Influence of arc baffle configuration on gas–liquid mass transfer in flat-plate bubble column

• Published in: Chemical engineering research & design 2021-01, Vol.165, p.129-136
• Main Authors: Chen, Zhijie, Zhang, Xinru, Su, Bosheng
• Format: Article
• Language: English
• Subjects: Baffle; Bioreactors; Bubble column; Bubble columns; Computational fluid dynamics; Flow velocity; Fluids; Gas flow; Gases; Gas–liquid mass transfer; Mass transfer; Membrane reactors; Numerical simulation; Shape effects
• ISSN: 0263-8762; 1744-3563
• DOI: 10.1016/j.cherd.2020.10.024

•The ‘n’ shape baffle achieved a higher mass transfer coefficient than ‘u’ shape and horizontal baffles.•Mass transfer coefficient increase first and then going to stabilize with the increase of bottom clearance (H).•Mass transfer in flat-plate bubble column can be enhanced by a baffle with a larger projection length of baffle (L).•Mass transfer coefficient of the ‘n’ baffle (L=80mm and R=50mm) is about 44.5–170% higher than horizontal baffles. Installation of baffles in bioreactor is a promising method to improve the gas–liquid mass transfer. This work aims to understand the effect of arc baffle (‘n’ and ‘u’ shape) on gas-liquid mass transfer in flat-plate bubble column. Based on the numerical approach, the effects of three parameters of arc baffles on the CO2 gas–liquid mass transfer were studied, i.e., the projection length of baffle (L=40, 60, 80mm), the curvature radius of baffle (R=50, 70, 90mm and horizontal baffle means R=∞mm) and the bottom clearance (H=50, 100, 150, 200, 250, 300mm). The mass transfer model was validated, the experimental and numerical results are in good agreement at gas flow rate of 1 to 3Lmin−1. The results indicated that the overall volumetric mass transfer coefficient (KLa) for the ‘n’ and ‘u’ shape baffles both increased with the increasing L and H. For the ‘u’ shape baffle, the effect of R on KLa is low. Whereas, for the ‘n’ shape baffle, the KLa increased with the decreasing R. In addition, the results showed that the KLa of flat-plate bubble column with the ‘n’ shape baffle (L=80mm, R=50mm) can be increased by 44.5–170% compared with that with the horizontal baffle.