Hybrid optimization approach for water allocation and mass exchange network

This study deals with the synthesis problem of mass exchange networks (MENs) with treatment option for waste minimization and minimal fresh solvent usage by adopting a hybrid combined graphical and mathematical programming approach based on state-space representation. A simple strategy has been proposed for the synthesis water allocation and mass exchange network (WAMEN), aiming at total recycle of effluent thus subsidizing the fresh water consumption to zero. The network synthesis problem has been decomposed into two main steps: (1) synthesizing a network candidate with simpler graphical tools and presenting in state-space representation (2) considering the state-space representation as an initial guess, the available results are formulated as a MINLP problem and the entire network is optimized. Optimized wastewater network along with mass exchange network for an oil refinery process is generated, illustrating the effectiveness of the proposed methodology. This simple procedure will be a useful tool for process engineers to design self-sustained solvent using networks with zero effluent discharge.