WO2012146059A1

WO2012146059A1 - Method using anode rod equidistant voltage drop to predict anode effect

Info

Publication number: WO2012146059A1
Application number: PCT/CN2012/000553
Authority: WO
Inventors: 杨晓东; 周东方; 马恩杰; 张钦菘; 符勇; 殷小宝
Original assignee: 中铝国际工程股份有限公司
Priority date: 2011-04-29
Filing date: 2012-04-25
Publication date: 2012-11-01
Also published as: CN102758219A; CA2834292A1; CN102758219B; NO20131581A1; NO347531B1; CA2834292C

Abstract

A method using anode rod equidistant voltage drop to predict anode effect comprises the following steps: an anode rod equidistant voltage drop sensor is mounted on each anode rod of a prebaked anode electrolytic cell, said anode rod equidistant voltage drop sensor transmitting the collected anode rod equidistant voltage drop signal to a front end data analyzer; the front end data analyzer analyzes and processes the anode rod equidistant voltage drop data, identifies anodes for which there is an impending anode effect, and transmits the prediction results to the electrolytic cell control machine. Malfunctioning anodes are effectively monitored by means of targeted prediction of the anode effect on each anode in the electrolytic cell, thereby allowing for precision operation of the electrolytic cell, which in turn promotes stable electrolytic cell operations, saves energy and improves current efficiency.

Description

Method for predicting anode effect by using anode guide rod isometric pressure drop

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a method for predicting the anode effect using an isobaric pressure drop of an anode guide rod, and more particularly to predicting an individual anode that is about to have an anode effect in a prebaked anode aluminum electrolytic cell using an isolating pressure drop data of the anode guide rod of the electrolytic cell.

Background technique

The conventional anode effect prediction method of the electrolytic cell is based on the analysis of the voltage signal of the entire electrolytic cell, and the anode effect of the electrolytic cell is predicted based on the signal size of the overall cell voltage. However, in actual production, the anode effect occurs first on individual anodes. In recent years, as the size of the electrolytic cell has become larger, the shortcomings of the conventional anode effect prediction method have been exposed. The original method of predicting the anode effect by the overall cell voltage can only determine that the anode effect is about to occur in the entire tank, and it is impossible to determine the specific region where the anode effect is about to occur. The method used to suppress the anode effect can only be used for all the feed ports simultaneously. For the large blanking, the blanking method changes the concentration of alumina in the electrolyte, making it uneven in spatial distribution and increasing the consumption of alumina. This conventional anode effect prediction method, which does not consider the specific anode difference, has been unable to meet the requirements for the fine operation of the new electrolytic cell, nor does it meet the current goal of reducing the energy consumption of the aluminum electrolytic process. The new accurate positioning of the anode effect prediction method is very important to further improve the technical and economic indicators of the aluminum electrolytic cell.

Summary of the invention

In order to solve the above technical problems, the present invention provides a method for predicting an anode effect by using an anode guide rod equidistant pressure drop, the purpose of which is to accurately position an individual anode for an impending anode effect, and to locate an area where an anode effect is to occur, to satisfy the electrolysis. The requirements for the fine operation of the tank. The method comprises the following steps: installing an anode guide rod equidistant pressure drop signal sensor on the anode guide rod of the prebaked anode electrolysis cell, and the anode guide rod isometric pressure drop signal sensor will collect the anode anode rod equidistant pressure drop The signal is sent to the front-end data analyzer; the front-end data analyzer analyzes and processes the anode guide rod isometric pressure drop data, predicts the anode that is about to have an anode effect, and sends the predicted result to the electrolytic cell slot control machine. The pretreatment of the anode guide rod isometric pressure drop data, low-pass filtering the processed anode guide rod isometric pressure drop data, and the obtained low-pass filter data are respectively subjected to high-frequency needle shock processing, slope processing, and Cumulative slope processing, high frequency needle shock processing, slope processing, and cumulative slope processing

The rod, the raw data of the anode guide rod isometric data with a length of ί is taken for data preprocessing; the processing method adopts the following smoothing formula to remove the abnormal needle vibration in the signal, and the formula is as follows:

y _M =― (2^,- ₂ - 8 —, + 12 . + 27 ₊₁ + 2y ₁₊₂ ) y, ₊ 2 = - 6 + 4y _M + 69y _i+2 )

Where is the smooth value of ^, ^ is the original data acquisition value, and the first two points and the last two points of the data are calculated using only the first, second, fourth, and fifth formulas in the above formula group, respectively.

The low-pass filtering of the processed anode guide rod isometric pressure drop data refers to the use of Butterworth bilinear filtering, and the filter frequency upper limit is defaulted to l/600 Hz.

