Simulation of circulating flow in an annular channel for production of titanium pigment through the chloride process

Abstract

The mixing uniformity of the feeding gas TiCl4 and oxygen is the main characteristic of an oxidation reactor, which is a key equipment in titanium pigment production. Therefore, the fluid dynamic behavior of the feeding gas (TiCl4) in an annular channel, which affects the mixing uniformity, should be investigated thoroughly. According to the geometry of the annular channel, a realizable three-dimensional κ–e turbulence model was developed in this study. To verify the model, the calculated results were compared with data published in the literature. The errors were 1.73% and 3.33% for radii of 175 and 215 mm, respectively, thereby validating the model. Using the developed model, the flow characteristics of TiCl4 in an oxidation reactor with a tangential inlet were investigated. The results showed that, with an increase in the circumferential angle of the annular channel, the velocity first increased and then decreased, with a maximum value at a circumferential angle of 60°. The inlet Reynolds numbers and hole density of the jet ring had slight effects on the dimensionless pressure distribution in the annular channel. With an increase in the flow flux or a decrease in the diameter of the inlet pipe, the pressure curve became smoother, indicating that a homogeneous distribution of the feeding gas could be obtained.