Feasible specifications in azeotropic distillation



Feasible 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 benzene.