C_5热二聚反应器计算流体力学研究

Study on C_5 thermal dimerization reactor by computational fluid dynamics

为了了解现有C5装置所用中空管式反应器内的流场是否为反应所期望的平推流,文中结合理论分析及计算流体力学模拟软件ANSYS CFX 14.5,采用SST湍流模型,发现其入口处存在边界层分离及再附现象。分别对在入口处增加挡板、筛板等轴向阻尼内件和旋转进料的径向阻尼内件进行CFX模拟,并引进一个与速度有关的物理量Jk来表征返混的程度。结果表明:轴向阻尼内件形式在减少返混程度作用上效果不理想,甚至有加重反混的现象,在所研究的轴向阻尼内件中,迷宫式进料效果最优。结果同时表明采用径向阻尼内件旋转进料器可以较大幅度减小反应器内返混程度。

In order to know whether the flow field in hollow tubular reactor used in the existing C5 device is plug flow which is expected by the reaction,based on the theory analysis and simulation by computational fluid dynamics （CFD）software package ANSYS CFX 14.5,and using SST model,the phenomenon of boundary layer separation and reattachment was found at the entrance of the reactor.Several axial damped internals （baffle,sieve plate）and radial damped internal （feeding screw）were added at the entrance of the reactor for CFX simulation to improve the flow condition,and a physical quantity named Jk which is related to velocity was used to show the extent of the back-mixing.The results show the performance on reducing the extent of back-mixing is not very good by adding axial damped internals,which may even aggravate the problem.Labyrinthic baffle performs best in these axial damped internals.The results also show that the extent of back-mixing can be reduced greatly by adding feeding screw.