Numerical Simulation Of Thermal Deformation Behavior Of Copper Stave In The Blast Furnace

At present,the scale of the blast furnace(BF)becomes increasingly large and the production of the BF becomes more automatic and efficient.Nowadays,the cost of BF ironmaking accounts for half of the production cost in the iron and steel industry.As an important cooling equipment for the BF,safe and stable operation of the copper stave is of great significance to the life campaign and normal production of the BF.Only 41 months after its commission,No.4 BF of Meishan steel encountered three broken water pipe roots in the copper staves installed in the lower part of the shaft,affecting seriously the normal production.In this thesis,the copper stave in No.4 BF of Meishan steel was studied using the software of ANSYS Workbench.The temperature distribution as well as the corresponding stress-strain distribution of the copper stave under different conditions was simulated.At the same time,the shorter copper stave after the overhaul was also studied and its temperature and stress-strain distribution was compared with the one of the original longer copper stave.The main contents and results of the present thesis are summarized as follows.(1)According to the heat transfer law and the actual production conditions,the physical model of the copper stave was simplified.Based on relevant literature and experimental measurements,the thermal and mechanical property parameters for the calculation of temperature and stress-strain distribution were obtained.By comparing the simulated results with the practical measurements,the validity and accuracy of the model were confirmed.(2)The influence of temperature and velocity of cooling water,temperature and velocity of gas,thermal conductivity and thickness of slag crust,thermal conductivity and thickness of scale on temperature and stress-strain distribution of the copper stave were determined.The results showed that the temperature of the stave decreases to some extent by decreasing the temperature of cooling water,increasing the velocity of cooling water,reducing the temperature and velocity of gas,reducing the thermal conductivity of slag crust and scale,increasing the thickness of slag crust and scale.However,the influence on strain distribution is marginal.The influence of different installation conditions on the strain distribution of the stave was investigated and the installation condition was found to have great influence on the strain distribution.(3)Temperature and strain distribution were also calculated for the shorter cooper stave after overhaul.The general trend of the temperature distribution was found to be similar to that for the original longer copper stave.Nevertheless,the strain distribution differed significantly.(4)Based on the conditions of No.4 BF of Meishan steel,the reasons for the broken pipe root were discussed.Except for the limiting conditions,the maximum temperature for each calculation case was lower than the critical temperature of the copper stave.After the overhaul,the stave was shortened and the total deformation was found to be lower than before.The main reason for the broken pipe root is the structural defects of the stave,and the fluctuations in the fuel and operating conditions of the BF,as well as temperature variation and slag crust exfoliation and buildup can aggravate the damage.