JP2005187841A - Method for controlling pallet speed in sintering machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for controlling pallet speed in a sintering machine with which the pallet speed can be controlled with good followability by compensating a time delaying characteristic in a temperature measuring means, in the sintering process. <P>SOLUTION: In the pallet speed control method for controlling speed of the pallet 3 when sintering raw material 20 is supplied on the pallet 3 in the sintering machine and carried to an ore discharging part, exhaust gas temperature is measured with thermocouples 5 set in a plurality of wind boxes 4 in the machine length direction, and the time delaying characteristic of the measured temperature is compensated with a reverse filter 6. The burning point is assumed based on the relation between the wind box position in the machine length direction and the exhaust gas temperature at an BTP assumption part 7 based on the output of the reverse filter 6, and a deviation between the target value set at a target value setting part 8 and the assumed burning point, is inputted to a PID control part 10, and thus a driving motor 11 is controlled. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for controlling pallet speed in a dwy-toroid type sintering machine, and more particularly to a method for controlling pallet speed in which exhaust gas temperature is measured at a plurality of locations in the machine length direction and pallet speed is optimally controlled based on the measurement result. .

  Conventionally, as a sintering machine used for the sintering process, a continuous dwy-toroid system suitable for mass production has been mainstream. In order to improve productivity in a dwy-toroid type sintering machine, it is required to appropriately control the pallet speed when transferring the sintering raw material. Various techniques have been proposed as conventional pallet speed control methods. For example, the exhaust gas temperature at a plurality of locations in the machine length direction of the sintering machine is measured, an estimated curve equation of the exhaust gas temperature in the machine length direction is obtained from the measured temperature, and a position at which the predetermined temperature is reached in this estimated curve equation is calculated. There is a method of controlling the pallet speed of the sintering machine so as to reach the set position (see, for example, Patent Document 1). Also, calculate the average firing point in the width direction of the sintering machine based on the transition of the exhaust gas temperature of the wind box installed in the length direction of the sintering machine, and adjust the pallet speed so that it matches the target value (For example, refer to Patent Document 2).

In order to increase productivity in a dwy-toroid-type sintering machine, the estimated position of the firing point may be controlled so as to approach the end of the machine direction. In general, the shrinkage of the sintered layer increases as the sintered raw material approaches the exhausted portion, and the accompanying cracks cause air leakage. In this case, since the amount of air leakage is not uniform over time, the exhaust gas temperature varies, and the estimated position of the firing point apparently varies. In order to reduce the influence of such fluctuations, according to the method of Patent Document 1, control is performed so as to operate the pallet speed based on a predetermined temperature position before reaching the firing point. Further, according to the method of Patent Document 2, control is performed using the average value of exhaust gas thermometers installed at a plurality of locations in the width direction in order to avoid the influence of the firing degree variation that is not uniform in the width direction.
JP-A-3-211241 JP-A-60-13032

  In the conventional pallet speed control method, a thermocouple is generally used to measure the temperatures of a plurality of wind boxes installed in the machine direction. However, the response of this thermocouple has a time delay with respect to the true temperature, and its characteristic is generally expressed by a first order lag characteristic. For this reason, the thermocouple installed in the wind box can obtain the measured temperature at a timing later than the true exhaust gas temperature, so that the influence thereof affects the pallet speed control. In the conventional pallet speed control method described above, although depending on the scale of the sintering machine, for example, in a sintering machine in which a predetermined number of wind boxes and thermocouples are installed in the machine length direction, depending on the firing time, the wind box 1 A problem arises in that a response delay exceeding the number is generated. Furthermore, the temperature is measured in such a manner that the actual temperature fluctuation is dull due to the temperature averaging effect due to the first-order lag of the thermocouple. In this case, in the conventional pallet speed control method, the firing point is estimated by reflecting the dull form of temperature fluctuation, and thus the pallet speed control system that relies on the determination based on such measurement results also operates slowly. The problem is that the productivity in the sintering process is lowered and the quality of the sintered ore is lowered.

  Therefore, the present invention has been made to solve these problems, and compensates for the time delay characteristic of temperature measuring means such as a thermocouple in the sintering process with a simple configuration, and can accurately detect the position in the machine direction. The purpose is to realize a method of controlling the pallet speed in a sintering machine capable of estimating the relationship of the exhaust gas temperature and controlling the pallet speed accurately and with good followability.

