Techno economic feasibility study for catalytic butene oligomers production from lignocellulosic biomass using 2-sec-butylphenol solvents

Lignocellulosic biomass is one of the most promising resources for production of transportation fuels. Butene oligomers, which can be used as a gasoline range fuel, can be derived from lignocellulosic biomass. This work performs a techno economic feasibility study for a strategy for catalytic butene oligomers (BO) production from lignocellulosic biomass using 2-sec-butylphenol (SBP) solvents. Our strategy includes the pretreatment step to obtain cellulose and hemicellulose separately from lignocellulosic biomass. After pretreatment, the cellulose fraction can be converted to levulinic acid (LA) by monophasic reaction, while the hemicellulose fraction can be converted to LA by biphasic reaction followed by hydrogenation. The LA is then converted to BO via γ-valerolactone (GVL) and butene production. Moreover, this study designs separation subsystems not only to fit optimized feed concentration for catalytic reactions but also to recycle SBP solvents for the reactions. To minimize energy requirements of the process, a heat exchanger network including heat integration between process streams is designed, and thereby the energy requirements can be satisfied by combustion of biomass residues (lignin). Our strategy has advantages: (1) high biomass-to-fuels yield (37.1%) (2) high biomass-derived intermediate recovery (72-99%) (3) high SBP recovery (99%). Our techno economic evaluation reports that the proposed strategy leads to a minimum selling price (MSP) of $4.38 per gallon of gasoline equivalent (GGE) for butene oligomers using a corn stover feedstock. This study also performs sensitivity analyses for identifying the impacts of four key economic parameters on the MSP and the analyses show that the MSP can be decrease to $3.71 GGE -1 when using best possible parameters. INTRODUCTION Lignocellulosic biomass is a promising feedstock for biofuel production and it comprises of cellulose (C6), hemicellulose (C5) and lignin. [1]. The C6 and C5 fractions of lignocellulosic biomass can be converted to biofuels through catalytic route [2-4], while the lignin is used for heat and power production through combustion [5]. Sen et al. [6-8] showed strategies for production of the liquid hydrocarbon fuel (BO) from the catalytic conversion of the C6 fraction of lignocellulosic biomass. The major drawback in these strategies is a low overall biomass-to fuel yield, because the fuels are produced from the C6 fraction of lignocellulosic biomass and the C5 is used for supplying heat and electricity in the process. To overcome this drawback, this strategy converts C5 components of the lignocellulosic biomass to fuels, thereby increasing the biomass-to-fuels yields of the overall process. According to Gürbüz et al. [9], C5 fraction of lignocellulosic biomass can be converted into furfural (FF) and LA by using biphasic reactors with an 2-sec-butylphenol (SBP) solvent. The LA can be converted to GVL and BO [10]. This study shows a strategy for the process synthesis for catalytic conversion of the C6 and C5 fractions of the lignocellulosic biomass to liquid hydrocarbon fuels and performs a techno economic evaluation. This strategy is mainly based on (1) the catalytic pretreatment subsystem (2) the catalytic C6-to-fuels subsystems including the separation subsystems (3) the catalytic C5-to-fuels subsystems including the separation subsystems. NOMENCLATURE C6 * Cellulose C5 * Hemicellulose SBP 2-sec-butylphenol LA Levulinic acid GVL γ-valerolactone BO Butene oligomers FA Formic acid FF Furfural FFA Furfuryl alcohol SA Sulfuric acid NaCl Sodium chloride H2 # Hydrogen Ru Ruthenium Sn Tin Si Silicon O Oxygen Al Aluminium Cu Copper Mg Magnesium Mt Metric tonne HEN Heat exchanger network GGE Gallon of gasoline equivalent MSP [$/GGE] Minimum selling price * Developed abbreviation # Obtained abbreviation [6], [9], [11], [12] 12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics