A Prototype Methodology for Incorporating Sustainability Indicators in Biorefinery Process Design

Biorefineries are industrial plants that integrate equipment and processes to transform biomass into a range of biofuels, platform chemicals, end-use products, and energy. The biorefinery concept rises to address two concerns, mainly: assuring energy security (by displacing fossil fuels usage, and adequate stewardship of biomass resources) and reducing greenhouse gases emissions (to meet well specified targets). Traditional methodologies for chemical processing plants are commonly used to design biorefineries, but these fall short on considering these basic criteria systematically during the design process. In this work, a methodology for including various sustainability indicators into the traditional design of biorefinery plants. The two main drivers of biorefineries are included, along with other sustainability indicators, so that a quantitative ‘sustainability footprint’ can be calculated for each design as a standalone evaluation. This methodology consists of 9 indicators for the design stage, and 5 more for the ex-post evaluation of existing biorefineries. For its application it requires performing a Life Cycle Assessment during the conceptual design stage, and a techno-economical pre-feasibility study during the basic engineering stage. A normalized scale is proposed for all the indicators, requiring the identification of the ‘ideal sustainability’ and ‘critical’ states for each one. A case study illustrating the resulting sustainability footprint is presented and discussed.