Sintering ignition device and method for designing a sintering ignition device

Abstract

To provide an ignition device for sintering improved in yield in manufacturing sintered ore by re-ignition sintering technology.SOLUTION: An ignition device for sintering used for a sintering machine has two ignition furnaces separately provided in the strand traveling direction. A separation distance between a first ignition furnace burner nozzle upstream the strand traveling direction and a second ignition furnace burner nozzle downstream the strand traveling direction is composed to be variable. Ignition intensity (ignition heat quantity per 1 ton of raw material) of the first ignition furnace burner and the ignition intensity of the second ignition furnace burner is composed to be variable.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a sintering ignition device provided in an iron ore sintering machine, in particular an ignition device having two ignition furnaces, and a method for designing a sintering ignition device. [Background technology]

[0002] Sintered ore, the main raw material for blast furnace pig iron production, is produced by a sintering machine. A downward suction type Dwight Lloyd (DL) sintering machine (hereinafter simply referred to as a sintering machine) is equipped with an ignition furnace on the upstream side of the machine length direction, and ignites the upper layer (surface layer) of the raw material packed bed (raw material layer) placed on a pallet. While the ignited raw material layer moves downstream, the combustion of the coagulant in the raw material layer progresses toward the lower layer by downward suction, and a sintered body (sinter cake) is obtained. The obtained sintered body (sinter cake) is crushed, sieved, etc. to be sized to a specified grain size to become sintered ore, the raw material for blast furnace pig iron production.

[0003] Regarding the ignition furnace of a sintering machine, the following techniques have been disclosed. Patent Document 1 discloses a technology for moving an ignition furnace in the machine length direction in a sintering machine equipped with one ignition furnace. When changing the pallet speed according to the production volume, the distance from the ignition position to the ore discharge position is adjusted to keep the sintering time (especially the cooling time) constant and suppress the deterioration of the reduction decay index (RDI).

[0004] Patent Document 2 discloses a technique (re-ignition sintering technique) for intermittently igniting a raw material layer twice using a sintering machine equipped with two ignition furnaces arranged in series at a predetermined distance apart in the machine length direction. The appropriate time (hereinafter referred to as separation time) from ignition by the first ignition furnace to ignition (re-ignition) by the second ignition furnace (re-ignition furnace) is 0.5 to 3 minutes. Here, the separation time is the time required for the raw material layer (pallet) to move the distance (separation distance) from directly below the burner nozzle (ignition burner nozzle) of the first ignition furnace to directly below the burner nozzle (re-ignition burner nozzle) of the second ignition furnace (separation distance movement time). Note that, at present, this separation time is determined based on equipment factors such as arranging the ignition furnace on the wind box of the sintering machine within the above-mentioned appropriate range. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Utility Model Application Publication No. 59-34299 [Patent Document 2] JP 2020-2457 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the operation by the re-ignition sintering technology, it is necessary to optimize the ignition strength (ignition heat amount per unit raw material) of the first and second ignition furnaces and the separation time. Here, in the technology disclosed in Patent Document 2, for example, when the pallet speed is changed during operation to adjust the production volume, the ignition strength can be kept constant by adjusting the amount of combustible gas supplied to the burner. However, the separation time cannot be adjusted because the two ignition furnaces are fixed, and there is a problem that the separation time increases and decreases with the increase and decrease of the pallet speed, resulting in a decrease in yield. In addition, when designing the sintering ignition device (hereinafter also simply referred to as the ignition device), the separation distance between the two ignition furnaces may not be appropriate, resulting in a decrease in yield.

[0007] The technology disclosed in Patent Document 1 is a technology related to a sintering machine equipped with only one ignition furnace, and the distance from the ignition position of the single ignition furnace to the ore discharge position is adjustable to suppress deterioration of reduction disintegration. Since there is only one ignition furnace, there is no description of the concept of separation distance.

