加氢裂化装置高压空冷器的阻垢与防腐

Scale Inhibition and Anticorrosion of High Pressure Air Cooler in Hydrocracking Unit

加氢裂化反应后的馏出物(油气)经过高压空冷器冷却,当温度降低达到露点条件时,在露点及其延长区产生了NH4ClNH4HS铵盐析出结垢和H2S+H2O的酸性腐蚀。NH4Cl-NH4HS铵盐析出在空冷器管束内形成垢物,使系统压降上升,物料流动阻力增大,易造成管束堵塞;H2S+H2O的酸性腐蚀会使空冷器管束减薄穿孔。采用在加氢裂化高压空冷器前注入阻垢缓蚀剂的阻垢与防腐措施,以抑制高压空冷器管束的结垢堵塞和管束的酸性腐蚀。经过注入阻垢缓蚀剂后,高压分离器脱除的冷凝酸性水中铁离子含量均小于3mg/L,达到了《中国石油炼化企业腐蚀监测管理办法》的要求,高压空冷器的压差值从0.3MPa降到0.1MPa,表明空冷器管束内无结垢无堵塞现象,使加氢裂化装置的高压空冷器的设备腐蚀和管束的结垢堵塞得到了有效控制,保证了加氢裂化装置的安全、平稳、长周期运行。

The distillate(oil and gas)from hydrocracking reaction is cooled via high pressure air cooler.When the temperature drops to the dew point,NH4Cl-NH4HS ammonium salt precipitation and scaling and H2S+H2O acid corrosion are produced in the dew point and its extension zone.NH4Cl-NH4HS ammonium salt precipitates out and forms scale inside the tube bundle of air cooler,which increases the pressure drop of the system,increases the material flow resistance and easily causes tube bundle blockage.The H2S+H2O acid corrosion results in the thinning and perforation of the tube bundle of air cooler.In order to inhibit the scaling blockage and acid corrosion of the tube bundle of high pressure air cooler,scale and corrosion inhibitor is injected upstream the high pressure air cooler in hydrocracking unit.After injecting the scale and corrosion inhibitor,the iron ion content of the condensed acid water removed from high pressure separator is less than 3 mg/L,meeting the requirements of the Measures for Corrosion Monitoring and Administration of PetroChina’s Refining and Petrochemical Enterprises.The differential pressure in the high pressure air cooler decreases from 0.3 MPa to 0.1 MPa,showing that there is no scaling blockage in the tube bundle of air cooler.The equipment corrosion and tube bundle scaling blockage of the high pressure air cooler in hydrocracking unit is effectively controlled,ensuring the safe,smooth and long-term operation of the hydrocracking unit.