  In order to solve the above-mentioned problem, the invention according to claim 1 is directed to a pallet speed in a sintering machine that controls a pallet speed when supplying a sintering raw material onto a pallet of a sintering machine and transferring it to an exhausting section. A control method that measures exhaust gas temperatures at multiple locations in the longitudinal direction, compensates for the time delay characteristics of the measured temperature with an inverse filter, and estimates the relationship between the longitudinal position and the exhaust gas temperature based on the output of the inverse filter The pallet speed is controlled based on the estimation result.

  According to this invention, when controlling the pallet speed in the sintering process, the exhaust gas temperature measured by the temperature measuring means (for example, thermocouple) at a plurality of locations in the machine length direction (for example, the positions of a plurality of wind boxes) is The time delay characteristic is compensated by the inverse filter. As a result, an estimation calculation is performed using the true exhaust gas temperature, and for example, a desired longitudinal position such as a firing point is estimated, and thereby the pallet speed is controlled. Therefore, it is possible to prevent inappropriate pallet speed control due to the influence of the response delay of the temperature measurement means, to be less susceptible to fluctuations in the operating state, and to control the pallet speed accurately and with good followability. It is possible to improve the productivity in the sintering process and improve the quality of the sintered ore.

  The invention according to claim 2 is the invention according to claim 1, wherein the exhaust gas temperature is measured by a plurality of temperature measuring means having a first-order lag characteristic, and the inverse filter is an inverse transfer function of the first-order lag characteristic. It has the characteristic represented by these.

  According to the present invention, in addition to the operation of the first aspect of the invention, the first-order lag characteristic generally possessed by the temperature measuring means such as a thermocouple can be reliably compensated by the inverse filter having the inverse characteristic, and is high. The desired pallet speed can be controlled with accuracy.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein the peak in the estimated curve formula of the exhaust gas temperature is estimated as a firing point, and the pallet speed is based on the estimated firing point. It is characterized by controlling.

  According to this invention, in addition to the effect of the invention of claim 1, the peak is estimated as the firing point using the estimated curve formula of the exhaust gas temperature, and the pallet speed is thereby controlled, so the firing point is It can be controlled to be sufficiently close to the waste mining part, and the productivity in the sintering process can be further increased.

  According to a fourth aspect of the present invention, in the first or second aspect of the present invention, a position at which the predetermined temperature is set in advance in a range from a temperature rise position to a peak in the estimation curve formula of the exhaust gas temperature. And estimating the pallet speed based on the estimation result.

  According to the present invention, in addition to the operation of the invention described in claim 1, the estimated curve position of the exhaust gas temperature is used to estimate the position at which the predetermined temperature is set in the large change region, thereby the pallet speed. Therefore, the pallet speed can be controlled with a desired position corresponding to the state of the sintering process as a target, and productivity in the sintering process can be further increased.

  According to the present invention, the time delay characteristic of the temperature measuring means in the sintering process is compensated by the inverse filter, so that the true exhaust gas temperature can be estimated according to the position in the longitudinal direction, thereby controlling the pallet speed. Since it comprised, the position of the baking point in a machine length direction can be estimated with a high precision, and a pallet speed can be controlled with an exact and favorable followable | trackability. Thereby, it becomes possible to improve the productivity in the sintering process and improve the quality of the sintered ore.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram illustrating a configuration of a sintering machine according to the present embodiment. In FIG. 1, surge hopper 1, ignition furnace 2, pallet 3, wind box 4, thermocouple 5, inverse filter 6, BTP (burning point) estimation unit 7, target value setting unit 8, subtraction unit 9, PID control unit 10 2 shows a dwelloid-type sintering machine including the drive motor 11.

  At the time of operation of the sintering machine shown in FIG. 1, a sintering raw material 20 appropriately mixed in advance is continuously fed by the surge hopper 1. The upper surface of the sintered raw material 20 is ignited by the ignition furnace 2 in a state where the sintered raw material 20 is loaded in the pallet 3 that moves in the right direction of FIG. Then, the sintering raw material 20 on the pallet 3 is combusted from the upper side to the lower side while being transferred at a predetermined speed toward the mining part.

  On the other hand, a large number of wind boxes 4 are provided below the pallet 3 along the longitudinal direction, and the sintering raw material 20 is sequentially fired by sucking the combustion gas from each wind box 4 under a negative pressure. At this time, the temperature of the exhaust gas generated by the combustion is measured by the thermocouple 5 installed in each wind box 4. Based on the measured temperature of each thermocouple 5, it is possible to determine the progress of firing of the sintered raw material 20. The number of installed windboxes 4 and thermocouples 5 can be determined as appropriate according to the state of the sintering process. However, there are restrictions due to the relationship between the length of the sintering machine in the machine length direction and the size of the windbox 4. receive.

