RU2375659C1 - Automated control system of agglomerate quality - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention refers to automatic control system of agglomerate manufacturing and can be used in metallurgical industry for improvement of agglomerate. Automatic control system for agglomerate quality contains technological complex of agglomerate manufacturing, instrumentation facility, controlling mass consumption of material flows (charge, backoff and agglomerated cake), flow regulators of components of sintering mix, regulated feed drives, block of calculation of optimal control action. System additionally contains chemistry analyser of components of charge and agglomerate, block of calculation of corrected values of charge components consumption, backoff and agglomerated cake, calculation block of total content of non-controllable oxides in iron-ore part of charge, comparison block of calculated content of oxide in iron-ore part of charge with allowable value, defined in knowledge base by chemical composition of components of iron-ore part of charge, calculation block of corrected values of oxides content in iron-ore part of charge, calculation block of polynomials parametres, describing changes of components contains, forecasting block of agglomerate quality with usage of corrected values of mass consumptions and content of oxides in iron-ore part of charge.

EFFECT: improvement of agglomerate.

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Description

The invention relates to systems for automatic control of sinter production and can be used in the metallurgical industry to improve the quality of sinter.

Important mechanical quality criteria of the obtained agglomerate are its mechanical (strength) properties, which are judged by the data of the drum sample or by the amount of return allocated on the screen (Glinkov G.M., Makovsky AM ACS by technological processes in sintering and steel-making shops, Metallurgy, 1981, p. .52-65).

For the effective operation of the automatic control system of the agglomeration process, it is necessary to ensure the stabilization of all the main parameters that cause a change in the sintering speed of the charge.

The high quality of the sinter with the maximum productivity of the sinter machine can be achieved by completing the sintering process exactly at the end of the active length of the sinter. The moment of completion of the sintering process is determined by the temperature of the exhaust gases, their chemical composition, gas permeability of the charge layer on the tape, vacuum in vacuum chambers, illumination in the last two or three vacuum chambers (SU 973643, MKI C22B 1/16), magnetic permeability of the sintered layer (Fedorovsky N.V., Shanidze D.I. Agglomeration of iron ore. Kiev, Technique, 1991, p. 121-124, SU 1666558, MKI S22V 1/14).

The devices described above are characterized by the following disadvantages.

The practical implementation of the control used in them is hindered by the fact that gas sampling, its necessary cleaning from dust and moisture, as well as gas analysis, are relatively complex operations. When determining the gas permeability of the charge layer on the tape, it must be taken into account that the air filtration rate across the width of the sintering trolleys is not the same.

Existing systems for automatic control of the agglomeration process regulate the sintering process by changing individual control actions that are the tasks of local control systems.

A known system for optimizing the agglomeration process using a control computer complex (UVK) (M.G. Lodygichev, V.M. Chizhikova, V.I. Lobanov and others. Raw materials for ferrous metallurgy: Reference publication: in 2 volumes. 1. The raw material base and the production of agglomerated raw materials, M .: Mashinostroenie-1, 2001, p. 711), in which, along with local systems for regulating the moisture content of the mixture, the content of fuel, the height of the sintered layer, and the speed of the sintering belt, control agents are used impact on each of these regulators. These effects are generated as a result of the analysis of information received from sensors that monitor the sintering process.

Based on the information obtained, in the optimization system of the agglomeration process, control actions are developed to regulate the productivity of the charge supplied to the process, as well as corrective actions on the setpoints of local systems.

However, with such an integrated control system, it is difficult to solve the optimization problem due to the presence of a large delay in the measurement channels. So, for example, if you evaluate the strength of the agglomerate only by the amount of fines formed 0-5 mm in the drum sample, then between the moment the sintering process is completed and the moment the test results are obtained, about one hour passes (sampling the averaged sample, its delivery, testing and evaluation result by screening and weighing). Over such a period of time, the state of the sintering process under the influence of perturbing factors changes significantly, therefore, the recommendation obtained, for example, regarding the amount of fuel in the charge, or other quantities, becomes inappropriate for the changed process conditions.

