FCC粗旋与顶旋连接方式对顶旋气量分配的影响

IMPACT OF LINKAGE TYPE BETWEEN PRIMARY AND SECONDARY CYCLONE ON OIL-GAS DISTRIBUTION IN FCC

采用数值模拟方法对闭式直连的FCC两级旋风分离系统内的三维流场进行了系统研究。首先,通过选用不同湍流模型对单个旋风分离器内的强旋流动进行数值模拟计算,并与实验数据对比确立了可以用于两级旋风分离器研究的模型和计算方法。随后,采用已确立的模型和计算方法考察了不同连接方式对两级旋风分离系统内流动的影响,得到了不同直连方式下粗旋排出油气在左、右顶旋间的分配比例。以两顶旋间油气量合理分配及高效分离所需正常入口气速为考察基准,确定了既可以平均分配进入左、右顶旋的油气量,又能有效利用粗旋出口油气的旋转能量减小系统压降的合理连接方式。

Three-dimensional gas flow field in close-coupled cyclone system of FCC was numerically simulated.Firstly,the strongly swirling flow in a single cyclone was calculated with different turbulence models.By comparing simulation results with experimental measurements,the turbulent model and calculation method,which could be used to investigate close-coupled cyclone system of FCC,were established.Secondly,the simulation of cyclone systems with different linkage types was carried out,and the effects of linkage type on oil-gas flowing into the second cyclones were investigated.Subsequently,the distribution of oil-gas between left and right secondary cyclone as well as the overall pressure drop were obtained.The results showed that reasonable connection type in close-coupled cyclone system of FCC was not only able to equally distribute oil-gas,but also greatly to reduce system pressure drop by effectively using rotation energy of oil-gas flowing out of the primary cyclone.