(790a) A Comparison of the Recoverability of Organic Solvent Mixtures in Waste Streams Using Process Simulation and Life Cycle Assessment Software

Through the support of the U.S. Environmental Protection Agency and in partnership with Pfizer Inc., a flexible modeling tool that calculates avoided Life Cycle Assessment (LCA) emissions and Operative Cost Savings of solvent recovery systems for low volume pharmaceutical synthesis waste streams was developed. This new tool allows for a rapid assessment of the recoverability of solvent mixtures. ASPEN® Simulation Workbook was used for process modeling. Preliminary environmental impact was determined using SimaPro® and EcoSolvent® by comparing the proposed solvent recovery to the incineration of solvent waste and the manufacture of virgin solvent. Different homogeneous binary (azeotropic and non-azeotropic) solvent-solvent and water-solvent systems were analyzed. The proposed solvent mixtures are representative of those found in pharmaceutical manufacturing and include acetone, acetonitrile, toluene, tetrahydrofuran (THF), isopropyl alcohol, n-hexane, and methyl ethyl ketone (MEK). 

The solvent recovery process model includes distillation, pervaporation (PV) and a combination of both. Sensitivity analysis for different system parameters such as reflux ratio and feed location was performed in several case studies, and points of minimum emissions and operating costs were also determined.