[0008] The present invention provides a sintering ignition device and a method for designing a sintering ignition device that can improve yields in the production of sintered ore using reignition sintering technology. [Means for solving the problem]

[0009] (1) A sintering ignition device for use in a sintering machine, comprising: The sintering ignition device has two ignition furnaces spaced apart from each other in the strand traveling direction, A distance between a burner nozzle of a first ignition furnace on the upstream side in the strand traveling direction and a burner nozzle of a second ignition furnace on the downstream side in the strand traveling direction is configured to be discontinuously changeable, 1. A sintering ignition device, characterized in that the ignition intensity (ignition heat amount per ton of raw material) of the burner of the first ignition furnace and the ignition intensity of the burner of the second ignition furnace are configured to be adjustable. (2) a burner nozzle of the first ignition furnace is fixed relative to the sintering machine; The sintering ignition device according to (1), wherein the burner nozzle of the second ignition furnace is provided movably relative to the sintering machine. (3) A method for designing a sintering ignition device of a second sintering machine having a pallet width larger than that of a first sintering machine having the sintering ignition device according to (1) or (2), comprising: The sintering ignition device of the second sintering machine is provided with two ignition furnaces having burner nozzles spaced apart in the strand traveling direction, determining an optimal required time for the pallet to move the separation distance during operation of the first sintering machine, which maximizes yield; A method for designing a sintering ignition device, characterized in that a separation distance of a burner nozzle of the sintering ignition device of the second sintering machine is determined based on a pallet speed applied during operation of the second sintering machine so that the time required for the pallet to move the separation distance in the sintering ignition device of the second sintering machine is equal to the optimal required time. (4) An ignition device for sintering, characterized by being designed based on the design method for an ignition device for sintering described in (3). Effect of the Invention

[0010] The yield can be improved by using a sintering ignition device that is configured so that the separation distance can be changed, or a sintering ignition device that is designed based on the operating results of a sintering machine that has this sintering ignition device. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a conceptual diagram illustrating a sintering reignition technique. [Diagram 2] FIG. 1 is a schematic diagram of a test sintering machine. [Diagram 3] FIG. 2 is a schematic diagram of a sintering ignition device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] A preferred embodiment of the present invention will be described below. First, since the sintering reignition technology is described in detail in the above-mentioned Patent Document 2, only the parts related to the present invention will be briefly described here with reference to the drawings.

[0013] [Sintering reignition technology] Fig. 1 is a conceptual diagram illustrating the sintering and re-ignition technique, in which two ignition operations are performed using two sets of ignition means (ignition furnace 2 and re-ignition furnace 4) that are spaced apart from each other. As shown in FIG. 1, in a sintering machine that realizes the sintering reignition technology, a reignition furnace 4 that reignites the upper surface of the raw material layer 1 is provided downstream of the ignition furnace 2. The upstream ignition furnace 2 and the downstream reignition furnace 4 are provided at a predetermined interval, and an air suction area 3 is provided between the two ignition furnaces, where air is sucked in by downward suction and heating is not performed from the top. Here, the distance (distance) between the burner nozzle of the ignition furnace 2 and the burner nozzle of the reignition furnace 4 in the sintering machine length direction (strand movement direction) is called the distance D1 between the burner nozzles of both ignition furnaces (hereinafter also simply referred to as the separation distance). In addition, the fuel used in the ignition furnace 2 and the reignition furnace 4 may be any combustible gas, and LPG or city gas is commonly used, but coke oven gas (COG) or converter gas (LDG) may be used in a steelworks.

[0014] The method for producing sintered ore using sintering and reignition technology is as follows. The granulated sintering raw material is loaded from a hopper 7 into a box-shaped pallet (not shown), forming the raw material layer 1. The pallets are arranged in the longitudinal direction of the sintering machine without gaps, and move downstream at a predetermined speed while carrying the formed raw material layer 1. Below the ignition furnace 2, the upper surface (surface) of the raw material layer 1 is ignited, and solid heat sources (aggregators) such as coke contained in the raw material layer 1 are burned. When the ignited raw material layer 1 moves to the air suction area 3, the combustion zone 5 descends due to downward suction, and the sintering reaction progresses from the upper surface to the lower surface. Below the re-ignition furnace 4, the upper surface (surface) of the raw material layer 1 is re-ignited and heated. Downstream of the re-ignition furnace 4, the combustion zone 5 descends again due to downward suction, and the sintered layer 6, where the combustion of the solid heat source is finally completed, is discharged. As shown in FIG. 1, while the ignition furnace 2 or the re-ignition furnace 4 is igniting, the combustion front 8 does not advance and stagnates. This is because the oxygen concentration above the raw material bed 1 becomes thin due to ignition or re-ignition, limiting the supply of oxygen and causing the combustion of the solid heat source in the raw material bed 1 to stagnate.

