuel injection line was about 150kg/t-p. Combustibility of the fine coal was measured at the front of the tuyere. The combustibility of the fine coal was about 75%. As described in the example and comparative example, the combustibility of the fine coal in the example was about 20% greater than that in the comparative example. Thus, when the pair of fuel injection lines are used, the combustion rate of the fine coal injected to the melter-gasifier through the tuyere may be improved compared with the case where one fuel injection line is used. This is because the oxygen gas may not fully burn the fine coal when a large amount of fine coal is charged into the melter-gasifier at a time, because the oxygen-containing gas is required to burn the fine coal. That is, a large combustion burden is applied to the oxygen-containing gas. On the other hand, when the fine coal is injected through the pair of fuel injection lines, a small amount of the fine coal is dispersed and then injected to the melter-gasifier. Thus, a large amount of combustion burden may not be applied to the oxygen-containing gas. As a result, the oxygen gas may fully burn the fine coal. The foregoing is illustrative of the present invention and is not to be construed as limiting thereof. Although a few embodiments of this invention have been described, those skilled in the art will readily appreciate that many modifications are possible in the embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the claims. Therefore, it is to be understood that the foregoing is illustrative of the present invention and is not to be construed as limited to the specific embodiments disclosed, and that modifications to the disclosed embodiments, as well as other embodiments, are intended to be included within the scope of the appended claims. The invention is defined by the following claims, with equivalents of the claims to be included therein. We Claim: 1. A tuyere assembly installed at a melter-gasifier for forming melted iron, comprising: a tuyere including a gas passage used for injecting an oxygen- containing gas inside the melter-gasifier; and a pair of fuel injection lines spaced apart from each other and spaced apart from the gas passage to pass through the tuyere, and injecting an auxiliary fuel into the melter-gasifier. 2. The tuyere assembly of Claim 1, further comprising a fuel supplying line providing the auxiliary fuel to the pair of fuel injection lines, wherein the pair of fuel injection lines are provided with the auxiliary fuel from the fuel supplying line. 3. The tuyere assembly of Claim 2, wherein the auxiliary fuel is provided from the fuel supplying line in a first direction, the auxiliary fuel provided in the first direction is diverged in a second direction intersecting the first direction, and the auxiliary fuel is injected to the melter-gasifier through the pair of fuel injection lines in a third direction intersecting the second direction. 4. The tuyere assembly of Claim 3, wherein the first direction is substantially the same as the second direction. 5. The tuyere assembly of Claim 3, wherein the first direction is substantially perpendicular to the second direction. 6. The tuyere assembly of Claim 3, wherein the amounts of auxiliary fuel respectively diverged in the second direction are substantially the same. 7. The tuyere assembly of Claim 2, further comprising a diverged line connecting the fuel supplying line to the pair of fuel injection lines to diverge the auxiliary fuel provided through the fuel supplying line into fuel injection lines, respectively. 8. The tuyere assembly of Claim 7, wherein the diverged line comprises: a first diverged portion connected to the fuel supplying line and extending in a first direction; and at least one second diverged portion connected to the first diverged portion and extending in a second direction intersecting the first direction to be connected to each of the fuel injection lines. 9. The tuyere assembly of Claim 8, wherein the second diverged line and the fuel injection line are connected to each other and the second diverged line intersects the fuel injection line. 10. The tuyere assembly of Claim 1, wherein the fuel injection line is bent. 11. The tuyere assembly of Claim 8, wherein the fuel supplying line extends in the first direction. 12. The tuyere assembly of Claim 8, wherein the at least one second diverged portion includes a pair of second diverged portions and the second diverged portions are connected to both sides of the first diverged portion. 13. The tuyere assembly of Claim 8, wherein an average cross- section of the first diverged portion formed by cutting the first diverged portion in the second direction is larger than a cross-section of the fuel supplying line formed by cutting the fuel supplying line in the second direction. 14. The tuyere assembly of Claim 8, wherein an average cross- section of the second diverged portion formed by cutting the second diverged portion in the first direction is substantially larger than a cross- section of the fuel injection line formed by cutting the fuel injection line in the second direction. 15. The tuyere assembly of Claim 8, wherein an average cross- section of the first diverged portion formed by cutting the first diverged portion in the first direction is no more than an average cross-section of the second diverged portion formed by cutting the second diverged portion in the first direction. 16. The tuyere assembly of Claim 1, wherein the pair of fuel injection lines includes first end portions where auxiliary fuel contacts an inner portion of the melter-gasifier, the gas passage includes a second end portion where the oxygen-containing gas contacts the inner portion of the melter-gasifier, and imaginary lines connecting the first and second end portions form a triangle. 17. The tuyere assembly of Claim 16, wherein the triangle is a substantial isosceles triangle and the second end portion is located on a vertex portion of the isosceles triangle. 18. The tuyere assembly of Claim 1, wherein the auxiliary fuel is coal dust or a hydrocarbon-containing gas. 19. The tuyere assembly of Claim 1, wherein a direction in which the pair of fuel injection lines extends forms an acute angle with a direction in which the gas passage extends. 20. The tuyere assembly of Claim 19, wherein the acute angle is about 10° to about 40°. 21. The tuyere assembly of Claim 1, wherein the auxiliary fuel and the oxygen-containing gas are mixed together at a position spaced apart from a front end of the tuyere.

