Hydrodynamics And Mass Transfer Performance Of A Flow-guided Trapezoidal Spray-packing Tray

In view of the current research status of tray technology and the actual demand of industrial production,a flow-guided trapezoidal spray-packing tray,referred to as FTS-PT,was developed by combining flow-guided holes,trapezoidal caps and structured packing.In a plexiglas tower with a diameter of 500 mm and a height of 3.5 m,the dry pressure drop,wet pressure drop,clear liquid height,weeping,ertrainment and mass transfer efficiency were measured by air-water(oxygen-rich water)system at room temperature and normal pressure.The effects of the slant angle of the trapezoidal cap,the slant angle of the cap separation plate and the height of the cap bottom gap on the performance of the FTS-PT were investigated.The experimental datas of FTS-PT were compared with New VST and F1 respectively,to objectively evaluate the performance of the FTS-PT.The results showed that the slant angle of the cap had obvious effects on the pressure drop,clear liquid height,weeping,ertrainment and mass transfer efficiency of the FTS-PT.There was an intermediate value of 8°to optimize the overall performance of the Tray.The effect of the bevel angle of the cap separation plate on the performance of FTS-PT depended only on whether or not the angle was present and not on the size of angle.The height of the cap bottom gap had no effect on the dry pressure drop,but had obvious influence on wet pressure drop,clear liquid height,weeping,ertrainment and.mass transfer efficiency.There was a median value of 10 mm to optimize the overall performance of trays.By comparison,the pressure drop and entrainment rate of FTS-PT were lower than those of New VST and F1,and the weeping rate was higher than F1 but lower than New VST,and the mass transfer efficiency was slightly lower than that of New VST,which was about 20%higher than that of F1 on average.Based on the experimental datas of pressure drop for FTS-PT,the dry and wet pressure drop correlations of 8 trays were fitted,and the relative deviations between the calculated values of the fitting and the experimental datas were less than 10%.By using Bernoulli equation and the law of mass conservation,the coupling relationship between the dry pressure drop of the single mass transfer element tray and the dry pressure drop of the combined tray was derived,and the theoretical model of the dry pressure drop of the FTS-PT was obtained.The relative deviations between the calculated values of the model and the experimental datas were less than 10%.The research results showed that FTS-PT was a kind of tray with low pressure drop,large operation limits,large flux and high mass transfer efficiency,which would had a broad industrial application prospect.