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A process boundary based approach to separations synthesis

Thomas Gilbert Pressly, University of Massachusetts Amherst


Process boundaries and difficult regions for separation units limit the feasible products and recovery of those products. When process boundaries are encountered, a separating agent and or combinations of different types of equipment are used. In this manner, a number of steps are used collectively to meet the separations objective. One type of equipment configuration, the distillation-membrane hybrid, has been studied for binary and multicomponent systems. In this hybrid, the distillation column performs the bulk of the separation, because of the favorable economics of distillation. The membrane is used to bypass the process boundaries and difficult regions. Methods for applying and screening these hybrids were developed. Several configurations were examined conceptually. Case studies were performed on the following systems: water-acetic acid, ethanol-water, propylene-propane, benzene-heptane-octane, methanol-ethanol-water. Separations synthesis using all possible separation units (crystallization, membranes, distillation, decantation, extraction, etc.) was then examined. A design methodology for generating flowsheets of process alternatives to separate multicomponent systems was developed based on representing process boundaries with linear hyperplanes. This approximation allowed the generation of process alternatives using relatively simple calculations.

Subject Area

Chemical engineering|Systems design

Recommended Citation

Pressly, Thomas Gilbert, "A process boundary based approach to separations synthesis" (1998). Doctoral Dissertations Available from Proquest. AAI9841916.