Techno-economic and life cycle assessment of a wood chips-based organosolv biorefinery concept for the production of value-added phenolic monomers from lignin using an optimized base-catalysed-depolymerisation (BCD) approach.

Authors
Zeilerbauer, Lukas; Lindorfer, Johannes; Suess, Raphaela; Kamm, Birgit

Abstract
A novel approach to base-catalysed depolymerisation (BCD) of organosolv lignin into monomers and oligomers while maximizing yields and minimizing coke formation by Suess et al was scaled up in a theoretical wood-based biorefinery with a yearly input of 40,000 tons of wood chips. Other process steps were modelled from literature and combined with the data obtained from the scale up. Moreover, a novel work up approach was tested under laboratory conditions and then implemented into the model and compared to another simulation-based approach utilizing a novel pervaporation technique, as described by Meng et al. The results were subjected to life cycle assessment (LCA) and a techno economic evaluation. The LCA showed that the biorefinery as a whole provides a significantly lower GWP (excluding biogenic carbon) than the fossil references. The same is shown for the majority of midpoint categories. However, after allocating the GWP potentials, it became evident that subsequent conversions of the C6-fraction to value-added products is a necessity to further optimize the results. The discounted cash flow analysis for biorefinery set ups (40 to 400 kilotons per year) is not profitable with prices based upon fossil references. However, when using higher prices from literature, such as 1,615 € for monomers, 2,000 € for oligomers and 510 € for C6-sugars a positive NPV can be reached at around 100,000 -120,000 tons processed annually.