A sustainable wood biorefinery for low–carbon footprint chemicals production

TLDR

Efficient feedstock use is key to the profitability and sustainability of future biorefineries, making lignin valorization essential when using wood. The integrated biorefinery employs reductive catalytic fractionation to produce a carbohydrate pulp for bioethanol and a lignin oil, which is then extracted and gas‑phase hydroprocessed and dealkylated to yield 20 wt % phenol and 9 wt % propylene, while the remaining 30 wt % phenolic oligomers are repurposed as printing‑ink substitutes for para‑nonylphenol. The process converts 78 wt % of birch into xylochemicals, and techno‑economic and life‑cycle assessments indicate economic competitiveness and a lower CO₂ footprint than fossil‑based production.

Abstract

The profitability and sustainability of future biorefineries are dependent on efficient feedstock use. Therefore, it is essential to valorize lignin when using wood. We have developed an integrated biorefinery that converts 78 weight % (wt %) of birch into xylochemicals. Reductive catalytic fractionation of the wood produces a carbohydrate pulp amenable to bioethanol production and a lignin oil. After extraction of the lignin oil, the crude, unseparated mixture of phenolic monomers is catalytically funneled into 20 wt % of phenol and 9 wt % of propylene (on the basis of lignin weight) by gas-phase hydroprocessing and dealkylation; the residual phenolic oligomers (30 wt %) are used in printing ink as replacements for controversial para-nonylphenol. A techno-economic analysis predicts an economically competitive production process, and a life-cycle assessment estimates a lower carbon dioxide footprint relative to that of fossil-based production.