Lignin valorization in biorefineries: A techno-economic analysis of a novel process for biolubricant production from lignin and waste cooking oil

This work aims at preliminary evaluating the techno-economic feasibility of a biolubricant production process starting from lignin and waste cooking oil, to be integrated in a lignocellulosic biorefinery. A phenyl-branched FAMEs mixture is obtained, which exhibit improved lubricity and oxidative stability compared to standard FAMEs-based biolubricants. The product is obtained exploiting aromatic hydrocarbons from lignin, generated via hydrothermal liquefaction followed by selective hydrodeoxygenation. The economic analysis compares the minimum ethanol selling price (MESP) of a generic U.S. biorefinery processing 2000 tonne/day of corn stover with and without the integration of biolubricant production. Results indicate potential improvement in the biorefinery economic performance, with MESP decreasing from $0.798/L in the reference case (ethanol production only) to $0.697/L when the biolubricant process is included. Reduction in the price of waste cooking oil improves the performances, although the biolubricant selling price has a large impact on the economic profitability of the process. • A novel process to valorize lignin from bio-ethanol production is proposed. • Hydrothermal liquefaction of lignin resulted in high yield of phenols. • Phenlyl-branched biolubricant is obtained from lignin-derived aromatic hydrocarbons. • The novel process improves the economic performances of existing biorefineries. • Minimum ethanol selling price is strongly influenced by biolubricant selling price.