Effect of distributor type on microbubble dispersion in a pressurized bubble column

• Published in: Chemical engineering research & design Vol. 174; pp. 188 - 198
• Main Authors: Bae, Keon, Kim, Jun Young, Go, Kang Seok, Nho, Nam Sun, Kim, DongJae, Bae, Jong Wook, Lee, DongHyun
• Format: Journal Article
• Language: English
• Published: Rugby Elsevier Ltd 01.10.2021; Elsevier Science Ltd
• Subjects: Bubble columns; Bubbles; Diameters; Distributor; Distributors; Dynamic gas disengagement (DGD); Evaluation; Flow velocity; Gas holdup; Gases; Geometry; Hole size; Kerosene; Low flow; Microbubble; Perforated plates; Pressurized bubble column; Gas holdup; Distributor; Microbubble; Dynamic gas disengagement (DGD); Pressurized bubble column
• ISSN: 0263-8762; 1744-3563
• DOI: 10.1016/j.cherd.2021.08.009

Motion capture of rising bubbles with two types of distributors at Psys = 3.5 MPa and Ug = 12.3 × 10−3 m/s. [Display omitted] •Effect of distributor geometry on hydrodynamic characteristics in a low surface tension liquid system is determined.•Generation of microbubbles is analyzed using a dynamic gas disengagement (DGD) method.•High-speed camera images taken from various distributors are analyzed. The effect of distributor geometry on bubble characteristics in an air–kerosene system of a pressurized bubble column was evaluated. The experiment was carried out using a cylindrical stainless column with an inner diameter of 0.097 m and a height of 1.8 m under a system pressure up to 3.5 MPa. The gas holdup was calculated under pressure taps from 0.05 m to 0.85 m above the distributor along axial direction of the column. Bubble size was measured with an optical probe installed 0.5 m above the distributor. Perforated plates with four different hole sizes including 0.8 mm (20 each), 1 mm (12 each), 2 mm (3 each), and 3.46 mm (1 each) fixed with the same opening fraction (ϕo = 0.128%) were evaluated. Different opening fractions at 0.223% (21 holes), 0.128% (12 holes), 0.074% (7 holes), and 0.032% (3 holes) were also tested with a constant hole size (1 mm). The effect of the distributor geometry on bubble characteristics was determined with seven different types of perforated plates. The number of microbubbles was increased with decreasing opening fraction of the distributor. Based on dynamic gas disengagement (DGD) analysis, microbubbles were rarely generated in all distributors under conditions of Psys = 0.1 MPa at Ug = 12.3 mm/s. However, a significant number of microbubbles were generated at ϕo = 0.032% despite a low flow rate at Psys = 3.5 MPa. Microbubble ratio varied from 36% to 40% at ϕo = 0.128 %, while this ratio varied from 38% to 73% at ϕo = 0.032%.