Furnace Control System Research Articles

Systematic Research and Optimization Design of Intelligent Electric Furnace Control System

Systematic Research and Optimization Design of Intelligent Electric Furnace Control System

Development of technology for the production of heat-insulating materials for use in metallurgy and mechanical engineering

The article considers the tasks of metallurgical, machine-building, and foundry enterprises of Ukraine regarding heat saving in these industries during the war and post-war periods and in the future. It is shown that the possibilities of developing heat and energy saving in metallurgy and machine building through the widespread use of effective heat-insulating materials made of multisilica fibre have not been fully realised in practice. A promising area of application of heat-insulating products is the construction, reconstruction and modernisation of existing metallurgical units in blast furnace, steelmaking and rolling sections. The technology for the production of modern heat-insulating materials made of multisilica fibre, which are efficient at temperatures up to 1600 °C, sometimes even higher, has been developed and put into practice. Possibilities of changing the operating temperature of products made of multisilica materials (cotton wool, felt, plates, felt, cardboard, etc.) by varying the content of aluminium, chromium, zirconium compounds in the charge for smelting multisilica materials are shown. Specific technical solutions to save energy are proposed, which allow reducing the cost of heating furnaces by ~ (40...45) % by using thermal insulation made of multisilica fibre. The experience of the SINTIZ LLC plant regarding the measures taken to modernise the SKB 6098 ore-thermal furnace is presented. As a result of the improvement of the furnace control system, electricity consumption decreased by ~ (5...15) %. The direction of further modernisation of multisilica fibre production is to combine separate local process control systems into a single closed automated control system for the production of this product. Research and development activities aimed at improving the technology for the production of heat-insulating materials and products based on the use of natural raw materials are also relevant.

Innovative ore-thermal furnace control systems

The relevance of this topic can be justified with poor automation of the ore-thermal furnace process — in particular, the one involved in the production of metallurgical silicon. The majority of process control systems enable centralized acquisition of available data. Such approach can cause certain issues as some data can arrive with a big delay or can be irrelevant to the reaction zone but rather serve to monitor separate components of the furnace. The lack of reliable real-time information forces operators to make decisions based on their experience, which often leads to inefficient operation introducing the risk of human error and, consequently, that of emergency. Such operation often leads to overconsumption of electric power, high consumption of graphite electrodes and can cause dust discharge. Control of the basic furnace parameters based on indirect parameters and the use of process model-based controllers offer innovative areas in the development of ore-thermal furnace process control systems. Improving the obser vability of the object of control remains a relevant problem. It can normally be achieved by implementing new controlled parameters in a monitoring or control system. This paper describes the most innovative control systems that enable to monitor the process parameters and control the power mode of an ore-thermal furnace. The paper reviews two articles, eleven patents and five computer programmes that have the biggest potential of industrial implementation.This research was funded through Governmental Research Grant no. FSRW-2020-0014 for 2021 and Russian Science Foundation, Grant № 22-29-003.

Адаптивный регулятор мощности индукционной тигельной печи с проводящим ферромагнитным тиглем

A structural model of a high-frequency induction crucible furnace with a conducting ferromagnetic crucible is developed in the Simulink/Matlab environment based on investigations carried out by the authors. The inductor current was calculated using the inductor's resistance and inductance dependences on temperature, frequency, and current. An induction crucible furnace power control system structural model is designed based on the developed model. The output voltage pulse-frequency modulation is used as a furnace power control method. An adaptive power controller for the induction crucible furnace with a conducting ferromagnetic crucible is developed, which includes two channels for control of the power supply source frequency and voltage. It has been determined that the melting with the lowest energy expenditures is obtained in the case of using a power controller with two different adaptive control structures. The controller operates based on the frequency control principle and uses structures depending on the current temperature value. The use of the adaptive power controller with two control channels can significantly reduce the specific electric energy consumption in comparison with automatic frequency adjustment, in particular, by a factor of 1.45 for the IGT-1.6M industrial furnace.

