Revealing instantaneous gas-particle segregation in bubbling and turbulent fluidized beds through fiber optic sensing

Bubbling and turbulent fluidized beds (BFB and TFB) are widely used in the chemical and energy industries, owing to their enhanced heat transfer and improved operation flexibility. In BFB and TFB, the gas-particle suspension is featured with a dilute phase (bubbles) and a dense phase. The gas exchanges between the bubbles and the dense phase often through an intermediate region, further enhancing the gas-particle contact. However, few comprehensive studies have been conducted on the intermediate region and the dense phase. In this work, the instantaneous solids holdup was obtained in BFB and TFB through optical fiber sensing. Subsequently, through the use of statistical signal analysis, solids holdup thresholds were proposed to discriminate between the bubbles, the intermediate region (named as ‘mid-phase’) and the dense phase. Finally, gas-particle segregation details were further revealed through the quantification of the different phases to advance the development of future modelling, design and scale-up processes.