PRO/II is the flagship offering in SimSci-Esscor's Process Engineering Suite (PES). This steady-state simulator performs rigorous mass and energy balances for a wide range of processes. From oil and gas separation to reactive distillation, PRO/II combines the data resources of a large chemical component library and extensive thermodynamic property prediction methods with the most advanced and flexible unit operations techniques. Process engineers benefit from computational facilities to perform all mass and energy balance calculations needed to model most steady-state processes within the chemical, petroleum, natural gas, solids processing, and polymer industries. PRO/II runs in an interactive Windows®-based GUI environment.