Optimal design of a microbubble cap to enhance mass transfer efficiency using image processing

Microbubble technology has been used in various industries to improve the mass transfer efficiency of applications. Although conventional bubble generators using venturi and swilling nozzles are useful, their low gas throughput is insufficient for industrial pollutant reduction. Hence, this study developed an optimal microbubble cap structure with a high gas throughput and microbubble generation rate using an image processing based overall mass transfer coefficient (OMTC) calculation model. Micro bubble cap with brim structure was developed, and the bubble generation pattern by varying the brim size was analyzed in a lab-scale microbubble system. Bubble diameters were measured using image processing and OMTC was calculated using bubble size. The observed bubble size range was approximately 0–250 μm, and the bubble generation ratio was the highest at a 5-mm-brim size. When calculating the OMTC of H₂S in water of 50 μm or less, the value increased by more than 50% compared to other brim-size cases. Therefore, at brim sizes of 5 mm, the dispersion and production of microbubbles were active, and they were expected to endow high mass transfer efficiency.