Numerical simulationon centrifugal granulation characteristics of slag optimized by gas quenching winds
The liquid slag dry granulation and waste heat recovery technology solves the problem of waste heat loss and environmental pollution caused by the existing water quenching process of liquid slag in metallurgical industry,which plays an important role in the implementation of energy saving and emission reduction strategy.In order to improve the resource utilization of slag pellets and reduce the equipment investment,the addition of auxiliary gas quenching wind at the edge of the pelletizer is proposed to enhance the palletizations effect and improve the waste heat recovery efficiency.However,the mechanism of the effect of gas quenching wind on centrifugal granulation and the influence pattern are still unclear in the current study.A three-dimensional granulation model with gas quenching wind was established using the SST k-ω turbulence model.And the effects of gas quenching wind on the granulation effect,the flight velocity of waste particles and the cooling effect of rotor cup were investigated by using the VOF method.The changing rule of the horizontal flight speed of liquid droplets under different gas quenching wind conditions was investigated to provide reference basis for optimizing the flight trajectory of liquid droplets and the spatial design of granulation silo.Findings indicated that while increasing air volume shifted particle size distribution to larger ranges,it benefited the slag particles'sphericity.The gas quenching wind effectively induced particle fragmentation within the air flow range of 4～6 m3/h,with enhanced cooling effects when air flow surpassed 2 m3/h.When selecting the air flow,the air flow of 1 m3/h can be selected when considering the granulation effect and flight speed only,and the flow of 2 m3/h was the best when considering the cooling effect comprehensively.Using a ring slit for air venting resulted in the smallest average diameter of slag particles,lower wall temperatures near the rotating cup,moderate flight speed,and superior sphericity compared to a state without gas quenching wind.
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