Homogeneous and heterogeneous distillation of ethanol-benzene-water systemby packed column with structured packing

An experimental study is made on mass transfer in a packed distillation col umn with the structured packing covering homogeneous and heterogeneous liqu id regions for an ethanol-benzene-water system under total reflux condition s. The vapor phase diffusion fluxes obtained in the homogeneous liquid regi on agree Hell with the correlation derived from an acetone-ethanol system b y Olano et al. (1995). On the other hand, the observed diffusion fluxes in the heterogeneous liquid region exhibit Hide scattering, which mag be due t o the neglect of the liquid phase resistance and the assumption of three-ph ase equilibrium at the vapor-liquid interface in this experimental analysis . In order to examine the effect of liquid phase resistance on the separation performance in the packed distillation column, its simulation is also carr ied out by considering or neglecting the liquid phase resistance. The liqui d phase resistance has much influence on the vapor phase concentration driv ing force, and then the diffusion and convective mass flux in the heterogen eous liquid region, The top concentrations and reflux flow rates predicted by considering the liquid phase resistance agree reasonably well with the e xperimental data in the heterogeneous liquid region. On the contrary, the e ffect of the liquid phase resistance on the separation performance in the h omogeneous liquid region is very small as generally accepted.