除焦粉微旋流器内流场的模拟研究

Simulation study on internal flow field of mini hydrocyclone of coke powders

油品携带焦粉对石油化工生产装置的高效、长周期运转影响较大,为了考察除焦粉微旋流分离器内液体、固体的流动特性,采用CFD研究方法对该过程进行了模拟研究。利用FLUENT 6.3.26软件,在连续相采用Reynolds应力模型、分散相采用离散相模型,用SIMPLE压力-速度修正算法求解,得到了微旋流分离器内压力、切向速度、轴向速度分布及与实验结果相近的模拟级效率曲线。结果表明,在压力降为0.22 MPa,进口速度为9.26m/s,分流比为8%的进口条件下,级效率d50模拟值约为6.3μm,10μm以上微粒去除率达到90%以上,该微旋流器可应用于油品净化过程。模拟预测的切割粒径与实验基本相符,可指导旋流分离器的优化设计,但分级精度比实验值高,粒径小的时候,效率偏低,粒径大的时候,效率偏高,模型还有待进一步优化。

The coke powder carry-over with product oil has a great impact on high-efficiency long-term operation of petrochemical process units. To have a detailed study on the flow dynamics of liquids and solids in coke particle micro hydrocyclone, CFC has been applied in the simulation study. FLUENT 6.3.26 software, the Reynolds stress model for continuous phase and SIMPLE pressure-velocity correction discrete phase model for disperse phase have been applied to get the internal pressure, tangent and axial velocity distributions and simulated efficiency curve close to demonstration results. The simulation results show that, under the condi- tions of 0.22 MPa pressure drop, 9.26 m/s inlet flow velocity and 8% shunt percentage, the removal rate of simulated 6.3 μm, 10 μm and larger particles of d50 grade efficiency is over 90%. This mini cycle hydrocy- clone can be used for purification of oil products. The simulated particle sizes are basically consistent with those of demonstration tests, which can be applied for reference in optimization design of mini hydrocyclone. The efficiency is lower for smaller grade particle size and higher for larger grade particle size. The model has to be further optimized.