EAGER: Determining pyrolysis kinetics through time-resolved measurements of condensed phase reactions

1630404-布朗大学项目探索了生物质在缺氧条件下快速加热分解的化学过程，这一过程被称为快速热解，产生气体、液体和固体。 来自生物质的快速热解的液体显示出生产先进生物燃料和生物基化学品的前景，类似于从石油生产的传统汽油和柴油燃料。了解快速热解过程中发生的化学反应并测量它们的速率对于设计未来将生物质转化为燃料和化学品的生物精炼厂非常重要。该项目将探索新的实验技术，用于探测固体生物质在几秒钟内迅速加热到高温后发生的反应。通过跟踪各种分解产物的浓度随时间的变化，可以确定重要热解反应的速率。本研究的目的是通过对凝相反应的时间分辨测量来测量生物质快速热解的化学动力学。热解是大多数热化学过程的基础，包括燃烧，气化，快速热解，甚至溶剂液化。 在这些技术中，快速热解在过去几年中因其从木质纤维素生物质生产先进生物燃料和生物基化学品的前景而受到相当大的关注。 自20世纪50年代以来，已经研究了热解的反应机理，但是在确定与构成木质纤维素生物质的生物聚合物的解聚相关的基本反应速率方面仅取得了适度的进展。 如果没有这些反应的速率系数和活化能，很难从第一性原理准确地建模和设计热解反应器。 大多数以前的热解动力学的研究已经测量了经历相对缓慢的加热的样品的重量损失，这产生很少的信息发生在固体生物质中的基元反应。本研究将展示在爱荷华州州立大学开发的用于研究凝聚相基元化学反应的两个版本的受控热解持续时间（CPD）-淬火反应器的实用性。第一个，能够调查的反应，发生在几秒钟的顺序，将被用来研究解压缩的小寡糖，形成脱水单糖左旋葡聚糖。 第二，能够调查更快的反应，将被用来研究裂解纤维素低聚糖在解聚过程的早期。这些装置也将用于研究半纤维素和木质素的解聚。

1630404-BrownThis project explores the chemical processes responsible for the decomposition of biomass when it is rapidly heated in the absence of oxygen, a process known as fast pyrolysis, to produce gases, liquids, and solids. The liquids from fast pyrolysis from biomass show promise for the production of advanced biofuels and biobased chemicals that resemble conventional gasoline and diesel fuels produced from petroleum. Understanding the chemical reactions that occur during fast pyrolysis and measuring their rates are important for designing future biorefineries that would convert biomass into fuels and chemicals. This project will explore new experimental techniques for probing reactions that occur in solid biomass after it has been rapidly heated to high temperatures in a matter of seconds. By tracking the change in concentration of various decomposition products with time, rates of important pyrolysis reactions can be determined. The goal of this research is to measure the chemical kinetics of biomass fast pyrolysis through time-resolved measurements of condensed phase reactions. Pyrolysis is the basis for most thermochemical processes including combustion, gasification, fast pyrolysis, and even solvent liquefaction. Among these technologies, fast pyrolysis has gained considerable attention in the last few years for its prospects to produce advanced biofuels and biobased chemicals from lignocellulosic biomass. The reaction mechanisms of pyrolysis have been studied since the 1950s, but only modest progress has been made in determining elementary reaction rates associated with the depolymerization of the biopolymers that make up lignocellulosic biomass. Without rate coefficients and activation energies for these reactions, it is difficult to accurately model and design pyrolysis reactors from first principles. Most previous studies of pyrolysis kinetics have measured weight loss of samples undergoing relatively slow heating, which yields little information about elementary reactions occurring in solid biomass. This research will demonstrate the utility of two versions of Controlled Pyrolysis Duration (CPD) - Quench reactors developed at Iowa State University for studying condensed phase elementary chemical reactions. The first, capable of investigating reactions that occur on the order of a few seconds, will be used to study unzipping of small oligosaccharides to form the anhydro-monosaccharide levoglucosan. The second, capable of investigating much faster reactions, will be used to study cracking of cellulose to oligosaccharides early in the depolymerization process. These apparatus will also be employed to study depolymerization of hemicellulose and lignin.