Computational Fluid Dynamics Based Modeling of Gas Absorption Process: A State-of-the-Art Review

The effective removal of gas phase species relies on effective gas liquid hydrodynamic contact coupling with fast chemical reaction rates. To promote mass transfer rate and the development of reagents, computational fluid dynamic modeling has long been recognized as an effective methodology for the quantification of physical and chemical parameters. The simulation of the gas liquid process involves the coupling of models including multiphase flow, turbulence, interfacial forces, mass transfer, and chemical reactions. The selection of suitable models according to practical applications has been challenging. In terms of multiphase flow, volume of fraction, Euler–Euler, and Euler–Lagrange approaches are discussed. With regard to turbulence, direct numerical simulation, large eddy simulation, and Reynolds averaged Navier–Stokes approach are compared. With respect to interfacial forces, the dominance of drag, lift, virtual mass, wall lubrication, and turbulent dispersion forces for different situations are obtained. In terms of mass transfer, the development and applications of film model, dimensionless analysis, penetration model, and surface renewal model are discussed. Different methodologies to enhance mass transfer include improvement of equipment structure, addition of nanofluid, and exposure to an energy field are summarized. To accelerate the computational process, four methods including the space–time conservation element and solution element model, compartmental model, reduction in dimension, and multiscale approach are discussed. This paper intends to provide a thorough review on the applications of different models to different situations and, in particular, to reveal the restrictions of different models. Overall, this study lays the foundation for future studies on the optimization of scrubbers for large scale practical applications. It also allows a deeper understanding of the interactions of fluid dynamics, mass transfer, and chemical reactions.