| Combined Trapezoid Spray Tray(CTST)has been widely used in petroleum, chemical, pharmaceutical and other chemical industries for its structural features and advantages. As a new tray, the research of gas-liquid flow situations on CTST has an important guiding meaning to industrial applications.Computational Fluid Dynamics (CFD) is used to predict the liquid flow patterns and hydraulics of commercial-scale distillation column. CFD is low cost, high efficiency, and easy to change the parameters and operational conditions of the tray, so it is an important method in research of liquid flow filed.A computational fluid dynamics model of a commercial-scaled 2600mm diameter double-pass CTST tray was developed, and CFD software was used to simulate the gas and liquid flow field. The liquid flow fields were calculated at different cases on double-pass CTST tray. The gas-liquid two phases flow field in internal of cap, and between the caps were studied at different planes, and also the phase holdup distribution on board were studied. The gas-liquid two phases flow fields were obtained on double-pass tray.The results of CFD showed that the liquid flow was uniformly on center-to-side flow, which was similar to the convergent flow, and also the recirculation zone was not exist on center-to-side flow. The liquid flow was not uniformly on side-to-center flow, the velocity was great at the field near the center of plate, and where the reflow phenomenon existed. Liquid layer height of cap area is smaller than others in the plate, and the liquid phase holdup is lower. When the fluid flow was constant, the liquid layer height was more and more thinner with the increasing of gas velocity on the double-pass tray. The clear liquid height of the CFD results were in good agreement with the results of empirical formula, and the validity of the CFD model for double-pass flow was proved. The simulation results indicated that CFD could be used as a powerful tool in improving and optimizing the tray. |
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