Solid-liquid mass transfer in relation to diffusion controlled corrosion at the outer surface of helical coils immersed in agitated vessels

摘要

The diffusion controlled dissolution of copper in acidified dichromate solution technique was used to study solid-liquid mass transfer at the outer surface of helical coils immersed in unbaffled agitated vessel. Variables studied were impeller rotation speed, impeller geometry (four blade 90 turbine and 45 pitched blade turbine), distance between coil rings (coil pitch) and physical properties of the solution. The data were correlated in the form of dimensionless equations, for four blade 90 turbine impeller, the data fit the equation: Sh = 0.023 Sc~(0.33) Re~(0.59) (d_c/S)~(0.49) while for four blade 45 pitched turbine impeller, the data were correlated by the equation: Sh = 0.13 Sc~(0.33) Re~(0.51) The above equations were obtained for unbaffled vertical cylindrical vessel of flat bottom in the range: 4705 < Re < 52,750, 1104