Синтез модельно-прогнозуючого регулятора режиму дуття киснево-конвертерного процесу

Abstract

The purpose of the research was to find a solution for a decrease in the cost price of the basic oxygen furnace steel. It is conditioned by an increase in the scrap metal portion due to an increase in the СО to CO2 afterburn degree in the basic oxygen furnace cavity according to the optimal model predictive control of the parameters of the blowing mode. The optimal parameter control system was synthesized for the blowing mode of the oxygen-converter melting on the basis of the feedback based on the model-predictive control using the linear-quadratic functional and it enabled a simultaneous control of the blowing intensity and the lance position  when programmatically changing the task for the oxygen consumption and CO2 content improving also the control quality and energy saving during the melting process due to an increased afterburn degree during the CO to CO2 conversion that is a consequence of an increased portion of the scrap metal. Closed CO to CO2 afterburn degree control systems were improved by the synthesis of the model-predictive controller taking into consideration process limitations imposed on the shifting rate of controlling mechanisms, improving thus the process control quality in the case of the limitations. The suggested solution enables certain process control quality improvement under the conditions of process limitations. A comparative investigation of the operation of the model – predictive controller and combined control system with PID–controllers showed that the obtained transition processes of the automatic control of the blowing mode for the basic oxygen furnace melting using the automatic model-predictive controller  provided ISE values for the oxygen consumption loop equal to 5577 and the CO2 content equal to 43 in basic oxygen furnace gases with a maximum dynamic deviation of the CO2 content in converter gases equal to 0.95 %. The use of the model-predictive controller allowed us to improve the control quality for the oxygen consumption loop by a factor of 1.63 CO2 and by a factor of 32.5 for the CO2 content control loop in converter gases. A maximum dynamic deviation of the CO2 content in converter gases was reduced by 16.55 % in comparison to that in the combined control system equipped with PID-controllers.