This paper presents and compares the mathematical models and computational fluid dynamics (CFD) models for degassing of oxygen from water in a laboratory-scale multi-function gas-liquid contactor under various operating conditions. The optimum correlations of the overall volumetric liquid-phase mass transfer coefficient (kLa) are determined by the mathematical models of specific contactors. Both the continuous-reactor model and semi-batch model can evaluate the degassing efficiency with relative errors within ±13%. Similarly, CFD models agree with experimental data with relative errors of ±10% or less. Overall, the mathematical models are deemed easy to use in engineering practice to assist the selection of efficient contactors and determine their optimum operation parameters. The CFD models have a wider applicability, and directly provide the local mass transfer details, making it appropriate for harsh industrial scenarios where empirical correlations for important quantities are unavailable. Combining these two types of models can effectively guide the design, optimization, and operation of the high-throughput degassing system.

The cyclonic micro‐bubble flotation column (FCMC) is an efficient flotation device for the separation of fine minerals, but its mechanisms are rarely studied using computational fluid dynamics (CFD). This paper reports the air–water two‐phase computational fluid dynamics‐population balance model (CFD‐PBM) simulations for the column flotation unit of an FCMC. The shear stress transport (SST) k‐ω model with curvature correction (CC) is used to simulate turbulence effects. Then, the interphase forces models considering bubble size distribution are selected according to the experimental data in a bubble column, which is in analogy to the column flotation unit of the FCMC. Finally, the optimal combination of interphase forces models (i.e., the Ishii–Zuber drag force model, the Hosokawa–Frank wall lubrication force model, and the Lopez de Bertodano turbulent dispersion force model) is applied to simulate an FCMC with a superficial gas velocity of 0.0144 m/s. The results show that the CFD‐PBM simulation can achieve a relative error of 9.09% for gas volume fraction and −5.45% for bubble rising velocity, indicating the reliability of the selected combination of interphase forces models.

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