Computational fluid dynamic simulation of gas-liquid flow in rotating packed bed:A review

The rotating packed bed(RPB)has been widely used in gas-liquid flow systems as a process intensification device,exhibiting excellent mass transfer enhancement characteristics.However,the complex internal structure and the high-speed rotation of the rotor in RPB bring significant challenges to study the intensification mechanism by experiment methods.In the past two decades,Computational fluid dynamics(CFD)has been gradually applied to simulate the hydrodynamics and mass transfer characteristics in RPB and instruct the reactor design.This article covers the development of the CFD simulation of gasliquid flow in RPB.Firstly,the improvement of the simulation method in the aspect of mathematical models,geometric models,and solving methods is introduced.Secondly,new progress of CFD simulation about hydrodynamic and mass transfer characteristics in RPB is reviewed,including pressure drop,velocity distribution,flow pattern,and concentration distribution,etc.Some new phenomena such as the end effect area with the maximum turbulent have been revealed by this works.In addition,the exploration of developing new reactor structures by CFD simulation is introduced and it is proved that such new structures are competitive to different applications.The defects of current research and future development directions are also discussed at last.

NO_(x) removal by non-thermal plasma reduction:experimental and theoretical investigations

Green and efficient NO_(x)removal at low temperature is still desired.NO_(x)removal via non-thermal plasma(NTP)reduction is one of such technique.This work presents the experimental and theoretical study on the NO_(x)removal via NTP reduction(NTPRD)in dielectric barrier discharge reactor(DBD).The effect of O_(2)molar fraction on NO_(x)species in the outlet of DBD,and effects of NH_(3)/NO_(x)molar ratio and discharge power of DBD on NO_(x)removal efficiency are investigated.Results indicate that anaerobic condition and higher discharge power is beneficial to direct removal of NO_(x),and the NO_(x),removal efficiency can be up to 98.5%under the optimal operating conditions.It is also found that adding NH_(3)is favorable for the reduction of NO_(x),to N_(2)at lower discharge power.In addition,the NO_(x)removal mechanism and energy consumption analysis for the NTPRD process are also studied.It is found that the reduced active species(N^(+),N^(-),N^(+),N_(2)^(*),NH_(2)^(+),etc.)generated in the NTPRD process play important roles for the reduction of NO_(x),to N_(2).Our work paves a novel pathway for NO_(x)removal from anaerobic gas in industrial application.