This study presents the steady-state simulation and optimization of a six-effect evaporator and the provision of its relevant software package. in this investigation, the modeling equations of each of the existing building blocks are written in a steady-state conditions. These equations have been used for simulation and process optimization of the entire vaporizing unit while exercising the simplifying assumptions. The effect of different parameters on consumed steam produced distilled water and GOR is presented. The feed mass flow rate, condenser pressure and operating time are optimized for this system. The simulation results are good agreement with design data. (c) 2008 Elsevier B.V. All rights reserved.