CAREER: Revealing Kinetic Pathways by Pulsed-Film Pyrolysis of Cellulosic Biomass

通过燃烧、热解或气化将木质纤维素、非食用生物质转化为生产第二代生物燃料提供了一套可持续的技术，这些技术可以对能源独立、经济增长、全球排放和我们的社会产生重大影响。然而，尽管在过去的几十年里进行了大量的研究，但仍然缺乏与这些体系相关的基础知识，包括反应途径、中间体和详细的动力学。正是这种信息导致了炼油业在过去一个世纪的成功发展，也是生物质利用的迫切需要。对这些转化技术缺乏基本了解的部分原因是原料的多相和多尺度性质，以及与传输效应交织在一起的大型反应网络的复杂性。智力优势：我们的研究目标是通过开发和利用一种被称为脉冲薄膜热解的新实验技术，首次对纤维素热解的单个分子反应进行动力学描述。或者亲民党。建议的PFP技术旨在将微米级的纤维素膜快速加热到400-600°C，然后在一定的时间增量(例如10ms)内进行等温热解，然后快速热淬火。然后，将通过表征每个连续热脉冲产生的化学物种的数量和类型来获得关于反应速度的动力学信息。研究计划1。)开发脉冲膜热解技术：三项任务将集中在设计、建造和测试用于纤维素热解的脉冲膜技术。利用多物理设计模型和新颖的反应堆结构将使第一个能够在高温下进行免运输动力学实验的实验系统成为可能。分为两个具体目标：1.)测量纤维素热解的动力学：三项任务将测量初级产物(如左旋葡聚糖和呋喃)的形成速度、左旋葡聚糖的二次反应以及将纤维素还原为反应性低聚物的缩合相反应。在完成这两个目标后，预计将首次测量纤维素热解的主要途径的动力学。学术价值：拟议的研究将改变我们对固体和凝聚相生物质化学的反应机理和动力学的理解。这项研究的一个引人注目的方面是，它提供了第一个在实验上测量与关键热解产物形成相关的活化能的策略，可以与正在进行的计算相比较，首次阐明生物质热解的机理。广泛的影响：生物质反应路径和动力学的科学发现将为构建第一性原理动力学模型提供关键数据，该模型可用于热解反应器的优化。改进的生物质过程通过以更低的成本生产更高质量的生物燃料并减少对环境的影响而广泛影响该国。此外，拟议中的生物质热解研究的发现和基本见解将为开发具有教育意义的材料提供大量机会，以教育潜在的本科生、高中生和普通公众关于生物质转化为燃料和化学品的价值和环境影响。我们建议制定一项具有广泛影响的综合战略，将高中教师的教育与本科生的指导结合起来，为围绕生物质技术、环境影响和政策主题的公共研讨会制定演讲。已经提出了一项每年举办公共研讨会的发展计划，该计划将与教育材料一起在互联网上播出，以便广泛传播。与研讨会整合的将是一门以可再生能源为重点的本科课程，以及一项NSF-RET建议，在少数民族人数较少的学校(马萨诸塞州斯普林菲尔德和威斯康星州密尔沃基)接待科学教师并为K-12学生开发学习模块。我们的教育方法将有助于确保来自经济不景气背景和代表性不足的少数群体的学生能够获得工程科学和技术的鼓舞人心的例子，并确保公众充分了解生物质转化的重要性，这是实现国家独立于进口石油目标的一种可持续和环境友好的手段。

The conversion of lignocellulosic, non-food biomass by combustion, pyrolysis, or gasification provides a sustainable set of technologies for the production of second generation biofuels that can have significant impact on energy independence, economic growth, global emissions, and our society. However, despite intensive research for the past several decades, there is still a lack of fundamental knowledge pertaining to these systems including reaction pathways, intermediates, and detailed kinetics. It is this kind of information that has led to the successful development of the refinery industry in the past century and which is critically needed for biomass utilization. The lack of progress on fundamental understanding of these conversion technologies is partially rooted in the multiphase and multi-scale nature of the raw material and the associated complexity of a large reaction network convoluted with transport effects.Intellectual Merit: Our objective in this research is to develop the first kinetic description of the individual molecular reactions of cellulose pyrolysis by developing and utilizing a novel experimental technique referred to as ?pulsed-film pyrolysis,? or PFP. The proposed PFP technique aims to rapidly heat micro-scale films of cellulose to 400-600 °C, whereupon isothermal pyrolysis occurs for a defined increment of time (e.g. 10 ms), followed by rapid thermal quench. Kinetic information on the rate of reaction will then be obtained from characterizing the quantity and type of chemical species produced for each consecutive thermal pulse. The research plan1.) Develop the technique of pulsed-film pyrolysis: Three tasks will focus on designing, constructing, and testing the pulsed-film technique for cellulose pyrolysis. Utilization of multi-physics design models and novel reactor construction will allow for the first experimental system capable of transport-free kinetic experiments at high temperature. is divided into two specific aims:2.) Measure the kinetics of cellulose pyrolysis: Three tasks will measure rates of formation of primary products (e.g. levoglucosan and furans), secondary reactions of levoglucosan, and condensed-phase reactions to reduce cellulose to reactive oligomers.At the completion of these two aims, it is anticipated that the kinetics of the major pathways of cellulose pyrolysis will be measured for the first time. Intellectual merit: The proposed research will transformour understanding of the reaction mechanisms and kinetics of solid and condensed-phase biomass chemistry. A compelling aspect of this research is that it provides the first strategy for experimentally measuring the activation energies associated with the formation of key pyrolysis products, which can be compared with ongoing computations to elucidate for the first time the mechanisms of biomass pyrolysis.Broader Impact: The scientific discoveries of biomass reaction pathways and kinetics will provide the critical data for constructing first-principles kinetic models which can be used to optimize pyrolysis reactors. Improved biomass processes broadly impact the country by producing higher quality biofuels with lower cost and reduced environmental impact. Additionally, the discoveries and fundamental insights from the proposed research on the pyrolysis of biomass will provide a plethora of opportunities for developing instructive material to educate prospective undergraduates, high school students and the general public on the value and environmental impact of biomass conversion to fuels and chemicals. We propose to develop an integrated strategy with broad impact which combines the education of high school teachers and the instruction of undergraduates to develop presentations for public symposia on the topic of biomass technology, environmental impact and policy. A year-to-year development plan has been proposed for conducting public symposia, which will be broadcast on the internet along with educational materials for broad dissemination. Integrated with the symposia will be an undergraduate course focused on renewable energy as well as an NSF-RET proposal for hosting science teachers and developing learning modules for K-12 students in schools with high concentration of underrepresented minorities (Springfield, MA, & Milwaukee, WI). Our approach to education will contribute to ensuring that students from economically depressed backgrounds and underrepresented minorities have access to inspiring examples of engineering science and technology and that the general public is well-informed on the importance of biomass conversion as a sustainable and environmentally-friendly means of achieving the national goal of independence from imported oil.