Thus, in order to conduct the agglomeration process in the optimal mode, it is necessary to obtain operational information as quickly as possible on the degree of influence of various technological parameters at the moment on the agglomeration process (oxide content, moisture content of the charge, degree of pelletizing, charge consumption on the sinter strip, layer height on the sinter strip, sintering speed, sinter productivity, drum test data, return quantity and many others), i.e. it is necessary to predict the degree of influence of technological parameters on the agglomeration process.

A device for automatic control of the agglomeration process (Patent RU 2222614, MKI C22B 1/16), adopted as a prototype, comprising an agglomeration machine, an analyzer of particle size distribution of an agglomerate, a delay unit for particle size distribution of an agglomerate, a return flow sensor, a moisture content analyzer in a concentrate, a weight sensor is known charge; pelletizing power sensor; pelletizer charge; a unit for calculating the contributions of controlled disturbances; a unit for calculating the difference between the predicted and actual values of the output variables; unit for identifying model parameters, unit for calculating optimal control actions.

The disadvantage of this device is that it does not provide a procedure for calculating the adjusted values of the charge components, return and sintering, as well as a procedure for calculating the total content of uncontrolled oxides in the iron ore part of the charge. This leads to the fact that, due to errors in determining the mass flow rates of the charge components and their chemical composition, the material balance equations are not fulfilled, which are the basis for predicting the quality of the sinter.

The problem solved by the invention is to increase the accuracy of maintaining a given metallurgical quality of the agglomerate.

This problem is solved as follows.

A well-known automated system for controlling the quality of sinter, containing a measuring complex that controls the mass flow of the charge, return and sinter cake, a block of flow controllers for the components of the sinter charge, a block of adjustable feeder drives, a block for calculating optimal control actions, according to the invention is equipped with an analyzer of the chemical composition of the components of the charge and sinter, block of calculating the adjusted values of the flow rates of the components of the charge, return and sintering, block calculation of total soda neighing of uncontrolled oxides in the iron ore part of the charge, a unit for comparing the calculated content of oxides in the iron ore part of the charge with a permissible value determined in the knowledge base by the chemical composition of the components of the iron ore part of the charge, a unit for calculating the adjusted values of the content of oxides in the iron ore part of the charge, a unit for calculating parameters of polynomials describing changes component contents, sinter quality prediction unit using adjusted mass flow rates and content of oxides in the iron ore part of the charge, and the output of the measuring complex controlling the mass flow of material flows is connected to the input of the block for calculating the corrected flow rates of the components of the charge, return and sinter cake, the output of which is connected to the first input of the block for calculating the polynomial parameters, the output of the analyzer of the chemical composition of the components of the charge and the agglomerate is connected to the input of the unit for calculating the total content of uncontrolled oxides in the iron ore part of the charge, the output of which is connected to the first input of the unit to compare the calculated oxide content in the iron ore part of the charge with an acceptable value, and its second input is connected to the output of the knowledge base block of the chemical composition of the components of the iron ore charge, the output of the unit for comparing the calculated oxide content in the iron ore part of the charge with an acceptable value is connected to the input of the corrected value calculation unit the content of oxides in the iron ore part of the charge, the output of which is connected to the second input of the block for calculating the parameters of polynomials, the output of the block for calculating the parameters of the polynomial is connected nen quality prediction to the input block of agglomerate, sinter quality prediction block output is connected to the input of optimal control actions calculating unit; the output of which is connected to the input of the block of flow controllers of the components of the sinter charge; the output of which is connected to the input of the block of adjustable drives of feeders.

Thanks to the introduced blocks and connections, it is possible to predict the quality of the sinter taking into account the instability of the chemical composition of the charge.

The drawing shows a structural diagram of an automated sinter quality management system.

The automated sinter quality management system, interacting with the technological complex 1 for the production of sinter, consists of a measuring complex 2, which controls the mass flow of material flows (charge, return and sinter cake), block 3 of calculating the adjusted values of the flow of material flows, analyzer 4 of the chemical composition and humidity of the iron ore part charge (ZhRChSh), block 5, the calculation of the total content of uncontrolled oxides of XO in the iron ore part of the charge, block 6 of the knowledge base of chemical tava sinter mix components, which defines the allowable value of the content uncontrolled XO oxides ZHRCHSH, the comparison unit 7 calculated content CW oxides ZHRCHSH with an allowable value determined by the chemical composition of the components iron ore part of charge; block 8 of the calculation of the adjusted values of the content of oxides in the storage capacity ZhRChSh; block 9 for calculating the parameters of polynomials describing changes in the contents of the components, block 10 for predicting the quality of the sinter using the adjusted mass flow rates and the content of oxides in the liquid iron and steel, block 11 for calculating the optimal values of the control actions, block 12 for the flow controllers of the components of the sinter charge, block 13 for adjustable feeder drives.

