Efficiency of Mixture Separation in Distillation Columns with Structured Packings under Conditions of Dynamically Controlled Irrigation

Abstract

The paper presents the results of an experimental study of separation efficiency and distribution of flow parameters over the cross-section of the distillation columns. The experiments were carried out on the large-scale research setup “Large Freon Column” with the diameter of 0.6 and 0.9 m. Experimental data were obtained at uniform and non-uniform irrigation of the Mellapak 350.Y and Sulzer 500X structured packings by the controlled liquid distributor. The mixture of refrigerants R114 and R21 was used as the working liquid at the pressure of 3 bar in the column. The liquid distributor with independently controlled valves for each drip point was used for controlled packing irrigation. Local temperature distributions of the liquid phase and counter-current vapor flow in the cross-section and over the packing height were recorded using a sequence of fast-response temperature sensors. Periodic irrigation of the structured packing can affect large-scale non-uniformity of mixture composition and flow parameter distribution over the cross-section and height of the transfer unit. Significantly non-uniform packing irrigation within a separate semiperiod leads to rearrangement of the structure of large-scale non-uniformity inside the packing. The new method for dynamically controlled irrigation of the packing is suggested. This method is aimed at destruction of stationary large-scale maldistribution over the column cross-section and achievement of higher separation efficiency of a completely wetted packing.