Using GREENSCOPE indicators for sustainable computer-aided process evaluation and design

• GREENSCOPE method and tool further educational and industrial sustainability.
• Information on dimensionless scale with best-target and worst-case indicator limits.
• Example process of oxidation of toluene, shows tradeoffs and why they occur.
• Total utility objective function calculated with GREENSCOPE indicator scores.
• Total utility depends on only marginal rates of substitution and indicator scores.

Manufacturing sustainability can be increased by educating those who design, construct, and operate facilities, and by using appropriate tools for process evaluation and design. The U.S. Environmental Protection Agency's GREENSCOPE methodology and tool, for evaluation and design of chemical processes, suits these purposes. This work describes example calculations of GREENSCOPE indicators for the oxidation of toluene and puts them into context with best- and worst-case limits. Data available from the process is transformed by GREENSCOPE into understandable information which describes sustainability. An optimization is performed for various process conversions, with results indicating a maximum utility at intermediate conversions. Lower conversions release too much toluene through a purge stream; higher conversions lead to the formation of too many byproducts. Detailed results are elucidated through the context of best- and worst-case limits and graphs of total utility and GREENSCOPE indicator values, which are calculated within an optimization framework for the first time.