The optimal control problem can be described as follows: for a given multicomponent batch distillation configuration ( N -total number of trays, Pworking pressure), batch composition, the distillation task, and overall time horizon (t f ), determine the optimal reflux ratio so as to maximize the distillate at every step, subject to any constraints (model equations, bounds on the optimization variables). The problem above is a nonlinear programming problem, and, it is solved by the BOCOP solver using direct method with a choice of discretization schemes for dynamics discretization, so to converse the problem into finite-dimensional (Bonnans et al. ).