Framework for sustainability metrics

This work presents the application of a new framework for sustainability metrics to industrial processes, in particular, to chemical processes. The sustainability of an industrial process can be evaluated using a set of three-dimensional (3D) indicators that represent all three dimensions of sustainability: economic, environmental, and societal. The four 3D metrics proposed in this worknamely, material intensity, energy intensity, potential chemical risk, and potential environmental impactare applicable to a wide range of process systems. The first two metrics are associated with the process operation. The remaining two metrics, potential chemical risk and potential environmental impact, respectively represent chemical risk to human health in the process environment, and the potential environmental impact of the process on the surrounding environment. To illustrate this framework and the applicability of the proposed set of 3D metrics, two case studies are presented: chlorine production process using three different alternatives (membrane, diaphragm, and mercury cells), and the separation of an acetone/chloroform mixture by two different solvents (benzene and methyl-n-pentyl-ether). Results of this study show that this framework can be effective in selecting the more-sustainable process by comparing process alternatives.