加工海洋高酸原油减压塔填料的腐蚀与防护

论述了某公司加工海洋高酸原油常减压装置减压塔填料的腐蚀问题,分析表明填料腐蚀原因是:高温环烷酸腐蚀、填料冷加工变形引起材质劣化、氯化物产生的晶间腐蚀和应力腐蚀、高温缓蚀剂的注入量不足、流体诱发振动和腐蚀疲劳。提出了减轻填料腐蚀,延长寿命的具体措施:(1)第Ⅴ,Ⅵ,Ⅶ段填料材质从316L升级为317L材质填料,并对新填料的材质进行检验分析以保证填料的材质符合要求;(2)增加材料的厚度,由原来的0.2 mm增加到0.25~0.3 mm;(3)开好电脱盐装置,降低脱后原油的盐含量;(4)增加第Ⅴ,Ⅵ,Ⅶ段填料高温缓蚀剂的有效注入量;(5)在减二中、减二线、减三线、减四线、减五线增加腐蚀在线监测探针或挂片腐蚀探针,监测侧线油的腐蚀率。

Corrosion and Protection of Packings in Vacuum Distillation Tower in Processing Marine High-TAN Crude Oils

The corrosions of packings in the vacuum tower of atmospheric - vacuum distillation unit processing marine high - TAN cmde oils in a company are discussed. The analysis shows that the corrosion causes were mainly the napthenic acid corrosion, material deterioration of packings because of deformation in cold processing and stress corrosion intergranular corrosion by chlorides, vibration and corrosion fatigue induced by fluid. The specific measures are proposed for extending the service life ： （ 1 ） the material of packings in the first V, VI, VX sections are upgraded from 316L to 317L, and the new packing material is inspected to ensure it meets the quality requirement ; （2） the thickness of packings is increased from 0.2 mm to 0.25 mm - 0.3 mm; （3） the electro- static desalting unit is properly operated to reduce the salt in the desalted crude oil; （4） the dosage of high - temperature corrosion inhibitor is increased for the packings in the V, VI, Ⅶ sections ; （ 5 ） the on - line corrosion monitoring probes or corrosion coupon probes are installed for vacuum intermedium side stream, vacuum 2nd side stream, vacuum 3rd side stream, vacuum 4th side stream and vacuum 5th side stream so as to monitor the corrosion by side stream oils.