Full Text

Technical Field

This application claims priority to and the benefit of Korean Patent Application No. 2007-0135976 filed on December 24, 2007 in the Korean Intellectual Property Office, the entire content of which is incorporated herein by reference.

The present invention relates to a tuyere used for forming molten iron. More particularly, the present invention relates to a tuyere that is capable of effectively injecting auxiliary fuel. Background Art

Recently, a smelting reduction method that is capable of replacing the conventional blast furnace method has been developed. In the smelting reduction method, raw coal is directly used as a fuel and a reducing agent, and iron ore is directly used as an iron source. The iron ore is reduced in the reduction reactor and molten iron is formed in the melter-gasifier.

A tuyere is formed at a side face of the melter-gasifier. Oxygen is injected into the melter-gasifier through the tuyere, and the oxygen may burn a char bed formed in the melter-gasifier. Thus, melted iron is manufactured by melting the iron ore charged in the melter-gasifier by using the heat of combustion.

DISCLOSURE Technical Problem A tuyere assembly that is capable of improving the combustion rate of auxiliary fuel by injecting auxiliary fuel through a pair of fuel injection lines is provided. Technical Solution

In accordance with embodiments of the present invention, a tuyere assembly installed at a melter-gasifier for forming melted iron includes a tuyere where a gas passage used for injecting an oxygen-containing gas into the inside of the melter-gasifier and a pair of fuel injection lines spaced apart

from each other. The injection lines are spaced apart from the gas passage to pass through the tuyere. The injection lines inject auxiliary fuel into the melter-gasifier.

The tuyere assembly may further include a fuel supplying line providing the auxiliary fuel to the pair of fuel injection lines. The pair of fuel injection lines may be provided with the auxiliary fuel from the fuel supplying line.

The auxiliary fuel may be provided from the fuel supplying line in a first direction, the auxiliary fuel provided in the first direction may be diverged in a second direction intersecting the first direction, and the auxiliary fuel may be injected to the melter-gasifier through the pair of fuel injection lines in a third direction intersecting the second direction. The first direction may be substantially the same as the second direction, and the first direction may be substantially perpendicular to the second direction. The amounts of auxiliary fuel respectively diverged in the second direction may be substantially the same as one another.

The tuyere assembly may further include a diverged line connecting the fuel supplying line to the pair of fuel injection lines to diverge the auxiliary fuel provided through the fuel supplying line into fuel injection lines, respectively. The diverged line may include a first diverged portion connected to the fuel supplying line and extending in a first direction, and at least one second diverged portion connected to the first diverged portion and extending in a second direction intersecting the first direction to be connected to each of the fuel injection lines. The second diverged line and the fuel injection lines may be connected to each other, and the second diverged line intersects the fuel injection lines. The fuel injection lines may be bent. The fuel supplying line may extend in the first direction. The at least one second diverged portion may include the pair of second diverged portions, and each of the second diverged portions are connected to both sides of the first diverged portion.

An average cross-section of the first diverged portion formed by

cutting the first diverged portion in the second direction may be larger than a cross-section of the fuel supplying line formed by cutting the fuel supplying line in the second direction. An average cross-section of the second diverged portion formed by cutting the second diverged portion in the first direction may be substantially larger than a cross-section of the fuel injection line formed by cutting the fuel injection line in the second direction. An average cross-section of the first diverged portion formed by cutting the first diverged portion in the first direction may be no more than an average cross- section of the second diverged portion formed by cutting the second diverged portion in the first direction.

The pair of fuel injection lines may include first end portions where auxiliary fuel contacts an inner portion of the melter-gasifier. The gas passage may include a second end portion where the oxygen-containing gas contacts the inner portion of the melter-gasifier. Imaginary lines connecting the first and second end portions may form a triangle, and the triangle may substantially be an isosceles triangle. The second end portion may be located on a vertex portion of the isosceles triangle.

The auxiliary fuel may be a coal dust or a hydrocarbon-containing gas. A direction in which the pair of the fuel injection lines extends may form an acute angle with a direction in which the gas passage extends, and the acute angle may be about 10° to about 40°. The auxiliary fuel and the oxygen-containing gas may be mixed together at a position spaced apart from a front end of the tuyere. Advantageous Effects An auxiliary fuel is injected into a melter-gasifier through a fuel supplying line so that the combustion rate of an auxiliary fuel may be improved.

DESCRIPTION OF DRAWINGS FIG. 1 is a perspective view schematically illustrating a tuyere assembly 100 in accordance with a first embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1.

FIG. 3 schematically illustrates a cross-sectional structure of the tuyere assembly 200 in accordance with a second embodiment of the present invention.

