Effect of the angle of rotation of structured packing layers on separation efficiency in distillation column

Abstract

It is well known that a good quality of liquid distribution over the surface of structured packings is crucial for high performance of large diameter columns. The angle of rotation of the packing layers and their number are among the main parameters characterizing the distribution of liquid in a structured packing over the column cross-section and height. This paper presents investigation results on the influence of the rotation angle of structured packing layers on separation efficiency, pressure drop, distribution of local composition of mixture and local liquid flow rate under the packing. The experiments were carried out in distillation column with the internal diameter of 0.9 m on a structured packing with a specific area of 500 m2/m3, and the corrugation angle of packing equal to 45°. The mixture of refrigerants R114 and R21 at the pressure of 3 bar and total reflux was used as the working fluid. The column was packed with 11 packing layers with rotation angles of 20, 45, 70, and 90 degrees. According to experimental results, a decrease in the angle of packing layer rotation from 90 to 20 degrees leads to a decrease in separation efficiency, while the HETP value increases by 10–12%.