JPS6243111B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an ignition device for a sintering ignition furnace. The sintering machine burns fuel in an ignition furnace, ignites the surface of the raw material layer containing coke with the generated high-temperature gas, and advances sintering by sucking air with a blower through a wind box. If the ignition temperature on the surface of the raw material layer in this ignition furnace is too high, the surface will melt and air permeability will be inhibited, and if it is too low, ignition will be insufficient, both of which will impede the progress of sintering and improve the quality of sintered ore. It causes sexual deterioration. A conventional ignition furnace has several multi-type burners 2 lined up in the width direction of the ignition furnace 1 as shown in the front cross-sectional view of FIG. The raw materials were ignited using combustion gas such as COG. In addition, 3 in the figure is the raw material layer, 4
is a wind box. However, such a multi-burner ignition system has the following drawbacks. 1 In recent years, large-scale sintering machines have a combustion capacity of approximately 500,000 to 1,000,000 Kcal/H per ignition furnace burner.
The combustion gas is blown into the furnace at high speed, resulting in a long combustion flame. For this reason,
In order to efficiently complete combustion of the combustion gas, the distance h between the combustion gas discharge port and the raw material surface must be increased to approximately 800 to 1500 mm, as shown in Figure 2b, so the height of the furnace must be increased. However, it requires a large amount of construction cost. Furthermore, even if the aim is to shorten the flame as shown in Figure 2a, it is extremely difficult to control the flame length to 500 mm or less; for example, if the combustion exhaust gas discharge port is made large in diameter, the burner interval must be lengthened. This makes it difficult to supply the required amount of heat. 2. The temperature distribution on the surface of the raw material directly under the burner in the furnace width direction is shown in the plan view of Fig. 3a and the front sectional view of Fig. 3b, and the temperature deviation is usually about 300°C. For this reason, the surface of the raw material immediately below the center of the burner becomes overmelted and air permeability deteriorates, and the surface of the raw material that is not directly hit by the combustion gas becomes unignited or insufficiently ignited. As a result, uniform sintering cannot be performed, and the temperature distribution of the sintered layer in the ore discharge area remains as an uneven red zone 9 as shown in the front cross-sectional view of Fig. 3c, which deteriorates the quality and productivity of the sintered ore. It was hindering improvement. In addition, in the figure, 10 is a sintered completed part. As a means to alleviate the disadvantage of uneven ignition caused by multi-type burners as described above, burners may be arranged in a staggered manner as shown in Figure 4 (plan view), or
Ignition methods have also been adopted in which a large amount of combustion gas is blown into a structure in which the distance between the combustion gas discharge port and the raw material surface is long, as shown in Figure c, and radiation/convection heat transfer is used. The unit is
When COG is used, it reaches about 5 to 6 Nm ³ /T-product, which has the drawback of requiring a large amount of fuel. The present invention has been made for the purpose of solving the above-mentioned drawbacks of the conventional method and providing a sintered ignition device that is inexpensive to construct, has low fuel consumption, and can produce sintered ore of high quality. That is, in the present invention, the ignition part of the combustion ignition furnace is formed by a single mixing combustion chamber that extends in the furnace width direction and the sintering gas discharge port is narrowed in a slit shape, and the mixing combustion chamber is further extended in the furnace length direction. This sintered ignition device is characterized in that at least one row of sintered ignition devices are arranged in the ignition device. The present invention will be explained below based on examples. First, the present inventors studied the relationship between furnace height and fuel consumption in conventional ignition furnaces, and found that the distance between the combustion gas discharge port and the raw material surface changes as the furnace height h decreases, as shown in Figure 5. It has been found that reducing the amount of heat and, therefore, bringing the combustion gas discharge port closer to the surface of the raw material can greatly contribute to reducing the fuel consumption rate. As a result of intensive research based on such knowledge, the present invention as shown in the embodiments shown in FIGS. 6 to 8 was completed. In Fig. 6, a is a front sectional view, b is a side sectional view, c is a sectional view taken along the line X-X of a, and d is a Y-
It is a sectional view taken along the Y arrow. As shown in FIG. 6 above, in the ignition device, a large number of fuel supply pipes 5 and air supply pipes 6 communicate with one mixed fuel chamber 7 extending in the width direction of the furnace.
The internal space is large, and the gas discharge port 8 is narrowed in the shape of a slit. In the present invention, such ignition devices are arranged in at least one row in the furnace length direction as shown in FIG. 6b. Since the present invention has such a configuration, combustion gas such as COG and air are rapidly mixed and combusted in the mixing combustion chamber with a wide internal space, and when the combustion gas is injected from the discharge port 8, the reaction has reached the final stage. This allows the combustion flame to be short. Therefore, the distance between the discharge port 8 and the surface of the raw material 3 is approximately
Since it can be shortened to 300 to 500 mm, it is possible to reduce equipment costs by shortening the height of the ignition furnace to about 1/3 of the conventional height, and it also reduces heat radiation and cold air entrainment due to gas radiation between the discharge port and the raw material surface. This makes it possible to minimize the temperature drop caused by this, and to achieve highly efficient ignition with a small amount of fuel, which is consistent with the findings shown in FIG. In addition, by narrowing the discharge port 8 into a slit shape, the band-shaped combustion gas quickly and uniformly reaches the surface of the raw material, so that the temperature distribution on the surface of the raw material directly under the burner is distributed in the width direction of the furnace as shown in the plan view of Fig. 7a. The temperature becomes uniform, and the temperature deviation can be suppressed to within about 100°C, as shown in the front sectional view of Figure b. the result,
The temperature distribution of the sintered layer in the ore discharge section is as shown in the front cross-sectional view of Figure c, because the descent of the red zone 9 is smooth and a uniform distribution is obtained, so the sintered ore is cooled well in the latter half of the strand and is uniform. Moreover, an efficient sintering completion state can be obtained, and the product yield and cold strength can be improved. Although the ignition device of the present invention can be implemented using one mixing combustion chamber, it is more appropriate to arrange a plurality of mixing combustion chambers in the furnace length direction for the following reasons. In other words, one method is to control multiple ignitions by changing the ignition conditions for the front and rear rows depending on the operating conditions such as the blending ratio and distribution of the charging raw materials (segregated charging in upper and lower layers, etc.), layer thickness, and sintering speed. This is because the optimum ignition conditions can be selected by appropriately controlling the device array, and also because, for example, even if one ignition device breaks down, it can be repaired while continuing operation with the ignition devices in the other row. As another embodiment of the present invention, in the case of a sintering machine with a wide furnace width, the mixing combustion chamber is divided into two or more chambers as shown in FIG.
It may be divided into about 5 blocks. By dividing the furnace in this way, the amount of fuel gas and air can be controlled by flow rate adjustment valves for each block, which is effective for measures such as increasing the amount of fuel supplied to the ends of the furnace width, which tend to be at low temperatures. Further, if a part of the combustion chamber 7 is damaged, it can be repaired or replaced in units of blocks, and it is also effective in suppressing deformation of refractories such as burner tiles due to thermal expansion and contraction when the ignition furnace is started and stopped. Other effects are the same as when using a mixing combustion chamber that is not divided into blocks. Next, Table 1 shows a comparison of the structure and effects of the implementation results of the present invention and a conventional ignition device. In this embodiment, the present invention uses a single mixing combustion chamber that covers the furnace width and is arranged in two rows in the furnace length direction. Further, the blending ratio of charging raw materials, charging distribution, particle size, etc. were both conducted under the same conditions.

