| At present, AOD with low production cost, high efficiency, easy operation, etc., and now it has become a mainstream smelting technology in the steel industry. But compared with the ordinary smelting furnace, AOD furnace’s life expectancy is much lower, as technical bottleneck of restricting the production line and boosting productivity. Therefore, this paper takes the AOD furnace as a specific object of study, with the help of kinetic theory of heat and chemical mechanism analysis methods, using of integrated control technology, through prototype development, and strive to achieve the integration of technology in the AOD furnace life research applications, thus greatly improving furnace life.This article introduced the domestic and foreign development present situation of the craft of protect furnace about AOD furnace and proposed this article’s research content, and then made a general analysis about improving AOD furnace life methods from the AOD furnace refractory lining, the slag basicity and composition control, pre-reaction wall slag furnace control technology and so on. And took the lining baking technology and endpoint control technology of smelting as the focuses of this paper, and carried out the following research work.Firstly, this paper focused on studies of the lining baking technology, making a detailed analysis about the AOD furnace lining the baking system and method of baking, using a new baking equipment of energy-saving effects, and making it automatic control, so that the device of baking can be more stable baking, to achieve better results, thereby increasing the life of the AOD furnace lining.Secondly, this paper focused on studies of the control of smelting technology, by adjusting the blown into the amount of oxygen and nitrogen to regulate the carbon content and temperature of the endpoint. Making it as soon as possible to achieve the required composition and temperature of ferroalloy smelting, and shorten the refining time, thereby indirectly increasing the life of the AOD furnace. In order to achieve dynamic control of the endpoint, the first to do is to establish an accurate model of the system parameters. Therefore, this paper based on thermodynamics theory and Metallurgical kinetics. After made the mechanism analysis, this paper based on the law of conservation of mass, non isothermal of smelting process, the law of conservation of energy and grey theory established the mathematical model of the relationship between carbon content and oxygen supply rate, the mathematical model of the relationship between carbon content and nitrogen supply rate, the mathematical model of the relationship between temperature and oxygen supply rate and the mathematical model of the relationship between temperature and nitrogen supply rate. And then calibrated to some parameters of the mode based on the collected experimental data of Jilin Liaoyang Ferroalloy Factory, to improve model accuracy.Finally, the paper based on the established model that Above-mentioned, tried using conventional control methods and inferential control to achieve end-point control. With oxygen as the set value, with nitrogen as unpredictable disturbances, with temperature of molten iron as second output to indirect control the main output that carbon content of molten iron. And the model of the relationship between input and output were created and described by the Simulink in the Matlab7.0. Through a comparative analysis of simulation results obtained:under the condition of the model are accurately, in ferroalloy smelting endpoint temperature and carbon content control, inferential control is superior to conventional control algorithms. Moreover, this paper based on DCS established the AOD furnace ferroalloy smelting electrical automatic control system. By first-level system to handle complex data operations, and centralized operation monitoring; by the second-level system to achieve the control of the tilting furnace subsystems, supplying gas subsystems, feeding subsystems and other subsystems. |
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