炼油厂二甲苯装置吸附塔格栅用管件开裂原因分析及处置

Cause Analysis and Treatment of Cracks in Grille Fittings of Adsorption Tower for Xylene Plant in Refinery

针对二甲苯装置吸附塔格栅用管件开裂,对开裂三通进行了化学成分分析、硬度检测、拉伸试验、冲击试验、金相检验、断口宏观分析和微观分析;对未安装的管件进行了化学成分分析、硬度检测、水压试验,并抽取3个管件进行拉伸试验、冲击试验,抽取2个管件进行时效敏感性试验等。结果表明,三通开裂的主要原因是三通采用轧制态钢管制作,制作成型后没有经过正火处理,发生了严重的应变时效脆化,造成三通脆性断裂。推断已经安装的管件出现失稳断裂的可能性很小,同时鉴于已经安装的管件进行返工成本巨大,且管件操作工况缓和,又允许少量泄漏,现场决定已经安装的管件可继续使用。

For the cracking of the tee of the adsorption tower grid of the xylene plant,chemical analysis,hardness testing,tensile testing,impact testing,metallographic examination,macroscopic and microscopic analysis of the fracture were performed on the cracked tee.Chemical analysis,hardness testing and hydraulic pressure test were performed on the uninstalled pipe fittings,3 fittings were sampled for tensile testing and impact testing,and 2 fittings were taken for aging sensitivity testing.The results show the main cause for the tee cracking is that the tee is made of rolled steel pipe.The tee did not undergo normalizing treatment after making,causing brittle fracture of the tee due to severe strain aging embrittlement.It is inferred that the probability of instability fracture of the installed fittings is very low.Also,due to the huge cost of reworking of the installed fittings,the mitigated operating conditions and allowance for small leak,it was decided that the installed fittings can continue to be used on site.