Numerical Simulation On Billet Heating And Iron Scale Loss In Disc Reheating Furnace

With the increasing implementation of China’s energy conservation and emission reduction policies and the price of iron ore is also rising.All enterprises,especially iron and steel enterprises,are forced to carry out industrial upgrading in order to achieve green production,reduce pollutant emissions and improve production efficiency.As an important link for disc heating furnace in iron and steel plant,the billet heating process must be further improved,which is of great significance to the improvement of technical equipment in the whole iron and steel production process.Based on the thermal theory for heating furnace,a 40 t/h disc heating furnace is designed.The structural size,heating conditions and burner selection of the disc heating furnace are determined.Then,taking the 40 t/h disc heating furnace as the research object,the mathematical model of billet movement in the disc heating furnace is built based on dynamical grid technology,and the feasibility of the model is verified.The numerical simulation of the billet heating process in the disk heating furnace under the design case shows that in the process of billet heating,the heating rate of the first heating section rises rapidly,the heating rate of the second heating section decreases,and the temperature of the soaking section tends to be stable.There is corner effect during billet heating.Oxygen is fully burned in the furnace,and the distribution of carbon dioxide,steam and carbon monoxide produced by the chemical reaction is different.Because the heating sections have large fuel flow,large amount of carbon dioxide and steam generates,and inhibits the generation of carbon monoxide.The dynamic heating characteristics of billet movement in disk heating furnace under different operating parameters such as oxygen concentration,heating time,air preheating temperature and fuel preheating temperature are explored.The results show that under higher oxygen concentration,the chamber temperature increases and the billet exit temperature increases.Prolonging the heating time does not have much effect on the chamber temperature.The longer the heating time,the better the uniformity of billet temperature.As increasing the air/fuel preheating temperature,both the chamber temperature and billet discharge temperature increase.According to the orthogonal table,the operation parameters such as heating time,air preheating temperature,fuel preheating temperature and oxygen concentration are optimized and analyzed by the grey correlation method.The results show that the importance order of the factors affecting the billet discharge temperature difference are heating time（X₂）,fuel preheating temperature（X₁）,oxygen concentration（X₄）and air preheating temperature（X₃）,which are predicted by multiple nonlinear regression,The relationship between billet discharge temperature and operating parameters is obtained:（?）The iron scale loss model of billet movement in disk heating furnace was established,and the iron scale loss of billet dynamical heating in disk heating furnace was simulated under different billet charging temperature and oxygen concentration.The results show that the billet charging temperature has little effect on the iron scale loss.The iron scale loss of billet increases with the increase of oxygen concentration.