Hydrodynamic Characteristics Study Of A Novel Gas-liquid Mass Transfer Cell

Distillation is one of the most important units in the chemical separation process.But the capacity of traditional cross-flow trays is usually limited by the entry way of the gas and the entrainment on the tray,and the energy consumption is large.Saving energy and reducing consumption are inevitable trends in social development.In this study,a new type of energy-saving tray with high-capacity have been designed and developed based on the centrifugation.The hydrodynamic performance of the new tray was investigated by experiment and simulation methods.The optimization design was further carried out to determine the optimal structural parameters.Firstly,an experimental study was carried out in the mass transfer cell.Air-water was used as a gas-liquid medium to measure dry plate pressure drop,wet plate pressure drop,weeping,entrainment and Murphree tray efficiency in a Plexiglas column with a diameter of 500 mm.The results showed that the wet plate pressure drop of the new tray was 70%lower than the sieve plate in the same conditions.And the entrainment rate and weeping rate remained low even under high capacity.Which proved that the new tray had excellent hydrodynamic performance and better operational flexibility.According to the actual plate structure,the hydrodynamics geometric model and mathematical model were established.After meshing the high-quality grid,the single-phase flow and gas-liquid multiphase flow simulations on the plate were performed,thus the gas-liquid two-phase velocity field,pressure field,turbulent kinetic energy and gas-liquid distribution information in the mass transfer cell were obtained.The calculated results are in good agreement with the experimental test values.It was found that the structure of the height of the overflow pipe and the position,area of the liquid outlet on the shell influenced the hydrodynamic performance of the mass transfer cell.According to the optimization experimental results,the final cell structure with better performance were obtained:the distance between the bottom of overflow pipe and blind plate is 50 mm;the distance between the outlet and the blades is 30 mm;the number of liquid phase outlets is 2;and the liquid outlets area is 1.88×10~4 mm~2 on the shell.