Measurement of behavior of gas bubbles a

This study investigates fundamental properties of gas bubbles such as gas holdup, bubble frequency, bubble length, and bubble rising velocity in a slurry bubble column using a dual electroresistivity probe method. Measurements of radial distribution revealed that the local gas holdup exhibited a parabolic profile when the mean solid holdup was less than 0.2; however, beyond this threshold, the gas holdup decreased significantly in the central region of the column due to bubble concentration. The cross-sectionally averaged gas holdup agreed closely with predictions provided by Koide's equation for heterogeneous flow in slurry bubble columns. The cumulative bubble length distribution followed a log-normal distribution, while the cumulative bubble rising velocity distribution adhered to a normal distribution. Additionally, variations in superficial gas velocity were found to have minimal impact on these distributions within slurry bubble columns with high solid content. When superficial gas velocity exceeded approximately 4 cm/s, median values of the distributions increased compared to those in a conventional bubble column, although the variance for bubble length in the slurry bubble column was similar to that in the bubble column.