[0015] The present invention relates to a sintering ignition device used in a sintering machine implementing the above-mentioned sintering reignition technology, and has been devised based on the following considerations. In the sintering re-ignition technology, the time (separation time) T1 (min) required for the pallet to move from directly below the burner nozzle of the ignition furnace 2 to directly below the burner nozzle of the re-ignition furnace 4 is determined by the distance between the burner nozzles of both ignition furnaces (D1 (m)) and the pallet speed (vp (m / min)) according to the following formula (1). T1=D1 / vp...Formula (1)

[0016] On the other hand, the (re)ignition heat (J / t-raw material, hereinafter also referred to as ignition intensity Qig) by the ignition furnace 2 (or re-ignition furnace 4) per unit raw material (1 t of raw material) is calculated by dividing the (re)combustion heat (fuel amount) Qco (J / min) per unit time of the burner of the ignition furnace 2 (or re-ignition furnace 4) by the weight of raw material M (t / min) passing directly below the burner nozzle of the ignition furnace 2 (or re-ignition furnace 4) per unit time, as shown in the following equation (2). Qig = Qco / M Equation (2)

[0017] The weight of raw materials passing directly under the burner nozzle of the ignition furnace 2 (or reignition furnace 4) per unit time, M (t / min), is calculated by the pallet speed vp (m / min), pallet width w (m), raw material layer thickness H (m), and raw material packing density (charging density) ρ (t / min) of the ignition furnace 2 (or reignition furnace 4). 3 ) M=vp×w×H×ρ...Equation (3)

[0018] Here, when the pallet speed vp or the raw material layer thickness H is changed to adjust the production volume or yield fluctuation, the separation time T1 and (re)ignition intensity Qig also change accordingly. In order to always keep both at the optimum value, the separation time T1 can be adjusted by adjusting the distance (separation distance) D1 between the burner nozzles of both ignition furnaces in proportion to the raw material weight M. Also, the (re)ignition intensity Qig can be adjusted by adjusting the (re)combustion heat Qco in proportion to the pallet speed vp. The (re)combustion heat Qco can be adjusted by changing the opening degree of the burner flow control valve, but in order to keep the separation time T1 at the optimum value, it is necessary to make the separation distance D1 variable. In other words, by making the separation distance D1 variable, it is possible to optimize the separation distance D1 according to the operating conditions, and an improvement in the yield can be expected.

[0019] [Sintering ignition device] The sintering ignition device of the present invention is a sintering ignition device used when implementing the sintering re-ignition technology, and is characterized in that it has two ignition furnaces spaced apart in the strand traveling direction, and the distance D1 between the burner nozzle of the ignition furnace (first ignition furnace) upstream in the strand traveling direction and the burner nozzle of the ignition furnace (second ignition furnace) downstream in the strand traveling direction is changeable. The two ignition furnaces spaced apart in the strand traveling direction correspond to the above-mentioned ignition furnace 2 and re-ignition furnace 4. Each ignition furnace is equipped with a flow rate control valve that changes the amount of gaseous fuel supplied, and the ignition intensity of each burner is adjustable (changeable). In addition, in each ignition furnace, a plurality of nozzle holes are provided at equal intervals in the pallet width direction.

[0020] As a configuration in which the separation distance D1 can be changed, for example, the burner nozzles may be fixed to a predetermined position (such as the center) in the machine length direction of each ignition furnace, and the position of the upstream ignition furnace and / or the downstream ignition furnace in the sintering machine length direction may be movable relative to the sintering machine frame. Also, each ignition furnace may be fixed to the sintering ignition device, and the position of each burner nozzle in the sintering machine length direction may be movable within each ignition furnace.

[0021] A more preferable configuration of the sintering ignition device, which will be specifically described in the examples below, is to fix the upstream ignition furnace near the raw material supply device (charging chute 16 of hopper 17) that supplies the sintering raw materials, and to make the downstream re-ignition furnace movable, so that the separation distance D1 can be changed. In the sintering ignition device, by placing the first ignition furnace as close as possible to the raw material supply device, the length of the rail of the sintering machine can be effectively utilized.

