| In the process of aqueous-phase conversion of lignocellulosic biomass to aviation fuel,the lignin is difficult to be hydrolyzed,and usually used as fuel to provide heat,which limits the increase of the yield of aviation fuel.Therefore,it is of great significance for the sustainability of bio-jet fuel production to analyze the energy efficiency and environmental impact of the new process of bio-jet fuel production from full components in biomass.Based on Aspen Plus software,two different pathways of lignin in corn stover to bio-jet fuel via aqueous-phase conversion were simulated:two-step to cycloalkanes from lignin（LJC）and one-step to arenes from lignin（LJA）.Meanwhile,two scenarios of external-supply hydrogen（LJC-C/LJA-C）and self-supply hydrogen（LJC-G/LJA-G）were further explored.Through the energy analysis and exergy analysis,the thermodynamic performances of different systems were compared.Additionly,a life cycle cumulative exergy model was established based on the exergy theory and life cycle assessment.The resource and environmental performance of biomass to bio-jet fuel via aqueous-phase was evaluated by Sima Pro software,which could be optimized through the sensitivity analysis.The results of the thermodynamic performance analysis show that 49.4%and 71.4%of the hydrolyzed biomass are converted to bio-jet fuel in LJA-C and LJA-G,respectively,which are 23.8%and 16.5%higher than LJC-C and LJC-G,respectively.The conversion of biomass into high-quality bio-jet fuel in LJA-G is the most sufficient.Considering the supplemental biomass,the bio-jet fuel yields of LJA-C and LJA-G are 142.7 kg/t-bio and122.0 kg/t-bio,respectively,which are 10.1%and 10.2%higher than LJC-C and LJC-G,respectively.The energy and exergy flows show that the energy loss of the furfural production unit is the largest,followed by the combustion unit.As for the exergy loss,it is concentrated in the combustion unit,which is mainly the irreversible loss.The system thermodynamic performances of LJA are better than that of LJC,and LJA-C has the highest energy and exergy efficiencies,with09),0))and0,0))reaching 34.9%and 31.2%,respectively,and09),)and0,)reaching 45.7%and 33.9%,respectively.However,the LJA-G has the highest energy-quality improvement rate（20.1%）.09),0))and0,0))of LJA are about 12%and 13%higher than that of LJC,respectively,with09),)and0,)of LJA about 7%and 11%higher than that of LJC,respectively.As for the energy-quality improvement rates,LJA-C and LJA-G are increased by 17.3%and 13.6%over LJC-C and LJC-G,respectively.The sensitivity analysis of thermodynamic performance shows that decreasing the mass ratio of steam to furfural（S1）can significantly improve the exergy efficiency of LJC-G and LJA-G.When all these factors reach the ideal values,the maximum bio-jet fuel yield of LJC-G and LJA-G can reach 125.7 kg/t-bio and 136.7 kg/t-bio,0,)can reach 34.2%and 37.6%,respectively.The results of cumulative exergy consumption show that the resource performance of LJA is better than LJC.The optimal,0)and,are existed in LJA-C,which can reach 26.9%and 29.3%,respectively.Compared with LJA-G,the increase of above two indicators can reach 3.7%.With regard to LJC-C,the increase rates of,0)and,exceed 10%,which are 13.1%and 11.1%,respectively.But the system with the highest renewability is LJA-G,withreaching 1.52.The efficiency of the hydrogen production from biomass is lower than that from traditional fossil fuels,but it has the better renewability.Sensitivity analysis of cumulative exergy shows that increasing methanol recovery rate plays a significant role in improving cumulative exergy efficiency and renewability.When all influencing factors under the ideal conditions,the maximum,of LJC-G and LJA-G can reach 31.1%and 33.7%,respectively,and the maximumcan reach 2.14 and 2.46,respectively.According to the environmental impact assessment,the environmental impacts of global warming（GWP）,human toxicity（HTP）,fresh water aquatic ecotoxicity（FETP）,acidification（AP）,and eutrophication（EP）in LJC are greater than that of LJA.The production stage contributes the most to the environmental impact among all stages,followed by the growth stage.The environmental impact of GWP in the growth stage mainly comes from direct emissions,nitrogenous fertilizer,and electricity;while the environmental impacts of AP,HTP,FETP and EP are mainly from nitrogenous fertilizer,electricity,and phosphate fertilizer.Moreover,hydrogen,electricity,H2SO4,and Ca O are the main influencing factors in the production stage.Sensitivity analysis results of environmental impact imply that improving the recovery rate of methanol and reducing the concentration of sulfuric acid can effectively reduce the environmental impact. |