FIG. 4 schematically illustrates a cross-sectional structure of a tuyere assembly 300 in accordance with a third embodiment of the present invention.

FIG. 5 schematically illustrates an operation state of the tuyere assembly 100 in accordance with the first embodiment of the present invention. FIG. 6 schematically illustrates a melter-gasifier 500 where the tuyere assembly 100 in accordance with the first embodiment of the present invention is installed.

BEST MODE The present invention will be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are illustrated. The invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

It will be understood that when an element or layer is referred to as being "on," "connected to," and/or "coupled to" another element or layer, the element or layer may be directly on, connected, and/ or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on," "directly connected to," and/ or "directly coupled to" another element or layer, no intervening elements or layers are present.

It will also be understood that, although the terms "first," "second," etc., may be used herein to describe various elements, components, regions, layers, and/ or sections, these elements, components, regions, layers and/ or sections should not be limited by these terms. Rather, these terms are used merely as a convenience to distinguish one element, component, region, layer, and/or section from another element, component, region, layer,

and/ or section. For example, a first element, component, region, layer, and/ or section could be termed a second element, component, region, layer, and/ or section without departing from the teachings of the present invention.

Spatially relative terms, such as "beneath," "below," "lower," "above," "upper," and the like, may be used to describe an element and/or feature's relationship to another element(s) and/or feature(s) as, for example, illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use and/ or operation in addition to the orientation depicted in the figures. For example, when the device in the figures is turned over, elements described as below and/ or beneath other elements or features would then be oriented above the other elements or features. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein are to be interpreted accordingly. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit of the invention. As used herein, the singular terms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "includes" and "including" specify the presence of stated features, integers, steps, operations, elements, and/ or components, but do not preclude the presence and/ or addition of one or more other features, integers, steps, operations, elements, components, and/ or groups thereof.

As used herein, the expressions "at least one," "one or more," and "and/ or" are open-ended expressions that are both conjunctive and disjunctive in operation. For example, each of the expressions "at least one of A, B, and Q1" "at least one of A, B, or C," "one or more of A, B, and Q1" "one or more of A, B, or Q1" and "A, B, and/ or C" includes the following meanings: A alone; B alone; C alone; both A and B together; both A and C together; both B and C together; and all three of A, B, and C together. Further, these expressions are open-ended, unless expressly designated to the contrary by their combination with the term "consisting of." For example, the expression "at least one of A, B, and C" may also include a fourth member, whereas the expression "at least one selected from the group consisting of A, B, and C" does not.

As used herein, the expression "or" is not an "exclusive or" unless it is used in conjunction with the phrase "either." For example, the expression "A, B, or C" includes A alone; B alone; C alone; both A and B together; both A and C together; both B and C together; and all three of A, B, and, C together, whereas the expression "either A, B, or C" means one of A alone, B alone, and C alone, and does not mean any of both A and B together; both A and C together; both B and C together; and all three of A, B, and C together.

Unless otherwise defined, all terms (including technical and scientific terms) used herein may have the same meaning as what is commonly understood by one of ordinary skill in the art. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized and/ or overly formal sense unless expressly so defined herein. Embodiments of the present invention may be described with reference to cross-sectional illustrations, which are schematic illustrations of idealized embodiments of the present invention. As such, variations from the shapes of the illustrations, as a result, for example, of manufacturing techniques and/ or tolerances, are to be expected. Thus, embodiments of the present invention should not be construed as limited to the particular shapes of regions illustrated herein, but are to include deviations in shapes that result from, e.g., manufacturing. For example, a region illustrated as a rectangle may have rounded or curved features. Thus, the regions illustrated in the figures are schematic in nature and are not intended to limit the scope of the present invention. Like reference numerals refer to like elements throughout.

FIG. 1 is a perspective view schematically illustrating a tuyere assembly 100 in accordance with a first embodiment of the present invention. FIG. 1 illustrates a structure of the tuyere assembly 100 from a viewpoint of a melter-gasifier. As illustrated in FIG. 1, the structure of the tuyere assembly 100 is an example, and the present invention is not limited by the structure. As a result, the structure of the tuyere assembly 100 may be varied.

As illustrated in FIG. 1, first end portions 20a and second end portions 1011 are formed at a front end portion 105 of the tuyere 10. The pair of fuel injection lines 20 includes first end portions 201. A gas passage

101 includes the second end portion 1011, and the gas passage 101 is connected to a gas supplying line 60 to provide an oxygen-containing gas. In the first end portion 20a, an auxiliary fuel is provided from the pair of fuel injection lines 20 to contact an inside of the melter-gasifier. In the second end portion 1011, the oxygen-containing gas is provided from the gas passage 101 to contact the inside of the melter-gasifier.

