Study On Mechanisms Of The Spiral Interal Component In Process Intensification Of Foam Fractionation

It is a hot topic in foam fractionation to enhance foam drainage and improve enrichmentratio. Abundant literature have demonstrated that the development of new foam fractionationequipment is effective to enhance foam drainage. The thesis specifically investigated themechanisms of a novel component, the spiral internal component (SIC), in processintensification of foam fractionation. Based on the hydrodynamics of rising foam, the reason forenhancing foam drainage using the SIC was discussed, and a multistage drainage model wasestablished to determine the SIC performance in the enhancement of foam drainage. The SICwas applied to foam fractionation to improve enrichment ratio, and its performance undervarious conditions was investigated. Furthermore, the role of the SIC structural parameters inprocess intensification of foam fractionation was also investigated.The theorectical results presented that the SIC had no effect on the residence time of thefoam in the column; the SIC wall played a critical role in enhancing foam drainage while thecentrifugal force made slight contribution; with increasing the liquid holdup in the foam, the SICperformance in enhancing foam drainage was improved; with increasing the SIC stage number,the liquid holdup gradually decreased to an asymptotic value. The experimental results consistedwith the theorectical analyses.In an actual foam fractionation process, the SIC intensified bubble coalescence, speciallyfor the unstable foam. The SIC would have better performance in enhancing foam drainagewhen the rising foam had low surface viscosity. It also readily improved the enrichment ratio ofa surface active substance which had a high surface excess at the gas liquid interface.Volumetric gas velocity, pore diameter of the gas distributor and pH had more significant effectson the SIC performance than height of the liquid phase. With increasing volumetric gas velocityand pore diameter of the gas distributor, and pH deviating from the isoelectric point, the SICperformance in enhancing foam drainage and improving enrichment ratio was intensified. With decreasing the SIC thread pitch, and increasing its stage number and inclined angle,the ability of the SIC in enhancing foam drainage and increasing enrichment ratio was improved.The increase in the stage number also intensified bubble coalescence. Under suitable conditions,using the SIC of30mm in thread pitch,10in stage number and30oin inclined angle, the SDSand BSA enrichment ratios increased by60.1%and85.4%, respectively, compared with thoseobtained without the SIC.All above considered, it was effective for the SIC to enhance foam drainage and improveenrichment ratio.