JPH03211241A - Operating method for sintering machine - Google Patents

Abstract

PURPOSE:To improve the productivity of a sintering machine and the yield of products by setting a target temp. between the temp. rise start point and sintering end point where the fluctuation in an exhaust gas temp. is little and controlling a pallet speed in such a manner that the position corresponding to this temp. is a set position. CONSTITUTION:Exhaust gases are measured at the plural points in the longitudinal direction (progressing direction) of the sintering machine. The fluctuation in the exhaust gas temp. is small between the temp. rise start point A and the sintering end point B if the exhaust gas temp. curve in the longitudinal direction of the machine is determined from these measured temps. The target temp. (preferably in a 150 to 300 deg.C range between C and D) is, therefore, provided between the temp. rise start point A and the sintering end point B and the wind box position to attain this target temp. is determined by a computer. The pallet speed is so controlled that this position attains the position determined by taking the productivity and the yield of the products into consideration.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method of operating a sintering machine.

[Prior art] When producing sintered ore using a DL sintering machine, various operating techniques have been developed to improve the quality of the sintered ore and the product yield.
It has been implemented. Conventionally, the exhaust gas temperature in the longitudinal direction of the sintering machine is measured, a quadratic curve equation that approximates the temperature distribution on the ore discharge side is found, and the position where the temperature reaches the maximum value (sintering end point) is determined at a predetermined position. Generally, the pallet speed is controlled so that the thickness of the sinter layer at the end of the ore discharge section of the sintering machine reaches a predetermined thickness. It has been carried out in As a published patent document, the sintering end point is detected in each width direction from the exhaust gas temperature transition of the wind box in the longitudinal direction of the sintering machine, the average sintering point in the width direction is calculated, and this is set as the target value. There is a method of adjusting pallet speed (Japanese Patent Laid-Open No. 13032/1983).

[Problems to be Solved by the Invention] However, the conventional method of controlling the pallet speed at the sintering end point has the following problems. The shrinkage of the sintered layer increases as it approaches the ore discharge area, and as a result, air leakage due to cracks in the sintered layer and air leakage between the sidewall and the sintered layer increase. These air leaks and the air leakage from the end of the ore discharge section are not uniform over time, and the amount of air leakage changes greatly. Therefore, the fluctuation of the exhaust gas temperature on the ore discharge section side is large, that is, the firing state of the sintered layer Even if there is no change in , the apparent exhaust gas temperature changes, and therefore the sintering end point calculated based on such exhaust gas temperature changes, causing a change in pallet speed, resulting in a decrease in production rate. Also, there is a problem of deterioration of yield.

On the other hand, the method of keeping the layer thickness of the embers constant in the cross-section of the sintered layer at the end of the ore discharge section is difficult because the sensitivity of the monitor camera that detects the thickness of the ember layer changes over time, and the ore discharge section is dust-producing. There is a problem that accurate pallet speed control is not possible due to the extremely low measurement accuracy.

[Means for Solving the Problems] The present invention attempts to solve the above-mentioned problems. One is to measure the exhaust gas temperature at multiple locations in the longitudinal direction of a sintering machine, and to calculate the temperature in the longitudinal direction from the measured temperature. Find the exhaust gas temperature curve formula, find the position on the temperature curve between the temperature rise start point and the sintering end point where the specified temperature is reached, and adjust the pallet speed of the sintering machine so that this position becomes the set position. Another method is to obtain exhaust gas temperature curve equations for multiple rows in the longitudinal direction of the sintering machine, and for each row of exhaust gas temperature curve equations, calculate the temperature curve. Find the position between the temperature rise start point and the sintering end point where the predetermined temperature is reached, and set the set position to be the average position of those positions or the position farthest from the ignition box among those positions. A method of operating a sintering machine characterized by controlling the pallet speed of the sintering machine. In the method, the predetermined temperature is preferably in the range of 150 to 300°C.

[Effectiveness] As shown in Figure 3, the exhaust gas temperature in the machine length direction (progressing direction) of the sintering machine fluctuates greatly on the ore discharge side, especially before and after the sintering end point, but the exhaust gas temperature rises. There is little variation between the starting point A and the sintering end point. Therefore, by setting the predetermined temperature between the exhaust gas temperature rise start point A and the sintering end point, the pallet speed can be appropriately controlled and the production rate and yield can be improved.

[Example] Examples of the present invention will be described in detail below. FIG. 1 is a graph showing an example of exhaust gas temperature distribution of a sintering machine. This example is of a sintering machine with 23 wind boxes. The exhaust gas temperature of the sintering machine changes as the combustion zone is formed in the layer after it is ignited on the top surface of the charged raw material layer, and as the combustion zone descends,
However, up to 70% of the effective aircraft length, the exhaust gas temperature hardly rises and remains at 80 to 90°C. After this, the exhaust gas temperature rises, and a maximum temperature point (sintering end point, abbreviation BTP; the exhaust gas temperature at this point is usually 350 to 450°C) appears at about 95% of the effective length, and then decreases. do. In the example in Figure 1, up to wind box N017, the temperature is 80℃, N0
The temperature rises to 100°C at 18°C, and then rises in a curve (quadratic order) to a maximum of 400°C.

