Enhancement Of Aqueous Alcohol Mass Transfer By 4A Molecular Sieve In Three-phase Bubble Column

Based on distillation process, the influence of 4A molecular sieve on aqueousalcohol mass transfer was experimentally studied in a three-phase bubble column with30mm in diameter and 600mm in height. The fine particles used in experiment are 4Amolecular sieve with diameter in the scale of 0.47μm ～ 4.0μm . The separatedsystems are tert-butyl alcohol—water and isopropyl alcohol—water. The relationshipbetween the solid particles and surface tension/apparent viscosity was separatelyapproached. In addition, by using the measured molar concentration of gas and liquidphase output, the influence of gas superficial velocity, solid content and mean particlediameter on gas-liquid mass transfer was analyzed in detail. In order to further characterize the mass transfer phenomena in the slurry system,an Axial Dispersion Model model was adopted to calculate the overall liquid-phasemass transfer coefficients under different superficial gas velocities, solid content andparticle diameters. It was found that the overall liquid-phase mass transfer coefficientscould be enhanced by particles in low solid content and would reach a peak with theincreasing of solid content. Then the mass transfer coeffcients would decrease withthe increasing of solid content. The ehancement effect would be strenthened with thedecreasing of particle diameters. The influencing mechanism of fine adsorbent particles to gas-liquid masstransfer was disscussed. And moreover, the effects of superficial gas velocities, solidcontent and particle diameters on the mixability of gas-liquid in column, bubblediameter, gas holdup, interfacial area of mass transfer and adhesion efficiency et alwere separately studied.