Separation Characteristics in a Novel Gas–Liquid Vortex Separator

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Fischer–Tropsch (FT) synthesis is an essential way to achieve the cleanliness of oil products. A novel gas–liquid vortex separator (GLVS) was put forward to use in the FT synthesis. GLVS has four symmetry vortex arms set inside the separator body. The characteristics of pressure drop and separation efficiency of the GLVS were investigated through a large-scale cold model. The influences of the inlet gas velocity and the inlet liquid concentration on the separator were analyzed. An improved weighting method to calculate the droplet separation efficiency was proposed. The experimental results indicated that the GLVS fits the aerodynamic design and can be operated stably. The dimensionless standard deviation of the pressure drop is maintained within 2%. The “roof skimmers” is not suitable for the GLVS based on visual observation and analysis of the segmental pressure drop, which exacerbates the entrainment. The improved GLVS-2 removes the roof skimmers and increases the diameter of the outlet pipe (vertical) by 0.1 m. These changes reduced the total pressure drop by about 50% compared with the GLVS-1. A model was proposed to predict the pressure drop, wherein the Eu number is 8.08. The pressure drop of the GLVS is mainly affected by the gas velocity, and the liquid concentration has less effect on the pressure drop. The Sauter mean diameter of the droplets initially entering the GLVS is 15.27 μm. It is found that the separation efficiency of the GLVS-2 is about 10% higher than that of the GLVS-1. The liquid critical concentration of the GLVS-2 is related to the gas velocity. Although the entrainment above the vortex arms formed the water bath at a high gas velocity in GLVS-2, it has a positive effect on the separation. The combination of the empirical droplet size model and equilibrium-orbit model can be used to predict the separation efficiency of GLVS-2 with an average deviation of 1.95%.