Fabrication and characterization of low-cost silica spargers: Toward smaller bubbles

In this study, nano-and microstructured glass bead spargers were fabricated by an innovative pressureless sintering method in a temperature-controlled convection furnace. In comparison to existing commercial spargers, the spargers fabricated in the present study produce bubbles smaller than 100 lm in size. The novelty of the research is in the fabrication step of the spargers and in the study of bubble columns with bubbles in the range of 0.1 mm up to 1 mm. Scanning electron microscopy, X-ray diffraction, and porosimetry were used to further characterize the fabricated spargers. The bubble sizes and distributions were determined in an experimental setup comprising a bubble column equipped with a semiprofessional camera to record the sizes and movements of the bubbles in the column. Computational fluid dynamics modeling performed using Fluent was further used as a diagnosis tool to improve our understanding of the velocity profiles and x-y coordinates of the bubbles and gas holdup in the column. (C) 2016 The Society of Powder Technology Japan. Published by Elsevier B.V.