硫回收单元酸性水汽提塔腐蚀与防护探讨  

Discussion on corrosion and protection of sour water stripper in the sulphur recovery unit

作　　者：苏国庆 李彦 张建文[1] 张志军 SU Guoqing;LI Yan;ZHANG Jianwen;ZHANG Zhijun(School of Mechanical and Electrical Engineering,Beijing University of Chemical Technology,Beijing 100029,China;National Energy Group Ningxia Coal Industry Co.,Ltd.,Coal to Oil Branch,Yinchuan 750411,China)

机构地区：[1]北京化工大学机电工程学院,北京100029 [2]国家能源集团宁夏煤业有限责任公司煤制油分公司,银川750411

出　　处：《压力容器》2025年第1期69-77,共9页Pressure Vessel Technology

基　　金：国家重点研发计划项目(2021YFB3301100);北京化工大学交叉学科项目(XK2023-07)。

摘　　要：针对某公司硫回收单元酸性水汽提塔在运行期间频繁出现腐蚀穿孔导致泄漏的问题,大修期间对该汽提塔开展详细检查和分析。检查发现塔内被一层蓝色的腐蚀产物覆盖,除塔壁外,降液管、防冲板、塔盘等部件均发生了严重腐蚀,对失效样品进行宏观形貌、微观结构和物相组成分析。结果表明,腐蚀表面遍布具有流线形轮廓的腐蚀凹坑,还发现多个直径约为0.5 mm的小孔。在腐蚀表面检测到大量非金属元素,其中,N元素含量超过30%;确定腐蚀产物的主要组成为Fe_(4)[Fe(CN)_(6)]_(3)和FeS。塔内发生的腐蚀类型为电化学腐蚀和流动加速腐蚀,其中,进料中的H_(2)S,HCN,HCOOH等组分引起的电化学腐蚀是汽提塔失效的重要因素,高速的气液两相流对过流表面的剧烈冲刷是失效的决定性因素。采取降低汽提塔运行负荷、加强汽提塔进料稳定性、升级关键部位材质等措施,可以降低汽提塔的腐蚀风险,保障装置的安全平稳运行。Facing the problem of frequent corrosion perforation leaks occurred in the sour water stripper of a company's sulphur recovery unit during operation,a detailed inspection was carried out during the overhaul.It was found that the inner surface of the stripper was covered by a layer of blue corrosion products,and in addition to the tower wall,serious corrosion had occurred in the components such as the drop tube,anti-punching plate and tower disc.The macro-morphological,micro-structural and physical composition analysis of the failed sample were carried out.The results show that the corroded surface is strewn with corrosion pits with streamlined contours,and several small holes with a diameter of about 0.5 mm are found.A large number of non-metallic elements are detected on the corroded surface,with more than 30%of nitrogen element.The main composition of the corrosion products is Fe_(4)[Fe(CN)_(6)]_(3) and FeS.The type of corrosion occurring in the stripper is electrochemical corrosion and flow-accelerated corrosion.The electrochemical corrosion caused by H_(2)S,HCN,HCOOH and other components in the feed is an important causative factor for failure of the stripper.The high velocity gas-liquid two phase flow is a decisive factor for failure due to the violent erosion of the overflow surface.Measures such as reducing the operating load of the stripper,strengthening the stability of the feed and upgrading the materials of key parts can reduce the corrosion risk of the stripper and ensure the safe and smooth operation of the plant.

关 键 词：酸性水汽提塔 泄漏 腐蚀分析 腐蚀防护 

分 类 号：TH142[一般工业技术—材料科学与工程] TQ053.5[机械工程—机械制造及自动化] TG174.1[化学工程]