  Here, due to the first-order lag characteristic of the thermocouple 5, a time delay occurs in the measured temperature of the thermocouple 5 with respect to the true exhaust gas temperature. In the conventional configuration, the BTP estimation calculation described later is performed using the measured temperature affected by the first-order lag characteristic of the thermocouple 5. However, in this embodiment, by providing the inverse filter 6, A configuration is adopted in which the true exhaust gas temperature is estimated by compensating the first-order lag characteristic of the pair 5, and the BTP estimation calculation is performed using the result.

  Hereinafter, the configuration of the inverse filter 6 will be described. As described above, the characteristics of the thermocouple 5 can be regarded as a first-order lag filter. Here, the transfer function of the first-order lag filter can be described as the following equation (1).

ただし、Ｘ：入力
Ｙ：出力
ｓ：伝達関数の周波数領域を意味するｓ
Ｔ：時定数
一方、逆フィルタ６の特性は、１次遅れ特性を補償すべく、（１）式に対する逆伝達関数で表され、（２）式のように記述することができる。

X: Input
Y: Output
s: s meaning the frequency domain of the transfer function
T: Time constant On the other hand, the characteristic of the inverse filter 6 is expressed by an inverse transfer function with respect to the expression (1) and can be described as the expression (2) in order to compensate the first-order lag characteristic.

この（２）式の伝達関数は周波数領域で表現されたものであるが、これを時間領域で表現すると、（３）式のようになる。

The transfer function of the equation (2) is expressed in the frequency domain. When this is expressed in the time domain, the equation (3) is obtained.

ここで、（２）式及び（３）式に関し、それぞれ入力と出力を入れ替えて一般的に表現すると、次の（２）’式及び（３）’式を得ることができる。

Here, regarding the expressions (2) and (3), the following expressions (2) ′ and (3) ′ can be obtained when the input and output are interchanged and generally expressed.

上記の(３)’式により求められるｙ（ｔ）は、熱電対５の測定信号を表すｘ（ｔ）と、その時間微分の時定数倍とを加えたものである。そして、逆フィルタ６は、この（３）’式に対応するフィルタ演算を行うものであり、その伝達関数は（２）’式で与えられる。これにより、熱電対５の１次遅れ特性が補償され、時間遅れのない真の排ガス温度を算出することが可能となる。

Y (t) calculated | required by said (3) 'formula adds x (t) showing the measurement signal of the thermocouple 5, and the time constant multiple of the time differentiation. The inverse filter 6 performs a filter operation corresponding to the expression (3) ′, and the transfer function is given by the expression (2) ′. As a result, the first-order lag characteristic of the thermocouple 5 is compensated, and the true exhaust gas temperature without time delay can be calculated.

  FIG. 2 is a block diagram showing the configuration of the inverse filter 6. In FIG. 2, it is assumed that N wind boxes 4 and thermocouples 5 are installed, and outputs from the N thermocouples 5 are respectively input to the inverse filters 6. As shown in FIG. 2, the measurement signal X1 of the first thermocouple 5 is input to the adding unit A1 and the differentiating unit B1, and the output of the differentiating unit B1 is input to the adding unit A1. As a result, the output signal Y1 corresponding to the calculation result of the expression (2) ′ or the expression (3) ′ is obtained from the adder A1.

  Further, the same calculation is performed on the measurement signals X1 to XN of the second to Nth thermocouples 5 by the adding units A1 to AN and the differentiating units B1 to BN. As a result, N output signals Y1 to YN, each of which is compensated for the first-order lag characteristics, are obtained and input to the BTP estimation unit 7 in the subsequent stage.

  Next, referring back to FIG. 1, the BTP estimation unit 7 estimates a firing point (BTP: Burn Through Point) in the longitudinal direction based on the output signal of the inverse filter 6 by calculation. The firing point is a point where combustion of the transferred sintering raw material 20 reaches the lower surface. In general, when combustion of the sintering raw material 20 proceeds with the movement of the pallet 3, the exhaust gas temperature tends to rapidly decrease in the last region of the effective machine length.

  For example, FIG. 3 is a diagram illustrating an example of a temperature distribution of exhaust gas in a sintering machine. This example corresponds to the case where the number N of wind boxes 4 is set to 23, and shows a state in which the exhaust gas temperature changes according to the position of the wind box 4. As shown in FIG. 3, the change in the exhaust gas temperature is small up to the position of the 17th wind box 4, but it can be seen that the exhaust gas temperature suddenly increases from the position of the 18th to 19th wind box 4. And it turns out that the peak of exhaust gas temperature arises in the vicinity of the 22nd wind box 4, and turns to decrease after that. In the case of this example, if the peak position is obtained based on the estimated curve formula that matches the exhaust gas temperature, it can be estimated as the firing point.

