This paper documents the implementation of the desalination technology of multi-stage flash distillation (MSF) into the commercial process simulation tool IPSEpro. This equation-oriented simulator originates from the field of thermal power cycle computations, its enhancement by a closely related thermal desalination process enables the integrated basic engineering on cogeneration plants in terms of mass and heat balances. The underlying modeling procedure depicted in the following comprises an evaluation of property data from empirical as well as theoretical sources, the setup of unit operation models for simulating the multi-stage processes and the final creation and calculation of total plant flowsheets.