催化分馏塔顶循抽出线管道腐蚀分析及最小壁厚核算

Corrosion Analysis And Minimum Wall Thickness Calculation of Catalytic Fractionation Tower Top Circulation Pipeline

某催化裂化装置累计运行不到5年时间分馏塔顶循抽出线壁厚明显减薄,最严重处由10mm减薄至4.5mm。分析原因主要为催化分馏塔顶普遍存在的NH4Cl盐腐蚀。经过管道壁厚计算和应力分析,认为该管线壁厚减薄严重,目前已存在较大风险,需尽快更换。提出了增设顶循除盐设施的解决方案,以降低管线铵盐浓度,从根本上减缓管线腐蚀速率。

The wall thickness of the circulation outlet line at the top of the fractionation tower of a catalytic cracking unit decreased significantly during the cumulative operation of less than 5 years,and the most serious part was reduced from 10mm to 4.5mm.The main reason is considered the commonly found corrosion of ammonium chloride at the top of catalytic fractionation tower.Through wall thickness calculation and stress analysis of this pipeline,it is considered that the pipeline wall thickness is seriously reduced,and is on great risk at present,which needs to be replaced as soon as possible.The solution of adding top-circulation desalting facilities is put forward to reduce the ammonium salt concentration and fundamentally slow down the pipeline corrosion rate.