From wood to resin-identifying sustainability levers through hotspotting lignin valorisation pathways

The concept of bioeconomy supports the diversification strategies of forest-based industries to create new value chains and contribute to economic growth and sustainability. The use of side streams or by-products of the pulp and paper industry (PPI) is seen as a promising approach. In line with this, the idea of substituting fossil-based materials and products is frequently discussed. One such example is the use of lignin as a bio-based alternative for fossil-based phenols. Lignin-based products not only have to fulfil identical technical requirements as their fossil-based counterparts, they are also expected to be more sustainable. This study conducts an integrated hotspot analysis of two lignin valorisation pathways during R & D. The analysis considers the provision of technical kraft lignin as a by-product of a state-of-the-art kraft pulp mill, followed by valorisation, either via solvent fractionation or via base-catalysed depolymerisation (BCD), and the final application of the valorised lignins in phenol formaldehyde resins. As a two-step approach, first of all, the environmental hotspots (e.g., energy-intensive process steps) along the valorisation pathways are identified. Secondly, a variation analysis is carried out, which involves the identification of sustainability levers (e.g., selection of solvents). Identifying those levers at an early research stage helps to support the R & D process towards sustainable product development.