Comparative study of the fluid dynamics of bottom spray fluid bed coaters
AUTOR(ES)
Chan, L. W.
FONTE
Springer-Verlag
RESUMO
Fluid dynamics of pellets processed in bottom spray traditional Wurster coating and swirl accelerated air (precision) coating were compared with the intent to understand and facilitate improvements in the coating processes. Fluid dynamics was described by pellet mass flow rate (MFR) obtained using a pellet collection system and images captured using high speed photography. Pellet flow within the partition column was found to be denser and slower in Wurster coating than in precision coating, suggesting a higher tendency of agglomeration during the coating process. The influence of partition gap and load on the MFR indicated that the mechanism of transport of pellets into the coating zone in precision coating depended on a strong suction, whereas in Wurster coating, pellets were transported by a combination of peripheral fluidization, gravity, and weak suction pressure. In precision coating, MFR was found to increase uniformly with air flow rate and atomizing pressure, whereas MFR in Wurster coating did not correlate as well with air flow rate and atomizing pressure. This demonstration showed that transport in precision coating was air dominated. In conclusion, fluid dynamics in precision coating was found to be air dominated and dependent on pressure differential, thus it is more responsive to changes in operational variables than Wurster coating.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=2750287Documentos Relacionados
- A study of the fluid dynamics of the spouted bed using CFD
- Oxidation of zinc sulphide concentrate in a fluidised bed reactor - Part 1: Characterization of the fluid dynamics of the particle bed
- Experimental and numerical study of spouted bed fluif dynamics
- Fluidodinamica, secagem e recobrimento em leito pulso-fluidizado
- Estudo comparativo da produção de extrato seco de ´Bauhinia forficata` Link pelos processos ´spray-dryer` e leito de jorro