Abstract:

TiCl₄ oxidation reactor is the key equipment in the chloride process of TiO₂, while the scarring inside the reactor significantly affects its long-period and consistent operation. In this study, the scarring reason in the industrial reactor was firstly investigated by composition analysis, and then, by the CFD simulation of the internal flow and wall temperature distribution, which is employed in the ANSYS-Fluent software package under the circumstance of actual operating conditions. The simulation results show that the reactor wall temperature, internal flow field and other factors have a very important influence on the scarring of the reactor. The wall temperature in the hot-oxygen zone should be higher than 770℃ and that in the TiCl₄ feeding ring should be higher than 178℃, respectively, for preventing the additives of KCl and AlCl₃ depositing on the inner wall of the reactor. In order to avoid the newly generated TiO₂ to aggregate on the inner wall of the reaction zone, vortexes should be eliminated or reduced for the newly generated TiO₂ with high-activity to timely pass through the reaction zone.

Key words: numerical simulation, CFD, chloride process of titanium dioxide, oxidation, anti-scarring technology

摘要：

氯化钛白生产工艺的核心是TiCl₄氧化反应器，而内部关键部位的结疤问题显著影响其长周期稳定生产。通过对工业氯化钛白氧化反应器疤料的分析与表征，探究了氧化反应器关键位置的结疤原因，进而使用ANSYS-Fluent软件对实际运行工况条件下的氧化反应器内部流场和壁面温度进行了计算流体力学(CFD)模拟。模拟结果表明，反应器壁面温度、内部流场等因素对反应器的结疤具有十分重要的影响。提高反应器关键位置壁面温度，能够显著改善结疤现象，为防止KCl和AlCl₃添加剂的沉积，反应器热氧区和TiCl₄进料环的壁面温度应分别高于770和178℃；而为避免新生成的TiO₂在反应器内表面的聚集，应减小或消除回流区，使得新生成的TiO₂尽快通过反应区。

关键词: 数值模拟, 计算流体力学, 氯化钛白, 氧化, 防结疤技术