AbstractFeasible operating conditions are obtained for an azeotropic distillation tower using a nonlinear programming algorithm. The boil‐up rate, fractional recovery of product, and bottoms purities of entrainer and by‐product are adjusted to locate an overhead vapor stream that condenses into two liquid phases, but is in equilibrium with a single liquid phase on the top tray. A new objective function is introduced and minimized, subject to inequality constraints, using Powell's algorithm (1977). Results are obtained for dehydration of alcohol with benz