Kumar Amit, Sokhansanj Shahab
Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta, Canada T6G 2G8.
Bioresour Technol. 2007 Mar;98(5):1033-44. doi: 10.1016/j.biortech.2006.04.027. Epub 2006 Jun 23.
This study develops cost, energy input and carbon emissions for a number of switchgrass supply options. The Integrated Biomass Supply Analysis and Logistics (IBSAL) model developed at Oak Ridge National Laboratory is used to evaluate the delivery systems. Three biomass collection systems: baling, loafing and ensiling are evaluated. The number and operational performance of equipment are specified to complete collection operations within 120 days of harvest after August 1. Bales are stacked and tarped on the farm side. The transport of biomass from the farm side to a biorefinery takes place over a full year cycle, i.e. 365 days. Supply quantities range from 454 to 4540 dry tonnes/day (500-5000 dry tons/day). Delivered costs to a biorefinery with capacity of 1814 dry tonnes/day (2000 dry tons/day) are: 44-47 dollars/dry tonne for delivered bales (round and square); 37 dollars/dry tonne for delivered loafs (size 2.4 m x 3.6 m x 6 m); 40 dollars/dry tonne for chopped biomass; and 48 dollars/dry tonne for ensiled chops. These costs do not include any payment to the farmers or switchgrass farming cost. Based on the data from literature, the switchgrass farming cost can range from 30 to 36 dollars/dry tonne. These costs would be additional to the switchgrass collection and transportation cost. Switchgrass collection is generally less expensive than collection of straw or corn stover because of the assumed high yield of 11 dry tonnes/ha and a denser biomass. Energy consumption for delivery systems at this capacity ranges from 4.8% to 6.3% of the energy content of switchgrass. Additional 1% of the energy content of switchgrass is consumed in its farming. At 1814 dry tonnes/day (2000 dry tons/day) capacity, greenhouse gas emissions ranges from 75 to 100 kg of CO2/dry tonne of switchgrass delivered.
本研究针对多种柳枝稷供应方案制定了成本、能源投入和碳排放。使用橡树岭国家实验室开发的综合生物质供应分析与物流（IBSAL）模型来评估输送系统。评估了三种生物质收集系统：打捆、条垛和青贮。明确了设备数量和运行性能，以便在8月1日之后的收获期120天内完成收集作业。草捆在农场一侧进行堆叠并用防水布覆盖。生物质从农场一侧运输到生物精炼厂需经过一整年的周期，即365天。供应数量范围为454至4540干吨/天（500 - 5000干吨/天）。输送到日处理能力为1814干吨（2000干吨）的生物精炼厂的成本为：圆形和方形草捆的输送成本为44 - 47美元/干吨；尺寸为2.4米×3.6米×6米的条垛输送成本为37美元/干吨；切碎生物质的输送成本为40美元/干吨；青贮切碎物的输送成本为48美元/干吨。这些成本不包括向农民支付的任何款项或柳枝稷种植成本。根据文献数据，柳枝稷种植成本可能在30至36美元/干吨之间。这些成本是柳枝稷收集和运输成本之外的额外费用。由于假定柳枝稷高产，每公顷产量为11干吨，且生物质密度较大，因此柳枝稷的收集成本通常低于秸秆或玉米秸秆的收集成本。这种产能下输送系统的能源消耗占柳枝稷能量含量的4.8%至6.3%。柳枝稷种植还会额外消耗其能量含量的1%。在日处理能力为每1814干吨（2000干吨）时，每输送干吨柳枝稷的温室气体排放量在75至100千克二氧化碳之间。
