Bubble column reactors are quite popular in the chemical, biochemical and petrochemical industries due to their relative simple construction; favourable heat and mass transfer properties and low operating cost. Among the various design parameters, column configuration (size) has a direct impact on the overall throughput. In this study, an experimental investigation of bubble column configuration on its hydrodynamic has been conducted with three different sizes of bubble column (ID = 10 ~ 45 cm). A comparison in terms of the overall gas holdup as well as localized bubble properties is performed using the Four Point Optical technique and hydrodynamic similarities / dissimilarities are discussed at a constant gas flow rate.
Experiments showed that the overall gas holdup was a function of the gas flow rate. For the range of gas velocity studied (9.5–22.3 cm3/min), the smaller column had 50–60% more holdup than the bigger column. Radial profiles of local gas holdup, specific interfacial area, bubble rise velocity and bubble frequency at constant flow rate had exhibited similar behaviour (i.e. higher values for the smaller column). In conclusion, the effect of column configuration showed relatively higher values of overall gas holdup and bubble properties in the smaller column. This study provides a data base as a benchmark which can be used to improve the understanding of the configuration effect and hence the overall performance of bubble columns.