Application of CFD modelling to precipitation systems

A CFD package was employed to simulate the steady state precipitation of barium sulphate in jet mixing devices. Both 2D and 3D descriptions were employed, Solutions of the Navier-Stokes equations along with the standard two equation k-epsilon turbulence model provide the velocity and energy fields while generation and development of the solid crystal phase were described by the moment equations of the population balance. Spatial distributions of species concentrations, supersaturation, total crystal number and magma density were calculated and the average size and coefficient of variation of the crystal product determined. Visualization of these distributions enables a rapid assessment of the effect of the actual flow pattern within a particular jet precipitator. The influence of the positions and orientation of the two inlet streams, as well as the length of the mixer on the mixing and the precipitation were investigated.