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Mass transfer between solid and liquid in vessels agitated by bubble plume
Author(s) -
Mazumdar Dipak,
Kajani Srikanth K.,
Ghosh Ahindra
Publication year - 1990
Publication title -
steel research
Language(s) - English
Resource type - Journals
eISSN - 1869-344X
pISSN - 0177-4832
DOI - 10.1002/srin.199000359
Subject(s) - dimensionless quantity , mass transfer , turbulence , chemistry , bubble , reynolds number , thermodynamics , intensity (physics) , mechanics , plume , mass transfer coefficient , turbulence kinetic energy , heat transfer , dissolution , physics , chromatography , optics
Mass transfer from solid benzoic acid cylinders to a gas‐stirred aqueous bath has been investigated both theoretically and experimentally. Two typical gas injection configurations, the conventional central injection and the C.A.S. ( C omposition A djustment by S ealed Argon Bubbling) were employed and the rates of dissolution of the acid compacts at various locations in the bath were measured at different gas‐flow rates. These demonstrated that the mass‐transfer rates are the highest in the two‐phase region, while elsewhere in the bath, these were found to be practically identical. Furthermore, mass‐transfer rates at the corresponding locations were found to be relatively greater for the conventional central injection than those for the C.A.S. configuration. Distribution of velocity and turbulence intensity in the vessel were computed theoretically using a previously reported calculation procedure. Based on these, values of various relevant dimensionless numbers were estimated so as to assess the adequacy and effectiveness of heat and mass‐transfer correlations reported in the literature. These, however, did not fit with the present experimental observations. For this reason, a new correlation has, therefore, been proposed and it is shown that the experimental data can be described reasonably well by the equation Sh = 0.73 ( Re loc,r ) 0.57 ( T i ) 0.32 ( Sc ) 0.3 . This correlation also embodies more plausible definitions of Reynolds number ( Re loc,r ) and the turbulence intensity ( Ti ) in contrast to those reported in literature, since it has been derived using the local resultant mean velocity and the local fluctuating velocity in the fluid.