Referring to a dotted line in FIG. 1, if the first end portions 201 and the second end portions 1011 are connected to one another, a triangle is formed. In addition, the first end portions 201 are located such that a distance between the first end portion 201 and the second end portion 1011 is uniformly maintained. Thus, the triangle may be an isosceles triangle because the distance between the first end portion 201 and the second end portion 1011 is uniformly maintained. The second end portion 1011 is located at a vertex of the isosceles triangle. Hereinafter, a cross-section of the tuyere assembly 100 is explained with reference to FIG. 2.

FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1. The cross-sectional view in FIG. 2 is merely an example, so that the present invention is not limited in FIG. 2.

As illustrated in FIG. 2, the tuyere assembly 100 includes a tuyere 10 and a pair of fuel injection lines 20. The pair of the fuel injection lines 20 may be inserted in the tuyere 10. Further, the tuyere assembly 100 may include a fuel supplying line 30, a diverged line 40, and a gas supplying line 60. The gas supplying line 60 providing the oxygen-containing gas may pass below the fuel supplying line 30. As illustrated in FIG. 2, a gas passage 101 is formed at a central portion of the tuyere 10. To manufacture melted iron in the melter-gasifier 500, an oxygen-containing gas is injected to the inside of the melter-gasifier 500 through the gas passage 101. Here, the oxygen-containing gas includes an oxygen gas, a gas including an oxygen, etc. Thus, a hot wind including oxygen may be injected through the gas passage 101 besides the oxygen gas.

As illustrated in FIG. 2, a first cooling passage 107 and a second cooling passage 109 are formed inside the tuyere 10. The first cooling passage 107 and the second cooling passage 109 are isolated from each other. Cooling water flowing along the second cooling passage 109 may cool a body of the tuyere 10, and cooling water flowing along the first cooling passage

107 may cool a front end portion of the tuyere 10.

The front end portion 105 of the tuyere 10 is located in the melter- gasifier 500 so that the front end portion 105 of the tuyere 10 may be exposed to a relatively high temperature. Thus, the front end portion 106 of the tuyere 10 may be melted to break the cooling passage. If the cooling passage in the tuyere 10 is integrally formed, it is difficult to cool the tuyere 10 when the front end portion of the tuyere 10 is broken. Thus, the usage of the tuyere 10 may be stopped.

However, as illustrated in FIG. 2, the first cooling passage 107 and the second cooling passage 109 in the tuyere 10 are isolated.

The second cooling passage 109 may still operate even though the first cooling passage 107 is broken when the front end portion of the tuyere 10 is exposed to the relatively high temperature. This is because the second cooling passage 109 is isolated from the first cooling passage 107. A cooling of the tuyere 10 is well known to a person skilled in the art so a detailed explanation is omitted.

A pair of fuel injection lines 20 are spaced apart from the gas passage 101. If the pair of fuel injection lines 20 meets the gas passage 101 in the tuyere 10, the auxiliary fuel provided through the pair of fuel injection lines 20 may react with the oxygen-containing gas provided through the gas passage 101. Thus, the tuyere 10 may be melted by the above reaction so that the tuyere 10 may be broken. As a result, the pair of fuel injection lines 20 is spaced apart from the gas passage 101.

As illustrated in FIG. 2, the pair of fuel injection lines 20 may pass through the tuyere 10. The auxiliary fuel is provided to the inside of the melter-gasifier 500 through the pair of fuel injection lines 20. Here, as an example, the auxiliary fuel may be coal dust or a hydrocarbon-containing gas. The dust coal includes carbon and has a diameter below about 3mm. Examples of the hydrocarbon-containing gas may include liquid natural gas (LNG), liquid propane gas (LPG), etc.

The auxiliary fuel is provided into the melter-gasifier 500 to increase heat of combustion. Thus, the amount of coal provided to an upper portion of the melter-gasifier 500 may be reduced. In addition, the auxiliary fuel may generate an amount of reduction gas so that iron ore may be effectively reduced. Furthermore, the coal provided to the upper portion of the melter-

gasifier 500 may be burned before the core reaches a lower portion of the melter-gasifier 500. Thus, the lower portion of the melter-gasifier 500 may be in a state that is unsuitable for manufacturing the melted iron. As a result, the auxiliary fuel may be provided to the lower portion of the melter- gasifier 500 to improve the state of the lower portion of the melter-gasifier 500.

As illustrated in FIG. 2, the pair of fuel injection lines 20 may be spaced apart from each other to inject the auxiliary fuel into the melter- gasifier 500. Thus, the auxiliary fuel is properly separated and then provided into the melter-gasifier 500 to increase the combustion rate of the auxiliary fuel.

In accordance with the first embodiment to the present invention, the pair of fuel injection lines 20 are used instead of one fuel injection line to provide the inside of the melter-gasifier 500 with the auxiliary fuel. If one fuel injection line is used, one amount of the auxiliary fuel is provided into the melter-gasifier 500 at a time. Thus, an oxygen-containing gas is required to satisfy a relatively large combustion rate. Thus, it is difficult to burn an amount of fine coal. On the other hand, if the pair of fuel injection lines 20 are used as illustrated in the first embodiment, the auxiliary fuel is uniformly dispersed into the fuel injection line 20 and then provided into the melter- gasifier 500. Thus, the oxygen-containing gas may burn a relatively small amount of auxiliary fuel so that the oxygen-containing gas is required to satisfy a relatively small combustion rate. As a result, the auxiliary fuel may be effectively burned by the oxygen-containing gas. Consequently, the melter-gasifier 500 may be operated more effectively.