The output of the measuring complex 2 is connected to the input of the block 3 for calculating the corrected flow rates of the charge, return and sinter components, the output of which is connected to the first input of the block 9 for calculating the polynomial parameters, the output of the analyzer 4 is connected to the input of the block 5 for calculating the total content of uncontrolled oxides in the iron ore part of the charge, the output of which is connected to the first input of block 7 comparing the calculated content of oxides in the iron ore part of the charge with a permissible value, and its second input is connected to the output of block 6 of the base the chemical composition of the components of the iron ore part of the charge, the output of block 7 is connected to the input of block 8 for calculating the adjusted values of the content of oxides in the iron ore part of the charge, the output of which is connected to the second input of block 9 for calculating polynomial parameters, the output of block 9 is connected to the input of block 10 for forecasting the quality of the sinter, the output of block 10 is connected to the input of block 11 for calculating optimal control actions; the output of which is connected to the input of the block 12 of the flow controllers of the components of the sinter charge; the output of which is connected to the input of the block 13 of adjustable feeder drives.

The technological complex 1 for the production of sinter is an agglomeration machine with component equipment.

As block 2, weight measuring devices are used.

As block 4, an analyzer of the chemical composition of the charge components is used, for example, a flow analyzer APUR “FERROKONT” conveyor version.

The FURROCONT APUR installation is intended for express, continuous quantitative control of the concentration of chemical elements in real time, directly on belt and plate feeders, conveyor belts.

Blocks 3, 5, 6, 7, 8, 9, 10, 11, 12 are implemented using a programmable controller, for example, the GE Fanuc controller, which polls the sensors and gives a control action to the drive, for example, AV300i.

The system operates as follows.

The mass flow rates of the charge, return, and sinter specimen measured in block 2 are sent to block 3. In block 3, the corrected flow values are calculated to ensure the minimum deviation of the measured values from the true values taking into account the material balance equations and control errors. The calculation is reduced to minimizing the amount of residuals weighted by the mean square errors of individual measurements:

subject to restrictions in the form of material balance equations

,

,

where x _i , x ^* _i - the measured and true value of the costs of the i-th stream, respectively;

η is the scale factor;

i = 1, 2, ..., n is the number of expenses to be determined;

m is the number of equations of material balance;

and _ij are the parameters of the equations;

σ _i - the root-mean-square error of measuring the flow rate by a specific weight meter.

λ(λ₁,,,,2_m) путем дифференцирования функции F(x, λ) по векторам x и λ и приравнивания получающихся уравнений нулю.Problem (1) under constraints (2) is solved by the method of indefinite Lagrange multipliers

λ (λ ₁ ,,,, 2 _m ) by differentiating the function F (x, λ) with respect to the vectors x and λ and equating the resulting equations to zero.

The function F (x, λ) has the form:

The resulting solution has the form:

where E _{n, n} is the identity matrix of dimension n * n;

C - diagonal matrix of dimension m * n with members:

A is the material balance matrix of dimension m * n with members and a _ij .

The chemical composition of the charge components measured in block 4 enters block 5. In block 5, based on the signals from the analyzer 4 of the chemical composition and humidity of the LRF, the total content of uncontrolled XO oxides in the LRF is calculated by the formula

where α _j is the content of oxides in LRF.