The operating method of the present invention has a pallet speed control index value of 1
Avoid the sintering end point where the exhaust gas temperature fluctuation is large, and move from the temperature rise start point (A) where the exhaust gas temperature fluctuation is small to the sintering end point (
A target temperature is set between B), the wind box position at which the target temperature is achieved is determined, and the pallet speed is controlled so that the position is determined by taking into account the production rate and product yield. . Specifically, pallet speed control is performed using a computer as follows. Input the wind box temperatures at three locations after the exhaust gas temperature rise start point into the computer, determine the coefficients A, B, and C of equation (1), determine the exhaust gas temperature curve formula, and calculate the exhaust gas temperature curve formula. The wind box position at which the target temperature is achieved is calculated from , and the pallet speed is controlled so that this is the set position.

TI=A+ P+ +-131pl +C+ ・
(1) Here, T1, exhaust gas temperature P+ at wind box position P+...Wind box position At, B+, C section...respectively, coefficients of quadratic term, linear term, constant subscript i, width direction of wind box Number of rows when multiple exhaust gas thermometers are installed (see Figure 4) Considering that fluctuations in the exhaust gas temperature are as small as possible and changes in the sintering speed can be ascertained quickly, the target temperature is the exhaust gas temperature of 150 ~300℃ (C in Figure 1)
It is more desirable to set it in the range of ~D).

Temperature sensors that measure the exhaust gas temperature can be installed in one row in the longitudinal direction of the aircraft at the center of each wind box, or as shown in Fig. There may be a row.

Figure 2 shows three rows of temperature sensors in the direction of the pilot (see Figure 4).
The graph shows how the wind box position corresponding to the target temperature of 250° C. is determined by setting the temperature curve for each row. Actually, Pl is determined using a computer by setting TI = 250°C in equation (1). In this case, the wind box value I corresponding to the target temperature of 250°C is P, , P when emphasis is placed on the production rate.
2. When the yield is important, P is the average value of P.
,,P 2. Let it be the maximum value of P3.

Note that when automatically controlled operation is performed, the primary conditions are entered as in the conventional case.

(1) At the upper limit of the suction negative pressure of the main duct, reduce the Pare 7 tospid.

(2+ At the lower limit of the exhaust gas temperature before the main duct electrostatic precipitator,
Reduce pallet speed.

Table 1 compares the production rates of the method of the present invention (conditions: target temperature 250°C, set wind box position 20.2) and the conventional method. The conventional method (2), which is a method of controlling the pallet speed at the end point, is a method of keeping the layer thickness of the embers constant on the cross section of the sintered layer at the end of the ore discharge section.
An improvement of 0.05 T/m''h was obtained using the method of the present invention.

Table 1 [Effects of the Invention] In the present invention, a target temperature is set between a temperature rise start point and a sintering end point where there is little fluctuation in exhaust gas temperature, and the pallet is moved so that the position corresponding to this temperature becomes the set position. Since the speed is controlled, the production rate and product yield are improved compared to conventional methods.

[Brief explanation of drawings]

Figure 1 is a graph showing an example of the exhaust gas temperature curve in the machine length direction of a sintering machine, Figure 2 is a graph diagram showing the exhaust gas temperature curve when three rows of temperature sensors are installed in the machine length direction, and Figure 3 is the exhaust gas temperature curve. FIG. 4 is a graph showing the fluctuation of exhaust gas temperature at the curve and wind box position, and is a diagram showing the arrangement of temperature sensors when a plurality of rows of temperature sensors are provided in the longitudinal direction.

Claims (6)

[Claims] (1) Measure the exhaust gas temperature at multiple locations in the longitudinal direction of the sintering machine, calculate the exhaust gas temperature curve formula in the longitudinal direction from the measured temperatures,
The method is characterized in that a position at which a predetermined temperature is reached between a temperature rise start point and a sintering end point on the temperature curve is determined, and the pallet speed of the sintering machine is controlled so that the position reaches a set position. How to operate a sintering machine. (2) In claim 1, the predetermined temperature is 150 to 300°C.
How to operate a sintering machine to set the temperature between. (3) Find exhaust gas temperature curve equations for multiple rows in the machine length direction of the sintering machine, and for each row of exhaust gas temperature curve equations, determine the temperature at a predetermined temperature between the temperature rise start point and sintering end point of the temperature curve. 1. A method for operating a sintering machine, which comprises determining the position where the position is, and controlling the pallet speed of the sintering machine so that the average position of those positions becomes the set position. (4) In claim 3, the predetermined temperature is 150 to 300°C.
How to operate a sintering machine to set the temperature between. (5) Find exhaust gas temperature curve equations for multiple rows in the machine length direction of the sintering machine, and for each row of exhaust gas temperature curve equations, determine the temperature between the temperature rise start point and the sintering end point of the temperature curve. 1. A method for operating a sintering machine, which comprises determining the position where the ignition box is located, and controlling the pallet speed of the sintering machine so that the position farthest from the ignition box among those positions becomes the set position. (6) In claim 5, the predetermined temperature is 150 to 300°C.
How to operate a sintering machine to set the temperature between.