Improving sustainability of biomass value chains through process intensification : do we always go towards inherently safer design ?
Abstract
It is well known that process and economic constraints due to complexity of biomass conversion as well as low cost of fossil fuels context significantly affect the sustainability of biorefining. Ways to tackle such difficulties can be a) operating biorefineries with biomass from waste streams b) producing main or side streams of new molecules or materials with very high added values c) designing biorefinery systems with increased integration of processes, process streams, coproducts and energy and material recycling d) in connection with point c) or not, making extensive use of local or global process intensification. The objective of the present work is to focus and outline the potential conflicts in terms of safety that may arise with the improvement of global sustainability target. Indeed, it is often considered that intensification is necessarily leading to inherently safer production systems. Through a review of literature on the concept of intensification, first promoted by Hendershot and coworkers in the early 80’s and Inherently Safer Design or Engineering (ISD by Keltz in 1978) a key way to consider safety in early stage of process design, the potential impacts on safety of the process is addressed in this work. Illustrations and discussions through examples are provided, outlining the repercussion of intensification (like activating corrosion issues or triggering risks in effluent or emission treatment units).