Study And Optimization Of The Performance Of Inline High Shear Mixers In Liquid-liquid Systems

High shear mixers(HSMs)are novel kinds of process intensification devices.With the advantages of high shear rates and highly localized energy dissipation rate,HSMs can significantly improve the surface renews rate between the liquids and create small-uniform droplets,thus having a great application prospect in these fields.To give a guidance to the Liquid-liquid(L-L)process,the L-L mass transfer and emulsification capacities in the inline-HSMs were studied in this thesis.Firstly,the L-L mass transfer performance of blade-screen and teethed inline HSMs were investigated by kerosene-benzoic acid-water extraction system.The effect of different rotor speed,two phases flow rates,surfactant concentration on extraction efficiency(E)and overall volumetric mass transfer coefficient(KLa)were studied.The experimental value of KLa were correlated with the operating parameters.The experimental results show that both E and KLa increase with the increase of the rotor and aqueous flow rate,E decrease with the increase of organic flow rate while KLa increase slightly with the organic flow rate.With the increase of surfactant concentration,Both E and KLa increase firstly and then decrease.Secondly,the effect of stator geometry of the blade-screen inline HSMs on the emulsification and extraction process were investigated.The droplet size and overall volumetric mass transfer coefficient of different opening shapes(circular,rhombus,“s” hole,teethed,crisscross)and numbers(30,60,120,480)were studied under the same opening area.The experimental results show that the opening shapes has little effect on the droplet size and mass transfer coefficient,while the opening number can significantly affect these parameters,the emulsification and mass transfer performance has optimal value with the increase of the opening number.The fluid power consumption of the HSMs varies a little with the opening shapes,but it increase firstly and then decrese with the opening number with an obviously trend.The energy dissipation rate(?)of the HSMs were studied by the CFD simulation,? of the rotor and screen region increase with the openning number,but it has an opposite trend in the jet region.Therefore,The total energy dissipation rate increase firstly and then decrease with the opening number.In this thesis,the circular screen with an opening form 2.4mm ×120 has the best emulsification and mas transfer performance.