Coal combustion-generated aerosols: Formation and properties
Coal combustion-generated aerosols: Formation and properties
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DOI：
10.1016/j.proci.2010.09.014
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
Minghou Xu;Dunxi Yu;H. Yao;Xiaowei Liu;Y. Qiao
中科院分区：
文献类型：
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作者：
Minghou Xu;Dunxi Yu;H. Yao;Xiaowei Liu;Y. Qiao
燃煤发电是颗粒物空气污染的主要来源。了解燃煤气溶胶的形成机制和特性对于颗粒物控制技术的发展和评估其对人类健康的影响至关重要。本文概述了目前对煤粉燃烧、流化床燃烧和煤气化等主要煤基发电过程中灰颗粒形成机制的认识，并总结了对于阐明颗粒形成和评估其健康影响非常重要的气溶胶特性。回顾了主要颗粒形成机制，包括矿物聚结、颗粒破碎和汽化冷凝。强调了亚微米气溶胶形成机制的复杂性。一些固体到颗粒的过程被怀疑有助于亚微米气溶胶的形成，提供了证据。讨论了物理化学性质，例如粒径、组成和形态。特别令人感兴趣的是灰气溶胶尺寸分布的三峰性。尺寸解析的元素组成数据用于识别粒子模式并揭示其形成机制。附加中心颗粒模式的形成归因于汽化物质在现有细小的残留灰分颗粒上的异质凝结。讨论了与灰气溶胶形成和特性相关的未来研究主题。
Coal combustion for power generation is a major source of particulate air pollution. Understanding of the formation mechanisms and properties of coal combustion aerosols is critical to both the development of particulate control technologies and the assessment of their impacts on human health. This paper presents an overview of the current understanding of the mechanisms of ash particle formation in major coal-based power generation processes such as pulverized coal combustion, fluidized bed combustion and coal gasification, and a summary of the aerosol properties that are important for elucidating particle formation and evaluating their health effects. Principal particle formation mechanisms, including mineral coalescence, particle fragmentation, and vaporization-condensation, are reviewed. The complex nature of the formation mechanisms of submicron aerosols is emphasized. Evidence is provided for some solid-to-particle processes that are suspected to contribute to the formation of the submicron aerosols. Physicochemical properties such as particle size, composition and morphology are discussed. Of particular interest is the trimodality of the ash aerosol size distribution. Size-resolved elemental composition data are used to identify particle modes and to uncover their formation mechanisms. The formation of the additional central particle mode is attributed to heterogeneous condensation of vaporized species on existing fine residual ash particles. Future research topics associated with ash aerosol formation and properties are discussed.