Determination of mass transfer and hydrodynamic characteristics of fluids in cocurrent downflow contacting reactor (CDC)

Ill SUMMARY Master Thesis DETERMINATION OF MASS TRANSFER AND HYDRODYNAMIC CHARACTERISTICS OF FLUIDS IN COCURRENT DOWNFLOW CONTACTING REACTOR (CDCR) Ramazan ORHAN University of Fırat Graduate School of Natural and Applied Science Department of Chemical Engineering 2001, Page 81 A Co-current Downflow Contacting Reactor (CDCR) has some advantages compared to conventional gas-liquid contactor, since It increases efficient of mass transfer in the liquid phase. Therefore in this study, the transfer of oxygen from gas phase to the liquid phase was investigated by using CDCR. The CDCR utilised the kinetic energy of high velocitiy liquid jet in order to entrain and disperse the gas phase from top of the column. The kinetic energy of the gas-liquid jet entering column produced intense turbulence and mixing a dense matrix of gas bubbles was formed from top of the column downwards to the point of the bottom column. In this work, hydrodinamic conditions and mass transfer characteristics of the co- current downflow contacting reactor were studied for different liquids and varied concentrations of glycerol for 2, 3 and 4 mm orifice diameter. Volumetric mass transfer coefficient {kid) and gas holdup values were increased with increasing liquid and gas flow rates for each orifice diameter. Gas holdup, faü and dispersion height values determined for air-water system were higher than the values of both air-%0.5 glycerol and air-%0.5 glucose.IV To determine the avarage bubble diameter for each condition, photographic techniques were used, and the diameters of bubbles were measured as 3.867 mm, 3.445 and 2.853 mm for air water, air-%0.5 glycerol and air-%0.5 glucose, respectively. In addition, the effects of hydrodynamic conditions and liquid properties on bubble diameters and formation were determined. Key words: Co-current downflow, mass transfer, gas holdup, dispersion height