Skip to Main content Skip to Navigation

Nouveau procédé de précipitation pour la synthèse d’alumine

Abstract : Control of catalyst supports porosity is an important challenge for the refining industry. The aim of this thesis is to develop a new precipitation process in order to obtain γ-alumina supports exhibiting new textural properties compared with those prepared by the conventional boehmite precipitation route in stirred tank reactor. For that purpose, combined influences of precursor, mixing technology and micromixing time on the final product physical properties were studied.Three mixing technologies were compared: a classic stirred tank reactor, a sliding surface mixing device and a rotor-stator mixer. Micromixing time ranges achievable with each of these reactors were determined using the iodide-iodate method. The study focused on the precipitation of two alumina precursors: boehmite, usually used, and NH4-dawsonite, which interest for catalyst supports preparation is quite recent. A model was developed to simulate the supersaturation evolution as a function of the micromixing time, based on boehmite precipitation kinetic equations.Characterization of NH4-dawsonite precipitated in a stirred tank reactor confirmed this precursor interest in order to prepare high porosity aluminas with mean pore diameters ranging between 10 and 30 nm. Study of the precipitation conducted in fast contacting mixers highlighted a significant difference in the behaviour of both precursors. Contrary to boehmite, NH4-dawsonite high sensitivity to micromixing time led to a wide range of textural properties.This thesis work therefore confirms the NH4-dawsonite potential as an alternative alumina precursor in order to reach new textural properties. The use of several precursor / mixing technology systems has also proven promising to cover a wide range of textural properties
Document type :
Complete list of metadata
Contributor : ABES STAR :  Contact
Submitted on : Tuesday, January 3, 2017 - 3:35:06 PM
Last modification on : Thursday, August 4, 2022 - 5:13:58 PM
Long-term archiving on: : Tuesday, April 4, 2017 - 2:29:39 PM


Version validated by the jury (STAR)


  • HAL Id : tel-01425446, version 1



Robin Lafficher. Nouveau procédé de précipitation pour la synthèse d’alumine. Génie chimique. Université de Lyon, 2016. Français. ⟨NNT : 2016LYSE1248⟩. ⟨tel-01425446⟩



Record views


Files downloads