JPS6210227A - Sintering operation method - Google Patents

Abstract

PURPOSE:To control quality in height direction of sintered layer on pallet uniform, by dehumidifying sucked air only for ore discharging part to a predetermined humidity or below and supplying bit in a continuous sintering machine. CONSTITUTION:Sintering material 2 is charged from a hopper 1 in lamellar stat to plural pallets connected to a sintering machine 3 in endless mode, fired by an ignition furnace 6, sucked by a main exhauster 5, and crushed stones are sintered and discharged from the ore discharging part 11. Thereat, in the part 11, air sucked from an air intake 10 is dehumidified to a prescribed humidity by a dehumidifier 9, and supplied to the sintering material layer 2 from a hood 7 through a duct 8. Variation of region absorbing dehumidified air as the variation of sintering end points is controlled by operating a damper 13 in a hood 7. In this way, the variance of post calcining strength in height direction owing to the unevenness of heat supply in material layer height direction is solved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a sintering method that stabilizes the quality of sintered ore by dehumidifying the suction air in the ore discharge section during the production of sintered ore in an endless continuous sintering machine. Concerning the method of drying.

[Conventional technology]

Sintered ore fired on pallets in a sintering operation typically has 41 of its strength in the height direction. Generally, the shutter strength is low at the top of the layer, resulting in a relative lack of heat, and as you move toward the bottom, more heat is supplied, and the shutter strength increases accordingly. There is.

This is considered to be a characteristic of the raw material firing method using the continuous coupling machine, which is the object of the present invention.

In order to reduce the amount of coke used as a heat source, it is necessary to eliminate the above-mentioned variation in the strength of sintered ore. Coke consumption per unit (kg/1-si)
nter) c7) reduction can be achieved.

To solve this problem, some sintering machines use segregation charging, in which the amount of coke charged in the upper and lower layers is varied, or the grain size is varied in the height direction. However, in this type of segregation charging, the raw material supply equipment is large and has a complicated structure, and it is difficult to modify the existing sintering machine, and even with such equipment, it is difficult to achieve the desired segregation. It is difficult to provide this in a layer. In addition, for this segregation charging, the procedures for controlling the cutting out of the raw materials to be mixed and adjusting the particle size become complicated, which increases operational costs.

Therefore, JP-A-58-104127 and JP-A-58-16
No. 4734 proposes an operating method for maintaining constant quality by dehumidifying the moisture in the suction air from the latter stage of the ignition furnace to the ore discharge section. However, as shown in Figure 3, in this case, there is a lack of heat immediately after the ignition furnace, and dehumidifying here also causes uneven heat supply in the longitudinal and height directions of the sintered layer. Accordingly, the quality after sintering also varies in the height direction within the layer, which is a factor causing a decrease in yield.In the lower layer of the Yumata pallet raw material layer, the combustion zone area 14 is located on the ore discharge side 16, According to the temperature measurement results in the upper layer,
Compared to the middle layer, the high temperature retention time is longer and there is a tendency for excessive heat supply. This is represented by a heat pattern as shown in FIG. 3(b). This difference in heat supply between the upper, middle and lower layers of the raw material layer causes non-uniformity in properties such as strength of the sintered product in the height direction of the raw material layer.

[Problem that the invention seeks to solve]

The object of the present invention is to solve the problem of unevenness in strength after firing in the height direction due to non-uniform heat supply in the height direction of the raw material layer, which is peculiar to the continuous sintering machine.

[Means for solving problems]

In the present invention, sintering raw materials are loaded in layers into a plurality of pallets connected in an endless manner, and after the raw materials are ignited, the fine ore is sintered while sucking air passing through the sintering raw material layers from the bottom of the pallets. In the operating method of the continuous sintering machine, the suction air only in the ore discharge section is dehumidified to below a predetermined moisture value and supplied to make the quality uniform in the height direction within the sintered layer on the pallet. This is a sintering operation method characterized by control.

[Effect]

In the sintering operation, the relationship shown in FIG. 2 was obtained between the moisture content in the suctioned air and the gas utilization rate ηco in the exhaust gas that passed through the raw material layer after suction. The gas utilization rate ηco is calculated by excluding CO2, which is produced due to the decomposition of carbonates in the sintering raw material.<Co2
It is expressed by the concentration C02* and the C0 concentration, and is expressed as ηco-(GO2 end)/(CO+GO2). The relationship between atmospheric moisture and ηCo is as follows (1)
, (2) and (3).