Optimization of Non-Stationary Electric Field Parameters in Order to Increase the Efficiency of Chamber Furnaces

Topicality. The presented work is devoted to the urgent task of increasing the energy efficiency of chamber furnaces.The purpose is to solve the problem connected with optimizing the parameters of the non-stationary mode of the applied electric field in order to increase the efficiency of the chamber furnaces. Methodology. According to well-known methods of experiment planning, we obtained a set of Pareto-incomparable solutions of the chamber furnace, taking into account the voltage between the burner and the metal charge, which is the basis of the algorithm. Findings. The work proposes an innovative system acting the process of metal heating in a chamber furnace. The result is a developed chamber furnace control system, in which the optimal values of control actions at each step of the heating cycle are determined according to the created algorithm. The proposed control system is universal, because after miscalculations it produces the dynamics, according to which one needs to change the value of direct-current voltage and gas supply with a step in time to perform any given mode of metal heat treatment. The experimental studies conducted on a real chamber furnace with a bogie hearth at Zaporozhye Titanium and Magnesium Combine confirmed this. The analysis of the obtained metal annealing temperature curve showed that the implementation of the optimal values of the control actions, obtained using the developed algorithm, provides a high uniformity and better quality heating of the metal. The dynamics of gas consumption by the chamber furnace during the heating cycle in the basic mode, without voltage supply, and under the condition of its use in accordance with the performed optimization testify to the possibility of significant energy efficiency improvement of the considered furnaces. Conclusions. For the first time we proved the possibility and efficiency of using a non-stationary electric field in the furnace chamber as a control action, which confirms the originality of the obtained results. The practical value of the research is that the developed control algorithm is universal in terms of metal heat treatment and can be used in chamber furnaces of any industrial enterprise, while one heating cycle reduces the consumption of natural gas by more than 10 %.

Automatic Gas fired furnace

The essence of any Foundry is its furnace. The operation of the furnace legally involves the process of melting metal by hand is highly dependent on human performance as well ability. With increasing demand and improved technology, this is a common approach it is quickly replaced by temperature-controlled libraries. Basic the effectiveness of such a control to compare the temperature of the metal with the set melting temperature and send the corresponding output to the heat or heat feature. The type of temperature and the furnace customize the type of controller used. While such a control system exists, other safety and fuel management controls plans are the essentials of a modern day oven. This paper is intended in the construction of such a gas burner control system. Gas exploded Furnace Control System includes an active Burner Management System a large part of the melting process. The Control system is built with emphasis on Flame Feedback method, which was analyzed in detail. The control system is actually a temperature control system which includes sensor inputs including thermocouple and flame rod, and effects such as large gas valve, heat rod and blower fan motor. Thus this system is aimed at proper burner management that facilitates the furnace operation and ensures safety of not only the furnace-burner system but the plant in general.

RESEARCH OF ARC FURNACE ELECTRICAL MODE WITH A FUZZY CONTROL MODEL

Goal. The purpose of the paper is to increase the efficiency of arc steelmaking furnace (ASF) operating modes control basing on the improvement of arc lengths control model. Method. The control model is based on the fuzzy set theory, and the structural modelling methodology is used to study the dynamics indices. Results. The structural scheme of a furnace arc lengths fuzzy control system and the electrical mode (EM) coordinate control dynamics parameters values in response to the deterministic and random arc lengths fluctuations were obtained. Scientific novelty. For the first time, a fuzzy model of an EM mismatch signal generation with operational adaptation to its current state in each phase was developed, which enabled by-phase independent control of arc lengths and improved energy efficiency. Practical value. Dynamic accuracy of EM coordinates stabilization at the setpoint level is improved, in particular the arc currents dispersion is reduced, which leads to a corresponding power loss decrease in arc furnace short network, an increase of the furnace productivity, as well as to an improvement of the electromagnetic compatibility of the arc furnace and power supply network.

Environmental performances of a modern waste-to-energy unit in the light of the 2019 BREF document

The study compares the environmental performances of a new-generation, large scale, combustion-based waste-to-energy unit, active since 2010, with those of different “virtual” units, defined in the light of the Best Available Techniques REFerence document (BREF) for Waste Incineration published by the European Community on December 2019. The average performances of these units have been evaluated in terms of air emissions, material consumptions and energy recovery, based on data related to 355 “existing” European waste incineration lines and those established for the future “new” plants. An attributional Life Cycle Assessment has been used to compare and quantify the environmental performances of the selected units, all equipped with a moving grate furnace and similar air pollution control systems. A sensitivity analysis quantifies how even more severe requests for emission and energy performances as well as the evolution of the European electricity mix until the year 2030 can affect the comparative assessment. The results indicate that the considered large scale waste-to-energy plant has good environmental performances, even in an electricity mix characterised by 45% of renewable sources. This allows an easy compliance with the Best Available Techniques Associated Emission Levels of the new waste incineration BREF document. Possible further improvements of its performances should be focused mainly on a further increase of the energy efficiency, provided that it is economically viable.

