Optimization on distillation via piecewise linear approximation

Distillation is very important in process industry, and the optimization aiming to energy saving and yield improvement is still important and difficult. Piecewise linear approximation is firstly introduced into traditional Chemical Engineering field. And therefore, a novel surrogate optimization strategy based on piecewise linear approximation for distillation, is developed in this paper. The nonlinear character has been approximated by a surrogate model based on continuous piecewise linear function. Then the original nonlinear optimization has been transformed into piecewise linear programming (PLP). The PLP problem is solved to get the new operating point for the control scheme. Some properties of PLP are discussed and a condition of local optimum is given. An algorithm for PLP is also proposed, with a distillation process model based on adaptive hinging hyperplane. The statistics show that the new strategy is feasible and effective.