JP7568174B1 - Sintered ore manufacturing apparatus, sintered ore manufacturing method, and program - Google Patents

Abstract

[Problem] To provide a sintered ore manufacturing apparatus capable of suppressing uneven sintering of charged raw materials. [Solution] The sintered ore manufacturing apparatus is a Dwight Lloyd type sintered ore manufacturing apparatus. The sintered ore manufacturing apparatus has a pallet that moves in a circulating manner and on which a raw material layer of sintered ore raw materials is formed, an ignition furnace that sinters the raw material layer on the pallet with a line burner, and an ore discharge section that is located downstream of the ignition furnace and discharges the sintered raw material layer. The sintered ore manufacturing apparatus has a sintering amount data generating section that generates sintering amount data that is the sintering amount of the raw material layer based on a first layer thickness that is the layer thickness of the raw material layer leveled by a cut gate located upstream of the sintering machine and a second layer thickness that is the layer thickness of the raw material layer at the ore discharge section, and a gas amount adjusting section that adjusts the amount of combustion gas supplied to the line burner of the sintering machine based on the sintering amount data.

Description

The present invention relates to a Dwight Lloyd type sintered ore manufacturing apparatus, a sintered ore manufacturing method, and a program.

Sintered ore, which is a raw material for blast furnaces, mainly contains iron ore, limestone and quicklime, auxiliary materials containing _SiO2 -based components, return ore, and solid fuels such as coke powder. Sintered ore is produced as follows. After moisture is added to the raw materials, the raw materials are granulated to form pseudo-particles. The pseudo-particles are charged into a pallet. The pseudo-particles charged into the pallet are called the charged raw material.

The pallets move in a circulating manner within the sintering machine. The height of the raw materials is adjusted by passing through a cut gate installed in the sintering machine. After passing through the cut gate, the solid fuel contained in the raw materials is burned and the sintered ore is produced. The combustion of the sintered ore is completed in the discharge section where crushing takes place. The crushed sintered ore is cooled and then straightened.

From the viewpoint of ensuring the strength of the sintered ore and improving yield, it is preferable that the raw materials are fired evenly across the width of the pallet. Therefore, measures have been taken to prevent uneven sintering of the raw materials. For example, Patent Document 1 discloses adjusting the height of the raw materials across the width of the pallet depending on the combustion state of the raw materials across the width of the pallet.

Patent document 2 also discloses measuring the wind speed passing through the sintered layer at multiple positions across the width of the sintering machine, and adjusting the amount of raw material supplied across the width of the sintering machine depending on the wind speed.

JP 2017-57481 A Japanese Patent Application Publication No. 61-250120

However, the method described in Patent Document 1 requires the raw material layer loaded on the pallet to be imaged from the front, which limits the position where the camera can be placed. In addition, since the image is taken when the raw material falls into the ore discharge section, it is difficult to obtain a clear image, which causes a problem of variation in measurement accuracy. For this reason, Patent Document 1 has the problem that adjustments to improve yield cannot be quickly implemented.

Incidentally, uneven sintering can be caused by uneven surface temperature after the raw material layer is ignited. It is believed that uneven surface temperature of the raw material layer is caused by uneven distribution of coke contained in the raw material as solid fuel. In Patent Document 2, the uneven distribution of coke cannot be adjusted, and therefore there is a problem in that uneven sintering cannot be improved.

The present invention has been made in consideration of the above-mentioned problems, and aims to provide a sintered ore manufacturing apparatus, a sintered ore manufacturing method, and a program that can prevent uneven sintering of charged raw materials.

