固定床反应器甲醇制烯烃反应过程的CFD模拟

摘要

A one-dimensional quasi-homogeneous reactor model was established to simulate methanol-to-olefin processes in fixed bed reactors based on industrial MTO production. A lumped kinetic model with SAPO-34 catalyst was adopted. A porous medium transfer model and Spalart-Allmaras turbulence model were chosen during steady simulation in FLUENT software. The distribution of temperature and concentration fields in the reaction tube were obtained during simulation, and the applicability of the model was verified by comparing with literature data. The effects of operating parameters (feed temperature, operating pressure and feed ratio of water to methanol) on methanol conversion, olefin selectivity and molar ratio of ethylene to propylene were studied. The simulation investigated the distribution principles of temperature, composition, selectivity and other parameters along the reaction tube. The results show that these parameters affect methanol conversion and product selectivity. The optimum parameters are determined, which are feed temperature 723 ~ 773 K, operating pressure 0.3 ~ 0.4 MPa and feed ratio of water to methanol<0.5.These results are helpful for MTO research and applications.%基于工业甲醇制烯烃反应过程，建立固定床反应器一维拟均相模型，采用集总动力学模型及FLUENT中的多孔介质传递模型、S-A单方程湍流模型进行反应过程的稳态模拟，在验证模型可靠性的基础上，考察操作参数(进料温度、操作压力、进料水醇比)对甲醇转化率、产物选择性和烯烃摩尔比的影响，得到温度、组成、选择性等参数沿反应管轴向分布的规律。结果表明：操作条件影响甲醇转化率和产物选择性，较合适的操作条件是进料温度723~773 K、操作压力0.3~0.4 MPa、水醇比低于0.5。该研究结果对于甲醇固定床反应过程的研究及工业操作有良好的指导意义。