Study on Corrosion and Protection of Process Pipeline for Marine High Acid Crude Oil Processing

The marine high acid crude oil processed in Oil & Gas development & Utilization Co., CNOOC has high density, high acid value and the electric desalting difficulties. Due to the characteristics of marine high acid crude oil, low temperature hydrochloric acid corrosion and high temperature naphthenic acid corrosion is the tough problem in the atmospheric and vacuum crude distillation tower system. According to the corrosion investigations and researches on subsidiaries of Oil & Gas development & Utilization Co., CNOOC, this article summarized corrosion problems and existing protection measures in subsidiaries and provided effective methods for anticorrosion. These methods include modified technology of crude oil electric desalting, alkali liquor injection technology, improved "three injection" technology at low temperature parts, standardized corrosion monitoring and so on.

Key words: Marine high acid crude oil; Atmospheric and vacuum distillation unit; Equipment and pipelines; Corrosion and protection.

海洋高酸原油在加工过程中不仅高温部位设备管线环烷酸腐蚀严重，而且由于电脱盐困难，脱后含盐高，造成常减压装置初顶、常顶和减顶部位及冷凝冷却系统设备管线的严重腐蚀，有的甚至造成下游催化装置、焦化装置及加氢装置低温部位和高温部位设备管线的腐蚀。严重影响和制约了装置的长周期安全平稳运行，也影响了企业的经济效益。为了减轻设备管线腐蚀，延长装置开工周期，油气公司各企业根据各自实际情况采取了一系列设备管线防腐蚀措施，有效的减轻了装置的设备管线腐蚀，延长了开工周期，确保了装置的长周期安全平稳运行。