In order to solve the above problems, the present invention has the following features.
[1]
A Dwight Lloyd type sintered ore manufacturing apparatus having a pallet that moves in a circulating manner and on which a layer of raw material for sintered ore is formed, an ignition furnace that sinters the raw material layer on the pallet with a line burner, and a discharge section that is located downstream of the ignition furnace and discharges the sintered raw material layer,
a shrinkage amount data generating unit that generates shrinkage amount data, which is a shrinkage amount of the raw material layer, based on a first layer thickness, which is a layer thickness of the raw material layer leveled by a cut gate located upstream of the ignition furnace, and a second layer thickness, which is a layer thickness of the raw material layer in the ore discharge section;
a gas amount adjusting unit that adjusts the amount of combustion gas supplied to the line burner of the ignition furnace based on the sintering amount data;
The sintered ore manufacturing apparatus has the following features.
[2]
The sintering amount data generating unit generates the sintering amount data for a plurality of different locations in a width direction of the pallet.
[3]
The sintering amount data generating unit generates the sintering amount data for five locations equally spaced apart in the width direction of the pallet.
[4]
The line burner of the ignition furnace heats a plurality of different regions in a width direction of the pallet,
The sintering amount data generating unit generates the sintering amount data at a location corresponding to a heating region of the line burner.
[5]
The line burner of the ignition furnace heats a central region in a width direction of the pallet and other regions disposed on both sides of the central region in the width direction of the pallet,
The sintered ore manufacturing apparatus according to claim 2, wherein the gas amount adjusting unit adjusts the amount of the combustion gas supplied to the central region to be less than that supplied to the other regions.
[6]
A surface temperature acquisition unit is provided for acquiring a surface temperature of the raw material layer when the raw material layer is ignited in the ignition furnace and a target value of the surface temperature determined based on the sintering amount,
The gas amount adjustment unit adjusts the amount of combustion gas supplied to the line burner of the ignition furnace based on the surface temperature of the raw material bed and the target value of the surface temperature.
[7]
A method for producing sintered ore using a Dwight Lloyd type sintered ore production apparatus having a pallet that moves in a circulating manner and on which a layer of raw material for sintered ore is formed, an ignition furnace that sinters the raw material layer on the pallet with a line burner, and a discharge section that is located downstream of the ignition furnace and discharges the sintered raw material layer,
a shrinkage amount data generating step of generating shrinkage amount data, which is a shrinkage amount of the raw material layer, based on a first layer thickness, which is a layer thickness of the raw material layer leveled by a cut gate located upstream of the ignition furnace, and a second layer thickness, which is a layer thickness of the raw material layer at the ore discharge section;
A gas amount adjusting process for adjusting the amount of combustion gas supplied to the line burner of the ignition furnace based on the shrinkage amount data generated in the shrinkage amount data generating process;
The method for producing sintered ore comprises the steps of:
[8]
A computer controls the operation of a Dwight Lloyd type sintered ore manufacturing apparatus having a pallet that moves in a circulating manner and on which a layer of raw material for sintered ore is formed, an ignition furnace that sinters the raw material layer on the pallet with a line burner, and a discharge section that is located downstream of the ignition furnace and discharges the sintered raw material layer,
a shrinkage amount data generating step of generating shrinkage amount data, which is a shrinkage amount of the raw material layer, based on a first layer thickness, which is a layer thickness of the raw material layer leveled by a cut gate located upstream of the ignition furnace, and a second layer thickness, which is a layer thickness of the raw material layer at the ore discharge section;
A gas amount adjusting process for adjusting the amount of combustion gas supplied to the line burner of the ignition furnace based on the shrinkage amount data generated in the shrinkage amount data generating process;
A program that executes the following.

According to the sintered ore manufacturing method and sintered ore manufacturing device of the present invention, the amount of combustion gas supplied to the line burner of the ignition furnace is adjusted based on the amount of sintering of the raw material layer. This makes it possible to adjust the amount of sintering of the raw material layer to an appropriate state. Therefore, it is possible to reduce variation in the sintering of the raw material layer and improve the yield of sintered ore.

FIG. 1 is an explanatory diagram showing an overview of a sintered ore manufacturing apparatus. FIG. 2 is an explanatory diagram showing the configuration of a sintered ore manufacturing apparatus as viewed from above. FIG. 2 is a block diagram showing functional blocks of a sintered ore manufacturing apparatus. FIG. 2 is a flow diagram showing a process flow of a method for producing sintered ore. FIG. 5 is a flowchart showing a subroutine of a gas amount adjustment step in FIG. 4 . 4 is a graph showing the supply amount of combustion gas of each line burner. 4 is a graph showing the surface temperature in each region of the raw material layer. 1 is a graph showing the amount of densification in each region of a raw material layer. 1 is a graph showing the amount of return ore generated. 1 is a graph showing the relationship between the amount of sintering and the amount of return ore generated.

