Economics and Global Warming Potential of a Commercial-Scale Delignifying Biorefinery Based on Co-Solvent Enhanced Lignocellulosic Fractionation to Produce Alcohols, Sustainable Aviation Fuels, and Co-Products from Biomass

Harnessing the natural diversity of plant biomass for producing more economical and environmentally sustainable liquid fuels entails integrating different chemical or biological processes together, each finely tuned for a unique biomass intermediate, to realize greater synergies in a co-processing schema known as biorefining. Presented here is a techno-economic and life cycle analysis of a hybrid biorefinery strategy that maximizes total utilization of lignocellulosic biomass by integrating different leading biological and catalytic processes to produce commercially relevant biofuels and bioproducts. High fidelity computer models were assembled to evaluate the impact of feedstock selection and co-product selection on overall economics and global warming potential of the plant. Central to this model is the use of mild Co-solvent Enhanced Lignocellulosic Fractionation (CELF) pretreatment as the first step to non-destructively fractionate biomass into clean hemicellulose sugars, cellulose, and lignin intermediates that are funneled to a suite of downstream conversion technologies to yield alcohols, esters, carboxylic acids, and hydrocarbons as co-products. By employing a multiparametric evaluation of the processing facilities using deterministic exploration of experimental data and sensitivity analyses, results show the advantages of processing a feedstock with higher carbon content (poplar instead of corn stover) and producing an alcohol with higher yield and titer due to lower toxicity during fermentation (ethanol instead of isobutanol). The supercritical conversion of lignin to cycloalkanes, a potential alternative sustainable aviation fuel (SAF), presents mixed outcomes: while this operation increases the recovery of carbon from biomass, its inclusion in the biorefinery setup leads to a carbon footprint penalty in view of the use of methanol for lignin depolymerization. The analysis also showed the possibility of supplying alcohol-derived SAF to the market at competitive prices - as low as $3.15/GGE (gallon of gasoline equivalent) - as well as carboxylic acids and esters.