Mass transfer characteristics of low H/D bubble columns

The mass transfer characteristics of 0.2, 0.6 and 1.0 m diameter bubble columns having a low height to diameter ratio (0.6 < H/D < 4) and operated at low superficial gas velocities (0.01 < VG < 0.08 m/s) were investigated. Different types of spargers were used to study their effect on the column performance. The values of effective interfacial area, a, and volumetric mass transfer coefficient, kLa, were measured by using chemical methods. The values of a and kLa were found to vary from 40 to 420 m2/m3 of clear liquid volume and from 0.01 to 0.16 s−1, respectively, in the range of VG, and VL covered in this investigation. The value of the liquid‐side mass transfer coefficient, kL, was found to vary from 3 × 10−4 to 7 × 104 m/s. The effect of the physical properties of the system on the values of a was also investigated. The height to diameter ratio and the column diameter did not have significant effect on the values of gas holdup, a and kLa. It was found that the sparger design is not of critical importance, provided multipoint/multiorifice gas spargers are used. The comparative performance of bubble columns having low H/D with horizontal sparged contactors and tall bubble columns has been considered.