JPH01306528A - Method of controlling combustion of raw material firing part on pallet of sintering machine - Google Patents

Abstract

PURPOSE:To provide the stabler quality of sintered ore, the higher yield thereof, etc., by calculating the total quantity of heat in the part of the temp. higher than the firing temp. from the raw material surface layer temp. distribution after ignition and pallet moving speed, comparing the same with a set value and regulating the fuel supply rate of an ignition device. CONSTITUTION:The raw material surface layer temp. in the pallet progressing direction right after firing by the ignition device 3 is continuously measured by a scanning type radiation thermometer 5 on the pallet 2 of the sintering machine and is transmitted to an arithmetic processor 7 by which the raw material surface layer temp. distribution 13 is obtd. The arithmetic processor 7 determines the holding time (t) of about >=900 deg.C which is the firing temp. of carbonaceous material from the pallet moving speed obtd. by a detector 6 and the raw material surface layer temp. distribution 13 and determines the area Qr of about >=900 deg.C. The measured value Qr is sent to a comparator 8 which compares the value with the set value Qs in accordance with the moisture in the raw material, the layer thickness, the pallet speed, the fluctuation of the carbonaceous material on the raw material surface, and the fluctuation in the calory of gaseous fuel. The opening degree of a control valve 10 is regulated via an instruction device 9 for regulation of the gaseous fuel of the ignition device in this way, by which the fuel supply rate of the ignition device 3 is regulated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a combustion control method for a raw material ignition section on a pallet of a sintering machine.

EConventional technology J In general, a continuous sintering machine has a feeding hopper l as shown in
The raw material mixed with carbonaceous materials is charged into a pallet 2, and the igniter 3 ignites the carbonaceous material contained in the surface layer of the raw material, and the blower 4 sucks and ventilates the raw material downward. Combustion progresses downward from the surface layer, and sintering is completed in the ore discharge section of the sintering machine.

In the manufacturing process of such sintered ore, the quality of the ignition of the raw materials in the surface layer by the ignition device affects the quality and yield of the sintered ore, and also reduces the manufacturing cost of sintered ore. In order to do so, it is necessary to prevent excessive fuel consumption of the ignition system as much as possible. In view of the above, in sintering operations, the above-mentioned problems are usually solved by constantly monitoring the ignition situation and manipulating the ignition conditions of the ignition device.

A method for this purpose is to obtain the heat retention index and cooling index in the thickness direction of the raw material layer, and adjust the suction ventilation distribution and the distribution in the layer thickness direction so that these distributions are constant, as in JP-A-58-144432. Or, like JP-A No. 63-33527,
It has been proposed to measure the surface temperature within the ignition furnace along the pallet traveling direction and to control the amount of fuel gas supplied to the ignition device according to the heat retention index.

As shown in FIGS. 4 and 5, the ignition condition on the surface of the raw material layer is constantly changing due to disturbances such as the thickness of the raw material layer, the pallet moving speed, and the moisture content in the raw material. Figure 4 shows the ignition heat consumption rate versus the ratio of the raw material layer thickness and pallet speed, and Figure 5 shows the relationship between the moisture content in the raw material and the surface temperature of the raw material layer. be. These disturbances include, for example, the pallet moving speed, which increases the amount of ignition fuel by increasing the speed and decreases the amount of fuel by decreasing the speed, so that the amount of ignition heat is always the same. There are some factors that do not affect the required amount of ignition heat per unit weight, while others, such as the moisture content and carbon material content on the surface of the raw material layer, change the required amount of ignition heat. In spite of this, conventional controls have not been implemented accordingly.

Therefore, even if the ignition heat amount is maintained at the reference value, ignition failure or excessive ignition may occur due to the above-mentioned disturbance.

As described above, although conventional methods can control disturbances that do not affect the required amount of ignition heat, they are insufficient for disturbances that do affect the required amount of ignition heat, and this makes it difficult to control the material ignition section on the pallet. It was a hindrance.

[Problems to be Solved by the Invention] The present invention overcomes the drawbacks of the prior art in which desirable combustion control of the ignition part on the surface of the raw material layer of a continuous sintering machine cannot be performed, and improves the quality of sintered ore by stabilizing the ignition state. The aim is to improve stability and yield, and reduce the ignition heat consumption unit.