[0022] The variable separation distance D1 in the sintering ignition device is preferably set to a predetermined range including at least a part of the range of 50% to 200% of the distance traveled per minute at the pallet speed. This is because the optimum conditions for high yield or high production rate are found within the separation time range of 0.5 minutes to 2.0 minutes. Here, the pallet speed is the nominal pallet speed, which is the standard operating condition considering the reduced production period and the increased production period.

[0023] Furthermore, the separation distance D1 does not need to be continuously variable, but is configured to be variable at a predetermined interval. In this case, the variable interval (pitch) is preferably set to a distance within a range of 1 / 6 to 1 / 3 of the distance traveled per minute at the pallet speed. This is because the effect of changing the separation distance D1 appears in 10 seconds converted into separation time, but the optimal value cannot be determined unless it is evaluated at 20-second intervals. In other words, it is preferable to set the variable interval (pitch) of the separation distance D1 to an interval corresponding to a separation time of 10 seconds or more and 20 seconds or less so that the yield at each separation distance D1 can be evaluated.

[0024] [Design method of sintering ignition device] The design method of the sintering ignition device of the present invention is a method for designing a sintering ignition device to be installed in a second sintering machine having a pallet width larger than that of the first sintering machine, based on the operation results of a first sintering machine having a sintering ignition device configured to change the separation distance. The sintering ignition device of the second sintering machine is equipped with two ignition furnaces having burner nozzles spaced apart in the strand traveling direction. In the operation of the first sintering machine, the optimal separation time (optimum required time) that maximizes the yield is obtained for the separation time, which is the time required for the pallet to move the separation distance, and the separation distance of the burner nozzle of the sintering ignition device of the second sintering machine is determined based on the pallet speed applied during the operation of the second sintering machine so that the separation time of the sintering ignition device of the second sintering machine is equal to the optimal separation time. The objective variable for optimizing the separation time of the first sintering machine is the yield, but it can also be the production rate. This is because these are important indicators in sintering machine design.

[0025] Here, the first sintering machine is, for example, a small test sintering machine. If it is small, many trials are possible, so the optimum separation distance can be determined with high accuracy. The second sintering machine is, for example, a sintering machine (actual machine) to be designed that has a pallet width larger than that of the first sintering machine, and is equipped with an ignition device having two ignition furnaces, but, for example, the two ignition furnaces have to be fixed, that is, it is a sintering machine in which adjustment of the separation distance is not possible.

[0026] One example is a design method for the case where a sintering machine equipped with two ignition furnaces is newly installed, and the two ignition furnaces of the second sintering machine cannot be configured to be movable due to equipment interference, etc. (hereinafter referred to as a new installation example). Another example is a design method for the case where the second sintering machine is an existing sintering machine and is already equipped with an ignition device having only one ignition furnace (fixed ignition furnace 2), and when attempting to modify this ignition device to an ignition device having another ignition furnace (re-ignition furnace 4) (hereinafter also referred to as a modified ignition device), the re-ignition furnace 4 cannot be configured to be movable due to interference with the existing equipment (hereinafter referred to as a modification example).

[0027] In cases where such a separation distance cannot be made variable, an optimum separation time (optimum required time) is determined in advance using a first sintering machine, which is a sintering machine having a sintering ignition device configured to allow the separation distance to be changed, and the separation distance of the sintering ignition device to be installed in the second sintering machine is determined based on this optimum separation time.

[0028] In the case of the above-mentioned new installation example, it is preferable to make the thickness of the raw material layer of the first sintering machine equal to that of the second sintering machine. If the raw material layer thickness is equal, it is assumed that the separation time of the first sintering machine and the second sintering machine will be equal at the operating point where the yield is best. This is based on the characteristic that the sintering process proceeds one-dimensionally in the height direction, and is independent of the pallet width of the sintering machine. In addition, by assuming that the sintering raw material used in the first sintering machine and the second sintering machine are basically the same, the effect of the raw material layer packing density can also be ignored. Based on these assumptions, for example, the following procedure can be adopted. The order can be changed as appropriate.