At least three fuel injection lines may be used. If three injection lines are used, three injection lines are required to be inserted into the tuyere. Thus, a structure of the tuyere 10 may become relatively complex. For example, it is difficult to form a cooling passage for cooling the tuyere 10 such that the cooling passage avoids three fuel injection lines. Thus, a cost for designing the tuyere 10 may increase. In addition, if three fuel injection lines are used, the combustion rate of the fine coal may not be larger than that in a case where the pair of fuel injection lines is used. Thus, it is appropriate to use the pair of the fuel injection lines. Each of the fuel injection lines 20 is provided with the auxiliary fuel

from the fuel supplying line 30. The auxiliary fuel is provided to the fuel supplying line 30 and then diverged in the diverged line 40. Thereafter, the auxiliary fuel is provided to the fuel injection lines 20. A flange 207 and a valve 209 are installed at the fuel injection line 20. The auxiliary fuel flowing through the fuel injection line 20 may be blocked by the valve 209.

The diverged line 40 may divide the auxiliary fuel provided from the fuel supplying line 30 into the fuel injection line 20. The diverged line 40 may be connected to the fuel supplying line 30 and the pair of fuel injection lines 20 by flanges 207 and 309. The diverged line 40 includes a first diverged portion 401 and a second diverged portion 403. In addition, the diverged portion 40 includes three chambers 4011 and 4013. The first diverged portion 401 is connected to the fuel supplying line 30. The first diverged portion 401 extends in an x-direction. The pair of second diverged lines 403 is connected to the first diverged portion 401. The second diverged lines 403 are connected to both side portions of the first diverged portion 401, respectively. The second diverged lines 403 are connected such that they intersect the fuel injection line 20. The second diverged portions 403 extend in ±y-axis directions, respectively. As illustrated in FIG. 2, the diverged portion 40 has a "T" shape. The auxiliary fuel may sequentially pass through the fuel supplying line 30, the diverged line 40, and the pair of the fuel injection lines 20 to be injected into the melter-gasifier 500. Hereinafter, a direction in which the auxiliary fuel passing through the tuyere assembly 100 is transferred is described in more detail with reference to FIG. 2. As illustrated in FIG. 2, the auxiliary fuel is provided from the fuel supplying line 30 in a first direction (i.e., +x-axis direction). Thus, the fuel supplying line 30 extends in the first direction. The auxiliary fuel passes through the diverged line 40 so that the auxiliary fuel may be diverged in a second direction (i.e., +y-axis direction and -y-axis direction). The auxiliary fuel is then provided from the diverged line 40 toward the fuel injection line 20 in a third direction. The third direction may form an acute angle with a direction in which the gas passage 101 extends. Thus, the auxiliary fuel provided from the fuel injection line 20 may be effectively mixed with the oxygen-containing gas provided from the gas passage 101. The first direction and the second direction may be perpendicular to each other.

As described above, a proceeding direction of the auxiliary fuel may be largely changed when the auxiliary fuel passes through the diverged line 40. However, the auxiliary fuel may not flow backward or stop. This is because a space where the auxiliary fuel is received is maximized by using three chambers 4011 and 4013. Furthermore, an inner diameter may decrease from the chamber 4013 to the fuel injection line 20 so that a velocity of the auxiliary fuel may be increased. Thus, the auxiliary fuel may be sprayed toward the melter-gasifier 500. The amounts of the auxiliary fuels diverged in the second direction, respectively, may be substantially the same. Thus, the auxiliary fuels may be effectively burned in the melter-gasifier 500. This is illustrated in more detail with reference to a structure of the diverged line 40 in FIG. 2.

As illustrated in FIG. 2, a cross-section S401 is a cross-section of the first diverged portion 401 taken in the y-axis direction. Here, an average cross-section is an average of a sum of the cross-section S401 obtained by cutting the first diverged portion 401 in the y-axis direction. In addition, a cross-section S403 is a cross-section of the second diverged portion 403 taken in the x-axis direction. Here, an average cross-section is an average of a sum of the cross-section S403 obtained by cutting the second diverged portion 403 in the x-axis direction. A cross-section S30 of the fuel supplying line 30 is a cross-section obtained by cutting the fuel supplying line 30 in the y-axis direction. In addition, a cross-section S20 of the fuel injection line 20 is a cross-section obtained by cutting the fuel injection line 20 in the y-axis direction. The average cross-section of the first diverged portion 401 is relatively larger than the cross-section S30 of the fuel supplying line 30. That is, an inner diameter of the first diverged portion 401 is large because the first diverged portion 401 includes the chamber 4011. Thus, the auxiliary fuel is effectively supplied from the fuel supplying line 30 to the diverged line 40.

