二硝基甲苯加氢反应器的数值模拟与优化

发布时间：2018-06-23 23:10

本文选题：自吸式反应器 + 计算流体力学　；参考：《青岛科技大学》2017年硕士论文

【摘要】：自吸式反应器因无需外加压缩机,具有能耗小等优势,在加氢等工业中应用越来越广泛。近年来通过数值模拟方法研究流体流动和混合特性具有显著的优势,本文采用CFD数值模拟方法对自吸式二硝基甲苯加氢反应釜进行优化研究,为反应器的设计与优化提供重要参考。主要研究内容和结果如下:(1)本文对不同的湍流模型和其他CFD模型参数进行应用,采用模拟结果与实验数据对比的方法来验证它们的准确性。通过对Standard k-ε湍流模型、RNG k-ε湍流模型和Realizable k-ε湍流模型的验证,最后选择了RNG k-ε湍流模型来进行自吸反应釜的湍流计算。通过对气液、固液、液液两相模拟方法的验证,最后确定了两相模拟的适用模型为:稳态计算,使用多重参考系法模拟桨叶区的旋转,压力和速度的耦合采用SIMPLE算法,采用二阶迎风差分格式,两相模型为欧拉模型,两相的曳力模型选用Gidaspow模型。(2)本文对现有的实验反应器进行建模,采用CFD模型对其进行模拟研究,为反应器的优化设计提供依据。主要从自吸桨叶类型、桨叶直径、桨叶距釜底距离,筒体结构,双层桨叶组合和进料位置等方面进行优化,得到反应器优化方案:自吸桨叶应该采用空心桨叶;自吸桨叶直径在(0.23~0.3)T范围内;筒体应该使用椭圆结构釜底;对于双层桨叶,下层桨叶使用PBTU 45桨,桨叶间距L在(1~1.5)D范围内,下层桨叶直径越大对气体自吸越有利但不能大于上层桨叶的直径。通过对反应器内的固液两相和液液两相进行非稳态模拟,确定催化剂和DNT的最佳进料位置:催化剂颗粒的最佳进料位置在液面下方,DNT的最佳进料位置在上层桨叶下方。(3)本文采用几何相似的放大方法以及自吸桨叶端线速度相等的放大准则,将优化后的反应器放大至10 m3。通过CFD建立了包含换热板的反应器模型,模拟了反应器内气液、固液和液液两相的混合性能。模拟结果验证了放大过程的可靠性。
[Abstract]:Self-priming reactor is widely used in hydrogenation industry because of its low energy consumption and no external compressor. In recent years, numerical simulation method is used to study fluid flow and mixing characteristics. CFD numerical simulation method is used to optimize the self-priming dinitrotoluene hydrogenation reactor. It provides an important reference for the design and optimization of the reactor. The main contents and results are as follows: (1) in this paper, different turbulence models and other CFD model parameters are applied to verify their accuracy by comparing simulation results with experimental data. The RNG k- 蔚 turbulence model and the realizable k- 蔚 turbulence model are verified by the Standard k- 蔚 turbulence model. Finally, the RNG k- 蔚 turbulence model is selected to calculate the turbulence of the autogenous reactor. Through the verification of gas-liquid, solid-liquid and liquid-liquid two-phase simulation methods, the suitable model of two-phase simulation is determined as follows: steady-state calculation, simulation of rotor blade rotation using multi-reference system method, and simple algorithm for the coupling of pressure and velocity. The second order upwind difference scheme is used, the two-phase model is Euler model, and the two-phase drag model is Gidaspow model. (2) in this paper, the existing experimental reactor is modeled, and the CFD model is used to simulate it. It provides the basis for the optimal design of the reactor. From the aspects of self-priming blade type, blade diameter, blade distance from the bottom of the kettle, barrel structure, double-layer blade combination and feed position, the optimization scheme of the reactor is obtained: the self-priming blade should be hollow blade; The diameter of the self-priming blade is in the range of (0.230.3T) T; the cylinder should use the bottom of the kettle with an elliptical structure; for the bilayer blade, the lower blade uses PBTU 45 propeller, and the blade spacing L is in the range of (11.5D) D. The larger the lower blade diameter is, the more favorable the gas self-priming is, but not larger than the upper blade diameter. The unsteady state simulation of solid-liquid two-phase and liquid-liquid two-phase in the reactor was carried out. The optimal feed position of catalyst and DNT is determined: the best feed position of catalyst particle is below the liquid level and the optimal feed position of DNT is below the upper blade. (3) in this paper, the geometric similarity amplification method and the speed of self-priming blade end line are adopted. The magnification criterion of equal degree, The optimized reactor was amplified to 10 m3. A reactor model containing heat exchanger was established by CFD, and the mixing performance of gas-liquid, solid-liquid and liquid-liquid phases in the reactor was simulated. The simulation results verify the reliability of the amplification process.
【学位授予单位】：青岛科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ246;TQ052

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