The high-frequency needle-shock processing of the obtained low-pass filter data separately refers to dividing the time length t into 5 equal parts, and calculating the intensity of the anode-guided isometric pressure-dropping shock intensity in each cycle according to the following formula. The formula is as follows: shake^ ^^—^—^FW—T^— ;

Then, the shock intensity of each time period is smoothed by the following formula; Shake' (k) = 0.75 * Shake(k - 1) + 0.25 * Shake(k) ' where k = { 1, 2, 3, 4 , 5}; then in the current prediction period, the intensity of the needle shock is _max0%ayte ' _w ); where ^ ^, ^ „ is the maximum value of the isometric pressure drop of the original anode guide in each equalization period And the minimum value, F is the equidistant pressure drop of the anode guide rod that has been low-pass filtered in each equalization period. The slope of the pressure drop is the anode guide rod equidistant pressure after low-pass filtering in the period of the prediction period t The average rate of change of the drop; also the time length t is divided into 5 equal parts, then the slope of the anode pressure guide isometric formula for the period t is:

Slope(t) = (VF(k - 1) - VF{k - 3) + 2(VF(k) - VF{k - 4))) / 5.

The cumulative slope processing of the obtained low-pass filter data is calculated by the following formula:

Lslope(t) = (7 / 8) * Lslope(t-1) + 2 * Slope{t) 13

Lslope(0) = Slope(0) °

The data after the high frequency needle shock processing, the slope processing and the cumulative slope processing are subjected to the anode effect discrimination processing to set the threshold for the slope, the cumulative slope and the high frequency needle shock, if the cumulative slope of the anode guide rod is equal to the cumulative pressure drop The cycle is continuously decreased, the anode guide rod isometric pressure drop, the slope of the cycle is greatly reduced, or the anode guide rod isometric pressure drop high-frequency needle vibration is greatly increased, and the anode effect is determined to be about to occur.

Advantageous Effects of the Invention: The invention can specifically predict the anode effect of each single anode of the electrolytic cell, effectively monitor the abnormal anode, realize the fine operation of the electrolytic cell, and be beneficial to stabilize the electrolytic cell. Operation, to achieve energy saving, improve current efficiency.

Lifting implementation

The invention utilizes the method for predicting the anode effect by the anode guide rod isometric pressure drop, comprising the following steps: installing an anode guide rod equidistant pressure drop signal sensor on each anode guide rod of the prebaked anode electrolysis cell, the anode guide rod isometric The pressure drop signal sensor transmits the collected anode guide rod isometric pressure drop signal to the front end data analyzer; the front end data analyzer analyzes and processes the anode guide rod isometric pressure drop data to predict the anode that is about to have an anode effect, The prediction result is sent to the electrolytic cell tank, and the pre-treatment of the isolating pressure drop data of the anode guide rod in the machine, the low-pass filtering of the processed anode guide rod isometric pressure drop data, and the obtained low-pass filter data The high-frequency needle shock processing, the slope processing, and the cumulative slope processing are performed separately, and the data after the high-frequency needle shock processing, the slope processing, and the cumulative slope processing are subjected to the anode effect discrimination processing.

The pre-treatment of the anode guide rod isometric data is to pre-process the raw data of the anode guide rod equidistant pressure drop for each anode guide rod of the electrolytic cell, and the processing method adopts the following smoothing formula. To achieve the removal of abnormal needle vibration in the signal, the formula is as follows: y,-i =— (69^_ ₂ +4 — ₁ _6 +4y _M - y, ₊₂ ) — ¹ = ^( ² ;'— ^{2 + 27} ^ ^{+ 12} ^ — ⁸ ₊₁ +2 ₊₂ )

y, = (-3^ +12^, +17 , +\2y _M -3y _i+2 y _1+l 12 . +2Ty _M +2 ₊₂ ) y, ₊ 2

- 6 + +, + 69y _i+2 ) where is the smooth value, the original data is collected, the first two points and the last two points of the data are only used in the first, second and fourth, respectively, in the above formula group The low-pass filtering of the anode guide rod isometric pressure drop data after the pairing and processing is performed by means of Butterworth bilinear filtering, and the filter frequency upper limit is defaulted to l/600 Hz.

The high-frequency needle-shock processing of the obtained low-pass filter data separately divides the time length t into 5 equal parts, and calculates the equidistant pressure drop intensity of the anode guide rod in each period t according to the following formula, and the formula is as follows : _{shake w} = ― _Vmm -\VF _{k) - VF{k -1)|;

The needle shock intensity over each time period is then smoothed as follows: Shake' (k) = 0.75 * Shake{k - 1) + 0.25 * Shake(k) ' where k = {1,2,3,4 , 5}; then the needle shock intensity in the current prediction period t is _max0%ateW ); where ^ _min is the maximum and minimum values of the equidistant pressure drop of the original anode guide in each equalization period, The low-pass filtered anode lead is equally spaced in each equalization period.

