常减压蒸馏装置加工南帕斯凝析油的腐蚀与防护

中国石油化工股份有限公司茂名分公司3号常减压蒸馏装置配炼伊朗南帕斯凝析油后出现泄漏着火事故后,对1,2,3和4号配炼南帕斯凝析油的常减压蒸馏装置的初馏塔、常压塔和减压塔进行了检测,发现4套装置均有严重的腐蚀减薄现象。塔顶腐蚀为HCl-H2S-H2O腐蚀,而塔顶冷凝器在流速小于6 m/s时,以HCl腐蚀为主;在流速大于6 m/s时,以酸性水腐蚀为主,且腐蚀速率随流速增加而增加。对腐蚀严重的常压塔上部采用材质升级（整体内衬3 mm双相钢2205）;增加注水管对换热器进行清洗,同时更换为螺旋折流板换热器,以减少垢下腐蚀;调整工艺操作,严格控制塔顶温度和回流温度,在电脱盐后管线上按2.5 g/t油的量注入质量分数为4%的氢氧化钠等措施后,常压塔顶冷却器的腐蚀速率和污水中氯离子的质量分数均下降了80%,取得了较好效果。

Corrosion of of Atmospheric - vacuum Distillation Unit Processing South Pars Crude

When the leaking fire occurred in the No 3 atmospheric-vacuum distillation unit in SINOPEC Maoming Petrochemical Company,not long after it began to blend Iranian South Pars crude into the feedstock.The examinations were carried out in 3 overheads of the primary tower,atmospheric tower and vacuum tower of No.1,No.2,No.3 and No.4 atmospheric distillation units,and serious corrosions and corrosion thinning have been found in these four units.The tower overhead corrosion is mainly HCl-H2S-H2O corrosion.When the velocity of overhead condenser is lower than 6 m / s,the HCl corrosion dominates.When it is great than 6 m / s,the corrosion is mainly sour water corrosion,and the corrosion rate increases with higher flow velocity.The corrosion rate of overhead coolers of atmospheric tower and chlorine ions in waste water were reduced by 80% and good results had been achieved after material upgrading of top section of atmospheric tower(integrally lined with 3 mm duplex steel 2205),addition of water injection line to clean heat exchangers,replacement of heliexchanger to reduce under-deposit fouling corrosion,adjustment of process operation to strictly control the overhead temperature and reflux temperature and addition of 4% NaOH into the desalted oil line at a dosage of 2.5 g / t of oil.