This article focuses on the synthesis and design of crystallization-based separation processes for systems involving solid solution in the presence of a solvent. A generic process consisting of two major parts: fractionation to obtain streams that are rich in a desired product and purification to get the final product with the desired purity has been developed. Solid-liquid equilibrium (SLE) phase diagrams and distribution diagrams are used in designing the flowsheet and determination of operating conditions. Various examples are presented to illustrate the use of this approach for different separation objectives and phase behaviors. (C) 2007 Elsevier Ltd. All rights reserved.