The effect of droplet size and powder particle size on the mechanisms of nucleation and growth in fluid bed melt agglomeration
The effect of droplet size and powder particle size on the mechanisms of nucleation and growth in fluid bed melt agglomeration
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DOI：
10.1016/s0378-5173(02)00530-6
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发表时间：
2002-12-05
影响因子：
5.8
通讯作者：
Schæfer, T
中科院分区：
文献类型：
--
作者：
Abberger, T;Seo, A;Schæfer, T
进行本研究的目的是评估粘合剂液滴尺寸和粉末粒径对使用可熔粘合剂的流化床喷雾团聚中团聚物形成和生长的影响。使用两种不同浓度（11.5 或 22%（体积/质量））的聚乙二醇 (PEG) 3000 将三种不同的乳糖等级（100、125 或 350 目）聚集在一起，并使用三种喷雾液滴尺寸（30、60 或 90 μm）。发现液滴尺寸/颗粒尺寸的比率来确定成核机制是分布还是浸没。低比率促进分布，而高比率促进沉浸。作为成核机制的分布导致更开放的团聚结构和浸入更致密的结构。当成核阶段终止时，再润湿核或附聚物之间的聚结是与前述两种成核机制一起的生长机制。较大的乳糖颗粒尺寸导致较大的附聚物。 30 和 60 mum 液滴对生长的影响差异通常很小。粘合剂浓度为 22% 的 90 pm 液滴有可能出现无法控制的生长，从而导致明显更大的团聚体，且重现性低于 30 和 60 mum 液滴。 (C) 2002 Elsevier Science B.V. 保留所有权利。
This study was performed in order to evaluate the effects of binder droplet size and powder particle size on agglomerate formation and growth in fluid bed spray agglomeration using a meltable binder. Three different lactose grades, 100, 125 or 350 mesh, were agglomerated using polyethylene glycol (PEG) 3000 at two different concentrations, 11.5 or 22% (volume/mass), and three spray droplet sizes, 30, 60 or 90 mum were applied. The ratio of droplet size/particle size was found to determine whether the mechanism of nucleation was distribution or immersion. Distribution was promoted by a low ratio, whereas immersion was promoted by a high ratio. Distribution as nucleation mechanism led to a more open agglomerate structure and immersion to a denser structure. When the nucleation phase was terminated, coalescence between rewetted nuclei or agglomerates was the growth mechanism with both preceding mechanisms of nucleation. A larger particle size of the lactose led to larger agglomerates. The difference in the effect on growth between the 30 and 60 mum droplets was generally low. The 90 pm droplets at 22% binder concentration offered a potential for uncontrollable growth giving rise to markedly larger agglomerates and a lower reproducibility than 30 and 60 mum droplets. (C) 2002 Elsevier Science B.V. All rights reserved.