Optimization of the ladle heating and drying technology on Azovstal Iron & Steel Works

The vertical stand for ladle heating at the Azovstal Iron & Steel Works has been examined. The purpose of preheating the steel ladles is to minimize the heat loss of the metal melt during melting and to increase the service life of the ladle lining. One of the main disadvantages of these stands is uncontrolled air suction. The sucked-in cold air mixes with the combustion products, reducing the temperature of the gas in the ladle space and increasing the amount of flue gases going out. This leads to a decrease in the efficiency of the ladle heating and, accordingly, to over-consumption of fuel (natural gas). To solve this problem a mathematical model has been made up. This model is based on the equation of the thermal balance of the ladle and describes the heat flows inside the ladle during the heating process. It makes it possible to analyze the influence of the cold air suction on the heating efficiency. The adaptation of the model was carried out basing on the data of the mode maps for this type of stands. Calculations made with the help of this model for a 350-ton steel-ladle at the Azovstal Iron & Steel Works showed that minimizing air suction will reduce fuel consumption for heating the steel ladle by 3 to 5%. To do this, it is necessary to regulate the underpressure in the ladle at the minimum necessary level, sufficient to completely remove the combustion products. It may be reached using automated control system