A methodology for multi-level conceptual design and analysis of crystallization-based separation processes involving electrolyte systems is presented. The methodology consists of three main parts: thermodynamic part (level 1). flowsheet design/analysis part (level 2) and flowsheet validation (simulation) part (level 3). In this paper, the integration of the thermodynamic and design/analysis parts is presented. This integration allows the analysis of the thermodynamic behavior of a given system together with design/analysis of flowsheet alternatives in the same calculation environment. The integrated system is highlighted through four practical examples where features of the algorithm related to creation of property model package and its usage in flowsheet design/analysis are highlighted.