Abstract Particle agglomeration in fluidized bed systems has been observed in several industrial processes. Bed particles tend to agglomerate when the cohesive force between the particles is strong enough to compare with the other acting forces (gravitational, drag). This cohesive force may arise because of different types of interactions: van der Waals, electrostatic, capillary, viscous, sintering, adhesive, chemical reaction, and so on. The most extensively reported case in the literature is concerned with the fluidized bed combustion of biomass, waste or low-rank coals, containing significant amounts of low-melting compounds (typically alkali metals) in the ash. The occurrence of bed agglomeration in such systems implies the unscheduled shut down of the reactor and costly maintenance operations. Therefore, a great deal of research has been devoted to understand and characterize agglomeration during fluidized bed combustion. This short review is focused on this specific system and tries to summarize the present status of understanding of the mechanisms leading to agglomeration, as well as the influence of the different operating variables on this phenomenon. In addition, because of their great practical importance, the possible early detection techniques and operational countermeasures are also briefly described.

中文翻译：

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流化床燃烧过程中的颗粒团聚：机理、早期检测和可能的对策

摘要 在几个工业过程中已经观察到流化床系统中的颗粒团聚。当颗粒之间的内聚力足够强以与其他作用力（重力、阻力）相比时，床颗粒趋向于团聚。这种内聚力可能由于不同类型的相互作用而产生：范德华力、静电、毛细管、粘性、烧结、粘合、化学反应等。文献中报道最广泛的案例涉及生物质、废物或低阶煤的流化床燃烧，灰中含有大量低熔点化合物（通常为碱金属）。在这种系统中发生床团聚意味着反应器的计划外关闭和昂贵的维护操作。所以，大量研究致力于了解和表征流化床燃烧过程中的团聚。这篇简短的评论集中在这个特定的系统上，并试图总结对导致集聚的机制的理解现状，以及不同操作变量对这种现象的影响。此外，由于它们具有重要的实际意义，还简要描述了可能的早期检测技术和作战对策。