In addition, the average cross-section of the second diverged portion 403 is larger than the cross-section S20 of the fuel injection line 20. That is, an inner diameter of the second diverged portion 403 is large because the second diverged portion 403 includes the chamber 4031. Thus, the auxiliary fuel is rapidly supplied from the second diverged portion 403 to the fuel

injection line 20. As a result, the combustion rate of the auxiliary fuel may be improved in the melter-gasifier 500.

Furthermore, the average cross-section of the first diverged portion 401 is no less than the average cross-section of the second diverged portion 403. Thus, the auxiliary fuel may be rapidly supplied from the first diverged portion 401 toward the second diverged portion 403 because the average cross-section of the first diverged portion 401 is no more than the average cross-section of the second diverged portion 403.

As a result, flow velocity of the auxiliary fuel may not be largely reduced even though the proceeding direction of the auxiliary fuel is changed when the auxiliary fuel is supplied from the first diverged portion 401 to the second diverged portion 403.

FIG. 3 schematically illustrates a cross-sectional structure of the tuyere assembly 200 in accordance with the second embodiment of the present invention. The structure of the tuyere assembly 200 is substantially the same as the structure of the tuyere assembly 100 in FIG. 2 except for a fuel injection line 22. Thus, the same reference numerals will be used to refer to the same or like parts and further explanation will be omitted.

As illustrated in FIG. 3, the fuel injection line 22 is bent. The fuel injection line 22 is connected to the diverged line 40 and then bent to be inserted into the tuyere 10. Here, the fuel injection line 22 is connected to the second diverged line 403 in a direction (i.e., the x-axis direction) perpendicularly intersecting a direction (i.e., the y-axis direction) in which the second diverged line 403 extends. Thus, a connection between the fuel injection line 22 and the second diverged line 403 may be relatively rigid.

As illustrated in FIG. 3, the fuel injection line 22 is bent in a direction becoming close to the gas passage 101 so that the auxiliary fuel sprayed from the fuel injection line 22 may be effectively mixed with the oxygen- containing gas sprayed from the gas passage 101. The combustion rate of the auxiliary fuel may be improved because the auxiliary fuel is effectively mixed with the oxygen-containing gas.

FIG. 4 schematically illustrates a cross-sectional structure of a tuyere assembly 300 in accordance with a third embodiment of the present invention. The cross-sectional structure of the tuyere assembly 300 in FIG. 4 is substantially similar to the cross-sectional structure of the tuyere assembly

200 in FIG. 3. Thus, the same reference numerals will be used to refer to the same or like parts and further explanation will be omitted.

As illustrated in FIG. 4, the tuyere assembly 300 may be manufactured by using a diverged line 42 having a "Y" shape. The diverged line 42 may be combined with a fuel injecting line 30 by a flange

309, and may be combined with a fuel injection line 20 by a flange 207.

Flow velocity of the auxiliary fuel provided through the fuel injecting line 30 may not be largely reduced because the diverged line 42 has the "Y" shape.

The auxiliary fuel may be provided through the fuel injection line 20 such that the flow velocity of the auxiliary fuel may not be largely reduced.

FIG. 5 schematically illustrates an operation state of the tuyere assembly 100 in accordance with the first embodiment of the present invention.

As illustrated in FIG. 5, a char bed formed from coal or coke is located at a front portion of the tuyere 10. Here, if the oxygen-containing gas is injected through the gas passage 101, a reduction gas may be generated in forming a raceway at the char bed. In addition, if the auxiliary fuel is injected through the pair of fuel injection lines 20, the auxiliary fuel is directly injected to the raceway so that a reduction gas may be additionally generated. Thus, the amount of reduction gas generated in the melter- gasifier 500 may be maximized and the amount of coal provided to the melter-gasifier 500 may be minimized.

Here, a direction in which the pair of the fuel injection lines 20 extends may form an acute angle (?) with a direction in which the gas passage 101 extends. Thus, an injection direction of the auxiliary fuel injected through the pair of the fuel injection lines 20 may form an acute angle (?) with a central line (C) of the tuyere 10. The acute angle (?) may be about 10° to about 40°.

If the acute angle (?) is less than about 10°, an auxiliary fuel injected from the fuel injection line 20 may not effectively meet an oxygen-containing gas injected from the gas passage 101. Thus, an ignition of the auxiliary fuel may be delayed. If the acute angle ? is larger than about 40°, the auxiliary fuel and the oxygen-containing gas may meet at front of a front portion 105 of the tuyere 10 so that the ignition may be achieved. Thus, the front end portion 105 of the tuyere may be melted and then damaged. As a result, the

