Experimental and CFD Simulation Study of the Air-Blowing Process of Iodine in Nitric Acid Solution

In this study, the air-blowing process of iodine in nitric acid solution was studied through experiments and computational fluid dynamic (CFD) simulation. The impact of superficial gas velocity and nitric acid concentration on the gas holdup and bubble distribution during bubbling is tested. population balance model (PBM) and interfacial area concentration model (IACM) models are selected to simulate the bubble coalescence and breakup, and the slip penetration model is used to simulate the mass transfer process. The experimental results show that the size of the bubbles in the nitric acid solution is smaller than that in the water due to Gibbs-Marangoni effect and electrical repulsive forces, resulting in a larger gas holdup and a wider bubble distribution. When the concentration of nitric acid solution exceeds 1 mol/L, the effect of nitric acid concentration variation on gas-liquid-phase hydrodynamics becomes less significant. The CFD simulation results showed that the PBM-(EMMS)Luo-Luo model can simulate the bubble coalescence and breakup in water, while the IACM-Hibiki-Ishii model is more suitable for those in nitric acid solution. In addition, it is found that the “slip penetration” model is suitable for the mass transfer calculation in the air-blowing process of iodine.