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

0966419Garcia-Perez 虽然生物质快速热解然后对所得生物油进行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较低。提高纤维素热化学反应对左旋葡聚糖和纤维二聚糖生产的选择性对于提高该技术的整体效率至关重要。获得的初步数据表明，通过预处理（形成活性纤维素）结合更好地控制热解条件（降低热解温度和添加少量酸）来改变纤维素结构可能是提高左旋葡聚糖生产选择性的有效方法。这种方法的主要缺点是，如果预处理控制不好，可能会发生导致木炭形成的不良交联反应。此外，木质素的存在似乎抑制了形成脱水糖的解聚反应。文献中报道的先前研究表明，如果向热解反应器中添加少量酸，则可以减轻木质素的抑制作用。因此，该项目的主要目标是加深对预处理过程中发生的反应（活性纤维素形成和交联）以及快速热解过程中发生的反应（活性纤维素形成、交联、解聚和破碎）动力学的理解，并确定预处理和快速热解条件的最佳组合，从而最大限度地提高左旋葡聚糖和纤维二聚糖的产量。该项目将分两个阶段进行。第一阶段将包括基础研究，以确定活性纤维素形成和交联的动力学。动力学研究将在丝网反应器中进行。将提出一个描述预处理反应器行为的数学模型，并在华盛顿州立大学的连续螺旋钻反应器中进行验证。在第二阶段，将获得碎裂和解聚反应的动力学，并且这些动力学方程将用于获得最佳的预处理和热解条件，以最大化左旋葡聚糖和纤维二聚糖的产量。 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，所得油将得到充分表征。这项研究工作将推进设计新预处理和热解技术所需的科学，以提高木质纤维素材料脱水糖的产量。该项目负责人正在华盛顿州立大学建立一个集研究和教育于一体的生物质热化学转化项目。现开设“生物质热化学转化技术”新课程。本文计划的新装置将用于本课程，并将可供其他研究小组使用。华盛顿州立大学为高中生推出了一项名为“想象明天”的新计划 (http://imagine.wsu.edu/)。该项目将为本次竞赛的一些获奖者提供奖学金，让他们在 2010 年、2011 年和 2012 年夏季在 PI 实验室工作。将为参加 WSU 夏令营的高中生准备一个生物燃料生产研讨会。除了在同行评审期刊和会议论文集上发表研究成果外，研究结果还将通过华盛顿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/).