中国石化新闻网讯 据油价网报道，美国国家可再生能源实验室（NREL）的研究人员报告说，他们成功地利用木质素作为一种100%可再生航空燃料的途径。木质素构成植物细胞壁的坚硬部分。植物的其他部分被用于生物燃料，但木质素很大程度上被忽视了，因为它很难被化学分解并转化为有用的产品。
木质素是一种未被充分利用的自然资源，它可能正是航空业控制碳排放所需要的。
来自3个机构的研究人员——美国能源部国家可再生能源实验室(NREL)、麻省理工学院(MIT)和华盛顿州立大学——报告了成功使用木质素作为100%可再生航空燃料的途径。
这份新发表的研究报告展示了研究人员开发的一种从木质素中去除氧气的方法，这样所产生的碳氢化合物就可以用作生物航空燃料混合料。这篇题为《木质素连续加氢脱氧制喷射型芳香烃》的研究报告发表在《焦耳》杂志上。
研究报告的撰写者格雷格·贝克汉姆、安娜·莫莱斯和厄尔·克里斯滕森是NREL的研究人员。
研究报告指出，由于航空业已承诺大幅减少碳排放，这需要使用可持续的航空燃料来源。2019年，全球航空公司消耗了1060亿加仑的航空燃料，预计到2050年，这一数字将翻一番以上。要在同一时期内实现航空业的净碳中和目标，就需要大量使用可持续航空燃料(SAF)，这种燃料与传统燃料的混合限制很高。
航空燃料是不同碳氢化合物分子混合成的混合体，包括芳烃和环烷烃。目前的商业化技术无法生产出符合100%可持续航空燃料标准的这些成分。取而代之的是，SAF混合燃料与传统的碳氢化合物燃料结合。作为自然界中可再生芳烃的最大来源，木质素可能是实现完全生物航空燃料的答案。这份新发表的研究报告说明了木质素途径补充现有和其他发展中的途径的能力。具体来说，在这份新报告中描述的木质素途径允许SAF在更高的混合比下具有燃料系统相容性。
由于木质素在加工上的不适应性，它通常被用于加热和发电，或者只用于低价值的应用。之前的研究已经生产出了含氧量很高的木质素油，含量在27%到34%之间，但要用作航空燃料，这一含量必须降低到0.5%以下。
已经尝试过其他方法来降低氧含量，但所用的催化剂需要昂贵的贵金属，而且被证明产量低。 这3家机构的研究人员展示了一种有效的方法，在连续过程中使用地球富含的碳化钼作为催化剂，实现了大约1%的含氧量。
李峻 编译自 油价网
原文如下：
Researchers Report Renewable Jet Fuel Breakthrough
National Renewable Energy Laboratory researchers report success in using lignin as a path toward a drop-in 100% sustainable aviation fuel. Lignin makes up the rigid parts of the cell walls of plants. Other parts of plants are used for biofuels, but lignin has been largely overlooked because of the difficulties in breaking it down chemically and converting it into useful products.
Lignin is an underutilized natural resource that could be just what the airline industry needs to curb carbon emissions.
Researchers at three institutions – the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL), the Massachusetts Institute of Technology (MIT), and Washington State University – report success in using lignin as a path toward a drop-in 100% sustainable aviation fuel.
The newly published research demonstrated a process the researchers developed to remove the oxygen from lignin, such that the resulting hydrocarbons could be used as a bio jet fuel blendstock. The research paper, “Continuous Hydrodeoxygenation of Lignin to Jet-Range Aromatic Hydrocarbons,” has been published in the journal Joule.
Gregg Beckham, Ana Morais, and Earl Christensen are the researchers involved from NREL.
The paper points to the need to use sustainable sources for jet fuel as the airline industry has pledged to dramatically reduce carbon emissions. Airlines consumed 106 billion gallons of jet fuel globally in 2019, and that number is expected to more than double by 2050. Accomplishing the industry’s goal of achieving net carbon neutrality during that same period will require a massive deployment of sustainable aviation fuel (SAF) with high blend limits with conventional fuel.
Jet fuel is a blended mixture of different hydrocarbon molecules, including aromatics and cycloalkanes. Current commercialized technologies do not produce those components to qualify for a 100% SAF. Instead, SAF blendstocks are combined with conventional hydrocarbon fuels. As the largest source of renewable aromatics in nature, lignin could hold the answer to achieving a complete bio-based jet fuel. This newly published work illustrates the ability of a lignin pathway to complement existing and other developing pathways. Specifically, the lignin pathway described in this new work allows the SAF to have fuel system compatibility at higher blend ratios.
Because of its processing recalcitrance, lignin is typically burned for heat and power or used>Other processes have been tried to reduce the oxygen content, but the catalysts involved require expensive noble metals and proved to be low yielding. Researchers at the trio of institutions demonstrated an efficient method that used earth-abundant molybdenum carbide as the catalyst in a continuous process, achieving an oxygen content of about 1%.