Study On Heat Transfer Law Of Steel Slag Wind Quenching Process And Improvement Of Process Line

Steel slag is a by-product discharged in steelmaking process,which contains a variety of metal resources and abundant high-quality waste heat resources for recycling.Steel slag accounts for about 8% ? 15% of the total crude steel output and improper treatment of steel slag will lead to land occupation,environmental pollution and other problems.Different steel slag treatment methods will directly affect the recycling efficiency of metal resources and heat resources in steel slag.With the development of steel-making industry,a variety of processing technologies have emerged,such as cold abandoning method,wind quenching method,water quenching method,hot splashing method,heat stifling method,roller method and plate splashing method.Compared with other processing techniques,wind quenching method can realize efficient granulation of high-temperature liquid steel slag,effectively control the particle size of slag particles,and avoid secondary crushing of slag particles.At the same time,heating air is used as the medium to effectively recover the waste heat resources of steel slag and improve the energy utilization rate.Steel slag is affected by wind speed,wind pressure and other factors during wind quenching,which involves heat transfer,impact of air and fluid,phase transformation of steel slag and other problems.In this dissertation,for different stages of steel slag wind quenching production line,the theoretical analysis of liquid steel slag under the influence of different factors was carried out respectively,and the numerical simulation of key influencing factors was carried out to explore and verify the rationality of the existing granulation chamber process layout and production parameters.Combined with the results of theoretical analysis and numerical simulation,the existing production lines were optimized and improved.The specific research work of this dissertation is as follows:1.According to the actual production process of steel slag air quenching process,mathematical modeling was carried out,and each element of the air quenching process was compared and analyzed.The influences of nozzle diameter,high speed jet pressure,surface tension,steel slag viscosity and steel slag superheat on the granulation effect were investigated respectively.Combined with the physical parameters of steel slag samples,a hydrodynamic calculation model was established for the actual wind quenching process of steel slag.The finite element analysis software Fluent was used to solve the granulation process of liquid steel slag and the solidification process of steel slag particles respectively.2.Based on Fluent software for steel slag quenching jet flow field in the process of wind,liquid steel slag by high pressure high speed jet impact crushing granulation process,graining of steel slag particles of heat exchange cooling solidification process of the numerical results,the following results were explored respectively: The influence of nozzle diameter and jet velocity on the distribution of jet flow field,the variation of steel slag granulation process,the influence of different wind speeds and different particle sizes on the heat transfer solidification process of slag particles.3.Combined with theoretical analysis of steel slag quenching process of the wind and the numerical simulation results of different wind quenching stage,this study optimized the existing steel slag quenching process line wind by replacing the thermal process of hoisting slag pot with a new type of steel slag transport cars and rotating commutator platform whose mechanical properties were checked.In this case,the production efficiency of the new type of steel slag wind quenching process line is improved by reducing the time between slag discharge and wind quenching,and the economic benefit of the new type of steel slag wind quenching process line is estimated.