Below, an embodiment of the present invention will be described with reference to the drawings. Figure 1 shows an overview of a sintered ore manufacturing apparatus. The sintered ore manufacturing apparatus 100 is a so-called Dwight Lloyd type manufacturing apparatus. The sintered ore manufacturing apparatus 100 has a surge hopper 10 that stores the raw material 20 for sintered ore.

The raw material 20 for the sintered ore is not particularly limited, but examples thereof include iron-containing raw materials including various iron ores such as hematite and magnetite, CaO-containing raw materials including limestone and quicklime, MgO-containing raw materials including dolomite and refined nickel slag, and powdered coke as a solid fuel. The iron-containing raw materials may include dust generated in the steelworks, which is blown up in the steelworks. The raw material for the sintered ore may also include return ore, which is fine sintered ore that does not meet the specified size.

The surge hopper 10 stores the raw material 20 in the form of pseudo-particles granulated by mixing the raw material with water. The surge hopper 10 has a roll feeder 11 that cuts out and discharges a predetermined amount of the stored raw material 20. The raw material 20 discharged from the roll feeder 11 is divided into a predetermined direction by a dividing gate 12 and then loaded onto a pallet 30.

The pallet 30 is a conveying device that conveys raw materials in one direction (hereinafter also referred to as the conveying direction) D1. The pallet 30 is configured, for example, to be capable of circular movement.

A cut gate 40 is provided downstream of the pallet 30 in the conveying direction D1. The cut gate 40 has an opening formed at a constant height in the width direction of the pallet 30. The height of the opening of the cut gate 40 is set lower than the height of the raw material (hereinafter also referred to as the raw material layer) 21 loaded on the pallet 30 located upstream of it. Therefore, when the pallet 30 passes through the cut gate 40, the height of the raw material layer 21 is leveled.

In the conveying direction D1 of the pallet 30, an ignition furnace 50 is provided downstream of the cut gate 40. The ignition furnace 50 is provided above the pallet 30. The ignition furnace 50 is configured to be able to supply combustible gas (hereinafter also referred to as combustion gas) toward the raw material layer 21 of the pallet 30. In addition, a wind box (not shown) is provided below the ignition furnace 50. The wind box is provided below the pallet 30 and draws in air so that air flows from above the pallet 30 to below.

In the conveying direction D1 of the pallet 30, a surface thermometer 60 is provided downstream of the ignition furnace 50. The surface thermometer 60 is a thermometer that measures the surface temperature of the sintered raw material 22. The surface thermometer 60 is not particularly limited, but may be, for example, a thermo camera.

In the conveying direction D1 of the pallet 30, a layer thickness level meter 70 is provided downstream of the surface thermometer 60. The layer thickness level meter 70 is a sensor that measures the height of the raw material layer 21 burned in the ignition furnace 50. The layer thickness level meter 70 is not particularly limited, but may be, for example, an ultrasonic distance meter, a laser distance meter, or the like.

In the conveying direction D1 of the pallet 30, downstream of the layer thickness level gauge 70, there is provided an ore discharge section 80 for discharging the sintered raw material layer 21. In the ore discharge section 80, the combustion of the raw material layer 21 is completed. The raw material layer 21, which is baked by the heat of combustion, becomes a lump-shaped sintered cake. The sintered cake is discharged to the outside from the ore discharge section 80. When the sintered cake falls from the pallet 30 in the ore discharge section 80, it cracks in the width direction of the conveying direction D1 and breaks. The sintered cake discharged from the ore discharge section 80 is crushed and then cooled. The cooled sintered cake is granulated to become a product sintered ore consisting of agglomerates with an average particle size of 5.0 mm or more. Note that sintered ore with an average particle size of less than 5.0 mm is not suitable for charging into a blast furnace and is used again as a raw material for sintered ore.

The sintered ore manufacturing apparatus 100 has a control unit 90 that controls the operation of the apparatus. The control unit 90 has a shrinkage amount data generation unit 91 that generates shrinkage amount data, which is the shrinkage amount of the raw material layer 21. The control unit 90 has a gas amount adjustment unit 92 that adjusts the amount of combustion gas supplied to the ignition furnace 50 based on the shrinkage amount data. The control unit 90 has a surface temperature acquisition unit 93 that acquires the surface temperature of the raw material layer 21 and a target value for the surface temperature of the raw material layer 21.

