乙烯裂解炉管开裂原因分析

Analysis of Causes of Ethylene Cracker Tubes

利用失效分析的方法 ,分析了 2号乙烯柴油裂解炉炉管开裂的原因 ,结果表明 :炉管开裂的原因是由于管材成分中Nb含量偏低、易引起渗碳 ,使碳化物沿晶界大量析出 ;介质中Cl,S ,Ca的存在 ,使管内壁产生点蚀和高温硫化物的腐蚀 ,破坏了管内氧化膜 ;在各种应力、特别是开停工引起的热冲击的综合作用下 ,造成炉管沿晶开裂。

The causes of cracking of No. 2 ethylene cracker tubes are analyzed by failure analysis method. The analysis shows that the cracking of the tubes is the result of low Nb content in tube material which leads to carburization and eduction of a large amount of carbides along the crystal boundary, the damage of oxidized film of the internal wall of the tubes due to the pitting and high-temperature sulfur corrosion in the presence of Cl, S, and Ca and crystal boundary cracking under the impact of stress and thermal impingement during start-up.