CO_2汽提塔改造后免除水压试验问题的探讨

Discussion of CO_2 stripping column exempting from hydrostatical testing after modification

从水压试验的目的入手,对改造后不进行耐压试验的CO2汽提塔的结构应力、焊接工艺、无损检测和气密性试验等方面进行了研究,并通过基于风险的检验技术(RBI)分析了CO2汽提塔主要的损伤机理、失效可能性、失效后果和风险等级。研究结果表明,改造后的CO2汽提塔的结构强度和密封性满足使用要求;其主要损伤机理为应力腐蚀开裂、外部损伤和腐蚀减薄,但失效可能性很小,为1级,后果为B级,风险水平为低风险,根据主要的损伤机理和风险等级,有针对性的给出了降低风险的措施和建议。

The purpose of hydrostatical testing is to check the integral structural strength and leak tightness of pressure vessel under overload condition,so stress analysis,alternative welding procedure,appropriate NDE and gas-tight test according to these two purposes were carried out for CO2 stripping column without hydrostatical testing after rebuilding.Risk based inspection（RBI）was also performed to analyze the main damage mechanisms,failure likelihood,consequences and risk level of CO2 stripping column,which results indicated that：strength and leak tightness of CO2 stripping column can meet the requirements of operation;the main damage mechanism are stress corrosion,external damage and thinning,the likelihood of failure is 1 level,consequence is B level,risk level is low,some methods and suggestions to reduce risk are given based on the analysis at the meantime.