Centrifugal classification of pseudo-boehmite by mini-hydrocyclone in continuous-carbonation preparation process

Abstract

Pseudo-boehmite (PB) is often used as a precursor for hydrotreating catalyst support (γ-Al2O3) in the petroleum refining process. Recently, continuous-carbonation process was proposed to prepare PB in order to meet the increasing demand for macroporous γ-Al2O3, but the highly dispersed particle size of PB in this process limited its development. To obtain the PB with monodispersed particle size, a 10mm mini-hydrocyclone was designed by 3D printing technology and used to the classification for PB. Then a high-performance zone for classification with Re of 4000–5000 was obtained. The volume ratio of particles (>10μm) was increased from 56.3% to 83.5% at a split ratio of 15%, and the mean particle size was increased from 12.9μm to 45.7μm, which indicated that the highly dispersed particle size could be efficiently concentrated into monodispersed one by hydrocyclone classification. Under optimal operating conditions (Re of 4360 and Rf of 15%), the hydrocyclone was unprecedentedly applied to the continuous-carbonation preparation process of PB, and the volume ratio of particles (>10μm) was significantly increased from 53.1% to 75.6% in the pilot test. This finding contributed to optimize continuous-carbonation process and improve product performance.