JPS6039129A - Method for igniting starting material for sintering - Google Patents

Abstract

PURPOSE:To reduce the quantity of energy required to ignite starting materials for sintering and to improve the quality and yield of sintered ore by feeding unignited fuel to the surface of a layer of the starting materials on a pallet and by igniting the surface layer of the starting materials. CONSTITUTION:Starting materials 2 for sintering are fed to a sintering pallet 8 from a starting material feeding hopper 4 through an ore feeding shoot 6, and the surface is leveled to form a layer of a prescribed depth. Unignited fuel 18 is fed to the surface of the materials 2 on the pallet 8 with a suitable ignition assisting device 17, and it is uniformly spread. The materials 2 covered with the fuel 18 enter an ignition furnace 10, where the surface layer of the materials 2 is ignited with burners 12 using coke oven gas or the like. Since the fuel is present in the surface layer, the materials 2 are ignited at a relatively low temp. in a short time, and a rapid drop in the temp. of the sintered surface layer is prevented, so the deterioration of the quality of sintered ore is prevented.

Description

[Detailed Description of the Invention] <Object of the Invention> The present invention relates to a method for igniting sintered raw materials, and in particular aims to reduce the energy required for ignition, improve the quality of sintered ore, and improve the yield. shall be.

<Prior Art> A method and apparatus for igniting the surface of a sintered raw material in a conventional Dwight Lloyd type (hereinafter abbreviated as DL type) sintering apparatus will be explained with reference to FIG. The sintering raw material 2 is supplied from -sintering raw material feeding hopper-4,
The raw material is charged into the sintering millet 8 through the raw material chute 6, and the surface is smoothed to a predetermined depth. Next, the noglet 8 charged with the sintering raw material 2 is ignited into an ignition furnace 10 adjacent to the sintering raw material feed hopper 2. The ignition furnace 10 generally has a steel frame lined with a refractory material, and a group of one-to-one rows 12 lined up in the width direction of the sintered raw material 2 are arranged inside the frame, and the sintering furnace 10 passes through the lower part of the ignition furnace 10. The condensing material 2 is ignited. The ignition furnace 10 is located above the wind mix 14 at the forefront, and ignition of the two layers of sintered raw materials occurs only on the surface, but as the pallet 8 moves on the wind mix 14, the combustion zone moves downward. The combustion gas finally reaches the grate (not shown), where it is sucked in and discharged through the main duct (main duct) 16.The above is the ignition work of the DL type sintering machine currently being carried out, but in the conventional method, there are two There are cost issues. The first point is a reduction in ignition energy. Using coke oven gas currently generated from coke ovens as a heat source,
Although the basic unit is 1.5 to 2.0 Nm''/ts, efforts are being made to further reduce it.The second point is to improve the sintering yield.

In the sintering process, the upper layer is rapidly heated and cooled, so its quality and yield tend to be extremely poor compared to the middle and lower layers. Various measures have been devised as countermeasures against this problem.

Tables 1 and 2 show countermeasures for each of the above problems that have been proposed to date, as well as their problems. Table 1 shows measures to reduce ignition energy. The technology of carbonaceous material scattering (Japanese Patent Publication No. 194218/1983) will be explained.

This measure aims to eliminate the current ignition furnace and reduce the cost of sintering equipment by sequentially cutting out red-hot carbonaceous material on the surface of the sintered raw material fed with pallet K ore. The sintered layer will not ignite unless the temperature of the carbon material is 900 to 1000℃ or higher, and maintenance of the high-temperature red-hot carbon material cutting equipment is an issue, and the probability of ignition occurring in the sintered layer is low. It takes some getting used to, so it is difficult to put it into practical use.

In addition, Table 2 shows measures to improve the sintering yield, among which two-stage charging (PTL 56-43296
The technology disclosed in Japanese Patent Publication No. 57-169025 will be explained.

This countermeasure is a technology that improves the quality of sintered ore by producing two types of blended raw materials, improving the raw material particle size distribution in the vertical direction of the raw material layer and the density distribution of coke. However, with this technology, the amount of coke exposed in the surface layer of the mortar is small, so the effect of improving ignition performance is small, and the fuel distribution in the surface layer during blending is sufficiently precise to achieve the intended coke combustion. I can't control it well. In addition, equipment costs are high because two charging hopper systems are required. <Required Technology> The present invention overcomes the drawbacks of the prior art described above, reduces ignition energy, and improves surface sintered ore quality. The purpose of this is to improve production efficiency and improve yield.

For this purpose, we focused on the following conditions.

■ Reliable ignition of the sintered layer.

■ Equipment costs are low and maintenance is easy.

■ Significant improvement in ignitability of the surface layer.

■ It should be easy to control so that the combustion of coke powder in the layer can be carried out after surface treatment.

<Structure of the Invention> The present invention was made in order to satisfy the requirements stated in the previous paragraph, and its characteristics are that the raw material feeding hopper feeds the sintered raw material to the pallet, The method of igniting a sintered raw material in which the surface of the sintered raw material is ignited includes a method of igniting a sintered raw material in which the surface layer of the raw material is ignited after unignited fuel is supplied.

This trap has the following effects.

(2) Since the fuel is supplied to the surface of the sintered raw material in the A-let where the raw material is supplied and the layer is formed, fuel with good ignitability exists only in the surface layer, and the ignitability is greatly improved. Further, since no mixing occurs within the bed, control for achieving the intended combustion of fine coke within the bed is easy. Furthermore, unlike the two-stage charging equipment, there is no need to perform two systems of raw material processing, so the equipment cost is low.

