| Gas distributor is often designed at the bottom of the regenerator of FCCU(fluid catalytic cracking unit),used to distribute gas for maintaining the particle fluidizing,and provide the oxygen for coke burning reaction.However,in practical application,the gas distributor often has a problem of erosion,which not only reduces the combustion efficiency of the coke but also reduces the activity of the regenerated catalyst.The gas distribution performance and erosion of the gas distributor are directly related to its internal flow field characteristics.Therefore,it is necessary to study the flow field characteristics in the gas distributor.In this study,the gas flow field of the gas distributor and the gas-solid flow field near the branch tube were investigated by numerical simulation.Further,the flow phenomenon of the gas-solid fluid near the branch tube was investigated by experiment.The causes of the erosion of the gas distributor were analyzed and the corresponding antiwear suggestions were put forward based on the simulation results and the experimental results.The main conclusions of this study were as follows:The gas axial velocity along the branch tube decreases gradually while the static pressure increases gradually,and the gas velocity in each nozzle is quite different.Redesigning the diameter of the branch tubes and the number of nozzles helps to improve the air distribution performance.There exists an obvious uneven flow at the inlet region resulting in nozzle gas velocity varying seriously.The pressure distribution is nonuniform along the branch tube,which may cause entraining catalyst into nozzle at this region.Particles driven by the gas impact the branch tube wall with high speed,which may lead to erosion heavily. |
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