加氢裂化高压空冷器出口弯头腐蚀原因分析及防护  

Cause Analysis and Protection of Outlet Elbow Corrosion of Hydrocracking High Pressure Air Cooler

作　　者：崔轲龙[1] 曹然 靖迎涛 张立斌[1] CUI Ke-long;CAO Ran;JING Ying-tao;ZHANG Li-bin(CNPC Research Institute of Dushanzi Petrochemical Company,Dushanzi 833699,China;CNPC Refinery I of Dushanzi Petrochemical Company,Dushanzi 833699,China)

机构地区：[1]中国石油天然气股份有限公司独山子石化分公司研究院,新疆独山子833699 [2]中国石油天然气股份有限公司独山子石化分公司炼油一部,新疆独山子833699

出　　处：《全面腐蚀控制》2023年第9期14-20,共7页Total Corrosion Control

摘　　要：针对加氢裂化装置高压空冷器出口弯头腐蚀减薄问题,对减薄弯头采用宏观观察、超声波测厚、化学成分分析、金相检验、扫描电镜及能谱分析,采用ANSYS Fluent软件的DPM模型对高压空冷器出口管道进行加速冲蚀模拟,流体惯性及局部管线出现旋转流从而对弯头造成冲蚀,同时对工艺参数进行分析,NH4HS浓度长期保持在4%左右,已超碳钢对NH4HS浓度为2%的耐受极限,随着原料油硫含量的上升,在NH4HS浓度长期保持在4%的情况下,当循环氢H_(2)S含量0.5%(体积分数)上升至1.5%(体积分数),腐蚀速率预测将增加约0.4mm/a。提出在低分气脱硫塔不超负荷的前提下(脱后低分气流量≤9500Nm3/h),维持高的排废氢量,控制循环氢中H_(2)S含量≤1.5%(体积分数),以及针对目前循环氢H2S含量高的情况,应采取循环氢系统脱硫措施,有效减缓系统腐蚀。In view of the corrosion thinning problem of the outlet elbow of the high-pressure air cooler of the hydrocracking unit,the thinning elbow is analyzed by macro observation,ultrasonic thickness measurement,chemical composition analysis,metallographic examination,scanning electron microscope and energy spectrum analysis,and the DPM model of ANSYS FLUENT software is used to simulate the accelerated erosion of the outlet pipe of the high-pressure air cooler.The fluid inertia and rotatingflow in local pipelines cause erosion of the elbow,and the process parameters are analyzed,The nh4hs concentration has been kept at about 4% for a long time,and the tolerance limit of ultra-carbon steel to nh4hs concentration is 2%.With the increase of sulfur content in feed oil and the nh4hs concentration kept at 4% for a long time,when the H_(2)S content of circulating hydrogen increases from 0.5%(volume fraction)to 1.5%(volume fraction),the corrosion rate is predicted to increase by about 0.4mm/a.It is proposed that on the premise of no overload of the low separation gas desulfurization tower(low separation gasflow after removal≤9500nm^(3)/h),maintain a high amount of waste hydrogen,control the H_(2)S content in the circulating hydrogen≤1.5%(volume fraction),and take desulfurization measures of the circulating hydrogen system to effectively slow down the corrosion of the system.

关 键 词：加氢裂化 高压空冷 硫氢化铵 冲蚀 H_(2)S分压 

分 类 号：TE986[石油与天然气工程—石油机械设备]