Energy Analysis And Optimization Of Rotary Hearth Furnace System Processing Metallurgical Iron-containing Solid Waste

Iron and steel enterprises produce a large amount of iron-containing solid waste in the production process.If it is not treated,it causes environmental pollution and waste of resources.The direct reduction process of rotary hearth furnace is one of the effective methods for the treatment of iron-containing solid waste generated by iron and steel enterprises.It has good adaptability to iron-containing metallurgical dust and a high dezincification rate.Energy analysis and optimization of the rotary hearth furnace system can effectively grasp the energy flow and material flow of the rotary hearth furnace system,and optimize the system energy consumption,which is of great significance to the overall system’s energy saving and cost reduction.This study developed an energy analysis and optimization software for the rotary hearth furnace system treating metallurgical iron-containing solid waste based on methods of material balance,energy balance,exengy balance,and mathematical planning modeling,which can quickly calculate the energy distribution of the entire system.And get the optimal operating parameters.In this paper,the energy analysis of the rotary hearth furnace system is performed.The material balance,energy balance,and thorium balance of each process are calculated.The evaluation indexes such as thermal efficiency,thorium efficiency,and loss coefficient of each process are obtained.The reasons for energy loss are analyzed and the corresponding suggestions are proposed.Energy saving measures.At the same time,the thermal efficiency of the rotary hearth furnace system is 51.79%and the exengy efficiency is 25.42%.The heat loss weight and radon loss weight of each process of the rotary hearth furnace system are compared horizontally.The result shows that the heat loss and exengy loss of the reduction process have the largest weight,which is the focus of energy saving in the entire rotary hearth system.At the same time,Optimize the cost,energy consumption and carbon dioxide emissions per ton of direct reduced iron(DRI)produced by the rotary hearth furnace system respectively.The result shows that the production cost of the optimized system is reduced by 162.85yuan/tDRI and energy consumption is reduced by 83.47kgce/t-DRI,CO2 emissions decreased by 348.61kg/t-DRI.Multi-objective optimization of the rotary hearth furnace system,and the use of structural similarity approach to select the optimization result closest to the ideal solution,at this time the production cost is reduced 161.23yuan/t-DRI.Energy consumption is reduced by 83.16kgce/t-DRI.CO2 emissions are reduced by 195.65kg/t-DRI.The influence of operating parameters in the rotary hearth furnace system on the system is analyzed,and the results show that the cost,energy consumption and CO2 emissions of the system decrease as the grade of raw materials increases.As the preheating temperature of air and mixed gas in the rotary hearth furnace increases,the system’s cost,energy consumption,and CO2 emissions first decrease and then increase,and the optimal preheating temperature ranges for air and mixed gas are obtained,which are 450～550K and 360～420K respectively.The increase of the CO post combustion rate is beneficial to reduce the system cost,energy consumption and CO2 emissions.Increasing the product metallization rate increases the system cost,energy consumption and CO2 emissions.