Biorefinery model for the production of biofuels and bioproducts from lignocellulosic biomass

This work studies advanced biofuel and biomaterials production using lignocellulosic biomass from poplar crops. In this sense, lignocellulosic biomass transformation into biojet fuel, bioLPG, green diesel and High-Density Polyethylene (HPDE) was studied through an exhaustive evaluation, including a techno-economic analysis, a life cycle assessment and physico-chemical and thermodynamical analyses. Biorefinery models were simulated using the chemical engineering software AspenPlus® v.12. In all cases, the NRTL thermodynamical method was employed, except for the HDPE production, where the Polymer method was used for the mass and energy balances. All biorefineries were fed with 77 t/h of feedstock. On the one hand, in the biojet fuel set-up, the biorefinery produced 92,400 t/year of biojet fuel and 39,917 t/year of green diesel. On the other hand, in the HDPE configuration, 103,000 t/year of HPDE were obtained. The life cycle analysis (LCA), carried out using the simulation software SimaPro® and the Ecoinvent® database, measured the environmental impact generated, kg of CO2-eq/MJ biofuel and kg of CO2-eq/kg of HDPE, at each process. Techno-economic results evaluated the relation between fixed and variable costs through a cash flow to obtain the products' minimum selling price (MSP). Even though economic competitiveness is barely achieved, when the processes by-products such as lignin are considered, the MSP drops enough to be competitive with their conventional counterparts. Besides, a sensitivity analysis was performed to evaluate different scenarios where the simulated biorefineries were competitive, demonstrating the potential of poplar biomass residues as feedstock. In all cases, the CO2-eq footprint was compared with European standards, obtaining encouraging results compared to the Renewable Energy Directive II, which means the produced biofuels are eligible for financial support by public authorities. Finally, biofuels properties were compared to the American Society for Testing and Materials (ASTM) standards, where the specifications of road transport fuels and aviation turbine fuels are shown (consisting of a conventional and synthetic mixture). All biofuels met the standards.