acute angle (?) may be managed in a range of about 10° to about 40°

FIG. 6 schematically illustrates a melter-gasifier 500 where the tuyere assembly 100 in accordance with the first embodiment of the present invention is installed. Iron ore and coal are charged from an upper portion of the melter- gasifier 500 and then discharged after melted iron is manufactured in the melter-gasifier 500. Here, the iron ore may be charged as reduced iron, and the coal may be charged in the shape of briquettes that may be charged into the melter-gasifier 500 to form a char bed (see FIG. 5) and produce a reduction gas that is to be exhausted outward. The char bed may be burned by the oxygen-containing gas charged through the tuyere assembly 100 to produce heat of combustion. The reduced iron may be melted by the heat of combustion so that the melted iron may be manufactured. The reduction gas exhausted from the melter-gasifier 500 may be provided into the fluidized-bed reduction furnace or the packed-bed reduction furnace so that the reduction gas may reduce the iron ore charged to the fluidized-bed reduction furnace or the packed-bed reduction furnace. As a result, the reduced iron may be manufactured.

In accordance with the first embodiment of the present invention, the oxygen-containing gas and auxiliary fuel may be charged through the tuyere assembly 100 so that the heat of combustion in the melter-gasifier 500 may increase. As a result, the amount of briquettes charged from the upper portion of the melter-gasifier 500 may be reduced. Here, the auxiliary fuel may be injected to the inside of the melter-gasifier 500 through the pair of fuel injection lines. Thus, a combustibility of the auxiliary fuel may be improved.

Example

Fine coal was injected to the melter-gasifier as an auxiliary fuel by using a tuyere assembly having a structure as in FIG. 1. The fine coal was injected to the melter-gasifier through the tuyere assembly by using the pair of fuel injection lines. In addition, pure oxygen was provided to the melter- gasifier through a gas passage of the tuyere assembly. The amount of fine coal injected through the fuel supplying line was about 250kg/ t-p, and the amount of fine coal injected through each diverged fuel injection lines was about 125kg/ t-p. Combustibility of the fine coal was measured at the front

of the tuyere. The combustibility of the fine coal was about 95%. Comparative Example

Contrary to the example, fine coal was injected to a melter-gasifier by using a tuyere assembly including only one fuel injection line. The fine coal was injected to the melter-gasifier through the fuel injection line. In addition, pure oxygen was injected to the melter-gasifier through a gas passage of the tuyere assembly. The amount of fine coal injected through the fuel injection line was about 150kg/t-p. Combustibility of the fine coal was measured at the front of the tuyere. The combustibility of the fine coal was about 75%.

As described in the example and comparative example, the combustibility of the fine coal in the example was about 20% greater than that in the comparative example. Thus, when the pair of fuel injection lines are used, the combustion rate of the fine coal injected to the melter-gasifier through the tuyere may be improved compared with the case where one fuel injection line is used. This is because the oxygen gas may not fully burn the fine coal when a large amount of fine coal is charged into the melter-gasifier at a time, because the oxygen-containing gas is required to burn the fine coal. That is, a large combustion burden is applied to the oxygen-containing gas. On the other hand, when the fine coal is injected through the pair of fuel injection lines, a small amount of the fine coal is dispersed and then injected to the melter-gasifier. Thus, a large amount of combustion burden may not be applied to the oxygen-containing gas. As a result, the oxygen gas may fully burn the fine coal. The foregoing is illustrative of the present invention and is not to be construed as limiting thereof. Although a few embodiments of this invention have been described, those skilled in the art will readily appreciate that many modifications are possible in the embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the claims. Therefore, it is to be understood that the foregoing is illustrative of the present invention and is not to be construed as limited to the specific embodiments disclosed, and that modifications to the disclosed embodiments, as well as other embodiments, are intended to be included within the scope of the appended

claims. The invention is defined by the following claims, with equivalents of the claims to be included therein.

We Claim:

1. A tuyere assembly installed at a melter-gasifier for forming melted iron, comprising: a tuyere including a gas passage used for injecting an oxygen- containing gas inside the melter-gasifier; and a pair of fuel injection lines spaced apart from each other and spaced apart from the gas passage to pass through the tuyere, and injecting an auxiliary fuel into the melter-gasifier.

2. The tuyere assembly of Claim 1, further comprising a fuel supplying line providing the auxiliary fuel to the pair of fuel injection lines, wherein the pair of fuel injection lines are provided with the auxiliary fuel from the fuel supplying line.

3. The tuyere assembly of Claim 2, wherein the auxiliary fuel is provided from the fuel supplying line in a first direction, the auxiliary fuel provided in the first direction is diverged in a second direction intersecting the first direction, and the auxiliary fuel is injected to the melter-gasifier through the pair of fuel injection lines in a third direction intersecting the second direction.

4. The tuyere assembly of Claim 3, wherein the first direction is substantially the same as the second direction.

5. The tuyere assembly of Claim 3, wherein the first direction is substantially perpendicular to the second direction.

6. The tuyere assembly of Claim 3, wherein the amounts of auxiliary fuel respectively diverged in the second direction are substantially the same.

7. The tuyere assembly of Claim 2, further comprising a diverged line connecting the fuel supplying line to the pair of fuel injection

lines to diverge the auxiliary fuel provided through the fuel supplying line into fuel injection lines, respectively.

