The objective of this study was to evaluate the environmental impact of the production of a range of liquid biofuels produced from the combination of fermenting sorghum stalk juice (bioethanol) and the pyrolysis/hydrotreatment of residual bagasse (renewable gasoline and diesel). Life cycle impact assessment (LCIA) was performed on a farm-to-wheels system that included: (i) sorghum farming, (ii) juice extraction, (iii) juice fermenting, (iv) bagasse pretreatment, (v) bagasse thermochemical treatment (pyrolysis, hydroprocessing, and steam reforming), and (vi) typical passenger vehicle operation. LCIA results were compared to those of petroleum fuels providing the equivalent functional unit—cumulative kilometers driven by spark ignition direct injection (SIDI) vehicles utilizing either renewable gasoline or ‘bioE85—a blend of bioethanol and renewable gasoline,’ and a compression ignition direct injection (CIDI) vehicle utilizing renewable diesel produced from 76 tons of harvested sweet sorghum (1 ha). Sweet sorghum biofuels resulted in a 48% reduction climate change impact and a 52% reduction in fossil fuel depletion. Additionally, reduced impacts in ozone depletion and eutrophication were found (67% and 47%, respectively). Petroleum fuels had lower impacts for the categories of non-carcinogenic health impact, smog, respiratory effects, and ecotoxicity, showing tradeoffs between sorghum and petroleum fuels. Overall, sorghum biofuels provide advantages in environmental impact categories including global warming potential, fossil fuel depletion and eutrophication, showing potential for sorghum as a promising second-generation feedstock for fuel.

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美国甜高粱生物燃料生命周期影响评估

本研究的目的是评估由发酵高粱茎汁（生物乙醇）和残留甘蔗渣（可再生汽油和柴油）的热解/加氢处理相结合生产的一系列液体生物燃料的生产对环境的影响。生命周期影响评估 (LCIA) 在农场到车轮系统上进行，包括：(i) 高粱种植，(ii) 榨汁，(iii) 果汁发酵，(iv) 甘蔗渣预处理，(v) 甘蔗渣热化学处理（热解、加氢处理和蒸汽重整），以及 (vi) 典型的乘用车操作。LCIA 结果与提供等效功能单元的石油燃料的结果进行了比较 - 由火花点火直喷 (SIDI) 车辆使用可再生汽油或“bioE85”（一种生物乙醇和可再生汽油的混合物）和压缩点火直喷车辆驱动的累积公里数(CIDI) 车辆利用 76 吨收获的甜高粱（1 公顷）生产的可再生柴油。甜高粱生物燃料使气候变化影响减少了 48%，化石燃料消耗减少了 52%。此外，还发现臭氧消耗和富营养化的影响减少（分别为 67% 和 47%）。石油燃料对非致癌健康影响、烟雾、呼吸系统影响和生态毒性等类别的影响较低，显示出高粱燃料和石油燃料之间的权衡。全面的，