(200a) Evaluation of the Axial Mixing and of the Mass Transfer Coefficients in the Distillation Column

In our previous paper we assessed success of the recalculation of the mass-transfer data from absorption to distillation conditions when the procedure took into the account the axial mixing of the liquid phase or when the usual assumption of the plug flow was introduced. The absorption data in the form of the volumetric mass-transfer coefficients were measured in the absorption column of inner diameter of 0.29m using proven aqueous test systems. The liquid phase Bodenstein number quantifying effect of the axial mixing has been measured in the same absorption column with the air – water system. These data were used for calculation of the distillation HETPs using BS model to transfer the data from absorption conditions to distillation ones. The comparison was made against the experimental distillation data in the form of HETP.

In this contribution we present results of the evaluation of the volumetric mass-transfer coefficients and of the liquid phase Bodenstein number directly from the distillation experiments performed under the total reflux in the 0.15m atmospheric column using C₆/C₇ and methanol/n-propanol systems.

This procedure enables to compare the raw values of the mass-transfer coefficients and utilization of the HETP is avoided. Thus the comparison not only qualitatively assesses success of various recalculations, but provides direct comparison of the mass-transfer coefficients and the liquid phase Bodenstein number for both processes.