Fluidised bed agglomeration of particles with different glass transition temperatures
Fluidised bed agglomeration of particles with different glass transition temperatures
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DOI：
10.1016/j.powtec.2014.03.026
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发表时间：
2015-01-01
影响因子：
5.2
通讯作者：
Turchiuli, Christelle
中科院分区：
文献类型：
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作者：
Aviles-Aviles, Carlos;Dumoulin, Elisabeth;Turchiuli, Christelle
颗粒的流化床附聚包括在颗粒表面喷射液滴（水或粘合剂溶液），通过热空气流化，以产生粘性区域，从而在粘性颗粒碰撞时形成附聚物。许多参数影响团聚生长，特别是那些控制颗粒循环的参数，以及床内的水和温度条件，这些条件决定干燥和颗粒粘性，这些粘性与无定形组分的玻璃化转变和颗粒表面潮湿区域的粘度有关。具有不同玻璃化转变温度范围的麦芽糖糊精 DE12 和 DE21 颗粒在批量实验规模流化床中团聚，在恒定的机械约束下，改变喷水进料速率和流化空气温度，以研究颗粒粘性对团聚体生长的影响。附聚物生长动力学和机制。两种粉末对所施加的水和温度限制表现出不同的敏感性。对于麦芽糖糊精 DE12，尺寸和生长速率随着喷射水流量的增加而显着增加，而对于麦芽糖糊精 DE21 只观察到很小的变化。在这两种情况下，附聚发生在两个阶段：首先，初始颗粒的缔合，其次中间附聚物附聚成更大且更多孔的结构。从一种增长机制到另一种增长机制的变化取决于条件，并影响团聚体的尺寸分布和结构。 (C) 2014 Elsevier B.V. 保留所有权利。
Fluidised bed agglomeration of particles consists in spraying liquid drops (water or binder solution) on the surface of particles, fluidised by hot air, in order to create sticky regions to allow formation of agglomerates when the sticky particles collide. Many parameters influence agglomerate growth, especially those controlling the particle circulation, and the water and temperature conditions within the bed that determine drying and particle stickiness linked to the glass transition of amorphous components and to the viscosity of moist zones at the particle surface.Maltodextrin DE12 and DE21 particles with different glass transition temperature domains were agglomerated in a batch bench scale fluidised bed, under constant mechanical constraints, changing the sprayed water feed rate and the fluidisation air temperature in order to investigate the influence of particle stickiness on agglomerate growth kinetics and mechanism.The two powders showed a different sensitivity to the water and temperature constraints applied. Whilst for maltodextrin DE12, the size and growth rate increased significantly with the sprayed water flow rate, only a small variation was observed for maltodextrin DE21. In both cases, agglomeration occurred in two stages: firstly, the association of initial particles and secondly the agglomeration of intermediate agglomerates into larger and more porous structures. The change from one growth mechanism to the other depended on the conditions, and influenced the size distribution and structure of agglomerates. (C) 2014 Elsevier B.V. All rights reserved.