(274d) A Sustainable Design Project for the Process Separations Class

Including sustainable design into the core chemical engineering classes is becoming increasingly important. As more and more attention is placed on the effects chemical process have on the global environment, the role of chemical engineers in addressing these concerns in increasing. Therefore, it is important to begin introducing sustainable design concepts early in the chemical engineering curriculum.

This contribution will outline a sustainable design project that can easily be integrated into an undergraduate process separations course. Process Separations is a core course in most curricula, so introducing sustainable design projects here is a good way to integrate these concepts to students. The project described in this contribution is geared towards Junior level students and assumes a basic familiarity with process simulation software packages, such as ASPEN Plus.

The basis for this sustainable design project is a comparison of technology for separating a solvent ? water solution that is known to form an azeotrope. The student design goal is to compare traditional extractive distillation using a liquid entrainer with a system utilizing membrane technology. The students then submit a recommendation for which technology should be chosen, considering economic, environmental and inherently safe design considerations. In making this design choice, not only will students consider the typical tradeoffs of distillation column design, such as energy usage versus number of theoretical stages, they will also consider the potential environmental impacts of each technology and each design choice. The students use the U.S. EPA's Waste Reduction Algorithm as a means of comparing the environmental impacts of their different process options.

By considering the environmental impacts of both processes as well as the economics the students are given a more complete understanding of their design choices, in the context of the Process Separations course. Since it is in the design stage that chemical engineers have the most influence over the final process it is important to begin addressing the kinds of design choices engineers routinely face early and throughout the Chemical Engineering curriculum.