Evaluation of alkanolamine solutions for carbon dioxide removal in cross-flow rotating packed beds

A Review of Modeling Rotating Packed Beds and Improving Their Parameters: Gas–Liquid Contact

The aim of this review is to investigate a kind of process intensification equipment called a rotating packed bed (RPB), which improves transport via centrifugal force in the gas–liquid field, especially by absorption. Different types of RPB, and their advantages and effects on hydrodynamics, mass transfer, and power consumption under available models, are analyzed. Moreover, different approaches to the modeling of RPB are discussed, their mass transfer characteristics and hydrodynamic features are compared, and all models are reviewed. A dimensional analysis showed that suitable dimensionless numbers could make for a more realistic definition of the system, and could be used for prototype scale-up and benchmarking purposes. Additionally, comparisons of the results demonstrated that Re, Gr, Sc, Fr, We, and shape factors are effective. In addition, a study of mass transfer models revealed that the contact zone was the main area of interest in previous studies, and this zone was not evaluated in the same way as packed beds. Moreover, CFD studies revealed that the realizable k-ε turbulence model and the VOF two-phase model, combined with experimental reaction or mass transfer equations for analyzing hydrodynamic and mass transfer coefficients, could help define an RPB system in a more realistic way.

Extraction of dye from aqueous solution in rotating packed bed

The influence of centrifugal acceleration on mass transfer rates in liquid-liquid extraction was investigated experimentally in rotating packed bed (RPB) contactor. The extraction of methyl red using xylene was studied in the equipment. The effect of rotational speed (300-900rpm), flow rate of the aqueous (4.17-20.8×10(-6)m(3)/s), and organic phase (0.83-2.5×10(-6)m(3)/s) on the mass transfer performance was examined. The maximum stage efficiency attained was ∼0.98 at aqueous to organic flow rate ratio of 10. The results suggest that contactor volume required to carry out a given separation can be reduced by an order of magnitude with RPB in comparison to conventional extractors.

Binary VOCs absorption in a rotating packed bed with blade packings

This investigation addressed the mass transfer of rotating packed beds with blade packings in removing methanol and 1-butanol from binary mixtures by absorption using water as the absorbent. The dependences of the overall volumetric gas-phase mass transfer coefficient (K(G)a) on the inlet methanol concentration, the inlet 1-butanol concentration, the rotational speed, the gas flow rate, and the liquid flow rate, were explored. The results demonstrated that the inlet methanol and 1-butanol concentrations had a negligible effect on the K(G)a values of methanol and 1-butanol. The K(G)a values of methanol and 1-butanol increased with the rotational speed, the gas flow rate, and the liquid flow rate. The dependence of K(G)a on the gas flow rate was higher than that on the liquid flow rate, revealing that the mass transfer in binary VOCs absorption may be controlled considerably by the mass transfer in gas phase.