Figure 2 shows the configuration of the sintered ore manufacturing apparatus 100 as viewed from above. As shown in Figure 2, the ignition furnace 50 has a plurality of line burners 51 arranged in a width direction D2 in the conveying direction D1. Note that the direction D2 corresponds to the width direction of the pallet 30.

2, six line burners 51 are arranged at predetermined intervals in the width direction D2. Each line burner 51 is arranged so as to be able to eject combustion gas toward the raw material layer 21 of the pallet 30. Each line burner 51 also has a valve (not shown) that can independently adjust the amount of ejected combustion gas. In this way, each of the line burners 51 is preferably arranged so as to heat a plurality of different regions in the width direction D2 of the pallet 30.

The layer thickness level gauges 70 are arranged at a predetermined interval in the width direction D2. In FIG. 2, five layer thickness level gauges 70 are arranged in the width direction D2. The number of layer thickness level gauges 70 is not particularly limited, but can be provided according to the detection area of the layer thickness level gauge 70 and the length of the width direction D2 of the pallet 30. It is preferable that each layer thickness level gauge 70 is provided, for example, five at equal intervals. In addition, the layer thickness level gauge 70 can be installed at any position downstream of the ignition furnace 50 in the conveying direction D1. In addition, each layer thickness level gauge 70 is preferably provided at a position corresponding to the heating area of the line burner 51.

Figure 3 shows the functional blocks of the sintered ore manufacturing apparatus 100. As shown in Figure 3, the sintered ore manufacturing apparatus 100 includes an ignition furnace 50, a surface thermometer 60, a layer thickness level gauge 70, and a control unit 90, which are connected to each other via a bus B so that they can communicate with each other.

The control unit 90 is a computer that controls the operation of the sintered ore manufacturing apparatus 100, which has a CPU, ROM, and RAM. The control unit 90 reads the necessary data and software programs from the ROM, and performs calculations on the data in accordance with the software programs.

The ROM stores a first layer thickness, which is the layer thickness of the raw material layer 21 leveled by the cut gate 40. The first layer thickness may be the height of the opening of the cut gate 40, or may be measured using a layer thickness level meter (not shown). The ROM also stores a target value for the amount of shrinkage, a target value for the amount of combustion gas supplied according to the target value for the amount of shrinkage, and a target value for the surface temperature of the raw material layer 21 when the raw material layer 21 is ignited in the ignition furnace 50.

The surface thermometer 60 is installed facing the raw material layer 21. When the surface thermometer 60 starts measuring the temperature, it sequentially stores the measured temperature in the ROM of the control unit 90 as the surface temperature of the raw material layer 21.

When each layer thickness level meter 70 measures the layer thickness of the raw material layer 21, it sequentially stores the layer thickness in the ROM of the control unit 90 as a second layer thickness. Each layer thickness level meter 70 sequentially stores the layer thickness of each region corresponding to the heating region of the line burner 51, for example, as the second layer thickness in the ROM of the control unit 90.

The ignition furnace 50 is a device that ejects combustion gas from each line burner 51 based on instructions from the control unit 90.

The shrinkage amount data generation unit 91 of the control unit 90 generates shrinkage amount data, which is the shrinkage amount of the raw material layer 21, based on the first layer thickness and the second layer thickness, which is the layer thickness of the raw material layer 21 in the ore discharge section 80.

The shrinkage amount can be generated as the degree of shrinkage of the raw material layer 21 due to firing. The shrinkage amount data generating unit 91 obtains the shrinkage amount, for example, by subtracting the second layer thickness of the area corresponding to the first layer thickness from the first layer thickness, and generates the shrinkage amount as shrinkage amount data. The shrinkage amount data generating unit 91 stores the generated shrinkage amount data in ROM.