8. The tuyere assembly of Claim 7, wherein the diverged line comprises: a first diverged portion connected to the fuel supplying line and extending in a first direction; and at least one second diverged portion connected to the first diverged portion and extending in a second direction intersecting the first direction to be connected to each of the fuel injection lines.

9. The tuyere assembly of Claim 8, wherein the second diverged line and the fuel injection line are connected to each other and the second diverged line intersects the fuel injection line.

10. The tuyere assembly of Claim 1, wherein the fuel injection line is bent.

11. The tuyere assembly of Claim 8, wherein the fuel supplying line extends in the first direction.

12. The tuyere assembly of Claim 8, wherein the at least one second diverged portion includes a pair of second diverged portions and the second diverged portions are connected to both sides of the first diverged portion.

13. The tuyere assembly of Claim 8, wherein an average cross- section of the first diverged portion formed by cutting the first diverged portion in the second direction is larger than a cross-section of the fuel supplying line formed by cutting the fuel supplying line in the second direction.

14. The tuyere assembly of Claim 8, wherein an average cross- section of the second diverged portion formed by cutting the second diverged portion in the first direction is substantially larger than a cross-

section of the fuel injection line formed by cutting the fuel injection line in the second direction.

15. The tuyere assembly of Claim 8, wherein an average cross- section of the first diverged portion formed by cutting the first diverged portion in the first direction is no more than an average cross-section of the second diverged portion formed by cutting the second diverged portion in the first direction.

16. The tuyere assembly of Claim 1, wherein the pair of fuel injection lines includes first end portions where auxiliary fuel contacts an inner portion of the melter-gasifier, the gas passage includes a second end portion where the oxygen-containing gas contacts the inner portion of the melter-gasifier, and imaginary lines connecting the first and second end portions form a triangle.

17. The tuyere assembly of Claim 16, wherein the triangle is a substantial isosceles triangle and the second end portion is located on a vertex portion of the isosceles triangle.

18. The tuyere assembly of Claim 1, wherein the auxiliary fuel is coal dust or a hydrocarbon-containing gas.

19. The tuyere assembly of Claim 1, wherein a direction in which the pair of fuel injection lines extends forms an acute angle with a direction in which the gas passage extends.

20. The tuyere assembly of Claim 19, wherein the acute angle is about 10° to about 40°.

21. The tuyere assembly of Claim 1, wherein the auxiliary fuel and the oxygen-containing gas are mixed together at a position spaced apart from a front end of the tuyere.

Documents:

1182-MUMNP-2010-CLAIMS(AMENDED)-(22-11-2013).pdf

1182-MUMNP-2010-CLAIMS(MARKED COPY)-(22-11-2013).pdf

1182-MUMNP-2010-CORRESPONDENCE(15-11-2010).pdf

1182-MUMNP-2010-CORRESPONDENCE(22-11-2010).pdf

1182-MUMNP-2010-CORRESPONDENCE(30-7-2012).pdf

1182-MUMNP-2010-CORRESPONDENCE(8-6-2010).pdf

1182-MUMNP-2010-FORM 1(22-11-2010).pdf

1182-MUMNP-2010-FORM 1(30-7-2012).pdf

1182-MUMNP-2010-FORM 13(30-7-2012).pdf

1182-MUMNP-2010-FORM 18(8-6-2010).pdf

1182-MUMNP-2010-FORM 3(15-11-2010).pdf

1182-MUMNP-2010-FORM 3(22-11-2013).pdf

1182-MUMNP-2010-OTHER DOCUMENT(22-11-2013).pdf

1182-MUMNP-2010-PETITION UNDER RULE-137(22-11-2013).pdf

1182-MUMNP-2010-REPLY TO EXAMINATION REPORT(22-11-2013).pdf

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Patent Number

258889

Indian Patent Application Number

1182/MUMNP/2010

PG Journal Number

07/2014

Publication Date

14-Feb-2014

Grant Date

13-Feb-2014

Date of Filing

03-Jun-2010

Name of Patentee

POSCO

Applicant Address

1 Goedong-dong Nam-ku Pohang-shi Kyungsangbuk-do 790-300 Korea

Inventors:

#	Inventor's Name	Inventor's Address
1	CHOI Eung-Soo	c/o POSCO Dongchon-dong 5 Nam-ku Pohang-shi Kyungsangbuk-do 790-360 Korea
2	SEO Weon-Seog	c/o POSCO Dongchon-dong 5 Nam-ku Pohang-shi Kyungsangbuk-do 790-360 Korea
3	BAE Jin-Chan	c/o POSCO Dongchon-dong 5 Nam-ku Pohang-shi Kyungsangbuk-do 790-360 Korea

PCT International Classification Number

C21B 7/16

PCT International Application Number

PCT/KR2008/007478

PCT International Filing date

2008-12-17

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	10-2007-0135976	2007-12-24	Republic of Korea