Crawford Jordan T, Shan Chin Wei, Budsberg Erik, Morgan Hannah, Bura Renata, Gustafson Rick
University of Washington, Seattle, WA USA.
School of Environmental and Forest Sciences, University of Washington, Box 352100, Seattle, WA 98195-2100 USA.
Biotechnol Biofuels. 2016 Jun 23;9:141. doi: 10.1186/s13068-016-0545-7. eCollection 2016.
Infrastructure compatible hydrocarbon biofuel proposed to qualify as renewable transportation fuel under the U.S. Energy Independence and Security Act of 2007 and Renewable Fuel Standard (RFS2) is evaluated. The process uses a hybrid poplar feedstock, which undergoes dilute acid pretreatment and enzymatic hydrolysis. Sugars are fermented to acetic acid, which undergoes conversion to ethyl acetate, ethanol, ethylene, and finally a saturated hydrocarbon end product. An unfermentable lignin stream may be burned for steam and electricity production, or gasified to produce hydrogen. During biofuel production, hydrogen gas is required and may be obtained by various methods including lignin gasification.
Both technical and economic aspects of the biorefinery are analyzed, with different hydrogen sources considered including steam reforming of natural gas and gasification of lignin. Cash operating costs for jet fuel production are estimated to range from 0.67 to 0.86 USD L depending on facility capacity. Minimum fuel selling prices with a 15 % discount rate are estimated to range from 1.14 to 1.79 USD L. Capacities of 76, 190, and 380 million liters of jet fuel per year are investigated. Capital investments range from 356 to 1026 million USD.
A unique biorefinery is explored to produce a hydrocarbon biofuel with a high yield from bone dry wood of 330 L t. This yield is achieved chiefly due to the use of acetogenic bacteria that do not produce carbon dioxide as a co-product during fermentation. Capital investment is significant in the biorefinery in part because hydrogen is required to produce a fully de-oxygenated fuel. Minimum selling price to achieve reasonable returns on investment is sensitive to capital financing options because of high capital costs. Various strategies, such as producing alternative, intermediate products, are investigated with the intent to reduce risk in building the proposed facility. It appears that producing and selling these intermediates may be more profitable than converting all the biomass into aviation fuel. With variability in historical petroleum prices and environmental subsidies, a high internal rate of return would be required to attract investors.
对一种基础设施兼容的烃类生物燃料进行了评估，该燃料根据2007年美国《能源独立与安全法案》和《可再生燃料标准》（RFS2）有望被认定为可再生运输燃料。该工艺使用杂交杨树原料，先进行稀酸预处理和酶水解。糖类被发酵成乙酸，乙酸再转化为乙酸乙酯、乙醇、乙烯，最终得到饱和烃类终产物。不可发酵的木质素流可用于燃烧产生蒸汽和电力，或进行气化以生产氢气。在生物燃料生产过程中，需要氢气，可通过包括木质素气化在内的多种方法获得。
分析了生物炼制厂的技术和经济方面，考虑了不同的氢气来源，包括天然气蒸汽重整和木质素气化。根据设施产能，喷气燃料生产的现金运营成本估计在每升0.67至0.86美元之间。以15%的贴现率计算，最低燃料销售价格估计在每升1.14至1.79美元之间。研究了每年生产7600万升、1.9亿升和3.8亿升喷气燃料的产能。资本投资在3.56亿至10.26亿美元之间。
探索了一种独特的生物炼制厂，以从绝干木材中高产率地生产烃类生物燃料，产量为330升/吨。该产量的实现主要得益于使用了产乙酸细菌，这些细菌在发酵过程中不会产生二氧化碳作为副产物。生物炼制厂的资本投资很大，部分原因是生产完全脱氧燃料需要氢气。由于资本成本高，要实现合理的投资回报，最低销售价格对资本融资方案很敏感。研究了各种策略，如生产替代中间产品，以降低建设拟建设施的风险。看来生产和销售这些中间产品可能比将所有生物质转化为航空燃料更有利可图。鉴于历史石油价格和环境补贴的变化性，需要较高的内部收益率来吸引投资者。
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