DUPONT工艺硫酸烷基化装置的腐蚀与防护

Corrosion of Sulfuric Acid Alkylation Unit of DUPONT Process and Protection

中海炼化惠州炼油分公司160 kt/a硫酸烷基化装置自开工以来运行超过2年,生产设备运行良好,但是浓硫酸及其混合物和烷基化附产物在装置流程中引起的腐蚀还是存在,局部位置腐蚀严重,个别管线及部件出现了穿孔、分馏部分的空冷管束减薄。为了全面了解装置的腐蚀情况,在停工期间公司对装置进行了全面的腐蚀调查和分析,发现总体设备良好,但在酸碱中和混流局部、流态复杂部位和浓硫酸流速偏高等部位腐蚀问题突出,必须对酸碱混流、酸泵出口等局部进行材质升级;对设计不合理造成酸流速高的部位进行改造;在分馏系统应增设监控设施。

The 160,000 TPY sulfuric acid alkylation unit in CNOOC Huizhou Refining ＆ Chemical Company has been operating very stably ever since it was started - up 2 years ago. But the corrosion of concentrated sulfuric acid, acid - alkali mixture and the reaction by - products existed in unit operation, and some local corrosion was serious. Some pipelines suffered from corrosion failures and air cooler tubes of distillation unit became increasingly thinner. In order to have a full knowledge of the corrosion in the unit, a comprehensive corrosion investigation was made in the scheduled shutdown for maintenance of the unit. The investigation found that, most of equipment was in good conditions, the corrosions were obvious in the locations where there was acid and caustic neutralization, the flow state was very complex and flow velocity of concentrated sulfuric acid was high. It is recommended that the materials for mixed flow of acid and caustic, outlet of acid pump should be upgraded, the location where the acid flow velocity is high should be revamped and corrosion monitoring system should be provided for the distillation unit.