The Evaluation of Out-of-Level Trays for the Improvement of Industry Guidelines

Industry guidelines have been developed from operational experience to predict the tray tilt angle that can be allowed without sacrificing tray operational performance. There can be a negative economic impact when operating a column with permanently tilted trays whether it is reduced throughput, purity or increased utility consumption. As a result, the validity of the industry tray guidelines has been questioned. Pilot plant experimental data was combined with an industrial example to elucidate the effect of tray tilt angle, specifically perpendicular to liquid flow, on the performance of a distillation column tray. A new guideline for the upper limit of the tray tilt angle has been developed thus providing industry confidence in deciding when to correct a tray tilt. A theoretical model has also been proposed that matches, within 5%, experimental and industrial data for a tilted tray, perpendicular to liquid flow, for diameters up to 1.7 m.