[Means for solving the problem 1] In order to completely eliminate the influence of disturbance factors on ignition as described above, the surface layer temperature of the raw material after ignition is measured, and based on this, the amount of fuel supplied to the ignition device is adjusted. It is essential to adjust the Based on this basic knowledge, we developed a control system consisting of the following technical means.

(1) Continuously measure the temperature of the surface layer of the raw material after ignition.

(2) Measurement is performed using a radiation thermometer that can scan in the direction of pallet movement, and the measurement range is 250 mm in front and back of the point where the flame of the ignition device collides with the raw material.

(3) Measure the surface temperature distribution of the raw material, input the measurement result to the comparison calculation device, compare it with the set value, and adjust the difference via the fuel supply amount control device of the ignition device.

FIG. 1 shows the configuration of an apparatus used for combustion control in the method of the present invention. This device is equipped with a scanning radiation thermometer 5 that can measure the raw material surface temperature distribution 13 in the pallet traveling direction of the raw material ignition section in the hood of the ignition device 3, and in addition, a pallet movement speed detector 6 and these Information arithmetic processing device 7
, a comparison device 8 for comparing set values and actual values, an ignition device fuel supply amount adjustment instructing device 9, and a control valve 10 for actually adjusting the fuel supply amount for the ignition device.

The scanning radiation thermometer 5 is located along the traveling direction of the pallet 2.
It is installed in the ignition hood 3 at an angle of about 50 degrees, and the scanning angle is 25 degrees.

In addition, the measurement range of the raw material surface temperature is the flame 11 of the ignition device.
The area is 250 mm in front and rear of the collision point between the original IEI l 2 and the original IEI l 2. Therefore, the radiation thermometer 5 scans the above range, and the raw material surface temperature distribution 13 after ignition.
is obtained.

The measurement signal obtained from the radiation thermometer 5 is transmitted to the arithmetic processing unit 7 every 30 seconds, and the raw material surface layer temperature distribution 13 is obtained.

Furthermore, the raw material surface temperature distribution 13 obtained by the arithmetic processing device 7
From the pallet movement speed obtained from the pallet movement speed detector 6, the retention time t at 900°C or higher, which is the ignition temperature of the carbonaceous material, is determined, and based on these, 9 is calculated as shown in Fig. 2.
Find the area (Qv) above 00°C.

QT is usually expressed in E°C.5ecl.

The measured value QT obtained by the arithmetic processing device is sent to the comparison device 8, and is preset based on the moisture in the raw material, the layer thickness, the pallet speed, the fluctuation of the carbon material in the surface layer of the raw material, and the calorie fluctuation of the fuel gas. It is compared with a certain set value Qs.

When the measured value QT is lower than the set value Qs, and when it is higher than the set value Qs by 5% or more, the opening degree of the control valve IO is adjusted via the ignition device fuel gas adjustment instruction device 9. Then, the amount of fuel supplied to the ignition device 3 is increased or decreased. This series of operations is a system that automatically adjusts.

[Effect 1] According to the present invention, stable ignition is always possible even when there are disturbances that were an obstacle in the conventional method, and it is possible to improve the yield and reduce the ignition heat consumption unit.

[Example] The present invention will be described in detail with reference to the flow sheet shown in FIG.

First, the raw material 12 is cut out from the ore feed hopper 1 by the cutting device 14 and charged onto the pallet 2.

Although the moisture content of this raw material 12 is adjusted to be extremely constant, there is still considerable variation.

Further, the moisture content of the raw material may be changed by adjusting the ventilation of the raw material 12. Further, the thickness of the raw material 12 charged onto the pallet 2 and the moving speed of the pallet 2 are sequentially adjusted in relation to the ventilation adjustment in the sintered layer.

The raw material 12 charged onto the pallet 2 under such conditions
moves and is ignited by the ignition device 3.

The surface temperature of the raw material 12 after ignition is measured by scanning the scanning radiation thermometer 5 installed on the ignition device 3 along the traveling direction of the pallet 2.

The measurement range of raw material surface temperature is flame 11 of the igniter and raw material 1.
The area is 250mm in front and rear of the collision point of No.2.