Block 6 contains a description of the laws that determine the chemical composition of the components of the iron ore part of the charge. Comparison of the calculated content of oxides XO _p in the iron ore with the permissible value of XO _D determined by the chemical composition of the components of the iron ore part of the charge in block 7 is made according to the formula

If the calculated value of the content of oxides XO _p exceeds the permissible value in the iron ore, the block calculates the adjusted chemical composition of the iron ore part of the charge and sinter components to ensure that the material balance equations are fulfilled while minimizing discrepancies in the content of metal, oxides, or other jx components:

when fulfilling restrictions on the equations of material balance

where i is the node number of the technological scheme;

n is the number of nodes;

j is the number of components;

m is the number of components;

s - node product number;

k _i2 , k _i2 - the number of products at the input and output of the i-th node;

α _sj is the content of metal, oxides or other jx components in the products;

ε _ijs are the errors in determining the content of metal, oxides or other jx components in the products for the s-th product of the i-th node of the technological scheme.

In block 9, according to the adjusted values of the mass flow rates and the contents of the components, the parameters of the polynomials are calculated, according to which the quality indicators of the sinter are forecasted

where r is the serial number of the element of the time series that describes the changes of the j-th component;

- фактическое значение показателя качества агломерата на r-м такте.

- the actual value of the quality indicator of the sinter at the r-th step.

In block 10, using the polynomials obtained in block 9, a forecast is generated for the change of the j-th component in the sinter by (r + d) clock cycles:

In block 11, according to the predicted value of the quality of the agglomerate, the values of the optimal control actions are generated, which are the tasks of the flow rate regulators of the components of the sinter charge in block 12. The tasks of the regulators by acting on the regulated drive of the feeders in the block 13 change the costs of the charge components, i.e. mode of operation of the technological complex.

Thus, thanks to the introduced blocks and connections, the quality management of the technological complex of sinter production is ensured.

Example. In the absence of a procedure for calculating the adjusted values of the charge components of the charge, return and sintering, as well as a procedure for calculating the total content of uncontrolled oxides in the iron ore part of the charge, the dispersion of the basicity of the sinter in the conditions of the sinter plant of the Magnitogorsk Iron and Steel Works is 0.0016, which is determined by the errors in estimating the costs of the charge components, return and sintering, as well as errors in assessing the chemical composition of the components of the charge. The simulation results of the system according to the invention show that thanks to the introduced blocks and bonds, the dispersion of the basicity of the agglomerate is reduced to a value of 0.0009. Thus, the relative variance characterizing the quality of management is 56% of the initial value.

Claims (1)

An automated sinter quality management system containing a measuring system that controls the mass flow of the charge, return and sinter cake, a unit for controlling the flow of components of the sinter charge, a block of adjustable feeder drives, a unit for calculating optimal control actions, characterized in that it is equipped with an analyzer of the chemical composition of the components of the charge and sinter , a unit for calculating the adjusted values of the costs of the components of the charge, return and sinter, a unit for calculating the total content uncontrolled oxides in the iron ore part of the charge, a unit for comparing the calculated content of oxides in the iron ore part of the charge with an acceptable value determined in the knowledge base by the chemical composition of the components of the iron ore part of the charge, a unit for calculating the corrected oxide content in the iron ore part of the charge, and a unit for calculating polynomial parameters describing changes in contents components, sinter quality prediction unit using adjusted mass flow rates and oxy content s in the iron ore part of the charge, and the output of the measuring complex that controls the mass flow of material flows is connected to the input of the block for calculating the corrected flow rates of the components of the charge, return and sinter specimen, the output of which is connected to the first input of the block for calculating the parameters of polynomials, the output of the analyzer of the chemical composition of the components of the charge and sinter connected to the input of the unit for calculating the total content of uncontrolled oxides in the iron ore part of the charge, the output of which is connected to the first input of the unit is connected inen with the first input of the unit for comparing the calculated content of oxides in the iron ore part of the charge with an acceptable value, and its second input is connected to the output of the unit of the knowledge base of the chemical composition of the components of the iron part of the charge, the output of the unit for comparing the estimated content of oxides in the iron part of the charge with an acceptable value is connected to the input unit for calculating the adjusted values of the content of oxides in the iron ore part of the charge, the output of which is connected to the second input of the unit for calculating the parameters of polynomials, the output of the unit for calculating p parameters of the polynomial connected to the input unit sinter quality, quality prediction block output prediction agglomerate connected to an input unit for calculating optimum control action, the output of which is connected to the input of the flow control valve components sinter mix with an output connected to an input unit controlled actuators feeders.