Abstract This study elucidates the sequential progression of agglomerate growth in fluidized beds through an investigation of physics and chemistry of particle-particle interaction. In fluidized bed gasification and combustion systems, agglomeration occurs by sticking of ash particles that are wetted by slag-liquid. Penn State has developed an agglomeration modeling methodology that considers non-uniform temperature, gaseous atmosphere and heterogeneity in ash chemical composition to predict slag-liquid formation and agglomerate growth rate. Simulations performed on three high rank coals with a consideration of these heterogeneous conditions, along with a microscopic (SEM) particle-level analysis of agglomerates facilitated an understanding of steps involved in their formation. The results of this study indicated that agglomerate growth in fluidized bed systems is initiated at the particle-level by low-melting components rich in iron- and calcium-based minerals. Agglomeration can begin at lower temperatures than the fluidized bed operating temperatures of 850 °C and the severity of agglomerate growth issues can be identified based on the slag-liquid level in the system. Understanding the stages involved in the process of agglomerate growth discussed in this paper can help develop early detection methods and mitigation strategies.

中文翻译：

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使用实验室生成的附聚物的模拟和 SEM-EDX 表征研究流化床附聚物的生长过程

摘要 本研究通过对粒子-粒子相互作用的物理和化学研究，阐明了流化床中团聚体生长的连续过程。在流化床气化和燃烧系统中，结块是由被渣液润湿的灰颗粒粘附而发生的。Penn State 开发了一种团聚建模方法，该方法考虑了不均匀的温度、气体气氛和灰分化学成分的异质性，以预测渣液形成和团聚体生长速率。考虑到这些非均质条件对三种高阶煤进行的模拟，以及对团聚体的微观 (SEM) 颗粒级分析，促进了对其形成过程的理解。这项研究的结果表明，流化床系统中的附聚物生长是由富含铁和钙基矿物质的低熔点成分在颗粒水平引发的。结块可以在比 850 °C 的流化床操作温度更低的温度下开始，结块生长问题的严重程度可以根据系统中的渣液水平来确定。了解本文中讨论的聚集增长过程中涉及的阶段，有助于制定早期检测方法和缓解策略。结块可以在比 850 °C 的流化床操作温度更低的温度下开始，结块生长问题的严重程度可以根据系统中的渣液水平来确定。了解本文中讨论的聚集增长过程中涉及的阶段，有助于制定早期检测方法和缓解策略。结块可以在比 850 °C 的流化床操作温度更低的温度下开始，结块生长问题的严重程度可以根据系统中的渣液水平来确定。了解本文中讨论的聚集增长过程中涉及的阶段，有助于制定早期检测方法和缓解策略。