Last update:
10/28/2004
Numerical Modeling of Membrane Desalination
Comprehensive numerical models are under development to predict the axial development of concentration polarization in complex membrane geometries for multi-ion systems and accounting for the formation of surface mineral scale. In the present approach the coupled hydrodynamics and mass transfer equations are solved simultaneously accounting for the dependence of all physicochemical and thermodynamics properties on concentration, pH and temperature.
Our goal in this work is to develop models that can be used to determine optimal operating conditions for membrane desalination under realistic conditions and complex flow geometries.
A future goal is to couple such models with on-line sensors (i.e., various measures of plant performance data and auxiliary foulant sensors) to provide real-time assessment of membrane fouling,
Results of a finite element model of axial development of concentration polarization in a rectangular RO membrane channel.
Hydrodynamics
CFD display of recirculation regions at the exit region (Figure A) from a plate-and-frame RO channel (Figure B). The recirculating region is formed due to the use of an o-ring that seals the membrane channel. The existence of recirculation can result in the accumulation of colloidal foulants and mineral salt precipitates at the edges of the channel.
Figure A.
Figure B. Plate-and-Frame Membrane RO Channel
Illustration of model results for axial development of concentration polarization in a rectangular RO channel in the presence of gypsum scale formation.
