Integrated Energy-Environment-Economy Assessment Of Biofuel From Lignocellulose

Lignocellulosic biomass resources are abundant in China,while petroleum resources are relatively scarce.The production of liquid fuel from lignocellulosic biomass is not only a recycling utilization of waste,but also of great significance to China's energy security.At present,various technologies of lignocellulosic biomass liquefaction are slow in progress.From a macro perspective,to discover and pinpoint the most difficult obstacle in practice is conducive to industrial development and commercial application.Research was carried out from the integrated dimension of energy-environment-economy,with three relatively mature technologies selected as the research objects: biochemical conversion to cellulose ethanol,fast pyrolysis and supercritical ethanol upgrading to bio-oil,and gasification and Fischer-Tropsch synthesis to bio-jet fuel.Process simulation models were established on Aspen plus software,to obtain parameters of material flow,energy flow and thermodynamic data,as the basis for subsequent analysis and calculation.In terms of energy utilization,the exergy analysis method was applied,to calculate the efficiency and irreversible energy loss of each part in the production process of liquid biofuel.The results show that the external exergy loss of the system is small,while the exergy destruction is relatively high due to the irreversible factors inside the system.The energy conversion rates of the three systems are 42.40%,47.37% and 37.44%,and the exergy efficiency are 45.09%,59.02% and 40.74%,respectively.In terms of environmental impact,life cycle assessment was applied to calculate the environmental impact potential of every process in life cycle,including upstream and downstream of the production.The results show that all the three routes have better environmental performance than fossil gasoline,and the bio-jet fuel has the best environmental performance.In addition,replacing fossil materials with renewable hydrogen and bioethanol can improve the overall environmental impact.In terms of economy,the techno-economic analysis method was applied to calculate the fixed capital investment and total production cost of each route.The total production costs of cellulosic ethanol,bio-oil,and bio-jet fuel are about 8600,6600,and 11,000 yuan/ton,respectively.The results show that none of the three bio-liquid fuels currently have economic advantages,and the economics of pyrolysis and upgrading bio-oil are the best in three.