The gas amount adjustment unit 92 adjusts the amount of combustion gas supplied to the ignition furnace 50 based on the shrinkage amount data generated by the shrinkage amount data generation unit 91. The gas amount adjustment unit 92 adjusts the amount of combustion gas supplied to the ignition furnace 50, for example, by adjusting the opening of a valve (not shown) provided in the line burner 51. In addition, the gas amount adjustment unit 92 may independently adjust the opening of a valve (not shown) provided in each line burner 51.

The surface temperature acquisition unit 93 acquires the surface temperature of the raw material layer 21 and the target value of the surface temperature of the raw material layer 21 by referring to the ROM. The target value of the surface temperature of the raw material layer 21 may be determined based on the amount of shrinkage. The target value of the surface temperature of the raw material layer 21 may be determined, for example, by deriving the relationship of the surface temperature corresponding to the amount of shrinkage that is the target value through testing or the like, and by using the surface temperature of the raw material layer 21 that corresponds to the amount of shrinkage.

Figure 4 shows the process flow of the sintered ore manufacturing method. The process flow of the sintered ore manufacturing method is executed, for example, by the operation of the sintered ore manufacturing apparatus 100. As shown in Figure 4, when the process flow of the sintered ore manufacturing method is executed, the sintering amount data generation unit 91 reads the first layer thickness and the second layer thickness from the ROM. The sintering amount data generation unit 91 generates sintering amount data, which is the sintering amount of the raw material layer 21, based on the first layer thickness and the second layer thickness, and executes the sintering amount data generation process (step S101).

In the shrinking amount data generation process of step S101, the shrinking amount data generation unit 91 may generate each shrinking amount data using the first layer thickness, which is the opening height of the cut gate 40, and the second layer thickness measured by each layer thickness level meter 70.

The shrinking amount data generating unit 91 may generate shrinking amount data for a plurality of different locations in the width direction D2 of the pallet 30. Specifically, the shrinking amount data generating unit 91 may generate shrinking amount data for locations corresponding to the heating area of the line burner 51. In this manner, by generating shrinking amount data, it is possible to grasp the bias in the shrinking amount in the width direction D2 of the pallet 30. The shrinking amount data generating unit 91 may generate a target value for the amount of combustion gas supplied to the line burner 51 corresponding to the shrinking amount data.

Next, the surface temperature acquisition unit 93 executes the surface temperature acquisition process by referring to the ROM to acquire the surface temperature of the raw material layer 21 and the target value for the surface temperature of the raw material layer 21 (step S102).

The gas amount adjustment unit 92 performs the gas amount adjustment process by adjusting the amount of combustion gas supplied to the ignition furnace 50 based on the sintering amount data generated in step S101 (step S103).

In the gas amount adjustment process of step S103, the gas amount adjustment unit 92 adjusts the amount of combustion gas supplied to the ignition furnace 50, for example, so that the shrinkage amount data generated in step S101 becomes a predetermined target value. At this time, the gas amount adjustment unit 92 may adjust the amount of combustion gas so as to approach the target value of the surface temperature of the raw material layer 21 acquired in the surface temperature acquisition process of step S102. The surface temperature of the raw material layer 21 is highly related to the shrinkage amount. Therefore, by adjusting the amount of combustion gas using two elements, the shrinkage amount data and the target value of the surface temperature of the raw material layer 21, it is possible to bring the shrinkage amount closer to an appropriate state.

Figure 5 shows a subroutine of the gas amount adjustment process by the gas amount adjustment unit 92. As shown in Figure 5, when the gas amount adjustment process is started, the gas amount adjustment unit 92 acquires the shrinkage amount and the shrinkage amount target value, which is the target value of the shrinkage amount, and executes the shrinkage amount acquisition process (S201).

The gas amount adjustment unit 92 determines whether the difference between the shrinkage amount obtained in step S201 and the target shrinkage amount value is within a threshold value (step S202).

If the determination in step S202 is below the threshold value (step S202: Yes), the gas amount adjustment unit 92 maintains the setting (step S203) and terminates the processing.

If the determination in step S202 is not below the threshold value (step S202: No), the gas amount adjustment unit 92 obtains the amount of combustion gas ejected from each line burner 51 and the target value for the amount of combustion gas ejected from each line burner 51 (step S204).

