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Title: Production of catalyst supports by twin screw extrusion of pastes
Author: Winstone, Gemma
Awarding Body: University of Birmingham
Current Institution: University of Birmingham
Date of Award: 2011
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The production of ceramic catalyst supports is commonly performed by the extrusion of a paste. The rheological properties of the paste as it passes through the extruder have a strong influence on the extrudate properties such as porosity and strength, which in turn affect the catalytic performance of the final product. An assessment of the effect of acid type and strength and powder type on the rheological properties of concentrated boehmite slurries has been made. In particular, evidence of gel formation is looked for, and the surface chemistry is examined using zeta potential measurements. Further understanding of the observed rheological changes is obtained by performing nuclear magnetic resonance studies and cryogenic microscopy. The effect of powder properties and acid type and strength on the saturation states of a formulation has been examined using mixer torque rheometry. The prediction of saturation states from bulk density measurements is discussed. The predictive capability of the mixer torque rheometer with regards extrusion formulations is investigated. The effect of acid type and strength on successful extrusion formulations and extrudate properties is discussed.
Supervisor: Not available Sponsor: Johnson Matthey
Qualification Name: Thesis (D.Eng.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: TP Chemical technology