Energy And Exergy Analysis Of Bio-Jet Fuel Production From Lignocellulosic Biomass Via Aqueous Conversion

To improve the utilization efficiency of lignocellulosic biomass (corn stalk) for bio-jet production via aqueous conversion, this study proposed an aqueous conversion process by utilization of a part of lignin to generate H-2 for hydrogenation (Case 2). And the common aqueous conversion process with combustion of all lignin as fuel was also studied as the reference case (Case 1). The process simulations based on Aspen Plus and the comparative studies of energy and exergy analyses were carried out between the two cases. Furthermore, the cumulative exergy analysis was applied to assess the complete resource consumptions in the life cycle perspective. The results show that the recovery utilization of waste heat and wastewater can increase the energy and exergy efficiencies (eta(en,Jet) and eta(ex,Jet)) by 139.1% and 57.2%% compared to those under basic condition for Case 1, respectively, and increase by 137.0% and 55.7% for Case 2, respectively. This indicates that the recovery energy mainly belongs to low-quality heat energy. Additionally, Case 1 achieves larger energy and exergy efficiencies than Case 2, but Case 2 possesses higher renewability due to the reduction in the consumption of non-renewable resource in hydrogen production. The exergy analysis combined with life cycle assessment indicates that both cumulative exergy efficiency (psi(CExC,Jet))and renewability of bio-jet fuel production can be significantly enhanced by decreasing the consumption of acid and base chemicals and increasing the recovery rate of methanol. The sensitivity analyses indicate that the conversion efficiency of the platform chemicals (furfural and LA) to bio-jet fuel and the consumption of stripping steam significantly affect both eta(ex,Jet) and psi(CExC,Jet).