Trace Metal Interactions with Fly Ash in Combustion Flue Gas

燃烧烟气中痕量金属与飞灰的相互作用

• 批准号: 1235878
• 负责人: Jennifer Wilcox
• 金额: $ 32.7万
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-15 至 2015-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1235878&HistoricalAwards=false
• 关键词: Trace; Metal; Interactions; Fly; Ash

Arsenic, mercury, and selenium exist as trace metals (TMs) in minerals and organic matter in coal and may be emitted to the environment during coal conversion processes. The ultimate goals of the proposed research efforts are to understand heterogeneous TM speciation on mineral surfaces in contact with flue gases as a function of the size and chemical phase of the fly ash particles, with broader impacts toward understanding their life cycle throughout the environment in addition to their potential toxicity. Foundational knowledge from catalysis, geochemistry, surface chemistry, and fuel combustion science will be compiled, applied, and advanced in the proposed work. The synergistic coupling of geological and fuel chemistry perspectives can be highlighted by considering the commonalities and differences of the TMs-interface systems relevant to both ground water and fuel exhaust systems. Geochemical studies of well-characterized single crystal surfaces of metal oxides will provide the required framework for understanding fuel combustion particle-bound TM emissions. In addition, the integration of experimental and theoretical approaches to the interaction of TMs with fly ash particles under a broad range of relevant conditions will result in new information on sequestration mechanisms and stability of reaction products.Intellectual Merit will be achieved since the proposed investigations will be the first of their kind focusing on high-level fly ash characterization and testing closely coupled with theoretical models to determine heterogeneous TM reactivity in simulated combustion flue gas. Additionally, the PIs are using a novel self-designed experimental technique based on mass spectrometry to directly speciate the various forms of TM in flue gas. In this way, both redox and sorption activity of the fly ash particles will be determined. The Broader Impacts of the proposed efforts are evident through the use of software packages based upon results of this work by major utility companies and technology developers worldwide to determine the most effective strategies of minimizing the release of toxic TMs into the atmosphere. Additionally, the PIs have direct links to industry through collaborations, which will facilitate summer internships for students involved in the research. Results of the proposed work will also provide indication of the TM life cycle once these species enter the environment.

砷、汞和硒以痕量金属(TM)的形式存在于煤中的矿物和有机物中，并可能在煤炭转化过程中排放到环境中。拟议研究工作的最终目标是了解与烟道气体接触的矿物表面上的非均质TM形态与飞灰颗粒的大小和化学相的函数关系，以及对了解其在整个环境中的生命周期以及其潜在毒性的更广泛影响。催化、地球化学、表面化学和燃料燃烧科学的基础知识将在拟议的工作中汇编、应用和推进。通过考虑与地下水和燃料排气系统相关的TMS界面系统的共性和差异，可以突出地质和燃料化学观点的协同耦合。对表征良好的金属氧化物单晶表面的地球化学研究将为理解燃料燃烧颗粒结合TM排放提供必要的框架。此外，在广泛的相关条件下，TMS与飞灰颗粒相互作用的实验方法和理论方法的结合将产生关于反应产物的隔离机理和稳定性的新信息。由于拟议的研究将首次专注于高水平的飞灰表征，并与理论模型紧密结合以确定模拟燃烧烟气中的非均相TM反应性，因此将获得智力上的好处。此外，PI正在使用一种基于质谱学的自行设计的新实验技术来直接确定烟气中TM的各种形式。通过这种方法，可以同时测定飞灰颗粒的氧化还原活性和吸附活性。拟议努力的更广泛影响是显而易见的，因为世界各地的主要公用事业公司和技术开发商根据这项工作的结果使用软件包，以确定最有效的战略，尽量减少向大气中排放有毒的TMS。此外，PI通过合作与行业有直接联系，这将为参与研究的学生提供暑期实习机会。一旦这些物种进入环境，拟议工作的结果还将提供TM生命周期的指示。