Study On Gas Holdup And CFD Simulation Of Rotary Valve Tray

The rotary valve tray has the advantage of low entrainment,low weeping and high operating flexibility,but its gas holdup distribution has not been studied.Gas holdup of rotary valve trays and F1 valve trays was experimentally studied with air-water system in a 600mm ID organic glass column.Gas holdup of rotary valve trays was simulated by computational fluid dynamics performance software FLUENT6.3.And the simulation results were compared with the experimental results.Gas holdup of different gas and liquid loading on different height from tray floor was measured and calculated.The results show that the gas holdup increases and the gas holdup heterogeneity index decreases with the increase of height from tray floor.The gas holdup increases while gas loading increases and liquid loading decreases.The change trend of the rotary valve trays’ gas holdup is more even than that of the F1 valve trays’.Under the same conditions,the vertical distribution of the rotary valve trays’ gas holdup is more even than the F1 valve trays’,and the radial distribution of the rotary valve trays’ gas holdup is more even than the F1 valve trays’ when the height from tray floor is more than 40 mm.The gas-liquid distribution of rotary valve trays is more difficult to be influenced than that of F1 valve trays by the change of gas and liquid loading.Using computational fluid dynamics performance software FLUENT6.3,the gas holdup distribution of rotary valve trays whose rotating valves were fully opened was simulated.The results show that the gas holdup increases with the increase of gas loading and the decrease of liquid loading,and it also increases with the increase of the height from tray floor,and these all coincide with the experimental results.The results also show that the simulated gas holdup was slightly higher than the experimental gas holdup,but the two are very close.The error was in the acceptable range,that shows it is workable to forecast the gas holdup of rotary valve trays by using computational fluid dynamics performance software.This research work provides scientific basis for the engineering design and actual operation of rotary valve trays,and laid the foundation for in-depth study and improved optimization of rotary valve trays.