Numerical Study On Flow Field In Oxidation Reactor With Chlorination Titanium Dioxide

Titanium dioxide is considered to be the world’s best performance of a white pigment,Currently,chlorination is an advanced technology of producing high-grade titanium dioxide.The production of titanium dioxide by chlorination is divided into chloride phase and oxidation stage.And the oxidation stage is the key stage.The device that is the core of the oxidation stage is the oxidation reactor.The oxidation reactor has some technical difficulties,such as gas mixed complex,the inner wall of the reactor is easy to form scar,difficult to control products.The internal structure of the oxidation reactor directly affects these problems.In the process of gas phase oxidation,in order to improve the efficiency of the oxidation process,improve the yield and quality of titanium dioxide.High temperature O2 and TiCl4 need to be fast,uniform and close mixing in the oxidation reactor.Therefore,this paper studies the internal flow field of the oxidation reactor,numerical simulation was carried out for the gas mixing in the reactor.The change trend of flow field distribution in oxidation reactor was studied,further optimize the structure of the oxidation reactor,and provide the theoretical basis for the actual industrial mass production.Mainly from the following several aspects of research:First of all,the paper introduced the use of titanium dioxide,the main production technology,the current situation of domestic and foreign production of titanium dioxide,and the research method and its significance.In this paper,FLUENT is used to simulate the gas mixture model.On this basis,the physical model of TiCl4 oxidation reaction was established by SolidWorks.The structure of oxidation reactor is very complicated,including the scar removal device and cooling device etc.In order to facilitate the research,the structure of the oxidation reactor is simplified,one of the main features and the key structure is presented,without considering other non important factors and secondary structure.Then,using the Gambit software to divide the grid,the total number of grid cells is about 500 thousand.Next,the simulation method and parameter setting of TiCl4 oxidation reaction were discussed.Through the discussion,this paper chooses Realizable k-s turbulence model and finite rate chemistry model.And the boundary conditions and other parameters are determined.Lay a solid foundation for the follow-up study.Finally,the factors that affect the oxidation reaction of TiCl4 are discussed.The flow field in different angles(300°、45°、600°、75°),different momentum ratios(1.07、0.83、0.62、0.44、0.29)and different diameter(10mm、20mm)oxidation reactors were simulated,mainly from the velocity field,temperature field,concentration field,velocity radial distribution map,TiO2 mass fraction map and other aspects of the above different factors were studied and discussed,the optimal data of the structure of the oxidation reactor is obtained:angle of 75 degrees,momentum ratio of 0.29,the diameter of 10mm for oxidation reactor are considered to best improve the quality of titanium dioxide.