Abstract: Separation performance and tray efficiency of large-scale suspending downcomer trays for xylene column have been calculated by Aspen Plus. Influence on tray efficiency has been studied, considering the calculated result of gas and liquid loadings in the column. The simulation results show that the total tray efficiency can reach 72.0% under 83.4% feed loading condition; the total tray efficiency can reach 75.2% under 97.5% feed loading condition. The real gas loading in the column is over 110% of designed loading, while the liquid loading is about 113~135% of designed loading. Distribution of liquid on trays significantly affects the efficiency of suspending downcomer trays. Uneven distribution of liquid on trays may induce a lower tray efficiency under the condition of lower liquid loading. Feed distributor and directing baffles installed on tray deck can make distribution of liquid more uniform.

Key words: suspending downcomer tray, xylene column, tray efficiency