[Table] As is clear from the comparison in Table 1, the following various effects can be obtained by applying the present invention. By shortening the furnace height, the furnace volume can be reduced to about two-fifths of that of the conventional method (staggered arrangement of burners), resulting in reduced construction costs and superior maintainability. Compared to the conventional method, product yield (approximately 5% increase) and cold drop strength (approximately 3% increase) are improved, while ignition furnace fuel consumption rate (approximately 50% decrease) and air volume consumption rate (approx.
100Nm ³ /T-sinter reduction), which brings great benefits in terms of the quality of sintered products and fuel costs.

[Brief explanation of the drawing]

Figures 1 to 4 show examples of conventional ignition devices, where Figure 1a is a front sectional view, b is a side sectional view, and Figure 2a is a side sectional view.
~c is a front cross-sectional view showing the ignition state, Figures a and b are a plan view and front cross-sectional view showing the raw material surface temperature distribution directly under the burner, and Figure c is a front cross-section showing the completed sintering state of the ore discharge section. FIG. 4 is a plan sectional view showing an example of burner arrangement. Fig. 5 to Fig. 8 show examples of the present invention, Fig. 5 is a diagram showing the relationship between furnace height and combustion amount, Fig. 6 a is a front sectional view, b is a side sectional view, and c
is a cross-sectional view taken along the line X-X of a, and d is a cross-sectional view taken along the line Y-Y of a. Figure 7 a and b are a plan view and a front sectional view showing the temperature distribution on the surface of the raw material directly under the burner, and figure c
8 is a front sectional view showing a completed state of sintering of the ore discharge section, and FIG. 8 is a top sectional view of the outlet of the mixing combustion chamber showing another embodiment of the present invention. In the figure, 1... ignition furnace, 2... burner,
3... Raw material layer, 4... Wind box, 5...
Fuel supply pipe, 6...Air supply pipe, 7...Mixing combustion chamber, 8...Combustion gas discharge port, 9...Red tropical, 10
...The sintered part.

Claims (1)

[Claims] 1 The ignition part of the sintering ignition furnace is formed by a single mixing combustion chamber extending in the width direction of the furnace and having a narrowed sintering gas discharge port in the form of a slit, and the mixing combustion chamber is further formed with at least one mixing combustion chamber extending in the furnace length direction. A sintered igniter characterized by being arranged in rows.