Optimal retrofit design of multi-product batch plants

Abstract: "The problem of retrofit design of multiproduct batch plants is considered in which the optimal addition of equipment to an existing plant must be determined in view of changes in the product demands. In order to circumvent the combinatorial problem of having to analyze many alternatives the problem is formulated as a mixed-integer nonlinear program (MINLP) and solved with the outer-approximation algorithm of Duran and Grossmann. By using suitable variable transformations and approximations, the global optimum solution is guaranteed. The proposed MINLP model is also extended to the case when time-varying forecasts for product demands are given. Numerical examples are presented."