Modelling the film fragmentation of industrial-scale centrifugal granulation of high-temperature molten slag

Abstract

Centrifugal-granulation-assisted thermal energy recovery (CGATER) is one of the most promising routes to enable waste heat harvest from molten slags. However, it remains a grand scientific and technological challenge to produce fine particles from the bulk high-temperature molten slag, especially at large slag throughput. In this work, we established an improved model to simulate the centrifugal granulation at the large flowrate comparable to the laboratory- pilot-scale trials. For the first time, film fragmentation has been successfully reproduced by modelling. On this basis, we elucidated the intricate film fragmentation by quantifying the off-atomizer film characteristics at various operational conditions, with a strong focus on the metrics of the off-atomizer slag film. The present study provides an important and valuable CFD model to approach the underlying physics of film fragmentation. Most importantly, it opens up new possibilities for predicting slag droplet formation at experimentally unavailable operational conditions.