Designing environmentally friendly chemical processes with fugitive and open emissions

Fugitive or open emissions can dominate the potential environmental impacts of a chemical process. In this work the design and simulation calculations of a process provide an opportunity to visualize relationships between economic potentials and potential environmental impacts. The analysis of the economic and environmental effects of process alternatives are completed quickly and easily using order-of-magnitude costing techniques and the Waste Reduction algorithm for environmental evaluation. In the example studied, the hydrodealkylation of toluene, both the economic and environmental results point towards the alternative of recycling diphenyl to extinction, which is a form of pollution prevention by source reduction. As open emissions are eliminated, the importance of fugitive emissions is shown to increase. Finally, results show where economic optimum and minimal environmental impact designs occur, and therefore one can see tradeoffs between these designs.