Canadian Journal of Chemical Engineering, Vol.95, No.7, 1313-1322, 2017
An effective pseudospectral optimization approach with sparse variable time nodes for maximum production of chemical engineering problems
An effective pseudospectral method is proposed for dynamic optimization problems, the aim of which is to maximize production of these problems in chemical engineering. Several variable time nodes are considered to be optimization variables in the whole time horizon to obtain a precise localization of the switching points of the optimal control profiles. To ensure accuracy, the intervals between the variable time nodes are further divided into multiple subintervals uniformly. Then the state and the control vector are all parameterized. To improve the efficiency, the sensitivities of the states with respect to the controls and the variable time nodes are derived from the solution of the discretized dynamic system. Three chemical dynamic optimization problems are tested as an illustration. The detailed comparisons between the proposed method and the methods reported in the literature are also carried out. The research results reveal the effectiveness of the proposed approach.