Understanding Cellulose Primary Thermo-chemical Reactions to Enhance the Yields of Anhydro-saccharides from Fast Pyrolisis

虽然生物质快速热解和加氢处理是将木质素转化为绿色汽油的有效方法，但纤维素转化为有价值的产品的效率很低。提高纤维素热化学反应对生产左旋葡聚糖和纤维二聚糖的选择性是提高这项技术的整体效率的关键。初步数据表明，通过预处理(形成活性纤维素)改变纤维素结构，结合更好地控制热解条件(降低热解温度和添加少量酸)，是提高左旋葡聚糖生产选择性的有效途径。这种方法的主要缺点是，如果前处理控制得不好，可能会发生不希望发生的导致木炭形成的交联反应。此外，木质素的存在似乎抑制了导致无氢糖形成的解聚反应。以往文献报道的研究表明，在热解反应器中加入少量的酸可以减轻木质素的抑制作用。因此，本项目的主要目标是促进对预处理(活性纤维素形成和交联)和快速热解(活性纤维素形成、交联、解聚和裂解)过程中发生的反应动力学的了解，并确定预处理和快速热解条件的最佳组合，以最大限度地提高左旋葡聚糖和纤维二糖的产量。该项目将分两个阶段进行。第一阶段将包括基础研究，以建立活性纤维素形成和交联的动力学。动力学研究将在金属丝网反应器中进行。将提出一个描述预处理反应器行为的数学模型，并在威斯康星州立大学的连续螺旋反应器中进行验证。在第二阶段，将得到裂解反应的动力学方程，并利用这些动力学方程来获得最优的前处理和裂解条件，以最大限度地提高左旋葡聚糖和纤维二糖的产率。α-纤维素和木质素的混合物将在这些条件下进行预处理和热解，得到的油将得到充分的表征。这项研究工作将推动设计新的预处理和热解技术以提高木质纤维材料生产无氢糖所需的科学水平。该研究所正在威斯康星州立大学建立一个生物质热化学转化项目，该项目将研究和教育融为一体。现在开设了一门新的“生物质热化学转化技术”课程。此处计划的新安装将用于本课程，并可供其他研究小组使用。威斯康星州立大学为高中生发起了一项新的倡议，名为“想象明天”(http://imagine.wsu.edu/).这个项目将为这次竞赛的一些获胜者提供奖学金，让他们在2010、2011和2012年的夏天在PI的实验室工作。将为参加华盛顿州立大学夏令营的高中生准备一个关于生物燃料生产的讲习班。除了在同行评议的期刊和会议记录上公布研究结果外，研究结果还将通过休斯敦州立大学能源计划网站(http://www.energy.wsu.edu/).)向公众传播

0966419Garcia-PerezAlthough biomass fast pyrolysis followed by the hydrotreatment of resulting bio-oils is an efficient approach to convert lignin into green gasoline, the conversion efficiencies of cellulose to valuable products is low. Enhancing the selectivity of cellulose thermo-chemical reactions towards the production of levoglucosan and cellobiosan is critical to increasing the overall efficiency of this technology. The preliminary data obtained suggest that modifying cellulose structure through pre-treatment (formation of active cellulose) in conjunction with a better control of pyrolysis conditions (reduction of pyrolysis temperature and addition of small amount of acids) could be an effective way to enhance the selectivity towards the production of levoglucosan. The major drawback of this approach is that undesirable cross-linking reactions leading to the formation of charcoal might happen if pre-treatment is not well controlled. Furthermore, the presence of lignin seems to inhibit the depolymerization reactions responsible for the formation of anhydrosugars. Previous studies reported in the literature suggest that the inhibitory effect of lignin can be mitigated if small amounts of acids are added to the pyrolysis reactor. Thus the primary goal of this project is to advance understanding of the kinetics of reactions happening during pretreatment (active cellulose formation and cross linking) and of those happening during fast pyrolysis (active cellulose formation, cross linking, depolymerization and fragmentation) and to identify the optimal combination of pretreatment and fast pyrolysis conditions maximizing the yields of levoglucosan and cellobiosan. This project will be carried out in two stages. The first stage will consist of fundamental studies to establish the kinetics of active cellulose formation and cross linking. The kinetic studies will be carried out in a wire mesh reactor. A mathematical model to describe the behavior of pretreatment reactors will be proposed and validated in a continuous auger reactor available at WSU. In the second stage the kinetics of fragmentation and depolymerization reactions will be obtained and these kinetic equations will be used to obtain the optimal pretreatment and pyrolysis conditions to maximize the yield of levoglucosan and cellobiosan. Blends of á-cellulose and lignin will be pretreated and pyrolysed at these conditions and the resulting oils will be fully characterized. This research effort will advance the science required to design new pretreatment and pyrolysis technologies to enhance the production of anhydrosugars from lignocellulosic materials. The PI is building a program at WSU in biomass thermo-chemical conversion which integrates research and education. A new course in "biomass thermo-chemical conversion technologies" is now offered. The new installations planned herein will be used for this course and will be accessible to other research groups. WSU has launched a new initiative for high school students called "Imagine Tomorrow" (http://imagine.wsu.edu/). This project will offer scholarships to some of the winners of this competition to work in the PI's lab during the summers of 2010, 2011 and 2012. A workshop in bio-fuel production will be prepared for high school students attending WSU summer camps. In addition to publishing the outcome of the research in peer reviewed journals and conference proceedings, the results will be disseminated to the public through the WSU Energy Program website (http://www.energy.wsu.edu/).