Chemical Looping Beyond Combustion: Syngas Production From Methane in a Periodically Operated Fixed-Bed Reactor

智能优点：周期性操作的固定床反应器是一种新兴的催化反应器，在能源和环境应用中的应用越来越多。本项目旨在展示一种新兴的燃烧技术--化学环流在固定床固定床周期运行的反应器中将甲烷部分氧化为合成气的应用。由此产生的工艺具有显著的实用优势(通过避免甲烷和氧气之间的直接接触缓解了对甲烷部分氧化的安全担忧，并允许在不用氮气稀释合成气的情况下直接利用空气)，同时将允许研究周期性固定床反应器中吸热/放热的气固耦合反应的动力学。项目组将进一步将化学循环原理扩展到全多功能反应堆设计上，通过整合产品流的脱硫，产生一个强大的强化、高度可扩展和高效的合成气体过程。该方法建立在材料合成、反应堆设计和实验以及反应器建模的组合之上，具体涉及以下步骤：-设计和建造具有高分辨率动力学和时空反应器动力学原位测量的固定床反应器；-合成、表征和评估作为氧载体和部分氧化催化剂的高性能纳米结构材料；-详细的反应堆试验，包括评估关键的反应堆运行参数(顺流和逆流流型、周期性等)总而言之，本研究的主要目的是：(1)通过实验和反应器建模的结合，加深我们对具有热集成(特别是气固反应)的周期性操作的固定床反应器的动力学的理解；(2)展示燃烧以外的化学循环(CL)的巨大潜力(包括集成污染物分离)，并进一步确立固定床CL过程的优势；以及(3)突出最先进的纳米材料作为促进剂的激动人心的可能性。对于先进的反应堆工程概念，该项目将增进我们对固定床反应器定期运行的知识和当前的理解，特别是对于气固反应，这一领域的重要性远远超过化学环流。它还将进一步强调新兴纳米材料在实现先进反应堆概念方面可以发挥的促进作用。最后，有助于进一步建立和拓展化学环。通过演示同时使用化学循环进行部分氧化反应和污染物去除，并通过彻底的实验和基于模型的分析，为将这一概念扩展到广泛的新应用奠定了基础。广泛影响：在美国已探明的国内天然气储量爆炸性增长之际，展示用于天然气利用的新型、紧凑、高效和安全的反应堆概念可能会产生广泛的影响。此外，这项技术可以利用垃圾填埋气和农业废气等小规模的分布式来源，从而产生切实的环境效益。该项目将有助于研究生和本科生的教育，并涉及到对来自代表性不足群体的高中生的宣传。最后，通过合作、出版物和会议稿件积极分发已开发的方法和工具，将有助于促进伙伴关系，并向整个科学界提供进展。

Intellectual Merit: Periodically operated fixed-bed reactors are an emerging type of catalytic reactors with increasing application in energy and environmental applications. The present project aims to demonstrate the application of chemical looping, an emerging combustion technology, to the partial oxidation of methane to synthesis gas in a periodically operated fixed-bed reactor configuration. The resulting process has significant practical advantages (alleviating safety concerns in methane partial oxidation by avoiding direct contact between methane and oxygen, and allowing direct utilization of air without diluting the syngas with nitrogen), and will at the same time allow the investigation of the dynamics of coupled endothermal/exothermal gas-solid reactions in periodic fixed-bed reactors. The project team will furthermore extend the chemical looping principle onto a fully multifunctional reactor design by integrating desulfurization of the product stream, resulting in a strongly intensified, highly scalable, and efficient syngas process.The approach builds on a combination of materials synthesis, reactor design and experimentation, and reactor modeling, and involves specifically the following steps:- Design and construction of a fixed-bed reactor with high-resolution in-situ measurement of kinetics and spatio-temporal reactor dynamics;- Synthesis, characterization, and evaluation of high-performance nanostructured materials as oxygen carriers and partial oxidation catalysts;- Detailed reactor experimentation, including evaluation of key reactor operating parameters (co- and counter-current flow pattern, periodicity, etc.) on reactor dynamics and process efficiency;- Integration of S-capture and separation, and- Reactor modeling and detailed reactor simulation.Overall, the main objectives of this research are (1) to advance our understanding of the dynamics of periodically operated fixed-bed reactors with heat-integration (specifically for gas-solid reactions) through a combination of experiments and reactor modeling; (2) to demonstrate the great potential of chemical looping (CL) beyond combustion (including integrated contaminant separation) and further establish the advantages of fixed-bed CL processes; and (3) to highlight the exciting possibilities of state-of-the-art nanomaterials as ?enablers? for advanced reactor engineering concepts .The project will advance our knowledge and current understanding of periodically operated of fixed-bed reactors, specifically for gas-solid reactions, an area with importance well beyond chemical looping. It will furthermore highlight the enabling role that emerging nanomaterials can play in the realization of advanced reactor concepts. Finally, it will help to further establish and broaden ?chemical looping? applications by demonstrating the simultaneous use of chemical looping for a partial oxidation reaction combined with contaminants removal, and, through thorough experimental and model based analysis, lay the groundwork for extending the concept onto a broad range of new applications.Broader Impact: Demonstration of a novel, compact, efficient, and safe reactor concept for natural gas utilization could have broad impact at a time where proven domestic gas reserves in the US are seeing explosive growth. Furthermore, this technology could enable the use of small-scale distributed sources, such as landfill gas and agricultural waste gas, resulting in tangible environmental benefits. The project will contribute to the education of graduate and undergraduate students, and involve outreach to high school students from underrepresented groups. Finally, active distribution of the developed methodologies and tools through collaborations, publications and conference contributions will help to foster partnerships and make the advances available to the scientific community at large.