The measurement signal obtained from the radiation thermometer 5 is transmitted to the arithmetic processing unit 7 every 30 seconds, and the raw material surface layer temperature distribution 13 is obtained.

Furthermore, the raw material surface temperature distribution 13 obtained by the arithmetic processing device 7
From the pallet movement speed obtained by the pallet movement speed detector 6, the retention time t of 900°C or higher, which is the ignition temperature of the carbon material, is determined.
Based on these, the total heat amount or area (QT) of the portion above 900°C is determined (Figure 2).

The measured value Qs obtained by the arithmetic processing device is sent to the comparator 8 and compared with a preset value Qs. The set value Qs was experimentally determined based on the material layer thickness, pallet speed, water bone in the material,
The amount of carbon material on the surface layer of the raw material and the calorie of the fuel gas are varied to set values that provide stable ignition.

That is, as shown in FIG. 4, the set value Qs is set as a control reference value, and if it is lower than this value, it indicates that ignition has not occurred, which has a negative effect on yield improvement and ignition heat consumption unit.

Further, if it exceeds the set value Qs, it indicates a stable ignition range, and within the range of Q B + 5%, no adjustment is required.

In other words, when the measured value QT is lower than the set value Qs, and when it exceeds the set value Qs by 5% or more,
The opening degree of the control valve 10 is adjusted via the fuel adjustment instruction device 9 of the ignition device, and the amount of fuel supplied to the ignition device 3 is increased or decreased.

Therefore, even if there are disturbances such as the thickness of the raw material layer, moisture content, pallet speed, variation in the amount of carbon material in the upper layer, or variation in fuel gas calorie as described above, the total amount of heat QT above the ignition temperature will be the set value Qs. Since the amount of fuel supplied to the constant ignition device 3 is adjusted, stable ignition can be obtained, which is highly effective in improving the yield and reducing the ignition heat consumption unit.

FIG. 6 shows the difference between (a) the conventional method and (b) the method of the present invention. By adopting the method of the present invention, the variation in QT was drastically reduced compared to the conventional method.

As a result, the phenomenon of insufficient ignition heat or excess ignition heat is reduced, and a constant ignition state can be maintained at all times. As a result, as shown in Table 1, the yield improves by 0.5% and the ignition heat per unit of production reaches 400k. It has become possible to reduce cal/ts.

[Effect of the invention 1] By applying the control method of the present invention, it is possible to quickly respond to changes in layer thickness and pallet movement speed that change from moment to moment due to changes in raw material moisture and changes in sintering air permeability. Became.

[Brief explanation of the drawing]

Figure 1 is a block diagram showing the configuration of the present invention, Figure 2 is an explanatory diagram of the total amount of heat QT above the ignition temperature, Figure 3 is a schematic diagram showing the outline of the sintering machine, and Figure 4 is the effect on the ignition situation. FIG. 5 is a graph showing the influence of layer thickness and pallet speed, FIG. 5 is a graph showing the influence of raw material moisture on the ignition situation, and FIG. 6 is a graph showing the effect of the method of the present invention. l...Feeding hopper 2...Pallet 3...Ignition device 4...Blower 5...Radiation thermometer 6...Pallet movement speed detector 7...Arithmetic processing unit 8... Comparison device 9...Fuel supply amount adjustment instruction device lO...-Adjusting valve 11...Flame 12...Raw material 13...Raw material surface layer temperature distribution 14...Cutting device

Claims (1)

[Claims] 1 In an ignition section combustion control method that detects the temperature of the ignition surface of a continuous sintering machine and controls the fuel supplied to the ignition device, the temperature of the surface layer of the raw material in the direction of pallet movement immediately after being ignited by the ignition device is continuously measured. The total amount of heat in the area above the ignition temperature of the carbon material is calculated from the obtained temperature distribution, and calculated in advance based on the moisture in the raw material, layer thickness, pallet speed, fluctuations in the carbon material in the surface layer of the raw material, and fuel gas calorie fluctuations. A combustion control method for an ignition unit on a pallet of a sintering machine, characterized by comparing it with a set value and adjusting the amount of fuel supplied to an ignition device based on the comparison result.