(381a) Including Sustainability and Environmental Impact Assessment into Process Design Education: a Case Study Example

Sustainability and the effect chemical processes have on the environment has become a topic of considerable interest in recent years. Because of this, it is increasingly important to include these topics in the process design education of chemical engineering students. This contribution will propose a simple methodology for incorporating sustainability and environmental impact assessment into typical student design problems. This is important since the design engineer has the greatest opportunity to influence the overall sustainability and environmental impact of a chemical process in the conceptual design stage. Therefore, an assessment of these factors should be included into the standard design heuristics commonly employed to develop conceptual process options. This contribution will illustrate, by case study example, how an assessment of the sustainability and potential environmental impact can be included in a typical student design problem.

The case study example considered to illustrate this technique will be based on developing processes for the manufacture of industrial chemical products from the glycerol generated as a byproduct of the manufacture of biodiesel. In terms of energy production, biodiesel has been shown to have an overall positive lifecycle energy balance. Therefore the use of biodiesel and its byproducts may have a positive impact on global climate change. Recently published estimates predict that the demand for biodiesel will grow from 6 to 9 million metric tons per year in the United States and from 5 to 14 million metric tons per year in the European Union in the next few years. However, for every 9 kilograms of biodiesel produced, 1 kilogram of crude glycerol is formed as a byproduct. Due to its high viscosity, glycerol must be removed from the biodiesel product, thus reducing the carbon utilization. Therefore, the identification of novel industrial uses for this glycerol is important to the economic viability of biodiesel.

In this class room case study example, the Waste Reduction (WAR) Algorithm, developed by the U.S. Environmental Protection Agency will be integrated into the conceptual design of two alternative processes for the manufacture of industrial chemical products via the catalytic dehydration of glycerol. It will be shown, that by using this proposed methodology, the choices made during conceptual process development can include sustainability and potential environmental impacts, while not neglecting the important economic considerations typically used to guide the selection of the preferred process option.

Additionally, the environmental impacts of the inclusion of heat integration using thermal pinch analysis will also be considered. Using the case study example, it will further be shown that by including environmental considerations during heat integration activities, a true optimum based on energy, economics and environmental considerations can be achieved.