Модель для прогнозирования температуры заготовки по ретроспекции ее нагрева на основе бустинга структуры «случайный лес»

The scope of this research is the prediction of a cast billet surface temperature, which it will have in the rolling mill after the heating process. The main problem is that such a prediction is needed before the cast billet will really leave the furnace. In many cases, the boundary value problem of the heat transfer, particularly the differential equations of the transient heat conduction, is used to solve this problem. But in this research an alternative data-driven approach is proposed, which is based on a model of the dependence of the billet temperature on the retrospection of its heating in the continuous furnace. Such a model is developed as a result of the analysis of the data from the furnace control system. Such data from the real furnace were collected and stored in the data warehouse. Their exploratory analysis was conducted. All data were splitted into training, testing and validation subsets. As a part of this research, the regression model previously developed by the authors was also validated. It seemed to be overfitted (the error on the test set was significantly higher than the one on the training set). To overcome this disadvantage, an alternative method to develop the required data-based model is proposed by authors on the basis of the Boosting and Bagging algorithms. They belong to the machine learning field. As a result of the experiments with the bagging and boosting, the required model structure was chosen as a “Random Forest” with special class of the regression trees known as DART (Dropout Adaptive Regression Trees). Based on a significant number of experiments with that model, the two confidence intervals of the temperature prediction were found: 68 % and 95 % ones. The mean value of the temperature prediction error was estimated as ~ 9 °C for both the test and validation sets.

The Method of Efficiency Definition of New Functional Task in Electric Arc Furnace Control System

Abstrast. The task of the study is to create the measures and methods of efficiency definition of new functional task in electric arc furnace control system. The method of system analysis was applied. The research was carried out in the shops of Magnitogorsk Iron and Steel Works (MMK). Method of efficiency definition of new functional task module in electric arc furnace control system was developed. The capacity loading reduction of bucket quantity and materials in charging process in the electric arc furnace for any planned task was presented.

Parameters Optimization of the Heating Furnace Control Systems Based on BP Neural Network Improved by Genetic Algorithm

The heating technological requirement of the conventional PID control is difficult to guarantee which based on the precise mathematical model, because the heating furnace for heating treatment with the big inertia, the pure time delay and nonlinear time-varying. Proposed one kind optimized variable method of PID controller based on the genetic algorithm with improved BP network that better realized the completely automatic intelligent control of the entire thermal process than the classics critical purporting (Z-N) method. A heating furnace for the object was simulated with MATLAB, simulation results show that the control system has the quicker response characteristic, the better dynamic characteristic and the quite stronger robustness, which has some promotional value for the control of industrial furnace.

Operational Semantics of Annotated Reflex Programs

Reflex is a process-oriented language that provides a design of easy-to-maintain control software for programmable logic controllers. The language has been successfully used in a several reliability critical control systems, e. g. control software for a silicon single crystal growth furnace and electronic equipment control system. Currently, the main goal of the Reflex language project is to develop formal verification methods for Reflex programs in order to guarantee increased reliability of the software created on its basis. The paper presents the formal operational semantics of Reflex programs extended by annotations describing the formal specification of software requirements as a necessary basis for the application of such methods. A brief overview of the Reflex language is given and a simple example of its use – a control program for a hand dryer – is provided. The concepts of environment and variables shared with the environment are defined that allows to disengage from specific input/output ports. Types of annotations that specify restrictions on the values of the variables at program launch, restrictions on the environment (in particular, on the control object), invariants of the control cycle, pre- and postconditions of external functions used in Reflex programs are defined. Annotated Reflex also uses standard annotations assume, assert and havoc. The operational semantics of the annotated Reflex programs uses the global clock as well as the local clocks of separate processes, the time of which is measured in the number of iterations of the control cycle, to simulate time constraints on the execution of processes at certain states. It stores a complete history of changes of the values of shared variables for a more precise description of the time properties of the program and its environment. Semantics takes into account the infinity of the program execution cycle, the logic of process transition management from state to state and the interaction of processes with each other and with the environment. Extending the formal operational semantics of the Reflex language to annotations simplifies the proof of the correctness of the transformation approach to deductive verification of Reflex programs developed by the authors, transforming an annotated Reflex program to an annotated program in a very limited subset of the C language, by reducing a complex proof of preserving the truth of program requirements during the transformation to a simpler proof of equivalence of the original and the resulting annotated programs with respect to their operational semantics.

