Experimental And CFD Simulation Of 3D Printing New Metal Structured Packing

In this paper,a new type of metal structured packing（DP-1 structured packing）was fabricated by 3D metal printing technology,and the hydrodynamic and mass transfer experiments were carried out.The results show that the pressure drop and liquid holdup of DP-1 structured packing increase with the increase of F factor and spray density,and the flooding point gas velocity decreases with the increase of spray density.Compared with traditional packings,DP-1 structured packing has larger pressure drop,smaller flooding point gas velocity and smaller operation elasticity.When F factor≤0.2 m·s^-1·(kg·m^-3)^0.5,the mass transfer performance of DP-1 structured packing is higher than 750Y,when 0.2≤F factor≤0.3 m·s^-1·(kg·m^-3)^0.5,the mass transfer performance is similar to that of 750Y and 500Y,and when 0.4≤F factor≤0.7 m·s^-1·(kg·m^-3)^0.5,the mass transfer performance is similar to that of 250Y and 500Y.Under the experimental conditions,the maximum number of theoretical plates per metre of DP-1 structured packing can reach 8.It is shown that DP-1 structured packing is a new type of highly efficient structured packing suitable for low load.To further study the flow in DP-1 structured packing,this paper conducts a preliminary exploration of 3D CFD numerical simulation of DP-1 structured packing.The simulation results of gas single phase flow and gas-liquid two phase flow are in good agreement with the experimental,which shows that the calculation model is reliable.The effects of gas velocity,liquid velocity,packing structure and size on the hydrodynamic properties of DP-1structured packings were discussed by CFD.The results show that the flow of gas in the packing is mainly based on the compression-expanded jet flow,and the gas forms an S-shaped flow through the side wall of the inner wall of the packing.This flow not only increases the flow of the gas but also increases the gas-liquid turbulence degree,which is conducive to the gas-liquid mass transfer process.The liquid is still dominated by the liquid film flow along the wall in the packing channel,and the liquid film flow through the side holes of the wall will be blown into a mist flow by the gas,which strengthens the gas-liquid mass transfer process.Due to the small size of the necking area of the packing,the flow area is small,the liquid is easily clogged,and the pressure drop of the DP-1 structured packing is high.The side wall of the packing wall has the function of enhancing the mass transfer and relieving the pressure,but the pore diameter is small and the number is limited,and the diversion is not obvious,which is one of the main reasons for the high pressure drop of the DP-1 structured packing.The experimental study and CFD simulation of DP-1 structured packing show that the DP-1 structured packing has an highly efficient mass transfer structure,but its hydrodynamic performance is poor.The results of this paper can provide guidance for the optimization and industrial design of DP structured packings.