天然气最终脱硫槽筒体开裂及封头鼓包原因分析

Cause analysis of cracking and head bulges in natural gas final desulfurization tank

天然气最终脱硫槽在服役时筒体部位发生开裂并引发起火事故,利用化学分析、金相检验、力学性能测试及断口形貌分析等手段对筒体开裂和封头鼓包的原因进行了分析。分析结果表明:在设备服役过程中,筒体和封头内部发生了氢腐蚀现象,进而使得材料内部产生了孔洞,导致材料强度下降,冲击韧性变差,最终在筒体外表面萌生裂纹造成筒体开裂;封头处产生的孔洞数量少于筒体开裂处,且本身壁厚大于筒体,在筒体开裂后内部压力减小,造成封头鼓包。

A fire broke out for the reason of cylinder body cracking during the operation of a natural gas final desulfurization tank.The cracking of cylinder body and head bulge was studied by employing chemical analysis,metallographic inspection,mechanical performance testing and fracture morphology analysis.The finding suggested that hydrogen corrosion occurred inside cylinder and head during the service process of equipment and further led to holes inside material,resulting in decreased strength,poor impact toughness and cracks on the surface of cylinder.The amount of holes generated at head was lower than that at cracking area of cylinder,and the head was thicker than that of cylinder.The internal pressure decreased after the cracking of cylinder,resulting in formation of bulges at head.