https://doi.org/10.3390/su14116559
“In the setup of this work, the gravity ratio increased from 30.06 to 219.04 from the inner radius of the packing to the outer radius, and from 53.45 to 389.40 at the low and high rotating speeds of the rotor, respectively. Regarding this issue, it was necessary to survey the effect of the rotating speed on the MT volumetric coefficient. Figure 3 shows the values of kLa of pure water and various NFs versus the CO2 content of the gas feed, which reveals how the concentration of NPs and kind of NPs affected the MT performance. It was also found that the MT coefficient of Al2O3 NF- 0.01 wt at high/low rotating speeds (Figure 3a) and TiO2 NF-0.05 wt.% were the highest values (Figure 3b), and the Al2O3 and TiO2 NFs’ MT volumetric coefficient v alues were higher than those of the SiO2 NF at a concentration of 0.1 wt.% (Figure 3c). Figure 3d demonstrates that an increase in the rotating speed of the RPB led to an increase in the kLa values. The figure indicates that there was a relationship between kLa and the rotor speed. It also reveals that higher rotor speeds improved aw. Therefore, the ae values change along the radius for solvents, as reported by Agarwal et al. [82], and are influenced by changes in the NF concentration, type of NF, and CO2 content. This may be due to the microconvection ability of NPs and its dependency on concentration values. A higher amount of CO2 content also makes for a higher driving force due to further concentration differences between the phases.”

“Figure 3. Volumetric MT coefficient (kLa) of NFs vs. CO2 content at gas flow rate of 10 L/min, solvent flow rate of 30 L/h in high and low rotating speed. (a) 0.01 wt.% NFs, (b) 0.05 wt.% NFs, (c) 0.1 wt.% NFs and (d) pure water.”