Experimental Study On Hydrodynamic Parameters Of Air-water Microbubble System And Air-acetic Acid System In Bubble Columns

Bubble column reactors are widely used in chemical,petrochemical,environmental,biochemical and other industries as multi-phase contactors and reactors because of its many advantages,such as good effect of gas-liquid mass transfer and heat transfer,easy operation,convenient maintenance and so on.It is very important to understand the hydrodynamics of "bubble scale" and "reactor scale" for the design,scale-up and optimization of bubble columns.In this paper,electrical resistance tomography technique,dual-tip fiber optical probe technique and differential pressure method are used to study the influence of air-water microbubble system and air acetic acid solution system on the hydrodynamic parameters in the bubble column,and the related content is numerically simulated by CFD.The results show that when the foam gun as a gas distributor,the gas holdup in the column is higher than traditional gas distributor,the chord length distribution of bubbles is narrower,the flow regime is more stable,and the foaming effect is better.At the same time,it is also found that when the foam gun is used as the gas distributor,the effect of different column diameters on the hydrodynamic parameters in the column is neglected.For air-acetic acid solution systems,the effects of superficial gas velocity and physical properties of acetic acid at different concentrations on the hydrodynamic parameters in the column were investigated.The results show that the gas holdup in the column increases with the increase of superficial gas velocity.And the effect of different concentrations of acetic acid solution system on the average gas holdup is dual effect.It shows the gas holdup increases with the increase of acetic acid concentration.When the acetic acid concentration is about 20%,at the same superficial gas velocity,the gas holdup is the highest,and then with the increase of acetic acid concentration,the gas holdup decreases.The trend of hydrodynamic parameters in the column under different acetic acid concentration was simulated by CFD numerical simulation.The simulation results show that the simulation results are in good agreement with the experimental results in terms of radial gas holdup,and CFD can give the radial liquid velocity distribution in the column.