Hydrodynamics And Mass Transfer Performance Of A Flow-guided Vertical Jet Composite Tray

Column occupies an important position in the chemical separation field because of its advantages of simple structure,low cost,wide adaptability range of liquid-gas ratio,and convenient to meet special requirements in the chemical process.With the development of the times,increasing efficiency and saving energy has become the main line of the development of chemical enterprises,so it is of great significance to develop high-efficiency low-pressure drop tray and study its hydromechanical properties.Facing the production practice in the field of chemical separation,this paper aims to solve the contradiction between high purity and high energy consumption.A flow-guided vertical jet composite tray(FVJT)composed of guide hole、bubble promoter and vertical cap is designed,which is high efficient and has low pressure drop.The hydrodynamics performance and mass transfer performance of FVJT tray were measured in a transparent plexiglass column with diameter of 800 mm and height of 3.5 m by air-water system,including dry and wet tray pressure drop,clear liquid layer height,entrainment,weeping and mass transfer efficiency.The quality of eight FVJT trays were explored by changing the opening rate of tray,tilt angle of vertical cap and length of rectangular hole external baffle plate.Meanwhile,the performance of FVJT tray was compared with New VST and F1 valve tray with the same opening rate,in order to reasonably judge and analyze the performance of FVJT trays.The results show that with the increase of tray opening rate,tray pressure drop also increases,while the mass transfer efficiency decreases,which is not conducive to mass transfer.The tilting cap and the external baffle with rectangular hole can increase the pressure drop of tray slightly and improve the mass transfer efficiency significantly.The mass transfer efficiency is the highest when the tilting angle of vertical cap is 6°.The change of baffle length has no obvious effect on the mass transfer efficiency.By comparison,the dry tray pressure drop of FVJT is 10 percent to 20 percent lower than New VST at the same gas velocity,30% lower than that of F1 valve on average,and 16% higher than the mass transfer efficiency.The classical model based on the resistance coefficient and the summation model were used to carry out the correlation fitting of the dry and wet tray pressure drop of FVJT,and the relative deviation of all fitting results was basically less than 6%.Combined with the structure of FVJT,the pressure drop model of FVJT is deduced from the fluid flow theory,which is used to optimize the further design of tray.The flow-guided vertical jet composite tray in this study meets the requirements of industrial design and is expected to coincide the subsistent demand of high efficiency,high operating upper limit and low pressure drop in the distillation separation process.It has broad application prospects.