JPS58171533A - Operating method for sintering device - Google Patents

Abstract

PURPOSE:To obtain sintered ore having less variation in quality, by regulating the flow of wind according to the value calculated in accordance with the heat insulating index at the respective points in a sintering raw material layer and controlling the heat insulating index within a specified layer. CONSTITUTION:Sintering raw material layer 8 is formed in upper pallets 7 moving toward an ore discharge part by the bedding supplied from a bedding layer hopper 5 and the raw material sintering ore supplied from a raw material hopper 6. The layers 8 are ignited in a sintering part and upon completion of the sintering, the sintered material is discharged from an ore discharge part. During this time, air is sucked 10 and supplied through the wind boxes 9 disposed below the pallet 7 and the temp. is detected with temp. sensor 11 in a number of places inserted and disposed in the layer 8, then the signal thereof is oscillated. The signal is received 12, and the heat insulating index from the heat pattern of the layer 8 and the deviation between the heat insulating index and a set range of the heat insulating index is calculated by a calculator 13 for heat insulating index. The opening of the respective dampers 15 disposed in the box 9 is changed by a control device 14 for damper opening according to the calculated deviations to control the suction negative pressures in the lower part of the layer 8, whereby the heat insulating index is protected approximately constant.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of operating a sintering apparatus in which the air volume is adjusted based on a value calculated based on the heat retention index at each point within a layer, and the heat retention index is controlled to a specific value.

Currently, sintering of ore is widely used industrially as a method of agglomerating powdered iron using sintering equipment such as the Dwight Lloyd type or the Greenawalt type.

However, when sintering is performed using these conventional sintering devices, the quality of the sintered ore is extremely poor in the upper layer (0 to 150 mm) of the sintered layer, and the yield between the upper and lower layers is greatly uneven. be. The reason for this unevenness in quality is that the amount of air passing through the ore layer is adjusted using a constant suction negative pressure system, and when the upper layer is burned, the amount of heat is insufficient due to the cooling caused by the intake air. This is thought to be due to the fact that sintering is not performed.

FIG. 2 shows the amount of exhaust gas and the temperature in the sintering raw material bed when sintering was carried out using the ladle testing apparatus shown in FIG. The equipment used for the pot test is as shown in Figure 1, with the raw material layer (1)
410 mm and bedding layer (2) It has 40 mm and T from the top surface of the layer.
□100, T220o, T3300, T4385
4 from each point in the layer of Ryu and Ta205 and the top surface of the layer
Temperature measurement points are provided at points within the first bedding layer of 307 f1m.

It is clear from Figure 2 that the maximum temperature at each measurement point is almost the same, but the higher the f layer, the longer the high temperature retention time.
On the other hand, the air flow rate continues to gradually decrease until the latter half of sintering, and increases rapidly at the end of sintering.

As a result of intensive studies based on the above knowledge, the present inventors have found that by adjusting the air flow rate supplied to the sintered raw material layer, the heat retention index can be controlled within a certain range and sintered ore with less uneven quality can be obtained. At the same time, they found a way to improve the production rate and completed the present invention.In other words, the present invention is based on a control system that performs sintering while blowing air to the sintering raw material.
0, Time when the point exceeded 1000℃ and 1000℃
When the time when the temperature drops to 100% is taken as koji, t2 (m1n), and heat retention index Q ("C・m1n), respectively, by adjusting the air volume supplied to the sintering raw material, the value of the heat retention index Q can be set to 300. The present invention provides a method for operating a sintering apparatus that controls the temperature at ~700°C/min.

If the points that intersect with are times t1 and t2 (min), then [
However, T is defined as the temperature at each point in the heat pattern], and Q is the time integral value of the temperature at a temperature of 1000° C. or higher, and is the area of the shaded portion (4) in FIG. 3.

If Q is less than 300°O-min, sintering will not be sufficient and the yield (10-sieve-on product) will decrease;
When C-m1n is exceeded, sintering is excessive and no improvement in yield or quality can be seen.

According to the method of the present invention, the high heat retention time, which is a factor of the heat retention index, is controlled by the air flow rate, and the heat retention index is maintained within a certain range, resulting in uniform quality and improved production.

