(458e) Incorporation of Safety and Sustainability in Conceptual Design Via a Return on Investment Metric

Traditionally, process design and selection of alternatives has mainly relied on techno-economic analyses. A general practice is that once a design has been selected, the assessment of other aspects such as environmental impact and process safety implications is carried out at a later stage, at which time limited modifications can be done to the design in order to enhance such performances. Therefore, there is a need for a tool to simultaneously consider economic, environmental and safety objectives during the conceptual design phase of a project. In this work, a new approach for the simultaneous incorporation of process profitability, environmental implications and safety considerations is presented. This approach is based on extending the conventional return on investment (ROI) metric to include positive or negative impacts of potential design changes on the three aforementioned aspects. In particular, a safety and sustainability weighted return on investment metric (SASWROIM) is introduced to systematically integrate those multiple objectives and provide valuable information at the conceptual design stage. To illustrate the usefulness of the proposed approach, two case studies for the production of butadiene and methanol are considered. It is shown how the new metric can be used by decision makers to reliably combine the economic viability of a project with the assorted impact on the environment and safety characteristics of the process.