Process synthesis and analysis for catalytic conversion of lignocellulosic biomass to fuels: Separate conversion of cellulose and hemicellulose using 2-sec-butylphenol (SBP) solvent

We developed a strategy for the catalytic production of liquid hydrocarbon fuels (butene oligomers) from cellulose and hemicellulose, which are the major fractions of lignocellulosic biomass. In this strategy the cellulose and hemicellulose fractions are separated through a pretreatment step and then converted to levulinic acid (LA) by monophasic and biphasic reactions using 2-sec-butylphenol (SBP) solvent respectively. The LA is upgraded catalytically to γ-valerolactone (GVL), and subsequently to butene oligomers. To design the integrated strategy, we developed separation subsystems to satisfy the optimized feed concentration for catalytic conversions and to recycle solvents (SBP). To satisfy energy requirements for our process from combustion of biomass residues, we designed a heat exchanger network (HEN) for minimum energy consumption by maximizing heat recovery from the process streams. Our technoeconomic evaluation shows that the integrated strategy using corn stover feedstock results in a minimum selling price of $3.71 per gallon of gasoline equivalent for butene oligomers if using the best possible parameters.