Tray Design Challenges in Aromatics DWC

In 2011, ExxonMobil licensed a PXMax^SM paraxylene unit that employs a Dividing Wall Column to purify three products; Benzene, Toluene and mixed Xylenes. The tower internals are all trays in this case and there were some unique challenges to balance the pressure drop on both sides of the baffle. This paper will discuss the tray design employed by Sulzer and the challenges associated with that design. Tray design techniques for trayed Dividing Wall Columns will also be discussed. The tower has been in operation for a number of years and has been exhibiting better than expected tray efficiencies at design capacity.