An adaptive PID controller with an online auto-tuning by a pretrained neural network

This paper describes an intelligent adaptive PID controller design procedure. The controller consists of a discrete time PID and an auto-tuning neural network unit. First system identification with a nonlinear autoregressive model (NARX) was performed. This model was then used to train the neural PID tuner. A special MATLAB toolbox “SmatPID Toolbox” was developed to automate the process of controller synthesis. The resulting controller was tested in a laboratory coal-gas furnace control system to track specified air flow rates.

Advanced systems for heat treatment controlling of electrical furnaces

This paper presents a modern electric heat treatment which has implemented an electric furnace control system through thermoregulatory with PID control laws. An important aspect is the development of a mathematical model for controlling electrical heating systems for heat treatments based on mathematical modelling to predict the mechanical properties and structure of the play resulting from heat treatment. Validation of the experimental research of heat treatment designed by the mathematical model for predicting mechanical properties and structure of the finished part and model for controlling electrical heating system based on PID adjustment algorithms consists in structural analysis to determine the chemical composition, structural analysis by light microscopy, electron microscopy SEM and EDX quantitative analysis, determination of hardness alloys and physical and mechanical of the turbine blades component of a plasma torch on hydrogen made of heat-treated steel.

Nonlinear dynamic simulation and control of large-scale reheating furnace operations using a zone method based model

Modern reheating furnaces are complex nonlinear dynamic systems having heat transfer performances which may be greatly influenced by operating conditions such as stock material properties, furnace scheduling and throughput rate. Commonly, each furnace is equipped with a tailored model predictive control system to ensure consistent heated product quality such as final discharge temperature and temperature uniformity within the stock pieces. Those furnace models normally perform well for a designed operating condition but cannot usually cope with a variety of transient furnace operations such as non-uniform batch scheduling and production delay from downstream processes. Under these conditions, manual interventions that rely on past experience are often used to assist the process until the next stable furnace operation has been attained. Therefore, more advanced furnace control systems are useful to meet the challenge of adapting to those circumstances whilst also being able to predict the dynamic thermal behaviour of the furnace. In view of the above, this paper describes in detail an episode of actual transient furnace operation, and demonstrates a nonlinear dynamic simulation of this furnace operation using a zone method based model with a self-adapting predictive control scheme. The proposed furnace model was found to be capable of dynamically responding to the changes that occurred in the furnace operation, achieving about ±10 °C discrepancies with respect to measured discharge temperature, and the self-adapting predictive control scheme is shown to outperform the existing scheme used for furnace control in terms of stability and fuel consumption (fuel saving of about 6%).

МЕТОДЫ ВЫБОРА РАЦИОНАЛЬНОГО СОСТАВА ДОМЕННОЙ ШИХТЫ

The aim of the work is to solve the problem of choosing the optimal composition of iron ore materials for blast furnace loading. An analytical review of the existing approaches to assessing the quality and methods for selecting a rational composition of iron ore materials implemented as part of the control system of domestic and foreign blast furnaces in modern conditions has been carried out. A method of modeling the processes of directional formation of melts, developed at the Iron and Steel Institute, is proposed. The description of the processes of transformation of iron ore materials in a blast furnace and the properties of liquid smelting products was carried out using the parameters of interatomic interaction in melts. The technique uses a set of integral criteria and physicochemical models that allow estimating charge, gas-dynamic and temperature melting conditions. The influence of the quality of iron ore on the properties of primary melts and final products of blast-smelting is analyzed. An integral indicator of the quality of the charge and an integral indicator of the temperature blast mode have been developed. The main difference of the proposed approach to the selection of the composition of the charge from similar developments focused on the traditional criterion «basicity of the final slag» is the use of a set of physico-chemical criteria that characterize the quality and properties of iron ore, primary and final blast furnace slag. The use of the developed prognostic models and criteria as part of automated blast furnace control systems allows us to predict the chemical composition of iron and slag. Stabilization of slag properties within the specified limits ensures the smelting of cast iron of the required composition and a reduction in coke consumption in the current unstable conditions of smelting iron.

