On the reliability of image analysis for bubble size distribution measurements in electrolyte solutions in stirred reactors

• The identification of gas-liquid flow regimes was achieved. • The quality of bubble detection varies with the flow regime. • The factorial design reveals the important parameters to optimize the bubble detection. • Analysing bubble size distribution in smaller regions of interest (ROIs) shows that ROI size affects the total number of detected bubbles. • The addition of NaCl affects bubble size distribution by inhibiting bubble coalescence. The translation of chemical processes from laboratory to industrial scale is crucial for the effective and sustainable implementation of new technologies. This transition presents significant challenges, particularly in multiphase systems where variations in physical chemistry can complicate scale-up efforts. A key aspect of this challenge is understanding bubble dynamics in gas-liquid systems, which are pivotal in processes such as hydrogen production and CO2 absorption. Bubble size significantly influences mass transfer rates and process efficiency, necessitating accurate measurement methods. A factorial design approach was employed to assess the sensitivity of results to key parameters. The findings provide quantitative guidelines for optimizing image analysis techniques and improving the accuracy of bubble size measurements in diverse operational conditions. This work advances the understanding of bubble dynamics in gas-liquid systems and offers practical insights for refining measurement techniques, ultimately supporting more effective scale-up of chemical processes.