mass transfer in multiphase systems - Greenleaf University

MASS TRANSFER IN MULTIPHASE SYSTEMS: VOLATILE ORGANIC COMPOUND
REMOVAL IN THREE-PHASE SYSTEMS
primarily power/volume correlations used for liquids. These are limited and have some
correlations for solid-liquid mass transfer coefficients for mixed systems and were used in the
analysis for the System 2 design as well (Oldshue 1983), (Harnby 1992).
Other potentially applicable literature that had various applications includes (Zhao 2003),
(Muroyama 2001), (Levenspiel 1972), (Fishwick 2003). While some of the work was similar,
there were not any direct analogs. The derivation for 3-phase mass transfer is unique and has
been published in a government-owned document (Ashworth 2004). Relationships between
equilibrium constants (Henry’s constants and solid-liquid partitioning) and transient mass
transfer are needed to understand and predict system behavior. These were not found in the
literature search and needed to be derived.
The primary process in this work dealt with transfer of VOCs from a slurry phase into
air-stripping air. The literature search focused on finding correlations for a mass transfer
coefficient as a function of the design parameters, e.g., the degree of agitation, gas rate, particle
size and others. It was also desired to find a theory for using the Henry’s Law constant and the
solid-liquid partition coefficient to predict the batch rates for different VOCs. The available
literature covered several types of topics including: 1) derivations from molecular diffusion as in
Ficks’ Laws (Thibodeaux 1979) 2) air stripping studies involving non-batch, continuous systems,
3) air stripping studies involving single-phase systems, and 4) other topics that while useful, did
not provide an answer especially to the non-homogeneous, multiple-phase nature of the unique
wastes prevalent at the facility.
8