GO+H20(g)=CO2+H2-(1)H2+y2
o2 = I (20... (2) CO ten gift o2 = co
2... (3) That is, as the moisture content increases, oxidation of Co gas is promoted through H20 gas. Among these, equation (3) is an exothermic reaction,
This reaction will contribute to an increase in temperature within the sintered layer.

Therefore, in order to suppress this calorific value, the present invention focuses on the function of moisture in the sucked air, and in order to cope with the tendency of excessive heat supply in the lower part of the sintered layer as described above, In order to remove the heat supply due to the exothermic reaction of formula (3), the suction air is dehumidified to suppress the occurrence of the exothermic reaction according to formula (3) described above, thereby preventing excessive heat supply in the lower layer of the sintered layer. This is an attempt to prevent this phenomenon.

On the other hand, as mentioned above, there is a lack of heat in the ore feed section where the sintering reaction progresses in the upper part of the raw material layer, so the moisture in the air is actively used to take advantage of the reaction in equation (3) to heat up. Try to increase the supply.

However, the combustion zone area in the raw material bed is constantly changing depending on the operating conditions, and the area on the pallet where dehumidified air is required for the sintering reaction in the lower layer of the raw material bed is always changing. Therefore, in actual operation, the sintering completion point in the layer is constantly monitored using the temperature measurement results directly under the pallet, etc., and the suction area of dehumidified air is divided according to the fluctuations, for example, with the hood 7, and a damper 13 is installed in each. By setting 0 or more, the exothermic reaction is controlled by removing the moisture in the suction air without performing segregation charging, which distributes the coke content and particle size in the height direction. The heat supply state in the height direction can be made uniform, and the strength after sintering can be made uniform.

〔Example〕

An example of application to actual sintering operations is shown below.

Production volume 7000t/B, suction volume 8L 900ONr
As shown in Fig. 1, the hood 7 is attached to the DL sintering machine 3 for n'7 minutes.
, a duct 8, a dehumidifying device 9, and an atmospheric suction port 10 were installed to carry out the sintering operation. As the dehumidifying device 10, a refrigerating type dehumidifier was used. Changes in the absorption area of dehumidified air due to changes in the sintering completion point were adjusted by operating a damper 13 in the hood.

The operation was carried out by controlling the moisture content of the suction air supplied to the sintering machine discharge section to 10 g/Nm' or less, which provides the best controllability.

Table 1 shows a comparison of operational data for a period in which the present invention was applied and a period in which a conventional operation method was used in which the operation method from the latter stage of the ignition furnace to the ore discharge section was dehumidified.

As is clear from Table 1, the coke consumption rate is reduced by applying the present invention, but the falling strength can be kept at approximately the same value. In particular, the fall strength results for local sampling samples at three points in the height direction, which were conducted to investigate the variation in fall strength in the height direction within the layer, showed that the value in the lower layer of the layer was lower compared to the conventional method. This made it possible to significantly reduce the variation in height.

Furthermore, in terms of productivity, the adoption of the present invention has made it possible to significantly improve the yield.

〔Effect of the invention〕

By adopting the present invention, as shown in Table 1, the variation in drop strength in the height direction within the layer has been greatly reduced, and the coke consumption rate has also been reduced, improving the yield of sintered products. This also has a significant effect on cost reduction.

Table 1

[Brief explanation of drawings]

Fig. 1 is a system diagram of an embodiment of the present invention, and Fig. 2 shows the humidity in the suction air and the gas utilization rate ηco:CO of the exhaust gas that has passed through the layer.
2 bottles/ (CO+GO 2 bottles),! =(7) A diagram showing the fsEI relationship, and FIG. 3(a) is a schematic side view of the sintering machine. FIG. 3(b) is a graph showing the heat pattern. 1... Sintering raw material charging hopper 2... Sintering raw material layer 3... Endless continuous sintering machine 5
...Main exhaust fan 6...Ignition furnace 7...Hood 8...Duct 9...Dehumidifier 1
0... Atmospheric suction 11... Ore discharge section

Claims (1)

[Claims] 1 A continuous method in which sintering raw materials are charged in layers into multiple pallets connected in an endless manner, and after the raw materials are ignited, the fine ore is sintered while sucking air passing through the sintering raw material layers from the bottom of the pallets. In the operating method of the sintering machine, the suction air only in the ore discharge section is dehumidified to below a predetermined moisture value and supplied, and the quality is controlled to be uniform in the height direction within the sintered layer on the pallet. A sintering operation method characterized by: