Hydrodynamics And Mass Transfer In Airlift Loop Slurry Reactors

Airlift loop slurry reactors have been widely used for petrochemical, biochemical, energy and environmental processes. Due to the complexity of the flow behavior and mass transfer in multiphase systems, there are still many remaining problems. Studies on the hydrodynamic behavior and mass transfer in such reactors can provide guidance in optimizing existing reactors or developing and designing a novel reactor for high performance, which is very important because of the more urgent energy and environmental problems. In this work, the hydrodynamic behavior and mass transfer in an airlift loop slurry reactor were investigated by both experimental measurements and mathematical models.The effects of superficial gas velocity, fine particle concentration, flow resistance and liquid level in the separator on the gas holdup, bubble size and its distribution, bubble rise velocity and liquid velocity were investigated by the pressure difference, optic fiber, LDV and tracer impulse methods. A hydrodynamic model was established based on momentum balance and energy balances. There is satisfactory agreement between the measured and calculated results of the gas holdup and liquid velocity.In industrial applications where fine particles are used as the catalyst, increasing the fine particle concentration can decrease the equipment size and cost. But an increased fine particle concentration decreases the gas holdup and inter-phase mass transfer, this made it important to find an effective method to increase the gas holdup and inter-phase area, which is important to intensify inter-phase mass transfer. The effects of adding an internal and large particles on increasing the gas holdup and intensifying mass transfer were investigated. Both of these can increase the gas holdup and intensify mass transfer.The axial dispersion model was applied to the riser and down-comer, respectively, and a mathematical model was developed to describe the residence time distribution (RTD) characteristics of an airlift loop reactor. By neglecting the effect of...