Simultaneously targeting for the minimum water requirement and the maximum production in a batch process

This work proposes a multiple objective formulation to simultaneously target the minimization of fresh water requirement and the maximization of production in a batch process. The proposed mixed integer linear programming formulation includes scheduling (such as allocation constraints, time constraints, capacity constraints, mass balances, etc.) as well as fresh water minimization constraints (such as concentration, flow requirements, etc.) and illustrated through an example. The trade-offs between the production and the fresh water requirement is captured through the Pareto optimal front. The Pareto optimal front consists of discrete points and facilitates decision maker to select an appropriate operating point based on other process constraints. Furthermore, it has been demonstrated that due to non-convexity of the model, weighted objective method fails to identify all the Pareto optimal points.