[0029] (1-1) A nominal layer thickness, which is the maximum value of the raw material layer thickness of the second sintering machine under standard operating conditions, and a nominal pallet speed, which is the standard operating conditions of the pallet speed of the second sintering machine, are determined. (1-2) By manipulating the separation distance of the first sintering machine at the nominal layer thickness and nominal pallet speed determined in (1-1), the separation distance that maximizes the yield is determined, and the corresponding optimal separation time (optimum required time) is obtained. In this optimization, the heat quantity of the ignition furnace and re-ignition furnace of the first sintering machine should be set to the standard ignition intensity (Qig) of 20 to 30 (MJ / t-raw material). (1-3) Determine the separation distance of the ignition device of the second sintering machine as the product of the nominal pallet speed of (1-1) and the optimal separation time of (1-2) so that the separation time of the ignition device of the second sintering machine is equal to the optimal separation time obtained using the first sintering machine in (1-2).

[0030] In the case of the above-mentioned modification example, it is preferable to match the ignition strength (Qig) and raw material layer thickness of the ignition device after modification to the ignition strength of the ignition device of the second sintering machine when it was operating with only one ignition furnace (hereinafter also referred to as single-unit ignition operation). The raw material layer thickness is as described above, and the ignition strength is for making the input heat amount per unit raw material the same even if the pallet speed is different. Based on this premise, for example, the following procedure can be adopted. Note that the order can be changed as appropriate.

[0031] (2-1) The thickness of the raw material layer in the first sintering machine is made to match the thickness of the raw material layer in the second sintering machine. (2-2) The combustion heat quantity per unit time and the pallet speed of the first sintering machine are set so that the ignition strength of the second sintering machine (the sum of the ignition strength of the ignition furnace and the ignition strength of the re-ignition furnace) matches the ignition strength of the first sintering machine. Note that the pallet speed and the combustion heat quantity per unit time of the first sintering machine do not need to be set to match the pallet speed and the combustion heat quantity per unit time of the second sintering machine, and may be set based on the above-described formulas (2) and (3). (2-3) At the pallet speed and combustion heat amount set in (2-2), the first sintering machine is operated while changing the separation distance, and the optimum separation distance that maximizes the yield is obtained, and the optimum separation time (optimum required time) is obtained, which is the product of the pallet speed and the optimum separation distance set in (2-2). Here, the separation distance is discontinuously changed at a pitch that causes a change in the yield. (2-4) Determine the pallet speed of the second sintering machine, and determine the separation distance of the second sintering machine so that it coincides with the optimal separation time obtained in (2-3). Here, the pallet speed of the second sintering machine may be, for example, a pallet speed determined based on the operation results when one sintering machine was in operation, or the nominal pallet speed of the second sintering machine may be used. EXAMPLES

[0032] Hereinafter, a test sintering machine, which is an example of a first sintering machine equipped with a sintering ignition device of the present invention, will be described with reference to the drawings.

[0033] (Test sintering machine) FIG. 2 is an overall schematic diagram of a test sintering machine. This sintering machine is a sintering machine in which the ignition device of the present invention is applied instead of one ignition furnace in the sintering machine (JP Patent Publication No. 2018-48383). In addition, this test sintering machine is a small sintering machine with a smaller pallet width than the actual machine. Note that the sintering machine is described in detail in the above-mentioned patent document (JP Patent Publication No. 2018-48383), so here, the parts related to the present invention will be simply explained using the drawings.

[0034] As shown in Fig. 2, this test sintering machine 10 is equipped with a pallet cart group 12 in which multiple box-shaped pallet carts 11 are connected, and a drive cart 13 connected to the rearmost upstream end of the pallet cart group 12 in the machine length direction (rail direction). The pallet cart group 12 is provided so that it can travel back and forth on a rail 15, and its travel speed can be adjusted by the drive cart 13. A hopper 17 (raw material surge tank) having a charging chute 16 is installed in the center of the rail 15 in the machine length direction. An ignition device 20 having an ignition furnace 22 and a re-ignition furnace 24 is installed next to the hopper 17 on the downstream side in the machine length direction, and a rock drill 18 for crushing sintered bodies is installed at the downstream end in the machine length direction. A wind box 19 divided into multiple sections is installed below the downstream part of the rail 15 in the machine length direction, and serves as a mechanism for sucking air downward.

