CROSS-CURRENT PACKED TRAY FOR A DIABATIC PRODUCT-CONCENTRATING COLUMN

Diabatic rectification is one of the ways to increase the energy efficiency of the mixed distillation process. Diabatic units in which partial condensation of rising vapours and further evaporation of the condensate on contact devices placed on trays have proved effective. Horizontal perforated plate units are promising in this respect. They have low resistance and high efficiency, but have a narrow operating range. To intensify the separation process and increase column productivity, a combined cross-flow packed tray was developed and investigated. It consists of a spiral-prismatic packing placed in coaxial perforated cups and profiled plates, allowing the slurry to flow continuously downwards and preventing condensate from entering the evaporation zone. This type of tray design has made it possible to intensify the process of heat and mass transfer in the vapour and liquid phases and to extend the operating range of the tray. The results of the experimental study of the developed tray in a pilot rectification column are presented. The distribution of the concentration of ethanol in the liquid flowing down the plates is shown. The effective temperature difference for mist evaporation on the profiled plates and condensation under the plates is determined. The value of the heat transfer coefficient of the heat flow on the plate is determined. Comparison of characteristic parameters of adiabatic column with spiral-prismatic packed countercurrent type with a diabatic column with cross-flow trays is made and the advantage of the latter is shown. For the construction of low tonnage product concentrating columns, also under vacuum, the developed trays are recommended.