Ladle Heating Procedure and Its Influence on the MgO–C-Oxidation

Abstract

The efficiency of ladle heating can be substantially improved by preheating the combustion air using waste gas, oxygen enriching of the air, or changing the air ratio. These actions lead to an increase of the combustion temperature and a decrease of the waste gas volume rate. Hence the knowledge of the flow conditions in the ladle is of decisive importance for further reduction of the waste gas flow rate. The commercial CFD-code (Computational Fluid Dynamic) Fluent 6.3 was used to model the flow conditions in the ladle. The commercial thermodynamic software FactSage 5.3 was used to model the chemical processes such as combustion temperature, chemical composition of the waste gas, and in special the NO _x production during natural gas combustion. For the calculation of the temperature distribution in the ladle lining, the flow model was coupled with a FDM (Finite Difference Method)-based thermal ladle model. The change of the combustion temperature and waste gas composition affects significantly the surface of the MgO–C-refractory lining. The oxidation of MgO–C containing 12 wt% carbon was investigated at various temperatures (1500 to 1600^°C) in air atmosphere with and without air flow.

Keywords:

• Air ration
• CFD-model
• Combustion air heating
• Flame temperature
• Flow field
• Heating efficiency
• Improvement of heating efficiency
• Ladle heating procedure
• MgO–C-refractory
• MgO-protective layer
• Oxydation
• Oxygen enriched air
• Steelmaking ladle
• Temperature field
• Thermal model

Notes

CCS = cold compression strength; a = in pressing direction; b = vertical to pressing direction; OP = open porosity.