Numerical modelling of steady state continuous crystallization processes using piecewise cubic spline functions

An efficient technique for computing the steady state crystal size distributions from continuous crystallization units is developed using piecewise cub The technique is simple, explicit and offers considerable computation savings over other available techniques. Solution techniques are developed for cr dependent growth and size dispersion. The numerical results are very satisfactory when compared with other techniques or exact analytical results

MODELLING OF THE BAYER ALUMINA PRECIPITATION SYSTEM.

A computer simulation of the precipitation area in a Bayer alumina plant has been developed. A modular design approach was adopted with individual modules for crystallizers, classifiers and mixers. These can be interconnected as desired thus allowing various precipitator configurations to be tested. Some preliminary results using the simulation have been obtained. Initial alumina concentration agglomeration rate and the effect of seeding and bypass strategy have been shown to have major effects on the precipitation process

GYPSUM CRYSTALLISATION IN WET PHOSPHORIC ACID MANUFACTURE: OPTIONS FOR PROCESS IMPROVEMENT.

A steady state simulation of the gypsum crystallization section of a hemihydrate/dihydrate wet phosphoric acid process has been developed. For given inlet process conditions, the model predicts the steady state process conditions, including the mean crystal size and size distribution. Using approximate kinetic relations, an analysis has been made for a simple flowsheet with a splitter giving solids recycle. This indicates that there is little scope for process improvements using the available operating variables. However by replacing the splitter with a clarifier or a classifier/clarifier combination, significant process improvements could be attainable