Absorption in wetted-wall column with phase properties close to distillation conditions

Abstract

Our present research re-opens the problem of recalculation of the mass-transfer data between absorption and distillation by performing both processes in devices of the same geometry and using absorption and distillation systems whose physical properties are as similar as possible. The wetted wall column has been chosen as an experimental device which assures identical and known effective interfacial area for both processes. In this paper we present results of the absorption experiments while the follow up article will focus on the distillation ones and their mutual comparison. The liquid side mass-transfer coefficients were measured using desorption of oxygen from primary alcohols to the stream of nitrogen in the range of the liquid phase Reynolds numbers from 30 to 560. The experiments were carried out at ambient and at elevated temperatures providing the range of liquid phase Schmidt numbers from 66 to 1300. The gas phase mass-transfer coefficient was measured using absorption of sulfur dioxide from various carrier gasses-air, helium and sulfur hexafluoride-into the sodium hydroxide aqueous solution for Reynolds numbers from 300 to 11,800. Due to the significantly different properties of the carrier gases the range of the gas phase Schmidt number from 0.45 to 2.75 was achieved. The range of Reynolds numbers and Schmidt numbers covered by the absorption experiments overlaps the range of the distillation experiments, thus no extrapolation will be needed for the recalculation of the mass-transfer coefficients from absorption to distillation conditions. The results of the absorption experiments have been correlated in the dimensionless form ShL=0.33ReL0.12ScL0.47 and ShG=0.012ReLG0.90ScG0.61 with RSD of 6% and 4% respectively.