In the present work mathematical models based on set of nonlinear equations have been developed for the synthesis of multiple effect evaporator (MEE) systems. A number of configurations and complexities of real MEE system such as condensate, feed and product flashing, vapor bleeding, steam splitting, variable physical properties and boiling point rise are accounted to develop of different models. Along with these a model for predicting fouling resistance is also developed using the experimental data. Developed models for MEE system are compared based on product concentration and steam economy to select the optimum model. The results of the selected model are validated with published model and industrial data. The operability analysis with pressure constraints is carried out for the selected model and for the modified MEE system capital investment, operating cost, profit as well as payback period is computed. (C) 2012 Elsevier B.V. All rights reserved.