摘要
介绍了D公司连续重整装置预加氢进料换热器E3001E管束腐蚀失效状况,并结合管束内部介质运行情况、介质腐蚀性生成等,对腐蚀失效原因进行了分析。分析结果发现,因操作失误导致流体温度低至氯化铵析出产生沉积,固态的NH4Cl一旦从含有NH3和HCl的流体中析出,NH4Cl与水反应形成酸性腐蚀环境,再加上介质流速快(甚至是涡流)造成的冲刷腐蚀,是腐蚀失效的主要原因。同时通过对比分析发现,NH4Cl的沉积等是因为操作工艺的改动导致的。因此采取了停止在E3001A/B或E3001C/D出口注水,保持E3001E入口温度为155℃,出口温度为109℃(设计要求的);加强工艺检测,严格控制反应进料的硫、氯、氮含量,以减少腐蚀介质的产生;在R3001出口与E3001A/B/C/D/E之间加一个脱氯罐有效地去除反应产物中的Cl-,以减少氯化铵的生成等改进措施。上述措施使换热器运行良好,再未出现腐蚀症状。
The corrosion failure of feed exchanger（E3001E） tubes of a CCR pre-hydrotreater was introduced.The causes of corrosion failure were analyzed based upon the operating condition of internal media in the tubes and corrosivity of media,etc.The results of analysis show that the major causes of the failure were the fluid temperature lower than eduction temperature of ammonia chloride which led to deposition due to operation failure.Once the solid NH4Cl was educed from fluid containing NH3 and HCl,NH4Cl would react with water and the acidic corrosive environment was formed.In addition,impingement corrosion from rapid medium flow velocity（or even vortex） also contributed to corrosion failure.The comparison also found that the deposition of NH4Cl was caused by the fluctuation of operating process conditions.To solve these problems,water injection was stopped at the outlet of E3001A/B or E3001C/D,and the inlet and outlet temperature of E3001 was maintained at 155 ℃ and 109 ℃（design） respectively.The process testing was strengthened to strictly control the sulfur,chlorine and ammonia in the reactor feed so as to minimize the formation of corrosive media.A chlorine removal tank was provided between outlet of R3001 and E3001A/B/C/D/E to effectively remove Cl-in the reaction product so as to reduce the formation of ammonia chloride.The implementation of above measures has maintained a good operation of the heat exchangers and no corrosion has ever occurred.
出处
《石油化工腐蚀与防护》
CAS
2012年第2期31-33,共3页
Corrosion & Protection In Petrochemical Industry
关键词
连续重整
预加氢进料换热器
冲刷
腐蚀
CCR
heat exchanger of pre-hydrotreating
impingement
corrosion
