Polydispersity effects on axial dispersion in two-phase separation processes
- Air Products and Chemicals, Inc., Allentown, PA (USA)
The existence of a distribution of rise velocities due to a non-uniform size distribution frequently leads to inefficient contacting in dispersed two-phased separation processes. A generalized Taylor dispersion analysis has been employed to determine the exact transient behavior of the appropriately defined dispersion coefficients and to explore their dependence on the local transport rates, including the diffusion rate within the drops and the interphase mass transfer rate from the drop surface to the bulk fluid. For a pulsed injection of tracer into the dispersed phase and for times short relative to the overall mass transfer time, the dispersive behavior is close to the purely convective limit appropriate when mass transfer is not possible. The dispersed phase dispersion coefficient overshoots its asymptotic value by nearly a factor of two at intermediate times, and a constant long-time value is approached from above thereafter. These results demonstrate the fundamental role that interphase mass transfer plays in the dispersion process.
- OSTI ID:
- 5359239
- Report Number(s):
- CONF-881143-
- Resource Relation:
- Conference: American Institute of Chemical Engineers annual meeting, Washington, DC (USA), 27 Nov - 2 Dec 1988; Other Information: Technical Paper 28I
- Country of Publication:
- United States
- Language:
- English
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