[0035] In the present test sintering machine 10, unlike the sintering pot device, the pallet cart group 12 is moved from the time when the sintering raw materials are filled into the pallet cart 11 until the raw material layer is re-ignited. Specifically, the pallet cart group 12 is moved from the left side to the right side in the drawing at a predetermined speed to fill the raw materials, ignite, and re-ignite. Therefore, the traveling speed of the pallet cart group 12 can be regarded as the pallet speed of the test sintering machine 10. The pallet speed in filling the raw materials and the pallet speed in ignition / re-ignition (ignition and re-ignition) may be different. In this case, the raw material filling and the ignition / re-ignition are performed discontinuously. That is, the raw materials are filled while moving the pallet without operating the ignition furnace or re-ignition furnace, and then the front end of the pallet is moved to the entrance of the ignition furnace, and the ignition furnace and re-ignition furnace are operated to ignite and re-ignite the pallet. This pallet speed can be set to any speed between 500mm / min and 4000mm / min, and during ignition and re-ignition, the speed ranges from 500mm / min to 1500mm / min, which roughly corresponds to the actual machine. From the above, the test sintering machine 10 can simulate the packing density of the sintering raw material and the progress of the sintering reaction after ignition and re-ignition more accurately than a batch-type sintering pot apparatus (POT type).

[0036] (Sintering ignition device) FIG. 3 is a schematic diagram of the sintering ignition device 20 of the present invention applied to the test sintering machine 10 of FIG. 2, showing the state in which the ignition furnace 22 and the re-ignition furnace 24 are disposed at the furthest distance from each other. As shown in FIG. 3, the sintering ignition device 20 includes a first ignition furnace 22 for ignition, a second re-ignition furnace 24 for re-ignition, and a frame 26 for supporting them. The length of both ignition furnaces 22, 24 in the machine length direction is 800 mm, the ignition furnace 22 is fixed to the frame 26, and the re-ignition furnace 24 is provided on the frame 26 so as to be slidable in the machine length direction. In addition, the distance L between both ignition furnaces 22, 24 is 0 mm at minimum and 800 mm at maximum due to the movement of the re-ignition furnace 24. The burner nozzle has a double-tube structure. Then, LPG is supplied from the inner tube and air is supplied from the outer tube, and the amount of air that exceeds the amount required for combustion is supplied. Therefore, even if the distance L is 0 mm, this excess air is sucked into the sintered layer from the space downstream of the frame of the ignition furnace 22 and upstream of the frame of the re-ignition furnace 24. Although not shown in the figure, the re-ignition furnace 24 is configured so that it can be fixed with fixing members (bolts) in through holes provided at a pitch of 100 mm, and the multiple nozzle holes of the burner nozzle are provided at approximately equal intervals in the width direction of the pallet.

[0037] The burner nozzles 22a, 24a of each ignition furnace 22, 24 are disposed at the center position in the machine length direction of each ignition furnace 22, 24. Therefore, in the test sintering machine, the separation distance D1 between the burner nozzles of both ignition furnaces 22, 24 can be changed in 100 mm increments from 800 mm to 1600 mm. By making the separation distance variable in this way, test operation can be performed by changing the separation time from ignition to re-ignition of the raw material layer, and the optimum separation time (optimum required time) that maximizes the production rate or yield can be obtained.

[0038] The gaseous fuel used for ignition and re-ignition is, for example, LPG (100 MJ / m 3 The combustion heat (amount of fuel) is adjusted to 3 to 10 m by changing the opening of the gas fuel flow control valve so that it can be matched with the ignition strength (ignition heat per 1 ton of raw material) in the actual machine. 3 It can be adjusted in the range of / h.

[0039] (Design method of sintering ignition device) An example of a modification is given below. Test operations were conducted using the above-mentioned test sintering machine 10 as the first sintering machine having the sintering ignition device of the present invention, which is configured so that the distance can be changed, and based on the results of the operation, the distance between the sintering ignition devices of the second sintering machines (two actual machines: Plant A and Plant B), which have a larger pallet width than the first sintering machine, was determined.

