Development of a decision-making framework incorporating safety, environment, and economic criteria for sustainable process design

Abstract

Increasing global legal requirements and rising environmental costs require the chemical industries to minimize their ecological footprint and enhance safety while ensuring economic viability and stability. Conventional sustainability approaches often address these factors separately, leading to suboptimal decision-making in the process design. Currently, there is a growing awareness of simultaneous consideration of all sustainability approaches at the early stage of process design. The present study introduced a unified multi-criteria decision-making (MCDM) framework to identify the most sustainable process routes for the chemical manufacturing process by integrating three key indicators, i.e., safety, environment, and techno-economics. The safety indicator was developed based on chemical hazards as well as equipment safety. Change in Green Degree a measure of greenhouse gas emission was used to determine environmental impact and payback period on the investment was used as economic indicator. The applicability of the proposed framework was demonstrated through a case study of ‘Acetone Production’ by analyzing three acetone production processes with distinct reaction routes, namely, the IPA route, the Cumene Oxidation route, and the Propylene Oxidation route. Each process route was simulated using Aspen HYSYS and the relevant sustainability metrics were computed based on collected data. The MCDM framework was then employed, particularly utilizing The Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) method to evaluate and rank the process alternatives. Acetone production through propylene oxidation emerges as the most sustainable process alternative, with a relative closeness score (RCS) of 0.92, whereas the cumene oxidation route is marked as the least favorable process alternative (RCS 0.01). The IPA dehydrogenation route has a moderate 0.64 RCS.