| China’s iron and steel industry is based on the process of coking-sintering-blast furnace-converter,in which the blast furnace ironmaking process is responsible for 60% of the total process energy consumption,90% of the total pollutant emissions,making blast furnace ironmaking is facing huge environmental pressure.As a key part of blast furnace ironmaking charge structure,block ore can be made without adding fuel,which has the advantages of low cost,low energy consumption and less pollution emission.Therefore,a high proportion of block ore into the furnace is an effective measure to realize blast furnace energy conservation and emission reduction.Because the block ore contains more crystal water and carbonate minerals,so the water content is higher,the surface is easy to adhere to more powder,not easy to sieve,affecting the normal operation of the blast furnace.In order to ensure the stable operation of blast furnace,the cylinder dryer with high drying efficiency and widely used was used to dry lump ore to reduce the moisture content.In view of the current use of cylinder dryer is only limited to rely on practical experience to adjust the operational indicators,lack of accuracy,this paper takes cylinder dryer as the research object,combines experiment and simulation analysis,studies how to improve the drying effect of block ore in cylinder dryer,the main research work is as follows:(1)Analyze the working principle of cylinder dryer and study the movement process of block ore.The movement process o f block ore is divided into ascending and descending processes.Firstly,the Angle of re pose and the maximum unloading Angle are calculated according to the parameters of block ore.Secondly,the falling height and time of the block ore are calculated acco rding to the unloading Angle of the block ore and the parameters of the hoisting plate.Thirdly,the horizontal advance distance of block ore is obtained by analyzing the horizontal movement law of block ore.Finally,the total residence time is calculated according to the motion state of block ore,so as to establish the mathematical model of residence time of block ore in cylinder dryer.(2)Based on discrete element method,the motion law of block ore in cylinder dryer is studied.In this paper,the cyli nder dryer model is established,the movement process of block ore in the cylinder dryer is modeled and simulated,the wear of the cylinder dryer is analyzed,and the residence time and distribution of block ore particles in the cylinder dryer are analyzed,and the cylinder inclination,cylinder speed and particle size difference are selected as the main operating parameters.The influence of the above parameters on the residence time and distribution of block ore is studied by discrete element simulation.(3)The drying process of block ore in cylinder dryer is simulated,and the results are verified experimentally.Based on the theory of heat and mass transfer,mathematical models were established for parameters such as moisture content,flue gas temperature,bulk particle temperature and heat loss of cylinder dryer.According to the mathematical model,MATLAB software was used to simulate and calculate the changes of parameters in the process of block ore drying under standard conditions,and the reliability of the drying model was verified by experiments.(4)Based on the drying model,the operating parameters affecting the drying process were analyzed and optimized.Taking inlet flue gas temperature,inlet flue gas velocity and cylinder dryer speed as working parameters,the influence rule of above parameters on block ore drying process is obtained through simulation analysis,and the simulation results are fitted into a curve to judge whether it meets the actual engineering requirements.On this basis,ai ming at the moisture content of the lump ore at the outlet and the heat loss of the cylinder dryer,the drying process was optimized to obtain the optimal parameter combination under the joint action of inlet flue gas temperature,inlet flue gas velocity a nd cylinder dryer speed. |
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