Numerical Simulations of Flow Field in Propylene Slurry Polymerization Reactors Based on CFD
State Key Laboratory of Polyolefins and Catalysis；Shanghai Key Laboratory of Catalysis Technology for Polyolefins, Shanghai Research Institute of Chemical Industry Co Ltd, Shanghai 200062, China
Abstract：The liquid-solid two-phase flow in a propylene slurry polymerization reactor was numerically simulated based on computational fluid dynamics model (CFD). The 5 liters reactor model with no baffle, conical bottom, and four-leaf propeller was established and the multiple reference frame (MRF), mixture multiphase fluid model and RNG k-? model were used to simulate the stirring process. The reliability of the models was verified by the cold-model experiments. The velocity and the concentration fields of the fluid in the kettle were obtained by 10% polypropylene volume concentration fraction. The results showed that the fluid in the autoclave was characterized by double circulation flow, and the axial concentration of polypropylene was distributed low in the middle and high on both sides. The radial direction appeared to be in the “lower convex”, “linear” and “W” type along with the rise of the axial position. The mixing effect was found to be the best when the stirring speed was about 1 200 r/min with the blade installation height of 0.56D(D is the diameter of the cylindrical part of the kettle),and the blade diameter 0.49D. The mixing effect appeared to be the best when the rotational speed was 1 000 r/min with the blade diameter of 0.52D and the blade installation height of 0.56D. Properly reducing the installation height of the blade in the kettle can improve the accumulation of polypropylene at the bottom of kettle to some extent.
Wu Yufan,Wang Xiugang,Mai Yongyi et al. Numerical Simulations of Flow Field in Propylene Slurry Polymerization Reactors Based on CFD[J]. 化学反应工程与工艺, 2018, 34(3): 202-212.
