Large Diameter Tray Design – Challenges and Solutions

The average diameter of a typical distillation column has increased significantly over the past 20 years as plant nameplate capacities have grown at an accelerated pace.  Figures 1 and 2 show the historical plant sizes of UOP’s Oleflex™ Process for propane dehydrogenation, and PAREX™ Process for para-xylene production.  Column diameters exceeding 10 meters in new Propylene and Aromatics separations are becoming more commonplace.  As in the past, large column diameters today continue to pose new challenges for the design, supply, and installation of column internals in addition to the fabrication, transportation and erection of the column shell. UOP MD™ trays have an extensive experience base in these large columns due to their unique geometry, allowing reliable scale-up in addition to reduced capital and production costs as a result of lower diameter and column height.  This paper discusses the evolution of mechanical improvements to UOP trays in the last forty (40) years, how these improvements are utilized today, and potential future developments to further reduce capital costs in large column diameters.