Étude critique de quelques techniques expérimentales d’évaluation de la coulabilité des poudres

Abstract : In industrial sectors, such as chemical, pharmaceutical or food industries, poor flowability of powders is often the causes of process malfunction. Poor flowability can lead to the blocking of powders in a silo, dosing and filling problems, or even bad quality on final product. To ensure proper process operation, it is therefore necessary and essential to evaluate the flowability of powders used. For this purpose, several experimental techniques such as angle of repose devices, shear cells or powder packing devices can be used. Flowability indices can then be defined in order to classify the powders according to the flow quality. Experimental tests have been carried out on several types of powders and the first results have shown that the transition from one technique to another can modify or even reverse the classification of the powder flowability. Indeed, according to the techniques studied, powders are subjected to different mechanical stresses and therefore the choice of the technique must be adapted to the real case of study. In this work, we were particularly interested to the evaluation of powders flowability from compaction devices. The work carried out has shown that the dynamic parameters (amplitude and frequency of taps) greatly influence the classification of powders flowability. From an energy approach, it has been shown that the evaluation of the flowability from Hausner ratio can be given by a compaction technique only if it achieves a value of energy required to obtain a maximal compaction of the particles. Finally, an implementation study of flowability evaluation techniques was carried out in the field of formulation by focusing on the quantitative evaluation of the influence of a glidant
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Theses
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http://docnum.univ-lorraine.fr/ulprive/DDOC_T_2018_0314_SAKER.pdf
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https://hal.univ-lorraine.fr/tel-02130382
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Submitted on : Wednesday, May 15, 2019 - 5:28:34 PM
Last modification on : Friday, May 17, 2019 - 9:28:19 AM

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Assia Saker. Étude critique de quelques techniques expérimentales d’évaluation de la coulabilité des poudres. Génie des procédés. Université de Lorraine, 2018. Français. ⟨NNT : 2018LORR0314⟩. ⟨tel-02130382⟩

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