A new software tool to environmentally and economically evaluate solvent recovery in the pharmaceutical industry

The environmental impact reduction and operating costs savings associated with the purification and reuse of solvent waste in the manufacture of active pharmaceutical ingredients (API\u27s) were investigated. A software toolbox has been developed that combines Aspen Plus(R) process simulation with SimaPro(R) and Ecosolvent life cycle assessment (LCA) databases. The feasibility of a relatively small flexible skid capable of recovering multiple solvent waste streams was evaluated. Fractional distillation and pervaporation were considered to separate binary solvent waste mixtures. Optimum distillation reflux ratio and feed stage were determined to maximize the environmental impact reductions and operating cost savings. The optimum reflux ratio was significantly higher than suggested by traditional heuristics. The emissions and cost reductions obtained were as much as 43 % and 59 % higher, respectively, as compared to using the conventional optimum reflux ratio. A comprehensive cash flow analysis showed that the recovery of low volume solvent waste streams can be economically feasible, despite traditional thinking. It has been demonstrated that the flexibility of a skid to recover solvent waste streams of different thermodynamic nature and volume is a key issue to increase profitability. Four case studies from Pfizer are presented to show how our software tool can aid in green engineering decision making