■ Since the sintered surface layer is ignited after unignited fuel is supplied, the fuel in the raw material can also be ignited during the ignition operation, so ignition of the sintered layer is reliable. In addition, since unignited fuel is dispersed, the supply is in the low temperature range (100 to 500
0), and there is no need to handle high-temperature substances, making maintenance easy.

<Specific explanation of structure 0 of the invention> The present invention will be described below based on examples. As shown in Fig. 2, the sintering raw material 2 is charged from the sintering raw material feed hopper 4 through the raw material charging chute 6 to the sintering nozzle 8, as in the conventional method, and is charged to a predetermined depth. The surface is leveled. Then,
Unignited fuel 18 is supplied to the ignition assisting device 17 on the surface of the raw material in the pallet. Spraying should desirably satisfy the following four conditions: ■ An ignition auxiliary device 2 A device that sprays fuel on the surface layer;
In order to achieve desired combustion in the surface layer, for example, unignited fuel is uniformly spread.

Possible types of equipment include a spreading conveyor or a spreading nozzle system as shown in FIGS. 3 and 4.

FIG. 3 shows that the unignited fuel 18 in the fuel hog A-19 is cut out by the fuel cut-out device 2o and supplied to the conveyor 21, and then transferred to the conveying end of the conveyor by the fuel dispersion device. 22 and onto the surface of the sintered raw material 20 charged into the sintering pallet 8 and whose surface has been smoothed. The system shown in FIG. The fuel is ejected from the fuel ejection part 24 by the dispersing air 23,
This is a system in which the water is supplied via a dispersion plate 25.

■ Composition of the fuel to be sprayed: It is desirable to have low volatile content to prevent smoke generation due to evaporation of volatile content, and low moisture content to improve ignitability. The temperature range of the unignited fuel is desirably 150° C. or below, which is a range that can be easily handled, and is within the heat resistance limit of conveyors and the like. As the fuel actually used, coke breeze or coal with a low volatile content can be considered.

■ Particle size of dispersed fuel: In the case of solid fuel, as shown in Figure 5, the smaller the particle size, the faster the combustion speed. Since the ignition characteristics are better when the particle size is smaller, the particle size is reduced within the range that handling allows.

■ Spreading 1: As energy amount lX10"If'a-
#'♂~100XIO1'Eat/d, preferably 1'i 4.000 Kal/rr! degree is Z
,,.

The raw material 2 after being repeatedly sprayed with fuel enters an ignition furnace 10 which is usually adjacent to the raw material 2, and ignites the surface of the raw material by burning coke oven gas and the like.

In the method of the present invention, since fuel is present in the surface layer, the temperature condition is set at 120°C (from about 1°C to 10°C) compared to the conventional ignition method.
The time required for one ignition can be reduced from about 6 (lsec) to about 30 SDc.As a result, the energy required for ignition can be reduced, and the current 00G source of 2 Nrn'/t-s can be reduced. The unit was reduced to I Nrn”/t s. Also.

After leaving the ignition furnace, the heat retention effect of the high-temperature air that passed through the ignited fuel layer makes it possible to obtain a heat pattern like the one-dot chain line in Figure 5, which causes a rapid increase in hot water temperature at the sintered surface layer. Because it can prevent you from falling.

Deterioration of the quality of the sintered surface layer can be prevented.

<Examples of the Invention> Table 4 shows the results of attempts at sintering using the various ignition methods shown in Table 3.

2 As the sintering conditions, the coke powder ratio in the sintering layer was 3%, the moisture content was 6%, and the layer thickness was j and H500%.

Table 4: Sintering test results・:;* When 00G was not used, ignition was difficult. In comparison, it was possible to obtain sintered ore with a high yield with a small amount of ignition energy. <Effects of the Invention> The following effects can be expected with the present invention 7. Surface ignition energy of sintered ore The amount can be reduced and the required OOG etc. can be reduced.

■ Improved yield and quality of the sintered surface layer.

■ No large-scale process improvements are required, such as preheating sintering or two-stage charging.

■ Ignition can be reliably performed on the sintered surface layer.

■ The amount of fuel sprayed on the surface layer can be easily changed, making it easy to control the quality of the upper layer.■ Maintenance is easy because there is no need to handle high-temperature substances such as red-hot materials.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view of a conventional ignition device, FIG. 2 is a schematic sectional view of a device for carrying out the ignition method according to the present invention, FIGS. 3 and 4 are schematic sectional views of a fuel dispersion device, FIG. 5 is a graph showing the difference in the heat pattern of the upper surface layer between the method of the present invention and the conventional method. 2... Sintering raw material, 4... Sintering raw material feeding hopper, 6
...Ore feed chute, 8...Sintering machine noglet, 10
...Ignition furnace, 12...Ignition furnace, 14...
・Wind Zex, 16... Main Dak), 17・
...Ignition assist device, 18...Unignited fuel, 19...
・Fuel hopper, 20...Fuel cut-off device, 21・
...Conveyor, 22...Fuel distribution device, 23...
Dispersion air, 24... Fuel ejecting section, 25... Dispersion plate. Agent Patent attorney Masamitsu Akizawa and 2 others 71'l [ffi 8 62nd left 3m left 41 5m

Claims (1)

[Claims] (1) A method for igniting a sintered raw material in which a sintered raw material is fed into a noe let by a raw material feeding hopper, and the surface of the sintered raw material is ignited. A method for igniting a sintered raw material, characterized by supplying unignited fuel to the surface of the sintered raw material and then igniting the surface layer of the raw material.