Fluid dynamic and separation performance of foam loaded packed distillation columns

Abstract

Foam formation in distillation columns leads to various negative effects such as reduced distillation throughput and reduced separation performance. In order to determine the influence of foam on distillation throughput and separation performance, measurements with chlorobenzene/ethylbenzene (CB/EB) and water/monoethyleneglycol (water/MEG) mixtures in a DN50 laboratory distillation setup were carried out. As internals, structured packings were compared to randomized packings with different materials. Results show that structured packings were more susceptible to foam and had greater losses in separation performance under the influence of foam as compared to randomized packings. However, in absolute terms, foam-loaded structured packings showed the highest separation efficiencies compared to randomized packings. An increase in column wall temperature above adiabatic conditions resulted in an increased foam loading and a decreased separation performance. Pressure drops were similar between packings, but foam loaded randomized packings showed a slightly lower pressure drop.