  The N output signals from the above-described inverse filter 6 are input to the BTP estimation unit 7, and BTP estimation calculation is executed using these output signals. Here, when the position of the i-th wind box 4 is represented by Pi and the temperature obtained by the inverse filter 6 for the i-th thermocouple 5 is represented by Ti, the estimated curve of the exhaust gas temperature in the vicinity of the firing point. The equation is given by the following equation (4).

ただし、Ａｉ：２次項の係数
Ｂｉ：１次項の係数
Ｃｉ：定数
このように排ガス温度の推定曲線式は２次関数で表され、図３に示すような温度分布に対応する変化を含む式となっている。ＢＴＰ推定部７では、風箱４の位置Ｐｉと排ガス温度Ｔｉを用いて（４）式に含まれるＡｉ、Ｂｉ、Ｃｉを求め、（４）式が極大値をとるＰ（実数）を算出し、それをＢＴＰ（焼成点）として推定する。

Where Ai: coefficient of quadratic term
Bi: coefficient of first-order term
Ci: Constant As described above, the estimated curve formula of the exhaust gas temperature is expressed by a quadratic function, and includes a change corresponding to the temperature distribution as shown in FIG. The BTP estimation unit 7 obtains Ai, Bi, and Ci included in the equation (4) using the position Pi of the wind box 4 and the exhaust gas temperature Ti, and calculates P (real number) where the equation (4) takes a maximum value. This is estimated as BTP (baking point).

  FIG. 4 is a diagram showing an example of a temporal transition of BTP estimated by the BTP estimation unit 7 in the configuration of FIG. 1, and shows a comparison with the conventional configuration. In this example, the number N of wind boxes 4 is 23, and represents the change in BTP within an elapsed time of 3 hours. In FIG. 4, the BTP estimated by the configuration of the present embodiment (indicated by the curve (A) in the figure) is more sensitive than the conventional case (indicated by the curve (B) in the figure). It is possible to capture changes. In the conventional configuration, the time change of the BTP could not be sufficiently captured, but in the configuration of the present embodiment, the first-order lag characteristic of the thermocouple 5 is compensated by the inverse filter 6, so that the measurement is performed. The response delay of the temperature is eliminated, and the BTP change can be identified with high accuracy.

  The BTP corresponding to the peak of the estimated curve of the exhaust gas temperature is not limited to the case of calculating by the formula (4), but a predetermined temperature set in advance in the range from the temperature rise position to the peak in the estimated curve formula of the exhaust gas temperature. The present invention can be applied even when the position to be obtained is calculated by the equation (4). For example, in the temperature distribution shown in FIG. 3, the position P at which the exhaust gas temperature is 300 degrees may be calculated.

  Next, returning to FIG. 1, the target value setting unit 8 sets a desired target value for BTP suitable for the operation of the sintering machine. For example, when the number N of wind boxes 4 is 23, the position of the 22nd wind box 4 close to the end of the effective captain can be set as the target value. In the target value setting unit 8, a suitable target value may be fixedly set in advance, but it may be set by appropriately switching the target value according to the operation state at that time by an external operation of the operator. .

  Next, the subtraction unit 9 subtracts the BTP value estimated by the BTP estimation unit 7 from the target value set by the target value setting unit 8 to obtain a deviation, and sends the deviation to the PID control unit 10. . Then, the PID control unit 10 obtains an operation amount that combines three of proportional control, integral control, and differential control so that the input deviation becomes small. Specifically, the PID control unit 10 performs an operation represented by the following equation (5) corresponding to the input signal X (s) and the output signal Y (s).

ただし、Ｋ ：比例項の定数
Ｋｉ：積分項の定数
Ｋｄ：微分項の定数
このように（５）式によって求めた出力信号Ｙ（ｓ）は、駆動モータ１１に供給される操作量となり、これにより駆動モータ１１における回転制御が行われる。駆動モータ１１においては、ＰＩＤ制御部１０からの操作量に適合する回転制御を行うことにより、適切なパレット速度を制御することができる。

Where K: constant of proportional term
Ki: Constant of integral term
Kd: Constant of differential term Thus, the output signal Y (s) obtained by the equation (5) becomes the operation amount supplied to the drive motor 11, and thereby the rotation control in the drive motor 11 is performed. In the drive motor 11, an appropriate pallet speed can be controlled by performing rotation control suitable for the operation amount from the PID control unit 10.