A new approach for estimation of total heat exchange factor in reheating furnace by solving an inverse heat conduction problem

The estimation of the total heat exchange factor plays an important role while obtaining the reference trajectories on steady-state furnace operation for the reheating furnace control system. For this purpose, this paper presents a new optimization method to estimate the total heat exchange factor by solving the inverse heat conduction problem (IHCP) in the reheating furnace. The proposed method is based on the Conjugate Gradient Method (CGM), the Levenberg-Marquardt Algorithm (LMA) and Gradient Projection method (GPM). In the proposed method, CGM is introduced for its fast convergence speed and the high accuracy, LMA is employed to assure the convergence of iteration sequence, and GPM is guaranteed to identify the active set at a solution in a finite number of iterations. The experiment results using the real plant data measured by thermocouples and the comparison between the proposed method and CGM are discussed. The results show the effectiveness on overcoming oscillation manner by the proposed approaches.

Development and Implementation of New Measuring and Monitoring Systems to Support BF Control

For optimal blast furnace control, suitable measurement and monitoring systems are required. This paper focuses on the development and implementation of three new measurement devices and methods at ROGESA in Dillingen: 1) sonic gas temperature measurement, 2) a camera-based monitoring system at tuyere level, and 3) EMF and strain gauge measurement to determine the liquid level in the hearth of the blast furnace. These measurement and monitoring systems have been installed and successfully tested in the recent years. The information obtained is used to optimize the furnace control for enhancing the BF performance.

Lowcost automated control for steel heat treatments

The aim of this paper is to propose a low cost, automated furnace control system for the heat treatment of steel. We used an open source electronic prototyping platform to control the furnace temperature, thus reducing human interaction during the heat process. The platform can be adapted to non-controlled commercial furnaces, which are often used by small businesses. A Proportional-Integral-Derivative (PID) controller was implemented to regulate the furnace temperature based on a defined heat treatment cycle. The embedded system activates the furnace resistors through Pulse Width Modulation (PWM), allowing for control of electrical power supplied to the furnace. Hardening and tempering were performed on standard steel samples using a traditional method (visual inspection without temperature control) as well the embedded system with PID feedback control. The results show that the proposed system can reproduce an arbitrary heat treatment curve with accuracy and provide the desired final hardness as inferred through metallographic analysis. In addition, we observed a 6% saving in energy consumption using the proposed control system. Furthermore, the estimated cost to implement the system is 42% lower than a commercial controller model implemented in commercial furnaces.

Principles of the Development and Introduction of an Automated Process Control System for Blast-Furnace Smelting at the Magnitogorsk Metallurgical Combine

The principles of construction and the architecture of an automated system for controlling blast-furnace smelting are examined. A block diagram of a hardware-software complex developed for a blast furnace is presented along with scheme for integrating the furnace control system into the corporate control system at the factory. The system that has been developed creates a single informational-technological and control space that is closely linked to other information systems at the factory – especially the systems of the subdivisions whose performance has the greatest impact on the quality of the pig iron: the shop that prepares the sintering-machine charges, the sinter shop, the coke and coal chemicals plant, the BOF shop, the rail transport facility, the oxygen-plant/compressor station, and others. The main functional capabilities of the software are realized in the form of a model system that supports decision-making. This system is based on a group of mathematical models that solve various problems related to blast-furnace smelting. Users of the system can obtain missing information which is needed to make a decision by engaging in a dialog with the mathematical model. The results that have been obtained from using the informational-modeling system have improved response time and performance in the analysis, prediction, and planning of production situations, which in turn has improved decision-making by engineers and technicians when there are fl uctuations in the composition and quality of the iron-ore-bearing materials being smelted in the furnaces and changes in the market conditions.