The slope processing of the obtained low-pass filter data respectively refers to the average rate of change of the equidistant pressure drop of the anode guide rod after the low-pass filtering in the period of the prediction period t; / The average is divided into 5 equal parts, then the period, the slope of the anode anode guide isometric pressure drop is calculated as:

Slope(t) = (VF(k - 1) _ VF(k - 3) + 2(VF(k) - VF(k - 4))) / 5

Lslope(t) = (7 / 8) * Lslope(t - 1) + 2 * Slope(i) 13

Lslope(0) = Slope(0)

The data after the high frequency needle shock processing, the slope processing, and the cumulative slope processing are passed through The anode effect discrimination processing refers to setting the threshold value for the slope, the cumulative slope and the high-frequency needle shock. If the cumulative slope of the anode guide rod is continuously decreasing for several consecutive periods, the slope of the anode guide rod is significantly decreased or the anode is inclined. The high-frequency needle vibration of the guide rod isometric pressure drop is greatly increased, and the anode effect is determined to be about to occur.

Claims

Rights request

1. A method for predicting an anode effect by using an anode guide rod isometric pressure drop, comprising: a signal sensor, an anode guide rod isometric pressure drop signal sensor conveying the collected anode rod equidistant pressure drop signal to a front end data analyzer; The front-end data analyzer analyzes and processes the anode guide rod isometric pressure drop data, predicts the anode that is about to have an anode effect, and sends the predicted result to the electrolytic cell slot control machine.

2. The method for predicting an anode effect using an anode guide rod equidistant pressure drop according to claim 1, wherein the front end data analyzer analyzes and processes the anode guide rod isometric pressure drop data, including: Pre-processing of the equidistant pressure drop data of the rod, low-pass filtering the processed anode guide rod isometric pressure drop data, and performing the high-frequency needle shock processing, slope processing and cumulative slope processing respectively on the obtained low-pass filter data, The data after the frequency needle shock processing, the slope processing, and the cumulative slope processing are subjected to the anode effect discrimination processing.

3. The method for predicting an anode effect using an anode guide rod equidistant pressure drop according to claim 2, wherein said pre-treatment of the anode guide rod equidistant pressure drop data is for each anode guide rod of the electrolytic cell. The data is preprocessed by the original data of the anode guide rod with the length of time t of the intercepting time; the processing method adopts the following smoothing formula to remove the abnormal needle vibration in the signal, and the formula is as follows: y, - ₂ =― (69 ^,_ ₂ + 4 — , - 6 + 4y _M ― +2 , —, =^(2 — ₂ +27y,_ ₁ +12 8 ₊₁ +2y _i+2 )

y, = ^(― 3 _ ₂ + 12y, _, +17j, +l 2y _M ― 3y _i+2 )

y _M = (2 - ₂ -8^, +12 +27y _M +2y _i+2 )

Where is the smooth value, which is the original data acquisition value. The first two points and the last two points of the data are calculated using only the first, second and fourth, and fifth formulas in the above formula group.

4. The method of predicting an anode effect using an anode guide rod equidistant pressure drop according to claim 2, Filtering refers to the use of Butterworth bilinear filtering, the filter frequency upper limit defaults to l/600Hz.

5. The method for predicting an anode effect by using an anode guide rod with an equidistant pressure drop according to claim 2, wherein said obtaining low-pass filter data for high-frequency needle-shock processing respectively means that a length of time t is Divided into 5 equal parts, calculate the equidistant pressure drop intensity of the anode guide rod in each period t according to the following formula, the formula is as follows: shake - ^ - _m∞ - 1) |; Then press the following for each time period The needle shock intensity is smoothed; Shake (k) = 0.75 * Shake(k - 1) + 0.25 * Shake(k) ' where k = { 1 , 2, 3, 4, 5}; then in the current prediction period t The internal shock intensity is _max0%afe '); where ^^ _mm is the maximum and minimum values of the equidistant pressure drop of the original anode guide in each equalization period, which is within each equalization period. The low-pass filtered anode guide is equally spaced.

6. The method for predicting an anode effect by using an anode guide rod equidistant pressure drop according to claim 2, wherein said separately performing low-pass filter data for slope processing refers to an anode guide rod isometric pressure drop slope. In order to predict the average rate of change of the equidistant pressure drop of the anode guide rod after low-pass filtering in the period t period; also divide the time length t into 5 equal parts, then the period, the anode anode guide rod isometric pressure drop The slope calculation formula is:

Slope(t) = (VF(k - 1) - VF(k - 3) + 2(VF(k) - VF(k - 4)))) / 5.

7: The method for predicting an anode effect using an anode guide rod pressure drop according to claim 2, wherein said separately performing low-pass filter data for cumulative slope processing is calculated by the following formula:

Lslope(t) = (7 / 8) * Lslope(t - 1) + 2 * Slope{t) 13

Lslope(0) = Slope(0).

8. The method for predicting an anode effect using an anode guide rod equidistant pressure drop according to claim 2, wherein said high frequency needle shock processing, slope processing, and accumulated slope processing data are subjected to anode effect discrimination processing. It means that the slope, the cumulative slope and the high-frequency needle shock are set to a wide value. If the cumulative slope of the anode guide rod is continuously decreased for several consecutive periods, the anode guide rod is equally reduced in slope, or the anode guide is equidistant. When the voltage drop high-frequency needle vibration is greatly increased, it is determined that the anode effect is about to occur.