Mariiash Y. Model-Predictive Automatic Control of the Blowing Mode of an Oxygen Converter With Energy-Efficient heat Absorption

The purpose of the study is to reduce the cost of oxygen-converter steel, which is a consequence of the increase in the share of scrap metal due to the increase in the degree of post-burning of CO to CO2 in the converter cavity, by optimal control of the parameters of the duty mode using model predictive control. In the dissertation, the mathematical model of the blowing mode of basic oxygen furnace process was improved, taking into account the influence of the intensity of blasting on the process of decarburization of the bath, which made it possible to increase the accuracy and quality of blasting control in the conditions of changes in the oxygen consumption during purging. For the first time, an optimal control system for the parameters of blowing mode during basic oxygen furnace process was synthesized based on the principle of feedback with model-predictive control using a linear-quadratic functional, which allowed simultaneous control of the blowing intensity and the position of the lance, as well as to improve the quality of control and energy saving during melting, due to the increase in the degree of post-burning of CO to CO2, which is a consequence of the increase in the proportion of scrap metal. Further development was achieved by the use of closed control systems for the degree of post-burning of CO to CO2, through the synthesis of a model predictive controller taking into account the technological saturation of the speed of movement of regulatory bodies, which allowed to improve the quality of process control in the presence of saturation. The existing automatic control systems do not fully satisfy the requirements for the quality of the system's operation during software control of the parameters of the blowing mode and stabilization of disturbances. A comparative study of the operation of the model predictive controller and the combined regulation system with PID controller showed that the obtained transient processes of the system of automatic control of the blowing mode of the basic oxygen furnace from the model predictive controller provided ISE for the circuit of oxygen consumption - 5577 and the content of CO2 - 43; the maximum dynamic deviation of the CO2 content in converted gases was 0.95%. The use of a model predictive control made it possible to improve the quality of control for the oxygen consumption by 1.63 times; the maximum dynamic deviation of CO2 content was reduced by 16.5% in comparison with the combined control system with PID controller.