UNS: Establishing Elementary Mechanisms of Biomass and Hemicellulose Torrefaction

PI: Phillip R. westmolands提案号：1512401将木质生物质运输到中央处理设施转化为有用的液体燃料是昂贵的，特别是在人口稀少的农村地区。烘烤是将植物生物量的重量和体积降低到更容易运输的形式的过程。在焙烧中，收获的生物质在没有空气的情况下在200至300摄氏度下加热，以产生致密的富含生物油的原料。然而，这种材料并没有很好地表征，并且含有气体、液体和固体形式的各种化合物。该项目将利用详细的反应过程知识，为生物质焙烧建立一个全面的数学模型，预测能源需求和最终产品混合物。然后，这个模型将用于开发可定制的热解过程，以从木质生物质中制造能量密度高、低氧的材料。研究结果将用于为本科生和研究生的工程课程提供示例，并通过高中教师的参与研究，使高中生能够开发生物燃料主题的课堂材料。本研究的目的是建立木质生物质半纤维素组分热解过程中的基本反应和动力学的综合模型。在热解过程中，生物质在200至300摄氏度的惰性气氛中加热。据推测，可以准确描述纤维素热解的周环反应也可以描述半纤维素的热解过程。该模型将利用反应动力学实验、计算量子化学和反应理论进行开发。热重分析将提供瞬时热裂解。产品气体和蒸汽将通过二维气相色谱飞行时间质谱（GCxGC-TOFMS）进行实时分析。这些实验将使用木质生物质（火炬松）、半纤维素生物聚合物木聚糖和半乳糖葡甘露聚糖、半纤维素单体木糖、阿拉伯糖、甘露糖和半乳糖等固体样品进行。通过在线GCxGC-TOFMS对生物油产品蒸气进行分析，并辅以固态核磁共振（NMR）对残余固体结构进行分析，研究了固化固体的闪蒸热解反应过程。单体反应的量子化学分析将有望产生额外的机理见解。完整的模型将预测木质生物质中纤维素和半纤维素组分的反应动力学和焙烧产物。基于该研究的教育活动包括指导一个本科过程设计团队设计一个热化学生物质处理厂，为本科和研究生阶段的反应动力学和运输课程编写课程材料，以及为本科生和高中教师提供研究经验。

PI: Phillip R. WestmorelandProposal Number: 1512401The transportation of woody biomass to a central processing facility for conversion into useful liquid fuels can be costly, particularly in sparsely populated rural areas. Torrefaction is process that reduces the weight and volume of plant biomass to a form which can be transported more easily. In torrefaction, harvested biomass is heated in the absence of air at 200 to 300 degrees Celsius to create a dense bio-oil rich feedstock. However, this material is not very well characterized and contains a wide variety of compounds in gas, liquid, and solid forms. This project will develop a comprehensive mathematical model for the torrefaction of biomass that will predict the energy requirements and final product mixture, using knowledge of the detailed reaction processes. This model will then be used to develop torrefaction processes that can be tailored to make an energy-dense, low-oxygen material from woody biomass. Research results will be used to provide examples in engineering classes at undergraduate and graduate levels, and to enable the development of classroom materials on biofuel topics for high school students through the involvement of high school teachers in research.The goal of this research is to develop a comprehensive model for the elementary reactions and kinetics during the torrefaction of the hemicellulose fraction of woody biomass. In torrefaction, the biomass is heated in an inert atmosphere at 200 to 300 degrees C. It is hypothesized that pericyclic reactions, which are known to describe cellulose pyrolysis accurately, also describe the torrefaction of hemicellulose. The model will be developed using reaction kinetics experiments, computational quantum chemistry, and reaction theory. Thermogravimetric analyses will provide instantaneous heats of pyrolysis. Product gases and vapors will be profiled in real time by two-dimensional gas chromatography with time-of-flight mass spectrometry (GCxGC-TOFMS). These experiments will be carried out with solid samples of woody biomass (loblolly pine), the hemicellulose biopolymers xylan and galactoglucomannan, and hemicellulose monomers xylose, arabinose, mannose, and galactose. The reaction processes for the flash pyrolysis of the torrefied solids will be studied by online GCxGC-TOFMS analysis of the bio-oil product vapors, complimented by analysis of the residual solid structures using solid-state nuclear magnetic resonance (NMR). Quantum-chemistry analyses of monomer torrefaction will be expected to yield additional mechanistic insights. The full model will predict reaction kinetics and products of the torrefaction of cellulose and hemicellulose fractions of woody biomass. Educational activities based on the research include mentoring of an undergraduate process design team on the design of a thermochemical biomass processing plant, development of course materials for reaction kinetics and transport courses at the undergraduate and graduate levels, and research experiences for undergraduates and high school teachers.