The gas amount adjustment unit 92 changes the settings so that the amount of ejected combustion gas obtained in step S204 approaches the target value created in step S101 and so that the surface temperature of the raw material layer 21 obtained in step S102 approaches the target value (step S205).

The gas amount adjustment unit 92 returns to the shrinkage amount acquisition process of step S201, and repeats the above process until it is determined in the threshold determination process of step S202 that the amount is equal to or less than the threshold. The gas amount adjustment unit 92 may perform the processes of steps S201 to S205 using so-called PID (Proportional-Integral-Differential) control.

As described above, according to the sintered ore manufacturing apparatus 100 and sintered ore manufacturing method of this embodiment, the amount of combustion gas supplied to the line burners 51 of the ignition furnace 50 is adjusted based on the amount of sintering of the raw material layer 21. This makes it possible to adjust the amount of sintering of the raw material layer 21 to an appropriate state. Furthermore, by adjusting the amount of combustion gas for each of the multiple line burners 51 arranged in the width direction D2 of the pallet 30, it is possible to reduce the variation in sintering in the width direction D2 of the pallet 30, and improve the yield of sintered ore.

In addition, by adjusting the amount of combustion gas supplied to the line burner 51 of the ignition furnace 50 so that the surface temperature of the raw material layer 21 approaches the target value, the amount of sintering of the raw material layer 21 can be adjusted to a more appropriate state.

The amount of sintering is likely to be biased in the width direction D2 of the pallet 30. For example, in the width direction D2 of the pallet 30, the probability of return ore tends to be higher at the end side than at the center side. In such a case, it is advisable to adjust the amount of combustion gas supplied to the center side to be less than that at the end side. Specifically, it is advisable to arrange multiple line burners 51 so as to heat the central region in the width direction D2 of the pallet 30 and other regions arranged on both sides of the central region. In addition, it is advisable to adjust the gas amount adjustment unit 92 to adjust the amount of combustion gas supplied to the central region to be less than that of the other regions.

The surface temperature acquisition process of step S102 is an optional process. Therefore, depending on the embodiment, this process may be omitted. In this case, in the setting change process of step S205, the gas amount adjustment unit 92 may change the setting so that the amount of ejected combustion gas acquired in step S204 approaches the target value created in step S101.

Sintered ore was produced by changing the amount of combustion gas supplied to the line burners of the ignition furnace, and the amount of return ore was compared. Five line burners were arranged at equal intervals across the width of the pallet. A comparative example was performed in which the amount of combustion gas supplied to each line burner was kept constant. An example was performed in which the amount of combustion gas supplied to each line burner was adjusted according to the amount of sintering of the raw material layer.

The amount of combustion gas supplied to each line burner in the comparative example was as follows. Fig. 6 is a graph showing the amount of combustion gas supplied to line burners arranged in the width direction of the pallet. In Fig. 6, line burners 1 to 5 are arranged in order from the ends in the width direction of the pallet. Line burners 1 and 5 are arranged at the ends in the width direction of the pallet. Line burner 3 is arranged in the center in the width direction of the pallet. Line burners 2 and 4 are arranged between line burners 1, 5 and line burner 3 in the width direction of the pallet. As shown in Fig. 6, in the comparative example, the amount of combustion gas supplied to line burners 1 to 5 was 288 Nm ³ /h.

The raw material layer was fired under the conditions shown in Figure 6. The surface temperature of the raw material layer in the comparative example at that time was as follows. Figure 7 is a graph showing the surface temperature of the raw material layer in each region extending in the width direction of the pallet. As shown in Figure 7, in the comparative example, the surface temperature of the raw material layer in the northern region was 270°C. In the central region, the surface temperature of the raw material layer was 252°C. In the southern region, the surface temperature of the raw material layer was 286°C.

The raw material layer was fired under the conditions shown in Figure 6. The amount of shrinkage of the raw material layer in the comparative example was as follows. Figure 8 is a graph showing the amount of shrinkage of the raw material layer in each region extending in the width direction of the pallet. In Figure 8, regions 1 to 5 correspond to the installation positions of line burners 1 to 5. In the comparative example, there was a difference in the amount of shrinkage between the center side and the end sides in the width direction of the pallet 30. Specifically, the amount of shrinkage at the center side in the width direction of the pallet 30 was higher than the other regions.

