Korean Journal of Chemical Engineering, Vol.39, No.8, 2044-2054, August, 2022
Experimental studies of bubble cutting in a lab-scale micro-structured bubble column with different liquid viscosity
Bubble cutting was realized by installing a wire mesh in a micro-structured bubble column (MSBC) and studied experimentally with liquid viscosity range from 1 to 39.6mPa·s. A non-intrusive high-speed camera method was used to determine bubble size and size distribution. The changes of gas holdup, bubble size, size distribution and Sauter mean diameter before and after cutting were systematically studied with mesh openings of 3.8mm and 5.5mm. Three novel bubble cutting behaviors with uniform cutting, detachment cutting and indirect cutting behavior were observed. In the presence of two wire meshes, the bubble size distribution roughly shows a Gaussian curve distribution and the peak tends to shift towards lower diameters. With increasing liquid viscosity and superficial gas velocity, the dominant peak tends to move towards higher diameters, resulting in poor mesh cutting effect. After cutting, in the case of two wire meshes, the Sauter mean diameter decreased by 33.5% and 22.2% and the gas holdup increased by 3.2-12.2% and 1.2-4.4%, respectively. For the case of 3.8 mm mesh opening, the interfacial area increased by 10-26%, which is much better than 5.5mm mesh. The mean bubble size above the mesh will grow again and its growth rate depends on the liquid viscosity.
Keywords:Micro-structured Bubble Column;Bubble Cutting;Bubble Size Distribution;Liquid Viscosity;Wire Mesh