Increasing Sugar Yield in Biofuel Manufacturing through Control of Cellulosic Biomass Particle Size

今天的经济和社会高度依赖液体燃料作为交通工具。目前，美国使用的90%以上的液体运输燃料是以石油为基础的。当务之急是开发国内生产的、对环境无害的替代液体燃料。从农林残渣和专用能源作物等纤维素生物质中提取的生物燃料提供了中短期最佳替代方案之一。纤维生物质的减量化是生物燃料生产的关键步骤。粒度细化是一个耗能大的过程，而粒度决定了这个过程的能耗。该奖项支持研究，以了解纤维素生物质颗粒大小和生物燃料产量之间的关系。这项研究的成功完成将为未来的生物燃料制造技术奠定基础。这项研究将对生物燃料制造的总体成本和能源平衡产生重大影响，极大地有利于美国经济和能源安全，以及总体上的环境和社会。该项目将对工程教育产生积极影响。将开设一门新课程，并辅之以动手实验课程，以加强本科工程学课程，并让学生参与可再生能源制造的项目。本研究的目的是检验三个假说，以解释纤维素生物质颗粒大小与酶解产糖率之间的关系不一致。在这项研究中，假设不一致是由于使用不同的产糖量定义、粒度范围和前处理方法造成的。这项研究将使用目前流行的生物燃料制造技术和目前行业中使用最广泛的三种纤维素生物质：小麦秸秆、玉米秸秆和柳枝菊。将在实验室和中试规模的生物燃料转化设施上进行实验研究，以验证假设。此外，纤维生物质的结构特征、形态变化和化学组成将通过电子显微镜、X射线衍射分析、紫外光谱、高效液相色谱、红外光谱、西蒙氏染色和核磁共振技术进行表征。基于实验结果，将开发和验证一个包含所有重要的结构、形态和化学特征的产糖量模型。这项研究的结果将对糖类化合物在水解过程中的动态降解提供深入的了解。它将促进在生物燃料制造方面做出战略和运营决策所需的知识库。

Today's economy and society are highly dependent on liquid fuels for transportation. Currently, more than 90 percent of the liquid transportation fuels used in the U.S. are petroleum-based. It is imperative to develop alternative liquid fuels that are domestically produced and environmentally benign. Biofuels, derived from cellulosic biomass such as agricultural and forestry residues and dedicated energy crops, offer one of the best near- to mid-term alternatives. Size reduction of cellulosic biomass is the key step in the manufacturing of biofuels. Size reduction is an energy intensive process, and particle size dictates the energy consumption in this process. This award supports research to understand the relationship between cellulosic biomass particle size and biofuel yield. Successful completion of this research will build a foundation for future biofuel manufacturing technologies. This research will have a significant impact on the overall cost and energy balance of biofuel manufacturing, greatly benefiting the U.S. economy and energy security, as well as the environment and society, in general. This project will have a positive impact on engineering education. A new course accompanied by hands-on lab sessions will be created to strengthen the undergraduate engineering curricula and engage students in participating projects on renewable energy manufacturing. The research objective is to test three hypotheses to explain inconsistency in the relationship between cellulosic biomass particle size and enzymatic hydrolysis sugar yield. In this research, it is hypothesized that the inconsistences are caused by the use of different sugar yield definitions, particle size ranges, and pretreatment methods. The prevailing biofuel manufacturing technology and the three most widely used cellulosic biomass currently in the industry, wheat straw, corn stover, and switchgrass, will be used in the research. Experimental investigations on both lab and pilot scale biofuel conversion facilities will be conducted to test the hypotheses. Additionally, structural features, morphological changes, and chemical compositions of cellulosic biomass will be characterized by using electron microscopy, x-ray diffraction analysis, UV spectrophotometry, high performance liquid chromatography, IR spectroscopy, Simon's stain, and nuclear magnetic resonance techniques. Based on the experimental results, a sugar yield model, incorporating all the significant structural, morphological, and chemical features, will be developed and validated. The outcome of this research will provide insights in the dynamic degradation of sugar compounds during hydrolysis. It will advance the knowledge base needed to make both strategic and operational decisions in biofuel manufacturing.