制氢转化炉加强接头渗碳检测分析

Carburization detection analysis of the reinforced joint of hydrogen reformer furnace

针对某石化企业制氢转化炉服役13年的加强接头,采用渗碳检测仪进行渗碳程度检测,选取典型加强接头试样试验室解剖,开展低倍酸蚀试验、金相观察/微区EDS能谱分析和维氏硬度试验,结合制氢转化炉服役工况开展了分析讨论。结果表明:186件加强接头均呈现不同程度渗碳,其中约20%的加强接头渗碳层厚度超过壁厚60%,发生严重渗碳,约63%的加强接头渗碳层厚度约占壁厚的30%~60%,为中度渗碳,约17%的加强接头渗碳层厚度占壁厚比例不超过30%,为轻度渗碳;严重渗碳的加强接头在炉膛中的分布呈局部聚集特征;加强接头渗碳程度与该部位出口温度相关,出口温度较高区域的加强接头渗碳程度较严重,反之较轻微;加强接头内壁发生渗碳,内壁渗碳区和外壁未渗碳区硬度值(HV10)分别为280~340和150~180。并讨论了制氢转化炉加强接头渗碳问题,对其安全使用提出建议。

For the reinforced joint of a hydrogen reformer furnace being put into service for 13 years,the carburization detector was used for carburization detection,the specimens of typical reinforced joints were selected for laboratory dissection,acid corrosion test,microstructure observation/microzone EDS energy spectrum analysis and Vickers hardness test were carried out,and analysis and discussion were conducted in combination with the operating conditions of the hydrogen reformer furnace.The results show that all the 186 reinforced joints show different degrees of carbonization,about 20%of the reinforced joints are severely carburized,the thickness of the carbonization layer exceeds 60%of the wall thickness;while 63%of the reinforced joints are moderately carburized,the thickness of the carburization layer accounts for about 30%~60%of the wall thickness;about 17%of the reinforced joints are slightly carburized,the thickness of the carburization layer accounts for not more than 30%of the wall thickness.The distribution of the severely carburized reinforced joints in the furnace shows local aggregation.The carburization degree of the reinforced joints is related to the outlet temperature,the carburization degree of the reinforced joint with higher outlet temperature is serious,and vice versa.Carburization occurred on the inner wall of the reinforced joint,and the hardness values of the carburization area on the inner wall and the non-carburization area on outer wall are approximately 280~340HV10 and 150~180HV10,respectively.The problem of carburization of the reinforced joint of hydrogen reformer furnace was discussed and suggestions were given for its safe use.