Design of environmentally benign processes: integration of solvent design and separation process synthesis

This paper presents a hybrid method for design of environmentally benign pr ocesses. The hybrid method integrates mathematical modelling with heuristic approaches to solving the optimisation problems related to separation proc ess synthesis and solvent design and selection. A structured method of solu tion, which employs thermodynamic insights to reduce the complexity and siz e of the mathematical problem by eliminating redundant alternatives, has be en developed for the hybrid method. Separation process synthesis and design problems related to the removal of a chemical species from process streams because of environmental constraints are particularly suited for solution with the hybrid method. Application of the hybrid method is highlighted thr ough two illustrative examples. The first example involves the determinatio n of an optimal flowsheet for the removal of a chemical species from an aze otropic mixture and the second example involves the determination of enviro nmentally benign substitute solvents for removal of a chemical species from wastewater. (C) 1999 Elsevier Science Ltd. All rights reserved.