Investigation of gas–liquid dispersion and mass transfer performance of wide-viscosity-range impellers in water solutions of xanthan gum

Publication date: Available online 9 December 2019Source: Chemical Engineering Research and DesignAuthor(s): Baoqing Liu, Qing Xiao, Pengfei Gao, Bengt Sunden, Fangyi FanAbstractWide-viscosity-range impellers have extensive demands and applications in process industry. The gas–liquid dispersion and mass transfer characteristics of wide-viscosity-range impellers including Large-double-blade (LDB) impeller, Fullzone (FZ) impeller and Maxblend (MB) impeller in water solutions of xanthan gum were investigated experimentally and compared. The influences of gas flow rate, impeller speed and polymer concentration of liquid on the power consumption, overall gas holdup εg and mass transfer coefficient KLa were also analyzed. On this basis, the appropriate operating parameters and impeller type were determined. The results indicate that with rising flow rate, the higher εg and KLa can be achieved with a drop in power consumption, and a relatively high flow rate is recommended on the premise of guaranteeing the complete dispersal condition in aerated vessel. Higher impeller speed provides better gas–liquid dispersion and mass transfer performance, but results in more power consumption simultaneously. The appropriate impeller speed should be just enough to meet the requirements of εg and KLa. It also is found that the increasing concentration of water solution of xanthan gum adds to the complexity of gas dispersion and mass transfer in aerated vessel. Under the same specific power...

Source: Chemical Engineering Research and Design - December 9, 2019 Category: Chemistry Source Type: research