Flow Field Simulation On Double-ring Radial Flow Reactor

With the presence of platinum catalyst(aluminum or zeolite as the carrier),the dehydrogenation of long chain paraffin to mono-olefins happens in a radial flow reactor(RFR).The mono-olefins can be the material for alkyl benzene production.This paper took the reactor of paraffin dehydrogenation as the research object.The reactor is from the SINOPEC JinLing Company,which is a gas-solid double-ring RPR with two catalyst beds reformed from traditional RFR.Compared with the traditional Radial Flow Reactors(RFRs),double-ring RFRs possess advantages including lower pressure drop,shorter flow path and greater flow area.Therefore,they have high value in industrial application for large quantity flows.According to the Ergun's equation,continuity equation and the modified momentum equation,a two-dimensional hydrodynamic model was established to describe the hydrodynamic behavior in double-ring RFRs.The flow assignment parameters(T)of mass flow in the inner channel to the outer catalytic bed and inner catalytic bed were optimized by Powell method.This paper judged the assumed T function type reasonable or not by the condition that the central channel and the outer channel should have the same outlet pressure,which can validate the model reliability.Based on the established model,this paper calculated axial uniformity of gas distribution the inner and outer ring,weight hourly space velocity(WHSV)of inner and outer catalyst beds with different reactor size to balance the inner ring and outer ring.The simulated result showed that the optimized inside radium of inner catalyst bed is 0.3175?0.3195 m when the inside radium of inner catalyst bed and the other size is fixed but the radium of central channel.And the optimized outer radium of outer catalyst bed is 0.907?0.910 m,when the outer radium of outer catalyst bed and the other size is fixed but the inside radium of outer channel.The model can be used to analyze the reasonability of dehydrogenation reactor design,and it can also provide quantitative reference for the design of new double-ring RFRs.