The raw material layer was fired under the conditions shown in Figure 6. The amount of return ore generated in the comparative example was as follows. Figure 9 is a graph showing the amount of return ore generated per unit time. As shown in Figure 9, the amount of return ore in the comparative example was 149.3 t/h.

Next, the return ore amount in the examples was determined. In the examples, the target value of the shrink amount was set based on the relationship between the shrink amount and the return ore amount. Figure 10 is a graph showing the relationship between the shrink amount and the return ore amount. As shown in Figure 10, there is a tendency for the return ore consumption rate to decrease when the shrink amount is between 50 and 90 mm. Once the shrink amount reaches 90 mm, the return ore consumption rate becomes almost constant thereafter. Therefore, even if the shrink amount is set to a value higher than 90 mm, it becomes difficult to achieve a reduction in the return ore consumption rate. In the examples, the target shrink amount was set to 90 mm.

In the examples, the supply amount of combustion gas was adjusted so that the shrinkage amount obtained in the comparative example was the target shrinkage amount of 90 mm. As an example of adjustment of the supply amount of combustion gas by the gas amount adjustment unit, for example, when the shrinkage amount of region 4 in Fig. 8 is measured to be 50 mm, the gas amount adjustment unit adjusts the supply amount of combustion gas supplied to the line burner that heats the region 4 to be increased to more than 288 ^Nm3 /h. The adjustment of the supply amount of combustion gas is continued until the shrinkage amount becomes 90 mm.

8 is measured to be 130 mm, the gas amount adjusting unit 92 adjusts the supply amount of the combustion gas supplied to the line burner that heats the region 3 to be less than 76 ^Nm3 /h. The adjustment of the supply amount of the combustion gas is continued until the shrinkage amount becomes 90 mm.

As a result of adjusting the amount of combustion gas supplied by the gas amount adjusting unit in this manner, in the example, the amount of combustion gas supplied to line burners 1, 2, 4, and 5 was 341 ^Nm3 /h, as shown in Fig. 6. The amount of combustion gas supplied to line burner 3 was 76 ^Nm3 /h. The amount of combustion gas supplied to line burner 3, which is disposed on the center side in the width direction of the pallet, was ⅓ or less of the amount of combustion gas supplied to line burners 1, 2, 4, and 5, which are disposed on the end sides in the width direction of the pallet.

The raw material layer was fired under the conditions shown in Figure 6. The surface temperatures of the raw material layer in the example were as follows. As shown in Figure 7, in the example, the surface temperature of the raw material layer in the northern region was 280°C. In the central region, the surface temperature of the raw material layer was 103°C. In the southern region, the surface temperature of the raw material layer was 266°C.

The raw material layer was sintered under the conditions shown in Figure 6. The sintering amount of the raw material layer in this example was 90 mm in all regions 1 to 5, as shown in Figure 8.

The raw material layer was fired under the conditions shown in Figure 6. The amount of return ore generated in the example was as follows. Figure 9 is a graph showing the amount of return ore generated per unit time. As shown in Figure 9, the amount of return ore in the example was 141.0 t/h. Therefore, it was found that the amount of return ore in the example was 8.3 t/h lower than that in the comparative example.

In this way, it was found that by reducing the amount of gas in the center of the width of the pallet compared to the other areas, it was possible to suppress bias in the amount of densification. It was found that the raw material layer in the center tends to be sufficiently densified even if the surface temperature is low. It was found that the raw material layers at the edges tend not to be sufficiently densified unless the surface temperature is high.

The gas amount adjustment unit can make the amount of sintering of the raw material layer uniform by adjusting the amount of gas supplied so that the amount of sintering reaches the target value, as in the example. As a result, it was confirmed that the amount of return ore generated was reduced.

In other words, it was found that the amount of return ore generated increases when the firing of the raw material layer is uneven, and decreases as the firing of the raw material layer becomes more uniform (the variation in firing decreases). Furthermore, a decrease in the amount of return ore generated means that a large amount of product sintered ore with a larger particle size is produced after sizing. It was found that in order to uniformly fire the raw material layer, it is effective to uniform the amount of heat in the raw material across the width of the pallet and improve firing unevenness.