Next, the method of the present invention will be explained in more detail with reference to the drawings. FIG. 4 is a schematic diagram of a Dwight Lloyd sintering machine implementing the method of the present invention. The bedding supplied from the bedding layer conch (5) and the raw material sintered ore supplied from the raw material conduit (6) are moved toward the ore discharge section (right side in the figure), and are transported to the upper pallet. A sintering raw material layer (8) is formed on (7). The sintering raw material layer is ignited in the ore supply section (left side in the figure), and when sintering is completed, it is discharged from the ore discharge section. A wind box (9) is installed below the pallet (7), and two blowers (10) with constant suction negative pressure perform suction to supply air to the raw material sintered ore layer on the pallet (7). do. The pallet (7) is provided with temperature sensors (11) inserted into the sintered ore layer at several locations (for example, 5 locations) on the top and bottom.
A detected temperature signal is transmitted by a transmitter (not shown) attached to 1). The signal from the sensor (1) is received by a fixed receiver (12), and the heat retention index calculation device (13) calculates the heat retention from the hidden pattern of each layer of the sintered raw material layer obtained based on the signal. The index and the deviation between the heat retention index and the set heat retention index range are calculated, and based on the deviation, the damper opening control device (14) controls the opening of each damper (15) disposed in the wind box (9). is changed and the suction negative pressure at the bottom of the raw material layer is adjusted.

Note that the blower may be a two-base blower, but as in this example, if there are two blowers, one for the first half of sintering (for low suction and negative pressure) and one for the second half (for high suction and negative pressure), the operating range will be wider and the maintenance will be further improved. It becomes easier to manage the heat index. Furthermore, it is also possible to use three or more blowers. In the method of the present invention, the air volume is controlled by adjusting the opening degree of the damper installed in each wind box, so the total air volume is always constant.

In addition, the damper opening degree can also be controlled manually. In this case, the relationship between the air volume of each wind box and the heat retention index is obtained in advance, and the optimum heat retention index is calculated based on the heat retention index obtained by the heat retention index calculation device. Adjust the air volume by manually adjusting the damper opening as indicated.

However, according to the method of the present invention, as shown in FIGS. 5 and 6, in the initial stage of sintering (the upper part of the sintered layer is sintered), the air volume is reduced compared to the conventional method, and the sintered zone (heat front)
The rate of descent of sintering decreases, and as the end of sintering approaches, the air volume increases and the heat retention index is kept almost constant.

As described above, according to the method of the present invention, the heat retention index is maintained at an optimal value throughout the sintering process by adjusting the air volume, so the quality of the entire sintered layer becomes uniform, and the increase in air volume in the latter half Overall production increases.

The method of the present invention will be explained in more detail below based on Examples.

Example Using the pot test apparatus (320wfl x 410mm) shown in Figure 1, the suction negative pressure was changed stepwise from -30011Aq to -250011LAq in steps of 500111Aq.
Then, sintering was carried out by adjusting the air volume as shown in Fig. 5.

Raw materials used are Hamasure H15%, Godwaji 29chi,
Ryodose 8 F 29.3%, iron sand, scale, limestone, silica stone, to which 501 liters of return ore was added, and 4 liters of coke please was added to the total. The results obtained are shown in Table 1 and Figures 6 to 8 in comparison with the conventional method.

Table 1 As is clear from Table 1 and Figures 6 to 8, in the method of the present invention, the heat retention index increases in the first half, decreases and becomes flat in the second half, and the production rate improves by about 16 inches, and the rotation The difference in strength and reduction powdering rate between the upper and lower layers was reduced, resulting in less uneven quality and improved yield.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of the pot testing device, Fig. 2 is a graph showing the conventional sintering situation, Fig. 3 is an explanatory diagram of heat retention instructions, and Fig. 4 is a schematic diagram showing a specific example of the method of the present invention. 5 to 8 are graphs showing the results of the method of the present invention in comparison with the conventional method. The main symbols in the figure are as follows. 8: Sintering raw material layer, 9: Wind box, 11: Temperature sensor, 15: Damper mesh Fig. 4 Fig. 5 - Fig. 6

Claims (1)

[Claims] (1) In a control system that performs sintering while blowing air to the stacked sintering raw materials, the temperature at each point above and below the layer is set to T (C), the time when the point exceeds 1000°C, and the temperature is lowered to 1000°C. When the time t□, t, (min) and the heat retention index Q (0・min) are respectively determined, the value of the heat retention index Q is set to 300 by adjusting the air volume supplied to the sintering raw material. ~700”Cm
A method of operating a sintering apparatus characterized by controlling the sintering device to 1n.