(288e) Life-Cycle Energy Use and Greenhouse Gas Emissions of Biofuels Production from Sweet Sorghum

Sweet sorghum is a promising feedstock to produce renewable and sustainable biofuels to alternative fossil fuels. Utilizing the juice, grain and bagasse to produce bioethanol has been studied extensively. In this study, the life-cycle energy use and green house gas (GHG) emissions of biofuels production from sweet sorghum based an advanced solid state fermentation technology (ASSF) is discussed. The bagasse obtained from ASSF fermentation was converted into diverse biofuels by various conversion pathways such as burning, anaerobic fermentation, enzymatic saccharification fermentation. The final productions were power, biogas and bioethanol. The distillation process of ethanol in ASSF stage was slightly adjusted according to different conversion pathways.

All the biofuels production from sweet sorghum based ASSF can achieve fossil energy saving, especially the biofuel-biogas pathway. Compared to GHG emissions from conventional gasoline, bioethanol-biogas production can reduce GHG emission above 70%. If the fertilizer for planting sweet sorghum is replaced partially by the biogas slurry and residues, the reduction increased further.

The results of this paper provide a comprehensive insight into life-cycle energy use and GHG emissions of multiple biofuels production pathways from sweet sorghum. It is benefit to evaluate the proper integrated process for biofuels production from sweet sorghum based the local planting condition and consideration of capital investment.