Monolithic stoppers play a very important role in continuous casting（ short for CC）. Sometimes,the stopper slag line is seriously eroded and broken,CC has to pause. The research shows that there are three main reaso...Monolithic stoppers play a very important role in continuous casting（ short for CC）. Sometimes,the stopper slag line is seriously eroded and broken,CC has to pause. The research shows that there are three main reasons which bring severe erosion of monolithic stopper slag line. Firstly,much Fe_2O_3 and MnO in slag react with carbon（ C） in the stopper,C is gradually eroded and erosion resistance of the stopper greatly weakens. Secondly,F increase in tundish covering flux will quicken erosion of the stopper slag line. Thirdly, High LOI of tundish covering flux also makes erosion of the stopper slag line speed up. On one hand,CaCO_3 in tundish covering flux decomposes and brings CO_2; on the other hand,minerals with water in tundish covering flux decompose at high temperatures and bring water vapor.Then CO_2 and water vapor react with C in the stopper,C is gradually eroded,aggravating the erosion.展开更多
The control design, based on self-adaptive PID with genetic algorithms(GA) tuning on-line was investigated, for the temperature control of industrial microwave drying rotary device with the multi-layer(IMDRDWM) and wi...The control design, based on self-adaptive PID with genetic algorithms(GA) tuning on-line was investigated, for the temperature control of industrial microwave drying rotary device with the multi-layer(IMDRDWM) and with multivariable nonlinear interaction of microwave and materials. The conventional PID control strategy incorporated with optimization GA was put forward to maintain the optimum drying temperature in order to keep the moisture content below 1%, whose adaptation ability included the cost function of optimization GA according to the output change. Simulations on five different industrial process models and practical temperature process control system for selenium-enriched slag drying intensively by using IMDRDWM were carried out systematically, indicating the reliability and effectiveness of control design. The parameters of proposed control design are all on-line implemented without iterative predictive calculations, and the closed-loop system stability is guaranteed, which makes the developed scheme simpler in its synthesis and application, providing the practical guidelines for the control implementation and the parameter design.展开更多
Physical properties of molten slag such as viscosity, density and surface tension have a significant influence on the slag splashing process in an oxygen steelmaking converter. Particularly, viscosity determines the s...Physical properties of molten slag such as viscosity, density and surface tension have a significant influence on the slag splashing process in an oxygen steelmaking converter. Particularly, viscosity determines the shear forces that rule droplets formation. Besides, stirring of the molten slag bath strongly depends on this property. In this work, the influence of viscosity on the efficiency of slag splashing is explored by means of transient Computational Fluid Dynamics simulations. Several values of viscosity are employed in the computer experiments. In order to quantify the splashing efficiency as function of slag viscosity, an average slag fraction on the converter walls is defined and calculated. CFD results are compared with those of an empirical expression, and at least qualitative agreement is found.展开更多
The influence of three different blowing conditions on the slag splashing process in a basic oxygen furnace for steelmaking is analyzed here using two-dimensional transient Computational Fluid Dynamics simulations. Fo...The influence of three different blowing conditions on the slag splashing process in a basic oxygen furnace for steelmaking is analyzed here using two-dimensional transient Computational Fluid Dynamics simulations. Four blowing conditions are considered in the computer runs: top blowing, combined blowing using just a bottom centered nozzle, combined blowing using two bottom lateral nozzles, and full combined blowing using the three top and the three bottom nozzles. Computer simulations show that full combined blowing provides greater slag splashing than conventional top blowing.展开更多
文摘Monolithic stoppers play a very important role in continuous casting（ short for CC）. Sometimes,the stopper slag line is seriously eroded and broken,CC has to pause. The research shows that there are three main reasons which bring severe erosion of monolithic stopper slag line. Firstly,much Fe_2O_3 and MnO in slag react with carbon（ C） in the stopper,C is gradually eroded and erosion resistance of the stopper greatly weakens. Secondly,F increase in tundish covering flux will quicken erosion of the stopper slag line. Thirdly, High LOI of tundish covering flux also makes erosion of the stopper slag line speed up. On one hand,CaCO_3 in tundish covering flux decomposes and brings CO_2; on the other hand,minerals with water in tundish covering flux decompose at high temperatures and bring water vapor.Then CO_2 and water vapor react with C in the stopper,C is gradually eroded,aggravating the erosion.
基金Project(51090385) supported by the Major Program of National Natural Science Foundation of ChinaProject(2011IB001) supported by Yunnan Provincial Science and Technology Program,China+1 种基金Project(2012DFA70570) supported by the International Science & Technology Cooperation Program of ChinaProject(2011IA004) supported by the Yunnan Provincial International Cooperative Program,China
文摘The control design, based on self-adaptive PID with genetic algorithms(GA) tuning on-line was investigated, for the temperature control of industrial microwave drying rotary device with the multi-layer(IMDRDWM) and with multivariable nonlinear interaction of microwave and materials. The conventional PID control strategy incorporated with optimization GA was put forward to maintain the optimum drying temperature in order to keep the moisture content below 1%, whose adaptation ability included the cost function of optimization GA according to the output change. Simulations on five different industrial process models and practical temperature process control system for selenium-enriched slag drying intensively by using IMDRDWM were carried out systematically, indicating the reliability and effectiveness of control design. The parameters of proposed control design are all on-line implemented without iterative predictive calculations, and the closed-loop system stability is guaranteed, which makes the developed scheme simpler in its synthesis and application, providing the practical guidelines for the control implementation and the parameter design.
文摘Physical properties of molten slag such as viscosity, density and surface tension have a significant influence on the slag splashing process in an oxygen steelmaking converter. Particularly, viscosity determines the shear forces that rule droplets formation. Besides, stirring of the molten slag bath strongly depends on this property. In this work, the influence of viscosity on the efficiency of slag splashing is explored by means of transient Computational Fluid Dynamics simulations. Several values of viscosity are employed in the computer experiments. In order to quantify the splashing efficiency as function of slag viscosity, an average slag fraction on the converter walls is defined and calculated. CFD results are compared with those of an empirical expression, and at least qualitative agreement is found.
文摘The influence of three different blowing conditions on the slag splashing process in a basic oxygen furnace for steelmaking is analyzed here using two-dimensional transient Computational Fluid Dynamics simulations. Four blowing conditions are considered in the computer runs: top blowing, combined blowing using just a bottom centered nozzle, combined blowing using two bottom lateral nozzles, and full combined blowing using the three top and the three bottom nozzles. Computer simulations show that full combined blowing provides greater slag splashing than conventional top blowing.
