不锈钢换热器的空蚀破坏

苯酚装置精制塔第二冷凝器投用后，管束材质先后使用过多种材料，均发生泄漏。对失效不锈钢换热管进行化学成分分析和金相分析显示材料的元素含量和组织均正常，从宏观形貌和电镜观察发现管柬内表面流体一侧出现明显的海绵蜂窝孔面，此形貌是空蚀的典型特征。通过分析换热管内物料操作压力与温度发现物料存在汽化现象，沸腾产生的气泡使得管柬局部...

Damage from Cavitation Corrosion of Stainless Steel Heat Exchangers

After the second condenser in phenol refining unit was commissioned, the condenser tubes leaked many time and were replaced with tubes of a number of different materials. The chemical composition analysis of stainless steel tubes and metallographic analysis showed that the element contents and structures were normal. The macro - morphology and scanning electron microscope （SEM） analysis found sponge honeycomb holes in the internal wall of tubes where the liquid flowed, which was typical of cavitation corrosion. The study of operating pressure and temperature of flow media in heat exchange tubes demonstrated that there was vaporization of flow media and boiling bubbles accelerated liquid flow velocity in the local superheated areas, resulting in surge and erosion of tube walls. To make matter worse, the collapse of bubbles produced micro jets and strong local impingement force, which led to the material failure from micro - bubble erosion. The cavitation damage of stainless steel heat exchange tubes can be prevented by adjustment of operating pressure and temperature to prevent liquid in the tubes from boiling and selection of CrMnN austenitic stainless steel or duplex stainless steel lined with titanium.