  Although the PID control unit 10 in the present embodiment realizes a basic control method, the effect of the present invention can be similarly achieved even when a known control method other than this is applied. Can do. For example, advanced control methods such as robust control and model predictive control may be employed.

  Next, the effect of the pallet speed control method according to this embodiment will be described with reference to FIGS. FIG. 5 is a diagram showing a temporal transition of BTP in the case of applying a pallet speed control method according to a conventional configuration in which the inverse filter 6 is not provided, and FIG. 6 is an application of the pallet speed control method according to the configuration of the present embodiment. It is a figure which shows the time transition of BTP in the case of doing. In each of the sintering machines configured with the number N of wind boxes 4 being 23, the change in BTP estimated by the equation (4) within the elapsed time of 3 hours is shown.

  As shown in FIG. 5, when the conventional pallet speed control method is applied, the estimated BTP fluctuation is distributed over a relatively wide range with time. On the other hand, as shown in FIG. 6, when the pallet speed control method according to the present embodiment is applied, the estimated BTP fluctuation is distributed in a narrower range than FIG. That is, since the true exhaust gas temperature is obtained by compensating the first-order lag characteristic of the thermocouple 5 by the inverse filter 6 provided in the present embodiment, and the BTP is calculated based on the result, the fluctuation of the BTP can be captured more sensitively. Can do. Since the pallet speed is controlled based on such BTP, the variation distribution of BTP can be limited to a narrow range.

  Here, as shown in FIGS. 5 and 6, the maximum value of the BTP fluctuation distribution was adjusted to 22.0. In this case, the average value of BTP is 21.7 in FIG. 5, and the average value of BTP is 21.9 in FIG. Thus, by adopting the pallet speed control method according to the present embodiment, since the fluctuation of the average value (center value) of BTP is reduced, it is possible to control the BTP closer to the excavation part. This improves the quality of the sintered ore obtained in the sintering machine and improves the productivity of the entire sintering process.

  In addition, in this embodiment, although the case where the thermocouple 5 was each installed in each wind box 4 of a sintering machine was demonstrated, this invention is applied even when it is a case where other temperature measuring means is installed. Can do. In addition, the time delay characteristic of the temperature measuring means is not limited to the first order delay characteristic, and the present invention can be applied even when the temperature measurement means has a higher order time delay characteristic within a range that can be compensated by the inverse filter 6. .

  When configuring the inverse filter 6, the BTP estimation unit 7, the target value setting unit 8, the subtraction unit 9, and the PID control unit 10 included in the embodiment described above, in addition to a method realized by a combination of digital circuits and the like, There is also a method that is realized by mounting and operating a program that functions integrally in a computer.

It is a figure which shows the structure of the sintering machine which concerns on this embodiment. It is a block diagram showing the structure of an inverse filter. It is a figure which shows an example of the temperature distribution of the waste gas in a sintering machine. It is a figure which shows an example of the time transition of BTP estimated by the BTP estimation part in the structure of FIG. It is a figure which shows the time transition of BTP in the case of applying the pallet speed control method by the conventional structure which does not provide an inverse filter. It is a figure which shows the time transition of BTP in the case of applying the pallet speed control by the structure of this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Surge hopper 2 ... Ignition furnace 3 ... Pallet 4 ... Wind box 5 ... Thermocouple 6 ... Inverse filter 7 ... BTP estimation part 8 ... Target value setting part 9 ... Subtraction part 10 ... PID control part 11 ... Drive motor 20 ... Sintering material

Claims (4)

A pallet speed control method in a sintering machine for controlling a pallet speed when supplying a sintering raw material onto a pallet of a sintering machine and transferring it to an exhausting section,
Measure the exhaust gas temperature at multiple locations in the machine length direction, compensate the time delay characteristics of the measured temperature with an inverse filter, estimate the relationship between the position in the aircraft length direction and the exhaust gas temperature based on the output of the inverse filter, and based on the estimation result A pallet speed control method in a sintering machine, wherein the pallet speed is controlled.   The exhaust gas temperature is measured by a plurality of temperature measuring means having a first-order lag characteristic, and the inverse filter has a characteristic represented by an inverse transfer function of the first-order lag characteristic. Pallet speed control method in a sintering machine.   In the sintering machine according to claim 1 or 2, wherein a peak in the estimated curve formula of the exhaust gas temperature is estimated as a firing point, and the pallet speed is controlled based on the estimated firing point. Pallet speed control method. 2. A position at which a predetermined temperature is set in advance in a range from a temperature rise position to a peak in the estimation curve formula of the exhaust gas temperature, and the pallet speed is controlled based on the estimation result. Or the pallet speed control method in the sintering machine of Claim 2.

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