Reference Signs List 100 Sintered ore manufacturing apparatus 20 Raw material 21 Raw material layer 30 Pallet 40 Cut gate 50 Ignition furnace 51 Line burner 60 Surface thermometer 70 Layer thickness level meter 80 Ore discharge section 90 Control section 91 Sintering amount data generating section 92 Gas amount adjusting section 93 Surface temperature acquiring section

Claims (8)

A Dwight Lloyd type sintered ore manufacturing apparatus having a pallet that moves in a circulating manner and on which a layer of raw material for sintered ore is formed, an ignition furnace that sinters the raw material layer on the pallet with a line burner, and a discharge section that is located downstream of the ignition furnace and discharges the sintered raw material layer,
a shrinkage amount data generating unit that generates shrinkage amount data, which is a shrinkage amount of the raw material layer, based on a first layer thickness, which is a layer thickness of the raw material layer leveled by a cut gate located upstream of the ignition furnace, and a second layer thickness, which is a layer thickness of the raw material layer in the ore discharge section;
a gas amount adjusting unit that adjusts the amount of combustion gas supplied to the line burner of the ignition furnace based on the sintering amount data;
The sintered ore manufacturing apparatus has the following features. The sintering amount data generating unit generates the sintering amount data for multiple different locations in the width direction of the pallet. The sintering amount data generating unit generates the sintering amount data for five locations equally spaced apart in the width direction of the pallet. The line burner of the ignition furnace heats a plurality of different regions in the width direction of the pallet,
The sintered ore manufacturing apparatus according to claim 2 or 3, wherein the shrinkage amount data generating unit generates the shrinkage amount data for a portion corresponding to a heating region of the line burner. The line burner of the ignition furnace heats a central region in a width direction of the pallet and other regions disposed on both sides of the central region in the width direction of the pallet,
The sintered ore manufacturing apparatus according to claim 2 or 3, wherein the gas amount adjusting unit adjusts the supply amount of the combustion gas in the central region to be less than that in the other regions. A surface temperature acquisition unit is provided for acquiring a surface temperature of the raw material layer when the raw material layer is ignited in the ignition furnace and a target value of the surface temperature determined based on the sintering amount,
The gas amount adjustment unit adjusts the amount of combustion gas supplied to the line burner of the ignition furnace based on the surface temperature of the raw material bed and the target value of the surface temperature. The sintered ore manufacturing apparatus according to any one of claims 1 to 3. A method for producing sintered ore using a Dwight Lloyd type sintered ore production apparatus having a pallet that moves in a circulating manner and on which a layer of raw material for sintered ore is formed, an ignition furnace that sinters the raw material layer on the pallet with a line burner, and a discharge section that is located downstream of the ignition furnace and discharges the sintered raw material layer,
a shrinkage amount data generating step of generating shrinkage amount data, which is a shrinkage amount of the raw material layer, based on a first layer thickness, which is a layer thickness of the raw material layer leveled by a cut gate located upstream of the ignition furnace, and a second layer thickness, which is a layer thickness of the raw material layer at the ore discharge section;
A gas amount adjusting process for adjusting the amount of combustion gas supplied to the line burner of the ignition furnace based on the shrinkage amount data generated in the shrinkage amount data generating process;
The method for producing sintered ore comprises the steps of: A computer controls the operation of a Dwight Lloyd type sintered ore manufacturing apparatus having a pallet that moves in a circulating manner and on which a layer of raw material for sintered ore is formed, an ignition furnace that sinters the raw material layer on the pallet with a line burner, and a discharge section that is located downstream of the ignition furnace and discharges the sintered raw material layer,
a shrinkage amount data generating step of generating shrinkage amount data, which is a shrinkage amount of the raw material layer, based on a first layer thickness, which is a layer thickness of the raw material layer leveled by a cut gate located upstream of the ignition furnace, and a second layer thickness, which is a layer thickness of the raw material layer at the ore discharge section;
A gas amount adjusting process for adjusting the amount of combustion gas supplied to the line burner of the ignition furnace based on the shrinkage amount data generated in the shrinkage amount data generating process;
A program that executes the following.

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