UNS: Collaborative Research: Multiple-Scale Investigation of Chemical Looping with Oxygen Carrier Uncoupling

合作提案#1511818/PI：Tian，Hanjiang #1510900/ P.I.：Li，Fanxing这项研究预计将为解决燃煤二氧化碳捕获和封存（CCS）提供基础知识和科学基础，这是环境可持续性最关键的领域之一。在各种CCS技术中，CLOU是一种针对固体燃料燃烧优化的CLC方案（例如，煤炭）是最有前途的选择之一。通过能够在不同氧分压下释放和吸收氧气的金属氧化物基氧载体，CLOU通过循环反应将煤间接转化为分离的可封存的富含CO2和N2的烟道气。因此，固有地避免了与CO2分离相关的能量损失。与氧燃料燃烧相比，能量密集的低温氧分离被氧载体所实现的容易的氧转移所取代，从而显著提高了碳捕获效率。由于对煤与氧载体相互作用的机理缺乏科学的认识，目前这方面的研究大多采用试错法。这种效率低下的方法不仅在技术和经济上引入了潜在的不确定性，而且还限制了CLC的开发和实施的进展。这项研究是由迫切需要开发新的科学认识和创新的工具和方法来研究煤-氧载体相互作用和动力学，氧载体优化以及反应器和过程模拟。该研究将为CLOU从原子级到反应堆和工艺规模的发展奠定坚实的理论基础。这些基础研究也有望导致令人兴奋的发现新的催化系统和反应器的配置受益于其他研究领域，如新的计划，氧气生产，生物质燃烧，煤/生物质气化，和SOx/NOx排放控制。具有氧载体解偶联的化学链燃烧，也称为CLOU代表了一种独特的燃烧方案，它与传统的燃烧过程直接相关，但又明显不同。它允许高效的化石燃料燃烧，而CO2分离的能量损失最小。由六位美国/这个多学科的团队汇集了顶尖的化学工程师、热工程师、机械工程师和催化科学家，以回答燃烧动力学、表面反应、氧载体开发、热工程和反应器/过程建模中关键的、相互关联的科学问题，从原子水平到反应器和过程规模。从拟议的研究中获得的基本发现预计将大大加快CLOU的开发和部署，以实现高效的煤炭燃烧和综合的CO2捕集。基础研究主要集中在四个方面：1）金属氧化物辅助煤焦/挥发分氧化体系中晶格氧扩散、表面反应和气相燃烧动力学; 2）载氧体与煤灰和杂质的相互作用; 3）循环流化床CLC反应器中载氧体的稳定性及性能评价，这些合作赠款由NSF国际科学与工程部（伊势）的全球风险基金（GVF）和CBET/ENG燃烧与火灾和环境可持续性计划共同资助。

Collaborative Proposals#1511818 / P.I.: Tian, Hanjiang#1510900 / P.I.: Li, FanxingThis research is expected to provide fundamental knowledge and scientific foundation for addressing CO2 capture and sequestration (CCS) from coal combustion, one of the most crucial areas of environmental sustainability. Among various CCS technologies, CLOU, a CLC scheme optimized for solid-fuel combustion (e.g., coal), represents one of the most promising options. Enabled by metal-oxide-based oxygen carriers capable of oxygen release and uptake under varying oxygen partial pressures, CLOU indirectly converts coal into separate streams of sequestration-ready CO2- and N2-rich flue gas via cyclic reactions. Consequently, the energy penalty associated with CO2 separation is inherently avoided. Compared to oxy-fuel combustion, the energy-intensive cryogenic oxygen separation is replaced by facile oxygen transfer enabled by the oxygen carrier, leading to significant improvement of carbon-capture efficiency. To date, most research in this area follows a trial-and-error approach due to lack of scientific understanding on the mechanism of coal-oxygen carrier interaction. Such an inefficient approach not only introduces potential uncertainties in technology and economics, but it also limits the progress of the development and implementation of CLC. The research is driven by the urgent needs for developing new scientific understanding and innovative tools and methodologies to investigate coal-oxygen carrier interaction and kinetics, oxygen-carrier optimization, and reactor and process simulations. The research will establish a solid theoretical groundwork for CLOU development from atomic level to reactor and process scales. These fundamental studies also are expected to lead to exciting discovery of novel catalytic-system and reactor configurations benefiting other research areas such as novel schemes for oxygen production, biomass combustion, coal/biomass gasification, and SOx/NOx emission control. Chemical Looping Combustion with Oxygen Carrier Uncoupling, a.k.a. CLOU, represents a unique combustion scheme that is directly related yet notably different from conventional combustion processes. It allows efficient fossil fuel combustion with minimal energy penalty for CO2 separation. Initiated by six leading U.S./Chinese research groups in the areas of both conventional and Chemical Looping Combustion (CLC), this multidisciplinary team brings together top chemical engineers, thermal engineers, mechanical engineers, and catalysis scientists to answer critical, interrelated scientific questions in combustion kinetics, surface reactions, oxygen-carrier development, thermal engineering, and reactor/process modeling, spanning from atomic level to reactor and process scales. Fundamental findings obtained from the proposed research are expected to significantly accelerate the development and deployment of CLOU for efficient coal combustion with integrated CO2 capture. The fundamental research focuses on four aspects: 1) lattice oxygen diffusion, surface reaction, and gas-phase combustion kinetics in a metal-oxide-assisted char/volatile oxidation scheme; 2) oxygen-carrier interactions with coal ash and impurities; 3) oxygen-carrier stability and performance evaluation in circulating fluidized bed CLC reactors, and 4) reactor and process modeling.These collaborative grants are co-funded by the Global Venture Fund (GVF) of NSF's International Science and Engineering section (ISE) and the CBET/ENG Combustion and Fire and Environmental Sustainability programs.