[0040] For Plant A and Plant B, the raw material layer thickness H and ignition strength (ignition strength Qig per ton of raw material) applied during operation are set to the following values ​​as prerequisites. Operating conditions of Plant A: Ignition intensity Qig=20MJ / t-raw material, H=0.50m, Pallet width w=3.5m, charging density ρ=1.70t / m 3 Operating conditions of Plant B: Ignition intensity Qig=22MJ / t-raw material, H=0.70m, Pallet width w=5.5m, charging density ρ=1.75t / m 3

[0041] In this example, the conditions of the test sintering machine were determined as follows. The pallet width w of the test sintering machine was 0.4 m, and the charging density was matched by using the same raw materials as Plant A and B. The burner's combustion heat per unit time Qco (J / min) was set to only 8.3 MJ / min (500 MJ / h). This is because in this embodiment, as described later, the maximum value (peak value) of the product yield was confirmed within the range in which the separation distance can be changed. Note that, by changing the combustion heat Qco (J / min), the changeable range of the separation time T1 can be expanded. In other words, if the combustion heat Qco (J / min) of the test sintering machine is multiplied by a, the pallet speed vp becomes 1 / a times (because the ignition strength Qig (MJ / t-raw material) matches Plant A and B), and the separation time T1 at each separation distance D1 (800 to 1600 mm in [Table 1]) becomes a times (because it is inversely proportional to the pallet speed vp). The raw material layer thickness H and ignition strength Qig of the test sintering machine are the same as the operating conditions of Plant A or Plant B (see (2-1) and (2-2) above). Based on the above and equations (2) and (3), the pallet speed vp of the test sintering machine corresponding to each Plant A and B is 1200 mm / min and 800 mm / min, respectively.

[0042] At the pallet speed determined in the previous paragraph, the test operation was carried out by varying the variable separation distance range of the test sintering machine in 200 mm increments.

[0043] [Table 1]

[0044] The results are shown in Table 1. The optimum separation time (optimum required time) that maximizes the product yield was obtained as 1.17 minutes (70 seconds) for Plant A and 1.50 minutes (90 seconds) for Plant B. Since the nominal pallet speeds of Plant A and Plant B are 2.56 m / min and 3.00 m / min, respectively, the separation distances of the sintering ignition devices in Plant A and Plant B were determined to be 3.0 m and 4.5 m, respectively.

[0045] The above results were reflected in the design of two actual sintering ignition devices. Re-ignition furnaces were installed at the determined distance in Plant A and Plant B. In operation with re-ignition sintering technology, which uses both the existing re-ignition furnace and the newly added re-ignition furnace, the yield increased by 1.7% in Plant A and 2.0% in Plant B while maintaining the same production rate, compared to when re-ignition was not performed. [Explanation of symbols]

[0046] Reference Signs List 1...raw material packed bed, 2, 22...ignition furnace (first ignition furnace), 3...air suction zone, 4, 24...re-ignition furnace (second ignition furnace), 5...combustion zone, 6...sintering completion layer, 7, 17...hopper, 8...combustion front, D1...distance between burner nozzles of both ignition furnaces (separation distance), 10...test sintering machine (first sintering machine), 11...pallet cart, 12...group of pallet carts, 13...drive cart, 15...rail, 16...charging chute, 18...rock drill, 19...wind box, 20...sintering ignition device, 26...frame

Claims

1. A sintering ignition device for use in a sintering machine, comprising: The sintering ignition device has two ignition furnaces spaced apart from each other in the strand traveling direction, A distance between a burner nozzle of a first ignition furnace on the upstream side in the strand traveling direction and a burner nozzle of a second ignition furnace on the downstream side in the strand traveling direction is configured to be discontinuously changeable, 2. A sintering ignition device, comprising: an ignition intensity (ignition heat amount per ton of raw material) of the burner of the first ignition furnace and an ignition intensity of the burner of the second ignition furnace that are configured to be adjustable.

2. a burner nozzle of the first ignition furnace is fixed relative to the sintering machine; 2. The sintering ignition device according to claim 1, wherein the burner nozzle of the second ignition furnace is provided movably relative to the sintering machine.

3. A method for designing a sintering ignition device of a second sintering machine having a pallet width larger than that of a first sintering machine having the sintering ignition device according to claim 1 or 2, comprising: The sintering ignition device of the second sintering machine includes two ignition furnaces having burner nozzles spaced apart from each other in the strand traveling direction, determining an optimal required time for the pallet to move the separation distance during operation of the first sintering machine, which maximizes yield; A method for designing a sintering ignition device, characterized in that a separation distance of a burner nozzle of the sintering ignition device of the second sintering machine is determined based on a pallet speed applied during operation of the second sintering machine so that the time required for the pallet to move the separation distance in the sintering ignition device of the second sintering machine is equal to the optimal required time.

4. 4. An ignition device for sintering, designed based on the design method for an ignition device for sintering according to claim 3.

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