Simulation And Life-cycleassessment Of Directional Synthesis Of Aviation Kerosene Naphthenes From Biomass

Biomass energy is the only carbon-containing renewable energy that can be converted into liquid fuels.In view of the problem of efficient conversion of biomass into aviation kerosene naphthenes and the environmental impacts caused by pollutants discharge in the life cycle,this paper develops a new pathway that biomass to low carbon aromatics via catalytic pyrolysis,and then to C8-C15 aromatics and naphthenes via aromatics alkylation and hydrogenation saturation reactions,and finally to aviation fuel via the blending.4 systems for the directional synthesis of jet fuel naphthenes from biomass have been established.The 4 systems are:Sys1:Directional pyrolysis of biomass in a fixed bed reactor to prepare C6-C8 aromatics coupled with hydrogenation in a magnetically stirred tank to prepare C8-C15 naphthenes;Sys2:Directional pyrolysis of biomass in a fixed bed reactor to prepare C6-C8 aromatics coupled with fixed bed reactor hydrogenation to prepare C8-C15 naphthenes;Sys3:Fluidized bed rapid pyrolysis-fixed bed catalytic reforming to prepare C6-C8 aromatics coupled with fixed bed reactor hydrogenation to prepare C8-C15 naphthenes;Sys4:Fluidized bed rapid pyrolysis-fixed bed catalytic reforming to prepare C6-C8 aromatics coupling with a magnetically stirred tank to produce C8-C15 naphthenes.The software Aspen Plus was used to model and simulate the 4 systems,and the software Simapro was used to evaluate and compare the life cycle of the 4 systems,so as to obtain the system with the overall optimal product yield and environmental effect.Finally,the adaptability of different types of biomass raw materials in China and Thailand were evaluated,which provides a reference for selecting typical biomass materials in China and Thailand to produce aviation kerosene naphthenes.The results of simulation study show that:Sys2 is the optimal process.Under the optimal production conditions,the output of biomass-based aviation kerosene naphthenic hydrocarbons is 172.66 kg/t wet biomass,the yield is 18.89 wt.%,the minimum system energy consumption is 132.26 k W,and the energy recovery is 213.64k W.The results of life cycle assessment show that when the IPCC 2013 GWP method is used to evaluate the 4 systems,the GWP of Sys2 is the lowest,which is 1.62 kg CO₂-eq/kg aviation kerosene naphthenes and 60.79%lower than that of fossil jet fuel.When the CML 2001 method was used to conduct a comprehensive evaluation of Sys2,it was found that GWP and FDP are the main environmental impact types for the life cycle assessment of the system.Sys2 was taken as the optimal system to study the adaptability of typical biomass from China and Thailand.The results show that when Chinese fir and pine are used as raw materials,the yields of aviation kerosene naphthenes are 18.89%and 14.97%,respectively,and the GWP of the system are 1.24 and 1.33 kg CO₂-eq/kg aviation kerosene naphthenes,respectively.Woody biomass such as Chinese fir and pine are more suitable as raw materials.Among the various biomass raw materials in Thailand,when oak,jatropha residue and rice straw are used as raw materials,the target product’s yields are 15.77%,11.26%,and 3.54%,respectively,and the GWP are 2.03,1.77,and0.79 kg CO₂-eq/kg aviation kerosene naphthenes,respectively.