Simulation And Hydrodynamics Characteristic Of Gas-liquid In A Multi-stage Bubble Column And A Internal Loop Reactor Based On The Ert Method

Owing to the ease of operation, simplicity of column construction andmaintenance, low energy consumption and higher mass, heat transferefficiency, the multi stage bubble column and the airlift internal loop reactorare commonly used in industrial applications requiring gas–liquid andgas–liquid–solid contact. However, because of the complexity of gas liquidflow, the theoretical research and experimental method of bubble column staystill a developing stage. It is great significance to study the scale up andoptimization of bubble columns.In these studies, the measurement of hydrodynamics parameters and themixed characters were researched and simulated with2000mm height,282mm diameter of multi stage bubble column and airlift internal loop reactor(1240mm height,165mm diameter) by using Electrical ResistanceTomography (ERT) technology and Computational Fluid Dynamics (CFD).The effect of operating parameters (superficial gas velocity) and platestructural parameters (perforated plate, tongue plate and draft tube) on thehydrodynamics parameters of column, such as gas holdup, water velocity,bubble characteristics, gas cap height and so on, are studied in a multi stage bubble columns. With the increasing of the superficial gas velocity, the gasholdup and water velocity in the multi stage bubble column increase. With adecrease of the percentage free area, the hole diameter and tongue angle, thegas holdups below the perforated plate increases more greatly. Moreover, theaddition of perforated plate enhances eddy strength in bubble column and thecoalescence and breakup of bubbles become seriously.The hydrodynamics in the internal airlift loop reactor with different draftare measured and simulated using ERT method and CFD. The results showthat gas holdups in the rise area and the down comer are increased with thesuperficial gas velocity added. With the decrease of draft tube diameter, thegas holdup and gas liquid velocity in rising zone increase. However, the gasholdup and gas liquid velocity in the down comer decreased. The bottom gapdistance of draft tube almost has no effect on hydrodynamic characteristic inrising zone. But, the gas holdup and gas liquid velocity in down comer areincreased with the bottom gap distance of draft tube added.