| The promotion and application of biomass-to-liquid fuel technology can effectively reduce greenhouse gas emissions in the transportation sector,which is a great impetus to achieve the "double carbon" goal.At present,biomass-to-liquid fuel technologies are divided into four basic routes: fermentation,hydrothermal,pyrolysis and gasification,with various technologies but slow commercialization progress.With bioethanol and biofuel as the target products,the three routes of poplar fermentation for ethanol production,corn stover hydrothermal for jet fuel production and biomass gasification-olefin-polymerization for jet fuel production,were selected as research subjects among basic routes.Futher,a cross-coupled route based on lignin conversion was designed in the corn stover fermentation route.Aspen Plus software was used for process design and process simulation of the above routes,and evaluation studies and comparative analysis of each route were carried out based on simulation data in three dimensions: energy,environment,and economy(3E).For the fermentation route of poplar to ethanol,the route was desigened based on the delignification strategy and 3E assessment was conducted.The energy conversion rate of the route is 35.78%,the energy efficiency is 41.42%,and the carbon efficiency is 40.8%.The carbon and energy losses of the system mainly come from the removal of lignin and the combustion of residues.Environmentally,the environmental impact of the system mainly comes from the use of sodium chlorite in the pretreatment stage.When wind power is used as the power supply for the sodium chlorite production process.As a result,the environmental performance of the route could be effectively improved when wind power is used as the power supply for the sodium chlorite production process.Economically,the use of feedstock,enzymes,and sodium chlorite are responsible for the high minimum fuel price(MFSP)of ethanol in this route.The results of the sensitivity analysis indicate that increasing the ethanol yield and reducing the use of sodium chlorite are effective in improving the overall performance of the system.For the hydrothermal route of corn stover to jet fuel,two schemes of adding furfural(S-HJ)and not adding furfural(S-HJ-NF)were considered for 3E assessment and comparative study.The results of the energy evaluation indicate that the carbon loss and energy loss of the system mainly occurred in the lignin combustion process.Comparing to the S-HJ-NF,the S-HJ improves the energy conversion rate,energy efficiency,and carbon conversion rate by 12%,8%,and 4%,respectively.Environmentally,the addition of furfural causes an increase in the environmental impact of the system because of the introduction of indirect environmental impacts.The use of hydrogen is the main cause of the environmental impact of the system,and therefore different sources of hydrogen have a large impact on the environmental aspects of the system,among which the environmental performance of the system is optimal when wind power electrolytic water hydrogen production is used as the hydrogen supply of the system.Economically,the high price of purchased furfural resulte in higher jet fuel production cost and MFSP of S-HJ than S-HJ-NF by 17% and 11.7%,respectively.The results of the sensitivity analysis indicate that improving the jet fuel production rate and reducing hydrogen use would be effective in improving the overall system performance.For the gasification-olefin-polymerization route of biomass to jet fuel,corn stover(S-GJ)and poplar(P-GJ)were selected as the feedstock of the routes.The 3E assessment and comparative analysis was conducted between two schemes mentioned above.The difference in energy index between the two solutions is not significant,and the difference in each index is within 3%.The energy loss of the system mainly occurs in the combustion & vapor system,and the carbon loss mainly occurs in the syngas to olefin process.Environmentally,the environmental impact of the gasification route mainly comes from the jet fuel use phase and the biomass acquisition phase.And the environmental impact of the corn stover planting process is higher than that of the poplar planting process,so the environmental performance of the P-GJ is better than that of the S-GJ.In terms of economics,the jet fuel production cost and MFSP of the S-GJ scheme are 11% and 23.68% higher than those of the P-GJ scheme,respectively.The results of the sensitivity analysis indicate that improving the jet fuel yield and reducing equipment investment are key measures to improve the economics of the system.For the cross-coupling routes,from the perspective of product consistency,the lignin-catalyzed pyrolysis(S-F-LP)to aromatics and lignin gasification-syngas fermentation to ethanol(S-F-LG)routes were designed and compared with the traditional lignin combustion to power(S-F-LC)route.The results show that the cross-coupled route has obvious advantages over the conventional route,and the S-F-LG route has the best performance in terms of 3E.In terms of energy conversion rate,energy efficiency and carbon efficiency,S-F-LG and S-F-LP are 3-6% higher than S-F-LC.Environmentally,each environmental index of both cross-coupled routes is more than 6% lower than that of the basic route.Economically,the MFSP of ethanol in the two cross-coupled routes is 1.7% and4.4% lower than that of the basic route,respectively.The comparison of the 3E assessment results of the above routes were carried outseparately.The results of the energy comparison evaluation indicate that the route based on fermentation technology has the best energy performance,while the hydrothermal route has slightly lower energy efficiency than the gasification route because it does not achieve the full component conversion.Environmentally,the biofuels produced by each route have significant carbon reduction advantages over fossil fuels,with reduction efforts ranging from39-95%.The most significant environmental impact type for each route is AP,and the gasification route has the best environmental performance in terms of environmental performance.Economically,the gasification route has the highest capital investment and the hydrothermal route has the lowest capital investment,and the hydrothermal route has an outstanding advantage in terms of capital investment per unit energy.The MFSP of per unit mass of each route ranged from 5840-16294.5 (?)/t,with the lowest being the S-F-LG route and the highest being the S-HJ route.The MFSP of per unit energy of each route ranged from 0.21-0.378 (?)/MJ,with little difference between the routes.Finally,based on the comparison results,the characteristics of each route are summarized and reasonable suggestions are given for the development of each route based on their respective characteristics. |
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