Research Of Mass Transfer Characteristics For The Cross-Type Valve Trays

The mass transfer performance was studied in a height of 4m, diameter of 750mm stainless steel column with 4 trays using cyclohexane-normal heptane as research media. The influences of hole area percent, outlet weir height and F factor on mass transfer efficiency of cross-type valve trays were investigated in total reflux and atmospheric pressure. The results showed that the mass transfer performance of cross-type valve tray with 13.56% hole area was the best one among the 8.22%,11.2%.13.56% and 15.69% hole area at reflux temperature 80～85℃. When the weir height was raised from 40mm to 70mm, the tray efficiency was increased about 10% for cross-type valve tray with 8.22% hole area and increased about 5% for cross-type valve tray with 11.2% hole area.Then the overall tray efficiencies of cross-type valve,sieve,F1 floating valve and combined directed floating valve were compared under the similar conditions.It is found that,with the close hole area percent, the overall tray efficiency of cross-type valve tray was between the F1 value tray and combination directed valve tray, and it was a little worse than the Combined directed valve tray. Moreover, AIChE,Chen, Chuang models and English-Van Winkle formula were used to calculate the tray efficiency, and the AIChE model is closer to the experimental value.The research results could provide the critical data for industrial application.