物料流动对环氧乙烷解析塔磨损腐蚀的影响

Effect of the Flow to the Erosion-Corrosion of the EO Stripper Inwall

环氧乙烷解析塔是由环氧乙烷制备乙二醇的重要设备。在运行中其下塔靠近液体入口和出口处附近的内壁面上出现局部减薄、坑点及穿孔,严重影响了设备的安全服役。应用计算流体力学(CFD)方法对其中1块塔板上的流场进行分析,研究内部流场对壁面腐蚀的影响。结果表明,预测的腐蚀位置和区域与实际基本相符。研究发现,随着液速的增大,入口和出口附近的壁面切应力都增大,腐蚀加重;而随着气速增大,入口附近壁面切应力减小,腐蚀减轻。在保持流量不变的情况下,通过增大入口面积降低液速来调整流场分布可以抑制腐蚀和破坏。

The epoxy ethane （EO） stripper is important equipment which could make epoxy ethane into ethylene alcohol in the petrochemical industry. Widely thin area,even dotted pitting and holes were found on the inwall near the liquid entrance and exit. Those would give rise to bad influences to the safe service of the equipment. Computational fluid dynamics （CFD） methods were used to simulate the flow field of a tray,in order to study the effect of flow to the corrosion. The results demonstrated that the corrosion area was consistent with the fact. In addition, with the liq- uid entrance speed increased, the wall shear stress near entrance and exit increase, the corrosion would aggravate. On the contrary,with the gas speed increased, the wall shear stress near the entrance increase,the corrosion would mitigate. So,the Speed of liquid would be reduced using expanding the entrance area under the constant flux of liquid,and then the corrosion damage would be controlled.